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Sample records for holm oak quercus

  1. The bark of holm oak (Quercus ilex, L.) for airborne Cr(VI) monitoring.

    Science.gov (United States)

    Minganti, Vincenzo; Drava, Giuliana; De Pellegrini, Rodolfo; Anselmo, Marco; Modenesi, Paolo; Malaspina, Paola; Giordani, Paolo

    2015-01-01

    In this work, the bark of holm oak was used as a bioindicator to study the atmospheric distribution of Cr(VI). The chosen method (alkaline extraction and atomic absorption determination) was found in the literature, adapted for use with the matrix involved, and validated. The method had some limits, but provided an excellent estimation of Cr(VI) concentrations with good sensitivity and a reasonable time of analysis and cost. Thirty-four samples of holm oak collected in three areas characterised by different possible sources of pollution (the area near a former chromate production plant, an urban area, and a rural "reference" area) were analysed, obtaining concentrations ranging from 1.54 to 502 μg g(-1) near the industrial plant, ranging from 0.22 to 1.35 μg g(-1) in the urban area, and mostly below the detection limit (0.04 μg g(-1)) in the rural area. The bark of holm oak proved to be a good bioindicator to detect Cr(VI) in the environment. The extraction procedure followed by atomic absorption analysis is simple, provides good sensitivity, and it is suitable for environmental studies.

  2. A method to quantify infection and colonization of holm oak (Quercus ilex) roots by Phytophthora cinnamomi.

    Science.gov (United States)

    Ruiz-Gómez, Francisco J; Sánchez-Cuesta, Rafael; Navarro-Cerrillo, Rafael M; Pérez-de-Luque, Alejandro

    2012-01-01

    Phytophthora cinnamomi Rands. is an important root rot pathogen widely distributed in the north hemisphere, with a large host range. Among others diseases, it is known to be a principal factor in the decline of holm oak and cork oak, the most important tree species in the "dehesa" ecosystem of south-western Spain. Previously, the focus of studies on P. cinnamomi and holm oak have been on molecular tools for identification, functional responses of the host, together with other physiological and morphological host variables. However, a microscopic index to describe the degree of infection and colonization in the plant tissues has not yet been developed. A colonization or infection index would be a useful tool for studies that examine differences between individuals subjected to different treatments or to individuals belonging to different breeding accessions, together with their specific responses to the pathogen. This work presents a methodology based on the capture and digital treatment of microscopic images, using simple and accessible software, together with a range of variables that quantify the infection and colonization process.

  3. A method to quantify infection and colonization of holm oak (Quercus ilex roots by Phytophthora cinnamomi

    Directory of Open Access Journals (Sweden)

    Ruiz-Gómez Francisco J

    2012-09-01

    Full Text Available Abstract Phytophthora cinnamomi Rands. is an important root rot pathogen widely distributed in the north hemisphere, with a large host range. Among others diseases, it is known to be a principal factor in the decline of holm oak and cork oak, the most important tree species in the “dehesa” ecosystem of south-western Spain. Previously, the focus of studies on P. cinnamomi and holm oak have been on molecular tools for identification, functional responses of the host, together with other physiological and morphological host variables. However, a microscopic index to describe the degree of infection and colonization in the plant tissues has not yet been developed. A colonization or infection index would be a useful tool for studies that examine differences between individuals subjected to different treatments or to individuals belonging to different breeding accessions, together with their specific responses to the pathogen. This work presents a methodology based on the capture and digital treatment of microscopic images, using simple and accessible software, together with a range of variables that quantify the infection and colonization process.

  4. Anti nutritional evaluation of the flour of the nipples of holm oak (quercus ilex) and oak cork (quercus suber) Raw and pressure-sealed

    Energy Technology Data Exchange (ETDEWEB)

    El Mahi, F. Z.

    2009-07-01

    The present study contributes to the development of the food potential of the nipples of oak like new resources likely to be exploited on an industrial scale for their use in animal feeds. Our work relates to two species S of nipples of oak, edible, the homl oak and the other fodder one, the oal cork known for their spontaneousness and their vey significant geographical distribution. (Author)

  5. Habitat Fragmentation can Modulate Drought Effects on the Plant-soil-microbial System in Mediterranean Holm Oak (Quercus ilex) Forests.

    Science.gov (United States)

    Flores-Rentería, Dulce; Curiel Yuste, Jorge; Rincón, Ana; Brearley, Francis Q; García-Gil, Juan Carlos; Valladares, Fernando

    2015-05-01

    Ecological transformations derived from habitat fragmentation have led to increased threats to above-ground biodiversity. However, the impacts of forest fragmentation on soils and their microbial communities are not well understood. We examined the effects of contrasting fragment sizes on the structure and functioning of soil microbial communities from holm oak forest patches in two bioclimatically different regions of Spain. We used a microcosm approach to simulate the annual summer drought cycle and first autumn rainfall (rewetting), evaluating the functional response of a plant-soil-microbial system. Forest fragment size had a significant effect on physicochemical characteristics and microbial functioning of soils, although the diversity and structure of microbial communities were not affected. The response of our plant-soil-microbial systems to drought was strongly modulated by the bioclimatic conditions and the fragment size from where the soils were obtained. Decreasing fragment size modulated the effects of drought by improving local environmental conditions with higher water and nutrient availability. However, this modulation was stronger for plant-soil-microbial systems built with soils from the northern region (colder and wetter) than for those built with soils from the southern region (warmer and drier) suggesting that the responsiveness of the soil-plant-microbial system to habitat fragmentation was strongly dependent on both the physicochemical characteristics of soils and the historical adaptation of soil microbial communities to specific bioclimatic conditions. This interaction challenges our understanding of future global change scenarios in Mediterranean ecosystems involving drier conditions and increased frequency of forest fragmentation.

  6. Silvicultural options in ageing holm oak (Quercus ilex L. coppices in Gargano: results after 14 growing seasons

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    Scopigno D

    2008-12-01

    Full Text Available In the frame of a long-term research program concerning management of ageing holm oak coppices, results available after 14 growing seasons are reported in present paper. Experimental treatments include: A 50 standards per hectare, all of the same age; B 250 standards per hectare, all of the same age; C 140 standards per hectare, with two different ages; D conversion to high forest; E natural evolution (control. A total of 15 permanent plots were established (5 treatments x 3 replicates per treatment and the experimental design used is that of randomised blocks. Based on observations concerning seedlings and shoots development and standards growth and competitive effects, the following preliminary results may be highlighted: i recovering the traditional coppicing system with few standards per hectare represents a valid option from both ecological and shoots growth point of view; the stools, with few standards per hectare, showed a larger number of sprouts, provided with a higher average height and larger diameters; ii uneven-aged standards represent a good alternative form the points of view of both landscape impact immediately after felling operations and stand resistance to climatic damages; iii a good alternative is to apply conversion treatments to high forest, whenever their site quality allows these operations.

  7. Establishment limitation of holm oak (Quercus ilex subsp ballota (Desf.) Samp.) in a Mediterranean savanna - forest ecosystem

    NARCIS (Netherlands)

    Smit, Christian; Diaz, Mario; Jansen, Patrick

    2009-01-01

    Tree recruitment in Mediterranean savannas is generally hampered, in contrast with the original oak forests where these savannas are derived from. We asked whether this difference in recruitment success can be explained by differential post-dispersal survival. For one year we monitored experimentall

  8. Wettability and water uptake of holm oak leaf surfaces

    OpenAIRE

    2014-01-01

    Plant trichomes play important protective functions and may have a major influence on leaf surface wettability. With the aim of gaining insight into trichome structure, composition and function in relation to water-plant surface interactions, we analyzed the adaxial and abaxial leaf surface of Quercus ilex L. (holm oak) as model. By measuring the leaf water potential 24 h after the deposition of water drops on to abaxial and adaxial surfaces, evidence for water penetration through the upper l...

  9. Response of Holm oak (Quercus ilex subsp. ballota) and mastic shrub (Pistacia lentiscus L.) seedlings to high concentrations of Cd and Tl in the rhizosphere.

    Science.gov (United States)

    Domínguez, María T; Marañón, Teodoro; Murillo, José Manuel; Redondo-Gómez, Susana

    2011-05-01

    The impairment of root growth and photosynthetical functioning are the main impacts of trace elements on woody plant seedlings. In this work, we assessed the response of Holm oak (Quercusilex subsp. ballota) and mastic shrub (Pistacia lentiscus) seedlings to high concentrations of Cd and Tl in the rhizosphere. These are non-essential trace elements, with a potential high mobility in the soil-plant system. Seedlings of these species are frequently used in the afforestation of degraded soils in mining areas. Plants were exposed to different levels of Cd (20, 80 and 200 mg L(-1)) and Tl (2, 10 and 20 mg L(-1)) in a sand culture. Biomass allocation, growth rates, chlorophyll fluorescence and gas exchange were studied. Both metals affected root biomass. Cadmium produced an increase in the root mass ratio and a decrease in the specific leaf area of the plants in oak seedlings, while Tl did not provoke such response. Mastic plants were more sensitive to Tl and Cd than oak plants. Between elements, Tl provoked more severe toxic effects in the plants, affecting the antennae complexes and reaction centers of the photosystem II. Both elements decreased net assimilation rates (down to a 20% of the control plants) and stomatal conductance (5-10% of the values for the control plants). Cadmium was highly retained in the roots of both species, while Tl was highly translocated into the leaves. In general, Holm oak showed a higher tolerance for Cd than for Tl, and a higher resistance to both metals than mastic shrub, due to a high capacity for Cd retention at the root level. However, such accumulation in roots may induce water stress in the seedling exposed to Cd.

  10. Adsorption of Disperse Orange 30 dye onto activated carbon derived from Holm Oak (Quercus Ilex) acorns: A 3(k) factorial design and analysis.

    Science.gov (United States)

    Tezcan Un, Umran; Ates, Funda; Erginel, Nihal; Ozcan, Oznur; Oduncu, Emre

    2015-05-15

    In this study, samples of activated carbon were prepared from Holm Oak acorns by chemical activation with H3PO4, ZnCl2 and KOH as activating agents. The samples were characterized by SEM, BET, FTIR and elemental analysis, and were then evaluated for the removal of Disperse Orange 30 (DO30) dyes from aqueous solutions. A 3(k) factorial design was used to determine the interaction effects of carbonization temperature, pH, dosage of adsorbent and type of activating agent on the amount of dye removal. Also, level of effectiveness factors were determined by conducting regression models for maximum adsorption efficiency. Of all the samples, the sample generated using ZnCl2 as an activating agent showed a maximum dye removal efficiency of 93.5% at a carbonization temperature of 750 °C, a pH of 2 and an adsorbent dosage of 0.15 g/25 ml. The analysis shows that the adsorption process depends significantly on the type of activating agent used in the preparation of activated carbon.

  11. Quercus kelloggii Newb., California black oak

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    P.M. McDonald

    1990-01-01

    California black oak (Quercus kelloggii) exceeds all other California oaks in volume, distribution, and altitudinal range. Yet this deciduous hardwood has had little sustained commercial use and almost no management, even though its wood closely resembles that of its valuable, managed, and heavily used counterpart-northern red oak (...

  12. LIDAR-based estimation of leaf area index on Holm oak [Quercus ilex L. subsp. ballota (Desf.) Samp.] trees; Aplicacion de imagenes LIDAR para la estimacion de indices de superficie foliar (LAI) en encinas [Quercus ilex L. subsp. Ballota (Desf.) Samp.

    Energy Technology Data Exchange (ETDEWEB)

    Navarro Cerrillo, R. M.; Sanchez de la Orden, M.; Gomez Bonilla, J.; Garcia-Ferrer, A.; Hernandez Clemente, R.; Lanjeri, S.

    2010-07-01

    The aim of this paper was to estimate Leaf Area Index (LAI) of Quercus ilex by calculating the laser-intercepted rate through the forest canopy using LiDAR data. LAI was measured in 40 trees with a hemispheric camera (NIKON Coolpix 4500) and coincided with the acquisition of LIDAR data. The LiDAR-derived LAILIDAR was then estimated by applying a value of the inverse of the coefficient of extinction of 1/K 1.48. The in-field LAI values varied between 1.01 m{sup 2} m{sup -}2 and 1.61 m{sup 2} m{sup -}2. From a comparison of the LiDAR-derived to the field-derived LAI, the coefficients of the determination for the coefficient of extinction of 1.48 was R{sup 2} = 0.60 (RMSE = 0.16) for quadratic and R{sup 2} = 0.62 (RMSE = 0.21) for potential correlations. The change in accuracy was attributed to the density of leaves, the interference by stems, and the vertical number of branches in the forest stands. The LIDAR sensor technique gives a satisfactory result in the obtainment of leaf parameters in Holm oak trees, although its generalisation on field studies depends on its cost and suitability to be applied over large surfaces. (Author) 33 refs.

  13. Impact of straw and rock-fragment mulches on soil moisture and early growth of holm oaks in a semiarid area

    Science.gov (United States)

    M. N. Jimenez; J. R. Pinto; M. A. Ripoll; A. Sanchez-Miranda; F. B. Navarro

    2017-01-01

    Planted seedlings and saplings usually exhibit low survival and growth rates under dry Mediterranean environments, especially late-successional species such as Quercus. In this work, we studied the effects of straw and rock fragment mulches on the establishment conditions of holm oak (Quercus ilex L. subsp. ballota (Def.) Samp.) in SE Spain. Soil moisture was...

  14. Biochemical, physiological and climatic influence on the emission of isoprenoides from Grey Poplar (Populus x canescens (Aiton) Sm.) and Holm Oak (Quercus ilex L.); Biochemische, physiologische und klimatische Einfluesse auf die Isoprenoidemission der Graupappel (Populus x canescens (Aiton) Sm.) und der Steineiche (Quercus ilex L.)

    Energy Technology Data Exchange (ETDEWEB)

    Mayrhofer, S.

    2007-05-15

    Because of their important role for the atmospheric chemistry, global daily and seasonal emission rates of isoprene and monoterpenes have to be estimated with accuracy. Therefore, detailed knowledge of biochemical and physiological processes within the plant metabolism has to be gathered. Afterwards the gained cognitions are used as information for process-based model calculations. The major scope of the work was therefore to enlarge basic knowledge of the regulation of isoprenoid emission, which is known to be dependent on several environmental factors, especially light and temperature. Measurements of diurnal isoprene emission have been performed in parallel on physiological, translational and transcriptional level on leaves of Grey Poplar (Populus x canescens), a strong isoprene emitting species. Additionally, examinations of diurnal monoterpene emission in connection to physiologic and enzymatic processes was conducted in leaves of Holm Oak (Quercus ilex), which emits a large spectrum of monoterpenes. Furthermore a hypothesis was tested, whether isoprene emission may serve the plant as antioxidative protection mechanism in order to overcome oxidative stress. In main parts, the following results have been reached: 1. In the first part of this work, isolation of PcDXR (DXR of Grey Poplar) from a cDNA-Genbank and heterologous expression of the isolated gene was accomplished. 2. Daytime variation of physiological and biochemical parameters of the isoprene emission of Grey Poplar was measured twice on 2 following days in 2 years. All together, measurements have been performed on 8 representative plants. 3. Quantitative RT-PCR elucidated the gene expression pattern of PcDXR and PcISPS in parallel to diurnal gas exchange measurements. Gene expression of PcISPS showed distinct diurnal courses with maximum values on the late morning, whereas PcDXR transcript levels stayed consistent over the day. No short-term influence of PPFD and leaf temperature has been observed on

  15. Comparison among methods for the assessment of deadwood volume in a former holm oak coppice

    Directory of Open Access Journals (Sweden)

    Bianchi L

    2013-04-01

    Full Text Available Comparison among methods for the assessment of deadwood volume in a former holm oak coppice. The paper aims to compare three methods for the assessment of deadwood volume, i.e., LIS (Line Intersect System, FAS (Fixed Area Sampling, and WM (Weighings Method. The control data are represented by the outputs of Xylometric measurement. The study was carried out in a former holm oak (Quercus ilex L. coppice located in the nature park of Montioni in southern Tuscany. LIS and FAS overestimated significantly the quantity of deadwood (+12% and +50%, respectively. The error become higher as the minimum threshold sampling increases. The WM, besides the operational complexity of its application, led to more promising and precise results.

  16. Phylogeographical Variation of Chloroplast DNA in Cork Oak (Quercus suber)

    OpenAIRE

    Lumaret, Roselyne; TRYPHON-DIONNET, MATHIEU; MICHAUD, HENRI; SANUY, AURÉLIE; IPOTESI, EMILIE; Born, Céline; MIR, CÉLINE

    2005-01-01

    • Background and Aims In the last decades, the geographical location of the centre of origin of Quercus suber (cork oak), a strictly western Mediterranean oak species, has been the subject of controversy.

  17. Wettability, polarity, and water absorption of holm oak leaves: effect of leaf side and age.

    Science.gov (United States)

    Fernández, Victoria; Sancho-Knapik, Domingo; Guzmán, Paula; Peguero-Pina, José Javier; Gil, Luis; Karabourniotis, George; Khayet, Mohamed; Fasseas, Costas; Heredia-Guerrero, José Alejandro; Heredia, Antonio; Gil-Pelegrín, Eustaquio

    2014-09-01

    Plant trichomes play important protective functions and may have a major influence on leaf surface wettability. With the aim of gaining insight into trichome structure, composition, and function in relation to water-plant surface interactions, we analyzed the adaxial and abaxial leaf surface of holm oak (Quercus ilex) as a model. By measuring the leaf water potential 24 h after the deposition of water drops onto abaxial and adaxial surfaces, evidence for water penetration through the upper leaf side was gained in young and mature leaves. The structure and chemical composition of the abaxial (always present) and adaxial (occurring only in young leaves) trichomes were analyzed by various microscopic and analytical procedures. The adaxial surfaces were wettable and had a high degree of water drop adhesion in contrast to the highly unwettable and water-repellent abaxial holm oak leaf sides. The surface free energy and solubility parameter decreased with leaf age, with higher values determined for the adaxial sides. All holm oak leaf trichomes were covered with a cuticle. The abaxial trichomes were composed of 8% soluble waxes, 49% cutin, and 43% polysaccharides. For the adaxial side, it is concluded that trichomes and the scars after trichome shedding contribute to water uptake, while the abaxial leaf side is highly hydrophobic due to its high degree of pubescence and different trichome structure, composition, and density. Results are interpreted in terms of water-plant surface interactions, plant surface physical chemistry, and plant ecophysiology.

  18. Indirect effects of tending ants on holm oak volatiles and acorn quality.

    Science.gov (United States)

    Paris, Carolina I; Llusia, Joan; Peñuelas, Josep

    2011-04-01

    The indirect effect of ants on plants through their mutualism with honeydew-producing insects has been extensively investigated. Honeydew-producing insects that are tended by ants impose a cost on plant fitness and health by reducing seed production and/or plant growth. This cost is associated with sap intake and virus transmissions but may be overcompesated by tending ants if they deter or prey on hebivorous insects. The balance between cost and benefits depends on the tending ant species. In this study we report other indirect effects on plants of the mutualism between aphids and ants. We have found that two Lasius ant species, one native and the other invasive, may change the composition of volatile organic compounds (VOCs) of the holm oak (Quercus ilex) blend when they tend the aphid Lachnus roboris. The aphid regulation of its feeding and honeydew production according to the ant demands was proposed as a plausible mechanism that triggers changes in VOCs. Additionally, we now report here that aphid feeding, which is located most of the time on acorns cap or petiole, significantly increased the relative content of linolenic acid in acorns from holm oak colonized by the invasive ant. This acid is involved in the response of plants to insect herbivory as a precursor or jasmonic acid. No effect was found on acorn production, germination or seedlings quality. These results suggest that tending-ants may trigger the physiological response of holm oaks involved in plant resistance toward aphid herbivory and this response is ant species dependant.

  19. Macrofungi diversity in cork-oak and holm-oak Woodlands in Alentejo (Southern Portugal)

    OpenAIRE

    Santos-Silva,Celeste; Louro, Rogério

    2011-01-01

    With the purpose of contributing to a better knowledge of the Portuguese mycota, a compilation study of the macrofungal diversity of cork-oak and holm-oak woodlands (montado/dehesas) of Alentejo, Southern Portugal was made. This work is based on a series of macrofungi surveys, carried out by the authors, between 2005 and 2011, in six representative sites. Taxonomy and nomenclature follows Kirk et al. (2001) and Kirk (2004-2011). Current species distribution was consulted in: online intern...

  20. Wettability, Polarity, and Water Absorption of Holm Oak Leaves: Effect of Leaf Side and Age1[OPEN

    Science.gov (United States)

    Fernández, Victoria; Sancho-Knapik, Domingo; Guzmán, Paula; Peguero-Pina, José Javier; Gil, Luis; Karabourniotis, George; Khayet, Mohamed; Fasseas, Costas; Heredia-Guerrero, José Alejandro; Heredia, Antonio; Gil-Pelegrín, Eustaquio

    2014-01-01

    Plant trichomes play important protective functions and may have a major influence on leaf surface wettability. With the aim of gaining insight into trichome structure, composition, and function in relation to water-plant surface interactions, we analyzed the adaxial and abaxial leaf surface of holm oak (Quercus ilex) as a model. By measuring the leaf water potential 24 h after the deposition of water drops onto abaxial and adaxial surfaces, evidence for water penetration through the upper leaf side was gained in young and mature leaves. The structure and chemical composition of the abaxial (always present) and adaxial (occurring only in young leaves) trichomes were analyzed by various microscopic and analytical procedures. The adaxial surfaces were wettable and had a high degree of water drop adhesion in contrast to the highly unwettable and water-repellent abaxial holm oak leaf sides. The surface free energy and solubility parameter decreased with leaf age, with higher values determined for the adaxial sides. All holm oak leaf trichomes were covered with a cuticle. The abaxial trichomes were composed of 8% soluble waxes, 49% cutin, and 43% polysaccharides. For the adaxial side, it is concluded that trichomes and the scars after trichome shedding contribute to water uptake, while the abaxial leaf side is highly hydrophobic due to its high degree of pubescence and different trichome structure, composition, and density. Results are interpreted in terms of water-plant surface interactions, plant surface physical chemistry, and plant ecophysiology. PMID:24913938

  1. In vitro propagation of northern red oak (Quercus rubra L.)

    Science.gov (United States)

    G. Vengadesan; Paula M. Pijut

    2009-01-01

    In vitro propagation of northern red oak (Quercus rubra) shoots was successful from cotyledonary node explants excised from 8-wk-old in vitro grown seedlings. Initially, four shoots per explant were obtained on Murashige and Skoog (MS) medium supplemented with 4.4 µM 6-benzylaminopurine (BA), 0.45 ...

  2. Cork oak (Quercus suber L.) site rating

    OpenAIRE

    Gonçalves, Ana Cristina; Saraiva Dias, Susana; Gonçalves Ferreira, Alfredo; Ribeiro, Nuno de Almeida

    2004-01-01

    Alentejo cork oak stands are crucial in terms of cork production and sustainability of agrosilvopastoral systems, therefore the development of a tool that allows site zoning, according to cork oak establishment and growth potentials is worthwhile. The site potential and consequently tree development are mainly governed by soil characteristics such as depth, permeability, chemistry, internal drainage, runoff and climate characteristics such as precipitation and temperature. A cork oak site-rat...

  3. Cork Oak Trees (Quercus suber L.).

    Science.gov (United States)

    Alvarez, Rubén; Toribio, Mariano; Cortizo, Millán; Ordás Fernández, Ricardo-Javier

    2006-01-01

    A transformation system for selected mature Quercus suber L. trees using Agrobacterium tumefaciens has been established. Embryos obtained from recurrent proliferating embryogenic masses are inoculated with AGL1 strain harbouring the plasmid pBINUbiGUSint, which carries the nptII and uidA genes. Evidence of stable transgene integration is obtained by polymerase chain reaction for nptII and uidA genes, Southern blotting and expression of the uidA gene. The transgenic embryos are germinated and successfully transferred to soil.

  4. Improved genetic transformation of cork oak (Quercus suber L.).

    Science.gov (United States)

    Alvarez-Fernández, Rubén; Ordás, Ricardo-Javier

    2012-01-01

    An Agrobacterium-mediated transformation system for selected mature Quercus suber L. trees has been established. Leaf-derived somatic embryos in an early stage of development are inoculated with an AGL1 strain harboring a kanamycin-selectable plasmid carrying the gene of interest. The transformed embryos are induced to germinate and the plantlets transferred to soil. This protocol, from adult cork oak to transformed plantlet, can be completed in about one and a half years. Transformation efficiencies (i.e., percentage of inoculated explants that yield independent transgenic embryogenic lines) vary depending on the cork oak genotype, reaching up to 43%.

  5. Urban and industrial contribution to trace elements in the atmosphere as measured in holm oak bark

    Science.gov (United States)

    Drava, Giuliana; Brignole, Daniele; Giordani, Paolo; Minganti, Vincenzo

    2016-11-01

    The concentrations of As, Cd, Co, Cu, Fe, Mn, Ni, Pb, V and Zn were measured by ICP-OES in samples of bark of the holm oak (Quercus ilex L.) collected from trees in different urban environments (residential and mixed residential/industrial). The use of tree bark as a bioindicator makes it easy to create maps that can provide detailed data on the levels and on the spatial distribution of each trace element. For most of the elements considered (As, Co, Fe, Mn, Ni, V and Zn), the concentrations in the industrial sites are about twice (from 1.9 to 2.8 times higher) of those in the residential area. Arsenic, Fe and Zn show the highest concentrations near a steel plant (operational until 2005), but for the other elements it is not possible to identify any localized source, as evident from the maps. In areas where urban pollution is summed up by the impact of industrial activities, the population is exposed to significantly higher amounts of some metals than people living in residential areas.

  6. Frost-acclimation of photosynthesis in overwintering Mediterranean holm oak, grown in Central Europe

    Directory of Open Access Journals (Sweden)

    Ellen Pflug

    2012-03-01

    Full Text Available As a consequence of global change, forestry in Central Europe has to expect and be prepared for an increase of hot and dry summers in the near future. In two model plantations of the Mediterranean holm oak (Quercus ilex L. in Central Europe (Rhine-Main basin we tested its potential as a future forestry tree for drought-threatened stands by studying its overwintering strategy under harsh winter conditions. During prolonged frost periods, chronic photoinhibition was developed, which lasted until the end of the frost period. Nearly all plants survived minimum temperatures of - 16 to -18°C and their photosynthetic apparatus recovered completely during late winter. A detailed study of the temperature dependence of chlorophyll (chl fluorescence parameters of the OJIP test revealed statistically significant correlations between minimum temperature and maximum quantum yield of primary photochemistry (Fv/Fm, absorption rate/reaction centre (ABS/RC, dissipation rate/reaction centre (DI0/RC and electron transport rate/reaction centre (ET0/RC as well as with the deepoxidation state (DES of the xanthophyll pigments. The DES correlated with Fv/Fm, ABS/RC, DI0/RC and ET0/RC. It is concluded, that from the point of view of the winter hardiness of the photosynthetic apparatus, Q. ilex should be further investigated as a potential future forestry tree also for very dry and warm stands in Central Europe under the scenarios of climate change.

  7. Detection of hybrids in nature: application to oaks (Quercus suber and Q. ilex).

    Science.gov (United States)

    Burgarella, C; Lorenzo, Z; Jabbour-Zahab, R; Lumaret, R; Guichoux, E; Petit, R J; Soto, A; Gil, L

    2009-05-01

    Powerful and accurate detection of first-generation (F1) hybrids and backcrosses in nature is needed to achieve a better understanding of the function and dynamics of introgression. To document the frequency of ongoing interspecific gene exchange between two Mediterranean evergreen oaks, the cork oak (Quercus suber) and the holm oak (Q. ilex), we analyzed 1487 individuals originating from across the range of the two species using eight microsatellite loci and two Bayesian clustering approaches (implemented in the programs STRUCTURE and NEWHYBRIDS). Simulated data were used to assess the differences between the two clustering methods and to back up the choice of the threshold value for the posterior probability to discriminate admixed from pure individuals. We found that the use of STRUCTURE resulted in the highest power to detect hybrids, whereas NEWHYBRIDS provided the highest accuracy. Irrespective of the approach, the two species were clearly distinguished as independent genetic entities without any prior information. In contrast with previous reports, we found no evidence for unidirectional introgression. The overall hybridization rate was very low (<2% of introgressed individuals). Only two individuals were identified as F1 hybrids and five as early backcrosses. This work shows that the combined application of the two complementary Bayesian approaches and their systematic validation with simulations, fit for the case at hand, helps gain resolution in the identification of admixed individuals.

  8. Frequent cytoplasmic exchanges between oak species that are not closely related: Quercus suber and Q. ilex in Morocco.

    Science.gov (United States)

    Belahbib, N; Pemonge, M H; Ouassou, A; Sbay, H; Kremer, A; Petit, R J

    2001-08-01

    Chloroplast (cp) and mitochondrial (mt) DNA variation were studied in 97 populations of cork oak (Quercus suber) in Morocco; in 31 of these populations, holm oak (Quercus ilex), a clearly distinct species, also occurred and was compared with Q. suber. Three cpDNA and one mtDNA primer pairs were used in the survey, each in combination with one restriction enzyme. Six haplotypes belonging to two very divergent lineages were detected; one lineage predominates in each species, and is probably ancestral, as inferred from comparisons with other oak species. In the mixed-species populations, cytoplasmic genomes were frequently shared across species, as indicated by an introgression ratio of 0.63. This index is a new measure of the propensity of species to share locally genetic markers, varying from zero (complete differentiation) to one (no differentiation). By contrast, more closely related deciduous oak species (Q. robur, Q. petraea and Q. pubescens) have introgression ratios varying from 0.82 to 0.97. The introgression events appear to have been more frequent in the direction Q. ilex (female) x Q. suber (male), a finding which seems attributable to the flowering phenology of these two species. This asymmetry may have favoured immigration of Q. suber beyond its main range, in regions already colonized by Q. ilex. There, rare hybridization and further introgression through long distance pollen flow have established populations that are morphologically indistinguishable from Q. suber but that have cytoplasmic genomes originating from the local Q. ilex populations.

  9. The taxonomic status of the Mexican oak Quercus undata (Fagaceae, Quercus, Section Quercus El estatus taxonómico del encino mexicano Quercus undata (Fagaceae, Quercus, Sección Quercus

    Directory of Open Access Journals (Sweden)

    Jeffrey R. Bacon

    2011-12-01

    Full Text Available Quercus undata Trel. (Fagaceae, Quercus, Section Quercus has a complex taxonomic and nomenclatural history. Intensive sampling of oaks at the type locality of Q. undata Trel. in Durango, Mexico and evaluation of herbarium specimens and plants in the field indicate that Q. undata represents variation in Quercus chihuahuensis Trel. in white oak communities where introgressive hybridization among Q. chihuahuensis, Q. grisea Liebm., and a third white oak, Q. arizonica Sarg. made species identification difficult. Endlich's type specimen of Q. undata, as designated by Trelease, was apparently destroyed in bombing raids on Berlin during World War II, and we propose herein as lectotype the Trelease illustration of the type. An epitype is also designated in support of the lectotype, given that some features cannot be critically observed on the illustration. The long peduncles of the specimen illustrated by Trelease indicate a close relation to Q. chihuahuensis.Quercus undata Trel. (Fagaceae, Quercus, Section Quercus tiene una compleja historia taxonómica y de nomenclatura. Un muestreo intensivo de los encinos en la localidad tipo de Q. undata en Durango, México y análisis de ejemplares en herbario y en el campo indican que Q. undata representa variación en Q. chihuahuensis Trel. en los sitios donde la hibridación introgresiva entre Q. chihuahuensis, Q. grisea Liebm., y un tercer encino blanco, Q. arizonica Sarg., dificultan la identificación de especies. El ejemplar tipo designado por Trelease aparentemente fue destruido en el bombardeo de Berlín durante la Segunda Guerra Mundial, por lo que se propone como lectotipo a la ilustración del tipo en la obra de Trelease. Se designa también un epitipo dado que algunos rasgos no pueden ser críticamente observados en la ilustración. Los largos pedúnculos del espécimen ilustrado por Trelease indican la relación cercana a Q. chihuahuensis.

  10. Microsatellite Primer Development for Post Oak, Quercus stellata (Fagaceae

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    Warren B. Chatwin

    2014-10-01

    Full Text Available Premise of the study: The American Cross Timbers forest ecosystem runs from southeastern Kansas to Central Texas and is primarily composed of post oak (Quercus stellata. This old-growth forest currently occupies only about 2% of its ancestral range. To facilitate genetic research on this species, we developed microsatellite primers specific to post oak from reduced genomic libraries. Methods and Results: Two Q. stellata individuals, sampled from the northern and southern range of the post oak forest, were subject to genomic reduction and 454 pyrosequencing. Bioinformatic analysis identified putative microsatellites from which 12 polymorphic primer sets were screened on three populations. The number of alleles observed ranged from five to 20 across all populations, while observed and expected heterozygosity values ranged from 0.05 to 0.833 and 0.236 to 0.893, respectively, within individual populations. Conclusions: We report the development of microsatellite markers, specific to post oak, to aid the study of genetic diversity and population structure of extant forest remnants.

  11. Bioclimatic characteristic of oak species Quercus macranthera subsp. syspirensis and Quercus petraea subsp. pinnatiloba in Turkey.

    Science.gov (United States)

    Kargioglu, Mustafa; Serteser, Ahmet; Senkul, Cetin; Konuk, Muhsin

    2011-01-01

    This study was carried out to determine some bioclimatic characteristics such as humidity category (Q2), winter variant (m), the length of the dry season (LDS) and the dry season water deficit (DSWD) of naturally growing two endemic oak taxa, Quercus macranthera subsp. syspirensis and Q. petraea subsp. pinnatiloba, living in Turkey. Our findings showed that bioclimatic tolerance range of Q. macranthera subsp. syspirensis possess 7 different types of Mediterranean bioclimate while Q. petraea subsp. pinnatiloba had 8 of them. Although Q. macranthera subsp. syspirensis was ranging among the semiarid, freezing and very cold, Q. petraea subsp. pinnatiloba was among sub-humid, freezing and very cold ambient. It was briefly established that Q. macranthera subsp. syspirensis prefers semi-arid and very cold/freezing conditions and Q. petraea subsp. pinnatiloba prefers sub-humid and cold/very cold climatic conditions.

  12. The diversification of terpene emissions in Mediterranean oaks: lessons from a study of Quercus suber, Quercus canariensis and its hybrid Quercus afares.

    Science.gov (United States)

    Welter, Saskia; Bracho-Nuñez, Araceli; Mir, Céline; Zimmer, Ina; Kesselmeier, Jürgen; Lumaret, Roselyne; Schnitzler, Jörg-Peter; Staudt, Michael

    2012-09-01

    Interspecific gene flow is common in oaks. In the Mediterranean, this process produced geographical differentiations and new species, which may have contributed to the diversification of the production of volatile terpenes in the oak species of this region. The endemic North African deciduous oak Quercus afares (Pomel) is considered to be a stabilized hybrid between the evergreen Quercus suber (L.) and the deciduous Quercus canariensis (Willd.), presumably being monoterpene and isoprene emitters, respectively. In a common garden experiment, we examined the terpene emission capacities, terpene synthase (TPS) activities and nuclear genetic markers in 52 trees of these three oak species. All but one of the Q. suber and Q. canariensis trees were found to be genetically pure, whereas most Q. afares trees possessed a mixed genotype with a predominance of Q. suber alleles. Analysis of the foliar terpene emissions and TPS activities revealed that all the Q. canariensis trees strongly produced isoprene while all the Q. suber trees were strong monoterpene producers. Quercus afares trees produced monoterpenes as well but at more variable and significantly lower rates, and with a monoterpene pattern different than that observed in Q. suber. Among 17 individuals tested, one Q. afares tree emitted only an insignificant amount of terpenes. No mixed isoprene/monoterpene emitter was detected. Our results suggest that the capacity and pattern of volatile terpene production in Algerian Q. afares populations have strongly diverged from those of its parental species and became quantitatively and qualitatively reduced, including the complete suppression of isoprene production.

  13. A bibliography for Quercus garryana and other geographically associated and botanically related oaks.

    Science.gov (United States)

    Constance A. Harrington; Melanie A. Kallas

    2002-01-01

    Interest in Quercus garryana Dougl. ex Hook., commonly known as Oregon white oak or Garry oak, has increased in recent years as scientists, resource managers, and the general public focus attention on a forest type in decline. To aid those interested in learning what has previously been reported on this species, we have compiled a comprehensive bibliography for Q....

  14. Community structures of N2 -fixing bacteria associated with the phyllosphere of a Holm oak forest and their response to drought.

    Science.gov (United States)

    Rico, L; Ogaya, R; Terradas, J; Peñuelas, J

    2014-05-01

    Biological nitrogen (N) fixation is a key pathway in terrestrial ecosystems and is therefore critical for understanding the responses of ecosystems to global environmental changes. The free-living diazotrophic community is distributed along the canopy-to-soil profile, but the ecological significance of epiphyllic N2 fixers, despite their functional relevance, on plant foliar surfaces remains very poorly understood compared with the N2 -fixing community in forest litter and soils. We assessed the community structure of N2 fixers and overall bacteria by genetic fingerprinting (t-RFLP) to explore the seasonal successional patterns of the microbial community in the natural phyllosphere of a Holm oak (Quercus ilex) forest submitted to 12-year field experiment of rain exclusion mimicking the conditions of drought projected for the coming decades. Leaves of Holm oak were analysed in different seasons over a period of 1.5 years. The bacterial community of the phyllosphere did not correspond to the surrounding soil biome in the same area. These analyses provided field evidence for the presence of free-living diazotrophs associated with the tissues of leaves of Holm oak, the dominant tree species of many Mediterranean forests. The results also revealed that the community composition is affected seasonally and inter-annually by the environment, and that the composition shifts in response to climate change. Drought treatment increased the richness of the epiphyllic microbial community, especially during the summer. These changes were associated with higher C:N ratios of leaves observed in response to drought in semiarid areas. This epiphyllic microbiota that can potentially fix N2 extends the capacity of plants to adapt to the environment.

  15. Back to Osborne. Sequential protein extraction and LC-MS analysis for the characterization of the Holm oak seed proteome.

    Science.gov (United States)

    Romero-Rodríguez, M Cristina; Maldonado-Alconada, Ana M; Valledor, Luis; Jorrin-Novo, Jesus V

    2014-01-01

    It is impossible to capture in just one experiment all or most of the total set of protein species that constitute the cell's proteome. Thus, according to our results, and even considering that they depend on the experimental system carried out (plant, yeast, fungi, or bacteria), the best protein extraction protocol yielded less than 20 % of the total amount of proteins, as determined by the Kjeldahl method. For this reason, protein cataloguing and the whole proteome characterization require the use of firstly, fractionation techniques at the cellular, subcellular, protein, or peptide level, and secondly, the use of complementary approaches.Within our current research on Holm oak (Quercus ilex subsp. ballota), we aim to characterize its seed proteome. For that we have optimized an experimental workflow in which the Osborne sequential protein extraction (Osborne, Science 28:417-427, 1908) is combined with downstream electrophoretic protein separation or shotgun MS analysis. In general, it can be used to study any plant seed, as well as to investigate on seed maturation and germination, genotype characterization, allergens identification, food traceability, and substantial equivalence, among others.

  16. Intraspecific Phenotypic Variation and Ecological Genetics of Blue Oak (Quercus douglasii Hook. & Am.)

    Science.gov (United States)

    Kevin J. Rice; Doria R. Gordon; Jeanine L. Hardison; Jeffrey M. Welker

    1991-01-01

    A field experiment was conducted to examine the effects of soil water availability on blue oak (Quercus douglasii) seedling establishment. Acorns were planted either into cleared plots of 0, 10, 20, or 40 cm diameter. The cleared plots were located in two grazed and one ungrazed site. Half of the plots received drip irrigation in a split plot design...

  17. Predicting the height growth of oak species (Quercus) reproduction over a 23-year period following clearcutting

    Science.gov (United States)

    J. Travis Swaim; Daniel C. Dey; Michael R. Saunders; Dale R. Weigel; Christopher D. Thornton; John M. Kabrick; Michael A. Jenkins

    2016-01-01

    We resampled plots from a repeated measures study implemented on the Hoosier National Forest (HNF) in southern Indiana in 1988 to investigate the influence of site and seedling physical attributes on height growth and establishment success of oak species (Quercus spp.) reproduction in stands regenerated by the clearcut method. Before harvest, an...

  18. Interspecific variation in functional traits of oak seedlings (Quercus ilex, Quercus trojana, Quercus virgiliana) grown under artificial drought and fire conditions.

    Science.gov (United States)

    Chiatante, D; Tognetti, R; Scippa, G S; Congiu, T; Baesso, B; Terzaghi, M; Montagnoli, A

    2015-07-01

    To face summer drought and wildfire in Mediterranean-type ecosystems, plants adopt different strategies that involve considerable rearrangements of biomass allocation and physiological activity. This paper analyses morphological and physiological traits in seedlings of three oak species (Quercus ilex, Quercus trojana and Quercus virgiliana) co-occurring under natural conditions. The aim of this study was to evaluate species-specific characteristics and the response of these oak seedlings to drought stress and fire treatment. Seedlings were kept in a growth chamber that mimicked natural environmental conditions. All three species showed a good degree of tolerance to drought and fire treatments. Differences in specific biomass allocation patterns and physiological traits resulted in phenotypic differences between species. In Q. ilex, drought tolerance depended upon adjustment of the allocation pattern. Q. trojana seedlings undergoing mild to severe drought presented a higher photosystem II (PSII) efficiency than control seedlings. Moreover, Q. trojana showed a very large root system, which corresponded to higher soil area exploitation, and bigger leaf midrib vascular bundles than the other two species. Morphological and physiological performances indicated Q. trojana as the most tolerant to drought and fire. These characteristics contribute to a high recruitment potential of Q. trojana seedlings, which might be the reason for the dominance of this species under natural conditions. Drought increase as a result of climate change is expected to favour Q. trojana, leading to an increase in its spatial distribution.

  19. Effects of Northern red oak (Quercus rubra L. and sessile oak (Quercus petraea (Mattusch. Liebl. on the forest soil chemical properties

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    Miltner Stanislav

    2016-09-01

    Full Text Available Northern red oak (Quercus rubra L. is one of the most important introduced tree species in the Czech Republic, occupying about 6,000 ha with ca. 900,000 m3 of the standing volume. The presented study aims to evaluate its soil forming effects on natural oak sites. Soil chemistry of the upper soil layers (F+H, Ah, B horizons was studied in three pairs of stands of both species. In each stand, four bulk samples were taken separately for particular horizons, each consisting of 5 soil-borer cores. The soil characteristics analysed were: pH (active and potential, soil adsorption complex characteristics (content of bases, exchangeable cation capacity, base saturation, exchangeable acidity (exchangeable Al and H, total carbon and nitrogen content, and plant available nutrients content (P, K, Ca, Mg. Total macronutrient content (P, K, Ca, Mg was analysed only in holorganic horizons. Results confirmed acidification effects of red oak on the upper forest soil layers such as decreased pH, base content, base saturation, all nutrient contents in total as well as plant-available form and increased soil exchangeable acidity (exchangeable Al in comparison to the sessile oak stands, especially in holorganic horizons and in the uppermost mineral layer (Ah horizon. Northern red oak can be considered as a slightly site-soil degrading species in the studied sites and environmental conditions in comparison to native oak species.

  20. Foliar symptoms triggered by ozone stress in irrigated holm oaks from the city of Madrid, Spain.

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    Carlos Calderón Guerrero

    Full Text Available BACKGROUND: Despite abatement programs of precursors implemented in many industrialized countries, ozone remains the principal air pollutant throughout the northern hemisphere with background concentrations increasing as a consequence of economic development in former or still emerging countries and present climate change. Some of the highest ozone concentrations are measured in regions with a Mediterranean climate but the effect on the natural vegetation is alleviated by low stomatal uptake and frequent leaf xeromorphy in response to summer drought episodes characteristic of this climate. However, there is a lack of understanding of the respective role of the foliage physiology and leaf xeromorphy on the mechanistic effects of ozone in Mediterranean species. Particularly, evidence about morphological and structural changes in evergreens in response to ozone stress is missing. RESULTS: Our study was started after observing ozone -like injury in foliage of holm oak during the assessment of air pollution mitigation by urban trees throughout the Madrid conurbation. Our objectives were to confirm the diagnosis, investigate the extent of symptoms and analyze the ecological factors contributing to ozone injury, particularly, the site water supply. Symptoms consisted of adaxial and intercostal stippling increasing with leaf age. Underlying stippling, cells in the upper mesophyll showed HR-like reactions typical of ozone stress. The surrounding cells showed further oxidative stress markers. These morphological and micromorphological markers of ozone stress were similar to those recorded in deciduous broadleaved species. However, stippling became obvious already at an AOT40 of 21 ppm•h and was primarily found at irrigated sites. Subsequent analyses showed that irrigated trees had their stomatal conductance increased and leaf life -span reduced whereas the leaf xeromorphy remained unchanged. These findings suggest a central role of water availability

  1. Cork oak (Quercus suber L.) seedlings acclimate to elevated

    OpenAIRE

    2012-01-01

    Leaf gas-exchange, leaf and shoot anatomy, wood density and hydraulic conductivity were investigated in seedlings of Quercus suber L. grown for 15 months either at elevated (700 lmol mol-1) or normal (350 lmol mol-1) ambient atmospheric CO2 concentrations. Plants were grown in greenhouses in a controlled environment: relative humidity 50% (±5), temperature similar to external temperature and natural light conditions. Plants were supplied with nutrients and two water re...

  2. Drought reduced monoterpene emissions from the evergreen Mediterranean oak Quercus ilex: results from a throughfall displacement experiment

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    S. Rambal

    2009-07-01

    Full Text Available The effects of water limitations on the emission of biogenic volatile organic compounds are not well understood. Experimental approaches studying drought effects in natural conditions are still missing. To address this question, a throughfall displacement experiment was set up in a natural forest of Quercus ilex, an evergreen Mediterranean oak emitting monoterpenes. Mature trees were exposed in 2005 and 2006 either to an additional drought, to irrigation or to natural drought (untreated control. In both years, absolute monoterpene emission rates as well as the respective standard factors of the trees exposed to normal and additional drought strongly declined during the drought periods. Monoterpene emissions were lower in year 2006 than in year 2005 (factor 2 due to a more pronounced summer drought period in this respective year. We observed a significant difference between the irrigation and additional drought or control treatment: irrigated trees emitted 82% more monoterpenes during the drought period 2006 than the trees of the other treatments. However, no significant effect on monoterpene emission was observed between normal and additional drought treatments, despite a significant effect on leaf water potential and photochemical efficiency. During the development of drought, monoterpene emissions responded exponentially rather than linearly to decreasing leaf water potential. Emissions rapidly declined when the water potential dropped below −2 MPa and photosynthesis was persistently inhibited. Monoterpene synthase activities measured in vitro showed no clear reduction during the same period. From our results we conclude that drought significantly reduces monoterpene fluxes of Mediterranean Holm oak forest into the atmosphere due to a lack of primary substrates coming from photosynthetic processes.

  3. Rotation planar extraction and rotation planar chromatography of oak (Quercus robur L.) bark.

    Science.gov (United States)

    Vovk, Irena; Simonovska, Breda; Andrensek, Samo; Vuorela, Heikki; Vuorela, Pia

    2003-04-04

    The versatile novel instrument for rotation planar extraction and rotation planar chromatography was exploited for the investigation of oak bark (Quercus robur L.). The same instrument enabled extraction of the bark, analytical proof of (+)-catechin directly in the crude extract and also its fractionation. Additionally, epimeric flavan-3-ols, (+)-catechin and (-)-epicatechin were separated by analytical ultra-micro rotation planar chromatography on cellulose plates with pure water as developing solvent. A comparison of the extraction of oak bark with 80% aqueous methanol by rotation planar extraction and medium pressure solid-liquid extraction was carried out and both techniques were shown to be suitable for the efficient extraction of oak bark. The raw extracts and fractions on thin-layer chromatography showed many compounds that possessed antioxidant activity after spraying with 1,1-diphenyl-2-picrylhydrazyl. Rotation planar fractionation of 840 mg of crude oak bark extract on silica gel gave 6.7 mg of pure (+)-catechin in one run.

  4. Genetic transformation of cork oak (Quercus suber L.) for herbicide resistance.

    Science.gov (United States)

    Alvarez, Rubén; Alvarez, José M; Humara, Jaime M; Revilla, Angeles; Ordás, Ricardo J

    2009-09-01

    The bar gene was introduced into the cork oak genome. Cork oak embryogenic masses were transformed using the Agrobacterium strain AGL1 which carried the plasmid pBINUbiBar. This vector harbours the genes, nptII and bar, the latter under control of the maize ubiquitin promoter. The transgenic embryogenic lines were cryopreserved. Varying activities of phosphinothricin acetyl transferase were detected among the lines, which carried 1-4 copies of the insert. Molecular and biochemical assays confirmed the stability and expression of the transgenes 3 months after thawing the cultures. These results demonstrate genetic engineering of herbicide tolerance in Quercus spp.

  5. Microsatellite markers for northern red oak (Fagaceae: Quercus rubra)

    Science.gov (United States)

    Preston R. Aldrich; Charles H. Michler; Weilin Sun; Jeanne Romero-Severson

    2002-01-01

    We provide primer sequences for 14 (GA)n microsatellite loci developed from northern red oak, an important timber species. We screened loci using two sets of samples. A parent-offspring set included DNA from seven acorns collected from one mother tree along with maternal DNA, to determine that all progeny carried a maternal allele at each locus....

  6. Myxomycetes from the bark of the evergreen oak Quercus ilex

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    Wrigley de Basanta, Diana

    1998-06-01

    Full Text Available The results of 81 moist chamber cultures of bark from living Quercus ilex trees are reponed. A total of 37 taxa are cited, extending the number of species found on this substrate to 55. The presence of Licea deplanata on the Iberian Península is confirmed. Seven new records are included for the province of Madrid. Some data are contributed on species frequency and incubation times.Se presentan los resultados de 81 cultivos en cámara húmeda de corteza de Quercus ilex vivo. Se citan 37 táxones, que amplían a 55 el número de especies de mixomicetes encontrados sobre este sustrato. Se confirma la presencia en la Península Ibérica de Licea deplanata, y se incluyen siete nuevas citas para la provincia de Madrid. Se aportan datos sobre frecuencia de aparición y tiempos de incubación de algunas especies.

  7. Ozone dynamics in a Mediterranean Holm oak forest: comparison among transition periods characterized by different amounts of precipitation

    OpenAIRE

    Flavia Savi; Silvano Fares

    2014-01-01

    Tropospheric ozone (O3) is one of the most toxic compounds for plants in the atmosphere. The large amount of anthropogenic O3 precursors in the urban areas promote O3 formation, thus making Mediterranean forests located in periurban areas particularly vulnerable to this pollutant. O3 flux measurements have been carried out using the Eddy Covariance technique over a Holm oak forest located 25 Km from Rome downtown, inside the Presidential Estate of Castelporziano (Italy).Two transition periods...

  8. Moisture sorption isotherms and thermodynamic properties of Oak wood ( Quercus robur and Quercus canariensis): optimization of the processing parameters

    Science.gov (United States)

    Bahar, Rim; Azzouz, Soufien; Remond, Romain; Ouertani, Sahbi; Elaieb, Mohamed Taher; El Cafci, Mohamed Afif

    2017-05-01

    The aim of this paper was to determine the moisture desorption isotherms and essentials thermodynamic properties of two Oak wood varieties. Desorption isotherms were measured using a static gravimetric method at 50, 60, 70 and 80 °C within the range of 5-90 % relative humidity. The equilibrium moisture content decreased with increasing temperature and decreased with decreasing relative humidity at a constant temperature. The `Thermodynamic' sorption equation was found to be the best for describing the experimental moisture sorption isotherms of woods within the range of temperature and water activity investigated. The Fiber saturation point, deduced from the `Thermodynamic' model parameters, depends on the temperature and varying from 22.6 to 54.4 (% kg water/kg dry matter). Isosteric heat of desorption and differential entropy were calculated by applying Clausius-Clapeyron equation to the desorption data fitted by the `Thermodynamic' model. The isosteric heat of desorption and the differential entropy decreased with increasing moisture content according to an exponential law equation and varying from 2.03 to 31.14 kJ/mol and from 73.98 to 4.34 J/(mol K), respectively. The linear relationship between differential enthalpy and entropy satisfied the enthalpy-entropy compensation theory. The sign of Gibbs free energy was found to be positive (+283 J/mol) and (+97 J/mol) for Quercus robur and Quercus canariensis, respectively. The isokinetic temperature was found to be greater than the harmonic temperature. Based on the enthalpy-entropy compensation theory, it could be concluded that the moisture desorption isotherm of Oak wood is a non-spontaneous and enthalpy-controlled process.

  9. Moisture sorption isotherms and thermodynamic properties of Oak wood (Quercus robur and Quercus canariensis): optimization of the processing parameters

    Science.gov (United States)

    Bahar, Rim; Azzouz, Soufien; Remond, Romain; Ouertani, Sahbi; Elaieb, Mohamed Taher; El Cafci, Mohamed Afif

    2016-09-01

    The aim of this paper was to determine the moisture desorption isotherms and essentials thermodynamic properties of two Oak wood varieties. Desorption isotherms were measured using a static gravimetric method at 50, 60, 70 and 80 °C within the range of 5-90 % relative humidity. The equilibrium moisture content decreased with increasing temperature and decreased with decreasing relative humidity at a constant temperature. The `Thermodynamic' sorption equation was found to be the best for describing the experimental moisture sorption isotherms of woods within the range of temperature and water activity investigated. The Fiber saturation point, deduced from the `Thermodynamic' model parameters, depends on the temperature and varying from 22.6 to 54.4 (% kg water/kg dry matter). Isosteric heat of desorption and differential entropy were calculated by applying Clausius-Clapeyron equation to the desorption data fitted by the `Thermodynamic' model. The isosteric heat of desorption and the differential entropy decreased with increasing moisture content according to an exponential law equation and varying from 2.03 to 31.14 kJ/mol and from 73.98 to 4.34 J/(mol K), respectively. The linear relationship between differential enthalpy and entropy satisfied the enthalpy-entropy compensation theory. The sign of Gibbs free energy was found to be positive (+283 J/mol) and (+97 J/mol) for Quercus robur and Quercus canariensis, respectively. The isokinetic temperature was found to be greater than the harmonic temperature. Based on the enthalpy-entropy compensation theory, it could be concluded that the moisture desorption isotherm of Oak wood is a non-spontaneous and enthalpy-controlled process.

  10. Drought-induced photosynthetic inhibition and autumn recovery in two Mediterranean oak species (Quercus ilex and Quercus suber).

    Science.gov (United States)

    Vaz, M; Pereira, J S; Gazarini, L C; David, T S; David, J S; Rodrigues, A; Maroco, J; Chaves, M M

    2010-08-01

    Responses of leaf water relations and photosynthesis to summer drought and autumn rewetting were studied in two evergreen Mediterranean oak species, Quercus ilex spp. rotundifolia and Quercus suber. The predawn leaf water potential (Ψ(lPD)), stomatal conductance (gs) and photosynthetic rate (A) at ambient conditions were measured seasonally over a 3-year period. We also measured the photosynthetic response to light and to intercellular CO₂ (A/PPFD and A/C(i) response curves) under water stress (summer) and after recovery due to autumn rainfall. Photosynthetic parameters, Vc(max), J(max) and triose phosphate utilization (TPU) rate, were estimated using the Farquhar model. RuBisCo activity, leaf chlorophyll, leaf nitrogen concentration and leaf carbohydrate concentration were also measured. All measurements were performed in the spring leaves of the current year. In both species, the predawn leaf water potential, stomatal conductance and photosynthetic rate peaked in spring, progressively declined throughout the summer and recovered upon autumn rainfall. During the drought period, Q. ilex maintained a higher predawn leaf water potential and stomatal conductance than Q. suber. During this period, we found that photosynthesis was not only limited by stomatal closure, but was also downregulated as a consequence of a decrease in the maximum carboxylation rate (Vc(max)) and the light-saturated rate of photosynthetic electron transport (J(max)) in both species. The Vc(max) and J(max) increased after the first autumnal rains and this increase was related to RuBisCo activity, leaf nitrogen concentration and chlorophyll concentration. In addition, an increase in the TPU rate and in soluble leaf sugar concentration was observed in this period. The results obtained indicate a high resilience of the photosynthetic apparatus to summer drought as well as good recovery in the following autumn rains of these evergreen oak species.

  11. Artificial regeneration of major oak (Quercus) species in the eastern United States - a review of the literature

    Science.gov (United States)

    Daniel C. Dey; Douglass Jacobs; Ken McNabb; Gary W. Miller; V. Baldwin; G. Foster

    2008-01-01

    Although natural regeneration is often the best method for establishing new oak (Quercus spp.) stands, there are increasingly more situations in which high potential for oak regeneration failure dictates the use of artificial regeneration including direct seeding and planting seedlings. Additionally, afforestation planting programs frequently...

  12. Resilience of Sweet Chestnut and Truffle Holm-Oak Rural Forests in Languedoc-Roussillon, France: Roles of Social-Ecological Legacies, Domestication, and Innovations

    Directory of Open Access Journals (Sweden)

    Yildiz Aumeeruddy-Thomas

    2012-06-01

    Full Text Available The Cévennes sweet chestnut (Castanea sativa Mill. forest-orchards and the holm-oak (Quercus ilex L. black truffle (Tuber melanosporum Vittad. associations of the garrigue in Languedoc-Roussillon have suffered a century of decline because of great reductions of rural populations and lack of understanding of the ecological and social dimensions of these rural forests by sectorial public agencies. Levels of tree and forest domestication alternated during historical periods in parallel with statuses of disorganization and reorganization of local social groups. Social-ecological legacies intrinsically linked to trees, forests, and landscape domestication, as well as knowledge, social, and technical practices have been mobilized and provided a basis for knowledge innovations, new domestications, uses, and new institutional networks related to changes in social set-ups. Collective actions emerging from local needs to revive territories in a modern context, cross-scale and reciprocal exchanges of rural and scientific knowledge, as well as institutional changes are interrelated variables that have enabled innovations and have increased resilience of these rural forests. This paper opens new avenues for future research on the interplay between the effects of social-ecological legacies and innovations on the resilience of social-ecological systems.

  13. High Genetic Differentiation among European White Oak Species (Quercus spp. at a Dehydrin Gene

    Directory of Open Access Journals (Sweden)

    Iacob CRĂCIUNESC

    2015-12-01

    Full Text Available Dehydryn genes are involved in plant response to environmental stress and may be useful to examine functional diversity in relation to adaptive variation. Recently, a dehydrin gene (DHN3 was isolated in Quercus petraea and showed little differentiation between populations of the same species in an altitudinal transect. In the present study, inter- and intraspecific differentiation patterns in closely related and interfertile oaks were investigated for the first time at the DHN3 locus. A four-oak-species stand (Quercus frainetto Ten., Q. petraea (Matt. Liebl., Q. pubescens Willd., Q. robur L. and two populations for each of five white oak species (Q. frainetto Ten., Q. petraea (Matt. Liebl., Q. pubescens Willd., Q. robur L. and Q. pedunculiflora K. Koch were analyzed. Three alleles shared by all five oak species were observed. However, only two alleles were present in each population, but with different frequencies according to the species. At population level, all interspecific pairs of populations showed significant differentiation, except for pure Q. robur and Q. pedunculiflora populations. In contrast, no significant differentiation (p > 0.05 was found among conspecific populations. The DHN3 locus proved to be very useful to differentiate Q. frainetto and Q. pubescens from Q. pedunculiflora (FST = 0.914 and 0.660, respectively and Q. robur (FST = 0.858 and 0.633, respectively. As expected, the lowest level of differentiation was detected between the most closely related species, Q. robur and Q. pedunculiflora (FST = 0.020. Our results suggest that DHN3 can be an important genetic marker for differentiating among European white oak species.

  14. Carbon storage in degraded cork oak (Quercus suber forests on flat lowlands in Morocco

    Directory of Open Access Journals (Sweden)

    Oubrahim H

    2016-02-01

    Full Text Available The present study aims to quantify the carbon stored in a degraded cork oak (Quercus suber L. ecosystem in the north west of Morocco, in view of potential management implications. To this end, carbon stocks were evaluated in the first 100 cm of the soil, the cork oak trees, and the understorey species (both above- and belowground. Results show that the total carbon stocks in the cork oak ecosystem ranges from 65 to 237 Mg ha-1 with a mean value of 121 Mg ha-1. The first 100 cm of the soil (including the forest floor represents the largest carbon pool (~51% of the total organic carbon of the ecosystem. Tree biomass (above- and belowground tissues of cork oak represents the second largest pool (47%, whereas the contribution of the understorey is less than 2%. Within the first 100 cm of the soil, over 87% of all the soil organic carbon is situated in the first 40 cm of the soil depth. The amount of carbon stored here ranges from 30 to 110 Mg ha-1and these organic carbon stocks vary considerably with the stand basal area of the cork oak (R2 = 0.82. In practice, the carbon stocks of the different pools considered are strongly correlated with the stand density of the cork oak stands. In the semi-arid forest ecosystems of our study, management prescriptions aiming at increasing the standing biomass of the cork oak should thus considerably contribute, both directly through tree biomass and indirectly through increased soil organic matter, to efficient carbon sequestration.

  15. Dalechampii oak (Quercus dalechampii Ten., an important host plant for folivorous lepidoptera larvae

    Directory of Open Access Journals (Sweden)

    Kulfan, M.

    2013-06-01

    Full Text Available We conducted a structured analysis of lepidoptera larvae taxocenoses living in leaf bearing crowns of Dalechampii oak (Quercus dalechampii Ten. in nine study plots in the Malé Karpaty Mountains (Central Europe. The differences between lepidoptera taxocenoses in individual oak stands were analyzed. A total of 96 species and 2,140 individuals were found. Species abundance peaked in May, while number of species and species diversity reached the highest values from April to May and from April to June, respectively. Abundance showed two notable peaks in flush feeders and in late summer feeders. Lepidoptera taxocenosis in the study plot Horný háj (isolated forest, high density of ants differed significantly from all other taxocenoses according to Sörensen’s index of species similarity, species diversity, analysis of similarity on the basis of permutation and pairwise tests (ANOSIM, seasonal variability of species composition, and NMDS ordination.

  16. Symptoms of the naturalisation of the Turkey oak (Quercus cerris L. in Polish forests

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    Danielewicz Władysław

    2016-09-01

    Full Text Available The Turkey oak (Quercus cerris L., the natural range of which embraces southern Europe and Asia Minor, belongs to trees rarely introduced into Polish forests. Tree stands where it appears, established before the Second World War, can be found in some 20 localities, mostly in the western part of the country. Because this species is capable of a natural renewal in a woodland environment, a research was made to find in what conditions and how far it undergoes spontaneous naturalisation. Three study sites were chosen in the forests of central Wielkopolska. An inventory was made of mature stands of the Turkey oak and its generative renewal. Plant communities in which the young generation of Q. cerris usually appears were characterised. It was found that self-sown seedlings of this species grew at a distance of up to 2,500 m from parent trees. The highest number and the greatest density of specimens of the secondary generation of the Turkey oak were found at ‘Racot’, which is a 100-hectare, mid-field woodland island where mesotrophic habitats predominate and where about 50% of the area is occupied by communities with manmade pine tree stands. At all sites, Q. cerris penetrates primarily this type of deformed phytocoenoses, developing mostly on former farmland. It has become a permanent component of the underbrush and undergrowth in them, and in some places, it also makes up the tree layer. It was observed that in the study area, it penetrated the woodland environment much more effectively than Quercus rubra, considered an invasive species. The expansion of the Turkey oak in several of the examined localities can be regarded as a basic manifestation of its naturalisation in places where there are phytocoenoses with pine stands in broad-leaf forest habitats in the neighbourhood of parent trees.

  17. Climate change effect on Betula (birch) and Quercus (oak) pollen seasons in the United States

    Science.gov (United States)

    Zhang, Yong; Bielory, Leonard; Georgopoulos, Panos G.

    2014-07-01

    Climatic change is expected to affect the spatiotemporal patterns of airborne allergenic pollen, which has been found to act synergistically with common air pollutants, such as ozone, to cause allergic airway disease (AAD). Observed airborne pollen data from six stations from 1994 to 2011 at Fargo (North Dakota), College Station (Texas), Omaha (Nebraska), Pleasanton (California), Cherry Hill and Newark (New Jersey) in the US were studied to examine climate change effects on trends of annual mean and peak value of daily concentrations, annual production, season start, and season length of Betula (birch) and Quercus (oak) pollen. The growing degree hour (GDH) model was used to establish a relationship between start/end dates and differential temperature sums using observed hourly temperatures from surrounding meteorology stations. Optimum GDH models were then combined with meteorological information from the Weather Research and Forecasting (WRF) model, and land use land coverage data from the Biogenic Emissions Land use Database, version 3.1 (BELD3.1), to simulate start dates and season lengths of birch and oak pollen for both past and future years across the contiguous US (CONUS). For most of the studied stations, comparison of mean pollen indices between the periods of 1994-2000 and 2001-2011 showed that birch and oak trees were observed to flower 1-2 weeks earlier; annual mean and peak value of daily pollen concentrations tended to increase by 13.6 %-248 %. The observed pollen season lengths varied for birch and for oak across the different monitoring stations. Optimum initial date, base temperature, and threshold GDH for start date was found to be 1 March, 8 °C, and 1,879 h, respectively, for birch; 1 March, 5 °C, and 4,760 h, respectively, for oak. Simulation results indicated that responses of birch and oak pollen seasons to climate change are expected to vary for different regions.

