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Sample records for hickory trees native

  1. Application of Native Tree Species to Urban Forest

    Institute of Scientific and Technical Information of China (English)

    ZHOUZaohong; GUOMeifeng; WUGuoxun

    2004-01-01

    Native trees play important roles in urban forestry, such as a deep cultural background, a strong ecological adaptability, a high performance-cost ratio and a convenient management. But now there are some difficulties in native trees' utilization and popularization due to few study on landscape plant. In order to seek an abnormal and artificial landscaping and to produce an effective result as soon as possible, native and foreign plants can be properly used as an available resource by improving their technological level and emphasizing natural balance. Then Chinese classic culture and green economics can be combined with beautiful forestry by implementing urban sustainable development.

  2. Seed rain under native and non-native tree species in the Cabo Rojo National Wildlife Refuge, Puerto Rico

    OpenAIRE

    2014-01-01

    Seed dispersal is a fundamental process in plant ecology and is of critical importance for the restoration of tropical communities. The lands of the Cabo Rojo National Wildlife Refuge (CRNWR), formerly under agriculture, were abandoned in the 1970s and colonized mainly by non-native tree species of degraded pastures. Here we described the seed rain under the most common native and non-native trees in the refuge in an attempt to determine if focal tree geographic origin (native versus non-nati...

  3. Multiple Ceratocystis smalleyi infections associated with reduced stem water transport in bitternut hickory.

    Science.gov (United States)

    Park, J-H; Juzwik, J; Cavender-Bares, J

    2013-06-01

    Hundreds of cankers caused by Ceratocystis smalleyi are associated with hickory bark beetle-attacked bitternut hickory exhibiting rapid crown decline in the north-central and northeastern United States. Discolored sapwood colonized by the fungus commonly underlies the cankers. Field studies were conducted to test the hypothesis that C. smalleyi infections cause vascular system dysfunction in infected trees. Fifty C. smalleyi inoculations made at 1.8 to 3.8 m in height on stems of healthy bitternut hickory trees (13 to 28 cm in diameter at 1.4 m in height) resulted in extensive canker formation and sapwood discoloration 12 to 14 months after treatment compared with water-inoculated and noninoculated controls. Sap flow velocity (midday) was significantly lower in the infected trees compared with that in the controls. Sap flow velocity also was inversely correlated with the proportion of bark area with cankered tissues and with tylose abundance in the youngest two growth rings. Tylose formation in current-year vessels associated with C. smalleyi infections is likely responsible for much of the water transport disruption. It is hypothesized that multiple stem infections of C. smalleyi and the resulting xylem dysfunction contribute to crown wilt development in bitternut hickory exhibiting rapid crown decline.

  4. Residential Knowledge of Native Tree Species: A Case Study of Residents in Four Southern Ontario Municipalities

    Science.gov (United States)

    Almas, Andrew D.; Conway, Tenley M.

    2017-01-01

    In the past decade, municipalities across North America have increased investment in their urban forests in an effort to maintain and enhance the numerous benefits provided by them. Some municipalities have now drafted long-term urban forest management plans that emphasize the planting of native trees, to improve ecological integrity, and participation of residents, since the majority of urban trees are typically located on residential property. Yet it is unclear if residents are familiar with native trees or municipalities' urban forest management goals. Through a case study of southern Ontario municipalities, we administered a survey exploring residents' ability to correctly label common tree species as native or non-native, as well as their knowledge of urban forest management plans to test four hypotheses: 1) residents in municipalities with an urban forest management plans will be more knowledgeable about the native status of common street trees; 2) residents who have lived in the area longer will have greater knowledge; 3) knowledge level will be correlated with education level, ethnicity, and income; and 4) residents' knowledge will be related to having planted trees on their property. Our results indicate that residents are better able to identify common native trees than correctly determine which trees are non-native, although knowledge levels are generally low. Knowledge was significantly related to length of residency and tree planting experience, supporting hypotheses 2 and 4. These results highlight the importance of experience and local knowledge acquisition in relation to basic knowledge about urban trees, and also point to the failures of resident outreach within the case study municipalities.

  5. Residential Knowledge of Native Tree Species: A Case Study of Residents in Four Southern Ontario Municipalities.

    Science.gov (United States)

    Almas, Andrew D; Conway, Tenley M

    2017-01-01

    In the past decade, municipalities across North America have increased investment in their urban forests in an effort to maintain and enhance the numerous benefits provided by them. Some municipalities have now drafted long-term urban forest management plans that emphasize the planting of native trees, to improve ecological integrity, and participation of residents, since the majority of urban trees are typically located on residential property. Yet it is unclear if residents are familiar with native trees or municipalities' urban forest management goals. Through a case study of southern Ontario municipalities, we administered a survey exploring residents' ability to correctly label common tree species as native or non-native, as well as their knowledge of urban forest management plans to test four hypotheses: 1) residents in municipalities with an urban forest management plans will be more knowledgeable about the native status of common street trees; 2) residents who have lived in the area longer will have greater knowledge; 3) knowledge level will be correlated with education level, ethnicity, and income; and 4) residents' knowledge will be related to having planted trees on their property. Our results indicate that residents are better able to identify common native trees than correctly determine which trees are non-native, although knowledge levels are generally low. Knowledge was significantly related to length of residency and tree planting experience, supporting hypotheses 2 and 4. These results highlight the importance of experience and local knowledge acquisition in relation to basic knowledge about urban trees, and also point to the failures of resident outreach within the case study municipalities.

  6. Native Americans, regional drought and tree Island evolution in the Florida Everglades

    Science.gov (United States)

    Bernhardt, C.

    2011-01-01

    This study uses palynologic data to determine the effects of regional climate variability and human activity on the formation and development of tree islands during the last ~4000 years. Although prolonged periods of aridity have been invoked as one mechanism for their formation, Native American land use has also been hypothesized as a driver of tree island development. Using pollen assemblages from head and near tail sediments collected on two tree islands and documented archeological data, the relative roles of Native Americans, climate variability, and recent water-management practices in forming and structuring Everglades tree islands are examined. The timing of changes recorded in the pollen record indicates that tree islands developed from sawgrass marshes ~3800 cal. yr BP, prior to human occupation. Major tree island expansion, recorded near tail sediments, occurred ~1000 years after initial tree island formation. Comparison of the timing of pollen assemblages with other proxy records indicates that tree island expansion is related to regional and global aridity correlated with southward migration of the Intertropical Convergence Zone. Local fire associated with droughts may also have influenced tree island expansion. This work suggests that Native American occupation did not significantly influence tree island formation and that the most important factors governing tree island expansion are extreme hydrologic events due to droughts and intense twentieth century water management.

  7. Monitoring oak-hickory forest change during an unprecedented red oak borer outbreak in the Ozark Mountains: 1990 to 2006

    Science.gov (United States)

    Jones, Joshua S.; Tullis, Jason A.; Haavik, Laurel J.; Guldin, James M.; Stephen, Fred M.

    2014-01-01

    Upland oak-hickory forests in Arkansas, Missouri, and Oklahoma experienced oak decline in the late 1990s and early 2000s during an unprecedented outbreak of a native beetle, the red oak borer (ROB), Enaphalodes rufulus (Haldeman). Although remote sensing supports frequent monitoring of continuously changing forests, comparable in situ observations are critical for developing an understanding of past and potential ROB damage in the Ozark Mountains. We categorized forest change using a normalized difference water index (NDWI) applied to multitemporal Landsat TM and ETM+ imagery (1990, 2001, and 2006). Levels of decline or growth were categorized using simple statistical thresholds of change in the NDWI over time. Corresponding decline and growth areas were then observed in situ where tree diameter, age, crown condition, and species composition were measured within variable radius plots. Using a machine learning decision tree classifier, remote sensing-derived decline and growth was characterized in terms of in situ observation. Plots with tree quadratic mean diameter at breast height ≥21.5 cm were categorized remotely as in severe decline. Landsat TM/ETM+-based NDWI derivatives reveal forest decline and regrowth in post-ROB outbreak surveys. Historical and future Landsat-based canopy change detection should be incorporated with existing landscape-based prediction of ROB hazard.

  8. Invasive plant suppresses the growth of native tree seedlings by disrupting belowground mutualisms.

    Directory of Open Access Journals (Sweden)

    Kristina A Stinson

    2006-05-01

    Full Text Available The impact of exotic species on native organisms is widely acknowledged, but poorly understood. Very few studies have empirically investigated how invading plants may alter delicate ecological interactions among resident species in the invaded range. We present novel evidence that antifungal phytochemistry of the invasive plant, Alliaria petiolata, a European invader of North American forests, suppresses native plant growth by disrupting mutualistic associations between native canopy tree seedlings and belowground arbuscular mycorrhizal fungi. Our results elucidate an indirect mechanism by which invasive plants can impact native flora, and may help explain how this plant successfully invades relatively undisturbed forest habitat.

  9. Complementarity of native and introduced tree spe- cies: exploring ...

    African Journals Online (AJOL)

    III. Missouri Botanical Garden, Madagascar Research & Conservation Program, BP 3391, .... sify the different tree species according to the criteria of their choice. ..... Socio-Economique selon le Genre. Rome. Available at .

  10. Phylogenetically diverse AM fungi from Ecuador strongly improve seedling growth of native potential crop trees.

    Science.gov (United States)

    Schüßler, Arthur; Krüger, Claudia; Urgiles, Narcisa

    2016-04-01

    In many deforested regions of the tropics, afforestation with native tree species could valorize a growing reservoir of degraded, previously overused and abandoned land. The inoculation of tropical tree seedlings with arbuscular mycorrhizal fungi (AM fungi) can improve tree growth and viability, but efficiency may depend on plant and AM fungal genotype. To study such effects, seven phylogenetically diverse AM fungi, native to Ecuador, from seven genera and a non-native AM fungus (Rhizophagus irregularis DAOM197198) were used to inoculate the tropical potential crop tree (PCT) species Handroanthus chrysanthus (synonym Tabebuia chrysantha), Cedrela montana, and Heliocarpus americanus. Twenty-four plant-fungus combinations were studied in five different fertilization and AMF inoculation treatments. Numerous plant growth parameters and mycorrhizal root colonization were assessed. The inoculation with any of the tested AM fungi improved seedling growth significantly and in most cases reduced plant mortality. Plants produced up to threefold higher biomass, when compared to the standard nursery practice. AM fungal inoculation alone or in combination with low fertilization both outperformed full fertilization in terms of plant growth promotion. Interestingly, root colonization levels for individual fungi strongly depended on the host tree species, but surprisingly the colonization strength did not correlate with plant growth promotion. The combination of AM fungal inoculation with a low dosage of slow release fertilizer improved PCT seedling performance strongest, but also AM fungal treatments without any fertilization were highly efficient. The AM fungi tested are promising candidates to improve management practices in tropical tree seedling production.

  11. Comparison of leaf decomposition and macroinvertebrate colonization between exotic and native trees in a freshwater ecosystem

    NARCIS (Netherlands)

    Alonso, A.; Gonzalez-Munoz, N.; Castro-Diez, P.

    2010-01-01

    One of the most important sources of energy in aquatic ecosystems is the allochthonous input of detritus. Replacement of native tree species by exotic ones affects the quality of detritus entering freshwater ecosystems. This replacement can alter nutrient cycles and community structure in aquatic ec

  12. Comparison of leaf decomposition and macroinvertebrate colonization between exotic and native trees in a freshwater ecosystem

    NARCIS (Netherlands)

    Alonso, A.; Gonzalez-Munoz, N.; Castro-Diez, P.

    2010-01-01

    One of the most important sources of energy in aquatic ecosystems is the allochthonous input of detritus. Replacement of native tree species by exotic ones affects the quality of detritus entering freshwater ecosystems. This replacement can alter nutrient cycles and community structure in aquatic

  13. A MULTIVARIATE APPROACH TO ANALYSE NATIVE FOREST TREE SPECIE SEEDS

    Directory of Open Access Journals (Sweden)

    Alessandro Dal Col Lúcio

    2006-03-01

    Full Text Available This work grouped, by species, the most similar seed tree, using the variables observed in exotic forest species of theBrazilian flora of seeds collected in the Forest Research and Soil Conservation Center of Santa Maria, Rio Grande do Sul, analyzedfrom January, 1997, to march, 2003. For the cluster analysis, all the species that possessed four or more analyses per lot wereanalyzed by the hierarchical Clustering method, of the standardized Euclidian medium distance, being also a principal componentanalysis technique for reducing the number of variables. The species Callistemon speciosus, Cassia fistula, Eucalyptus grandis,Eucalyptus robusta, Eucalyptus saligna, Eucalyptus tereticornis, Delonix regia, Jacaranda mimosaefolia e Pinus elliottii presentedmore than four analyses per lot, in which the third and fourth main components explained 80% of the total variation. The clusteranalysis was efficient in the separation of the groups of all tested species, as well as the method of the main components.

  14. The Argentine ant persists through unfavorable winters via a mutualism facilitated by a native tree.

    Science.gov (United States)

    Brightwell, Robert J; Silverman, Jules

    2011-10-01

    Mutualisms and facilitations can fundamentally change the relationship between an organism's realized and fundamental niche. Invasive species may prove particularly suitable models for investigating this relationship as many are dependent on finding new partners for successful establishment. We conducted field-based experiments testing whether a native tree facilitates the successful survival of the invasive Argentine ant, Linepithema humile (Mayr), through unfavorable winter conditions in the southeastern United States. We found Argentine ant nests aggregated around the native loblolly pine, Pinus taeda L., during the winter months. The bark of this tree absorbed enough radiant solar energy to reach temperatures suitable for Argentine ant foraging even when ambient temperatures should have curtailed all foraging. Conversely, foraging ceased when the trunk was shaded. The sun-warmed bark of this tree gave the Argentine ant access to a stable honeydew resource. Argentine ants were not found on or near deciduous trees even though bark temperatures were warm enough to permit Argentine ant foraging on cold winter days. Augmenting deciduous trees with sucrose water through the winter months lead to Argentine ant nests remaining at their base and Argentine ants foraging on the tree. The Argentine ant requires both foraging opportunity and a reliable winter food source to survive through unfavorable winter conditions in the southeastern United States. The loblolly pine provided both of these requirements extending the realized niche of Argentine ants beyond its fundamental niche.

  15. Non-Native Ambrosia Beetles as Opportunistic Exploiters of Living but Weakened Trees

    Science.gov (United States)

    Ranger, Christopher M.; Schultz, Peter B.; Frank, Steven D.; Chong, Juang H.; Reding, Michael E.

    2015-01-01

    Exotic Xylosandrus spp. ambrosia beetles established in non-native habitats have been associated with sudden and extensive attacks on a diverse range of living trees, but factors driving their shift from dying/dead hosts to living and healthy ones are not well understood. We sought to characterize the role of host physiological condition on preference and colonization by two invaders, Xylosandrus germanus and Xylosandrus crassiusculus. When given free-choice under field conditions among flooded and non-flooded deciduous tree species of varying intolerance to flooding, beetles attacked flood-intolerant tree species over more tolerant species within 3 days of initiating flood stress. In particular, flood-intolerant flowering dogwood (Cornus florida) sustained more attacks than flood-tolerant species, including silver maple (Acer saccharinum) and swamp white oak (Quercus bicolor). Ethanol, a key host-derived attractant, was detected at higher concentrations 3 days after initiating flooding within stems of flood intolerant species compared to tolerant and non-flooded species. A positive correlation was also detected between ethanol concentrations in stem tissue and cumulative ambrosia beetle attacks. When adult X. germanus and X. crassiusculus were confined with no-choice to stems of flood-stressed and non-flooded C. florida, more ejected sawdust resulting from tunneling activity was associated with the flood-stressed trees. Furthermore, living foundresses, eggs, larvae, and pupae were only detected within galleries created in stems of flood-stressed trees. Despite a capability to attack diverse tree genera, X. germanus and X. crassiusculus efficiently distinguished among varying host qualities and preferentially targeted trees based on their intolerance of flood stress. Non-flooded trees were not preferred or successfully colonized. This study demonstrates the host-selection strategy exhibited by X. germanus and X. crassiusculus in non-native habitats involves

  16. Non-Native Ambrosia Beetles as Opportunistic Exploiters of Living but Weakened Trees.

    Science.gov (United States)

    Ranger, Christopher M; Schultz, Peter B; Frank, Steven D; Chong, Juang H; Reding, Michael E

    2015-01-01

    Exotic Xylosandrus spp. ambrosia beetles established in non-native habitats have been associated with sudden and extensive attacks on a diverse range of living trees, but factors driving their shift from dying/dead hosts to living and healthy ones are not well understood. We sought to characterize the role of host physiological condition on preference and colonization by two invaders, Xylosandrus germanus and Xylosandrus crassiusculus. When given free-choice under field conditions among flooded and non-flooded deciduous tree species of varying intolerance to flooding, beetles attacked flood-intolerant tree species over more tolerant species within 3 days of initiating flood stress. In particular, flood-intolerant flowering dogwood (Cornus florida) sustained more attacks than flood-tolerant species, including silver maple (Acer saccharinum) and swamp white oak (Quercus bicolor). Ethanol, a key host-derived attractant, was detected at higher concentrations 3 days after initiating flooding within stems of flood intolerant species compared to tolerant and non-flooded species. A positive correlation was also detected between ethanol concentrations in stem tissue and cumulative ambrosia beetle attacks. When adult X. germanus and X. crassiusculus were confined with no-choice to stems of flood-stressed and non-flooded C. florida, more ejected sawdust resulting from tunneling activity was associated with the flood-stressed trees. Furthermore, living foundresses, eggs, larvae, and pupae were only detected within galleries created in stems of flood-stressed trees. Despite a capability to attack diverse tree genera, X. germanus and X. crassiusculus efficiently distinguished among varying host qualities and preferentially targeted trees based on their intolerance of flood stress. Non-flooded trees were not preferred or successfully colonized. This study demonstrates the host-selection strategy exhibited by X. germanus and X. crassiusculus in non-native habitats involves

  17. Dry forest restoration and unassisted native tree seedling recruitment at Auwahi, Maui

    Science.gov (United States)

    Medeiros, Arthur C.; von Allmen, E. I.; Chimera, C.G.

    2014-01-01

    Efforts to restore highly degraded but biologically significant forests draw from a limited toolbox. With less than 10% of their former distribution remaining, Hawaiian dry forests, though critically endangered, remain important biological and cultural refugia. At restoration onset (1997), vegetation of restoration and control areas of degraded Auwahi dry forest, Maui Island, was similar, dominated by nonnative graminoids (restoration 78.3%; control 75.4%), especially Cenchrus (Pennisetum) clandestinus. In 2012, unrestored control area vegetation was basically unchanged. In contrast, in the restoration area in 2012, native shrub cover increased from 3.1% to 81.9%, and cover of nonnative graminoids declined from 75.4% to 3.3%. In 2012, nonplanted seedlings of 14 of 22 native tree species and six of seven native shrub species were observed in restoration plots; the majority (99%) were five native (Dodonaea viscosa, Coprosma foliosa, Osteomeles anthyllidifolia, Chamaesyce celastoides, Nestegis sandwicensis) and one nonnative species (Bocconia frutescens). By 2012, stem counts of native woody plants had increased from 12.4 to 135.0/100 m2, and native species diversity increased from 2.4 to 6.6/100 m2. By 2012, seven rare dry forest tree species, Charpentiera obovata, Nothocestrum latifolium, Ochrosia haleakalae, Pleomele auwahiensis, Santalum ellipticum, S. haleakalae, and Streblus pendulinus, had established seedlings and/or saplings within the restoration site, especially notable because natural reproduction is largely lacking elsewhere. Without development and implementation of appropriate management strategies, remaining Hawaiian dry forest will likely disappear within the next century. Multicomponent restoration incorporating ungulate exclusion, weed control, and outplanting as described here offers one strategy to conserve and restore tracts of high-value but degraded forests.

  18. Propagation of Native Tree Species to Restore Subtropical Evergreen Broad-Leaved Forests in SW China

    Directory of Open Access Journals (Sweden)

    Yang Lu

    2016-01-01

    Full Text Available Subtropical evergreen broad-leaved forest (EBLF is a widespread vegetation type throughout East Asia that has suffered extensive deforestation and fragmentation. Selection and successful propagation of native tree species are important for improving ecological restoration of these forests. We carried out a series of experiments to study the propagation requirements of indigenous subtropical tree species in Southwest China. Seeds of 21 tree species collected from the natural forest were materials for the experiment. This paper examines the seed germination and seedling growth performance of these species in a nursery environment. Germination percentages ranged from 41% to 96% and were ≥50% for 19 species. The median length of germination time (MLG ranged from 24 days for Padus wilsonii to 144 days for Ilex polyneura. Fifteen species can reach the transplant size (≥15 cm in height within 12 months of seed collection. Nursery-grown seedlings for each species were planted in degraded site. Two years after planting, the seedling survival rate was >50% in 18 species and >80% in 12 species. Based on these results, 17 species were recommended as appropriate species for nursery production in forest restoration projects. Our study contributes additional knowledge regarding the propagation techniques for various native subtropical tree species in nurseries for forest restoration.

  19. Predicting climate change impacts on native and invasive tree species using radial growth and twenty-first century climate scenarios

    NARCIS (Netherlands)

    González-Muñoz, N.; Linares, J.C.; Castro-Díez, P.; Sass-Klaassen, U.G.W.

    2014-01-01

    The climatic conditions predicted for the twenty-first century may aggravate the extent and impacts of plant invasions, by favouring those invaders more adapted to altered conditions or by hampering the native flora. We aim to predict the fate of native and invasive tree species in the oak forests o

  20. Predicting climate change impacts on native and invasive tree species using radial growth and twenty-first century climate scenarios

    NARCIS (Netherlands)

    González-Muñoz, N.; Linares, J.C.; Castro-Díez, P.; Sass-Klaassen, U.G.W.

    2014-01-01

    The climatic conditions predicted for the twenty-first century may aggravate the extent and impacts of plant invasions, by favouring those invaders more adapted to altered conditions or by hampering the native flora. We aim to predict the fate of native and invasive tree species in the oak forests

  1. Potential hosts of Prostephanus truncatus (Coleoptera: Bostrichidae) among native and agroforestry trees in Kenya.

    Science.gov (United States)

    Nangáyo, F L O; Hill, M G; Wright, D J

    2002-12-01

    This study was carried out to establish the extent to which an invasive stored products pest, Prostephanus truncatus Horn exploits wood as a feeding and breeding resource in Kenya. Twenty seven out of 84 native and agroforestry trees and shrubs supported the breeding of P. truncatus under laboratory conditions. Adult survival (<1% to 18%) for 8 weeks was recorded on 51 tree species that did not support breeding. The breeding success of this beetle varied widely between host tree species and showed no obvious trends based on tree systematics or wood hardness. Studies of P. truncatus survival on two host tree species found that the greatest increase in the P. truncatus population occurred on stem sapwood, whilst the smallest population increase was on twigs. Breeding also varied greatly from season to season; studies on ten selected host species showed that reproduction was often greatest in wood samples collected and tested during the dry season in September. The implications of these findings for the management of P. truncatus infestations in farm stored maize are discussed.

  2. Ghosts of Cultivation Past - Native American Dispersal Legacy Persists in Tree Distribution

    Science.gov (United States)

    Warren, Robert J.

    2016-01-01

    A long-term assumption in ecology is that species distributions correspond with their niche requirements, but evidence that species can persist in unsuitable habitat for centuries undermines the link between species and habitat. Moreover, species may be more dependent on mutualist partners than specific habitats. Most evidence connecting indigenous cultures with plant dispersal is anecdotal, but historical records suggest that Native Americans transported and cultivated many species, including Gleditsia triacanthos ("Honey locust"). Gleditsia triacanthos was an important medicinal/culinary (e.g., sugar), cultural (e.g., game sticks) and spiritual tree for the Cherokee (southeastern U.S. Native Americans). This study tests the hypothesis that a Cherokee cultivation legacy drives current regional G. triacanthos distribution patterns. Gleditsia triacanthos occurs in rocky uplands and xeric fields, but inexplicably also occurs in mesic riverine corridors and floodplains where Cherokee once settled and farmed. I combined field experiments and surveys in the Southern Appalachian Mountain region (U.S.) to investigate G. triacanthos recruitment requirements and distribution patterns to determine whether there is a quantifiable G. triacanthos association with former Cherokee settlements. Moreover, I also investigated alternate dispersal mechanisms, such as stream transport and domestic cattle. The results indicate that a centuries-old legacy of Native American cultivation remains intact as G. triacanthos' current southern Appalachian distribution appears better explained Cherokee settlement patterns than habitat. The data indicate that the tree is severely dispersal limited in the region, only moving appreciable distances from former Cherokee settlements where cattle grazing is prevalent. Human land use legacy may play a long-term role in shaping species distributions, and pre-European settlement activity appears underrated as a factor influencing modern tree species

  3. Ghosts of Cultivation Past - Native American Dispersal Legacy Persists in Tree Distribution.

    Science.gov (United States)

    Warren, Robert J

    2016-01-01

    A long-term assumption in ecology is that species distributions correspond with their niche requirements, but evidence that species can persist in unsuitable habitat for centuries undermines the link between species and habitat. Moreover, species may be more dependent on mutualist partners than specific habitats. Most evidence connecting indigenous cultures with plant dispersal is anecdotal, but historical records suggest that Native Americans transported and cultivated many species, including Gleditsia triacanthos ("Honey locust"). Gleditsia triacanthos was an important medicinal/culinary (e.g., sugar), cultural (e.g., game sticks) and spiritual tree for the Cherokee (southeastern U.S. Native Americans). This study tests the hypothesis that a Cherokee cultivation legacy drives current regional G. triacanthos distribution patterns. Gleditsia triacanthos occurs in rocky uplands and xeric fields, but inexplicably also occurs in mesic riverine corridors and floodplains where Cherokee once settled and farmed. I combined field experiments and surveys in the Southern Appalachian Mountain region (U.S.) to investigate G. triacanthos recruitment requirements and distribution patterns to determine whether there is a quantifiable G. triacanthos association with former Cherokee settlements. Moreover, I also investigated alternate dispersal mechanisms, such as stream transport and domestic cattle. The results indicate that a centuries-old legacy of Native American cultivation remains intact as G. triacanthos' current southern Appalachian distribution appears better explained Cherokee settlement patterns than habitat. The data indicate that the tree is severely dispersal limited in the region, only moving appreciable distances from former Cherokee settlements where cattle grazing is prevalent. Human land use legacy may play a long-term role in shaping species distributions, and pre-European settlement activity appears underrated as a factor influencing modern tree species

  4. Ghosts of Cultivation Past - Native American Dispersal Legacy Persists in Tree Distribution.

    Directory of Open Access Journals (Sweden)

    Robert J Warren

    Full Text Available A long-term assumption in ecology is that species distributions correspond with their niche requirements, but evidence that species can persist in unsuitable habitat for centuries undermines the link between species and habitat. Moreover, species may be more dependent on mutualist partners than specific habitats. Most evidence connecting indigenous cultures with plant dispersal is anecdotal, but historical records suggest that Native Americans transported and cultivated many species, including Gleditsia triacanthos ("Honey locust". Gleditsia triacanthos was an important medicinal/culinary (e.g., sugar, cultural (e.g., game sticks and spiritual tree for the Cherokee (southeastern U.S. Native Americans. This study tests the hypothesis that a Cherokee cultivation legacy drives current regional G. triacanthos distribution patterns. Gleditsia triacanthos occurs in rocky uplands and xeric fields, but inexplicably also occurs in mesic riverine corridors and floodplains where Cherokee once settled and farmed. I combined field experiments and surveys in the Southern Appalachian Mountain region (U.S. to investigate G. triacanthos recruitment requirements and distribution patterns to determine whether there is a quantifiable G. triacanthos association with former Cherokee settlements. Moreover, I also investigated alternate dispersal mechanisms, such as stream transport and domestic cattle. The results indicate that a centuries-old legacy of Native American cultivation remains intact as G. triacanthos' current southern Appalachian distribution appears better explained Cherokee settlement patterns than habitat. The data indicate that the tree is severely dispersal limited in the region, only moving appreciable distances from former Cherokee settlements where cattle grazing is prevalent. Human land use legacy may play a long-term role in shaping species distributions, and pre-European settlement activity appears underrated as a factor influencing modern tree

  5. The Role of Native Tree Species on Leaf Breakdown Dynamics of the Invasive Tree of Heaven ( Ailanthus altissima) in an Urban Stream

    Science.gov (United States)

    Swan, C.; Healey, B.

