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Sample records for nothofagus betuloides mirb

  1. Caracterización de suelos bajo bosques de Nothofagus betuloides (Mirb Blume, en Tierra del Fuego, Chile Characterization of soils of Nothofagus betuloides (Mirb Blume forests, in Tierra del Fuego, Chile

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    VÍCTOR GERDING

    2002-12-01

    Full Text Available En tres sectores de la parte occidental de Tierra del Fuego (54º45'-54º15' S, 68º40'-70º10' O se caracterizó morfológica, física y químicamente los suelos bajo bosques de coigüe de Magallanes (Nothofagus betuloides (Mirb Blume y sus especies asociadas lenga (Nothofagus pumilio (P. et E. Krasser y canelo (Drimys winteri Forst.. Se describieron 85 perfiles de suelo y aproximadamente 250 observaciones con bastón pedológico. Los suelos bajo coigüe de Magallanes eran jóvenes, muy influidos por la actividad volcánica, topografía y clima. Se observó la presencia de los órdenes Spodosol e Iceptisol, principalmente. En general los suelos eran delgados a muy delgados (mayoritariamente entre 10 y 40 cm, con un alto volumen de esqueleto, textura franca, estructura masiva a granular, capacidad de agua aprovechable baja y drenaje externo e interno moderado a lento. Además, presentan una alta acidez (pH 4-5,5, una baja oferta nutricional y muy altos niveles de saturación de aluminio (promedio > 60 %. El mantillo (Oe/Oa presentó condiciones adecuadas para el desarrollo radicular. Existe comúnmente un horizonte blanco (frecuentemente 10 YR 5/1-2 inmediatamente debajo del mantillo, con textura franco limosa y estructura masiva, con arraigamiento muy bajo. Se plantea como hipótesis que este horizonte se originó por depósitos de cenizas volcánicas y procesos de podzolización. Se concluye que la fertilidad de estos suelos es baja debido a limitantes físicas (dificultades de arraigamiento y químicas (acidez, toxicidad de aluminio, baja oferta de basesSoils under coigüe de Magallanes (Nothofagus betuloides (Mirb Blume forests, located in the oriental part of Tierra del Fuego (54º45'-54º15' S, 68º40'-70º10' W, were characterized morphologically, physically and chemically. Associated tree species were lenga (Nothofagus pumilio (P. et E. Krasser and canelo (Drimys winterii Forst.. A total of 85 soil profiles and approximately 250 soil

  2. Aplicación de relaciones de densidad-diámetro y de área potencial aprovechable en bosques de Nothofagus Dombeyi (mirb.) Oerst, como herramientas de planificación silvícola .

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    Cruz Johnson, Pablo Christian

    2013-01-01

    Uno de los objetivos de esta tesis de doctorado fue analizar la aplicación de relaciones de densidad ¿ diámetro en bosques de Nothofagus dombeyi (Mirb.) oerst, para la localidad del Río Mirta en la XI Región de Chile, como herramientas de planificación silvícola. El método de análisis consistió en la generación de una muestra de densidad¿diámetro a partir de la que se determinó el índice de densidad máximo (IDmax) a partir del cual se estimaron las máximas densidades que la especie podría alc...

  3. Mineralización del nitrógeno, carbono y actividad enzimática del suelo en un bosque de Nothofagus obliqua (Mirb Oerst y una plantación de Pinus radiata D. Don. del centro-sur de Chile Nitrogen and carbon mineralization and enzyme activity in soils of Nothofagus obliqua (Mirb Oerst stands and Pinus radiata D. Don plantation in south-central Chile

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    YESSICA RIVAS

    2009-03-01

    Full Text Available En Chile, el establecimiento de plantaciones comerciales de rápido crecimiento ha sido sostenido en las últimas décadas mediante la sustitución de bosques nativos y conversión de suelos agrícolas. Pinus radiata D. Don es la principal especie productiva, debido a su crecimiento acelerado y adaptabilidad al clima y los suelos. En el presente estudio se plantea que la actividad biológica del suelo es variable a través del año, en respuesta a variaciones de precipitación, temperatura y contenido de humedad de suelo y que el cambio de uso de suelo desde un bosque templado de Nothofagus obliqua (Mirb Oerst a una plantación con coniferas exóticas, modifica la química del suelo y consecuentemente los procesos de N-min, C-min y la actividad biológica del suelo. Esta hipótesis fue examinada en un bosque de N. obliqua y una plantación de P. radiata del centro-sur de Chile (40°07' S, 72° O. Se evaluó mensualmente la tasa mineralización de nitrógeno (N-min, cabono (C-min y la actividad enzimática potencial del suelo (ureasa, proteasa e hidrólisis de la fluoresceína diacetato entre septiembre 2003 y mayo 2005. Los resultados demuestran que los niveles de las variables de actividad biológica del suelo fueron significativamente diferentes entre las parcelas de bosque y plantación (Lambda de Wilk = 0,022; F 5,80 = 733; P In Chile, commercial forests plantations have increased during the last decades due in part to replacement of native forests and conversion of agricultural soils. Pinus radiata D. Don has been the main tree planted, due to its rapid growth and adaptability. In the present study we proposed that biological activity varies along the year due to changes of precipitation, temperature and soil water content and mainly because the conversion of native forest to exotic P. radiata plantations alters the soil chemistry, N and C mineralization and the potential enzymatic activity in these soils. This hypothesis was examined in a

  4. Effect of ectomycorrhizal colonization and drought on reactive oxygen species metabolism of Nothofagus dombeyi roots.

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    Alvarez, Maricel; Huygens, Dries; Fernandez, Carlos; Gacitúa, Yessy; Olivares, Erick; Saavedra, Isabel; Alberdi, Miren; Valenzuela, Eduardo

    2009-08-01

    Infection with ectomycorrhizal fungi can increase the ability of plants to resist drought stress through morphophysiological and biochemical mechanisms. However, the metabolism of antioxidative enzyme activities in the ectomycorrhizal symbiosis remains poorly understood. This study investigated biomass production, reactive oxygen metabolism (hydrogen peroxide and malondialdehyde concentration) and antioxidant enzyme activity (superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase) in pure cultures of the ectomycorrhizal fungi Descolea antartica Sing. and Pisolithus tinctorius (Pers.) Coker & Couch, and non-mycorrhizal and mycorrhizal roots of Nothofagus dombeyi (Mirb.) roots under well-watered conditions and drought conditions (DC). The studied ectomycorrhizal fungi regulated their antioxidative enzyme metabolism differentially in response to drought, resulting in cellular damage in D. antartica but not in P. tinctorius. Ectomycorrhizal inoculation and water treatment had a significant effect on all parameters studied, including relative water content of the plant. As such, N. dombeyi plants in symbiosis experienced a lower oxidative stress effect than non-mycorrhizal plants under DC. Additionally, ectomycorrhizal N. dombeyi roots showed a greater antioxidant enzyme activity relative to non-mycorrhizal roots, an effect which was further expressed under DC. The association between the non-specific P. tinctorius and N. dombeyi had a more effective reactive oxygen species (ROS) metabolism than the specific D. antartica-N. dombeyi symbiosis. We conclude that the combination of effective ROS prevention and ROS detoxification by ectomycorrhizal plants resulted in reduced cellular damage and increased plant growth relative to non-mycorrhizal plants under drought.

  5. Establishment of a Nothofagus alessandrii plantation using different ...

    African Journals Online (AJOL)

    There is a lack of information regarding the establishment of Nothofagus alessandrii plantations, including any impacts that shading and weed control may have on early survival and growth. A trial was therefore initiated where four shade levels (0% and Rachel® plastic net of 50%, 65%, and 80%) and two weed control ...

  6. Tree dynamics in canopy gaps in old-growth forests of Nothofagus pumilio in Southern Chile

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    Fajardo, Alex; Graaf, de N.R.

    2004-01-01

    The gap dynamics of two Nothofagus pumilio (lenga) stands have been investigated. We evaluated and compared tree diameter distributions, spatial patterns, tree fall and gap characteristics and regeneration responses in gaps in two old-growth forests of Nothofagus pumilio in Southern Chile

  7. Ectomycorrhizal fungi enhance nitrogen and phosphorus nutrition of Nothofagus dombeyi under drought conditions by regulating assimilative enzyme activities.

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    Alvarez, Maricel; Huygens, Dries; Olivares, Erick; Saavedra, Isabel; Alberdi, Miren; Valenzuela, Eduardo

    2009-08-01

    Drought stress conditions (DC) reduce plant growth and nutrition, restraining the sustainable reestablishment of Nothofagus dombeyi in temperate south Chilean forest ecosystems. Ectomycorrhizal symbioses have been documented to enhance plant nitrogen (N) and phosphorus (P) uptake under drought, but the regulation of involved assimilative enzymes remains unclear. We studied 1-year-old N. dombeyi (Mirb.) Oerst. plants in association with the ectomycorrhizal fungi Pisolithus tinctorius (Pers.) Coker & Couch. and Descolea antartica Sing. In greenhouse experiments, shoot and root dry weights, mycorrhizal colonization, foliar N and P concentrations, and root enzyme activities [glutamate synthase (glutamine oxoglutarate aminotransferase (GOGAT), EC 1.4.1.13-14), glutamine synthetase (GS, EC 6.3.1.2), glutamate dehydrogenase (GDH, EC 1.4.1.2-4), nitrate reductase (NR, EC 1.6.6.1), and acid phosphomonoesterase (PME, EC 3.1.3.1-2)] were determined as a function of soil-water content. Inoculation of N. dombeyi with P. tinctorius and D. antartica significantly stimulated plant growth and increased plant foliar N and P concentrations, especially under DC. Ectomycorrhizal inoculation increased the activity of all studied enzymes relative to non-mycorrhizal plants under drought. We speculate that GDH is a key enzyme involved in the enhancement of ectomycorrhizal carbon (C) availability by fuelling the tricarboxylic acid (TCA) cycle under conditions of drought-induced carbon deficit. All studied assimilative enzymes of the ectomycorrhizal associations, involved in C, N, and P transfers, are closely interlinked and interdependent. The up-regulation of assimilative enzyme activities by ectomycorrhizal fungal root colonizers acts as a functional mechanism to increase seedling endurance to drought. We insist upon incorporating ectomycorrhizal inoculation in existing Chilean afforestation programs.

  8. Estimación del índice de sitio en rodales de Nothofagus dombeyi a través de herramientas de teledetección espacial

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    C. Esse

    2013-12-01

    Full Text Available La estimación del índice de sitio y la calidad del sitio constituyen herramientas básicas en la gestión de los ecosistemas forestales y la práctica de la silvicultura. El estudio de la distribución espacial y la dinámica temporal de índice de sitio y la calidad del sitio de los ecosistemas forestales aún carece de los avances tecnológicos. Este estudio propone la integración de las herramientas de teledetección para la estimación de la productividad forestal para áreas remotas. Se evaluó el potencial de aplicación de la metodología en amplias regiones y los bosques con la evaluación de la exactitud. Los resultados muestran que el índice del sitio de los bosques secundarios de Nothofagus dombeyi (Mirb. Oerst., están en correlación lineal con los índices de vegetación normalizada (NDVI, índice de diferencia de vegetación ajustado (TNDVI, banda Infrarroja pura de la imagen y transformación de componentes principales. Este estudio demostró que este enfoque puede ser utilizado en la estimación de la productividad de bosques secundarios en diferentes ecosistemas forestales.

  9. Potential biotechnological application of mycorrhizas and yeasts associated with Nothofagus nervosa (Rauli)

    International Nuclear Information System (INIS)

    Fernandez, N.; Fontenla, S.; Gallo, L.; Marchelli, P.

    2009-01-01

    Nothofagus nervosa is an ecologically and economically important species of south American temperate forests. In Argentina, it has a reduced natural distribution area due to over exploitation, overgrazing and forest fires. This critical situation led to the implementation of conservation and domestication programs. (Author)

  10. Guanaco’s diet and forage preferences in Nothofagus forest environments of Tierra del Fuego, Argentina

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    Quinteros, C.P.; Bava, J.; Gobbi, M.E.; Defossé, G.E.

    2017-11-01

    Aim of study: Guanaco (Lama guanicoe Müller), is a South American native ungulate widely distributed in Patagonia, which in the island of Tierra del Fuego (TF), extends its habitat into Nothofagus spp. forests. Within these forests, guanacos consume lenga (Nothofagus pumilio) leaves and twigs, and other understory species. The aim of this work was to determine: 1) the spring and summer diet of free ranging guanacos, and 2) which plants, grown in the forest understory, guanacos do prefer, or avoid, in these seasons of great forage abundance. Area of study: Tierra del Fuego (Argentina), on three representative areas which combined Nothofagus forests and adjacent meadows (vegas). Material and Methods: uanacos’ diet was determined by comparing epidermal and non-epidermal plant fragments with micro-histological analyses of feces. The analysis was made from composite samples of fresh feces, collected at the seasons of maximum forage productivity (spring and summer). Main results: During spring, 48% of guanacos’ diet was composed of lenga leaves, 30% of grass-like species, 15% of grasses, and less than 7% of herbs, shrubs, and lichens. In summer, 40% of the diet was composed of grasses, 30% of lenga leaves, 25% of grass-like species and the rest corresponded to herbs, shrubs, and lichens. Within the forest understory, guanaco selected lenga leaves and twigs, grass species were consumed according to their availability (or sometimes rejected), while other herbs were not consumed at all. Research highlights: Guanacos’ consumption preference for lenga, even considering the high availability of other forages, could adversely affect forest regeneration.

  11. Guanaco’s diet and forage preferences in Nothofagus forest environments of Tierra del Fuego, Argentina

    International Nuclear Information System (INIS)

    Quinteros, C.P.; Bava, J.; Gobbi, M.E.; Defossé, G.E.

    2017-01-01

    Aim of study: Guanaco (Lama guanicoe Müller), is a South American native ungulate widely distributed in Patagonia, which in the island of Tierra del Fuego (TF), extends its habitat into Nothofagus spp. forests. Within these forests, guanacos consume lenga (Nothofagus pumilio) leaves and twigs, and other understory species. The aim of this work was to determine: 1) the spring and summer diet of free ranging guanacos, and 2) which plants, grown in the forest understory, guanacos do prefer, or avoid, in these seasons of great forage abundance. Area of study: Tierra del Fuego (Argentina), on three representative areas which combined Nothofagus forests and adjacent meadows (vegas). Material and Methods: uanacos’ diet was determined by comparing epidermal and non-epidermal plant fragments with micro-histological analyses of feces. The analysis was made from composite samples of fresh feces, collected at the seasons of maximum forage productivity (spring and summer). Main results: During spring, 48% of guanacos’ diet was composed of lenga leaves, 30% of grass-like species, 15% of grasses, and less than 7% of herbs, shrubs, and lichens. In summer, 40% of the diet was composed of grasses, 30% of lenga leaves, 25% of grass-like species and the rest corresponded to herbs, shrubs, and lichens. Within the forest understory, guanaco selected lenga leaves and twigs, grass species were consumed according to their availability (or sometimes rejected), while other herbs were not consumed at all. Research highlights: Guanacos’ consumption preference for lenga, even considering the high availability of other forages, could adversely affect forest regeneration.

  12. Seasonal variation and enzymatic potential of microfungi associated with the decomposition of Nothofagus pumilio leaf litter

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    VALENZUELA, EDUARDO; LEIVA, SERGIO; GODOY, ROBERTO

    2001-01-01

    Se estudió la variación estacional y el potencial enzimático de microhongos aislados desde el follaje y hojarasca de Nothofagus pumilio sometida a degradación natural durante 1 año. La investigación se realizó en un bosque de N. pumilio ubicado en una microcuenca del Valle de Antillanca, Parque Nacional Puyehue (40° 47' S, 72° 12' O, 1.120 m de altitud). Hojas senescentes colectadas desde árboles de N. pumilio se depositaron en bolsas de malla de nylon ("litter bags") y se sometieron a degrad...

  13. VOLUME AND TAPER EQUATIONS FOR COMMERCIAL STEMS OF Nothofagus obliqua AND N. alpina

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    Hernan Attis Beltran

    2017-09-01

    Full Text Available Timber volume of standing trees is essential information for management decisions. The increasing need to optimize the potential capacity of forests maintaining their conservation, requires the quantification of the different potential possible timber products. The aim was to adjust taper equations to determine volumes of different timber products for commercial stems of Nothofagus alpina and N. obliqua. Trees of both species were randomly selected in harvesting areas of Lanin National Park (Argentina. Trees were felled and cut into commercial logs, measuring diameter with bark at different heights up to the beginning of the crown, and for each tree the diameter at breast height and total height. Five taper equations were selected and non-linear regression processes were employed for the fittings. We obtained the volume through the integration of the stem profile equation and the rotation in the space thereof through solid of revolution. The Bennet and Swindel (1972 model was selected for both Nothofagus species, obtaining similar equation parameters and differences were observed at the top of the stems of larger trees. For this the use of an integrated model is not recommended. With the obtained equations it is possible to: (i estimatevolume at different heights and for different commercial diameters, and (ii predict the height at which both species reach to a certain diameter. The model presented some statistical limitations (e.g. multicollinearity, however, the fitting of the equation and the easy understanding of the outputs support it as a useful tool in a broad range of forest applications.

  14. Variaciones Intra-Específicas en el crecimiento primario de Nothofagus dombeyi (Nothofagaceae Intra-specific variations in the primary growth of Nothofagus dombeyi (Nothofagaceae

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    Javier Puntieri

    2005-07-01

    Full Text Available Se evaluó el patrón de crecimiento bajo condiciones controladas de los ejes foliados de 16 plántulas de Nothofagus dombeyi. Los individuos fueron ubicados en una cámara de crecimiento y se evaluó el crecimiento del tronco en dos eventos de crecimiento sucesivos (julio 2002 - marzo 2004. Se identificaron tres patrones de crecimiento del primer brote medido: (1 crecimiento ininterrumpido por unos 8 meses, (2 crecimiento interrumpido por un período de reposo no menor de 7 semanas, con rebrote posterior y (3 crecimiento ininterrumpido por 6 a 7 meses. En los individuos con los patrones de crecimiento 1 y 2, la tasa máxima de producción de hojas del primer brote producido fue mayor que en los individuos con el tercer patrón de crecimiento. La tasa media de crecimiento fue mayor para los brotes del primer grupo que para los de los otros dos grupos. El segundo de los brotes medidos se alargó en un único pulso y alcanzó menor tamaño que el primero de los brotes. Se discute el posible rol de gradientes ontogenéticos o de variaciones genéticas entre individuos de coihue como explicación de los diferentes patrones de crecimiento registrados.

  15. Transcriptome survey of Patagonian southern beech Nothofagus nervosa (= N. Alpina: assembly, annotation and molecular marker discovery

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    Torales Susana L

    2012-07-01

    Full Text Available Abstract Background Nothofagus nervosa is one of the most emblematic native tree species of Patagonian temperate forests. Here, the shotgun RNA-sequencing (RNA-Seq of the transcriptome of N. nervosa, including de novo assembly, functional annotation, and in silico discovery of potential molecular markers to support population and associations genetic studies, are described. Results Pyrosequencing of a young leaf cDNA library generated a total of 111,814 high quality reads, with an average length of 447 bp. De novo assembly using Newbler resulted into 3,005 tentative isotigs (including alternative transcripts. The non-assembled sequences (singletons were clustered with CD-HIT-454 to identify natural and artificial duplicates from pyrosequencing reads, leading to 21,881 unique singletons. 15,497 out of 24,886 non-redundant sequences or unigenes, were successfully annotated against a plant protein database. A substantial number of simple sequence repeat markers (SSRs were discovered in the assembled and annotated sequences. More than 40% of the SSR sequences were inside ORF sequences. To confirm the validity of these predicted markers, a subset of 73 SSRs selected through functional annotation evidences were successfully amplified from six seedlings DNA samples, being 14 polymorphic. Conclusions This paper is the first report that shows a highly precise representation of the mRNAs diversity present in young leaves of a native South American tree, N. nervosa, as well as its in silico deduced putative functionality. The reported Nothofagus transcriptome sequences represent a unique resource for genetic studies and provide a tool to discover genes of interest and genetic markers that will greatly aid questions involving evolution, ecology, and conservation using genetic and genomic approaches in the genus.

  16. Mistletoes and epiphytic lichens contribute to litter input in Nothofagus antarctica forests

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    Soler, Rosina; Pastur, Guillermo Martínez; Lencinas, María Vanessa; Peri, Pablo Luis

    2015-10-01

    Litter input is one of the key components that define nutrient cycling in forests and the majority of studies only consider the tree components of litterfall. However, epiphytic species can play a crucial role in litter input throughout the growing season. This work evaluates changes in litter production by mistletoe (Misodendrum sp.) and epiphytic lichen (Usnea sp.), related to crown cover in mature unmanaged, second-growth and managed (thinned for silvopastoral use) forests in Tierra del Fuego (Argentina). We used plastic traps to collect litterfall biomass from trees, lichens and mistletoes on a monthly basis over three consecutive years. Tree litter was considerable during autumn (March to May), which is typical of Nothofagus deciduous species in the Southern hemisphere. In contrast, peak litterfall from mistletoes and lichens occurred during spring and summer seasons. Tree litter (1954-3398 kg dry matter ha-1 year-1) was correlated with crown cover gradient being highest in second-growth forests and lowest in thinned sites. While litter input from mistletoes did not vary among forest types (307-333 kg dry matter ha-1 year-1), lichen litter (11-40 kg dry matter ha-1 year-1) was higher in unmanaged and thinned mature forests despite differences in tree crown cover. Contrary to what we expected, the management practices investigated here did not affect the biomass of canopy communities compared to unmanaged mature forests. Mistletoes and lichens significantly increased the spatial (forest type) and temporal complexity (extended period of falling) of litterfall in Nothofagus antarctica forests. This study provides a starting point to understand the ecological relevance of canopy communities in the Patagonian forests of southern Argentina.

  17. Seed dormancy responses to temperature relate to Nothofagus species distribution and determine temporal patterns of germination across altitudes in Patagonia.

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    Arana, María V; Gonzalez-Polo, Marina; Martinez-Meier, Alejandro; Gallo, Leonardo A; Benech-Arnold, Roberto L; Sánchez, Rodolfo A; Batlla, Diego

    2016-01-01

    Seeds integrate environmental cues that modulate their dormancy and germination. Although many mechanisms have been identified in laboratory experiments, their contribution to germination dynamics in existing communities and their involvement in defining species habitats remain elusive. By coupling mathematical models with ecological data we investigated the contribution of seed temperature responses to the dynamics of germination of three Nothofagus species that are sharply distributed across different altitudes in the Patagonian Andes. Seed responsiveness to temperature of the three Nothofagus species was linked to the thermal characteristics of their preferred ecological niche. In their natural distribution range, there was overlap in the timing of germination of the species, which was restricted to mid-spring. By contrast, outside their species distribution range, germination was temporally uncoupled with altitude. This phenomenon was described mathematically by the interplay between interspecific differences in seed population thermal parameters and the range in soil thermic environments across different altitudes. The observed interspecific variations in seed responsiveness to temperature and its environmental regulation, constitute a major determinant of the dynamics of Nothofagus germination across elevations. This phenomenon likely contributes to the maintenance of patterns of species abundance across altitude by placing germinated seeds in a favorable environment for plant growth. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  18. Xanthophyllomyces dendrorhous (Phaffia rhodozyma on stromata of Cyttaria hariotii in northwestern Patagonian Nothofagus forests

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    Diego Libkind

    2011-09-01

    Full Text Available The occurrence and distribution of Xanthophyllomyces dendrorhous associated with Cyttaria hariotii parasitizing three Nothofagus species (N. dombeyi, N. antarctica and N. pumilio in northwestern Patagonia (Argentina, as well as the factors that may affect this distribution were herein studied. Between 2000 and 2007, samples were obtained from 18 different locations. Based on physiological tests and morphological characteristics of sexual structures, 72 isolates were identified as X. dendrorhous. Representative strains were studied by MSP-PCR fingerprinting and sequence analysis of the ITS region. MSP-PCR fingerprints were similar for the newly isolated strains, and were also identical to the profiles of the strains previously found in this region. Patagonian strains appear to be a genetically uniform and distinct population, supporting the hypothesis that the association with different host species has determined genetically distinct X. dendrorhous populations worldwide. X. dendrorhous was recovered from N. dombeyi and N. antarctica. Approximately half the sampling sites and samples were positive for X. dendrorhous, but the isolation recovery rate was low. X. dendrorhous was absent in the early stages of ascostromata maturation, becoming more abundant in later stages. The present work represents a step forward in the understanding of the natural distribution and ecology of this biotechnologically relevant yeast.Xanthophyllomyces dendrorhous (Phaffia rhodozyma asociado a estromas de Cyttaria hariotii en bosques de Nothofagus en el noroeste de la Patagonia. Se estudió la ocurrencia y la distribución de Xanthophyllomyces dendrorhous asociado a Cyttaria hariotii en tres especies de Nothofagus (N. dombeyi, N. antarctica y N. pumilio del noroeste de la Patagonia (Argentina, y los factores que podrían afectar esta distribución. El muestreo se realizó entre 2000 y 2007 en 18 sitios diferentes. Según las pruebas fisiológicas y las caracter

  19. Intraspecific trait variation and covariation in a widespread tree species (Nothofagus pumilio) in southern Chile.

    Science.gov (United States)

    Fajardo, Alex; Piper, Frida I

    2011-01-01

    • The focus of the trait-based approach to study community ecology has mostly been on trait comparisons at the interspecific level. Here we quantified intraspecific variation and covariation of leaf mass per area (LMA) and wood density (WD) in monospecific forests of the widespread tree species Nothofagus pumilio to determine its magnitude and whether it is related to environmental conditions and ontogeny. We also discuss probable mechanisms controlling the trait variation found. • We collected leaf and stem woody tissues from 30-50 trees of different ages (ontogeny) from each of four populations at differing elevations (i.e. temperatures) and placed at each of three locations differing in soil moisture. • The total variation in LMA (coefficient of variation (CV) = 21.14%) was twice that of WD (CV = 10.52%). The total variation in traits was never less than 23% when compared with interspecific studies. Differences in elevation (temperature) for the most part explained variation in LMA, while differences in soil moisture and ontogeny explained the variation in WD. Traits covaried similarly in the altitudinal gradient only. • Functional traits of N. pumilio exhibited nonnegligible variation; LMA varied for the most part with temperature, while WD mostly varied with moisture and ontogeny. We demonstrate that environmental variation can cause important trait variation without species turnover. © The Authors (2010). Journal compilation © New Phytologist Trust (2010).

  20. Individual-Tree Diameter Growth Models for Mixed Nothofagus Second Growth Forests in Southern Chile

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    Paulo C. Moreno

    2017-12-01

    Full Text Available Second growth forests of Nothofagus obliqua (roble, N. alpina (raulí, and N. dombeyi (coihue, known locally as RORACO, are among the most important native mixed forests in Chile. To improve the sustainable management of these forests, managers need adequate information and models regarding not only existing forest conditions, but their future states with varying alternative silvicultural activities. In this study, an individual-tree diameter growth model was developed for the full geographical distribution of the RORACO forest type. This was achieved by fitting a complete model by comparing two variable selection procedures: cross-validation (CV, and least absolute shrinkage and selection operator (LASSO regression. A small set of predictors successfully explained a large portion of the annual increment in diameter at breast height (DBH growth, particularly variables associated with competition at both the tree- and stand-level. Goodness-of-fit statistics for this final model showed an empirical coefficient of correlation (R2emp of 0.56, relative root mean square error of 44.49% and relative bias of −1.96% for annual DBH growth predictions, and R2emp of 0.98 and 0.97 for DBH projection at 6 and 12 years, respectively. This model constitutes a simple and useful tool to support management plans for these forest ecosystems.

  1. Agrobacterium rhizogenes vs auxinic induction for in vitro rhizogenesis of Prosopis chilensis and Nothofagus alpina.

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    Caro, Luis A; Santecchia, Natalia; Marinangeli, Pablo A; Curvetto, Néstor R; Hernández, Luis F

    2003-12-01

    The induction and improvement of in vitro rhizogenesis of microshoots of Prosopis chilensis (Mol.) Stuntz and Nothofagus alpina (Poep. et Endl. Oerst.) were compared using Agrobacterium rhizogenes (Ar) versus indole-3-butyric acid (IBA) in the culture media. Microshoots of P. chilensis (1-2 cm length), coming from in vitro grown seedlings, were cultivated in a modified Broadleaved Tree Medium (BTMm) containing half salt concentration of macronutrients and 0.05 mg x L(-1) benzilaminopurine (BAP). After 30 days, microshoots with 2-4 leaves were selected and cultured in BTMm-agar in presence or abscense of Ar and in combination with IBA. For N. alpina, the apical shoots with the first 2 true leaves, from 5 weeks old seedlings, were cultured in the abovementioned medium, but with 0.15 mg x L(-1) of BAP. After 2 months, microshoots with 2-3 leaves were selected and cultured in BTMm-agar, supplemented with 5 mg x L(-1) IBA or in liquid BTMm on perlite and, in the presence or absence of A. rhizogenes (Ar) and in combination with 3 mg x L(-1) IBA. Rooting in P. chilensis reached 100.0% when Ar infection was produced in the presence of IBA, increasing both, the number and dry weight of roots. In N. alpina, 90.0% of rooting efficiency was obtained when Ar infection was produced in liquid culture and in the absence of auxin.

  2. Surface-bound phosphatase activity in living hyphae of ectomycorrhizal fungi of Nothofagus obliqua.

    Science.gov (United States)

    Alvarez, Maricel; Godoy, Roberto; Heyser, Wolfgang; Härtel, Steffen

    2004-01-01

    We determined the location and the activity of surface-bound phosphomonoesterase (SBP) of five ectomycorrhizal (EM) fungi of Nothofagus oblique. EM fungal mycelium of Paxillus involutus, Austropaxillus boletinoides, Descolea antartica, Cenococcum geophilum and Pisolithus tinctorius was grown in media with varying concentrations of dissolved phosphorus. SBP activity was detected at different pH values (3-7) under each growth regimen. SBP activity was assessed using a colorimetric method based on the hydrolysis of p-nitrophenyl phosphate (pNPP) to p-nitrophenol phosphate (pNP) + P. A new technique involving confocal laser-scanning microscopy (LSM) was used to locate and quantify SBP activity on the hyphal surface. EM fungi showed two fundamentally different patterns of SBP activity in relation to varying environmental conditions (P-concentrations and pH). In the cases of D. antartica, A. boletinoides and C. geophilum, changes in SBP activity were induced primarily by changes in the number of SBP-active centers on the hyphae. In the cases of P. tinctorius and P. involutus, the number of SBP-active centers per μm hyphal length changed much less than the intensity of the SBP-active centers on the hyphae. Our findings not only contribute to the discussion about the role of SBP-active centers in EM fungi but also introduce LSM as a valuable method for studying EM fungi.

  3. Seasonal changes in the photosynthetic performance of two evergreen Nothofagus species in south central Chile Cambios estacionales en el desempeño fotosintético de dos especies siempreverdes de Nothofagus en el centro sur de Chile

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    RAFAEL ZÚÑIGA

    2006-12-01

    Full Text Available The evergreen Nothofagus dombeyi and Nothofagus nitida are important members of the temperate Chilean rainforest. They seldom grow together in nature. Nothofagus nitida is more susceptible to excess light and drought than N. dombeyi. We postulate that the different properties of the photosynthetic apparatus under common garden conditions of these species could explain their contrasting habitat preferences. The two species growing in a common garden in south central Chile were studied. The optimal photochemical efficiency (Fv/Fm of both species remained within normal values (»0.8 with the exception of a decrease in N. dombeyi at midday in summer, suggesting reversible reduction in photochemical efficiency of photosystem II (PSII. During summer the effective photochemical efficiency (F PSII, photochemical quenching (qP, photosynthesis (Amax, stomatal conductance (gs and transpiration rates (E in N. dombeyi were higher than in N. nitida. The highest increments in photoprotective pigments (zeaxanthin + antheraxanthin and lutein contents between predawn and midday were obtained in summer in N. dombeyi. In N. nitida a nocturnal retention of dissipative pigments, without a decrease in Fv/Fm, was found in winter. The results suggest that N. dombeyi showed a better photosynthetic performance than N. nitida under high light, high temperature, and drier conditions. These data support are consistent with the pioneer character of N. dombeyi and the semi-tolerant shade properties and more restricted distribution of N. nitida. These photosynthetic characteristics, along with their freezing and flooding resistance differences, may result from their habitat separationLas siempreverdes, Nothofagus dombeyi y Nothofagus nitida, representantes importantes de los bosques lluviosos templados de Chile, raramente crecen juntos en forma natural. Nothofagus nitida es más sensible al exceso de luz y déficit de agua que N. dombeyi. Se postula que diferentes propiedades

  4. Micropropagación in vitro de Nothofagus alpina utilizando fitohormonas

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    Luz García Cruzatty

    2015-09-01

    Full Text Available Nothofagus alpina es una de las especies forestales más importantes del Sur de Chile y Argentina, países donde se ha empezado con programas de mejoramiento genético. La micropropagación es una técnica muy útil en la clonación de árboles con fines de mejoramiento, por tanto, los objetivos planteados en esta investigación fueron: determinar la mejor concentración de fitohormonas 6-bencilaminopurina (BAP y ácido indol butírico (AIB y, el medio de cultivo idóneo para inducir el enraizamiento de brotes y la brotación de secciones nodales de N. alpina. Se evaluaron los medios de Murashige Skoog (MS y Wood Plant Medium (WPM, con la mitad de los macronutrientes (enraizamiento y los micronutrientes completos (multiplicación, suplementado con peptone (0.1%, sacarosa (2.0%, agar (0.7% y diferentes concentraciones de auxinas. El medio MS suplementado con 2 mg L-1 de AIB resultó mejor para inducir la producción de las raíces, tanto en número como en la longitud de la raíz principal. El mayor porcentaje de enraizamiento se registró en el medio WPM suplementado con 2 mg L-1 AIB. Los tratamientos para inducir multiplicación que incluyeron citoquinina originaron callos y no enraizaron; siendo mayor la presencia de callos en el medio WPM. Se sugiere que la aplicación de citoquininas no es indispensable para la brotación, puesto que en los tratamientos testigos hubo una buena brotación; lo que hace suponer que el material vegetal utilizado tiene suficiente niveles endógenos de esta fitohormona.

  5. Site quality influence over understory plant diversity in old-growth and harvested Nothofagus pumilio forests

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    E. A. Gallo

    2013-04-01

    Full Text Available Aim of study: The effects and interactions of shelterwood forest harvesting and site qualities over understory plant species diversity and composition were compared among primary and harvested Nothofagus pumilio forests.Area of study: Tierra del Fuego (Argentina, on three pure conditions (one and six year-old harvested, and primary without previous harvesting forests and three site qualities (high, medium and low.Material and Methods: Understory richness and cover (% were registered in five replicates of 1 hectare each per treatment. Taxonomic species were classified in categories (groups, origin and life forms. Two-way ANOVAs and multivariate analyses were conducted.Main results: Shelterwood harvesting and site quality significantly influenced understory cover and richness, which allow the introduction of native and exotic species and increasing of dicot and monocot covers. In dicots, monocots, exotics and total groups, higher richness and covers were related to time. Meanwhile, cover reached similar high values in all site qualities on dicot, native and total groups. On the other hand, monocot and exotic richness and cover remain similar in primary and recently harvested forests, and greatly increased in old harvested forests. Mosses and ferns were among the most sensitive groups.Research highlights: Impacts of shelterwood cut depend on site quality of the stands and time since harvesting occurs. For this, different site quality stands should received differential attention in the development of conservation strategies, as well as variations in the shelterwood implementation (as irregularity and patchiness should be considered to better promote understory plant species conservation inside managed areas.Key words: plant species conservation; years after harvesting; forest management; Tierra del Fuego.

  6. Regeneración de un bosque mixto de Nothofagus (Nothofagaceae después de una corta selectiva Regeneration of a Nothofagus (Nothofagaceae mixed forest after selective cutting

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    ALEJANDRO DEZZOTTI

    2003-12-01

    Full Text Available El estudio de la ecología de la regeneración natural del bosque constituye una parte esencial de la silvicultura. El cerro Tren Tren (40°12' S, 71°26' O, 1.367 m, Reserva Mapuche Curruhuinca, Argentina está ocupado por un bosque cerrado compuesto por Nothofagus dombeyi, N. nervosa y N. obliqua. En 1994 se estimó la densidad de renovales (diámetro en la base del tallo Understanding forest regeneration is essential to develop sound, ecologically-based silvicultural practices. Mount Tren Tren (40°12' S, 71°26' W, 1,367 m, Reservation Mapuche Curruhuinca, Argentina is occupied by a closed stand of Nothofagus dombeyi, N. obliqua, and N. nervosa. In 1994, tree regeneration (root collar diameter < 10 cm was estimated to be 90 ind ha-1. After that, a group selection silvicultural system was implemented and the resulting 10 artificial gaps of between 1,587 and 4,322 m² were enclosed to prevent grazing by domestic livestock. Size and age structure of regeneration were analysed based on systematic and random samplings. All tree species became established simultaneously within the artificial gaps. However, the less light demanding N. nervosa exhibited a mean age slightly larger given its differential persistence as "advanced regeneration" previous to cutting treatment. Tree regeneration was estimated in 97,006 ind ha-1 (68 % of N. dombeyi, 20 % of N. obliqua, and 12 % of N. nervosa. Regeneration abundance and composition were unrelated to shape and size of regeneration gaps, nor to abundance of adult trees within the stand and along the gap boundaries. A significant positive effect of the enclosure on plant was observed. The 86 % of juvenile Nothofagus were present when understory height and cover were low to intermediate. The management plan is considered adequate if the abundance of regeneration is compared before and after its implementation, and encourages the use and conservation of this forest type under the current silvicultural system

  7. Caída de tefra y su influencia sobre la estructura y dinámica de los bosques andinos de Nothofagus en el Parque Nacional Puyehue, Chile

    Science.gov (United States)

    Mauricio Montiel; Mauro E González; Charles M Crisafulli

    2016-01-01

    Tephra fall influences the structure and dynamics of Andean Nothofagus (beech) forests in Puyehue National Park, Chile. Forest mortality and subsequent establishment, structure and composition have been affected by the eruption of the Puyehue-Cordon Caulle volcano complex.