  18. BVOC emissions from English oak (Quercus robur) and European beech (Fagus sylvatica) along a latitudinal gradient

    Science.gov (United States)

    van Meeningen, Ylva; Schurgers, Guy; Rinnan, Riikka; Holst, Thomas

    2016-11-01

    English oak (Quercus robur) and European beech (Fagus sylvatica) are amongst the most common tree species growing in Europe, influencing the annual biogenic volatile organic compound (BVOC) budget in this region. Studies have shown great variability in the emissions from these tree species, originating from both genetic variability and differences in climatic conditions between study sites. In this study, we examine the emission patterns for English oak and European beech in genetically identical individuals and the potential variation within and between sites. Leaf scale BVOC emissions, net assimilation rates and stomatal conductance were measured at the International Phenological Garden sites of Ljubljana (Slovenia), Grafrath (Germany) and Taastrup (Denmark). Sampling was conducted during three campaigns between May and July 2014. Our results show that English oak mainly emitted isoprene whilst European beech released monoterpenes. The relative contribution of the most emitted compounds from the two species remained stable across latitudes. The contribution of isoprene for English oak from Grafrath and Taastrup ranged between 92 and 97 % of the total BVOC emissions, whilst sabinene and limonene for European beech ranged from 30.5 to 40.5 and 9 to 15 % respectively for all three sites. The relative contribution of isoprene for English oak at Ljubljana was lower (78 %) in comparison to the other sites, most likely caused by frost damage in early spring. The variability in total leaf-level emission rates from the same site was small, whereas there were greater differences between sites. These differences were probably caused by short-term weather events and plant stress. A difference in age did not seem to affect the emission patterns for the selected trees. This study highlights the significance of within-genotypic variation of BVOC emission capacities for English oak and European beech, the influence of climatic variables such as temperature and light on emission

  19. Climate change effect on Betula (birch) and Quercus (oak) pollen seasons in the United States.

    Science.gov (United States)

    Zhang, Yong; Bielory, Leonard; Georgopoulos, Panos G

    2014-07-01

    Climatic change is expected to affect the spatiotemporal patterns of airborne allergenic pollen, which has been found to act synergistically with common air pollutants, such as ozone, to cause allergic airway disease (AAD). Observed airborne pollen data from six stations from 1994 to 2011 at Fargo (North Dakota), College Station (Texas), Omaha (Nebraska), Pleasanton (California), Cherry Hill and Newark (New Jersey) in the US were studied to examine climate change effects on trends of annual mean and peak value of daily concentrations, annual production, season start, and season length of Betula (birch) and Quercus (oak) pollen. The growing degree hour (GDH) model was used to establish a relationship between start/end dates and differential temperature sums using observed hourly temperatures from surrounding meteorology stations. Optimum GDH models were then combined with meteorological information from the Weather Research and Forecasting (WRF) model, and land use land coverage data from the Biogenic Emissions Land use Database, version 3.1 (BELD3.1), to simulate start dates and season lengths of birch and oak pollen for both past and future years across the contiguous US (CONUS). For most of the studied stations, comparison of mean pollen indices between the periods of 1994-2000 and 2001-2011 showed that birch and oak trees were observed to flower 1-2 weeks earlier; annual mean and peak value of daily pollen concentrations tended to increase by 13.6%-248%. The observed pollen season lengths varied for birch and for oak across the different monitoring stations. Optimum initial date, base temperature, and threshold GDH for start date was found to be 1 March, 8 °C, and 1,879 h, respectively, for birch; 1 March, 5 °C, and 4,760 h, respectively, for oak. Simulation results indicated that responses of birch and oak pollen seasons to climate change are expected to vary for different regions.

  20. Interactive effects of O3 exposure on California black oak (Quercus kelloggii Newb.) seedlings with and without N amendment

    Science.gov (United States)

    T. Handley; Nancy Grulke

    2008-01-01

    We examined the short-term separate and combined effects of simulated nitrogen (N) deposition (fertilization) and ozone (O3) exposure on California black oak seedlings (Quercus kelloggii Newb.), an ecologically important tree of the San Bernardino Mountains downwind of Los Angeles. Realistic concentrations of O3...

  1. Indirect effects of precipitation variation on the decomposition process of Mongolian oak (Quercus mongolica) leaf litter

    Institute of Scientific and Technical Information of China (English)

    LI Xuefeng; HAN Shijie; ZHANG Yan

    2007-01-01

    The effect of precipitation variation on the chemistry of Mongolian oak(Quercus mongolica)leaf litters was examined by analyzing litters of Mongolia oak saplings under four precipitation gradients.The decomposing process of these leaf litters in the Mongolian oak dominated forest was assessed using litter bag method.Compared with the litters of the Mongolian oak saplings from the natural precipitation site(A),litters produced by Mongolian oak from the driest precipitation gradient(A450)had significantly higher concentrations of nitrogen(N),phosphorus(P)and potassium(K)while lower acid-insoluble fraction(A/F)concentration.The decomposition study showed that A450 exhibited significantly higher decomposition rate,mineralization rates of N,P and K as well as much shorter N and P net immobilization periods.On the contrary,litters produced by seedlings from wettest gradient(Ass0)showed a totally opposite pattern.Litters from saplings that received comparable precipitation(A650)to those at the natural site(A)had significantly higher N concentration and faster decomposition rate as well as release rates of N,P and K.The mass loss patterns for the four litter types fitted the exponential model and the decay constant(k)can be well predicted by initial AIF/N.During the decomposition period,N concentration was best related to the percentage of mass remaining of the litters with relatively higher AIF concentrations and lower N concentrations,but the percentage of mass remaining of litters with lower AIF concentrations and higher N concentrations correlates strongly with AIF concentration.Our study proved that changes in precipitation significantly altered the litter quality,and therefore indirectly changed the decay process of leaf litters.

  2. The rhizosphere microbiome of burned holm-oak: potential role of the genus Arthrobacter in the recovery of burned soils.

    Science.gov (United States)

    Fernández-González, Antonio J; Martínez-Hidalgo, Pilar; Cobo-Díaz, José F; Villadas, Pablo J; Martínez-Molina, Eustoquio; Toro, Nicolás; Tringe, Susannah G; Fernández-López, Manuel

    2017-07-20

    After a forest wildfire, the microbial communities have a transient alteration in their composition. The role of the soil microbial community in the recovery of an ecosystem following such an event remains poorly understood. Thus, it is necessary to understand the plant-microbe interactions that occur in burned soils. By high-throughput sequencing, we identified the main bacterial taxa of burnt holm-oak rhizosphere, then we obtained an isolate collection of the most abundant genus and its growth promoting activities were characterised. 16S rRNA amplicon sequencing showed that the genus Arthrobacter comprised more than 21% of the total community. 55 Arthrobacter strains were isolated and characterized using RAPDs and sequencing of the almost complete 16S rRNA gene. Our results indicate that isolated Arthrobacter strains present a very high genetic diversity, and they could play an important ecological role in interaction with the host plant by enhancing aerial growth. Most of the selected strains exhibited a great ability to degrade organic polymers in vitro as well as possibly presenting a direct mechanism for plant growth promotion. All the above data suggests that Arthrobacter can be considered as an excellent PGP rhizobacterium that may play an important role in the recovery of burned holm-oak forests.

  3. Pedunculate oak forests (Quercus robur L. survey in the Ticino Regional Park (Italy by remote sensing

    Directory of Open Access Journals (Sweden)

    Rossini M

    2007-01-01

    Full Text Available Pedunculate oak forests (Quercus robur L. in the Ticino Regional Park (Italy show sensible damage conditions due to different environmental stresses: insect attacks, summer drought and air pollution. Knowing whether oaks are healthy or stressed can provide useful information in order to conserve the forest ecosystems and avoid the lost of valuable natural resources. Environmental stresses can affect tree biochemical and structural variables, such as the concentration, composition and efficiency in light harvesting of foliar pigments, and the Leaf Area Index (LAI. Interest in the use of these variables for forest condition assessment has recently increased because they can be indirectly estimated from remote observations at leaf and canopy level. In particular, in this research we found that total chlorophyll (Chl concentration, a biochemical variable related to crown discoloration rate, was the most suitable variable for the detection of pedunculate oak decline in the Ticino Park. A regression analysis between Chl concentration and optical indices computed from hyperspectral MIVIS data was performed in order to estimate Chl concentration from remote observations. The good correlation between field measurements of Chl concentration and MIVIS optical indices allowed the development of a model to map Chl concentration across the Ticino Park forested area. Promising results demonstrated that remotely sensed data can provide an accurate estimation of Chl concentration and indicated the potential of this technique for forest condition monitoring.

  4. Influence of overstory density on ecophysiology of red oak (Quercus rubra) and sugar maple (Acer saccharum) seedlings in central Ontario shelterwoods

    Science.gov (United States)

    William C. Parker; Daniel C. Dey

    2008-01-01

    A field experiment was established in a secondgrowth hardwood forest dominated by red oak (Quercus rubra L.) to examine the effects of shelterwood overstory density on leaf gas exchange and seedling water status of planted red oak, naturally regenerated red oak and sugar maple (Acer saccharum Marsh.) seedlings during the first...

  5. Species-specific climate response of oaks (Quercus spp. under identical environmental conditions

    Directory of Open Access Journals (Sweden)

    Sanders TGM

    2014-04-01

    Full Text Available Oak forests play a major role in Britain due to their economic, social and historic value. Sudden oak death and general decline symptoms have therefore caused major concerns in the forestry sector over the past decade. Several strategies have been proposed to preserve the economic and social value of oak forests, including the planting of native species with more southerly origins, or non-native species of oak that may be better suited to the projected climate of the future. The Ovington research plots, established 50 years ago at the Bedgebury Pinetum in southeast England, provided the opportunity to compare annual growth rates and climate-growth relationships of five oak species growing adjacent to each other on the same soil type and under the same climatic conditions. Clear differences were evident in annual increment and climate-growth responses for the five Quercus species. Growth rates were significantly lower (p<0.05 for the two species native to the UK (Q. petraea and Q. robur compared to the southern European and American species. A partitioning analysis using key climatic variables separates Q. coccinea from the other species due to its negative response to low temperatures. These results were confirmed by pointer year analysis. The analysis suggests that Q. robur is likely to be the more resilient of the two native species of oak to the future climate of southern Britain. Of the non-native species of oak evaluated, Q. coccinea represents an alternative species to Q. robur and Q. petraea on very dry, nutrient-poor sites. Q. palustris may also have some potential under current conditions for species diversification, but its requirement for higher summer precipitation than the other four species suggests that this potential may not be sustained as climate change progresses. However, if alternative species are selected as more resilient to climate change in terms of growth, it will be essential to consider a range of other issues

  6. The macrofungal diversity and community of Atlantic oak (Quercus petraea and Q. robur forests in Ireland

    Directory of Open Access Journals (Sweden)

    Harrington, Thomas J.

    2012-06-01

    Full Text Available The oak species Quercus petraea and Q. Robur are dominant canopy tree species of native deciduous forests in Ireland and coastal regions of Western Europe. These forests are typically plant species-rich, and can also have a rich fungal flora. This survey examined macrofungi found in five native oak sites across Ireland over three years. Overall, 94 macrofungal species belonging to 39 genera were discovered with Mycena, Lactarius, Russula and Cortinarius the most species-rich genera. The species accumulation curve did not show signs of levelling off, indicating that more sampling would reveal more new species. Species richness estimation using the Chao2 estimator indicated that up to 135 species may be present across all of our plots, with individual plots receiving estimates from 19 to 61 species per plot. Sampled-based rarefaction analysis showed no significant differences in macrofungal species richness between our plots. The five most common species were Laccaria amethystina, L. laccata, Stereum hirsutum, Armillaria mellea and Cortinarius flexipes. Comparisons of the results with results from oak forests in similar regions found that the communities in Great Britain were most similar to those found in Ireland. There were some key oak forest distinguishing fungal species from the family Boletaceae lacking from Irish oak forests. It is hypothesised that the historic deforestation of Ireland, caused a reduction of suitable habitats for Irish oak associated macrofungi, leading to the unspecific mycota found in the oak forests of this study. The threats to Atlantic oak forests in Ireland are briefly discussed.Las especies de Quercus petraea y Q. Robur se encuentran en bosques de Irlanda y regiones de influencia atlántica de Europa Occidental. Estos bosques, típicamente ricos en especies de plantas, presentan una abundante micobiota. Este estudio examina la diversidad de macromicetes en cinco bosques naturales de roble en Irlanda durante un

  7. Genetic transformation of selected mature cork oak (Quercus suber L.) trees.

    Science.gov (United States)

    Alvarez, R; Alonso, P; Cortizo, M; Celestino, C; Hernández, I; Toribio, M; Ordás, R J

    2004-10-01

    A transformation system for selected mature cork oak (Quercus suber L.) trees using Agrobacterium tumefaciens has been established. Embryos obtained from recurrent proliferating embryogenic masses were inoculated with A. tumefaciens strains EHA105, LBA4404 or AGL1 harbouring the plasmid pBINUbiGUSint [carrying the neomycin phosphotransferase II (nptII) and beta-glucuronidase (uidA) genes]. The highest transformation efficiency (4%) was obtained when freshly isolated explants were inoculated with A. tumefaciens strain AGL1. Evidence of stable transgene integration was obtained by PCR for the nptII and uidA genes, Southern blotting and expression of the uidA gene. The transgenic embryos were germinated and successfully transferred to soil.

  8. Oak (Quercus Floribunda: A Prominent Indigenous Multipurpose Tree for Carbon Storage and Sequestration Potential

    Directory of Open Access Journals (Sweden)

    K. K. Pandey

    2015-12-01

    Full Text Available A dynamic growth model (CO2FIX has been used for estimating the carbon sequestration potential of Oak (Quercus floribunda, an indigenous multipurpose tree used for timber, fuel wood, fiber and specially fodder in addition to its ability of soil binder. The present study has been carried out in the campus of V.C.S.G. College of Horticulture, U.U.H.F., Bharsar, Pauri Garhwal, Uttarakhand. It is capable of thriving on snow and heavy rainfall condition. CO2FIX was parameterized for a simulation of 100 years respectively. The results indicate that the long term tree biomass accumulated was 120.11 t/ha in above ground and 79.89 t/ha in below ground (Soil Carbon component respectively at the end of simulation period assuming a tree density of 825t/ha (approximately. The net annual carbon sequestration for Oak over the entire simulation period was 1.9 Mg C ha-1 yr -1 (t/ha/yr. Useful for scientific planning and effective implementation of Forestry and Agroforestry developmental programmes at district level as well as at State level for the development of country. For future research work following are few suggestions for better planning and development of State. This type of study can be taken including other parameters/resources such as different trees, different area, and different state and different country as well.

  9. Behavior of pubescent oak (Quercus pubescens Willd. wood to different thermal treatments

    Directory of Open Access Journals (Sweden)

    Todaro L

    2015-12-01

    Full Text Available Quercus pubescens Willd. is a common oak species in the Mediterranean area, where it is currently exploited mainly for purposes such as firewood. To improve the technological properties of its wood, various steaming and/or heat treatments were applied to 160 wood samples from a southern Italian stand, cut from either sapwood or heartwood, while 20 samples served as controls. Steaming was carried out in an autoclave at 120 °C, whereas heat treatments were performed in an oven at 150 or 200 °C for 3 or 6 h. The equilibrium moisture content, swelling, mass loss, wood density, compression strength, color variation, and lignin content of the samples were measured and compared among treatments. The swelling and water adsorption of wood samples decreased due to the hydrothermal treatments. The mass loss was strictly related to the temperature and duration of the heat treatments, whereas it was not influenced by the steaming treatment. The average axial compression strength value was positively influenced by the combination of steaming and heat treatments. A significant and general darkening of color was also observed for the harshest treatments, while an increase of lignin content was detected mainly in the sapwood. Thus, pubescent oak wood subjected to steaming and heat treatments may acquire useful characteristics suitable for its industrial use.

  10. Physiological function of insoluble dietary fiber prepared from exploded oak wood (Quercus mongolica).

    Science.gov (United States)

    Yang, Jae-Kyung; Choi, Myung-Suk; Kim, Chang-Joon; Shin, Yong-Seung; Han, Dae-Yong; Han, Sang-Woo; Lim, Bu-Kug; Lee, Jong-Yoon; Rhee, Soon-Jae; Kim, Eun-Hee; Kim, Gon-Sup

    2006-01-01

    This study investigated the production of insoluble dietary fiber using exploded and chemically treated oak wood (Quercus mongolica) and the physiological functions of prepared insoluble dietary fiber in laboratory animals. To produce high quality insoluble dietary fiber, the steam explosion treatment was performed at 25 kgf/cm2 pressure for 6 minutes. In the chemical analysis of insoluble dietary fiber, exploded oak wood was pretreated by 1% sodium hydroxide solution. The insoluble dietary fiber contained 7.6% residual lignin and 61.7% of alpha-cellulose. In order to compare the physiological functions of prepared insoluble dietary fiber with those of commercial insoluble dietary fiber, Sprague-Dawley male rats weighing 100 +/- 10 g were randomly assigned to one normal diet and five high cholesterol diets, containing 1% cholesterol. The high cholesterol diet groups were classified as the fiber-free diet (FF group), 5% commercial alpha-cellulose diet group (5C group), 10% commercial alpha-cellulose group (10C group), 5% insoluble dietary fiber group (5M group) and 10% insoluble dietary fiber group (10M group). Food intake, weight gain and food efficiency ratio in high cholesterol groups were significantly higher than those of the normal group, but there were no significant differences among the high cholesterol diet groups. In addition, there were no significant differences in the weights of liver, kidney and small intestine in insoluble dietary fiber-supplemented groups. Cecum weights in all insoluble dietary fiber groups were significantly higher than those of the FF group. There were no significant differences in the activities of the glutamic pyruvic transaminase (GPT) and glutamic oxaloacetic transaminase (GOT) among the insoluble dietary fiber-supplemented groups. In conclusion, the prepared insoluble dietary fiber and the commercially available insoluble fiber showed the same physiological effects. Moreover, the preparation method for the insoluble dietary

  11. Physiological Responses to Prolonged Drought Differ Among Three Oak (Quercus) Species

    Science.gov (United States)

    Cooper, C. E.; Moore, G. W.; Vogel, J. G.; Muir, J. P.

    2015-12-01

    The physiological response of plants to water stress provides insights into which species may survive in exceptional drought conditions. This study conducted on a remnant post oak savanna site in College Station, Texas, examined how drought affected the physiology of three native oak species. In June 2014, after a period of equal watering, we subjected three year old Quercus shumardii (Shumard oak; SO), Q. virginiana (live oak; LO), and Q. macrocarpa (bur oak; BO) saplings to one of two watering treatments: 1) watered, receiving the equivalent of theaverage precipitation rate and 2) droughted, receiving a 100% reduction in precipitation. We measured predawn (ΨPD) and midday (ΨMD) leaf water potential; midday gas exchange (MGE) parameters including photosynthesis (Al), transpiration (T), stomatal conductance (gsw); and leaf soluble (SS) and non-soluble sugar (NSS) concentrations monthly between June and October 2014. Drought stress responses were evident after only one month of induced drought. Droughted saplings showed reduced ΨPD, ΨMD, and MGE (P ≤ 0.05) in comparison to watered saplings of the same species. LO saplings exhibited greater MGE (P ≤ 0.05) while maintaining similar LWP to their respective watered and droughted BO and SO counterparts. Droughted LO exhibited MGE rates similar to those of watered BO and SO (P ≤ 0.05), while watered LO adjusted its MGE rates to changes in water availability better than BO and LO during short-term drought. Compared to water saplings, droughted saplings had greater leaf SS (P = 0.08) and lower NSS concentrations (P = 0.10), possibly due to the conversion of NSS to SS and other simple compounds and reduced consumption of SS for growth by the droughted saplings. Although SO and BO exhibited similar photosynthesis rates, leaf total sugar (SS+NSS) concentration was greater in SO (P ≤ 0.05). By displaying the greatest average photosynthesis rate (P ≤ 0.05), LO should have accumulated the greatest amount of carbon

  12. Early markers are present in both embryogenesis pathways from microspores and immature zygotic embryos in cork oak, Quercus suber L

    OpenAIRE

    2014-01-01

    Background: In Quercus suber, cork oak, a Mediterranean forest tree of economic and social interest, rapid production of isogenic lines and clonal propagation of elite genotypes have been achieved by developing in vitro embryogenesis from microspores and zygotic embryos respectively. Despite its high potential in tree breeding strategies, due to their recalcitrancy, the efficiency of embryogenesis in vitro systems in many woody species is still very low since factors responsible for embryogen...

  13. UV light impact on ellagitannins and wood surface colour of European oak ( Quercus petraea and Quercus robur)

    Science.gov (United States)

    Zahri, S.; Belloncle, C.; Charrier, F.; Pardon, P.; Quideau, S.; Charrier, B.

    2007-03-01

    Two European oak species ( Q. petraea and Q. robur) have a high content of phenols which may participate in the alteration of colour upon UV irradiation. To study the photodegradation process of oak surfaces, the two oak species extractives, vescalagin, castalagin, ellagic acid and gallic acid were analysed quantitatively by HPLC before and after UV irradiation. Irradiation time was altered between 3, 24, 72, 96, 120, 144, 192 and 216 h. In parallel, any colour changes of Oak wood surface was followed after 120 h of UV-irradiation by measuring CIELAB parameters (DL*, Da*, Db* and DE*). We observed that 60% of total phenol content of extractives decreased after the maximal exposure time. Our findings also showed that castalagin and gallic acid were destroyed after 216 h and vescalagin and ellagic acid after 72 h. This study proves the photosenibility of oakwood extractives which, supplementary to lignin degradation, would strongly result in the discolouration of oak heartwood.

  14. Effects of cadmium on cork oak (Quercus suber L.) plants grown in hydroponics.

    Science.gov (United States)

    Gogorcena, Yolanda; Larbi, Ajmi; Andaluz, Sofia; Carpena, Ramón O; Abadía, Anunciación; Abadía, Javier

    2011-12-01

    Cork oak (Quercus suber L.) is an autochthonous tree species that is being used for reforestation in heavy-metal-contaminated areas in Spain. A hydroponics experiment was carried out to characterize the effects of Cd on several morphological and physiological parameters in this species, including shoot length, nutrient concentrations and allocation in different organs, leaf pigment concentrations, photosynthetic efficiency, root ferric chelate reductase (FCR) activity and organic acid concentrations in xylem sap. Four different Cd treatments were applied, adding Cd chelated with EDTA or as chloride salt at two different concentrations (10 and 50 µM Cd). After 1 month of Cd treatment, plant growth was significantly inhibited in all treatments. Results indicate that Cd accumulates in all organs 7- to 500-fold when compared with control plants. The highest Cd concentration was found in the 50 µM CdCl(2) treatment, which led to concentrations of ~30, 123 and 1153 µg Cd g(-1) dry weight in leaves, stems and roots, respectively. In the strongest Cd treatments the concentrations of P and Ca decreased in some plant parts, whereas the Mn leaf concentrations decreased with three of the four Cd treatments applied. The concentrations of chlorophyll and carotenoids on an area basis decreased, whereas the (zeaxanthin plus antheraxanthin)/(total violaxanthin cycle carotenoids) ratio and the non-photochemical quenching increased significantly in all Cd treatments. Cadmium treatments caused significant increases in the activity of the enzyme FCR in roots and in the concentrations of organic acids in xylem sap. Some of the physiological changes found support the fact that Cd induces a deficiency of Fe in cork oak, although the plant Fe concentrations were not reduced significantly. At higher concentrations the effects of Cd were more pronounced, and were more marked when Cd was in the free ion form than when present in the form of Cd-EDTA.

  15. Responses and acclimation of Chinese cork oak (Quercus variabilis Bl.) to metal stress: the inducible antimony tolerance in oak trees.

    Science.gov (United States)

    Zhao, Xiulian; Zheng, Lingyu; Xia, Xinli; Yin, Weilun; Lei, Jingpin; Shi, Shengqing; Shi, Xiang; Li, Huiqing; Li, Qinghe; Wei, Yuan; Chang, Ermei; Jiang, Zeping; Liu, Jianfeng

    2015-08-01

    Antimony (Sb) pollution has become a pressing environmental problem in recent years. Trees have been proven to have great potential for the feasible phytomanagement; however, little is known about Sb retention and tolerance in trees. The Chinese cork oak (Quercus variabilis Bl.) is known to be capable of growth in soils containing high concentrations of Sb. This study explored in detail the retention and acclimation of Q. variabilis under moderate and high external Sb levels. Results revealed that Q. variabilis could tolerate and accumulate high Sb (1623.39 mg kg(-1) DW) in roots. Dynamics of Sb retention in leaves, stems, and roots of Q. variabilis were different. Leaf Sb remained at a certain level for several weeks, while in roots and stems, Sb concentrations continued to increase. Sb damaged tree's PSII reaction cores but elicited defense mechanism at the donor side of PSII. It affected the electron transport flow after QA (-) more strongly than the oxygen-evolving complex and light-harvesting pigment-protein complex II. Sb also decreased leaf chlorophyll concentrations and therefore inhibited plant growth. During acclimation to Sb toxicity, Sb concentrations in leaves, stems, and roots decreased, with photosynthetic activity and pigments recovering to normal levels by the end of the experiment. These findings suggest that Sb tolerance in Q. variabilis is inducible. Acclimation seems to be related to homeostasis of Sb in plants. Results of this study can provide useful information for trees breeding and selection of Sb phytomanagement strategies, exploiting the established ability of Q. variabilis to transport, delocalize in the leaves, and tolerate Sb pollutions.

  16. The Occurrence of Charcoal Disease Caused by Biscogniauxia mediterranea on Chestnut-Leaved Oak (Quercus castaneifolia) in the Golestan Forests of Iran

    NARCIS (Netherlands)

    Mirabolfathy, M.; Groenewald, J.Z.; Crous, P.W.

    2011-01-01

    The chestnut-leaved oak (Quercus castaneifolia) is native to the Alborz Mountains, including the Golestan Forests, in northern Iran. Trees grow up to 35 (-50) m tall with a trunk up to 2.5 (-3.5) m in diameter. During 2010, we received reports of a decline of oak trees in the Ghorogh Region of the G

  17. Conservation Strategies for the Threatened Quercus Semecarpifolia Sm. A Himalayan Timberline Oak

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    Hemlata BISHT

    2011-12-01

    Full Text Available Quercus semecarpifolia Sm. is a temperate, timberline, multipurpose oak species. It plays an important role in the Himalayan ecosystem. Human pressure, predation, short-lived acorns, failure of good seed crop every year, poor regeneration, desiccation, frost sensitivity and climate change may lead to complete extinction of the species in a near future. Immediate attention to conservation and restoration measures of the Himalayan ecosystem, in which this species grows, is required. Thus, an experiment was designed to analyze the role of planting stock and micro-sites for the regeneration of Q. semecarpifolia in-situ. For that purpose, 16 microsites with presence/absence of litter, canopy and sunlight were identified, where seeds/propagules were planted. The presence of litter, canopy and sunlight influenced the seedling production, mainly impairing the processes, leading to the expansion in diameter of the radicle, causing shoot/root emergence. Radicle emergence took place in all the seeds immediately after shedding but only 20% of seedlings recovered; however, when the stored seeds were sown as soon as the emerging radicle attained 10-15cm in length and 2-3cm in diameter, 80% of seedlings were recovered. Surprisingly, after being detached from the seed the swollen radicle acted as a propagule and produced 80% seedlings irrespective of the microsites; however, radicles detached prior to diameter expansion failed to produce seedlings which is a crucial insight for promoting seedling production.

  18. Diurnal changes in photoprotective mechanisms in leaves of cork oak (Quercus suber) during summer.

    Science.gov (United States)

    Faria, T.; García-Plazaola, J. I.; Abadía, A.; Cerasoli, S.; Pereira, J. S.; Chaves, M. M.

    1996-01-01

    Daily variations in photoprotective mechanisms were studied in sun and shade leaves of 40-year-old cork oak (Quercus suber L.) trees during early summer in Portugal. Although trees were not severely water stressed because predawn leaf water potentials remained high, photosynthesis and stomatal conductance decreased at midday. The midday depression in gas exchange was not reversed by short-term exposure to "optimal" conditions of temperature, light and vapor pressure deficit. Chlorophyll a fluorescence, maximum photochemical yield of photosystem II and the quantum yield of noncyclic electron transport showed midday depressions, but recovered by the evening. Both short-term changes in the components of the xanthophyll cycle (reversible de-epoxidation of violaxanthin during the day) as well as long-term changes (higher xanthophyll content in sun compared with shade leaves) were detected and may play a role in the dissipation of excess energy at midday. Because the activities of enzymes of the antioxidant system, superoxide dismutase and ascorbate peroxidase, were high enough to cope with the increase in oxygen reactive species likely to arise under the stressful conditions of midday, we conclude that these enzymes may provide an additional mechanism for energy dissipation.

  19. Characterization of the responses of cork oak (Quercus suber) to iron deficiency.

    Science.gov (United States)

    Gogorcena, Y; Molias, N; Larbi, A; Abadía, J; Abadía, A

    2001-12-01

    We studied responses of cork oak (Quercus suber L.) to iron (Fe) deficiency by comparing seedlings grown hydroponically in nutrient solution with and without Fe. Seedlings grown without Fe developed some responses typical of the Strategy I group of Fe-efficient plants, including two- and fourfold increases in plasma membrane ferric chelate reductase activity of root tips after 2 and 4 weeks of culture in the absence of Fe, respectively. Moreover, seedlings grown hydroponically for 2 weeks without Fe caused marked decreases in the pH of the nutrient solution, indicating that root plasma membrane ATPase activity was induced by Fe deficiency. Iron deficiency also caused marked decreases in leaf chlorophyll and carotenoid concentrations, and chlorophyll concentrations were decreased more than carotenoid concentrations. Iron deficiency resulted in an 8% decrease in the dark-adapted efficiency of photosystem II and a 43% decrease in efficiency of photosystem II at steady-state photosynthesis. No major root morphological changes were observed in seedlings grown without Fe, although seedlings grown in Fe-deficient nutrient solution had light-colored roots in contrast to the dark brown color of control roots.

  20. Diurnal and seasonal emissions of volatile organic compounds from cork oak ( Quercus suber) trees

    Science.gov (United States)

    Pio, C. A.; Silva, P. A.; Cerqueira, M. A.; Nunes, T. V.

    The emissions of volatile organic compounds from Quercus suber (cork oak) were investigated at two rural sites in Portugal using a branch enclosure method with subsequent analysis by gas chromatography/flame ionization detection. Q. suber leaves released important amounts of monoterpenes, mainly in the form of limonene, α-pinene, β-pinene and sabinene. However, significant temporal and intraspecific variations in the relative abundance of the dominant compounds were found during this survey. Emissions from Q. suber were strongly dependent on light and temperature, showing a similar behaviour to that of plant species known to be isoprene producers. But, this work also revealed that, although at lower rates, emissions of monoterpenes continued in the dark for several hours. Emission rates were quite well predicted by algorithms based on the Guenther and Tingey equations; correlations of measurements with modelled data were, on average, r2=0.80. A pronounced seasonal variation was recorded for the emissions of monoterpenes. During the 1-yr study period, standard emission rates ranged between a minimum of 0.2 μg g dw-1 h -1, in winter, and a maximum of 20-30 μg g dw-1 h -1, in summer.

  1. Dry deposition and canopy uptake in Mediterranean holm-oak forests estimated with a canopy budget model: A focus on N estimations

    Science.gov (United States)

    Aguillaume, L.; Izquieta-Rojano, S.; García-Gómez, H.; Elustondo, D.; Santamaría, J. M.; Alonso, R.; Avila, A.

    2017-03-01

    Bulk/wet and throughfall fluxes of major compounds were measured from June 2011 to June 2013 at four Mediterranean holm-oak (Quercus ilex) forests in the Iberian Peninsula. Regression analysis between net throughfall fluxes and precipitation indicated that the best defined canopy process was leaching for K+ and uptake for NH4+ at all sites. A more variable response between sites was found for Na+, Ca2+, SO42- and Cl-, which suggests that the interplay of dry deposition, leaching and uptake at the canopy was different depending on site climate and air quality characteristics. A canopy budget model (CBM) was used to try to discriminate between the canopy processes and enable to estimate dry deposition and uptake fluxes at three of the sites that complied with the model specifications. To derive N uptake, an efficiency factor of NH4+vs. NO3- uptake (xNH4) corresponding to moles of NH4+ taken up for each NO3- mol, has to be determined. Up to now, a value of 6 has been proposed for temperate forests, but we lack information for Mediterranean forests. Experimental determination of N absorption on Quercus ilex seedlings in Spain suggests efficiency factors from 1 to 6. Based on these values, a sensitivity analysis for xNH4 was performed and the NH4sbnd N and NO3sbnd N modeled dry deposition was compared with dry deposition estimated with independent methods (inferential modeling and washing of branches). At two sites in NE Spain under a milder Mediterranean climate, the best match was obtained for xNH4 = 6, corroborating results from European temperate forests. Based on this value, total DIN deposition was 12-13 kg N ha-1 y-1 at these sites. However, for a site in central Spain under drier conditions, variation of the NH4+ efficiency factor had little effect on DD estimates (which ranged from 2 to 2.6 kg N ha-1 y-1 with varying xNH4); when added to wet deposition, this produced a total N deposition in the range 2.6-3.4 kg N ha-1 y-1. Dry deposition was the predominant

  2. Point processes statistics of stable isotopes: analysing water uptake patterns in a mixed stand of Aleppo pine and Holm oak

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    Carles Comas

    2015-04-01

    Full Text Available Aim of study: Understanding inter- and intra-specific competition for water is crucial in drought-prone environments. However, little is known about the spatial interdependencies for water uptake among individuals in mixed stands. The aim of this work was to compare water uptake patterns during a drought episode in two common Mediterranean tree species, Quercus ilex L. and Pinus halepensis Mill., using the isotope composition of xylem water (δ18O, δ2H as hydrological marker. Area of study: The study was performed in a mixed stand, sampling a total of 33 oaks and 78 pines (plot area= 888 m2. We tested the hypothesis that both species uptake water differentially along the soil profile, thus showing different levels of tree-to-tree interdependency, depending on whether neighbouring trees belong to one species or the other. Material and Methods: We used pair-correlation functions to study intra-specific point-tree configurations and the bivariate pair correlation function to analyse the inter-specific spatial configuration. Moreover, the isotopic composition of xylem water was analysed as a mark point pattern. Main results: Values for Q. ilex (δ18O = –5.3 ± 0.2‰, δ2H = –54.3 ± 0.7‰ were significantly lower than for P. halepensis (δ18O = –1.2 ± 0.2‰, δ2H = –25.1 ± 0.8‰, pointing to a greater contribution of deeper soil layers for water uptake by Q. ilex. Research highlights: Point-process analyses revealed spatial intra-specific dependencies among neighbouring pines, showing neither oak-oak nor oak-pine interactions. This supports niche segregation for water uptake between the two species.

  3. Antimicrobial and antioxidative enrichment of oak (Quercus robur) bark by rotation planar extraction using ExtraChrom.

    Science.gov (United States)

    Andrensek, Samo; Simonovska, Breda; Vovk, Irena; Fyhrquist, Pia; Vuorela, Heikki; Vuorela, Pia

    2004-04-15

    The multifunctional ExtraChrom instrument was used in the extraction of antimicrobial and radical scavenging components from oak (Quercus robur L.) bark. Milled and sieved oak bark was extracted with 80% (v/v) methanol solution in water on the ExtraChrom instrument using step-gradient in the preparative separation. Extracts were tested using agar diffusion method on Staphylococcus aureus, Enterobacter aerogenes and Candida albicans. Some extracts showed moderate bactericidal, fungicidal, bacteriostatic and fungistatic activity. The composition related to activity of the fractions and extracts was screened simultaneously by thin-layer chromatography (TLC) detected by UV and by spraying the plate with radical scavenging reagent 1,1-diphenyl-2-picrylhydrazyl (DPPH) to detect antioxidant activity. Thus, we could demonstrate the antiradical and antimicrobial activity of oak beneficial in the storage of wine against the oxidation and human microbial exposure.

  4. Removal of acorns of the alien oak Quercus rubra on the ground by scatter-hoarding animals in Belgian forests

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    Merceron, NR.

    2017-01-01

    Full Text Available Description of the subject. Quercus rubra L. is considered an invasive species in several European countries. However, little is known about its dispersal in the introduced range. Objectives. We investigated the significance of animal dispersal of Q. rubra acorns on the ground by vertebrates in its introduced range, and identified the animal species involved. Method. During two consecutive autumns, the removal of acorns from Q. rubra and from a native oak was assessed weekly in forest sites in Belgium. We used automated detection camera traps to identify the animals that removed acorns. Results. Quercus rubra acorns were removed by wood mice (Apodemus sylvaticus L., red squirrels (Sciurus vulgaris L., rats (Rattus sp., and wild boars (Sus scrofa L.. The two former are scatter-hoarding rodents and can be considered potential dispersers. Conclusions. Dispersal of Q. rubra acorns in Western Europe by scatter-hoarding animals may help the species increasingly colonize forest ecosystems.

  5. Light response of hydraulic conductance in bur oak (Quercus macrocarpa) leaves.

    Science.gov (United States)

    Voicu, Mihaela C; Zwiazek, Janusz J; Tyree, Melvin T

    2008-07-01

    A four- to seven-fold enhancement of leaf hydraulic conductance by light has been reported in three temperate tree species. The enhancement occurs in the liquid-flow pathway between the petiole and the site of water evaporation. The enhancement occurs within 1 h, and dissipates in darkness over a period of 1 to 10 h depending on species. Here we report light-induced enhancement of leaf hydraulic conductance in a fourth species, bur oak (Quercus macrocarpa Michx.), the dependence of the effect on light flux and color, its absence in leaves of seedlings, and the impact on the response of leaf vein severance and several metabolic inhibitors. The light response of leaf hydraulic conductance approached saturation at a photosynthetic photon flux of 150 mumol m(-2) s(-1). Hydraulic enhancement was greater in response to blue and green light than to visible radiation of longer wavelengths, although at the same irradiance, the response to white light was greater than to light of any single color. Atrazine (a photosystem II inhibitor), fusicoccin (which stimulates plasma membrane-bound H(+)-ATPase) and HgCl(2) (an aquaporin blocker) reduced the light response of leaf lamina hydraulic conductance. When 2-mercaptoethanol was added following mercury treatment, the light response was totally suppressed. Our results are consistent with the notion that the effect of light on leaf lamina hydraulic conductance is controlled by factors acting outside the leaf veins, possibly through light-induced changes in membrane permeability of either mesophyll or bundle sheath cells, or both.

  6. Influence of pericarp, cotyledon and inhibitory substances on sharp tooth oak (Quercus aliena var. acuteserrata germination.

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    Yan Liu

    Full Text Available In order to explore the mechanism of delayed and uneven germination in sharp tooth oak (Quercus aliena var. acuteserrata (STO, mechanical scarification techniques were used to study STO root and shoot germination and growth. The techniques used were: removing cup scar (RS, removing the pericarp (RP, and cutting off 1/2 (HC and 2/3 (TC cotyledons. Germination percentage and root and shoot length for Chinese cabbage (Beassica pekinensis seeds (CCS were also investigated for CCS cultivated in a Sanyo growth cabinet watered by distilled water and 80% methanol extracts from the acorn embryo, cotyledon and pericarp with concentrations of 1.0 g, 0.8 g, 0.6 g and 0.4 g dry acorn weight per ml methanol. The results showed that the majority of roots and shoots from acorns with RP and HC treatment emerged two weeks earlier, more simultaneously, and their total emergencies were more than 46% and 28% higher, respectively. TC accelerated root and shoot emergence time and root length, but root and shoot germination rate and shoot height had no significant difference from the control. Positive consequences were not observed on all indices of RS treatment. The germination rates of CCS watered by 1.0 g · ml(-1 methanol extracts from the embryo and cotyledon were significantly lower than those from the pericarp, and all concentrations resulted in decreased growth of root and shoot. Methanol extracts from pericarp significantly reduced root length of CCS, but presented little response in germination percentage and shoot length. The inhibitory effect was gradually increased with the increasing concentration of the methanol extract. We conclude that both the mechanical restriction of the pericarp and the presence of germination inhibitors in the embryo, cotyledon and pericarp are the causes for delayed and asynchronous germination of STO acorns.

  7. The Geographic Distribution of a Tropical Montane Bird Is Limited by a Tree: Acorn Woodpeckers (Melanerpes formicivorus) and Colombian Oaks (Quercus humboldtii) in the Northern Andes.

    Science.gov (United States)

    Freeman, Benjamin G; Mason, Nicholas A

    2015-01-01

    Species distributions are limited by a complex array of abiotic and biotic factors. In general, abiotic (climatic) factors are thought to explain species' broad geographic distributions, while biotic factors regulate species' abundance patterns at local scales. We used species distribution models to test the hypothesis that a biotic interaction with a tree, the Colombian oak (Quercus humboldtii), limits the broad-scale distribution of the Acorn Woodpecker (Melanerpes formicivorus) in the Northern Andes of South America. North American populations of Acorn Woodpeckers consume acorns from Quercus oaks and are limited by the presence of Quercus oaks. However, Acorn Woodpeckers in the Northern Andes seldom consume Colombian oak acorns (though may regularly drink sap from oak trees) and have been observed at sites without Colombian oaks, the sole species of Quercus found in South America. We found that climate-only models overpredicted Acorn Woodpecker distribution, suggesting that suitable abiotic conditions (e.g. in northern Ecuador) exist beyond the woodpecker's southern range margin. In contrast, models that incorporate Colombian oak presence outperformed climate-only models and more accurately predicted the location of the Acorn Woodpecker's southern range margin in southern Colombia. These findings support the hypothesis that a biotic interaction with Colombian oaks sets Acorn Woodpecker's broad-scale geographic limit in South America, probably because Acorn Woodpeckers rely on Colombian oaks as a food resource (possibly for the oak's sap rather than for acorns). Although empirical examples of particular plants limiting tropical birds' distributions are scarce, we predict that similar biotic interactions may play an important role in structuring the geographic distributions of many species of tropical montane birds with specialized foraging behavior.

  8. Is cork oak (Quercus suber L. woodland loss driven by eucalyptus plantation? A case-study in southwestern Portugal

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    Costa A

    2014-06-01

    Full Text Available Mediterranean landscapes with open cork oak (Quercus suber L. woodlands have recently experienced drastic changes in southwestern Portugal. Changes in agricultural activities, the traditional driver of the economy in this region, led to new land uses, such as long-term set aside (shrublands and eucalyptus plantations. A study was conducted on the oak woodland landscape dynamics over a 50-year period (from 1958 to 2007 in order to assess the effect of different biophysical conditions on landscape spatial changes, and to identify the resilience of lanscape composition to different disturbances (e.g., socio-economic changes and wildfires. Land use changes over two consecutive periods (1958-1995 and 1995-2007 were inferred by spatial analysis of land cover data (aerial photographs and related to landscape physical attributes (slope and soil type. A transition matrix of four vegetation land-cover classes was obtained, allowing the assessment of the landscape composition changes bewteen the two above periods. Results showed that lansdcape in 1958 was largely occupied by open farmland, with large patches of open oak woodlands on steep slopes surrounding watercourses. Open farmland and shrubland drastically declined from 1958 to 1995, while eucalyptus plantation exhibited a dramatic expansion. Although large areas of cork oak forest turned into eucalyptus plantation, the net loss of oak forest was low and counterbalanced by its increment on former open farmland. The occurrence of a wildfire in 2003 promoted a dramatic decrease in cork oak woodlands, which mostly turned into shrubland. However, shrubland may be considered “safe sites” for ecological succession, ensuring natural cork oak regeneration and the colonisation of neighboring areas.

  9. Tree species richness, diversity, and regeneration status in different oak (Quercus spp. dominated forests of Garhwal Himalaya, India

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    Sushma Singh

    2016-09-01

    Full Text Available Himalayan forests are dominated by different species of oaks (Quercus spp. at different altitudes. These oaks are intimately linked with hill agriculture as they protect soil fertility, watershed, and local biodiversity. They also play an important role in maintaining ecosystem stability. This work was carried out to study the diversity and regeneration status of some oak forests in Garhwal Himalaya, India. A total of 18 tree species belonging to 16 genera and 12 families were reported from the study area. Species richness varied for trees (4–7, saplings (3–10, and seedlings (2–6. Seedling and sapling densities (Ind/ha varied between 1,376 Ind/ha and 9,600 Ind/ha and 167 Ind/ha and 1,296 Ind/ha, respectively. Species diversity varied from 1.27 to 1.86 (trees, from 0.93 to 3.18 (saplings, and from 0.68 to 2.26 (seedlings. Total basal area (m2/ha of trees and saplings was 2.2–87.07 m2/ha and 0.20–2.24 m2/ha, respectively, whereas that of seedlings varied from 299 cm2/ha to 8,177 cm2/ha. Maximum tree species (20–80% had “good” regeneration. Quercus floribunda, the dominant tree species in the study area, showed “poor” regeneration, which is a matter of concern, and therefore, proper management and conservation strategies need to be developed for maintenance and sustainability of this oak species along with other tree species that show poor or no regeneration.

  10. Leaf morphological variability and intraspecific taxonomic units for pedunculate oak and grayish oak (genus Quercus L., series Pedunculatae Schwz.) in Southern Carpathian Region (Romania).

    Science.gov (United States)

    Apostol, Ecaterina Nicoleta; Curtu, Alexandru Lucian; Daia, Liviu Mihai; Apostol, Bogdan; Dinu, Cristiana Georgeta; Şofletea, Neculae

    2017-07-26

    Even though pedunculate oak (Quercus robur L.) and grayish oak (Quercus pedunculiflora K. Koch) have different ecological requirements, they have been considered as having low differentiation at the level of morphological traits and genetic variation. The leaf morphology for 862 trees has been assessed in 16 natural populations, seven of Q. robur, eight of Q. pedunculiflora and a mixed forest were both taxa coexist. In total, fifteen descriptors have been analysed by using discriminant analysis, while it was found that with only four out of the fifteen leaf traits (abaxial pubescence, abaxial colour of the leaf, petiole length and basal shape of lamina) the two taxa could be clearly differentiated. A dendrogram has been constructed on the basis of these traits, where the populations of each taxon have been clustered together. PU and CL traits of Q. pedunculiflora were discussed for their adaptive value for drought resistance in the steppe habitats occupied by this taxon. Using the leaves' morphological descriptors and data from the literature, intra-taxonomic units (varieties, forms and sub-forms) have been identified in all analysed populations. Eight intraspecific units for Q. robur and six for Q. pedunculiflora have been identified in the investigated area. An analysis of spatial distribution of the two taxa and of their intraspecific units has been performed using maps of ecoregions for the study area. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Whole-transcriptome response to water stress in a California endemic oak, Quercus lobata.

    Science.gov (United States)

    Gugger, Paul F; Peñaloza-Ramírez, Juan Manuel; Wright, Jessica W; Sork, Victoria L

    2016-12-21

    Reduced water availability during drought can create major stress for many plant species. Within a species, populations with a history of seasonal drought may have evolved the ability to tolerate drought more than those in areas of high precipitation and low seasonality. In this study, we assessed response to water stress in a California oak species, Quercus lobata Née, by measuring changes in gene expression profiles before and after a simulated drought stress treatment through water deprivation of seedlings in a greenhouse setting. Using whole-transcriptome sequencing from nine samples from three collection localities, we identified which genes are involved in response to drought stress and tested the hypothesis that seedlings sampled from climatically different regions of the species range respond to water stress differently. We observed a surprisingly massive transcriptional response to drought: 35,347 of 68,434 contigs (52%) were differentially expressed before versus after drought treatment, of which 18,111 were down-regulated and 17,236 were up-regulated. Genes functionally associated with abiotic stresses and death were enriched among the up-regulated genes, whereas metabolic and cell part-related genes were enriched among the down-regulated. We found 56 contigs that exhibited significantly different expression responses to the drought treatment among the three populations (treatment × population interaction), suggesting that those genes may be involved in local adaptation to drought stress. These genes have stress response (e.g., WRKY DNA-binding protein 51 and HSP20-like chaperones superfamily protein), metabolic (e.g., phosphoglycerate kinase and protein kinase superfamily protein), transport/transfer (e.g., cationic amino acid transporter 7 and K(+) transporter) and regulatory functions (e.g., WRKY51 and Homeodomain-like transcriptional regulator). Baseline expression levels of 1310 unique contigs also differed among pairs of populations, and they

  12. Using Landsat 8 imagery in detecting cork oak (Quercus suber L. woodlands: a case study in Calabria (Italy

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    Giuseppe Modica

    2016-12-01

    Full Text Available In the Mediterranean basin, cork oak (Quercus suber L. woodlands are characteristic and widespread forestry ecosystems. Though presenting significant economic potential as a renewable resource, they are not adequately valorised, in spite of a growing market demand for cork and cork-based products, which are appreciated, today, for their use in sustainable building. In this respect, cork meets the needs of the building industry in responding to the growing demand for quality products, which are eco- and energy-friendly and hygienically safe. Moreover, European cultural and biodiversity value has been attributed to cork oak woodlands and their most significant examples have been included in the Natura 2000 framework. So far, in some countries like Italy, the territorial distribution and characterisation of cork oak woodlands have not been adequately investigated. This study provides a method for mapping the actual presence of cork oak woodlands and for assessing their potential distribution. Special attention was given to the characterisation of cork oak spectral signature. To this end, Landsat 8 satellite images, digital photointerpretation and in situ surveys were implemented. The work carried out allows assessing the effectiveness of GIS and remote sensing techniques coupled with ancillary data and tools, and their applicability for the development of a comprehensive mapping and monitoring system of cork oak woodlands in Mediterranean ecosystems. Such techniques are vital to develop a detailed management strategy and to assist restoration activities and the economic assessment of semi-natural habitats. A case study, carried out in two different locations in Calabria (Italy, is provided.

  13. Impacts of soil moisture on de-novo monoterpene emissions from European beech, Holm oak, Scots pine, and Norway spruce

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    C. Wu

    2014-09-01

    Full Text Available Impacts of soil moisture on de-novo monoterpene (MT emissions from Holm oak, European beech, Scots pine, and Norway spruce were studied in laboratory experiments. The volumetric water content of the soil, Θ, was used as reference quantity to parameterize the dependency of MT emissions on soil moisture and to characterize the severity of the drought. When Θ dropped from 0.4 m3 m−3 to ~ 0.2 m3 m−3 slight increases of de-novo MT emissions were observed but with further progressing drought the emissions decreased to almost zero. The increases of MT emissions observed under conditions of mild drought were explainable by increases of leaf temperature due to lowered transpirational cooling. When Θ fell below certain thresholds, MT emissions decreased simultaneously with Θ and the relationship between Θ and MT emissions was approximately linear. The thresholds of Θ (0.044–0.19 m3 m−3 were determined as well other parameters required to describe the soil moisture dependence of de-novo MT emissions for application in the Model of Emissions of Gases and Aerosols from Nature, MEGAN. A factorial approach was found appropriate to describe the impacts of Θ, temperature, and light. Temperature and Θ influenced the emissions largely independent from each other, and, in a similar manner, light intensity and Θ acted independently on de-novo MT emissions. The use of Θ as reference quantity in a factorial approach was tenable in predicting constitutive de-novo MT emissions when Θ changed on a time scale of days. Only when soil moisture changed suddenly empirical parameterization with Θ as a reference was unsuccessful.

  14. Drivers of radial growth and carbon isotope discrimination of bur oak (Quercus macrocarpa Michx.) across continental gradients in precipitation, vapour pressure deficit and irradiance

    Science.gov (United States)

    Steven L. Voelker; Frederick C. Meinzer; Barbara Lachenbruch; J. Renee Brooks; Richard P. Guyette

    2014-01-01

    Tree-ring characteristics are commonly used to reconstruct climate variables, but divergence from the assumption of a single biophysical control may reduce the accuracy of these reconstructions. Here, we present data from bur oaks (Quercus macrocarpa Michx.) sampled within and beyond the current species bioclimatic envelope to identify the primary...

  15. Soil properties and understory herbaceous biomass in forests of three species of Quercus in Northeast Portugal

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    Marina Castro

    2014-12-01

    Full Text Available Aim of study: This paper aims to characterize some soil properties within the first 25 cm of the soil profile and the herbaceous biomass in Quercus forests, and the possible relationships between soil properties and understory standing biomass.Area of study: Three monoespecific Quercus forests (Q. suber L., Q. ilex subsp. rotundifolia Lam. and Q. pyrenaica Willd in NE Portugal.Material and methods: During 1999 and 2000 soil properties (pH-KCl, total soil nitrogen (N, soil organic carbon (SOC, C/N ratio, available phosphorus (P, and available potassium (K and herbaceous biomass production of three forest types: Quercus suber L., Quercus ilex subsp. rotundifolia Lam. and Quercus pyrenaica Willd were studied.Main results: The results showed a different pattern of soil fertility (N, SOC, P, K in Quercus forests in NE of Portugal. The C/N ratio and the herbaceous biomass confirmed this pattern. Research highlights: There is a pattern of Quercus sp. distribution that correlates with different soil characteristics by soil characteristics in NE Portugal. Q. pyrenaica ecosystems were found in more favoured areas (mesic conditions; Q. rotundifolia developed in nutrient-poor soils (oligotrophic conditions; and Q. suber were found in intermediate zones.Keywords: fertility; biomass; C/N ratio; cork oak; holm oak; pyrenean oak.

  16. Development of cork oak (Quercus suber L.) seedlings in response to tree shelters and mulching in northwestern Tunisia

    Institute of Scientific and Technical Information of China (English)

    Taher Mechergui; Marta Pardos; Naceur Boussaidi; Brahim Hasnaoui; Douglass F.Jacobs

    2013-01-01

    The need for reforestation in cork oak (Quercus suber L.)areas is challenged by difficulties.Principal among these is herbivory of young plants,vegetative competition,and slow growth rates of cork oak seedlings.We evaluated the early development of cork oak seedlings treated using tree shelters and mulching in northwestern Tunisia.We tested three tree shelter treatments (non-vented,vented,and control) to shield seedlings from animal damage and five mulch types to control competing vegetation (Italian Stone Pine,Lentisk,combination of Italian Stone Pine and Lentisk (organic mulches),gravel (inorganic mulch) and no mulch).At the end of the two-year experiment,sheltered seedlings were 89-99% taller than unsheltered seedlings and had higher numbers and lengths of shoot growth flushes.In contrast,both stem diameter growth and dry weight biomass (from samples extracted after two years)were significantly reduced inside tree shelters.Root-to-shoot ratio was not significantly different in sheltered vs.unsheltered seedlings,suggesting that tree shelters do not adversely affect this parameter.Mulching alone did not favour growth,but could be beneficial when combined with tree shelters.The combination of vented tree shelters and gravel mulch was the most effective treatment for promoting diameter,height and stem volume growth.

  17. Digestion and body weight change in Tuj lambs receiving oak (Quercus hartwissiana) leaves with and without PEG

    Energy Technology Data Exchange (ETDEWEB)

    Yildiz, S. [Department of Physiology, Faculty of Veterinary Sciences, Kafkas University, Kars (Turkey)]. E-mail: yildizsedat@hotmail.com; Kaya, I.; Unal, Y.; Aksu Elmali, D.; Kaya, S.; Oncuer, A. [Department of Animal Nutrition, Faculty of Veterinary Sciences, Kafkas University, Kars (Turkey); Cenesiz, M.; Kaya, M. [Department of Physiology, Faculty of Veterinary Sciences, Kafkas University, Kars (Turkey)

    2005-08-19

    Quercus hartwissiana (oak) leaves are a potential alternative feed resource in the north-east of Turkey. The aim of the current study was to evaluate the effects of two levels (185 and 370 g/day) of dry oak leaves, in the presence (50 or 100 g/kg of dry oak leaves) or absence of polyethylene glycol (PEG 6000), on ruminal fermentation parameters (pH, short-chain fatty acids (SCFA), ammonia nitrogen (NH{sub 3}-N)), microbial nitrogen (N) supply, apparent diet digestibility, N retention, and body weight (BW) change in fat-tailed Tuj lambs (n = 42, initial BW 33.0 {+-} 0.7 kg). The lambs received at random one of the following diets for 60 days (on a dry matter basis, n = 6 per group): (1) control, no oak leaves and no PEG; (2) 185 g oak leaves; (3) 185 g oak leaves + 10 g PEG; (4) 185 g oak leaves + 20 g PEG; (5) 370 g oak leaves; (6) 370 g oak leaves + 20 g PEG; (7) 370 g oak leaves + 40 g PEG. All groups were given 272 g concentrate and varying amounts of hay (a mixture of chopped grass and alfalfa in the ratio 55:45), such that the amount of hay plus oak leaves was equal to 645 g. Ruminal fermentation parameters did not change with treatment (pH 6.50 {+-} 0.02, total SCFA 86.3 {+-} 2.1 mmol/L, NH{sub 3}-N = 207 {+-} 5 mg/L). Total CP digestibility (0.775, 0.714, 0.736, 0.748, 0.663, 0.690, 0.672; S.E.M. = 0.008, P < 0.001, for groups 1-7, respectively) and N retention (7.7, 6.8, 6.7, 7.5, 6.1, 5.8, 5.7 g/day; S.E.M. = 0.19, P < 0.05, for groups 1-7, respectively) were lowest but microbial N supply was highest in 370 g oak leaf group supplemented with PEG (6.51, 7.14, 11.45, 12.23, 9.03, 14.49, 14.39 g/day, S.E.M. = 0.76, P < 0.05, for groups 1-7, respectively). Final BW (32.5 {+-} 0.3 kg) did not differ among treatments (P > 0.05). These data suggest that: (1) PEG addition seems unnecessary as it did not improve CP digestibility, N retention and BW; and (2) Q. hartwissiana leaves may be used to replace at least half of hay in the ration of Tuj lambs without a

  18. Timing of Drought Triggers Distinct Growth Responses in Holm Oak: Implications to Predict Warming-Induced Forest Defoliation and Growth Decline

    Directory of Open Access Journals (Sweden)

    J. Julio Camarero

    2015-05-01

    Full Text Available Droughts negatively impact forests by reducing growth and increasing defoliation leading to forest dieback as the climate becomes warmer and drier. However, the timing and severity of droughts determine how differently or intensively water shortage affects primary (shoot and leaf formation and secondary growth (stem radial growth based on tree-ring widths. We compare the impact of two severe droughts (2005, 2012, showing different climatic characteristics on the growth responses of three Mediterranean holm oak stands in northeastern Spain. We also quantify climate trends and drought severity. Then, we use remote sensing data to infer how those droughts impacted forest productivity. Both droughts were characterized by warm and dry spring conditions leading to reduced budburst, low shoot production, asynchrony in primary growth and decreased productivity and scarce radial growth, particularly in 2005. However, defoliation peaked in 2012 when radial growth showed minimum values and early spring and late summer temperatures reached maximum values. We discuss how uncoupled and resilient are the responses of primary and secondary growth to drought. Finally, these findings are used to gain insight into the drought-related drivers of defoliation in Spanish holm oak forests.

  19. Ozone dynamics in a Mediterranean Holm oak forest: comparison among transition periods characterized by different amounts of precipitation

    Directory of Open Access Journals (Sweden)

    Flavia Savi

    2014-06-01

    Full Text Available Normal 0 14 false false false MicrosoftInternetExplorer4 Tropospheric ozone (O3 is one of the most toxic compounds for plants in the atmosphere. The large amount of anthropogenic O3 precursors in the urban areas promote O3 formation, thus making Mediterranean forests located in periurban areas particularly vulnerable to this pollutant. O3 flux measurements have been carried out using the Eddy Covariance technique over a Holm oak forest located 25 Km from Rome downtown, inside the Presidential Estate of Castelporziano (Italy.Two transition periods - early Spring and late Fall - in two consecutive years were examined. The uncommon low precipitation recorded in both transition periods in 2012 allowed to evaluate the influence of water availability on O3 fluxes during seasons which are not commonly affected by drought stress.Overall, the forest canopy showed to be a net sink of O3, with peak values of mean daily O3 fluxes of -8.9 nmol m-2s-1 at the beginning of flowering season and -4.6 nmol  m-2s-1 at the end of Fall.O3 fluxes were partitioned between stomatal and non stomatal sinks using the evaporative/resistive method based on canopy transpiration in analogy with an Ohm circuit. By comparison of the two years, water availability showed to be an important limiting factor during Spring, since in this season plants are more photosynthetically active and more sensitive to water availability, while in Fall, under conditions of low stomatal conductance,  the dependence on water availability was less appreciated. st1\\:*{behavior:url(#ieooui } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabella normale"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso

  20. Responses to abiotic environmental stresses among phylloplane and soil isolates of Beauveria bassiana from two holm oak ecosystems.

    Science.gov (United States)

    Fernández-Bravo, María; Garrido-Jurado, Inmaculada; Valverde-García, Pablo; Enkerli, Jürg; Quesada-Moraga, Enrique

    2016-11-01

    The response of entomopathogenic mitosporic ascomycete (EMAs) to abiotic stresses might be adapted to the microhabitats in which they inhabit. In phylloplane, these organisms are more exposed to such stresses than they are in soil, which may have led to adaptation to this environment. In the present work, we investigate whether Beauveria bassiana genotype or isolation habitat, i.e., soil or phylloplane, within the same geographic area influences their responses to key environmental stresses, such as temperature, moisture and ultraviolet radiation (UV-B), which can affect their successful use in microbial control. Twenty isolates of B. bassiana obtained from the soil and phylloplane in two ecosystems from southern Spain (holm oak dehesa and a reforested area) were selected to study the population distribution of these isolates and evaluate their thermal, humidity and UV-B requirements. Molecular characterization was conducted by using elongation factor-1α (EF-1α), the intergenic nuclear region Bloc and 15 microsatellite primers. The cluster analysis based on concatenated EF-1α and Bloc sequences grouped the 20 isolates into five clades within B. basiana, with Clades a, b, d and e containing both soil and phylloplane isolates and Clade c including three phylloplane isolates. The dendrogram and the minimal spanning network generated from the genetic distances among multilocus genotypes showed four divergent groups corresponding to the five clades obtained based on the sequence data (Clades b and d were represented in the same group), with a high degree of shared alleles within groups and few alleles shared among groups. Although no relationship was found between MLG and the habitat (soil or phylloplane) of isolation, isolates grouped into Clade c, all of which were collected from phylloplane, formed a separate group of MLGs. To investigate our hypothesis, the responses to temperature (germination and colony growth evaluated in the range 15-35°C), water activity

  1. Conservation and fruit biology of Sichou oak (Quercus sichourensis, Fagaceae – A critically endangered species in China

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    Ke Xia

    2016-10-01

    Full Text Available Several conservation programs have been started for the critically endangered Sichou oak (Quercus sichourensis since 2007. These programs include detailed field investigations, seedling cultivation and research on the fruit biology of the species. In this study, we first report on the five mature individual trees found in our 9-year field investigation. Thus far, a total of 10 mature individuals have been recorded. All Q. sichourensis trees are healthy and most produce healthy acorns. Acorns of Q. sichourensis are large with dry masses of 8.0–14.0 g. These acorns had high moisture contents at collection and died shortly after (7–28 d when dried with silica gel. Characteristics of Q. sichourensis acorns varied between populations. Compared with the acorns from Funing, the acorns collected from Ceheng were bigger, more viable (germination percentage was up to 96%, less sensitive to desiccation, and germinated faster. Q. sichourensis occurs in regions with a distinct 5–6 month dry season. Habitat degradation is largely responsible for the rareness of Quercus sichorensis, but desiccation sensitivity of the acorns may also limit the regeneration of the species and potentially lead to its continued rareness. As a species with extremely small populations (PSESP, Q. sichourensis is facing high risk of extinction and should be defined as a Critically Endangered species in the global IUCN Red List.

  2. Water-use efficiency in cork oak (Quercus suber) is modified by the interaction of water and light availabilities.

    Science.gov (United States)

    Aranda, Ismael; Pardos, Marta; Puértolas, Jaime; Jiménez, Maria Dolores; Pardos, Jose Alberto

    2007-05-01

    We studied the interaction of light and water on water-use efficiency in cork oak (Quercus suber L.) seedlings. One-year-old cork oak seedlings were grown in pots in a factorial experiment with four light treatments (68, 50, 15 and 5% of full sunlight) and two irrigation regimes: well watered (WW) and moderate drought stress (WS). Leaf predawn water potential, which was measured at the end of each of two cycles, did not differ among the light treatments. Water-use efficiency, assessed by carbon isotope composition (delta(13)C), tended to increase with increasing irradiance. The trend was similar in the WW and WS treatments, though with lower delta(13)C in all light treatments in the WW irrigation regime. Specific leaf area increased with decreasing irradiance, and was inversely correlated with delta(13)C. Thus, changes in delta(13)C could be explained in part by light-induced modifications in leaf morphology. The relationship between stomatal conductance to water vapor and net photosynthesis on a leaf area basis confirmed that seedlings in higher irradiances maintained a higher rate of carbon uptake at a particular stomatal conductance, implying that shaded seedlings have a lower water-use efficiency that is unrelated to water availability.