    2005-05-01

    Anthropogenic disturbance of ecosystem processes is increasingly being explored in urban settings. One profound impact is the striking increase in the distribution of invasive plant species. For example, Tree of Heaven (Ailanthus altissima, TOH), introduced into the U.S. from Asia in 1784, is a successful colonist of recently deforested habitats. As a result, remnant patches in urban ecosystems have become overrun with this tree species, excluding native species via fast growth and allelopathy. While suffering from human-induced degradation, urban streams still support food webs that function to process riparian-derived organic matter (e.g., leaves, wood). The purpose of this study was to (1) estimate leaf litter breakdown of native tree leaves and those of TOH in an urban stream, (2) study the detritivore feeding rate of the same leaf species, and (3) determine if increasing native species richness of leaf litter can alter breakdown of TOH leaves. Field manipulations of leaf pack composition were done in a highly urbanized stream (>30% upstream urban land use) in Baltimore County, Maryland, USA. This was complimented by a series of laboratory feeding experiments employing similar leaf treatments and local shredding invertebrate taxa. Breakdown of TOH alone was extremely rapid, significantly exceeding that of all native tree species employed. Furthermore, mixing TOH with native tree species, red maple and white oak, substantially reduced TOH decay compared to decay of TOH alone. However, supporting laboratory studies showed that TOH was a preferred resource by shredding invertebrates over all native species. Subsequent analysis of the structural integrity of all leaf species revealed that TOH was the least resistant to force, possibly explaining the counterintuitive decrease of TOH decay in mixtures. We interpret this as meaning the stream invertebrates, while preferring to consume TOH, appeared not to influence TOH decay in mixtures with native species. Instead

  6. Is invasion success of Australian trees mediated by their native biogeography, phylogenetic history, or both?

    Science.gov (United States)

    Miller, Joseph T; Hui, Cang; Thornhill, Andrew; Gallien, Laure; Le Roux, Johannes J; Richardson, David M

    2016-12-30

    For a plant species to become invasive it has to progress along the introduction-naturalization-invasion (INI) continuum which reflects the joint direction of niche breadth. Identification of traits that correlate with and drive species invasiveness along the continuum is a major focus of invasion biology. If invasiveness is underlain by heritable traits, and if such traits are phylogenetically conserved, then we would expect non-native species with different introduction status (i.e. position along the INI continuum) to show phylogenetic signal. This study uses two clades that contain a large number of invasive tree species from the genera Acacia and Eucalyptus to test whether geographic distribution and a novel phylogenetic conservation method can predict which species have been introduced, became naturalized, and invasive. Our results suggest that no underlying phylogenetic signal underlie the introduction status for both groups of trees, except for introduced acacias. The more invasive acacia clade contains invasive species that have smoother geographic distributions and are more marginal in the phylogenetic network. The less invasive eucalyptus group contains invasive species that are more clustered geographically, more centrally located in the phylogenetic network and have phylogenetic distances between invasive and non-invasive species that are trending toward the mean pairwise distance. This suggests that highly invasive groups may be identified because they have invasive species with smoother and faster expanding native distributions and are located more to the edges of phylogenetic networks than less invasive groups.

  7. Genetic dissimilarity among jabuticaba trees native to southwestern Paraná, Brazil

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    Moeses Andrigo Danner

    2011-06-01

    Full Text Available Knowledge on the genetic diversity within and between genotype groups is of great importance for breeding programs. The purpose of this study was to estimate the genetic dissimilarity among 36 native jabuticaba trees (Plinia cauliflora from five sites in the southwestern region of Paraná, Brazil. Sixteen fruit traits were analyzed, based on multivariate techniques (canonical variables, Tocher and UPGMA, using Mahalanobis' distance as dissimilarity measure. By the techniques of clustering and graphic dispersion, together with the comparison of means, the genetic diversity among native jabuticaba trees was efficiently identified, indicating a high potential of these genotypes for breeding programs. The traits of greatest importance for dissimilarity were percentage of pulp and of skin, which are easily measured. The clustering structure is related to the collection sites and for breeding programs, genotypes from different sites should be crossed to generate progenies to be tested. Genotypes 'CV5' and 'VT3' should be conserved in genebanks, due to its important agronomic traits.

  8. Soil nematode community under the non-native trees in the Botanic Garden of Petrozavodsk State University

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    Sushchuk Anna

    2016-12-01

    Full Text Available The particularities of soil nematode communities of the rhizosphere of non-native trees were studied in the Botanic Garden of Petrozavodsk State University (Republic of Karelia. Taxonomic diversity, abundance, community structure and ecological indices derived from nematode fauna analysis were used as the evaluation parameters. Nematode fauna included 51 genera, 6 of them were plant parasitic. The dominant eco-trophic group in the nematode community structure of coniferous trees was bacterial feeders; fungal feeders in most cases were observed in the second numbers. The contribution of bacterial feeders was decreased and plant parasites were increased in eco-trophic structure of nematode communities of deciduous trees in compared with coniferous trees. Analysis of ecological indices showed that the state of soil nematode communities reflects complex, structured (stable soil food web in the biocenoses with deciduous trees, and degraded (basal food web – under coniferous trees.

  9. Morphological defects in native Japanese fir trees around the Fukushima Daiichi Nuclear Power Plant.

    Science.gov (United States)

    Watanabe, Yoshito; Ichikawa, San'ei; Kubota, Masahide; Hoshino, Junko; Kubota, Yoshihisa; Maruyama, Kouichi; Fuma, Shoichi; Kawaguchi, Isao; Yoschenko, Vasyl I; Yoshida, Satoshi

    2015-08-28

    After the accident at the Fukushima Daiichi Nuclear Power Plant (F1NPP) in March 2011, much attention has been paid to the biological consequences of the released radionuclides into the surrounding area. We investigated the morphological changes in Japanese fir, a Japanese endemic native conifer, at locations near the F1NPP. Japanese fir populations near the F1NPP showed a significantly increased number of morphological defects, involving deletions of leader shoots of the main axis, compared to a control population far from the F1NPP. The frequency of the defects corresponded to the radioactive contamination levels of the observation sites. A significant increase in deletions of the leader shoots became apparent in those that elongated after the spring of 2012, a year after the accident. These results suggest possibility that the contamination by radionuclides contributed to the morphological defects in Japanese fir trees in the area near the F1NPP.

  10. The introduced tree Prosopis juliflora is a serious threat to native species of the Brazilian Caatinga vegetation.

    Science.gov (United States)

    de Souza Nascimento, Clóvis Eduardo; Tabarelli, Marcelo; da Silva, Carlos Alberto Domingues; Leal, Inara Roberta; de Souza Tavares, Wagner; Serrão, José Eduardo; Zanuncio, José Cola

    2014-05-15

    Despite its economic importance in the rural context, the Prosopis juliflora tree species has already invaded millions of hectares globally (particularly rangelands), threatening native biodiversity and rural sustainability. Here we examine seedling growth (leaf area, stem diameter, plant height) and seedling mortality across five native plant species of the Caatinga vegetation in response to competition with P. juliflora. Two sowing treatments with 10 replications were adopted within a factorial 2 × 5 randomized block design. Treatments consisted of P. juliflora seeds sowed with seeds of Caesalpinia ferrea, Caesalpinia microphylla, Erythrina velutina, Mimosa bimucronata and Mimosa tenuiflora (one single native species per treatment), while seeds of native species sowed without P. juliflora were adopted as controls. Overall, our results suggest that P. juliflora can reduce seedling growth by half and cause increased seedling mortality among woody plant species. Moreover, native species exhibit different levels of susceptibility to competition with P. juliflora, particularly in terms of plant growth. Such a superior competitive ability apparently permits P. juliflora to establish monospecific stands of adult trees, locally displacing native species or limiting their recruitment. The use of less sensitive species, such as C. ferrea and M. tenuiflora, to restore native vegetation before intensive colonization by P. juliflora should be investigated as an effective approach for avoiding its continuous spread across the Caatinga region. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Genetic and environmental influences on leaf phenology and cold hardiness of native and introduced riparian trees

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    Friedman, J.M.; Roelle, J.E.; Cade, B.S.

    2011-01-01

    To explore the roles of plasticity and genetic variation in the response to spatial and temporal climate variation, we established a common garden consisting of paired collections of native and introduced riparian trees sampled along a latitudinal gradient. The garden in Fort Collins, Colorado (latitude 40.6??N), included 681 native plains cottonwood (Populus deltoides subsp. monilifera) and introduced saltcedar (Tamarix ramosissima, T. chinensis and hybrids) collected from 15 sites at 29.2-47.6??N in the central United States. In the common garden both species showed latitudinal variation in fall, but not spring, leaf phenology, suggesting that the latitudinal gradient in fall phenology observed in the field results at least in part from inherited variation in the critical photoperiod, while the latitudinal gradient in spring phenology observed in the field is largely a plastic response to the temperature gradient. Populations from higher latitudes exhibited earlier bud set and leaf senescence. Cold hardiness varied latitudinally in both fall and spring for both species. For cottonwood, cold hardiness began earlier and ended later in northern than in southern populations. For saltcedar northern populations were hardier throughout the cold season than southern populations. Although cottonwood was hardier than saltcedar in midwinter, the reverse was true in late fall and early spring. The latitudinal variation in fall phenology and cold hardiness of saltcedar appears to have developed as a result of multiple introductions of genetically distinct populations, hybridization and natural selection in the 150 years since introduction. ?? 2011 US Government.

  12. Genetic and environmental influences on leaf phenology and cold hardiness of native and introduced riparian trees.

    Science.gov (United States)

    Friedman, Jonathan M; Roelle, James E; Cade, Brian S

    2011-11-01

    To explore the roles of plasticity and genetic variation in the response to spatial and temporal climate variation, we established a common garden consisting of paired collections of native and introduced riparian trees sampled along a latitudinal gradient. The garden in Fort Collins, Colorado (latitude 40.6°N), included 681 native plains cottonwood (Populus deltoides subsp. monilifera) and introduced saltcedar (Tamarix ramosissima, T. chinensis and hybrids) collected from 15 sites at 29.2-47.6°N in the central United States. In the common garden both species showed latitudinal variation in fall, but not spring, leaf phenology, suggesting that the latitudinal gradient in fall phenology observed in the field results at least in part from inherited variation in the critical photoperiod, while the latitudinal gradient in spring phenology observed in the field is largely a plastic response to the temperature gradient. Populations from higher latitudes exhibited earlier bud set and leaf senescence. Cold hardiness varied latitudinally in both fall and spring for both species. For cottonwood, cold hardiness began earlier and ended later in northern than in southern populations. For saltcedar northern populations were hardier throughout the cold season than southern populations. Although cottonwood was hardier than saltcedar in midwinter, the reverse was true in late fall and early spring. The latitudinal variation in fall phenology and cold hardiness of saltcedar appears to have developed as a result of multiple introductions of genetically distinct populations, hybridization and natural selection in the 150 years since introduction.

  13. Potential Germination Success of Exotic and Native Trees Coexisting in Central Spain Riparian Forests

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    Isabel Cabra-Rivas

    2016-01-01

    Full Text Available We compared potential germination success (i.e., percentage of produced seeds that germinate under optimal conditions, the percentage of empty and insect-damaged seeds, germinability (Gmax, and time to germination (Tgerm between the exotics Ailanthus altissima, Robinia pseudoacacia, and Ulmus pumila and two coexisting native trees (Fraxinus angustifolia and Ulmus minor in the riparian forests of Central Spain. Additionally, we tested the effect of seed age, seed bank type (canopy or soil and population on Gmax and Tgerm of A. altissima and R. pseudoacacia, which are seed-banking species. Species ranked by their potential germination success were A. altissima > U. pumila > R. pseudoacacia > U. minor > F. angustifolia. The combination of a high Gmax and negligible seed insect-damage provided A. altissima with a potential germination advantage over the natives, which were the least successful due to an extremely high percentage of empty seeds or a very low Gmax. R. pseudoacacia showed high vulnerability to insect seed predation which might be compensated with the maintenance of persistent seed banks with high Gmax. Gmax and Tgerm were strongly affected by seed age in the seed-banking invaders, but between-seed bank variation of Gmax and Tgerm did not show a consistent pattern across species and populations.

  14. A native plant competitor mediates the impact of above- and belowground damage on an invasive tree.

    Science.gov (United States)

    Carrillo, Juli; Siemann, Evan

    2016-10-01

    Plant competition may mediate the impacts of herbivory on invasive plant species through effects on plant growth and defense. This may predictably depend on whether herbivory occurs above or below ground and on relative plant competitive ability. We simulated the potential impact of above- or belowground damage by biocontrol agents on the growth of a woody invader (Chinese tallow tree, Triadica sebifera) through artificial herbivory, with or without competition with a native grass, little bluestem (Schizachyrium scoparium). We measured two defense responses of Triadica through quantifying constitutive and induced extrafloral nectar production and tolerance of above- and belowground damage (root and shoot biomass regrowth). We examined genetic variation in plant growth and defense across native (China) and invasive (United States) Triadica populations. Without competition, aboveground damage had a greater impact than belowground damage on Triadica performance, whereas with competition and above- and belowground damage impacted Triadica similarly. Whole plant tolerance to damage below ground was negatively associated with tolerance to grass competitors indicating tradeoffs in the ability to tolerate herbivory vs. compete. Competition reduced investment in defensive extrafloral nectar (EFN) production. Aboveground damage inhibited rather than induced EFN production while belowground plant damage did not impact aboveground nectar production. We found some support for the evolution of increased competitive ability hypothesis for invasive plants as United States plants were larger than native China plants and were more plastic in their response to biotic stressors than China plants (they altered their root to shoot ratios dependent on herbivory and competition treatments). Our results indicate that habitat type and the presence of competitors may be a larger determinant of herbivory impact than feeding mode and suggest that integrated pest management strategies including

  15. Establishment Success of Coexisting Native and Exotic Trees Under an Experimental Gradient of Irradiance and Soil Moisture

    Science.gov (United States)

    González-Muñoz, Noelia; Castro-Díez, Pilar; Fierro-Brunnenmeister, Natalia

    2011-10-01

    The exotic trees Ailanthus altissima, Robinia pseudoacacia, Acer negundo and Elaeagnus angustifolia coexist with the native trees Fraxinus angustifolia and Ulmus minor in river banks of central Spain. Similarly, the exotic trees Acacia dealbata and Eucalyptus globulus co-occur with the natives Quercus pyrenaica and Pinus pinaster in Northwest Spain. We aimed to identify the environmental conditions that favour or hamper the establishment success of these species. In spring 2008, seeds of the studied species were sown under an experimental gradient of light (100, 65, 35, 7% of full sunlight) combined with three levels of soil moisture (mean soil water potential = -0.97, -1.52 and -1.77 MPa.). During the first growing season we monitored seed emergence and seedling survival. We found that the effect of light on the establishment success was stronger than the effect of soil moisture. Both exotic and native species of central Spain showed a good performance under high light, A. negundo being the most shade tolerant . Water shortage diminished E. angustifolia and A. altissima success. Among NW Spain species, A. dealbata and P. pinaster were found to be potential competitors for colonizing high-irradiance scenarios, while Q. pyrenaica and E. globulus were more successful under moderate shade. High soil moisture favoured E. globulus but not A. dealbata establishment. These results contribute to understand some of the factors controlling for spatial segregation between coexisting native and exotic tree species, and can help to take decisions orientated to the control and management of these exotic species.

  16. Comparative Proteomic Analysis of the Graft Unions in Hickory (Carya cathayensis Provides Insights into Response Mechanisms to Grafting Process

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    Daoliang Yan

    2017-04-01

    Full Text Available Hickory (Carya cathayensis, a tree with high nutritional and economic value, is widely cultivated in China. Grafting greatly reduces the juvenile phase length and makes the large scale cultivation of hickory possible. To reveal the response mechanisms of this species to grafting, we employed a proteomics-based approach to identify differentially expressed proteins in the graft unions during the grafting process. Our study identified 3723 proteins, of which 2518 were quantified. A total of 710 differentially expressed proteins (DEPs were quantified and these were involved in various molecular functional and biological processes. Among these DEPs, 341 were up-regulated and 369 were down-regulated at 7 days after grafting compared with the control. Four auxin-related proteins were down-regulated, which was in agreement with the transcription levels of their encoding genes. The Kyoto Encyclopedia of Genes and Genomes (KEGG analysis showed that the ‘Flavonoid biosynthesis’ pathway and ‘starch and sucrose metabolism’ were both significantly up-regulated. Interestingly, five flavonoid biosynthesis-related proteins, a flavanone 3-hyfroxylase, a cinnamate 4-hydroxylase, a dihydroflavonol-4-reductase, a chalcone synthase, and a chalcone isomerase, were significantly up-regulated. Further experiments verified a significant increase in the total flavonoid contents in scions, which suggests that graft union formation may activate flavonoid biosynthesis to increase the content of a series of downstream secondary metabolites. This comprehensive analysis provides fundamental information on the candidate proteins and secondary metabolism pathways involved in the grafting process for hickory.

  17. Aboveground biomass, wood volume, nutrient stocks and leaf litter in novel forests compared to native forests and tree plantations in Puerto Rico

    Science.gov (United States)

    A.E. Lugo; O. Abelleira Martínez; J. Fonseca da Silva

    2012-01-01

    The article presents comparative data for aboveground biomass, wood volume, nutirent stocks (N, P, K) and leaf litter in different types of forests in Puerto Rico. The aim of the study is to assess how novel forests of Castilla elastica, Panama Rubber Tree, and Spathodea campanulata, African Tulip Tree, compare with tree plantations and native historical forests (both...

  18. The breeding system and effectiveness of introduced and native pollinators of the endangered tropical tree Goetzea elegans (Solanaceae

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    Santiago-Valentín, Eugenio

    2011-05-01

    Full Text Available The impact of introduced species on native organisms is one of the main conservation concerns around the world. To fully understand the effect of introduced pollinators on native plants, it is important to know the reproductive biology of the focal species, especially its pollination biology. In this study we examined the breeding system of the endangered tree Goetzea elegans (Solanaceae, and compared pollination effectiveness of the two main floral visitors, Coereba flaveola (an avian nectarivore, and Apis mellifera (the introduced European Honeybee. We assessed the breeding system of G. elegans by applying several pollination treatments to flowers of cultivated trees to test fruit set, seed set, and seed viability. We also examined the pollination efficiency of A. mellifera and C. flaveola , and compared all the treatments with positive and negative controls. Our results indicate that the introduced honeybee A. mellifera is as efficient as the native bird C. flaveola in pollinating the flowers of G. elegans. This study also showed that G. elegans requires cross–pollination for fruit and seed set, and to obtain high seed viability rates. Despite the fact that many studies report exotic species as detrimental for native organisms, we document a case where an introduced insect has a beneficial impact on the reproductive biology of an endangered tropical tree.

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

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    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.

  20. Toward a predictive model for water and carbon fluxes of non-native trees in urban habitats

    Science.gov (United States)

    McCarthy, H. R.; Jenerette, G. D.; Pataki, D. E.

    2008-12-01

    There is considerable interest in estimating uptake of water and carbon by urban trees, in order to assess some of the major costs and benefits associated with maintaining or expanding urban tree cover. However, making large-scale estimates of water and carbon fluxes is challenging in urban ecosystems, where community composition and environmental conditions are highly altered and experimental data is sparse. This is particularly true in regions such as southern California, where few trees are native, yet many species can flourish given supplemental irrigation. In such scenarios one practical way to scale water and carbon fluxes may be to identify reliable traits which can be used to predict gas exchange when trees are transplanted to a new environment. To test this approach, leaf level gas exchange measurements were conducted on eight common urban tree species within the Los Angeles basin. The objective was to determine how well gas exchange parameters, including maximum photosynthesis and stomatal conductance, sensitivity of stomatal conductance to vapor pressure deficit (VPD), and water use efficiency (WUE), can be predicted based on the native habitat and climate (temperature and precipitation) of each study species. All of the species studied naturally occur in humid tropical or subtropical climate zones where precipitation varies widely from ~400 - 3000 mm per year. We found Jacaranda (Jacaranda chelonia) and honey locust (Gleditsia triacanthos) to have the highest photosynthesis and reference (at VPD=1 kPa) conductance, and to be most sensitive to VPD. WUE was found to be greatest in Indian laurel fig (Ficus microcarpa), rose gum (Eucalyptus grandis) and Queensland lacebark (Brachychiton discolor). The relative ordering of maximum photosynthesis and conductance across species was not entirely predictable based on our current knowledge of the native habitats of each species: several other species had similar native climates to Jacaranda and honey locust, yet

  1. Establishment success of coexisting native and exotic trees under an experimental gradient of irradiance and soil moisture.

    Science.gov (United States)

    González-Muñoz, Noelia; Castro-Díez, Pilar; Fierro-Brunnenmeister, Natalia

    2011-10-01

    The exotic trees Ailanthus altissima, Robinia pseudoacacia, Acer negundo and Elaeagnus angustifolia coexist with the native trees Fraxinus angustifolia and Ulmus minor in river banks of central Spain. Similarly, the exotic trees Acacia dealbata and Eucalyptus globulus co-occur with the natives Quercus pyrenaica and Pinus pinaster in Northwest Spain. We aimed to identify the environmental conditions that favour or hamper the establishment success of these species. In spring 2008, seeds of the studied species were sown under an experimental gradient of light (100, 65, 35, 7% of full sunlight) combined with three levels of soil moisture (mean soil water potential = -0.97, -1.52 and -1.77 MPa.). During the first growing season we monitored seed emergence and seedling survival. We found that the effect of light on the establishment success was stronger than the effect of soil moisture. Both exotic and native species of central Spain showed a good performance under high light, A. negundo being the most shade tolerant. Water shortage diminished E. angustifolia and A. altissima success. Among NW Spain species, A. dealbata and P. pinaster were found to be potential competitors for colonizing high-irradiance scenarios, while Q. pyrenaica and E. globulus were more successful under moderate shade. High soil moisture favoured E. globulus but not A. dealbata establishment. These results contribute to understand some of the factors controlling for spatial segregation between coexisting native and exotic tree species, and can help to take decisions orientated to the control and management of these exotic species.

  2. Comparing the Sexual Reproductive Success of Two Exotic Trees Invading Spanish Riparian Forests vs. a Native Reference.

    Science.gov (United States)

    Cabra-Rivas, Isabel; Castro-Díez, Pilar

    2016-01-01

    A widely accepted hypothesis in invasion ecology is that invasive species have higher survival through the early stages of establishment than do non-invasive species. In this study we explore the hypothesis that the sexual reproductive success of the invasive trees Ailanthus altissima (Mill.) Swingle and Robinia pseudoacacia L. is higher than that of the native Fraxinus angustifolia Vahl., all three species coexisting within the riparian forests of Central Spain. We compared different stages of the early life cycle, namely seed rain, seed infestation by insects, seed removal by local fauna, seed germination under optimal conditions and seedling abundance between the two invasive trees and the native, in order to assess their sexual reproductive success. The exotic species did not differ from the native reference (all three species displaying high seed rain and undergoing seed losses up to 50% due to seed removal by the local fauna). Even if the exotic R. pseudoacacia showed a high percentage of empty and insect-parasited seeds along with a low seedling emergence and the exotic A. altissima was the species with more viable seeds and of higher germinability, no differences were found regarding these variables when comparing them with the native F. angustifolia. Unsuitable conditions might have hampered either seedling emergence and survival, as seedling abundance in the field was lower than expected in all species -especially in R. pseudoacacia-. Our results rather suggest that the sexual reproductive success was not higher in the exotic trees than in the native reference, but studies focusing on long-term recruitment would help to shed light on this issue.

  3. Pollination ecology of the invasive tree tobacco Nicotiana glauca: comparisons across native and non-native ranges

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    Jeff Ollerton

    2012-10-01

    Full Text Available Interactions with pollinators are thought to play a significant role in determining whether plant species become invasive, and ecologically generalised species are predicted to be more likely to invade than more specialised species. Using published and unpublished data we assessed the floral biology and pollination ecology of the South American native Nicotiana glauca (Solanaceae which has become a significant invasive of semi-arid parts of the world. In regions where specialised bird pollinators are available, for example hummingbirds in California and sunbirds in South Africa and Israel, N. glauca interacts with these local pollinators and sets seed by both out-crossing and selfing. In areas where there are no such birds, such as the Canary Islands and Greece, abundant viable seed is set by selfing, facilitated by the shorter stigma-anther distance compared to plants in native populations. Surprisingly, in these areas without pollinating birds, the considerable nectar resources are only rarely exploited by other flower visitors such as bees or butterflies, either legitimately or by nectar robbing. We conclude that Nicotiana glauca is a successful invasive species outside of its native range, despite its functionally specialised hummingbird pollination system, because it has evolved to become more frequently self pollinating in areas where it is introduced. Its invasion success is not predictable from what is known of its interactions with pollinators in its home range.

  4. Restoration of Degraded Soil in the Nanmangalam Reserve Forest with Native Tree Species: Effect of Indigenous Plant Growth-Promoting Bacteria

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    Andimuthu Ramachandran

    2016-01-01

    Full Text Available Restoration of a highly degraded forest, which had lost its natural capacity for regeneration, was attempted in the Nanmangalam Reserve Forest in Eastern Ghats of India. In field experiment, 12 native tree species were planted. The restoration included inoculation with a consortium of 5 native plant growth-promoting bacteria (PGPB, with the addition of small amounts of compost and a chemical fertilizer (NPK. The experimental fields were maintained for 1080 days. The growth and biomass varied depending on the plant species. All native plants responded well to the supplementation with the native PGPB. The plants such as Pongamia pinnata, Tamarindus indica, Gmelina arborea, Wrightia tinctoria, Syzygium cumini, Albizia lebbeck, Terminalia bellirica, and Azadirachta indica performed well in the native soil. This study demonstrated, by using native trees and PGPB, a possibility to restore the degraded forest.