  8. Evaluation of the physical, mechanical and biological properties of the combined wood-plastic in Nothofagus Pumilio wood

    International Nuclear Information System (INIS)

    Benedetto Acuna, Andres

    2010-01-01

    In this project he studied the physical, mechanical and biological properties of wood-plastic combinations (WPC) in timber Nothofagus pumilio (Lenga) impregnated with the monomer methyl methacrylate (MMA), trying to get a hold and maximum penetration into the wood . It was used for impregnation method fills the cell (Bethell). To achieve the polymerization, the MMA once absorbed by the specimens under study are irradiated with gamma rays at a dose of 25 kGy, ensuring a high percentage of final polymerization, which fluctuated between 55.09% and 84.48%. The tests applied to the specimens were moisture content, dimensional stability, density, compression perpendicular to grain, compression parallel to grain to grain compression 'new' Janka hardness, shear parallel to grain, static bending and termites. In general, except for the static bending test, the WPC had an increase in their property, being the tests of hardness, density and water absorption which achieved higher profits, increasing their properties at 104%, 79% and 75% respectively compared to untreated specimens. From the economic viewpoint, the production of an inch Lenga timber has a cost of $ 19,805, so it may be feasible marketing both domestically and internationally (author)

  9. Yeast and yeast-like fungi associated with dry indehiscent fruits of Nothofagus nervosa in Patagonia, Argentina.

    Science.gov (United States)

    Fernández, Natalia V; Mestre, M Cecilia; Marchelli, Paula; Fontenla, Sonia B

    2012-04-01

    Nothofagus nervosa (Raulí) is a native tree species that yields valuable timber. It was overexploited in the past and is currently included in domestication and conservation programs. Several research programs have focused on the characterization of epiphytic microorganisms because it has been demonstrated that they can affect plant-pathogen interactions and/or promote plant growth. Although the microbial ecology of leaves has been well studied, less is known about microorganisms occurring on seeds and noncommercial fruits. In this work, we analyzed the yeast and yeast-like fungi present on N. nervosa fruits destined for the propagation of this species, as well as the effects of fruit preservation and seed dormancy-breaking processes on fungal diversity. Morphological and molecular methods were used, and differences between fungal communities were analyzed using a similarity index. A total of 171 isolates corresponding to 17 species were recovered, most of which belong to the phylum Ascomycota. The majority of the species develop mycelia, produce pigments and mycosporines, and these adaptation strategies are discussed. It was observed that the preservation process considerably reduced yeast and yeast-like fungal diversity. This is the first study concerning microbial communities associated with this ecologically and economically important species, and the information presented is relevant to domestication programs. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  10. Are trait-scaling relationships invariant across contrasting elevations in the widely distributed treeline species Nothofagus pumilio?

    Science.gov (United States)

    Fajardo, Alex

    2016-05-01

    The study of scaling examines the relative dimensions of diverse organismal traits. Understanding whether global scaling patterns are paralleled within species is key to identify causal factors of universal scaling. I examined whether the foliage-stem (Corner's rules), the leaf size-number, and the leaf mass-leaf area scaling relationships remained invariant and isometric with elevation in a wide-distributed treeline species in the southern Chilean Andes. Mean leaf area, leaf mass, leafing intensity, and twig cross-sectional area were determined for 1-2 twigs of 8-15 Nothofagus pumilio individuals across four elevations (including treeline elevation) and four locations (from central Chile at 36°S to Tierra del Fuego at 54°S). Mixed effects models were fitted to test whether the interaction term between traits and elevation was nonsignificant (invariant). The leaf-twig cross-sectional area and the leaf mass-leaf area scaling relationships were isometric (slope = 1) and remained invariant with elevation, whereas the leaf size-number (i.e., leafing intensity) scaling was allometric (slope ≠ -1) and showed no variation with elevation. Leaf area and leaf number were consistently negatively correlated across elevation. The scaling relationships examined in the current study parallel those seen across species. It is plausible that the explanation of intraspecific scaling relationships, as trait combinations favored by natural selection, is the same as those invoked to explain across species patterns. Thus, it is very likely that the global interspecific Corner's rules and other leaf-leaf scaling relationships emerge as the aggregate of largely parallel intraspecific patterns. © 2016 Botanical Society of America.

  11. Plant effects on soil carbon storage and turnover in montane beech (Nothofagus) forest and adjacent tussock grassland in New Zealand

    International Nuclear Information System (INIS)

    Tate, K.R.; Scott, N.A.; Ross, D.J.; Parshotam, A.; Claydon, J.J.

    2000-01-01

    Land cover is a critical factor that influences, and is influenced by, atmospheric chemistry and potential climate changes. As considerable uncertainty exists about the effects of differences in land cover on below-ground carbon (C) storage, we have compared soil C contents and turnover at adjacent, unmanaged, indigenous forest (Nothofagus solandri var. cliffortiodes) and grassland (Chionochloa pallens) sites near the timberline in the same climo-edaphic environment in Craigieburn Forest Park, Canterbury, New Zealand. Total soil profile C was 13% higher in the grassland than in the forest ( 19.9 v. 16.7 kg/m 2 ), and based on bomb 14 C measurements, the differences mainly resulted from more recalcitrant soil C in the grassland (5.3 v. 3.0 kg/m 2 ). Estimated annual net primary production was about 0.4 kg C/m 2 for the forest and 0.5 kg C/m 2 for the grassland; estimated annual root production was about 0.2 and 0.4 kg C/m 2 , respectively. In situ soil surface CO 2 -C production was similar in the grassland and the forest. The accumulation of recalcitrant soil C was unrelated to differences in mineral weathering or soil texture, but was apparently enhanced by greater soil water retention in the grassland ecosystem. Thus, contrary to model (ROTHC) predictions, this soil C fraction could be expected to respond to the effects of climate change on precipitation patterns. Overall, our results suggest that the different patterns of soil C accumulation in these ecosystems have resulted from differences in plant C inputs, soil aluminium, and soil physical characteristics, rather than from differences in soil mineral weathering or texture. Copyright (2000) CSIRO Australia

  12. Sapling growth and crown expansion in canopy gaps of Nothofagus pumilio (lenga) forests in Chubut, Patagonia, Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Bernal, P. M.; Defosse, G. E.; Quinteros, C. P.; Bava, J. O.

    2012-07-01

    In the province of Chubut in Patagonia, Argentina, Nothofagus pumilio forests (locally known as lenga), are managed through selective cuts, which imply the opening of canopy gaps. This management scheme is carried out without taking into consideration the changes of sapling requirements through either a cutting cycle or the precipitation gradient in which these forests thrive. To analyze these changes, we inferred the facilitation-competition balance between the canopy and regeneration, studying the effects of precipitation levels, gap size and gap age on saplings growth in height on 45 canopy gaps artificially created between 1960 and 1993. Results showed that during the first 20 years since gap opening, growth of regeneration is determined by light availability in mesic sites and by water availability in xeric sites. However, differences due to precipitation levels gradually decrease over time. Moreover, in the period between 20 and 35 years after gap opening, in both mesic and xeric sites, growth is limited by light availability. This indicates that in xeric sites, sapling growth requirements shift from a water-dependent situation to a light-dependent situation. The average closing rate of gaps due to lateral growth of bordering trees is high enough so that within the proposed gap size range, gap healing can occur before regeneration reaches the upper stratum. Consequently, in mesic sites gap opening can be done by a single operation that generates gaps with diameters of approximately twice the average height of the canopy (D/H). While in xeric environments, lenga seedling establishment and initial growth require the cover of small gaps, but advanced regeneration requires bigger gaps to reach the canopy. For this reason, gaps should be opened in two stages: the first gaps should be opened with a D/H between 0.8 and 1, and after a cutting cycle of 35 years, these openings should be enlarged to a D/H between 1.5 and 2. The close relationship maintained between the

  13. Responses of two températe evergreen Nothofagus species to sudden and gradual waterlogging: relationships with distribution patterns Respuestas de dos especies siempreverdes de Nothofagus al anegamiento gradual y repentino: relaciones con patrones de distribución

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    FRIDA PIPER

    2008-06-01

    Full Text Available The effects of gradual waterlogging on trees have been little studied. The températe evergreens Nothofagus nítida and N. dombeyi are differentially distributed on soil moisture gradients, only the former being common on poorly-drained sites. We compared the relative height growth rate (RGR H and foliage loss of seedlings subjected experimentally to normal drainage (soil at field capacity, sudden waterlogging and gradual waterlogging for two months to determine which waterlogging regime more accurately predicts interspecific differences in tolerance, as evident from natural distributions. RGR H was similar between species but differed between treatments (normal watering > gradual waterlogging = sudden waterlogging. Sudden waterlogging caused massive foliage loss in the two species, but gradual waterlogging caused much greater foliage loss in N. dombeyi than in N. nítida, indicating some degree of acclimation by the latter species. Linear regressions indicated that RGR H was negatively affected by foliage loss in both species, without differences between them. Since no difference in RGR H was found between species in the waterlogging treatments, but yet in foliage loss, other mechanisms may be in volved in the short term growth reduction of N. nítida. Effects of waterlogging on long-term performance in the field were evaluated by reciprocal transplants between a poorly-drained site naturally occupied by N. nítida, and a well drained site naturally occupied by N. dombeyi. After two growing seasons, N. dombeyi had significantly lower specific leaf área (SLA and RGR H, at the poorly drained site than at its original site. At the poorly drained site N. nítida achieved 100 % survival, compared with 73.5 % in N. dombeyi. Reduced growth and survival of N. dombeyi associated with the negative effects on carbón gain of extensive foliage loss and reduced SLA may thus exelude it from the wetter sites. We conclude that tolerance may be better

  14. Effect of wildfire on soil physical and chemical properties in a Nothofagus glauca forest, Chile Efecto del fuego en las propiedades físicas y químicas en un bosque de Nothofagus glauca en Chile

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    CREIGHTON M. LITTON

    2003-12-01

    Full Text Available Effects of a wildfire on soil chemical and physical properties in a Nothofagus glauca (Phil. Krasser forest in the Coastal Mountain Range of south-central Chile were investigated. Response of the soil during the first two years following a wildfire was examined, where data from soil in a burned forest were compared to that in an adjacent, unburned stand. The effects that wildfire have on soil properties in this highly fragmented ecosystem are not well understood, but results from this study suggest similar responses to those found in other mediterranean forest systems. Both physical (bulk density, percent soil moisture, and soil organic matter content and chemical properties (exchangeable inorganic nitrogen, extractable phosphorus, exchangeable potassium, and soil pH were examined, and data presented here suggest that soil properties vary in their initial response to fire in this ecosystem. Soil organic matter content and soil moisture decreased following fire and remained lower than values from unburned plots for the duration of the study. Exchangeable potassium increased initially after burning, but values in burned plots decreased with time and by the end of two years were significantly lower than in unburned soil. In turn, extractable phosphorus and soil pH both increased immediately following wildfire and values in burned plots remained significantly higher than unburned plots for the entire measurement period. Exchangeable inorganic nitrogen reached higher levels in soil of burned plots for the autumn measurements (April 1997 and 1998 and lower values in burned plots for the spring measurements (November 1997 and 1998. Soil bulk density remained unchanged following fire. In general, changes in soil properties following fire were greatest at the 0-5 cm layer and more modest at the 5-10 cm sampling depth. These changes were related primarily to oxidation of the detrital layer during fire and concurrent changes in the soil environment

  15. Variación estacional y potencial enzimático de microhongos asociados con la descomposición de hojarasca de Nothofagus pumilio Seasonal variation and enzymatic potential of microfungi associated with the decomposition of Nothofagus pumilio leaf litter

    OpenAIRE

    EDUARDO VALENZUELA; SERGIO LEIVA; ROBERTO GODOY

    2001-01-01

    Se estudió la variación estacional y el potencial enzimático de microhongos aislados desde el follaje y hojarasca de Nothofagus pumilio sometida a degradación natural durante 1 año. La investigación se realizó en un bosque de N. pumilio ubicado en una microcuenca del Valle de Antillanca, Parque Nacional Puyehue (40° 47' S, 72° 12' O, 1.120 m de altitud). Hojas senescentes colectadas desde árboles de N. pumilio se depositaron en bolsas de malla de nylon ("litter bags") y se sometieron a degrad...

  16. Encapsulado de Embriones Somáticos y Embriones Cigóticos para Obtención de Semillas Artificiales de Raulí (Nothofagus alpina (Poepp. & Endl.) Oerst.)

    OpenAIRE

    Cartes R, Priscila; Castellanos B, Hermes; Ríos L, Darcy; Sáez C, Katia; Spierccolli H, Scarlette; Sánchez O, Manuel

    2009-01-01

    Somatic and zygotic embryos from mature seeds of rauli-beech, Nothofagus alpina (Poepp. & Endl.) Oerst., were encapsulated in different artificial endosperms in order to generate a cover that fulfills the function of nourishment and protection of the embryos, facilitating their later germination. The content of sodium alginate varied by 4%, 3%, and 2%, as did the immersion time in calcium chloride (CaCl2), which acts as complexing agent. The artificial endosperm components of the Murashige an...

  17. Species effect on the water use efficiency of a mixed forest of beech (Fagus sylvatica L.), Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) and silver fir (Abies alba Mill.) in Belgium Ardennes.

    Science.gov (United States)

    Soubie, Rémy; Heinesch, Bernard; Aubinet, Marc; Vincke, Caroline

    2010-05-01

    Induced by climate change, intensity and frequency of droughts should be more important for the next century. How does water availability affect the physiology of woody plants at the species and stand scale? Carbon and water vapour fluxes measurements of a mixed forest (deciduous and coniferous) were performed for over ten years by the eddy covariance method in Belgian Ardennes (Aubinet et al, 2001) as a part of the CarboEurope project. Whereas carbon fluxes have been analyzed in detailed and good estimations of the Net Ecosystem Exchange (NEE) and Gross Primary Production (GPP) were obtained, a thorough analysis of water vapour fluxes remains to be done. Improving analysis of water vapour fluxes and monitoring species transpiration will contribute to the estimation of the water use efficiency, WUE, at both the species and stand scale. The WUE well characterizes the vegetation productivity and ecosystem response to environmental factors. It also allows evaluating the sensitivity of temperate woody species to drought. The species concerned are beech (Fagus sylvatica L.), Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) and silver fir (Abies alba Mill.). Since summer 2009 we monitor and analyze each species water use by measuring sap flow with the thermal dissipation method (Granier, 1987). Results at the species level will then be upscaled and compared to stand water vapour fluxes measurements obtained by the eddy covariance methodology. Transpiration of each species will be analyzed in relation with their own phenological and ecophysiological attributes, ecosystem soil and atmospheric conditions, to clarify among others their behaviour in case of water deficit. Data are actually analysed, the presented results will concern the 2009, and a part of 2010 growing season.

  18. Imprints of climate signals in a 204 year 18O tree-ring record of Nothofagus pumilio from Perito Moreno Glacier, southern Patagonia (50°S).

    Science.gov (United States)

    Grießinger, Jussi; Langhamer, Lukas; Schneider, Christoph; Saß, Björn-Lukas; Steger, David; Skvarca, Pedro; Braun, Matthias H.; Meier, Wolfgang J.-H.; Srur, Ana M.; Hochreuther, Philipp

    2018-04-01

    A 204 year-long record of 18O in tree-ring cellulose of southern beech (Nothofagus pumilio) from a site near Perito Moreno Glacier (50°S) in southern Patagonia was established to assess its potential for a climate reconstruction. The annually resolved oxygen isotope chronology is built out of seven individual tree-ring 18O series with a significant mean inter-series correlation (r = 0.61) and is the first of its kind located in Southern America south of 50°S. Over a common period from 1960 to 2013 of available stationary and high-resolution gridded CRU TS v. 4.01 data, the 18O chronology exhibits a strong sensitivity towards hydroclimatic as well as temperature parameters as revealed by correlation analyses. Among these, positive correlations with maximum temperature in the first part of the summer season (CRU rONDJ = 0.51, pAmerica. The modulation of positive and negative anomalies within this series can be interlinked to changes in moisture source origin as revealed by backward trajectory modeling. Additionally, these anomalies can be directly associated to positive or negative phases of the Antarctic Oscillation Index (AAOI) and therefore the strength of the Westerlies. Aligned by the analysis on the influence of different main weather types on the 18O chronology it is shown that such time-series hold the potential to additionally capture their respective influence and change during the last centuries.

  19. Living on the edge: adaptive and plastic responses of the tree Nothofagus pumilio to a long-term transplant experiment predict rear-edge upward expansion.

    Science.gov (United States)

    Mathiasen, Paula; Premoli, Andrea C

    2016-06-01

    Current climate change affects the competitive ability and reproductive success of many species, leading to local extinctions, adjustment to novel local conditions by phenotypic plasticity or rapid adaptation, or tracking their optima through range shifts. However, many species have limited ability to expand to suitable areas. Altitudinal gradients, with abrupt changes in abiotic conditions over short distances, represent "natural experiments" for the evaluation of ecological and evolutionary responses under scenarios of climate change. Nothofagus pumilio is the tree species which dominates as pure stands the montane forests of Patagonia. We evaluated the adaptive value of variation in quantitative traits of N. pumilio under contrasting conditions of the altitudinal gradient with a long-term reciprocal transplant experimental design. While high-elevation plants show little response in plant, leaf, and phenological traits to the experimental trials, low-elevation ones show greater plasticity in their responses to changing environments, particularly at high elevation. Our results suggest a relatively reduced potential for evolutionary adaptation of high-elevation genotypes, and a greater evolutionary potential of low-elevation ones. Under global warming scenarios of forest upslope migration, high-elevation variants may be outperformed by low-elevation ones during this process, leading to the local extinction and/or replacement of these genotypes. These results challenge previous models and predictions expected under global warming for altitudinal gradients, on which the leading edge is considered to be the upper treeline forests.

  20. Establishment of ectomycorrhizal fungal community on isolated Nothofagus cunninghamii seedlings regenerating on dead wood in Australian wet temperate forests: does fruit-body type matter?

    Science.gov (United States)

    Tedersoo, Leho; Gates, Genevieve; Dunk, Chris W; Lebel, Teresa; May, Tom W; Kõljalg, Urmas; Jairus, Teele

    2009-08-01

    Decaying wood provides an important habitat for animals and forms a seed bed for many shade-intolerant, small-seeded plants, particularly Nothofagus. Using morphotyping and rDNA sequence analysis, we compared the ectomycorrhizal fungal community of isolated N. cunninghamii seedlings regenerating in decayed wood against that of mature tree roots in the forest floor soil. The /cortinarius, /russula-lactarius, and /laccaria were the most species-rich and abundant lineages in forest floor soil in Australian sites at Yarra, Victoria and Warra, Tasmania. On root tips of seedlings in dead wood, a subset of the forest floor taxa were prevalent among them species of /laccaria, /tomentella-thelephora, and /descolea, but other forest floor dominants were rare. Statistical analyses suggested that the fungal community differs between forest floor soil and dead wood at the level of both species and phylogenetic lineage. The fungal species colonizing isolated seedlings on decayed wood in austral forests were taxonomically dissimilar to the species dominating in similar habitats in Europe. We conclude that formation of a resupinate fruit body type on the underside of decayed wood is not necessarily related to preferential root colonization in decayed wood. Rather, biogeographic factors as well as differential dispersal and competitive abilities of fungal taxa are likely to play a key role in structuring the ectomycorrhizal fungal community on isolated seedlings in decaying wood.

  1. Encapsulated Somatic Embryos and Zygotic Embryos for Obtaining Artificial Seeds of Rauli-Beech (Nothofagus alpina (Poepp. & Endl. Oerst. Encapsulado de Embriones Somáticos y Embriones Cigóticos para Obtención de Semillas Artificiales de Raulí (Nothofagus alpina (Poepp. & Endl. Oerst.

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    Priscila Cartes R

    2009-03-01

    Full Text Available Somatic and zygotic embryos from mature seeds of rauli-beech, Nothofagus alpina (Poepp. & Endl. Oerst., were encapsulated in different artificial endosperms in order to generate a cover that fulfills the function of nourishment and protection of the embryos, facilitating their later germination. The content of sodium alginate varied by 4%, 3%, and 2%, as did the immersion time in calcium chloride (CaCl2, which acts as complexing agent. The artificial endosperm components of the Murashige and Skoog medium (MS were added, supplemented with 0.5 mg L-1 indolacetic acid (IAA, 0.5 mg L-1 naphthaleneacetic acid (NAA, 2 mg L-1 6-benzylaminopurine (BAP and 30 g L-1 sucrose. The germinative behaviors of encapsulated somatic and zygotic embryos were evaluated after 4 wk. Comparing the percentages of germination reached by encapsulated somatic and zygotic embryos it was observed that they had similar germinative behavior according to the type of encapsulation applied. However, zygotic embryos substantially exceeded the germination levels reached by somatic embryos, 100% vs. 45% respectively.Embriones somáticos y cigóticos provenientes de semillas maduras de raulí, Nothofagus alpina (Poepp. & Endl. Oerst., se encapsularon en diferentes endospermas sintéticos con el fin de generar una cubierta que cumpla la función de nutrir y proteger al embrión para facilitar su posterior germinación. Se varió el contenido de alginato de sodio al 4%, 3% y 2% y el tiempo de inmersión en cloruro de calcio (CaCl2, el que actúa como agente acomplejante. Además, a la matriz artificial se adicionaron componentes del medio Murashige y Skoog (MS suplementado con: 0,5 mg L-1 de indolacetic acid (IAA, 0,5 mg L-1 de ácido naftalenacético (NAA, 2 mg L-1 de 6-bencilaminopurina (BAP y 30 gL-1 de sacarosa. Al cabo de 4 semanas el porcentaje de germinación de los embriones somáticos y cigóticos encapsulados tuvieron similar comportamiento germinativo según el tipo de

  2. Morfología y Anatomía del Ápice Caulinar de Nothofagus dombeyi (Nothofagaceae a lo largo de un año Morfology and anatomy of the shoot apex of Nothofagus dombeyi (Nothofagaceae along a year

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    Soledad García

    2006-07-01

    Full Text Available En el presente estudio se evaluó la posible variación anual de la morfología y la anatomía del ápice caulinar de coihue, Nothofagus dombeyi (Nothofagaceae. A partir de muestras tomadas a lo largo de un año calendario, se realizaron cortes longitudinales de las yemas terminales con micrótomo de congelación. Independientemente de la época del año, una yema terminal está conformada por un meristema apical y rudimentos de tallo y hojas. Los primordios foliares proximales tienen mayor tamaño y grado de diferenciación que los distales. En la axila de cada estípula se destaca la presencia de coléteres. Cada coléter se comunica vascularmente con la estípula correspondiente. El número de primordios foliares por yema es constante entre abril y octubre y disminuye posteriormente al incrementarse el número de hojas expandidas, aunque sin llegar a cero. Al final de la estación de crecimiento se distinguen yemas de mayor y yemas de menor tamaño; estas últimas se secan y desprenden del tallo antes de la primavera siguiente. Dentro de una yema se evidencian, en un momento dado, distintos grados de diferenciación entre primordios foliares proximales y distales y entre la lámina y las estípulas de los primordios más proximales.The present study evaluates the possible annual variation in the morphology and anatomy of the shoot apex of Nothofagus dombeyi (Nothofagaceae. From samples taken over one year, longitudinal slices of terminal buds were cut with a freezing microtome. Irrespective of the time of the year, a terminal bud consists of an apical meristem and rudiments of stem and leaves. Proximal primordia are larger and have a higher degree of differentiation than distal primordia. Around the axil of each stipule colleters are present. Each colleter is connected with the corresponding stipule through a conducting strand. The number of leaf primordia per bud is constant between April and October and diminishes later on as leaf expansion

  3. Patrones de dispersión de semillas y colonización de Misodendrum punctulatum (Misodendraceae en un matorral postfuego de Nothofagus antarctica (Nothofagaceae del noroeste de la Patagonia Misodendrum punctulatum (Misodendraceae seed dispersal and colonization patterns on a Nothofagus antarctica (Nothofagaceae post-fire shrubland from Northwestern Patagonia

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    NORLAN TERCERO-BUCARDO

    2010-01-01

    Full Text Available El patrón espacial de la dispersión puede afectar el patrón espacial de establecimiento condicionando la estructura de la vegetación. Este trabajo analiza la magnitud de la dispersión y la colonización (infección de la planta hemiparásita Misodendrum punctulatum (Misodendraceae. Este estudio fue realizado en un matorral postfuego de Nothofagus antárctica (hospedador. Nuestra hipótesis plantea que el patrón de dispersión anemófila de las semillas de M. punctulatum condiciona el patrón de infección (colonización sobre N. antárctica y que ambos procesos (dispersión y colonización son asimétrico en la misma dirección en función del viento predominante. Se evaluó la dispersión a campo contando el número de semillas sobre troncos y ramas desde arbustos remanentes infectados (hospedadores focales hacia cada punto cardinal. La colonización se evaluó registrando el número de infecciones sobre cada hospedador a lo largo de franjas trazadas hacia cada orientación desde los arbustos focales. Se observó que la cantidad de semillas dispersadas declina con la distancia desde la fuente de semillas, ajustándose a una distribución exponencial negativa. La mayor distancia de dispersión primaria fue de 10 m hacia el este. Respecto a la colonización la mayor distancia de nuevos establecimientos fue 22.5 m en dirección sur. Por otro lado, el número de infecciones desde los arbustos focales fue menor al oeste (1 infectado: 10 no infectados que en las otras direcciones (1 infectado: 6 no infectados. Ambos procesos presentaron un patrón de distribución similar y asimétrica como consecuencia de la dirección de los vientos predominantes y se observó una alta correlación espacial entre la dispersión de semillas y el establecimiento de las infecciones. Estos resultados de dispersión y colonización permiten comprender los patrones de distribución espacial de esta planta hemiparásita y entender su dinámica de infección. Los

  4. Imprints of Climate Signals in a 204 Year δ18O Tree-Ring Record of Nothofagus pumilio From Perito Moreno Glacier, Southern Patagonia (50°S

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    Jussi Grießinger

    2018-04-01

    Full Text Available A 204 year-long record of δ18O in tree-ring cellulose of southern beech (Nothofagus pumilio from a site near Perito Moreno Glacier (50°S in Southern Patagonia was established to assess its potential for a climate reconstruction. The annually resolved oxygen isotope chronology is built out of seven individual tree-ring δ18O series with a significant mean inter-series correlation (r = 0.61 and is the first of its kind located in Southern America south of 50°S. Over a common period from 1960 to 2013 of available stationary and high-resolution gridded CRU TS v. 4.01 data, the δ18O chronology exhibits a strong sensitivity toward hydroclimatic as well as temperature parameters as revealed by correlation analyses. Among these, positive correlations with maximum temperature in the first part of the summer season (CRU rONDJ = 0.51, p < 0.01 and negative correlations with precipitation in the latter half of the vegetation period (CRU rONDJ = −0.54, p < 0.01 show the highest sensitivities. A strong supra-regional influence of the Southern Annular Mode (SAM is clearly recorded in this chronology as indicated by significant positive correlations during the vegetation period (rONDJ = 0.62, p < 0.01. This indicates that the presented δ18O-chronology shows great promise to reconstruct the influence and variability of the SAM within the last two centuries in southern South America. The modulation of positive and negative anomalies within this series can be interlinked to changes in moisture source origin as revealed by backward trajectory modeling. Additionally, these anomalies can be directly associated to positive or negative phases of the Antarctic Oscillation Index (AAOI and therefore the strength of the Westerlies. Aligned by the analysis on the influence of different main weather types on the δ18O chronology it is shown that such time-series hold the potential to additionally capture their respective influence and change during the last centuries.

  5. Endogenous Quantification of Abscisic Acid and Indole-3-Acetic Acid in Somatic and Zigotic Embryos of Nothofagus alpina (Poepp. & Endl. Oerst Cuantificación Endógena de Ácido Abscísico y Ácido Indol-3 Acético en Embriones Somáticos y Cigóticos de Nothofagus alpina (Poepp. & Endl. Oerst

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    Pricila Cartes Riquelme

    2011-12-01

    Full Text Available Abscisic acid (ABA and indole-3-acetic acid (IAA participate in the propagation of plants by somatic embryogenesis, causing polar structural differentiation of the embryo. The goal of the assay was to compare endogenous levels of ABA and IAA between somatic embryos (SE and zygotic embryos (ZE of Nothofagus alpina (Poepp. & Endl. Oerst. In this study, a somatic embryo maturation assay involving the addition of varying concentrations of exogenous ABA was performed on cotyledonary-stage of N. alpina. Furthermore, the endogenous levels of ABA and IAA were quantified in the immature ZE, the mature ZE, and the embryonic axis of a mature embryo of N. alpina. The current study utilized high performance liquid chromatography (HPLC for quantification. The maturation treatments performed did not present significant differences in the endogenous ABA levels in SE. However, significant differences did exist in levels of ABA and IAA between SE submitted to the different maturation treatments and mature ZE of N. alpina. The application of exogenous ABA to the culture medium increased endogenous ABA levels, therefore, increasing the number of germinated somatic embryos. Thus, the plant conversion process was also successfully completed in somatic embryos of N. alpina.El ácido abscísico (ABA y el ácido indol 3 acético (IAA participan en el proceso de propagación de plantas mediante embriogénesis somática, ya que permiten la diferenciación de la estructura polar del embrión, órganos y regiones meristemáticas de éste. En este estudio se llevó a cabo un ensayo de maduración de embriones somáticos en estado cotiledonar con la adición de diferentes concentraciones de ABA exógeno, además se determinaron niveles endógenos entre ZE inmaduro, ZE maduro, y eje embrionario aislado desde el embrión maduro para luego comparar niveles endógenos de ABA e IAA en embriones somáticos (SE y cigóticos (ZE de raulí, Nothofagus alpina (Poepp. & Endl. Oerst. La

  6. Teledetección satelital cuantitativa para estimar el área basal del bosque de Nothofagus pumilio (Nothofagaceae: El rol del índice de área foliar como información auxiliar Quantitative remote sensing to estimate basal area in Nothofagus pumilio (Nothofagaceae forest: The role of leaf area index as ancillary information

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    GASTÓN M DÍAZ

    2011-12-01

    Full Text Available Los bosques de lenga (Nothofagus pumilio son el recurso forestal más importante de la región andino patagónica argentina, sin embargo, para implementar planes de manejo en pos de prevenir o revertir su degradación es necesario disponer de mayor información sobre su estructura. Una alternativa para obtener esa información es relacionar datos satelitales con las características del bosque a través de modelos físicos y estadísticos. Pero, ¿cuál es el método más eficaz? El índice de área foliar (IAF se encuentra relacionado con la reflectividad del dosel vegetal a través del modelo de transferencia radiativa PROSAIL, lo que permite desarrollar técnicas de teledetección satelital para estimar el IAF con bases físicas, en vez de con modelos estadísticos. De ese modo se puede aprovechar la relación empírico-biológica existente entre el IAF y la estructura del bosque para estimar el área basal. El objetivo principal fue comparar la exactitud de tres métodos para estimar el área basal de la lenga con datos SPOT-5. Los métodos comparados fueron: estadístico directo (ED, estadístico de dos pasos (E2P y físico-estadístico de dos pasos (FE2P. La exactitud fue evaluada con 24 parcelas no involucradas en el ajuste o calibración de los modelos. No se hallaron diferencias significativas en la exactitud de la alternativa físico-estadística en comparación con las netamente estadísticas. Sin embargo, en base al análisis conjunto de los resultados y lo reportado por otros investigadores, se concluye que la ventaja de utilizar modelos físicos radica en la mayor robustez de la estimación y no en la mayor exactitud.Lenga forests (Nothofagus pumilio are the most important forest resource of the Argentinean Andean Patagonia, however, more information about their structure is needed to implement forest management policies and practices in order to prevent their degradation and revert it. One option to obtain this kind of information

  7. Variación estacional y potencial enzimático de microhongos asociados con la descomposición de hojarasca de Nothofagus pumilio Seasonal variation and enzymatic potential of microfungi associated with the decomposition of Nothofagus pumilio leaf litter

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    EDUARDO VALENZUELA

    2001-12-01

    Full Text Available Se estudió la variación estacional y el potencial enzimático de microhongos aislados desde el follaje y hojarasca de Nothofagus pumilio sometida a degradación natural durante 1 año. La investigación se realizó en un bosque de N. pumilio ubicado en una microcuenca del Valle de Antillanca, Parque Nacional Puyehue (40° 47' S, 72° 12' O, 1.120 m de altitud. Hojas senescentes colectadas desde árboles de N. pumilio se depositaron en bolsas de malla de nylon ("litter bags" y se sometieron a degradación natural en el piso del bosque durante 1 año (marzo 1997-marzo 1998, realizando muestreos trimestrales. Para el aislamiento de microhongos desde las hojas se utilizó el método de las diluciones, con agar extracto de malta al 2 % como medio de cultivo. Para determinar los potenciales degradativos de los aislamientos, se analizaron in vitro las actividades de amilasa, celulasa, pectinasa, proteasa, lacasa, oxidasa extracelular, peroxidasa, citocromo oxidasa, fosfatasa, esterasa y tirosinasa. Las principales especies aisladas en las hojas senescentes fueron Alternaria alternata, Cladosporium cladosporioides, Epicoccum nigrum, Phialophora grupo hoffmannii y Rhodotorula aurantiaca. Las especies dominantes en la hojarasca fueron Hormonema prunorum, Mortierella ramanniana var. angulispora, Penicillium para-herquei y Trichoderma polysporum. El mayor potencial enzimático lo exhibieron Moniliales y micelios estériles, mientras el menor Sphaeropsidales y levaduras. Las especies más activas fueron Alternaria alternata, Cladosporium cladosporioides, Hormonema prunorum y Phialophora malorum. Las actividades de celulasa y amilasa fueron las más importantes. De las enzimas ligninolíticas, oxidasa extracelular y peroxidasa presentaron los más elevados potenciales enzimáticosThe seasonal variation and enzymatic potential of microfungi isolated from senescent leaves and leaf litter of Nothofagus pumilio was studied. The study was performed in a N

  8. Estudio comparativo del crecimiento y la ramificación de brotes anuales en dos especies de Nothofagus (Nothofagaceae y en híbridos inter-específicos Comparative study of annual shoot growth and branching in two species of Nothofagus (Nothofagaceae and inter-specific hybrids

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    Cristian Torres

    2009-12-01

    Full Text Available Las ramas principales y secundarias se diferencian en mayor o menor medida según las especies, lo cual puede observarse en base al crecimiento primario de los brotes que las originan. En ejemplares de vivero juveniles-adultos de Nothofagus obliqua, N. nervosa e híbridos entre ambas especies, se compararon la dinámica de alargamiento, el tamaño y la morfología de dos brotes distales de ramas principales: uno que continúa el alargamiento de la rama principal y el otro que inicia una rama secundaria. En N. alpina y en híbridos, los dos brotes más distales se diferencian más que en N. obliqua. A pesar de la homogeneidad ambiental en el vivero y el origen geográfico común para los ejemplares de N. nervosa y los híbridos, hubieron diferencias fenológicas y morfológicas entre estas entidades. La duración y tasa de alargamiento y la longitud final de los brotes fueron altamente variables en cada entidad. Las variaciones entre entidades en la diferenciación de ejes podrían indicar diferencias en sus capacidades de uso del espacio circundante. La diferenciación entre ramas principales y secundarias se iniciaría en el estado de yema. La variación intra-específica fenológica y morfológica es útil para programas de selección artificial de individuos.Main and secondary branches are more or less differentiated according to the species and this could be observed during the primary growth of the shoots that produce them. In young-adult trees of Nothofagus obliqua, N. nervosa and hybrids between them growing in a common garden, growth dynamics, size and morphology were compared between two distal shoots produced by main branches: one of these shoots continued the extension of the main branch whereas the other initiated a secondary branch. The two distal shoots differed from each other more notably in N. nervosa and in the hybrids than in N. obliqua. Despite the environmental homogeneities at the nursery and the common geographic origin of

  9. Influencias de las variaciones en el clima y en la concentración de C0(2 sobre el crecimiento de Nothofagus pumilio en la Patagonia Influences of climatic and C0(2 concentration changes on radial growth oí Nothofagus pumilio in Patagonia

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    ANA M SRUR

    2008-06-01

    Full Text Available El objetivo de este trabajo fue evaluar las relaciones entre las variaciones en el clima y en la concentración de C0(2 durante el siglo XX con el crecimiento radial y la eficiencia en el uso del agua en los bosques de Nothofagus pumilio a lo largo de un gradiente altitudinal, en El Chaltén (49°22' S, Santa Cruz, Argentina. Se empleó una combinación de técnicas dendrocronológicas e isotópicas. Los patrones de crecimiento radial a lo largo del gradiente altitudinal reflejan las tendencias climáticas registradas en la zona durante el siglo XX. El crecimiento de los árboles ubicados en el límite superior muestra una tendencia positiva en respuesta al incremento regional de las temperaturas. Por el contrario, los bosques en contacto con la estepa patagónica presentan, en respuesta a una intensificación del déficit hídrico, una tendencia negativa de crecimiento durante el siglo pasado. Los árboles creciendo en bosques mésicos ubicados en alturas intermedias muestran una tendencia levemente negativa no significativa. Los valores de 6(13C reflejan en qué medida el contenido de humedad en el suelo regula en forma diferencial los procesos de conductancia estomática y tasa fotosintética a lo largo del gradiente altitudinal. En sitios donde el déficit hídrico varía desde leve a muy marcado, la eficiencia intrínseca en el uso del agua (EIUA parece estar influenciada por la disponibilidad de agua en el suelo. La relación entre la EIUA y las variables climáticas es más clara en sitios con reducido estrés hídrico. En sitios secos, el estrés hídrico muy marcado reduciría la tasa fotosintética en grado tal que el crecimiento no podría ser compensado por el aumento en EIUA. En contraste con el concepto tradicional en dendrocronología que postula una relación más estrecha entre el crecimiento radial y las variaciones climáticas en los bosques ecotonales, los valores isotópicos de 6(13C representan más claramente las

  10. Micro-environmental changes induced by shape and size of forest openings: effects on Austrocedrus chilensis and Nothofagus dombeyi seedlings performance in a Pinus contorta plantation of Patagonia, Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Pafundi, L.; Urretavizcaya, M.F.; Defosse, G.E.