  3. Association between radionuclides ((210)Po and (210)Pb) and antioxidant enzymes in oak (Quercus coccifera) and mastic tree (Pistacia lentiscus).

    Science.gov (United States)

    Uğur Görgün, A; Aslan, E; Kül, M; İlhan, S; Dimlioğlu, G; Bor, M; Özdemir, F

    2016-08-27

    The activity levels of naturally occurring radionuclides Polonium-210 and lead-210 in different subjects including plant species have direct or indirect impact on human beings. High levels of ionising radiation cause oxidative stress and the interaction between antioxidative defense and radionuclides is not well established in plant systems. In this study, we aimed to understand the impact of oxidative stress caused by (210)Po and (210)Pb in two Mediterranean plants; Quercus coccifera and Pistacia lentiscus. We analysed the constitutive and seasonal levels of (210)Po, (210)Pb, lipid peroxidation levels, superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities in the field-collected samples. The highest activity concentrations of (210)Po and (210)Pb were detected in both plants in summer and Q. coccifera had higher levels than that of P. lentiscus. SOD and APX activity trends were different between oak and mastic; as compared to P. lentiscus, Q. coccifera efficiently used the two major components of antioxidative defense. Lipid peroxidation levels were low in both plants in all seasons except that of spring which were in good agreement with high antioxidant enzyme activities. In conclusion, we found that high (210)Po and (210)Pb activity concentrations in oak and mastic did not interfere with their growth and life cycles. The ability of both plants for survival and adaptation to Mediterranean environmental constraints provided an additional advantage for coping radionuclide induced oxidative stress as well.

  4. Specific polyphenols and tannins are associated with defense against insect herbivores in the tropical oak Quercus oleoides.

    Science.gov (United States)

    Moctezuma, Coral; Hammerbacher, Almuth; Heil, Martin; Gershenzon, Jonathan; Méndez-Alonzo, Rodrigo; Oyama, Ken

    2014-05-01

    The role of plant polyphenols as defenses against insect herbivores is controversial. We combined correlative field studies across three geographic regions (Northern Mexico, Southern Mexico, and Costa Rica) with induction experiments under controlled conditions to search for candidate compounds that might play a defensive role in the foliage of the tropical oak, Quercus oleoides. We quantified leaf damage caused by four herbivore guilds (chewers, skeletonizers, leaf miners, and gall forming insects) and analyzed the content of 18 polyphenols (including hydrolyzable tannins, flavan-3-ols, and flavonol glycosides) in the same set of leaves using high performance liquid chromatography and mass spectrometry. Foliar damage ranged from two to eight percent per region, and nearly 90% of all the damage was caused by chewing herbivores. Damage due to chewing herbivores was positively correlated with acutissimin B, catechin, and catechin dimer, and damage by mining herbivores was positively correlated with mongolinin A. By contrast, gall presence was negatively correlated with vescalagin and acutissimin B. By using redundancy analysis, we searched for the combinations of polyphenols that were associated to natural herbivory: the combination of mongolinin A and acutissimin B had the highest association to herbivory. In a common garden experiment with oak saplings, artificial damage increased the content of acutissimin B, mongolinin A, and vescalagin, whereas the content of catechin decreased. Specific polyphenols, either individually or in combination, rather than total polyphenols, were associated with standing leaf damage in this tropical oak. Future studies aimed at understanding the ecological role of polyphenols can use similar correlative studies to identify candidate compounds that could be used individually and in biologically meaningful combinations in tests with herbivores and pathogens.

  5. Volatile compounds and sensorial characterization of wines from four Spanish denominations of origin, aged in Spanish Rebollo (Quercus pyrenaica Willd.) oak wood barrels.

    Science.gov (United States)

    Fernández de Simón, Brígida; Cadahía, Estrella; Sanz, Miriam; Poveda, Pilar; Perez-Magariño, Silvia; Ortega-Heras, Miriam; González-Huerta, Carlos

    2008-10-08

    The evolution of almost 40 oak-related volatile compounds and the sensorial characteristics of red wines from four Spanish denominations of origin (DOs) (Bierzo, Toro, Ribera de Duero, and Rioja) during aging in barrels made of Rebollo oak wood, Quercus pyrenaica, were studied and compared to the same wines aged in American and French oak barrels. Each oak wood added unique and special characteristics to the wine, and in addition, each wine showed a different ability to extract the compounds, which result in these characteristics from the oak wood. In general, wines aged in Q. pyrenaica wood were characterized by high levels of eugenol, guaiacol, and other volatile phenols. In regards to compounds like cis-whiskylactone or maltol, the behavior of this wood is very similar to that of American oaks. When considering phenolic aldehydes and ketones, the levels of these compounds are intermediate between those of French and American woods and depend greatly on the type of wine. The type of oak, on the other hand, does not affect the chromatic characteristics of the wines. In sensory analysis, the biggest differences are found in the olfactory phase. Among the four DOs studied, wine aged in Q. pyrenaica presented the highest notes of wood, with more aromas of roasting, toasting, milky coffee, spices, or wine-wood interactions. The wines aged in barrels made of Q. pyrenaica wood were highly regarded, and preference was shown for them over those same wines when they had been aged in barrels of American or French oak.

  6. Phenology, dichogamy, and floral synchronization in a northern red oak (Quercus Rubra L.) seed orchard

    Science.gov (United States)

    We developed a novel scoring system to assess spring phenology in a northern red oak clonal seed orchard. The system was used to score between 304 and 364 ramets for three reproductive seasons and place clones into early, middle, and late phenology groups. While the absolute number of clones in ea...

  7. Assessment and Management of Oak Coppice Stands (Quercus variabilis) in Shangnan County,Southern Shaanxi Province

    Institute of Scientific and Technical Information of China (English)

    Xiao-lan Wang; Hany El Kateb; Bernhard Felbermeier; Ping-cang Zhang; Reinhard Mosandl

    2012-01-01

    The present study was conducted within the frame of the Sino-German project " Rehabilitation of degraded land ecosystems in the mountainous area of the Southern Shaanxi Province,China".The study deals with the assessment of the potential of oak coppices as well as the evaluation of the socioeconomic conditions in the Shangnan County.The ulimate objective of the study is to provide recommendations on the sustainable management of forest resources,which does not only aim to improve the environmental situation but also to satisfy the demands of the local rural residents.The study was based on 30 samples of oak coppices stands,which were randomly selected within an area of a size of 20 km × 20 km.In each selected stand,the mature stand and understory regeneration were investigated in depth.For the socio-economic survey,175 households from 11 villages were randomly selected.Results revealed that the stocking capacity of the cork oak coppices reaches 120 m3/ha in average at the older age classes (≥25 years) even after frequent timber harvest.High potential for productivity was indicated by the availability of sufficient vigorous individuals at different age classes.In addition,the understory regeneration was sufficient in density (19,000 ± 133 individual/ha) and consisted of diverse valuable nativespecies (17 species within a survey area of 400 m2).The results of the assessment of the oak coppices provided possibilities for some practices that can be recommended towards sustainable management of such stands.On the other hand,results of the socioeconomic study showed a high degree of acceptance among the local inhabitants (79% of the total households)to change traditional land use,providing an enhancement of their economic situation.

  8. Larvicidal activity of oak Quercus infectoria Oliv. (Fagaceae) gall extracts against Anopheles stephensi Liston.

    Science.gov (United States)

    Aivazi, Ali-Ashraf; Vijayan, V A

    2009-06-01

    There is a growing interest in the use of botanical insecticides to reduce the use of synthetic pesticides in order to avoid environmental side effects. Anopheles stephensi is the primary vector of urban malaria, an endemic disease in India. So, an effort to assay An. stephensi larvae with gall extracts of Quercus infectoria was made under laboratory conditions at Mysore. Ethyl-acetate extract was found to be the most effective of all the five extracts tested for larvicidal activity against the fourth instar larvae, with LC(50) of 116.92 ppm followed by gallotannin, n-butanol, acetone, and methanol with LC(50) values of 124.62, 174.76, 299.26, and 364.61 ppm, respectively. The efficacy in killing mosquito larvae may make this plant promising for the development of new botanical larvicide.

  9. Multilevel Nonlinear Mixed-Effect Crown Ratio Models for Individual Trees of Mongolian Oak (Quercus mongolica) in Northeast China.

    Science.gov (United States)

    Fu, Liyong; Zhang, Huiru; Lu, Jun; Zang, Hao; Lou, Minghua; Wang, Guangxing

    2015-01-01

    In this study, an individual tree crown ratio (CR) model was developed with a data set from a total of 3134 Mongolian oak (Quercus mongolica) trees within 112 sample plots allocated in Wangqing Forest Bureau of northeast China. Because of high correlation among the observations taken from the same sampling plots, the random effects at levels of both blocks defined as stands that have different site conditions and plots were taken into account to develop a nested two-level nonlinear mixed-effect model. Various stand and tree characteristics were assessed to explore their contributions to improvement of model prediction. Diameter at breast height, plot dominant tree height and plot dominant tree diameter were found to be significant predictors. Exponential model with plot dominant tree height as a predictor had a stronger ability to account for the heteroskedasticity. When random effects were modeled at block level alone, the correlations among the residuals remained significant. These correlations were successfully reduced when random effects were modeled at both block and plot levels. The random effects from the interaction of blocks and sample plots on tree CR were substantially large. The model that took into account both the block effect and the interaction of blocks and sample plots had higher prediction accuracy than the one with the block effect and population average considered alone. Introducing stand density into the model through dummy variables could further improve its prediction. This implied that the developed method for developing tree CR models of Mongolian oak is promising and can be applied to similar studies for other tree species.

  10. Patterns of stomatal conductance among blue oak (Quercus douglasii) size classes and populations: implications for seedling establishment.

    Science.gov (United States)

    Matzner, Steven L; Rice, Kevin J; Richards, James H

    2003-08-01

    Quercus douglasii Hook. & Arn. (blue oak) is a deciduous white oak that is currently failing to regenerate throughout much of its range in California, USA. Patterns of water use were observed in adult trees, saplings and seedlings to determine if ontogenetic changes in water use occur, which might be important in the establishment of this long-lived perennial species in a Mediterranean-type system. Seasonal and diurnal stomatal conductance (g(s)), late-season predawn xylem water potentials (Psi(pre)), carbon isotopic ratio (delta(13)C) and soil water status were compared among the three size classes at three sites differing in mean precipitation and soil water characteristics. Comparisons were also made between microsites with and without regeneration (defined by the presence or absence of saplings). Overall patterns of water use were consistent among the three sites, except that, at the site with the highest rainfall, Q. douglasii plants had higher g(s) and more positive Psi(pre) values. Although no differences in water use patterns were found between regeneration and non-regeneration microsites, the observed ontogenetic differences in water use may have important implications for Q. douglasii establishment. Compared with adult trees and saplings, seedlings had higher gas exchange rates during periods of high soil water content (early in the season and in the morning). Seedling g(s) was correlated with percent extractable soil water (ESW) throughout the season; adult tree and sapling g(s) was correlated with ESW between June and September. Despite experiencing greater water stress (indicated by more negative Psi(pre) values) than older trees, seedlings had more negative delta(13)C values, implying lower water-use efficiencies.

  11. Early summer drought stress during the first growing year stimulates extra shoot growth in oak seedlings (Quercus petraea

    Directory of Open Access Journals (Sweden)

    Arion eTurcsán

    2016-02-01

    Full Text Available More severe summer droughts are predicted for mid-latitudes in Europe. To evaluate the impact on forest ecosystems and more specifically on forest regeneration, we studied the response to summer drought in oak seedlings (Quercus petraea. Acorns were collected from different mother trees in three stands in Belgium, sown in pots and grown in non-heated greenhouse conditions. We imposed severe drought on the seedlings in early summer by first watering the pots to saturation and then stopping any watering. Weight of the pots and stomatal conductance were regularly measured. Re-watering followed this drought period of five weeks. Height of the seedlings and apical bud development were observed. Stomatal resistance increased towards the end of the experiment in the drought-treated group and was restored after re-watering. The seedlings from the drought treatment displayed a higher probability to produce additional shoot growth after re-watering (p ≤ 0.05. A higher competition for resources (two plants per pot increased this chance. Although this chance was also higher for smaller seedlings, the actual length of the extra growth after re-watering was higher for larger seedlings (p ≤ 0.01. Both in the drought-treated and in the control group the autochthonous provenance growing on a xeric site produced less extra shoots compared to the two other provenances. Finally, stressed plants showed less developed apical buds compared to the control group after re-watering, suggesting a phenological effect on the growth cycle of oaks (p ≤ 0.0001. The higher chance for an extra shoot growth after the drought period can be considered as a compensation for the induced growth arrest during the drought period.

  12. Genome scanning for interspecific differentiation between two closely related oak species [Quercus robur L. and Q. petraea (Matt.) Liebl.].

    Science.gov (United States)

    Scotti-Saintagne, Caroline; Mariette, Stéphanie; Porth, Ilga; Goicoechea, Pablo G; Barreneche, Teresa; Bodénès, Catherine; Burg, Kornel; Kremer, Antoine

    2004-11-01

    Interspecific differentiation values (G(ST)) between two closely related oak species (Quercus petraea and Q. robur) were compiled across different studies with the aim to explore the distribution of differentiation at the genome level. The study was based on a total set of 389 markers (isozymes, AFLPs, SCARs, microsatellites, and SNPs) for which allelic frequencies were estimated in pairs of populations sampled throughout the sympatric distribution of the two species. The overall distribution of G(ST) values followed an L-shaped curve with most markers exhibiting low species differentiation (G(ST) 10% levels. Twelve percent of the loci exhibited significant G(ST) deviations to neutral expectations, suggesting that selection contributed to species divergence. Coding regions expressed higher differentiation than noncoding regions. Among the 389 markers, 158 could be mapped on the 12 linkage groups of the existing Q. robur genetic map. Outlier loci with large G(ST) values were distributed over 9 linkage groups. One cluster of three outlier loci was found within 0.51 cM; but significant autocorrelation of G(ST) was observed at distances <2 cM. The size and distribution of genomic regions involved in species divergence are discussed in reference to hitchhiking effects and disruptive selection.

  13. Low temperature during winter elicits differential responses among populations of the Mediterranean evergreen cork oak (Quercus suber).

    Science.gov (United States)

    Aranda, I; Castro, L; Alía, R; Pardos, J A; Gil, L

    2005-08-01

    Populations of cork oak (Quercus suber L.) were assessed for seasonal and inter-population variability in, and temperature responses of, the ratio between light-induced variable and maximum fluorescence of chlorophyll, Fv/Fm, considered a surrogate for the maximum photochemical efficiency of photosystem II (PSII). Seedlings from 10 populations throughout the distribution range of Q. suber in the Mediterranean basin were grown in a common garden in central Spain. The Fv/Fm ratio of dark-adapted leaves was measured at dawn every month for 2 years. Air temperature was recorded at a nearby climatic station. During the summer, when maximum air temperatures reached 40 degrees C, there were no significant differences in Fv/Fm among populations, but significant differences were seen during the winter. In colder months, Fv/Fm ranged in all populations between 0.5-0.6 and 0.2-0.3 in 2001 and 2002, respectively. The variance explained by the population effect was greatest during winter months, especially in 2002, reaching a peak value of 10% when minimum air temperature was below -10 degrees C. Populations originating from warmer sites showed the largest decline in Fv/Fm between the end of 2001 and the beginning of 2002. Thus, a negative linear relationship was established between mean annual temperature at the population source and population mean Fv/Fm recorded in the coldest month in 2002 and normalized by the Fv/Fm spring measurement.

  14. Sewage sludge effects on mesofauna and cork oak (Quercus suber L.) leaves decomposition in a Mediterranean forest firebreak.

    Science.gov (United States)

    Pernin, Céline; Cortet, Jérôme; Joffre, Richard; Le Petit, Jean; Torre, Franck

    2006-01-01

    Effects of sewage sludge on litter mesofauna communities (Collembola and Acari) and cork oak (Quercus suber L.) leaf litter decomposition have been studied during 18 mo using litterbags in an in situ experimental forest firebreak in southeastern France. The sludge (2.74 t DM ha(-1) yr(-1)) was applied to fertilize and maintain a pasture created on the firebreak. Litterbag colonization had similar dynamics on both the control and fertilized plots and followed a typical Mediterranean pattern showing a greater abundance in spring and autumn and a lower abundance in summer. After 9 mo of litter colonization, Collembola and Acari, but mainly Oribatida, were more abundant on the sludge-fertilized plot. Leaf litter decomposition showed a similar pattern on both plots, but it was faster on the control plot. Furthermore, leaves from the fertilized plot were characterized by greater nitrogen content. Both chemical composition of leaves and sludges and the decomposition state of leaves have significantly affected the mesofauna community composition from each plot.

  15. Diurnal changes in photoprotective mechanisms in leaves of cork oak (Quercus suber) during summer

    Energy Technology Data Exchange (ETDEWEB)

    Faria, T.; Garcia-Plazaola, J. I.; Cerasoli, S.; Pereira, J. S.; Chaves, M. M. [Instituto Superior de Agronomia, Lisbon (Portugal). Dept. de Engenharia Florestal; Abadia, A.

    1996-01-01

    Diurnal variations in photoprotective mechanisms were studied in sun and shade leaves of 40-year old oak trees during early summer in Portugal. Stomatal conductance, and net carbon assimilation rate of sun leaves was found to be highest in the morning, declined substantially by midday and showed almost no recovery in the afternoon, despite the fact that the trees suffered no severe water deprivation as indicated by high predawn leaf water potential. The high positive linear correlation between photosynthesis and stomatal conductance suggests that stomatal closure is a feature of endogenous metabolic regulation rather than a short-term response to light, temperature or leaf-to-air water pressure deficit, and is the main factor limiting photosynthesis under the experimental conditions. 51 refs., 9 figs.

  16. Point processes statistics of stable isotopes: analysing water uptake patterns in a mixed stand of Aleppo pine and Holm oak

    OpenAIRE

    Carles Comas; Jorge del Castillo,; Jordi Voltas; Juan Pedro Ferrio

    2015-01-01

    Aim of study: Understanding inter- and intra-specific competition for water is crucial in drought-prone environments. However, little is known about the spatial interdependencies for water uptake among individuals in mixed stands. The aim of this work was to compare water uptake patterns during a drought episode in two common Mediterranean tree species, Quercus ilex L. and Pinus halepensis Mill., using the isotope composition of xylem water (δ18O, δ2 H) as hydrological marker. ...

  17. Ecophysiological characteristics and cadmium accumulation in Downy Oak (Quercus pubescens Willd.

    Directory of Open Access Journals (Sweden)

    Cocozza C

    2012-10-01

    Full Text Available Heavy metals provoke environmental pollution with potentially toxic effects on human and plants systems. Recently, investigations are conducted on plants that may play a relevant role on pollutants absorption or stabilization, focusing on fast growing tree species in agronomic conditions; little is known on the effects of contaminants on tree species colonizing abandoned fields to be used in restoration ecology. The effects of Cd on photosynthetic performance and metal accumulation were investigated in Quercus pubescens Willd. seedlings grown in pots containing a mixture of sand, clay, turf and Cd-treatments (0, 25 and 75 mg kg-1 dry soil. The studied photosynthetic parameters (Asat= net phytosynthesis; Rday= day respiration; Γcomp= CO2 compensation point; Vcmax= maximum carboxylation rate; Jmax = electron transport rate; TPU = triose phosphate use; Ci/Ca = ratio of intercellular (Ci to ambient (Ca [CO2] (Ci/Ca; Jmax/Vcmax = ratio; (gsmax = maximum stomatal conductance; (lg = stomatal conductance estimated relative to the photosynthetic rate; (Fv/Fm = maximum quantum yield of PSII photochemistry; (ΔF/F’m = effective photochemical efficiency varied progressively with increasing Cd concentration in the soil, highlighting a negative impact on photosynthetic potential and PSII functioning. Approximately 10% of added Cd was found to be extractable from the substrate, at the maximum concentration applied, with about 12 and 0.75 as bioaccumulation and translocation factors, respectively. Analogously, Cd accumulated up to 34, 30 and 46 mg kg−1 in leaves, stem and roots, respectively. While it is not possible to extrapolate from the present study with seedlings to effects on mature pine trees, there are clear implications for regeneration in soils contaminated with heavy metals, which may lead to ecosystem deterioration.

  18. Growth-Climate Response of Young Turkey Oak (Quercus cerris L. Coppice Forest Stands along Longitudinal Gradient in Albania

    Directory of Open Access Journals (Sweden)

    Merita Stafasani

    2015-06-01

    Full Text Available Background and Purpose: Turkey oak (Quercus cerris L. is the most widespread species in Albania and less investigated from dendroclimatological point of view. Previous studies have reported that Q. cerris is sensitive to the environment when growing at different latitudes and ecological conditions. Based on this fact we have explored the response of different Q. cerris populations located along the longitudinal gradient. Materials and Methods: The stem discs were sampled from six sites (Kukes, Diber, Rreshen, Ulez, Elbasan, Belsh along longitudinal gradient ranging from north-east to central Albania. All oak forests stands grow under the influence of specific local Mediterranean climate. Tree-ring widths were measured to the nearest 0.001 mm using a linear table, LINTAB and the TSAP-Win program. Following the standard dendrochronological procedures residual tree-ring width chronologies were built for each site. Statistical parameters commonly used in dendrochronology were calculated for each site chronology. Relations between the tree-ring chronologies were explored using Hierarchical Factor Classification (HFC and Principal Component Analysis (PCA, while the radial growth-climate relationship was analyzed through correlation analysis using a 19-month window from April in the year prior to tree-ring formation (year t - 1 until October in the year of growth (year t. Results and Conclusions: The length of the site chronologies ranged from 16 to 36 years, with the Elbasan site chronology being the longest and the Belsh site chronology the shortest one. Trees at lower elevation were younger than trees at higher elevation. Statistical parameters (mean sensitivity (MS and auto correlation (AC of site chronologies were different among them and lower values of AC1 showed a weaker dependence of radial growth from climatic conditions of the previous growing year. Principal component analysis showed that Belsh, Rreshen and Elbasan site chronologies were

  19. Severe winter rings of oak trees (Quercus robur L.) from Central European Russia.

    Science.gov (United States)

    Khasanov, B F

    2013-11-01

    Oak trees were sampled in a flood plain forest in the valley of the Zapadnaya Dvina (Daugava) river (Tver region, Russia). Annual rings of the time period from 1826 to 2010 were studied. Anatomically distinct rings with a stripe of small-sized cells in the innermost part and narrow earlywood vessels located in three to four rows occurred in 1861, 1862, 1929, 1940, 1942, 1956 and 1979. Deviations of earlywood development were associated with the drop of winter temperature below -42 °C. The percentage of severe winter ring (SWR) occurrence depends upon tree age and decreases from 75.6 % in younger specimens (under 41 years old at the time of the severe winter) to 27.1 % in middle-aged ones (from 41 to 80 years) to 3.5 % in trees older than 80 years. Described anatomical features can be used in the reconstruction of severe winter frequency in the past.

  20. Tree ring growth by core sampling at the CONECOFOR Permanent Monitoring Plots. The deciduous oak (Quercus cerris L. type

    Directory of Open Access Journals (Sweden)

    Maria Chiara MANETTI

    2002-09-01

    Full Text Available Radial growth analysis evaluates the ability of trees to grow under different site and environmental conditions, thus contributing to bio-ecological studies aimed at increasing understanding of forest stand evolution. Tree ring growth is analysed in five Permanent Monitoring Plots (PMPs dominated by Turkey oak (Quercus cerris L.. Common structural features of these PMPs are their origin (coppice forest and their current physiognomy as stored coppice and transitory crop. A dendroecological approach was used to analyse past radial stem growth, the influence of silvicultural background and stand age, as well as to compare the growth rhythm of stands in different site-indexes and environmental conditions. Tree coring was carried out at the time of the first inventory (winter 1996/97 by sampling 8 to 11 dominant and co-dominant trees representative of the upper storey in the buffer area of each PMP. The basic stem and crown growth variables were measured for each tree sampled and two cores collected at 1.30 m. Annual ring width was determined by the Tree Ring Measurement System SMIL3 and the data were elaborated by the ANAFUS software. Site mean curves and growth trend per social class in each stand were defined both by visual comparison and statistical analysis among individual tree series. The main results were as follows: i social differentiation becomes established earlier with better site indexes and higher tree densities; ii sensitivity to external disturbances is higher and more defined in the dominant class than in the co-dominant tree layer; iii competition cycles are clearly discernible and related to both stand density and site-index in young stands under natural evolution (stored coppices; iv when silvicultural interventions were performed in the past is quite visible readable in the stands under conversion into high forest (transitory crops; v the mean series per site are statistically related and common periods characterized by a

  1. The taxonomy of the Japanese oak red scale insect, Kuwania quercus (Kuwana) (Hemiptera: Coccoidea: Kuwaniidae), with a generic diagnosis, a key to species and description of a new species from California.

    Science.gov (United States)

    San'An, Wu; Nan, Nan; Gullan, Penny; Deng, Jun

    2013-01-01

    The oak red scale insect, Kuwania quercus (Kuwana), was described from specimens collected from the bark of oak trees (Quercus species) in Japan. More recently, the species has been identified from California and China, but Californian specimens differ morphologically from Japanese material and are considered here to be a new species based on both morphological and molecular data. In this paper, an illustrated redescription of K. quercus is provided based on type specimens consisting of adult females, first-instar nymphs and intermediate-stage females, and a lectotype is designated for Sasakia quercus Kuwana. The new Californian species, Kuwania raygilli Wu & Gullan, is described and illustrated based on the adult female, first-instar nymph and intermediate-stage female. A new generic diagnosis for Kuwania Cockerell based on adult females and first-instar nymphs, and a key to species based on adult females are included.

  2. Scale-dependent segregation of seeders and resprouters in cork oak (Quercus suber) forests.

    Science.gov (United States)

    Coca, M; Pausas, J G

    2012-02-01

    Recent studies showed that disturbances and water availability determine the richness among plants with different post-fire strategies of Mediterranean-type ecosystems. The aim of this study was to determine whether or not the scale of analysis has an influence on the effects of these factors and, therefore, on the segregation of the dominant post-fire strategies, obligate seeders and obligate resprouters, and facultative species. We recorded all woody species and geographical features on 94 (75 m(2)) plots of cork oak woodlands in the southern Iberian Peninsula. For each regenerative type (resprouters, seeders and species with both traits--facultative species), we tested the relationship between the number of species and the predictors using a generalised linear mixed model. The fixed predictor considered at the large scale was altitude, and fixed predictors considered at the local scale were aspect (north/south) and disturbance (fire and clearing by heavy machinery; yes/no). The random predictor was the factor of site. When this factor did not have significant effect for some regenerative types, these relationships was tested using a generalised linear model. Resprouting species were most represented at lower altitudes and in undisturbed sites, while seeders were also at lower altitudes but mostly on south-facing slopes, especially south-facing disturbed sites. For facultative species, site is the most important variable. The proportion of seeders from the total species is not related to altitude, but it is related to disturbance and aspect. These results suggest that there is no segregation of the richness of seeders and resprouters at the large scale (altitudinal gradient). Differences appeared at the local scale (aspect and disturbance).

  3. Differences in fine-scale genetic structure and dispersal in Quercus ilex L. and Q. suber L.: consequences for regeneration of mediterranean open woods.

    Science.gov (United States)

    Soto, A; Lorenzo, Z; Gil, L

    2007-12-01

    Cork oak (Quercus suber L.) and holm oak (Q. ilex L.) are among the most important tree species (economically and ecologically) in the Western Mediterranean region, where they define unique open woods (created and maintained by man) known as 'dehesas' in Spain. However, these formations are under increasing threat due to the lack of regeneration. We have analysed spatial genetic structure in a mixed parkland; inferences about gene dispersal have also been performed, according to the isolation by distance model. Noticeable differences have been detected between the species, despite their similar ecological roles. Restricted effective dispersal leads to kin structures in cork oak, up to 70 m, while no genetic structure is observed in holm oak. Our results suggest a very effective dispersal for the latter, with a local historical gene flow estimated between 55 and 95 m. This is the first time regeneration of Mediterranean oak parklands has been assessed from a genetic perspective. Effective gene flow detected for holm oaks allows us to discount the risk of inbreeding over successive generations. Thus, regeneration of Q. ilex dehesas will just require action directed to help the settlement of the saplings (such as limiting grazing). However, in those cases where densities are too low, more intense forestation (such as plantation and/or establishment of appropriate shelter) will be needed. The 'density threshold' for initiating regeneration will probably be higher for cork oak, due to its more limited dispersal and minor full-light tolerance.

  4. Modeling of biomass fractionation in a lab-scale biorefinery: Solubilization of hemicellulose and cellulose from holm oak wood using subcritical water.

    Science.gov (United States)

    Cabeza, A; Piqueras, C M; Sobrón, F; García-Serna, J

    2016-01-01

    Lignocellulose fractionation is a key biorefinery process that need to be understood. In this work, a comprehensive study on hydrothermal-fractionation of holm oak in a semi-continuous system was conducted. The aim was to develop a physicochemical model in order to reproduce the role of temperature and water flow over the products composition. The experiments involved two sets: at constant flow (6mL/min) and two different ranges of temperature (140-180 and 240-280°C) and at a constant temperature range (180-260°C) and different flows: 11.0, 15.0 and 27.9mL/min. From the results, temperature has main influence and flow effect was observed only if soluble compounds were produced. The kinetic model was validated against experimental data, reproducing the total organic carbon profile (e.g. deviation of 33%) and the physicochemical phenomena observed in the process. In the model, it was also considered the variations of molecular weight of each biopolymer, successfully reproducing the biomass cleaving.

  5. Variation of Oriental Oak (Quercus variabilis Leaf δ13C across Temperate and Subtropical China: Spatial Patterns and Sensitivity to Precipitation

    Directory of Open Access Journals (Sweden)

    Baoming Du

    2015-06-01

    Full Text Available The concentration of the carbon-13 isotope (leaf δ13C in leaves is negatively correlated with the mean annual precipitation (MAP atlarge geographical scales. In this paper, we explain the spatial pattern of leaf δ13C variation for deciduous oriental oak (Quercus variabilis Bl. across temperate and subtropical biomes and its sensitivity to climate factors such as MAP. There was a 6‰ variation in the leaf δ13C values of oak with a significant positive correlation with latitude and negative correlations with the mean annual temperature (MAT and MAP. There was no correlation between leaf δ13C and altitude or longitude. Stepwise multiple regression analyses showed that leaf δ13C decreased 0.3‰ per 100 mm increase in MAP. MAP alone could account for 68% of the observed variation in leaf δ13C. These results can be used to improve predictions for plant responses to climate change and particularly lower rainfall.

  6. Population-Level Differentiation in Growth Rates and Leaf Traits in Seedlings of the Neotropical Live Oak Quercus oleoides Grown under Natural and Manipulated Precipitation Regimes

    Directory of Open Access Journals (Sweden)

    Jose A. Ramírez-Valiente

    2017-05-01

    Full Text Available Widely distributed species are normally subjected to spatial heterogeneity in environmental conditions. In sessile organisms like plants, adaptive evolution and phenotypic plasticity of key functional traits are the main mechanisms through which species can respond to environmental heterogeneity and climate change. While extended research has been carried out in temperate species in this regard, there is still limited knowledge as to how species from seasonally-dry tropical climates respond to spatial and temporal variation in environmental conditions. In fact, studies of intraspecific genetically-based differences in functional traits are still largely unknown and studies in these ecosystems have largely focused on in situ comparisons where environmental and genetic effects cannot be differentiated. In this study, we tested for ecotypic differentiation and phenotypic plasticity in leaf economics spectrum (LES traits, water use efficiency and growth rates under natural and manipulated precipitation regimes in a common garden experiment where seedlings of eight populations of the neotropical live oak Quercus oleoides were established. We also examined the extent to which intraspecific trait variation was associated with plant performance under different water availability. Similar to interspecific patterns among seasonally-dry tropical tree species, live oak populations with long and severe dry seasons had higher leaf nitrogen content and growth rates than mesic populations, which is consistent with a “fast” resource-acquisition strategy aimed to maximize carbon uptake during the wet season. Specific leaf area (SLA was the best predictor of plant performance, but contrary to expectations, it was negatively associated with relative and absolute growth rates. This observation was partially explained by the negative association between SLA and area-based photosynthetic rates, which is contrary to LES expectations but similar to other recent

  7. Population-Level Differentiation in Growth Rates and Leaf Traits in Seedlings of the Neotropical Live Oak Quercus oleoides Grown under Natural and Manipulated Precipitation Regimes.

    Science.gov (United States)

    Ramírez-Valiente, Jose A; Center, Alyson; Sparks, Jed P; Sparks, Kimberlee L; Etterson, Julie R; Longwell, Timothy; Pilz, George; Cavender-Bares, Jeannine

    2017-01-01

    Widely distributed species are normally subjected to spatial heterogeneity in environmental conditions. In sessile organisms like plants, adaptive evolution and phenotypic plasticity of key functional traits are the main mechanisms through which species can respond to environmental heterogeneity and climate change. While extended research has been carried out in temperate species in this regard, there is still limited knowledge as to how species from seasonally-dry tropical climates respond to spatial and temporal variation in environmental conditions. In fact, studies of intraspecific genetically-based differences in functional traits are still largely unknown and studies in these ecosystems have largely focused on in situ comparisons where environmental and genetic effects cannot be differentiated. In this study, we tested for ecotypic differentiation and phenotypic plasticity in leaf economics spectrum (LES) traits, water use efficiency and growth rates under natural and manipulated precipitation regimes in a common garden experiment where seedlings of eight populations of the neotropical live oak Quercus oleoides were established. We also examined the extent to which intraspecific trait variation was associated with plant performance under different water availability. Similar to interspecific patterns among seasonally-dry tropical tree species, live oak populations with long and severe dry seasons had higher leaf nitrogen content and growth rates than mesic populations, which is consistent with a "fast" resource-acquisition strategy aimed to maximize carbon uptake during the wet season. Specific leaf area (SLA) was the best predictor of plant performance, but contrary to expectations, it was negatively associated with relative and absolute growth rates. This observation was partially explained by the negative association between SLA and area-based photosynthetic rates, which is contrary to LES expectations but similar to other recent intraspecific studies on

  8. Contrasting nuclear and cytoplasmic exchanges between phylogenetically distant oak species (Quercus suber L. and Q. ilex L.) in Southern France: inferring crosses and dynamics.

    Science.gov (United States)

    Mir, C; Jarne, P; Sarda, V; Bonin, A; Lumaret, R

    2009-03-01

    Gene flow is particularly frequent in the genus Quercus (oaks), especially between closely related species. We focus here on Quercus ilex and the cork-producing Quercus suber, which occasionally hybridize although they are phylogenetically markedly separated. Morphological observations were combined with both allozymic and chloroplastic diagnostic markers to characterize hybridization and introgression and to infer their dynamics in two French regions (French Catalonia and Provence), which are separated by several hundred kilometres. Some hybrids were found in both regions, indicating recent hybridization events. As expected from previous studies, most hybrids resulted from female symbol Q. ilex x male symbol Q. suber crosses, but our data showed that the reciprocal cross is also possible. Partial independence between nuclear and chloroplastic introgression was observed in the two species. Nuclear introgression was limited in both species and both regions, with no preferred direction. In Provence, chloroplastic introgression was very rare in both species. Conversely, all Q. suber individuals from French Catalonia were introgressed by Q. ilex chlorotypes. This might be explained by introgression in the Iberian Peninsula antedating the first occurrence of the two species in French Catalonia. We also observed a new chlorotype that was created locally, and was exchanged between the two species. However, the two species still remain genetically differentiated. The dynamics and complexity of exchanges and the factors determining them (including human management of Q. suber) are discussed.

  9. Effects of Visual Grading on Northern Red Oak (Quercus rubra L. Seedlings Planted in Two Shelterwood Stands on the Cumberland Plateau of Tennessee, USA

    Directory of Open Access Journals (Sweden)

    Stacy L. Clark

    2015-10-01

    Full Text Available Artificial regeneration of oak has been generally unsuccessful in maintaining the oak component in productive upland forests of eastern North America. We tested visual grading effects on quality-grown northern red oak (Quercus rubra seedlings planted in two submesic stands on the Cumberland Plateau escarpment of Tennessee, USA. Seedlings were grown for one year using advanced fertilization and irrigation protocols to increase overall size of seedlings, but large variability in size was still evident. Seedlings were divided into two grades prior to planting. The “standard” grade represented seedlings that had undergone a light culling, and the “premium” grade represented the highest quality seedlings. Seven years after planting in a midstory-removal stand, 50 percent of trees survived, growth was negligible, and seedling grade had no effect on survival and yearly growth. In a shelterwood harvest stand, premium grade seedlings had taller height and larger basal diameter (BD (241 cm and 29.5 mm, respectively compared to standard seedlings (201 cm and 25.9 mm, respectively, and a two-year height growth advantage was achieved by planting premium grade compared to standard grade seedlings. Competitive ability and planting shock were similar between grades, and we postulate that an exceptional drought and large size variability in both grades equalized response. While our findings should be confirmed through additional testing, they suggest currently accepted seedling quality standards for northern red oak should be refined to improve regeneration efforts on productive sites in the eastern United States.

  10. Sherlock Holmes

    OpenAIRE

    Fiddler, Michael

    2017-01-01

    Sir Arthur Conan Doyles' Sherlock Holmes 'canon' consists of 56 short stories and 4 novels published between 1887 and 1927. Holmes first appeared in A Study in Scarlet in 1887 in Beeton's Christmas Annual. Doyle killed off the character in The Adventure of the Final Problem in December 1893. Doyle returned to Holmes in the serialised (1901-2) The Hound of the Baskervilles, which was set before the character's death. Lucrative offers from the Strand Magazine in the UK and Collier's Weekly in t...

  11. Sherlock Holmes

    OpenAIRE

    Fiddler, Michael

    2017-01-01

    Sir Arthur Conan Doyles' Sherlock Holmes 'canon' consists of 56 short stories and 4 novels published between 1887 and 1927. Holmes first appeared in A Study in Scarlet in 1887 in Beeton's Christmas Annual. Doyle killed off the character in The Adventure of the Final Problem in December 1893. Doyle returned to Holmes in the serialised (1901-2) The Hound of the Baskervilles, which was set before the character's death. Lucrative offers from the Strand Magazine in the UK and Collier's Weekly in t...

  12. Chloroplast DNA analysis of Tunisian cork oak populations (Quercus suber L.): sequence variations and molecular evolution of the trnL (UAA)-trnF (GAA) region.

    Science.gov (United States)

    Abdessamad, A; Baraket, G; Sakka, H; Ammari, Y; Ksontini, M; Hannachi, A Salhi

    2016-10-24

    Sequences of the trnL-trnF spacer and combined trnL-trnF region in chloroplast DNA of cork oak (Quercus suber L.) were analyzed to detect polymorphisms and to elucidate molecular evolution and demographic history. The aligned sequences varied in length and nucleotide composition. The overall ratio of transition/transversion (ti/tv) of 0.724 for the intergenic spacer and 0.258 for the pooled sequences were estimated, and indicated that transversions are more frequent than transitions. The molecular evolution and demographic history of Q. suber were investigated. Neutrality tests (Tajima's D and Fu and Li) ruled out the null hypothesis of a strictly neutral model, and Fu's Fs and Ramos-Onsins and Rozas' R2 confirmed the recent expansion of cork oak trees, validating its persistency in North Africa since the last glaciation during the Quaternary. The observed uni-modal mismatch distribution and the Harpending's raggedness index confirmed the demographic history model for cork oak. A phylogenetic dendrogram showed that the distribution of Q. suber trees occurs independently of geographical origin, the relief of the population site, and the bioclimatic stages. The molecular history and cytoplasmic diversity suggest that in situ and ex situ conservation strategies can be recommended for preserving landscape value and facing predictable future climatic changes.

  13. Effects of Different Levels of Raw and Processed Oak Acorn (Quercus castaneifolia on Performance, Small Intestine Morphology, Ileal Digestibility of Nutrients, Carcass Characteristics and Some Blood Parameters in Broiler Chickens

    Directory of Open Access Journals (Sweden)

    Rezaie M

    2016-12-01

    Full Text Available This study was conducted to determine the effect of oak acorn (Quercus castaneifolia on performance, small intestine morphology, ileal digestibility of nutrient, carcass and some blood parameters in broiler chicks. A total of fifty hundred four one-d old male chickens (Ross308 strain with seven treatments and four replicates in each treatment were used. Experimental diets were: control (corn-soybean meal diet, raw oak acorn at the levels of 10 and 20 percent, soaked oak acorn diet containing 10 and 20 percent oak acorn soaked in water for 24h., diets contain 10 and 20 percent of soaked oak acorn soaked in water for 48h with twice water substitution. Experiment lasted from 1 to 42 day of ages. Results showed that body weight, weight gain, feed intake, feed conversion ratio, ileal dry matter and protein digestibility, and small intestine morphology was significantly (P

  14. Gross primary production dynamics assessment of a mediterranean holm oak forest by remote sensing time series analysis

    Science.gov (United States)

    Cicuéndez, Víctor; Huesca, Margarita; Rodriguez-Rastrero, Manuel; Litago, Javier; Recuero, Laura; Merino de Miguel, Silvia; Palacios Orueta, Alicia

    2014-05-01

    Agroforestry ecosystems have a significant social, economic and environmental impact on the development of many regions of the world. In the Iberian Peninsula the agroforestry oak forest called "Dehesa" or "Montado" is considered as the extreme case of transformation of a Mediterranean forest by the management of human to provide a wide range of natural resources. The high variability of the Mediterranean climate and the different extensive management practices which human realized on the Dehesa result in a high spatial and temporal dynamics of the ecosystem. This leads to a complex pattern in CO2 exchange between the atmosphere and the ecosystem, i.e. in ecosystem's production. Thus, it is essential to assess Dehesa's carbon cycle to reach maximum economic benefits ensuring environmental sustainability. In this sense, the availability of high frequency Remote Sensing (RS) time series allows the assessment of ecosystem evolution at different temporal and spatial scales. Extensive research has been conducted to estimate production from RS data in different ecosystems. However, there are few studies on the Dehesa type ecosystems, probably due to their complexity in terms of spatial arrangement and temporal dynamics. In this study our overall objective is to assess the Gross Primary Production (GPP) dynamics of a Dehesa ecosystem situated in Central Spain by analyzing time series (2004-2008) of two models: (1) GPP provided by Remote Sensing Images of sensor MODIS (MOD17A2 product) and (2) GPP estimated by the implementation of a Site Specific Light Use Efficiency model based as MODIS model on Monteith equation (1972), but taking into account local ecological and meteorological parameters. Both models have been compared with the Production provided by an Eddy Covariance (EC) flux Tower that is located in our study area. In addition, dynamic relationships between models of GPP with Precipitation and Soil Water Content have been investigated by means of cross

  15. Volatile Organic Compound Emission from Quercus suber, Quercus canariensis, and its hybridisation product Quercus afares

    Science.gov (United States)

    Welter, S.; Bracho Nuñez, A.; Staudt, M.; Kesselmeier, J.

    2009-04-01

    Oaks represent one of the most important plant genera in the Northern hemisphere and include many intensively VOC emitting species. The major group constitutes the isoprene emitters, but also monoterpene emitters and non-emitters can be found. These variations in the oak species might partly be due to their propensity for inter- and intraspecific hybridisation. This study addresses the foliar VOC production of the former hybridisation product the deciduous Quercus afares and its parents, two very distant species: the evergreen monoterpene emitter Quercus suber and the deciduous isoprene emitter Quercus canariensis. The measurements were performed in Southern France, applying two different methods. Plants were investigated in situ in the field with a portable gas exchange measuring system as well as in the laboratory on cut branches with an adapted enclosure system. Quercus afares was found to be a monoterpene emitting species. However, the monoterpene emission was lower and the composition different to that of Quercus suber. Whereas Quercus suber trees belonged to the pinene type most individuals of Quercus afares were identified to represent a limonene type. Quercus canariensis emitted besides high amounts of isoprene also linalool and (Z)-3-hexenylacetate. Emissions from Quercus suber and Quercus afares were higher in the field measurements than in the laboratory on cut branches whereas Quercus canariensis exhibited lower isoprene emissions from cut branches. The results demonstrate the need of further emission studies on a plant species level.

  16. Experimental Test of Heat Treatment Effect on Physical Properties of Red Oak (Quercus falcate Michx. and Southern Pine (Pinus taeda L.

    Directory of Open Access Journals (Sweden)

    Derya Sevim Korkut

    2014-11-01

    Full Text Available The objective of this work was to evaluate the effect of heat treatment and compression on the swelling and surface roughness of Southern red oak (Quercus falcate Michx. and Southern pine (Pinus taeda L.. Specimens were exposed to temperature levels of 110 °C or 200 °C for 8 h before they were compressed using 2.5 MPa pressure for 5 min. Swelling values of the control and heat-treated samples in three grain orientations were evaluated by soaking them in water for 48 h. A stylus method was employed to determine the surface characteristics of the samples. Three main roughness parameters, namely mean arithmetic deviation of profile (Ra, mean peak-to-valley height (Rz, and maximum roughness (Rmax were used to evaluate the effect of heat treatment on surface characteristics of the samples. Oak and pine specimens had 39.8% and 28.7% lower tangential swelling values, respectively, than those of control samples as a result of exposure to a temperature of 200 °C. Heat treatment did not make any significant difference on surface quality. Micrographs taken from cross sections of the specimens revealed that there was some cell distortion and modification due to heat treatment as well as compression. Combination of heat treatment and compression can be considered an alternative method to improve certain physical properties of these two species.

  17. Top-down control of herbivory by birds and bats in the canopy of temperate broad-leaved oaks (Quercus robur.

    Directory of Open Access Journals (Sweden)

    Stefan M Böhm

    Full Text Available The intensive foraging of insectivorous birds and bats is well known to reduce the density of arboreal herbivorous arthropods but quantification of collateral leaf damage remains limited for temperate forest canopies. We conducted exclusion experiments with nets in the crowns of young and mature oaks, Quercus robur, in south and central Germany to investigate the extent to which aerial vertebrates reduce herbivory through predation. We repeatedly estimated leaf damage throughout the vegetation period. Exclusion of birds and bats led to a distinct increase in arthropod herbivory, emphasizing the prominent role of vertebrate predators in controlling arthropods. Leaf damage (e.g., number of holes differed strongly between sites and was 59% higher in south Germany, where species richness of vertebrate predators and relative oak density were lower compared with our other study site in central Germany. The effects of bird and bat exclusion on herbivory were 19% greater on young than on mature trees in south Germany. Our results support previous studies that have demonstrated clear effects of insectivorous vertebrates on leaf damage through the control of herbivorous arthropods. Moreover, our comparative approach on quantification of leaf damage highlights the importance of local attributes such as tree age, forest composition and species richness of vertebrate predators for control of arthropod herbivory.

  18. Evidence on the Adaptive Recruitment of Chinese Cork Oak (Quercus variabilis Bl.: Influence on Repeated Germination and Constraint Germination by Food-Hoarding Animals

    Directory of Open Access Journals (Sweden)

    Yifeng Zhang

    2016-02-01

    Full Text Available In drought temperate forest, seedling recruitment is highly dependent on seed burial by native animal dispersers. To prolong seed storage, animals often take measures to impede seed germination. Aiming to understand the strategic balance between the natural seed germination and the role played by animals in the constraint germination procedures, we investigated the stages on the germinated acorns of Chinese cork oak (Quercus variabilis Bl. and the rodents’ behavior on the consequential delay in developmental processes of acorns in Mt. Taihangshan area of Jiyuan, Henan, China. The results showed that (1 Apodemus peninsulae Thomas excise radicles from germinated acorns before hoarding; (2 radicle-excised acorns re-germinate successfully if the excised radicle was un-lignified, but reverse if excised radicle was lignified; and (3 seedlings derived from radicle-excised acorns produce more lateral roots than that of sound acorns. We conclude that rodents take the radicle-excision behavior as a deliberate mechanism to slow the rapid germination of acorns; nevertheless, the acorns adaptively respond to this negative treatment and counteract the constraint from rodents by regermination to preserve the viability of the seeds. Consequently, this plays a significant role in forest recruitment. This study proves the new survival model of Chinese cork oak against animal predation, and will broaden theories of animal-forest interaction, forest succession and can be used as a meaningful venture to temperate forest restoration efforts.

  19. Gene movement and genetic association with regional climate gradients in California valley oak (Quercus lobata Née) in the face of climate change

    Science.gov (United States)

    Sork, Victoria L.; Davis, Frank W.; Westfall, Robert; Flint, Alan L.; Ikegami, Makihiko; Wang, Hongfang; Grivet, Delphine

    2010-01-01

    Rapid climate change jeopardizes tree populations by shifting current climate zones. To avoid extinction, tree populations must tolerate, adapt, or migrate. Here we investigate geographic patterns of genetic variation in valley oak, Quercus lobata N??e, to assess how underlying genetic structure of populations might influence this species' ability to survive climate change. First, to understand how genetic lineages shape spatial genetic patterns, we examine historical patterns of colonization. Second, we examine the correlation between multivariate nuclear genetic variation and climatic variation. Third, to illustrate how geographic genetic variation could interact with regional patterns of 21st Century climate change, we produce region-specific bioclimatic distributions of valley oak using Maximum Entropy (MAXENT) models based on downscaled historical (1971-2000) and future (2070-2100) climate grids. Future climatologies are based on a moderate-high (A2) carbon emission scenario and two different global climate models. Chloroplast markers indicate historical range-wide connectivity via colonization, especially in the north. Multivariate nuclear genotypes show a strong association with climate variation that provides opportunity for local adaptation to the conditions within their climatic envelope. Comparison of regional current and projected patterns of climate suitability indicates that valley oaks grow in distinctly different climate conditions in different parts of their range. Our models predict widely different regional outcomes from local displacement of a few kilometres to hundreds of kilometres. We conclude that the relative importance of migration, adaptation, and tolerance are likely to vary widely for populations among regions, and that late 21st Century conditions could lead to regional extinctions. ?? 2010 Blackwell Publishing Ltd.

  20. Biomass, Carbon and Nutrient Storage in a 30-Year-Old Chinese Cork Oak (Quercus Variabilis Forest on the South Slope of the Qinling Mountains, China

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    Yang Cao

    2015-04-01

    Full Text Available Chinese cork oak (Quercus variabilis forests are protected on a large-scale under the Natural Forest Protection (NFP program in China to improve the ecological environment. However, information about carbon (C storage to increase C sequestration and sustainable management is lacking. Biomass, C, nitrogen (N and phosphorus (P storage of trees, shrubs, herb, litter and soil (0–100 cm were determined from destructive tree sampling and plot level investigation in approximately 30-year old Chinese cork oak forests on the south slope of the Qinling Mountains. There was no significant difference in tree components’ biomass estimation, with the exception of roots, among the available allometric equations developed from this study site and other previous study sites. Leaves had the highest C, N and P concentrations among tree components and stems were the major compartments for tree biomass, C, N and P storage. In contrast to finding no difference in N concentrations along the whole soil profile, higher C and P concentrations were observed in the upper 0–10 cm of soil than in the deeper soil layers. The ecosystem C, N, and P storage was 163.76, 18.54 and 2.50 t ha−1, respectively. Soil (0–100 cm contained the largest amount of C, N and P storage, accounting for 61.76%, 92.78% and 99.72% of the total ecosystem, followed by 36.14%, 6.03% and 0.23% for trees, and 2.10%, 1.19% and 0.03% for shrubs, herbs and litter, respectively. The equations accurately estimate ecosystem biomass, and the knowledge of the distribution of C, N and P storage will contribute to increased C sequestration and sustainable management of Chinese cork oak forests under the NFP program.

  1. Differences in photosynthesis and isoprene emission in post oak (Quercus stellata) and sweetgum (Liquidambar styraciflua) trees along an urban-to-rural gradient in Texas

    Science.gov (United States)

    Crossett, C.; Lahr, E.; Haas, G.; Schade, G. W.

    2014-12-01

    Many plants produce isoprene, a volatile organic compound that can mitigate damage to photosynthetic systems during short- or long-term increases in leaf temperature. After its production within leaves, isoprene is emitted to the atmosphere and influences regional atmospheric chemistry. Here, we use an urban-to-rural gradient to explore future effects of climate change on tree eco-physiology and feedbacks to atmospheric chemistry. Urban areas mimic many of the conditions expected to occur in the future; in particular, cities have warmer temperatures due to the urban heat island (UHI) effect, and less water availability relative to rural areas. Along a 90 km urban-to-rural gradient, we measured photosynthesis and isoprene emission from trees at three sites in eastern Texas: Houston (urban), The Woodlands (suburban) and Sam Houston National Forest (rural). Isoprene emission from post oak (Quercus stellata) was higher in Houston than the other sites, and when leaf temperatures were increased above ambient conditions, trees produced more isoprene. Leaves produced more isoprene at high leaf temperatures in early summer than in late summer, suggesting gradual acclimation of photosynthetic processes over the course of the summer. We also found that sweetgum (Liquidambar styraciflua) emitted more isoprene than post oak, but when leaf temperatures were increased, isoprene emission was exhausted more quickly in sweetgum relative to post oak. At the same time, post oak maintained higher levels of photosynthesis seasonally and during short-term temperature increases. Both post oak and sweetgum are significant isoprene emitters and represent approximately two and four percent crown cover in the United States, respectively. Our results suggest that in a warming climate, we can expect trees to produce more isoprene seasonally and in response to short-term temperature extremes, and that species-specific differences in photosynthesis and isoprene emission may play an important role

  2. Evaluation of the degree of healthiness of the pedunculate oak (Quercus robur L. acorns in the Włoszczowa– Jędrzejów Nature Park and its neighbouring area

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    Bąk-Badowska Jolanta

    2017-03-01

    Full Text Available The aim of the study was to demonstrate the degree of healthiness of the pedunculate oak (Quercus robur acorns found in the Włoszczowa-Jędrzejów Nature Park (abbreviation: W-JOChK and in the neighbouring area. It was dealt with by making the analysis of health of the acorns (total 3,600. The research material included the samples of fallen down acorns, collected under the pedunculate oaks in Kurzelów (W-JOChK, as well as Żelisławice. The study was conducted from late September 2014 to early October 2015.

  3. Content of plant growth regulators in the developing seeds of oak (Quercus robur L.) III. Kinetin-like substances

    OpenAIRE

    Leszek Michalski

    2015-01-01

    Kinetin-like substances in developing oak seeds have been investigated. The methods of extraction, fractionation, paper and column chromatography and bioassays, demonstrated that an active cell division factor appears in various phases of seeds development. A high level of this substance has been found mainly in developing acorns. In the course of thier ripening this level decreases considerably.

  4. Content of plant growth regulators in the developing seeds of oak (Quercus robur L. III. Kinetin-like substances

    Directory of Open Access Journals (Sweden)

    Leszek Michalski

    2015-01-01

    Full Text Available Kinetin-like substances in developing oak seeds have been investigated. The methods of extraction, fractionation, paper and column chromatography and bioassays, demonstrated that an active cell division factor appears in various phases of seeds development. A high level of this substance has been found mainly in developing acorns. In the course of thier ripening this level decreases considerably.

  5. Land use practices and ectomycorrhizal fungal communities from oak woodlands dominated by Quercus suber L. considering drought scenarios.

    Science.gov (United States)

    Azul, Anabela Marisa; Sousa, João Paulo; Agerer, Reinhard; Martín, María P; Freitas, Helena

    2010-02-01

    Oak woodlands in the Mediterranean basin have been traditionally converted into agro-silvo-pastoral systems and exemplified sustainable land use in Europe. In Portugal, in line with the trend of other European countries, profound changes in management options during the twentieth century have led to landscape simplification. Landscapes are dynamic and the knowledge of future management planning combining biological conservation and soil productivity is needed, especially under the actual scenarios of drought and increasing evidence of heavy oak mortality. We examined the ectomycorrhizal (ECM) fungal community associated with cork oak in managed oak woodlands (called montado) under different land use practices, during summer. ECM fungal richness and abundance were assessed in 15 stands established in nine montados located in the Alentejo region (southern Portugal), using morphotyping and ITS rDNA analysis. Parameters related to the montados landscape characteristics, land use history over the last 25 years, climatic and edaphic conditions were taken into account. Fifty-five ECM fungal taxa corresponding to the most abundant fungal symbionts were distinguished on cork oak roots. Cenococcum geophilum and the families Russulaceae and Thelephoraceae explained 56% of the whole ECM fungal community; other groups were represented among the community: Cortinariaceae, Boletaceae, Amanita, Genea, Pisolithus, Scleroderma, and Tuber. There were pronounced differences in ECM fungal community structure among the 15 montados stands: C. geophilum was the only species common to all stands, tomentelloid and russuloid species were detected in 87-93% of the stands, Cortinariaceae was detected in 60% of the stands, and the other groups were more unequally distributed. Ordination analysis revealed that ECM fungal richness was positively correlated with the silvo-pastoral exploitation regime and low mortality of cork oak, while ECM fungal abundance was positively correlated with extensive

  6. Age-related variation in carbon allocation at tree and stand scales in beech (Fagus sylvatica L.) and sessile oak (Quercus petraea (Matt.) Liebl.) using a chronosequence approach.

    Science.gov (United States)

    Genet, H; Bréda, N; Dufrêne, E

    2010-02-01

    Two types of physiological mechanisms can contribute to growth decline with age: (i) the mechanisms leading to the reduction of carbon assimilation (input) and (ii) those leading to modification of the resource economy. Surprisingly, the processes relating to carbon allocation have been little investigated as compared to research on the processes governing carbon assimilation. The objective of this paper was thus to test the hypothesis that growth decrease related to age is accompanied by changes in carbon allocation to the benefit of storage and reproductive functions in two contrasting broad-leaved species: beech (Fagus sylvatica L.) and sessile oak (Quercus petraea (Matt.) Liebl.). Age-related changes in carbon allocation were studied using a chronosequence approach. Chronosequences, each consisting of several even-aged stands ranging from 14 to 175 years old for beech and from 30 to 134 years old for sessile oak, were divided into five or six age classes. In this study, carbon allocations to growth, storage and reproduction were defined as the relative amount of carbon invested in biomass increment, carbohydrate increment and seed production, respectively. Tree-ring width and allometric relationships were used to assess biomass increment at the tree and stand scales. Below-ground biomass was assessed using a specific allometric relationship between root:shoot ratio and age, established from the literature review. Seasonal variations of carbohydrate concentrations were used to assess carbon allocation to storage. Reproduction effort was quantified for beech stands by collecting seed and cupule production. Age-related flagging of biomass productivity was assessed at the tree and stand scales, and carbohydrate quantities in trees increased with age for both species. Seed and cupule production increased with stand age in beech from 56 gC m(-)(2) year(-1) at 30 years old to 129 gC m(-2) year(-1) at 138 years old. In beech, carbon allocation to storage and

  7. 欧洲栓皮栎种子催芽试验%Seed Germination Trial with Cork Oak (Quercus suber)

    Institute of Scientific and Technical Information of China (English)

    佘远国

    2000-01-01

    @@ 欧洲栓皮栎(Quercus rariabilis B1.)是一种重要的软木工业原料.60年代从苏联引种我省,由于疏于管理,目前,全省仅存100株,濒于绝迹.为了拯救优良物种,加大欧洲栓皮栎种质资源收集,加速物种繁殖.实生繁殖时,为了确定合理的播种量以及改进种子贮藏方法,对种子进行不同药剂催芽处理,测定发芽率,平均发芽速,根的生长量,比较不同药剂对种子发芽的影响效果.

  8. Tree-Ring Chronology of Pedunculate Oak (Quercus robur and its Potential for Development of Dendrochronological Research in Croatia

    Directory of Open Access Journals (Sweden)

    Katarina Čufar

    2014-06-01

    Full Text Available We present the local tree-ring chronology of pedunculate oak (Qercus robur from Kobiljak near Zagreb, Croatia (16º09’ E, 45º49’ N, 140 m a.s.l.. The chronology is based on 17 trees and is 127 years long and covers the period of 1883-2009. The well replicated part of the residual version of the ARSTAN chronology with SSS>0.80 (interval of 88 years, period 1922-2009 was used for dendroclimatological analysis, which showed that June precipitation has positive and temperature has negative effect on tree-ring variation. Comparison with 40 available oak chronologies from the surrounding countries confi rmed its good teleconnection with 2 local oak chronologies from Austria, 2 from Hungary, and 3 from Slovenia. It also exhibits good heteroconnection, i.e. similarity with chronologies of beech (Fagus sylvatica, from various sites in Slovenia. The similarities can be ascribed to response to common climatic factors. The results indicate that the chronology could be a good reference point for constructing a longer regional chronology in Croatia and surrounding countries, which could be used for different purposes including dating of objects of cultural heritage.

  9. Application of Nearest Neighbor Indices in Persian Oak (Quercus brantii var. persica Coppice Stands of Zagros Forests

    Directory of Open Access Journals (Sweden)

    Y. Erfanifard

    2014-03-01

    Full Text Available The ecological relationship between trees is important in the sustainable management of forests. Studying this relationship in spatial ecology, different indices are applied that are based on distance to nearest neighbor. The aim of this research was introduction of important indices based on nearest neighbor analysis and their application in the investigation of ecological relationship between Persian oak coppice trees in Zagros forests. A 9 ha plot of these forests in Kohgilouye - BoyerAhmad province was selected that was completely homogeneous. This plot was covered with Persian oak coppice trees that their point map was obtained after registering their spatial location. Five nearest neighbor indices of G(r, F(r, J(r, GF(r and CE were then applied to study the spatial pattern and relationship of these trees. The results showed that Persian oak coppice trees were located regularly in the homogeneous plot and they were not dependent ecologically. These trees were independent and did not affect the establishment of each other.

  10. Sap flow measurements combining sap-flux density radial profiles with punctual sap-flux density measurements in oak trees (Quercus ilex and Quercus pyrenaica) - water-use implications in a water-limited savanna-

    Science.gov (United States)

    Reyes, J. Leonardo; Lubczynski1, Maciek W.

    2010-05-01

    measurements using the HFD-measured radial profiles. The standard TDP daily mean of sap-flux density was 95% higher than the 2cm equivalent of the HFD for Q. ilex and 70% higher for Q. pyrenaica. NTG-corrected TDP daily mean of sap-flux density was 34% higher than HFD for Q. ilex and 47% lower for Q. pyrenaica. Regarding sap flow measurements, the standard TDP sap flow was 81% higher than HFD sap flow for Q. ilex and 297% for Q. pyrenaica. The NTG-corrected TDP sap flow was 24% higher than HFD sap flow for Q. ilex and 23% for Q. pyrenaica. The radial correction, for TDP-NTG-corrected sap-flux density, produced sap-flow measurements in well agreement with HFD, just slightly lower (-3% Q.i. and -4% Q.p.). The TDP-HFD sap flow data acquired in dry season over the savanna type of sparsely distributed oak trees (Q. ilex & Q. pyrenaica) showed that the TDP method must be corrected for NTG and for radial variability of sap flux density in trees with sapwood thicker than 2 cm. If such corrections are not taken into consideration, the amount of accounted water used by the trees is prone to overestimation, especially for Quercus pyrenaica. The obtained results indicate also that the combination of HFD and TDP leads to an efficient and accurate operational sap flow measurement schema that is currently in the optimization stage.

  11. Differential radial growth patterns between beech (Fagus sylvatica L.) and oak (Quercus robur L.) on periodically waterlogged soils.

    Science.gov (United States)

    Scharnweber, Tobias; Manthey, Michael; Wilmking, Martin

    2013-04-01

    Climate scenarios for northern Central Europe project rising temperatures and increasing frequency and intensity of droughts but also a shift in precipitation pattern with more humid winters. This in turn may result in soil waterlogging during the following spring, leading to increasing stress for trees growing on hydric sites. The influence of waterlogging on growth of common beech and pedunculate oak has been studied intensively on seedlings under experimental conditions. However, the question remains whether results of these studies can be transferred to mature trees growing under natural conditions. To test this, we investigated general growth patterns and climate-growth relationships in four mature stands of beech and oak growing on hydromorphic soils (Stagnosols) in northeast Germany using dendrochronological methods. Our results confirmed the expected tolerance of oak to strong water-level fluctuations. Neither extremely wet conditions during spring nor summer droughts significantly affected its radial growth. Oak growth responded positively to warmer temperatures during previous year October and March of the current year of ring formation. Contrary to our expectations, also beech showed relatively low sensitivity to periods of high soil water saturation. Instead, summer drought turned out to be the main climatic factor influencing ring width of beech even under the specific periodically wet soil conditions of our study. This became evident from general climate-growth correlations over the last century as well as from discontinuous (pointer year) analysis with summer drought being significantly correlated to the occurrence of growth depressions. As ring width of the two species is affected by differing climate parameters, species-specific chronologies show no coherence in high-frequency variations even for trees growing in close proximity. We assume differences in rooting depth as the main reason for the differing growth patterns and climate correlations of

  12. The bark of the branches of holm oak (Quercus ilex L.) for a retrospective study of trace elements in the atmosphere.