  5. Restoration of Degraded Soil in the Nanmangalam Reserve Forest with Native Tree Species: Effect of Indigenous Plant Growth-Promoting Bacteria

    Science.gov (United States)

    Ramachandran, Andimuthu; Radhapriya, Parthasarathy

    2016-01-01

    Restoration of a highly degraded forest, which had lost its natural capacity for regeneration, was attempted in the Nanmangalam Reserve Forest in Eastern Ghats of India. In field experiment, 12 native tree species were planted. The restoration included inoculation with a consortium of 5 native plant growth-promoting bacteria (PGPB), with the addition of small amounts of compost and a chemical fertilizer (NPK). The experimental fields were maintained for 1080 days. The growth and biomass varied depending on the plant species. All native plants responded well to the supplementation with the native PGPB. The plants such as Pongamia pinnata, Tamarindus indica, Gmelina arborea, Wrightia tinctoria, Syzygium cumini, Albizia lebbeck, Terminalia bellirica, and Azadirachta indica performed well in the native soil. This study demonstrated, by using native trees and PGPB, a possibility to restore the degraded forest. PMID:27195310

  6. Decomposition of leaf litter from a native tree and an actinorhizal invasive across riparian habitats.

    Science.gov (United States)

    Harner, Mary J; Crenshaw, Chelsea L; Abelho, Manuela; Stursova, Martina; Shah, Jennifer J Follstad; Sinsabaugh, Robert L

    2009-07-01

    Dynamics of nutrient exchange between floodplains and rivers have been altered by changes in flow management and proliferation of nonnative plants. We tested the hypothesis that the nonnative, actinorhizal tree, Russian olive (Elaeagnus angustifolia), alters dynamics of leaf litter decomposition compared to native cottonwood (Populus deltoides ssp. wislizeni) along the Rio Grande, a river with a modified flow regime, in central New Mexico (U.S.A.). Leaf litter was placed in the river channel and the surface and subsurface horizons of forest soil at seven riparian sites that differed in their hydrologic connection to the river. All sites had a cottonwood canopy with a Russian olive-dominated understory. Mass loss rates, nutrient content, fungal biomass, extracellular enzyme activities (EEA), and macroinvertebrate colonization were followed for three months in the river and one year in forests. Initial nitrogen (N) content of Russian olive litter (2.2%) was more than four times that of cottonwood (0.5%). Mass loss rates (k; in units of d(-1)) were greatest in the river (Russian olive, k = 0.0249; cottonwood, k = 0.0226), intermediate in subsurface soil (Russian olive, k = 0.0072; cottonwood, k = 0.0031), and slowest on the soil surface (Russian olive, k = 0.0034; cottonwood, k = 0.0012) in a ratio of about 10:2:1. Rates of mass loss in the river were indistinguishable between species and proportional to macroinvertebrate colonization. In the riparian forest, Russian olive decayed significantly faster than cottonwood in both soil horizons. Terrestrial decomposition rates were related positively to EEA, fungal biomass, and litter N, whereas differences among floodplain sites were related to hydrologic connectivity with the river. Because nutrient exchanges between riparian forests and the river have been constrained by flow management, Russian olive litter represents a significant annual input of N to riparian forests, which now retain a large portion of slowly

  7. Effective Prediction of Errors by Non-native Speakers Using Decision Tree for Speech Recognition-Based CALL System

    Science.gov (United States)

    Wang, Hongcui; Kawahara, Tatsuya

    CALL (Computer Assisted Language Learning) systems using ASR (Automatic Speech Recognition) for second language learning have received increasing interest recently. However, it still remains a challenge to achieve high speech recognition performance, including accurate detection of erroneous utterances by non-native speakers. Conventionally, possible error patterns, based on linguistic knowledge, are added to the lexicon and language model, or the ASR grammar network. However, this approach easily falls in the trade-off of coverage of errors and the increase of perplexity. To solve the problem, we propose a method based on a decision tree to learn effective prediction of errors made by non-native speakers. An experimental evaluation with a number of foreign students learning Japanese shows that the proposed method can effectively generate an ASR grammar network, given a target sentence, to achieve both better coverage of errors and smaller perplexity, resulting in significant improvement in ASR accuracy.

  8. A new genus and species of leaf miner (Lepidoptera, Gracillariidae for Chile associated to the native tree Lithraea caustica

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    Enrique A. Mundaca

    2013-06-01

    Full Text Available A new genus and species of leaf miner (Lepidoptera, Gracillariidae for Chile associated to the native tree Lithraea caustica. We propose the new genus and species of Gracillariidae (Lepidoptera Hualpenia lithraeophaga Mundaca, Parra &Vargas gen. nov., sp. nov., leaf miner of Lithraea caustica (Mol. H. et Arn (Anacardiaceae occurring in southern central Chile. Aspects of the life cycle, adult and larval morphology, development and feeding habits of the new genus and species are also presented. We emphasise the uniqueness and importance of this new species for broadening the current knowledge on the Chilean fauna of Gracillariidae.

  9. Use of non-timber forest products from invasive alien Prosopis species(mesquite) and native trees in South Africa: implications for management

    Institute of Scientific and Technical Information of China (English)

    Ross; T; Shackleton; David; C; Le; Maitre; Brian; W; van; Wilgen; David; M; Richardson

    2015-01-01

    Background: Prosopis species have been introduced to many areas outside their native range to provide benefits to local communities. Several Prosopis species and their hybrids(hereafter "mesquite") have, however, become naturalised and invasive and now generate substantial costs. Management options are limited because of the complex conflicts of interest regarding benefits and costs. Management policies and strategies must take account of such conflicts, but further insights are needed on the dimensions of uses and impacts before such information can be usefully applied. Current policy in South Africa allows for the growth and use of mesquite in one province,but not in others where its control is mandatory. We report on a study to quantify the direct use and perceptions of non-timber forest products(NTFPs) from mesquite and native trees in South Africa.Methods: Semi-structures household interviews were conducted with various stakeholder groups to identify what tree products are used, to ascertain amounts used as well as to gauge perceptions of natural resource use between different tree species and use over time.Results: The direct household use value of native trees was higher than that of mesquite, and local stakeholders attached greater value to products from native trees than from mesquite. Therefore, native trees are and will still be preferentially harvested, and mesquite is unlikely to offer protection to native species by providing an alternative source of products. Mesquite pods do, however, provide valuable additional resources(fodder and medicinal products). The use of both native trees and mesquite is decreasing as the incomes of poorer households rise and as alternative energy sources become available. The benefits and reliance on mesquite are not as high as previously assumed and the impacts from mesquite invasions create large problems for local communities.Conclusion: This study provides further evidence that the impacts of mesquite exceed the

  10. Phytoremediation potential of chromium-containing tannery effluent-contaminated soil by native Indian timber-yielding tree species.

    Science.gov (United States)

    Manikandan, Muthu; Kannan, Vijayaraghavan; Mahalingam, Kanimozhi; Vimala, A; Chun, Sechul

    2016-01-01

    Twenty-six native Indian tree species that are used for the enhanced tree cover program of the forest department (Government of Tamilnadu, India) were screened for phytoremediation of tannery effluent-contaminated soil containing high chromium content. Out of 26 tree species tested, 10 timber-yielding tree species were selected for further phytoremediation monitoring. After a series of treatments with tannery effluent sludge, the chromium content was measured in the plant parts. The saplings of Acacia auriculiformis, Azadirachta indica, Albizzia lebbeck, Dalbergia sisso, and Thespesia populnea were identified as efficient bioaccumulators of chromium from Cr-contaminated soil. Acacia auriculiformis accumulates higher amounts of Cr in both the root and stem. Dalbergia sisso and T. populnea were found to accumulate higher quantity of Cr in the roots, whereas A. indica, A. richardiana, and A. lebbeck accumulate Cr in their stem. The stress response of the plant species was assessed by quantifying the antioxidative enzymes such as catalase, superoxide dismutase, glutathione reductase, and DHAR. Activity of all the enzymes was observed to gradually increase following treatment with tannery effluent sludge.

  11. Uptake and Translocation of Iron by Native Tree Species In A Constructed Wetland Treating Landfill Leachates

    Directory of Open Access Journals (Sweden)

    A. Snow

    2008-01-01

    Full Text Available A surface flow wetland was constructed in the Burnside Industrial Park, Dartmouth, Nova Scotia, to treat stormwater runoff from the surrounding watersheds which are comprised primarily of commercial properties and two former landfills. The objectives of this study were: (a to compare the uptake of iron by red maple, white birch and red spruce trees growing under flooded soil conditions in the constructed wetland and well drained soil conditions in a nearby reference site, (b to evaluate the seasonal variability of iron in these trees and (c to determine the distribution of iron in different compartments of these trees (leaves, twigs, branches, trunk wood, trunk bark and roots. The average iron concentrations in the aboveground compartments of red maple, white birch and red spruce trees were within the range of iron concentrations reported in the literature for these trees. Red maple, white birch and red spruce trees in the constructed wetland had significantly greater iron concentrations in their roots than the same species in the reference site. The average iron concentrations in the leaves of red maple trees in the constructed wetland and the reference site displayed an increasing trend towards the end of the growing season while the average iron concentrations in the twigs of red maple and white birch trees in the constructed wetland and the reference site displayed maximum concentrations at the beginning of the growing season. Red maple, white birch and red spruce trees in the constructed wetland retained a major portion of their overall iron concentration in their root systems.

  12. Seven new species of the Botryosphaeriaceae from baobab and other native trees in Western Australia.

    Science.gov (United States)

    Pavlic, Draginja; Wingfield, Michael J; Barber, Paul; Slippers, Bernard; Hardy, Giles E St J; Burgess, Treena I

    2008-01-01

    In this study seven new species of the Botryosphaeriaceae are described from baobab (Adansonia gibbosa) and surrounding endemic tree species growing in the Kimberley region of northwestern Australia. Members of the Botryosphaeriaceae were predominantly endophytes isolated from apparently healthy sapwood and bark of endemic trees; others were isolated from dying branches. Phylogenetic analyses of ITS and EF1-alpha sequence data revealed seven new species: Dothiorella longicollis, Fusicoccum ramosum, Lasiodiplodia margaritacea, Neoscytalidium novaehollandiae, Pseudofusicoccum adansoniae, P. ardesiacum and P. kimberleyense.

  13. Ozone stomatal flux and O3 concentration-based metrics for Astronium graveolens Jacq., a Brazilian native forest tree species.

    Science.gov (United States)

    Cassimiro, Jéssica C; Moura, Bárbara B; Alonso, Rocio; Meirelles, Sérgio T; Moraes, Regina M

    2016-06-01

    The current levels of surface ozone (O3) are high enough to negatively affect trees in large regions of São Paulo State, southeastern Brazil, where standards for the protection of vegetation against the adverse effects of O3 do not exist. We evaluated three O3 metrics - phytotoxic ozone dose (POD), accumulated ozone exposure over the threshold of 40 ppb h (AOT40), and the sum of all hourly average concentrations (SUM00) - for the Brazilian native tropical tree species Astronium graveolens Jacq. We used the DO3SE (Deposition of Ozone for Stomatal Exchange) model and calculated PODY for different thresholds (from 0 to 6 mmol O3 m(-2) PLA s(-1)), evaluating the model's performance through the relationship between measured and modelled conductance. The response parameters were: visible foliar injury, considered as incidence (% injured plants), severity (% injured leaves in relation to the number of leaves on injured plants), and leaf abscission. The model performance was suitable and significant (R(2) = 0.58; p < 0.001). POD0 was better correlated to incidence and leaf abscission, and SUM00 was better correlated to severity. The highest values of O3 concentration-based metrics (AOT40 and SUM00) did not coincide with those of POD0. Further investigation may improve the model and contribute to the proposition of a national standard for the protection of native species.

  14. Interactions with soil biota shift from negative to positive when a tree species is moved outside its native range.

    Science.gov (United States)

    Gundale, Michael J; Kardol, Paul; Nilsson, Marie-Charlotte; Nilsson, Urban; Lucas, Richard W; Wardle, David A

    2014-04-01

    Studies evaluating plant-soil biota interactions in both native and introduced plant ranges are rare, and thus far have lacked robust experimental designs to account for several potential confounding factors. Here, we investigated the effects of soil biota on growth of Pinus contorta, which has been introduced from Canada to Sweden. Using Swedish and Canadian soils, we conducted two glasshouse experiments. The first experiment utilized unsterilized soil from each country, with a full-factorial cross of soil origin, tree provenance, and fertilizer addition. The second experiment utilized gamma-irradiated sterile soil from each country, with a full-factorial cross of soil origin, soil biota inoculation treatments, tree provenance, and fertilizer addition. The first experiment showed higher seedling growth on Swedish soil relative to Canadian soil. The second experiment showed this effect was due to differences in soil biotic communities between the two countries, and occurred independently of all other experimental factors. Our results provide strong evidence that plant interactions with soil biota can shift from negative to positive following introduction to a new region, and are relevant for understanding the success of some exotic forest plantations, and invasive and range-expanding native species.

  15. Predicting the dynamics of a native Araucaria forest using a distance-independent individual tree-growth model

    Directory of Open Access Journals (Sweden)

    Enrique Orellana

    2016-05-01

    Full Text Available Background: In recent decades, native Araucaria forests in Brazil have become fragmented due to the conversion of forest to agricultural lands and commercial tree plantations. Consequently, the forest dynamics in this forest type have been poorly investigated, as most fragments are poorly structured in terms of tree size and diversity. Methods: We developed a distance-independent individual tree-growth model to simulate the forest dynamics in a native Araucaria forest located predominantly in southern Brazil. The data were derived from 25 contiguous plots (1 ha established in a protected area left undisturbed for the past 70 years. The plots were measured at 3-year intervals from their establishment in 2002. All trees above a 10-cm diameter at breast height were tagged, identified as to species, and measured. Because this forest type comprises hundreds of tree species, we clustered them into six ecological groups: understory, subcanopy, upper canopy shade-tolerant, upper canopy light-demanding, pioneer, and emergent. The diameter increment, survival, and recruitment sub-models were fitted for each species group, and parameters were implemented in a simulation software to project the forest dynamics. The growth model was validated using independent data collected from another research area of the same forest type. To simulate the forest dynamics, we projected the species group and stand basal areas for 50 years under three different stand-density conditions: low, average, and high. Results: Emergent species tended to grow in basal area, irrespective of the forest density conditions. Conversely, shade-tolerant species tended to decline over the years. Under low-density conditions, the model showed a growth tendency for the stand basal area, while under average-density conditions, forest growth tended to stabilize within 30 years. Under high-density conditions, the model indicated a decline in the stand basal area from the onset of the simulation

  16. Hydraulic redistribution study in two native tree species of agroforestry parklands of West African dry savanna

    Science.gov (United States)

    Bayala, Jules; Heng, Lee Kheng; van Noordwijk, Meine; Ouedraogo, Sibiri Jean

    2008-11-01

    Hydraulic redistribution (HR) in karité ( Vitellaria paradoxa) and néré ( Parkia biglobosa) tree species was studied by monitoring the soil water potential ( ψs) using thermocouple psychrometers at four compass directions, various distances from trees and at different soil depths (max depth 80 cm) during the dry seasons of 2004 and 2005. A modified WaNuLCAS model was then used to infer the amount of water redistribued based on ψs values. Tree transpiration rate was also estimated from sap velocity using thermal dissipative probes (TDP) and sapwood area, and the contribution of hydraulically redistributed water in tree transpiration was determined. The results revealed on average that 46% of the psychrometer readings under karité and 33% under néré showed the occurrence of HR for the two years. Soil under néré displayed significantly lower fluctuations of ψs (0.16 MPa) compared to soil under karité (0.21 MPa). The results of this study indicated that the existence of HR leads to a higher ψs in the plant rhizosphere and hence is important for soil water dynamics and plant nutrition by making more accessible the soluble elements. The simulation showed that the amount of water redistributed would be approximately 73.0 L and 247.1 L per tree per day in 2005 for karité and néré, and would represent respectively 60% and 53% of the amount transpired a day. Even though the model has certainly overestimated the volume of water hydraulically redistributed by the two species, this water may play a key role in maintaining fine root viability and ensuring the well adaptation of these species to the dry areas. Therefore, knowledge of the extent of such transfers and of the seasonal patterns is required and is of paramount importance in parkland systems both for trees and associated crops.

  17. Extending glacial refugia for a European tree: genetic markers show that Iberian populations of white elm are native relicts and not introductions

    OpenAIRE

    Fuentes-Utrilla, P.; Venturas, M; Hollingsworth, P.M.; Squirrell, J; Collada, C.; Stone, G. N.; Gil, L.

    2013-01-01

    Conservation policies usually focus on in situ protection of native populations, a priority that requires accurate assessment of population status. Distinction between native and introduced status can be particularly difficult (and at the same time, is most important) for species whose natural habitat has become both rare and highly fragmented. Here, we address the status of the white elm (Ulmus laevis Pallas), a European riparian tree species whose populations have been fragme...

  18. The Input-output Status and Farmers’Willingness to Choose Ecological Operation of Hickory

    Institute of Scientific and Technical Information of China (English)

    LIU Qiang; LI Shi-yong; WU Wei-guang

    2012-01-01

    This study takes Lin’an City which early carries out the experiment of ecological operation of hickory as the study site.On the basis of the input-output data on hickory and farmers’ land,we analyze the input-output status of hickory land which practises ecological operation,the operators’ willingness to accept ecological operation and the influencing factors.The results show that in the short term,ecological operation of hickory will have a certain negative impact on the economic benefits;within the experimental area,the degree of operators’ willingness to accept ecological operation of hickory is high,and the operators have a clear understanding of long-term comprehensive benefits which may be brought by ecological operation;the ecological experiment and demonstration of hickory have achieved certain results;family income level,characteristics of householders,education and training,and so on,are the main factors that affect the operators’ willingness to choose ecological operation.Finally,for how to further improve the promotion efficiency of ecological operation of hickory,we put forth some constructive recommendations.

  19. Selection of native trees for intercropping with coffee in the Atlantic Rainforest biome

    NARCIS (Netherlands)

    Souza, de H.N.; Cardoso, I.M.; Fernandes, J.M.; Garcia, F.C.P.; Bonfim, V.R.; Santos, A.C.; Carvalho, A.F.; Mendonca, E.S.

    2010-01-01

    A challenge in establishing agroforestry systems is ensuring that farmers are interested in the tree species, and are aware of how to adequately manage these species. This challenge was tackled in the Atlantic Rainforest biome (Brazil), where a participatory trial with agroforestry coffee systems wa

  20. Nodulation of tree legumes and the ecology of their native rhizobial populations in tropical soils

    NARCIS (Netherlands)

    Bala, A.; Murphy, P.J.; Osunde, A.O.; Giller, K.E.

    2003-01-01

    A legume introduced into a new area will only form nodules and fix nitrogen if compatible rhizobia are present in the soil. Using 25 (60 in the case of Sesbania sesban) soils sampled from tropical areas of Africa, Asia and Latin America, we examined the nodulation of four agroforestry tree species (

  1. [Characterization of rhizobia causing nodules on leguminous trees native to Uruguay using the rep-PCR technique].

    Science.gov (United States)

    Rodríguez, A; Frioni, L

    2003-01-01

    Methods for identifying and following microorganisms in the environment such as soils, water and plant association have been highly developed in recent years. In this study, we used rep-PCR for the characterization of Rhizobium bacteria isolated from legume trees native of Uruguay which permitted to follow them in plant inoculation assays. Among the primers used, ERIC and BOX1AR, the latter allowed the differentiation of isolates from different legumes and the finding of a high level of homology among rhizobia that nodulate the same legume species. Besides, it demonstrated that the profiles of the isolates recovered from nodules of Acacia caven, were identical to the ones used as inoculants; this confirmed the efficiency of these methods to follow these diazotrophs in the environment.

  2. Vulnerability of native savanna trees and exotic Khaya senegalensis to seasonal drought.

    Science.gov (United States)

    Arndt, Stefan K; Sanders, Gregor J; Bristow, Mila; Hutley, Lindsay B; Beringer, Jason; Livesley, Stephen J

    2015-07-01

    Seasonally dry ecosystems present a challenge to plants to maintain water relations. While native vegetation in seasonally dry ecosystems have evolved specific adaptations to the long dry season, there are risks to introduced exotic species. African mahogany, Khaya senegalensis Desr. (A. Juss.), is an exotic plantation species that has been introduced widely in Asia and northern Australia, but it is unknown if it has the physiological or phenotypic plasticity to cope with the strongly seasonal patterns of water availability in the tropical savanna climate of northern Australia. We investigated the gas exchange and water relations traits and adjustments to seasonal drought in K. senegalensis and native eucalypts (Eucalyptus tetrodonta F. Muell. and Corymbia latifolia F. Muell.) in a savanna ecosystem in northern Australia. The native eucalypts did not exhibit any signs of drought stress after 3 months of no rainfall and probably had access to deeper soil moisture late into the dry season. Leaf water potential, stomatal conductance, transpiration and photosynthesis all remained high in the dry season but osmotic adjustment was not observed. Overstorey leaf area index (LAI) was 0.6 in the native eucalypt savanna and did not change between wet and dry seasons. In contrast, the K. senegalensis plantation in the wet season was characterized by a high water potential, high stomatal conductance and transpiration and a high LAI of 2.4. In the dry season, K. senegalensis experienced mild drought stress with a predawn water potential -0.6 MPa. Overstorey LAI was halved, and stomatal conductance and transpiration drastically reduced, while minimum leaf water potentials did not change (-2 MPa) and no osmotic adjustment occurred. Khaya senegalensis exhibited an isohydric behaviour and also had a lower hydraulic vulnerability to cavitation in leaves, with a P50 of -2.3 MPa. The native eucalypts had twice the maximum leaf hydraulic conductance but a much higher P50 of -1.5 MPa

  3. Drought tolerance of Acacia karroo, a native tree species to South Africa,in Beijing

    Institute of Scientific and Technical Information of China (English)

    Yang Ying; Janusz Zwolinski; Yin Wei-lun; Wang Hua-fang

    2006-01-01

    Acacia karroo is an indigenous, strong drought-tolerant and widely planted tree in South Africa. In order to match the plant with its adaptation to forest sites in China, it is important to know the drought-tolerance of this species under Chinese forest site conditions. Our study was carried out in cinnamon soils in Beijing and with Platycladus orientalis, the most drought-tolerant tree in Beijing, as control. Physiological parameters of young plants of the trees were measured and divided into three groups in response to soil drying. The first group included root activity, ABA content in roots and peroxidase (POD) activity in leaves. Their values changed similarly to those of P. orientalis and dramatically increased to maximum values when the soil water content (SWC) decreased from its normal level of 20% to 7.6% where the three indices decreased dramatically when SWC was reduced further from 7.6%. The second group of parameters included the contents of proline, soluble protein and malondialdehyde (MDA). Their values showed greater variation than those of P. orientalis and significantly increased when SWC decreased from 20% in response to soil drying. However,the proline and soluble protein contents fluctuated in A. karroo at a lower level than those in P. orientalis. In contrast, the content of MDA in A. karroo was much higher than that in P. orientalis which almost did not increase in the drying soil. The third group of parameters consisted of soluble sugar, superoxide dismutase (SOD) and catalase (CAT). These parameters showed greater diversity and fluctuations among the three varieties of A. karroo compared with the control in response to soil drying. These results suggest that A. karroo is characterized as a strong, drought tolerant species in most of physiological parameters but weaker than P.orientalis in membrane lipid antioxidation.

  4. Contrasting secondary growth and water use efficiency patterns in native and exotic trees co-occurring in inner Spain riparian forests

    NARCIS (Netherlands)

    González Muñoz, N.; Linares, J.C.; Castro-Diez, P.; Sass-Klaassen, U.G.W.

    2015-01-01

    Aim of study: The invasive trees Ailanthus altissima and Robinia pseudoacacia are widely spreading in inner Spain riparian forests, where they co-occur with the natives Fraxinus angustifolia and Ulmus minor. In a climate change context, we aimed to identify some of the species traits that are leadin

  5. Contrasting secondary growth and water use efficiency patterns in native and exotic trees co-occurring in inner Spain riparian forests

    NARCIS (Netherlands)

    González Muñoz, N.; Linares, J.C.; Castro-Diez, P.; Sass-Klaassen, U.G.W.

    2015-01-01

    Aim of study: The invasive trees Ailanthus altissima and Robinia pseudoacacia are widely spreading in inner Spain riparian forests, where they co-occur with the natives Fraxinus angustifolia and Ulmus minor. In a climate change context, we aimed to identify some of the species traits that are

  6. Palms versus trees: water use characteristics of native fruit-bearing plant species in the Central Amazon

    Science.gov (United States)

    Kunert, N.; Barros, P.; Higuchi, N.

    2012-12-01

    Native fruiting plants are widely cultivated in the Amazon but only little information on their water use characteristics can be found in the literature. Due to the growing local consumption and the increasing popularity for new "exotic" fruits all over Brazil and worldwide, additional new plantations cultivating such fruit-bearing species might be established in the Amazon in the future. These new plantations will affect the water table of the cultivated areas, however, the impact of these changes on the regional hydrology are not known. We, therefore, decided to study plant water use characteristics of two native fruit plants commonly occurring in the Amazon region, a tree species (Cupuaçu, Theobroma grandiflorum, (Willd. ex Spreng.) Schum., Malvaceae) and a palm species (Açai, Euterpe oleraceae Mart., Arecaceae). This study was conducted in a fruit plantation close to the city of Manaus, in the Central Amazon, Brazil. The objectives of our study were 1) to compare variables controlling plant water use and 2) to identify differences in water use between woody monocot and dicot plant species. We chose three representative individuals with well-sun-exposed crowns for each species, which were equipped with Granier-type thermal dissipation probes to measure sap flux density continuously for six weeks from August 1st 2011 until September 6th 2011. We used a simple sap flux model with two environmental variables, photosynthetic photon flux density and vapor pressure deficit, to compare sap flux densities between species. We achieved a good model fit and modeled sap flux densities corresponded very well with the actual measured values. No significant differences among species in sap flux densities were indicated by the model. Overall, palms had a 3.5 fold higher water consumption compared to trees with similar diameter. Water use scaled independent from species with the size of the conductive xylem area (r2 = 0.85), so that the higher water use of the palms was

  7. Effectiveness of native arbuscular mycorrhiza on the growth of four tree forest species from the Santa Marta Mountain, Veracruz (Mexico

    Directory of Open Access Journals (Sweden)

    Yolanda Retama-Ortiz

    2017-05-01

    amazonia and Cojoba arborea showed greater response to the inoculation of AMF, they showed more height, number of leaves and more total dry weight; whereas C. alliodora appears to be low dependent on AMF. Highlights: Diversispora aurantia and Glomus aggregatum are reported by the first time from Mexican humid tropics. Native AMF have potential biotechnological application. The mycorrhizal consortium six (Glomus and Acaulospora was the more effective in promoting the development of the four tree species used in the experiment.

  8. Trees

    Science.gov (United States)

    Al-Khaja, Nawal

    2007-01-01

    This is a thematic lesson plan for young learners about palm trees and the importance of taking care of them. The two part lesson teaches listening, reading and speaking skills. The lesson includes parts of a tree; the modal auxiliary, can; dialogues and a role play activity.

  9. Observations on the biology and distribution of Uresiphita reversalis (Lepidoptera, Crambidae, a defoliator of the native tree Calia secundiflora in México

    Directory of Open Access Journals (Sweden)

    Ignacio P. Chávez-Sánchez

    2014-09-01

    Full Text Available Observations on the biology and distribution of Uresiphita reversalis (Lepidoptera, Crambidae, a defoliator of the native tree Calia secundiflora in México. Uresiphita reversalis (Guenée, 1854 feeding on Calia secundiflora (Ortega Yakovlev is recorded for the first time in the state of Hidalgo, Mexico. New aspects regarding the life cycle, feeding behaviour, geographical distribution and host plant damage by U. reversalis on C. secundiflora are here presented and discussed.