    2016-07-01

    Aim of the study: to analyze, within a Pinus contorta plantation, the effects of artificially created small rectangular and small medium circular canopy gaps on: i) photosynthetic active radiation (PAR), and soil temperature and moisture, and ii) survival and growth of planted Austrocedrus chilensis and Nothofagus dombeyi seedlings, species which formerly composed the natural forest of the area. Study area: A 2 ha stand of a Pinus contorta stand in Los Alerces National Park, Argentina (42°43’S, 71°43’W, 490 m.a.s.l.). Material and methods: The Pinus contorta stand was 25 yr old, 22 m height and 26 cm DBH, presenting 1000 trees ha-1 of density and 53 m2 ha-1 of basal area. In 2009, rectangular and circular gaps were created within the stand and then seedlings were planted. During two growing seasons (2010-2011 and 2011-2012), PAR, soil temperature and moisture were measured in gaps and understory (control), and seedling survival and growth in gaps. Main results: During both seasons, soil temperature did not differ among gaps and control, whereas PAR and soil moisture were lower in control than in gaps. Seedling survival was high in all gaps regardless of species and season. Seedlings showed higher diameter growth in rectangular than in circular gaps. Research highlights: Austrocedrus chilensis and N. dombeyi seedlings survival is high and their growth slightly affected, when planted in differently-sized canopy gaps within a Pinus contorta plantation in Patagonia. However, other gap sizes and stand densities should be tested before recommending which one shows better results for reconverting monocultures into former native forests. Abbreviations used: PAR (Photosynthetic Active Radiation); DBH (Diameter at Breast Height); INTA (Argentinean Institute of Agricultural Technology); IFONA (Argentinean Forest Institute). (Author)

  11. The influence of canopy-layer composition on understory plant diversity in southern temperate forests

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    Luciana Mestre

    2017-05-01

    Full Text Available Background Understory plants represents the largest component of biodiversity in most forest ecosystems and plays a key role in forest functioning. Despite their importance, the influence of overstory-layer composition on understory plant diversity is relatively poorly understood within deciduous-evergreen broadleaved mixed forests. The aim of this work was to evaluate how tree overstory-layer composition influences on understory-layer diversity in three forest types (monospecific deciduous Nothofagus pumilio (Np, monospecific evergreen Nothofagus betuloides (Nb, and mixed N. pumilio-N. betuloides (M forests, comparing also between two geographical locations (coast and mountain to estimate differences at landscape level. Results We recorded 46 plant species: 4 ferns, 12 monocots, and 30 dicots. Canopy-layer composition influences the herb-layer structure and diversity in two different ways: while mixed forests have greater similarity to evergreen forests in the understory structural features, deciduous and mixed were similar in terms of the specific composition of plant assemblage. Deciduous pure stands were the most diverse, meanwhile evergreen stands were least diverse. Lack of exclusive species of mixed forest could represent a transition where evergreen and deciduous communities meet and integrate. Moreover, landscape has a major influence on the structure, diversity and richness of understory vegetation of pure and mixed forests likely associated to the magnitude and frequency of natural disturbances, where mountain forest not only had highest herb-layer diversity but also more exclusive species. Conclusions Our study suggests that mixed Nothofagus forest supports coexistence of both pure deciduous and pure evergreen understory plant species and different assemblages in coastal and mountain sites. Maintaining the mixture of canopy patch types within mixed stands will be important for conserving the natural patterns of understory plant

  12. Similar variation in carbon storage between deciduous and evergreen treeline species across elevational gradients.

    Science.gov (United States)

    Fajardo, Alex; Piper, Frida I; Hoch, Günter

    2013-08-01

    The most plausible explanation for treeline formation so far is provided by the growth limitation hypothesis (GLH), which proposes that carbon sinks are more restricted by low temperatures than by carbon sources. Evidence supporting the GLH has been strong in evergreen, but less and weaker in deciduous treeline species. Here a test is made of the GLH in deciduous-evergreen mixed species forests across elevational gradients, with the hypothesis that deciduous treeline species show a different carbon storage trend from that shown by evergreen species across elevations. Tree growth and concentrations of non-structural carbohydrates (NSCs) in foliage, branch sapwood and stem sapwood tissues were measured at four elevations in six deciduous-evergreen treeline ecotones (including treeline) in the southern Andes of Chile (40°S, Nothofagus pumilio and Nothofagus betuloides; 46°S, Nothofagus pumilio and Pinus sylvestris) and in the Swiss Alps (46°N, Larix decidua and Pinus cembra). Tree growth (basal area increment) decreased with elevation for all species. Regardless of foliar habit, NSCs did not deplete across elevations, indicating no shortage of carbon storage in any of the investigated tissues. Rather, NSCs increased significantly with elevation in leaves (P treeline species are sink limited when faced with decreasing temperatures. Despite the overall higher requirements of deciduous tree species for carbon storage, no indication was found of carbon limitation in deciduous species in the alpine treeline ecotone.

  13. Seasonal patterns of bole water content in old growth Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco)

    Science.gov (United States)

    Large, old conifer trees in the Pacific Northwest (PNW), USA purportedly ameliorate the effects of seasonal summer drought by drawing down the water content of bole tissues over the summer months and refilling during the winter. Continuous monitoring of bole relative water conten...

  14. FIRE RESISTANCE OF DOUGLAS FIR [Pseudotsuga menziesii (Mirb. Franco] WOOD TREATED WITH SOME CHEMICALS

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    M. Kemal YALINKILIÇ

    1998-02-01

    Full Text Available Combustible properties of treated douglas wood specimens and fire-retardancy of some preservatives were tested in this study. Crib test of ASTM E 160-150 was followed. Results indicated that, aqueous solutions of boric acid (BA, borax (Bx (Na2BO7 10H2O or BA + Bx mixture (7: 3, w: w had fire retardant efficacy (FRE over untreated wood and reduced the combustibility of vinil monomers (Styrene and methylmetacrylate which were applied as secondary treatment.

  15. Growth and morphogenesis of shoot initials of Douglas fir, Pseudotsuga menziesii (Mirb.) Franco, in vitro

    NARCIS (Netherlands)

    Evers, P.W.

    1984-01-01

    An optimalized method of micropropagation of Douglas fir is described. Seasonal changes were found in optima for nitrate and sucrose in the medium and in the optimum for the light intensity during the culture of shoot initials. Differences in morphogenesis were obtained from shoot initials that had

  16. Breeding graft-compatible Douglas-fir rootstocks (Pseudotsuga menziesii (Mirb.) Franco).

    Science.gov (United States)

    D.L. Copes

    1999-01-01

    A study encompassing 24 years was conducted to determine if a breeding program could produce highly graft-compatible rootstocks. Twenty-seven trees of apparent high graft compatibility were selected and crossed to produce 226 control-pollinated families. Seedlings were grown, field planted, and grafted with test scions. Graft unions from field tests were evaluated...

  17. High gellan gum concentration and secondary somatic embryogenesis: two key factors to improve somatic embryo development in Pseudotsuga menziesii [Mirb.

    Czech Academy of Sciences Publication Activity Database

    Lelu-Walter, M.A.; Gautier, J.; Eliášová, Kateřina; Sanchez, L.; Teyssier, C.; Lomenech, A. M.; Le Metté, C.; Hargreaves, R.; Trontin, J.F.; Reeves, G.

    2018-01-01

    Roč. 132, č. 1 (2018), s. 137-155 ISSN 0167-6857 Institutional support: RVO:61389030 Keywords : Cell density * Cleavage polyembryony * Douglas-fir * Embryogenic potential * Protein pattern * Vegetative propagation Subject RIV: EF - Botanics OBOR OECD: Plant sciences, botany Impact factor: 2.002, year: 2016

  18. Estimation of population structure in coastal Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco var. menziesii] using allozyme and microsatellite markers

    Science.gov (United States)

    Konstantin V. Krutovsky; John Bradley St. Clair; Robert Saich; Valerie D. Hipkins; David B. Neale

    2009-01-01

    Characterizing population structure using neutral markers is an important first step in association genetic studies in order to avoid false associations between phenotypes and genotypes that may arise from nonselective demographic factors. Population structure was studied in a wide sample of approximately 1,300 coastal Douglas-fir [Pseudotsuga menziesii...

  19. Restos lignocelulósicos de gran tamaño (necromasa en un bosque templado de antiguo crecimiento del sur de Chile

    Directory of Open Access Journals (Sweden)

    Carlos Belezaca Pinargote

    2015-11-01

    Full Text Available Los restos lignocelulósicos de gran tamaño (RLC, constituyen la necromasa en ambientes boscosos, y cumplen variadas funciones ecosistémicas. Se evaluó el volumen, necromasa, y estados de descomposición de RLC muertos, en un bosque templado de antiguo crecimiento (BTAC dentro del Parque Nacional Puyehue, Centro-Sur de Chile. En 10 parcelas de 900 m2, se cuantificó los RLC (≥ 10 cmϕ, cuya necromasa se clasificó empleando una escala de cinco categorías/estados de descomposición (1= menor degradación y 5= mayor degradación. Se encontró 632 m3 ha-1 de madera muerta (= 231,5 Mg ha-1 de necromasa, representados principalmente por Nothofagus betuloides (95,2%, siendo los troncos (52,7%y ramas (35%, las estructuras vegetales más representativas (554,3 m3 ha-1≈ 203 Mg h-1. Estos resultados demuestran que los BTAC del sur de Chile son importantes reservas de litera leñosa gruesa, que contribuye a la biogeoquímica de estos complejos y remotos ecosistemas.

  20. Dendroecological analysis of a Fitzroya cupressoides and a Nothofagus nitida stand in the Cordillera Pelada, Chile

    Science.gov (United States)

    Margaret S. Devall; Bernard R. Parresol; Juan J. Armesto

    1998-01-01

    Lumbering of Fitzroya cupressoides in Chile began in 1599 and continued until 1976, when the species was declared a national monument and cutting of live trees was prohibited. Today, F. cupressoides is threatened; many of the remaining stands in the coastal range appear to be declining, with a predominance of standing dead stems and patchy, sparse regeneration. The...

  1. Organic matter characterization and decomposition dynamics in sub-Antarctic streams impacted by invasive beavers Caracterización de la materia orgánica y la dinámica de descomposición en arroyos subantárticos impactados por castores invasores

    Directory of Open Access Journals (Sweden)

    Erica Ulloa

    2012-11-01

    Full Text Available Despite being a relatively remote and well conserved area, the sub-Antarctic ecoregion faces pressing global threats from climate change, the ozone hole and introduced species. Its freshwater ecosystems are one of the least studied components of this biome, but they are known to confront a host of invasive taxa including trout and beavers. We set out to understand the basic characterization and dynamics of organic matter processing and decomposition in sub-Antarctic streams under natural forest (NF conditions and in ponds constructed by North American beavers (Castor canadensis (BP. We found these streams have a naturally stable benthic organic matter regime throughout the year with a peak in leaf input from Nothofagus pumilio in autumn. Beaver ponds significantly increased the retention of organic matter and caused significantly higher decomposition rates, probably associated with increased density and biomass of Hyalella spp. As expected, leaf decay rates for N. pumilio, a deciduous species, were higher (NF: -0.0028 day- ± 0.0001 SE; BP: -0.0118 day-1 ± 0.0009 SE than N. betuloides (a broad-leaf evergreen (NF: -0.0018 day-1 ± 0.0005 SE; BP: -0.0040 day-1 ± 0.0003 SE. Overall these results indicate that the naturally low decomposition rates (slower than 89% of a global survey of decay rates for these cold, oligotrophic streams are being modified by introduced beavers to resemble more temperate latitudes.A pesar de ser una zona relativamente remota y bien conservado, la ecorregión subantártica se enfrenta a presiones por amenazas globales por el cambio climático, el agujero de ozono y las especies introducidas. Los ecosistemas de agua dulce son uno de los componentes menos estudiados de este bioma, pero se sabe que enfrentan una serie de taxones invasivos como la trucha y los castores. El propósito de este estudio es entender la caracterización básica y dinámica de descomposición de la materia orgánica en arroyos subantárticos de

  2. Long-term monitoring of thinning for silvopastoral purposes in Nothofagus antarctica forests of Tierra del Fuego, Argentina

    Directory of Open Access Journals (Sweden)

    Guillermo Martínez Pastur

    2018-05-01

    Research highlights: Monitoring of thinning for silvopastoral management must include easy and cheap measuring variables, e.g. diameter growth as a proxy for timber production objectives and hemispherical photos (crown cover and radiation as a proxy for pasture production. Long-term monitoring allowed to identify reliable indicators that assist new sustainable management alternatives.

  3. Plant Responses to Increased UV-B Radiation: A Research Project

    Science.gov (United States)

    DAntoni, H. L.; Skiles, J. W.; Armstrong, R.; Coughlan, J.; Daleo, G.; Mayoral, A.; Lawless, James G. (Technical Monitor)

    1994-01-01

    because there is anecdotal evidence of plant damage on the saguaros that has been linked to increased UV radiation, and (3) the forests of Nothofagus spp. and the steppe of Patagonia where the risk of plant damage at 35S is 5% and increases to as much as 15% at 55S due to increased UV-B radiation. Measurements of UV-B radiation impinging on the surface at 55S largely exceed the predicted UV-B radiation values at 50 latitude and 0% ozone depletion. Preliminary HPLC analyses of UV-B absorbing compounds in Nothofagus antartica, N. pumilio, N. betuloides and Rumex sp. in natural conditions show species-specific patterns. The spectrum of N. antartica grown at 38S differs significantly from that of N. antartica in natural conditions in Ushuaia (55S). These results suggest that the selected main area (Patagonia) is appropriate for assessing the problem and its magnitude and that Nothofagus is appropriate for our study.

  4. In the right place at the right time: habitat representation in protected areas of South American Nothofagus-dominated plants after a dispersal constrained climate change scenario.

    Directory of Open Access Journals (Sweden)

    Diego Alarcón

    Full Text Available In order to assess the effects of climate change in temperate rainforest plants in southern South America in terms of habitat size, representation in protected areas, considering also if the expected impacts are similar for dominant trees and understory plant species, we used niche modeling constrained by species migration on 118 plant species, considering two groups of dominant trees and two groups of understory ferns. Representation in protected areas included Chilean national protected areas, private protected areas, and priority areas planned for future reserves, with two thresholds for minimum representation at the country level: 10% and 17%. With a 10% representation threshold, national protected areas currently represent only 50% of the assessed species. Private reserves are important since they increase up to 66% the species representation level. Besides, 97% of the evaluated species may achieve the minimum representation target only if the proposed priority areas were included. With the climate change scenario representation levels slightly increase to 53%, 69%, and 99%, respectively, to the categories previously mentioned. Thus, the current location of all the representation categories is useful for overcoming climate change by 2050. Climate change impacts on habitat size and representation of dominant trees in protected areas are not applicable to understory plants, highlighting the importance of assessing these effects with a larger number of species. Although climate change will modify the habitat size of plant species in South American temperate rainforests, it will have no significant impact in terms of the number of species adequately represented in Chile, where the implementation of the proposed reserves is vital to accomplish the present and future minimum representation. Our results also show the importance of using migration dispersal constraints to develop more realistic future habitat maps from climate change predictions.

  5. Improving lactic acid productivity from wheat straw hydrolysates by membrane integrated repeated batch fermentation under non-sterilized conditions

    DEFF Research Database (Denmark)

    Zhang, Yuming; Chen, Xiangrong; Qi, Benkun

    2014-01-01

    to eliminate the sequential utilization of mixed sugar and feedback inhibition during batch fermentation, membrane integrated repeated batch fermentation (MIRB) was used to improve LA productivity. With MIRB, a high cell density was obtained and the simultaneous fermentation of glucose, xylose and arabinose...

  6. Stand structure and regeneration of harvested Araucaria araucana ...

    African Journals Online (AJOL)

    Stand structure and regeneration of harvested Araucaria araucana–Nothofagus stands in central Chile. Rafael M Navarro-Cerrillo, Fernando Olave, Francisco Moreno, Sergio de Miguel, Margarita Clemente ...

  7. Notes on bolete taxonomy

    NARCIS (Netherlands)

    Singer, R.

    1973-01-01

    Newly discovered mycorrhizal relationships of boletes (with Nothofagus, Shorea, Quercus humboldtii, Alnus jorullenses, Eucalyptus, and Leptospermum) are discussed. Type studies on Fistulinella, Boletus granulatus var. capricollensis, Boletogaster, and Gastroboletus are reported. The following new

  8. Litterfall, litter decomposition and nitrogen mineralization in old-growth evergreen and secondary deciduous Nothofagus forests in south-central Chile Aporte, descomposición de hojarasca y mineralización de nitrógeno en bosques siempreverdes de antiguo crecimiento y bosques secundarios deciduos, centro-sur de Chile

    Directory of Open Access Journals (Sweden)

    JEROEN STAELENS

    2011-03-01

    Full Text Available South Chilean forest ecosystems represent one of the largest areas of old-growth temperate rainforests remaining in the Southern hemisphere and have a high ecological value, but suffer from deforestation, invasion by exotic species, fragmentation, and increasing atmospheric nitrogen (N deposition. To support sustainable forest management, more knowledge is required on nutrient cycling of these ecosystems. Therefore, a descriptive study of nutrient dynamics was done in four Valdivian rainforests in the lower Andes range of south Chile: old-growth and altered evergreen stands and unmanaged and managed secondary deciduous stands. Time series were measured for (i mass (four year and nutrient content (N, K, Ca, and Mg; one year of litterfall, (ii decomposition and nutrient dynamics (N, C, K, Ca, Mg, and P; one year of leaf litter and Saxegothaea conspicua bark litter, and (iii in situ topsoil net N mineralization (one year. Litterfall in the four stands ranged from 3.5 to 5.8 ton ha-1 yr-1, was temporarily lower in the managed than in the unmanaged deciduous stand and had a different seasonality in the evergreen stands than in the deciduous stands. Leaf litter decomposed faster (on average 32 % mass loss after one year than bark litter (8 % but without significant differences between leaf litter types. Net N in evergreen leaf litter decreased during decomposition but increased in deciduous leaf litter. Net soil N mineralization was fastest in the pristine evergreen stand, intermediate in the deciduous stands and slowest in the altered evergreen forest. Given the absence of replicated stands, the definite impact of forest type or management regime on the internal nutrient cycling cannot be demonstrated. Nevertheless, the results suggest that management can affect nutrient turnover by altering species composition and forest structure, while recent (five years selective logging in secondary deciduous forest did not affect litter decomposition or N mineralization rates in the present study.Los ecosistemas forestales del sur de Chile presentan un gran valor ecológico pues constituyen una de las mayores áreas del hemisferio Sur con existencias de bosques templados lluviosos. Están sometidos a procesos de deforestación, invasión de especies exóticas, fragmentación e incremento de depositación de nitrógeno (N atmosférico. Para apoyar su manejo sustentable se requiere de mayor conocimiento en el ciclo de nutrientes de estos ecosistemas. Se estudia la dinámica de nutrientes en cuatro sitios de bosques lluviosos valdivianos de la precordillera de los Andes, centro-sur de Chile: un bosque siempreverde de antiguo crecimiento prístino y otro alterado, un bosque caducifolio secundario con manejo silvícola y otro sin. Durante el período octubre 2002 -septiembre 2006, se estimaron (i masa de la hojarasca (cuatro años y contenido de nutrientes de la hojarasca (un año, (ii descomposición y dinámica de nutrientes de hojarasca (un año y de la corteza de Saxegothaea conspicua, y (iii mineralización neta de nitrógeno (N-min en el suelo in situ (un año. El aporte de hojarasca en los cuatro sitios fluctúa desde 3.5 hasta 5.8 ton ha-1 año-1, y es temporalmente menor en bosque caducifolio manejado, respecto del caducifolio sin manejo. Además, presentan una estacionalidad en los siempreverdes que es diferente, respecto de los deciduos. La hojarasca se descompone más rápidamente (promedio 32 % pérdida de masa después de un año que la corteza (8 %, pero no se presentaron diferencias significativas en la hojarasca. El N neto en la hojarasca de los bosques siempreverdes disminuye durante la descomposición, pero se incrementa en la hojarasca de los deciduos. La N-mineralización neta del suelo fue completa en el bosque siempreverde prístino, intermedia en los bosques deciduos y el más baja en el bosque siempreverde alterado. Dada la ausencia de réplicas en las parcelas, no puede ser demostrado el impacto definido del tipo de bosque o régimen de manejo en el ciclo interno de nutrientes. Sin embargo, los resultados sugieren que el manejo silvícola puede afectar el reciclaje de nutrientes por la alteración en la composición de especies y estructura del bosque, aun cuando en el bosque secundario deciduo una extracción selectiva de madera en tiempo reciente (cinco años, no afecta la descomposición de la hojarasca o los montos de mineralización del nitrógeno.

  9. Estimating seed crops of conifer and hardwood species

    Science.gov (United States)

    Philip M. McDonald

    1992-01-01

    Cone, acorn, and berry crops of ponderosa pine (Pinus ponderosa Dougl. ex Laws. var. ponderosa), sugar pine (Pinus lambertiana Dougl.), Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), California white fir (Abies concolor var. lowiana (Gord...

  10. Basal area growth, carbon isotope discrimination, and intrinsic water use efficiency after fertilization of Douglas-fir in the Oregon Coast Range

    Science.gov (United States)

    Many hectares of intensively managed Douglas-fir (Pseudotsuga menziesii Mirb. Franco) stands in western North America are fertilized with nitrogen to increase growth rates. Understanding the mechanisms of response facilitates prioritization of stands for treatment. The objective ...

  11. NEEDLE ANATOMY CHANGES WITH INCREASING TREE AGE IN DOUGLAS FIR

    Science.gov (United States)

    Morphological differences between old growth and sapling (Pseudotsuga menziesii, (Mirb.) Franco) Douglas fir trees may extend to differences in needle anatomy. We used microscopy with image analysis to compare and quantify anatomical parameters in cross-sections of previous year...

  12. Wellington Quaternary palynology

    International Nuclear Information System (INIS)

    Harris, W.F.; Mildenhall, D.C.

    1984-01-01

    Pollen samples from a profile at Taita indicate a grassland environment prior to and immediately after the deposition of the Aokautere Ash (Kawakawa Tephra) approximately 21,000 years B.P. This grassland gradually gave way to a Nothofagus menziesii montane forest followed by an abrupt change to a N. ''Fusca'' group dominant forest which continues to the top of the section. The top few centimetres of the profile may have been deposited in post-European time. The abrupt change in the species of beech represents an unconformity of unknown duration. Pollen samples from a number of profiles at Mangaroa (Wallaceville Swamp) indicate a change from a cool environment (Gramineae plus Phyllocladus) through successive phases of Nothofagus menziesii, Podocarpus species, Dacrydium cupressinum to Nothofagus ''fusca'' group close to the present day. These results are presented in an historical context based on notes left by Dr W.F. Harris, supplemented with additional data by the junior author

  13. Effects of the iron oxide nanoparticle Molday ION Rhodamine B on the viability and regenerative function of neural stem cells: relevance to clinical translation

    Directory of Open Access Journals (Sweden)

    Umashankar A

    2016-04-01

    Full Text Available Abhishek Umashankar,1,2,* Mandi J Corenblum,1,* Sneha Ray,1,2,* Michel Valdez,3 Eriko S Yoshimaru,3 Theodore P Trouard,3,4 Lalitha Madhavan1,4 1Department of Neurology, 2Neuroscience and Cognitive Science Undergraduate Program, Undergraduate Biology Research Program, 3Department of Biomedical Engineering, 4Evelyn F McKnight Brain Institute, University of Arizona, Tucson, AZ, USA *These authors contributed equally to this work Abstract: An essential component of developing successful neural stem cell (NSC-based therapies involves the establishment of methodologies to noninvasively monitor grafted NSCs within brain tissues in real time. In this context, ex vivo labeling with ultrasmall superparamagnetic iron oxide (USPIO particles has been shown to enable efficient tracking of transplanted NSCs via magnetic resonance imaging (MRI. However, whether and how USPIO labeling affects the intrinsic biology of NSCs is not thoroughly understood, and remains an active area of investigation. Here, we perform a comprehensive examination of rat NSC survival and regenerative function upon labeling with the USPIO, Molday ION Rhodamine B (MIRB, which allows for dual magnetic resonance and optical imaging. After optimization of labeling efficiency, two specific doses of MIRB (20 and 50 µg/mL were chosen and were followed for the rest of the study. We observed that both MIRB doses supported the robust detection of NSCs, over an extended period of time in vitro and in vivo after transplantation into the striata of host rats, using MRI and post hoc fluorescence imaging. Both in culture and after neural transplantation, the higher 50 µg/mL MIRB dose significantly reduced the survival, proliferation, and differentiation rate of the NSCs. Interestingly, although the lower 20 µg/mL MIRB labeling did not produce overtly negative effects, it increased the proliferation and glial differentiation of the NSCs. Additionally, application of this dose also changed the

  14. Effects of the iron oxide nanoparticle Molday ION Rhodamine B on the viability and regenerative function of neural stem cells: relevance to clinical translation.

    Science.gov (United States)

    Umashankar, Abhishek; Corenblum, Mandi J; Ray, Sneha; Valdez, Michel; Yoshimaru, Eriko S; Trouard, Theodore P; Madhavan, Lalitha

    2016-01-01

    An essential component of developing successful neural stem cell (NSC)-based therapies involves the establishment of methodologies to noninvasively monitor grafted NSCs within brain tissues in real time. In this context, ex vivo labeling with ultrasmall superparamagnetic iron oxide (USPIO) particles has been shown to enable efficient tracking of transplanted NSCs via magnetic resonance imaging (MRI). However, whether and how USPIO labeling affects the intrinsic biology of NSCs is not thoroughly understood, and remains an active area of investigation. Here, we perform a comprehensive examination of rat NSC survival and regenerative function upon labeling with the USPIO, Molday ION Rhodamine B (MIRB), which allows for dual magnetic resonance and optical imaging. After optimization of labeling efficiency, two specific doses of MIRB (20 and 50 μg/mL) were chosen and were followed for the rest of the study. We observed that both MIRB doses supported the robust detection of NSCs, over an extended period of time in vitro and in vivo after transplantation into the striata of host rats, using MRI and post hoc fluorescence imaging. Both in culture and after neural transplantation, the higher 50 μg/mL MIRB dose significantly reduced the survival, proliferation, and differentiation rate of the NSCs. Interestingly, although the lower 20 μg/mL MIRB labeling did not produce overtly negative effects, it increased the proliferation and glial differentiation of the NSCs. Additionally, application of this dose also changed the morphological characteristics of neurons and glia produced after NSC differentiation. Importantly, the transplantation of NSCs labeled with either of the two MIRB doses upregulated the immune response in recipient animals. In particular, in animals receiving the 50 μg/mL MIRB-labeled NSCs, this immune response consisted of an increased number of CD68(+)-activated microglia, which appeared to have phagocytosed MIRB particles and cells contributing to an

  15. SIRB, sans iron oxide rhodamine B, a novel cross-linked dextran nanoparticle, labels human neuroprogenitor and SH-SY5Y neuroblastoma cells and serves as a USPIO cell labeling control.

    Science.gov (United States)

    Shen, Wei-Bin; Vaccaro, Dennis E; Fishman, Paul S; Groman, Ernest V; Yarowsky, Paul

    2016-05-01

    This is the first report of the synthesis of a new nanoparticle, sans iron oxide rhodamine B (SIRB), an example of a new class of nanoparticles. SIRB is designed to provide all of the cell labeling properties of the ultrasmall superparamagnetic iron oxide (USPIO) nanoparticle Molday ION Rhodamine B (MIRB) without containing the iron oxide core. MIRB was developed to label cells and allow them to be tracked by MRI or to be manipulated by magnetic gradients. SIRB possesses a similar size, charge and cross-linked dextran coating as MIRB. Of great interest is understanding the biological and physiological changes in cells after they are labeled with a USPIO. Whether these effects are due to the iron oxide buried within the nanoparticle or to the surface coating surrounding the iron oxide core has not been considered previously. MIRB and SIRB represent an ideal pairing of nanoparticles to identify nanoparticle anatomy responsible for post-labeling cytotoxicity. Here we report the effects of SIRB labeling on the SH-SY5Y neuroblastoma cell line and primary human neuroprogenitor cells (hNPCs). These effects are contrasted with the effects of labeling SH-SY5Y cells and hNPCs with MIRB. We find that SIRB labeling, like MIRB labeling, (i) occurs without the use of transfection reagents, (ii) is packaged within lysosomes distributed within cell cytoplasm, (iii) is retained within cells with no loss of label after cell storage, and (iv) does not alter cellular viability or proliferation, and (v) SIRB labeled hNPCs differentiate normally into neurons or astrocytes. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  16. A pollen-based record of late glacial-Holocene climatic variability in the southern lake district, Chile

    NARCIS (Netherlands)

    Vargas-Ramirez, L.; Roche, E.; Gerrienne, P.; Hooghiemstra, H.

    2008-01-01

    A pollen record from Puyehue area (40°S; 72°W) in the southern Lake District, Chile, indicates that prior to 13,410 14C yr BP (ca. 16,500-15,200 cal yr BP), cold resistant and hygrophilous vegetation, particularly Nothofagus forest and myricaceous vegetation, covered the area. From ca. 15,000 cal yr

  17. Potential biotechnological application of mycorrhizas and yeasts associated with Nathofagus nervosa (Rauli)

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, N.; Fontenla, S.; Gallo, L.; Marchelli, P.

    2009-07-01

    Nothofagus nervosa is an ecologically and economically important species of south American temperate forests. In Argentina, it has a reduced natural distribution area due to over exploitation, overgrazing and forest fires. This critical situation led to the implementation of conservation and domestication programs. (Author)

  18. NUEVA LOCALIDAD GEOGRAFICA PARA BERBERIS NEGERIANA TISCHLER (BERBERIDACEAE) EN LA PROVINCIA DE ARAUCO, REGION DEL BIO-BIO, CHILE

    OpenAIRE

    Gómez, Persy; Belov, Michail; San Martín, José

    2008-01-01

    This note reports the finding of a population of Berberis negeriana Tischler (Berberidaceae), in the province of Arauco, Bío-Bío Region (37°42'17" S y 73°19'43" W) in the center south of Chile. The population was found between Nothofagus obliqua and species of the Valdiviano Forest.

  19. Subantarctic forest ecology : case study of a conifer-broadleaved stand in Patagonia, Argentina

    NARCIS (Netherlands)

    Dezzotti, A.

    2000-01-01

    In the temperate rainforests of southern South America, the tree genus Nothofagus (Nothofagaceae) is the dominant in extension and abundance on zonal soils at different latitudes and altitudes, as well as on intrazonal (e.g., wetlands) and azonal soils (e.g., morrenic

  20. An experimental approach to explain the southern Andes elevational treeline.

    Science.gov (United States)

    Fajardo, Alex; Piper, Frida I

    2014-05-01

    • The growth limitation hypothesis (GLH) is the most accepted mechanistic explanation for treeline formation, although it is still uncertain whether it applies across taxa. The successful establishment of Pinus contorta--an exotic conifer species in the southern hemisphere--above the Nothofagus treeline in New Zealand may suggest a different mechanism. We tested the GLH in Nothofagus pumilio and Pinus contorta by comparing seedling performance and carbon (C) balance in response to low temperatures.• At a southern Chilean treeline, we grew seedlings of both species 2 m above ground level, to simulate coupling between temperatures at the meristem and in the air (colder), and at ground level, i.e., decoupling air temperature (relatively milder). We recorded soil and air temperatures as well. After 3 yr, we measured seedling survival and biomass (as a surrogate of growth) and determined nonstructural carbohydrates (NSC).• Nothofagus and Pinus did not differ in survival, which, as a whole, was higher at ground level than at the 2-m height. The root-zone temperature for the growing season was 6.6°C. While biomass and NSC decreased significantly for Nothofagus at the 2-m height compared with ground level (C limitation), these trends were not significant for Pinus• The treeline for Nothofagus pumilio is located at an isotherm that fully matches global patterns; however, its physiological responses to low temperatures differed from those of other treeline species. Support for C limitation in N. pumilio but not in P. contorta indicates that the physiological mechanism explaining their survival and growth at treeline may be taxon-dependent. © 2014 Botanical Society of America, Inc.

  1. Killing tanoak in northwestern California

    Science.gov (United States)

    D. F. Roy

    1956-01-01

    Residual tanoak (Lithocarpus densiflorus (Hook. & Arn.) Rehd.) trees and tanoak sprouts often are an important component of the vegetation which competes with conifer reproduction in northwestern California. Sometimes enough tanoak is present in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) stands to dominate the...

  2. Regeneration in mixed conifer and Douglas-fir shelterwood cuttings in the Cascade Range of Washington.

    Science.gov (United States)

    K.W. Seidel

    1983-01-01

    A survey of shelterwood cuttings in mixed conifer and Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) forests in the Cascade Range in Washington showed that, on the average, shelterwood units were adequately-stocked with a mixture of advance, natural postharvest, and planted reproduction of a number of species. Shelterwood cuttings in the...

  3. Biophysical constraints on leaf expansion in a tall conifer.

    Science.gov (United States)

    Fredrick C. Meinzer; Barbara J. Bond; Jennifer A. Karanian

    2008-01-01

    The physiological mechanisms responsible for reduced extension growth as trees increase in height remain elusive. We evaluated biophysical constraints on leaf expansion in old-growth Douglas-fir (Psuedotsuga menziesii (Mirb.) Franco) trees. Needle elongation rates, plastic and elastic extensibility, bulk leaf water, (L...

  4. Effects of plantation and juvenile spacing on tree and stand development.

    Science.gov (United States)

    J. Harry G. Smith; Donald L. Reukema

    1986-01-01

    The aim of this paper is to summarize current knowledge of effects of initial spacing and respacing of plantations and natural stands on early growth until the time of first commercial entry—for coastal Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco), concentrating on conclusions that can be drawn from the literature and the authors...

  5. Stump-to-truck cable logging cost equations for young-growth douglas-fir

    Science.gov (United States)

    Chris B. LeDoux; Roger D. Fight; Tom L. Ortman

    1986-01-01

    Logging cost simulators and data from logging cost studies have been assembled and converted into a series of equations that can be used to estimate the cost of logging young-growth coastal Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco var. menziesii) in mountainous terrain of the Pacific Northwest. These equations were...

  6. Projected future suitable habitat and productivity of Douglas-fir in western North America

    Science.gov (United States)

    Aaron R. Weiskittel; Nicholas L. Crookston; Gerald E. Rehfeldt

    2012-01-01

    Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) is one of the most common and commercially important species in western North America. The species can occupy a range of habitats, is long-lived (up to 500 years), and highly productive. However, the future of Douglas-fir in western North America is highly uncertain due to the expected changes in climate conditions....

  7. Trapping Douglas-fir beetle (Dendroctonus pseudotsugae) with pheromone baited multiple-funnel traps does not reduce Douglas-fir (Pseudotsuga menziesii) mortality

    Science.gov (United States)

    R.A. Progar; N. Sturdevant; M.J. Rinella

    2010-01-01

    Douglas-fir beetle (Dendroctonus pseudotsugae Hopkins) (DFB) causes considerable mortality to Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) in western North American forests. We evaluated the use of semiochemical-baited multiple-funnel traps for the protection of small, high-value stands of trees, such as those occurring...

  8. Size of Douglas-fir trees in relation to distance from a mixed red alder - Douglas-fir stand

    Science.gov (United States)

    R.E. Miller; D.L. Reukema; T.A. Max

    1993-01-01

    Variation in diameter, height, and stem volume of 57-year-old Douglas-fir(Pseudotsuga menziesii var. menziesii (Mirb.) Franco) was related to distance of these trees from a 27 m wide strip in the same Douglas-fir plantation that had been interplanted with red alder (Alnus rubra Bong.). Within the...

  9. Douglas-fir tussock moth- and Douglas-fir beetle-caused mortality in a ponderosa pine/Douglas-fir forest in the Colorado Front Range, USA

    Science.gov (United States)

    Jose F. Negron; Ann M. Lynch; Willis C. Schaupp; Vladimir Bocharnikov

    2014-01-01

    An outbreak of the Douglas-fir tussock moth, Orgyia pseudotsugata McDunnough, occurred in the South Platte River drainage on the Pike-San Isabel National Forest in the Colorado Front Range attacking Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco. Stocking levels, species composition, and tree size in heavily and lightly defoliated stands were similar. Douglas-fir...

  10. Douglas-fir displays a range of growth responses to temperature, water, and Swiss needle cast in western Oregon, USA

    Science.gov (United States)

    Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) growth in the Pacific Northwest is affected by climatic, edaphic factors and Swiss needle cast (SNC) disease. We examine Douglas-fir growth responses to temperature, dewpoint deficit (DPD), soil moisture, and SNC ...

  11. Multi-decadal establishment for single-cohort Douglas-fir forests

    Science.gov (United States)

    James A. Freund; Jerry F. Franklin; Andrew J. Larson; James A. Lutz

    2014-01-01

    The rate at which trees regenerate following stand-replacing wildfire is an important but poorly understood process in the multi-century development of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and western hemlock (Tsuga heterophylla (Raf.) Sarg.) forests. Temporal patterns of Douglas-fir establishment reconstructed from old-growth forests (>450 year) have...

  12. Simulating fuel treatment effects in dry forests of the western United States: testing the principles of a fire-safe forest

    Science.gov (United States)

    Morris C. Johnson; Maureen C Kennedy; David L. Peterson

    2011-01-01

    We used the Fire and Fuels Extension to the Forest Vegetation Simulator (FFE-FVS) to simulate fuel treatment effects on stands in low- to midelevation dry forests (e.g., ponderosa pine (Pinus ponderosa Dougl. ex. P. & C. Laws.) and Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) of the western United States. We...