    Science.gov (United States)

    Drava, Giuliana; Brignole, Daniele; Giordani, Paolo; Minganti, Vincenzo

    2017-04-01

    Tree bark has proved to be a useful bioindicator for trace elements in the atmosphere, however it reflects an exposure occurring during an unidentified period of time, so it provides spatial information about the distribution of contaminants in a certain area, but it cannot be used to detect temporal changes or trends, which is an important achievement in environmental studies. In order to obtain information about a known period of time, the bark collected from the annual segments of tree branches can be used, allowing analyses going back 10-15 years with annual resolution. In the present study, the concentrations of As, Cd, Co, Cu, Fe, Mn, Ni, Pb, V and Zn were measured by atomic emission spectrometry in a series of samples covering the period from 2001 to 2013 in an urban environment. Downward time trends were significant for Cd, Pb and Zn. The only trace element showing an upward time trend was V. The concentrations of the remaining six trace elements were constant over time, showing that their presence in bark is not simply proportional to the duration of exposure. This approach, which is simple, reliable and widely applicable at a low cost, allows the "a posteriori" reconstruction of atmospheric trace element deposition when or where no monitoring programme is in progress and no other natural archives are available. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Critical factors in the limited occurrence of the Japanese tree sap mite Hericia sanukiensis (Acari: Astigmata: Algophagidae) inhabiting the sap of the oak Quercus acutissima.

    Science.gov (United States)

    Hayashi, Kyohei; Ichikawa, Toshihide; Yasui, Yukio

    2011-08-01

    Hericia sanukiensis (Astigmata: Algophagidae) is a semi-aquatic mite inhabiting fermented sap flux of the Japanese sawtooth oak (Quercus acutissima) and utilizes Nitidulidae (Coleoptera) as the dispersal (phoretic) carrier. Although nitidulid beetles are commonly found in sap flux, the occurrence of H. sanukiensis has been extremely limited to a few trees in Shikoku Island, Kagawa Prefecture, Japan. To elucidate the critical factors limiting the occurrence of this species, we compared several physical and biological characteristics of sap-exudation points, including the structure and temperature of tree trunks, period and abundance of sap exudation, and seasonal occurrence and dispersal behavior of nitidulid beetles between environments with and without mites. During the two consecutive years of field research, we found that only sap-exudation points with obvious tree holes (ringent area >10 cm², depth >10 cm) had sustained mite populations throughout the observation period. In contrast, for the sap-exudation points lacking tree holes, H. sanukiensis temporally (from spring to autumn) colonized only when the sap production was considerably high. Thus, we suggest that the settlement of H. sanukiensis populations requires tree holes as an overwintering habitat. Nitidulid beetles also concentrated in areas with high sap production and did not disperse from such habitats during the sap flow season. This indicates that H. sanukiensis mites may only disperse and colonize new habitats at very limited opportunities, such as drastic habitat deterioration, which may promote the movement of their carrier. Taken together, these findings may explain the limited occurrence of this mite species.

  14. Drivers of radial growth and carbon isotope discrimination of bur oak (Quercus macrocarpa Michx.) across continental gradients in precipitation, vapour pressure deficit and irradiance.

    Science.gov (United States)

    Voelker, Steven L; Meinzer, Frederick C; Lachenbruch, Barbara; Brooks, J Renée; Guyette, Richard P

    2014-03-01

    Tree-ring characteristics are commonly used to reconstruct climate variables, but divergence from the assumption of a single biophysical control may reduce the accuracy of these reconstructions. Here, we present data from bur oaks (Quercus macrocarpa Michx.) sampled within and beyond the current species bioclimatic envelope to identify the primary environmental controls on ring-width indices (RWIs) and carbon stable isotope discrimination (Δ(13) C) in tree-ring cellulose. Variation in Δ(13) C and RWI was more strongly related to leaf-to-air vapour pressure deficit (VPD) at the centre and western edge of the range compared with the northern and wettest regions. Among regions, Δ(13) C of tree-ring cellulose was closely predicted by VPD and light responses of canopy-level Δ(13) C estimated using a model driven by eddy flux and meteorological measurements (R(2)  = 0.96, P = 0.003). RWI and Δ(13) C were positively correlated in the drier regions, while they were negatively correlated in the wettest region. The strength and direction of the correlations scaled with regional VPD or the ratio of precipitation to evapotranspiration. Therefore, the correlation strength between RWI and Δ(13) C may be used to infer past wetness or aridity from paleo wood by determining the degree to which carbon gain and growth have been more limited by moisture or light. © 2013 John Wiley & Sons Ltd.

  15. Oxygen isotope signatures of transpired water vapor - the role of isotopic non-steady-state transpiration of Mediterranean cork-oaks (Quercus suber L.)under natural conditions

    Science.gov (United States)

    Dubbert, Maren; Piayda, Arndt; Cuntz, Matthias; Werner, Christiane

    2014-05-01

    Oxygen isotope signatures of transpired water vapor (δT) are a powerful tracer of water movement from plants to the global scale, but little is known on short-term variability of δT as direct high-frequency measurements are lacking. A laser spectrometer was coupled to a gas-exchange chamber directly estimating branch-level fluxes and δT to evaluate a modeling approach and investigate the role of isotopic non-steady-state transpiration under natural conditions in distinct seasons in cork-oaks (Quercus suber L.). The isotope signature of transpiration (δT) always deviated from steady-state predictions (ΔT) throughout most of the day even when leaf water at the evaporating sites is near isotopic steady-state. Thus, ΔT is further amplified compared to deviations of leaf water isotopes from steady-state, specifically in dry conditions. High agreement was found for direct estimates and modeled ΔT assuming non-steady-state conditions of leaf-water at the evaporating sites. Strong isoforcing on the atmosphere of transpiration in isotopic non-steady-state imply that short-term variations in δT have likely consequences for large-scale applications, e.g. partitioning of ecosystem evapotranspiration or carbon fluxes using C18O16O, or satellite-based applications.

  16. Effects of partial defoliation on carbon and nitrogen partitioning and photosynthetic carbon uptake by two-year-old cork oak (Quercus suber) saplings.

    Science.gov (United States)

    Cerasoli, S; Scartazza, A; Brugnoli, E; Chaves, M M; Pereira, J S

    2004-01-01

    At the end of the growing season in late July, 20-month-old cork oak (Quercus suber L.) saplings were partially defoliated (63% of leaf area) to evaluate their ability to recover leaf area after defoliation. At 18 and 127 days after defoliation, changes in starch and nitrogen pools were determined in leaves and perennial organs, and variations in photosynthetic carbon uptake were investigated. To determine the role of stored nitrogen in regrowth after defoliation, plant nitrogen was labeled in the previous winter by enriching the nutrient solution with 15N. Plants recovered the lost leaf area in 127 days. Although there was remobilization of starch and nitrogen from leaves and perennial organs, the availability of resources for growth in the following spring was not decreased by defoliation. On the contrary, starch concentration in coarse roots was higher in defoliated saplings than in control saplings, presumably as a result of the higher net CO2 exchange rate in newly developed leaves compared with pre-existing leaves.

  17. Seed-hoarding of Edward's long-tailed rats Leopoldamys edwardsi in response to weevil infestation in cork oak Quercus variabilis

    Institute of Scientific and Technical Information of China (English)

    Jinrui CHENG; Hongmao ZHANG

    2011-01-01

    Seed hoarders show different hoarding and eating responses towards insect-infested seeds that can affect the fitness of both the seeds and insects. It remains unclear how seed hoarders adopt different strategies in eating and hoarding infested seeds with and without larvae concealed inside. Here we investigated hoarding and eating responses of Edward's long-tailed rats Leopoldamys edwardsi (scatter hoarders) to weevil infestation of cork oak Quercus variabilis seeds within outdoor enclosures. We provided sound seeds, larvae-emerged seeds, (infested seeds where larvae have emerged) and larvae-concealed seeds (infested seeds with larvae concealed inside) to subjects independently (each seed type presented separately) and in pai-wise combinations (sound and larvae-emerged seeds; sound and larvae-concealed seeds). We found that L. Edwardsi removed, scatter hoarded and ate fewer larvae-emerged seeds than sound seeds. No difference was found between sound seeds and larvae-concealed seeds. These results suggest that sound and larvae-concealed seeds are more favored by L. Edwardsi than larvae-emerged seeds. We posit that not only plants but also insects may benefit from the behavioral responses of hoarders to seed infestation under natural conditions.

  18. Seed-hoarding of Edward's long-tailed rats Leopoldamys edwardsi in response to weevil infestation in cork oak Quer-cus variabilis

    Directory of Open Access Journals (Sweden)

    Jinrui CHENG, Hongmao ZHANG

    2011-02-01

    Full Text Available Seed hoarders show different hoarding and eating responses towards insect-infested seeds that can affect the fitness of both the seeds and insects. It remains unclear how seed hoarders adopt different strategies in eating and hoarding infested seeds with and without larvae concealed inside. Here we investigated hoarding and eating responses of Edward’s long-tailed rats Leopoldamys edwardsi (scatter hoarders to weevil infestation of cork oak Quercus variabilis seeds within outdoor enclosures. We provided sound seeds, larvae-emerged seeds, (infested seeds where larvae have emerged and larvae-concealed seeds (infested seeds with larvae concealed inside to subjects independently (each seed type presented separately and in pairwise combinations (sound and larvae-emerged seeds; sound and larvae-concealed seeds. We found that L. edwardsi removed, scatter hoarded and ate fewer larvae-emerged seeds than sound seeds. No difference was found between sound seeds and larvae-concealed seeds. These results suggest that sound and larvae-concealed seeds are more favored by L. edwardsi than larvae-emerged seeds. We posit that not only plants but also insects may benefit from the behavioral responses of hoarders to seed infestation under natural conditions [Current Zoology 57 (1: 50–55, 2011].

  19. Humus characteristics and seasonal changes of soil arthropod communities in a natural sessile oak (Quercus petraea L.) stand and adjacent Austrian pine (Pinus nigra Arnold) plantation.

    Science.gov (United States)

    Cakir, Meric; Makineci, Ender

    2013-11-01

    In order to assess the effects of conversion of natural stands into plantations, soil invertebrate micro- and macroarthropod communities were evaluated for their abundance and richness in a sessile oak (SO; Quercus petraea L.) stand and adjacent Austrian pine (AP; Pinus nigra Arnold) plantation. Sites were sampled four times a year in 3-month intervals from May 2009 to February 2010. Humus characteristics such as total mass; carbon, lignin, and cellulose contents; and C/N ratio were significantly different between SO and AP. Statistically significant differences were detected on soil pH, carbon and nitrogen contents, and electrical conductivity between the two sites. The number of microarthropods was higher in AP than in the SO site. The annual mean abundance values of microarthropods in a square meter were 67,763 in AP and 50,542 in SO, and the annual mean abundance values of macroarthropods were 921 m(-2) in AP and 427 m(-2) in SO. Among the soil microarthropods, Acari and Collembola were the dominant groups. Shannon's diversity index was more affected by evenness than species number despite the species diversity (H') of soil arthropods being generally higher in the SO stand. The abundance of microarthropods showed clear seasonal trends depending upon the humidity of the soil.

  20. Secretome analysis identifies potential virulence factors of Diplodia corticola, a fungal pathogen involved in cork oak (Quercus suber) decline.

    Science.gov (United States)

    Fernandes, Isabel; Alves, Artur; Correia, António; Devreese, Bart; Esteves, Ana Cristina

    2014-01-01

    The characterisation of the secretome of phytopathogenic fungi may contribute to elucidate the molecular mechanisms of pathogenesis. This is particularly relevant for Diplodia corticola, a fungal plant pathogen belonging to the family Botryosphaeriaceae, whose genome remains unsequenced. This phytopathogenic fungus is recognised as one of the most important pathogens of cork oak, being related to the decline of cork oak forests in the Iberian Peninsula. Unfortunately, secretome analysis of filamentous fungi is limited by the low protein concentration and by the presence of many interfering substances, such as polysaccharides, which affect the separation and analysis by 1D and 2D gel electrophoresis. We compared six protein extraction protocols concerning their suitability for further application with proteomic workflows. The protocols involving protein precipitation were the most efficient, with emphasis on TCA-acetone protocol, allowing us to identify the most abundant proteins on the secretome of this plant pathogen. Approximately 60% of the spots detected were identified, all corresponding to extracellular proteins. Most proteins identified were carbohydrate degrading enzymes and proteases that may be related to D. corticola pathogenicity. Although the secretome was assessed in a noninfection environment, potential virulence factors such as the putative glucan-β-glucosidase, neuraminidase, and the putative ferulic acid esterase were identified. The data obtained forms a useful basis for a deeper understanding of the pathogenicity and infection biology of D. corticola. Moreover, it will contribute to the development of proteomics studies on other members of the Botryosphaeriaceae.

  1. Increased Drying Rate Lowers the Critical Water Content for Survival in Embryonic Axes of English Oak (Quercus robur L.) Seeds

    Institute of Scientific and Technical Information of China (English)

    Tobias M. Ntuli; William E. Finch-Savage; Patricia Berjak; Norman W. Pammenter

    2011-01-01

    The potential to cryopreserve embryonic axes of desiccation-sensitive (recalcitrant) seeds is limited by damage during the desiccation necessary for low temperature survival, but the basis of this injury and how to reduce it is not well understood. The effects of drying rate on the viability, respiratory metabolism and free radical-mediated processes were therefore investigated during dehydration of Quercus robur L. embryonic axes. Viability, assessed by evidence of germination and tetrazolium staining, showed a sharp decline at 0.27 and 0.8 g/g during rapid (<12 h) or slow (3 d) dehydration, respectively. Rapid dehydration therefore lowered the critical water content for survival. At any given water content rapid dehydration was associated with higher activities of the free radical processing enzymes, superoxide dismutase, catalase and glutathione reductase and lower levels of hydroperoxide and membrane damage. Rapid dehydration was also associated with lower malate dehydrogenase activity, and a reduced decline in phosphofructokinase activity and in levels of the oxidized form of nicotinamide dinucleotide. Ageing may have contributed to increased damage during slow dehydration, since viability declined even in hydrated storage after 3 d. The results presented are consistent with rapid dehydration reducing the accumulation of damage resulting from desiccation induced aqueous-based deleterious reactions.

  2. Rhodotorula subericola sp. nov., an anamorphic basidiomycetous yeast species isolated from bark of Quercus suber (cork oak).

    Science.gov (United States)

    Belloch, C; Villa-Carvajal, M; Alvarez-Rodríguez, M L; Coque, J J R

    2007-07-01

    Two yeasts strains, Y-31(T) and Y-20B, pertaining to a previously unknown yeast species were isolated from bark of cork oak in Spain. Physiological characterization revealed a pattern of assimilation of carbon and nitrogen compounds compatible with members of the genus Rhodotorula. From sequence analysis of the D1/D2 region of the 26S rRNA gene, Rhodotorula cycloclastica and Rhodotorula philyla were related to the unknown species. Phylogenetic reconstruction based on the D1/D2 region of the 26S rRNA gene showed that the novel species clustered in a branch together with R. cycloclastica. The name Rhodotorula subericola sp. nov. is proposed, with isolate Y-31(T) (=CECT 11976(T)=CBS 10442(T)) the type strain of this novel taxon in the Microbotryum lineage, subclass Microbotryomycetidae, class Urediniomycetes of basidiomycetous yeasts.

  3. Vegetative propagation of Quercus suber L. by somatic embryogenesis. II. Plant regeneration from selected cork oak trees.

    Science.gov (United States)

    Hernández, I; Celestino, C; Alegre, J; Toribio, M

    2003-04-01

    The regeneration of somatic seedlings from selected 100-year-old cork oak trees is reported. The induction of somatic embryogenesis from leaves of epicormic shoots was significantly affected by genotype, harvesting time and their interaction. Leaves from all five selected trees produced somatic embryos when the segments of branches used as sources of epicormic shoots were collected in May. Genotype, but not the level of photosynthetically active radiation, affected the proliferation of the embryogenic lines and the number of detachable embryos that could be obtained from them. Genotype also affected several steps leading to conversion of somatic embryos, from germination to complete acclimatisation of somatic seedlings. Almost 40% of the somatic embryos from all lines germinated, showing coordinated root and shoot growth. Although the mean percentage of recovery for the whole process was low, plants could be regenerated from four of the five trees tested.

  4. Cultivation techniques in a 34 years old farming oak (Quercus robur L. plantation in the Arno valley (Tuscany

    Directory of Open Access Journals (Sweden)

    Serena Ravagni

    2015-12-01

    Full Text Available This report aims to provide a description of the cultivation techniques adopted at the oldest oak pure plantation (age 34 established within the environmental restoration plan of soil dumps at the Santa Barbara ENEL Company opencast mine in Cavriglia (AR. The goals of the initial plan, following which the plantation was carried out, were to (i verify the possibility of restoring the soil dump by using tree farming plantations and produce a range of valuable timber assortments; (ii test the growth potential of the oak species in a pure plantation. The plantation, carried out with a stem density of 1,111 trees per hectare, was managed by targeted practices (pruning up to the stem height of 4-5 m and then undertaking four thinnings.  A geometric-selective thinning was applied first and, later, periodical thinning from above was implemented, releasing, as a result, about 70 crop trees per hectare. In the meanwhile, it was possible to monitor  the growth parameters concerning dbh, tree height and crown diameter. The stem quality and the presence of epicormic branches were evaluated in 2013 and the relationship between the presence of epicormic branches and tree characteristics were also analyzed. The wood production was compared with other European plantations, especially from France. Today, 34 years after the plantation got started, the site is an interesting case-study of tree farming as it plays a consistent role within the environmental restoration of the area. The applied management system allowed to reach a noticeable wood production level andalso valuable timber assortments for industrial use. Crop trees (70 per hectare reached a mean dbh of 38.1 cm, the height of 22.3 m at the age of 34. 

  5. Introgression Threatens the Genetic Diversity of Quercus austrocochinchinensis (Fagaceae), an Endangered Oak: A Case Inferred by Molecular Markers

    Science.gov (United States)

    An, Miao; Deng, Min; Zheng, Si-Si; Jiang, Xiao-Long; Song, Yi-Gang

    2017-01-01

    Natural introgression can cause negative effects where rare species experience genetic assimilation and invade by their abundant congeners. Quercus austrocochinchinensis and Q. kerrii (subgenus Cyclobalanopsis) are a pair of closely related species in the Indo-China area. Morphological intermediates of the two species have been reported in this region. In this study, we used AFLP, SSR and two key leaf morphological diagnostic traits to study the two Q. austrocochinchinensis populations, two pure Q. kerrii and two putative hybrid populations in China. Rates of individual admixture were examined using the Bayesian clustering programs STRUCTURE and NewHybrids, with no a priori species assignment. In total, we obtained 151 SSR alleles and 781 polymorphic loci of AFLP markers. Population differentiation inferred by SSR and AFLP was incoherent with recognized species boundaries. Bayesian admixture analyses and principal coordinate analysis identified more hybrids and backcrossed individuals than morphological intermediates in the populations. SSR inferred a wide genetic assimilation in Q. austrocochinchinensis, except for subpopulation D2 in the core area of Xi-Shuang-Ban-Na Nature Reserve (XSBN). However, AFLP recognized more Q. austrocochinchinensis purebreds than SSR. Analysis using NewHybrids on AFLP data indicated that these hybridized individuals were few F2 and predominantly backcrosses with both parental species. All these evidences indicate the formation of a hybrid swarm at XSBN where the two species co-exist. Both AFLP and SSR recognized that the core protected area of XSBN (D2) has a high percentage of Q. austrocochinchinensis purebreds and a unique germplasm. The Hainan population and the other subpopulations of XSBN of the species might have lost their genetic integrity. Our results revealed a clear genetic differentiation in the populations and subpopulations of Q. austrocochinchinensis and ongoing introgression between Q. austrocochinchinensis and Q

  6. Analytical approaches to the determination of simple biophenols in forest trees such as Acer (maple), Betula (birch), Coniferus, Eucalyptus, Juniperus (cedar), Picea (spruce) and Quercus (oak).

    Science.gov (United States)

    Bedgood, Danny R; Bishop, Andrea G; Prenzler, Paul D; Robards, Kevin

    2005-06-01

    Analytical methods are reviewed for the determination of simple biophenols in forest trees such as Acer (maple), Betula (birch), Coniferus, Eucalyptus, Juniperus (cedar), Picea (spruce) and Quercus (oak). Data are limited but nevertheless clearly establish the critical importance of sample preparation and pre-treatment in the analysis. For example, drying methods invariably reduce the recovery of biophenols and this is illustrated by data for birch leaves where flavonoid glycosides were determined as 12.3 +/- 0.44 mg g(-1) in fresh leaves but 9.7 +/- 0.35 mg g(-1) in air-dried samples (data expressed as dry weight). Diverse sample handling procedures have been employed for recovery of biophenols. The range of biophenols and diversity of sample types precludes general procedural recommendations. Caution is necessary in selecting appropriate procedures as the high reactivity of these compounds complicates their analysis. Moreover, our experience suggests that their reactivity is very dependent on the matrix. The actual measurement is less contentious and high performance separation methods particularly liquid chromatography dominate analyses whilst coupled techniques involving electrospray ionization are becoming routine particularly for qualitative applications. Quantitative data are still the exception and are summarized for representative species that dominate the forest canopy of various habitats. Reported concentrations for simple phenols range from trace level (<0.1 microg g(-1)) to in excess of 500 microg g(-1) depending on a range of factors. Plant tissue is one of these variables but various biotic and abiotic processes such as stress are also important considerations.

  7. Addressing post-transplant summer water stress in Pinus pinea and Quercus ilex seedlings

    Directory of Open Access Journals (Sweden)

    Pardos M

    2015-06-01

    Full Text Available In central Spain, post-transplant water stress produces high seedling mortality after the first summer following outplanting. Our study was designed to determine whether survival and performance of outplanted stone pine (Pinus pinea and holm oak (Quercus ilex seedlings in a burned area could be improved by summer irrigation and mulching and to identify whether there is a species-specific adaptive capacity to respond to treatment and environment. Seedlings were outplanted in March 2011 in 200 planting holes in an area of 1.1 ha. Mulch was added in June; irrigation started in July and was repeated every week until mid-September. The severity of the 2011 summer drought constrained growth rates and photosynthetic characteristics, mainly in the non-irrigated seedlings, whose survival at the end of the year after planting was approximately 2.5%. Stone pine and holm oak seedlings responded more to irrigation than to mulching in terms of shoot growth, biomass and survival. Furthermore, stone pine seedlings were found to be more responsive to the partial alleviation of summer drought than holm oak seedlings. Irrigation alone produced similar results to those obtained when both irrigation and mulching were employed. In conclusion, first year summer irrigation should be considered as a planned adaptation measure in the management of outplanted Mediterranean ecosystems, because once a gravimetrically measured soil moisture level as low as 2% is achieved seedling survival and physiological performance can be guaranteed. However, the repercussions for the potential persistence of both species in the area will not only be related to the recurrence and intensity of summer droughts but also to drought duration.

  8. Growth, ectomycorrhization and biochemical parameters of Quercus ...

    African Journals Online (AJOL)

    daoudi

    2016-09-21

    Sep 21, 2016 ... stomatal conductance and photosynthesis of plants, which changes .... polyphenols were quantified after colorimetric reaction using Folin-. Ciocalteu ..... of different water and light intensities on cork oak (Quercus suber L.).

  9. Effects of fire temperature on the physical and chemical characteristics of the ash from two plots of Cork oak (Quercus Suber)

    Science.gov (United States)

    Ubeda, X.; Pereira, P.; Outeiro, L.; Martin, D.A.

    2009-01-01

    Cork oak, (Quercus suber) is widely distributed in the Mediterranean region, an area subject to frequent fires. The ash produced by burning can have impacts on the soil status and water resources that can differ according to the temperature reached during fire and the characteristics of the litter, defined as the dead organic matter accumulated on the soil surface prior to the fire. The aim of this work is to determine the physical and chemical characteristics of ash produced in laboratory experiments to approximate conditions typical of fires in this region. The litter of Quercus suber collected from two different plots on the Iberian Peninsula, Mas Bassets (Catalonia) and Albufeira (Portugal), was combusted at different temperatures for 2h. We measured Mass Loss (ML per cent), ash colour and CaCO3 content, pH, Electrical Conductivity (EC) and the major cations (Ca2+, Mg2+, K+ and Na+) released from ash slurries created by mixing ash with deionized water. The results showed that ML per cent is higher at all temperatures in Albufeira samples compared to Mas Bassets samples, except at 550??C, and the rate of loss increases faster with temperature than the Mas Bassets samples. At 150??C the ash colour is yellowish, becoming reddish at 200- 250??C and black at 300??C. Above 400??C the ash is grey/white. This thermal degradation is mostly observed in Albufeira litter. The formation of CaCO3 was identified at a lower temperature in Albufeira litter. At temperatures <300??C, pH and EC values are lower, rising at higher temperatures, especially in Albufeira slurries. The concentration of cations at lower temperatures does not differ substantially from the unburned sample except for Mg2+. The cation concentration increases at medium temperatures and decrease at higher temperatures, especially the concentration of divalent cations. The monovalent cations showed a larger concentration at moderate temperatures, mainly in Albufeira ash slurries. The analysis of the Ca:Mg ratio

  10. Repeated summer drought and re-watering during the first growing year of oak (Quercus petraea delay autumn senescence and bud burst in the following spring

    Directory of Open Access Journals (Sweden)

    Kristine Vander Mijnsbrugge

    2016-03-01

    Full Text Available Climate change predicts harsher summer droughts for mid-latitudes in Europe. To enhance our understanding of the putative impacts on forest regeneration, we studied the response of oak seedlings (Quercus petraea to water deficit. Potted seedlings originating from three locally sourced provenances were subjected to two successive drought periods during the first growing season each followed by a plentiful re-watering. Here we describe survival and phenological responses after the second drought treatment, applying general linear mixed modelling. From the 441 drought treated seedlings 189 subsisted with higher chances of survival among smaller plants and among single plants per pot compared to doubles. Remarkably, survival was independent of the provenance, although relatively more plants had died off in two provenances compared to the third one with mean plant height being higher in one provenance and standard deviation of plant height being higher in the other. Timing of leaf senescence was clearly delayed after the severe drought treatment followed by re-watering, with two seedlings per pot showing a lesser retardation compared to single plants. This delay can be interpreted as a compensation time in which plants recover before entering the subsequent developmental process of leaf senescence, although it renders seedlings more vulnerable to early autumn frosts because of the delayed hardening of the shoots. Onset of bud flush in the subsequent spring still showed a significant but small delay in the drought treated group, independent of the number of seedlings per pot, and can be considered as an after effect of the delayed senescence. In both phenological models significant differences among the three provenances were detected independent from the treatment. The only provenance that is believed to be local of origin, displayed the earliest leaf senescence and the latest flushing, suggesting an adaptation to the local maritime climate. This

  11. Do Quercus ilex woodlands undergo abrupt non-linear functional changes in response to human disturbance along a climatic gradient?

    Science.gov (United States)

    Bochet, Esther; García-Fayos, Patricio; José Molina, Maria; Moreno de las Heras, Mariano; Espigares, Tíscar; Nicolau, Jose Manuel; Monleon, Vicente

    2017-04-01

    Theoretical models predict that drylands are particularly prone to suffer critical transitions with abrupt non-linear changes in their structure and functions as a result of the existing complex interactions between climatic fluctuations and human disturbances. However, so far, few studies provide empirical data to validate these models. We aim at determining how holm oak (Quercus ilex) woodlands undergo changes in their functions in response to human disturbance along an aridity gradient (from semi-arid to sub-humid conditions), in eastern Spain. For that purpose, we used (a) remote-sensing estimations of precipitation-use-efficiency (PUE) from enhanced vegetation index (EVI) observations performed in 231x231 m plots of the Moderate Resolution Imaging Spectroradiometer (MODIS); (b) biological and chemical soil parameter determinations (extracellular soil enzyme activity, soil respiration, nutrient cycling processes) from soil sampled in the same plots; (c) vegetation parameter determinations (ratio of functional groups) from vegetation surveys performed in the same plots. We analyzed and compared the shape of the functional change (in terms of PUE and soil and vegetation parameters) in response to human disturbance intensity for our holm oak sites along the aridity gradient. Overall, our results evidenced important differences in the shape of the functional change in response to human disturbance between climatic conditions. Semi-arid areas experienced a more accelerated non-linear decrease with an increasing disturbance intensity than sub-humid ones. The proportion of functional groups (herbaceous vs. woody cover) played a relevant role in the shape of the functional response of the holm oak sites to human disturbance.

  12. Distance and phenology influence pollen gene flow, male reproductive success, and female mate choice in a northern red oak (Quercus rubra L.) seed orchard

    Science.gov (United States)

    Northern red oak is a high-value hardwood used for lumber, furniture and veneer. Intensively managed northern red oak orchards require genetic gain for trait improvement. Data from conifer seed orchards and natural and managed stands of hardwood trees have shed light on the distance over which polle...

  13. Conversion of an oak seed orchard to oak silvopasture

    Science.gov (United States)

    K. Connor; L. Dimov; R. Barlow; M. Smith; E. Kirkland

    2013-01-01

    The potential of hardwood silvopasture has yet to be realized in the Southeastern United States. The decommissioning of the Stauffer Nursery, Opelika, AL, provided the opportunity to intensively research hardwood silvopasture using various oak species. Average crown diameter ranged from 5.9 feet in white oak (Quercus alba) to 10.7 feet in Nuttall oak...

  14. 沈氏栎组培快繁技术的初步研究%Preliminary Study on the Tissue Culture and Rapid Propagation of Quercus shumardi'Shumard Oak'

    Institute of Scientific and Technical Information of China (English)

    丁世民; 李晓娟; 于颖; 宋健云; 郝炎辉

    2012-01-01

    [目的]对沈氏栎组培快繁技术进行初步研究,以期为该物种的快速繁殖和优良性状的保持奠定基础.[方法]以引自北美的沈氏栎(Quercus shumardi’Shumard Oak)为试验材料,从外植体接种试验、试管苗的增殖与生根等技术环节进行了探索,研究沈氏栎瓶内培养技术体系.[结果]用作外植体的理想材料为带腋芽茎段;最佳灭菌方式是用75%的酒精消毒1 min后再用0.1%升汞消毒6 min;试管苗增殖(诱导丛生芽)的最佳培养基为MS +6-BA 0.80 mg/L+NAA 0.45 mg/L;诱导生根的最佳培养基组合为1/2 MS+ NAA 0.40mg/L;瓶苗培养的理想温度为26 ~ 28 ℃.[结论]该研究初步建立了沈氏栎瓶内培养技术体系,同时为该物种的快速繁殖和优良性状的保持奠定基础.%[Objective] To study the rapid tissue culture of Quercus shumardi' shumard Oak',so as to lay foundation for the rapid propagation of this species and maintaining its excellent traits. [ Method] The Quercus shumardi' shumard Oak' from North America was collected as material,the tissue culture and rapid propagation technology was studied from explants inoculation,test-tube proliferation and rooting and so on. [Result] The ideal material of explants was stems with auxiliary bud; the disinfection efficiency of explants was better with 0. 1% HgCl2 for 6 min after the treatment with 75% alcohol for 1 min; the optimum medium for auxiliary buds induction was MS +0. 80 mg/L 6-BA +0.45mg/L NAA; 1/2MS + 0.40 mg/L NAA was suitable for the test tube plantlet rooting; Test-tube seedling raised ideal temperature for 26 -28 ℃. [ Conclusion] The study established a bottle culture system for Quercus shumardi' shumard Oak' and laid foundation for its rapid propagation and maintaining its excellent traits.

  15. Hvem ejer Sherlock Holmes

    DEFF Research Database (Denmark)

    Lauridsen, Palle Schantz

    2013-01-01

    Gennemgang af akterne i en igangværende amerikansk retssag om, hvem der ejer rettighederne til Sherlock Holmes- fortællingerne......Gennemgang af akterne i en igangværende amerikansk retssag om, hvem der ejer rettighederne til Sherlock Holmes- fortællingerne...

  16. Water-use strategies in two co-occurring Mediterranean evergreen oaks: surviving the summer drought.

    Science.gov (United States)

    David, T S; Henriques, M O; Kurz-Besson, C; Nunes, J; Valente, F; Vaz, M; Pereira, J S; Siegwolf, R; Chaves, M M; Gazarini, L C; David, J S

    2007-06-01

    In the Mediterranean evergreen oak woodlands of southern Portugal, the main tree species are Quercus ilex ssp. rotundifolia Lam. (holm oak) and Quercus suber L. (cork oak). We studied a savannah-type woodland where these species coexist, with the aim of better understanding the mechanisms of tree adaptation to seasonal drought. In both species, seasonal variations in transpiration and predawn leaf water potential showed a maximum in spring followed by a decline through the rainless summer and a recovery with autumn rainfall. Although the observed decrease in predawn leaf water potential in summer indicates soil water depletion, trees maintained transpiration rates above 0.7 mm day(-1) during the summer drought. By that time, more than 70% of the transpired water was being taken from groundwater sources. The daily fluctuations in soil water content suggest that some root uptake of groundwater was mediated through the upper soil layers by hydraulic lift. During the dry season, Q. ilex maintained higher predawn leaf water potentials, canopy conductances and transpiration rates than Q. suber. The higher water status of Q. ilex was likely associated with their deeper root systems compared with Q. suber. Whole-tree hydraulic conductance and minimum midday leaf water potential were lower in Q. ilex, indicating that Q. ilex was more tolerant to drought than Q. suber. Overall, Q. ilex seemed to have more effective drought avoidance and drought tolerance mechanisms than Q. suber.

  17. [Tree-ring growth responses of Mongolian oak (Quercus mongolica) to climate change in southern northeast: a case study in Qianshan Mountains].

    Science.gov (United States)

    Teng, Li; Xing-Yuan, He; Zhen-Ju, Chen

    2014-07-01

    Mongolian oak is one of the most important broad-leaved tree species in forests, Northeast China. Based on the methodology of dendrochronology, the variations of tree ring radial growth of Mongolian oak in Qianshan Mountains, south of Northeast China, were analyzed. Combined with the temperature and precipitation data from meteorological stations since 1951, the relationships between standardized tree ring width chronology and main climatic factors were analyzed. In this region, the precipitation between April and July of the current year had an significant relationship with the tree ring width of Mongolian oak, and was the main factor limiting the radial growth. The extreme maximum temperature of May was also a key factor influencing the tree ring width, which had a significant on the tree ring width of Mongolian oak. The precipitation in April had a significant and stable relationship with the growth of Mongolian oak since the 1950s. The 'divergence problem' was found in the study area, which the sensitivity of tree growth to summer temperature reduced since the 1980s. The tree growth response to temperature showed a seasonal change from summer to spring.

  18. 2-DE proteomics analysis of drought treated seedlings of Quercus ilex supports a root active strategy for metabolic adaptation in response to water shortage.

    Science.gov (United States)

    Simova-Stoilova, Lyudmila P; Romero-Rodríguez, Maria C; Sánchez-Lucas, Rosa; Navarro-Cerrillo, Rafael M; Medina-Aunon, J Alberto; Jorrín-Novo, Jesús V

    2015-01-01

    Holm oak is a dominant tree in the western Mediterranean region. Despite being well adapted to dry hot climate, drought is the main cause of mortality post-transplanting in reforestation programs. An active response to drought is critical for tree establishment and survival. Applying a gel-based proteomic approach, dynamic changes in root proteins of drought treated Quercus ilex subsp. Ballota [Desf.] Samp. seedlings were followed. Water stress was applied on 20 day-old holm oak plantlets by water limitation for a period of 10 and 20 days, each followed by 10 days of recovery. Stress was monitored by changes in water status, plant growth, and electrolyte leakage. Contrary to leaves, holm oak roots responded readily to water shortage at physiological level by growth inhibition, changes in water status and membrane stability. Root proteins were extracted using trichloroacetate/acetone/phenol protocol and separated by two-dimensional electrophoresis. Coomassie colloidal stained gel images were analyzed and spot intensity data subjected to multivariate statistical analysis. Selected consistent spots in three biological replicas, presenting significant changes under stress, were subjected to MALDI-TOF mass spectrometry (peptide mass fingerprinting and MS/MS). For protein identification, combined search was performed with MASCOT search engine over NCBInr Viridiplantae and Uniprot databases. Data are available via ProteomeXchange with identifier PXD002484. Identified proteins were classified into functional groups: metabolism, protein biosynthesis and proteolysis, defense against biotic stress, cellular protection against abiotic stress, intracellular transport. Several enzymes of the carbohydrate metabolism decreased in abundance in roots under drought stress while some related to ATP synthesis and secondary metabolism increased. Results point at active metabolic adjustment and mobilization of the defense system in roots to actively counteract drought stress.

  19. 2-DE proteomics analysis of drought treated seedlings of Quercus ilex supports a root active strategy for metabolic adaptation in response to water shortage

    Directory of Open Access Journals (Sweden)

    Lyudmila Petrova Simova-Stoilova

    2015-08-01

    Full Text Available Holm oak is a dominant tree in the western Mediterranean region. Despite being well adapted to dry hot climate, drought is the main cause of mortality post-transplanting in reforestation programs. An active response to drought is critical for tree establishment and survival. Applying a gel-based proteomic approach, the dynamic changes in root proteins of drought treated Quercus ilex subsp. Ballota [Desf.] Samp. seedlings were followed. Water stress was applied on 20 day-old holm oak plantlets by water limitation for a period of 10 and 20 days, each followed by 10 days of recovery. Stress was monitored by changes in water status, plant growth and electrolyte leakage. Contrary to leaves, holm oak roots responded readily to water shortage at physiological level by growth inhibition, changes in water status and membrane stability. Root proteins were extracted using trichloroacetate/acetone/phenol protocol and subjected to two-dimensional electrophoresis. Coomassie colloidal stained gel images were analysed and spot intensity data subjected to multivariate statistical analysis. Selected consistent spots in the three biological replicas, presenting significant changes under stress, were subjected to MALDI-TOF mass spectrometry (peptide mass fingerprinting and MS/MS. For protein identification, combined search was performed with MASCOT search engine over NCBInr Viridiplantae and Uniprot databases. Data are available via ProteomeXchange with identifier PXD002484. Identified proteins were classified into functional groups: metabolism, protein biosynthesis and proteolysis, defence against biotic stress, cellular protection against abiotic stress, intracellular transport. Several enzymes of the carbohydrate metabolism decreased in abundance in roots under drought stress while some related to ATP synthesis and secondary metabolism increased. Results point at active metabolic adjustment and mobilization of the defence system in roots to actively counteract

  20. Sherlock Holmes: scientific detective.

    Science.gov (United States)

    Snyder, Laura J

    2004-09-01

    Sherlock Holmes was intended by his creator, Arthur Conan Doyle, to be a 'scientific detective'. Conan Doyle criticized his predecessor Edgar Allan Poe for giving his creation - Inspector Dupin - only the 'illusion' of scientific method. Conan Doyle believed that he had succeeded where Poe had failed; thus, he has Watson remark that Holmes has 'brought detection as near an exact science as it will ever be brought into the world.' By examining Holmes' methods, it becomes clear that Conan Doyle modelled them on certain images of science that were popular in mid- to late-19th century Britain. Contrary to a common view, it is also evident that rather than being responsible for the invention of forensic science, the creation of Holmes was influenced by the early development of it.

  1. Sherlock Holmes and anaesthesia.

    Science.gov (United States)

    Maltby, J R

    1988-01-01

    Sir Arthur Conan Doyle's first Sherlock Holmes adventure, A Study in Scarlet, was published 100 years ago. Between 1887 and 1927 he wrote 56 short stories and four novels about his fictional detective. Episodes in the adventures which relate to anaesthetic drugs are described. Use of the drugs was criminal in the case of chloroform, opium, and curare; therapeutic in the case of morphine; and recreational when Holmes himself used cocaine.

  2. HEAVY METAL ANALYSIS IN RED OAK (QUERCUS RUBRA POPULATIONS FROM A MINING REGION IN NORTHERN ONTARIO (CANADA: EFFECT OF SOIL LIMING AND ANALYSIS OF GENETIC VARIATION

    Directory of Open Access Journals (Sweden)

    Anh Tran

    2014-01-01

    Full Text Available Understanding the dynamic of metals in soil and plants and population diversity in Northern Ontario is essential in determining progress toward ecosystem sustainability in reclaimed sites. The objectives of the present study were to assess the levels of metal content in soils and their accumulation in red oak plants from limed and unlimed sites. Genetic variation in red oak populations from the Northern Ontario region was also analyzed. The levels of soil acidity was lower in limed areas compared to un limed sites, an indication of the prolonged beneficial effect of liming 20 to 30 years ago on soil toxicity. The levels of total metals were very high for most elements, but the proportion of metals that were bio available and readily available to plants was very small. The enrichment factors were16.78, 4.98 and 2.94 for total arsenic, copper and nickel, respectively. The Translocation Factor (TF values for available metals from soil to branches were high. There was more metal accumulation in leaves compared to branches. The degrees of genetic variability in red oak populations from limed and unlimed areas were compared using ISSR markers. The levels of polymorphic loci were moderate to high ranging from 44 to 65%. There were no significant differences in polymorphisms between areas that were limed and unlimed. Overall the red oak populations in stressed areas in Northern Ontario are sustainable.

  3. [Effects of fire recurrence on fire behaviour in cork oak woodlands (Quercus suber L.) and Mediterranean shrublands over the last fifty years].

    Science.gov (United States)

    Schaffhauser, Alice; Pimont, François; Curt, Thomas; Cassagne, Nathalie; Dupuy, Jean-Luc; Tatoni, Thierry

    2015-12-01

    Past fire recurrence impacts the vegetation structure, and it is consequently hypothesized to alter its future fire behaviour. We examined the fire behaviour in shrubland-forest mosaics of southeastern France, which were organized along a range of fire frequency (0 to 3-4 fires along the past 50 years) and had different time intervals between fires. The mosaic was dominated by Quercus suber L. and Erica-Cistus shrubland communities. We described the vegetation structure through measurements of tree height, base of tree crown or shrub layer, mean diameter, cover, plant water content and bulk density. We used the physical model Firetec to simulate the fire behaviour. Fire intensity, fire spread, plant water content and biomass loss varied significantly according to fire recurrence and vegetation structure, mainly linked to the time since the last fire, then the number of fires. These results confirm that past fire recurrence affects future fire behaviour, with multi-layered vegetation (particularly high shrublands) producing more intense fires, contrary to submature Quercus woodlands that have not burnt since 1959 and that are unlikely to reburn. Further simulations, with more vegetation scenes according to shrub and canopy covers, will complete this study in order to discuss the fire propagation risk in heterogeneous vegetation, particularly in the Mediterranean area, with a view to a local management of these ecosystems.

  4. Effects of a low severity prescribed fire on water-soluble elements in ash from a cork oak (Quercus suber) forest located in the northeast of the Iberian Peninsula

    Science.gov (United States)

    Pereira, P.; beda, X.; Martin, D.; Mataix-Solera, J.; Guerrero, C.

    2011-01-01

    Wildfire is the major disturbance in Mediterranean forests. Prescribed fire can be an alternative to reduce the amount of fuel and hence decrease the wildfire risk. However the effects of prescribed fire must be studied, especially on ash properties, because ash is an important nutrient source for ecosystem recovery. The aim of this study is to determine the effects of a low severity prescribed fire on water-soluble elements in ash including pH, electrical conductivity (EC), calcium (Ca), magnesium (Mg), sodium (Na), potassium (K), aluminum (Al), manganese (Mn), iron (Fe), zinc (Zn), silica (SiO2) and total sulphur (TS). A prescribed fire was conducted in a cork oak (Quercus suber) (Q.S) forest located in the northeast part of the Iberian Peninsula. Samples were collected from a flat plot of 40??70m mainly composed of Q.S and Quercus robur (Q.R) trees. In order to understand the effects of the prescribed fire on the soluble elements in ash, we conducted our data analysis on three data groups: all samples, only Q.S samples and only Q.R samples. All three sample groups exhibited a significant increase in pH, EC (pwater-soluble Ca, Mg, Na, SiO2 and TS and a decrease in water-soluble Mn, Fe and Zn. Differences were identified between oak species for water-soluble K, Al and Fe. In Q.S samples we registered a significant increase in the first two elements pwater-soluble K and Al and a significant decrease in water-soluble Fe (psamples, that at some points burned with higher severity. The increase of pH, EC, Ca, Mg, Na and K will improve soil fertility, mainly in the study area where soils are acidic. The application of this low severity prescribed fire will improve soil nutrient status without causing soil degradation and thus is considered to be a good management strategy. ?? 2010 Elsevier Inc.

  5. Facilitation of Quercus ilex recruitment by shrubs in Mediterranean open woodlands

    NARCIS (Netherlands)

    Smit, Christian; den Ouden, Jan; Diaz, Mario

    2008-01-01

    Question: Insufficient tree regeneration threatens the long-term persistence of biodiverse Mediterranean open oak woodlands. Could shrubs, scarce due to decades of management ( clearing and ploughing), facilitate holm oak recruitment at both acorn and seedling stages? Location: Open oak woodlands in

  6. Pollen gene flow, male reproductive success, and genetic correlations among offspring in a northern red oak (Quercus rubra L.) seed orchard.

    Science.gov (United States)

    Alexander, Lisa; Woeste, Keith

    2017-01-01

    Northern red oak is a high-value hardwood used for lumber, furniture and veneer. Intensively managed northern red oak seed orchards are required to obtain genetic gain for trait improvement. Data from conifer seed orchards and natural and managed stands of hardwood trees have shed light on the distance over which pollen can move, and underscore the need for managerial attention to seed orchard design, placement, and maintenance. We used eleven microsatellite markers to investigate pollen gene flow, female mate choice, and male reproductive success in a clonal seed orchard of northern red oak based on paternity analysis of seed orchard offspring in progeny tests. Nearly all (93%) offspring were sired by a male parent within the seed orchard. The mean number of male parents per year was 69.5, or 47.6% of all clones in the seed orchard. Female clones in the early phenology group had more offspring sired from extra-orchard pollen (13%) than clones in the intermediate (5%) and late (1%) phenology groups. Distance was the largest influence on pollination success, and pollination occurred most often by male trees in the same subline as the maternal tree. Males in the early phenology group sired more offspring overall in the progeny pool and more offspring per mother tree than males in the intermediate or late phenology groups. Average genetic correlations among all OP progeny ranged between 0.2557 and 0.3529 with a mean of 0.28±0.01. The importance of progeny test genotyping for northern red oak improvement likely is increasing with the demand for improved varieties. The current study demonstrated the feasibility of post hoc assembly of full-sib families for genetic analysis.

  7. Effects of fertilization on the vascular ground vegetation of European beech (Fagus sylvatica L.) and sessile oak (Quercus petraea (Matt.) Lieb.) stands

    OpenAIRE

    Misson, Laurent; Gaëtan Du Bus De Warnaffe,; Jonard, Mathieu

    2001-01-01

    International audience; The objective of this study was to assess the effects of base cation (Ca, Mg, K) and phosphorous (P) fertilization on the vascular ground vegetation in mature European beech and sessile oak stands located on acid brown soils. Two types of treatment were applied next to control plots (dolomite lime, dolomite lime + natural phosphate + potassium sulphate). Specific richness, total cover (% ), equitability coefficient as well as the Ecological Group of the ground vegetati...

  8. Pollen gene flow, male reproductive success, and genetic correlations among offspring in a northern red oak (Quercus rubra L.) seed orchard

    Science.gov (United States)

    Woeste, Keith

    2017-01-01

    Northern red oak is a high-value hardwood used for lumber, furniture and veneer. Intensively managed northern red oak seed orchards are required to obtain genetic gain for trait improvement. Data from conifer seed orchards and natural and managed stands of hardwood trees have shed light on the distance over which pollen can move, and underscore the need for managerial attention to seed orchard design, placement, and maintenance. We used eleven microsatellite markers to investigate pollen gene flow, female mate choice, and male reproductive success in a clonal seed orchard of northern red oak based on paternity analysis of seed orchard offspring in progeny tests. Nearly all (93%) offspring were sired by a male parent within the seed orchard. The mean number of male parents per year was 69.5, or 47.6% of all clones in the seed orchard. Female clones in the early phenology group had more offspring sired from extra-orchard pollen (13%) than clones in the intermediate (5%) and late (1%) phenology groups. Distance was the largest influence on pollination success, and pollination occurred most often by male trees in the same subline as the maternal tree. Males in the early phenology group sired more offspring overall in the progeny pool and more offspring per mother tree than males in the intermediate or late phenology groups. Average genetic correlations among all OP progeny ranged between 0.2557 and 0.3529 with a mean of 0.28±0.01. The importance of progeny test genotyping for northern red oak improvement likely is increasing with the demand for improved varieties. The current study demonstrated the feasibility of post hoc assembly of full-sib families for genetic analysis. PMID:28166543

  9. Tree Species Richness and Stand Productivity in Low-Density Cluster Plantings with Oaks (Quercus robur L. and Q. petraea (Mattuschka Liebl.

    Directory of Open Access Journals (Sweden)

    Christian Kuehne

    2013-08-01

    Full Text Available Low density plantings complemented by natural regeneration is an increasingly common reforestation technique to ensure growth of a sufficient number of trees from desired species while maintaining natural processes such as succession. One such form of low density planting that aims at lowering establishment costs—oak clusters—has been developed as an alternative to row planting since the 1980s in central Europe. However, whether cluster planting provides higher species richness and productivity than high density row planting has not previously been analyzed. Here, we compare tree species richness and productivity (measured as stand basal area between oak cluster plantings and conventional row planting in young (10–26 years old forest stands at seven study sites in Germany. Tree species richness was significantly higher in cluster plantings than in row plantings, whereas total basal areas were comparable. Naturally regenerated trees contributed on average to 43% of total stand basal area in cluster plantings, which was significantly higher than in row plantings. Total stand basal area in cluster planting was significantly related to the density of naturally regenerated trees. In turn, tree species diversity, density and basal area of naturally regenerated trees were increased with the size of unplanted area between clusters. Our results demonstrate that the admixture of naturally regenerated, early and mid-successional tree species compensates for a possible loss in productivity from planting fewer oaks. Low density cluster plantings can offer significant environmental benefits, at least for the first few decades of stand development, without compromising productivity.

  10. Identification of Quercus agrifolia (coast live oak resistant to the invasive pathogen Phytophthora ramorum in native stands using Fourier-transform infrared (FT-IR spectroscopy

    Directory of Open Access Journals (Sweden)

    Anna Olivia Conrad

    2014-10-01

    Full Text Available Over the last two decades coast live oak (CLO dominance in many California coastal ecosystems has been threatened by the alien invasive pathogen Phytophthora ramorum, the causal agent of sudden oak death. In spite of high infection and mortality rates in some areas, the presence of apparently resistant trees has been observed, including trees that become infected but recover over time. However, identifying resistant trees based on recovery alone can take many years. The objective of this study was to determine if Fourier-transform infrared (FT-IR spectroscopy, a chemical fingerprinting technique, can be used to identify CLO resistant to P. ramorum prior to infection. Soft independent modeling of class analogy identified spectral regions that differed between resistant and susceptible trees. Regions most useful for discrimination were associated with carbonyl group vibrations. Additionally, concentrations of two putative phenolic biomarkers of resistance were predicted using partial least squares regression; > 99% of the variation was explained by this analysis. This study demonstrates that chemical fingerprinting can be used to identify resistance in a natural population of forest trees prior to infection with a pathogen. FT-IR spectroscopy may be a useful approach for managing forests impacted by sudden oak death, as well as in other situations where emerging or existing forest pests and diseases are of concern.

  11. Holms zagovoril po-nemetski

    Index Scriptorium Estoniae

    2007-01-01

    Moskva briti saatkonna õuel avati skulptuurigrupp A. C. Doyle'i loodud kirjanduslike kujude Sherlock Holmes'i ja dr. Watsoniga. Kohal viibis ka Venemaa kuulsaim Holmes'i kehastaja Vassili Livanov perega ja Watsoni kehastaja Vitali Solomini lesk

  12. Holms zagovoril po-nemetski

    Index Scriptorium Estoniae

    2007-01-01

    Moskva briti saatkonna õuel avati skulptuurigrupp A. C. Doyle'i loodud kirjanduslike kujude Sherlock Holmes'i ja dr. Watsoniga. Kohal viibis ka Venemaa kuulsaim Holmes'i kehastaja Vassili Livanov perega ja Watsoni kehastaja Vitali Solomini lesk

  13. Exposition of cork oak roots to cryptogein reduced the Infection by Phytophtora cinnamomi

    OpenAIRE

    Maia, I.; Medeira, C.; Candeias, I.; A.C. Moreira; Melo, Eduardo P.; Cravador, A.

    2009-01-01

    The oomycete P. cinnamomi has been described as strong contributing factor to the decline of cork oak and holm oak stands occurring in the Iberian Peninsula. There are no eradication methods available against this pathogen.

  14. Sherlock Holmes i arkiverne

    DEFF Research Database (Denmark)

    Lauridsen, Palle Schantz

    2014-01-01

    Er præsentation af, hvordan arkiver og museer har været af afgørende betydning for, at det overhovedet kunne lade sig gøre for forfatteren at finde materiale til bogen "Sherlock Holmes i Danmark".......Er præsentation af, hvordan arkiver og museer har været af afgørende betydning for, at det overhovedet kunne lade sig gøre for forfatteren at finde materiale til bogen "Sherlock Holmes i Danmark"....

  15. Did the late spring frost in 2007 and 2011 affect tree-ring width and earlywood vessel size in Pedunculate oak ( Quercus robur) in northern Poland?

    Science.gov (United States)

    Puchałka, Radosław; Koprowski, Marcin; Przybylak, Julia; Przybylak, Rajmund; Dąbrowski, Henryk P.

    2016-08-01

    Trees are sensitive to extreme weather and environmental conditions. This sensitivity is visible in tree-ring widths and cell structure. In our study, we hypothesized that the sudden frost noted at the beginning of May in both 2007 and 2011 affected cambial activity and, consequently, the number and size of vessels in the tree rings. It was decided to test this hypothesis after damage to leaves was observed. The applied response function model did not show any significant relationships between spring temperature and growth. However, this method uses average values for long periods and sometimes misses the short-term effects. This is why we decided to study each ring separately, comparing them with rings unaffected by the late frost. Our study showed that the short-term effect of sudden frost in late spring did not affect tree rings and selected cell parameters. The most likely reasons for this are (i) cambial activity producing the earlywood vessels before the occurrence of the observed leaf damage, (ii) the forest micro-climate protecting the trees from the harsh frost and (iii) the temperature decline being too short-lived an event to affect the oaks. On the other hand, the visible damage may be occasional and not affect cambium activity and tree vitality at all. We conclude that oak is well-adapted to this phenomenon.

  16. THE EFFECT OF THE HEAT TREATMENT OF SESSILE OAK WOOD (Quercus petrea L. FROM YOUNG TREES ON THE PROPERTIES OF PANELS WITH TRANSVERSAL GRAIN

    Directory of Open Access Journals (Sweden)

    Noemi MARTON

    2012-06-01

    Full Text Available Sessile oak from young trees represents asecondary resource with potential for superiorapplications in furniture panels providing theirdimensional stability to variations of relative airhumidity is reduced. A possibility to improve thisproperty was examined in this paper, by thermaltreatment of the raw material before manufacturingdecorative furniture panels with transversal grain.Panels with crosscut grain were manufactured fromboth heat treated and untreated wood and theirproperties were compared: dimensional changewith climate, the moisture content at equilibrium, theabsolute density, colour and their MOE and MOR.The results have shown that the thermaltreatment at 130ºC for 2h of sessile oak from youngtrees has improved the dimensional stability and theequilibrium moisture content of the panels and didnot impair their mechanical strength. The colour gotslightly darker and density had an almost negligibledecrease by the heat treatment. Attractive bydesign, because of their grain orientation, but in thisway subjected to axial stresses perpendicular to thegrain, the panels could be used in furnitureapplications where the bending stresses are notcritical.

  17. Seasonal variation of leaf wax n-alkane production and δ(2)H values from the evergreen oak tree, Quercus agrifolia.

    Science.gov (United States)

    Sachse, Dirk; Dawson, Todd E; Kahmen, Ansgar

    2015-01-01

    In order to understand the timing of leaf wax synthesis in higher plants, we analysed the variability in leaf wax n-alkane concentration, composition (expressed as average chain length (ACL)), and δ(2)Hwax values as well as plant source water δ(2)H values (xylem and leaf water) in the evergreen tree Quercus agrifolia over a period of 9 months, beginning with leaf flush. We identified three distinct periods of leaf development with the first month following leaf flush being characterized by de novo synthesis and possibly removal of n-alkanes. During the following 3 months, n-alkane concentrations increased sevenfold and δ(2)Hwax and ACL values increased, suggesting this period was the major leaf wax n-alkane formation period. During the remaining 4 months of the experiment, stable values suggest cessation of leaf wax n-alkane formation. We find that n-alkane synthesis in Q. agrifolia takes place over 4 months, substantially longer than that observed for deciduous trees.

  18. The Hibernation of the oak Mildew

    NARCIS (Netherlands)

    Kerling, L.C.P.

    1966-01-01

    The oak mildew invaded Western Europa in the years 1908 and 1909. Since then this parasite, Microsphaera alphitoides Griff. & Maubl. (syn. M. quercina (Schw.) Burr.) has occurred regularly in the Netherlands on oak seedlings and oak coppice, mainly Quercus pedunculata Ehr. (syn. Q. robur L. ). After

  19. Oaks belowground: mycorrhizas, truffles, and small mammals

    Science.gov (United States)

    Jonathan Frank; Seth Barry; Joseph Madden; Darlene Southworth

    2008-01-01

    Oaks depend on hidden diversity belowground. Oregon white oaks (Quercus garryana) form ectomycorrhizas with more than 40 species of fungi at a 25-ha site. Several of the most common oak mycorrhizal fungi form hypogeous fruiting bodies or truffles in the upper layer of mineral soil. We collected 18 species of truffles associated with Oregon white...

  20. Vegetative propagation of Quercus suber L. by somatic embryogenesis. I. Factors affecting the induction in leaves from mature cork oak trees.

    Science.gov (United States)

    Hernández, I; Celestino, C; Toribio, M

    2003-04-01

    Somatic embryogenesis was induced in expanding leaves from epicormic shoots forced to sprout from segments of branches collected from several hundred-year-old cork oak trees. Following a basic protocol previously defined for leaves taken from seedlings of this species, several factors were studied to improve the response. The induction frequency was significantly higher when the length of exposure to growth regulators was increased from 7 to 30 days. The combined application of NAA and BAP was essential for induction. Although both regulators had a very significant influence, their interaction was not significant, suggesting independent roles. Leaf size had a crucial effect, because beyond a certain threshold, embryogenesis could not be obtained. Embryogenic lines were maintained via repetitive embryogenesis on hormone-free medium for more than 2 years.

  1. HOLMES I DANSKE TEGNESERIER

    DEFF Research Database (Denmark)

    Lauridsen, Palle Schantz

    2017-01-01

    En mediehistorisk og -analytisk undersøgelse af fremstillingen af Sherlock Holmes-karakteren og -universet i tegneserier udgivet i Danmark. Del 1 omhandler en upåagtet række søndagsstriber, Storm P. tegnede for Ekstrabladet i 1910-11. De hører til blandt Danmarks allerførste tegneserier...

  2. Variation in the radial patterns of sap flux density in pubescent oak (Quercus pubescens) and its implications for tree and stand transpiration measurements.

    Science.gov (United States)

    Poyatos, Rafael; Cermák, Jan; Llorens, Pilar

    2007-04-01

    Radial variation in sap flux density across the sapwood was assessed by the heat field deformation method in several trees of Quercus pubescens Wild., a ring-porous species. Sapwood depths were delimited by identifying the point of zero flow in radial patterns of sap flow, yielding tree sapwood areas that were 1.5-2 times larger than assumed based on visual examinations of wood cores. The patterns of sap flow varied both among trees and diurnally. Rates of sap flow were higher close to the cambium, although there was a significant contribution from the inner sapwood, which was greater (up to 60% of total flow) during the early morning and late in the day. Accordingly, the normalized difference between outer and inner sapwood flow was stable during the middle of the day, but showed a general decline in the afternoon. The distribution of sap flux density across the sapwood allowed us to derive correction coefficients for single-point heat dissipation sap flow measurements. We used daytime-averaged coefficients that depended on the particular shape of the radial profile and ranged between 0.45 and 1.28. Stand transpiration calculated using the new method of estimating sapwood areas and the radial correction coefficients was similar to (Year 2003), or about 25% higher than (Year 2004), previous uncorrected values, and was 20-30% of reference evapotranspiration. We demonstrated how inaccuracies in determining sapwood depths and mean sap flux density across the sapwood of ring-porous species could affect tree and stand transpiration estimates.

  3. Cork oak woodlands patchiness

    DEFF Research Database (Denmark)

    Costa, Augusta; Madeira, Manuel; Plieninger, Tobias

    2014-01-01

    The cork oak (Quercus suber L.) woodlands of the agroforestry landscapes of Southwestern Iberia are undergoing drastic change due to severe natural and anthropogenic disturbances. These may eventually result in woodland loss or deforestation, the final step of an ongoing process of woodland degra...

  4. Fragmentation patterns of evergreen oak woodlands in Southwestern Iberia

    DEFF Research Database (Denmark)

    Costa, A.; Madeira, M.; Lima Santos, J.

    2014-01-01

    Mediterranean evergreen oak woodlands (composed of Quercus suber L. and Quercus rotundifolia Lam.) are becoming increasingly fragmented in the human-modified landscapes of Southwestern Portugal and Spain. Previous studies have largely neglected to assess the spatial changes of oak woodlands in re...

  5. Allocation of 14C assimilated in late spring to tissue and biochemical stem components of cork oak (Quercus suber L.) over the seasons.

    Science.gov (United States)

    Aguado, Pedro L; Curt, M Dolores; Pereira, Helena; Fernández, Jesús

    2012-03-01

    Carbon distribution in the stem of 2-year-old cork oak plants was studied by (14)CO(2) pulse labeling in late spring in order to trace the allocation of photoassimilates to tissue and biochemical stem components of cork oak. The fate of (14)C photoassimilated carbon was followed during two periods: the first 72 h (short-term study) and the first 52 weeks (long-term study) after the (14)CO(2) photosynthetic assimilation. The results showed that (14)C allocation to stem tissues was dependent on the time passed since photoassimilation and on the season of the year. In the first 3 h all (14)C was found in the polar extractives. After 3 h, it started to be allocated to other stem fractions. In 1 day, (14)C was allocated mostly to vascular cambium and, to a lesser extent, to primary phloem; no presence of (14)C was recorded for the periderm. However, translocation of (14)C to phellem was observed from 1 week after (14)CO(2) pulse labeling. The phellogen was not completely active in its entire circumference at labeling, unlike the vascular cambium; this was the tissue that accumulated most photoassimilated (14)C at the earliest sampling. The fraction of leaf-assimilated (14)C that was used by the stem peaked at 57% 1 week after (14)CO(2) plant exposure. The time lag between C photoassimilation and suberin accumulation was ∼8 h, but the most active period for suberin accumulation was between 3 and 7 days. Suberin, which represented only 1.77% of the stem weight, acted as a highly effective sink for the carbon photoassimilated in late spring since suberin specific radioactivity was much higher than for any other stem component as early as only 1 week after (14)C plant labeling. This trend was maintained throughout the whole experiment. The examination of microautoradiographs taken over 1 year provided a new method for quantifying xylem growth. Using this approach it was found that there was more secondary xylem growth in late spring than in other times of the year

  6. Evaluation of spectral light management on growth of container-grown willow oak, nuttall oak and summer red maple

    Science.gov (United States)

    Plant response to blue, red, gray or black shade cloth was evaluated with willow oak (Quercus phellos L.), Nuttall oak (Quercus nuttallii Palmer, Nuttall) and Summer Red maple (Acer rubrum L. ‘Summer Red’) liners. Light transmitted through the colored shade cloth had no influence on germination of ...

  7. Comparing the impact of climate variables on healthy and declined masses of oak (Quercus brantti Lindl in the “Khorram Abad” city

    Directory of Open Access Journals (Sweden)

    Ladan Poursartip

    2017-02-01

    Full Text Available In this study, using dendroclimatology (a branch of the science of dendrochronology, the impact of climate variables on normal masses and declined oak in the city “Khorram Abad” was studied. After the selection of 12 samples from healthy trees and 12 trees from declined ones, breast height (1.30 m discs were prepared. Then, the samples were scanned and ring width was measured using Corel Draw software. Using TSAP and ARSTAN softwares, cross dating between samples were done and chronology was prepared respectively. From the nearest meteorological station, rainfall and temperature data obtained and their effects on growth rings of trees was investigated using Pearson's correlation coefficient. The results of this study showed that both chronologies were equally affected by climatic factors. The temperature during the growing season and before it has a similar effect on both chronologies. Until 2010, the growth of trees is almost the same, but from this year onwards, curve of declined trees identified a drop in growth, probably due to the impact of pests and the deterioration in the trees. From this year onwards, despite the significant increase in precipitation, compared with previous years, increasing growth of the declined trees was not found and this means that due to the factors causing deterioration and thus reduce the activity of cambium, the trees have lost their re-growth and even with the improvement of environmental conditions, there was no possibility of resuming growth.