  10. Contrasting secondary growth and water-use efficiency patterns in native and exotic trees co-occurring in inner Spain riparian forests

    Directory of Open Access Journals (Sweden)

    Noelia González-Muñoz

    2015-04-01

    Full Text Available Aim of study: The invasive trees Ailanthus altissima and Robinia pseudoacacia are widely spreading in inner Spain riparian forests, where they co-occur with the natives Fraxinus angustifolia and Ulmus minor. In a climate change context, we aimed to identify some of the species traits that are leading these species to success (Basal Area Increment (BAI and water-use efficiency (iWUE. We also aimed to describe the main environmental variables controlling studied species BAI. Area of study: Riparian forests of central Spain Material and Methods: We measured tree-ring width and converted it to basal area increment (BAI; intrinsic water-use efficiency (iWUE was estimated from tree ring carbon isotopes (δ13C. We compared the BAI and iWUE of the last 20 years between origins (native vs exotic and among species. For each species, we evaluated iWUE and BAI relationships. Linear mixed-effect models were performed to identify the main environmental variables (temperature, precipitation, river flow affecting BAI. Main result: Native trees showed higher mean BAI than invaders, mainly due to the rising growth rate of U. minor. Invaders showed higher mean iWUE than natives. We did not find significant correlations between iWUE and BAI in any case. Warm temperatures in autumn positively affected the BAI of the natives, but negatively that of the invaders. Research highlights: The contrasting effect of autumn temperatures on native and invasive species BAI suggests that invaders will be more hampered by the rising temperatures predicted for this century. The higher iWUE found for the invaders did not translate into increased radial growth, suggesting that drought stress may have prevented them of taking advantage of increased atmospheric CO2 for a faster growth. These findings point out that neither climate change nor rising CO2 seem to enhance the success of study invasive species over the natives in riparian forests of central Spain. Furthermore, the low BAI

  11. LEAF LITTER BREAKDOWN RATES AND ASSOCIATED FAUNA OF NATIVE AND EXOTIC TREES USED IN NEOTROPICAL RIPARIA REFORESTATION

    Directory of Open Access Journals (Sweden)

    Nataly Gutiérrez Isaza

    2013-09-01

    Full Text Available ABSTRACT A signature of globalization is the prevalence of exotic trees along reforested urban and rural riparian zones in the Neotropics, but little is known about the instream processing of its leaf litter. In this study, leaf litter breakdown rates were measured during 35 days using mesh bags within a reference headwater stream for seven exotic and three native tree species commonly used in urban and rural reforestation. Artocarpus altilis, Schefflera actinophylla and Terminalia catappa scored the highest mass loss rates (>85 %; mean life: t50 85 %; vida media: t50 <15 d, mientras que las menores tasas las obtuvieron Cecropia sp. y Cespedesia macrophylla (pérdida de masa =36 y 15 %; t50 =58 y 153 d, respectivamente. Sin embargo, se observó una amplia gama de tasas de pérdida de masa entre las diez especies estudiadas. La proporción carbono:fósforo (C:P y la dureza de la hojarasca fueron los mejores predictores de las tasas de pérdida de masa. Sin embargo, estas características no se correlacionaron con los muy bajos valores de abundancia y diversidad de macroinvertebrados, y la escasez de morfotipos de insectos clasificados como fragmentadores. Por lo tanto, los controles físicos parecen ser más importantes que los biológicos para explicar la variabilidad de las tasas de pérdida de masa; y, las especies con tasas más bajas podrían estar proveyendo hábitat, más que alimento para las especies de insectos acuáticos, principalmente los recolectores. Este estudio sugiere que la reforestación ribereña propagará efectos específicos sobre los procesos dentro del cauce dependiendo de las especies de árbol plantadas mediados por la calidad de la hojarasca, los cuales deberían ser considerados para mejorar las estrategias de reforestación. Estudios futuros deben someter a prueba si existen diferencias en las tasas de fragmentación y colonización de macroinvertebrados entre especies de hojarasca de diferente origen (nativa vs. exótica.

  12. The structure of tree stand and wood-destroying fungi of native pine biogeocoenoses of the Russian plain

    Directory of Open Access Journals (Sweden)

    V. G. Storozhenko

    2015-08-01

    Full Text Available The author considered age structures of virgin indigenous pine forests of natural origin as well as plantations in the subzones of taiga, zones of mixed forests, deciduous forests and forest-steppe of the Russian plain. Native pine forests are heterogeneous by their structural characteristics. This heterogeneity is caused by high demands of the species to understory light requirements as well as by frequent pyrogenic influence that determine the age structure of stand forests. Virgin pine forests have up to 14 age generations and from 5 to 20 % of stand trees affected by fungi of biotrophic complex. That has a direct connection with their dynamic status. In the pine forests of digressive dynamic faze, where the initial age generations accommodate the major biomass amount, this volume may grow up to 50 %. Pine species planted discounting regularities of formation of stable forest communities are subject to spotty attacks by fungi of biotrophic complex. A species composition of wood-destroying fungi of biotrophic complex causing rot defects of pines in the entire longitudinal gradient of pine distribution within the Russian Plain stays virtually unchanged. Significant changes can be noted only in the occurrence of certain types of wood destroying fungi. The main types of wood biotrophic fungi include: Climacocystis borealis (Fr. Kotl. et Pouzar, Heterobasidion annosum (Fr. Bref., Phaeolus schweinitzii (Fr. Pat.; Porodaedalea chrysoloma (Fr. Fiasson et Niemelä; Phellinus pini (Thore: Fr. A. Ames [= Porodaedalea pini (Brot.: Fr. Murrill]. In the uneven-aged pine forests of natural origin, mottled butt rot does not form drying out spots and exists in the stands as an ordinary component of the total biotrophic defeat. Wood-destroying fungi of biotrophic complex are evolutionary determined as one of the endogenic mechanisms of destruction of unstable forest structures and formation of stable ones. The author also evaluated the volumes of biotrophic

  13. Effect of forest fragmentation on microsporogenesis and pollen viability in Eugenia uniflora, a tree native to the Atlantic Forest.

    Science.gov (United States)

    de Almeida, D J; Faria, M V; da Silva, P R

    2012-12-06

    Habitat fragmentation, caused by the expansion of agriculture in natural areas, may be one of the strongest impacts humans have on the ecosystem. These changes can decrease the number of individuals in a population, leading to endogamy. In allogamous species, endogamy can have a negative effect on reproductive capacity. In this study, we analyzed the effects of forest fragmentation on microsporogenesis and pollen viability in Eugenia uniflora L., a tree species native to the Atlantic Forest. We analyzed 4 populations, 3 of which were connected by forest corridors and 1 of which was isolated by agricultural fields on all sides. For microsporogenesis analysis, 9000 meiocytes representing all stages of meiosis were evaluated. To perform the pollen viability test, we evaluated 152,000 pollen grains. Microsporogenesis was stable in plants from populations that were connected by forest corridors (abnormalities, less than 6%), while microsporogenesis in plants from the isolated population showed a higher level of abnormalities (13-29%). Average pollen viability was found to be more than 93% in the non-isolated populations and 82.62% in the isolated population. The χ(2) test showed that, in the isolated population, the meiotic index was significantly lower than that in the non-isolated populations (P = 0.03). The analysis of variance for the percentage of viable pollen grains confirmed the significant difference between the isolated and non-isolated populations. Our data show that forest fragmentation has a direct effect on microsporogenesis and pollen viability in E. uniflora and can directly influence the reproductive capacity of isolated populations of this species.

  14. Trees

    OpenAIRE

    Henri Epstein

    2016-01-01

    An algebraic formalism, developed with V. Glaser and R. Stora for the study of the generalized retarded functions of quantum field theory, is used to prove a factorization theorem which provides a complete description of the generalized retarded functions associated with any tree graph. Integrating over the variables associated to internal vertices to obtain the perturbative generalized retarded functions for interacting fields arising from such graphs is shown to be possible for a large cate...

  15. Trees

    OpenAIRE

    Epstein, Henri

    2016-01-01

    An algebraic formalism, developped with V. Glaser and R. Stora for the study of the generalized retarded functions of quantum field theory, is used to prove a factorization theorem which provides a complete description of the generalized retarded functions associated with any tree graph. Integrating over the variables associated to internal vertices to obtain the perturbative generalized retarded functions for interacting fields arising from such graphs is shown to be possible for a large cat...

  16. Trees

    CERN Document Server

    Epstein, Henri

    2016-01-01

    An algebraic formalism, developped with V.~Glaser and R.~Stora for the study of the generalized retarded functions of quantum field theory, is used to prove a factorization theorem which provides a complete description of the generalized retarded functions associated with any tree graph. Integrating over the variables associated to internal vertices to obtain the perturbative generalized retarded functions for interacting fields arising from such graphs is shown to be possible for a large category of space-times.

  17. The relationships between microbiological attributes and soil and litter quality in pure and mixed stands of native tree species in southeastern Bahia, Brazil.

    Science.gov (United States)

    Gama-Rodrigues, Emanuela F; Gama-Rodrigues, Antonio Carlos; Barros, Nairam F; Moço, Maria Kellen S

    2011-11-01

    This study was conducted to link soil and litter microbial biomass and activity with soil and litter quality in the surface layer for different pure and mixed stands of native tree species in southeastern Bahia, Brazil. The purpose of the study was to see how strongly the differences among species and stands affect the microbiological attributes of the soil and to identify how microbial processes can be influenced by soil and litter quality. Soil and litter samples were collected from six pure and mixed stands of six hardwood species (Peltogyne angustifolia, Centrolobium robustum, Arapatiella psilophylla, Sclerolobium chrysophyllum, Cordia trichotoma, Macrolobium latifolium) native to the southeastern region of Bahia, Brazil. In plantations of native tree species in humid tropical regions, the immobilization efficiency of C and N by soil microbial biomass was strongly related to the chemical quality of the litter and to the organic matter quality of the soil. According to the variables analyzed, the mixed stand was similar to the natural forest and dissimilar to the pure stands. Litter microbial biomass represented a greater sink of C and N than soil microbial biomass and is an important contributor of resources to tropical soils having low C and N availability.

  18. Soils mediate the impact of fine woody debris on invasive and native grasses as whole trees are mechanically shredded into firebreaks in piñon-juniper woodlands

    Science.gov (United States)

    Aanderud, Zachary T.; Schoolmaster, Donald R.; Rigby, Deborah; Bybee, Jordon; Campbell, Tayte; Roundy, Bruce A.

    2017-01-01

    To stem wildfires, trees are being mechanically shredded into firebreaks with the resulting fine woody debris (FWD) potentially exerting immense control over soil and plants. We linked FWD-induced changes in microbial activity and nutrient availability to the frequency of Bromus tectorum and three native, perennial grasses across 31 piñon-juniper woodlands, UT, USA. Using a series of mixed models, we found that FWD increased the frequency of three of the four grasses by at least 12%. Deep, as opposed to shallow, soils mediated frequencies following FWD additions but only partially explained the variation in Bromus and Pseudoroegneria spicata. Although fertile areas associated with tree-islands elicited no response, FWD-induced increases in nitrogen mineralization in deep soils (15–17 cm) caused the frequency of the exotic and Pseudoroegneria to rise. Higher phosphorus availability in FWD-covered surface soils (0–2 cm) had no impact on grasses. FWD altered deep soil respiration, and deep and shallow microbial biomass structuring Pseudoroegneria frequencies, suggesting that microorganism themselves regulated Pseudoroegneria. The positive effects of FWD on grass frequencies intensified over time for natives but diminished for Bromus. Our results demonstrate that microorganisms in deeper soils helped mediate species-specific responses to disturbance both facilitating exotic invasion and promoting native establishment.

  19. Hickory, N.C., Receives $200,000 EPA Brownfield Grants to Revitalize, Strengthen Local Economy

    Science.gov (United States)

    ATLANTA - At a press conference in Huntington, W.Va., today, the U.S. Environmental Protection Agency (EPA) announced a $200,000 Brownfields Area-Wide Planning (AWP) grant to the City of Hickory, N.C., for reuse planning that includes residential an

  20. Influence of Removal of a Non-native Tree Species Mimosa caesalpiniifolia Benth. on the Regenerating Plant Communities in a Tropical Semideciduous Forest Under Restoration in Brazil

    Science.gov (United States)

    Podadera, Diego S.; Engel, Vera L.; Parrotta, John A.; Machado, Deivid L.; Sato, Luciane M.; Durigan, Giselda

    2015-11-01

    Exotic species are used to trigger facilitation in restoration plantings, but this positive effect may not be permanent and these species may have negative effects later on. Since such species can provide a marketable product (firewood), their harvest may represent an advantageous strategy to achieve both ecological and economic benefits. In this study, we looked at the effect of removal of a non-native tree species ( Mimosa caesalpiniifolia) on the understory of a semideciduous forest undergoing restoration. We assessed two 14-year-old plantation systems (modified "taungya" agroforestry system; and mixed plantation using commercial timber and firewood tree species) established at two sites with contrasting soil properties in São Paulo state, Brazil. The experimental design included randomized blocks with split plots. The natural regeneration of woody species (height ≥0.2 m) was compared between managed (all M. caesalpiniifolia trees removed) and unmanaged plots during the first year after the intervention. The removal of M. caesalpiniifolia increased species diversity but decreased stand basal area. Nevertheless, the basal area loss was recovered after 1 year. The management treatment affected tree species regeneration differently between species groups. The results of this study suggest that removal of M. caesalpiniifolia benefited the understory and possibly accelerated the succession process. Further monitoring studies are needed to evaluate the longer term effects on stand structure and composition. The lack of negative effects of tree removal on the natural regeneration indicates that such interventions can be recommended, especially considering the expectations of economic revenues from tree harvesting in restoration plantings.

  1. Increases in soil water content after the mortality of non-native trees in oceanic island forest ecosystems are due to reduced water loss during dry periods.

    Science.gov (United States)

    Hata, Kenji; Kawakami, Kazuto; Kachi, Naoki

    2016-03-01

    The control of dominant, non-native trees can alter the water balance of soils in forest ecosystems via hydrological processes, which results in changes in soil water environments. To test this idea, we evaluated the effects of the mortality of an invasive tree, Casuarina equisetifolia Forst., on the water content of surface soils on the Ogasawara Islands, subtropical islands in the northwestern Pacific Ocean, using a manipulative herbicide experiment. Temporal changes in volumetric water content of surface soils at 6 cm depth at sites where all trees of C. equisetifolia were killed by herbicide were compared with those of adjacent control sites before and after their mortality with consideration of the amount of precipitation. In addition, the rate of decrease in the soil water content during dry periods and the rate of increase in the soil water content during rainfall periods were compared between herbicide and control sites. Soil water content at sites treated with herbicide was significantly higher after treatment than soil water content at control sites during the same period. Differences between initial and minimum values of soil water content at the herbicide sites during the drying events were significantly lower than the corresponding differences in the control quadrats. During rainfall periods, both initial and maximum values of soil water contents in the herbicided quadrats were higher, and differences between the maximum and initial values did not differ between the herbicided and control quadrats. Our results indicated that the mortality of non-native trees from forest ecosystems increased water content of surface soils, due primarily to a slower rate of decrease in soil water content during dry periods.

  2. An Archaeological Survey of the Shoreline at Public Use Areas Pomme de Terre Lake, Hickory and Polk Counties, Missouri

    Science.gov (United States)

    1988-01-01

    O 1C A II Copy Pomme de Terre Lake US Army Corps Missouri of Engineers Kansas City District Fischer-Stein Associates, Inc. Carbondale, Illinois An...Archaeological Survey of Ou The Shoreline at Public Use Areas Pomme de Terre Lake, Hickory and Polk Counties, Missouri I’I DISRIBU11ON STA7EMIENIT DT!C...of shore- line at nine Corps of Engineer Public Use Areas at Pomme de Terre Lake, Hickory and Polk counties, Missouri, is presented. Previous

  3. Detection of Drought-Induced Hickory Disturbances in Western Lin An County, China, Using Multitemporal Landsat Imagery

    Directory of Open Access Journals (Sweden)

    Zhenyuan Xi

    2016-04-01

    Full Text Available Hickory plantations play an important role in improving local farmers’ economic conditions, but extreme drought in July–August 2013 seriously influenced hickory nut production. It is necessary to understand the extent and magnitude of this drought-induced hickory disturbance through mapping its spatial distribution using remote sensing data. This paper proposes a new approach to examine hickory disturbance based on multitemporal Landsat imagery. Ratios of green vegetation to soil fractions were calculated, in which the green vegetation and soil fractions were extracted from Landsat multispectral imagery using the linear spectral mixture analysis approach. We used the differences between before-drought and after-drought ratios to detect hickory disturbances. Four disturbance levels—non-disturbance, light, medium, and severe—were grouped according to the field survey data. The spatial distribution of these four levels was developed using the ratio-based approach. The result indicates that this approach is effective to detect drought-induced hickory disturbance and may be transferred to detect other kinds of disturbances, such as forest disease and selective logging. Cautions should be taken to properly select image acquisition dates and the change detection period, in addition to the approach itself.

  4. Host heterogeneity influences the impact of a non-native disease invasion on populations of a foundation tree species

    Science.gov (United States)

    Jules, Erik S.; Carroll, Allyson L.; Garcia, Andrea M.; Steenbock, Christopher M.; Kauffman, Matthew J.

    2014-01-01

    Invasive pathogens are becoming increasingly important in forested ecosystems, yet they are often difficult to study because of their rapid transmission. The rate and extent of pathogen spread are thought to be partially controlled by variation in host characteristics, such as when host size and location influence susceptibility. Few host-pathogen systems, however, have been used to test this prediction. We used Port Orford cedar (Chamaecyparis lawsoniana), a foundation tree species in riparian areas of California and Oregon (USA), and the invasive oomycete Phytophthora lateralis to assess pathogen impacts and the role of host characteristics on invasion. Across three streams that had been infected for 13–18 years by P. lateralis, we mapped 2241 trees and determined whether they had been infected using dendrochronology. The infection probability of trees was governed by host size (diameter at breast height [DBH]) and geomorphic position (e.g., active channel, stream bank, floodplain, etc.) similarly across streams. For instance, only 23% of trees DBH were infected, while 69% of trees ≥20 cm DBH were infected. Presumably, because spores of P. lateralis are transported downstream in water, they are more likely to encounter well-developed root systems of larger trees. Also because of this water-transport of spores, differences in infection probability were found across the geomorphic positions: 59% of cedar in the active channel and the stream bank (combined) were infected, while 23% of trees found on higher geomorphic types were infected. Overall, 32% of cedar had been infected across the three streams. However, 63% of the total cedar basal area had been killed, because the greatest number of trees, and the largest trees, were found in the most susceptible positions. In the active channel and stream bank, 91% of the basal area was infected, while 46% was infected across higher geomorphic positions. The invasion of Port Orford cedar populations by

  5. Leaf litter decomposition of native and introduced tree species of contrasting quality in headwater streams: how does the regional setting matter?

    Science.gov (United States)

    Casas, J Jesús; Larrañaga, Aitor; Menéndez, Margarita; Pozo, Jesús; Basaguren, Ana; Martínez, Aingeru; Pérez, Javier; González, José M; Mollá, Salvador; Casado, Carmen; Descals, Enrique; Roblas, Neftalí; López-González, J Antonio; Valenzuela, J Luis

    2013-08-01

    Terrestrial plant litter is important in sustaining stream food webs in forested headwaters. Leaf litter quality often decreases when native species are replaced by introduced species, and a lower quality of leaf litter inputs may alter litter decomposition at sites afforested with non-native species. However, since detritivore composition and resource use plasticity may depend on the prevalent litter inputs, the extent of the alteration in decomposition can vary between streams. We tested 2 hypotheses using 2 native and 3 introduced species of tree differing in quality in 4 Iberian regions with contrasting vegetational traits: 1) decomposition rates of all plant species would be higher in regions where streams normally receive litter inputs of lower rather than higher quality; 2) a higher resource-use plasticity of detritivores in regions vegetated with plants of lower litter quality will cause a greater evenness in decomposition rates among plant species compared to regions where streams normally receive higher-quality plant litter inputs. Results showed a highly consistent interspecific ranking of decomposition rates across regions driven by litter quality, and a significant regional effect. Hypothesis 1 was supported: decomposition rates of the five litter types were generally higher in streams from regions vegetated with species producing leaf litter of low quality, possibly due to the profusion of caddisfly shredders in their communities. Hypothesis 2 was not supported: the relative differences in decomposition rates among leaf litter species remained essentially unaltered across regions. Our results suggest that, even in regions where detritivores can be comparatively efficient using resources of low quality, caution is needed particularly when afforestation programs introduce plant species of lower litter quality than the native species.

  6. Genomic sequencing and microsatellite marker development for Boswellia papyrifera, an economically important but threatened tree native to dry tropical forests

    NARCIS (Netherlands)

    Addisalem, A.B.; Esselink, G.; Bongers, F.; Smulders, M.J.M.

    2015-01-01

    Microsatellite (or simple sequence repeat, SSR) markers are highly informative DNA markers often used in conservation genetic research. Next-generation sequencing enables efficient development of large numbers of SSR markers at lower costs. Boswellia papyrifera is an economically important tree spec

  7. Does litterfall from native trees support rainfed agriculture? Analysis of Ficus trees in agroforestry systems of southern dry agroclimatic zone of Karnataka, southern India

    Institute of Scientific and Technical Information of China (English)

    B.Dhanya; Syam Viswanath; Seema Purushothaman

    2013-01-01

    Trees of the genus Ficus,integral components of indigenous rainfed agro-ecosystems of the southern dry agro-climatic zone of Kamataka,southern India,have traditionally been associated with the ecological service of soil quality enhancement in addition to various direct use benefits.We assessed the soil enrichment service of Ficus benghalensis L.a common Ficus species in these agroforestry systems,by quantifying nutrient return via litter fall.Litterfall estimation and chemical analysis of litter showed that F.benghalensis trees produce 3,512 kg·ha-1 of litter annually which,on decomposition,can satisfy up to 76.70 % of N,20.24% of P and 67.76% of K requirements of dryland crops annually per hectare.This can lead to an avoided cost of compost of US $ 36.46ha-1·a-1 in dryland farming systems.The slow rate of decay of Ficus litter,as revealed in litter decomposition studies indicates its potential as ideal mulch for dryland soils.We discuss the complementarity between Ficus litterfall and cropping patterns in Mandya,and its implications for rainfed agricultural systems.

  8. Natural and Human-Induced Dynamics on Big Hickory Island, Florida

    Directory of Open Access Journals (Sweden)

    Tiffany M. Roberts Briggs

    2016-02-01

    Full Text Available Big Hickory Island, located in Lee County along the mixed-energy west Florida coast, experiences high long-term rates of shoreline recession, with much of the erosion concentrated along the central and southern portions of the island. In 2013, approximately 86,300 cubic meters of sand from an adjacent tidal inlet to the north were placed along 457 m to restore the beach and dune system. In an effort to combat erosion, seven concrete king-pile groins with adjustable panels were constructed subsequent to the completion of the beach nourishment. Natural and human-induced dynamics of Big Hickory Island are discussed through analysis of shoreline and morphologic change using historic aerial photographs and topographic and bathymetric field surveys of the recent beach erosion mitigation project. Although much of the long-term anomalously high rates of erosion for the area are related to natural interchanges between the sand resources of the barrier islands and adjacent ebb tidal shoals, additional reduction in sand supply is a result of human-interventions updrift of Big Hickory over the last several decades. The coupled natural and anthropogenic influences are driving the coastal processes toward a different morphodynamic state than would have occurred under natural processes alone.

  9. Cloning and bioinformatics analysis of CcPILS gene of Hickory (Carya cathayensis)

    Science.gov (United States)

    Guo, Wenbin; Yuan, Huwei; Gao, Liuxiao; Guo, Haipeng; Qiu, Lingling; Xu, Dongbin; Yan, Daoliang; Zheng, Bingsong

    2017-04-01

    PILS is a key auxin efflux carrier protein in the auxin signal transduction. A CcPILS gene related to hickory (Carya carthayensis) grafting process was obtained by RACE techniques. The full length of CcPILS gene was1541bp contained a 1263bp length open reading flame (ORF). The CcPILS encoded 294 amino acids with molecular weight of 46 kDa, PI 5.38 and localized at endoplasmic reticulum membrane. The gene contained a central hydrophilic loop separating two hydrophobic domains of about five transmembrane regions each. The gene of CcPILS belonged to Clade III sub-family of PILS and its sequence had high homology with Arabidopsis. Real Time RT-PCR analysis showed that the gene expressions were weakly induced in bud, inflorescence, fruit, leaf and stem, while strongly in root. The expression levels were strongly induced and reached a peak at the third day of grafting in scion and rootstock of hickory, which were 1.45 and 3.45 times higher, respectively, compared to that of control. The results indicated that CcPILS may be involved in regulating the expression of genes related to auxin signal transduction during hickory graft process.

  10. Density of red squirrels and their use of non-native tree species in the Rogów Arboretum

    Directory of Open Access Journals (Sweden)

    Krauze-Gryz Dagny

    2016-03-01

    Full Text Available The aim of the study was to compare the densities of red squirrel (Sciurus vulgaris in the arboretum and a neighbouring forest and to investigate which tree species the squirrels used. The study was conducted in the area of the Rogów Arboretum (53.76 ha and the so-called Zimna Woda and Wilczy Dół forest complexes (altogether 536 ha, all being part of an Experimental Forest Station in Rogów. The density of squirrels in the arboretum and the neighbouring forest was estimated and compared by means of snow tracks on transect routes. Changes in the abundance of squirrels throughout one year as well as their behaviour were determined on the basis of direct observations along transects running through the arboretum. More than half of the area of the arboretum was searched in order to record feeding signs of squirrels. Additionally, trees with bark stripping were recorded.

  11. Seed-borne Botryosphaeria spp. from native Prunus and Podocarpus trees in Ethiopia, with a description of the anamorph Diplodia rosulata sp. nov.

    Science.gov (United States)

    Gure, Abdella; Slippers, Bernard; Stenlid, Jan

    2005-09-01

    Botryosphaeria spp. from seeds of the native afromontane forest tree species, Podocarpus falcatus and Prunus africana, in Ethiopia have been identified. This is achieved by combining anamorph morphological characters and ITS sequence data. From a relatively small sample, four Botryosphaeria spp. were encountered. Two of the species from P. falcatus and the one from P. africana have not been previously described. The two species from P. falcatus were represented by only one isolate each and are not named here. The morphology of their Diplodia and Dothiorella anamorphs is, however, characterised. The anamorph of the other Botryosphaeria sp. from P. africana is described here as Diplodia rosulata sp. nov. Furthermore, B. parva is identified from P. falcatus based on ITS phylogeny. This species is also an important pathogen of various commercially important tree species in Ethiopia and elsewhere. This study highlights the ability of Botryosphaeria spp. to infect seeds and the possibility that they might be distributed in this way. The study also contributes to recent attempts to stabilize the taxonomy of Botryosphaeria anamorphs, especially regarding Diplodia, which is currently in taxonomic disarray.