  13. The Douglas-fir genome sequence reveals specialization of the photosynthetic apparatus in Pinaceae

    Science.gov (United States)

    David B. Neale; Patrick E. McGuire; Nicholas C. Wheeler; Kristian A. Stevens; Marc W. Crepeau; Charis Cardeno; Aleksey V. Zimin; Daniela Puiu; Geo M. Pertea; U. Uzay Sezen; Claudio Casola; Tomasz E. Koralewski; Robin Paul; Daniel Gonzalez-Ibeas; Sumaira Zaman; Richard Cronn; Mark Yandell; Carson Holt; Charles H. Langley; James A. Yorke; Steven L. Salzberg; Jill L. Wegrzyn

    2017-01-01

    A reference genome sequence for Pseudotsuga menziesii var. menziesii (Mirb.) Franco (Coastal Douglas-fir) is reported, thus providing a reference sequence for a third genus of the family Pinaceae. The contiguity and quality of the genome assembly far exceeds that of other conifer reference genome sequences (contig N50 = 44,136 bp and scaffold N50...

  14. Inheritance of restriction fragment length polymorphisms, random amplified polymorphic DNAs and isozymes in coastal Douglas-fir

    Science.gov (United States)

    K.D. Jermstad; A.M. Reem; J.R. Henifin; N.C. Wheeler; D.B Neale

    1994-01-01

    A total of 225 new genetic loci [151 restriction fragment length polymorphisms (RFLP) and 74 random amplified polymorphic DNAs (RAPD)] in coastal Douglas- fir [Pseudotsuga menziesii (Mirb.) Franco var. menziesii] have been identified using a three-generation outbred pedigree. The Mendelian inheritance of 16 RFLP loci and 29...

  15. SEASONAL PATTERNS OF PHOTOSYNTHESIS IN DOUGLAS FIR SEEDLINGS DURING THE THIRD AND FOURTH YEAR OF EXPOSURE TO ELEVATED CO2 AND TEMPERATURE

    Science.gov (United States)

    We examined the interactive effects of elevated atmospheric CO2 and temperature on seasonal patterns of photosynthesis in Douglas-fir (Psuedotsuga menziesii (Mirb.) Franco) seedlings. Seedlings were grown in sunlit chambers controlled to track either ambient (~400 ppm) CO2 or am...

  16. Simulation of carbon and water budgets of a Douglas-fir forest

    NARCIS (Netherlands)

    Wijk, van M.T.; Dekker, S.C.; Bouten, W.; Kohsiek, W.; Mohren, G.M.J.

    2001-01-01

    The forest growth/hydrology model FORGRO–SWIF, consisting of a forest growth and a soil water model, was applied to quantify the inter-annual variability of the carbon and water budgets of a Douglas-fir forest (Pseudotsuga menziessii (Mirb.) Franco) in The Netherlands. With these budgets, the water

  17. Developmental decline in height growth in Douglas-fir.

    Science.gov (United States)

    Barbara J. Bond; Nicole M. Czarnomski; Clifton Cooper; Michael E. Day; Michael S. Greenwood

    2007-01-01

    The characteristic decline in height growth that occurs over a tree's lifespan is often called "age-related decline." But is the reduction in height growth in aging trees a function of age or of size? We grafted shoot tips across different ages and sizes of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees to determine whether...

  18. Levels-of-growing-stock cooperative study in Douglas-fir: report no. 19—The Iron Creek study, 1966–2006.

    Science.gov (United States)

    Robert O. Curtis; David D. Marshall

    2009-01-01

    This report documents the history and results of the Iron Creek installation of the cooperative Levels-of-Growing-Stock (LOGS) study in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), over the period 1966–2006 (ages 19 to 59). This is a 1949 plantation on an excellent site, and is one of nine installations in the study. Results are generally...

  19. Levels-of-growing-stock cooperative study in Douglas-fir: report no. 18--Rocky Brook, 1963-2006.

    Science.gov (United States)

    Robert O. Curtis; David D. Marshall

    2009-01-01

    This report documents the history and results of the Rocky Brook installation of the cooperative levels-of-growing-stock (LOGS) study in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), over the 41-year period 1965 to 2006. This 1938 plantation is one of the two site-IV installations among the nine installations in the study. Much public...

  20. Growth of bear-damaged trees in a mixed plantation of Douglas-fir and red alder.

    Science.gov (United States)

    Richard E. Miller; Harry W. Anderson; Donald L. Reukema; Timothy A. Max

    2007-01-01

    Incidence and effects of tree damage by black bear (Ursus americanus altifrontalis) in a 50-year-old, coast Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) plantation are described. Bears girdled or partially girdled 35 dominant or codominant Douglas-fir trees per acre, but only in that...

  1. Effects of bear damage on Douglas-fir lumber recovery

    Science.gov (United States)

    Eini C. Lowell; Dennis Dykstra; George McFadden

    2009-01-01

    Bear activily resulting in injury to Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) trees has been documented as early as the mid-1850s in the Pacific Northwest. The study reported in this article was designed to help managers decide whether the common practice of removing the damaged but potentially valuable butt section of the bottom log and...

  2. Changes in wood product proportions in the Douglas-fir region with respect to size, age, and time.

    Science.gov (United States)

    R.A. Monserud; X. Zhou

    2007-01-01

    We examine both the variation and the changing proportions of different wood products obtained from trees and logs in the Douglas-fir region of the Northwestern United States. Analyses are based on a large product recovery database covering over 40 years of recovery studies; 13 studies are available for Douglas-fir (Pseudotsuga menziesii (Mirb.)...

  3. Short-day treatment alters Douglas-fir seedling dehardening and transplant root proliferation at varying rhizosphere temperatures

    Science.gov (United States)

    Douglass F. Jacobs; Anthony S. Davis; BArrett C. Wilson; R. Kasten Dumroese; Rosa C. Goodman; K. Francis Salifu

    2008-01-01

    We tested effects of shortened day length during nursery culture on Douglis-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) seedling development at dormancy release. Seedlings from a 42 N source were grown either under ambient photoperiods (long-day (LD)) or with a 28 day period of 9 h light: 15 h dark photoperiods (short...

  4. Growth and yield of all-aged Douglas-fir -- western hemlock forest stands: a matrix model with stand diversity effects.

    Science.gov (United States)

    Jingjing Liang; Joseph Buonglorno; Robert A. Monserud

    2005-01-01

    A density-dependent matrix model was developed for Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) -- western hemlock (Tsuga heterophylla (Raf.) Sarg.) forest stands in the Pacific Northwest of the United States. The model predicted the number and volume of trees for 4 species groups and 19 diameter classes. The parameters...

  5. Estimating tree biomass, carbon, and nitrogen in two vegetation control treatments in an 11-year-old Douglas-fir plantation on a highly productive site

    Science.gov (United States)

    Warren D. Devine; Paul W. Footen; Robert B. Harrison; Thomas A. Terry; Constance A. Harrington; Scott M. Holub; Peter J. Gould

    2013-01-01

    We sampled trees grown with and without competing vegetation control in an 11-year-old Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) plantation on a highly productive site in southwestern Washington to create diameter based allometric equations for estimating individual-tree bole, branch, foliar, and total...

  6. History of fire and Douglas-fir establishment in a savanna and sagebrush-grassland mosaic, southwestern Montana, USA

    Science.gov (United States)

    Emily K. Heyerdahl; Richard F. Miller; Russell A. Parsons

    2006-01-01

    Over the past century, trees have encroached into grass- and shrublands across western North America. These include Douglas-fir trees (Pseudotsuga menziesii (Mirb.) Franco var. glauca (Beissn.) Franco) encroaching into mountain big sagebrush Nutt. ssp. vaseyana (Rydb.) Beetle) from stable islands of savanna in...

  7. Stand-level gas-exchange responses to seasonal drought in very young versus old Douglas-fir forests of the Pacific Northwest, USA

    Science.gov (United States)

    Sonia Wharton; Matt Schroeder; Ken Bible; Matthias Falk; Kyaw Tha Paw U

    2009-01-01

    This study examines how stand age affects ecosystem mass and energy exchange response to seasonal drought in three adjacent Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) forests. The sites include two early seral (ES) stands (0 to 15 years old) and an old-growth (OG) (~450 to 500 years old) forest in the Wind River Experimental Forest,...

  8. Graft union formation in Douglas-fir.

    Science.gov (United States)

    D.L. Copes

    1969-01-01

    Greenhouse-grown Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) graft unions were examined between 2 and 84 days after grafting. Room temperature was maintained at 60-70 F throughout the growing season. In most respects grafts of Douglas-fir followed development patterns previously reported for spruce and pine grafts, but specific differences...

  9. Parental GCA testing: how many crosses per parent?

    Science.gov (United States)

    G.R. Johnson

    1998-01-01

    The impact of increasing the number of crosses per parent (k) on the efficiency of roguing seed orchards (backwards selection, i.e., reselection of parents) was examined by using Monte Carlo simulation. Efficiencies were examined in light of advanced-generation Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) tree improvement programs where...

  10. Some lessons in artificial regeneration from southwestern Oregon.

    Science.gov (United States)

    William I. Stein

    1955-01-01

    Natural reproduction has often proved undependable for restocking cutovers and burns in the mixed-conifer forest types of southwestern Oregon. These types, covering 6,000 square miles of productive forest land in the five southwestern Oregon counties, are composed of many species--principally Douglas fir, Pseudotsuga menziesii (Mirb.) Franco;...

  11. Testing predictions of forest succession using long-term measurements: 100 yrs of observations in the Oregon Cascades

    Science.gov (United States)

    Mark E. Harmon; Robert J. Pabst

    2015-01-01

    Question: Many predictions about forest succession have been based on chronosequences. Are these predictions – at the population, community and ecosystemlevel – consistent with long-termmeasurements in permanent plots? Location: Pseudotsuga menziesii (Mirb.) Franco dominated forest in western Oregon, US.Methods: Over a 100-yr period,...

  12. Height-growth response to climatic changes differs among populations of Douglas-fir: A novel analysis of historic data

    Science.gov (United States)

    Laura P. Leites; Andrew P. Robinson; Gerald E. Rehfeldt; John D. Marshall; Nicholas L. Crookston

    2012-01-01

    Projected climate change will affect existing forests, as substantial changes are predicted to occur during their life spans. Species that have ample intraspecific genetic differentiation, such as Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), are expected to display population-specific growth responses to climate change. Using a mixed-effects modeling approach,...

  13. Growth phenology of coast Douglas-fir seed sources planted in diverse environments

    Science.gov (United States)

    Peter J. Gould; Constance A. Harrington; J. Bradley St. Clair

    2012-01-01

    The timing of periodic life cycle events in plants (phenology) is an important factor determining how species and populations will react to climate change. We evaluated annual patterns of basal-area and height growth of coast Douglas-fir (Pseudotusuga menziesii var. menziesii (Mirb.) Franco) seedlings from four seed sources...

  14. Spatial and population characteristics of dwarf mistletoe infected trees in an old-growth Douglas-fir - western hemlock forest.

    Science.gov (United States)

    David C. Shaw; Jiquan Chen; Elizabeth A. Freeman; David M. Braun

    2005-01-01

    We investigated the distribution and severity of trees infected with western hemlock dwarf mistletoe (Arceuthobium tsugense (Rosendahl) G.N. Jones subsp. tsugense) in an old-growth Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) - western hemlock (Tsuga heterophylla (Raf.) Sarg.)...

  15. DFSIM with economics: A financial analysis option for the DFSIM Douglas-fir simulator.

    Science.gov (United States)

    Roger O. Fight; Judith M. Chittester; Gary W. Clendenen

    1984-01-01

    A modified version of the DFSIM Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) growth and yield simulator, DFSIM WITH ECONOMICS, now has an economics option that allows the user to estimate present net worth at the same time a silvicultural regime is simulated. If desired, the economics option will apply a...

  16. THE KINETICS OF NH(4)+ AND NO3(-) UPTAKE BY DOUGLAS-FIR FROM SINGLE N-SOLUTIONS AND FROM SOLUTIONS CONTAINING BOTH NH(4)+ AND NO3(-)

    NARCIS (Netherlands)

    KAMMINGAVANWIJK, C; PRINS, HBA

    The kinetics of NH4+ and NO3- uptake in young Douglas fir trees (Pseudotsuga menziesii [Mirb.] Franco) were studied in solutions, containing either one or both N species. Using solutions containing a single N species, the V(max) of NH4+ uptake was higher than that of NO3- uptake. The K(m) of NH4+

  17. The influence of weather variation on regional growth of Douglas-fir stands in the U.S. Pacific Northwest.

    Science.gov (United States)

    Charles E. Peterson; Linda S. Heath

    1991-01-01

    In this paper we examine the influence of precipitation and temperature deviations on regional volume growth rates in even aged, onnen.,ed second growth Douglas fir (Pseudotsuga menziesii [Mirb.] Franco) stands. Between 1969 and 1986, average volume growth rates in natural stands of coast Douglas fix in western Washington and Oregon were negatively...

  18. Fine-scale variability in growth-climate relationships of Douglas-fir, North Cascade Range, Washington.

    Science.gov (United States)

    Michael J. Case; David L. Peterson

    2005-01-01

    Information about the sensitivity to climate of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) is valuable because it will allow forest managers to maximize growth, better understand how carbon sequestration may change over time, and better model and predict future ecosystem responses to climatic change. We examined the effects of climatic...

  19. Soil disturbance and 10-year growth response of coast Douglas-fir on nontilled and tilled skid trails in the Oregon Cascades.

    Science.gov (United States)

    Ronald Heninger; William Scott; Alex Dobkowski; Richard Miller; Harry Anderson; Steve Duke

    2002-01-01

    We (i) quantified effects of skidder yarding on soil properties and seedling growth in a portion of western Oregon, (ii) determined if tilling skid trails improved tree growth, and (iii) compared results with those from an earlier investigation in coastal Washington. Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings were hand planted at...

  20. Belowground competition from overstory trees influences Douglas-fir sapling morphology in thinned stands

    Science.gov (United States)

    Warren D. Devine; Timothy B. Harrington

    2009-01-01

    We evaluated effects of belowground competition on morphology of naturally established coast Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) saplings in 60- to 80-year-old thinned Douglas-fir stands in southwestern Washington. We separately quantified belowground competition from overstory and understory sources...

  1. Early genetic evaluation of open-pollinated Douglas-fir families

    Science.gov (United States)

    Kurt H. Riitters; David A. Perry

    1987-01-01

    In a test of early genetic evaluation of the growth potential of 14 families of open-pollinated Douglas-fir (Pseudotsuga menziesii) [Mirb.] Franco), measures of growth and phenology of seedligns grown in a coldframe were correlated with height of saplings in evaluation plantations at 9, 12, and 15 years. fifteen-year height was most strongly...

  2. Family differences in equations for predicting biomass and leaf area in Douglas-fir (Pseudotsuga menziesii var. menziesii).

    Science.gov (United States)

    J.B. St. Clair

    1993-01-01

    Logarithmic regression equations were developed to predict component biomass and leaf area for an 18-yr-old genetic test of Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco var. menziesii) based on stem diameter or cross-sectional sapwood area. Equations did not differ among open-pollinated families in slope, but intercepts...

  3. Relationships among chilling hours, photoperiod, calendar date, cold hardiness, seed source, and storage of Douglas-fir seedlings

    Science.gov (United States)

    Diane L. Haase; Nabil Khadduri; Euan Mason; Kas Dumroese

    2016-01-01

    Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) seedlings from three nurseries in the Pacific Northwest United States were lifted on five dates from mid-October through mid-December 2006. Each nursery provided seedlings from a low- and a high-elevation seed lot. Photoperiod and accumulated chilling hours (calculated using two methods) were evaluated...

  4. Riparian buffer and density management influences on microclimate of young headwater forests of Western Oregon.

    Science.gov (United States)

    Paul D. Anderson; David J. Larson; Samuel S. Chan

    2007-01-01

    Thinning of 30- to 70-year-old Douglas-fir (Psuedotsuga menziesii [Mirb.] Franco) stands is a common silvicultural activity on federal forest lands of the Pacific Northwest, United States. Empirical relationships among riparian functions, silvicultural treatments, and different riparian buffer widths are not well documented for small headwater...

  5. Stand characteristics of 65-year-old planted and naturally regenerated stands near Sequim, Washington.

    Science.gov (United States)

    Richard E. Miller; Harry W. Anderson

    1995-01-01

    Tree numbers, height, and volume were determined in six 63- to 66-year-old plantations of coast Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) in northwest Washington. These stands resulted from the first extensive plantings of this species in the Pacific Northwest. Data from 0.25-acre plots in these...

  6. Ground-based forest harvesting effects on soil physical properties and Douglas-fir growth.

    Science.gov (United States)

    Adrian Ares; Thomas A. Terry; Richard E. Miller; Harry W. Anderson; Barry L. Flaming

    2005-01-01

    Soil properties and forest productivity can be affected by heavy equipment used for harvest and site preparation but these impacts vary greatly with site conditions and operational practices. We assessed the effects of ground-based logging on soil physical properties and subsequent Douglas-fir [Pseudotsuga menziesii (Mirb) Franco] growth on a highly...

  7. Detecting response of Douglas-fir plantations to urea fertilizer at three locations in the Oregon Coast Range.

    Science.gov (United States)

    Richard E. Miller; Jim Smith; Harry. Anderson

    2001-01-01

    Fertilizer trials in coast Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) in the Oregon Coast Range usually indicate small and statistically nonsignificant response to nitrogen (N) fertilizers. Inherently weak experimental designs of past trials could make them too insensitive to detect growth differences...

  8. Bedrock type significantly affects individual tree mortality for various conifers in the inland Northwest, U.S.A

    Science.gov (United States)

    James A. Moore; David A Hamilton; Yu Xiao; John Byrne

    2004-01-01

    Individual tree mortality models for western white pine (Pinus monticola Dougl. ex D. Don), Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), grand fir (Abies grandis (Dougl. ex D. Don) Lindl.), western redcedar (Thuja plicata Donn ex. D. Don), western hemlock (Tsuga heterophylla (Raf.) Sarg.), and western larch (Larix occidentalis Nutt.) were developed using data...

  9. New host-plant records for the defoliator Ormiscodes amphimone (Fabricius) (Lepidoptera: Saturniidae).

    Science.gov (United States)

    Paritsis, Juan; Elgueta, Mario; Quintero, Carolina; Veblen, Thomas T

    2010-01-01

    Ormiscodes amphimone (Fabricius) is a phytophagous moth species known to severely defoliate woody species in Chile and Argentina. Here we document new records of O. amphimonehost associations emphasizing the role of Nothofagus pumilio as its primary host in our study area. This new record for Argentina is highly significant given the economic importance of N. pumilio as a timber resource and the potential of O. amphimone to generate extensive outbreaks.

  10. New host-plant records for the defoliator Ormiscodes amphimone (Fabricius) (Lepidoptera: Saturniidae)

    OpenAIRE

    Paritsis, Juan; Elgueta, Mario; Quintero, Carolina; Veblen, Thomas T

    2010-01-01

    Ormiscodes amphimone (Fabricius) is a phytophagous moth species known to severely defoliate woody species in Chile and Argentina. Here we document new records of O. amphimonehost associations emphasizing the role of Nothofagus pumilio as its primary host in our study area. This new record for Argentina is highly significant given the economic importance of N. pumilio as a timber resource and the potential of O. amphimone to generate extensive outbreaks.

  11. Thinning shock and response to fertilizer less than expected in young Douglas-fir stand at Wind River Experimental Forest.

    Science.gov (United States)

    Dean S. DeBell; Constance A. Harrington; John. Shumway

    2002-01-01

    Three thinning treatments (thinned to 3.7 by 3.7 m, thinned to 4.3 by 4.3 m, and an unthinned control treatment with nominal spacing averaging 2.6 by 2.6 m) were installed in a 10-year-old Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) plantation growing on a low-quality site at the Wind River Experimental Forest in southwest Washington. Two...

  12. Effects of long-term pruning, meristem origin, and branch order on the rooting of Douglas-fir stem cuttings.

    Science.gov (United States)

    D.L. Copes

    1992-01-01

    The rooting percentages of 14 Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) clones were examined annually from 1974 to 1988. The trees were 10 and 13 years old in 1974 and were pruned to 2.0 m in 1978 and 1979 and then recut annually to 0.5, 1.0, or 1.5 m, starting in 1983. The pruned trees showed no evidence of decreased rooting percentage...

  13. Modulation of Fire Regimes by Vegetation and Site Type in Southwestern Patagonia Since 13 ka

    Directory of Open Access Journals (Sweden)

    Patricio I. Moreno

    2018-04-01

    Full Text Available The degree to which vegetation and site type have influenced fire regimes through the Holocene has not been investigated in detail in the temperate ecosystems of southern Patagonia. Here we present a first attempt using a paired-basin approach to study the evolution of fire regimes in sectors dominated by humid Nothofagus forests and the xeric Patagonian steppe in the Magallanes region of Chilean Patagonia (51°S. We analyzed sediment cores from two small lakes and a bog located within the same climate zone on opposite sides of the forest-steppe ecotone, ~28 km apart. The position of this biological boundary east of the Andes is controlled by the strength and position of the southern westerly winds, which constitute the sole source of precipitation throughout western Patagonia. Our results indicate that fires have occurred in the study region repeated times over the last ~13,000 years at bi- and tridecadal timescales. Sectors currently dominated by Patagonian steppe feature high frequency and low magnitude of local fires, and vice versa in humid forests. Climate-driven expansion of Nothofagus scrubland/woodland into steppe environments over the last ~4,200 years increased the magnitude and lowered the frequency of fire events, culminating with peak Nothofagus abundance, fire magnitude and frequency during the last millennium. We also detect divergences between lake-based vs. bog-based paleofire histories among paired sites located within the Patagonian steppe, ~12 km apart, which we attribute to local burning of the bog at times of lowered water table. This divergence suggests to us that bog-based vegetation and fire histories exacerbate a local, azonal, signal blurring extra-local or regional regimes, thus accounting for some discrepancies in the Quaternary paleovegetation/paleoclimate literature of southern Patagonia.

  14. Use of tree species by White-throated treerunner (Pygarrhichas albogularis King in a secondary native forest of southern Chile

    Directory of Open Access Journals (Sweden)

    Alberto Gantz

    2015-06-01

    Full Text Available ABSTRACT In forest ecosystems, numerous species of insectivorous birds use certain tree species as feeding and nesting substrates. Between 2009 and 2010, the use of different floristic components as feeding substrate by the Pygarrhichas albogularis King, 1831 was evaluated in a southern Chilean secondary native forest. From a total of 13 trees and bush species, six tree species were used by P. albogularis as a feeding substrate. Tree use was limited to intermediate heights (11-20 m and, mainly, to the trunk (40% of observations and secondary branches (26%. Pygarrhichas albogularis showed a disproportionated use of N. dombeyi and an important use of trees with a greater age structure (DBH 81-100 cm. Nothofagus dombeyi presented a significantly greater tree bark crevice depth than E. cordifolia. In turn, covariance between crevice depth and invertebrate supply in tree bark was positive and significant. We consider bark depth and invertebrate supply to be the proximate causes explaining P. albogularis disproportionated use of Nothofagus dombeyi.

  15. Preliminary data on growth and enzymatic abilities of soil fungus Humicolopsis cephalosporioides at different incubation temperatures.

    Science.gov (United States)

    Elíades, Lorena Alejandra; Cabello, Marta N; Pancotto, Verónica; Moretto, Alicia; Rago, María Melisa; Saparrat, Mario C N

    2015-01-01

    Nothofagus pumilio (Poepp & Endl.) Krasser, known as "lenga" is the most important timber wood species in southernmost Patagonia (Argentina). Humicolopsis cephalosporioides Cabral & Marchand is a soil fungus associated with Nothofagus pumilio forests, which has outstanding cellulolytic activity. However, there is no information about the ability of this fungus to use organic substrates other than cellulose, and its ability to produce different enzyme systems, as well as its response to temperature. The aim of this study was to examine the role of H. cephalosporioides in degradation processes in N. pumilio forests in detail by evaluating the in vitro ability of four isolates of this fungus to grow and produce different lytic enzyme systems, and their response to incubation temperature. The ability of the fungi to grow and produce enzyme systems was estimated by inoculating them on agar media with specific substrates, and the cultures were incubated at three temperatures. A differential behavior of each strain in levels of growth and enzyme activity was found according to the medium type and/or incubation temperature. A intra-specific variability was found in H. cephalosporioides. Likewise a possible link between the saprotrophic role of this fungus in N. pumilio forests and the degradation of organic matter under stress conditions, such as those from frosty environments, was also discussed. Copyright © 2013 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

  16. Características del establecimiento e historia de vida de Misodendrum punctulatum (Misodendraceae un muérdago de Sudamérica austral Establishment and life history characteristics of the southern South American mistletoe Misodendrum punctulatum (Misodendraceae

    Directory of Open Access Journals (Sweden)

    Norlan Tercero-Bucardo

    2004-09-01

    Full Text Available Aprovechando la formación de anillos anuales de crecimiento en los hospedadores y que el sistema haustorial de los muérdagos va quedando sincrónicamente embebido en el xilema del hospedador, analizamos características edad dependientes de la historia de vida y del establecimiento de Misodendrum punctulatum cuando infecta a dos especies deciduas de Nothofagus en el noroeste de la Patagonia, Argentina. La determinación de la edad de establecimiento de las infecciones fue realizada examinando el número de anillos anuales de crecimiento del hospedador, en cortes transversales de ramas o troncos principales de Nothofagus, atravesados por el haustorio más profundo. Concomitantemente, se registró el número de eventos anuales de crecimiento (índice de edad aérea y el diámetro basal de los tallos de los muérdagos. Los anillos de crecimiento de los hospedadores precedentes al establecimiento de los muérdagos fueron usados para determinar la edad las ramas o troncos principales al ser infectados. La relación entre la edad haustorial y el índice de edad aérea indican que: (1 el recuento de los eventos de crecimiento de los tallos es un método no destructivo adecuado para estimar la edad de este muérdago mientras que el diámetro basal es un método menos eficiente, (2 al inicio del desarrollo M. punctulatum presenta un período de incubación holotrófico, de varios años, antes de producir estructuras aéreas, (3 la duración del período de incubación es sitio y/u hospedador dependiente siendo más extenso (4 a 6 años en bosques subalpinos de Nothofagus pumilio y más corto (2 años en matorrales de N. antarctica en bajas altitudes ,(4 cuando los muérdagos viven en bosques subalpinos de Nothofagus pumilio en sitios desfavorables crecen más lento y son más longevos que cuando están en matorrales de N. antarctica en bajas altitudes. Misodendrum punctulatum infecta principalmente ramas jóvenes (Taking advantage of host annual ring

  17. Heavy metal and trace elements in riparian vegetation and macrophytes associated with lacustrine systems in Northern Patagonia Andean Range.

    Science.gov (United States)

    Juárez, Andrea; Arribére, María A; Arcagni, Marina; Williams, Natalia; Rizzo, Andrea; Ribeiro Guevara, Sergio

    2016-09-01

    Vegetation associated with lacustrine systems in Northern Patagonia was studied for heavy metal and trace element contents, regarding their elemental contribution to these aquatic ecosystems. The research focused on native species and exotic vascular plant Salix spp. potential for absorbing heavy metals and trace elements. The native species studied were riparian Amomyrtus luma, Austrocedrus chilensis, Chusquea culeou, Desfontainia fulgens, Escallonia rubra, Gaultheria mucronata, Lomatia hirsuta, Luma apiculata, Maytenus boaria, Myrceugenia exsucca, Nothofagus antarctica, Nothofagus dombeyi, Schinus patagonicus, and Weinmannia trichosperma, and macrophytes Hydrocotyle chamaemorus, Isöetes chubutiana, Galium sp., Myriophyllum quitense, Nitella sp. (algae), Potamogeton linguatus, Ranunculus sp., and Schoenoplectus californicus. Fresh leaves were analyzed as well as leaves decomposing within the aquatic bodies, collected from lakes Futalaufquen and Rivadavia (Los Alerces National Park), and lakes Moreno and Nahuel Huapi (Nahuel Huapi National Park). The elements studied were heavy metals Ag, As, Cd, Hg, and U, major elements Ca, K, and Fe, and trace elements Ba, Br, Co, Cr, Cs, Hf, Na, Rb, Se, Sr, and Zn. Geochemical tracers La and Sm were also determined to evaluate contamination of the biological tissues by geological particulate (sediment, soil, dust) and to implement concentration corrections.

  18. Assessing the impact of plantation forestry on plant biodiversity

    Directory of Open Access Journals (Sweden)

    Andreas Ch. Braun

    2017-04-01

    Full Text Available Effects of plantation forestry on biodiversity are controversially discussed in literature. While some authors stress positive effects, others tend to attribute a largely negative influence to plantations. One important factor steering the influence on biodiversity are management practices. A second important factor is the environmental matrix. Chile offers the option to analyse both factors jointly. The coastal range of central Chile has experienced rapid and widespread replacement of native Nothofagus spp. forests in favour of Pinus radiata plantations. Here, native forests remain limited to small patches surrounded by an environmental matrix of plantations. Management is rather intensive and not designed to maintain biodiversity. While in the coastal range of central Chile the transformation from native forests to non-native tree plantations has almost come to an end, spatial extension of P. contorta and P. ponderosa plantations has just recently begun in Chilean Patagonia. While the management is similar to central Chile, plantations rather exist as small patches surrounded by an environmental matrix of native plant formations (e.g. Nothofagus spp. forests and Nothofagus spp. scrublands. In the framework of this work, effects of the two diametric land usages on biodiversity are assessed and compared. Biodiversity is assessed at the α-, β- and γ-scale. At the α-scale, biodiversity impacts are inferred statistically, using one-way ANOVA and Tukey’s PostHoc test. Biodiversity of plants at both sites is significantly reduced in plantations when compared to native forests or scrublands. Plantation forestry lowers α-biodiversity and does not provide additional habitats for specialists. At the β-scale, weak edge effects due to the presence of native forests are observed. In total, plantation forestry tends to promote plant invasions and impairs the survival of endemics. At the γ-scale, plant species communities where predominantly native

  19. A new species of Alsodes (Anura: Alsodidae) from Altos de Cantillana, central Chile.

    Science.gov (United States)

    Charrier, Andrés; Correa, Claudio; Castro, Camila; Méndez, Marco A

    2015-02-05

    Based on morphological and molecular evidence (mitochondrial and nuclear sequences) we describe a new species of spiny-chest frog, Alsodes cantillanensis, from central Chile (around 34°S). The type locality, Quebrada Infiernillo, is located in the Coastal Range at approximately 65 km from Santiago (Metropolitan Region), the capital of Chile. The distribution of the new species is included entirely in that of A. nodosus (32-36°S approximately), which was identified as the sister taxon according to molecular phylogenetic analyses. Moreover, both species are sympatric in the type locality. The new species was found in a Nothofagus macrocarpa relict forest potentially threatened by gold mining activities. We identify other threats for its conservation and some biological data needed for understanding the evolution of this species. This discovery reveals the scarce knowledge about biogeography, evolution and ecology of spiny-chest frogs from central Chile. 

  20. Preliminary results of the first paleontologic investigations in Uruguayan Antarctica

    International Nuclear Information System (INIS)

    Perea, D.; Masquelin, E.; Verde, M.; Querequiz, R.

    1998-01-01

    Preliminary results of the first Uruguayan paleontollogic and biostratigraphical investigations in Antartica are presented. The field work was performed in fildes Peninsula, King George Island, near Uruguayan station Base Cientifica Antarctica Artigas.Some fossiliferous outcrops were geologic and paleontologically analyzed, among them Fossil Hills, situated in the center part of the peninsula, in front of Ardley Island, between the chinese and chilean stations.This hill is composed of fossil bearing piroclastic and epiclastic rocks, assigned to the fossil Hill Fm. Vegetal remains(petrified wood and leaf impronts) were observed and collected in this unit and it is remarkable the presence of Nothofagus sp. and invertebrate trace fossils, Cochlichmus isp and Helminthopsis isp.The depositional environment deduced from the fossil association in lacustrine, under a warm and humid climate.In the same deposits, other investigators have collected aquatic and ratite bird trace fossils. Paleontologic evidence is not contradictory with the Eocene age previously proposed for the studied deposits. (author)

  1. Stratigraphy and paleontology of fossil hill Peninsula Fildes, Rey Jorge island, Antarctica: a new approach

    International Nuclear Information System (INIS)

    Perea, D.; Masquelin, H.; Verde, M.; Guerequiz, R.

    1998-01-01

    Results of the first Uruguayan paleontologic and biostratigraphical investigations in Antarctica are presented.The field work was performed in Fildes Peninsula, King George Island, near the Uruguayan station Base Cientifica Antartida Artigas. Some fossiliferous outcrops were geologic and pale ontologically analyzed, among them the Fossil Hill, placed in the middle part of the peninsula, in front of Ardley Island between the Chinese and Chilean stations. This hill is composed of fossil bearing piroclastic and epiclastic rocks, assigned to the Fossil Hill Fm.Vegetal remains (petrified wood and leaf impronts)were observed and collected in this unit and it is remarkable the presence of Nothofagus sp. and invertebrate trace fossils Cochlichnus isp and Helminthopsis isp.

  2. Decoupling of unpolluted temperate forests from rock nutrient sources revealed by natural 87Sr/86Sr and 84Sr tracer addition

    Science.gov (United States)

    Kennedy, Martin J.; Hedin, Lars O.; Derry, Louis A.

    2002-01-01

    An experimental tracer addition of 84Sr to an unpolluted temperate forest site in southern Chile, as well as the natural variation of 87Sr/86Sr within plants and soils, indicates that mechanisms in shallow soil organic horizons are of key importance for retaining and recycling atmospheric cation inputs at scales of decades or less. The dominant tree species Nothofagus nitida feeds nearly exclusively (>90%) on cations of atmospheric origin, despite strong variations in tree size and location in the forest landscape. Our results illustrate that (i) unpolluted temperate forests can become nutritionally decoupled from deeper weathering processes, virtually functioning as atmospherically fed ecosystems, and (ii) base cation turnover times are considerably more rapid than previously recognized in the plant available pool of soil. These results challenge the prevalent paradigm that plants largely feed on rock-derived cations and have important implications for understanding sensitivity of forests to air pollution. PMID:12119394

  3. A new species of Rhytidognathus (Carabidae, Migadopini) from Argentina.

    Science.gov (United States)

    Roig-Juñent, Sergio; Rouaux, Julia

    2012-01-01

    The Migadopini are a small tribe of Carabidae with 47 species that occur in South America, Australia, and New Zealand, in the sub-Antarctic areas. In South America, most of the genera inhabit areas related to sub-Antartic Nothofagus forest except two monogeneric genera, the Ecuadorian genus Aquilex Moret and the Pampean genus Rhytidognathus Chaudoir. These two genera are geographically isolated from the remaining five South American genera. New material of Rhytidognathus from the northeast of Buenos Aires province and from Entre Ríos province permits establishing that the previous records of Rhytidognathus ovalis (Dejean) for Argentina were erroneous and that it belongs to a new species. Based on external morphological characters and from male and female genitalia we describe Rhytidognathus platensis as a new species. In this contribution we provide illustrations, keys, habitat characteristics and some biogeographic considerations on the distribution of Rhytidognathus.

  4. A new species of Rhytidognathus (Carabidae, Migadopini from Argentina

    Directory of Open Access Journals (Sweden)

    Sergio Roig-Junent

    2012-11-01

    Full Text Available The Migadopini are a small tribe of Carabidae with 47 species that occur in South America, Australia, and New Zealand, in the sub-Antarctic areas. In South America, most of the genera inhabit areas related to sub-Antartic Nothofagus forest except two monogeneric genera, the Ecuadorian genus Aquilex Moret and the Pampean genus Rhytidognathus Chaudoir. These two genera are geographically isolated from the remaining five South American genera. New material of Rhytidognathus from the northeast of Buenos Aires province and from Entre Ríos province permits establishing that the previous records of Rhytidognathus ovalis (Dejean for Argentina were erroneous and that it belongs to a new species. Based on external morphological characters and from male and female genitalia we describe Rhytidognathus platensis as a new species. In this contribution we provide illustrations, keys, habitat characteristics and some biogeographic considerations on the distribution of Rhytidognathus.

  5. EFECTO DE LA VEGETACIÓN EN LA INTERCEPCIÓN DE LA PRECIPITACIÓN EN LA PRECORDILLERA DE LA REGIÓN DEL MAULE, CHILE

    Directory of Open Access Journals (Sweden)

    O. S. Vallejos-Barra

    2010-01-01

    Full Text Available En este estudio se comparó el comportamiento de un bosque secundario de Roble-Hualo, donde las especies predominantes son Nothofagus obliqua y Nothofagus glauca y una plantación de Pinus radiata D. Don de 12 años de edad, en el proceso precipitación - intercepción. El estudio se desarrolló en la Estación Experimental El Picazo, comuna de San Clemente, Región del Maule, Chile, entre el mes de julio de 2007 a julio de 2008, en dos microcuencas vecinas de dimensiones reducidas con condiciones similares de suelo, exposición y pendiente pero que diferían en la cobertura vegetal. Se caracterizó la vegetación de cada microcuenca y se establecieron indicadores de densidad de parcela. Los indicadores de la cobertura nativa superaron ampliamente a los de las coberturas exóticas. Para registrar la precipitación se instalaron dos pluviógrafos del tipo Hobo en cada microcuenca. Equidistante de ellas se ubicó otro pluviógrafo sin cobertura vegetal. Se registraron 21 tormentas caracterizando temporal y espacialmente el comportamiento de la precipitación abierta y bajo dosel. Los resultados indican que pese a tener diferencias numéricas las coberturas vegetales, éstas no se transforman en diferencias estadísticamente significativas. Además se observó que la intercepción depende en mayor medida de la arquitectura de copa, distribución espacial de los árboles y tipo de hojas, que de la cantidad de árboles por parcela.