  8. Oak (Quercus frainetto Ten. Honeydew Honey—Approach to Screening of Volatile Organic Composition and Antioxidant Capacity (DPPH and FRAP Assay

    Directory of Open Access Journals (Sweden)

    Igor Jerković

    2010-05-01

    Full Text Available Two samples of oak honeydew honey were investigated. Headspace solid-phase microextraction (HS-SPME combined with GC and GC/MS enabled identification of the most volatile organic headspace compounds being dominated by terpenes(mainly cis- and trans-linalool oxides. The volatile and less-volatile organic composition of the samples was obtained by ultrasonic assisted extraction (USE with two solvents (1:2 (v/v pentane -diethyl ether mixture and dichloromethane followed by GC and GC/MS analysis. Shikimic pathway derivatives are of particular interest with respect to the botanical origin of honey and the most abundant was phenylacetic acid (up to 16.4%. Antiradical activity (DPPH assay of the honeydew samples was 4.5 and 5.1 mmol TEAC/kg. Ultrasonic solvent extracts showed several dozen times higher antiradical capacity in comparison to the honeydew. Antioxidant capacity (FRAP assay of honeydew samples was 4.8 and 16.1 mmol Fe2+/kg, while the solvent mixture extracts showed antioxidant activity of 374.5 and 955.9 Fe2+/kg, respectively, and the dichloromethane extracts 127.3 and 101.5 mmol Fe2+/kg.

  9. Oak (Quercus frainetto Ten.) honeydew honey--approach to screening of volatile organic composition and antioxidant capacity (DPPH and FRAP assay).

    Science.gov (United States)

    Jerković, Igor; Marijanović, Zvonimir

    2010-05-25

    Two samples of oak honeydew honey were investigated. Headspace solid-phase microextraction (HS-SPME) combined with GC and GC/MS enabled identification of the most volatile organic headspace compounds being dominated by terpenes(mainly cis- and trans-linalool oxides). The volatile and less-volatile organic composition of the samples was obtained by ultrasonic assisted extraction (USE) with two solvents (1:2 (v/v) pentane -diethyl ether mixture and dichloromethane) followed by GC and GC/MS analysis. Shikimic pathway derivatives are of particular interest with respect to the botanical origin of honey and the most abundant was phenylacetic acid (up to 16.4%). Antiradical activity (DPPH assay) of the honeydew samples was 4.5 and 5.1 mmol TEAC/kg. Ultrasonic solvent extracts showed several dozen times higher antiradical capacity in comparison to the honeydew. Antioxidant capacity (FRAP assay) of honeydew samples was 4.8 and 16.1 mmol Fe(2+)/kg, while the solvent mixture extracts showed antioxidant activity of 374.5 and 955.9 Fe(2+)/kg, respectively, and the dichloromethane extracts 127.3 and 101.5 mmol Fe(2+)/kg.

  10. Purification of a new isoform of laccase from a Marasmius quercophilus strain isolated from a cork oak litter (Quercus suber L).

    Science.gov (United States)

    Farnet, A M; Criquet, S; Pocachard, E; Gil, G; Ferre, E

    2002-01-01

    A new isoform of laccase from Marasmius quercophilus is described in this study. The strain of this white-rot fungus was isolated for the first time on a cork oak litter. This isoform exhibited certain common properties of laccases (a molecular weight of 65 Kda, an optimum pH of 6.2 with syringaldazine). But this laccase has also particularly novel features: the best activity measured was observed at high temperatures (80 C) and this isoform was not inhibited with EDTA. Furthermore, this induced laccase was able to transform most of the aromatic compounds tested without the addition of mediators to the reaction mixture, and the transformation of certain chlorophenols (2-chlorophenol and 2,4-dichlorophenol) by a laccase isoform from M. quercophilus is reported here for the first time. We also demonstrate the importance of 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonate) (ABTS) as a mediator since it allowed veratryl alcohol and p-hydroxybenzoic acid transformation. Moreover, new products of transformation were observed using the combination of ABTS with this isoform of laccase.

  11. The HOLMES Experiment

    Science.gov (United States)

    Faverzani, M.; Alpert, B.; Backer, D.; Bennet, D.; Biasotti, M.; Brofferio, C.; Ceriale, V.; Ceruti, G.; Corsini, D.; Day, P. K.; De Gerone, M.; Dressler, R.; Ferri, E.; Fowler, J.; Fumagalli, E.; Gard, J.; Gatti, F.; Giachero, A.; Hays-Wehle, J.; Heinitz, S.; Hilton, G.; Köster, U.; Lusignoli, M.; Maino, M.; Mates, J.; Nisi, S.; Nizzolo, R.; Nucciotti, A.; Orlando, A.; Parodi, L.; Pessina, G.; Pizzigoni, G.; Puiu, A.; Ragazzi, S.; Reintsema, C.; Ribeiro-Gomez, M.; Schmidt, D.; Schuman, D.; Siccardi, F.; Sisti, M.; Swetz, D.; Terranova, F.; Ullom, J.; Vale, L.

    2016-08-01

    The determination of the neutrino mass is an open issue in modern particle physics and astrophysics. The direct mass measurement is the only theory-unrelated experimental tool capable to probe such quantity. The HOLMES experiment will measure the end-point energy of the electron capture decay of ^{163}Ho, aiming at a statistical sensitivity on the neutrino mass around 1 eV/c^2. In order to acquire the large needed statistics by keeping the pile-up contribution as low as possible, 1000 transition edge sensors will be readout simultaneously with the frequency domain readout, a multiplexing technique where the multiplex factor is only limited by the bandwidth of the available commercial fast digitizers. We outline here the HOLMES project with its technical challenges, and its status and perspectives.

  12. The effect of seed size variation in Quercus pacifica on seedling establishment and growth

    Science.gov (United States)

    Mario B. Pesendorfer

    2015-01-01

    Quercus pacifica, the island scrub-oak, is the dominant species in oak chaparral on the three largest California Channel Islands. While the population on Santa Cruz Island has experienced a strong recovery, the populations on Santa Rosa and Santa Catalina islands are of conservation concern, and managers are actively restoring oak habitat by...

  13. Asperger's in the Holmes family.

    Science.gov (United States)

    Altschuler, Eric L

    2013-09-01

    I show that Mycroft Holmes (Sherlock Holmes' brother) is a formally described case of Asperger's syndrome a half century before Asperger's description of the syndrome. Further, given the genetic similarity and links between the brothers stated by Sherlock, this also cinches the same diagnosis for Sherlock.

  14. Il segreto di Holmes

    Directory of Open Access Journals (Sweden)

    Silio Bozzi

    2012-11-01

    Full Text Available The most famous of detectives, Sherlock Holmes, is not only a relentless solver of mysteries, but is also an enigma himself. Only another investigator may shed light on the hidden contradictions and mysteries of the universe and perhaps on Holmes’s most secret soul. Nothing short of the merciless analysis of another detective, with his or her scientific training, is able to disassemble and reassemble the theoretic and cognitive machinery of the famous tenant of the 221/b Baker Street and discover that some parts will not fall back into place and that nothing, perhaps, will ever be the same…

  15. [Sherlock Holmes as amateur physician].

    Science.gov (United States)

    Madsen, S

    1998-03-30

    The medical literature contains numerous articles dealing with Sherlock Holmes and his companion Dr. Watson. Some of the articles are concerned with the medical and scientific aspects of his cases. Other articles adopt a more philosophical view: They compare the methods of the master detective with those of the physician--the ideal clinician should be as astute in his profession as the detective must be in his. It this article the author briefly reviews the abilities of Sherlock Holmes as an amateur physician. Often Holmes was brilliant, but sometimes he made serious mistakes. In one of his cases (The Adventure of the Lion's Mane) he misinterpreted common medical signs.

  16. Managing California black oak for tribal ecocultural restoration

    Science.gov (United States)

    Jonathan W. Long; Ron W. Goode; Raymond J. Gutteriez; Jessica J. Lackey; M. Kat Anderson

    2017-01-01

    Many tribes in California and Oregon value California black oak (Quercus kelloggii) as a traditional source of food and other values. Over centuries or millennia, Native Americans learned that they could enhance production of desired resources by regularly igniting low-intensity surface fires in stands of black oak. Although black oak is likely to...

  17. Fire in Eastern North American Oak Ecosystems: Filling the Gaps

    Science.gov (United States)

    Julian (Morgan) Varner; Mary Arthur; Stacy Clark; Daniel C. Dey; Justin Hart; Callie Schweitzer

    2016-01-01

    This special issue of Fire Ecology is focused on the fire ecology of eastern USA oak (Quercus L.) forests, woodlands, and savannas. The papers were presented as part of the Fifth Fire in Eastern Oak Forests Conference in Tuscaloosa, Alabama, USA, in 2015. The topic of fire in eastern oak ecosystems is one that has received insufficient interest from the...

  18. Acorn Production Characteristics of Southern Appalachian Oaks: A Simple Method to Predict Within-Year Crop Size

    Science.gov (United States)

    Cathryn H. Greenberg; Bernard R. Parresol

    2000-01-01

    We examined acorn production from 1993-97 by black oak (Quercus velutina Lam.), northern red oak (Q. rubra L.), scarlet oak (Q. coccinea Muenchh.), chestnut oak (Q. prinus L.), and white oak (Q. alba L.) in the Southern Appalichians to determine how frequency of acorn...

  19. Cork oak woodlands patchiness

    DEFF Research Database (Denmark)

    Costa, Augusta; Madeira, Manuel; Plieninger, Tobias

    2014-01-01

    The cork oak (Quercus suber L.) woodlands of the agroforestry landscapes of Southwestern Iberia are undergoing drastic change due to severe natural and anthropogenic disturbances. These may eventually result in woodland loss or deforestation, the final step of an ongoing process of woodland...... degradation. Monitoring changes in the spatial patterns of woodlands - especially fractional canopy cover of woodlands and/or their patchiness in the landscape mosaic - potentially enables forecasting of loss and responding to it at an early stage. We examine the degradation process in two cork oak woodlands...

  20. An ecologically based approach to oak silviculture: a synthesis of 50 years of oak ecosystem research in North America

    Science.gov (United States)

    Daniel C. Dey; Alejandro A. Royo; Patrick H. Brose; Todd F. Hutchinson; Martin A. Spetich; Scott H. Stoleson

    2010-01-01

    Oak (Quercus L.) is an abundant and widely distributed genus in eastern North America. A history of periodic fire, grazing, canopy disturbance and timber harvesting has favored oak's dominance. But, changes in this regime toward much less fire or complete fire suppression, and selective cutting are causing the successional replacement of oak....

  1. Sherlock Holmes, Master Problem Solver.

    Science.gov (United States)

    Ballew, Hunter

    1994-01-01

    Shows the connections between Sherlock Holmes's investigative methods and mathematical problem solving, including observations, characteristics of the problem solver, importance of data, questioning the obvious, learning from experience, learning from errors, and indirect proof. (MKR)

  2. Sherlock Holmes, Master Problem Solver.

    Science.gov (United States)

    Ballew, Hunter

    1994-01-01

    Shows the connections between Sherlock Holmes's investigative methods and mathematical problem solving, including observations, characteristics of the problem solver, importance of data, questioning the obvious, learning from experience, learning from errors, and indirect proof. (MKR)

  3. SORPTION PERFORMANCE OF QUERCUS CERRIS CORK WITH POLYCYCLIC AROMATIC HYDROCARBONS AND TOXICITY TESTING

    Directory of Open Access Journals (Sweden)

    M. Àngels Olivella

    2011-06-01

    Full Text Available Quercus cerris is an important oak species extended in large areas of Eastern Europe and Minor Asia that has a thick bark which is not utilized at all. The sorption performance of cork from Quercus cerris bark with four polycyclic aromatic hydrocarbons (PAHs (acenaphthene, fluorene, phenanthrene, and anthracene was investigated. Quercus cerris cork was characterized for elemental analysis, acidic groups, and summative chemical composition, and the results were compared with Quercus suber cork. A Microtox® test was carried out to test for the release of any toxic compounds into the solution. All isotherms fit the Freundlich model and displayed linear n values. Quercus cerris exhibited a high efficiency for sorption of PAHs for the studied concentrations (5 to 50 µg/L with 80-96% removal, while the desorption isotherms showed a very low release of the adsorbed PAHs (<2%. In relation to Quercus suber cork, KF values of Quercus cerris cork are about three times lower. The quantity of Quercus cerris cork required to reduce water pollution by PAHs was estimated to be less than twice the quantity of other adsorbents such as aspen wood and leonardite. Toxicity tests indicated that non-toxic compounds were released into the solution by the Quercus cerris and Quercus suber cork samples. Overall the results indicate the potential use of Quercus cerris cork and of Quercus suber cork as effective and economical biosorbents for the treatment of PAH-contaminated waters.

  4. Airborne Quercus pollen in SW Spain: Identifying favourable conditions for atmospheric transport and potential source areas.

    Science.gov (United States)

    Maya-Manzano, José María; Fernández-Rodríguez, Santiago; Smith, Matt; Tormo-Molina, Rafael; Reynolds, Andrew M; Silva-Palacios, Inmaculada; Gonzalo-Garijo, Ángela; Sadyś, Magdalena

    2016-11-15

    The pollen grains of Quercus spp. (oak trees) are allergenic. This study investigates airborne Quercus pollen in SW Spain with the aim identifying favourable conditions for atmospheric transport and potential sources areas. Two types of Quercus distribution maps were produced. Airborne Quercus pollen concentrations were measured at three sites located in the Extremadura region (SW Spain) for 3 consecutive years. The seasonal occurrence of Quercus pollen in the air was investigated, as well as days with pollen concentrations ≥80Pm(-3). The distance that Quercus pollen can be transported in appreciable numbers was calculated using clusters of back trajectories representing the air mass movement above the source areas (oak woodlands), and by using a state-of-the-art dispersion model. The two main potential sources of Quercus airborne pollen captured in SW Spain are Q. ilex subsp. ballota and Q. suber. The minimum distances between aerobiological stations and Quercus woodlands have been estimated as: 40km (Plasencia), 66km (Don Benito), 62km (Zafra) from the context of this study. Daily mean Quercus pollen concentration can exceed 1,700Pm(-3), levels reached not less than 24 days in a single year. High Quercus pollen concentration were mostly associated with moderate wind speed events (6-10ms(-1)), whereas that a high wind speed (16-20ms(-1)) seems to be associated with low concentrations.

  5. Influence of Scale on the Management of Wildlife in California Oak Woodlands

    Science.gov (United States)

    William M. Block; Michael L. Morrison

    1991-01-01

    Distributions, abundances, and patterns of resource use of amphibians, reptiles, birds, and small mammals varied spatially and temporally in California oak woodlands. Spatial variations occurred within stands, between stands of a similar type (e.g., canyon live oak [Quercus chrysolepis], blue oak [Q. douglasii], or valley oak [

  6. Comparison of oak and sugar maple distribution and regeneration in central Illinois upland oak forests

    Science.gov (United States)

    Peter J. Frey; Scott J. Meiners

    2014-01-01

    Changes in disturbance frequencies, habitat fragmentation, and other biotic pressures are allowing sugar maple (Acer saccharum) to displace oak (Quercus spp.) in the upland forest understory. The displacement of oaks by sugar maples represents a major management concern throughout the region. We collected seedling microhabitat data...

  7. Large-scale patterns of Quercus ilex, Quercus suber, and Quercus pyrenaica regeneration in central-western Spain

    DEFF Research Database (Denmark)

    Plieninger, Tobias; Rolo, Víctor; Moreno, Gerardo

    2010-01-01

    categories, from small seedlings to large saplings, and for the three oak species studied, especially the evergreens. Of the Quercus ilex, Q. suber, and Q. pyrenaica plots studied, 49%, 62%, and 20% were lacking any small seedlings, and 82%, 96%, and 56% did not have any large saplings, respectively......In Central-Western Spain, forests and woodlands composed of Quercus sp. support outstanding levels of biodiversity, but there is increasing concern about their long-term persistence due to a lack of regeneration. We hypothesize that this regenerative lack is operating on a large geographic scale...... and Q. suber were positively correlated with all understory variables, suggesting that the presence of pioneer shrubs represent a major safe site for early tree recruitment, independent from specific shrub species. © 2010 Springer Science+Business Media, LLC....

  8. Foliage maturity of Quercus ilex affects the larval development of a Croatian coastal population of Lymantria dispar (Lepidoptera: Erebidae

    Directory of Open Access Journals (Sweden)

    Lukić Ivan

    2017-02-01

    Full Text Available Gypsy moth (Lymantria dispar is one of the most important forest pests in the world. Numerous previous studies focused only on different host tree species, but small number of them on foliage age. Since recent genetic analyses showed that there are significant differences between Croatian continental and coastal population we investigated coastal population since there was no previous research. For this research juvenile and mature foliage of Holm oak (Quercus ilex was used. Larval development was investigated in two laboratory experiments. One experiment involved rearing trials consisting of 50 individual larvae per treatment while a parallel experiment investigated gregarious feeding conditions using 120 larvae in a rearing treatment. Larval mortality was lower and development time shorter for individuals reared on juvenile foliage. High pupation success in both the individual and group rearing experiment for larvae reared on juvenile foliage was also observed. To conclude, our results showed high mortality, poor larval development and low pupation success in larvae reared on mature foliage. This research is significant because in the aspect of ongoing climate changes there is a possibility that gypsy moth will move to the north and shift its distribution by expanding into new climatic area.

  9. Monitoring drought impact on Mediterranean oak savanna vegetation using remote sensing

    Science.gov (United States)

    González-Dugo, Maria P.; Carpintero, Elisabet; Andreu, Ana

    2015-04-01

    A holm oak savanna, known as dehesa in Spain and montado in Portugal, is the largest agroforest ecosystem in Europe, covering about 3 million hectares in the Iberian Peninsula and Greece (Papanastasis et al., 2004). It is considered an example of sustainable land use, supporting a large number of species and diversity of habitats and for its importance in rural development and economy (Plieninger et al., 2001). It is a combination between an agricultural and a naturally vegetated ecosystem, consisting of widely-spaced oak trees (mostly Quercus Ilex and Quercus suber) combined with a sub-canopy composed by crops, annual grassland and/or shrubs. It has a Mediterranean climate with severe periodic droughts. In the last decades, this system is being exposed to multiple threats derived from socio-economic changes and intensive agricultural use, which have caused environmental degradation, including tree decline, changes in soil properties and hydrological processes, and an increase of soil erosion (Coelho et al., 2004). Soil water dynamics plays a central role in the current decline and reduction of forested areas that jeopardizes the preservation of the system. In this work, a series of remotely sensed images since 1990 to present was used to evaluate the effect of several drought events occurred in the study area (1995, 2009, 2010/2011) on the tree density and water status. Data from satellites Landsat and field measurements have been combined in a spectral mixture model to assess separately the evolution of tree, dry grass and bare soil ground coverage. Only summer images have been used to avoid the influence of the green herbaceous layer on the analysis. Thermal data from the same sensors and meteorological information are integrated in a two source surface energy balance model to compute the Evaporative Stress Index (ESI) and evaluate the vegetation water status. The results have provided insights about the severity of each event and the spatial distribution of

  10. Sherlock Holmes as a Social Scientist.

    Science.gov (United States)

    Ward, Veronica; Orbell, John

    1988-01-01

    Presents a way of teaching the scientific method through studying the adventures of Sherlock Holmes. Asserting that Sherlock Holmes used the scientific method to solve cases, the authors construct Holmes' method through excerpts from novels featuring his adventures. Discusses basic assumptions, paradigms, theory building, and testing. (SLM)

  11. Sherlock Holmes as a Social Scientist.

    Science.gov (United States)

    Ward, Veronica; Orbell, John

    1988-01-01

    Presents a way of teaching the scientific method through studying the adventures of Sherlock Holmes. Asserting that Sherlock Holmes used the scientific method to solve cases, the authors construct Holmes' method through excerpts from novels featuring his adventures. Discusses basic assumptions, paradigms, theory building, and testing. (SLM)

  12. I believe in Sherlock Holmes

    DEFF Research Database (Denmark)

    Lauridsen, Palle Schantz

    2012-01-01

    Sherlock Holmes så første gang dagens lys i 1887. I 4 romaner og 56 korte fortællinger berettede Arthur Conan Doyle i en periode på 40 år om de kriminalsager, hans consulting detective løste i samarbejde med sin ven, hjælper og kronikør, Dr. John Watson. Allerede, mens Doyle stadig skrev om Holmes......, vandrede hans figur over i andre medier, og historierne om ham hører i dag til de mest adapterede i verden. Inden for de sidste år er Holmes igen blevet populær både på film og tv. Både BBC’s tv-serie og Guy Ritchies film forholder sig legende til Doyles univers og til Holmes’ seksualitet....

  13. PITYOPHAGUS QUERCUS REITTER, 1877, A NEW SAPROXYLIC SAP BEETLE FOR THE ITALIAN FAUNA (Coleoptera, Nitidulidae

    Directory of Open Access Journals (Sweden)

    Paolo Audisio

    2011-10-01

    Full Text Available During ecological investigations on saproxylic beetle communities of central Italy (Latium, at Bosco Polverino (a mixed evergreen/deciduous forest fragment dominated by cork oaks, and at Allumiere (a small fragment of beech forest surrounded by turkey oak stands, the authors found three specimens of Pityophagus quercus Reitter, 1877 (Coleoptera, Nitidulidae. These are the first known records of this species in Italy, and the first one in association with an evergreen oak, Quercus suber. This discovery led us to review both bionomical and faunistic data so far available on this exceedingly rare and poorly known species.

  14. Sherlock Holmes and intelligent design.

    Science.gov (United States)

    McCuskey, Brian

    2012-09-01

    This article examines how both scientists and creationists, as they argue over intelligent design, invoke and quote the fictional character of Sherlock Holmes to support their opposed positions. Rhetorical analysis ofHolmes's repeated contributions to the debate reveals not only how the argument for design falls apart, but also how the argument for Darwin compromises itself when following the detective onto shaky logical ground. The sciences and the humanities must work together to combat the corrosive influence ofpseudoscientific reasoning on our students and the general public; this article contributes to that joint enterprise.

  15. Acueducto pretensado sobre el Holme

    Directory of Open Access Journals (Sweden)

    Editorial, Equipo

    1958-04-01

    Full Text Available Breve descripción del paso de una canalización de 0,60 m de diámetro, destinada al abastecimiento de aguas, sobre el río Holme (Inglaterra. El puente formado tiene dos vigas de hormigón pretensado, cuyas armaduras se componen de barras McCall.

  16. The Landscapes of Sherlock Holmes.

    Science.gov (United States)

    Tuan, Yi-Fu

    1985-01-01

    By critically reading Conan Doyle's "Sherlock Holmes," geography students can learn about the major beliefs, values, and fears of late Victorian England. The geographical scope of the work is discussed, as well as what the work tells us about beliefs concerning nature, environmental influence, and human nature of the period. (RM)

  17. Jorma Holm : "Sisearhitekti tuleks usaldada"

    Index Scriptorium Estoniae

    2005-01-01

    Eesti sisearhitekt Jorma Holm sellest, mida ta peab oluliseks arhitektuuri ja sisearhitektuuri puhul ning kodude kujundamisel. Jorma Holmist (sünd. 1964), tema olulisemad teostatud tööd. Ill.: J. Holmi portree, 2 kodu vaadet, värv

  18. The Landscapes of Sherlock Holmes.

    Science.gov (United States)

    Tuan, Yi-Fu

    1985-01-01

    By critically reading Conan Doyle's "Sherlock Holmes," geography students can learn about the major beliefs, values, and fears of late Victorian England. The geographical scope of the work is discussed, as well as what the work tells us about beliefs concerning nature, environmental influence, and human nature of the period. (RM)

  19. Field test of foliar-spray herbicides to control mountain laurel in mature mixed-oak forests in western Maryland

    Science.gov (United States)

    Gary W. Miller; Patrick H. Brose; Jeffrey D. Kochenderfer; James N. Kochenderfer; Kurt W. Gottschalk; John R. Denning

    2016-01-01

    Successful oak (Quercus spp.) regeneration requires the presence of competitive sources of oak reproduction before parent oaks are harvested. Mountain laurel (Kalmia latifolia) in the understory of many Appalachian forests prevents new oak seedlings from receiving adequate sunlight to survive and grow into competitive size classes. This study examined the efficacy of...

  20. Long-term energy balance and vegetation water stress monitoring of Mediterranean oak savanna using satellite thermal data

    Science.gov (United States)

    González-Dugo, Maria P.; Chen, Xuelong; Andreu, Ana; Carpintero, Elisabet; Gómez-Giraldez, Pedro; Su, Z.(Bob)

    2017-04-01

    Drought is one of the major hazards faced by natural and cropped vegetation in the Mediterranean Sea Basin. Water scarcity is likely to be worsened under the predicted conditions of climate change, which is expected to make this region both warmer and drier. A Holm oak savanna, known as dehesa in Spain and montado in Portugal, is an agro-silvo-pastoral system occupying more than 3 million hectares the Iberian Peninsula and Greece. It consists of widely-spaced oak trees (mostly Quercus ilex L.), combined with crops, pasture and Mediterranean shrubs. This ecosystem is considered an example of sustainable land use, supporting a large number of species and diversity of habitats and for its importance in rural economy. A similar ecosystem is worldwide distributed in areas with Mediterranean climate (as California or South Africa) and shares structural and functional properties with tropical savannas in Africa, Australia and South America. Remote sensing time series can assist the monitoring of the energy balance components, with special attention to the evapotranspiration and vegetation water stress over these areas. Long-term data analysis may improve our understanding of the functioning of the system, helping to assess drought impacts and leading to reduce the economic and environmental vulnerability of this ecosystem. This work analyzes the evolution the surface energy balance components, mapping the evapotranspiration and moisture stress of holm oak woodlands of Spain and Portugal during the last 15 years (2001-2015). The surface energy balance model (SEBS) has been applied over the Iberian Peninsula on a monthly time scale and 0.05° spatial resolution, using multi-satellite and meteorological forcing data. Modelled energy and water fluxes have been validated using ground measurements of two eddy covariance towers located in oak savanna sites during 3 years, resulting in moderate deviations from observations (10-25 W/m2). The departure of actual ET from the

  1. Effects of drought and shade on growth and water use of Quercus alba, Q. bicolor, Q. imbricaria and Q. palustris seedlings

    Science.gov (United States)

    Joseph J. McCarthy; Jeffrey O. Dawson

    1991-01-01

    Growth and water use efficiency were determined for 2-year-old white oak (Quercus alba), swamp white oak (Q. imbricaria) and pin oak (Q. palustris) seedlings grown under three shade treatments (30, 55 and 73%) and two irrigation regimes (container capacity and mild drought). With species and water regimes...

  2. Effects of fire and browsing on regeneration of blue oak

    Science.gov (United States)

    James W. Bartolome; Mitchel P. McClaran; Barbara H. Allen-Diaz; Jim Dunne; Lawrence D. Ford; Richard B. Standiford; Neil K. McDougald; Larry C. Forero

    2002-01-01

    Blue oaks (Quercus douglasii) are not regenerating well over much of California. The roles of fire and browsing in regeneration are probably significant, but poorly understood. We burned two foothill blue oak woodland sites which contained significant numbers of small trees between 40 and 70 cm tall, then compared height growth over 14 years among 48...

  3. Blue Oak Canopy Effect on Seasonal Forage Production and Quality

    Science.gov (United States)

    William E. Frost; Neil K. McDougald; Montague W. Demment

    1991-01-01

    Forage production and forage quality were measured seasonally beneath the canopy of blue oak (Quercus douglasii) and in open grassland at the San Joaquin Experimental Range. At the March and peak standing crop sampling dates forage production was significantly greater (p=.05) beneath blue oak compared to open grassland. At most sampling dates, the...

  4. Direct Effects of Carpophagous Insects on the Germination Ability and Early Abscission of Oak Acorns

    Directory of Open Access Journals (Sweden)

    CSÓKA, György

    2006-01-01

    Full Text Available Carpophagous insects play an important role in decreasing the viability of acorns in bothdirect and indirect ways. Therefore they significantly influence the reproductive potential of oaks. As adirect effect, their feeding on the embryo and on the cotyledons may prevent the germination of theacorn and on the other hand, their damage causes premature acorn abscission. During 3 years, 60acorn samples from five oak species (Turkey oakQuercus cerris, pedunculate oakQuercus robur,sessile oakQuercus petraea, downy oakQuercus pubescens, red oakQuercus rubra have beeninvestigated. The average rate of damage varied a lot between years, but was always significant (2000:36%, 2001: 61%, 2002: 51%. The insects’ influence causing premature acorn abscission wassignificant both for pedunculate and Turkey oaks. The premature acorn abscission was 34% of thetotal crop in 2000 for pedunculate oak (Curculio spp. 26%, Cydia spp. 2% and Andricusquercuscalicis 6% and 39% in 2001 (Curculio spp. 14%, Cydia spp. 2%, Andricus quercuscalicis13%, Callirhytis glandium 10%. In case of Turkey oak it was 29% in 2001 (C. glandium 16%,Neuroterus saliens 13%, and 12% in 2002 (C. glandium 10%, N. saliens 2%.

  5. Monitoring for pests and diseases in native oak woodlands: the case of acute oak decline in the United Kingdom

    Science.gov (United States)

    Nathan Brown; Stephen Parnell; Frank van den Bosch; Mike Jeger; Sandra Denman

    2017-01-01

    In recent years, a novel form of decline has been observed in southern and central England. This syndrome has been termed acute oak decline (AOD) and affects native oak, Quercus petraea and Q. robur. Typical symptoms include bark cracks that weep dark exudates, which are caused by necrotic patches in the...

  6. Performance of nutrient-loaded red oak and white oak seedlings on mine lands in southern Indiana

    Science.gov (United States)

    K. Francis Salifu; Douglass F. Jacobs; Zonda K. D. Birge

    2008-01-01

    Exponential nutrient loading was used to build nutrient reserves in northern red oak (Quercus rubra) and white oak (Q. alba) seedlings during standard bareroot nursery culture at the Vallonia State Nursery, Indiana. Nursery grown seedlings were outplanted the following year onto a mine reclamation site in southern Indiana to...

  7. Performance of two oak species and three planting stocks on lands damaged by hurricane Katrina

    Science.gov (United States)

    John A. Conrad III; Andrew W. Ezell; Emily B. Schultz; John D. Hodges

    2015-01-01

    Hurricane Katrina had a devastating impact on bottomland hardwood forests in 2005. Artificial regeneration was considered the most appropriate method for reforesting these areas, but few studies have evaluated methods for artificially regenerating oaks on clear cut sites in the southern United States. First-year survival and growth of two oak species, live oak (Quercus...

  8. Biology and Sampling of Red Oak Borer Populations in the Ozark Mountains of Arkansas

    Science.gov (United States)

    Damon Crook; Fred Stephen; Melissa Fierke; Dana Kinney; Vaughn Silisbury

    2004-01-01

    A complex interaction of multiple factors has resulted in >75 percent mortality/decline of more than 1 million acres of red oak (Quercus, subgenus Erythrobalanus) on the Ozark-St. Francis National Forests. The most striking feature of this oak decline event is an unprecedented outbreak of red oak borer. A visual stand assessment...

  9. Comparison of three sampling methods in the characterization of cork oak stands for management purpose

    NARCIS (Netherlands)

    Paulo, M.J.; Tomé, M.; Otten, A.; Stein, A.

    2005-01-01

    The cork oak (Quercus suber L.) is an evergreen oak that has the ability to produce a continuous layer of cork tissue which regenerates after being removed. Cork oak stands can be diverse in structure. Young stands are often regularly spaced, whereas older stands usually show clustering and can be

  10. Comparison of three sampling methods in the characterization of cork oak stands for management purpose

    NARCIS (Netherlands)

    Paulo, M.J.; Tomé, M.; Otten, A.; Stein, A.

    2005-01-01

    The cork oak (Quercus suber L.) is an evergreen oak that has the ability to produce a continuous layer of cork tissue which regenerates after being removed. Cork oak stands can be diverse in structure. Young stands are often regularly spaced, whereas older stands usually show clustering and can be m

  11. Biología reproductiva y conservación: el caso de la regeneración de bosques templados y subtropicales de robles (Quercus spp. Plant reproductive biology and conservation: the case of temperate and subtropical oak forest regeneration

    Directory of Open Access Journals (Sweden)

    Fernando J. Pulido

    2002-03-01

    Full Text Available En este trabajo se revisan los resultados de 21 estudios experimentales sobre la regeneración de bosques de roble (Quercus spp. en los que se analizan al menos tres de las fases del ciclo reproductivo: fertilización, desarrollo de frutos viables, dispersión, consumo postdispersivo, germinación-emergencia de plántulas, establecimiento de juveniles y reclutamiento de adultos. La mayoría de las poblaciones estudiadas se encontraban en bosques templados de Norteamérica y Europa, repartidos de forma equitativa entre bosques de ambientes xéricos (incluidos los mediterráneos con especies perennes y habitualmente bajo explotación, y bosques de ambientes mésicos o montanos con especies generalmente caducifolias y escasamente alterados. Los estudios se clasificaron de acuerdo con los tipos de limitación de la regeneración encontrados por los autores, esto es, producción de semillas viables, presión de herbívoros y disponibilidad de sitios seguros. La revisión muestra que en la mayoría de los casos la regeneración se encontraba limitada por una combinación de factores, típicamente el consumo de bellotas y un ambiente abiótico desfavorable durante el establecimiento. La fecundidad de los árboles ha sido rara vez estudiada a pesar de que puede llegar ser en una limitación frecuente, al igual que ocurre con las limitaciones de la dispersión por animales. Finalmente, se analiza el grado de aplicación de la información ecológica acumulada a la solución de problemas de regeneración natural, y se discute su utilidad en comparación con las prácticas más comunes de regeneración artificial via plantacionesThis study presents a review of 21 experimental studies on oak (Quercus regeneration analysing at least three phases of the reproductive cycle, namely fertilization, viable fruit production, acorn dispersal, postdispersal predation, seedling emergence, sapling establishment, and adult recruitment. Most study cases came from North

  12. Sensitivity analysis of a parameterization of the stomatal component of the DO{sub 3}SE model for Quercus ilex to estimate ozone fluxes

    Energy Technology Data Exchange (ETDEWEB)

    Alonso, Rocio [Ecotoxicology of Air Pollution, CIEMAT, Avenida Complutense 22, 28040 Madrid (Spain)], E-mail: rocio.alonso@ciemat.es; Elvira, Susana [Ecotoxicology of Air Pollution, CIEMAT, Avenida Complutense 22, 28040 Madrid (Spain)], E-mail: susana.elvira@ciemat.es; Sanz, Maria J. [Fundacion CEAM, Charles Darwin 14, 46980 Paterna, Valencia (Spain)], E-mail: mjose@ceam.es; Gerosa, Giacomo [Department of Mathematics and Physics, Universita Cattolica del Sacro Cuore, via Musei 41, 25121 Brescia (Italy)], E-mail: giacomo.gerosa@unicatt.it; Emberson, Lisa D. [Stockholm Environment Institute, University of York, York YO 10 5DD (United Kingdom)], E-mail: lde1@york.ac.uk; Bermejo, Victoria [Ecotoxicology of Air Pollution, CIEMAT, Avenida Complutense 22, 28040 Madrid (Spain)], E-mail: victoria.bermejo@ciemat.es; Gimeno, Benjamin S. [Ecotoxicology of Air Pollution, CIEMAT, Avenida Complutense 22, 28040 Madrid (Spain)], E-mail: benjamin.gimeno@ciemat.es

    2008-10-15

    A sensitivity analysis of a proposed parameterization of the stomatal conductance (g{sub s}) module of the European ozone deposition model (DO{sub 3}SE) for Quercus ilex was performed. The performance of the model was tested against measured g{sub s} in the field at three sites in Spain. The best fit of the model was found for those sites, or during those periods, facing no or mild stress conditions, but a worse performance was found under severe drought or temperature stress, mostly occurring at continental sites. The best performance was obtained when both f{sub phen} and f{sub SWP} were included. A local parameterization accounting for the lower temperatures recorded in winter and the higher water shortage at the continental sites resulted in a better performance of the model. The overall results indicate that two different parameterizations of the model are needed, one for marine-influenced sites and another one for continental sites. - No redundancy between phenological and water-related modifying functions was found when estimating stomatal behavior of Holm oak.

  13. Photosynthetic responses to elevated CO{sub 2} and O{sub 3} in Quercus ilex leaves at a natural CO{sub 2} spring

    Energy Technology Data Exchange (ETDEWEB)

    Paoletti, E. [Istituto Protezione Piante, Consiglio Nazionale delle Ricerche, Via Madonna del Piano 10, I-50019 Sesto Fiorentino, Florence (Italy)]. E-mail: e.paoletti@ipp.cnr.it; Seufert, G. [European Commission, Joint Research Centre, Institute for Environment and Sustainability, I-21020 Ispra (Italy); Della Rocca, G. [Istituto Protezione Piante, Consiglio Nazionale delle Ricerche, Via Madonna del Piano 10, I-50019 Sesto Fiorentino, Florence (Italy); Thomsen, H. [European Commission, Joint Research Centre, Institute for Environment and Sustainability, I-21020 Ispra (Italy)

    2007-06-15

    Photosynthetic stimulation and stomatal conductance (Gs) depression in Quercus ilex leaves at a CO{sub 2} spring suggested no down-regulation. The insensitivity of Gs to a CO{sub 2} increase (from ambient 1500 to 2000 {mu}mol mol{sup -1}) suggested stomatal acclimation. Both responses are likely adaptations to the special environment of CO{sub 2} springs. At the CO{sub 2}-enriched site, not at the control site, photosynthesis decreased 9% in leaves exposed to 2x ambient O{sub 3} concentrations in branch enclosures, compared to controls in charcoal-filtered air. The stomatal density reduction at high CO{sub 2} was one-third lower than the concomitant Gs reduction, so that the O{sub 3} uptake per single stoma was lower than at ambient CO{sub 2}. No significant variation in monoterpene emission was measured. Higher trichome and mesophyll density were recorded at the CO{sub 2}-enriched site, accounting for lower O{sub 3} sensitivity. A long-term exposure to H{sub 2}S, reflected by higher foliar S-content, and CO{sub 2} might depress the antioxidant capacity of leaves close to the vent and increase their O{sub 3} sensitivity. - Very high CO{sub 2} concentrations did not compensate for the effects of O{sub 3} on holm oak photosynthesis.

  14. Acorns containing deeper plumule survive better: how white oaks counter embryo excision by rodents.

    Science.gov (United States)

    Zhang, Mingming; Dong, Zhong; Yi, Xianfeng; Bartlow, Andrew W

    2014-01-01

    Several squirrel species excise the embryo of acorns of most white oak species to arrest germination for long-term storage. However, it is not clear how these acorns counter embryo excision and survive in the arms race of coevolution. In this study, we simulated the embryo excision behavior of squirrels by removing 4 mm of cotyledon from the apical end of white oak acorns differing in embryo depths to investigate the effects of embryo excision on acorn germination and seedling performance of white oak species. The embryo depth in the cotyledons was significantly different among white oak acorns, with Quercus mongolica containing the embryo most deeply in the acorns. We found that artificial embryo excision significantly decreased acorn germination rates of Quercus variabilis, Quercus acutissima, Quercus aliena, Quercus aliena var. acutiserrata, Quercus serrata. var. brevipetiolata but not Q. mongolica. Artificial embryo excision exerted significant negative impacts on seedling performance of all oak species except Quercus aliena. Our study demonstrates the role of embryo depth of acorns in countering embryo excision by squirrels and may explain the fact that squirrels do not perform embryo excision in acorns of Q. mongolica with deeper embryos. This apparent adaptation of acorns sheds light on the coevolutionary dynamics between oaks and their seed predators.

  15. Sovetski Sherlok Holms popal na dengi

    Index Scriptorium Estoniae

    2007-01-01

    Uus-Meremaal lasti välja seeria hõbemünte A. C. Doyle'i loodud kirjanduslikke kujusid Sherlock Holmes'i, dr. Watsonit jt kehastavate vene näitlejatega 1980-ndate aastate nõukogude seriaalist "Sherlock Holmes'i ja doktor Watsoni seiklused"

  16. En glemt kosmopolit. Kunstneren Astrid Holm

    DEFF Research Database (Denmark)

    Abildgaard, Hanne

    2014-01-01

    Discussion of the Danish artist Astrid Holm as part of the Parisian avantgarde before World War I and as leader of the Artists' Croquis School in Copenhagen 1919-1937......Discussion of the Danish artist Astrid Holm as part of the Parisian avantgarde before World War I and as leader of the Artists' Croquis School in Copenhagen 1919-1937...

  17. Sovetski Sherlok Holms popal na dengi

    Index Scriptorium Estoniae

    2007-01-01

    Uus-Meremaal lasti välja seeria hõbemünte A. C. Doyle'i loodud kirjanduslikke kujusid Sherlock Holmes'i, dr. Watsonit jt kehastavate vene näitlejatega 1980-ndate aastate nõukogude seriaalist "Sherlock Holmes'i ja doktor Watsoni seiklused"

  18. Adaptation and film style in "Sherlock Holmes"

    DEFF Research Database (Denmark)

    Lauridsen, Palle Schantz

    2017-01-01

    A film historical and stylistic analysis of Arthur Berthelet's 1916-movie "Sherlock Holmes" which was re-found and restored in 2013.......A film historical and stylistic analysis of Arthur Berthelet's 1916-movie "Sherlock Holmes" which was re-found and restored in 2013....

  19. Sherlock Holmes i litteratur, film og tv

    DEFF Research Database (Denmark)

    Lauridsen, Palle Schantz

    2017-01-01

    Korte præsentationer af centrale Sherlock Holmes-fortællinger til brug for Ordrup Biblioteks litteraturformidling på hjemmesiden......Korte præsentationer af centrale Sherlock Holmes-fortællinger til brug for Ordrup Biblioteks litteraturformidling på hjemmesiden...

  20. Relationship between Insect Infestation and Seed Rain Dynamics of Oriental Cork Oak (Quercus variabilis)%栓皮栎橡子虫蛀特征与种子雨进程的关系

    Institute of Scientific and Technical Information of China (English)

    曹令立; 董钟; 刘文静; 雷晶洁; 申圳; 杨月琴

    2013-01-01

    为了解栓皮栎(Quercus variabilis)种子雨过程及昆虫捕食特征,于2008年和2009年秋季在洛阳天池山次生林中,对栓皮栎种群的种子雨过程和象甲虫的寄生特征进行了调查研究.结果表明,2008年和2009年栓皮栎的种子雨分别发生在8月24日-9月24日、8月22日-9月28日,密度分别为(18.33±10.05)粒/m2、(26.42±14.27)粒/m2,2009年种子雨产量显著大于2008年.2 a的种子雨构成比例有较大差异.2008年,完好种子、败育种子和虫蛀种子的比例分别为24.09%、55.90%和20.01%;2009年,完好种子比例为50.16%,显著高于2008年,败育种子比例为30.28%,显著低于2008年,而虫蛀种子比例为19.56%,2 a间无显著性差异.象甲幼虫寄生率与橡子大小呈显著正相关,说明象甲虫喜欢寄生较大的橡子.%The seed rain dynamics of Quercus variabilis and the characteristics of weevil infestation were investigated in 2008 and 2009 in Luoyang Tianchi mountain forests. Our results showed that the seed rain of Quercus variabilis began from 24 August and ceased on 24 September,with seed density of (18. 33 ± 10. 05) acorn/m2 in 2008. In 2009, the seed rain began from 22 August and ceased on 28 September, with seed density of (26. 42 ± 14. 27) acorn/m2,significantly larger than that in 2008. In addition,large difference was also found in the composition of seed rain in the two years. In 2008, the proportions of sound acorns, aborted acorns and insect-infested acorns were 24. 09%, 55. 90% and 20. 01% , respectively. In 2009, however, the corresponding proportions were 50. 16%,30. 28% and 19. 56% respectively. The proportion of sound acorns in 2009 was significantly higher than that in 2008,while the proportion of aborted acorns in 2009 was significantly lower than that in 2009, but no significant difference was found in the proportion of insect-infested acorns between the two years. A significant positive relationship was found between infestation rate and

  1. Endemic North African Quercus afares Pomel originates from hybridisation between two genetically very distant oak species (Q. suber L. and Q. canariensis Willd.): evidence from nuclear and cytoplasmic markers.

    Science.gov (United States)

    Mir, C; Toumi, L; Jarne, P; Sarda, V; Di Giusto, F; Lumaret, R

    2006-02-01

    Hybridisation is a potent force in plant evolution, although there are few reported examples of stabilised species that have been created through homoploid hybridisation. We focus here on Quercus afares, an endemic North African species that combines morphological, physiological and ecological traits of both Q. suber and Q. canariensis, two phylogenetically distant species. These two species are sympatric with Q. afares over most of its distribution. We studied two Q. afares populations (one from Algeria and one from Tunisia), as well as several populations of both Q. suber and Q. canariensis sampled both within and outside areas where these species overlap with Q. afares. A genetic analysis was conducted using both nuclear (allozymes) and chloroplastic markers, which shows that Q. afares originates from a Q. suber x Q. canariensis hybridisation. At most loci, Q. afares predominantly possesses alleles from Q. suber, suggesting that the initial cross between Q. suber and Q. canariensis was followed by backcrossing with Q. suber. Other hypotheses that can account for this result, including genetic drift, gene silencing, gene conversion and selection, are discussed. A single Q. suber chlorotype was detected, and all Q. afares individuals displayed this chlorotype, indicating that Q. suber was the maternal parent. Q. afares is genetically, morphologically and ecologically differentiated from its parental species, and can therefore be considered as a stabilised hybrid species.

  2. 栎空腔瘿蜂虫瘿在栓皮栎上的空间分布%Spatial distribution of gall wasp Trichagalma glabrosa on cork oak Quercus variabilis

    Institute of Scientific and Technical Information of China (English)

    王景顺; 张坤朋; 王相宏; 武三安

    2016-01-01

    应用生物统计方法对栎空腔瘿蜂(Trichagalma glabrosa)有性世代和无性世代虫瘿在栓皮栎(Quercus varia-bilis)空间分布特性进行了调查分析.结果表明,栎空腔瘿蜂有性世代和无性世代虫瘿均成聚集分布,聚集的原因是由栎空腔瘿蜂本身的生物学特性或生物学特性与环境的异质性共同作用所决定.水平方位上,虫瘿密度差异不显著,垂直方位上,有性世代虫瘿密度在栓皮栎树冠的下层最高,无性世代虫瘘密度在树冠的上层最高.

  3. Flower Bud Differentiation in Quercus suber L.

    Directory of Open Access Journals (Sweden)

    Maria Carolina Varela

    2016-06-01

    Full Text Available Background and Purpose: Cork oak (Quercus suber L. is one of the most important forest species growing in the Western Mediterranean region. This investigation intends to assess the timing of flowering differentiation of cork oak and contribute to the deepening of the knowledge about the process of the sexual reproduction of the species. Materials and Methods: In 2010 four trees were selected (9, 14, 24, 25 from a plot of 25 trees located at Quinta da Serra, Portugal. A total of 240 buds were collected from these four trees, on three days (8, 14 and 23 March, from 4 branches per tree and 5 positions per branch for the assessment of meristem differentiation. Results: Meristem differentiation analysed on the sampling days revealed there were only vegetative structures by 8 March; a few male and female primordia on 14 March; and fully differentiated reproductive structures on 23 March. Conclusions: Flowering sex determination of cork oak occurs about one month before the flowering onset.

  4. Three new species of Collembola from soils of Mediterranean cork-oak forests of Sicily (Italy).

    Science.gov (United States)

    Giuga, Luca; Jordana, Rafael

    2013-01-01

    Three new species of soil Collembola from cork-oak (Quercus suber) forests located in eastern Sicily (Italy) are described Neonaphorura alicatai sp. nov., Friesea guarinoi sp. nov. and Arrhopalites antonioi sp. nov..

  5. HIDROFOBICIDAD EN ANDISOLES BAJO ROBLEDAL (Quercus humboldtii Y PLANTACIONES FORESTALES (Pinus patula y Cupressus lusitanica EN LA CUENCA DE LA QUEBRADA PIEDRAS BLANCAS (MEDELLÍN, COLOMBIA HYDROPHOBICITY OF ANDISOLS OF OAK GROVES (Quercus humboldtii AND TREE PLANTATIONS (Pinus patula and Cupressus lusitanica IN THE PIEDRAS BLANCAS WATERSHED ( MEDELLÍN, COLOMBIA

    Directory of Open Access Journals (Sweden)

    Juan Raúl Duque Zapata

    2004-12-01

    Full Text Available En la cuenca de la quebrada Piedras Blancas se evaluó la persistencia de la repelencia al agua en el horizonte A de Andisoles bajo tres coberturas vegetales: Pinus patula, Cupressus lusitanica y Quercus humboldtii y en tres posiciones topográficas diferentes a lo largo de la vertiente de colinas bajas, mediante el método de WDPT, en muestras con la humedad de campo y secas al aire. En todas las coberturas se encontró repelencia al agua en los suelos. Además, cuando las muestras fueron secadas al aire, la persistencia de la repelencia al agua se incrementó. Se encontró diferencia significativa en la distribución de la persistencia de la repelencia al agua entre las coberturas y entre las posiciones en la vertiente de las colinas, sin que se presentara un comportamiento similar para las tres coberturas. Los suelos bajo cobertura de ciprés fueron los que presentaron los mayores valores de WDPT en todas las condiciones de medida, siendo este el primer reporte que se hace en la literatura, con un amplio respaldo muestral, de repelencia al agua en suelos bajo dicha cobertura vegetal. En ninguno de los casos, la humedad de las muestras fue el parámetro que explicara el comportamiento observado en la repelencia al agua de los suelos estudiados.The persistence of water repellency in the A horizon of Andisols was evaluated in the Piedras Blancas watershed under three vegetative covers: Pinus patula, Cupressus lusitanica, and Quercus humboldtii, and in three different topographic conditions across the slope of a low hill, using the WDPT method with samples containing field humidities and airdried samples. In all vegetative covers, water repellency of the soils was documented. Also, when the samples were air-dried, the persistency of the water repellency increased. A significant difference in the distribution of water repellency was documented among the different vegetative covers and topographic conditions, without a consistent pattern for the

  6. Mycorrhizas on nursery and field seedlings of Quercus garryana.

    Science.gov (United States)

    Southworth, Darlene; Carrington, Elizabeth M; Frank, Jonathan L; Gould, Peter; Harrington, Connie A; Devine, Warren D

    2009-03-01

    Oak woodland regeneration and restoration requires that seedlings develop mycorrhizas, yet the need for this mutualistic association is often overlooked. In this study, we asked whether Quercus garryana seedlings in nursery beds acquire mycorrhizas without artificial inoculation or access to a mycorrhizal network of other ectomycorrhizal hosts. We also assessed the relationship between mycorrhizal infection and seedling growth in a nursery. Further, we compared the mycorrhizal assemblage of oak nursery seedlings to that of conifer seedlings in the nursery and to that of oak seedlings in nearby oak woodlands. Seedlings were excavated and the roots washed and examined microscopically. Mycorrhizas were identified by DNA sequences of the internal transcribed spacer region and by morphotype. On oak nursery seedlings, predominant mycorrhizas were species of Laccaria and Tuber with single occurrences of Entoloma and Peziza. In adjacent beds, seedlings of Pseudotsuga menziesii were mycorrhizal with Hysterangium and a different species of Laccaria; seedlings of Pinus monticola were mycorrhizal with Geneabea, Tarzetta, and Thelephora. Height of Q. garryana seedlings correlated with root biomass and mycorrhizal abundance. Total mycorrhizal abundance and abundance of Laccaria mycorrhizas significantly predicted seedling height in the nursery. Native oak seedlings from nearby Q. garryana woodlands were mycorrhizal with 13 fungal symbionts, none of which occurred on the nursery seedlings. These results demonstrate the value of mycorrhizas to the growth of oak seedlings. Although seedlings in nursery beds developed mycorrhizas without intentional inoculation, their mycorrhizas differed from and were less species rich than those on native seedlings.

  7. Use of damage surveys and field inventories to evaluate oak and sugar maple health in the northern United States

    Science.gov (United States)

    Randall S Morin; Christopher W. Woodall; Jim Steinman; Charles H. Perry

    2009-01-01

    Oak species (Quercus spp.) and sugar maple (Acer saccharum) are substantial components of the forest ecosystems in the 24-state region spanning the northern U.S. During recent decades, both damage surveys and forest inventories have documented declines of sugar maple and oak health. In order to more fully assess the status of oak and sugar maple health, we examined...

  8. Verification of a useful character for separating the sexes of the goldspotted oak borer, Agrilus coxalis auroguttatus (Coleoptera: Buprestidae)

    Science.gov (United States)

    T.W. Coleman; S.J. Seybold

    2010-01-01

    The goldspotted oak borer, Agrilus coxalis auroguttatus Schaeffer (Coleoptera: Buprestidae), is a new threat to several native oak species in California (CA) (Coleman & Seybold 2008a, b). The beetle larvae feed in and damage the outer xylem, cambium, and phloem of coast live oak, Quercus agrifolia Née (Fagaceae),...

  9. Mercury Distribution and Seasonal and Inter annual Variation of Mercury in Oak (Quercus ilex L.) in Almadenejos (Ciudad Real, Spain); Distribucion y Variacion Estacional e Interanual de Mercurio en La Encina (Quercus ilex L.) en el Municipio de Almadenejos (Ciudad Real)

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-Alonso, J.; Sierra, M. J.; Millan, R.

    2014-10-01

    Plants that are exposed to environmental pollutants are able to accumulate them in their organs depending on plant species, type of organ or age among others. Evergreen plants can hold stems and leaves of the different age over the same branch. Thus, the amount of contaminants of these former organs could vary with its age because the contamination exposure time is different. The aim of this study is to know in a tree species, the mercury (Hg) distribution in it and the variation of Hg concentration in leaves and stems between consecutive years and along the same year. In order to carry this objective out, three different trees of Quercus ilex L. were selected and two branches were taken from each of them. Such trees are located in Almadenejos, a village from the Almaden mining district (Ciudad Real, Spain), an area well known due to the developed Hg mining activities for centuries. Considering each branch and each year, on average the results show that leaves had higher Hg concentration than stems. Furthermore, the lowest Hg concentration was measured in fruit (acorn). With regard to ageing effect on Hg concentration and taking into account each branch separately, the results show that the older leaves had higher Hg concentration than younger ones. Nevertheless, the oldest stems had not always higher Hg concentration than youngest ones. A seasonal variation in Hg content appeared both in leaves and in stems in 2010, increasing in 6.2 times on average, in about six months. This result suggests that this kind of organs should be analyzed in winter months. Finally, the results show a very high positive correlation between the Hg of the bark and the Hg of the wood in the sampled branches. Such result suggests that if bark is sampled and its Hg content is analyzed, we could know the Hg content in the big branches or in the trunk, avoiding the cutting of the branches or the whole tree. (Author)

  10. Embryogenesis in Oak species. A review

    Directory of Open Access Journals (Sweden)

    Aranzazu Gomez-Garay

    2014-08-01

    Full Text Available Aim of study: A review on the propagation methods of four Quercus species, namely Q. suber, Q. robur, Q. ilex and Q. canariensis, through somatic embryogenesis and anther embryogenesis are presented.Area of study: The study comprises both Mediterranean and Atlantic oak species located in Spain.Material and Methods: Somatic embryogenesis was induced on immature zygotic embryos of diverse oak species, permitting the multiplication of half-sib families. Induction of haploid embryos and doubled haploids was assayed in both Q. suber and Q. ilex by temperature stress treatments of anthers containing late vacuolated microspores. The haploid origin of the anther embryos has been evaluated by quantitative nuclear DNA analysis through flow cytometry and by DNA microsatellite markers. Genetic transformation of cork oak has also been performed by means of Agrobacterium tumefaciens vectors. Proteomic analysis has been conducted to screen the diverse protein profiles followed by in vitro derived embryos during their development.Research highlights: Successful plant regeneration from both somatic and haploid embryos has been achieved. In the particular case of cork oak, doubled-haploid plants were obtained. Plantlets regenerated from selected parent trees through somatic embryogenesis were acclimated in the greenhouse and in the nursery, and were planted in an experimental plot in the field. Preliminary evaluation of the cork quality of the plants showed a good heritability correlation with the parent trees. This article revises the work of and is dedicated to Dr. M.A. Bueno, who devoted much of her professional life to the research on Biotechnology and Genetics of forest species, leading the Laboratory of Forest Biotechnology at the Spanish Institute of Agronomic Research (INIA.Key words: anther embryogenesis; microspore; pollen; Quercus canariensis; Quercus ilex; Quercus robur; Quercus suber; somatic embryogenesis. 

  11. Sherlock Holmes and the Educational Process.

    Science.gov (United States)

    Kellog, Richard L.

    1980-01-01

    Examines significant factors in the teaching-learning process which appear in Arthur Conan Doyle's fiction about Sherlock Holmes. These processes include deduction, memory, specialized knowledge, perception, emotional control, and divergent thinking. (Author/KC)

  12. Bioassessment of Black Creek, Holmes County, Mississippi

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Physical, chemical and biological components at four stations on Black Creek and one station on Harland Creek (reference site), Holmes County, Mississippi were...

  13. Sherlock Holmes and the Educational Process.

    Science.gov (United States)

    Kellog, Richard L.

    1980-01-01

    Examines significant factors in the teaching-learning process which appear in Arthur Conan Doyle's fiction about Sherlock Holmes. These processes include deduction, memory, specialized knowledge, perception, emotional control, and divergent thinking. (Author/KC)

  14. Holmes' tremor caused by midbrain cavernoma

    Institute of Scientific and Technical Information of China (English)

    ZHONG Jun; LI Shi-ting; XU Shun-qing; WAN Liang

    2007-01-01

    @@ Holmes' tremor has been postulated as a syndrome attributed to those lesions that interrupt the dentatethalamic and the nigrostriatal tracts thus causing both an action and a rest tremor.1 It may arise from various underlying structural disorders including multiple sclerosis, stroke, or tumors. So far, to our knowledge, few studies on Holmes' tremor secondary to cavernoma have been reported.2 Here we report a case of disabling tremor,who harbored a cavernoma in the midbrain.

  15. Sherlock Holmes and the Nebulous Nitro

    Science.gov (United States)

    Waddell, Thomas G.; Rybolt, Thomas R.

    1996-12-01

    The following story describes a chemical mystery with an emphasis on knowledge in basic organic chemistry, scientific observation, and reasoning skills. This is the eighth article in a series presenting a scientific problem in mystery form in the context of the popular and beloved characters Sherlock Holmes and Dr. Watson (1 - 7). There is a break in the story where the reader (students and teachers) can ponder and solve the mystery. Sherlock Holmes provides his solution in the paragraphs following this break.

  16. Gamle og nye Holmes-fans

    DEFF Research Database (Denmark)

    Lauridsen, Palle Schantz

    2016-01-01

    På baggrund af et internetbaseret spørgeskema undersøger artiklen forskelle og ligheder mellem medlemmer af Sherlock Holmes Klubben i Danmark og følgere af facebook-siden Sherlocked.dk......På baggrund af et internetbaseret spørgeskema undersøger artiklen forskelle og ligheder mellem medlemmer af Sherlock Holmes Klubben i Danmark og følgere af facebook-siden Sherlocked.dk...

  17. y Quercus laurina

    Directory of Open Access Journals (Sweden)

    R. Flores-Velázquez

    2007-01-01

    Full Text Available Se determinaron las características de maquinado con base en la norma ASTM D 1666-87, en las operaciones de cepillado, barrenado, moldurado, torneado y lijado de la madera de Quercus affinis y Quercus laurina. Los mejores resultados de cepillado para Q. affinis se encontraron al combinar el ángulo de corte de 15º y una velocidad de alimentación de 7.5 m·min-1, para Q. laurina no hubo influencia del ángulo de corte. En el barrenado se obtuvieron excelentes resultados con las dos velocidades de giro de broca probadas. Para el moldurado, los resultados para las dos especies fueron excelentes en ambos cortes. En el torneado se encontró que no existe influencia del contenido de humedad para Q. laurina, mientras que para Q. affinis se clasificó como buena para un contenido de humedad menor y excelente para el mayor contenido de humedad. Y para el lijado los resultados fueron excelentes. De acuerdo a los resultados de las pruebas, las dos especies son apropiadas para ser utilizadas por la industria maderera para la elaboración de productos terminados de alta calidad.

  18. Landscape dynamics in Mediterranean oak forests under global change: understanding the role of anthropogenic and environmental drivers across forest types.

    Science.gov (United States)

    Acácio, Vanda; Dias, Filipe S; Catry, Filipe X; Rocha, Marta; Moreira, Francisco

    2017-03-01

    The Mediterranean region is projected to be extremely vulnerable to global change, which will affect the distribution of typical forest types such as native oak forests. However, our understanding of Mediterranean oak forest responses to future conditions is still very limited by the lack of knowledge on oak forest dynamics and species-specific responses to multiple drivers. We compared the long-term (1966-2006) forest persistence and land cover change among evergreen (cork oak and holm oak) and deciduous oak forests and evaluated the importance of anthropogenic and environmental drivers on observed changes for Portugal. We used National Forest Inventories to quantify the changes in oak forests and explored the drivers of change using multinomial logistic regression analysis and an information theoretical approach. We found distinct trends among oak forest types, reflecting the differences in oak economic value, protection status and management schemes: cork oak forests were the most persistent (62%), changing mostly to pines and eucalypt; holm oak forests were less persistent (53.2%), changing mostly to agriculture; and deciduous oak forests were the least persistent (45.7%), changing mostly to shrublands. Drivers of change had distinct importance across oak forest types, but drivers from anthropogenic origin (wildfires, population density, and land accessibility) were always among the most important. Climatic extremes were also important predictors of oak forest changes, namely extreme temperatures for evergreen oak forests and deficit of precipitation for deciduous oak forests. Our results indicate that under increasing human pressure and forecasted climate change, evergreen oak forests will continue declining and deciduous oak forests will be replaced by forests dominated by more xeric species. In the long run, multiple disturbances may change competitive dominance from oak forests to pyrophytic shrublands. A better understanding of forest dynamics and the

  19. Modeling the effectiveness of tree planting to mitigate habitat loss in blue oak woodlands

    Science.gov (United States)

    Richard B. Standiford; Douglas McCreary; William Frost

    2002-01-01

    Many local conservation policies have attempted to mitigate the loss of oak woodland habitat resulting from conversion to urban or intensive agricultural land uses through tree planting. This paper models the development of blue oak (Quercus douglasii) stand structure attributes over 50 years after planting. The model uses a single tree, distance...

  20. The temporal distribution and carbon storage of large oak wood in streams and floodplain deposits

    Science.gov (United States)

    Richard P. Guyette; Daniel C. Dey; Michael C. Stambaugh

    2008-01-01

    We used tree-ring dating and 14C dating to document the temporal distribution and carbon storage of oak (Quercus spp.) wood in trees recruited and buried by streams and floodplains in northern Missouri, USA. Frequency distributions indicated that oak wood has been accumulating in Midwest streams continually since at least the...

  1. Influence of flooding, freezing, and American beaver herbivory on survival of planted oak seedlings

    Science.gov (United States)

    Johnathan T. Reeves; Andrew W. Ezell; John D. Hodges; Emily B. Schultz; Andrew B. Self

    2016-01-01

    Good seedlings, proper planting, and competition control normally result in successful hardwood planting. However, other factors can have serious impact on planting success, such as the impact of flooding, freezing, and the American beaver (Castor canadensis). In 2014, three planting stocks of Nuttall oak (Quercus nuttallii) and Shumard oak (

  2. A stand-development approach to oak afforestation in the lower Mississippi alluvial valley

    Science.gov (United States)

    Brian Roy Lockhart; Emile Gardiner; Theodor Leininger; John Stanturf

    2008-01-01

    Oak (Quercus spp.) afforestation in the Lower Mississippi Alluvial Valley has involved planting 1-year-old bareroot seedlings on a relatively wide spacing in single-species stands or planting light-seeded species with oaks to form mixed-species stands. In the former case, the developing single-species stands have limited future management options...

  3. Effects of wildfire on blue oak in the northern Sacramento Valley

    Science.gov (United States)

    Marc Horney; Richard B. Standiford; Douglas McCreary; Jerry Tecklin; Roy Richards

    2002-01-01

    The objective of this project was to develop a technique for rapidly determining the extent of wildfire damage to blue oaks (Quercus douglasii) that would be usable by landowners without requiring extensive training. In late winter 2000, 100 oaks of various sizes and degrees of damage were selected from 10 plots located where wildfires had burned in...