  12. Chemometric Classification of Different Tree Peony Species Native to China Based on the Assessment of Major Fatty Acids of Seed Oil and Phenotypic Characteristics of the Seeds.

    Science.gov (United States)

    Zhang, Xiao-Xiao; Zhang, Yan-Long; Niu, Li-Xin; Sun, Jia-Yi; Li, Lin-Hao; Zhang, Jing; Li, Jian

    2017-01-01

    In the present study, we quantitatively measured five major fatty acids (FA) in seed oil using gas chromatography/mass spectrometry (GC/MS) and examined four phenotypic characteristics of the seeds from 19 populations from nine wild tree peony species native to China. The results showed that the unsaturated FAs contents were dominant, of which α-linolenic acid (ALA), linoleic acid, and oleic acid (OA) contents ranged from 14.84 to 42.54 g/100 g, 7.33 to 19.66 g/100 g, and 15.07 - 35.31 g/100 g crude oil, respectively. The phenotypic seed characteristics, such as thousand seed weight (244.01 - 1772.91 g), seed volume (91.31 - 1000.79 mm(3) ), weight rate of kernel and coat (1.29 - 3.62) and oil extraction ratio (20.32 - 34.69%), dramatically varied. Based on the contents of the five FAs, the nine species were classified into two groups. The species belonging to subsection Vaginatae were arranged in cluster I and were characterized by high ALA content. Cluster II, consistent with subsection Delavayanae, had a high OA content. From horizontal and vertical perspectives, the natural distribution areas of these two groups were different, reflecting differences in the FA contents and phenotypic seed characteristics. In conclusion, the FAs composition could be used as a chemotaxonomic marker for tree peony species.

  13. Documenting biogeographical patterns of African timber species using herbarium records: a conservation perspective based on native trees from Angola.

    Science.gov (United States)

    Romeiras, Maria M; Figueira, Rui; Duarte, Maria Cristina; Beja, Pedro; Darbyshire, Iain

    2014-01-01

    In many tropical regions the development of informed conservation strategies is hindered by a dearth of biodiversity information. Biological collections can help to overcome this problem, by providing baseline information to guide research and conservation efforts. This study focuses on the timber trees of Angola, combining herbarium (2670 records) and bibliographic data to identify the main timber species, document biogeographic patterns and identify conservation priorities. The study recognized 18 key species, most of which are threatened or near-threatened globally, or lack formal conservation assessments. Biogeographical analysis reveals three groups of species associated with the enclave of Cabinda and northwest Angola, which occur primarily in Guineo-Congolian rainforests, and evergreen forests and woodlands. The fourth group is widespread across the country, and is mostly associated with dry forests. There is little correspondence between the spatial pattern of species groups and the ecoregions adopted by WWF, suggesting that these may not provide an adequate basis for conservation planning for Angolan timber trees. Eight of the species evaluated should be given high conservation priority since they are of global conservation concern, they have very restricted distributions in Angola, their historical collection localities are largely outside protected areas and they may be under increasing logging pressure. High conservation priority was also attributed to another three species that have a large proportion of their global range concentrated in Angola and that occur in dry forests where deforestation rates are high. Our results suggest that timber tree species in Angola may be under increasing risk, thus calling for efforts to promote their conservation and sustainable exploitation. The study also highlights the importance of studying historic herbarium collections in poorly explored regions of the tropics, though new field surveys remain a priority to

  14. Classification of non native tree species in Adda Park (Italy) through multispectral and multitemporal surveys from UAV

    Science.gov (United States)

    Pinto, Livio; Sona, Giovanna; Biffi, Andrea; Dosso, Paolo; Passoni, Daniele; Baracani, Matteo

    2014-05-01

    The project ITACA (Innovation, Technologies, Actions to Contrast Alloctonous species) rises from the need of protecting natural habitats in parks where native vegetation is threaten by the always increasing spread of alloctonous species. Starting from preliminary results obtained in previous experimental studies performed inside Adda Park (Lombardy Region, Northern Italy) the aim of the project is a further development and optimization of some tested techniques and procedures. In the frame of ITACA project, that involves Politecnico di Milano and some local enterprises, 11 separate areas of the Adda Park, globally covering 50 hectars, will be surveyed with UAV-borne multispectral sensors through different seasons (summer, autumn and spring). The summer and autumn flights have already been realized by the fixed wing UAV Sensefly SwingletCAM mounted with a Canon Ixus 220HS, producing real color images (RGB), and an identical camera, modified to produce false color images (NIR-RG). The 'multisensor-multitemporal' flights have been planned with high longitudinal and transversal overlaps, always in the range 60% to 80%, and a GSD of around 4 cm. Presignalized artificial points or natural elements have been surveyed on the ground by GPS RTK Trimble 5700, making use a Network GPS ervice (NRTK). For each survey two flights have been realized, one with the standard camera, and the second one with the NIR-modified one, with the double purpose of: - producing a multispectral orthomosaic, formed by the four bands NIR-R-G-B, coregistered. - increasing the coverage of the area, yielding in the block adjustment phase a more robust solution and a higher metric accuracy of digital products (digital orthomosaics). The first two flights have been scheduled taking into account information on the phenology of the species under observation (both native or invasive) given by expert botanists involved in the project. The first set of acquisition, originally planned for the first half of

  15. Development of SSR Markers in Hickory (Carya cathayensis Sarg.) and Their Transferability to Other Species of Carya.

    Science.gov (United States)

    Li, Juan; Zeng, Yanru; Shen, Dengfeng; Xia, Guohua; Huang, Yinzhi; Huang, Youjun; Chang, Jun; Huang, Jianqin; Wang, Zhengjia

    2014-10-01

    Hickory (Carya cathayensis Sarg.), an important nut-producing species in Southeastern China, has high economic value, but so far there has been no cultivar bred under species although it is mostly propagated by seeding and some elite individuals have been found. It has been found recently that this species has a certain rate of apomixis and poor knowledge of its genetic background has influenced development of a feasible breeding strategy. Here in this paper we first release SSR (Simple sequence repeat) markers developed in this species and their transferability to other three species of the same genus, Carya. A total of 311 pairs of SSR primers in hickory were developed based on sequenced cDNAs of a fruit development-associated cDNA library and RNA-seq data of developing female floral buds and could be used to distinguish hickory, C. hunanensis Cheng et R. H. Chang ex R. H. Chang et Lu, C. illinoensis K. Koch (pecan) and C. dabieshanensis M. C. Liu et Z. J. Li, but they were monomorphic in both hickory and C. hunanensis although multi-alleles have been identified in all the four species. There is a transferability rate of 63.02% observed between hickory and pecan and the markers can be applied to study genetic diversity of accessions in pecan. When used in C. dabieshanensis, it was revealed that C. dabieshanensis had the number of alleles per locus ranging from 2 to 4, observed heterozygosity from 0 to 0.6667 and expected heterozygosity from 0.333 to 0.8667, respectively, which supports the existence of C. dabieshanensis as a separate species different from hickory and indicates that there is potential for selection and breeding in this species.

  16. Estimating Invasion Success by Non-Native Trees in a National Park Combining WorldView-2 Very High Resolution Satellite Data and Species Distribution Models

    Directory of Open Access Journals (Sweden)

    Antonio T. Monteiro

    2017-01-01

    Full Text Available Invasion by non-native tree species is an environmental and societal challenge requiring predictive tools to assess invasion dynamics. The frequent scale mismatch between such tools and on-ground conservation is currently limiting invasion management. This study aimed to reduce these scale mismatches, assess the success of non-native tree invasion and determine the environmental factors associated to it. A hierarchical scaling approach combining species distribution models (SDMs and satellite mapping at very high resolution (VHR was developed to assess invasion by Acacia dealbata in Peneda-Gerês National Park, the only national park in Portugal. SDMs were first used to predict the climatically suitable areas for A. dealdata and satellite mapping with the random-forests classifier was then applied to WorldView-2 very-high resolution imagery to determine whether A. dealdata had actually colonized the predicted areas (invasion success. Environmental attributes (topographic, disturbance and canopy-related differing between invaded and non-invaded vegetated areas were then analyzed. The SDM results indicated that most (67% of the study area was climatically suitable for A. dealbata invasion. The onset of invasion was documented to 1905 and satellite mapping highlighted that 12.6% of study area was colonized. However, this species had only colonized 62.5% of the maximum potential range, although was registered within 55.6% of grid cells that were considerable unsuitable. Across these areas, the specific success rate of invasion was mostly below 40%, indicating that A. dealbata invasion was not dominant and effective management may still be possible. Environmental attributes related to topography (slope, canopy (normalized difference vegetation index (ndvi, land surface albedo and disturbance (historical burnt area differed between invaded and non-invaded vegetated area, suggesting that landscape attributes may alter at specific locations with Acacia

  17. Integrating active restoration with environmental flows to improve native riparian tree establishment in the Colorado River Delta

    Science.gov (United States)

    Schlatter, Karen; Grabau, Matthew R.; Shafroth, Patrick B.; Zamora-Arroyo, Francisco

    2017-01-01

    Drastic alterations to river hydrology, land use change, and the spread of the nonnative shrub, tamarisk (Tamarix spp.), have led to the degradation of riparian habitat in the Colorado River Delta in Mexico. Delivery of environmental flows to promote native cottonwood (Populus spp.) and willow (Salix spp.) recruitment in human-impacted riparian systems can be unsuccessful due to flow-magnitude constraints and altered abiotic–biotic feedbacks. In 2014, an experimental pulse flow of water was delivered to the Colorado River in Mexico as part of the U.S.-Mexico binational agreement, Minute 319. We conducted a field experiment to assess the effects of vegetation removal, seed augmentation, and environmental flows, separately and in combination, on germination and first-year seedling establishment of cottonwood, willow, and tamarisk at five replicate sites along 5 river km. The relatively low-magnitude flow deliveries did not substantively restore natural fluvial processes of erosion, sediment deposition, and vegetation scour, but did provide wetted surface soils, shallow groundwater, and low soil salinity. Cottonwood and willow only established in wetted, cleared treatments, and establishment was variable in these treatments due to variable site conditions and inundation duration and timing. Wetted soils, bare surface availability, soil salinity, and seed availability were significant factors contributing to successful cottonwood and willow germination, while soil salinity and texture affected seedling persistence over the growing season. Tamarisk germinated and persisted in a wider range of environmental conditions than cottonwood and willow, including in un-cleared treatment areas. Our results suggest that site management can increase cottonwood and willow recruitment success from low-magnitude environmental flow events, an approach that can be applied in other portions of the Delta and to other human-impacted riparian systems across the world with similar

  18. Phytophthora niederhauserii sp. nov., a polyphagous species associated with ornamentals, fruit trees and native plants in 13 countries.

    Science.gov (United States)

    Abad, Z Gloria; Abad, Jorge A; Cacciola, Santa Olga; Pane, Antonella; Faedda, Roberto; Moralejo, Eduardo; Pérez-Sierra, Ana; Abad-Campos, Paloma; Alvarez-Bernaola, Luis A; Bakonyi, József; Józsa, András; Herrero, Maria Luz; Burgess, Treena I; Cunnington, James H; Smith, Ian W; Balci, Yilmaz; Blomquist, Cheryl; Henricot, Béatrice; Denton, Geoffrey; Spies, Chris; Mcleod, Adele; Belbahri, Lassaad; Cooke, David; Kageyama, Koji; Uematsu, Seiji; Kurbetli, Ilker; Değirmenci, Kemal

    2014-01-01

    A non-papillate, heterothallic Phytophthora species first isolated in 2001 and subsequently from symptomatic roots, crowns and stems of 33 plant species in 25 unrelated botanical families from 13 countries is formally described here as a new species. Symptoms on various hosts included crown and stem rot, chlorosis, wilting, leaf blight, cankers and gumming. This species was isolated from Australia, Hungary, Israel, Italy, Japan, the Netherlands, Norway, South Africa, Spain, Taiwan, Turkey, the United Kingdom and United States in association with shrubs and herbaceous ornamentals grown mainly in greenhouses. The most prevalent hosts are English ivy (Hedera helix) and Cistus (Cistus salvifolius). The association of the species with acorn banksia (Banksia prionotes) plants in natural ecosystems in Australia, in affected vineyards (Vitis vinifera) in South Africa and almond (Prunus dulcis) trees in Spain and Turkey in addition to infection of shrubs and herbaceous ornamentals in a broad range of unrelated families are a sign of a wide ecological adaptation of the species and its potential threat to agricultural and natural ecosystems. The morphology of the persistent non-papillate ellipsoid sporangia, unique toruloid lobate hyphal swellings and amphigynous antheridia does not match any of the described species. Phylogenetic analysis based on sequences of the ITS rDNA, EF-1α, and β-tub supported that this organism is a hitherto unknown species. It is closely related to species in ITS clade 7b with the most closely related species being P. sojae. The name Phytophthora niederhauserii has been used in previous studies without the formal description of the holotype. This name is validated in this manuscript with the formal description of Phytophthora niederhauserii Z.G. Abad et J.A. Abad, sp. nov. The name is coined to honor Dr John S. Niederhauser, a notable plant pathologist and the 1990 World Food Prize laureate. © 2014 by The Mycological Society of America.

  19. After 25 years, what does the Pennsylvania Regeneration Study tell us about oak/hickory forests under stress?

    Science.gov (United States)

    William H. McWilliams; James A. Westfall; Patrick H. Brose; Shawn L. Lehman; Randall S. Morin; Todd E. Ristau; Alejandro A. Royo; Susan L. Stout

    2017-01-01

    The Pennsylvania Regeneration Study was initiated in 1989 because of concerns about a long history of stress on oak/hickory (Quercus/Carya) forests from herbivory and other factors. The study, which addresses the need for landscape-level information about regeneration quality and abundance, comprises a suite of regeneration indicator measurements...

  20. Moisture changes in oak and hickory fuel chips on roofed and unroofed Louisiana air-drying grounds as affected by pile depth and turning of chips

    Energy Technology Data Exchange (ETDEWEB)

    Koch, P.

    1983-06-01

    Freshly cut whole-tree hickory chips had lower moisture content (MC) initially and dried more rapidly than those of southern red oak. Such chips spread during April, 1981 in roofed trays did not dry to 20 percent MC, ovendry-weight basis, faster than those spread in October, 1980. In roofed trays, unturned chips spread 4 inches deep generally dried more rapidly than if spread 8 or 12 inches deep. Times to 20 percent average MC for layers 4, 8, and 12 inches deep were 78 to 94, 79 to 136, and 81 to 150 days, respectively. Twelve-inch-thick layers of southern red oak chips in unroofed trays increased in MC with time, but less so if turned weekly. Twelve-inch-thick layers of southern red oak chips in roofed trays dried considerably faster if turned. Even when in roofed trays and turned weekly, however, 87 days of drying were required to reach 31 percent average MC, and 151 days to reach 29 percent MC.

  1. Mobility, bioavailability and speciation of potentially toxic metals in a sludges-polluted agricultural soil under remediation with poplar trees and native grasses

    Science.gov (United States)

    Adamo, Paola; Agrelli, Diana; Giandonato Caporale, Antonio; Fiorentino, Nunzio; Duri, Luigi; Fagnano, Massimo

    2017-04-01

    For the assessment of health and environmental risks deriving from the pollution of agricultural soils, it is critical the identification and the chemical characterization of the contaminants and of the polluted soil, because these characteristics influence the mobility and bioavailability of the contaminants and therefore their transfer from soil to other environmental compartments and to the food chain. In addition, these information are crucial to assess the effectiveness of remediation and management actions. Our study site is an agricultural area of 6 ha, currently under sequestration, located in the province of Naples (Campania Region), interested by past illegal dumping of industrial wastes, mainly tannery sludges. In the area, after an intense phase of soil characterization by geophysical and geochemical surveys, it is realizing an environmental remediation project with poplar trees and native grass species, also with the aim of analyzing the possible absorption and accumulation of contaminants in the vegetables. The soil sampling was carried out by taking punctual samples of soil according to a grid of 20 x 20 m, at three depths (0-20; 30-60; 70-90 cm). Furthermore, materials attributable to the buried sludges were sampled from pedological profiles opened in the field. All the samples were analyzed for the content of potentially toxic metals and of heavy hydrocarbons (C>12). On selected samples were determined the main chemical and physical characteristics, mobile and bioavailable fractions of the major metal contaminants and their distribution in the soil geochemical fractions, with water (solid/liquid partition coefficient), 1 M NH4NO3 and 0.05 M EDTA pH 7 extractions, and EU-BCR sequential fractionation. The data showed a significant, widespread and disorderly contamination by chromium, zinc and heavy hydrocarbons (up to values of: 4500 mg/kg for Cr, 1850 mg/kg for Zn 1250 mg/kg for hydrocarbons C>12). In certain sub-areas it has also been observed a

  2. 深圳市羊台山森林公园优良乡土阔叶树种选择技术研究%Study on Selection of Native Broadleaf Tree Species in Yangtaishan Forest Park in Shenzhen

    Institute of Scientific and Technical Information of China (English)

    王祥; 王海军; 王中激; 连辉明; 黄钰辉; 曾令海

    2012-01-01

    对广东省深圳市羊台山森林公园内的1块林分改造试验林和1块新造林的树种生长情况进行调查,分析不同树种生长的差异,以此为羊台山地区林分改造和新造林的树种选择提供理论依据.分析结果表明:林分改造试验林中选出14个树种,其林木生长较佳;新造林中紫荆、深山含笑、黄花风铃木、降香黄檀、阴香、土沉香和假苹婆7个树种表现优良.选出的21个树种按用途分为9种乡土生态阔叶树,8种景观树种,5种特色外来树种及4种珍贵树种.在羊台山进行森林公园林分改造或新造林时,树种选择应以乡土阔叶树为骨干,适当搭配景观树种,引进少量的珍贵树种和有特色的外来树种,这对于提升林分质量,改善森林景观,提升森林的文化内涵具有重要意义,同时为类似森林公园的林分改造和造林树种选择提供借鉴和参考.%The growth of tree in two plots of test stands ( a reconstruction and a new afforestation) in Yangtaishan forest park were investigated and analyzed. This paper is useful for selection of native broadleaf tree species in forest reconstruction in Yangtaishan forest park. In the reconstruction stand, 14 tree species grew well and were selected. In the new afforestation stand, 7 tree species grew well, including Bauhinia variegata, Michelia maudi-ae, Tabebuia chrysantha, Dalbergia odorifera, Cinnamomum burmannii, Aquilaria sinensis and Sterculia lanceola-ta. There are 9 species of native broadleaf trees, 8 species of landscape trees, 5 special exotic species and 4 precious species among the total 21 selected species. For tree selection in reconstruction and afforestation stand in forest park, native broadleaf species as the majority, collocation of landscape trees and a few precious species and exotic species should be the ideal mode. This mode is very important for improving stand quality, landscape and culture. This study is useful for improving ecological

  3. Chinese tallow trees (Triadica sebifera from the invasive range outperform those from the native range with an active soil community or phosphorus fertilization.

    Directory of Open Access Journals (Sweden)

    Ling Zhang

    Full Text Available Two mechanisms that have been proposed to explain success of invasive plants are unusual biotic interactions, such as enemy release or enhanced mutualisms, and increased resource availability. However, while these mechanisms are usually considered separately, both may be involved in successful invasions. Biotic interactions may be positive or negative and may interact with nutritional resources in determining invasion success. In addition, the effects of different nutrients on invasions may vary. Finally, genetic variation in traits between populations located in introduced versus native ranges may be important for biotic interactions and/or resource use. Here, we investigated the roles of soil biota, resource availability, and plant genetic variation using seedlings of Triadica sebifera in an experiment in the native range (China. We manipulated nitrogen (control or 4 g/m(2, phosphorus (control or 0.5 g/m(2, soil biota (untreated or sterilized field soil, and plant origin (4 populations from the invasive range, 4 populations from the native range in a full factorial experiment. Phosphorus addition increased root, stem, and leaf masses. Leaf mass and height growth depended on population origin and soil sterilization. Invasive populations had higher leaf mass and growth rates than native populations did in fresh soil but they had lower, comparable leaf mass and growth rates in sterilized soil. Invasive populations had higher growth rates with phosphorus addition but native ones did not. Soil sterilization decreased specific leaf area in both native and exotic populations. Negative effects of soil sterilization suggest that soil pathogens may not be as important as soil mutualists for T. sebifera performance. Moreover, interactive effects of sterilization and origin suggest that invasive T. sebifera may have evolved more beneficial relationships with the soil biota. Overall, seedlings from the invasive range outperformed those from the native

  4. Chinese tallow trees (Triadica sebifera) from the invasive range outperform those from the native range with an active soil community or phosphorus fertilization.

    Science.gov (United States)

    Zhang, Ling; Zhang, Yaojun; Wang, Hong; Zou, Jianwen; Siemann, Evan

    2013-01-01

    Two mechanisms that have been proposed to explain success of invasive plants are unusual biotic interactions, such as enemy release or enhanced mutualisms, and increased resource availability. However, while these mechanisms are usually considered separately, both may be involved in successful invasions. Biotic interactions may be positive or negative and may interact with nutritional resources in determining invasion success. In addition, the effects of different nutrients on invasions may vary. Finally, genetic variation in traits between populations located in introduced versus native ranges may be important for biotic interactions and/or resource use. Here, we investigated the roles of soil biota, resource availability, and plant genetic variation using seedlings of Triadica sebifera in an experiment in the native range (China). We manipulated nitrogen (control or 4 g/m(2)), phosphorus (control or 0.5 g/m(2)), soil biota (untreated or sterilized field soil), and plant origin (4 populations from the invasive range, 4 populations from the native range) in a full factorial experiment. Phosphorus addition increased root, stem, and leaf masses. Leaf mass and height growth depended on population origin and soil sterilization. Invasive populations had higher leaf mass and growth rates than native populations did in fresh soil but they had lower, comparable leaf mass and growth rates in sterilized soil. Invasive populations had higher growth rates with phosphorus addition but native ones did not. Soil sterilization decreased specific leaf area in both native and exotic populations. Negative effects of soil sterilization suggest that soil pathogens may not be as important as soil mutualists for T. sebifera performance. Moreover, interactive effects of sterilization and origin suggest that invasive T. sebifera may have evolved more beneficial relationships with the soil biota. Overall, seedlings from the invasive range outperformed those from the native range, however

  5. Genetic signatures of variation in population size in a native fungal pathogen after the recent intensive plantation of its host tree

    NARCIS (Netherlands)

    Labbé, Frédéric; Fontaine, Michael Christophe; Robin, Cécile; Dutech, Cyril

    2017-01-01

    Historical fluctuations in forests’ distribution driven by past climate changes and anthropogenic activities can have large impacts on the demographic history of pathogens that have a long co-evolution history with these host trees. Using a population genetic approach, we investigated that

  6. Initial Growth Effect of Mixed Forests with Eucalypt and Two Native Broadleaved Tree Species of Guangxi%桉树与乡土阔叶树种混交林的初期生长效应

    Institute of Scientific and Technical Information of China (English)

    姚瑞玲; 项东云; 陈健波

    2012-01-01

    以红锥(Castanopsis hystrix)、米老排(Mytilaria laosensis)2种广西乡土阔叶树种为混交树种,对不同混交模式下桉树与红锥、米老排的林木生长情况进行了分析。研究结果表明:在桉树与米老排(3∶1)混交模式下,桉树树高、胸径生长量明显高于桉树纯林。而混交模式下,红锥生长量增加,而米老排生长量降低。初步认为,混交能促进桉树生长,但最佳混交造林模式因混交树种而异。%Growth of eucalypt,Castanopsis hystrix and Mytilaria laisensis in different patterns of mixed forests was analyzed using two native broadleaved tree species,C.hystrix and M.laosensis of Guangxi as mixed tree species.The results showed that tree height and DBH of eucalypt from mixed plantations of eucalypt and C.hystrix(3∶1) were significantly greater than that from pure eucalypt plantations.The growth of C.hystrix increased,while that of M.laosensis decreased in the condition of mixed planting.In preliminary conclusion, mixed planting was able to promote the growth of eucalypt,but the optimal pattern of mixed planting depended on mixed tree species.

  7. Physically (CO2) activated hydrochars from hickory and peanut hull: preparation, characterization, and sorption of methylene blue, lead, copper, and cadmium

    Science.gov (United States)

    The effects of carbon dioxide activation temperature (600-900 degree Celsius °C) and time (1 and 2 h) on the physicochemical and sorptive characteristics of hickory and peanut hull hydrochars were investigated. The extent of burn-off increased with increasing activation times and temperatures, and r...

  8. Contrasting responses to drought of forest floor CO2 efflux in a loblolly pine plantation and a nearby Oak-Hickory forest

    Science.gov (United States)

    S. Palmroth; Chris A. Maier; Heather R. McCarthy; A. C. Oishi; H. S. Kim; Kurt H. Johnsen; Gabrial G. Katul; Ram Oren

    2005-01-01

    Forest floor C02 efflux (Fff) depends on vegetation type, climate, and soil physical properties. We assessed the effects of biological factors on Fff by comparing a maturing pine plantation (PP) and a nearby mature Oak-Hickory-type hardwood forest (HW). Fff was measured...

  9. Growth and Influencing Factors of Three Native Tree Species in Coastal Casuarina equisetifolia Plantation%滨海木麻黄林下3种乡土树种苗木的生长及其影响因素

    Institute of Scientific and Technical Information of China (English)

    姚宝琪; 刘强; 蔡梓; 王孝杉

    2011-01-01

    [ Objective] The aim was to study the growth and environment factors of three native tree species ( Thespesia lampas, Calophyllum inophyllum and Hernandia sonora) in Hainan in coastal Casuarina equisetifolia plantation. [ Method ] The coastal sandy soil was treated by adding wood chips, bagasse and the control without adding anything in the plant pits. The growth of three native tree species planted for one year was analyzed. [ Result ] ① One year later, the survival rate showed an order of T. lampas > H. sonora > C. inophyllum;the net increase of basal diameter showed an order of H. sonora > T. lampas > C. inophyllum;while the net increase of plant height showed an order of T. lampas > C.inophyllum > H. sonora. The difference of survival rate between T. lampas and C. inophyllum was extremely significant, the difference of survival rate between H. sonora and C. inophyllum was significant, but the survival rate between T. lampas and H. sonora showed no significant difference. The difference on net growth of plant height among T. lampas, C. inophyllum and H. sonora was extremely significant, and the different on the net growth of basal diameter between T. lampas and C. inophyllum was significant. ② Among different soil treatments,the survival rate of three native tree species in the treatment by adding wood chips, bagasse were higher than the treatment without adding anything, and the difference of survival rate of T. lampas between the treatment by adding wood chips, bagasse and the treatment without adding anything was extremely significant, but the treatment by adding wood chips and bagasse had not significant difference. ③ The growth of three native tree species showed some correlation with environment factors ( | r |>0.3). The survival rate of T. lampas showed higher correlation with soil pH value and soil moisture, and the basal diameter and height of T. lampas showed some correlation with soil pH value and soil temperature. The survival

  10. Stomatal ozone flux and visible leaf injury in native juvenile trees of Fagus sylvatica L.: a field study from the Jizerske hory Mts., the Czech Republic.