  6. Holocene Dynamics of Temperate Rainforests in West-Central Patagonia

    Directory of Open Access Journals (Sweden)

    Virginia Iglesias

    2018-01-01

    Full Text Available Analyses of long-term ecosystem dynamics offer insights into the conditions that have led to stability vs. rapid change in the past and the importance of disturbance in regulating community composition. In this study, we (1 used lithology, pollen, and charcoal data from Mallín Casanova (47°S to reconstruct the wetland, vegetation, and fire history of west-central Patagonia; and (2 compared the records with independent paleoenvironmental and archeological information to assess the effects of past climate and human activity on ecosystem dynamics. Pollen data indicate that Nothofagus-Pilgerodendron forests were established by 9,000 cal yr BP. Although the biodiversity of the understory increased between 8,480 and 5,630 cal yr BP, forests remained relatively unchanged from 9,000 to 2,000 cal yr BP. The charcoal record registers high fire-episode frequency in the early Holocene followed by low biomass burning between 6,500 and 2,000 cal yr BP. Covarying trends in charcoal, bog development, and Neoglacial advances suggest that climate was the primary driver of these changes. After 2,000 cal yr BP, the proxy data indicate (a increased fire-episode frequency; (b centennial-scale shifts in bog and forest composition; (c the emergence of vegetation-fire linkages not recorded in previous times; and (d paludification in the last 500 years possibly associated with forest loss. Our results therefore suggest that Nothofagus-Pilgerodendron dominance was maintained through much of the Holocene despite long-term changes in climate and fire. Unparalleled fluctuations in local ecosystems during the last two millennia were governed by disturbance-vegetation-hydrology feedbacks likely triggered by greater climate variability and deforestation.

  7. Comparison between mycocenosis living in forest of Cestnut reforested with Douglas Fir; Confronto tra micocenosi presenti nei boschi di latifoglie e rimboschimenti di Douglasia

    Energy Technology Data Exchange (ETDEWEB)

    Andreotti, A.; Serra, F. [ENEA, Centro Ricerche Brasimone, Bologna (Italy). Dipt. Ambiente; Dalla Valle, E.; Govi, G. [Bologna, Univ. (Italy). Dipt. di Protezione e Valorizzazione Agroalimentare. Centro di Micologia

    1997-05-01

    In this technical report the results of a first mycological research carried out from 1989 to 1990 in Brasimone in the high Bolognan Appennines (Northern Italy) are shown. The study was taken up by making a comparison between the fungus community living in forest plots with different vegetation; in particular, the mycocenosis of plots reforested with Douglas Fir (Pseudotsuga (Mirb.) Franco) with those of Beech (Fagus sylvatica L.) and Cestnut (Castanea sativa Mill.) woods were compared. The results show that the specific richness clearly decreases form mixed broad-leaved forest (90 species) to the mono specific plantation of P. menziesii (41 species). Particularly in the artificial plantation with exotic trees, there are few symbiont species while the saprophytic wood and litter fungi abound in relationship with the large bulk of undecomposed vegetable material present in these habitats.

  8. Climate Responses in Growth and Wood Anatomy of Imoprtant Forest Tree Species in Denmark

    DEFF Research Database (Denmark)

    Huang, Weiwei

    and high temperatures on the development of Danish tree species are scarcely investigated. Through a dendroecological approach this dissertation assessed the growth responses related to increment, xylem anatomy and wood property of eight different important tree species, namely Picea abies (L.) Karst......., Picea sitchensis (Bong.) Carr., Abies alba Mill., Abies grandis (Dougl.) Lindl., Pseudotsuga mensiesii (Mirb.) Franco, Larix kaempferi (Lamb.) Carr., Quercus robur L. and Fagus sylvatica L., to long-term drought and high temperatures, aiming at identifying a species portfolio matching future climate...... intolerant species, mainly due to their low drought tolerance (both species) and susceptibility to high autumn temperature (only P. abies). Overall, this dissertation improves the understanding of how drought and high temperatures have impacted and will influence the growth of tree species in Danish forest...

  9. Biogeochemical prospecting for uranium with conifers: results from the Midnite mine area, Washington

    International Nuclear Information System (INIS)

    Nash, J.T.; Ward, F.N.

    1977-01-01

    The ash of needles, cones, and duff from Ponderosa pine (Pinus ponderosa Laws) growing near uranium deposits of the Midnite mine, Stevens County, Wash., contain as much as 200 ppM uranium. Needle samples containing more than 10 ppM uranium define zones that correlate well with known uranium deposits or dumps. Dispersion is as much as 300 m but generally is less. Background is about 1 ppM. Tree roots are judged to be sampling ore, low-grade uranium halo, or ground water to a depth of about 15 m. Uptake of uranium by Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) needles appears to be about the same as by Ponderosa pine needles. Cones and duff are generally enriched in uranium relative to needles. Needles, cones, and duff are recommended as easily collected, uncomplicated sample media for geochemical surveys. Samples can be analyzed by standard methods and total cost per sample kept to about $6

  10. Riparian leaf litter processing by benthic macroinvertebrates in a woodland stream of central Chile Procesamiento de detritus ripariano por macroinvertebrados bentónicos en un estero boscoso de Chile central

    Directory of Open Access Journals (Sweden)

    CLAUDIO VALDOVINOS

    2001-06-01

    Full Text Available Leaf litter input from riparian landscapes has been identified as both a major energy flow to stream ecosystems and as a food source for stream macroinvertebrates. In riparian landscapes of woodland streams of central Chile, the native deciduous hardwoods are being artificially replaced by exotic coniferous trees at a large spatial scale. It is suggested that this process has a significant impact on the stream communities of central Chile. Today, exotic plantations occur throughout central Chile, with Pinus radiata (D. Don (Monterrey pine accounting for about 80 % of the more than 1,800,000 ha of exotic forests. The objective of this paper was to analyze the effect of the litter beds of a dominant native species (Nothofagus pumilio and an exotic species (P. radiata on the detritus processing carried out by benthic macroinvertebrates, in an experimental catchment of central Chile (Rucúe Creek; 36° 26'00" S, 71° 35'40" W. Results revealed that processing rates of native leaf packs are higher than rates of coniferous leaf packs, suggesting that the replacement of the native hardwoods by exotic coniferous riparian flora has an important impact on the stream energy flow in central Chile. The decay rate coefficients (k were 0.0072 for N. pumilio, and 0.0027 for P. radiata. The greater abundance and biomass of shredders per gram of leaf pack of native Nothofagus would explain the differences in leaf processing rates, especially through the activity of two Plecoptera Gripopterygidae, Limnoperla jaffueli and Antarctoperla michaelseniLa entrada de detritus foliar procedente de áreas riparianas ha sido reconocido como un componente importante en la energética de ecosistemas fluviales y como fuente de alimento de macroinvertebrados acuáticos. En áreas riparianas de esteros boscosos de Chile central los componentes nativos caducifolios están siendo artificialmente reemplazados a gran escala por coníferas exóticas, sugiriendo que este proceso tiene

  11. Miocene Antarctic Terrestrial Realm

    Science.gov (United States)

    Ashworth, A. C.; Lewis, A.; Marchant, D. R.

    2009-12-01

    The discovery of several locations in the Transantarctic Mountains that contain macrofossils and pollen is transforming our understanding of late Cenozoic Antarctica. The most southerly location is on the Beardmore Glacier (85.1°S) about 500 km from the South Pole. The environment was an active glacial margin in which plants, insects and freshwater mollusks inhabited the sand and gravel bars and small lakes on an outwash plain. In addition to leaves and wood of dwarf Nothofagus (Southern Beech) shrubs, achenes of Ranunculus (Buttercup), in situ cushion growth forms of mosses and a vascular plant, the assemblages contains various exoskeletal parts of carabid and curculionid beetles and a cyclorrhaphan fly, the shells of freshwater bivalve and gastropod species and a fish tooth. Initially the deposits were assigned a Pliocene age (3.5 Ma) but a mid- to early Miocene age is more probable (c. 14 - 25 Ma) based on correlation of fossil pollen from the deposits with 39Ar/40Ar dated pollen assemblages from the McMurdo Dry Valleys locations. The oldest location within the Dry Valleys also involved an active ice margin but was part of a valley system that was completely deglaciated for intervals long enough for thick paleosols to develop. The Friis Hills fossil deposits of the Taylor Valley region (77.8°S) are at least 19.76 Ma based on the 39Ar/40Ar age of a volcanic ash bed. The valley floor during the non-glacial phases had poorly-drained soils and the extensive development of mossy mires. Wood and leaves of Nothofagus are abundant in lacustrine deposits. The silts of shallow fluvial channels contain abundant megaspores and spiky leaves of the aquatic lycopod Isoetes (Quillwort). Fossils of beetles are also present in these deposits. During the glacial phases, proglacial lakes were surrounded by dwarfed, deciduous Nothofagus shrubs. The youngest fossils recovered from the Dry Valleys are from the Olympus Range (77.5°S) with an age of 14.07 Ma. The environment was an

  12. EL CAMBIO CLIMÁTICO DURANTE LOS ÚLTIMOS 15.000 AÑOS EN PATAGONIA NORTE. RECONSTRUCCIONES DE LA VEGETACIÓN EN BASE A POLEN Y CARBÓN VEGETAL SEDIMENTARIO.

    Directory of Open Access Journals (Sweden)

    María Martha Bianchi

    2007-12-01

    Full Text Available Los cambios de la vegetación, en cuencas lacustres en la región del bosque Andino Patagónico y el ecotono bosque-estepa, determinados a partir del análisis de polen y carbón vegetal sedimentario permitieron inferir cambios climáticos en el área de Patagonia norte desde la Tanscición Glacial-Post-glacial, 15.000 años A.P. Se presentan aquí algunos de los resultados más relevantes obtenidos con metodologías de alto nivel, en el área del Parque Nacional Nahuel Huapi durante 17 años de estudio, en los que se extrajeron y analizaron testigos sedimentarios en lagos y mallines: Lago Mascardi, Lago El Trébol, Lago Escondido y Mallín Aguado. Los análisis de polen y de carbón vegetal sedimentario de secuencias bien datadas con el método de 14C indican que una estepa arbustiva fue remplazada por un bosque abierto a comienzos de la Transición Glacial-post-glacial bajo un clima más seco y más frió que el actual. Hacia fines de la Transición se produjo la diversificación del bosque. Durante la Inversión Climática Huelmo Mascardi, el bosque se hizo más abierto hacia el oeste y se produjeron incendios de alta severidad hacia el este, sugiriendo una disminución en la temperatura hacia el oeste y en las condiciones de humedad a lo largo del gradiente Oeste- Este. El bosque de Nothofagus adquirió su mayor extensión y los incendios continuaron durante el Holoceno Inferior. Durante el Holoceno Medio se produjo el reemplazo del bosque de Nothofagus por el bosque mixto de Nothofagus y Austrocedrus chilensis, gracias a un incremento en las precipitaciones, principalmente de verano. La expansión del bosque hacia el este ocurrió gradualmente y fue acompañado por un cambio en el régimen de incendios, los que se hicieron más frecuentes pero menos severos. Durante el Holoceno Superior el bosque se hizo más denso y continuó expandiéndose bajo condiciones de mayor variabilidad climática. Actualmente las investigaciones contin

  13. The early to mid-Miocene environment of Antarctica

    Science.gov (United States)

    Ashworth, A. C.; Lewis, A.

    2012-12-01

    Paleoecological studies in the Transantarctic Mountains of the McMurdo region provide evidence that the climate was both warmer and wetter in the early to mid-Miocene than it was during the late Miocene. The climate change was accompanied by a shift from wet- to cold-based glaciation in the TAM and the probable growth of the polar ice sheet. Terrestrial and freshwater aquatic fossil assemblages from the Friis Hills (77°S) and the Olympus Range (77°S), with endpoint 40Ar/39Ar ages on tephras of 19.76 Ma and 14.07 Ma, respectively, indicate climatic cooling during the interval. At c.14 Ma, the temperature dropped below the threshold required to support the plants and insects of a tundra biome, and they became extinct. This interpretation is supported by pollen studies from Ross Sea cores. The extinction of the tundra biota on the continent appears to have been time-transgressive, occurring at 12.8 Ma on the Antarctic Peninsula. Evidence of climatic cooling from early to mid-Miocene is based on a decrease in biodiversity. During interglacial phases of the early Miocene, the poorly drained valley of the Friis Hills supported a sexually-reproducing moss community dominated by Campylium cf. polygamum, which today grows on the margins of lakes and in soil between boulders. Wood and leaves of Nothofagus (Southern Beech), and the seeds of at least five other angiosperm species are preserved as fossils. In addition, there are abundant megaspores and spiny, curved leaves of the aquatic lycopod Isoetes (Quillwort), as well as chitinous remains of curculionid beetles and Chironomidae (midges). During glacial phases, the only fossils found are Nothofagus leaves of a species which appears to be different than that associated with the interglacial phases. Pollen supports the interpretation that there was more than one species of Nothofagus in the vegetation. The types and numbers of species indicate that the vegetation was a shrub tundra. The closest modern analog for the fossil

  14. Levaduras fermentadoras aisladas de Cyttaria hariotii (Fungi en bosques Andino-Patagónicos (Argentina Fermenting yeasts isolated from Cyttaria hariotii (Fungi in the Andean Patagonic Forest

    Directory of Open Access Journals (Sweden)

    José Ulloa

    2009-12-01

    Full Text Available Las levaduras han estado asociadas al hombre desde épocas muy tempranas. Entre estas se destacan las fermentadoras debido a su importancia en la industria de los alimentos. Las implicancias biotecnológicas de estas levaduras han sido extensamente estudiadas, sin embargo la distribución en la naturaleza y la ecología de estas no se encuentra igualmente documentada. El presente estudio se realizó en el Parque Nacional Nahuel Huapi (Noroeste Patagónico, Argentina sobre Cyttaria hariotii, hongo ascomicético parásito de árboles del género Nothofagus. Mediante el uso de un medio selectivo con etanol 8 % se obtuvieron 72 aislamientos. Los mismos fueron ordenados en cinco grupos en base a pruebas morfológicas y fisiológicas, tres de los cuales fueron asignados a los géneros Saccharomyces, Pichia y Kloeckera. El grupo Saccharomyces presentó el mayor número de aislamientos y se subdividió en tres subgrupos, dos de ellos presentan alta afinidad con S. bayanus y/ó S. uvarum. La totalidad de los aislamientos fueron psicrotolerantes y la temperatura máxima de crecimiento osciló entre 35 y 37 _C. El presente trabajo contribuye al conocimiento de la biodiversidad de levaduras de la Patagonia y representa el primer aislamiento masivo de levaduras sacaromicéticas en ambientes naturales de la región.Yeasts have been associated with mankind from early ages. Among these, fermentative yeasts played the most relevant role, due to its importance in the food industry. The biotechnological implications of these yeasts have been extensively studied. However there is a lack of information about its distribution in nature and ecology. In this study samples of Cyttaria hariotii, ascomycete fungus parasite of trees of the genus Nothofagus, were collected in Nahuel Huapi National Park (Northwestern Patagonia, Argentina. 72 isolates were obtained using a selective culture medium with 8% ethanol. Identification of the isolates was based on morphological and

  15. Selection of Entomopathogenic Nematodes against Dalaca pallens (Lepidoptera: Hepialidae Selección de Nematodos Entomopatógenos para el Control de Dalaca pallens (Lepidóptera: Hepialidae

    Directory of Open Access Journals (Sweden)

    Alexis Maldonado

    2012-06-01

    Full Text Available Dalaca pallens (Blanchard is a pest with great impact on grassland production in Chile. The objective of this research was to evaluate the use of entomopathogenic nematodes (EPN against D. pallens larvae. Twenty EPN isolates, collected along Chile, were used for nematode selection. The experimental unit consisted of five 50-mL plastic vials filled with Nothofagus dombeyi sawdust and inoculated with 40 dauers per vial. The experimental design was a completely randomized with four replicates per treatment. The results showed that isolate QU N3 (Steinernema australe and QU N13 (Steinernema unicornum produced the highest mortality, with 100 and 95% respectively and no differences (P Dalaca pallens (Blanchard es considerada una de las plagas de mayor incidencia para la producción de las praderas en Chile. El objetivo de esta investigación fue la selección de aislamientos nativos de nematodos entomopatógenos (EPN para el control de larvas de D. pallens. Se utilizaron 20 aislamientos nativos de EPN, para cada uno se inocularon 40 dauers por frascos cónicos con aserrin de Nothofagus dombeyi, y se agregó una larva de D. pallens de cuarto instar. Luego, se incubaron a 15 °C y oscuridad y se registró la mortalidad diaria. Se realizaron cuatro repeticiones por tratamiento y la unidad experimental fue de cinco frascos. Los resultados mostraron que el aislamiento QU N3 de Steinernema australe alcanzó el 100% de mortalidad a los 15 días de incubación, sin mostrar diferencias (P < 0,001 con el tratamiento QU N13 (Steinernema unicornum, el cual alcanzó un 95%. Para el cálculo de la concentración letal (CL50 y CL90 se usaron los dos aislamientos mencionados, y se evaluaron concentraciones de 0, 10, 20, 30, 40 y 50 dauers por frasco que contenian una larva de D. pallens de cuarto instar. Para el aislamiento QU N3 la CL50 y CL90 fue de 14 y 39 dauers mL-1, a los 13 d de incubación, mientras que para QU N13 estos valores fueron de 14 y 48 dauers mL-1

  16. Philodryas chamissonis (Reptilia: Squamata: Colubridae preys on the arboreal marsupial Dromiciops gliroides (Mammalia: Microbiotheria: Microbiotheriidae Philodryas chamissonis (Reptilia: Squamata: Dipsadidae predando o marsupial arborícola Dromiciops gliroides (Mammalia: Microbiotheria: Microbiotheriidae

    Directory of Open Access Journals (Sweden)

    S. Muñoz-Leal

    2013-02-01

    Full Text Available Philodryas chamissonis, the Chilean long-tailed snake, is a diurnal predator mainly of Liolaemus lizards, but also of amphibians, birds, rodents and juvenile rabbits. Dromiciops gliroides (Colocolo opossum is an arboreal marsupial endemic of temperate rainforest of southern South America. Little information is available about this marsupial's biology and ecology. Here we report the predation of one Colocolo opossum by an adult female P. chamissonis in a mixed Nothofagus forest, composed mainly by N. dombeyi, N. glauca and N. alpina trees, in the "Huemules de Niblinto" National Reserve, Nevados de Chillán, Chile. Since these two species have different activity and habitat use patterns, we discuss how this encounter may have occurred. Although it could just have been an opportunistic event, this finding provides insights into the different components of food chains in forest ecosystems of Chile.Philodryas chamissonis, cobra de cauda comprida ("Culebra de cola larga", é uma cobra diurna, predadora principalmente de lagartos do gênero Liolaemus, mas também de anfíbios, aves, roedores e coelhos jovens. Dromiciops gliroides (colocolo é um marsupial arborícola endêmico das florestas temperadas do sul da América do Sul. Há pouca informação disponível sobre a biologia e a ecologia deste marsulpial. É reportada, neste estudo, a predação de um colocolo por uma fêmea adulta de P. chamissonis, em uma floresta mista de Nothofagus, composta principalmente por árvores N. dombeyi, N. glauca e N. alpina, na Reserva Nacional de Huemules de Niblinto, Nevados de Chillán, Chile. Uma vez que estas duas espécies possuem diferentes padrões de atividade e de uso de habitat, discute-se como este evento poder ter ocorrido. Embora este possa ter sido apenas um evento oportunístico, o achado fornece novas informações sobre os diferentes componentes da cadeia alimentar nos ecossistemas florestais do Chile.

  17. Can native plant species be preserved in an anthropogenic forest landscape dominated by aliens? A case study from Mediterranean Chile

    Directory of Open Access Journals (Sweden)

    Steffi Heinrichs

    2016-06-01

    Full Text Available Plantations with fast growing exotic tree species can negatively affect native plant species diversity and promote the spread of alien species. Mediterranean Chile experienced major landscape changes with a vast expansion of industrial plantations of Pinus radiata in the past. However, with increasing knowledge of biodiversity effects on ecosystem services Chilean forest owners now aim to integrate the conservation of native biodiversity into forest management, but data on native species diversity and establishment within a plantation landscape is scarce. Here we investigated plant species diversity and composition in four forest management options applied within a landscape dominated by P. radiata plantations in comparison to an unmanaged reference: (i a clear cut, (ii a strip cut, (iii a native canopy of Nothofagus glauca and (iv a young P. radiata plantation. We wanted to assess if native plant species can be maintained either by natural regeneration or by planting of native tree species (Nothofagus glauca, N. obliqua, Quillaja saponaria within this landscape. Results show a high diversity of native and forest plant species within the different management options indicating a high potential for native biodiversity restoration within an anthropogenic landscape. In particular, herbaceous species can benefit from management. They are rare in unmanaged natural forests that are characterized by low light conditions and a thick litter layer. Management, however, also promoted a diversity of alien species. The rapid spread of alien grass species after management can deter an initial establishment of native tree species or the survival and growth after planting mainly under dry but less under sufficient moisture conditions. The most unsuccessful option for promoting native plant species was clear cutting in a dry area where alien grasses were abundant. For drought-tolerant tree species such as Quillaja saponaria, though

  18. Plesiosaur-bearing rocks from the Late Cretaceous Tahora Fm, Mangahouanga, New Zealand - a palaeoenvironmental study

    Science.gov (United States)

    Vajda, Vivi; Raine, J. Ian

    2010-05-01

    Mangahouanga Stream, Hawkes Bay, New Zealand is world-famous for its high southern latitude vertebrate fossils including plesiosaurs, mosasaurs and more rarely, dinosaurs. The fossils are preserved in the conglomeratic facies of the Maungataniwha Sandstone Member of the Tahora Formation. A palynological investigation of sediments from the boulders hosting vertebrate fossils reveals well-preserved palynological assemblages dominated by pollen and spores from land plants but also including marine dinoflagellate cysts in one sample. The palynofacies is strongly dominated by wood fragments including charcoal, and the sample taken from a boulder hosting plesiosaur vertebrae is entirely terrestrially derived, suggesting a fresh-water habitat for at least some of these plesiosaurs. The key-pollen taxa Nothofagidites senectus and Tricolpites lilliei, together with the dinocyst Isabelidinium pellucidum and the megaspore Grapnelispora evansii, strongly indicate an early Maastrichtian age for the host rock. The terrestrial palynoflora reflects a mixed vegetation dominated by podocarp conifers and angiosperms with a significant tree-fern subcanopy component. The presence of taxa with modern temperate distributions such as Nothofagus (southern beech), Proteaceae and Cyatheaceae (tree-ferns), indicates a mild-temperate climate and lack of severe winter freezing during the latest Cretaceous, providing an ecosystem which most probably made it possible for polar dinosaurs to overwinter. The paper is dedicated to Mrs Joan Wiffen who with her great persistence, enthusiasm and courage put Mangahouanga on the world map, becoming a role model for many young scientists.

  19. Paleoenvironmental and paleoclimatic investigations on Isla de los Estados, Argentina

    Science.gov (United States)

    Björck, S.; Fernandez, M.; Hjort, C.; Ljung, K.; Martinez, O.; Möller, P.; Ponce, F.; Rabassa, J.; Roig, F.; Unkel, I.; Wohlfarth, B.

    2007-05-01

    The expedition in November-December 2005 to Isla de los Estados (Staten Island) off the southeastern tip of South America was a cooperative venture between Lund University (LU) and Stockholm University (SU) in Sweden and the CADIC-CONICET Institute in Ushuaia, Argentina. The aim of the expedition was threefold: (1) to extend the Swedish paleoclimatic "ATLANTIS"-project (Greenland, Iceland, Faroe Islands, Azores, Grenada, Tristan da Cunha; PI S Björck) to the southern part of the South American continent, (2) to connect earlier glacial and climate history reconstructions from the Antarctic Peninsula to equivalents north of the Drake Passage in southernmost South America, and (3) to complement paleo-information available from the Tierra del Fuego mainland with information from Isla de los Estados. Focus was on two areas in the northern and north-western part of the island, Bahía Colnett and Bahia Crossley. Detailed geomorphologic and stratigraphic mapping of glacial deposits were combined with sampling sediments for OSL dating. To reconstruct the paleoclimatic development of Isla de los Estados since the last ice retreat, four main peat bog/lake sites were cored and sampled. In addition, living trees of Nothofagus and old logs preserved in the peat were sampled for dendrochronological and dendroclimatological studies. Preliminary results show that the deglaciation of the study area occurred before 16500 cal yr BP. Detailed multi- proxy analyses of the four sequences are under way and first results will be presented.

  20. From leaves to landscape: A multiscale approach to assess fire hazard in wildland-urban interface areas.

    Science.gov (United States)

    Ghermandi, Luciana; Beletzky, Natacha A; de Torres Curth, Mónica I; Oddi, Facundo J

    2016-12-01

    The overlapping zone between urbanization and wildland vegetation, known as the wildland urban interface (WUI), is often at high risk of wildfire. Human activities increase the likelihood of wildfires, which can have disastrous consequences for property and land use, and can pose a serious threat to lives. Fire hazard assessments depend strongly on the spatial scale of analysis. We assessed the fire hazard in a WUI area of a Patagonian city by working at three scales: landscape, community and species. Fire is a complex phenomenon, so we used a large number of variables that correlate a priori with the fire hazard. Consequently, we analyzed environmental variables together with fuel load and leaf flammability variables and integrated all the information in a fire hazard map with four fire hazard categories. The Nothofagus dombeyi forest had the highest fire hazard while grasslands had the lowest. Our work highlights the vulnerability of the wildland-urban interface to fire in this region and our suggested methodology could be applied in other wildland-urban interface areas. Particularly in high hazard areas, our work could help in spatial delimitation policies, urban planning and development of plans for the protection of human lives and assets. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Attraction and antennal response of the common wasp, Vespula vulgaris (L.), to selected synthetic chemicals in New Zealand beech forests.

    Science.gov (United States)

    El-Sayed, Ashraf M; Manning, Lee-Anne; Unelius, C Rikard; Park, Kye Chung; Stringer, Lloyd D; White, Nicola; Bunn, Barry; Twidle, Andrew; Suckling, David M

    2009-09-01

    The common wasp, Vespula vulgaris (L.), and the German wasp, Vespula germanica (F.), are significant problems in New Zealand beech forests (Nothofagus spp.), adversely affecting native birds and invertebrate biodiversity. This work was undertaken to develop synthetic attractants for these species to enable more efficient monitoring and management. Seven known wasp attractants (acetic acid, butyl butyrate, isobutanol, heptyl butyrate, octyl butyrate and 2,4-hexadienyl butyrate) were field tested, and only heptyl butyrate and octyl butyrate attracted significantly higher numbers of wasps than a non-baited trap. Accordingly, a series of straight-chain esters from methyl to decyl butyrate were prepared and field tested for attraction of social wasps. Peak biological activity occurred with hexyl butyrate, heptyl butyrate, octyl butyrate and nonyl butyrate. Polyethylene bags emitting approximately 18.4-22.6 mg day(-1) of heptyl butyrate were more attractive than polyethylene bags emitting approximately 14.7-16.8 mg day(-1) of heptyl butyrate in the field. Electroantennogram (EAG) studies indicated that queens and workers of V. vulgaris had olfactory receptor neurons responding to various aliphatic butyrates. These results are the first to be reported on the EAG response and the attraction of social wasps to synthetic chemicals in New Zealand beech forests and will enable monitoring of social wasp activity in beech forests. Copyright 2009 Society of Chemical Industry.

  2. Assessing the interaction between mountain forests and snow avalanches at Nevados de Chillán, Chile and its implications for ecosystem-based disaster risk reduction

    Science.gov (United States)

    Casteller, Alejandro; Häfelfinger, Thomas; Cortés Donoso, Erika; Podvin, Karen; Kulakowski, Dominik; Bebi, Peter

    2018-04-01

    Gravitational natural hazards such as snow avalanches, rockfalls, shallow landslides and volcanic activity represent a risk to mountain communities around the world. In particular, where documentary records about these processes are rare, decisions on risk management and land-use planning have to be based on a variety of other sources including vegetation, tree-ring data and natural hazard process models. We used a combination of these methods in order to evaluate dynamics of natural hazards with a focus on snow avalanches at Valle Las Trancas, in the Biobío region in Chile. Along this valley, natural hazards threaten not only the local human population, but also the numerous tourists attracted by outdoor recreational activities. Given the regional scarcity of documentary records, tree-ring methods were applied in order to reconstruct the local history of snow avalanches and debris flow events, which are the most important weather-related processes at respective tracks. A recent version of the model Rapid Mass MovementS (RAMMS), which includes influences of forest structure, was used to calculate different avalanche parameters such as runout distances and maximum pressures, taking into consideration the presence or absence of forest along the tracks as well as different modeled return periods. Our results show that local Nothofagus broadleaf forests contribute to a reduction of avalanche runout distances as well as impact pressure on present infrastructure, thus constituting a valuable ecosystem disaster risk reduction measure that can substitute or complement other traditional measures such as snow sheds.

  3. The Gondwanan connection - Southern temperate Amanita lineages and the description of the first sequestrate species from the Americas.

    Science.gov (United States)

    Truong, Camille; Sánchez-Ramírez, Santiago; Kuhar, Francisco; Kaplan, Zachary; Smith, Matthew E

    2017-08-01

    Amanita is a diverse and cosmopolitan genus of ectomycorrhizal fungi. We describe Amanita nouhrae sp. nov., a new hypogeous ('truffle-like') species associated with Nothofagus antarctica in northern Patagonia. This constitutes the first report of a sequestrate Amanita from the Americas. Thick-walled basidiospores ornamented on the interior spore wall ('crassospores') were observed consistently in A. nouhrae and its sister epigeous taxon Amanita morenoi, a rarely collected but apparently common species from northern Patagonia that has sometimes been misidentified as the Australian taxon Amanita umbrinella. Nuclear 18S and 28S ribosomal DNA and mitochondrial 16S and 26S DNA placed these two species in a southern temperate clade within subgenus Amanita, together with other South American and Australian species. Based on a dated genus-level phylogeny, we estimate that the southern temperate clade may have originated near the Eocene/Oligocene boundary (ca. 35 Ma ± 10 Ma). This date suggests a broadly distributed ancestor in the Southern Hemisphere, which probably diversified as a result of continental drift, as well as the initiation of the Antarctic glaciation. By comparison, we show that this clade follows an exceptional biogeographic pattern within a genus otherwise seemingly dominated by Northern Hemisphere dispersal. Copyright © 2017 British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  4. The taphonomy of a remarkable leaf bed assemblage from the Late Oligocene-Early Miocene Gore Lignite Measures, southern New Zealand

    Energy Technology Data Exchange (ETDEWEB)

    Ferguson, David K.; Zetter, Reinhard; Vavra, Norbert [Department of Paleontology, University of Vienna, Althanstrasse 14, A-1090 Vienna (Austria); Lee, Daphne E. [Department of Geology, University of Otago, PO Box 56, Dunedin (New Zealand); Bannister, Jennifer M. [Department of Botany, University of Otago, PO Box 56, Dunedin (New Zealand); Jordan, Gregory J. [School of Plant Sciences, University of Tasmania, Private Bag 55, Hobart, Tasmania 7001 (Australia); Mildenhall, Dallas C. [GNS Science, PO Box 30-368, Lower Hutt (New Zealand)

    2010-08-01

    A diverse assemblage of fossil leaves showing cellular detail is reported from the Late Oligocene-Early Miocene Gore Lignite Measures, southern New Zealand. The leaf-remains include at least five conifers, such as the genera Agathis, Dacrycarpus, Phyllocladus and Dacrydium, as well as a number of angiosperms including Gymnostoma, Nothofagus Subgenus Brassospora, Phormium, Proteaceae, Sapindaceae and Ericaceae. A parallel palynological study has identified a number of the same elements. The leaf layers represent litter horizons laid down in pools on the surface of a subtropical ombrotrophic forest mire that formed on an extensive low-lying coastal plain. Highly acidic water ponded in tree-fall depressions prevented microbial decay of the foliage. Taxa represented by both leaves and pollen are considered to have been components of the autochthonous swamp forest. Some other pollen grains are thought to represent local elements, based on the pollination biology of their nearest living relatives. Other taxa whose extant representatives are wind-pollinated may have grown further away. (author)

  5. Saccharomyces eubayanus and Saccharomyces uvarum associated with the fermentation of Araucaria araucana seeds in Patagonia.

    Science.gov (United States)

    Rodríguez, M Eugenia; Pérez-Través, Laura; Sangorrín, Marcela P; Barrio, Eladio; Lopes, Christian A

    2014-09-01

    Mudai is a traditional fermented beverage, made from the seeds of the Araucaria araucana tree by Mapuche communities. The main goal of the present study was to identify and characterize the yeast microbiota responsible of Mudai fermentation as well as from A. araucana seeds and bark from different locations in Northern Patagonia. Only Hanseniaspora uvarum and a commercial bakery strain of Saccharomyces cerevisiae were isolated from Mudai and all Saccharomyces isolates recovered from A. araucana seed and bark samples belonged to the cryotolerant species Saccharomyces eubayanus and Saccharomyces uvarum. These two species were already reported in Nothofagus trees from Patagonia; however, this is the first time that they were isolated from A. araucana, which extends their ecological distribution. The presence of these species in A. araucana seeds and bark samples, led us to postulate a potential role for them as the original yeasts responsible for the elaboration of Mudai before the introduction of commercial S. cerevisiae cultures. The molecular and genetic characterization of the S. uvarum and S. eubayanus isolates and their comparison with European S. uvarum strains and S. eubayanus hybrids (S. bayanus and S. pastorianus), allowed their ecology and evolution us to be examined. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  6. Magellanic Woodpeckers in three national parks of central-southern Chile: habitat effects and population variation over the last two decades

    Directory of Open Access Journals (Sweden)

    Pablo M. Vergara

    2017-12-01

    Full Text Available A major challenge for protected areas is providing wildlife with enough suitable habitat to cope with stochastic environment and increased pressure from the surrounding landscapes. In this study, we addressed changes in local populations of Magellanic Woodpeckers (Campephilus magellanicus occupying three national parks of central-southern Chile. We compared the breeding and postbreeding abundance of woodpeckers during the 1990s with the present (2016 abundance (n = 4 years, and assessed the extent to which abundance was explained by forest type and quality of foraging habitat (as quantified through the plant senescence reflectance index; PSRI. Results show a distinctive temporal variation in woodpecker abundance at each park, with local populations of Magellanic Woodpeckers declining by 42.2% in Conguillío National Park, but increasing by 34.3% in Nahuelbuta National Park. Woodpeckers responded to forest conditions within each park such that their abundance increased with high quality of foraging habitat, i.e., large PSRI values, and the presence of old-growth Monkey puzzle (Araucaria araucana - Nothofagus pumilio mixed forest. Anecdotal evidence suggests that populations of woodpeckers in Conguillío National Park might have responded negatively to large-scale disturbances from recent forest fires affecting part of the forest area within park. Because stochastic events seemed to strongly mediate population changes, our findings suggest that regional conservation of Magellanic Woodpeckers requires expanding the current conservation area network in central-southern Chile.

  7. Knowing and doing: research leading to action in the conservation of forest genetic diversity of Patagonian temperate forests.

    Science.gov (United States)

    Gallo, Leonardo A; Marchelli, Paula; Chauchard, Luis; Peñalba, Marcelo Gonzalez

    2009-08-01

    Researchers dealing with conservation subjects usually do not put the results of their work into practice, even when the primary purpose of their research is the preservation of biodiversity. In the South American temperate forests we identified an area with the highest genetic diversity in Argentina of Nothofagus nervosa, one of the most relevant southern beech species. Based on the information of our scientific study and our recommendations, the authorities of Lanin National Park changed the protection status of this area to avoid logging. The new forestry management plans include consideration of "high genetic diversity" in decisions on where logging will be allowed. Results of our initial genetic study induced the analysis of biodiversity at the species and ecosystems levels, which yielded results similar to our genetic studies. A strong connection among researchers and managers from the onset of our study and the awareness of the former about the importance of the implementation of the research work were key to bridging the gap between conservation research and conservation practice.

  8. Microbe domestication and the identification of the wild genetic stock of lager-brewing yeast

    Science.gov (United States)

    Libkind, Diego; Hittinger, Chris Todd; Valério, Elisabete; Gonçalves, Carla; Dover, Jim; Johnston, Mark; Gonçalves, Paula; Sampaio, José Paulo

    2011-01-01

    Domestication of plants and animals promoted humanity's transition from nomadic to sedentary lifestyles, demographic expansion, and the emergence of civilizations. In contrast to the well-documented successes of crop and livestock breeding, processes of microbe domestication remain obscure, despite the importance of microbes to the production of food, beverages, and biofuels. Lager-beer, first brewed in the 15th century, employs an allotetraploid hybrid yeast, Saccharomyces pastorianus (syn. Saccharomyces carlsbergensis), a domesticated species created by the fusion of a Saccharomyces cerevisiae ale-yeast with an unknown cryotolerant Saccharomyces species. We report the isolation of that species and designate it Saccharomyces eubayanus sp. nov. because of its resemblance to Saccharomyces bayanus (a complex hybrid of S. eubayanus, Saccharomyces uvarum, and S. cerevisiae found only in the brewing environment). Individuals from populations of S. eubayanus and its sister species, S. uvarum, exist in apparent sympatry in Nothofagus (Southern beech) forests in Patagonia, but are isolated genetically through intrinsic postzygotic barriers, and ecologically through host-preference. The draft genome sequence of S. eubayanus is 99.5% identical to the non-S. cerevisiae portion of the S. pastorianus genome sequence and suggests specific changes in sugar and sulfite metabolism that were crucial for domestication in the lager-brewing environment. This study shows that combining microbial ecology with comparative genomics facilitates the discovery and preservation of wild genetic stocks of domesticated microbes to trace their history, identify genetic changes, and suggest paths to further industrial improvement. PMID:21873232

  9. A Quantitative Index of Forest Structural Sustainability

    Directory of Open Access Journals (Sweden)

    Jonathan A. Cale

    2014-07-01

    Full Text Available Forest health is a complex concept including many ecosystem functions, interactions and values. We develop a quantitative system applicable to many forest types to assess tree mortality with respect to stable forest structure and composition. We quantify impacts of observed tree mortality on structure by comparison to baseline mortality, and then develop a system that distinguishes between structurally stable and unstable forests. An empirical multivariate index of structural sustainability and a threshold value (70.6 derived from 22 nontropical tree species’ datasets differentiated structurally sustainable from unsustainable diameter distributions. Twelve of 22 species populations were sustainable with a mean score of 33.2 (median = 27.6. Ten species populations were unsustainable with a mean score of 142.6 (median = 130.1. Among them, Fagus grandifolia, Pinus lambertiana, P. ponderosa, and Nothofagus solandri were attributable to known disturbances; whereas the unsustainability of Abies balsamea, Acer rubrum, Calocedrus decurrens, Picea engelmannii, P. rubens, and Prunus serotina populations were not. This approach provides the ecological framework for rational management decisions using routine inventory data to objectively: determine scope and direction of change in structure and composition, assess excessive or insufficient mortality, compare disturbance impacts in time and space, and prioritize management needs and allocation of scarce resources.