  4. The state of the system and steps toward resilience of distrubance-dependent oak forests

    Science.gov (United States)

    Tricia G. Knoot; Lisa A. Schulte; John C. Tyndall; Brian J. Palik

    2010-01-01

    Current ecological, economic, and social conditions present unique challenges to natural resource managers seeking to maintain the resilience of disturbance-dependent ecosystems, such as oak (Quercus spp.) forests. Oak-dominated ecosystems throughout the U.S. have historically been perpetuated through periodic disturbance, such as fire, but more...

  5. A spatial statistical analysis of cork oak competition in two Portuguese silvopastoral systems

    NARCIS (Netherlands)

    Paulo, M.J.; Stein, A.; Tomé, M.

    2002-01-01

    This paper considers competition among cork oaks (Quercus suber L.) at three plots in two representative Portuguese stands. It uses spatial point pattern functions to describe densities and quantify differences among stands. Relations between cork oak characteristics and indices measuring intertree

  6. Anthropogenic fire history and red oak forests in south-central Ontario

    Science.gov (United States)

    Daniel C. Dey; Richard P. Guyette

    2000-01-01

    The regeneration and dominance of northern red oak (Quercus rubra L.) has been associated with fire throughout eastern North America. Red oak in central Ontario grows near the northern edge of its distribution in mixed hardwood - coniferous forests under mesic conditions where it competes with more shade-tolerant species. We hypothesized that the...

  7. Sherlock Holmes's Methods of Deductive Reasoning Applied to Medical Diagnostics

    OpenAIRE

    1985-01-01

    Having patterned the character of Sherlock Holmes after one of his professors, Sir Arthur Conan Doyle, himself a physician, incorporated many of the didactic qualities of the 19th century medical diagnostician into the character of Holmes. In this paper I explore Holmes's techniques of deductive reasoning and their basis in 19th and 20th century medical diagnostics.

  8. Holmes for Historians: Sherlock and the Elusive Quest.

    Science.gov (United States)

    Vacha, J. E.

    1988-01-01

    Examines the Sherlock Holmes stories of Sir Arthur Conan Doyle to see what interest and value the fictional detective may hold for historians. Reviewing several of the detective's adventures, the author states that both Holmes and historians are searching for a usable past and that, as explained by Holmes, historical method need not be a complex,…

  9. Sherlock Holmes's Methods of Deductive Reasoning Applied to Medical Diagnostics

    Science.gov (United States)

    Miller, Larry

    1985-01-01

    Having patterned the character of Sherlock Holmes after one of his professors, Sir Arthur Conan Doyle, himself a physician, incorporated many of the didactic qualities of the 19th century medical diagnostician into the character of Holmes. In this paper I explore Holmes's techniques of deductive reasoning and their basis in 19th and 20th century medical diagnostics. PMID:3887762

  10. Holmes for Historians: Sherlock and the Elusive Quest.

    Science.gov (United States)

    Vacha, J. E.

    1988-01-01

    Examines the Sherlock Holmes stories of Sir Arthur Conan Doyle to see what interest and value the fictional detective may hold for historians. Reviewing several of the detective's adventures, the author states that both Holmes and historians are searching for a usable past and that, as explained by Holmes, historical method need not be a complex,…

  11. Sherlock Holmes' methods of deductive reasoning applied to medical diagnostics.

    Science.gov (United States)

    Miller, L

    1985-03-01

    Having patterned the character of Sherlock Holmes after one of his professors, Sir Arthur Conan Doyle, himself a physician, incorporated many of the didactic qualities of the 19th century medical diagnostician into the character of Holmes. In this paper I explore Holmes's techniques of deductive reasoning and their basis in 19th and 20th century medical diagnostics.

  12. The Sherlock Holmes method in clinical practice.

    Science.gov (United States)

    Sopeña, B

    2014-04-01

    This article lists the integral elements of the Sherlock Holmes method, which is based on the intelligent collection of information through detailed observation, careful listening and thorough examination. The information thus obtained is analyzed to develop the main and alternative hypotheses, which are shaped during the deductive process until the key leading to the solution is revealed. The Holmes investigative method applied to clinical practice highlights the advisability of having physicians reason through and seek out the causes of the disease with the data obtained from acute observation, a detailed review of the medical history and careful physical examination.

  13. Observation, Sherlock Holmes, and Evidence Based Medicine.

    Science.gov (United States)

    Osborn, John

    2002-01-01

    Sir Arthur Conan Doyle, the creator of the fictional detective Sherlock Holmes, studied medicine at the University of Edinburgh between 1876 and 1881 under Doctor Joseph Bell who emphasised in his teaching the importance of observation, deduction and evidence. Sherlock Holmes was modelled on Joseph Bell. The modern notions of Evidence Based Medicine (EBM) are not new. A very brief indication of some of the history of EBM is presented including a discussion of the important and usually overlooked contribution of statisticians to the Popperian philosophy of EBM.

  14. Interannual consistency of gross energy in red oak acorns

    Science.gov (United States)

    A.G. Leach; R.M. Kaminski; J.N. Straub; A.W. Ezell; T.S. Hawkins; T.D. Leininger

    2013-01-01

    Red oak Quercus spp., Subgenus Erythrobalanus acorns are forage for mallards Anas platyrhyncos, wood ducks Aix sponsa, and other wildlife that use bottomland hardwood forests in the southeastern United States. However, annual variation in true metabolizable energy from acorns would affect carrying-capacity estimates of bottomland hardwood forests for wintering ducks....

  15. Assessing the risk caused by ground level ozone to European forest trees: A case study in pine, beech and oak across different climate regions

    Energy Technology Data Exchange (ETDEWEB)

    Emberson, Lisa D. [Stockholm Environment Institute, University of York, York YO10 5DD (United Kingdom)]. E-mail: l.emberson@york.ac.uk; Bueker, Patrick [Stockholm Environment Institute, University of York, York YO10 5DD (United Kingdom); Ashmore, Mike R. [Stockholm Environment Institute, University of York, York YO10 5DD (United Kingdom)

    2007-06-15

    Two different indices have been proposed for estimation of the risk caused to forest trees across Europe by ground-level ozone, (i) the concentration based AOT40 index (Accumulated Over a Threshold of 40 ppb) and (ii) the recently developed flux based AFstY index (Accumulated stomatal Flux above a flux threshold Y). This paper compares the AOT40 and AFstY indices for three forest trees species at different locations in Europe. The AFstY index is estimated using the DO{sub 3}SE (Deposition of Ozone and Stomatal Exchange) model parameterized for Scots pine (Pinus sylvestris), beech (Fagus sylvatica) and holm oak (Quercus ilex). The results show a large difference in the perceived O{sub 3} risk when using AOT40 and AFstY indices both between species and regions. The AOT40 index shows a strong north-south gradient across Europe, whereas there is little difference between regions in the modelled values of AFstY. There are significant differences in modelled AFstY between species, which are predominantly determined by differences in the timing and length of the growing season, the periods during which soil moisture deficit limits stomatal conductance, and adaptation to soil moisture stress. This emphasizes the importance of defining species-specific flux response variables to obtain a more accurate quantification of O{sub 3} risk. - A new flux-based model provides a revised assessment of risks of ozone impacts to European forests.

  16. Assessing the risk caused by ground level ozone to European forest trees: a case study in pine, beech and oak across different climate regions.

    Science.gov (United States)

    Emberson, Lisa D; Büker, Patrick; Ashmore, Mike R

    2007-06-01

    Two different indices have been proposed for estimation of the risk caused to forest trees across Europe by ground-level ozone, (i) the concentration based AOT40 index (Accumulated Over a Threshold of 40 ppb) and (ii) the recently developed flux based AFstY index (Accumulated stomatal Flux above a flux threshold Y). This paper compares the AOT40 and AFstY indices for three forest trees species at different locations in Europe. The AFstY index is estimated using the DO(3)SE (Deposition of Ozone and Stomatal Exchange) model parameterized for Scots pine (Pinus sylvestris), beech (Fagus sylvatica) and holm oak (Quercus ilex). The results show a large difference in the perceived O(3) risk when using AOT40 and AFstY indices both between species and regions. The AOT40 index shows a strong north-south gradient across Europe, whereas there is little difference between regions in the modelled values of AFstY. There are significant differences in modelled AFstY between species, which are predominantly determined by differences in the timing and length of the growing season, the periods during which soil moisture deficit limits stomatal conductance, and adaptation to soil moisture stress. This emphasizes the importance of defining species-specific flux response variables to obtain a more accurate quantification of O(3) risk.

  17. Autonomous Duffing-Holmes Type Chaotic Oscillator

    DEFF Research Database (Denmark)

    Tamaševičius, A.; Bumelienė, S.; Kirvaitis, R.

    2009-01-01

    We have designed and built a novel Duffing type autonomous 3rd-order chaotic oscillator. In comparison with the common non-autonomous DuffingHolmes type oscillator the autonomous circuit has an internal positive feedback loop instead of an external periodic drive source. In addition...

  18. Mr. Sherlock Holmes: Teaching Exemplar Extraordinary.

    Science.gov (United States)

    Abrell, Ron

    1979-01-01

    Literature offers an unusually rich store of fictional characters from which all educators can learn much. Sherlock Holmes constitutes a model whose personal characteristics, love of truth, concern for his fellow man, and teaching ability exemplify the best in pedagogy. (Author)

  19. Mr. Sherlock Holmes: Teaching Exemplar Extraordinary.

    Science.gov (United States)

    Abrell, Ron

    1979-01-01

    Literature offers an unusually rich store of fictional characters from which all educators can learn much. Sherlock Holmes constitutes a model whose personal characteristics, love of truth, concern for his fellow man, and teaching ability exemplify the best in pedagogy. (Author)

  20. Tree-ring growth and wood chemistry response to manipulated precipitation variation for two temperate Quercus species

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, Rebekah J. [Pennsylvania State University, University Park, PA; Kaye, Margot W. [Pennsylvania State University, University Park, PA; Abrams, Marc D. [Pennsylvania State University, University Park, PA; Hanson, Paul J [ORNL; Martin, Madhavi Z [ORNL

    2012-01-01

    We examined the relationship among ambient and manipulated precipitation, wood chemistry, and their relationship with radial growth for two oak species in eastern Tennessee. The study took place on the Walker Branch Throughfall Displacement Experiment (TDE) site, located at the Oak Ridge National Laboratory in Oak Ridge, TN. Two dominant species, white oak (Quercus alba) and chestnut oak (Quercus prinus), were selected for study from a 13-year experiment of whole-stand precipitation manipulation (wet, ambient and dry). The relationships between tree-ring width and climate were compared for both species to determine the impact of precipitation manipulations on ring width index. This study used experimental spectroscopy techniques to measure the sensitivity of tree-ring responses to directional changes in precipitation over 13 years, and the results suggest that oaks at this study site are resilient to imposed changes, but sensitive to inter-annual variations in climate. Laser-induced breakdown spectroscopy (LIBS) allowed us to measure nutrient intensities (similar to element concentrations) at 0.5-1.0 mm spacing along the radial growth axis of trees growing in the wet, ambient, and dry treatment sites. A difference in stemwood nutrient levels was observed between the two oak species and among the three treatments. Significant variation in element intensity was observed across treatments for some elements (Ca, K, Mg, Na, N and P) suggesting the potential for long-term impacts on growth under a changing climate regimes for southeastern oaks.

  1. Penicillium cecidicola, a new species on cynipid insect galls on Quercus pacifica in the western United States

    DEFF Research Database (Denmark)

    Seifert, K.A.; Hoekstra, E.H.; Frisvad, Jens Christian

    2004-01-01

    A synnematous species of Penicillium subgenus Biverticillium was found inside emergence tunnels from insect galls (Cynipidae, Hymenoptera, the so-called gall wasps) on scrub oaks (Quercus pacifica Nixon & C.H. Muller) collected in the western United States. The fungus produces synnemata with white...

  2. Root desiccation and drought stress responses of bareroot Quercus rubra seedlings treated with a hydrophilic polymer root dip

    Science.gov (United States)

    Kent G. Apostol; Douglass F. Jacobs; R. Kasten Dumroese

    2009-01-01

    Root hydrogel, a hydrophilic polymer, has been used to improve transplanting success of bareroot conifer seedlings through effects on water holding capacity. We examined mechanisms by which Terra-sorb Fine Hydrogel reduces damage that occurs when roots of 1-year old, dormant northern red oak (Quercus rubra L.) were subjected to shortterm (1, 3, and 5...

  3. Effects of leaf area of downy oak (Quercus pubescens Willd ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-08-18

    Aug 18, 2009 ... gravity meter with sensitivity of 0.01 g and by means of formula 1. The 1st and 2nd age ... multiplying these values the area of a leaf (l.a, mm2) is calculated. 4. ..... Considering obtained data from this study of effects of leaf area ...

  4. Molecular diversity among Turkish oaks (QUERCUS) using random ...

    African Journals Online (AJOL)

    aykut

    2013-11-06

    Nov 6, 2013 ... 1Department of Molecular Biology and Genetics, Faculty of Science and Arts, Uşak University, 64200 Uşak, Turkey. 2Department ... sing and wind-pollination species. ... merase chain reaction (PCR) based technique used to.

  5. Contrasting the effects of organic matter removal and soil compaction on root biomass of 9-year-old red oak, white oak, and shortleaf pine in a Missouri Ozark forest

    Science.gov (United States)

    Felix Jr. Ponder

    2011-01-01

    Nine-year old artificially regenerated red oak (Quercus rubra L.), white oak (Q. alba L.), and shortleaf pine (Pinus echinata Mill.) trees were excavated from plot borders of a U.S. Forest Service long-term soil productivity study in the Carr Creek State Forest near Ellington, MO, to quantify treatment effects on...

  6. Establishing northern red oak on a degraded upland site in northeastern Pennsylvania: Influence of seedling pedigree and quality

    Science.gov (United States)

    Cornelia C. Pinchot; Thomas J. Hall; Scott E. Schlarbaum; Arnold M. Saxton; James. Bailey

    2017-01-01

    Enrichment plantings using large oak seedlings of regional sources may promote superior survival and growth compared to direct seeding or standard nursery seedling material. This study evaluated the survival and growth of planted 1-0 northern red oak (Quercus rubra L.) seedlings among 11 families and 3 seedling size classes (small, average, and...

  7. Comparison between the contribution of ellagitannins of new oak barrels and one-year-used barrels

    Directory of Open Access Journals (Sweden)

    Navarro María

    2016-01-01

    Full Text Available The influence of the botanical origin (French oak: Quercus petraea and American oak: Quercus alba, toasting level and if the barrel were new of previously used during one year have been studied. Results indicate that French oak released significant higher amounts of ellagitannins than American oak. Toasting level also exert a great influence. The higher the toasting level the lower the ellagitannin concentration in wines. Finally, the use during one year of the barrels drastically decreases the ellagitannin concentration in wines. Consequently, it can be concluded that the origin of oak, the toasting level and especially the previous use of the barrels have a very significant influence on the final ellagitannin concentration in wine, and probably on its sensory impact.

  8. A cortiça como sonda ambiental de metais pesados: um serviço sócio-ambiental prestado por montados de sobro e sobreirais The cork as environmental probe of heavy metals: a socio- environmental service done by “montados” with cork oaks and cork oak stands (Quercus suber L.

    Directory of Open Access Journals (Sweden)

    J. Ponte-e-Sousa

    2007-01-01

    causa em cada camada da cortiça de sobreiros dispersos na área onde vegetam, poder obter-se uma estimativa dos teores médios desses metais nos locais frequentemente caracterizados pela presença daquela árvore, poderá vir a ser muito interessante para um conhecimento mais profundo desta realidade.The long term life of cork oak and the capacity that “amadia” cork has to build annual layers (highly separable allowed to create the hypothesis of correlation between the chemical marks made in each growing layer and the environmental characteristics of the place where the cork oak grows. This would allow to build space and time distribution series every nine years, about the characteristic in study. This is somewhat alike some dendrometric procedures, but these ones are much more aggressive. The objective of this work was to study lead (II in cork by voltammetry, because this method is well recognized as having competitive vantages over other known methods already used. The methodology adopted was: bark extraction, acid-hot digestion in closed recipient and voltammetric analytical signal search. The main conclusion is the possible association of this technique as another socioenvironmental service that “montado” can provide, in order to evaluate the quality of mediterranean basin continental areas with cork oak tree, regarding lead contamination.

  9. Responses of evergreen and deciduous Quercus species to enhanced ozone levels

    Energy Technology Data Exchange (ETDEWEB)

    Calatayud, Vicent, E-mail: calatayud_viclor@gva.e [Instituto Universitario CEAM-UMH, Charles R. Darwin 14, Parc Tecnologic, 46980 Paterna, Valencia (Spain); Cervero, Julia; Calvo, Esperanza [Instituto Universitario CEAM-UMH, Charles R. Darwin 14, Parc Tecnologic, 46980 Paterna, Valencia (Spain); Garcia-Breijo, Francisco-Jose [Laboratorio de Anatomia e Histologia Vegetal ' Julio Iranzo' , Jardin Botanico, Universitat de Valencia, c/Quart 80, 46008 Valencia (Spain); Departamento de Ecosistemas Agroforestales, Escuela Tecnica Superior del Medio Rural y Enologia, Universidad Politecnica de Valencia, Avda. Blasco Ibanez 21, 46010 Valencia (Spain); Reig-Arminana, Jose [Departamento de Ecosistemas Agroforestales, Escuela Tecnica Superior del Medio Rural y Enologia, Universidad Politecnica de Valencia, Avda. Blasco Ibanez 21, 46010 Valencia (Spain); Sanz, Maria Jose [Instituto Universitario CEAM-UMH, Charles R. Darwin 14, Parc Tecnologic, 46980 Paterna, Valencia (Spain)

    2011-01-15

    Plants of one evergreen oak (Quercus ilex) and three deciduous oaks (Q. faginea, with small leaves; Q. pyrenaica and Q. robur, with large leaves) were exposed both to filtered air and to enhanced ozone levels in Open-Top Chambers. Q. faginea and Q. pyrenaica were studied for the first time. Based on visible injury, gas exchange, chlorophyll content and biomass responses, Q. pyrenaica was the most sensitive species, and Q. ilex was the most tolerant, followed by Q. faginea. Functional leaf traits of the species were related to differences in sensitivity, while accumulated ozone flux via stomata (POD{sub 1.6}) partly contributed to the observed differences. For risk assessment of Mediterranean vegetation, the diversity of responses detected in this study should be taken into account, applying appropriate critical levels. - Ozone tolerance overlapped with leaf traits in four Quercus species.

  10. Intrapopulation and Interpopulation Genetic Variation ofQuercus in Denmark in Denmark

    DEFF Research Database (Denmark)

    Siegismund, Hans Redlef; Jensen, Jan Svejgaard

    2001-01-01

    Native Danish oak stands are fragmented and decreasing because of the extensive use of foreign seed sources. Therefore, the population structure of natural Danish oak stands was analysed by means of six polymorphic enzyme loci. A total of 17 stands of Quercus robur L. (including an ‘‘outgroup......-Weinberg proportions, suggesting a low level of inbreeding. The differentiation of the Q. petraea and Q. robur populations was quanti. ed with Wright's F-statistics. The within-species component was populations was quanti. ed with Wright's -statistics. The within-species component was low, 0.022, re¿ ecting the wind...

  11. Utility of ITS sequence data for phylogenetic reconstruction of Italian Quercus spp.

    Science.gov (United States)

    Bellarosa, Rosanna; Simeone, Marco C; Papini, Alessio; Schirone, Bartolomeo

    2005-02-01

    Nuclear ribosomal DNA sequences encoding the 5.8S RNA and the flanking internal transcribed spacers (ITS1 and ITS2) were used to test the phylogenetic relationships within 12 Italian Quercus taxa (Fagaceae). Hypotheses of sequence orthology are tested by detailed inspection of some basic features of oak ITS sequences (i.e., general patterns of conserved domains, thermodynamic stability and predicted conformation of the secondary structure of transcripts) that also allowed more accurate sequence alignment. Analysis of ITS variation supported three monophyletic groups, corresponding to subg. Cerris, Schlerophyllodrys (=Ilex group sensu Nixon) and Quercus, as proposed by Schwarz [Feddes Rep., Sonderbeih. D, 1-200]. A derivation of the "Cerris group" from the "Ilex group" is suggested, with Q. cerris sister to the rest of the "Cerris group." Quercus pubescens was found to be sister to the rest of the "Quercus group." The status of hybrispecies of Q. crenata (Q. cerrisxQ. suber) and Q. morisii (Q. ilexxQ. suber) was evaluated and discussed. Finally, the phylogenetic position of the Italian species in a broader context of the genus is presented. The utility of the ITS marker to assess the molecular systematics of oaks is therefore confirmed. The importance of Italy as a region with a high degree of diversity at the population and genetic level is discussed.

  12. Detective Stories from Sherlock Holmes to Whitechapel

    OpenAIRE

    Feryal Çubukcu

    2015-01-01

    Detective Stories from Sherlock Holmes to Whitechapel Abstract The Victorian period in England was one of the most influential and important epochs in history. During Queen Victoria’s reign, England was arguably the most powerful nation in the world, setting standards for social, economic and industrial development. Among the rules of Victorian society were stringent codes pertaining to what was acceptable for men and women. Men were expected to hold decent jobs, marry respectable wom...

  13. Sherlock Holmes: From literary character to pop culture symbol

    OpenAIRE

    HULCOVÁ, Anna

    2013-01-01

    The bachelor thesis Sherlock Holmes: From literary character to pop culture symbol deals with the collection of sixty detective stories by Arthur Conan Doyle, the canon. The aim of the thesis is to highlight the aspects that contributed to the popularity of Sherlock Holmes and the series as such. The character of Sherlock Holmes became one of the most adapted literary characters, which is reflected in many areas of popular culture. Special attention is paid to the recent adaptations presentin...

  14. Sherlock Holmes: From literary character to pop culture symbol

    OpenAIRE

    HULCOVÁ, Anna

    2013-01-01

    The bachelor thesis Sherlock Holmes: From literary character to pop culture symbol deals with the collection of sixty detective stories by Arthur Conan Doyle, the canon. The aim of the thesis is to highlight the aspects that contributed to the popularity of Sherlock Holmes and the series as such. The character of Sherlock Holmes became one of the most adapted literary characters, which is reflected in many areas of popular culture. Special attention is paid to the recent adaptations presentin...

  15. Reciprocal link for a coupled Camassa-Holm type equation

    Science.gov (United States)

    Li, Nianhua; Zhang, Jinshun; Wu, Lihua

    2016-04-01

    A coupled Camassa-Holm type equation is linked to the first negative flow in a modified Drinfeld-Sokolov III hierarchy by a transformation of reciprocal type. Meanwhile the Lax pair and bi-Hamiltonian structure behaviors of this coupled Camassa-Holm type equation under the reciprocal transformation are analyzed.

  16. Attractor for a Viscous Coupled Camassa-Holm Equation

    Directory of Open Access Journals (Sweden)

    Tian Lixin

    2010-01-01

    Full Text Available The global existence of solution to a viscous coupled Camassa-Holm equation with the periodic boundary condition is investigated. We obtain the compact and bounded absorbing set and the existence of the global attractor for the viscous coupled Camassa-Holm equation in by uniform prior estimate.

  17. "There's a west wind coming" : Sherlock Holmes in Meiji Japan

    OpenAIRE

    堤林, 恵

    2015-01-01

    IntroductionJapan's Aspiration and the Reception of English Literature"Europeanization" and the Rising Tide of NationalismThe Standing of Detective FictionA Brief Overview of Sherlock Holmes TranslationsSherlock Holmes Refracted Through a PrismConclusion

  18. Asperger's in the Holmes Family

    Science.gov (United States)

    Altschuler, Eric L.

    2013-01-01

    I show that Mycroft Holmes (Sherlock Holmes' brother) is a formally described case of Asperger's syndrome a half century before Asperger's description of the syndrome. Further, given the genetic similarity and links between the brothers stated by Sherlock, this also cinches the same diagnosis for Sherlock.

  19. Asperger's in the Holmes Family

    Science.gov (United States)

    Altschuler, Eric L.

    2013-01-01

    I show that Mycroft Holmes (Sherlock Holmes' brother) is a formally described case of Asperger's syndrome a half century before Asperger's description of the syndrome. Further, given the genetic similarity and links between the brothers stated by Sherlock, this also cinches the same diagnosis for Sherlock.

  20. "There's a west wind coming" : Sherlock Holmes in Meiji Japan

    OpenAIRE

    堤林, 恵

    2015-01-01

    IntroductionJapan's Aspiration and the Reception of English Literature"Europeanization" and the Rising Tide of NationalismThe Standing of Detective FictionA Brief Overview of Sherlock Holmes TranslationsSherlock Holmes Refracted Through a PrismConclusion

  1. Characterization of Holmes in The Adventure of Speckled Band

    Institute of Scientific and Technical Information of China (English)

    CHEN Xiao-ling

    2015-01-01

    Sherlock Holmes is the fictional creation of Sir Arthur Conan Doyle. In The Adventure of the Speckled Band, Sir Arthur Conan Doyle has succeeded in creating the image of Sherlock Holmes. He is not only an excellent detective who is skillful in as⁃tute observation and deductive reasoning, but also the symbol of justice and wisdom.

  2. Reciprocal link for a coupled Camassa–Holm type equation

    Energy Technology Data Exchange (ETDEWEB)

    Li, Nianhua, E-mail: linianh@hqu.edu.cn; Zhang, Jinshun; Wu, Lihua

    2016-04-08

    Highlights: • We construct a reciprocal transformation for a coupled Camassa–Holm type equation proposed by Geng and Xue. • The transformed coupled Camassa–Holm type system is a reduction of the first negative flow in a modified Drinfeld–Sokolov III hierarchy. • The Lax pair and bi-Hamiltonian structure behaviors of the coupled Camassa–Holm type equation under the reciprocal transformation are analyzed. - Abstract: A coupled Camassa–Holm type equation is linked to the first negative flow in a modified Drinfeld–Sokolov III hierarchy by a transformation of reciprocal type. Meanwhile the Lax pair and bi-Hamiltonian structure behaviors of this coupled Camassa–Holm type equation under the reciprocal transformation are analyzed.

  3. A neighborhood analysis of the consequences of Quercus suber decline for regeneration dynamics in Mediterranean forests.

    Science.gov (United States)

    Ibáñez, Beatriz; Gómez-Aparicio, Lorena; Stoll, Peter; Ávila, José M; Pérez-Ramos, Ignacio M; Marañón, Teodoro

    2015-01-01

    In forests, the vulnerable seedling stage is largely influenced by the canopy, which modifies the surrounding environment. Consequently, any alteration in the characteristics of the canopy, such as those promoted by forest dieback, might impact regeneration dynamics. Our work analyzes the interaction between canopy neighbors and seedlings in Mediterranean forests affected by the decline of their dominant species (Quercus suber). Our objective was to understand how the impacts of neighbor trees and shrubs on recruitment could affect future dynamics of these declining forests. Seeds of the three dominant tree species (Quercus suber, Olea europaea and Quercus canariensis) were sown in six sites during two consecutive years. Using a spatially-explicit, neighborhood approach we developed models that explained the observed spatial variation in seedling emergence, survival, growth and photochemical efficiency as a function of the size, identity, health, abundance and distribution of adult trees and shrubs in the neighborhood. We found strong neighborhood effects for all the performance estimators, particularly seedling emergence and survival. Tree neighbors positively affected emergence, independently of species identity or health. Alternatively, seedling survival was much lower in neighborhoods dominated by defoliated and dead Q. suber trees than in neighborhoods dominated by healthy trees. For the two oak species, these negative effects were consistent over the three years of the experimental seedlings. These results indicate that ongoing changes in species' relative abundance and canopy trees' health might alter the successional trajectories of Mediterranean oak-forests through neighbor-specific impacts on seedlings. The recruitment failure of dominant late-successional oaks in the gaps opened after Q. suber death would indirectly favor the establishment of other coexisting woody species, such as drought-tolerant shrubs. This could lead current forests to shift into

  4. A neighborhood analysis of the consequences of Quercus suber decline for regeneration dynamics in Mediterranean forests.

    Directory of Open Access Journals (Sweden)

    Beatriz Ibáñez

    Full Text Available In forests, the vulnerable seedling stage is largely influenced by the canopy, which modifies the surrounding environment. Consequently, any alteration in the characteristics of the canopy, such as those promoted by forest dieback, might impact regeneration dynamics. Our work analyzes the interaction between canopy neighbors and seedlings in Mediterranean forests affected by the decline of their dominant species (Quercus suber. Our objective was to understand how the impacts of neighbor trees and shrubs on recruitment could affect future dynamics of these declining forests. Seeds of the three dominant tree species (Quercus suber, Olea europaea and Quercus canariensis were sown in six sites during two consecutive years. Using a spatially-explicit, neighborhood approach we developed models that explained the observed spatial variation in seedling emergence, survival, growth and photochemical efficiency as a function of the size, identity, health, abundance and distribution of adult trees and shrubs in the neighborhood. We found strong neighborhood effects for all the performance estimators, particularly seedling emergence and survival. Tree neighbors positively affected emergence, independently of species identity or health. Alternatively, seedling survival was much lower in neighborhoods dominated by defoliated and dead Q. suber trees than in neighborhoods dominated by healthy trees. For the two oak species, these negative effects were consistent over the three years of the experimental seedlings. These results indicate that ongoing changes in species' relative abundance and canopy trees' health might alter the successional trajectories of Mediterranean oak-forests through neighbor-specific impacts on seedlings. The recruitment failure of dominant late-successional oaks in the gaps opened after Q. suber death would indirectly favor the establishment of other coexisting woody species, such as drought-tolerant shrubs. This could lead current

  5. Sherlock (Holmes in Japanese (fan works [symposium

    Directory of Open Access Journals (Sweden)

    Lori Morimoto

    2017-03-01

    Full Text Available I explore the history of Japanese writing centered on Sherlock Holmes as a means of interrogating the 2014 BBC Sherlock pastiche John and Sherlock Casebook 1: Jon, zenchi renmei e iku (The stark naked league, written by Japanese Sherlockian Kitahara Naohiko for mainstream publication by the publishing house Hayakawa shobō. I argue that exploration of the Japanese (fan cultural contexts of Kitahara's book begins to reveal the limits of the Anglo-American-centered framework through which fan studies scholars explore fan/producer relationships.

  6. Numerical study of Peakons and k-Solitons of the Camassa-Holm and Holm-Hone equations

    Science.gov (United States)

    Popov, S. P.

    2011-07-01

    The spectral Fourier and Runge-Kutta methods are used to study the Camassa-Holm and Holm-Hone equations numerically. Numerical results for problems with initial data leading to the generation and interaction of peakons and k-solitons are discussed.

  7. Thinning to improve growth, bole quality, and forest health in an Inonotus hispidus-infected, red oak-sweetgum stand in the Mississippi Delta: 10-year results

    Science.gov (United States)

    James S. Meadows; Theodor D. Leininger; David Montwé; T. Evan Nebeker

    2013-01-01

    A 55-year-old red oak-sweetgum (Quercus spp.- Liquidambar styraciflua) stand on the Delta National Forest in western Mississippi was subjected to a combination of low thinning and improvement cutting in 1997. Special emphasis was placed on removing all red oaks infected with Inonotus hispidus, a canker decay...

  8. Mass loss and nutrient concentrations of buried wood as a function of organic matter removal, soil compaction, and vegetation control in a regenerating oak-pine forest

    Science.gov (United States)

    Felix Ponder; John M. Kabrick; Mary Beth Adams; Deborah S. Page-Dumroese; Marty F. Jurgensen

    2017-01-01

    Mass loss and nutrient concentrations of northern red oak (Quercus rubra) and white oak (Q. alba) wood stakes were measured 30 months after their burial in the upper 10 cm of soil in a regenerating forest after harvesting and soil disturbance. Disturbance treatments were two levels of organic matter (OM) removal (only...

  9. Influence of planting stocks on the survival and growth of Nuttall and cherrybark oak planted on lands damaged by Hurricane Katrina

    Science.gov (United States)

    Derek K. Alkire; James C. Rainer; Andrew B. Self; Andrew W. Ezell; Andrew J. Londo; Emily B. Schultz

    2013-01-01

    Bare-root, container, and root production method (RPMTM) seedlings of Nuttall oak (Quercus texana Buckley) and cherrybark oak (Q. pagoda Ell.) were planted on lands damaged by Hurricane Katrina in southern Mississippi to compare the height growth, groundline diameter (GLD) growth, and survival of the...

  10. Resprouting of Quercus suber in NE Spain after fire

    Energy Technology Data Exchange (ETDEWEB)

    Pausas, J.G. [Centro de Estudios Ambientales del Mediterraneo, Valencia (Spain)

    1997-11-01

    Many Mediterranean species have evolved strategies that allow them to survive periodic wildfires. Quercus suber trees resprout after fire, some from stem buds and others from basal buds only. In the former case the canopy recovers quickly. In the latter case the stem dies but the tree survives and regrows from basal sprouts. The probability of stem death and the degree of height recovery were studied after a fire in a Q. suber forest in NE Spain using logistic regression analysis. The results suggest that most trees survive after fire; the probability of stem death is negatively related to tree diameter; and recovery is positively related to tree diameter and to bark thickness. Implication for management and conservation of cork-oak forests are discussed 22 refs, 2 figs, 3 tabs

  11. An approach to cork oak forest management planning: a case study in southwestern Portugal

    OpenAIRE

    A. Costa; A.C. Oliveira; Vidas, F.; J. G. Borges

    2010-01-01

    This paper presents results of research aiming at the development of tools that may enhance cork oak (Quercus suber L.) forest management planning. Specifically, it proposes an hierarchical approach that encompasses the spatial classification of a cork oak forest and the temporal scheduling of cork harvests. The use of both geographical information systems and operations research techniques is addressed. Emphasis is on the achievement of cork even flow objectives. Resu...

  12. soil carbon pools within oak forest is endangered by global climate change in central mexico

    Science.gov (United States)

    García-Oliva, Felipe; Merino, Agustín; González-Rodriguez, Antonio; Chávez-Vergara, Bruno; Tapia-Torres, Yunuen; Oyama, Ken

    2016-04-01

    Forest soil represents the main C pool in terrestrial ecosystems. In particular, temperate forest ecosystems play an important role in the C budget among tropical countries, such as Mexico. For example, the temperate forest ecosystem contains higher C contents on average (295 Mg C ha-1) than the soil C associated with other ecosystems in Mexico (between 56 to 287 Mg C ha-1). At a regional scale, oak forest has the highest C content (460 Mg C ha-1) among the forest ecosystem in Michoacán State at Central Mexico. At the local scale, the soil C content is strongly affected by the composition of organic matter produced by the plant species. The oak species are very diverse in Mexico, distributed within two sections: Quercus sensu stricto and Lobatae. The oak species from Quercus s.s. section produced litterfall with lower concentrations of recalcitrant and thermostable compounds than oak species from Lobatae section, therefore the soil under the former species had higher microbial activity and nutrient availability than the soil under the later species. However, the forest fragment with higher amount of oak species from Quercus s.s. section increases the amount of soil C contents. Unfortunately, Quercus species distribution models for the central western region of Mexico predict a decrease of distribution area of the majority of oak species by the year 2080, as a consequence of higher temperatures and lower precipitation expected under climate change scenarios. Additionally to these scenarios, the remnant oak forest fragments suffer strong degradation due to uncontrolled wood extraction and deforestation. For this reason, the conservation of oak forest fragments is a priority to mitigate the greenhouse gases emission to the atmosphere. In order to enhance the protection of these forest fragments it is required that the society identify the ecosystem services that are provided by these forest fragments.

  13. Da Sherlock Holmes kom til Danmark første gang

    DEFF Research Database (Denmark)

    Lauridsen, Palle Schantz

    2011-01-01

    Præsentation og analyse af Holmes-figurens udvikling i populærkulturen med udgangspunkt i det succesfulde teaterstykke "Sherlock Holmes" fra 1901......Præsentation og analyse af Holmes-figurens udvikling i populærkulturen med udgangspunkt i det succesfulde teaterstykke "Sherlock Holmes" fra 1901...

  14. Sherlock Holmes: Uppruni persónunar

    OpenAIRE

    2014-01-01

    Í þessari ritgerð mun ég fjalla ítarlega um skáldsagnapersónuna Sherlock Holmes, hvað gerir hann svona sérstakan miðað við aðrar frægar skáldsagnapersónur, hver er ástæða þess að hann hefur haldið vinsældum sínum eins lengi og raun ber vitni og á hverjum hann er í rauninni byggður á. Það kemur á óvart í raun og veru hversu margir hafa komið við sögu við að búa til þá ímynd sem við höfum af Sherlock Holmes í dag. Það er alls ekki aðeins höfundur bókanna, Arthur Conan Doyle sem kemur þar að hel...

  15. Oliver Wendell Holmes. "Miscuit utile dulci".

    Science.gov (United States)

    Lindskog, G E

    1974-12-01

    The life of Oliver Wendell Holmes was selected as the subject for a lecture in the 1974 History of Medicine series at Yale University School of Medicine because, as the Latin subtitle of the essay suggests, he represents a fortunate and uncommon, but by no means unique, synthesis of the practical and aesthetic, of science and the humanities. An attempt has been made by the lecturer, employing frequent, but brief, excerpts from the works of several disinguished biographers as well as Doctor Holmes' own lectures, medical papers, essays and poems to delineate the elite heritage and the events that led this complex person transiently into the sudy of law, the profession in which his older son reached the pinnacle of the U.S. Supreme Court, and finally into medicine where a short period of private practice was followed by more than three decades of distinguished teaching is anatomy. His lifetime (1809-1894) spanned most of the nineteenth century, in the literary hisory of which he played a significant role. His writings reveal a remarkable, and sometimes prophetic, appreciation of the impact that burgeoning science and evolving social pressures and changes would have on the teaching and practice of medicine in the future-our present.

  16. Analysis of the Characterization of Sherlock Holmes

    Institute of Scientific and Technical Information of China (English)

    张静涵

    2014-01-01

    本文分析《斑点带子案》中夏洛克·福尔摩斯的人物塑造。基于解构主义,探究福尔摩斯与众不同且充满魅力的性格。并且文中解码福尔摩斯如何从不足的资料中破案。通过该侦探小说中二元对立组中不同人物形象的刻画,体现出福尔摩斯性格中的闪光点。此外,本文阐释了福尔摩斯存在一个世纪之久的原因,为广大读者提供赏析福尔摩斯性格魅力的机会。%This paper analyzes the characterization of Sherlock Holmes in The Adventure of the Speckled Band. It explores the special characters of Holmes’based on the theory of Deconstruction. And the paper decodes how he solves a case from insufficient data. The different characterizations of bi-nary oppositions in this detective story reflect some shining characters of Holmes’. Moreover,it explains why Holmes could exist more than a century, which offers readers a chance to appreciate the glamour of Holmes’charac-ters.

  17. Sherlock Holmes: an expert's view of expertise.

    Science.gov (United States)

    André, Didierjean; Fernand, Gobet

    2008-02-01

    In recent years, there has been an intense research effort to understand the cognitive processes and structures underlying expert behaviour. Work in different fields, including scientific domains, sports, games and mnemonics, has shown that there are vast differences in perceptual abilities between experts and novices, and that these differences may underpin other cognitive differences in learning, memory and problem solving. In this article, we evaluate the progress made in the last years through the eyes of an outstanding, albeit fictional, expert: Sherlock Holmes. We first use the Sherlock Holmes character to illustrate expert processes as described by current research and theories. In particular, the role of perception, as well as the nature and influence of expert knowledge, are all present in the description of Conan Doyle's hero. In the second part of the article, we discuss a number of issues that current research on expertise has barely addressed. These gaps include, for example, several forms of reasoning, the influence of emotions on cognition, and the effect of age on experts' knowledge and cognitive processes. Thus, although nearly 120-year-old, Conan Doyle's books show remarkable illustrations of expert behaviour, including the coverage of themes that have mostly been overlooked by current research.

  18. Stimulation of Armillaria rhizomorph growth by oak root fungi

    Directory of Open Access Journals (Sweden)

    Hanna Kwaśna

    2014-08-01

    Full Text Available Thirty one different genera of fungi were isolated from the wood of roots of 5O·year·old oak (Quercus robur. The most frequently isolated fungi were: Mycelium radicis atrovirens alpha (MRAA, Clonostachys sp. and Penicillium daleae, Beauveria bassiana, Clonostachys sp., Cryplosporiopsis rodicicolo, Geotrichum candidum, Mortierella vinacea, MRAA, P. daleae, P. janczewskii P. spinulosum, Sporothrix schenckii and Tolypocladium niveum significantly enhanced Armillaria mellea rhizomorph initiation and growth from oak branch segments in vitro. The biggest stimulation effect was noticed when the dematiaceous hyphomycetes, e.g. MRAA, P. dimorphospora and S. schenckii were studied.

  19. An evaluation of hardwood fuel models for planning prescribed fires in oak shelterwood stands

    Science.gov (United States)

    Patrick H. Brose

    2017-01-01

    The shelterwood burn technique is becoming more accepted and used as a means of regenerating eastern mixed-oak (Quercus spp.) forests on productive upland sites. Preparation is important to successfully implement this method; part of that preparation is selecting the proper fuel model (FM) for the prescribed fire. Because of the mix of leaf litter...

  20. Leaf Biomass and Acorn Production in a Thinned 30-Year-Old Cherrybark Oak Plantation

    Science.gov (United States)

    Erika L. Stelzer; Jim L. Chamgers; James S. Meadows; Kenneth F. Ribbeck

    2004-01-01

    Objectives of this study were to determine the effects of two levels of thinning on leaf biomass and acorn production of cherrybark oak (Quercus pagoda Raf.). To evaluate the effects of thinning 2 years after treatment, treatment plots were selected and blocked on the basis of initial stocking levels. Two levels of stocking and a control were...

  1. The Effect of Low Oxygen Stress on Phytophthora cinnamomi Infection and Disease of Cork Oak Roots

    Science.gov (United States)

    Karel A. Jacobs; James D. MacDonald; Alison M. Berry; Laurence R. Costello

    1997-01-01

    The incidence and severity of Phytophthora cinnamomi Rands root disease was quantified in cork oak (Quercus suber L.) roots subjected to low oxygen (hypoxia) stress. Seedling root tips were inoculated with mycelial plugs of the fungus and incubated in ≤1, 3-4, or 21 percent oxygen for 5 days. Ninety-four percent of roots...

  2. Approaches to restoration of oak forests on farmed lowlands of the Mississippi River and its tributaries

    Science.gov (United States)

    Emile S. Gardiner; Daniel C. Dey; John A. Stanturf; Brian Roy. Lockhart

    2010-01-01

    The lowlands associated with the Mississippi River and its tributaries historically supported extensive broadleaf forests that were particularly rich in oak (Quercus spp.) species. Beginning in the 1700s, deforestation for agriculture substantially reduced the extent of the original forest, and fragmented the remainder into small parcels. More...

  3. Herbivore-induced shifts in carbon and nitrogen allocation in red oak seedlings

    Science.gov (United States)

    Christopher J. Frost; Mark D. Hunter

    2008-01-01

    A dual-isotope, microcosm experiment was conducted with Quercus rubra (red oak) seedlings to test the hypothesis that foliar herbivory would increase belowground carbon allocation (BCA), carbon (C) rhizodeposition and nitrogen (N) uptake. Plant BCA links soil ecosystems to aboveground processes and can be affected by insect herbivores, though the...

  4. Effect of acorn size on development of northern red oak 1-0 seedlings

    Science.gov (United States)

    Paul P. Kormanik; Shi-Jean S. Sung; T.L. Kormanik; S.E. Schlarbaum; Stanley J. Zarnoch

    1998-01-01

    The effect of acorn size on seedling development was determined for 20 northern red oak (Quercus rubra L.) mother tree selections from the USDA Forest Service's Eastern Tennessee Watauga seed orchard. Acorns from each mother tree were visually separated into three size groups, weighed, and sown separately in forest nurseries located in Georgia,...

  5. Large Drought-Induced Variations in Oak Leaf Volatile Organic Compound Emissions during PINOT NOIR 2012

    Science.gov (United States)

    Leaf-level isoprene and monoterpene emissions were collected and analyzed from five of the most abundant oak (Quercus) species in Central Missouri’s Ozarks Region in 2012 during PINOT NOIR (Particle Investigations at a Northern Ozarks Tower ‐ NOx, Oxidants, Isoprene Research). Ju...

  6. High rates of gene flow by pollen and seed in oak populations across Europe

    NARCIS (Netherlands)

    Gerber, S.; Chadoeuf, J.; Gugerli, F.; Lascoux, M.; Buiteveld, J.; Cottrell, J.; Dounavi, A.; Fineschi, S.; Forrest, L.; Fogelqvist, J.; Goicoechea, P.G.; Jensen, J.S.; Salvini, D.; Vendramin, G.G.; Kremer, A.

    2014-01-01

    Gene flow is a key factor in the evolution of species, influencing effective population size, hybridisation and local adaptation. We analysed local gene flow in eight stands of white oak (mostly Quercus petraea and Q. robur, but also Q. pubescens and Q. faginea) distributed across Europe. Adult tree

  7. Leaf area compounds height-related hydraulic costs of water transport in Oregon White Oak trees.

    Science.gov (United States)

    N. Phillips; B. J. Bond; N. G. McDowell; Michael G. Ryan; A. Schauer

    2003-01-01

    The ratio of leaf to sapwood area generally decreases with tree size, presumably to moderate hydraulic costs of tree height. This study assessed consequences of tree size and leaf area on water flux in Quercus garryana Dougl. ex. Hook (Oregon White Oak), a species in which leaf to sapwood area ratio increases with tree size. We tested hypotheses that...

  8. The dynamics of cork oak systems in Portugal: the role of ecological and land use factors

    NARCIS (Netherlands)

    Acácio, V.C.

    2009-01-01

    Vegetation degradation and desertification occur in many semiarid ecosystems worldwide, particularly in the Western Mediterranean Basin. A peculiar semiarid Mediterranean land use system dominates the landscape of southern Portugal where cork oak (Quercus suber) is the main tree species. This system

  9. Authorship and authenticity in Sherlock Holmes pastiches

    Directory of Open Access Journals (Sweden)

    Sanna Nyqvist

    2017-03-01

    Full Text Available Rewritings and adaptations of the Sherlock Holmes stories are traditionally called pastiches among fandom. This article juxtaposes that established use with the literary critical notion of pastiche as imitation of style, and shows how stylistic affinity to the originals produces complex effects in the imitations. The article identifies two main strands in the pastiches: one that aims to correct the mistakes and fill in the gaps in the original stories, and one that supplements the canon with stories Watson left untold. Balancing among homage, criticism, and usurpation, the pastiches comment on the original story world and its cultural context, and engage in fictions of authorship to account for the apparent inauthenticity of the retellings.

  10. Detective Stories from Sherlock Holmes to Whitechapel

    Directory of Open Access Journals (Sweden)

    Feryal Çubukcu

    2015-12-01

    Full Text Available Detective Stories from Sherlock Holmes to Whitechapel Abstract The Victorian period in England was one of the most influential and important epochs in history. During Queen Victoria’s reign, England was arguably the most powerful nation in the world, setting standards for social, economic and industrial development. Among the rules of Victorian society were stringent codes pertaining to what was acceptable for men and women. Men were expected to hold decent jobs, marry respectable women, and create the next generation of proper British citizens. Women were raised to marry, breed virtuous English children, and live quietly in the confines of the household. As Elaine Showalter (1987 says Victorian households had different spheres for men and women. There were certain behavioral norms for men and women that were standard practice for asserting one’s proper gender codes. In his 1995 book Victorian Masculinities, Herbert Sussman identifies, within Victorian men’s writing, a method of constructing masculinity that opposes the dominant English model of manliness based on bourgeois domestic matrimony. During the first half of the Victorian period, normative masculinity required a man to master his psychic energy by establishing a bourgeois domestic identity founded on matrimony. However, this concept translates into the bachelordom plot, wherein male desire finds an appropriate outlet in a sidekick rather than a wife, thus, under the terms of popular middle-class belief, permanently affirming masculinity. When we come to 2010s a bestseller Whitechapel hinges on the same lone detective trying to pursue the killers and criminals. The purpose of this paper is to probe and grapple with the similarities and dissimilarities the detective genre from Sherlock Holmes to Whitechapel by focusing on the detective himself, the crime types, criminals- their motives and ethnic origins-, masculinity, and male-male bonding.

  11. First Report of the Winter Moth Operophtera brumata on Quercus canariensis and Q. afares in North West of Tunisia

    OpenAIRE

    Yaussra Mannai; Olfa Ezzine; Said Nouira; Mohamed Lahbib Ben Jamâa

    2015-01-01

    Operophtera brumata is a newly detected moth in Tunisia. It is considered the most important leaffeeding pest infesting fruit trees and deciduous forests in northern Europe. A recent outbreak of the winter moths was observed between 2009 and 2014 in oak forest in the North West of Tunisia with a peak density in 2010-2011. O. brumata was observed on totally defoliated Quercus canariensis and Q. afares. In this paper, we present a first report of this pest.

  12. The Autistic Detective: Sherlock Holmes and his Legacy

    Directory of Open Access Journals (Sweden)

    Sonya Freeman Loftis

    2014-12-01

    Full Text Available Sherlock Holmes has long been rumored to be on the autism spectrum. Yet the significance of the great detective's autism "diagnosis" has been largely overlooked. While it would be impossible to diagnose a fictional character with a neurological difference, it says something about the way that the public imagines autism that Holmes is consistently imagined and described as a person on the spectrum. Indeed, Conan Doyle's character popularized the stereotype of the detective with autistic traits, thus perpetuating several common tropes about autism. Emulating Conan Doyle's famous tales, contemporary crime fiction frequently creates detective characters with autistic characteristics. For example, popular television shows such as Criminal Minds present detectives with autistic traits who are clearly constructed to remind audiences of Holmes. While figures such as Spenser Reid (and other crime fighters following in Holmes's shadow may seem to counteract fears of people with cognitive disabilities as deviant, criminal, or dangerous, they may actually reinforce those stereotypes.

  13. The Chemical Adventures of Sherlock Holmes: Autopsy in Blue

    Science.gov (United States)

    Waddell, Thomas G.; Rybolt, Thomas R.

    2004-01-01

    A chemical mystery with an emphasis on qualitative inorganic analysis, forensic chemistry and medicinal substances is discussed. The mystery is solved by Sherlock Holmes with the help of clues provided.

  14. The Chemical Adventures of Sherlock Holmes: The Blackwater Escape.

    Science.gov (United States)

    Waddell, Thomas G.; Rybolt, Thomas R.

    2003-01-01

    Presents a mystery based on the well-known characters, Sherlock Holmes and Dr. Watson. Emphasizes qualitative inorganic analysis, laboratory observations, and oxidation-reduction processes. (Author/YDS)

  15. The Chemical Adventures of Sherlock Holmes: The Baker Street Burning.

    Science.gov (United States)

    Waddell, Thomas G.; Rybolt, Thomas R.

    1998-01-01

    Presents the ninth story in a series of chemical mysteries with emphasis on forensic chemistry, physical properties, and qualitative organic analysis. The mystery centers around the adventures of Sherlock Holmes. (DDR)

  16. The Chemical Adventures of Sherlock Holmes: Autopsy in Blue

    Science.gov (United States)

    Waddell, Thomas G.; Rybolt, Thomas R.

    2004-01-01

    A chemical mystery with an emphasis on qualitative inorganic analysis, forensic chemistry and medicinal substances is discussed. The mystery is solved by Sherlock Holmes with the help of clues provided.

  17. The Chemical Adventures of Sherlock Holmes: The Blackwater Escape.

    Science.gov (United States)

    Waddell, Thomas G.; Rybolt, Thomas R.

    2003-01-01

    Presents a mystery based on the well-known characters, Sherlock Holmes and Dr. Watson. Emphasizes qualitative inorganic analysis, laboratory observations, and oxidation-reduction processes. (Author/YDS)

  18. Revalidating Sherlock Holmes for a role in medical education.

    Science.gov (United States)

    Levine, David

    2012-04-01

    Sir Arthur Conan Doyle endowed Sherlock Holmes with extraordinary skills that Dr Watson and others found incomprehensible until Holmes gave explanations, often in the form of memorable maxims and short monologues. Intentionally or not, Doyle left us crime-solving precepts that still inform aspects of medical practice. Experienced clinicians share with Holmes the dilemma of how to make complex, often unconscious, capability accessible to novices. Doctors still invoke Holmes's methods in clinical contexts, but the validity of some of the parallels has been challenged and quoting the more popular sayings has been equated with conceit. This paper examines how the use of selected maxims and monologues can help to link abstract principles and live context in a credible way in order to make aspects of clinical reasoning and professional behaviour more accessible and memorable.

  19. The Chemical Adventures of Sherlock Holmes: The Baker Street Burning.

    Science.gov (United States)

    Waddell, Thomas G.; Rybolt, Thomas R.

    1998-01-01

    Presents the ninth story in a series of chemical mysteries with emphasis on forensic chemistry, physical properties, and qualitative organic analysis. The mystery centers around the adventures of Sherlock Holmes. (DDR)

  20. 六盘山区橡木与欧美主要橡木理化特征的比较研究%Comparison of Physiochemical Properties of Oaks from Liupan Mountain Regions of Ningxia and European and American Oaks

    Institute of Scientific and Technical Information of China (English)

    马文平; 孙雅; 倪志婧; 王薇; 宋长冰

    2016-01-01

    宁夏六盘山区辽东栎(Quercus liaotungensis Koidz)是我国重要的橡木资源,目前对其在葡萄酒酿造方面的应用研究较少。以宁夏六盘山区辽东栎和美国橡木、法国橡木为材料,采用电镜与化学成分分析方法,研究不同产地橡木木质结构和主要化学成分的差异。结果表明,法国橡木导管孔径大、纹理较粗,质地疏松;辽东栎纹理清晰细密,导管孔径小,富含侵填体,质地紧实,与美国橡木接近,因此辽东栎可采用美国橡木的制桶工艺。通过化学成分分析发现,美国橡木水分含量显著高于法国橡木和辽东栎,辽东栎的灰分、纤维素含量显著高于法国橡木与美国橡木,但单宁含量与美国橡木无显著差异,均显著低于法国橡木。木质素含量与其他产地橡木没有显著差异,说明辽东栎陈酿的葡萄酒具有极大释放芳香的潜力。%Quercus liaotungensis Koidzas from Liupan Mountain regions is the main oak resource in China. However, the research on its appli-cation in wine-making industry is rare. In this study, Quercus liaotungensis Koidz from Liupan Mountain regions, and American and French oaks were used as the research objects. The difference in wood structure and main chemical components among oaks from different regions was investigated by scanning electron microscope and chemistry assay. The results showed that, French oak had large vessel diameter, coarse grain of wood, and loose wood texture;Quercus liaotungensis Koidz had clear grains, smaller vessel diameter and rich oak tyloses, and its wood tex-ture is compaction, more close to American oaks. Accordingly, the production process of oak barrel with Quercus liaotungensis Koidz can be the same as that with American oaks. Chemical composition assay indicated that moisture content of American oak was higher than Quercus li-aotungensis Koidz and French oaks, but ash and cellulose content of Quercus

  1. Mortality due to Japanese oak wilt disease and surrounding forest compositions

    Directory of Open Access Journals (Sweden)

    Michio Oguro

    2015-12-01

    Full Text Available Japanese oak wilt (Raffaelea quercivora is a vector-borne disease transmitted by the flying ambrosia beetle, Platypus quercivorus, and causes mass mortality in the fagaceous species of Japan. The data described in this article are available in Mendeley Data, DOI: 10.17632/xwj98nb39r.1 [1] and include the mortality status of 1089 Quercus crispula and 846 Quercus serrata trees and surrounding forest conditions. The findings using this dataset were published in M. Oguro, S. Imahiro, S. Saito, T. Nakashizuka, Relative importance of multiple scale factors to oak tree mortality due to Japanese oak wilt disease, For. Ecol. Manag. (2015 doi:10.1016/j.foreco.2015.07.016 [2].

  2. Mortality due to Japanese oak wilt disease and surrounding forest compositions.

    Science.gov (United States)

    Oguro, Michio; Imahiro, Sawako; Saito, Shoichi; Nakashizuka, Tohru

    2015-12-01

    Japanese oak wilt (Raffaelea quercivora) is a vector-borne disease transmitted by the flying ambrosia beetle, Platypus quercivorus, and causes mass mortality in the fagaceous species of Japan. The data described in this article are available in Mendeley Data, DOI: 10.17632/xwj98nb39r.1 [1] and include the mortality status of 1089 Quercus crispula and 846 Quercus serrata trees and surrounding forest conditions. The findings using this dataset were published in M. Oguro, S. Imahiro, S. Saito, T. Nakashizuka, Relative importance of multiple scale factors to oak tree mortality due to Japanese oak wilt disease, For. Ecol. Manag. (2015) doi:10.1016/j.foreco.2015.07.016 [2].

  3. Applying Hotspot Detection Methods in Forestry: A Case Study of Chestnut Oak Regeneration

    Directory of Open Access Journals (Sweden)

    Songlin Fei

    2010-01-01

    Full Text Available Hotspot detection has been widely adopted in health sciences for disease surveillance, but rarely in natural resource disciplines. In this paper, two spatial scan statistics (SaTScan and ClusterSeer and a nonspatial classification and regression trees method were evaluated as techniques for identifying chestnut oak (Quercus Montana regeneration hotspots among 50 mixed-oak stands in the central Appalachian region of the eastern United States. Hotspots defined by the three methods had a moderate level of conformity and revealed similar chestnut oak regeneration site affinity. Chestnut oak regeneration hotspots were positively associated with the abundance of chestnut oak trees in the overstory and a moderate cover of heather species (Vaccinium and Gaylussacia spp. but were negatively associated with the abundance of hayscented fern (Dennstaedtia punctilobula and mountain laurel (Kalmia latiforia. In general, hotspot detection is a viable tool for assisting natural resource managers with identifying areas possessing significantly high or low tree regeneration.

  4. CHANGES IN VOLATILE COMPOSITION AND SENSORY PROPERTIES OF VUGAVA WINES AGED IN CROATIA OAK BARRELS

    Directory of Open Access Journals (Sweden)

    Stanka HERJAVEC

    2001-09-01

    Full Text Available Vugava musts were fermented in medium-toasted Croatian barrique barrels (225 L made from Quercus petrea and Q. robur oak wood. The oak species used in this research infl uenced the specifi c change of the aroma structure of Vugava wines. During the age period the increase in the concentration of cis and trans oaklactons, guaiacol, eugenol, furfural and 5-methylfurfural was noted. Wines fermented and aged in Q. petrea barrels have higher concentrations of most volatile phenols compared to wines from Q. robur oak wood. From the organoleptic point of view this study suggested that fermentation and on the lees ageing production method in Croatian oak barrels positively infl uenced the quality of Vugava wines where best results were achieved by use of Q. petrea oak wood.

  5. Chloroplast DNA Diversity of Oak Species in Eastern Romania

    Directory of Open Access Journals (Sweden)

    Ioan Calin MOLDOVAN

    2010-12-01

    Full Text Available The chloroplast DNA of 34 sessile oak (Quercus petraea and 27 pedunculate oak (Q. robur populations covering the entire natural distribution of the two oak species in Eastern Romania was investigated using four large regions of the chloroplast genome by PCR and RFLP technique. A total of seven chloroplast DNA haplotypes sensu lato have been observed by analysing 305 mature trees. However, due to the high resolution of the electrophoresis method a total of 22 chloroplast variants could have been detected, with new mutations and fragment combinations in two of the amplified regions: psbC/trnD and trnT/trnF. All of the haplotypes belong to the phylogenetic lineages A and E, which originate from the Balkan Peninsula. Most of genetic diversity is distributed among populations (GST=0.779. The chloroplast DNA haplotypes are shared by the two oak species. Different dispersal abilities may explain the higher value of genetic differentiation among populations in sessile oak than in pedunculate oak.

  6. Tit-Bits, New Journalism, and early Sherlock Holmes fandom

    Directory of Open Access Journals (Sweden)

    Ann K. McClellan

    2017-03-01

    Full Text Available The Strand's more popular sister magazine, Tit-Bits, played a significant role in establishing Sherlock Holmes as a literary and cultural icon, particularly through its use of participatory practices, cross-promotion, and transmedia storytelling. I argue that Tit-Bits' late 19th-century New Journalism techniques like contests and prizes, inquiry columns, correspondence, and internal advertising fostered a corporately devised participatory fandom that directly contributed to Sherlock Holmes's popularity. Tit-Bits audiences were invited and encouraged to imagine new scenarios for their favorite character that were validated through publication. Such practices not only created a unique identity for Sherlock Holmes fandom but also directly contributed to the creation and maintenance of Holmes's fictional world. With fandom studies reaching more and more audiences—both academic and popular—historicizing early fan practices like the early publication and reception of the Sherlock Holmes stories provides important insight into how audiences have historically responded to, and interacted with, fictional characters, and how they helped sustain and expand those characters' fictional worlds.

  7. Densities of Agrilus auroguttatus and Other Borers in California and Arizona Oaks

    Directory of Open Access Journals (Sweden)

    Laurel J. Haavik

    2014-03-01

    Full Text Available We investigated within-tree population density of a new invasive species in southern California, the goldspotted oak borer, Agrilus auroguttatus Schaeffer (Coleoptera: Buprestidae, with respect to host species and the community of other borers present. We measured emergence hole densities of A. auroguttatus and other borers on the lower stem (bole of naïve oaks at 18 sites in southern California and on co-evolved oaks at seven sites in southeastern Arizona. We sampled recently dead oaks in an effort to quantify the community of primary and secondary borers associated with mortality—species that were likely to interact with A. auroguttatus. Red oaks (Section Lobatae produced greater densities of A. auroguttatus than white oaks (Section Quercus. On red oaks, A. auroguttatus significantly outnumbered native borers in California (mean ± SE of 9.6 ± 0.7 versus 4.5 ± 0.6 emergence holes per 0.09 m2 of bark surface, yet this was not the case in Arizona (0.9 ± 0.2 versus 1.1 ± 0.2 emergence holes per 0.09 m2. In California, a species that is taxonomically intermediate between red and white oaks, Quercus chrysolepis (Section Protobalanus, exhibited similar A. auroguttatus emergence densities compared with a co-occurring red oak, Q. kelloggii. As an invasive species in California, A. auroguttatus may affect the community of native borers (mainly Buprestidae and Cerambycidae that feed on the lower boles of oaks, although it remains unclear whether its impact will be positive or negative.

  8. Sympatric parallel diversification of major oak clades in the Americas and the origins of Mexican species diversity.

    Science.gov (United States)

    Hipp, Andrew L; Manos, Paul S; González-Rodríguez, Antonio; Hahn, Marlene; Kaproth, Matthew; McVay, John D; Avalos, Susana Valencia; Cavender-Bares, Jeannine

    2017-09-18

    Oaks (Quercus, Fagaceae) are the dominant tree genus of North America in species number and biomass, and Mexico is a global center of oak diversity. Understanding the origins of oak diversity is key to understanding biodiversity of northern temperate forests. A phylogenetic study of biogeography, niche evolution and diversification patterns in Quercus was performed using 300 samples, 146 species. Next-generation sequencing data were generated using the restriction-site associated DNA (RAD-seq) method. A time-calibrated maximum likelihood phylogeny was inferred and analyzed with bioclimatic, soils, and leaf habit data to reconstruct the biogeographic and evolutionary history of the American oaks. Our highly resolved phylogeny demonstrates sympatric parallel diversification in climatic niche, leaf habit, and diversification rates. The two major American oak clades arose in what is now the boreal zone and radiated, in parallel, from eastern North America into Mexico and Central America. Oaks adapted rapidly to niche transitions. The Mexican oaks are particularly numerous, not because Mexico is a center of origin, but because of high rates of lineage diversification associated with high rates of evolution along moisture gradients and between the evergreen and deciduous leaf habits. Sympatric parallel diversification in the oaks has shaped the diversity of North American forests. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  9. Diplodia quercivora sp. nov.: a new species of Diplodia found on declining Quercus canariensis trees in Tunisia.

    Science.gov (United States)

    Linaldeddu, Benedetto T; Franceschini, Antonio; Alves, Artur; Phillips, Alan J L

    2013-01-01

    During a study of the species of Botryosphaeriaceae associated with oak decline in Tunisia, a large collection of Diplodia strains were isolated from Quercus afares, Q. canariensis and Q. suber trees showing a progressive dieback of shoots and branches, trunk canker and exudates and collar rot. Most of the isolates were identified as Diplodia corticola, while two isolates from Q. canariensis were morphologically and phylogenetically (ITS and tef1-α sequences data) distinct from all other known species of Diplodia. They are described here as Diplodia quercivora sp. nov. In addition, phylogenetic analyses showed for the first time the existence of two distinct lineages within D. corticola. In artificial inoculation experiments, D. quercivora caused necrotic lesions on bark and wood of three Mediterranean oak species, Q. ilex, Q. pubescens and Q. suber. In particular, among the oak species tested, Q. pubescens was the most susceptible.