    Science.gov (United States)

    Vlasáková-Matoušková, Leona; Hůnová, Iva

    2015-07-01

    The study was carried out at six sites in the Jizerskehory Mts. in the north of the Czech Republic. At all these sites, ranging in altitude between 460 and 962 m a. s. l., and during the period from June to September in 2008, O3 concentrations and environmental parameters important for accumulated stomatal O3 flux (AFst) into Fagus sylvatica leaves were measured. At five sites, visible injury on Fagus sylvatica L. juvenile tree leaves was observed. A combination of actual O3 levels in the Jizerkehory Mts. and environmental conditions, though relative air humidity and air temperature significantly limited stomatal conductance, has been sufficient enough to cause O3 uptake exceeding the critical level (CL) for forest ecosystems. The AFst values ranged between 13.4 and 22.3 mmol O3 m(-2). The CL for the accumulated stomatal flux of O3 above a flux threshold 1.6 nmol m(-2) s(-1) (AFst1.6) was exceeded at all sites from ca 45 to 270% (160% on average). The CL of 5 ppm h(-1) for AOT40 (accumulated O3 exposure above threshold of 40 ppb) was exceeded at four sites. The relationship between visible injury on O3 indices was found. The conclusions based on AOT40 and AFSt are not the same. AFSt has been determined as better predictor of visible injury than AOT40.

  11. Gas exchange, growth, and chemical parameters in a native Atlantic forest tree species in polluted areas of Cubatão, Brazil.

    Science.gov (United States)

    Moraes, R M; Delitti, W B C; Moraes, J A P V

    2003-03-01

    The Atlantic forest species near the industrial complex of Cubatão, Brazil have been subjected to heavy air pollution for decades. In this study, we used some physiological parameters (gas exchange, growth and chemical contents) to biomonitor the effects of air pollution on Tibouchina pulchra, one of the most common tree species in this forest. Under standardized conditions, saplings were exposed to the environment from April to July and from July to September of 1998, at three different sites in the vicinity of the industrial complex: the Valley of Pilões River (VP), the control area; the Valley of Mogi River (VM), near fertilizer, metallurgical, and cement industries sustaining high concentrations of fluorides, N and S oxides, and particulate materials; and Caminho do Mar (CM), near petrochemical industries under N and S oxides, photooxidants, and organic compounds. Plants exposed to CM and VM conditions presented visible injuries, reductions in net photosynthesis, growth parameters, and ascorbate concentrations, and increased F, N, and S foliar concentrations. These results indicate that the environmental conditions around these industries are still harmful to plants.

  12. Assessing redox potential of a native tree from the Brazilian Atlantic Rainforest: a successful evaluation of oxidative stress associated to a new power generation source of an oil refinery.

    Science.gov (United States)

    Esposito, Marisia Pannia; Pedroso, Andrea Nunes Vaz; Domingos, Marisa

    2016-04-15

    The antioxidant responses in saplings of Tibouchina pulchra (a native tree from the Brazilian Atlantic Rainforest) exposed around an oil refinery in the city of Cubatão (SE Brazil), varied during the exchange of its power generation source, from boilers fueled with oil to a thermoelectric fueled with natural gas. The redox potential changed in response to an interaction of air pollution and meteorological parameters, indicating that the pro-oxidant/antioxidant balance was not reached after the exchange of the power generation system. The gain in environmental quality in the region was not achieved as expected due the technological modernization, at least relative to oxidative stressors. These conclusions were based on results of analyses of enzymatic antioxidants: superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT), glutathione reductase (GR); non-enzymatic antioxidants: reduced, oxidized and total ascorbic acid (AsA, DHA, totAA) and glutathione (GSH, GSSG, totG), their redox state (AsA/totAA and GSH/totG) and an indicator of lipid peroxidation (MDA). We also applied exploratory multivariate statistics in order to verify if the temporal sequence of changes in the plant redox capacity coincided with changes in the profile of air pollution, climatic conditions or with their interactions and if the environmental benefits that would supposedly be promoted by the mentioned exchange of power generation system were achieved in the region.

  13. Archeological Survey of Selected Fish and Wildlife Management Areas at Pomme de Terre and Stockton Lakes, Dade, Hickory, and Polk Counties, Missouri

    Science.gov (United States)

    1989-01-01

    Selected Fish and Wildlife Management Areas at Pomme de Terre and Stockton Lakes, Dade, Hickory, and Polk Counties, Missouri Contract No. DACW41-81-C...Jackson _________________________56 1989 907 0J) O . ARCHEOLOGICAL SURVEY OF SELECTED FISH AND WILDLIFE MANAGEMENT AREAS AT POMME DE TERRE AND...NO. NO. ACCESSION NO. 11. TITLE (Include Securrty Classification) Archeological Survey of Selected Fish and Wildlife Management Areas at Pomme de Terre

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

    Directory of Open Access Journals (Sweden)

    CHRISTOPHER H. LUSK

    2001-09-01

    -central Chile to exotic tree plantations. However, little is known about the effects of these wholesale landuse changes on ecosystem properties and processes, with the notable exception of studies of site water balance. In this brief communication, we present the results of a comparative study of decomposition of leaf litter of Pinus radiata and three common native tree species, beneath exotic and native woody vegetation in south-central Chile. We aimed to assess the nutrient cycling implications of substitution or invasion of native vegetation by P. radiata. Litter samples of the four species were incubated in both environments, registering the percentage of dry weight loss after two and six months. Decomposition rates of all species were much faster during the first two months of incubation than during the four subsequent months. At both dates there were significant differences between species and between sites, with faster decomposition of all species beneath P. radiata. There was no evidence of interaction between species and site. After six months, species rank order for the percentage of weight loss was Nothofagus obliqua > P. radiata > Peumus boldus > Cryptocarya alba. Interspecific variation in decomposition rates was more closely correlated with specific leaf area than with litter nitrogen content. Given that litter of P. radiata decomposed slower than that of the deciduous N. obliqua, but faster than the sclerophyll evergreens, the consequences of substitution or invasion for decomposition processes are likely to depend on the composition of the native vegetation in question

  15. Seletividade dos herbicidas setoxidim, isoxaflutol e bentazon a espécies arbóreas nativas Selectivity of the herbicides sethoxydim, isoxaflutole and bentazon on native tree species

    Directory of Open Access Journals (Sweden)

    Pedro Henrique Santin Brancalion

    2009-03-01

    Full Text Available O objetivo deste trabalho foi avaliar a sensibilidade de espécies nativas usadas em recuperação de áreas degradadas aos herbicidas setoxidim, isoxaflutol e bentazon. As espécies estudadas foram Senna multijuga, Guazuma ulmifolia e Croton urucurana. Os tratamentos de herbicida consistiram de uma testemunha (sem aplicação e aplicação de um quarto, metade, uma vez, duas vezes e quatro vezes a dose recomendada. As doses recomendadas são 184 g ha-1 de setoxidim, 37,5 g ha-1 de isoxaflutol e 720 g ha-1 de bentazon. Avaliaram-se os sintomas de fitotoxicidade, crescimento em altura, acréscimo no número de folhas e massa de matéria seca de folhas. Em outros experimentos, as doses recomendadas dos mesmos herbicidas foram aplicadas em outras 22 espécies arbóreas nativas, nas quais avaliou-se a massa de matéria seca de folhas. O delineamento experimental dos experimentos foi o inteiramente casualizado, com quatro repetições. Cada parcela experimental se constituiu de uma muda em estádio inicial de desenvolvimento. Os herbicidas não provocaram a morte das mudas, embora todas tenham apresentado sintomas de fitotoxicidade. A aplicação de isoxaflutol reduziu a massa de matéria seca das folhas em 20% das espécies, a aplicação de bentazon, em uma espécie, e a aplicação de setoxidim não reduziu a massa de matéria seca das folhas de nenhuma espécie.The objective of this work was to evaluate the sensitivity of native tree species used in the recovery of degraded land to the herbicides sethoxydim, isoxaflutole and bentazon. The species studied were Senna multijuga, Guazuma ulmifolia and Croton urucurana, and the treatment applied comprised one control sample (no herbicides were applied and the application of the herbicides at one fourth, half, one, two and fourfold the recommended dose (sethoxydim: 184 g ha-1, isoxaflutole: 37.5 g ha-1, bentazon: 720 g ha-1. Phytotoxicity symptoms, growth in length, increase in leaf number, and leaf

  16. Atlas of United States Trees, Volume 2: Alaska Trees and Common Shrubs.

    Science.gov (United States)

    Viereck, Leslie A.; Little, Elbert L., Jr.

    This volume is the second in a series of atlases describing the natural distribution or range of native tree species in the United States. The 82 species maps include 32 of trees in Alaska, 6 of shrubs rarely reaching tree size, and 44 more of common shrubs. More than 20 additional maps summarize environmental factors and furnish general…

  17. Sobrevivência e crescimento inicial em campo de espécies florestais nativas do Brasil Central indicadas para sistemas silvipastoris Survival and initial growing of native tree seedlings in pastures of Central Brazil

    Directory of Open Access Journals (Sweden)

    Alex Melotto

    2009-06-01

    Full Text Available Objetivou-se, neste estudo, avaliar o índice de sobrevivência e o crescimento inicial de 11 espécies arbóreas nativas do Brasil central, plantadas diretamente em pastagem de Brachiaria brizantha cv. Marandu, em Campo Grande, MS. O solo foi classificado como Latossolo Vermelho, argiloso e distrófico, onde foi implantado um arboreto com 16 parcelas compostas, cada uma, por um indivíduo das 11 espécies selecionadas, em blocos casualizados (DBC com quatro repetições. Os espaçamentos em campo foram de 10,0 x 4,0 m. Houve diferenças (P=0,05 entre as médias de sobrevivência das espécies estudadas, indicando influência do estágio sucessional da espécie. Os maiores índices foram de ocorrência nas seguintes espécies: ipê (Tabebuia impetiginosa, caroba (Jacaranda decurrens e da aroeira (Myracrodruon urundeuva. As mais altas taxas de crescimento relativo nos 12 meses avaliados foram alcançadas por chico-magro (Guazuma ulmifolia, caroba (J. cuspidifolia e canafístula (Peltophorum dubium. Houve diferença estatística (P=0,05 entre o crescimento das espécies de estágios sucessionais iniciais (pioneiras e as de estádios tardios, e tais diferenças acentuaram-se com a idade e com a estação chuvosa. Três espécies que obtiveram as melhores combinações dos acréscimos em altura, diâmetro do colo e sobrevivência foram aptas para o cultivo em pastagens na região dos Cerrados: chico-magro (G. ulmifolia, caroba (J. cuspidifolias e canafístula (P. dubium, sendo todas três de estágios sucessionais iniciais.This work aimed to evaluate the rate of survival and the initial development of eleven native tree species established in existing pastures of Brachiaria brizantha at the Beef Cattle Center (Campo Grande, MS. The soil is a dystrophic clay Dark- Red Latosoil. The seedlings were planted in 16 rows, with 10 m between rows and 4 m between plants in a row. It was used a completely randomized design with four replicates. Each row

  18. SURVIVAL AND GROWTH OF NATIVE TREE SEEDLINGS IN SECONDARY FOREST OF HONG KONG%香港乡土树种幼苗在次生林下生长的研究

    Institute of Scientific and Technical Information of China (English)

    庄雪影; Richa.,C

    2000-01-01

    The seedling survival and growth of 21 native tree species were studied by transplanting into two natural forest sites and an open site for approximately 22 months during June-August ]989 and April-October 1991. The results showed that the seedlings of most species had some tolerance to shading and could survive in forests. Only a few species showed extreme tolerance or intolerance to shade. The seedlings of most pioneer species died directly from shading or insect damage and pathogens in forests. The extremely shadeintolerant species in the study were Pinus massoniana, Sapium discolor, and Trema tomentosa.These species with a typical syndrome of pioneer characters do not play an important role in secondary succession in Hong Kong. The major components in current secondary forest,such as Machilus chekiangensis and Gordonia axillaris, have mixed and intermediate characters,which may be an adaptation to the soil degradation caused by centuries of fire and erosion.Bird-dispersed species play an important role in secondary forest of Hong Kong. Research and application of the bird-dispersed woody flora must be enhanced. Some hypotheses on the current floristic succession are briefly discussed.%通过苗木移植试验,测定了21种香港乡土树种在次生林下的成活率及生长状况.结果表明,大多数种类的幼苗具有一定的耐荫性,可在林下生长;只有极少数种类表现出极耐荫或极不耐荫,导致林下先锋树种幼苗死亡率高的主要原因是荫蔽或因荫蔽而生长不良受病虫害致死.在香港次生林演替中占优势的种类通常具有生长快、稍耐荫,或生长稍慢但耐胁迫等特点.这是对香港退化土地长期适应的结果.鸟播植物在香港次生林中占有重要地位,建议加强鸟播树种生态学特性的研究及其在植树造林中应用.结合本实验结果,对一些现代植物群落演替假说进行了简要的讨论.

  19. Native bees mediate long-distance pollen dispersal in a shade coffee landscape mosaic.

    Science.gov (United States)

    Jha, Shalene; Dick, Christopher W

    2010-08-01

    Coffee farms are often embedded within a mosaic of agriculture and forest fragments in the world's most biologically diverse tropical regions. Although shade coffee farms can potentially support native pollinator communities, the degree to which these pollinators facilitate gene flow for native trees is unknown. We examined the role of native bees as vectors of gene flow for a reproductively specialized native tree, Miconia affinis, in a shade coffee and remnant forest landscape mosaic. We demonstrate extensive cross-habitat gene flow by native bees, with pollination events spanning more than 1,800 m. Pollen was carried twice as far within shade coffee habitat as in nearby forest, and trees growing within shade coffee farms received pollen from a far greater number of sires than trees within remnant forest. The study shows that shade coffee habitats support specialized native pollinators that enhance the fecundity and genetic diversity of remnant native trees.

  20. 海南滨海木麻黄林下三种乡土树种的光合特性%Photosynthetic characteristics of three native tree species in coastal Casuarina equisetifolia plantation in Hainan

    Institute of Scientific and Technical Information of China (English)

    姚宝琪; 刘强; 蔡梓; 王孝杉

    2011-01-01

    The photosynthetic characteristics of three native tree species (T.lampas,C. Inophyllum and H. Sonora) in Hainan coastal Casuarina equisetifolia plantation were studied. The coastal sandy soil was treated by adding wood chips, bagasse and the control without adding anything in the plant pits. The net photosynthetic rate (Pn), stomatal conductance (Ccond), intercellular CO2 concentration (Ci) and transpiration rate (T,) were measured by using Li-6400 portable photosynthesis system. The results show that (1) Among the 3 tree species.the diurnal average maximum showed T. Lampas > H. Sonora > C. Inophyllum; (2) Among different soil treatments,the diurnal change of Pn, Ccorxl, C1and Tr of the three species showed the same variation. Only the Ccond and Tr of T.lampas and H. Sonora in the treatment by adding bagasse were absolutely higher than the treatment without adding anything in November, 2009, and the Ccond and T, of C. Inophyllum in the treatment by adding wood chips were higher than the treatment without adding anything in August, 2009; (3) Among the four measures in one year, the diurnal change of four photosynthesis parameters of T. Lampas and H. Sonora in three treatments of soil mainly showed a single peak. Except in February the diurnal change of P, and C, showed two peaks; the diurnal change of C. Inophyllum showed the same change except in May the diurnal change of/3,, T, and in February the diurnal change of C, showed two peaks; the Pn, Ccond, Tr of T.lampas reached the maximum in one year in August only the C, in May; and the Pn , Ccond,Ci, Tr of H. Sonora and C. Inophyllum reached the maximum in one year in August. (4)The three native species showed better net photosynthetic rateand water use efficiency, the Pn of T.lampas reached the maximum value (7.68 μmol·m-2s-1) in August in one year, the Pn of H, sonora and C. Inophyllum reached the maximum value(3.82 and 4.13 μmol· m-1s-1) in May; the Wwue. Of T.lampas, H. Sonora and C. Inophyllum reached the

  1. Tree nut allergens.

    Science.gov (United States)

    Roux, Kenneth H; Teuber, Suzanne S; Sathe, Shridhar K

    2003-08-01

    Allergic reactions to tree nuts can be serious and life threatening. Considerable research has been conducted in recent years in an attempt to characterize those allergens that are most responsible for allergy sensitization and triggering. Both native and recombinant nut allergens have been identified and characterized and, for some, the IgE-reactive epitopes described. Some allergens, such as lipid transfer proteins, profilins, and members of the Bet v 1-related family, represent minor constituents in tree nuts. These allergens are frequently cross-reactive with other food and pollen homologues, and are considered panallergens. Others, such as legumins, vicilins, and 2S albumins, represent major seed storage protein constituents of the nuts. The allergenic tree nuts discussed in this review include those most commonly responsible for allergic reactions such as hazelnut, walnut, cashew, and almond as well as those less frequently associated with allergies including pecan, chestnut, Brazil nut, pine nut, macadamia nut, pistachio, coconut, Nangai nut, and acorn.

  2. Multiple-purpose trees for pastoral farming in New Zealand: with emphasis on tree legumes. [Lucerne Tree: Medick Tree

    Energy Technology Data Exchange (ETDEWEB)

    Davies, D.J.G.; Macfarlane, R.P.

    1979-01-01

    The potential for soil conservation and agroforestry of several native and exotic legumes is discussed. Flowering period, chemical composition of leaves/pods, hardiness to frost and drought, timber value, forage potential for livestock and bees, ornamental value and other products are tabulated with information on up to 38 species. Two low-growing species that have proved useful for slope stabilization as well as forage are tree lucerne (Cytisus palmensis) and tree medick (Medicago arborea), the latter being shrubby and more suitable for cold districts. Gleditsia triacanthos is recommended as a shade and fodder tree for farm pasture.

  3. Combining QuickBird, LiDAR, and GIS topography indices to identify a single native tree species in a complex landscape using an object-based classification approach

    Science.gov (United States)

    Pham, Lien T. H.; Brabyn, Lars; Ashraf, Salman

    2016-08-01

    There are now a wide range of techniques that can be combined for image analysis. These include the use of object-based classifications rather than pixel-based classifiers, the use of LiDAR to determine vegetation height and vertical structure, as well terrain variables such as topographic wetness index and slope that can be calculated using GIS. This research investigates the benefits of combining these techniques to identify individual tree species. A QuickBird image and low point density LiDAR data for a coastal region in New Zealand was used to examine the possibility of mapping Pohutukawa trees which are regarded as an iconic tree in New Zealand. The study area included a mix of buildings and vegetation types. After image and LiDAR preparation, single tree objects were identified using a range of techniques including: a threshold of above ground height to eliminate ground based objects; Normalised Difference Vegetation Index and elevation difference between the first and last return of LiDAR data to distinguish vegetation from buildings; geometric information to separate clusters of trees from single trees, and treetop identification and region growing techniques to separate tree clusters into single tree crowns. Important feature variables were identified using Random Forest, and the Support Vector Machine provided the classification. The combined techniques using LiDAR and spectral data produced an overall accuracy of 85.4% (Kappa 80.6%). Classification using just the spectral data produced an overall accuracy of 75.8% (Kappa 67.8%). The research findings demonstrate how the combining of LiDAR and spectral data improves classification for Pohutukawa trees.

  4. Enumerating Trees

    CERN Document Server

    Kucharczyk, Robert A

    2012-01-01

    In this note we discuss trees similar to the Calkin-Wilf tree, a binary tree that enumerates all positive rational numbers in a simple way. The original construction of Calkin and Wilf is reformulated in a more algebraic language, and an elementary application of methods from analytic number theory gives restrictions on possible analogues.

  5. Native iron

    DEFF Research Database (Denmark)

    Brooks, Charles Kent

    2015-01-01

    , a situation unique in the Solar System. In such a world, iron metal is unstable and, as we all know, oxidizes to the ferric iron compounds we call 'rust'. If we require iron metal it must be produced at high temperatures by reacting iron ore, usually a mixture of ferrous (Fe2+) and ferric (Fe3+) oxides (Fe2O3......, hematite, or FeO.Fe2O3, magnetite), with carbon in the form of coke. This is carried out in a blast furnace. Although the Earth's core consists of metallic iron, which may also be present in parts of the mantle, this is inaccessible to us, so we must make our own. In West Greenland, however, some almost...... unique examples of iron metal, otherwise called 'native iron' or 'telluric iron', occur naturally....

  6. Tree compression with top trees

    DEFF Research Database (Denmark)

    Bille, Philip; Gørtz, Inge Li; Landau, Gad M.;

    2015-01-01

    We introduce a new compression scheme for labeled trees based on top trees. Our compression scheme is the first to simultaneously take advantage of internal repeats in the tree (as opposed to the classical DAG compression that only exploits rooted subtree repeats) while also supporting fast...

  7. Tree compression with top trees

    DEFF Research Database (Denmark)

    Bille, Philip; Gørtz, Inge Li; Landau, Gad M.

    2013-01-01

    We introduce a new compression scheme for labeled trees based on top trees [3]. Our compression scheme is the first to simultaneously take advantage of internal repeats in the tree (as opposed to the classical DAG compression that only exploits rooted subtree repeats) while also supporting fast...

  8. Tree compression with top trees

    DEFF Research Database (Denmark)

    Bille, Philip; Gørtz, Inge Li; Landau, Gad M.

    2015-01-01

    We introduce a new compression scheme for labeled trees based on top trees. Our compression scheme is the first to simultaneously take advantage of internal repeats in the tree (as opposed to the classical DAG compression that only exploits rooted subtree repeats) while also supporting fast...

  9. Native Americans with Diabetes

    Science.gov (United States)

    ... Read the MMWR Science Clips Native Americans with Diabetes Better diabetes care can decrease kidney failure Language: ... between 1996 and 2013. Problem Kidney failure from diabetes was highest among Native Americans. Native Americans are ...

  10. Context trees

    OpenAIRE

    Ganzinger, Harald; Nieuwenhuis, Robert; Nivela, Pilar

    2001-01-01

    Indexing data structures are well-known to be crucial for the efficiency of the current state-of-the-art theorem provers. Examples are \\emph{discrimination trees}, which are like tries where terms are seen as strings and common prefixes are shared, and \\emph{substitution trees}, where terms keep their tree structure and all common \\emph{contexts} can be shared. Here we describe a new indexing data structure, \\emph{context trees}, where, by means of a limited kind of conte...

  11. Two Trees

    OpenAIRE

    Cochrane, John. H.; Longstaff, Francis A.; Santa-Clara, Pedro

    2004-01-01

    We solve a model with two “Lucas trees.†Each tree has i.i.d. dividend growth. The investor has log utility and consumes the sum of the two trees’ dividends. This model produces interesting asset-pricing dynamics, despite its simple ingredients. Investors want to rebalance their portfolios after any change in value. Since the size of the trees is fixed, however, prices must adjust to offset this desire. As a result, expected returns, excess returns, and return volatility all vary throug...

  12. Análise da rentabilidade econômica dos reflorestamentos com essências nativas brasileiras: o caso do Estado de São Paulo Economic profitability analysis of reforestation with native trees: the state of São Paulo's case

    Directory of Open Access Journals (Sweden)

    José Arimatéia Rabelo Machado

    2002-01-01

    Full Text Available No presente trabalho, analisou-se a rentabilidade econômica dos reflorestamentos com essências nativas brasileiras destinados à produção de toras, considerando como caso em estudo o Estado de São Paulo. Na revisão de literatura, constatou-se que poucos são os trabalhos publicados a respeito do reflorestamento com essências nativas e com um longo período de observação. Dentre esses trabalhos, destacou-se um, no qual os autores recomendaram três espécies florestais como viáveis para reflorestamentos comerciais: Centrolobium tomentosum (araruva, Balfourodendron riedelianum (pau-marfim e Araucaria angustifolia (pinheiro-brasileiro. Após recuperar as informações técnicas dos experimentos com essas essências nativas, realizou-se a análise de rentabilidade econômica de possíveis projetos, em condições deterministas e de risco. Concluiu-se que, do ponto de vista privado, os projetos de reflorestamento com essas essências nativas são viáveis economicamente. Diante desse cenário, sugerem-se novas linhas de pesquisa técnica capazes de gerar resultados que assegurem maior confiabilidade e ampliação na rentabilidade dos projetos de reflorestamento com essências nativas brasileiras.This paper analyzes the economic profitability of native-tree reforestation for the production of sawlogs. The projects evaluated are experimental rather than commercial and are located in the Brazilian state of São Paulo. These experimental plots were reforested with the native tree species Centrolobium tomentosum ("araruva", Balforodendron riedelianum ("pau-marfim" and Araucaria angustifolia ("pinheiro-brasileiro", recommended for their economic value by a previous evaluation of long-term native-tree reforestation. Economic profitability analyses were made under both deterministic and risk conditions using data from the reforestation experiments. It was found that all the experiments would be profitable. This paper concludes with the suggestion

  13. Evaluation and Selection of Native Ornamental Tree Species Resources of Symplocaceae in Chongqing%重庆市山矾科乡土观赏树种资源评价与筛选

    Institute of Scientific and Technical Information of China (English)

    刘燕新; 方文; 马立辉; 陈丽花

    2012-01-01

    采用资料查阅、访问和实地调查相结合的方法,对重庆市山矾科树种资源进行调查.运用层次分析法建立了山矾科树种评价体系,确定了评价因子及其权重,对山矾科树种进行客观定量评价.结果表明,重庆市山矾科树种有15种,其中小乔木9种,乔木6种,主要分布于南川、奉节、主城区等区县,分别占重庆市山矾科树种总数的80%、46.7%和40.0%;四川山矾、棱角山矾和黄牛奶树适应性强、生态效益好、观赏价值高,在城市森林建设中应大力推广应用.%This paper studied on tree species resources of Symplocaceae in Chongqing through field survey methods combining with literature review and visit, and then established tree species resources of Symplocaceae evaluation system by using method of Analytical Hierarchy Process ( AHP) , confirmed e-valuation factors and their weights to evaluate tree species resources of Symplocaceae objectively and quantificationally. The results showed that there were 15 species of Symplocaceae in Chongqing, including 9 species of small trees and 6 species of trees, which mainly distributed in Nanchuan, Fengjie and urban district, accounted for 80% , 46. 7% and 40% of Symplocos tree species number in Chongqing respectively. S. setchuensis, S. tetragona, Chenet. Y. and S. laurina should be energetically applied in urban forest construction for they have strong adaptability, good ecological benefits and high ornamental value.