  10. Palynological analysis of camelid coprolites: seasonality in the use of the site Cerro Casa de Piedra 7 (Santa Cruz, Argentina)

    Science.gov (United States)

    Velázquez, Nadia Jimena; Burry, Lidia Susana; Fugassa, Martín Horacio; Civalero, María Teresa; Aschero, Carlos Alberto

    2014-01-01

    Palynological, palaeoparasitological and paleobotanical studies of coprolites found in archaeological sites from Perito Moreno National Park (47°57‧S72°05‧W) yielded information on diet, palaeoenvironment and health. These studies allowed adding evidence to the reconstruction of life history of the hunter-gatherers that inhabited Patagonia during the Holocene. We examined the season of the year when camelid Lama guanicoe coprolites (5400 ± 64 yr 14C BP to 9640 ± 190 yr 14C BP) were deposited at Cerro Casa de Piedra 7 (site CCP7). The study used palynological evidence and comparison with pollen spectra of modern feces collected during summer, fall, winter and spring of 2010. The dominant types were: pollen of Nothofagus, Empetrum rubrum, Asteraceae subfam. Asteroideae, Nassauvia, Caryophyllaceae and Poaceae; fern spores; remains of Eimeria macusaniensis; and plant remains of Poaceae, Festuca pallescens, Stipa speciosa, Armeria maritima, Gaultheria mucronata and E. rubrum. Pollen spectra of modern and fossil feces were used for multivariate analysis. Coprolites associated to fall and winter modern feces. These results and those obtained from pollen concentration values and the presence of pollen types indicators of seasonality, allowed the determination of summer, fall and winter coprolites. However, caution must be taken with the seasonality results of coprolites dated earlier than 9000 years BP since the environmental conditions differed from now. The site was probably a camelid shelter during the unfavorable seasons.

  11. Males of Hylamorpha elegans burmeister (Coleoptera: Scarabaeidae) are attracted to odors released from conspecific females.

    Science.gov (United States)

    Quiroz, Andrés; Palma, Ruben; Etcheverría, Paulina; Navarro, Vicente; Rebolledo, Ramón

    2007-04-01

    The behavioral responses of Hylamorpha elegans L. (Coleoptera: Scarabaeidae, Rutelinae) to the semiochemicals released from conspecific individual adults were studied, with particular attention paid to female attraction of males. Odors released from virgin females significantly attracted male conspecifics in both the field and laboratory olfactometer and wind tunnel bioassays. However, females did not attract other females, and males attracted no one. The response of male H. elegans to (1) compounds (1,4-hydroquinone and 1,4-benzoquinone) released only by unmated females; (2) the essential oil of the secondary host (Nothofagus obliqua); and (3) the blend of 1,4-hydroquinone and 1,4-benzoquinone with N. obliqua essential oil was studied. The blend of 1,4-benzoquinone mixed with essential oil at the trial concentration was attractive with males. The same response was found with 1,4-hydroquinone alone. The essential oil did not have the expected attractant effect on conspecific males. These results suggest that, when combined with essential oil, 1,4-benzoquinone may function in the sexual behavior of males and females. These findings are discussed in terms of the ecological role of this putative sexual pheromone and its potential use in a strategy of control of this pest.

  12. Equations of bark thickness and volume profiles at different heights with easy-measurement variables

    Energy Technology Data Exchange (ETDEWEB)

    Cellini, J. M.; Galarza, M.; Burns, S. L.; Martinez-Pastur, G. J.; Lencinas, M. V.

    2012-11-01

    The objective of this work was to develop equations of thickness profile and bark volume at different heights with easy-measurement variables, taking as a study case Nothofagus pumilio forests, growing in different site qualities and growth phases in Southern Patagonia. Data was collected from 717 harvested trees. Three models were fitted using multiple, non-lineal regression and generalized linear model, by stepwise methodology, iteratively reweighted least squares method for maximum likelihood estimation and Marquardt algorithm. The dependent variables were diameter at 1.30 m height (DBH), relative height (RH) and growth phase (GP). The statistic evaluation was made through the adjusted determinant coefficient (r2-adj), standard error of the estimation (SEE), mean absolute error and residual analysis. All models presented good fitness with a significant correlation with the growth phase. A decrease in the thickness was observed when the relative height increase. Moreover, a bark coefficient was made to calculate volume with and without bark of individual trees, where significant differences according to site quality of the stands and DBH class of the trees were observed. It can be concluded that the prediction of bark thickness and bark coefficient is possible using DBH, height, site quality and growth phase, common and easy measurement variables used in forest inventories. (Author) 23 refs.

  13. Two new Liolaemus lizards from the Andean highlands of Southern Chile (Squamata, Iguania, Liolaemidae)

    Science.gov (United States)

    Troncoso-Palacios, Jaime; Diaz, Hugo A.; Puas, German I.; Riveros-Riffo, Edvin; Elorza, Alvaro A.

    2016-01-01

    Abstract Liolaemus is a diverse genus of lizards, subdivided into two subgenera: Liolaemus (sensu stricto) and Eulaemus, distributed mainly in Chile and Argentina. The Liolaemus elongatus-kriegi complex is the most diverse group within Liolaemus (sensu stricto), especially the species closely related to Liolaemus elongatus, which form a clade currently comprising nine species. Several Chilean species of this group have been recently described, mainly from volcanoes and poorly explored mountains. Here molecular and morphological evidence are provided for a new species of the Liolaemus elongatus clade, which is characterized by its small size and lack of dorsal pattern, unusual features for the species of this group of lizards. Additionally, the lack of precloacal pores in males of Liolaemus (sensu stricto) is a trait found in few species, which do not constitute a monophyletic group. A second new southern Chilean species is also described, without precloacal pores and supported by molecular phylogenetics to be related to Liolaemus villaricensis. Both new species were found in the same locality, near a lake located in a pre-Andean zone with Araucaria and Nothofagus forest. The two species are dedicated to prominent Lonkos (tribal chiefs) of the Mapuche and Pehuenche people: Janequeo and Leftraru. Additionally, the phylogenetic results suggest that Liolaemus lonquimayensis is a synonym of Liolaemus elongatus. PMID:27920609

  14. An Updated Review of Dendrochronological Investigations in Mexico, a Megadiverse Country with a High Potential for Tree-Ring Sciences

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    Andrea C. Acosta-Hernández

    2017-05-01

    Full Text Available Dendrochronology is a very useful science to reconstruct the long-term responses of trees and other woody plants forming annual rings in response to their environment. The present review considered Mexico, a megadiverse country with a high potential for tree-ring sciences given its high climatic and environmental variability. We reviewed papers considering Mexican tree species that were published from 2001 to 2016. Most of these studies examined tree species from temperate forests, mainly in the pine and fir species. The review included 31 tree species. The most intensively sampled family and species were the Pinaceae and Douglas fir (Pseudotsuga menziessi (Mirb. Franco, respectively. Some threatened tree species were also studied. Dendrochronological investigations were mainly conducted in northern and central Mexico, with Durango being the most sampled state. The reviewed studies were mostly developed for hydroclimatic reconstructions, which were mainly based on the tree-ring width as a proxy for the climate. Tree-ring studies were carried out in both national and foreign institutions. Our review identified relevant research gaps for dendrochronologists such as: (i biomes which are still scarcely studied (e.g., tropical dry forests and (ii approaches still rarely applied to Mexican forests as dendroecology.

  15. Douglas-Fir Tussock Moth- and Douglas-Fir Beetle-Caused Mortality in a Ponderosa Pine/Douglas-Fir Forest in the Colorado Front Range, USA

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    José F. Negrón

    2014-12-01

    Full Text Available An outbreak of the Douglas-fir tussock moth, Orgyia pseudotsugata McDunnough, occurred in the South Platte River drainage on the Pike-San Isabel National Forest in the Colorado Front Range attacking Douglas-fir, Pseudotsuga menziesii (Mirb. Franco. Stocking levels, species composition, and tree size in heavily and lightly defoliated stands were similar. Douglas-fir tussock moth defoliation resulted in significant Douglas-fir mortality in the heavily defoliated stands, leading to a change in dominance to ponderosa pine, Pinus ponderosa Lawson. Douglas-fir beetle, Dendroctonus pseudotsuqae Hopkins, populations increased following the defoliation event but caused less mortality, and did not differ between heavily and lightly defoliated stands. Douglas-fir tussock moth-related mortality was greatest in trees less than 15 cm dbh (diameter at 1.4 m above the ground that grew in suppressed and intermediate canopy positions. Douglas-fir beetle-related mortality was greatest in trees larger than 15 cm dbh that grew in the dominant and co-dominant crown positions. Although both insects utilize Douglas-fir as its primary host, stand response to infestation is different. The extensive outbreak of the Douglas-fir tussock moth followed by Douglas-fir beetle activity may be associated with a legacy of increased host type growing in overstocked conditions as a result of fire exclusion.

  16. Identification case of evidence in timber tracing of Pinus radiate, using high-resolution melting (HRM) analysis.

    Science.gov (United States)

    Solano, Jaime; Anabalón, Leonardo; Encina, Francisco

    2016-03-01

    Fast, accurate detection of plant species and their hybrids using molecular tools will facilitate assessment and monitoring of timber tracing evidence. In this study the origin of unknown pine samples is determined for a case of timber theft in the region of Araucania southern Chile. We evaluate the utility of the trnL marker region for species identification applied to pine wood based on High Resolution Melting. This efficient tracing methods can be incorporated into forestry applications such as certification of origin. The object of this work was genotype identification using high-resolution melting (HRM) and trnL approaches for Pinus radiata (Don) in timber tracing evidence. Our results indicate that trnL is a very sensitive marker for delimiting species and HRM analysis was used successfully for genotyping Pinus samples for timber tracing purposes. Genotyping samples by HRM analysis with the trnL1 approach allowed us to differentiate two wood samples from the Pinaceae family: Pinus radiata (Don) and Pseudotsuga menziesii (Mirb.) Franco. The same approach with Pinus trnL wood was not able to discriminate between samples of Pinus radiata, indicating that the samples were genetically indistinguishable, possibly because they have the same genotype at this locus. Timber tracing with HRM analysis is expected to contribute to future forest certification schemes, control of illegal trading, and molecular traceability of Pinus spp. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  17. An integrated tool to assess the role of new planting in PM10 capture and the human health benefits: A case study in London

    International Nuclear Information System (INIS)

    Tiwary, Abhishek; Sinnett, Danielle; Peachey, Christopher; Chalabi, Zaid; Vardoulakis, Sotiris; Fletcher, Tony; Leonardi, Giovanni; Grundy, Chris; Azapagic, Adisa; Hutchings, Tony R.

    2009-01-01

    The role of vegetation in mitigating the effects of PM 10 pollution has been highlighted as one potential benefit of urban greenspace. An integrated modelling approach is presented which utilises air dispersion (ADMS-Urban) and particulate interception (UFORE) to predict the PM 10 concentrations both before and after greenspace establishment, using a 10 x 10 km area of East London Green Grid (ELGG) as a case study. The corresponding health benefits, in terms of premature mortality and respiratory hospital admissions, as a result of the reduced exposure of the local population are also modelled. PM 10 capture from the scenario comprising 75% grassland, 20% sycamore maple (Acer pseudoplatanus L.) and 5% Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) was estimated to be 90.41 t yr -1 , equating to 0.009 t ha -1 yr -1 over the whole study area. The human health modelling estimated that 2 deaths and 2 hospital admissions would be averted per year. - A combination of models can be used to estimate particulate matter concentrations before and after greenspace establishment and the resulting benefits to human health.

  18. Vine maple (Acer circinatum) clone growth and reproduction in managed and unmanaged coastal Oregon douglas-fir forests

    Science.gov (United States)

    O'Dea, Mary E.; Zasada, John C.; Tappeiner, John C.

    1995-01-01

    Vine maple (Acer circinatum Pursh.) clone development, expansion, and regeneration by seedling establishment were studied in 5-240 yr old managed and unmanaged Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) stands in coastal Oregon. Stem length, number of stems, and crown area were all significantly (P @10 m long and basal sprouts 1-2 m long; some stems had been pinned to the forest floor by fallen trees or branches and had layered. In stands >120 yr in age, clones were often quite complex, composed of several decumbent stems each of which connected the ramets of 1-10 new aerial stems. Vine maple clone expansion occurs by the layering of long aerial stems. Over 95% of the layered stems we observed had been pinned to the forest floor by fallen debris. Unsevered stems that we artificially pinned to the forest floor initiated roots within 1 yr. Thinning may favor clonal expansion because fallen slash from thinning often causes entire clones to layer, not just individual stems. Clonal vine maple seed production and seedling establishment occurred in all stages of stand development except dense, young stands following crown closure. There were more seedlings in thinned stands than in unthinned stands and in unburned clearcuts than in burned clearcuts.

  19. Building Resilience into Sitka Spruce (Picea sitchensis (Bong. Carr. Forests in Scotland in Response to the Threat of Climate Change

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    Andrew D. Cameron

    2015-02-01

    Full Text Available It is expected that a warming climate will have an impact on the future productivity of European spruce forests. In Scotland, Sitka spruce (Picea sitchensis (Bong. Carr. dominates the commercial forestry sector and there is growing pressure to develop alternative management strategies to limit potential economic losses through climate change. This review considers management options to increase the resilience of Sitka spruce dominated forests in Scotland. Given the considerable uncertainty over the potential long-term impacts of climate change, it is recommended that Sitka spruce should continue to be planted where it already grows well. However, new planting and restocking should be established in mixtures where silviculturally practicable, even if no-thin regimes are adopted, to spread future risks of damage. Three potentially compatible species with Sitka spruce are western hemlock (Tsuga heterophylla (Raf. Sarg., grand fir (Abies grandis (Lamb. Lindl. and Douglas fir (Pseudotsuga menziesii (Mirb. Franco and all form natural mixtures in its native range in North America. The predicted windier climate will require a range of management inputs, such as early cutting of extraction racks and early selective thinning, to improve stability. The potential to improve resilience to particularly abiotic damage through transforming even-aged stands into irregular structures and limiting the overall size of the growing stock is discussed.

  20. Douglas-fir displays a range of growth responses to ...

    Science.gov (United States)

    Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) growth in the Pacific Northwest is affected by climatic, edaphic factors and Swiss needle cast (SNC) disease. We examine Douglas-fir growth responses to temperature, dewpoint deficit (DPD), soil moisture, and SNC using time series intervention analysis of intra-annual tree-ring width data collected at nine forest stands in western Oregon, USA. The effects of temperature and SNC were similar in importance on tree growth at all sites. Previous-year DPD during the annual drought period was a key factor limiting growth regionally. Winter temperature was more important at high elevation cool sites, whereas summer temperature was more important at warm and dry sites. Growth rate increased with summer temperature to an optimum (Topt) then decreased at higher temperatures. At drier sites, temperature and water affected growth interactively such that Topt decreased with decreasing summer soil moisture. With climate change, growth rates increased at high elevation sites and declined at mid-elevation inland sites since ~1990. Growth response to climate is masked by SNC regionally. We conclude that as temperature rises and precipitation patterns shift towards wetter winters and drier summers, Douglas-fir will experience greater temperature and water stress and an increase in severity of SNC. By the end of the 21st century, climate models predict hotter, drier summers and warmer, wetter winters in the Pac

  1. Identification of varieties and gene flow in Douglas fir exemplified in artificially established stands in Germany

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    Barbara Fussi

    2013-12-01

    Full Text Available Douglas-fir [Pseudotsuga menziesii (Mirb. Franco] is an economically valuable non-native tree species in Germany and is considered very promising in view of global climate change. Therefore, the genetic characterization of Douglas-fir populations and seed stands in Germany is essential. We studied coastal and interior Douglas-fir varieties, both present in Germany, by using eleven isoenzyme and four microsatellite loci. By analyzing eight reference populations of known origin we were able to identify the two varieties on the population level using Bayesian and distance based methods. Seven populations present in Bavaria were then successfully assigned to one of the two varieties. Within varieties we found stronger grouping within the interior variety than within the coastal one. Despite lower differences within coastal Douglas-fir we have first indications for the origin of two populations. For two Bavarian populations, natural regeneration was included and genetic data revealed no significant genetic difference between adults and offspring. The parentage analysis for one of the studied stands revealed that a large proportion of adults took part in the reproduction, but some trees were more successful than others in transferring their genes to the next generation. Our study was able to improve variety identification of Douglas-fir using isoenzyme markers and nuclear microsatellites and study reproductive patterns, both are important issues for the management of Douglas-fir stands in Bavaria.

  2. Extinction Risk of Pseudotsuga Menziesii Populations in the Central Region of Mexico: An AHP Analysis

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    Javier López-Upton

    2015-05-01

    Full Text Available Within the Analytic Hierarchy Process (AHP framework, a hierarchical model was created considering anthropogenic, genetic and ecological criteria and sub-criteria that directly affect Douglas-fir (Pseudotsuga menziesii (Mirb. risk of extinction in central Mexico. The sub-criteria values were standardized, weighted, and ordered by importance in a pairwise comparison matrix; the model was mathematically integrated to quantify the degree of extinction risk for each of the 29 populations present in the study area. The results indicate diverse levels of risk for the populations, ranging from very low to very high. Estanzuela, Presa Jaramillo, Peñas Cargadas and Plan del Baile populations have very low risk, with values less than 0.25. On the other hand, Vicente Guerrero, Morán, Minatitlán, La Garita and Tonalapa populations have very high risk (>0.35 because they are heavily influenced by anthropogenic (close to roads and towns, ecological (presence of exotic species and little or no natural regeneration and genetic (presence of mature to overmature trees and geographic isolation factors. In situ conservation activities, prioritizing their implementation in populations at most risk is highly recommended; in addition, germplasm collection for use of assisted gene flow and migration approaches, including artificial reforestation, should be considered in these locations.

  3. The Douglas-Fir Genome Sequence Reveals Specialization of the Photosynthetic Apparatus in Pinaceae

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    David B. Neale

    2017-09-01

    Full Text Available A reference genome sequence for Pseudotsuga menziesii var. menziesii (Mirb. Franco (Coastal Douglas-fir is reported, thus providing a reference sequence for a third genus of the family Pinaceae. The contiguity and quality of the genome assembly far exceeds that of other conifer reference genome sequences (contig N50 = 44,136 bp and scaffold N50 = 340,704 bp. Incremental improvements in sequencing and assembly technologies are in part responsible for the higher quality reference genome, but it may also be due to a slightly lower exact repeat content in Douglas-fir vs. pine and spruce. Comparative genome annotation with angiosperm species reveals gene-family expansion and contraction in Douglas-fir and other conifers which may account for some of the major morphological and physiological differences between the two major plant groups. Notable differences in the size of the NDH-complex gene family and genes underlying the functional basis of shade tolerance/intolerance were observed. This reference genome sequence not only provides an important resource for Douglas-fir breeders and geneticists but also sheds additional light on the evolutionary processes that have led to the divergence of modern angiosperms from the more ancient gymnosperms.

  4. Palynostratigraphy and paleoenvironments of Wellington, New Zealand, during the last 80 ka, based on palynology of drillholes

    International Nuclear Information System (INIS)

    Mildenhall, D.C.

    1994-01-01

    About 20 pollen profiles from the Wellington area are correlated and zoned according to their pollen characteristics. Sequences from many of the larger sedimentary deposits are shown to contain little or no sediment of late Last Glacial and early Postglacial age, while late Postglacial sedimentation is restricted to a few localities. Sediments of middle and early Last Glacial age are well represented and widespread over the Wellington area. Pollen diagrams from Last Glacial and Postglacial sediments are zoned as follows: Zone A, 80,000-60,000 yr B.P. (lower end of range more likely) and provisionally correlated with oxygen isotope stages 5a and basal 4; Zone B, 70,000-50,000 yr B.P. (lower end of range more likely), provisionally correlated with upper oxygen isotope stages 4 and basal stage 3; Zone C, a short zone just beyond the range of radiocarbon dating at the top of Zone B of 60,000-50,000 yr B.P., correlated with the middle of oxygen isotope stage 3; Zone D, 50,000-10,000 yr B.P., with a major period of nondeposition or erosion between c. 18,000 and 10,000 yr B.P., correlated with the upper part of oxygen isotope stages 3 and all of 2; Zone E, 10,000-1000 yr B.P. (Postglacial); Zone F, last 1000 years (human occupation zone). During this time the vegetation changed from a beech forest (Zone A1) to a shrub/grassland, with pollen from the dominant tree taxa being Nothofagus fusca type (Zone A2), N. menziesii with Phyllocladus (Zones B, C), Phyllocladus with N. menziesii (Zone D), Dacrydium cupressinum (Zone E), and Nothofagus fusca with D. cupressinum (Zone F). Climatic conditions during the Last Glaciation were generally colder, drier, and stormier relative to the present day. The virtual absence of sediment of this age suggests widespread nondeposition or erosion under unstable conditions. Zones B-D represent the harshest conditions, with temperatures averaging up to 5 degrees C less than the present day. Basal Postglacial conditions were the reverse, with

  5. Estado actual del conocimiento de la familia Ceratopogonidae en la Patagonia (Diptera: Nematocera Current knowledge of the family Ceratopogonidae in Patagonia (Diptera: Nematocera

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    Gustavo R. Spinelli

    2009-06-01

    Full Text Available Ceratopogonidae incluye pequeños dípteros nematoceros que crían en hábitats acuáticos o semiacuáticos. Hasta los '80, el conocimiento de su taxonomía en la Patagonia se hallaba limitado a la contribución de los comienzos de los '30 de Ingram y Macfie, sobre la base de material capturado en 1926-27, en el área del Parque Nacional Nahuel Huapi y zonas vecinas de Chile. En los últimos 25 años, se pusieron en marcha diferentes proyectos, resultando la descripción o registro de numerosos taxones para la región. Si se contabilizan los datos publicados, 102 especies habitan en la Patagonia, de las cuales 86 (84,31% son endémicas para la región. Este alto porcentaje es evidente en los bosques de Nothofagus, con 71 especies endémicas de este bioma, nueve lo son de la estepa y seis presentan registros en bosque y estepa. Datos aún no publicados concuerdan con este esquema. Diecinueve géneros están representados en la Patagonia, diez de ellos con amplia distribución, tres de distribución transantártica y seis son endémicos para el área. Para la misma, se hallan publicadas las revisiones de Forcipomyia, Atrichopogon, Borkenthelea, Macrurohelea y Paradasyhelea; se han finalizado y aún no publicado aquellas de Dasyhelea y Palpomyia, está muy avanzada la de Stilobezzia y se prevé comenzar con las de Austrohelea, Austrosphaeromias, Physohelea y Bezzia. Se calcula que estos datos no divulgados contienen al menos 55 especies todavía no descriptas. Con respecto a los aspectos biogeográficos se pueden destacar estudios que tienden a establecer relaciones entre las áreas reconocidas en esquemas biogeográficos propuestos para la región andina.Ceratopogonidae includes small nematoceran Diptera which breed in aquatic and semiaquatic habitats. Until the 80´s its taxonomic knowledge in Patagonia was limited to the early 30´s contribution of Ingram and Macfie, from material collected in 1926-27 in the area of the Nahuel Huapi National

  6. Identificación de los mecanismos subyacentes a la invasión de Castor canadensis (Rodentia en el archipiélago de Tierra del Fuego, Chile Identifying the mechanisms underlying the invasion of Castor canadensis (Rodentia into Tierra del Fuego archipelago, Chile

    Directory of Open Access Journals (Sweden)

    PETRA K WALLEM

    2007-09-01

    Full Text Available Castor canadensis es considerado un ingeniero ecosistémico arquetípico, ya que altera el estado de factores bióticos y abióticos, mediante interacciones no tróficas, modificando sustancialmente los ecosistemas que habita. Esta especie fue introducida en la Isla Grande de Tierra del Fuego en 1946 por el gobierno argentino, con el fin de estimular la industria peletera. Actualmente se encuentra presente en las principales islas del archipiélago, incluyendo Tierra del Fuego, Navarino, Dawson y Hoste y ocupando habitat tan contrastantes como los bosques subpolares magallánicos, el matorral y la estepa patagónica. Su éxito en estos habitat sugiere que su expansión solo se verá limitada por la disponibilidad de recursos hídricos. De acuerdo a lo observado en Tierra del Fuego, en ausencia de un programa de control poblacional, los castores amenazan con establecerse en todos los bosques templados nativos del continente (entre los 35 y 55° S y ocupar los habitat de matorral y pastizal circundantes a los mismos. El presente artículo propone tres hipótesis referentes a los mecanismos subyacentes al éxito de esta invasión: el escape de enemigos naturales, la oportunidad de recursos, y la autofacilitación mediante interacciones no tróficas. Los antecedentes disponibles develan patrones conductuales (e.g., el establecimiento de colonias en forma independiente de la cercanía de recursos maderables, un aparente crecimiento poblacional irruptivo, así como una explotación centrada en Nothofagus pumilio, especie dominante en los bosques magallánicos que sugieren la operación de los mecanismos de escape de enemigos naturales y oportunidad de recursos. También se observa una mayor densidad de colonias activas en habitat que presentan mayor extensión de modificación ambiental, sugiriendo el accionar del mecanismo de autofacilitación. Si bien la información reunida no permite poner a prueba las hipótesis propuestas, sí entrega un marco

  7. Influencia de las especies del dosel en la disponibilidad de recursos y regeneración avanzada en un bosque templado lluvioso del sur de Chile Influence of overstorey species identity on resource availability and variation in composition of advanced regeneration in a temperate rainforest in southern Chile

    Directory of Open Access Journals (Sweden)

    ALFREDO SALDAÑA

    2003-12-01

    Full Text Available La heterogeneidad de hábitat en el sotobosque es un factor que promueve el mantenimiento de la diversidad de especies de la comunidad forestal. En este estudio se evaluó la influencia de cuatro especies dominantes de un bosque templado del sur de Chile, Laureliopsis philippiana, Aextoxicon punctatum, Eucryphia cordifolia y Nothofagus dombeyi, sobre la disponibilidad de recursos y su relación con la composición de la regeneración avanzada. Se estimó el porcentaje de luz difusa, la disponibilidad de nitrógeno, fósforo y calcio, el contenido de nitrógeno, fósforo y calcio de la hojarasca, y se determinó la composición de la regeneración avanzada bajo los doseles de cada una de las cuatro especies. Además, se realizó una ordenación para evaluar la variación de la composición de la regeneración avanzada. Se encontraron diferencias significativas en la transmisión de luz bajo cada especie, así como en el contenido nutricional de la hojarasca y disponibilidad de los nutrientes N-NO3 y P. Los tres nutrientes evaluados presentaron escasa disponibilidad en el suelo, debido a baja mineralización y alta inmovilización. De acuerdo a la ordenación, la composición de la regeneración avanzada bajo N. dombeyi y L. philippiana, fue distinguible de la composición de la regeneración bajo E. cordifolia y A. punctatum. La luz fue el recurso que explicó la mayor parte de la variación en la composición de la regeneración avanzada en el sotobosque. En cambio, la variación en la disponibilidad de nutrientes no tuvo relación con la especie en el dosel. Postulamos que las especies que regeneran bajo este dosel difieren más en sus requerimientos lumínicos que nutricionales, siendo la luz el recurso más limitante en el sotobosqueUnderstory habitat heterogeneity is a factor promoting maintenance of species diversity in forest communities. The influence of over storey species identity on resource availability and variation in composition of

  8. Validating numerical simulations of snow avalanches using dendrochronology: the Cerro Ventana event in Northern Patagonia, Argentina

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    A. Casteller

    2008-05-01

    Full Text Available The damage caused by snow avalanches to property and human lives is underestimated in many regions around the world, especially where this natural hazard remains poorly documented. One such region is the Argentinean Andes, where numerous settlements are threatened almost every winter by large snow avalanches. On 1 September 2002, the largest tragedy in the history of Argentinean mountaineering took place at Cerro Ventana, Northern Patagonia: nine persons were killed and seven others injured by a snow avalanche. In this paper, we combine both numerical modeling and dendrochronological investigations to reconstruct this event. Using information released by local governmental authorities and compiled in the field, the avalanche event was numerically simulated using the avalanche dynamics programs AVAL-1D and RAMMS. Avalanche characteristics, such as extent and date were determined using dendrochronological techniques. Model simulation results were compared with documentary and tree-ring evidences for the 2002 event. Our results show a good agreement between the simulated projection of the avalanche and its reconstructed extent using tree-ring records. Differences between the observed and the simulated avalanche, principally related to the snow height deposition in the run-out zone, are mostly attributed to the low resolution of the digital elevation model used to represent the valley topography. The main contributions of this study are (1 to provide the first calibration of numerical avalanche models for the Patagonian Andes and (2 to highlight the potential of Nothofagus pumilio tree-ring records to reconstruct past snow-avalanche events in time and space. Future research should focus on testing this combined approach in other forested regions of the Andes.

  9. Foraging behaviour of the exotic wasp Vespula germanica (Hymenoptera: Vespidae) on a native caterpillar defoliator.

    Science.gov (United States)

    Pietrantuono, A L; Moreyra, S; Lozada, M

    2017-09-19

    Vespula germanica is a social wasp and an opportunistic predator. While foraging, these wasps learn and integrate different kinds of cues. They have successfully invaded many parts of the world, including native Nothofagus and Lophozonia forests located in the Andean-Patagonian region, where they forage on native arthropods. Perzelia arda, a lepidopteron defoliator of Lophozonia obliqua, uses the foliage to hide in and feed on. The purpose of this work is to study whether V. germanica use olfactory cues when foraging on P. arda. To do this, we used a Y-tube olfactometer and established three treatments to compare pairs of all combinations of stimuli (larvae, leaves with larval traces, and leaves without larval traces) and controls. Data were analysed via two developed models that showed decisions made by V. germanica and allowed to establish a scale of preferences between the stimuli. The analysis demonstrates that V. germanica wasps choose P. arda as larval prey and are capable of discriminating between the offered stimuli (deviance information criterion (DIC) null model = 873.97; DIC simple model = 84.5, n = 152). According to the preference scale, V. germanica preferred leaves with traces of larvae, suggesting its ability to associate these traces with the presence of the prey. This may be because, under natural conditions, larvae are never exposed outside their shelters of leaves and therefore V. germanica uses indirect signals. The presence of V. germanica foraging on P. arda highlights the flexible foraging behaviour of this wasp which may also act as a positive biological control, reducing lepidopteran populations.

  10. Limitantes físicos y bióticos de la regeneración arbórea en matorrales sucesionales de la Isla Grande de Chiloé, Chile Physical and biotic constraints on tree regeneration in secondary shrublands of Chiloé Island, Chile

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    MARÍA F DÍAZ

    2007-03-01

    Full Text Available Los matorrales sucesionales establecidos después de la corta y quema de bosques son frecuentes en Chiloé y territorios continentales vecinos. Estos sitios son dominados por arbustos de Baccharis patagonica, musgos en cojín del género Sphagnum, plantas palustres y helechos. En estos sitios hemos registrado escasa o nula colonización arbórea (Successional shrublands created by clearcutting and burning of forests are frequent in Chiloé Island and surrounding mainland in southern Chile. These areas are characterized by seasonally waterlogged soils, and vegetation dominated by sedges, ferns and shrubs, such as Baccharis patagonica, with thick carpets of Sphagnum moss occupying the spaces between shrubs. Tree regeneration in these sites was shown to be sparse or completely lacking (< 0.3 seedlings m-2 compared with 7.2 seedlings m-2 in adjacent forests. Colonization of shade-intolerant, pioneer trees may be reduced underneath Baccharis due to crown shading and on top of Sphagnum cushions, because of unfavorable conditions for tree establishment, including low pH and soil water saturation. We evaluated differences in germination rates among pioneer tree species grown in an experimental soil moisture gradient. Seed germination percentage was low for Drimys winteri and Nothofagus nitida unrelated to humidity conditions but differed between substrates (moss vs. soil. Embothrium had higher germination and survivorship when growing on Sphagnum cushions. We also monitored seedling survival of two pioneer tree species (Embothrium coccineum and Drimys winteri transplanted directly under Baccharis shrubs, in open areas, or on moss patches. Even though survivorship of Embothrium and Drimys under Baccharis was < 40 %, in one of the study sites, there were no differences between treatments. Waterlogged soils would constraint tree regeneration on successional shrublands due to a lack of elevated substrates. However, the presence of Sphagnum cushions favors

  11. High-resolution coproecology: using coprolites to reconstruct the habits and habitats of New Zealand's extinct upland moa (Megalapteryx didinus.

    Directory of Open Access Journals (Sweden)

    Jamie R Wood

    Full Text Available Knowledge about the diet and ecology of extinct herbivores has important implications for understanding the evolution of plant defence structures, establishing the influences of herbivory on past plant community structure and composition, and identifying pollination and seed dispersal syndromes. The flightless ratite moa (Aves: Dinornithiformes were New Zealand's largest herbivores prior to their extinction soon after initial human settlement. Here we contribute to the knowledge of moa diet and ecology by reporting the results of a multidisciplinary study of 35 coprolites from a subalpine cave (Euphrates Cave on the South Island of New Zealand. Ancient DNA analysis and radiocarbon dating revealed the coprolites were deposited by the extinct upland moa (Megalapteryx didinus, and span from at least 6,368±31 until 694±30 (14C years BP; the approximate time of their extinction. Using pollen, plant macrofossil, and ancient DNA analyses, we identified at least 67 plant taxa from the coprolites, including the first evidence that moa fed on the nectar-rich flowers of New Zealand flax (Phormium and tree fuchsia (Fuchsia excorticata. The plant assemblage from the coprolites reflects a highly-generalist feeding ecology for upland moa, including browsing and grazing across the full range of locally available habitats (spanning southern beech (Nothofagus forest to tussock (Chionochloa grassland. Intact seeds in the coprolites indicate that upland moa may have been important dispersal agents for several plant taxa. Plant taxa with putative anti-browse adaptations were also identified in the coprolites. Clusters of coprolites (based on pollen assemblages, moa haplotypes, and radiocarbon dates, probably reflect specimens deposited at the same time by individual birds, and reveal the necessity of suitably large sample sizes in coprolite studies to overcome potential biases in diet interpretation.

  12. Insights into intraspecific wood density variation and its relationship to growth, height and elevation in a treeline species.

    Science.gov (United States)

    Fajardo, A

    2018-05-01

    The wood economics spectrum provides a general framework for interspecific trait-trait coordination across wide environmental gradients. Whether global patterns are mirrored within species constitutes a poorly explored subject. In this study, I first determined whether wood density co-varies together with elevation, tree growth and height at the within-species level. Second, I determined the variation of wood density in different stem parts (trunk, branch and twigs). In situ trunk sapwood, trunk heartwood, branch and twig densities, in addition to stem growth rates and tree height were determined in adult trees of Nothofagus pumilio at four elevations in five locations spanning 18° of latitude. Mixed effects models were fitted to test relationships among variables. The variation in wood density reported in this study was narrow (ca. 0.4-0.6 g cm -3 ) relative to global density variation (ca. 0.3-1.0 g cm -3 ). There was no significant relationship between stem growth rates and wood density. Furthermore, the elevation gradient did not alter the wood density of any stem part. Trunk sapwood density was negatively related to tree height. Twig density was higher than branch and trunk densities. Trunk heartwood density was always significantly higher than sapwood density. Negative across-species trends found in the growth-wood density relationship may not emerge as the aggregate of parallel intraspecific patterns. Actually, trees with contrasting growth rates show similar wood density values. Tree height, which is tightly related to elevation, showed a negative relationship with sapwood density. © 2018 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.

  13. Modelling tree ring cellulose δ18O variations in two temperature-sensitive tree species from North and South America

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    A. Lavergne

    2017-11-01

    Full Text Available Oxygen isotopes in tree rings (δ18OTR are widely used to reconstruct past climates. However, the complexity of climatic and biological processes controlling isotopic fractionation is not yet fully understood. Here, we use the MAIDENiso model to decipher the variability in δ18OTR of two temperature-sensitive species of relevant palaeoclimatological interest (Picea mariana and Nothofagus pumilio and growing at cold high latitudes in North and South America. In this first modelling study on δ18OTR values in both northeastern Canada (53.86° N and western Argentina (41.10° S, we specifically aim at (1 evaluating the predictive skill of MAIDENiso to simulate δ18OTR values, (2 identifying the physical processes controlling δ18OTR by mechanistic modelling and (3 defining the origin of the temperature signal recorded in the two species. Although the linear regression models used here to predict daily δ18O of precipitation (δ18OP may need to be improved in the future, the resulting daily δ18OP values adequately reproduce observed (from weather stations and simulated (by global circulation model δ18OP series. The δ18OTR values of the two species are correctly simulated using the δ18OP estimation as MAIDENiso input, although some offset in mean δ18OTR levels is observed for the South American site. For both species, the variability in δ18OTR series is primarily linked to the effect of temperature on isotopic enrichment of the leaf water. We show that MAIDENiso is a powerful tool for investigating isotopic fractionation processes but that the lack of a denser isotope-enabled monitoring network recording oxygen fractionation in the soil–vegetation–atmosphere compartments limits our capacity to decipher the processes at play. This study proves that the eco-physiological modelling of δ18OTR values is necessary to interpret the recorded climate signal more reliably.