  10. Growth And Development Of First-Year Nursery-Grown White Oak Seedlings Of Individual Mother Trees

    Science.gov (United States)

    Shi-Jean S. Sung; Paul P. Kormanik; Stanley J. Zarnoch

    2002-01-01

    Abstract - White oak (Quercus alba L.) acorns from individual mother trees at Arrowhead Seed Orchard (ASO, Milledgeville, GA), Beech Creek Seed Orchard (BSO, Murphy, NC), and Savannah River Site (SRS, Aiken, SC) were sown in December 1999 at Whitehall Experiment Forest Nursery (Athens, GA). All 6 mother trees from BSO were grafted...

  11. After 25 years, what does the Pennsylvania Regeneration Study tell us about oak/hickory forests under stress?

    Science.gov (United States)

    William H. McWilliams; James A. Westfall; Patrick H. Brose; Shawn L. Lehman; Randall S. Morin; Todd E. Ristau; Alejandro A. Royo; Susan L. Stout

    2017-01-01

    The Pennsylvania Regeneration Study was initiated in 1989 because of concerns about a long history of stress on oak/hickory (Quercus/Carya) forests from herbivory and other factors. The study, which addresses the need for landscape-level information about regeneration quality and abundance, comprises a suite of regeneration indicator measurements...

  12. Growth and mortality of pin oak and pecan reforestation in a constructed wetland: analysis with management implications

    Science.gov (United States)

    D.E. Henderson; P. Botch; J. Cussimanio; D. Ryan; J. Kabrick; D. Dey

    2009-01-01

    Pin oak (Quercus palustris Muenchh.) and pecan (Carya illinoensis (Wangenh.) K. Koch) trees were planted on reforestation plots at Four Rivers Conservation Area in west-central Missouri. The study was conducted to determine survival and growth rates of the two species under different production methods and environmental variables....

  13. Molecular and morphological characterization of Xiphinema chambersi population from live oak in Jekyll Island, Georgia, with comments on morphometric variations

    Science.gov (United States)

    Zafar A. Handoo; Lynn K. Carta; Andrea M. Skantar; Sergei A. Subbotin; Stephen Fraedrich

    2016-01-01

    A population of Xiphinema chambersi from the root zone around live oak (Quercus virginiana Mill.) trees on Jekyll Island, GA, is described using both morphological and molecular tools and compared with descriptions of type specimens. Initially, because of a few morphological differences, this nematode was thought to represent an undescribed species. However, on further...

  14. Decay detection in red oak trees using a combination of visual inspection, acoustic testing, and resistance microdrilling

    Science.gov (United States)

    Xiping Wang; R. Bruce Allison

    2008-01-01

    Arborists are often challenged to identify internal structural defects hidden from view within tree trunks. This article reports the results of a study using a trunk inspection protocol combining visual observation, single-path stress wave testing, acoustic tomography, and resistance microdrilling to detect internal defects. Two century-old red oak (Quercus rubra)...

  15. Autonomous third-order duffing-holmes type chaotic oscillator

    DEFF Research Database (Denmark)

    Lindberg, Erik; Tamaseviciute, E; Mykolaitis, G

    2009-01-01

    A novel Duffing-Holmes type autonomous chaotic oscillator is described. In comparison with the well-known nonautonomous Duffing-Holmes circuit it lacks the external periodic drive, but includes two extra linear feedback subcircuits, namely a direct positive feedback loop, and an inertial negative...... feedback loop. In contrast to many other autonomous chaotic oscillators, including linear unstable resonators and nonlinear damping loops, the novel circuit is based on nonlinear resonator and linear damping loop in the negative feedback. SPICE simulation and hardware experimental investigations...... are presented. The Lyapunov exponents calculated from the rate equations confirm dynamical nature of chaotic oscillations....

  16. A. Conan Doyle, Sherlock Holmes, and murder by tropical infection.

    Science.gov (United States)

    Ehrenkranz, N J

    1987-01-01

    The scientific insights with which A. Conan Doyle endowed his creation, the master detective Sherlock Holmes, continue to attract scholarly interest. Indeed, the clinical and/or scientific aspects of Doyle's fiction hold appeal for those interested in the epidemiology of tropical infectious diseases. The origins and routes of transmission of tropical infections were subjects of fruitful investigation in the latter half of the nineteenth century. In "The Adventure of the Dying Detective," Sherlock Holmes investigates a murder that he suspects to have resulted from a fatal Asiatic disease associated with a short incubation period: the indications point to primary septicemic plague as the murder weapon.

  17. A medical perspective on the adventures of Sherlock Holmes.

    Science.gov (United States)

    Reed, J

    2001-12-01

    The adventures of Sherlock Holmes, although primarily famous as stories of detection of crime, offer a considerable amount to interest the medical reader. There are many medical references in the stories, and the influence of Conan Doyle's medical background is clearly seen in the main characters. Aspects of the stories also reflect Conan Doyle's medical career, and also something of his attitude towards the profession. From Holmes's sayings and accounts of his methods, parallels can be drawn between Holmesian deduction and the diagnostic process. It is concluded, however, that deduction cannot be used as a direct paradigm since medical problems are rarely soluble through a process of logic alone.

  18. Reference gene selection for quantitative real-time PCR normalization in Quercus suber.

    Science.gov (United States)

    Marum, Liliana; Miguel, Andreia; Ricardo, Cândido P; Miguel, Célia

    2012-01-01

    The use of reverse transcription quantitative PCR technology to assess gene expression levels requires an accurate normalization of data in order to avoid misinterpretation of experimental results and erroneous analyses. Despite being the focus of several transcriptomics projects, oaks, and particularly cork oak (Quercus suber), have not been investigated regarding the identification of reference genes suitable for the normalization of real-time quantitative PCR data. In this study, ten candidate reference genes (Act, CACs, EF-1α, GAPDH, His3, PsaH, Sand, PP2A, ß-Tub and Ubq) were evaluated to determine the most stable internal reference for quantitative PCR normalization in cork oak. The transcript abundance of these genes was analysed in several tissues of cork oak, including leaves, reproduction cork, and periderm from branches at different developmental stages (1-, 2-, and 3-year old) or collected in different dates (active growth period versus dormancy). The three statistical methods (geNorm, NormFinder, and CV method) used in the evaluation of the most suitable combination of reference genes identified Act and CACs as the most stable candidates when all the samples were analysed together, while ß-Tub and PsaH showed the lowest expression stability. However, when different tissues, developmental stages, and collection dates were analysed separately, the reference genes exhibited some variation in their expression levels. In this study, and for the first time, we have identified and validated reference genes in cork oak that can be used for quantification of target gene expression in different tissues and experimental conditions and will be useful as a starting point for gene expression studies in other oaks.

  19. Reference gene selection for quantitative real-time PCR normalization in Quercus suber.

    Directory of Open Access Journals (Sweden)

    Liliana Marum

    Full Text Available The use of reverse transcription quantitative PCR technology to assess gene expression levels requires an accurate normalization of data in order to avoid misinterpretation of experimental results and erroneous analyses. Despite being the focus of several transcriptomics projects, oaks, and particularly cork oak (Quercus suber, have not been investigated regarding the identification of reference genes suitable for the normalization of real-time quantitative PCR data. In this study, ten candidate reference genes (Act, CACs, EF-1α, GAPDH, His3, PsaH, Sand, PP2A, ß-Tub and Ubq were evaluated to determine the most stable internal reference for quantitative PCR normalization in cork oak. The transcript abundance of these genes was analysed in several tissues of cork oak, including leaves, reproduction cork, and periderm from branches at different developmental stages (1-, 2-, and 3-year old or collected in different dates (active growth period versus dormancy. The three statistical methods (geNorm, NormFinder, and CV method used in the evaluation of the most suitable combination of reference genes identified Act and CACs as the most stable candidates when all the samples were analysed together, while ß-Tub and PsaH showed the lowest expression stability. However, when different tissues, developmental stages, and collection dates were analysed separately, the reference genes exhibited some variation in their expression levels. In this study, and for the first time, we have identified and validated reference genes in cork oak that can be used for quantification of target gene expression in different tissues and experimental conditions and will be useful as a starting point for gene expression studies in other oaks.

  20. Estudio cariológico de Quercus humboldtti Bonpl Caryological study of Quercus humboldtii Bonpl

    Directory of Open Access Journals (Sweden)

    Alvarado de Coral Cecilia

    1989-12-01

    Full Text Available Se comprobó que la especie del roble Ouercus humboldtii Bonpl. tiene 2 n= 24 cromosomas, al igual que la mayoría de las especies estudiadas de Quercus. Utilizando pretratamiento y tinción con orceina lactopropiónica fue posible obtener el cariotipo e ideograma.Using lactopropionic orceine for a previus tintion we obtained the Caryotype and ideogram of Quercus humboldtii Bonpl. and we observed that it has 2 n = 24 chromosomes as most studied species of Quercus do.

  1. Temperature stress effects in Quercus suber leaf metabolism.

    Science.gov (United States)

    Chaves, Inês; Passarinho, José António P; Capitão, Cláudio; Chaves, Maria Manuela; Fevereiro, Pedro; Ricardo, Cândido P P

    2011-10-15

    Based on projections that climate changes are will intensify in the near future, it is important to understand how plants respond to climate. Consequently, we have been studying the effect of contrasting temperatures on leaf metabolism of Quercus suber, an important Mediterranean oak. Potted plants were grown under controlled conditions for 53 days at 28°C or 10°C. The accumulation of major soluble metabolites was analyzed by NMR. The relative levels of transcripts of genes encoding key enzymes of the shikimate and phenylpropanoid pathway (CS, PAL, CAD and ChS) were examined by means of quantitative, real-time RT-PCR. At 10°C, in the pre-existing leaves, the concentrations of sucrose, quercitol and catechin were higher, as were PAL and ChS transcripts. At 28°C, however, it was the concentration of quinic acid that was higher, as were the concentrations of CS and CAD transcripts. We conclude that contrasting temperatures greatly influence Q. suber metabolism and that a deeper analysis of the effects of more extreme temperatures is needed to understand the possible effects of temperature changes on Q. suber metabolism and physiology.

  2. Presence of env-like sequences in Quercus suber retrotransposons.

    Science.gov (United States)

    Carvalho, M; Ribeiro, T; Viegas, W; Morais-Cecilio, L; Rocheta, M

    2010-01-01

    The main difference between LTR retrotransposons and retroviruses is the presence of the envelope (env) gene in the latter, downstream of the pol gene. The env gene is involved in their infectious capacity. Here we report the presence of env-like sequences in the genome of Quercus suber (cork oak), one of the most economically important Portuguese species. These gene sequences were isolated through DNA amplification between RNaseH conserved motifs and 3' LTR, based on the structure of copia retrotransposons. Phylogenetic analysis revealed that almost all the clones isolated are clustered with Cyclops-2, a Ty3-gypsy element identified in Pisum sativum, except one clustered with gypsy and copia retroelements found in different species. This suggests the existence of a potential ancestral sequence of the env gene, prior to the separation of Ty3-gypsy and Ty1-copia retrotransposons. Additionally, the isolated env-like sequences showed 26-39% of homology with env-like sequences characterized in viruses. The origin of env-like sequences in retrotransposons from host plant taxa is discussed.

  3. Sherlock Holmes Meets Othello: A MDS Analysis of Literary Characters.

    Science.gov (United States)

    Russell, G. W.; Lambert, W. B.

    1980-01-01

    Changes in college freshmen's perceptual organization of characters from "Othello" after three weeks of study and lecture were assessed using multidimensional scaling procedures. Sherlock Holmes experts also provided dissimilarity ratings of Conan Doyle's characters. Discussion centers on the extent to which the lectures on "Othello" effected…

  4. Sherlock Holmes Meets Othello: A MDS Analysis of Literary Characters.

    Science.gov (United States)

    Russell, G. W.; Lambert, W. B.

    1980-01-01

    Changes in college freshmen's perceptual organization of characters from "Othello" after three weeks of study and lecture were assessed using multidimensional scaling procedures. Sherlock Holmes experts also provided dissimilarity ratings of Conan Doyle's characters. Discussion centers on the extent to which the lectures on…

  5. Playing "Sherlock Holmes": Enhancing Students' Understanding of Prejudice and Stereotyping.

    Science.gov (United States)

    Junn, Ellen N.; Grier, Leslie K.; Behrens, Debra P.

    2001-01-01

    Describes an experiential classroom exercise that was designed to help students understand stereotyping and prejudice. The instructor read behavioral and psychological descriptions, asked students to imagine they were Sherlock Holmes, and identify classmates to whom the descriptions might apply. States that students of color reported more benefits…

  6. Cardiovascular disease in the Adventures of Sherlock Holmes.

    Science.gov (United States)

    Ramanan, S V

    2001-03-12

    The Adventures of Sherlock Holmes by Sir Arthur Conan Doyle contains many incidents of medical interest. While disorders of the cardiovascular system do not play an important role in these tales, there are, nevertheless, some illnesses that invite speculation. Eleven such incidents are reviewed and discussed in light of the times in which they occurred and in light of current medical knowledge.

  7. Playing "Sherlock Holmes": Enhancing Students' Understanding of Prejudice and Stereotyping.

    Science.gov (United States)

    Junn, Ellen N.; Grier, Leslie K.; Behrens, Debra P.

    2001-01-01

    Describes an experiential classroom exercise that was designed to help students understand stereotyping and prejudice. The instructor read behavioral and psychological descriptions, asked students to imagine they were Sherlock Holmes, and identify classmates to whom the descriptions might apply. States that students of color reported more benefits…

  8. Sherlock Holmes and tropical medicine: a centennial appraisal.

    Science.gov (United States)

    Sodeman, W A

    1994-01-01

    Sir Arthur Conan Doyle incorporated an unidentified tropical disease as a murder weapon in the Sherlock Holmes story, "The Dying Detective," written in 1913. Documentary and circumstantial evidence suggests that the disease mentioned was melioidosis. The description of the newly identified disease occurred shortly before Doyle's death. Doyle's other works at the time reflect a consistent interest in tropical disease.

  9. Sherlock Holmes Meets Othello: A MDS Analysis of Literary Characters.

    Science.gov (United States)

    Russell, G. W.; Lambert, W. B.

    1980-01-01

    Changes in college freshmen's perceptual organization of characters from "Othello" after three weeks of study and lecture were assessed using multidimensional scaling procedures. Sherlock Holmes experts also provided dissimilarity ratings of Conan Doyle's characters. Discussion centers on the extent to which the lectures on…

  10. Our Magnetic Planet (Arthur Holmes Medal Lecture)

    Science.gov (United States)

    Laj, Carlo

    2015-04-01

    It is a great honour to receive the Arthur Holmes Medal, certainly the highest scientific award of my life. My first thoughts and deep gratitude are with the people who have contributed to me being here today, from my PhD mentors, Pierre Berge and Pierre Pério, later Jacques Labeyrie, my colleagues and students and last, but not least, the members of the Committee on Education of EGU, with whom I have shared over 10 years of a wonderful educational activity. In this presentation, among the various scientific arguments in which I have been involved, I will recall only those mentioned in my letter of nomination to the Holmes Medal, trying to replace them in what was known at the time. After a PhD in Solid State Physics, working in a laboratory of the Commissariat à l'Énergie Atomique, I obtained a post doctoral research position for the the study of liquid binary critical fluids, and worked on this topics for 5 years. I then joined the Centre des Faibles Radioactivités, a CNRS-CEA Institute dedicated to the study of geological-environmental phenomena. My first task there has been to develop a paleomagnetic laboratory, dedicated to the study of Earth Sciences, through the study of the magnetic properties of sediments and igneous rocks. From there on, my entire scientific activity has been devoted to the study of our "Magnetic Planet". My first project in Geophysics dealt with the geodynamical evolution of the Aegean Arc. At the time, only a few paleomagnetic studies existed in the Mediterranean realm, and none in the Aegean region. Moreover all of them dealt with rather old geological formations, so that almost nothing was known about the recent post-cretaceous evolution. The originality of our study was to start from the most recent to the older formations, in order to precisely describe "retro-tectonically" the different phases of rotational deformation. This intensive study (over 700 sampling sites, over 10,000 samples spread over continental Greece, the Aegean

  11. Obituary: Elizabeth Katherine Holmes, 1973-2004

    Science.gov (United States)

    Beichman, Charles Arnold

    2004-12-01

    Elizabeth (Beth) K. Holmes died suddenly in Pasadena on March 23, 2004, from the unexpected effects of a long-standing heart condition. She was 30 years old. At the moment of her passing, she was at her computer comparing her theoretical models on the effects of planets on the distribution of zodiacal dust with some of the first observations from the Spitzer Space Telescope. Born on June 24, 1973, in New York City, Beth was the only child of James and Barbara Holmes, who were respectively, a financial manager and a nurse and social worker. Undeterred by numerous treatments and operations to correct a congenital heart condition, Beth developed an interest in math and physics leading to her graduation from MIT in 1995 with a bachelor's degree in Physics. She entered the University of Florida shortly afterwards to begin her PhD studies under the direction of Stanley Dermott. Beth was particularly interested in the dynamics of interplanetary dust, and initially worked on secular perturbations of the zodiacal cloud: how the planets impose warping of the cloud, and how they can force the center of the cloud to be offset from the Sun. Despite the fact that Beth was primarily a theorist, she was keen to include some observing experience in her PhD education. She recently completed an observing program with Harold Butner at the Steward and Palomar Observatories looking for submillimeter and mid-infrared emission around nearby main-sequence stars - a signpost of planetary formation. The results were published last year in the Astronomical Journal. Beth's PhD thesis work, some results of which were recently published in the Astrophysical Journal, focused on dust originating in the Kuiper belt and how some of this dust is expected to be spatially structured due to resonant interactions with Neptune. This phenomenon may be quite common in other planetary systems, with recent images of Epsilon Eridani perhaps providing a prime example of a Kuiper disk analog. After graduating

  12. Soil properties linked to Phytophthora cinnamomi presence and oak decline in Iberian dehesas

    Science.gov (United States)

    Moreno, G.; Vivas, M.; Pérez, A.; Cubera, E.; Madeira, M.; Solla, A.

    2009-04-01

    Dehesas cover about 3,100,000 ha in the Iberian Peninsula, and support an outstanding diversity of wildlife and flora endemisms. These open woodlands provide Spain and Portugal inhabitants with a high-quality food, derived from animal production, sustain rural population, and act as retardants of soil erosion and desertification, which are considered primary environmental concerns in the Mediterranean basin. Dehesas are considered examples of sustainable use, though in the last few decades intensive land use, imposed by a concomitant change in the technological and socio-economic conditions, and common agricultural policies threat their conservation. Soil compaction and erosion, oak regeneration failure, dieback of old-ageing stands, and loose of biodiversity are some of the most common threats. At the same time, a severe decline of Quercus ilex (Holm oak) has been reported since the 1990s in the southern Iberian Peninsula, and more recently in France, Italy, and Morocco. In the Iberian Peninsula, the decline has been mostly observed in dehesas, where a combination of factors, possibly acting in synergy, have been put forward to explain the disease. Severe drought episodes, flooding, and rapid fluctuations in soil water content have been reported as predisposing factors favoring tree invasion by bark borer insects and/or pathogenic fungi. It is mostly ignored to what extent decline is a natural or a man-induced process, and if it is associated to either basic, management-related soil properties, or both. To bring insight to this problem, extensive and integrative comparisons of some soil properties related to hydromorphism were initiated, comprising pairs of adjacent non-symptomatic and symptomatic Q. ilex trees. In 2008, 48 dehesa stands from western Spain (Cáceres), half of them located along stream banks and the other half located in slopes, were intensively studied. In each stand, soil and root samples were taken under 3 non-symptomatic (healthy) and 3

  13. Dimeric and trimeric hydrolyzable tannins from Quercus coccifera and Quercus suber.

    Science.gov (United States)

    Ito, Hideyuki; Yamaguchi, Koji; Kim, Tae-Hoon; Khennouf, Seddik; Gharzouli, Kamel; Yoshida, Takashi

    2002-03-01

    Three new hydrolyzable tannins, cocciferins D(1) (1), D(2) (2), and T(1) (4), were isolated from the leaves of Quercus coccifera. Cocciferin D(2) (2) and two additional new tannins, cocciferins D(3) (3) and T(2) (5), were also obtained from the leaves of Quercus suber. Their oligomeric structures were elucidated on the basis of spectroscopic methods and chemical evidence. Compounds 2, 3, and 5 were rare oligomers possessing glucose cores with both open-chain and pyranose forms.

  14. Quercus petraea in België

    NARCIS (Netherlands)

    Rompaey, van E.

    1957-01-01

    Naar aanleiding van het artikel over Quercus petraea in het Corr. bl. no. 4 zend ik u hierbij een kopie van de Belgische verspreidingskaart, omdat daar m.i. wel een en ander uit af te leiden is, dat ook Nederland aanbelangt: 1. Bij bet massale verspreidingsgebied ten Z. van de lijn Samber-Maas (de l

  15. Carbon Stock Potential of Oak and Pine Forests in Garhwal Region in Indian Central Himalayas

    Directory of Open Access Journals (Sweden)

    Nanda Nautiyal

    2013-05-01

    Full Text Available Oak (Quercus leucotichophora and pine (Pinus roxburghii are the two most dominant forest types occurring in Indian Central Himalayas. CO2 mitigation potential of these two forest types was observed in the present study. Carbon stock densities for AGTB, BB, LHG, DWS, AGSB and SOC were estimated and higher values were recorded in oak forest stands. Total carbon density estimated was 2420.54 Mg/ha for oak forest of Gopeshwar and 986.93 Mg/ha for pine forest of Nandprayag. CO2 mitigation potential of oak forest of Gopeshwar was recorded to be 8,713.94 CO2e and of pine forests 3552.95 CO2e.

  16. Oaks were the historical foundation genus of the east-central United States

    Science.gov (United States)

    Hanberry, Brice B.; Nowacki, Gregory J.

    2016-08-01

    Foundation tree species are dominant and define ecosystems. Because of the historical importance of oaks (Quercus) in east-central United States, it was unlikely that oak associates, such as pines (Pinus), hickories (Carya) and chestnut (Castanea), rose to this status. We used 46 historical tree studies or databases (ca. 1620-1900) covering 28 states, 1.7 million trees, and 50% of the area of the eastern United States to examine importance of oaks compared to pines, hickories, and chestnuts. Oak was the most abundant genus, ranging from 40% to 70% of total tree composition at the ecological province scale and generally increasing in dominance from east to west across this area. Pines, hickories, and chestnuts were co-dominant (ratio of oak composition to other genera of <2) in no more than five of 70 ecological subsections and two of 20 ecological sections in east-central United States, and thus by definition, were not foundational. Although other genera may be called foundational because of localized abundance or perceptions resulting from inherited viewpoints, they decline from consideration when compared to overwhelming oak abundance across this spatial extent. The open structure and high-light conditions of oak ecosystems uniquely supported species-rich understories. Loss of oak as a foundation genus has occurred with loss of open forest ecosystems at landscape scales.

  17. Oak conservation and restoration on private forestlands: negotiating a social-ecological landscape.

    Science.gov (United States)

    Knoot, Tricia G; Schulte, Lisa A; Rickenbach, Mark

    2010-01-01

    In the midwestern United States, oak (Quercus spp.) forests are considered critical habitat for conserving biodiversity and are a declining resource. Ecological conditions, such as deer herbivory and competition from more mesic broad-leaved deciduous species, have been linked to poor oak regeneration. In the Midwest, where up to 90% of forestland is privately owned, a greater understanding of social dimensions of oak regeneration success is especially critical to designing effective restoration strategies. We sought to determine factors that serve as direct and indirect constraints to oak restoration and identify policy mechanisms that could improve the likelihood for restoration success. We conducted in-depth qualitative interviews with 32 natural resource professionals working in the Midwest Driftless Area. We found that most professionals anticipate that oak will remain only a component of the future forest. Furthermore, they identified the general unwillingness of landowners to adopt oak restoration practices as a primary driving force of regional forest change. The professionals pointed to interdependent ecological and social factors, occurring at various scales (e.g., economic cost of management, deer herbivory, and exurban residential development) as influencing landowner oak restoration decisions. Professionals emphasized the importance of government cost-share programs and long-term personal relationships to securing landowner acceptance of oak restoration practices. However, given finite societal resources, ecologically- and socially-targeted approaches were viewed as potential ways to optimize regional success.

  18. Metabarcoding of Bacteria Associated with the Acute Oak Decline Syndrome in England

    Directory of Open Access Journals (Sweden)

    Melanie Sapp

    2016-04-01

    Full Text Available Outbreaks of acute oak decline (AOD have been documented in England from 2006. Both species of native oaks (Quercus robur and Quercus petraea are affected. To complement isolation efforts for identification of putative causative biotic agents and increase our understanding of bacteria associated with oak tissue, five sites in England were chosen for this study. Samples of outer bark, inner bark, sapwood and heartwood were taken from healthy oak and trees with symptoms at varying stages of the syndrome. Furthermore, larval galleries attributed to infestation with Agrilus biguttatus were included. After DNA extraction and amplification of the V3–V5 fragment of the bacterial 16S rRNA genes by pyrosequencing, the dataset was analyzed to identify patterns in bacterial communities in oak tissue samples with and without AOD symptoms at each site. The composition of bacterial communities differed greatly according to the site from which the samples were obtained. Within each site, the composition of the bacteria associated with symptomatic tissue varied between advanced stages of the syndrome and healthy tissue. Key players in healthy and symptomatic tissue were identified and included members of the Gammaproteobacteria related to Pseudomonas sp. or Brenneria goodwinii and members of the Firmicutes.

  19. Fragmentation patterns of evergreen oak woodlands in Southwestern Iberia: identifying key spatial indicators.

    Science.gov (United States)

    Costa, Augusta; Madeira, Manuel; Lima Santos, José; Plieninger, Tobias; Seixas, Júlia

    2014-01-15

    Mediterranean evergreen oak woodlands (composed of Quercus suber L. and Quercus rotundifolia Lam.) are becoming increasingly fragmented in the human-modified landscapes of Southwestern Portugal and Spain. Previous studies have largely neglected to assess the spatial changes of oak woodlands in relation to their surrounding landscape matrix, and to characterize and quantify woodland boundaries and edges. The present study aims to fill this gap by analyzing fragmentation patterns of oak woodlands over a 50-year period (1958-2007) in three landscapes. Using archived aerial imagery from 1958, 1995 and 2007, for two consecutive periods (1958-1995 and 1995-2007), we calculated a set of landscape metrics to compare woodland fragmentation over time. Our results indicated a continuous woodland fragmentation characterized by their edge dynamics. From 1958 to 2007, the replacement of open farmland by shrubland and by new afforestation areas in the oak woodland landscape surrounding matrix, led to the highest values for edge contrast length trends of 5.0 and 12.3, respectively. Linear discriminant analysis was performed to delineate fragmented woodland structures and identify metric variables that characterize woodland spatial configuration. The edge contrast length with open farmland showed a strong correlation with F1 (correlations ranging between 0.55 and 0.98) and may be used as a proxy for oak woodland mixedness in landscape matrix. The edge dynamics of oak woodlands may result in different patterns of oak recruitment and therefore, its study may be helpful in highlighting future baselines for the sustainable management of oak woodlands.

  20. Acorn fall and weeviling in a northern red oak seedling orchard

    Science.gov (United States)

    Daniel R. Miller; Scott E. Schlarbaum

    2005-01-01

    In 2000, we determined levels of damage by acorn weevils (Curculio spp.) and patterns of acorn fall in a northern red oak (Quercus rubra L.) seedling orchard in eastern Tennessee. The mean (±SE) production of acorns among 43 selected trees was 5,930 ± 586 acorns per tree with a maximum production level of 16,969 acorns for one tree...

  1. Performance of northern red oak seedlings across a pH gradient

    Science.gov (United States)

    Anthony S. Davis; Douglass F. Jacobs

    2005-01-01

    Northern red oak (Quercus rubra L.) seedlings were grown from acorns in 4-gallon containers in a greenhouse. Growing medium was amended to a pH of 3.50, 4.25, 5.00, and 5.75 using tri-weekly applications of aluminum sulfate. In addition, seedlings were subjected to either: (1) addition of a 16- to 18-month controlled release fertilizer (CRF), (2)...

  2. Reciprocal Transformations of Two Camassa-Holm Type Equations

    Science.gov (United States)

    Li, Hong-Min; Li, Yu-Qi; Chen, Yong

    2015-12-01

    The relation between the Camassa-Holm equation and the Olver-Rosenau-Qiao equation is obtained, and we connect a new Camassa-Holm type equation proposed by Qiao etc. with the first negative flow of the KdV hierarchy by a reciprocal transformation. Supported by the Global Change Research Program of China under Grant No. 2015CB953904, National Natural Science Foundation of China under Grant Nos.11275072, 11375090 and 11435005, Research Fund for the Doctoral Program of Higher Education of China (No. 20120076110024), The Network Information Physics Calculation of basic research innovation research group of China under Grant No. 61321064, Shanghai Collaborative Innovation Center of Trustworthy Software for Internet of Things under Grant No. ZF1213, Shanghai Minhang District talents of high level scientific research project.

  3. Isoprenoid emission of oak species typical for the Mediterranean area: Source strength and controlling variables

    Science.gov (United States)

    Steinbrecher, Rainer; Hauff, Karin; Rabong, Richard; Steinbrecher, Jutta

    Measurements of isoprenoid emission on five Mediterranean oak species in the field revealed that Quercus frainetto, Quercus petraea and Quercus pubescens are strong emitters of isoprene. In contrast Quercus cerris and Quercus suber emitted no significant amounts of isoprene and monoterpenes. For Q. pubenscens and Q. frainetto median emission factors of 16.68 nmol m -2 s -1 (86.06 μg g -1 dw h -1) and 30.72 nmol m -2 s -1 (133.95 μg g -1 dw h -1 were calculated, respectively. The 25 to 75 percentiles span of the emission factor data sets ranged from - 53% to + 56% of the median values. Light and temperature are the main controlling factors for isoprene emission. The influence of other environmental and plant physiological parameters on the isoprene emission is discussed. The "Guenther" emission algorithm is able to predict the daily maximum of the isoprene emission within the plant specific uncertainty range. However, the morning increase and the afternoon drop in the isoprene emission is not well parameterized. On the basis of process oriented models for the synthesis of isoprene in plants, a further reduction in the uncertainty may be achieved resulting in a more reliable prediction of short-time variation in isoprene emission.

  4. Impacts of elevated atmospheric CO2 on litter quality, litter decomposability and nitrogen turnover rate of two oak species in a Mediterranean forest ecosystem

    NARCIS (Netherlands)

    Fayez Raiesi Gahrooee,

    1998-01-01

    Elevated CO2 may affect litter quality of plants, and subsequently C and N cycling in terrestrial ecosystems, but changes in litter quality associated with elevated CO2 are poorly known. Abscised leaf litter of two oak species (Quercus cerris L., and Q. pubescens Willd.) exposed to long-term elevate

  5. Stand-level growth and yield component models for red oak-sweetgum forests on Mid-South minor stream bottoms

    Science.gov (United States)

    Emily B. Schultz; J. Clint Iles; Thomas G. Matney; Andrew W. Ezell; James S. Meadows; Theodor D. Leininger; al. et.

    2010-01-01

    Greater emphasis is being placed on Southern bottomland hardwood management, but relatively few growth and yield prediction systems exist that are based on sufficient measurements. We present the aggregate stand-level expected yield and structural component equations for a red oak (Quercus section Lobatae)-sweetgum (Liquidambar styraciflua L.) growth and yield model....

  6. Use of Nested and Real-Time PCR for the Detection of Ceratocystis fagacearum in the Sapwood of Diseased Oak Species in Minnesota

    Science.gov (United States)

    A. Yang; J. Juzwik

    2017-01-01

    Oak wilt caused by Ceratocystis fagacearum is a significant disease of Quercus spp. in the eastern United States. Early and accurate detection of the pathogen is particularly important when disease control is planned. Nested and real-time polymerase chain reaction (PCR) methods utilizing fungal DNA extracted from sapwood drill...

  7. Molecular and morphological characterization of Xiphinema chambersi population from live oak in Jekyll Island, Georgia, with comments on morphometric variations

    Science.gov (United States)

    Zafar A Handoo; Lynn K. Carta; Andrea M. Skantar; Sergei A. Subbotin; Stephen W. Fraedrich

    2016-01-01

    A population of Xiphinema chambersi from the root zone around live oak (Quercus virginiana Mill.) trees on Jekyll Island, GA, is described using both morphological and molecular tools and compared with descriptions of type specimens. Initially, because of a few morphological differences, this nematode was thought to represent...

  8. An evaluation of seven methods for controlling mountain laurel thickets in the mixed-oak forests of the central Appalachian Mountains, USA

    Science.gov (United States)

    Patrick H. Brose

    2017-01-01

    In the Appalachian Mountains of eastern North America, mountain laurel (Kalmia latifolia) thickets in mixed-oak (Quercus spp.) stands can lead to hazardous fuel situations, forest regeneration problems, and possible forest health concerns. Therefore, land managers need techniques to control mountain laurel thickets and limit...

  9. Stability of peakons for the generalized Camassa-Holm equation

    Directory of Open Access Journals (Sweden)

    Orlando Lopes

    2003-01-01

    Full Text Available We study the existence of minimizers for a constrained variational problems in $H^1(mathbb{R}$. These minimizers are stable waves solutions for the Generalized Camassa-Holm equation, and their derivative may have a singularity (in which case the travelling wave is called a peakon. The existence result is based on a method developed by the same author in a previous work. By giving examples, we show how our method works.

  10. Initial data problems for the two-component Camassa-Holm system

    Directory of Open Access Journals (Sweden)

    Xiaohuan Wang

    2014-06-01

    Full Text Available This article concerns the study of some properties of the two-component Camassa-Holm system. By constructing two sequences of solutions of the two-component Camassa-Holm system, we prove that the solution map of the Cauchy problem of the two-component Camassa-Holm system is not uniformly continuous in $H^s(\\mathbb{R}$, $s>5/2$.

  11. Climate change impact on a mixed lowland oak stand in Serbia

    Directory of Open Access Journals (Sweden)

    Dejan Stojanović

    2015-12-01

    Full Text Available Climatic changes and bad environmental conditions may lead to forests vitality loss and even mortality. This is the reason why increased sanitary felling operations were performed in mixed oak forests in northern Serbia in 2013 in order to solve the severe dieback which affected some Pedunculate oak (Quercus robur L. and Turkey oak (Quercus cerris L. stands, after the very dry years 2011 and 2012.Dendrochronological techniques were applied to both these oak species collected in a stand, to examine the impact of temperature, precipitation and ground water level on forest growth and investigate the potential causes of the dieback.Differences in tree-ring patterns between surviving and dead trees were not significant according to t-value (from 5.68 to 14.20 and Gleichläufigkeit coefficient (from 76% to 82%, this meaning no distinctive responses of the two ecologically different oak species. As for radial increment, pedunculate and Turkey oak trees showed a similar response to environmental variables in this mixed stand. The Simple Pearson’s correlation analysis, which was conducted, showed that among three basic environmental variables (the mean monthly air temperature, the monthly sum of precipitation and the mean monthly water level, proxy of ground water level, the water level of Danube river in May and the temperature in April were statistically related to the growth of the four tree groups: (i pedunculate oak vital, (ii pedunculate oak dead, (iii Turkey oak vital and (iv Turkey oak dead trees, for the period 1961-2010 (p<0.05, n=60. Similar phenomena had already been observed in the Sava River basin for the growth of pure pedunculate oak forests. The long-term decline of the Danube River water level may be related to climate variations and to the changes of water management, river bed, as well as land-use. Together with the increase of temperature, this decline of the water level, and its potential unavailability in the soil, represents a

  12. Darboux transformation and multi-soliton solutions of the Camassa-Holm equation and modified Camassa-Holm equation

    Science.gov (United States)

    Xia, Baoqiang; Zhou, Ruguang; Qiao, Zhijun

    2016-10-01

    In this paper, we propose a new approach to calculate multi-soliton solutions of Camassa-Holm (CH) equation and modified Camassa-Holm (MCH) equation with the aid of Darboux transformation (DT). The new approach simplifies the approach presented by Li and Zhang [Proc. R. Soc. London, Ser. A 460, 2617-2627 (2004)]. We first map the CH and MCH equation to a negative order KdV (NKdV) equation by a reciprocal transformation. Then we proceed to apply the DT to solve the NKdV equation in the usual way. Finally we invert the reciprocal transformation to recover the solutions of the CH equation and MCH equation.

  13. Large-scale patterns of Quercus ilex, Quercus suber, and Quercus pyrenaica regeneration in central-western Spain

    DEFF Research Database (Denmark)

    Plieninger, Tobias; Rolo, Víctor; Moreno, Gerardo

    2010-01-01

    ; that there are differences in the abundance of regeneration between three oak species; that oak regeneration is governed mainly by forest management and structure; and that shrubs act as important physical protectors of seedlings and saplings. We analyzed whether densities of oak seedlings and saplings in several size...... classes were related to stand-structure, understory, and physiographic variables potentially affecting regeneration. Data collected at a regional level (1 km × 1 km grid) by the Spanish Forest Inventory were evaluated from 2,816 plots. Results revealed that regeneration failure was common for all size....... Regeneration was positively correlated with tree cover and density, especially of small and medium-sized trees, and negatively correlated with the presence of large trees, indicating that regeneration failure is mostly associated with more open, uniform, and/or aged woodlands. Regeneration densities of Q. ilex...

  14. Identificação do carbamato de etila durante o armazenamento da cachaça em tonel de carvalho (quercus sp e recipiente de vidro

    Directory of Open Access Journals (Sweden)

    Jeancarlo Pereira dos Anjos

    2011-01-01

    Full Text Available The objective of the present study was the identification and quantification of ethyl carbamate (EC, by HPLC-FLD, after different periods of storage in an oak (Quercus sp barrel and a glass vessel. The concentration of EC in the cachaça samples varied from oak barrel, and oak barrel and the glass vessel resulted in a significant increase in the concentration of this contaminant.

  15. Photosynthesis of Quercus suber is affected by atmospheric NH3 generated by multifunctional agrosystems.

    Science.gov (United States)

    Pintó-Marijuan, Marta; Da Silva, Anabela Bernardes; Flexas, Jaume; Dias, Teresa; Zarrouk, Olfa; Martins-Loução, Maria Amélia; Chaves, Maria Manuela; Cruz, Cristina

    2013-12-01

    Montados are evergreen oak woodlands dominated by Quercus species, which are considered to be key to biodiversity conservation and ecosystem services. This ecosystem is often used for cattle breeding in most regions of the Iberian Peninsula, which causes plants to receive extra nitrogen as ammonia (NH(3)) through the atmosphere. The effect of this atmospheric NH(3) (NH(3atm)) on ecosystems is still under discussion. This study aimed to evaluate the effects of an NH(3atm) concentration gradient downwind of a cattle barn in a Montado area. Leaves from the selected Quercus suber L. trees along the gradient showed a clear influence of the NH(3) on δ(13)C, as a consequence of a strong limitation on the photosynthetic machinery by a reduction of both stomatal and mesophyll conductance. A detailed study of the impact of NH(3atm) on the photosynthetic performance of Q. suber trees is presented, and new mechanisms by which NH(3) affects photosynthesis at the leaf level are suggested.

  16. The State of the System and Steps Toward Resilience of Disturbance-dependent Oak Forests

    Directory of Open Access Journals (Sweden)

    Tricia G. Knoot

    2010-12-01

    Full Text Available Current ecological, economic, and social conditions present unique challenges to natural resource managers seeking to maintain the resilience of disturbance-dependent ecosystems, such as oak (Quercus spp. forests. Oak-dominated ecosystems throughout the U.S. have historically been perpetuated through periodic disturbance, such as fire, but more recently show decline given shifting disturbance regimes associated with human land management decisions. We characterized the state of the social-ecological oak forest ecosystem in the midwestern U.S. through the perspectives of 32 natural resource professionals. Data from interviews with these change agents provided an integrative understanding of key system components, cross-scale interactions, dependencies, and feedbacks. Foremost, private landowner management decisions figured prominently in influencing oak regeneration success and were directly and indirectly shaped by a suite of interdependent ecological, e.g., deer herbivory, invasive shrub occurrence; economic, e.g., the cost of oak regeneration practices, the stumpage value of maple as compared to oak; and social forces, e.g., forestland parcelization, and personal relationships. Interviewees envisioned, and often preferred, a decline in oak dominance throughout the region, pointing to issues related to general landowner unwillingness to restore oak, the current trajectory of forest change, the threat of forest loss due to parcelization and housing development, and a combination of ecological and social factors that decrease the economic feasibility of restoration efforts. However, a decline in oak dominance may result in ecological communities that have no compositional equivalent on record and may not offer a desirable endpoint. Increasing social support offers the potential to enhance system capacity to manage for oak.

  17. The negative impact of intentionally introduced Quercus rubra L. on a forest community

    Directory of Open Access Journals (Sweden)

    Beata Woziwoda

    2014-03-01

    Full Text Available Some alien woody species used in commercial forestry become invasive and, as invaders, cause major problems in natural and semi-natural ecosystems. However, the deliberate introduction of aliens can bring unintended negative changes also within areas of their cultivation. This paper presents the effects of the intentional introduction of the North-American Quercus rubra in European mixed Scots pine-Pedunculate oak forests (POFs: Querco roboris-Pinetum (W. Mat. 1981 J. Mat. 1988. Phytosociological data from field research combined with GIS data analysis of the current distribution of Northern Red oak in the studied habitat were used to determine the composition and structure of forest communities in plots with and without Q. rubra participation.  The results show that Q. rubra significantly reduces native species richness and abundance, both in old-growth and in secondary (post-agricultural forests. Not one resident vascular plant benefits from the introduction of Northern Red oak and only a few are able to tolerate its co-occurrence. The natural restocking of all native woody species is also strongly limited by this alien tree.  The introduction of Northern Red oak significantly limits the environmental functions of the POF ecosystem and weakens its economic and social aspects. However, its further cultivation is justified from an economic point of view, as the essential function of the studied forests is commercial timber production, and the introduction of this fast growing alien tree supports the provisioning ecosystem services. A clear description of the level of trade-off between the accepted negative and positive effects of the introduction of Q. rubra on forest ecosystem services requires further interdisciplinary studies.

  18. Quercus suber range dynamics by ecological niche modelling: from the Last Interglacial to present time

    Science.gov (United States)

    Vessella, Federico; Simeone, Marco Cosimo; Schirone, Bartolomeo

    2015-07-01

    Ecological Niche Modelling (ENM) is widely used to depict species potential occurrence according to environmental variables under different climatic scenarios. We tested the ENM approach to infer past range dynamics of cork oak, a keystone species of the Mediterranean Biome, from 130 ka to the present time. Hindcasting implications would deal with a better species risk assessment and conservation management for the future. We modelled present and past occurrence of cork oak using seven ENM algorithms, starting from 63,733 spatially unique presence points at 30 arc-second resolution. Fourteen environmental variables were used and four time slices were considered (Last Interglacial, Last Glacial Maximum, mid-Holocene and present time). A threshold-independent evaluation of the goodness-of-fit of the models was evaluated by means of ROC curve and fossil or historical evidences were used to validate the results. Four weighted average maps depicted the dynamics of area suitability for cork oak in the last 130 ka. The derived species autoecology allowed its long-term occurrence in the Mediterranean without striking range reduction or shifting. Fossil and historical post-processing validation support the modelled past spatial extension and a neglected species presence at Levantine until the recent time. Despite the severe climatic oscillation since the Last Glacial Maximum, cork oak potential distribution area experienced limited range changes, confirming its strong link with the Mediterranean Basin. The ecological amplitude of Quercus suber could be therefore adopted as a reference to trace the Mediterranean bioclimate area. A better knowledge of the past events of Mediterranean vegetation, a wider range of study species and environmental determinants are essential to inform us about its current state, its sensitivity to human impact and the potential responses to future changes.

  19. Impact of stereoide fungi on decomposition of oak wood and possibility of its protection

    Directory of Open Access Journals (Sweden)

    Mirić Milenko

    2005-01-01

    Full Text Available Four stereoide fungi, causers of decay of oak wood, have been investigated as follows: Stereum hirsutum, Chondrostereum purpureum, Stereum rugosum and Xylobolus frustulatus. The field tests have been undertaken in order to determine the influence of the stereoide fungi on the wood of Sessile oak (Quercus petraea and Austrian oak (Quercus robur. Artificial inoculations with mycelia have been provoked in vital standing trees, as well as in laying trunks. The appearance of dying back symptoms, the rate of mycelia spread through the stem, speed of wound callusing and appearance of fruit bodies or decay symptoms, have been observed. The protection possibility of trunks has been tested as well by using preservatives based on chromo-cupric boron salts, dichlorfluanide and chlorinepyriphos, cupric naphtenates, as well as with antiseptic paste. Microscopically analysis of attacked oak wood has been performed by utilizing of scanning electron (SEM and standard optical microscope providing normal, fluorescence, polarized and UV light, so that anatomical changes of the wood structure elements influenced by fungal activity have been noted.

  20. Bur oak savanna

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This is a summary of research and activities related to bur oak savanna on Neal Smith National Wildlife Refuge between 1992 and 2006. Titles of studies summarized in...

  1. Poison ivy - oak - sumac

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/002886.htm Poison ivy - oak - sumac To use the sharing features ... the plant, if known Amount swallowed (if swallowed) Poison Control Your local poison center can be reached ...

  2. Sweets for the foe - effects of nonstructural carbohydrates on the susceptibility of Quercus robur against Phytophthora quercina.

    Science.gov (United States)

    Angay, Oguzhan; Fleischmann, Frank; Recht, Sabine; Herrmann, Sylvie; Matyssek, Rainer; Oßwald, Wolfgang; Buscot, François; Grams, Thorsten E E

    2014-09-01

    The root-rot pathogen Phytophthora quercina is a key determinant of oak decline in Europe. The susceptibility of pedunculate oak (Quercus robur) to this pathogen has been hypothesized to depend on the carbon availability in roots as an essential resource for defense. Microcuttings of Q. robur undergo an alternating rhythm of root and shoot growth. Inoculation of mycorrhizal (Piloderma croceum) and nonmycorrhizal oak roots with P. quercina was performed during both growth phases, that is, root flush (RF) and shoot flush (SF). Photosynthetic and morphological responses as well as concentrations of nonstructural carbohydrates (NSC) were analyzed. Infection success was quantified by the presence of pathogen DNA in roots. Concentrations of NSC in roots depended on the alternating root/shoot growth rhythm, being high and low during RF and SF, respectively. Infection success was high during RF and low during SF, resulting in a significantly positive correlation between pathogen DNA and NSC concentration in roots, contrary to the hypothesis. The alternating growth of roots and shoots plays a crucial role for the susceptibility of lateral roots to the pathogen. NSC availability in oak roots has to be considered as a benchmark for susceptibility rather than resistance against P. quercina.

  3. 麻栎种子萌发的抑制机制%Inhibitory Mechanism of Seed Germination of Quercus acutissima

    Institute of Scientific and Technical Information of China (English)

    刘艳; 李庆梅; 刘广全; 刘勇; 侯龙鱼; 李国雷

    2012-01-01

    Over the last three decades, decline of oak (Quercus acutissima) natural regeneration has drawn wide attention. Exploration of the causes and development of the seedling technology, which promotes quick and uniform germination of oak seeds, arise interesting of forest researchers. In this paper, the seed cold storage and mechanical damage treatments were studied on germination of Q. acutissima. Methanol extracts of embryo, cotyledon and pericarp of oak seeds were used to investigate existence of inhibitory substance by testing germination of Brassica campestris seeds that were cultivated in Sanyo growth cabinet. The results showed that: (1) removing scar, pericarp, or cutting off a small piece of basal cotyledon increased the rooting rate and percentage, however, cutting off more than 1 /2 cotyledon had negative effects; (2) the seed cold storage accelerated the germination; ( 3 ) Germination rates of B. campestris seeds treated by methanol extracts from embryo of Q. acutissima seeds were significantly lower than control, and inhibitors from embryo, cotyledon and pericarp played a negative role in growth of root and shoot of B. campestris seedlings, indicating that the inhibitors of oak seeds might mainly restrict growth of root and shoot themselves, and be responsible for germinating irregularly. The results have guiding significance for directly seeding afforestation and seedling of Q. acutissima.

  4. Nonlocal symmetries and a Darboux transformation for the Camassa-Holm equation

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Heredero, Rafael [Departamento de Matematica Aplicada, EUIT de Telecomunicacion, Universidad Politecnica de Madrid, Campus Sur Ctra de Valencia Km. 7. 28031, Madrid (Spain); Reyes, Enrique G [Departamento de Matematica y Ciencia de la Computacion, Universidad de Santiago de Chile, Casilla 307 Correo 2, Santiago (Chile)], E-mail: rafahh@euitt.upm.es, E-mail: ereyes@fermat.usach.cl

    2009-05-08

    We announce two new structures associated with the Camassa-Holm (CH) equation: a Lie algebra of nonlocal symmetries, and a Darboux transformation for this important equation, which we construct using only our symmetries. We also extend our results to the associated Camassa-Holm equation introduced by J Schiff (1998 Physica D 121 24-43). (fast track communication)

  5. The Chemical Adventures of Sherlock Holmes: The Ghost of Gordon Square.

    Science.gov (United States)

    Waddell, Thomas G.; Rybolt, Thomas R.

    2000-01-01

    Describes a scientific mystery with an emphasis on chemical magic presented in the context of the characters Sherlock Holmes and Dr. Watson. The story contains a break where students and teachers pause to ponder and solve the mystery. Sherlock Holmes provides his solution in the paragraphs following this break. (WRM)

  6. The Chemical Adventures of Sherlock Holmes: The Ghost of Gordon Square.

    Science.gov (United States)

    Waddell, Thomas G.; Rybolt, Thomas R.

    2000-01-01

    Describes a scientific mystery with an emphasis on chemical magic presented in the context of the characters Sherlock Holmes and Dr. Watson. The story contains a break where students and teachers pause to ponder and solve the mystery. Sherlock Holmes provides his solution in the paragraphs following this break. (WRM)

  7. Bayesian Thought in Early Modern Detective Stories: Monsieur Lecoq, C. Auguste Dupin and Sherlock Holmes

    CERN Document Server

    Kadane, Joseph B

    2010-01-01

    This paper reviews the maxims used by three early modern fictional detectives: Monsieur Lecoq, C. Auguste Dupin and Sherlock Holmes. It find similarities between these maxims and Bayesian thought. Poe's Dupin uses ideas very similar to Bayesian game theory. Sherlock Holmes' statements also show thought patterns justifiable in Bayesian terms.

  8. New Secondary Metabolites from Quercus coccifera L.

    Directory of Open Access Journals (Sweden)

    Didem Şöhretoğlu

    2014-07-01

    Full Text Available Three new secondary metabolites kermesoside (1, cocciferoside (2 and (--8-chlorocatechin (3, were isolated from the the stems with barks of Quercus coccifera along with five known phenolic compounds, 3-hydroxy-1-(4-hydroxy-3-methoxyphenyl-propan-1-one (4 and 3-hydroxy-1-(4-hydroxy-3,5-dimethoxyphenyl-propan-1-one (5, trans-resveratrol-3-O-β-glucopyranoside (6 lyoniresinol-9-O-β-xylopyranoside (7, lyoniresinol-9-O-β-glucopyranoside (8. The structure elucidation of the isolated compounds was performed by spectroscopic methods (UV, 1D- and 2D- NMR and HR-MS.

  9. Development of the rf-SQUID Based Multiplexing System for the HOLMES Experiment

    Science.gov (United States)

    Puiu, A.; Becker, D.; Bennett, D.; Faverzani, M.; Ferri, E.; Fowler, J.; Gard, J.; Hays-Wehle, J.; Hilton, G.; Giachero, A.; Maino, M.; Mates, J.; Nucciotti, A.; Schmidt, D.; Swetz, D.; Ullom, J.; Vale, L.

    2016-07-01

    Measuring the neutrino mass is one of the most compelling issues in particle physics. The European Research Council has funded HOLMES, a new experiment for a direct measurement of neutrino mass that started in 2014. HOLMES will perform a precise measurement of the end point of the Electron Capture decay spectrum of ^{163}Ho in order to extract information on neutrino mass with a sensitivity as low as 0.4 eV. HOLMES, in its final configuration, will deploy a 1000 pixel array of low-temperature microcalorimeters: each calorimeter consists of an absorber, where the Ho atoms will be implanted, coupled to a transition edge sensor thermometer. The read out for an array of 1000 cryogenic detectors is a crucial matter: for HOLMES, a special radio-frequency-based multiplexing system is being developed. In this contribution, we outline the performance and special features of the multiplexing system and readout methods chosen for HOLMES.

  10. Lipschitz metric for the periodic Camassa-Holm equation

    CERN Document Server

    Grunert, Katrin; Raynaud, Xavier

    2010-01-01

    We study stability of conservative solutions of the Cauchy problem for the periodic Camassa-Holm equation $u_t-u_{xxt}+\\kappa u_x+3uu_x-2u_xu_{xx}-uu_{xxx}=0$ with initial data $u_0$. In particular, we derive a new Lipschitz metric $d_\\D$ with the property that for two solutions $u$ and $v$ of the equation we have $d_\\D(u(t),v(t))\\le e^{Ct} d_\\D(u_0,v_0)$. The relationship between this metric and usual norms in $H^1_{\\rm per}$ and $L^\\infty_{\\rm per}$ is clarified.

  11. Genetic diversity increases insect herbivory on oak saplings.

    Directory of Open Access Journals (Sweden)

    Bastien Castagneyrol

    Full Text Available A growing body of evidence from community genetics studies suggests that ecosystem functions supported by plant species richness can also be provided by genetic diversity within plant species. This is not yet true for the diversity-resistance relationship as it is still unclear whether damage by insect herbivores responds to genetic diversity in host plant populations. We developed a manipulative field experiment based on a synthetic community approach, with 15 mixtures of one to four oak (Quercus robur half-sib families. We quantified genetic diversity at the plot level by genotyping all oak saplings and assessed overall damage caused by ectophagous and endophagous herbivores along a gradient of increasing genetic diversity. Damage due to ectophagous herbivores increased with the genetic diversity in oak sapling populations as a result of higher levels of damage in mixtures than in monocultures for all families (complementarity effect rather than because of the presence of more susceptible oak genotypes in mixtures (selection effect. Assemblages of different oak genotypes would benefit polyphagous herbivores via improved host patch location, spill over among neighbouring saplings and diet mixing. By contrast, genetic diversity was a poor predictor of the abundance of endophagous herbivores, which increased with individual sapling apparency. Plant genetic diversity may not provide sufficient functional contrast to prevent tree sapling colonization by specialist herbivores while enhancing the foraging of generalist herbivores. Long term studies are nevertheless required to test whether the effect of genetic diversity on herbivory change with the ontogeny of trees and local adaptation of specialist herbivores.

  12. Spatial pattern of occurrence of epiphytic lichens on oaks in a heterogeneous landscape

    Science.gov (United States)

    Westerberg, Lars M.; Muhammadi, Usman Haider; Bergman, Karl-Olof; Milberg, Per

    2017-10-01

    Quercus robur (oaks) provides an important substrate for many epiphytic lichens, and with increasing age the bark becomes suitable for some rare species. These species may respond to environmental and landscape factors differently, and at different spatial scales. We tested the effect of factors related to the individual tree and the surrounding landscape on the occurrence and richness patterns of lichens species. The study system consisted of 213 oaks selected in a grid system within a 400 km2 heterogeneous oak-rich area in south-eastern Sweden. Oaks had been selected to be relatively uniform in size (circumference 3.1-4.1 m), and as uniformly distributed as possible in the study area. Landscape factors were calculated for various spatial scales (circles with radius ranging from 28 to 1225 m from a studied oak). One of the landscape factors stands out as of general importance - oak density in the surrounding - while the others (amount of forest, water, houses and arable field) had no effects, or weak effects on only some species. Among the tree specific variables, circumference was consistently important (despite ranging from only 3.1-4.1 m) while inconsistent effects were seen by sun exposure of oak trunk (Chaenotheca phaeocephala, Ramalina baltica) and density of shrubs and trees near the tree (Ch. phaeocephala). The occurrence patterns of Cliostomum corrugatum, Ch. phaeocephala, R. baltica and richness (number of eleven target lichens) were best explained by the density of oaks within radii of 401, 199, 199 and 303 m, respectively. In conclusion, our study highlighted the importance of spatial scale for understanding the occurrence of epiphytic lichens and suggests spatial scales and oak densities that could be targeted for landscape and conservation planning.

  13. COENOTICAL CHAINS OF ACER PLATANOIDES AND QUERCUS ROBUR IN THE FORESTS OF NOVGOROD-SEVERSKOYE POLESYE

    Directory of Open Access Journals (Sweden)

    Skliar V. G.

    2012-12-01

    Full Text Available We summarized information on association of small undergrowth of Norway maple (Acer platanoides L. and English oak (Quercus robur L. under the canopy of the forest with plants that form the grass-shrub layer within Novgorod-Severskoye Polesye. We founded that the association at certain extent depends on the type of population behavior of undergrowth and grasses. Small undergrowth of A. platanoides being the tolerant species according to the type of population behavior demonstrates negative association with the herbs that have high competitive ability. The pattern of association of A. platanoides with tolerant species depends on their vegetative mobility: the maple has positive association with species with no vegetative mobility and positive and negative association with species characterized by high extent of vegetative mobility. The undergrowth of Q. robur which is the competitive species due to population behavior shows positive association with the herbs that have high competitive ability. We estimated the coenotic parameters that are required for successful resumption of maple and oak in the region of research. We also shown that coenotic optimum for A. platanoides corresponds to the environment with weak intensity of competition in the living soil cover with thin grass layer and density of coverage does not exceed 50%. Q. robur has coenotic optimum among habitats in the herbaceous layer with domination of green moss and (or Convallaria majalis L., Fragaria vesca L. with no grains and density of coverage in living ground cover not more than 60%.

  14. A comparative analysis of stomata and leaf trichome characteristics in Quercus robur L. genotypes

    Directory of Open Access Journals (Sweden)

    Nikolić Nataša P.

    2003-01-01

    Full Text Available The objective of this study was to determine genotype variability of leaf trichome and stoma characteristics. Leaves were sampled from seventeen pedunculate oak (Quercus robur L genotypes originating from clonal seed orchard Banov Brod (Srem, the Vojvodina Province. The pedunculate oak has hypostomatal leaves. Statistically significant differences were found for the dimensions and density of stomata. Genotype variability of stomatal dimensions was less pronounced in comparison with their density (CV = 8.88%. Stomata number ranged from 530 to 791 per mm2 of leaf area; genotypes 18 and 25 could be distinguished from the others for the highest stomata number per leaf unit area, genotype 35 for the lowest number. In all genotypes, only solitary eglandular trichomes were observed on the adaxial leaf surface while both solitary eglandular and uniseriate glandular hairs were present on the abaxial surface. Single glandular trichomes were observed in all genotypes, while some of them were characterized by the presence of two (genotypes 4, 5, 6, 16, 22, 25, 28, 29, 30, 35, 38, 40, and 85 or three (genotypes 16, 25, 35 hairs joined by their basal cells.

  15. Assessment of ploidy stability of the somatic embryogenesis process in Quercus suber L. using flow cytometry.

    Science.gov (United States)

    Loureiro, J; Pinto, G; Lopes, T; Dolezel, J; Santos, C

    2005-08-01

    Flow cytometry analyses were used to verify the ploidy stability of Quercus suber L. somatic embryogenesis process. Leaf explants of two adult cork oak trees (QsG0 and QsG5) of the North of Portugal were inoculated on MS medium with 2,4-D and zeatin. After 3 months, calluses with embryogenic structures were isolated and transferred to fresh MS medium without growth regulators and somatic embryo evolution was followed. Morphologically normal somatic embryos (with two cotyledons) and abnormal somatic embryos (with one or three cotyledons) were used in this assay. Flow cytometry combined with propidium iodide staining was employed to estimate DNA ploidy levels and nuclear DNA content of somatic embryos and leaves from mother plants. No significant differences (P< or =0.05) were detected among embryos, and between the embryos and the mother plants. Also, after conversion of these embryos, no significant morphological differences were observed among the somatic embryo-derived plants. These results and further studies using converted plantlet leaves and embryogenic callus tissue indicate that embryo cultures and converted plantlets were stable with regard to ploidy level. As no major somaclonal variation was detected our primary goal of "true-to-type" propagation of cork oak using somatic embryogenesis was assured at this level. The estimation of the 2C nuclear DNA content for this species is similar to the previously obtained value.

  16. Studies on the ectomycorrhizal community in a declining Quercus suber L. stand.

    Science.gov (United States)

    Lancellotti, Enrico; Franceschini, Antonio

    2013-10-01

    This survey was carried out in a Quercus suber L. stand with many trees affected by the disease "oak decline". Its aim was to obtain information about both the belowground ectomycorrhizal fungal community in a declining Q. suber stand as a whole, and the ectomycorrhizal fungal community of individual tree (EFT) detected in healthy and diseased plants. To this end, we first categorized the trees into four different decline classes (one for healthy plants and three for diseased plants) and then, by using morphological and molecular tools, we identified the ectomycorrhizas isolated from samples collected near the trees with different declining classes. The ectomycorrhizal community as a whole was seen to be composed of numerous ectomycorrhizal fungal species, only some of which appeared to be dominant (Cenococcum geophilum, Lactarius chrysorrheus, and some species of Tomentella genus), while most occurred sporadically. Results show that all root tips observed are mycorrhized and that decline class does not influence the number of ectomycorrhizal root tips found in the EFTs, thus oak decline does not impact the investment in ectomycorrhizal symbiosis. However, some statistical differences can be observed in the values of evenness and taxonomic distinctness in the EFT associated with trees with different states of health. Finally, both the analysis of similarity test and the ordination technique highlight a compositional difference between the EFT associated with trees in different health conditions, but also suggest that other factors may play a role in causing these differences.

  17. Histology of Organogenic and Embryogenic Responses in Cotyledons of Somatic Embryos of Quercus Suber L.

    Science.gov (United States)

    Puigderrajols; Celestino; Suils; Toribio; Molinas

    2000-05-01

    In cork oak (Quercus suber L.), recurrent embryogenesis is produced in vitro through autoembryony without exogenous plant growth regulators (PGRs); secondary embryos appear on the embryo axis but seldom on cotyledons. Focusing mainly on the histological origin of neoformations, we investigated the influence of the embryo axis and exogenous PGRs on the embryogenic potential of somatic embryo cotyledons. Isolated cotyledons of somatic embryos became necrotic when cultured on PGR-free medium but gave secondary embryos when cultured on media containing benzyladenine and naphthaleneacetic acid. Cotyledons of cork oak somatic embryos are competent to give embryogenic responses. Isolated cotyledons without a petiole showed a lower percentage of embryogenic response than did those with a petiole. In petioles, somatic embryos arose from inner parenchyma tissues following a multicellular budding pattern. Joined to the embryo axis, cotyledons did not show morphogenic responses when cultured on PGR-free medium but revealed budlike and phylloid formations when cultured on medium with PGRs. The different morphogenic behavior displayed by somatic cotyledons indicates an influence of the embryo axis and indicates a relationship between organogenic and embryogenic regeneration pathways.

  18. Site quality assessment of degraded Quercus frainetto stands in central Greece

    Directory of Open Access Journals (Sweden)

    Kitikidou K

    2015-02-01

    Full Text Available The potential yield of a site is measured by site index, which is defined as the dominant height of a stand at a base age. A site index model for site quality assessment of Quercus frainetto (Hungarian oak stands in central Greece was developed using a base age of 50 years. Data were collected from 39 temporary sample plots of 10 x 10 m. Linear regression models widely used in site index studies were fitted to height-age data. The adjusted coefficient of determination (R2adj, root mean square error (RMSE, bias, coefficient of determination for the prediction (R2pr and residual plots were used for the choice of the best-fitting model. The best model was H = -0.231+0.251A-0.001A2, where H is the predicted height at age A. The guide curve method was adopted in constructing the sites curves, with the chosen model as the guide curve. Based on this curve, the study area was divided into three site quality classes (I to III, with class I representing the best and class III the poorest. Also, the presence of a Simpson’s paradox in these analyses is discussed. The results showed that a 50-year-old stand in the study area attained an average dominant height of about 11, 8 and 6 m on site quality classes I, II and III, respectively. The Hungarian oak stands of the present study can be considered very low productivity stands.

  19. Epigenetic and hormonal profile during maturation of Quercus Suber L. somatic embryos.

    Science.gov (United States)

    Pérez, Marta; Viejo, Marcos; LaCuesta, Maite; Toorop, Peter; Cañal, María Jesús

    2015-01-15

    Somatic embryogenesis is a powerful alternative to conventional mass propagation of Quercus suber L. However, poor quality and incomplete maturation of somatic embryos restrict any application. Given that epigenetic and hormonal control govern many developmental stages, including maturation of zygotic embryos, global DNA methylation and abscisic acid (ABA) were analyzed during development and maturation of cork oak somatic embryos. Our results indicated that development of somatic embryos concurred with a decrease in 5-mdC. In contrast, endogenous ABA content showed a transient increase with a peak in immature E2 embryos denoting the onset of the maturation phase. A cold stratification phase was necessary for embryos to acquire germination ability, which coincided with a significant decrease in 5-mdC and ABA content. Immunohistochemical analyses showed that there was a specific spatial-temporal regulation during embryogenesis, particularly after the cold treatment. The acquisition of germination capacity concurred with a general low 5-mdC signal in the root meristem, while retention of the 5-mdC signal was mainly located in the shoot meristem and provascular tissues. Conversely, ABA immunolocalization was mainly located in the root and shoot apical meristems. Furthermore, a strong decrease in the ABA signal was observed in the root cap after the stratification treatment suggesting a role for the root cap during development of somatic embryos. These results suggest that, in addition to ABA, epigenetic control appears to play an important role for the correct maturation and subsequent germination of cork oak somatic embryos.