  14. Talking Trees

    Science.gov (United States)

    Tolman, Marvin

    2005-01-01

    Students love outdoor activities and will love them even more when they build confidence in their tree identification and measurement skills. Through these activities, students will learn to identify the major characteristics of trees and discover how the pace--a nonstandard measuring unit--can be used to estimate not only distances but also the…

  15. Flower and fruit production and insect pollination of the endangered Chilean tree, Gomortega keule in native forest, exotic pine plantation and agricultural environments Producción de flores y frutas y polinización por insectos de Gomortega keule en bosque nativo y en terrenos agrícolas, un árbol chileno en peligro de extinción

    Directory of Open Access Journals (Sweden)

    TONYA A LANDER

    2009-01-01

    Full Text Available This study was undertaken to discover whether patterns of flower and fruit production for Gomortega keule, an endangered Chilean tree, differ between exotic pine plantation, agricultural and native forest environments. A pilot study was also undertaken to identify the primary pollinators of G. keule. Although similar proportions of G. keule trees flowered in the agricultural and native forest áreas, more trees in the agricultural sites produced fruit compared to trees in the native forest sites. Flowering and fruiting of G. keule was extremely rare in the exotic pine plantations. Our data show that G. keule flowers are predominantly visited by syrphid flies in March-April, and that syrphids carry a greater proportion of G. keule pollen than the other insects collected. Native forest and low intensity agricultural systems appear to provide habitat in which syrphids forage and G. keule is able to produce fruit successfully, but exotic pine plantation does not; suggesting that a landscape made up of a mosaic of different landuse types is not necessarily inimical to the continued reproduction of G. keule, but that the combination and types of landuses and intensity of management must be carefully considered.El presente estudio fue realizado con el objetivo de establecer si los patrones de producción de flores y frutos de Gomortega keule (Gomortegaceae, un árbol chileno en peligro de extinción, son diferentes entre áreas de plantaciones de pinos exóticos, terrenos agrícolas y áreas de bosque nativo. También fue llevado a cabo un estudio piloto para identificar los principales polinizadores de G. keule. A pesar de que en tierras agrícolas y en áreas de bosque nativo floreció una proporción similar de árboles de G. keule, en zonas agrícolas fructificó una mayor proporción en comparación con los árboles de áreas de bosque nativo. La floración y fructificación de G. keule fue extremadamente rara en las áreas de plantaciones de

  16. The Growth and Influencing Factors of Three Native Tree Species in Coastal Casuarina equisetifolia Plantation%滨海木麻黄林下3种乡土树种苗木的生长及其影响因素

    Institute of Scientific and Technical Information of China (English)

    姚宝琪; 刘强; 蔡梓; 王孝杉

    2011-01-01

    [ Objective ] The aim was to study the growth and environment factors of three native tree species ( Thespesiat lampas, Calophyllum inophyllum and Hernandia sonora) in Hainan in coastal Casuarina equisetifolia plantation. [ Method ] The coastal sandy soil was treated by adding wood chips, bagasse and the control without adding anything in the plant pits. The growth of three native tree species planted for one year was analyzed. [ Result] ① One year later, the survival rate showed an order of T. lampas > H. sonora > C. inophyllum;the net increase of basal diameter showed an order of H. sonora > T. lampas > C. inophyllum; while the net increase of height showed an order of T. lampas >C. inophyllum > H. Sonora. The difference of survival rate between T. lampas and C. inophyllum was extremely significant, the difference of survival rate between H. sonora and C. inophyllum was significant, but the survival rate between T. lampas and H. Sonora showed no significant difference. ② Among different soil treatments ,the survival rate of three native tree species in the treatment by adding wood chips, bagasse were higher than the treatment without adding anything, and the difference of survival rate of T. lampas between the treatment by adding wood chips, bagasse and the treatment without adding anything was extremely significant, but the treatment by adding wood chips and bagasse had not significant difference. ③ The growth of three native tree species showed some correlation with environment factors ( | r | > 0.3 ). The survival rate of T. lampas showed higher correlation with soil pH value and soil moisture, and the basal diameter and height of T. lampas showed some correlation with soil pH value and soil temperature. The survival rate of C. inophyllum showed higher correlation with soil PH value, soil temperature and light intensity, while the basal diameter and height of C. inophyllum showed some correlation with soil temperature. The survival rate

  17. National Program of Inspection of Non-Federal Dams, Tennessee. Spring Lake Dam (Candlewood II) Old Hickory Dam (Candlewood III) (Inventory Numbers TN 06930 & TN 06926), Hatchie River Basin, near Saulsbury, Hardeman County, Tennessee. Phase I Investigation Report,

    Science.gov (United States)

    1981-09-01

    20314. 1.3 Past Inspections - Past inspections of Spring Lake and Old Hickory Lake Dams include cursory inspections by George Moore and Troy Wedekind of...aertificate Cursory Preliminary Site Review Damage Potential Category:One Two Three Undetermined Inspection by: George Moore and Troy Wedekind Inspection...Cursory Preliminary Site Review Damage Potential Category:One Two Three __ Undetermined Inspection by: George Moore and Troy Wedekind Inspection Results

  18. Phylogenetic trees

    OpenAIRE

    Baños, Hector; Bushek, Nathaniel; Davidson, Ruth; Gross, Elizabeth; Harris, Pamela E.; Krone, Robert; Long, Colby; Stewart, Allen; WALKER, Robert

    2016-01-01

    We introduce the package PhylogeneticTrees for Macaulay2 which allows users to compute phylogenetic invariants for group-based tree models. We provide some background information on phylogenetic algebraic geometry and show how the package PhylogeneticTrees can be used to calculate a generating set for a phylogenetic ideal as well as a lower bound for its dimension. Finally, we show how methods within the package can be used to compute a generating set for the join of any two ideals.

  19. Game tree algorithms and solution trees

    NARCIS (Netherlands)

    W.H.L.M. Pijls (Wim); A. de Bruin (Arie)

    1998-01-01

    textabstractIn this paper, a theory of game tree algorithms is presented, entirely based upon the concept of solution tree. Two types of solution trees are distinguished: max and min trees. Every game tree algorithm tries to prune nodes as many as possible from the game tree. A cut-off criterion in

  20. Electron Tree

    DEFF Research Database (Denmark)

    Appelt, Ane L; Rønde, Heidi S

    2013-01-01

    The photo shows a close-up of a Lichtenberg figure – popularly called an “electron tree” – produced in a cylinder of polymethyl methacrylate (PMMA). Electron trees are created by irradiating a suitable insulating material, in this case PMMA, with an intense high energy electron beam. Upon discharge......, during dielectric breakdown in the material, the electrons generate branching chains of fractures on leaving the PMMA, producing the tree pattern seen. To be able to create electron trees with a clinical linear accelerator, one needs to access the primary electron beam used for photon treatments. We...... appropriated a linac that was being decommissioned in our department and dismantled the head to circumvent the target and ion chambers. This is one of 24 electron trees produced before we had to stop the fun and allow the rest of the accelerator to be disassembled....

  1. Electron Tree

    DEFF Research Database (Denmark)

    Appelt, Ane L; Rønde, Heidi S

    2013-01-01

    The photo shows a close-up of a Lichtenberg figure – popularly called an “electron tree” – produced in a cylinder of polymethyl methacrylate (PMMA). Electron trees are created by irradiating a suitable insulating material, in this case PMMA, with an intense high energy electron beam. Upon discharge......, during dielectric breakdown in the material, the electrons generate branching chains of fractures on leaving the PMMA, producing the tree pattern seen. To be able to create electron trees with a clinical linear accelerator, one needs to access the primary electron beam used for photon treatments. We...... appropriated a linac that was being decommissioned in our department and dismantled the head to circumvent the target and ion chambers. This is one of 24 electron trees produced before we had to stop the fun and allow the rest of the accelerator to be disassembled....

  2. Litter Species Composition and Topographic Effects on Fuels and Modeled Fire Behavior in an Oak-Hickory Forest in the Eastern USA.

    Science.gov (United States)

    Dickinson, Matthew B; Hutchinson, Todd F; Dietenberger, Mark; Matt, Frederick; Peters, Matthew P

    2016-01-01

    Mesophytic species (esp. Acer rubrum) are increasingly replacing oaks (Quercus spp.) in fire-suppressed, deciduous oak-hickory forests of the eastern US. A pivotal hypothesis is that fuel beds derived from mesophytic litter are less likely than beds derived from oak litter to carry a fire and, if they do, are more likely to burn at lower intensities. Species effects, however, are confounded by topographic gradients that affect overstory composition and fuel bed decomposition. To examine the separate and combined effects of litter species composition and topography on surface fuel beds, we conducted a common garden experiment in oak-hickory forests of the Ohio Hills. Each common garden included beds composed of mostly oak and mostly maple litter, representative of oak- and maple-dominated stands, respectively, and a mixture of the two. Beds were replenished each fall for four years. Common gardens (N = 16) were established at four topographic positions (ridges, benches on south- and northeast-facing slopes, and stream terraces) at each of four sites. Litter source and topographic position had largely independent effects on fuel beds and modeled fire dynamics after four years of development. Loading (kg m-2) of the upper litter layer (L), the layer that primarily supports flaming spread, was least in more mesic landscape positions and for maple beds, implying greater decomposition rates for those situations. Bulk density in the L layer (kg m-3) was least for oak beds which, along with higher loading, would promote fire spread and fireline intensity. Loading and bulk density of the combined fermentation and humic (FH) layers were least on stream terrace positions but were not related to species. Litter- and FH-layer moistures during a 5-day dry-down period after a rain event were affected by time and topographic effects while litter source effects were not evident. Characteristics of flaming combustion determined with a cone calorimeter pointed to greater fireline

  3. Interpreting Tree Ensembles with inTrees

    OpenAIRE

    Deng, Houtao

    2014-01-01

    Tree ensembles such as random forests and boosted trees are accurate but difficult to understand, debug and deploy. In this work, we provide the inTrees (interpretable trees) framework that extracts, measures, prunes and selects rules from a tree ensemble, and calculates frequent variable interactions. An rule-based learner, referred to as the simplified tree ensemble learner (STEL), can also be formed and used for future prediction. The inTrees framework can applied to both classification an...

  4. Native Health Research Database

    Science.gov (United States)

    ... APP WITH JAVASCRIPT TURNED OFF. THE NATIVE HEALTH DATABASE REQUIRES JAVASCRIPT IN ORDER TO FUNCTION. PLEASE ENTER ... To learn more about searching the Native Health Database, click here. Keywords Title Author Source of Publication ...

  5. Effects of exotic invasive trees on nitrogen cycling: a case study in Central Spain

    NARCIS (Netherlands)

    Castro-Diez, P.; González-Muñoz, N.; Alonso, A.; Gallardo, A.; Poorter, L.

    2009-01-01

    We assess the hypothesis that rates of nitrogen transformations in the soil are altered upon replacement of native by exotic trees, differing in litter properties. Ailanthus altissima and Robinia pseudoacacia, two common exotic trees naturalized in the Iberian Peninsula, were compared with the nativ

  6. Assisted migration: What it means to nursery managers and tree planters

    Science.gov (United States)

    Mary I. Williams; R. Kasten Dumroese

    2014-01-01

    Projections indicate that natural plant adaptation and migration may not keep pace with climate changes. This mismatch in rates will pose significant challenges for practitioners that select, grow, and outplant native tree species. Populations of native tree species planted today must be able to meet the climatic challenges they will face during this century. One...

  7. Planting and care of fine hardwood seedlings: diseases in hardwood tree plantings

    Science.gov (United States)

    Paula M. Pijut

    2006-01-01

    Hardwood trees planted for timber production, wildlife habitat, riparian buffers, native woodland restoration, windbreaks, watershed protection, erosion control, and conservation are susceptible to damage or even death by various native and exotic fungal or bacterial diseases. Establishment, growth, and the quality of the trees produced can be affected by these disease...

  8. Audubon Tree Study Program.

    Science.gov (United States)

    National Audubon Society, New York, NY.

    Included are an illustrated student reader, "The Story of Trees," a leaders' guide, and a large tree chart with 37 colored pictures. The student reader reviews several aspects of trees: a definition of a tree; where and how trees grow; flowers, pollination and seed production; how trees make their food; how to recognize trees; seasonal changes;…

  9. Removal of Pb(II), Cu(II), and Cd(II) from aqueous solutions by biochar derived from KMnO4 treated hickory wood.

    Science.gov (United States)

    Wang, Hongyu; Gao, Bin; Wang, Shenseng; Fang, June; Xue, Yingwen; Yang, Kai

    2015-12-01

    In this work, a novel approach was developed to prepare an engineered biochar from KMnO4 treated hickory wood through slow pyrolysis (600°C). Characterization experiments with various tools showed that the engineered biochar surface was covered with MnOx ultrafine particles. In comparison to the pristine biochar, the engineered biochar also had more surface oxygen-containing functional groups and much larger surface area. Batch sorption experiments showed that the engineered biochar had strong sorption ability to Pb(II), Cu(II), and Cd(II) with maximum sorption capacities of 153.1, 34.2, and 28.1mg/g, respectively, which were significantly higher than that of the pristine biochar. Batch sorption experiments also showed that the dosage, initial solution pH, and ionic strength affected the removal of the heavy metals by the biochars. The removal of the metals by the engineered biochar was mainly through surface adsorption mechanisms involving both the surface MnOx particles and oxygen-containing groups.

  10. Mycorrhizal detection of native and non-native truffles in a historic arboretum and the discovery of a new North American species, Tuber arnoldianum sp. nov.

    Science.gov (United States)

    Healy, Rosanne A; Zurier, Hannah; Bonito, Gregory; Smith, Matthew E; Pfister, Donald H

    2016-10-01

    During a study comparing the ectomycorrhizal root communities in a native forest with those at the Arnold Arboretum in Massachusetts (USA), the European species Tuber borchii was detected on the roots of a native red oak in the arboretum over two successive years. Since T. borchii is an economically important edible truffle native to Europe, we conducted a search of other roots in the arboretum to determine the extent of colonization. We also wanted to determine whether other non-native Tuber species had been inadvertently introduced into this 140-year-old Arboretum because many trees were imported into the site with intact soil and roots prior to the 1921 USDA ban on these horticultural practices in the USA. While T. borchii was not found on other trees, seven other native and exotic Tuber species were detected. Among the North American Tuber species detected from ectomycorrhizae, we also collected ascomata of a previously unknown species described here as Tuber arnoldianum. This new species was found colonizing both native and non-native tree roots. Other ectomycorrhizal taxa that were detected included basidiomycetes in the genera Amanita, Russula, Tomentella, and ascomycetes belonging to Pachyphlodes, Helvella, Genea, and Trichophaea. We clarify the phylogenetic relationships of each of the Tuber species detected in this study, and we discuss their distribution on both native and non-native host trees.

  11. Review of Invasive Riparian Trees that Impact USACE Ecosystem Restoration Projects

    Science.gov (United States)

    2016-08-01

    part of the woody structure in southwest riparian habitats (Stromberg et al. 2009). Tree-of-Heaven ( Ailanthus altissima). Figure 3. Tree-of...Heaven ( Ailanthus altissima) (Photo credit: Chuck Bargeron, University of Georgia). The Tree-of-Heaven ( Ailanthus altissima) is a tree native to...and forest fauna in Eastern North America. Forests 3:840-852. Hoshovsky, M. C. 1986. Element Stewardship Abstract for Ailanthus altissima, Tree-of

  12. Aspen Trees.

    Science.gov (United States)

    Canfield, Elaine

    2002-01-01

    Describes a fifth-grade art activity that offers a new approach to creating pictures of Aspen trees. Explains that the students learned about art concepts, such as line and balance, in this lesson. Discusses the process in detail for creating the pictures. (CMK)

  13. NATIVE VS NON-NATIVE ENGLISH TEACHERS

    Directory of Open Access Journals (Sweden)

    Masrizal Masrizal

    2013-02-01

    Full Text Available Although the majority of English language teachers worldwide are non-native English speakers (NNS, no research was conducted on these teachers until recently. A pioneer research by Peter Medgyes in 1994 took quite a long time until the other researchers found their interests in this issue. There is a widespread stereotype that a native speaker (NS is by nature the best person to teach his/her foreign language. In regard to this assumption, we then see a very limited room and opportunities for a non native teacher to teach language that is not his/hers. The aim of this article is to analyze the differences among these teachers in order to prove that non-native teachers have equal advantages that should be taken into account. The writer expects that the result of this short article could be a valuable input to the area of teaching English as a foreign language in Indonesia.

  14. LocTree3 prediction of localization

    DEFF Research Database (Denmark)

    Goldberg, T.; Hecht, M.; Hamp, T.

    2014-01-01

    The prediction of protein sub-cellular localization is an important step toward elucidating protein function. For each query protein sequence, LocTree2 applies machine learning (profile kernel SVM) to predict the native sub-cellular localization in 18 classes for eukaryotes, in six for bacteria...

  15. Field guide to trees of Southern Africa

    Directory of Open Access Journals (Sweden)

    Rishan Singh

    2012-09-01

    Full Text Available The mainland region of Africa is Southern Africa because it is considered to be robust with an estimate of around 1700 tree species that are native and a couple 100 more that are alien, but have become accustomed to the natural environment; invading, penetrating and replacing vegetation.

  16. Leaf traits and gas exchange in saplings of native tree species in the Central Amazon Características foliares e trocas gasosas em arvoretas de espécies nativas da Amazônia Central

    Directory of Open Access Journals (Sweden)

    Keila Rego Mendes

    2010-12-01

    Full Text Available Global climate models predict changes on the length of the dry season in the Amazon which may affect tree physiology. The aims of this work were to determine the effect of the rainfall regime and fraction of sky visible (FSV at the forest understory on leaf traits and gas exchange of ten rainforest tree species in the Central Amazon, Brazil. We also examined the relationship between specific leaf area (SLA, leaf thickness (LT, and leaf nitrogen content on photosynthetic parameters. Data were collected in January (rainy season and August (dry season of 2008. A diurnal pattern was observed for light saturated photosynthesis (Amax and stomatal conductance (g s, and irrespective of species, Amax was lower in the dry season. However, no effect of the rainfall regime was observed on g s nor on the photosynthetic capacity (Apot, measured at saturating [CO2]. Apot and leaf thickness increased with FSV, the converse was true for the FSV-SLA relationship. Also, a positive relationship was observed between Apot per unit leaf area and leaf nitrogen content, and between Apot per unit mass and SLA. Although the rainfall regime only slightly affects soil moisture, photosynthetic traits seem to be responsive to rainfall-related environmental factors, which eventually lead to an effect on Amax. Finally, we report that little variation in FSV seems to affect leaf physiology (Apot and leaf anatomy (leaf thickness.Os modelos climáticos globais prevêem mudanças na extensão da época seca na Amazônia, o que pode afetar a fisiologia das árvores. Os objetivos deste trabalho foram determinar o efeito da sazonalidade da precipitação e fração de céu visível (FSV no sub-bosque da floresta nas características foliares e trocas gasosas de 10 espécies florestais da Amazônia Central. Também examinou-se a relação entre área foliar específica (SLA, espessura da folha (LT e nitrogênio foliar em parâmetros fotossintéticos. Os resultados foram coletados nos

  17. Unimodular trees versus Einstein trees

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, Enrique; Gonzalez-Martin, Sergio [Universidad Autonoma, Instituto de Fisica Teorica, IFT-UAM/CSIC, Madrid (Spain); Universidad Autonoma de Madrid, Departamento de Fisica Teorica, Madrid (Spain); Martin, Carmelo P. [Universidad Complutense de Madrid (UCM), Departamento de Fisica Teorica I Facultad de Ciencias Fisicas, Madrid (Spain)

    2016-10-15

    The maximally helicity violating tree-level scattering amplitudes involving three, four or five gravitons are worked out in Unimodular Gravity. They are found to coincide with the corresponding amplitudes in General Relativity. This a remarkable result, insofar as both the propagators and the vertices are quite different in the two theories. (orig.)

  18. Unimodular Trees versus Einstein Trees

    CERN Document Server

    Alvarez, Enrique; Martin, Carmelo P

    2016-01-01

    The maximally helicity violating (MHV) tree level scattering amplitudes involving three, four or five gravitons are worked out in Unimodular Gravity. They are found to coincide with the corresponding amplitudes in General Relativity. This a remarkable result, insofar as both the propagators and the vertices are quite different in both theories.

  19. Unimodular trees versus Einstein trees

    Science.gov (United States)

    Álvarez, Enrique; González-Martín, Sergio; Martín, Carmelo P.

    2016-10-01

    The maximally helicity violating tree-level scattering amplitudes involving three, four or five gravitons are worked out in Unimodular Gravity. They are found to coincide with the corresponding amplitudes in General Relativity. This a remarkable result, insofar as both the propagators and the vertices are quite different in the two theories.

  20. Determinación de Factores de Emisión de Compuestos Orgánicos Volátiles de Dos Especies Arbóreas Nativas de La Región Metropolitana, Chile Determination of Emission Factors of Volatile Organic Compounds of Two Native Tree Species in Chile's Metropolitan Region

    Directory of Open Access Journals (Sweden)

    M. Préndez

    2005-01-01

    Full Text Available En este trabajo se informa sobre algunos factores de emisión para seis monoterpenos emitidos por Cryptocarya alba (peumo y Schinus molle (pimiento, especies que corresponden al 2,5% de las especies arbóreas de la Región Metropolitana de Chile. Los compuestos orgánicos volátiles biogénicos (COVsB participan en la formación de ozono troposférico y los modelos para elaborar estrategias de control y disminución de las concentraciones de ozono requieren de los factores de emisión. En este sentido, existe poca información para las especies arbóreas nativas chilenas, como las consideradas en este estudio. Se usó el encierro estático y la adsorción en Tenax para el muestreo y GC-FID para la cuantificación de COVsB. Los mayores factores de emisión en peumo fueron: 0.0049 a 0.0165 µgg-1hsh-1 para cineol y 0.0030 a 0.0117 µgg-1hsh-1 para limoneno. En pimiento los valores extremos fueron: 0.0097-0.128 µgg-1hsh-1 para a-pineno y 0.0029 a 0.108 µgg-1hsh-1 para 3-careno. Los resultados muestran que los factores de emisión son muy dependientes de las condiciones ambientales y de la especie arbórea.The present study reports on some emission factors for six monoterpenes released by Cryptocarya alba (peumo and Schinus molle (pimiento which represent 2.5 % of the tree species occurring in Chile's Metropolitan Region. Biogenic volatile organic compounds (BVOCs participate in tropospheric ozone formation, and models used to design strategies to control and/or lower ozone concentrations require knowing the emission factors of these BVOCs. In this context, there is very little information about Chilean native tree species as those considered in this study. The static enclosure method and Tenax adsorption were used for sampling and GC-FID was used for quantification of BVOCs. The highest emission factors for peumo were 0.0049 to 0.0165 gg-1dwh-1 for cineole and 0.0030 to 0.0117 gg-1dwh-1 for limonene; for pimiento, the highest values were 0

  1. The combined effects of remnant vegetation and tree planting on farmland birds.

    Science.gov (United States)

    Cunningham, Ross B; Lindenmayer, David B; Crane, Mason; Michael, Damian; MacGregor, Christopher; Montague-Drake, Rebecca; Fischer, Joern

    2008-06-01

    Biodiversity conservation on agricultural land is a major issue worldwide. We estimated separate and joint effects of remnant native woodland vegetation and recent tree plantings on birds on farms (approximately 500-1000 ha) in the heavily cleared wheat and sheep belt of southern Australia. Much of the variation (>70%) in bird responses was explained by 3 factors: remnant native-vegetation attributes (native grassland, scattered paddock trees, patches of remnant native woodland); presence or absence of planted native trees; and the size and shape of tree plantings. In terms of the number of species, remnant native vegetation was more important than tree planting, in a 3:1 ratio, approximately. Farms with high values for remnant native vegetation were those most likely to support declining or vulnerable species, although some individual species of conservation concern occurred on farms with large plantings. Farm management for improved bird conservation should account for the cumulative and complementary contributions of many components of remnant native-vegetation cover (e.g., scattered paddock trees and fallen timber) as well as areas of restored native vegetation.

  2. Mycorrhizal inoculation of pecan seedlings with some marketable truffles

    Directory of Open Access Journals (Sweden)

    Gian M. Benucci

    2013-12-01

    Full Text Available Pecan is the common name of Carya illinoinensis (Wangenh. K. Koch, an ectomycorrhizal tree native to North America, also frequently known as hickory. Mycorrhizal inoculations of pecan seedlings with: Tuber aestivum Vittad., T. borchii Vittad., T. indicum Cooke & Massee, and T. lyonii Butters are described and discussed.

  3. Allometry, biomass, and chemical content of novel African Tulip Tree (Spathodea campanulata) forests in Puerto Rico

    Science.gov (United States)

    Ariel E. Lugo; Oscar J. Abelleira; Alexander Collado; Christian A. Viera; Cynthia Santiago; Diego O. Velez; Emilio Soto; Giovanni Amaro; Graciela Charon; Jr. Colon; Jennifer Santana; Jose L. Morales; Katherine Rivera; Luis Ortiz; Luis Rivera; Mianel Maldonado; Natalia Rivera; Norelis J. Vazquez

    2011-01-01

    The African tulip tree, Spathodea campanulata, the most common tree in Puerto Rico, forms novel forest types with mixtures of native and other introduced tree species. Novel forests increase in area in response to human activity and there is no information about their biomass accumulation and nutrient cycling. We established allometric relationships and chemically...

  4. Fertilização de mudas de espécies arbóreas nativas e exóticas Fertilization of native and exotic tree seedlings

    Directory of Open Access Journals (Sweden)

    Sebastião Pires de Moraes Neto

    2003-04-01

    Full Text Available Doses crescentes de fertilizante de liberação controlada (FLC foram comparadas com fertilização convencional e tratamento sem fertilização. Estes tratamentos foram testados em mudas das pioneiras Guazuma ulmifolia (mutambo, Eucalyptus grandis e Pinus caribaea var. caribaea, da secundária inicial Peltophorum dubium (canafístula e da clímax Calycophyllum spruceanum (mulateiro, as quais cresceram em casa de vegetação. As mudas foram cultivadas em tubetes de 50 cm³ de capacidade, tendo como substrato uma mistura contendo 50% de húmus de minhoca, 30% de casca de eucalipto decomposta e 20% de casca de arroz carbonizada, em base volumétrica. Aos 125 dias após a semeadura, as mudas de G. ulmifolia, E. grandis e P. dubium submetidas à fertilização convencional apresentaram maior crescimento em altura e biomassa seca da parte aérea comparados aos dos tratamentos que receberam FLC. Contudo, para estas espécies, a biomassa seca da raiz das mudas submetidas ao tratamento convencional foram semelhantes à das mudas produzidas com as duas maiores doses de FLC (4,28 e 6, 42 kg/m³ de substrato, e a razão entre raiz e parte aérea foi maior para a dose de 6,42 kg/m³ (FLC, comparada à do tratamento convencional para as duas primeiras espécies. O Calycophyllum spruceanum e o Pinus caribaea var. caribaea tiveram pequeno desenvolvimento em todos os tratamentos, aos 125 dias.Increasing doses of resin-coated controlled release fertilizers (CRF were compared with conventional fertilization and treatment without fertilizer. Five species of tree seedlings were used: the pioneers Guazuma ulmifolia (mutambo, Eucalyptus grandis and Pinus caribaea var. caribaea, the early secondary Peltophorum dubium ("canafístula" and the climax Calycophyllum spruceanum ("mulateiro", grown in greenhouse. The seedlings were tilled in plastic tubes of 50 cm³ capacity, receiving as substrate a mixture of 50% earthworm humus, 30% decomposed eucalypt bark, and 20

  5. Sistema de blocos prensados para produção de mudas de três espécies arbéreas nativas Pressed block system for seedling production of three native forest tree species

    Directory of Open Access Journals (Sweden)

    Luciano Keller

    2009-04-01

    to 150 days after transplantation. The next step was to determine the dry matter weight of the aerial part and root system. To evaluate the behavior of the seedlings produced in the various treatments under field conditions, the survival rate at two months from planting was measured. The seedlings produced by the pressed block system showed a growth higher than or similar to those produced in plastic bags or tubes. Under field conditions, no statistical differences were observed for survival rate and growth of the seedlings from the pressed blocks, plastic bags and tubes. The pressed block system was found to be technically feasible for the production of seedlings of the forest trees species studied.

  6. MBS Native Plant Communities

    Data.gov (United States)

    Minnesota Department of Natural Resources — This data layer contains results of the Minnesota County Biological Survey (MCBS). It includes polygons representing the highest quality native plant communities...