  14. Antarctotrechus balli sp. n. (Carabidae, Trechini: the first ground beetle from Antarctica

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    Allan C. Ashworth

    2016-11-01

    Full Text Available Fossil elytra of a small trechine carabid are reported from the Oliver Bluffs on the Beardmore Glacier at lat. 85°S. They were compared with counterparts from the extant genera Trechisibus, Tasmanorites, Oxytrechus and Pseudocnides. The fossils share some characters but are sufficiently different to be described as a new genus and species. We named the new species Antarctotrechus balli in honour of George E. Ball who made major contributions to the study of carabids through his own research and the training of students while at the University of Alberta, Edmonton, Alberta, Canada. The closest extant relatives to the extinct A. balli are species of Trechisibus, which inhabit South America, the Falkland Islands and South Georgia, and Tasmanorites, which inhabit Tasmania, Australia. Plant fossils associated with A. balli included Nothofagus (southern beech, Ranunculus (buttercup, moss mats and cushion plants that were part of a tundra biome. Collectively, the stratigraphic relationships and the growth characteristics of the fossil plants indicate that A. balli inhabited the sparsely-vegetated banks of a stream that was part of an outwash plain at the head of a fjord in the Transantarctic Mountains. Other insects represented by fossils in the tundra biome include a listroderine weevil and a cyclorrhaphan fly. The age of the fossils, based on comparison of associated pollen with 40Ar/39Ar dated pollen assemblages from the McMurdo Dry Valleys, is probably Early to Mid-Miocene in the range 14–20 Ma. The tundra biome, including A. balli, became extinct in the interior of Antarctica about 14 Ma and on the margins of the continent by 10–13 Ma. A. balli confirms that trechines were once widely distributed in Gondwana. For A. balli and other elements of the tundra biome it appears they continued to inhabit a warmer Antarctica for many millions of years after rifting of Tasmania (45 Ma and southern South America (31 Ma.

  15. VOCES EN EL BOSQUE: EL USO DE RECURSOS VEGETALES ENTRE CAZADORES-RECOLECTORES DE LA ZONA CENTRAL DE TIERRA DEL FUEGO

    Directory of Open Access Journals (Sweden)

    Laura Caruso

    2008-01-01

    Full Text Available Se estudiaron las modalidades de aprovechamiento de las plantas entre los Selknam de Tierra del Fuego (Argentina y se presentan aquí los resultados obtenidos a partir del análisis de los restos de madera carbonizada y sin carbonizar del sitito Ewan, ocupado a principios del siglo XX para la realización de un ritual de iniciación. Los resultados permitieron una mejor comprensión de las estrategias de aprovechamiento de las plantas entre las sociedades cazadoras-recolectoras. La identificación de las especies empleadas y el registro de las principales características morfométricas permitió documentar el aprovechamiento del "ñire" (Nothofagus antarctica. Esta especie, dominante en el entorno, fue utilizada para la construcción de la vivienda y como combustible. En ambos casos se seleccionaron troncos de forma y tamaño adecuados. Los resultados del trabajo arqueobotánico y su confrontación con los datos etnográficos evidenciaron la importancia de los recursos vegetales dentro de la dinámica socioeconómica de este grupo humano. Los recursos vegetales, más allá de su rol alimentario, fueron relevantes en otros aspectos tales como la tecnología, la construcción, el combustible y debieron constituir una ventaja considerable en el ámbito de los bosques de la zona central de Tierra del Fuego.

  16. Eocene age of the Baranowski Glacier Group at Red Hill, King George Island, West Antarctica

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    Mozer Anna

    2015-12-01

    Full Text Available Radiometric and geochemical studies were carried out at Red Hill in the southern part of King George Island (South Shetland Islands, northern Antarctic Peninsula on the Bransfield Strait coast. The rock succession at Red Hill has been determined to represent the Baranowski Glacier Group that was previously assigned a Late Cretaceous age. Two formations were distinguished within this succession: the lower Llano Point Formation and the upper Zamek Formation. These formations have stratotypes defined further to the north on the western coast of Admiralty Bay. On Red Hill the Llano Point Formation consists of terrestrial lavas and pyroclastic breccia; the Zamek Formation consist predominantly of fine to coarse tuff, pyroclastic breccia, lavas, tuffaceous mud-, silt-, and sandstone, locally conglomeratic. The lower part of the Zamek Formation contains plant detritus (Nothofagus, dicotyledonous, thermophilous ferns and numerous coal seams (vitrinitic composition that confirm the abundance of vegetation on stratovolcanic slopes and surrounding lowlands at that time. Selected basic to intermediate igneous rocks from the succession have been analysed for the whole-rock K-Ar age determination. The obtained results indicate that the Red Hill succession was formed in two stages: (1 from about 51–50 Ma; and (2 46–42 Ma, i.e. during the Early to Middle Eocene. This, in combination with other data obtained from other Baranowski Glacier Group exposures on western coast of Admiralty Bay, confirms the recently defined position of the volcano-clastic succession in the stratigraphic scheme of King George Island. The new stratigraphic position and lithofacies development of the Red Hill succession strongly suggest its correlation with other Eocene formations containing fossil plants and coal seams that commonly occur on King George Island.

  17. Lichen Persistence and Recovery in Response to Varied Volcanic Disturbances

    Science.gov (United States)

    Nelson, P.; Wheeler, T. B.

    2015-12-01

    Volcanic eruptions produce many ecological disturbances that structure vegetation. While lichens are sensitive to disturbances, little is known about their responses to volcanic disturbances, except for colonization of lava. We examined lichen community responses through time to different disturbances produced by the May 1, 2008 eruption of Volcan Chaiten in south-central Chile. Pre-eruption vegetation near the volcano was old-growth Valdivian temperate rainforest dominated by closed-canopy Nothofagus sp... In 2012, we installed thirteen 1-acre plots across volcanic disturbance zones on which a time-constrained search was done for all macrolichen species, each of which was assigned an approximate log10 categorical abundance. We also installed a 0.2 m2 quadrat on two representative trees per plot for repeat photography of lichen cover. We remeasured at least one plot per disturbance zone in 2014 and re-photographed tree quadrats in 2013 and 2014. We then analyzed species composition and abundance differences among disturbance zones. In 2012, the blast (pyroclastic density flow), scorch (standing scorched forest at the edge of the blast) and deep tephra (>10 cm) zones had the lowest lichen species richness (5-13 species), followed by reference (unimpacted) and shallow (lichen species since 2012 while the light tephra and reference were essentially unchanged. Gravel rain, gravel rain + pumice and flooded forest plots all had about the same number of species in 2014 as 2012. Lichen colonization and growth in tree quadrats varied widely, from very little colonization in the blast to prolific colonization in the gravel rain + pumice zone. Lichen's varied responses to different volcanic disturbances were attributable to varying degrees of mortality and subsequent availability of substrate, quantity of light and removal of competitors. While sensitive to disturbance, lichens are apparently resilient to and can quickly recolonize after a variety of large, violent volcanic

  18. Improvement of isotope-based climate reconstructions in Patagonia through a better understanding of climate influences on isotopic fractionation in tree rings

    Science.gov (United States)

    Lavergne, Aliénor; Daux, Valérie; Villalba, Ricardo; Pierre, Monique; Stievenard, Michel; Srur, Ana Marina

    2017-02-01

    Very few studies of stable isotopes exist across the Andes in South America. This study is the first presenting annually resolved chronologies of both δ18 O and δ13 C in Nothofagus pumilio and Fitzroya cupressoides trees from Northern Patagonia. Interannual variability in δ18 O and δ13 C was assessed over the period 1952-2011. Based on these chronologies, we determined the primary climatic controls on stable isotopes and tree physiological responses to changes in atmospheric CO2 concentrations (ca), temperature and humidity. Changes in specific intrinsic water use efficiency (iWUE) were inferred from variations in δ13 C whereas the effects of CO2 increase on stomatal conductance were explored using δ18 O. Over the 60-year period, iWUE increased significantly (by ca. 25%) in coincidence with the rise of ca. The two species appear to have different strategies of gas-exchange. Whereas iWUE variations were likely driven by both stomatal conductance and photosynthetic assimilation rates in F. cupressoides, they were largely related to stomatal conductance in N. pumilio. After removing the low-frequency trends related to increasing ca, significant relationships between δ13 C and summer temperatures were recorded for both species. However, δ13 C variations in F. cupressoides were more strongly influenced by summer temperatures than in N. pumilio. Our results advocate for an indirect effect of summer temperatures on stable isotope ratios, which is mostly influenced by sunlight radiation in F. cupressoides and relative humidity/soil moisture in N. pumilio. δ13 C variations in F. cupressoides were spatially correlated to a large area south of 35°S in southern South America. These promising results encourage the use of δ13 C variations in F. cupressoides for reconstructing past variations in temperature and large-scale circulation indexes such as the Southern Annular Mode (SAM) in the Southern Hemisphere.

  19. Deglacial palaeoclimate at Puerto del Hambre, subantarctic Patagonia, Chile

    Science.gov (United States)

    Heusser, Calvin J.; Heusser, Linda E.; Lowell, Thomas V.; Moreira M., Andrés; Moreira M., Simón

    2000-02-01

    The primary objective of this study is to further substantiate multistep climatic forcing of late-glacial vegetation in southern South America. A secondary objective is to establish the age of deglaciation in Estrecho de Magallanes-Bahía Inútil. Pollen assemblages at 2-cm intervals in a core of the mire at Puerto del Hambre (53°3621S, 70°5553W) provide the basis for reconstructing the vegetation and a detailed account of palaeoclimate in subantarctic Patagonia. Chronology over the 262-cm length of core is regulated by 20 AMS radiocarbon dates between 14 455 and 10 089 14C yr BP. Of 13 pollen assemblage zones, the earliest representing the Oldest Dryas chronozone (14 455-13 000 14C yr BP) records impoverished steppe with decreasing frequencies and loss of southern beech (Nothofagus). Successive 100-yr-long episodes of grass/herbs and of heath (Empetrum/Ericaceae) before 14 000 14C yr BP infer deglacial successional communities under a climate of increased continentality prior to the establishment of grass-dominated steppe. The Bølling-Allerød (13 000-11 000 14C yr BP) is characterised by mesic grassland under moderating climate that with abrupt change to heath dominance after 12 000 14C yr BP was warmer and not as humid. At the time of the Younger Dryas (11 000-10 000 14C yr BP), grass steppe expanded with a return of colder, more humid climate. Later, with gradual warming, communities were invaded by southern beech. The Puerto del Hambre record parallels multistep, deglacial palaeoclimatic sequences reported elsewhere in the Southern Andes and at Taylor Dome in Antarctica. Deglaciation of Estrecho de Magallanes-Bahía Inútil is dated close to 14 455 14C yr BP, invalidating earlier dates of between 15 800 and 16 590 14C yr BP.

  20. Late Holocene vegetation dynamics and lake geochemistry at Laguna Miranda, XI Region, Chile Dinámica vegetaciónal y geoquímica lacustre del Holoceno tardío en Laguna Miranda, XI Región, Chile

    Directory of Open Access Journals (Sweden)

    S. G. HABERLE

    2000-12-01

    Full Text Available Palynological and geochemical analysis of late Holocene lake sediments and dendrochronological analysis of Pilgerodendron in a volcanically active region of southern Chile reveal the long-term impact of a series of tephra fall events and tectonic activity on lake sedimentation and local vegetation. An upper 0,75 m core overlaps with a 4,35 m long Livingstone piston core to give a 4,60 m long sediment record, extending back to 4800 yr BP. Geochemical data shows the shift from allogenic dominance to authigenic and biogenic dominance as waterlogged soils developed within the catchment. This is presumed to have occurred under the influence of continued addition of nutrients to the catchment from tephra deposition and the associated high sedimentation rates. The palynological record from this site is dominated by Nothofagus dombeyi-type and Filicales. The most prominent changes in the pollen record, however, are the gradual decline in Podocarpus nubigena pollen throughout the last 4800 yr; the appearance and increase of Gramineae pollen during the past 2100 yr; and the rapid increase in the pollen of Pilgerodendron uviferum within the past 300-400 yr. Pilgerodendron tree-ring analysis and the pollen results over the last 400 years show that the most recent expansion of Pilgerodendron at the northern and eastern margins of this site is a response to either, periodic tectonic induced watertable changes, or is part of a long-term trend in gymnosperm growth around a shallowing lake margin. The decline of shade-intolerant trees such as Weinmannia and Podocarpus within a Nothofagus-rich forest community towards an increased presence of Pilgerodendron and Gramineae (likely Chusquea bamboo, that began over 2100 yr BP, may have been due as much to autogenic processes such as a change in the disturbance regime resulting in the development of waterlogged soils, rather than to an episode of climate change. It is important to recognise the potential effects of

  1. Ethanol synthesis and aerobic respiration in the laboratory by leader segments of Douglas-fir seedlings from winter and spring.

    Science.gov (United States)

    Joseph, Gladwin; Kelsey, Rick G

    2004-05-01

    Stem segments from terminal leaders of Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, seedlings were sampled in mid-December when cambial cells were dormant. The residual, debudded leaders were resampled again in early May when the cambium was metabolically active. May stems had higher constitutive ethanol concentrations than December stems. This was not the result of cambial hypoxia generated by rapid spring respiration rates, because when aerobic respiration was stimulated by incubating the stems in air at 30 degrees C ethanol production was induced in December, but not in May. Rapid respiration rates at 30 degrees C may have depleted O(2) supplies and induced ethanol production in December stems because dormant, thick-walled cambial cells may be less permeable to CO(2) and O(2), compared with metabolically active, thin-walled cambial cells in May. December stem segments incubated in a N(2) atmosphere at 30 degrees C synthesized 1.8 times more ethanol than segments from May, most likely because spring growth had reduced the soluble sugars available for fermentation. CO(2) efflux from May stems (after 5.5 h of incubation at 30 degrees C) was equal to December stems per unit volume, but greater than December stems per unit surface area. N(2)-induced ethanol concentrations were positively related with CO(2) efflux per unit volume, indicating that rapidly respiring leaders can maintain rapid fermentation rates, provided soluble sugars are readily available. N(2)-induced ethanol and CO(2) efflux per unit volume declined with increasing leader diameter in both seasons, whereas there were no relationships between CO(2) efflux per unit surface area and diameter. Cambium physiology and phenology influence the induction of fermentation and concentrations of ethanol produced in terminal leaders of Douglas-fir, and probably other conifers as well. This needs to be considered when comparing fermentation among species, or comparing individuals from different seasons, or

  2. Ensemble classification of individual Pinus crowns from multispectral satellite imagery and airborne LiDAR

    Science.gov (United States)

    Kukunda, Collins B.; Duque-Lazo, Joaquín; González-Ferreiro, Eduardo; Thaden, Hauke; Kleinn, Christoph

    2018-03-01

    Distinguishing tree species is relevant in many contexts of remote sensing assisted forest inventory. Accurate tree species maps support management and conservation planning, pest and disease control and biomass estimation. This study evaluated the performance of applying ensemble techniques with the goal of automatically distinguishing Pinus sylvestris L. and Pinus uncinata Mill. Ex Mirb within a 1.3 km2 mountainous area in Barcelonnette (France). Three modelling schemes were examined, based on: (1) high-density LiDAR data (160 returns m-2), (2) Worldview-2 multispectral imagery, and (3) Worldview-2 and LiDAR in combination. Variables related to the crown structure and height of individual trees were extracted from the normalized LiDAR point cloud at individual-tree level, after performing individual tree crown (ITC) delineation. Vegetation indices and the Haralick texture indices were derived from Worldview-2 images and served as independent spectral variables. Selection of the best predictor subset was done after a comparison of three variable selection procedures: (1) Random Forests with cross validation (AUCRFcv), (2) Akaike Information Criterion (AIC) and (3) Bayesian Information Criterion (BIC). To classify the species, 9 regression techniques were combined using ensemble models. Predictions were evaluated using cross validation and an independent dataset. Integration of datasets and models improved individual tree species classification (True Skills Statistic, TSS; from 0.67 to 0.81) over individual techniques and maintained strong predictive power (Relative Operating Characteristic, ROC = 0.91). Assemblage of regression models and integration of the datasets provided more reliable species distribution maps and associated tree-scale mapping uncertainties. Our study highlights the potential of model and data assemblage at improving species classifications needed in present-day forest planning and management.

  3. Variation in water potential, hydraulic characteristics and water source use in montane Douglas-fir and lodgepole pine trees in southwestern Alberta and consequences for seasonal changes in photosynthetic capacity.

    Science.gov (United States)

    Andrews, Shilo F; Flanagan, Lawrence B; Sharp, Eric J; Cai, Tiebo

    2012-02-01

    Tree species response to climate change-induced shifts in the hydrological cycle depends on many physiological traits, particularly variation in water relations characteristics. We evaluated differences in shoot water potential, vulnerability of branches to reductions in hydraulic conductivity, and water source use between Pinus contorta Dougl. ex Loud. var. latifolia Engelm. (lodgepole pine) and Pseudotsuga menziesii (Mirb.) Franco (interior Douglas-fir), and determined the consequences for seasonal changes in photosynthetic capacity. The Douglas-fir site had soil with greater depth, finer texture and higher organic matter content than soil at the lodgepole pine site, all factors that increased the storage of soil moisture. While the measured xylem vulnerability curves were quite similar for the two species, Douglas-fir had lower average midday shoot water potentials than did lodgepole pine. This implied that lodgepole pine exhibited stronger stomatal control of transpiration than Douglas-fir, which helped to reduce the magnitude of the water potential gradient required to access water from drying soil. Stable hydrogen isotope measurements indicated that Douglas-fir increased the use of groundwater during mid-summer when precipitation inputs were low, while lodgepole pine did not. There was a greater reduction of photosynthetic carbon gain in lodgepole pine compared with Douglas-fir when the two tree species were exposed to seasonal declines in soil water content. The contrasting patterns of seasonal variation in photosynthetic capacity observed for the two species were a combined result of differences in soil characteristics at the separate sites and the inherent physiological differences between the species.

  4. Tree-growth analyses to estimate tree species' drought tolerance.

    Science.gov (United States)

    Eilmann, Britta; Rigling, Andreas

    2012-02-01

    Climate change is challenging forestry management and practices. Among other things, tree species with the ability to cope with more extreme climate conditions have to be identified. However, while environmental factors may severely limit tree growth or even cause tree death, assessing a tree species' potential for surviving future aggravated environmental conditions is rather demanding. The aim of this study was to find a tree-ring-based method suitable for identifying very drought-tolerant species, particularly potential substitute species for Scots pine (Pinus sylvestris L.) in Valais. In this inner-Alpine valley, Scots pine used to be the dominating species for dry forests, but today it suffers from high drought-induced mortality. We investigate the growth response of two native tree species, Scots pine and European larch (Larix decidua Mill.), and two non-native species, black pine (Pinus nigra Arnold) and Douglas fir (Pseudotsuga menziesii Mirb. var. menziesii), to drought. This involved analysing how the radial increment of these species responded to increasing water shortage (abandonment of irrigation) and to increasingly frequent drought years. Black pine and Douglas fir are able to cope with drought better than Scots pine and larch, as they show relatively high radial growth even after irrigation has been stopped and a plastic growth response to drought years. European larch does not seem to be able to cope with these dry conditions as it lacks the ability to recover from drought years. The analysis of trees' short-term response to extreme climate events seems to be the most promising and suitable method for detecting how tolerant a tree species is towards drought. However, combining all the methods used in this study provides a complete picture of how water shortage could limit species.

  5. Competitive relations between Douglas-fir and Pacific madrone on shallow soils in a Mediterranean climate

    Science.gov (United States)

    Wang, Zheng Q.; Newton, M.; Tappeiner, J. C.

    1995-01-01

    A large area of Pacific Coast forests is characterized by shallow soil, with negligible rainfall in the growing season. This study explores water-seeking strategy on such a site. We studied availability of bedrock water and its effects on growth and ecophysiology of 11-yr-old planted Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) and sprouting Pacific madrone (Arbutus menziesii Pursh). The study was carried out at three regulated densities of madrone sprouts on shallow ( 0.05) among three densities of madrone. However, cover in plots with the highest density of madrone (1322 sprout clumps/ha) depleted 50 mm of water from the 1.5 m layer by June, whereas vegetation on lower density treatments withdrew 15-28 mm by June, with later withdrawal distributed more uniformly through the growing season. Madrone density significantly affected basal diameter (P a?? 0.0001) and height growth (P a?? 0.002) of Douglas-fir. Madrone was consistently taller than Douglas-fir in all plots. The height of 11-yr-old madrone sprout clumps (424-465 cm) did not differ significantly among densities. Madrone leaf area index and biomass were higher at the high density of madrone than at medium density (P a?? 0.045, LAI; P a?? 0.001, biomass). Physiological advantages and rooting habits of madrone give it a competitive advantage over Douglas-fir in this area that it might not have if bedrock did not provide the principal water reservoir for summer growth.

  6. Response of old-growth conifers to reduction in stand density in western Oregon forests

    Science.gov (United States)

    Latham, P.; Tappeiner, J. C.

    2002-01-01

    The positive growth response of healthy young trees to density reduction is well known. In contrast, large old trees are usually thought to be intrinsically limited in their ability to respond to increased growing space; therefore, density reduction is seldom used in stands of old-growth trees. We tested the null hypothesis that old-growth trees are incapable of responding with increased growth following density reduction. The diameter growth response of 271 Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), ponderosa pine (Pinus ponderosa Dougl. ex Laws) and sugar pine (Pinus lambertiana Dougl.) trees ranging in age from 158 to 650 years was examined 20 to 50 years after density reduction. Density reduction involved either light thinning with removal of less vigorous trees, or shelterwood treatments in which overstory trees were not removed. Ratios of basal area growth after treatment to basal area growth before treatment, and several other measures of growth, all indicated that the old trees sometimes benefited and were not harmed by density reduction. Growth increased by 10% or more for 68% of the trees in treated stands, and nearly 30% of trees increased growth by over 50%. This growth response persisted for at least 20 years. During this 20-year period, only three trees in treated stands (1.5%) exhibited a rapid decrease in growth, whereas growth decreased in 64% of trees in untreated stands. The length of time before a growth response to density reduction occurred varied from 5 to 25 years, with the greatest growth response often occurring 20 to 25 years after treatment. These results have important implications both for the basic biology of aging in woody plants as well as for silvicultural practices in forests with old-growth trees.

  7. Species distribution models may misdirect assisted migration: insights from the introduction of Douglas-fir to Europe.

    Science.gov (United States)

    Boiffin, Juliette; Badeau, Vincent; Bréda, Nathalie

    2017-03-01

    Species distribution models (SDMs), which statistically relate species occurrence to climatic variables, are widely used to identify areas suitable for species growth under future climates and to plan for assisted migration. When SDMs are projected across times or spaces, it is assumed that species climatic requirements remain constant. However, empirical evidence supporting this assumption is rare, and SDM predictions could be biased. Historical human-aided movements of tree species can shed light on the reliability of SDM predictions in planning for assisted migration. We used Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), a North American conifer introduced into Europe during the mid-19th century, as a case-study to test niche conservatism. We combined transcontinental data sets of Douglas-fir occurrence and climatic predictors to compare the realized niches between native and introduced ranges. We calibrated a SDM in the native range and compared areas predicted to be climatically suitable with observed presences. The realized niches in the native and introduced ranges showed very limited overlap. The SDM calibrated in North America had very high predictive power in the native range, but failed to predict climatic suitability in Europe where Douglas-fir grows in climates that have no analogue in the native range. We review the ecological mechanisms and silvicultural practices that can trigger such shifts in realized niches. Retrospective analysis of tree species introduction revealed that the assumption of niche conservatism is erroneous. As a result, distributions predicted by SDM are importantly biased. There is a high risk that assisted migration programs may be misdirected and target inadequate species or introduction zones. © 2016 by the Ecological Society of America.

  8. Forest restoration at Redwood National Park: exploring prescribed fire alternatives to second-growth management: a case study

    Science.gov (United States)

    Engber, Eamon; Teraoka, Jason; van Mantgem, Phillip J.

    2017-01-01

    Almost half of Redwood National Park is comprised of second-growth forests characterized by high stand density, deficient redwood composition, and low understory biodiversity. Typical structure of young redwood stands impedes the recovery of old-growth conditions, such as dominance of redwood (Sequoia sempervirens (D. Don) Endl.), distinct canopy layers and diverse understory vegetation. Young forests are commonly comprised of dense, even-aged Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and redwood stump sprouts, with simple canopy structure and little understory development. Moreover, many of these young stands are believed to be vulnerable to disturbance in the form of drought, disease and fire. Silvicultural practices are increasingly being employed by conservation agencies to restore degraded forests throughout the coast redwood range; however, prescribed fire treatments are less common and potentially under-utilized as a restoration tool. We present an early synthesis from three separate management-scale prescribed fire projects at Redwood National Park spanning 1to 7 years post-treatment. Low intensity prescribed fire had minimal effect on overstory structure, with some mortality observed in trees smaller than 30 cm diameter. Moderate to high intensity fire may be required to reduce densities of larger Douglas-fir, the primary competitor of redwood in the Park’s second growth forests. Fine woody surface fuels fully recovered by 7 years post-burn, while recruitment of larger surface fuels was quite variable. Managers of coastal redwood ecosystems will benefit by having a variety of tools at their disposal for forest restoration and management.

  9. A Geochemical and Sedimentary Record of High Southern Latitude Holocene Climate Evolution from Lago Fagnano, Tierra del Fuego

    Energy Technology Data Exchange (ETDEWEB)

    Moy, C M; Dunbar, R B; Guilderson, T P; Waldmann, N; Mucciarone, D A; Recasens, C; Austin, J A; Anselmetti, F S

    2010-11-19

    Situated at the southern margin of the hemispheric westerly wind belt and immediately north of the Antarctic Polar Frontal zone, Tierra del Fuego is well-positioned to monitor coupled changes in the ocean-atmosphere system of the high southern latitudes. Here we describe a Holocene paleoclimate record from sediment cores obtained from Lago Fagnano, a large lake in southern Tierra del Fuego at 55{sup o}S, to investigate past changes in climate related to these two important features of the global climate system. We use an AMS radiocarbon chronology for the last 8,000 years based on pollen concentrates, thereby avoiding contamination from bedrock-derived lignite. Our chronology is consistent with a tephrochronologic age date for deposits from the middle Holocene Volcan Hudson eruption. Combining bulk organic isotopic ({delta}{sup 13}C and {delta}{sup 15}N) and elemental (C and N) parameters with physical sediment properties allow us to better understand sediment provenance and transport mechanisms and to interpret Holocene climate and tectonic change during the last 8,000 years. Co-variability and long-term trends in C/N ratio, carbon accumulation rate, and magnetic susceptibility reflect an overall Holocene increase in the delivery of terrestrial organic and lithogenic material to the deep eastern basin. We attribute this variability to westerly wind-derived precipitation. Increased wind strength and precipitation in the late Holocene drives the Nothofagus forest eastward and enhances run-off and terrigenous inputs to the lake. Superimposed on the long-term trend are a series of abrupt 9 negative departures in C/N ratio, which constrain the presence of seismically-driven mass flow events in the record. We identify an increase in bulk {delta}{sup 13}C between 7,000 and 5,000 cal yr BP that we attribute to enhanced aquatic productivity driven by warmer summer temperatures. The Lago Fagnano {delta}{sup 13}C record shows similarities with Holocene records of sea surface

  10. Reconstrucción espacial y temporal de la ocurrencia de avalanchas de nieve en los Andes patagónicos utilizando técnicas dendrocronológicas Dendrochronological reconstruction of spatial and temporal patterns of snow avalanches in the Patagonian Andes

    Directory of Open Access Journals (Sweden)

    ALEJANDRO CASTELLER

    2009-06-01

    Full Text Available Las avalanchas de nieve representan un importante riesgo natural en diversas regiones montañosas alrededor del mundo. Daños a infraestructura y pérdidas de vidas humanas son reportados frecuentemente en relación a eventos catastróficos de avalanchas. En los Andes, numerosas obras de infraestructura se ubican en zonas vecinas a senderos de avalanchas, de las que poco se conoce sobre sus alcances máximos, periodos de retorno y presiones de impacto. A través de la implementación de técnicas dendrocronológicas hemos reconstruido las fechas de ocurrencia y áreas de influencia de eventos pasados de avalanchas de nieve. Ejemplares de Nothofagus pumilio con perturbaciones visibles de avalanchas fueron muestreados en sectores del canal, bordes y zonas de frenado de 11 senderos de avalanchas ubicados en Loma de las Pizarras, próximo a El Chaltén, Santa Cruz, Argentina. Además, áreas de control fueron muestreadas para determinar las condiciones de crecimiento en árboles no afectados por avalanchas. Nuestros análisis indican que las cicatrices, las variaciones de excentricidad en el leño, los cambios abruptos de crecimiento y la presencia de leño de tensión son los principales indicadores dendrocronológicos en N. pumilio asociados a la ocurrencia de avalanchas. Basados en una ponderación cuantitativa de los indicadores y en la profundidad de muestreo, calculamos un índice de ocurrencia de eventos, el cual nos permitió determinar para cada sendero los años con ocurrencia de avalanchas. Considerando de manera integral la actividad de avalanchas en los 11 senderos muestreados, los años con mayor ocurrencia de eventos fueron 1936, 1966, 1978 y 1995. Complementariamente, registros climáticos fueron analizados con el objetivo de determinar las relaciones entre los años con ocurrencia de avalanchas y las variaciones mensuales de precipitación y temperatura. Se observa que los años con gran frecuencia de avalanchas est

  11. The Neogene Environment of the Beardmore Glacier, Transantarctic Mountains

    Science.gov (United States)

    Ashworth, A. C.; Cantrill, D. J.; Francis, J. E.; Roof, S. R.

    2004-12-01

    , the absence of solar heating for about 5.5 months, even though there would have been additional heat from open water in the fjord, would have resulted in a low mean annual temperature. Mean summer temperatures, based on the minimal thermal requirements for Nothofagus, listroderine weevils, and freshwater molluscs, are estimated to have been between 4 and 5°C for at least two summer months. The research is supported by NSF grant OPP-0230696

  12. Register of the last 1000 years of environmental, climatic and anthropogenic change in Isla Grande de Chiloé, inferred through a multi-proxy approach: Lake Pastahué, Chile-South Center (42°S)

    Science.gov (United States)

    Troncoso, Jose; Alvarez, Denisse; Díaz, Gustavo; Fierro, Pablo; Araneda, Alberto; Torrejón, Fernando; Rondanelli, Mauricio; Fagel, Nathalie; Urrutia, Roberto

    2017-04-01

    Knowledge of the past environmental and climatic conditions of the lake ecosystems of the Isla Grande de Chiloé and its relationship with the anthropic effect, on a high temporal resolution scale, is scarcely known. Specifically, multi-proxy studies provide a better understanding of the context in which changes occurred in the past. This insular region is particularly interesting because environmental conditions (pre and post-Hispanic) and knowledge about the impacts generated in the ecosystems during the Spanish colonization process have so far been little studied, compared to the rest of Chile continental. This research is a new contribution to the scarce information existing for the last millennium of the Isla Grande de Chiloé. The objective of this work was to reconstruct the environmental and climatic history of the last 1000 years, from the Lake Pastahué, in the Isla Grande de Chiloé through a multi-proxy analysis and compare them with other records for the region. The core sediment was sub-sampled to perform sedimentological analysis (organic matter, carbonates, magnetic susceptibility and granulometry) and biological indicators (pollen, chironomids). The age model was constructed from the activity of 210Pb,137Cs and 14C. The pollen results reveal a composition of nordpatagónico forest represented by Nothofagus, Weinmannia, Drimys, Tepualia, Myrtaceae, Poaceae and Pteridophyta, while the anthropic effect for the last cm of the profile is represented by Rumex and Pinus. The results show a significant increase in magnetic susceptibility since the middle of the 20th century, suggesting an increase in allochthonous material to the lake. The sedimentological parameters and the chironomid assembly show similar variations along the profile, which also shows changes in the trophic state of the lake. The changes recorded in lake Pastahue are directly related to past climatic phenomena occurring in the last millennium, such as the medieval climatic anomaly (MCA

  13. Estado actual del conocimiento de la familia Ceratopogonidae en la Patagonia (Diptera: Nematocera

    Directory of Open Access Journals (Sweden)

    Gustavo R. SPINELLI

    2009-01-01

    Full Text Available Ceratopogonidae incluye pequeños dípteros nematocerosque crían en hábitats acuáticos o semiacuáticos. Hasta los ‘80, el conocimiento de su taxonomía en la Patagonia se hallaba limitado a la contribución de los comienzos de los ‘30 de Ingram y Macfie, sobre la base de material capturado en 1926-27, en el área del Parque Nacional Nahuel Huapi y zonas vecinasde Chile. En los últimos 25 años, se pusieron en marcha diferentes proyectos, resultando la descripción o registro de numerosos taxones para la región. Si se contabilizan los datos publicados, 102 especies habitan en la Patagonia, de las cuales 86 (84,31% son endémicas para la región. Este alto porcentaje es evidente en los bosques de Nothofagus, con 71 especies endémicas de estebioma, nueve lo son de la estepa y seis presentan registros en bosque y estepa. Datos aún no publicados concuerdan con este esquema. Diecinueve géneros están representados en la Patagonia, diez de ellos con amplia distribución,tres de distribución transantártica y seis son endémicos para el área. Para la misma, se hallan publicadas las revisiones de Forcipomyia, Atrichopogon, Borkenthelea, Macrurohelea y Paradasyhelea; se han finalizado y aún no publicado aquellas de Dasyhelea y Palpomyia, está muy avanzada la de Stilobezzia y se prevé comenzar con las de Austrohelea, Austrosphaeromias, Physohelea y Bezzia. Se calcula que estos datos no divulgados contienen al menos 55 especies todavía no descriptas. Con respecto a los aspectos biogeográficos se pueden destacar estudios que tienden a establecer relaciones entre las áreas reconocidas en esquemas biogeográficos propuestos para la región andina.

  14. LA GEOPEDOLOGIA COMO BASE PARA ZONIFICAR LA APTITUD FORESTAL EN UNA CUENCA DEL NOROESTE DE LA PATAGONIA ARGENTINA

    Directory of Open Access Journals (Sweden)

    Maria Cristina Frugoni

    2016-12-01

    Full Text Available Geopedology at a semi-detailed scale (1:50.000 was carried out in Buta Mallín catchment which includes an area of 21.065ha, in the northwest of Neuquén province, Argentine Patagonia. Geopedology provides a spatial dimension of soil-landscape relations, which are displayed in a map and its legend, showing the geoforms (contours and their soils (content, based on the premise that soil is landscape as well as profile. According to this approach three landscapes were recognized: glacial modeled mountains, plateau and valley. The relief consists mainly of steep to very steep slopes, and valley bottoms with poorly drained soils. Lithology (parent material corresponds to holocene volcanic ash in the western sector of the study area, while the eastern sector is dominated by tuff. Twenty terrain forms and their soils were identified. With this basic information, attribute tables were constructed considering landscape and soil properties. Regarding soils, physical fertility properties were considered, since these are the most correlated ones with Pinus ponderosa (pino ponderosa growth, the main species used in afforestation in Patagonia. Those tables were included and analized with a GIS (Geographic Information System to obtain a forest suitability map. The study area shows four forest suitability classes. Suitable: 37ha; moderately suitable: 4.512ha; marginally suitable: 6.072ha; not suitable: 10.444ha. The main limitations of the area are the very steep slopes, height and the areas dominated by rock outcrops and detrital covers. Nothofagus antarctica (ñire shrubs cover part of the suitable areas; because of conservation criteria of these natural communities, these lands were considered not suitable. On the other side, there are more than 4.000 ha of moderately suitable lands, which can be considered for a more detailed study. Transhumant cattle raising is the main land use system in this catchment, which is an ancient culture of the Northern Neuquian

  15. Ignition probability of fine dead surface fuels of native Patagonian forests or Argentina

    Directory of Open Access Journals (Sweden)

    Lucas O. Bianchi

    2014-04-01

    .Keywords: Austrocedrus chilensi; Nothofagus antarctica; wildfire; fire behavior; fuel moisture; fire weather index.

  16. Aggregate and soil organic carbon dynamics in South Chilean Andisols

    Directory of Open Access Journals (Sweden)

    D. Huygens

    2005-01-01

    Full Text Available Extreme sensitivity of soil organic carbon (SOC to climate and land use change warrants further research in different terrestrial ecosystems. The aim of this study was to investigate the link between aggregate and SOC dynamics in a chronosequence of three different land uses of a south Chilean Andisol: a second growth Nothofagus obliqua forest (SGFOR, a grassland (GRASS and a Pinus radiata plantation (PINUS. Total carbon content of the 0-10cm soil layer was higher for GRASS (6.7 kg C m-2 than for PINUS (4.3 kg C m-2, while TC content of SGFOR (5.8 kg C m-2 was not significantly different from either one. High extractable oxalate and pyrophosphate Al concentrations (varying from 20.3-24.4 g kg-1, and 3.9-11.1 g kg-1, respectively were found in all sites. In this study, SOC and aggregate dynamics were studied using size and density fractionation experiments of the SOC, δ13C and total carbon analysis of the different SOC fractions, and C mineralization experiments. The results showed that electrostatic sorption between and among amorphous Al components and clay minerals is mainly responsible for the formation of metal-humus-clay complexes and the stabilization of soil aggregates. The process of ligand exchange between SOC and Al would be of minor importance resulting in the absence of aggregate hierarchy in this soil type. Whole soil C mineralization rate constants were highest for SGFOR and PINUS, followed by GRASS (respectively 0.495, 0.266 and 0.196 g CO2-Cm-2d-1 for the top soil layer. In contrast, incubation experiments of isolated macro organic matter fractions gave opposite results, showing that the recalcitrance of the SOC decreased in another order: PINUS>SGFOR>GRASS. We deduced that electrostatic sorption processes and physical protection of SOC in soil aggregates were the main processes determining SOC stabilization. As a result, high aggregate carbon concentrations, varying from 148 till 48 g kg-1, were encountered for all land use

  17. Emission factors of particulate matter, polycyclic aromatic hydrocarbons, and levoglucosan from wood combustion in south-central Chile.