  20. The distribution of Quercus suber chloroplast haplotypes matches the palaeogeographical history of the western Mediterranean.

    Science.gov (United States)

    Magri, D; Fineschi, S; Bellarosa, R; Buonamici, A; Sebastiani, F; Schirone, B; Simeone, M C; Vendramin, G G

    2007-12-01

    Combining molecular analyses with geological and palaeontological data may reveal timing and modes for the divergence of lineages within species. The Mediterranean Basin is particularly appropriate for this kind of multidisciplinary studies, because of its complex geological history and biological diversity. Here, we investigated chloroplast DNA of Quercus suber populations in order to detect possible relationships between their geographical distribution and the palaeogeographical history of the western Mediterranean domain. We analysed 110 cork oak populations, covering the whole distribution range of the species, by 14 chloroplast microsatellite markers, among which eight displayed variation among populations. We identified five haplotypes whose distribution is clearly geographically structured. Results demonstrated that cork oak populations have undergone a genetic drift geographically consistent with the Oligocene and Miocene break-up events of the European-Iberian continental margin and suggested that they have persisted in a number of separate microplates, currently found in Tunisia, Sardinia, Corsica, and Provence, without detectable chloroplast DNA modifications for a time span of over 15 million years. A similar distribution pattern of mitochondrial DNA of Pinus pinaster supports the hypothesis of such long-term persistence, in spite of Quaternary climate oscillations and of isolation due to insularity, and suggests that part of the modern geographical structure of Mediterranean populations may be traced back to the Tertiary history of taxa.

  1. Comparison of the autoecology of Quercus robur L. and Q. petraea (Mattuschka Liebl. stands in the Northwest of the Iberian Peninsula

    Directory of Open Access Journals (Sweden)

    A. Rodriguez-Campos

    2010-09-01

    Full Text Available The purpose of the present work is to characterize the functioning of the ecosystems of semideciduous and deciduous Atlantic oaks in the northwest of the Iberian Peninsula. The studied species were: Quercus robur L. and Quercus petraea (Mattuschka Liebl. To advance in the knowledge of the autecology of these species it is necessary to descend at the regional level and describe in detail the variability of the environment to determine their potential, and to decide the silvicultural treatments to be applied to preserve them and to analyze future actuations in order to a possible expansion. The analysis of the results allows knowing differences in continentalityand site conditions, with more precipitation, soil variability and humidification in Q. petraea forests respect to Q. robur. These information represent appropriate measures for the sustainable and multifunctional management of these forests, useful as indicators environmental and forestry parameters as well as the conservationstatus of these formations.

  2. Stand Structure, Productivity and Carbon Sequestration Potential of Oak Dominated Forests in Kumaun Himalaya

    Directory of Open Access Journals (Sweden)

    Bijendra Lal

    2016-08-01

    Full Text Available Present study deals with stand structure, biomass, productivity and carbon sequestration in oak dominated forests mixed with other broad leaved tree species. The sites of studied forests were located in Nainital region between 29058’ N lat. and 79028’ E long at 1500-2150 m elevation. Tree density of forests ranged from 980-1100 ind.ha-1. Of this, oak trees shared 69-97%. The basal area of trees was 31.81 to 63.93 m2 ha-1. R. arboreum and Q. floribunda shared maximum basal area 16.45 and 16.32 m2 ha-1, respectively in forest site-1 and 2 while Quercus leucotrichophora shared maximum (35.69 m2 ha-1 in site-3. The biomass and primary productivity of tree species ranged from 481-569 t ha-1 and 16.9-20.9 t ha-1yr-1, respectively. Of this, biomass and primary productivity of oak tree species accounted for 81 to 95 and 78 to 98%, respectively. Carbon stock and carbon sequestration ranged from 228 to 270 t ha-1 and 8.0 to 9.9 t ha-1yr-1, respectively. The share of oak tree species ranged from 81 to 94.7 and 79 to 97%, respectively. The diversity of tree species ranged from 0.03 to 0.16 in forest sites-1, 2 and 3. The diversity of oak species was 0.08-0.16 in all the forest sites. Thus it is concluded that among the oak tree species, Quercus floribunda and Quercus leucotrichophora were highly dominated in the studied forests. The climax form of oak dominated trees in the studied forest sites depicted slightly lower richness and diversity of tree species compared to the forests in the region and elsewhere. As far as dry matter and carbon of forests is concerned, these estimates are close to the earlier reports of forests in the region. Therefore, studied forests have the potential to increase the diversity, productivity and carbon sequestration of forest tree species by providing the adequate scientific conservation and management inputs.

  3. Within-population variability influences early seedling establishment in four Mediterranean oaks

    Science.gov (United States)

    González-Rodríguez, Victoria; Barrio, Isabel C.; Villar, Rafael

    2012-05-01

    Regeneration of Mediterranean forests is severely limited. Multiple abiotic factors are known to constrain the establishment of woody seedlings at its first phases, such as summer drought or excessive incident radiation, but less attention has been paid to the role of intra-specific variation in seedling performance. In this study we investigate the relative influence of environment (light availability, soil moisture and summer irrigation) and intrinsic factors (seed mass and maternal origin) as determinants of within-population variability in the early establishment of four coexisting Mediterranean oaks (Quercus ilex, Quercus suber, Quercus faginea and Quercus pyrenaica), from emergence and early growth to second-year survival in a field experiment. Seed size was a poor predictor of seed and seedling success. Instead, mother identity showed a stronger effect on seedling performance. Time and percentage of emergence, establishment success and morphological traits varied among seedlings from different maternal trees but main drivers for each variable were different for each species. In addition to a direct effect, in many cases mother-related intrinsic traits and seed mass influenced the effects of environmental conditions on seedling performance. The role of intrinsic factors was masked under ameliorated conditions (i.e. summer irrigation), indicating the relevant role of within-population variability to cope with highly heterogeneous and unpredictable Mediterranean environments.

  4. Molecular and morphological characterization of a Xiphinema chambersi population from live oak trees in Jekyll Island, Georgia, with a redescription of the species and comments on its morphometric variations

    Science.gov (United States)

    A population of Xiphinema chambersi from the root zone around live oak (Quercus virginiana Mill.) trees on Jekyll Island, Georgia, USA is described using both morphological and molecular tools and compared with descriptions of type specimens. Initially, because of a few morphological differences thi...

  5. Characterization of Acorn Fruit Oils Extracted from Selected Mediterranean Quercus Species

    Directory of Open Access Journals (Sweden)

    Al-Rousan, W. M.

    2013-12-01

    Full Text Available The present study is aimed to identifying the acorn fruit oil composition of three Mediterranean white oak group species, Quercus aegilops (QA, Quercus infectoria (QI, and Quercus calliprinus (QC. Samples were estimated for the oil contents of acorn fruits, oil chemical and physical constants, fatty acid profile, tocopherols, phenolic compounds, and sterols.The oil content, expressed as dry weight, was found to be 3.40-7.51%. The physical and chemical constants included specific gravity 0.912-0.922, refractive index 1.4529-1.4645, specific extinction at 232 nm 2.497-2.536 and at 270 nm 1.495-2.037, iodine value 75.2-87.6, and saponification value 192.6-219.4. The fatty acid compositions were determined by GC as methyl esters. The most abundant fatty acids were oleic (53.3-56.1%, linoleic 21.3-23.4%, palmitic 17.8-18.7%, linolenic 1.5-1.6% and stearic acid 1.02-1.60%. The Tocopherol content was high in the range of 1440-1783 mg kg-1, γ-tocopherol constituted 84-91% of total tocopherols. Phenolic compounds were in remarkable amounts in all the three species 84-109 mg gallic acid kg-1 oil. Total sterol contents were between 2040-2480 mg kg-1 oil, with β-sitosterol being the main component comprising of 77.20-84.61%, followed by ∆5-avenasterol (5.8-11.4%, campesterol (3.6-4.5%, and stigmasterol (2.6-3.8. The cholesterol content was relatively high (0.42-0.55%.El presente estudio tuvo como objetivo identificar la composición de aceites de bellota de tres especies del grupo del roble blanco del Mediterráneo, Quercus Aegilops (QA, Quercus infectoria (QI y Quercus calliprinus (QC. Las muestras fueron evaluadas por el contenido de aceite, parámetros físico-químicos del aceite, perfil de ácidos grasos, tocoferoles, compuestos fenólicos y esteroles. El contenido de aceite, expresado en peso seco encontrado fue de 3,40 a 7,51%. Las constantes físico-químicas fueron: densidad 0,912-0,922, índice de refracción 1,4529 a 1,4645, extinción espec

  6. Poison Ivy/Oak/Sumac

    Science.gov (United States)

    ... Your 1- to 2-Year-Old First Aid: Poison Ivy/Oak/Sumac KidsHealth > For Parents > First Aid: Poison Ivy/Oak/Sumac Print A A A The oil in poison ivy /oak/sumac plants (called urushiol ) can cause ...

  7. Associations between growth, wood anatomy, carbon isotope discrimination and mortality in a Quercus robur forest.

    Science.gov (United States)

    Levanic, Tom; Cater, Matjaz; McDowell, Nate G

    2011-03-01

    Observations of forest mortality are increasing globally, but relatively little is known regarding the underlying mechanisms driving these events. Tree rings carry physiological signatures that may be used as a tool for retrospective analyses. We capitalized on a local soil water drainage event in 1982 that resulted in increased mortality within a stand of oak trees (Quercus robur), to examine the underlying physiological patterns associated with survival and death in response to soil water limitations. Pre-dawn water potentials showed more negative values for trees in the process of dying compared with those that survived. We used tree rings formed over the 123 years prior to mortality to estimate productivity from basal area increment (BAI, mm(2)), multiple xylem hydraulic parameters via anatomical measurements and crown-level gas exchange via carbon isotope discrimination (Δ, ‰). Oaks that died had significantly higher BAI values than trees that survived until the drainage event, after which the BAI of trees that died declined dramatically. Hydraulic diameter and conductivity of vessels in trees that died were higher than in surviving trees until the last 5 years prior to mortality, at which time both groups had similar values. Trees that died had consistently lower Δ values than trees that survived. Therefore, tree mortality in this stand was associated with physiological differences prior to the onset of soil water reduction. We propose that trees that died may have been hydraulically underbuilt for dry conditions, which predisposes them to severe hydraulic constraints and subsequent mortality. Measurements of above-ground/below-ground dry mass partitioning will be critical to future tests of this hypothesis. Based on these results, it is probable that pedunculate oak trees will experience greater future mortality if climate changes cause more severe droughts than the trees have experienced previously.

  8. Transpiration of montane Pinus sylvestris L. and Quercus pubescens Willd. forest stands measured with sap flow sensors in NE Spain

    Directory of Open Access Journals (Sweden)

    R. Poyatos

    2005-01-01

    Full Text Available Stand transpiration was measured during the 2003 and 2004 growing seasons using heat dissipation sap flow sensors in a Scots pine (Pinus sylvestris L. and a pubescent oak (Quercus pubescens Willd. forests located in a montane area of the Eastern Pyrenees (NE Spain. The first aim of the study was to assess the differences in quantitative estimates of transpiration (Ec and the response to evaporative demand of the two stands. Over the studied period of 2003, characterised by a severe drought episode during the summer, the oak stand (Ec was only 110 mm compared to the 239 mm transpired by the Scots pine stand, although the ratio of transpiration to reference evapotranspiration (Ec/ET0 in the oak stand compares well with the expected values predicted for low leaf area index (LAI oak forests in southern Europe. Scots pine showed a strong reduction in (Ec/ET0 as the drought developed, whereas pubescent oak was less affected by soil moisture deficits in the upper soil. As a second objective, and given the contrasting meteorological conditions between 2003 and 2004 summer periods, the interannual variability of transpiration was studied in the Scots pine plot. Rainfall during the summer months (June-September in 2003 was almost 40% less than in the same interval in 2004. Accordingly, transpiration was also reduced about 25% in 2003. Finally, Scots pine data from 2003 and 2004 was used to calibrate a simple transpiration model using ET0 and soil moisture deficit (SMD as input variables, and implicitly including stomatal responses to high vapour pressure deficits (Dd and soil water status.

  9. Characterization of the Oxygen Transmission Rate of Oak Wood Species Used in Cooperage.

    Science.gov (United States)

    Del Alamo-Sanza, María; Cárcel, Luis Miguel; Nevares, Ignacio

    2017-01-25

    The oxygen that wine receives while aged in barrels is of interest because it defines the reactions that occur during aging and, therefore, the final properties of the wine. This study is intended to make up for the lack of information concerning the oxygen permeability of eight different woods of Quercus alba L. and Quercus petraea (Matt.) Liebl. commonly used. In addition, it shows how oxygen transfer evolves with the liquid contact time during testing under similar aging conditions to those in wine barrels. French oak woods permitted a higher oxygenation rate than American ones in all cases. A decrease in the oxygen entry caused by impregnation of the wood during the process was observed in all of the species studied. This process is determined by the thickness of the flooded wood layer containing free water, although differently in the two species, possibly due to the anatomical structure and the logging process for each.

  10. Hydrologic effects on diameter growth phenology for Celtis laevigata and Quercus lyrata in the floodplain of the lower White River, Arkansas

    Science.gov (United States)

    Allen, Scott T; Cochran, Wesley; Krauss, Ken W.; Keim, Richard F.; King, Sammy L.; Schweitzer, Callie Jo; Clatterbuck, Wayne K.; Oswalt, Christopher M.

    2016-01-01

    Bottomland hardwood (BLH) forests represent an extensive wetland system in the Mississippi Alluvial Valley and southeastern USA, and it is currently undergoing widespread transition in species composition. One such transition involves increased establishment of sugarberry (Celtis laevigata), and decreased establishment of overcup oak (Quercus lyrata). The ecological mechanisms that control this transition are not well understood. We measured monthly diameter growth with dendrometer bands on 86 sugarberry and 42 overcup oak trees at eight sites in the floodplain of the White River (AR, USA) with differing hydrologic regimes. For both species, growth attenuated earlier at drier sites compared to wetter sites. Overcup oak grew slightly longer through late August, suggesting its growth period extends across both wet and dry periods. In contrast, sugarberry growth rate decreased substantially by mid-July. While these results did not necessarily indicate a mechanism for increased prominence of sugarberry, they suggest sugarberry growing season does not as much coincide with the typically drier period of late summer and may be less affected by these conditions. Overcup oak grows later into the dry season and water table conditions during this period may determine if overcup oak benefits from this relatively extended growth period.

  11. Predicting internal white oak (Quercus alba) log defect features using surface defect indicator measurements

    Science.gov (United States)

    Ralph E. Thomas

    2012-01-01

    As hardwood trees grow and develop, surface defects such as limb stubs and wounds are overgrown and encapsulated into the tree. Evidence of these defects can remain on the tree's surface for decades and in many instances for the life of the tree. The location and severity of internal defects dictate the quality and value of products that can be obtained from logs...

  12. Bird diversity in Turkey oak (Quercus cerris coppices and transitory stands in the northern Apennines

    Directory of Open Access Journals (Sweden)

    Tellini Florenzano G

    2012-07-01

    Full Text Available In the last decades, socio-economical changes occurred in Italy have deeply affected woodland, particularly coppices. Although most of them, above all in public land, are being converted to high forests, in the last years coppices have been experiencing an increase in their use. The claimed need to reconcile silviculture and biodiversity conservation calls for a better understanding of the effects of coppice management practices on the different components of biodiversity. Using birds as environmental indicators, we studied differences in species composition and diversity of bird communities in coppices and “transitory stands” (ex-coppices recently converted in high stands in the Alpe della Luna forest (Arezzo, in Tuscan Apennines. Relative frequency of each species and the mean abundance and richness at point level were compared among forest typologies. To test the effects of different management types on bird communities, descriptive models (GLM have been applied using stand age and the amount of non-forest habitats as predictors. Our results show that 34.4% of the species (57.1% considering only forest species are affected by the forest management type: 9 species (7 considering only forest species were more common in transitory stands, while only two (of which one considered forest species in coppices. Overall, richness is higher in transitory stands, where species of mature forests have been found; on the contrary, coppices did not host any open habitat species, as stated in other studies. Richness in forest species is positively related to stand age for both coppice and transitory stands; the amount of open habitats is positively correlated with number of open-habitat species, but it did not negatively affect richness in forest species that apparently did not suffer for any boundary effect.

  13. EFFECTS OF STEAMING AND MICROWAVE PRETREATMENTS ON MASS TRANSFER CHARACTERISTICS OF ALEPPE OAK (QUERCUS INFECTORIA

    Directory of Open Access Journals (Sweden)

    Hadi Dashti,

    2012-06-01

    Full Text Available In this research, effects of steaming and microwave pretreatments on the mass transfer properties of never-dried Q. infectoria were investigated. Specimens at green moisture content were exposed to microwaves of frequency 2450 MHz for 10 minutes. The pre-steaming was performed at a temperature of 160°C for 1 hour under a pressure of 2 to 3 bars. Air permeability values were measured to be 4.8 and 4.9 (× 10-16 m3 m-1 in the sapwood and heartwood, respectively. Results showed a significant general increase in the air permeability and diffusion coefficients in the pretreated sapwood specimens. The presence of tyloses in the heartwood prevented the penetration of steam to the inner parts of the specimens, resulting in the diffusion coefficient remaining constant. The pressure gradient caused by the microwave heating resulted in the distortion of the tyloses structure in the heartwood, thus resulting in a significant increase in the air permeability. It may be concluded that the presence of tyloses has a significant effect on the final impact of either of the pretreatments.

  14. Vestiture and trichome types of the oaks of forests in Western Iran

    Directory of Open Access Journals (Sweden)

    Mohammad Mehrnia

    2014-11-01

    Full Text Available The Quercus is the main genus of the Fagaceae with about 300 to 600 species in the world. Both the vestiture and trichome types are important in the taxonomy of Quercus species and hybrids. Although particular terms have been used for a long time, the terminology for both vestiture and trichome types has not been standardized, glossaries differ in their definitions and illustrations and floristic manuals vary markedly in their descriptions of the species. In this study, the vestiture and trichomes were described and illustrated for seven species of oaks in the Zagros Mountains. The terminology of trichome types was determined based upon Hardin (1976. Samples for SEM studies of each species were collected from fresh material of early spring and mature leaves and specimens which were deposited in the Herbaria. The ten types of trichomes were distinguished for the Zagros oaks as follows: 1 Simple-thin-walled, 2 Rosulate-rosette, 3 Solitary-long, 4 Fasciculate-erect, 5 Multiradiate, 6 Stellate, 7 Fused-stellate, 8 Appressed-Lateral, 9 Atipic stellate, 10 Multinodal stellate. Based on trichome types two major infrageneric groups were recognized for western of Iran: the cerroid and roburoid oaks matched our results based on ITS data.

  15. Management of oak forests

    DEFF Research Database (Denmark)

    Löf, Magnus; Brunet, Jörg; Filyushkina, Anna

    2016-01-01

    uses. Management for the production of high-value timber species like oaks and management to conserve biodiversity, or for cultural services can be in conflict with each other. This study evaluates the capacity of three contrasting management regimes to provide societies with economic revenue from...

  16. Phytosociological studies of the forests with sessile oak and Norway spruce from South-Eastern Transylvania

    Directory of Open Access Journals (Sweden)

    Adrian Indreica

    2011-02-01

    Full Text Available The forests with sessile oak (Quercus petraea and Norway spruce (Picea abies from south-eastern Transylvania represent a peculiar type of phytocenoses, rather unusual for the present-day vegetation of Romania’s territory. Aim of the study is to provide a detailed description of the vegetation and to identify the phytosociological and typological units to which it could belong. Beside this, stand structure and regeneration status of the main tree species are illustrated. The studied area is located around Carpathian intermountain depressions Braşov and Ciuc, where vegetation had a peculiar history and today sessile oak forests on high altitude exists, interfering with spruce forests. The hypothesis of the process naturalness is supported by vegetation history in the area, climate, stand structure and peculiarities of herb layer composition (the mixture of relic of both mountain-boreal origin and south-European origin, like Vaccinium vitis-idaea, Pyrola rotundifolia and respectively Potentilla micrantha, Lathyrus venetus respectively. Sintaxonomically, studied phytocenoses with sessile oak and spruce belong mainly to acidophilus oak forests (Luzulo luzuloidis-Quercetum petraeae, but some of them resemble oak-hornbeam forests (Carici pilosae-Carpinetum, indicating a more recent change in stand structure and suggesting that not the soil, but the climate is the driving force of succession. Regeneration of sessile oak is at least satisfactory, but the expansion of spruce in such stands could seriously restrict the survival of sessile oak. A new typological unit will be appropriate,for a better management of sessile oak forests with spruce admixture.

  17. Was the real Sherlock Holmes a pediatric surgeon?

    Science.gov (United States)

    Raffensperger, John

    2010-07-01

    This article reviews the pioneering efforts of Joseph Bell, the model for Sherlock Holmes, in the surgical care of children during the antiseptic era. I reviewed biographies of Sir Arthur Conan Doyle; the biography of Joseph Bell; his surgical textbook, Edinburgh Medical Journals; and the history of the Royal Edinburgh Hospital for Sick Children. Dr Bell was a colleague of Joseph Lister and one of the first surgeons to apply antiseptic methods to operations involving children. He was the surgeon appointed to the first surgical ward of the Royal Edinburgh Hospital for Sick Children; in that role, he cared for many children with surgical diseases. Dr Joseph Bell, by his compassion for children and his surgical skill, was indeed a pioneer pediatric surgeon. Copyright 2010 Elsevier Inc. All rights reserved.

  18. Water outburst activity in Comet 17P/Holmes

    Science.gov (United States)

    de Almeida, Amaury A.; Boice, Daniel C.; Picazzio, Enos; Huebner, Walter F.

    2016-08-01

    Cometary outbursts are sporadic events whose mechanisms are not well known where the activity and consequently the brightness can increase hundreds of thousands of times within a few hours to several days. This indicates a dramatic departure from thermal equilibrium between the comet and interplanetary space and is usually documented by ;light curves;. In a typical cometary outburst, the brightness can increase by 2-5 magnitudes (Whitney, 1955; Gronkowski and Wesolowski, 2015). In only 42 h, Comet 17P/Holmes was reported to brighten from a magnitude of about 17 to about 2.4 at the height of the burst, representing the largest known outburst by a comet. We present the H2O production rate of Holmes for the megaburst occurring between 23 and 24 October 2007. For this, we selected more than 1900 photometric observations from the International Comet Quarterly Archive of Photometric Data (Green, 2007) and use the Semi-Empirical Method of Visual Magnitudes (SEMVM; de Almeida et al., 2007). We clearly show that the comet achieved an average water production rate of 5 × 1029 molecules s-1, corresponding to a water gas loss rate of 14,960 kg s-1, in very good agreement with Schleicher (2009) who derived the water production rate using OH measurements on 1 Nov 2007 (about 8 days after the outburst). We discuss possible physical processes that might cause cometary outbursts and propose a new qualitative mechanism, the Pressurized Obstructed Pore (POP) model. The key feature of POP is the recrystallization of water in the surface regolith as it cools, plugging pores and blocking the release of subsurface gas flow. As the interior gas pressure increases, an outburst is eventually triggered. POP is consistent with current observations and can be tested in the future with observations (e.g., Rosetta in situ measurements) and detailed simulations.

  19. Pile-Up Discrimination Algorithms for the HOLMES Experiment

    Science.gov (United States)

    Ferri, E.; Alpert, B.; Bennett, D.; Faverzani, M.; Fowler, J.; Giachero, A.; Hays-Wehle, J.; Maino, M.; Nucciotti, A.; Puiu, A.; Ullom, J.

    2016-07-01

    The HOLMES experiment is a new large-scale experiment for the electron neutrino mass determination by means of the electron capture decay of ^{163}Ho. In such an experiment, random coincidence events are one of the main sources of background which impair the ability to identify the effect of a non-vanishing neutrino mass. In order to resolve these spurious events, detectors characterized by a fast response are needed as well as pile-up recognition algorithms. For that reason, we have developed a code for testing the discrimination efficiency of various algorithms in recognizing pile up events in dependence of the time separation between two pulses. The tests are performed on simulated realistic TES signals and noise. Indeed, the pulse profile is obtained by solving the two coupled differential equations which describe the response of the TES according to the Irwin-Hilton model. To these pulses, a noise waveform which takes into account all the noise sources regularly present in a real TES is added. The amplitude of the generated pulses is distributed as the ^{163}Ho calorimetric spectrum. Furthermore, the rise time of these pulses has been chosen taking into account the constraints given by both the bandwidth of the microwave multiplexing read out with a flux ramp demodulation and the bandwidth of the ADC boards currently available for ROACH2. Among the different rejection techniques evaluated, the Wiener Filter technique, a digital filter to gain time resolution, has shown an excellent pile-up rejection efficiency. The obtained time resolution closely matches the baseline specifications of the HOLMES experiment. We report here a description of our simulation code and a comparison of the different rejection techniques.

  20. Comparative analysis of different methods for evaluating quality of Quercus ilex seedlings inoculated with Tuber melanosporum.

    Science.gov (United States)

    Andrés-Alpuente, Antonio; Sánchez, Sergio; Martín, María; Aguirre, Angel Javier; Barriuso, Juan J

    2014-04-01

    The quality of seedlings colonized by Tuber melanosporum is one of the main factors that contributes to the success or failure of a truffle crop. Truffle cultivation has quickly grown in European countries and elsewhere, so a commonly shared seedling evaluation method is needed. Five evaluation methods are currently published in the literature: three are used in Spain and two in France and Italy. Although all estimate the percentage colonization by T. melanosporum mycorrhizae, they do it in different ways. Two methods also estimate total number of mycorrhizae per seedling. Most are destructive. In this work, ten batches of holm oak seedlings inoculated with T. melanosporum from two different nurseries were evaluated by means of the five methods noted above. Some similarity was detected between the percentages of T. melanosporum mycorrhizae estimated by each method but not in their ability to assess the suitability of each batch. We discuss the advantages and disadvantages for each method and suggest approaches to reach consensus within the truffle culture industry for certifying mycorrhizal colonization by T. melanosporum and seedling quality.

  1. Effect of flooding on C metabolism of flood-tolerant (Quercus robur) and non-tolerant (Fagus sylvatica) tree species.

    Science.gov (United States)

    Ferner, Eleni; Rennenberg, Heinz; Kreuzwieser, Jürgen

    2012-02-01

    Flooding is assumed to cause an energy crisis in plants because-due to a lack of O(2)-mitochondrial respiration is replaced by alcoholic fermentation which yields considerably less energy equivalents. In the present study, the effect of flooding on the carbon metabolism of flooding-tolerant pedunculate oak (Quercus robur L.) and flooding-sensitive European beech (Fagus sylvatica L.) seedlings was characterized. Whereas soluble carbohydrate concentrations dropped in roots of F. sylvatica, they were constant in Q. robur during flooding. At the same time, root alcohol dehydrogenase activities were decreased in beech but not in oak, suggesting substrate limitation of alcoholic fermentation in beech roots. Surprisingly, leaf and phloem sap sugar concentrations increased in both species but to a much higher degree in beech. This finding suggests that the phloem unloading process in flooding-sensitive beech was strongly impaired. It is assumed that root-derived ethanol is transported to the leaves via the transpiration stream. This mechanism is considered an adaptation to flooding because it helps avoid the accumulation of toxic ethanol in the roots and supports the whole plant's carbon metabolism by channelling ethanol into the oxidative metabolism of the leaves. A labelling experiment demonstrated that in the leaves of flooded trees, ethanol metabolism does not differ between flooded beech and oak, indicating that processes in the roots are crucial for the trees' flooding tolerance.

  2. Root vitality of Fagus sylvatica L., Quercus petraea Liebl. and Acer pseudoplatanus L. in mature mixed forest stand

    Directory of Open Access Journals (Sweden)

    Grygoruk Dorota

    2016-06-01

    Full Text Available The main task of the present study was to investigate the root vitality of common beech Fagus sylvatica L., sessile oak Quercus petraea Liebl. and sycamore maple Acer pseudoplatanus L. in the optimal g rowth conditions in south-western Poland. The study was carried out in 130-year-old mixed stand located within natural range of studied tree species. The density of roots (g/100 cm3 of soil and biomass of fine roots (g/m2 in topsoil layers (0-5 cm, 5-15 cm were determined in the tree biogroups of the same species. The mean total root density ranged from 0.248 to 0.417 g/100 cm3 in the 0-5 cm soil layer, and it decreased in the deeper soil layer (5-15 cm. There were found no statistically significant differences of total root densities between tree biogroups in topsoil layers. Diversity of fine root biomass was comparable in the tree biogroups (H’ = 1.5, but common beech showed more intensive growth of fine roots in the topsoil 0-15 cm when compared to sessile oak and sycamore maple. The results of the study point out the stability of the multi-species structure of the mixed stand studied, and consequently - the ability of beech, sessile oak and sycamore maple trees to coexist in the mixed stands - in the area of natural range of these species.

  3. Production of anticandidal cotton textiles treated with oak gall extract

    Directory of Open Access Journals (Sweden)

    Ahmed A. Tayel

    Full Text Available Candida albicans, one of the most dreadful fungal pathogens threatening humans, could not be easily prevented. The anticandidal activity of oak gall extract, Quercus infectoria (QIE, was investigated as a potential natural alternative to synthetic and chemical fungicides. QIE anticandidal potentiality was confirmed using both qualitative and quantitative assays. Cotton textiles were treated with QIE and then evaluated as anticandidal fabrics. QIE-treated textiles had a potent anticandidal activity, which could completely inhibit the inoculated C. albicans cells. The durability of anticandidal activity in QIE-treated textiles almost completely disappeared after the fourth laundering cycle. QIE could be recommended, however, as a potent anticandidal agent for preparing antiseptic solutions and emulsions and as a finishing agent for manufacturing anticandidal disposable diapers and hygienic clothes.

  4. Production of anticandidal cotton textiles treated with oak gall extract.

    Science.gov (United States)

    Tayel, Ahmed A; El-Tras, Wael F; Abdel-Monem, Omnia A; El-Sabbagh, Sabha M; Alsohim, Abdullah S; El-Refai, Elham M

    2013-01-01

    Candida albicans, one of the most dreadful fungal pathogens threatening humans, could not be easily prevented. The anticandidal activity of oak gall extract, Quercus infectoria (QIE), was investigated as a potential natural alternative to synthetic and chemical fungicides. QIE anticandidal potentiality was confirmed using both qualitative and quantitative assays. Cotton textiles were treated with QIE and then evaluated as anticandidal fabrics. QIE-treated textiles had a potent anticandidal activity, which could completely inhibit the inoculated C. albicans cells. The durability of anticandidal activity in QIE-treated textiles almost completely disappeared after the fourth laundering cycle. QIE could be recommended, however, as a potent anticandidal agent for preparing antiseptic solutions and emulsions and as a finishing agent for manufacturing anticandidal disposable diapers and hygienic clothes.

  5. Analogue Electrical Circuit for Simulation of the Duffing-Holmes Equation

    DEFF Research Database (Denmark)

    Tamaseviciute, E.; Tamasevicius, A.; Mykolaitis, G.

    2008-01-01

    An extremely simple second order analogue electrical circuit for simulating the two-well Duffing-Holmes mathematical oscillator is described. Numerical results and analogue electrical simulations are illustrated with the snapshots of chaotic waveforms, phase portraits (Lissajous figures...

  6. Aerial Photography and Imagery, Ortho-Corrected - 2013 Digital Orthophotos - Holmes County

    Data.gov (United States)

    NSGIC Education | GIS Inventory — This dataset is a collection of GeoTIFF and MrSID format natural color orthophotos covering Holmes County, Florida. An orthophoto is remotely sensed image data in...

  7. Aerial Photography and Imagery, Ortho-Corrected - 2007 Digital Orthophotos - Holmes County

    Data.gov (United States)

    NSGIC Education | GIS Inventory — This dataset is a collection of GeoTIFF and MrSID format natural color orthophotos covering Washington, Holmes, and Bay County, Florida. An orthophoto is remotely...

  8. Aerial Photography and Imagery, Ortho-Corrected - 2012 Digital Orthophotos - Holmes County

    Data.gov (United States)

    NSGIC Education | GIS Inventory — This dataset is a collection of GeoTIFF and MrSID format natural color orthophotos covering Holmes and Washington County, Florida. An orthophoto is remotely sensed...

  9. Aerial Photography and Imagery, Ortho-Corrected - 2013 Digital Orthophotos - Holmes County

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This dataset is a collection of GeoTIFF and MrSID format natural color orthophotos covering Holmes County, Florida. An orthophoto is remotely sensed image data in...

  10. Aerial Photography and Imagery, Ortho-Corrected - 2009 Digital Orthophotos - Holmes County

    Data.gov (United States)

    NSGIC Education | GIS Inventory — This dataset is a collection of GeoTIFF and MrSID format natural color orthophotos covering Washington and Holmes County, Florida. An orthophoto is remotely sensed...

  11. Aerial Photography and Imagery, Ortho-Corrected - 2007 Digital Orthophotos - Holmes County

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This dataset is a collection of GeoTIFF and MrSID format natural color orthophotos covering Washington, Holmes, and Bay County, Florida. An orthophoto is remotely...

  12. On a Comparison and Contrast of Sherlock Holmes And Miss Jane Marple

    Institute of Scientific and Technical Information of China (English)

    张豪若

    2014-01-01

    In the history of detective stories, Sherlock Holmes and Miss Jane Marple remain as two of the most prominent fig-ures. Focusing on the two detectives' images, personality traits, detective strategies as well as settings of the stories, this study ex-amines the grounds that magnetize readers.The purpose of this research is to inquire into readers' orientations to Sherlock Holm-es and Miss Jane Marple, and to investigate the causes for their views. To fulfill that purpose, a questionnaire was designed and dis-tributed. Sherlock Holmes and Miss Jane Marple prove themselves to be successful detectives. Both of them have distinct images and personality traits as well as plausible detective strategies. The settings, combining reality with imagination, also play a dispens-able role. Besides, reasons given by students who disbelieve that they are real persons fail to convince.

  13. The Public, the Press, and Celebrities in The Return of Sherlock Holmes

    Directory of Open Access Journals (Sweden)

    Thomas Vranken

    2015-11-01

    Full Text Available Arthur Conan Doyle and his consulting detective had been famous for more than ten years when Doyle came to write The Return of Sherlock Holmes. In the following essay, I argue that this experience of fame shaped the composition of the third series of Holmes stories, in which the detective is resurrected a decade after going over the Reichenbach Falls. The essay approaches celebrity as a competitive interaction in which the public, the press, and the celebrity vie for control. It is argued that the stories in The Return of Sherlock Holmes work to empower the various celebrities that they portray – including not just Holmes but also well-known aristocrats, statesmen, scholars, and female ‘beauties’ – and to disempower their rival co-participants in the celebrity dynamic: the public and the press.

  14. Large drought-induced variations in oak leaf volatile organic compound emissions during PINOT NOIR 2012.

    Science.gov (United States)

    Geron, Chris; Daly, Ryan; Harley, Peter; Rasmussen, Rei; Seco, Roger; Guenther, Alex; Karl, Thomas; Gu, Lianhong

    2016-03-01

    Leaf-level isoprene and monoterpene emissions were collected and analyzed from five of the most abundant oak (Quercus) species in Central Missouri's Ozarks Region in 2012 during PINOT NOIR (Particle Investigations at a Northern Ozarks Tower - NOx, Oxidants, Isoprene Research). June measurements, prior to the onset of severe drought, showed isoprene emission rates and leaf temperature responses similar to those previously reported in the literature and used in Biogenic Volatile Organic Compound (BVOC) emission models. During the peak of the drought in August, isoprene emission rates were substantially reduced, and response to temperature was dramatically altered, especially for the species in the red oak subgenus (Erythrobalanus). Quercus stellata (in the white oak subgenus Leucobalanus), on the other hand, increased its isoprene emission rate during August, and showed no decline at high temperatures during June or August, consistent with its high tolerance to drought and adaptation to xeric sites at the prairie-deciduous forest interface. Mid-late October measurements were conducted after soil moisture recharge, but were affected by senescence and cooler temperatures. Isoprene emission rates were considerably lower from all species compared to June and August data. The large differences between the oaks in response to drought emphasizes the need to consider BVOC emissions at the species level instead of just the whole canopy. Monoterpene emissions from Quercus rubra in limited data were highest among the oaks studied, while monoterpene emissions from the other oak species were 80-95% lower and less than assumed in current BVOC emission models. Major monoterpenes from Q. rubra (and in ambient air) were p-cymene, α-pinene, β-pinene, d-limonene, γ-terpinene, β-ocimene (predominantly1,3,7-trans-β-ocimene, but also 1,3,6-trans-β-ocimene), tricyclene, α-terpinene, sabinene, terpinolene, and myrcene. Results are discussed in the context of canopy flux studies

  15. Land Change in Eastern Mediterranean Wood-Pasture Landscapes: The Case of Deciduous Oak Woodlands in Lesvos (Greece)

    Science.gov (United States)

    Schaich, Harald; Kizos, Thanasis; Schneider, Stefan; Plieninger, Tobias

    2015-07-01

    In Mediterranean Europe, wood-pasture landscapes with oak woodlands as emblematic ecosystems are undergoing rapid land-use change, which may threaten their legacy as hotspots of biodiversity, ecosystem services, and cultural heritage. The objective of this study was to quantify land cover changes and transitions as well as the dynamics of oak woodland patterns and densities over 50 years in two municipalities at the center and edges of Quercus macrolepis distribution in Northern Lesvos (Greece). We used aerial photographs from 1960 and WorldView-2 satellite images from 2010 to process land cover maps and metrics, and to calculate oak canopy cover with a point-grid sampling approach. Spatiotemporal dynamics of land cover change were generally high—especially between oak woodlands and grass- and shrub-lands, resulting in a more heterogeneous and fragmented landscape in 2010. Surprisingly, oak woodland area remained stable with marginal losses in one study site and gains in the other one. Oak canopy cover increased by 8 and 9 %. Spatial hotspots of change were mountainous and peripheral phrygana areas with expanding oak stands, as well as river valleys and near urban areas with expanding olive groves and grass- and shrublands in former complex cultivation and oak stands. We conclude that the parallel processes of abandonment of crop cultivation and intensification of livestock grazing have been less detrimental to oak woodlands than supposed. To ensure long-term persistence of oak woodlands in the face of ongoing rural depopulation and land-use intensification, environmental and agricultural policies should better address their specificities as anthropogenic habitats.

  16. The Great Detective, by Zach Dundas; Gender and the modern Sherlock Holmes, edited by Nadine Farghaly; and Sherlock Holmes, edited by Alex Werner [book review

    Directory of Open Access Journals (Sweden)

    Julia Knaus

    2017-03-01

    Full Text Available Review of: Zach Dundas. The Great Detective: The amazing rise and immortal life of Sherlock Holmes. Boston: Houghton Mifflin Harcourt, 2015, hardcover, $26 (336p, ISBN 978-0-544-21404-0, e-book $15.95 (2378 KB, ISBN 978-0-544-22020-1, ASIN B00LZ7GP6U. Nadine Farghaly, ed. Gender and the modern Sherlock Holmes: Essays on film and television adaptations since 2009. Jefferson, NC: McFarland, 2015, paperback, $35 (260p, ISBN 978-0-786-49459-0, e-book $9.99 (3353 KB, ISBN 978-1-4766-2281-1, ASIN B019WQQEY8. Alex Werner, ed. Sherlock Holmes: The man who never lived and will never die. London: Ebury Press, 2014, hardcover, £25 (256p, ISBN 978-0-09-195872-5, e-book £12.99, ISBN 978-1-47-350264-2.

  17. The Chemical Adventures of Sherlock Holmes: The Problem of Woolthshrap Prison

    Science.gov (United States)

    Rybolt, Thomas R.; Waddell, Thomas G.

    1995-12-01

    A story describing a chemical mystery with an emphasis on scientific observation and the criminal use of classic reaction of chemistry is related. This is the seventh article in a series presenting a scientific problem in mystery form in the context of the popular and beloved characters, Sherlock Holmes and Dr. Watson. There is a break in the story where the reader (students and teachers) can ponder and solve the mystery. Sherlock Holmes provides his solution in the paragraphs following this break.

  18. Variational derivation of two-component Camassa-Holm shallow water system

    CERN Document Server

    Ionescu-Kruse, Delia

    2012-01-01

    By a variational approach in the Lagrangian formalism, we derive the nonlinear integrable two-component Camassa-Holm system (1). We show that the two-component Camassa-Holm system (1) with the plus sign arises as an approximation to the Euler equations of hydrodynamics for propagation of irrotational shallow water waves over a flat bed. The Lagrangian used in the variational derivation is not a metric.

  19. Arthur Conan Doyle, Joseph Bell, and Sherlock Holmes. A neurologic connection.

    Science.gov (United States)

    Westmoreland, B F; Key, J D

    1991-03-01

    Neurologists, like physicians in several other medical specialties, can lay claim to Sherlock Holmes as one of their own. This assertion is validated by the number of neurologic conditions, such as seizures, stroke, syncope, encephalopathies, and head trauma, that are mentioned in the stories and novels. In addition, the article reviews the powers of observation and the deductive approach utilized by Conan Doyle and Joseph Bell, the models for Sherlock Holmes, and how these skills can be applied to medical problems.

  20. The Chemical Adventures of Sherlock Holmes: The Death Puzzle at 221B Baker Street

    Science.gov (United States)

    Rybolt, Thomas R.; Waddell, Thomas G.

    1999-04-01

    This story describes a chemical mystery with an emphasis on medicinal chemistry and qualitative analysis. It is the tenth article in a series presenting a scientific problem in mystery format in the context of the popular and beloved characters Sherlock Holmes and Dr. Watson. There is a break in the story where the reader (students and teachers) can ponder and solve the mystery. Sherlock Holmes then provides his solution.

  1. Headspace volatiles from 52 oak species advertise induction, species identity, and evolution, but not defense.

    Science.gov (United States)

    Pearse, Ian S; Gee, Wai S; Beck, John J

    2013-01-01

    Leaf volatiles convey information about a plant to other organisms in their proximity. Despite increasing interest in understanding the relevance of volatile emissions for particular ecological interactions, there has been relatively little effort to assess generally what information volatile profiles transmit. We surveyed the volatile profiles of wounded and unwounded leaves of 52 oak (Quercus) species. We used phylogenetic comparison and multivariate techniques to assess in what circumstances oak individuals advertised their species identity, evolutionary history, direct defenses, or damage. We found that both species identity and evolutionary history were advertised when leaves were wounded, but species could not be differentiated by odor when leaves were not wounded. Various fatty-acid derivative compounds showed the strongest phylogenetic signal suggesting that they may best disclose taxonomic affiliations in oaks. We tested whether oak volatile composition or diversity advertised high defensive investment, but we found no evidence for this. Wounded leaves disclose much about an oak species' identity and taxonomic affiliation, but unwounded leaves do not. This is consistent with the idea that volatile information is targeted toward natural enemy recruitment.

  2. Alternative strategies of seed predator escape by early-germinating oaks in Asia and North America.

    Science.gov (United States)

    Yi, Xianfeng; Yang, Yueqin; Curtis, Rachel; Bartlow, Andrew W; Agosta, Salvatore J; Steele, Michael A

    2012-03-01

    Early germination of white oaks is widely viewed as an evolutionary strategy to escape rodent predation; yet, the mechanism by which this is accomplished is poorly understood. We report that chestnut oak Quercus montana (CO) and white oak Q. alba (WO) (from North America), and oriental cork oak Q. variabilis (OO) and Mongolian oak Q. mongolica (MO) (from Asia) can escape predation and successfully establish from only taproots. During germination in autumn, cotyledonary petioles of acorns of CO and WO elongate and push the plumule out of the cotyledons, whereas OO and MO extend only the hypocotyls and retain the plumule within the cotyledons. Experiments showed that the pruned taproots (>6 cm) of CO and WO acorns containing the plumule successfully germinated and survived, and the pruned taproots (≥12 cm) of OO and MO acorns without the plumule successfully regenerated along with the detached acorns, thus producing two seedlings. We argue that these two distinct regeneration morphologies reflect alternative strategies for escaping seed predation.

  3. Bud burst and flowering phenology in a mixed oak forest from Eastern Romania

    Directory of Open Access Journals (Sweden)

    Ecaterina Nicoleta Chesnoiu

    2009-11-01

    Full Text Available Bud burst and flowering phenology have been observed in year 2008 ina natural white oak species complex situated in eastern Romania. A total of 300 mature individuals was mapped and identified based on leaf morphology. The community consists of four oak species: Quercus pedunculiflora, Q. robur, Q. pubescens and Q. petraea. A set of 28 individuals could not be unambiguously classified to one or another species. Data on bud burst showed a normal distribution and the differences among species were small. The "very late" flushing was recorded on 15th of April, three weeks later when compared to early flushing individuals. The time period between the bud burst and the complete development of leaves was nearly the same in all oak species, varying on average, between 18.4 and 20.6 days. The spatialdistribution of phenological groups within the complex appears to be non-randomly, because in many parts of the study plot exist groups in which most of the trees belong to the same phenological category. Our results indicate an overlap in flowering time for all oak species which occur in the area. The data support the hypothesis that interspecific gene flow is possible between closely related oak species.

  4. Bud burst and flowering phenology in a mixed oak forest from Eastern Romania

    Directory of Open Access Journals (Sweden)

    Ecaterina Nicoleta Chesnoiu

    2009-12-01

    Full Text Available Bud burst and flowering phenology have been observed in year 2008 in a natural white oak species complex situated in eastern Romania. A total of 300 mature individuals was mapped and identified based on leaf morphology. The community consists of four oak species: Quercus pedunculiflora, Q. robur, Q. pubescens and Q. petraea. A set of 28 individuals could not be unambiguously classified to one or another species. Data on bud burst showed a normal distribution and the differences among species were small. The "very late" flushing was recorded on 15th of April, three weeks later when compared to early flushing individuals. The time period between the bud burst and the complete development of leaves was nearly the same in all oak species, varying on average, between 18.4 and 20.6 days. The spatial distribution of phenological groups within the complex appears to be non-randomly, because in many parts of the study plot exist groups in which most of the trees belong to the same phenological category. Our results indicate an overlap in flowering time for all oak species which occur in the area. The data support the hypothesis that interspecific gene flow is possible between closely related oak species.

  5. Effects of site conditions and methods of cultivation on growth of sawtooth oak plantations

    Institute of Scientific and Technical Information of China (English)

    Luozhong TANG; Mukui YU; Dan ZHAO; Chunfeng YAN; Zhilong LIU; Shengzuo FANG

    2009-01-01

    The effects of site conditions and cultivation on the growth of sawtooth oak {Quercus acutissima Carr.) plantations were evaluated at the Hongyashan forest farm, in Chuzhou City, Anhui Province, China. The results indicate that the position on the slope, the amount of gravel and the thickness of the soil were important factors in the growth of the sawtooth oak. Lower slope positions with small amounts of gravel and a thick soil were better for the growth of this species than middle slope positions with more gravel and a thin soil. Given the site conditions of the hilly and mountainous areas in Chuzhou City, the mixed Chinese fir (Cunninghamia lanceolata Hook.) and sawtooth oak forests did not improve forest productivity compared with pure sawtooth oak forests. Both urea and compound fertilizers promoted the growth of sawtooth oak, as did site preparation and intercropping. Two years after planting, the height growth of ordinary seedlings with a starting height of 0.6 m was higher than that of supper seedlings with a starting height of 1.0 m. Compared with planting, the early growth of the coppices was faster, but the later growth of the coppices was slower.

  6. Post Sherlockian Times - Research into the Adaptations of the Novel Sherlock Holmes

    Institute of Scientific and Technical Information of China (English)

    YUAN Yu

    2015-01-01

    Sherlock Holmes, the literary image that Arthur Conan Doyle created in The Adventure of Sherlock Holmes, has undoubt⁃edly become an iconic figure of detective. For over a century, a number of films and TV series which based on this book are count⁃less, Sherlock Holmes has been brought to silver screen and stage for a million times. It will be mentioned Arthur Conan and Sher⁃lock Holmes in his book at first, and then review a list of Sherlock Holmes’adaptations in the history. Secondly, showing different personalities of this figure, taking film and TV dramas adaptation as examples to compare with the original novel ,from which we can discover different perspectives of this image of Sherlock Holmes. At last, it emphasizes through the ages, literary works have al⁃ways been materials for films and TV programs creation. From the everlasting image of Sherlock Holmes, we can see that literary spirits in classic masterpieces can be spread and flourished through adaptation of films and TV programs.

  7. Morphological characteristics and DNA sequence analysis of Petriella setifera and Oidiodendron setiferum from twigs of diseased oak

    Directory of Open Access Journals (Sweden)

    Hanna Kwaśna

    2014-08-01

    Full Text Available Examination of isolates of Petriella setifera and Oidiodendron setiferum revealed new diagnostic morphological charactcristics. Chlamydosporcs formed by P. setifera, isolated from twigs of sessile oak (Quercus petraea showing symptoms of oak decline, are described for the first time. The first pictures of P. setifera anamorphs since the publication of its original description in 1912 are presented. Isolates of O. setiferum, from sessile oak twigs and from a log of Scots pine (Pinus sylvestris, were found to have swollen, hyaline, thin-walled, sterile apices on the non-fertile hairs surrounding the fertile heads of conidiophores. They also had numerous coils formed by thin hyphae in the submerged mycelium in agar culture. The taxonomy of both fungi was confirmed by rDNA sequence analysis.

  8. Oak mortality associated with crown dieback and oak borer attack in the Ozark Highlands

    Science.gov (United States)

    Zhaofei Fan; John M. Kabrick; Martin A. Spetich; Stephen R. Shifley; Randy G. Jensen

    2008-01-01

    Oak decline and related mortality have periodically plagued upland oak–hickory forests, particularly oak species in the red oak group, across the Ozark Highlands of Missouri, Arkansas and Oklahoma since the late 1970s. Advanced tree age and periodic drought, as well as Armillaria root fungi and oak borer attack are believed to contribute to oak decline and mortality....

  9. Dendrochronological Investigations of Valonia Oak Trees in Western Greece

    Directory of Open Access Journals (Sweden)

    Andreas Papadopoulos

    2016-06-01

    Full Text Available Background and Purpose: Valonia oak (Quercus ithaburensis subsp. macrolepis (Kotschy Hedge & Yalt. is an east Mediterranean endemic, xerothermic and deciduous tree of particular interest in forestry. There has been a growing demand lately to include the species in reforestations in Greece which also increased the interest to investigate its response to climate change. The main purpose of this research is to study valonia oak from a dendrochronological – dendroclimatological point of view within its Mediterranean distribution range. Materials and Methods: Sampling took place in characteristic valonia oak stands where cross sections or tree-cores were taken from 40 trees. The cross sections and the tree-cores were prepared and cross-dated using standard dendrochronological methods and tree-ring widths were measured to the nearest 0.001 mm using the Windendro software program. The ARSTAN program was used to standardize the tree-ring data and to calculate dendrochronological statistical parameters. The inter-annual variability of tree-ring width and the radial growth trend were examined. Finally, tree-ring widths to climate relationships were calculated by orthogonal regression in combination with the bootstrap procedure using master residual chronology and monthly precipitation, temperature data and scPDSI drought index, from October of the n-1 year up to November of the n year. Results: The master chronology of valonia oak trees in Western Greece reaches 365 years, with an average ring width of 0.89 mm and with mean sensitivity being 0.21. The variation of the tree-ring widths indicates the influence of climate and human intervention in the past. Tree-ring to climate relationships show that valonia oak growth is positively affected by precipitations in January and March and by drought reduction during June and July. Conclusions: Valonia oak in Western Greece is a species of great interest for dendrochronological and dendroclimatological studies

  10. Variation of equilibrium moisture content of heat-treated Couratari oblongifolia, Fraxinus excelsior, and Quercus rubra wood

    Directory of Open Access Journals (Sweden)

    Qiaofang Zhou

    2013-02-01

    Full Text Available Heat treatment may result in variation of wood equilibrium moisture content (EMC. During this study, tauari (Couratari oblongifolia, ash (Fraxinus excelsior, and oak (Quercus rubra woods were heat-treated at 190, 200, and 210ºC for 3 hours and then put into a conditioning chamber with a temperature from 30 to 75ºC and a relative humidity from 50 to 90%. The isothermal moisture adsorption curve was subsequently analyzed. Results indicated that the EMC of heat-treated wood was reduced by 23.4 to 37.4% compared to non-treated wood, but the EMC difference at different heat-treated temperatures for three hardwoods was quite small and the EMC of heat-treated wood was inversely proportional to their dry density.

  11. Macromycetes of oak-lime-hornbeam woods in the Niepołomice Forest near Kraków (S Poland - monitoring studies

    Directory of Open Access Journals (Sweden)

    Władysława Wojewoda

    2014-08-01

    Full Text Available In the years 1994-1996 studies on macromycetes of the Niepołomice Forest near Kraków were made in four plots designated in deciduous forests (Tilio-Carpinetum stachyetosum with a population of Carpinus betulus, Quercus robur and Tilia cordata (the size of each plot was 1000 m2. The observations were made through an international project "Mycological monitoring in European oak forests". As many as 274 species were recorded, including 234 saprobic, 33 mycorrhizal, and 7 parasitic fungi. Moreover, 15 species of fungi are connected with oak, 24 species of fungi are threatened, and 16 species are new to Poland.

  12. Ability of chestnut oak to tolerate acorn pruning by rodents. The role of the cotyledonary petiole

    Science.gov (United States)

    Yi, Xianfeng; Curtis, Rachel; Bartlow, Andrew W.; Agosta, Salvatore J.; Steele, Michael A.

    2013-01-01

    Acorns of many white oak species germinate soon after autumn seed fall, a characteristic widely interpreted as a general adaptation to escape predation by small rodents. However, the mechanism by which early, rapid germination allows escape and/or tolerance of seed damage remains unclear. Here we reported how specific germination traits of chestnut oak ( Quercus montana) acorns, and those of other white oak species, allow successful escape from acorn pruning by rodents. During germination, chestnut oak acorns develop elongated cotyledonary petioles, which extend beyond the distal end of the acorn (1-2 cm) to the point at which the epicotyl and radicle diverge. However, granivorous rodents often prune the taproots above or below the plumule when eating or caching these germinated acorns in autumn. Hence, we hypothesized elongation of cotyledonary petioles allows chestnut oaks to escape acorn pruning by rodents. We simulated pruning by rodents by cutting the taproot at different stages of germination (radicle length) to evaluate the regeneration capacity of four resulting seedling remnants following taproot pruning: acorns with the plumule (remnant I), acorns without the plumule (remnant II), and pruned taproots with (remnant III) or without the plumule (remnant IV). Our results showed that remnant I germinated into seedlings regardless of the length of the taproot previously pruned and removed. Remnant III successfully germinated and survived provided that taproots were ≥6 cm in length, whereas remnant IV was unable to produce seedlings. Remnant II only developed adventitious roots near the severed ends of the cotyledonary petioles. Field experiments also showed that pruned taproots with the plumule successfully regenerated into seedlings. We suggest that the elongated cotyledonary petioles, typical of most white oak species in North America, represent a key adaptation that allows frequent escape from rodent damage and predation. The ability of pruned taproots to

  13. Lighting intensity of the soilsurface and restocking of oak groves

    Science.gov (United States)

    Slepykh, Victor; Zubko, Anna; Povolotckaia, Nina

    2016-04-01

    Oak groves of Caucasian Mineral Vody region (CMVR) possess a high ecological and balneological potential which defines the significance of their preservation and reproduction [1]. The role assessment of lighting intensity on renewal of oak groves was carried out on four trial squares (ts) in natural sixty-seven years old forest stand with prevalence of English oak (Quercus robur L.) with unimodal sity (type of the habitat - C1). The illumination was measured at the grass level by the universal measuring instrument of meteoparameters ATT-9508 with an illumination sensor of ATA-1591. The assessment of reforestation was carried out according to the established standards [2]. In the winter of 2005 there was conducted a selecting cutting cabin of the forest stand according to a local method on ts2 with intensity 30%, on ts4 - 50% after which the illumination on the soil surface in relation to illumination of an open place in the summer of 2005 increased from 4.9% to 33.9% on ts2, and from 5.9% to 24.4% on ts4. But by 2014 the illumination decreased till 3.0% on ts2, till 5.4% on ts4 because of an intensive soil grassing down. The control was carried out by ts1 and ts3 on which from 2005 to 2014 the illumination of the soil surface decreased from 4 to 2% as a result of the development of all storeys. As a result due to an intensive soil grassing-down, the total quantity of young oak trees decreased from 2005 to 2014 from 25.6 thousand pcs/ha to 5.9 thousand pcs/ha on ts2; on from 17.3 thousand pcs/ha to 4.0 thousand pcs/ha on ts4. At the same time the total quantity of young oak trees on control squares increased respectively for 1.4% (from 18.8 thousand pcs/ha to 19.1 thousand pcs/ha) on ts1, for 38.7% (from 25.2 thousand pcs/ha to 41.1 thousand pcs/ha). The experiment showed that small young oak trees perishes in the first years of their life from a lack of light and competition from grasland vegetation without providing successful reforestation. Conclusion. So it is

  14. Variations in Quercus sp. pollen seasons (1996-2011) in Poznań, Poland, in relation to meteorological parameters.

    Science.gov (United States)

    Grewling, Lukasz; Jackowiak, Bogdan; Smith, Matt

    2014-01-01

    The aim of this study is to supply detailed information about oak (Quercus sp.) pollen seasons in Poznań, Poland, based on a 16-year aerobiological data series (1996-2011). The pollen data were collected using a volumetric spore trap of the Hirst design located in Poznań city center. The limits of the pollen seasons were calculated using the 95 % method. The influence of meteorological parameters on temporal variations in airborne pollen was examined using correlation analysis. Start and end dates of oak pollen seasons in Poznań varied markedly from year-to-year (14 and 17 days, respectively). Most of the pollen grains (around 75 % of the seasonal pollen index) were recorded within the first 2 weeks of the pollen season. The tenfold variation was observed between the least and the most intensive pollen seasons. These fluctuations were significantly related to the variation in the sum of rain during the period second fortnight of March to first fortnight of April the year before pollination (r = 0.799; p < 0.001). During the analyzing period, a significant advance in oak pollen season start dates was observed (-0.55 day/year; p = 0.021), which was linked with an increase in the mean temperature during the second half of March and first half of April (+0.2 °C; p = 0.014). Daily average oak pollen counts correlated positively with mean and maximum daily temperatures, and negatively with daily rainfall and daily mean relative humidity.

  15. Evaluation of wildlife-habitat relationships data base for predicting bird community composition in central California chaparral and blue oak woodlands

    Science.gov (United States)

    Avery, M.L.; van Riper, Charles

    1990-01-01

    The California Wildlife-Habitat Relationships (WHR) database can be used to assist resource managers to evaluate effects of habitat manipulations on wildlife. The accuracy of predictions from WHR was evaluated using data from bird surveys conducted during winter and spring 1984 and 1985 in chamise (Adenostema fasciculata) chaparral, mixed chaparral and blue oak (Quercus douglasii) woodland. Considerable variability between habitat types was found for errors both of commission and of omission.

  16. Macromycetes of oak forests in the Jurassic Landscape Park (Częstochowa Upland - monitoring studies

    Directory of Open Access Journals (Sweden)

    Maria Ławrynowicz

    2014-08-01

    Full Text Available Mycological observations were carried out between 1994-1996 in two representative plots (1000 m2 each in 80-year-old oak plantation (Quercus robur and Qu. petraea on calcareous hill in the Mstów village in the Jurassic Landscape Park. The project was carried out in the frame of international network of the „Mycological monitoring in European oak forests". During 24 visits in the plots a total of 190 species of macromycetes was recorded: 80 mycorrhizal and 110 saprobic fungi. Among them 2 species are new to Poland and 16 are inscribed in the Red List of threatened macromycetes in Poland (Wojewoda and Ławrynowicz 1992.

  17. Soil CO2 Efflux in a Mixed Pine-Oak Forest in Valsaín (Central Spain

    Directory of Open Access Journals (Sweden)

    Rosa Inclán

    2007-01-01

    Full Text Available Soil-surface CO2 efflux and its spatial and temporal variation were investigated in a southern Mediterranean, mixed pine-oak forest ecosystem on the northern slopes of the Sierra de Guadarrama in Spain from February 2006 to July 2006. Measurements of soil CO2 efflux, soil temperatures, and moisture were conducted in nine 1963-m2 sampling plots distributed in a gradient around the ecotone between Pinus sylvestris L. and Quercus pyrenaica Lam. forest stands. Total soil organic matter, Walkey-Black C, particulate organic matter, organic matter fraction below 53 μm, total soil nitrogen content, total soil organic carbon content, and pH were also measured under three representative mature oak, pine, and mixed pine-oak forest stands. Soil respiration showed a typical seasonal pattern with minimums in winter and summer, and maximums in spring, more pronounced in oak and oak-pine stands. Soil respiration values were highest in pine stands during winter and in oak stands during spring and summer.

  18. Lingering grains of truth around comet 17P/HOLMES

    Energy Technology Data Exchange (ETDEWEB)

    Stevenson, R.; Bauer, J. M.; Mainzer, A. K.; Masiero, J. R. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, MS 183-427, Pasadena, CA 91109 (United States); Kramer, E. A. [Department of Physics, University of Central Florida, 4000 Central Florida Blvd, Orlando, FL 32816 (United States); Grav, T., E-mail: Rachel.A.Stevenson@jpl.nasa.gov [Planetary Science Institute, 1700 East Fort Lowell, Suite 106, Tucson, AZ 85719-2395 (United States)

    2014-06-01

    Comet 17P/Holmes underwent a massive outburst in 2007 October, brightening by a factor of almost a million in under 48 hr. We used infrared images taken by the Wide-Field Infrared Survey Explorer mission to characterize the comet as it appeared at a heliocentric distance of 5.1 AU almost 3 yr after the outburst. The comet appeared to be active with a coma and dust trail along the orbital plane. We constrained the diameter, albedo, and beaming parameter of the nucleus to 4.135 ± 0.610 km, 0.03 ± 0.01, and 1.03 ± 0.21, respectively. The properties of the nucleus are consistent with those of other Jupiter family comets. The best-fit temperature of the coma was 134 ± 11 K, slightly higher than the blackbody temperature at that heliocentric distance. Using Finson-Probstein modeling, we found that the morphology of the trail was consistent with ejection during the 2007 outburst and was made up of dust grains between 250 μm and a few cm in radius. The trail mass was ∼1.2-5.3 × 10{sup 10} kg.

  19. Luke May of Seattle--"America's Sherlock Holmes".

    Science.gov (United States)

    Beck, J

    1992-01-01

    This paper provides a brief biography of Luke S. May (1886-1965), whose pioneering work in forensic science in the United States has not received full recognition. May began as a private detective in Salt Lake City, Utah, shortly after the turn of the century and later established his own agency, the Revelare International Secret Service, which he moved to Seattle, Washington, in 1919. Although basically self-taught in scientific matters, May built a solid reputation among police agencies and attorneys in the Pacific Northwest and Western Canada as a serious and effective scientific investigator in the era before public crime laboratories. This reputation as "America's Sherlock Holmes" also led to his being consulted on the establishment of the first American crime laboratory at Northwestern University in Chicago, Illinois, and on a laboratory for the Royal Canadian Mounted Police at Regina, in Saskatchewan, Canada. He contributed to a landmark case of court acceptance of toolmark identification, invented specialized instruments, and founded an institute to teach scientific criminal investigation to police officers. His earliest associates were John L. Harris and J. Clark Sellers, both of whom became recognized document examiners on the West Coast and were followed by a second and a third generation of practitioners.

  20. Sherlock Holmes and the case of the plagiarised paper.

    Science.gov (United States)

    Kennedy, David

    2011-07-01

    Narrative pedagogy has the power to explore issues in a way that expository teaching cannot match. Moon and Fowler (2008, p.236), for example, point out that fiction has much to offer in focusing creatively on issues, exploring subtleties and discussing related emotional dynamics. But they comment that in nurse education fiction is 'a relatively untapped' (though valuable) resource for teaching. 'Sherlock Holmes and the Case of the Plagiarised Paper' is a fictional account that responds to Moon and Fowler's challenge. It explores a controversial issue--student plagiarism. The narrative sets the discussion in a fictional context--an interaction between fictional characters and a real character. It explores difficulties that novice writers have in avoiding plagiarism. It debates how teachers may respond to student plagiarism. It contextualises student plagiarism in the wider world of academic plagiarism. Its purpose is to enable the reader to identify and act on these issues in a way that an expository examination of student plagiarism could not achieve. In response to suggestions from reviewers, the article has an Appendix which outlines some of the issues and techniques associated with the use of fiction in nursing education.