    Science.gov (United States)

    Jimenez, Jorge; Farias, Oscar; Quiroz, Roberto; Yañez, Jorge

    2017-07-01

    In south-central Chile, wood stoves have been identified as an important source of air pollution in populated areas. Eucalyptus (Eucalyptus globulus), Chilean oak (Nothofagus oblique), and mimosa (Acacia dealbata) were burned in a single-chamber slow-combustion wood stove at a controlled testing facility located at the University of Concepción, Chile. In each experiment, 2.7-3.1 kg of firewood were combusted while continuously monitoring temperature, exhaust gases, burn rate, and collecting particulate matter samples in Teflon filters under isokinetic conditions for polycyclic aromatic hydrocarbon and levoglucosan analyses. Mean particulate matter emission factors were 2.03, 4.06, and 3.84 g/kg dry wood for eucalyptus, oak, and mimosa, respectively. The emission factors were inversely correlated with combustion efficiency. The mean emission factors of the sums of 12 polycyclic aromatic hydrocarbons in particle phases were 1472.5, 2134.0, and 747.5 μg/kg for eucalyptus, oak, and mimosa, respectively. Fluoranthene, pyrene, benzo[a]anthracene, and chrysene were present in the particle phase in higher proportions compared with other polycyclic aromatic hydrocarbons that were analyzed. Mean levoglucosan emission factors were 854.9, 202.3, and 328.0 mg/kg for eucalyptus, oak, and mimosa, respectively. Since the emissions of particulate matter and other pollutants were inversely correlated with combustion efficiency, implementing more efficient technologies would help to reduce air pollutant emissions from wood combustion. Residential wood burning has been identified as a significant source of air pollution in populated areas. Local wood species are combusted for home cooking and heating, which releases several toxic air pollutants, including particulate matter, carbon monoxide, and polycyclic aromatic hydrocarbons. Air pollutant emissions depend on the type of wood and the technology and operational conditions of the wood stove. A better understanding of emissions from

  18. Multiproxy approach revealing climate and cultural changes during the last 26kyrs in south-central Chile

    Science.gov (United States)

    Abarzua, Ana M.; Jarpa, Leonora; Martel, Alejandra; Vega, Rodrigo; Pino, Mario

    2010-05-01

    Multiproxy approach from Purén Lumaco Valley (38°S) describes the paleonvironmental history during the Last Maximum Glacial (LGM) in south-central Chile. Three sediment cores and severals AMS 14C dates were used to perform a complete pollen, diatoms, chironomids, and sedimentological records demonstrating the existence of a large and non profundal paleolake, between 25 and 20kyr BP. Some of these evidence are laminated silty-clay sediments (lacustrine rhythmites), associated with the presence of siderite mineral (FeCO3), besides biological proxies like Fragilaria construens and Stauroforma inermes (planctonic diatoms), and Dicrotendipes sp. and Tanytarsini tribe (littoral chironomids). The pollen ensemble reveals the first glacial refuge of Araucaria araucana forests in the low lands during the LGM. The lake was drained abruptly into a swamp/bog at 12kyr BP and colonized by Myrtaceae wet forest. This evidence suggest the dry/warm climate period of early Holocene in south-central Chile. Later, the sediments indicate variable lacustrine levels, and increase of charcoal particles, associated to current climatic conditions. The pollen spectrum dominated by Myrtaceae and Nothofagus contrasts with a strongly disturb current landscape. Actually, Purén-Lumaco valley constitutes a complex peat-bog system dominated by exotic grasses and forest species (Tritricum aestivum, Pinus radiata and Eucalyptus spp.). Some archaeological antecedents in the area document the human development at ca. 7yrs BP. The greatest archaeological characteristic present in the valley is the kuel, a Mapuche earth accumulation. The presence and extension of almost 300 kuel in the valley reflect the social/economic development, and partly explains why the region was the major resistance area for Spanish colonizer during XVI-XVII centuries. Also the archaeological findings reveal the presence of maize pollen (Zea mays) within their food consumption. The influence of climate and human impact in

  19. Performance of large open-top chambers for long-term field investigations of tree response to elevated carbon dioxide concentration

    International Nuclear Information System (INIS)

    Whitehead, D.; Hogan, K.P.; Rogers, G.N.D.; Byers, J.N.; Hunt, J.E.; McSeveny, T.M.; Hollinger, D.Y.; Dungan, R.J.; Earl, W.B.; Bourke, M.P.

    1995-01-01

    In preparation for an investigation of the effects of elevated carbondioxide (CO 2 ) concentration on the two tree species Pinus radiata D. Don and Nothofagus fusca (Hook. f. ) Oerst, the environmental conditions inside sixteen open-top chambers, of the design described by Heagle et al. (1989), were measured and compared with those outside. During a period in late summer, both air temperature and air saturation deficit were greater inside the chambers, with mean increases of 0.3 degreesC and 0.1 kPa, respectively. The increases were closely related to solar irradiance, reaching maximum differences for temperature and air saturation deficit of 4.3 degrees C and 0.8 kPa, respectively, when solar irradiance was greater than 1600 mu mol m -2 s -1 . The mean (± standard deviation) CO 2 concentrations for the ambient and elevated treatments were 362 ± 37 and 654 ± 69 mu mol mol -1 , respectively. However, the CO 2 concentration in the elevated treatment decreased as wind speed increased, owing to incursions of ambient air into the chambers. Transmittance of visible solar irradiance (400-700 nm) through the plastic wall material decreased by 7% after 1 year of exposure at the site. In cloudy conditions the mean transmittance of solar irradiance into the chambers was 81% and on clear days this decreased from 80% to 74% with increasing solar zenith angle. The ratio of diffuse to total solar irradiance in the chambers was 13% and 21% greater than that outside for cloudy and clear conditions, respectively. The implications of these differences on water use efficiency for the trees growing inside and outside the chamber are discussed. A cost effective system, built to separate the CO 2 required for the experiment from waste biogas, is described. This project is contributing to the Global Change and Terrestrial Ecosystems (GCTE) Core Research Programme by providing data on the long-term effects of elevated CO 2 concentration on the above and below-ground carbon balance for

  20. Long-term vegetation, climate and ocean dynamics inferred from a 73,500 years old marine sediment core (GeoB2107-3) off southern Brazil

    Science.gov (United States)

    Gu, Fang; Zonneveld, Karin A. F.; Chiessi, Cristiano M.; Arz, Helge W.; Pätzold, Jürgen; Behling, Hermann

    2017-09-01

    Long-term changes in vegetation and climate of southern Brazil, as well as ocean dynamics of the adjacent South Atlantic, were studied by analyses of pollen, spores and organic-walled dinoflagellate cysts (dinocysts) in marine sediment core GeoB2107-3 collected offshore southern Brazil covering the last 73.5 cal kyr BP. The pollen record indicates that grasslands were much more frequent in the landscapes of southern Brazil during the last glacial period if compared to the late Holocene, reflecting relatively colder and/or less humid climatic conditions. Patches of forest occurred in the lowlands and probably also on the exposed continental shelf that was mainly covered by salt marshes. Interestingly, drought-susceptible Araucaria trees were frequent in the highlands (with a similar abundance as during the late Holocene) until 65 cal kyr BP, but were rare during the following glacial period. Atlantic rainforest was present in the northern lowlands of southern Brazil during the recorded last glacial period, but was strongly reduced from 38.5 until 13.0 cal kyr BP. The reduction was probably controlled by colder and/or less humid climatic conditions. Atlantic rainforest expanded to the south since the Lateglacial period, while Araucaria forests advanced in the highlands only during the late Holocene. Dinocysts data indicate that the Brazil Current (BC) with its warm, salty and nutrient-poor waters influenced the study area throughout the investigated period. However, variations in the proportion of dinocyst taxa indicating an eutrophic environment reflect the input of nutrients transported mainly by the Brazilian Coastal Current (BCC) and partly discharged by the Rio Itajaí (the major river closest to the core site). This was strongly related to changes in sea level. A stronger influence of the BCC with nutrient rich waters occurred during Marine Isotope Stage (MIS) 4 and in particular during the late MIS 3 and MIS 2 under low sea level. Evidence of Nothofagus pollen

  1. Tree water storage and its diurnal dynamics related to sap flow and changes in stem volume in old-growth Douglas-fir trees.

    Science.gov (United States)

    Cermák, Jan; Kucera, Jiri; Bauerle, William L; Phillips, Nathan; Hinckley, Thomas M

    2007-02-01

    Diurnal and seasonal tree water storage was studied in three large Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) trees at the Wind River Canopy Crane Research site. Changes in water storage were based on measurements of sap flow and changes in stem volume and tissue water content at different heights in the stem and branches. We measured sap flow by two variants of the heat balance method (with internal heating in stems and external heating in branches), stem volume with electronic dendrometers, and tissue water content gravimetrically. Water storage was calculated from the differences in diurnal courses of sap flow at different heights and their integration. Old-growth Douglas-fir trees contained large amounts of free water: stem sapwood was the most important storage site, followed by stem phloem, branch sapwood, branch phloem and needles. There were significant time shifts (minutes to hours) between sap flow measured at different positions within the transport system (i.e., stem base to shoot tip), suggesting a highly elastic transport system. On selected fine days between late July and early October, when daily transpiration ranged from 150 to 300 liters, the quantity of stored water used daily ranged from 25 to 55 liters, i.e., about 20% of daily total sap flow. The greatest amount of this stored water came from the lower stem; however, proportionally more water was removed from the upper parts of the tree relative to their water storage capacity. In addition to lags in sap flow from one point in the hydrolic pathway to another, the withdrawal and replacement of stored water was reflected in changes in stem volume. When point-to-point lags in sap flow (minutes to hours near the top and stem base, respectively) were considered, there was a strong linear relationship between stem volume changes and transpiration. Volume changes of the whole tree were small (equivalent to 14% of the total daily use of stored water) indicating that most stored water came from

  2. Interactions between leaf nitrogen status and longevity in relation to N cycling in three contrasting European forest canopies

    Science.gov (United States)

    Wang, L.; Ibrom, A.; Korhonen, J. F. J.; Arnoud Frumau, K. F.; Wu, J.; Pihlatie, M.; Schjoerring, J. K.

    2012-07-01

    Seasonal and spatial variations in foliar nitrogen (N) parameters were investigated in three European forests with different tree species, viz. beech (Fagus sylvatica L.), Douglas fir (Pseudotsuga menziesii, Mirb., Franco) and Scots pine (Pinus sylvestris L.) in Denmark, The Netherlands and Finland, respectively. This was done in order to obtain information about functional acclimation, tree internal N conservation and its relevance for both ecosystem internal N cycling and foliar N exchange with the atmosphere. Leaf N pools generally showed much higher seasonal variability in beech trees than in the coniferous canopies. The concentrations of N and chlorophyll in the beech leaves were synchronized with the seasonal course of solar radiation implying close physiological acclimation, which was not observed in the coniferous needles. During phases of intensive N metabolism in the beech leaves, the NH4+ concentration rose considerably. This was compensated for by a strong pH decrease resulting in relatively low Γ values (ratio between tissue NH4+ and H+). The Γ values in the coniferous were even smaller than in beech, indicating low probability of NH3 emissions from the foliage to the atmosphere as an N conserving mechanism. The reduction in foliage N content during senescence was interpreted as N re-translocation from the senescing leaves into the rest of the trees. The N re-translocation efficiency (ηr) ranged from 37 to 70% and decreased with the time necessary for full renewal of the canopy foliage. Comparison with literature data from in total 23 tree species showed a general tendency for ηr to on average be reduced by 8% per year the canopy stays longer, i.e. with each additional year it takes for canopy renewal. The boreal pine site returned the lowest amount of N via foliage litter to the soil, while the temperate Douglas fir stand which had the largest peak canopy N content and the lowestηr returned the highest amount of N to the soil. These results

  3. Freezing tolerance of conifer seeds and germinants.

    Science.gov (United States)

    Hawkins, B J; Guest, H J; Kolotelo, D

    2003-12-01

    Survival after freezing was measured for seeds and germinants of four seedlots each of interior spruce (Picea glauca x engelmannii complex), lodgepole pine (Pinus contorta Dougl. ex Loud.), Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and western red cedar (Thuja plicata Donn ex D. Donn). Effects of eight seed treatments on post-freezing survival of seeds and germinants were tested: dry, imbibed and stratified seed, and seed placed in a growth chamber for 2, 5, 10, 15, 20 or 30 days in a 16-h photoperiod and a 22/17 degrees C thermoperiod. Survival was related to the water content of seeds and germinants, germination rate and seedlot origin. After freezing for 3 h at -196 degrees C, dry seed of most seedlots of interior spruce, Douglas-fir and western red cedar had 84-96% germination, whereas lodgepole pine seedlots had 53-82% germination. Freezing tolerance declined significantly after imbibition in lodgepole pine, Douglas-fir and interior spruce seed (western red cedar was not tested), and mean LT50 of imbibed seed of these species was -30, -24.5 and -20 degrees C, respectively. Freezing tolerance continued to decline to a minimum LT50 of -4 to -7 degrees C after 10 days in a growth chamber for interior spruce, Douglas-fir and lodgepole pine, or after 15 days for western red cedar. Minimum freezing tolerance was reached at the stage of rapid hypocotyl elongation. In all species, a slight increase in freezing tolerance of germinants was observed once cotyledons emerged from the seed coat. The decrease in freezing tolerance during the transition from dry to germinating seed correlated with increases in seed water content. Changes in freezing tolerance between 10 and 30 days in the growth chamber were not correlated with seedling water content. Within a species, seedlots differed significantly in freezing tolerance after 2 or 5 days in the growth chamber. Because all seedlots of interior spruce and lodgepole pine germinated quickly, there was no correlation

  4. Stand-Level Gas-Exchange Responses to Seasonal Drought in Very Young Versus Old Douglas-fir Forests of the Pacific Northwest, USA

    Energy Technology Data Exchange (ETDEWEB)

    Wharton, S; Schroeder, M; Bible, K; Falk, M; Paw U, K T

    2009-02-23

    This study examines how stand age affects ecosystem mass and energy exchange response to seasonal drought in three adjacent Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) forests. The sites include two early seral stands (ES) (0-15 years old) and an old-growth (OG) ({approx} 450-500) forest in the Wind River Experiment Forest, Washington, USA. We use eddy covariance flux measurements of carbon dioxide (F{sub NEE}), latent energy ({lambda}E) and sensible heat (H) to derive evapotranspiration rate (E{sub T}), bowen ratio ({beta}), water use efficiency (WUE), canopy conductance (G{sub c}), the Priestley-Taylor coefficient ({alpha}) and a canopy decoupling factor ({Omega}). The canopy and bulk parameters are examined to see how ecophysiological responses to water stress, including changes in available soil water ({theta}{sub r}) and vapor pressure deficit ({delta}e) differ among the two forest successional-stages. Despite very different rainfall patterns in 2006 and 2007, we observed distinct successional-stage relationships between E{sub T}, {alpha}, and G{sub c} to {delta}e and {theta}{sub r} during both years. The largest stand differences were (1) higher morning G{sub c} (> 10 mm s{sup -1}) at the OG forest coinciding with higher CO{sub 2} uptake (F{sub NEE} = -9 to -6 {micro}mol m{sup -2} s{sup -1}) but a strong negative response in G{sub c} to moderate {delta}e later in the day and a subsequent reduction in E{sub T}, and (2) higher E{sub T} at the ES stands because midday canopy conductance did not decrease until very low water availability levels (<30%) were reached at the end of the summer. Our results suggest that early seral stands are more likely than mature forests to experience declines in production if the summer drought becomes longer or intensifies because water conserving ecophysiological responses were only observed at the very end of the seasonal drought period in the youngest stands.

  5. Interactions between leaf nitrogen status and longevity in relation to N cycling in three contrasting European forest canopies

    Directory of Open Access Journals (Sweden)

    L. Wang

    2013-02-01

    Full Text Available Seasonal and spatial variations in foliar nitrogen (N parameters were investigated in three European forests with different tree species, viz. beech (Fagus sylvatica L., Douglas fir (Pseudotsuga menziesii (Mirb. Franco and Scots pine (Pinus sylvestris L. growing in Denmark, the Netherlands and Finland, respectively. The objectives were to investigate the distribution of N pools within the canopies of the different forests and to relate this distribution to factors and plant strategies controlling leaf development throughout the seasonal course of a vegetation period. Leaf N pools generally showed much higher seasonal and vertical variability in beech than in the coniferous canopies. However, also the two coniferous tree species behaved very differently with respect to peak summer canopy N content and N re-translocation efficiency, showing that generalisations on tree internal vs. ecosystem internal N cycling cannot be made on the basis of the leaf duration alone. During phases of intensive N turnover in spring and autumn, the NH4+ concentration in beech leaves rose considerably, while fully developed green beech leaves had relatively low tissue NH4+, similar to the steadily low levels in Douglas fir and, particularly, in Scots pine. The ratio between bulk foliar concentrations of NH4+ and H+, which is an indicator of the NH3 emission potential, reflected differences in foliage N concentration, with beech having the highest values followed by Douglas fir and Scots pine. Irrespectively of the leaf habit, i.e. deciduous versus evergreen, the majority of the canopy foliage N was retained within the trees. This was accomplished through an effective N re-translocation (beech, higher foliage longevity (fir or both (boreal pine forest. In combination with data from a literature review, a general relationship of decreasing N re

  6. Investigación sobre manejo forestal a largo plazo en Patagonia Sur -Argentina: Lecciones del pasado, desafíos del presente Long-term forest management research in South Patagonia - Argentina: Lessons from the past, challenges from the present

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    GUILLERMO J MARTÍNEZ-PASTUR

    2010-03-01

    ón de tratamientos intermedios, (iii determinar líneas base y definir los impactos de distintos sistemas silvícolas, (iv proponer metodologías de monitoreo de amplio espectro y establecer áreas demostrativas de manejo, y (v proveer áreas y conocimientos para entrenar profesionales en prácticas de manejo forestal y conservación de la biodiversidad. Las parcelas permanentes ya establecidas en los bosques de Nothofagus de Patagonia Sur y las bases de datos obtenidas podrían servir como punto de partida para definir un núcleo regional que pueda participar en el International Long Term Ecological Research para asegurar el uso sustentable de los bosques nativos.Argentina has based its economy in agriculture and cattle production seeing forests as one of the main obstacles for future development. Forest harvesting in South Patagonia has been an activity based on colonization and exploitation of new areas. Harvesting is mainly carried out in old-growth forests without silviculture management after the first cuts. Beyond this mismanagement, scientific research defined the basis to conserve, protect and improve the present forest management for the South Patagonia native forests. The first long-term study permanent plots (1965-1966 monitored only economic and forest structure parameters, and near twenty plots were established in public forested lands of Tierra del Fuego. Most of these plots were destroyed or discontinued due to a lack of land use planning, scarce social interest for long-term researches, absence of commitment of institutions, and few contributions of forest companies. After this, a second group of nine long-term study permanent plots were established in South Patagonia (1993-2004 based in the collaboration between private companies and national research institutions. The objectives included economic as well as ecological parameters. The new plots were established on private lands based on several agreements and joint venture projects between national

  7. Diversidad de musgos en ambientes degradados sujetos a restauración en el Parque Nacional Lago Puelo (Chubut, Argentina Moss diversity in degraded environments under restoring in the Lago Puelo National Park (Chubut, Argentina

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    ADRIANA E ROVERE

    2011-12-01

    Full Text Available La restauración ecológica es una disciplina que intenta recuperar atributos perdidos en un ecosistema (diversidad de especies, estructura y función. El objetivo de este trabajo fue evaluar la diversidad de musgos y sus formas de vida en tres ambientes con diferentes niveles de degradación y los sustratos en los que estos se desarrollan. El área de estudio corresponde a un sector que se está restaurando dentro de la Reserva Nacional Lago Puelo. En ella se encuentran tres ambientes distintos: (1 área remanente de bosque maduro de Nothofagus dombeyi, (2 bosque secundario de Austrocedrus chilensis, y (3 matorral dominado por especies exóticas. Se recorrió cada uno de los ambientes, registrando los sustratos con musgos, formas de vida y géneros. Los resultados evidencian una reducción de los sustratos disponibles y de las especies presentes conforme avanza el grado de alteración, desde el área de bosque maduro de N. dombeyi (9 sustratos: 17 géneros: 7 formas de vida, al sector de bosque secundario de A. chilensis (6 sustratos: 8 géneros: 5 formas de vida, siendo menor en el matorral dominado por especies exóticas (1 sustrato: 4 géneros: 3 formas de vida. Los musgos desempeñan funciones importantes en los ecosistemas, son fundamentales en el balance hídrico, pioneros en suelos inestables controlando la erosión y colonizando sitios alterados, sirven como hábitat y alimento para invertebrados, y también constituyen sitios propicios para la germinación de plantas vasculares. Si bien algunas especies leñosas ven afectada su germinación por la presencia de musgos, estos facilitan la germinación de otras especies arbóreas de los bosques templados. Los resultados podrían ser utilizados en restauración, ya sea recreando los sustratos ausentes o realizando traslado de sustratos con musgos, a fin de favorecer la recuperación de áreas boscosas degradadas considerando la biodiversidad original.Ecological restoration is a discipline

  8. Abiotic alterations caused by forest fragmentation affect tree regeneration: a shade and drought tolerance gradient in the remnants of Coastal Maulino Forest Alteraciones abióticas causadas por la fragmentación del bosque afectan la regeneración arbórea: un gradiente de tolerancia a la sombra y la sequía en los remanentes del Bosque Maulino Costero

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    PABLO C GUERRERO

    2009-01-01

    Full Text Available Plant regeneration is strongly determined by light and soil moisture differences between habitáis; both variables are modified by large-scale forest fragmentation. Several studies have indicated this alteration as the mechanism involved in tropical forest community change. The effects of fragmentation may be much more severe in Mediterranean and deciduous forests, because plant species in these forests show a stress tolerance tradeoff between shade and drought. Our study was performed in the deciduous fragmented Coastal Maulino Forest: Reserva Nacional Los Queules (RNLQ and surrounding small fragments. We hypothesised that Aristotelia chilensis (shade intolerant but drought tolerant should increase its regeneration in small patches as a consequence of the change in habitat suitability (i.e. luminous and drier, while Cryptocarya alba (shade tolerant but drought intolerant should have less regeneration in small fragments. We also expected that Nothofagus glauca and N. obliqua, which have shade and drought tolerances intermedíate between A. chilensis and C. alba, should respond less to forest fragmentation. We used two estimations of plant regeneration: (i seedling and sapling densities via field observations and (ii seed germination and seedling establishment via a field-based experiment. Natural regeneration patterns of C. alba indicated a depressed regeneration within small forest fragments compared to RNLQ, although experimental germination, establishment and recruitment proportions did not vary between habitáis. In contrast, A. chilensis regeneration was favored by forest fragmentation, with increased seedling and sapling densities and germination in small forest fragments. Both N. glauca and N. obliqua were less affected by forest fragmentation in their natural and experimental regeneration. This study highlights the relevance of studying changes in abiotic factors as a consequence of human activities, and considering safe sites (defined

  9. Descomposición de hojarasca de Pinus radiata y tres especies arbóreas nativas Decomposition of leaf litter of Pinus radiata and three native tree species

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    CHRISTOPHER H. LUSK

    2001-09-01

    Full Text Available En el centro-sur de Chile, las últimas décadas han sido testigo de una conversión masiva de bosques, matorrales y tierras agrícolas a plantaciones de árboles exóticos. Aunque se ha estudiado la influencia de dichos cambios sobre el balance hídrico, los posibles efectos sobre otros procesos ecosistémicos han recibido poca atención. En esta breve comunicación se presentan datos de un estudio de la descomposición de hojarasca de Pinus radiata y tres especies arbóreas nativas, llevado a cabo con el fin de explorar los posibles efectos del reemplazo de bosque nativo por plantaciones exóticas sobre el ciclaje de nutrientes. Se incubaron muestras de las cuatro especies en dos ambientes distintos en sitios colindantes: bajo un bosque nativo secundario, y bajo un rodal de P. radiata. Se registró la pérdida de peso seco después de dos meses y seis meses. Las tasas diarias de descomposición fueron mucho mayores durante los primeros dos meses de incubación que durante los cuatro meses subsiguientes. En ambas fechas hubo diferencias significativas entre las especies y entre los sitios: todas las especies presentaron mayores tasas de descomposición bajo P. radiata que bajo el bosque nativo. No hubo evidencia de interacción entre sitio y especie. Después de seis meses, el orden de pérdida de peso seco fue Nothofagus obliqua > P. radiata > Peumus boldus > Cryptocarya alba. La variación interespecífica en la tasa de descomposición presentó más relación con el área foliar específica que con el contenido de nitrógeno en la hojarasca. Dado que la hojarasca de P. radiata se descompuso más lentamente que la de la especie caducifolia N. obliqua, pero más rápidamente que las especies esclerófilas, los efectos de la sustitución o invasión sobre descomposición dependerían de la composición original del bosque nativo en cuestiónRecent decades have seen widespread conversion of native forests, shrublands and farmland in south

  10. Efectos de la variación temporal y los métodos de captura en la eficiencia de un muestreo de coleópteros en la Reserva Natural Loma del Medio, El Bolsón, Río Negro Effects of temporal variation and trapping methods on the efficiency of Coleoptera sampling in Loma del Medio Nature Reserve, El Bolsón, Río Negro

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    Paula Sackmann

    2006-12-01

    Full Text Available En este trabajo se analiza la eficiencia de un muestreo sistemático para una comunidad de coleópteros de bosque subantártico. En particular se evalúa: 1- la conveniencia de repartir el esfuerzo de muestreo a lo largo del tiempo (dentro de una misma temporada de actividad de insectos y entre años, y 2- la eficiencia del uso de dos tipos de trampas diferentes. Se seleccionaron 10 sitios en un bosque de Austrocedrus chilensis (Cupresaceae y Nothofagus dombeyii (Fagaceae en la Reserva Forestal Loma del Medio, El Bolsón, Río Negro. En cada sitio se colocaron nueve trampas de caída que abarcaban una superficie de 100 m² y una trampa Malaise. Se realizaron cuatro muestreos anuales (enero, febrero, marzo y abril durante tres años (2002-2004, y de una semana de duración cada uno. La abundancia de especies fue mayor en enero-febrero que en marzo-abril, la riqueza fue similar y la composición de la comunidad fue marcadamente distinta entre dichos períodos para los tres años. Por otro lado, la riqueza de especies fue similar al considerar uno, dos o tres años de muestreo, y en general la composición de la comunidad no varió entre años para períodos comparables. Sin embargo, la acumulación de especies raras sólo se estabilizó luego de tres años de muestreo. Aunque las trampas Malaise fueron más eficientes (número de especies observadas / individuos capturados que las trampas de caída, los métodos de captura fueron altamente complementarios (25% de especies en común. Para caracterizar esta comunidad en particular, se recomienda distribuir el esfuerzo de muestreo a lo largo de una misma temporada de actividad y aplicar diferentes métodos de muestreos. Con un año de muestreo, bajo las condiciones propuestas anteriormente, se podrá caracterizar la comunidad de forma general, pero hacen falta al menos tres años de muestreo para alcanzar un alto grado de integridad. Se incluye un apéndice con la lista de especies capturadas (N

  11. The influence of production conditions, starting material and deposition environment on charcoal alteration in a tropical biome.

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    Ascough, Philippa; Bird, Michael; Meredith, Will; Large, David; Snape, Colin; Manion, Corinne

    2014-05-01

    Natural and anthropogenic burning events are a key link in the global carbon cycle, substantially influencing atmospheric CO2 levels, and consuming c.8700 teragrams yr-1 of dry biomass [1,2,3]. An important result of this process is charcoal, when lignocellulosic structures in biomass (e.g. wood) are converted to aromatic domains with high chemical stability. Charcoal is therefore not readily re-oxidized to CO2, with estimates of 5-7 ky for the half-life of charcoal carbon in soils [3,4]. Charcoal's high carbon content coupled with high environmental resistance has led to the concept of biochar as a valuable means of global carbon sequestration, capable of carbon offsets comparable to annual anthropogenic fuel emissions [5,6,7]. Charcoal is not, however, an environmentally inert substance, and at least some components of charcoal are susceptible to alteration in depositional environments. Despite the importance of charcoal in global carbon cycling, the mechanisms by which charcoal is altered in the environment remain, as yet, poorly understood. This fact limits our ability to properly incorporate both natural environmental charcoal and biochar into global carbon budgets. This study aimed to improve understanding of charcoal alteration in the environment by examining the influence of production conditions, starting material and deposition environment on the physical and chemical characteristics of charcoal at a field site in the Daintree rainforest. These factors have been identified as critical in determining the dynamics of charcoal in depositional environments [8,9] and climatic conditions at the field site (in Tropical Queensland, Australia) are likely to result in extensive alteration of charcoal. Charcoal from wood (Nothofagus spp.), algae (Enteromorpha spp.), and sugarcane (Saccharum spp.) biomass was produced at temperatures over 300-500°C and exposed to conditions of varying pH and vegetation cover. The effect of these variables on charcoal chemistry

  12. Reconstructing streamflow variation of the Baker River from tree-rings in Northern Patagonia since 1765

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    Lara, Antonio; Bahamondez, Alejandra; González-Reyes, Alvaro; Muñoz, Ariel A.; Cuq, Emilio; Ruiz-Gómez, Carolina

    2015-10-01

    The understanding of the long-term variation of large rivers streamflow with a high economic and social relevance is necessary in order to improve the planning and management of water resources in different regions of the world. The Baker River has the highest mean discharge of those draining both slopes of the Andes South of 20°S and it is among the six rivers with the highest mean streamflow in the Pacific domain of South America (1100 m3 s-1 at its outlet). It drains an international basin of 29,000 km2 shared by Chile and Argentina and has a high ecologic and economic value including conservation, tourism, recreational fishing, and projected hydropower. This study reconstructs the austral summer - early fall (January-April) streamflow for the Baker River from Nothofagus pumilio tree-rings for the period 1765-2004. Summer streamflow represents 45.2% of the annual discharge. The regression model for the period (1961-2004) explains 54% of the variance of the Baker River streamflow (R2adj = 0.54). The most significant temporal pattern in the record is the sustained decline since the 1980s (τ = -0.633, p = 1.0144 ∗ 10-5 for the 1985-2004 period), which is unprecedented since 1765. The Correlation of the Baker streamflow with the November-April observed Southern Annular Mode (SAM) is significant (1961-2004, r = -0.55, p < 0.001). The Baker record is also correlated with the available SAM tree-ring reconstruction based on other species when both series are filtered with a 25-year spline and detrended (1765-2004, r = -0.41, p < 0.01), emphasizing SAM as the main climatic forcing of the Baker streamflow. Three of the five summers with the highest streamflow in the entire reconstructed record occurred after the 1950s (1977, 1958 and 1959). The causes of this high streamflow events are not yet clear and cannot be associated with the reported recent increase in the frequency of glacial-lake outburst floods (GLOFs). The decreasing trend in the observed and reconstructed

  13. Transpiration and water use efficiency in native chilean and exotic species, a usefull tool for catchment management?

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    Hervé-Fernández, P.; Oyarzun, C. E.

    2012-04-01

    Land-use and forest cover change play important roles in socio-economic processes and have been linked with water supply and other ecosystem services in various regions of the world. Water yield from watersheds is a major ecosystem service for human activities but has been altered by landscape management superimposed on climatic variability and change. Sustaining ecosystem services important to humans, while providing a dependable water supply for agriculture and urban needs is a major challenge faced by managers of human-dominated or increased antropical effect over watersheds. Since water is mostly consumed by vegetation (i.e: transpiration), which strongly depends on trees physiological characteristics (i.e: foliar area, transpiration capacity) are very important. The quantity of water consumed by plantations is influenced mainly by forest characteristics (species physiology, age and management), catchment water retention capacity and meteorological characteristics. Eventhough in Chile, the forest sector accounts for 3.6% of the gross domestic product (GDP) and 12.5% of total exports (INFOR, 2003), afforestation with fast growing exotic species has ended up being socially and politically questionable because of the supposed impact on the environment and water resources. We present data of trees transpiration and water use efficiency from three headwater catchments: (a) second growth native evergreen forest (Aetoxicon punctatum, Drimys winterii, Gevuina avellana, Laureliopsis philippiana); (b) Eucalyptus globulus plantation, and (c) a mixed native deciduous (Nothofagus obliqua and some evergreen species) forest and Eucalyptus globulus and Acacia melanoxylon plantation located at the Coastal Mountain Range in southern Chile (40°S). Annual transpiration rates ranged from 1.24 ± 0.41 mol•m-2•s-1 (0.022 ± 0.009 L•m-2•s-1) for E. globulus, while the lowest observed was for L. philippiana 0.44 ± 0.31 mol•m-2•s-1 (0.008 ± 0.006 L•m-2•s-1). However

  14. Prioridades de conservación aplicando información filogenética y endemicidad: un ejemplo basado en Carabidae (Coleoptera de América del Sur austral Conservation priorities using phylogenetic information and endemicity: an example based on Carabid beetles from Southern South America

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    Sergio Roig-Juñent

    2004-12-01

    species, 17 areas of endemism were defined. Gamma diversity, percentage of endemism, phylogenetic value, and complementarity, were estimated for each area of endemism, except for the Juan Fernández islands because no information of phylogenetic value was available for this area. Four phylogenetic values of taxonomic weight were calculated, using standardization and endemicity. Results show that standardization of phylogenetic value produce data bias when cladograms differ in size. Complementarity between areas appears as a useful secondary tool. Nevertheless, the results show that complementarity must be used in conjunction with specific diversity and endemicity, to determine the importance of areas. Comparisons of results obtained using W, We, and strict and modified complementarity analyses showed that phylogenetic value with endemicity (We can be applied as a unique value to determine the importance of each area. Using We, the six first areas selected, accumulated 72 % of phylogenetic value, and 74 % of gamma diversity of the southern South American carabids. None of the other used parameters accumulated 70 % of species before the seventh area is added. The six selected areas are the Valdivian rain forest, pampean mountains, Coquimbo, western Patagonia, central Chile, and Araucanian. It is worth to noting that pampean mountains and western Patagonia are grassland habitats, Coquimbo and central Chile are arid and semiarid habitats, and only the Valdivian rain forests and Araucanian are forests with Nothofagus trees

  15. Contact resistance problems applying ERT on low bulk density forested stony soils. Is there a solution?

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    Deraedt, Deborah; Touzé, Camille; Robert, Tanguy; Colinet, Gilles; Degré, Aurore; Garré, Sarah

    2015-04-01

    Electrical resistivity tomography (ERT) has often been put forward as a promising tool to quantify soil water and solute fluxes in a non-invasive way. In our experiment, we wanted to determine preferential flow processes along a forested hillslope using a saline tracer with ERT. The experiment was conducted in the Houille watershed, subcatchment of the Meuse located in the North of Belgian Ardennes (50° 1'52.6'N, 4° 53'22.5'E). The climate is continental but the soil under spruce (Picea abies (L.) Karst.) and Douglas fire stand (Pseudotsuga menziesii (Mirb.) Franco) remains quite dry (19% WVC in average) during the whole year. The soil is Cambisol and the parent rock is Devonian schist covered with variable thickness of silty loam soil. The soil density ranges from 1.13 to 1.87 g/cm3 on average. The stone content varies from 20 to 89% and the soil depth fluctuates between 70 and 130 cm. The ERT tests took place on June 1st 2012, April 1st, 2nd and 3rd 2014 and May 12th 2014. We used the Terrameter LS 12 channels (ABEM, Sweden) in 2012 test and the DAS-1 (Multi-Phase Technologies, United States) in 2014. Different electrode configurations and arrays were adopted for different dates (transect and grid arrays and Wenner - Schlumberger, Wenner alpha and dipole-dipole configurations). During all tests, we systematically faced technical problems, mainly related to bad electrode contact. The recorded data show values of contact resistance above 14873 Ω (our target value would be below 3000 Ω). Subsequently, we tried to improve the contact by predrilling the soil and pouring water in the electrode holes. The contact resistance improved to 14040 Ω as minimum. The same procedure with liquid mud was then tested to prevent quick percolation of the water from the electrode location. As a result, the lower contact resistance dropped to 11745 Ω. Finally, we applied about 25 litre of saline solution (CaCl2, 0.75g/L) homogeneously on the electrode grid. The minimum value of

  16. Structural and compositional controls on transpiration in 40- and 450-year-old riparian forests in western Oregon, USA.

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    Moore, Georgianne W; Bond, Barbara J; Jones, Julia A; Phillips, Nathan; Meinzer, Federick C

    2004-05-01

    Large areas of forests in the Pacific Northwest are being transformed to younger forests, yet little is known about the impact this may have on hydrological cycles. Previous work suggests that old trees use less water per unit leaf area or sapwood area than young mature trees of the same species in similar environments. Do old forests, therefore, use less water than young mature forests in similar environments, or are there other structural or compositional components in the forests that compensate for tree-level differences? We investigated the impacts of tree age, species composition and sapwood basal area on stand-level transpiration in adjacent watersheds at the H.J. Andrews Forest in the western Cascades of Oregon, one containing a young, mature (about 40 years since disturbance) conifer forest and the other an old growth (about 450 years since disturbance) forest. Sap flow measurements were used to evaluate the degree to which differences in age and species composition affect water use. Stand sapwood basal area was evaluated based on a vegetation survey for species, basal area and sapwood basal area in the riparian area of two watersheds. A simple scaling exercise derived from estimated differences in water use as a result of differences in age, species composition and stand sapwood area was used to estimate transpiration from late June through October within the entire riparian area of these watersheds. Transpiration was higher in the young stand because of greater sap flux density (sap flow per unit sapwood area) by age class and species, and greater total stand sapwood area. During the measurement period, mean daily sap flux density was 2.30 times higher in young compared with old Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees. Sap flux density was 1.41 times higher in young red alder (Alnus rubra Bong.) compared with young P. menziesii trees, and was 1.45 times higher in old P. menziesii compared with old western hemlock (Tsuga heterophylla (Raf