  7. Finite Sholander Trees, Trees, and their Betweenness

    CERN Document Server

    Chvátal, Vašek; Schäfer, Philipp Matthias

    2011-01-01

    We provide a proof of Sholander's claim (Trees, lattices, order, and betweenness, Proc. Amer. Math. Soc. 3, 369-381 (1952)) concerning the representability of collections of so-called segments by trees, which yields a characterization of the interval function of a tree. Furthermore, we streamline Burigana's characterization (Tree representations of betweenness relations defined by intersection and inclusion, Mathematics and Social Sciences 185, 5-36 (2009)) of tree betweenness and provide a relatively short proof.

  8. Listen to the Natives

    Science.gov (United States)

    Prensky, Marc

    2006-01-01

    "Digital natives" refer to today's students because they are native speakers of technology, fluent in the digital language of computers, video games, and the Internet. Those who were not born into the digital world are referred to as digital immigrants. Educators, considered digital immigrants, have slid into the 21st century--and into the digital…

  9. Phytophagous insects on native and non-native host plants: combining the community approach and the biogeographical approach.

    Directory of Open Access Journals (Sweden)

    Kim Meijer

    Full Text Available During the past centuries, humans have introduced many plant species in areas where they do not naturally occur. Some of these species establish populations and in some cases become invasive, causing economic and ecological damage. Which factors determine the success of non-native plants is still incompletely understood, but the absence of natural enemies in the invaded area (Enemy Release Hypothesis; ERH is one of the most popular explanations. One of the predictions of the ERH, a reduced herbivore load on non-native plants compared with native ones, has been repeatedly tested. However, many studies have either used a community approach (sampling from native and non-native species in the same community or a biogeographical approach (sampling from the same plant species in areas where it is native and where it is non-native. Either method can sometimes lead to inconclusive results. To resolve this, we here add to the small number of studies that combine both approaches. We do so in a single study of insect herbivory on 47 woody plant species (trees, shrubs, and vines in the Netherlands and Japan. We find higher herbivore diversity, higher herbivore load and more herbivory on native plants than on non-native plants, generating support for the enemy release hypothesis.

  10. Cultural Resources of the Ohio River Floodplain in Illinois,

    Science.gov (United States)

    1977-10-15

    americana), hickories, .nd sweet gum, with occasional black walnut (Juailapns _igrij), butternut (Iluglans cinerea), and pecan ( Carya illinoensis ) on better...Quercius velutina), shingle oak (Quercus imbricaria), and various hickories, particularly the more xeric species such as black hickory ( Carya texana...where soil is thin or exposure hazardous. Stands of various hickories ( Carya ) are interspersed. Smaller trees might include dogwood (Cornus spp.) and

  11. Modular Tree Automata

    DEFF Research Database (Denmark)

    Bahr, Patrick

    2012-01-01

    Tree automata are traditionally used to study properties of tree languages and tree transformations. In this paper, we consider tree automata as the basis for modular and extensible recursion schemes. We show, using well-known techniques, how to derive from standard tree automata highly modular r...

  12. Simple street tree sampling

    Science.gov (United States)

    David J. Nowak; Jeffrey T. Walton; James Baldwin; Jerry. Bond

    2015-01-01

    Information on street trees is critical for management of this important resource. Sampling of street tree populations provides an efficient means to obtain street tree population information. Long-term repeat measures of street tree samples supply additional information on street tree changes and can be used to report damages from catastrophic events. Analyses of...

  13. Modular tree automata

    DEFF Research Database (Denmark)

    Bahr, Patrick

    2012-01-01

    Tree automata are traditionally used to study properties of tree languages and tree transformations. In this paper, we consider tree automata as the basis for modular and extensible recursion schemes. We show, using well-known techniques, how to derive from standard tree automata highly modular...

  14. Establishment and growth of native hardwood and conifer seedlings underplanted in thinned Douglas-fir stands.

    Science.gov (United States)

    Kathleen G. Maas-Hebner; William H. Emmingham; David L. Larson; Samuel S. Chan

    2005-01-01

    Five conifers and two hardwoods native to the Pacific Northwest were planted under four overstory densities of 30-year-old plantations of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) in the Oregon Coast Range, USA. Stand treatments were unthinned (547 trees ha-1), narrow thin (252 trees ha-1),...

  15. Native grasslands fertilize themselves

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — News article about Lostwood National Wildlife Refuge and how the native soils and plants function to stimulate the system, creating a more productive grassland.

  16. Chapter 10: Establishing native trees on legacy surface mines

    Science.gov (United States)

    J.A. Burger; C.E. Zipper; P.N. Angel; N. Hall; J.G. Skousen; C.D. Barton; S. Eggerud

    2017-01-01

    More than 1 million acres have been surface mined for coal in the Appalachian region. Today, much of this land is unmanaged, unproductive, and covered with nonnative plants. Establishing productive forests on such lands will aid restoration of ecosystem services provided by forests—services such as watershed protection, water quality enhancement, carbon storage, and...

  17. Reforesting unused surface mined lands by replanting with native trees

    Science.gov (United States)

    Patrick N. Angel; James A. Burger; Carl E. Zipper; Scott Eggerud

    2012-01-01

    More than 600,000 ha (1.5 million ac) of mostly forested land in the Appalachian region were surface mined for coal under the Surface Mining Control and Reclamation Act. Today, these lands are largely unmanaged and covered with persistent herbaceous species, such as fescue (Festuca spp.) and sericea lespedeza (Lespedeza cuneata [Dum. Cours.] G. Don,) and a mix of...

  18. Leucaena leucocephala and adjacent native limestone forest habitats contrast in soil properties on Tinian Island.

    Science.gov (United States)

    Marler, Thomas E; Dongol, Nirmala; Cruz, Gil N

    2016-01-01

    An ex situ germplasm collection of the endangered Cycas micronesica was established in a transition zone between biodiverse native forest and mature stands of the invasive species Leucaena leucocephala. Soil chemical properties were determined for the 2 tree cover types to inform management decisions. Total carbon, total nitrogen, calcium, and net ammonification were greater in native forest cover than in L. leucocephala patches. Net nitrification and net mineralization were greater under L. leucocephala cover. Trace metals also differed between the 2 forest cover types, with chromium, cobalt, and nickel accumulating to greater concentration under L. leucocephala cover and zinc accumulating to greater concentration under native forest cover. The results indicated that L. leucocephala cover generated substantial changes in soil chemical properties when compared with native forest tree cover, illuminating one means by which understory vegetation may be affected by changes in invasive tree cover.

  19. Records of unsuccessful attack by Anoplophora glabripennis (Coleoptera: Cerambycidae) on broadleaf trees of questionable suitability in Ontario

    Science.gov (United States)

    Discovery of the non-native Anoplophora glabripennis Motschulsky (Coleoptera: Cerambycidae) in Ontario, Canada, in 2003 led to the implementation of an eradication program. The plan consisted of removing all infested trees and all trees within 400 m of an infested tree belonging to a genus consider...

  20. Trees and the City: Diversity and Composition along a Neotropical Gradient of Urbanization

    Directory of Open Access Journals (Sweden)

    Rubén Ortega-Álvarez

    2011-01-01

    Full Text Available In this study we assessed tree species richness, density, and composition patterns along a gradient of urbanization of a megacity. Our results show that total, native, and exotic tree densities were highest in green areas where larger spaces are considered for greening purposes. Conversely, total, native, and exotic tree species richness were highest in land uses with intermediate levels of urban development (residential, residential-commercial areas. Not finding highest tree species richness in less developed urban areas suggests that cultural factors may shape the array of species that are planted within cities. Supporting this, tree composition analyses showed that green areas are comprised of different tree species when compared to the rest of the studied urban land uses. Thus, our results suggest that, to increase the ecological quality of cities, residents and managers should be encouraged to select a greater variety of trees to promote heterogeneous green areas.

  1. Native listening: The flexibility dimension

    NARCIS (Netherlands)

    Cutler, A.

    2012-01-01

    The way we listen to spoken language is tailored to the specific benefit of native-language speech input. Listening to speech in non-native languages can be significantly hindered by this native bias. Is it possible to determine the degree to which a listener is listening in a native-like manner? Pr

  2. Healthy,Happy trees

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Healthy trees are important to us all. Trees provide shade, beauty, and homes for wildlife. Trees give us products like paper and wood. Trees can give us all this only if they are healthy.They must be well cared for to remain healthy.

  3. Modelling the long term effects of an introduced herbivore on spread of an invasive tree

    Science.gov (United States)

    Melaleuca quinquenervia (Cav.) Blake (hereafter melaleuca) is an invasive tree from Australia that has spread over the freshwater ecosystems of southern Florida, displacing native vegetation such as slash pine (Pinus elliottii), pond cypress (Taxodium ascendens), and loblolly bay (Gordonia lasianthu...

  4. Trees and shrubs of the Bartlett Experimental Forest, Carroll County, New Hampshire

    Science.gov (United States)

    Stanley M. Filip; Elbert L., Jr. Little; Elbert L. Little

    1971-01-01

    Sixty-five species of trees and shrubs have been identified as native on the Bartlett Experimental Forest. These species are listed in this paper to provide a record of the woody vegetation of the area.

  5. Classification and regression trees

    CERN Document Server

    Breiman, Leo; Olshen, Richard A; Stone, Charles J

    1984-01-01

    The methodology used to construct tree structured rules is the focus of this monograph. Unlike many other statistical procedures, which moved from pencil and paper to calculators, this text's use of trees was unthinkable before computers. Both the practical and theoretical sides have been developed in the authors' study of tree methods. Classification and Regression Trees reflects these two sides, covering the use of trees as a data analysis method, and in a more mathematical framework, proving some of their fundamental properties.

  6. The Buffalo Creek Archaeological Project. Volume 1: Background and Testing at 3MS346 and 3CG847 Mississippi and Craighead Counties, Arkansas

    Science.gov (United States)

    1992-01-01

    shagbark hickory ( Carya ovata), and pecan ( Carya illinoensis ). These trees dominate the vegetation on well-drained elevated land such as tho-se areas...strongly acidic soil (Steyermark 1959:95, 120). Chinquapin (Castanea ozarkensis), black or sourgum (Nyssa sylvatica), black hickory ( Carya texana...white oak, mockernut hickory ( Carya tomentosa), black hickory, white hickory ( Carya alba), flowering dogwoo-T-,whiT𔃻eFash(Fraxinus americana

  7. Immigrants and Native Workers

    DEFF Research Database (Denmark)

    Foged, Mette; Peri, Giovanni

    Using a database that includes the universe of individuals and establishments in Denmark over the period 1991-2008 we analyze the effect of a large inflow of non-European (EU) immigrants on Danish workers. We first identify a sharp and sustained supply-driven increase in the inflow of non......-EU immigrants in Denmark, beginning in 1995 and driven by a sequence of international events such as the Bosnian, Somalian and Iraqi crises. We then look at the response of occupational complexity, job upgrading and downgrading, wage and employment of natives in the short and long run. We find...... that the increased supply of non-EU low skilled immigrants pushed native workers to pursue more complex occupations. This reallocation happened mainly through movement across firms. Immigration increased mobility of natives across firms and across municipalities but it did not increase their probability...

  8. Is Nativism Sufficient?

    Science.gov (United States)

    Braine, Martin D. S.

    1994-01-01

    Provides a brief history of the empiricism-nativism issue, considering present-day intellectual roots of nativist and empiricist inclinations. A schema is proposed for explaining the ontogenetic origin of an innate attribute or principle relevant to language. An attempt is made to explain the origin of primitives as derived by learning. (Contains…

  9. Non-native seagrass

    NARCIS (Netherlands)

    van Tussenbroek, B.I.; van Katwijk, M.M.; Bouma, T.J.; van der Heide, T.; Govers, L.L.; Leuven, R.S.E.W.

    2016-01-01

    Seagrasses comprise 78 species and are rarely invasive. But the seagrass Halophila stipulacea, firstly recorded in the Caribbean in the year 2002, has spread quickly throughout the region. Previous works have described this species as invasive in the Caribbean, forming dense mats that exclude native

  10. Fault-Tree Compiler

    Science.gov (United States)

    Butler, Ricky W.; Boerschlein, David P.

    1993-01-01

    Fault-Tree Compiler (FTC) program, is software tool used to calculate probability of top event in fault tree. Gates of five different types allowed in fault tree: AND, OR, EXCLUSIVE OR, INVERT, and M OF N. High-level input language easy to understand and use. In addition, program supports hierarchical fault-tree definition feature, which simplifies tree-description process and reduces execution time. Set of programs created forming basis for reliability-analysis workstation: SURE, ASSIST, PAWS/STEM, and FTC fault-tree tool (LAR-14586). Written in PASCAL, ANSI-compliant C language, and FORTRAN 77. Other versions available upon request.

  11. Categorizing Ideas about Trees: A Tree of Trees

    Science.gov (United States)

    Fisler, Marie; Lecointre, Guillaume

    2013-01-01

    The aim of this study is to explore whether matrices and MP trees used to produce systematic categories of organisms could be useful to produce categories of ideas in history of science. We study the history of the use of trees in systematics to represent the diversity of life from 1766 to 1991. We apply to those ideas a method inspired from coding homologous parts of organisms. We discretize conceptual parts of ideas, writings and drawings about trees contained in 41 main writings; we detect shared parts among authors and code them into a 91-characters matrix and use a tree representation to show who shares what with whom. In other words, we propose a hierarchical representation of the shared ideas about trees among authors: this produces a “tree of trees.” Then, we categorize schools of tree-representations. Classical schools like “cladists” and “pheneticists” are recovered but others are not: “gradists” are separated into two blocks, one of them being called here “grade theoreticians.” We propose new interesting categories like the “buffonian school,” the “metaphoricians,” and those using “strictly genealogical classifications.” We consider that networks are not useful to represent shared ideas at the present step of the study. A cladogram is made for showing who is sharing what with whom, but also heterobathmy and homoplasy of characters. The present cladogram is not modelling processes of transmission of ideas about trees, and here it is mostly used to test for proximity of ideas of the same age and for categorization. PMID:23950877

  12. Conservation status of a threatened tree species: establishing a baseline for restoration of Juglans cinerea L

    Science.gov (United States)

    Amanda M. Parks; Michael A. Jenkins; Keith E. Woeste; Michael E. Ostry

    2013-01-01

    To mitigate the loss of native tree species threatened by non-native pathogens, managers need to better understand the conservation status of remaining populations and the conditions that favor successful regeneration. Populations of Juglans cinerea L. (butternut), a wide-ranging riparian species, have been devastated by butternut canker, a disease...

  13. Native Peoples-Native Homelands Climate Change Workshop: Lessons Learned

    Science.gov (United States)

    Maynard, N. G.

    2003-12-01

    The Native Peoples-Native Homelands Climate Change Workshop was held on October 28 through November 01, 1998, as part of a series of workshops being held around the U.S. to improve the understanding of the potential consequences of climate variability and change for the Nation. This workshop was specifically designed by Native Peoples to examine the impacts of climate change and extreme weather variability on Native Peoples and Native Homelands from an indigenous cultural and spiritual perspective and to develop recommendations as well as identify potential response actions. The workshop brought together interested Native Peoples, representatives of Tribal governments, traditional elders, Tribal leaders, natural resource managers, Tribal College faculty and students, and climate scientists from government agencies and universities. It is clear that Tribal colleges and universities play a unique and critical role in the success of these emerging partnerships for decision-making in addition to the important education function for both Native and non-Native communities such as serving as a culturally- appropriate vehicle for access, analysis, control, and protection of indigenous cultural and intellectual property. During the discussions between scientists and policy-makers from both Native and non-Native communities, a number of important lessons emerged which are key to building more effective partnerships between Native and non-Native communities for collaboration and decision-making for a more sustainable future. This talk summarizes the key issues, recommendations, and lessons learned during this workshop.

  14. Intelligibility of native and non-native Dutch Speech

    NARCIS (Netherlands)

    Wijngaarden, S.J. van

    2001-01-01

    The intelligibility of speech is known to be lower if the speaker is non-native instead of native for the given language. This study is aimed at quantifying the overall degradation due to limitations of non-native speakers of Dutch, specifically of Dutch-speaking Americans who have lived in the Neth

  15. Speech intelligibility of native and non-native speech

    NARCIS (Netherlands)

    Wijngaarden, S.J. van

    1999-01-01

    The intelligibility of speech is known to be lower if the talker is non-native instead of native for the given language. This study is aimed at quantifying the overall degradation due to acoustic-phonetic limitations of non-native talkers of Dutch, specifically of Dutch-speaking Americans who have l

  16. Biology, ecology, and management of Xylosandrus spp. ambrosia beetles (Coleoptera: Curculionidae: Scolytinae) in ornamental tree nurseries

    Science.gov (United States)

    Xylosandrus germanus (Blandford) and Xylosandrus crassiusculus (Motschulsky) (Coleoptera: Curculionidae: Scolytinae) are two of the most damaging non-native ambrosia beetle pests in ornamental tree nurseries. Adult females tunnel into the stems and branches of host trees to create galleries with bro...

  17. Mycorrhizal fungi and trees - a successful reforestation alternative for mineland reclamation

    Science.gov (United States)

    C. E. Cordell; L. F. Mans; D. H. Marx

    2002-01-01

    Successful consistent revegetation of drastically disturbed mine sites (in other words, acid coal spoils and mineral waste dumps) throughout the United States and several foreign countries has been achieved by using the biological "tools" - tree seedlings, native shrubs and grass species inoculated with mycorrhizal fungi. These trees and shrubs are custom-...

  18. Effects of exotic invasive trees on nitrogen cycling: a case study in Central Spain

    NARCIS (Netherlands)

    Castro-Diez, P.; González-Muñoz, N.; Alonso, A.; Gallardo, A.; Poorter, L.

    2009-01-01

    We assess the hypothesis that rates of nitrogen transformations in the soil are altered upon replacement of native by exotic trees, differing in litter properties. Ailanthus altissima and Robinia pseudoacacia, two common exotic trees naturalized in the Iberian Peninsula, were compared with the

  19. Native Americans' Interest in Horticulture.

    Science.gov (United States)

    Meyer, Mary Hockenberry

    1999-01-01

    Focus groups arranged by local Native American Master Gardeners on two Minnesota reservations determined community interest in extension-horticulture programs. Topics of interest included food preservation and historical Native-American uses of plants. (SK)

  20. Native Prairie Adaptive Management (NPAM)

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — NPAM is a framework for guiding annual decisions about the management of Service‐owned native prairie parcels that are prone to invasions by non‐native grasses,...

  1. Spanning Tree Problem

    Directory of Open Access Journals (Sweden)

    Yen Hung Chen

    2012-01-01

    minimum cost spanning tree T in G such that the total weight in T is at most a given bound B. In this paper, we present two polynomial time approximation schemes (PTASs for the constrained minimum spanning tree problem.

  2. Making Tree Ensembles Interpretable

    OpenAIRE

    Hara, Satoshi; Hayashi, Kohei

    2016-01-01

    Tree ensembles, such as random forest and boosted trees, are renowned for their high prediction performance, whereas their interpretability is critically limited. In this paper, we propose a post processing method that improves the model interpretability of tree ensembles. After learning a complex tree ensembles in a standard way, we approximate it by a simpler model that is interpretable for human. To obtain the simpler model, we derive the EM algorithm minimizing the KL divergence from the ...

  3. Embeddings of Iteration Trees

    OpenAIRE

    Mitchell, William

    1992-01-01

    This paper, dating from May 1991, contains preliminary (and unpublishable) notes on investigations about iteration trees. They will be of interest only to the specialist. In the first two sections I define notions of support and embeddings for tree iterations, proving for example that every tree iteration is a direct limit of finite tree iterations. This is a generalization to models with extenders of basic ideas of iterated ultrapowers using only ultrapowers. In the final section (which is m...

  4. The invasive alien tree Falcataria moluccana: its impacts and management

    Science.gov (United States)

    Flint Hughes; Tracy Johnson; Amanda Uowolo

    2013-01-01

    Falcataria moluccana (Miq.) Barneby and Grimes is a large tree that has become invasive in forests and developed landscapes across many Pacific islands. A fast-growing nitrogenfixing species, it transforms invaded ecosystems by dramatically increasing nutrient inputs, suppressing native species and facilitating invasion by other weeds. Individuals rapidly reach heights...

  5. Who Stole Native American Studies?

    Science.gov (United States)

    Cook-Lynn, Elizabeth

    1997-01-01

    Native American Studies has failed to develop into an academic discipline because of the continued influence of postcolonial theories, attempts to discredit Native American scholars, politically determined research agendas, and the ideology of the "New Historicism." Native American Studies must seek autonomy from other opportunistic…

  6. Who Stole Native American Studies?

    Science.gov (United States)

    Cook-Lynn, Elizabeth

    1997-01-01

    Native American Studies has failed to develop into an academic discipline because of the continued influence of postcolonial theories, attempts to discredit Native American scholars, politically determined research agendas, and the ideology of the "New Historicism." Native American Studies must seek autonomy from other opportunistic…

  7. Digital Natives or Digital Tribes?

    Science.gov (United States)

    Watson, Ian Robert

    2013-01-01

    This research builds upon the discourse surrounding digital natives. A literature review into the digital native phenomena was undertaken and found that researchers are beginning to identify the digital native as not one cohesive group but of individuals influenced by other factors. Primary research by means of questionnaire survey of technologies…

  8. Covering tree with stars

    DEFF Research Database (Denmark)

    Baumbach, Jan; Guo, Jian-Ying; Ibragimov, Rashid

    2013-01-01

    We study the tree edit distance problem with edge deletions and edge insertions as edit operations. We reformulate a special case of this problem as Covering Tree with Stars (CTS): given a tree T and a set of stars, can we connect the stars in by adding edges between them such that the resulting ...

  9. Covering tree with stars

    DEFF Research Database (Denmark)

    Baumbach, Jan; Guo, Jiong; Ibragimov, Rashid

    2015-01-01

    We study the tree edit distance problem with edge deletions and edge insertions as edit operations. We reformulate a special case of this problem as Covering Tree with Stars (CTS): given a tree T and a set of stars, can we connect the stars in by adding edges between them such that the resulting ...

  10. Macro tree transducers

    NARCIS (Netherlands)

    Engelfriet, Joost; Vogler, Heiko

    1985-01-01

    Macro tree transducers are a combination of top-down tree transducers and macro grammars. They serve as a model for syntax-directed semantics in which context information can be handled. In this paper the formal model of macro tree transducers is studied by investigating typical automata theoretical

  11. Winter Birch Trees

    Science.gov (United States)

    Sweeney, Debra; Rounds, Judy

    2011-01-01

    Trees are great inspiration for artists. Many art teachers find themselves inspired and maybe somewhat obsessed with the natural beauty and elegance of the lofty tree, and how it changes through the seasons. One such tree that grows in several regions and always looks magnificent, regardless of the time of year, is the birch. In this article, the…

  12. Total well dominated trees

    DEFF Research Database (Denmark)

    Finbow, Arthur; Frendrup, Allan; Vestergaard, Preben D.

    cardinality then G is a total well dominated graph. In this paper we study composition and decomposition of total well dominated trees. By a reversible process we prove that any total well dominated tree can both be reduced to and constructed from a family of three small trees....

  13. The Wish Tree Project

    Science.gov (United States)

    Brooks, Sarah DeWitt

    2010-01-01

    This article describes the author's experience in implementing a Wish Tree project in her school in an effort to bring the school community together with a positive art-making experience during a potentially stressful time. The concept of a wish tree is simple: plant a tree; provide tags and pencils for writing wishes; and encourage everyone to…

  14. The Wish Tree Project

    Science.gov (United States)

    Brooks, Sarah DeWitt

    2010-01-01

    This article describes the author's experience in implementing a Wish Tree project in her school in an effort to bring the school community together with a positive art-making experience during a potentially stressful time. The concept of a wish tree is simple: plant a tree; provide tags and pencils for writing wishes; and encourage everyone to…

  15. Macro tree transducers

    NARCIS (Netherlands)

    Engelfriet, Joost; Vogler, Heiko

    1985-01-01

    Macro tree transducers are a combination of top-down tree transducers and macro grammars. They serve as a model for syntax-directed semantics in which context information can be handled. In this paper the formal model of macro tree transducers is studied by investigating typical automata theoretical

  16. Effects of Invasive Winter Moth Defoliation on Tree Radial Growth in Eastern Massachusetts, USA

    OpenAIRE

    Simmons, Michael J.; Lee, Thomas D.; Ducey, Mark J; Elkinton, Joseph S.; Boettner, George H.; Kevin J Dodds

    2014-01-01

    Winter moth, Operophtera brumata L. (Lepidoptera: Geometridae), has been defoliating hardwood trees in eastern Massachusetts since the 1990s. Native to Europe, winter moth has also been detected in Rhode Island, Connecticut, eastern Long Island (NY), New Hampshire, and Maine. Individual tree impacts of winter moth defoliation in New England are currently unknown. Using dendroecological techniques, this study related annual radial growth of individual host (Quercus spp. and Acer spp.) trees to...

  17. Early Growth Assessment of Selected Exotic and Indigenous Tree Species in Nigeria

    OpenAIRE

    2014-01-01

    Background and Purpose: Nigeria is greatly endowed with numerous tree species of which majority of them are native while few are exotic. Report shows that high percentage of man-made forests in the country is dominated with exotic species. This culminated from the assumption that exotic trees are fast growing. However, this study investigated the growth of indigenous trees in tandem with that of exotic species with a purpose to clarify the assumption about the growth and conservation of indig...

  18. A complementary strategy for the conservation of native forest tree species: retrieval and conservation of threatened ecotypes Estratégia complementar para conservação de espécies florestais nativas: resgate e conservação de ecótipos ameaçados

    Directory of Open Access Journals (Sweden)

    Jarbas Yukio Shimizu

    2010-06-01

    Full Text Available Deforestation has become rampant in recent years in Brazil and has affected all biomes where many
    species are threatened to extinction due to destruction natural habitats. Government initiatives to hinder the
    chain of destruction include two main lines of action: to establish conservation units (parks, reserves and
    others; and programs to encourage plantation of native tree species for reclamation of degraded ecosystems, restoration of forests on permanent protection areas (riparian, and steep slope environments, and establishment of “legal reserves” (a mandatory forest reserve on at least 20% of the land area. Conservation units are effective
    in conserving natural ecosystems. However, they are of limited value for the conservation of ecotypes, since
    their effectiveness is restricted to within their physical boundaries. Since the majority of ecotypes with critical
    adaptive value are found outside the conservation units, complementary measures to encompass these variants are needed. The most promising strategy includes active participation of rural land owners, especially small land holders, since they are settled throughout the country (outside the conservation units. An important aspect of the strategy is to prevent movement of seeds and seedlings over great distances from their origins so that their adaptive traits to specific sites are preserved.A devastação das florestas brasileiras vem tomando proporções alarmantes em todos os biomas,
    colocando muitas espécies de microorganismos, animais e plantas sob risco de extinção devido à descaracterização do habitat. Medidas governamentais contra esse processo de destruição incluem o estabelecimento de unidades de conservação e os programas de plantio de espécies nativas com objetivos variados, como a recuperação de
    ecossistemas degradados e o estabelecimento de Reservas Legais, Áreas de Proteção Permanente e outros. As unidades de

  19. Trees in Lhasa

    Institute of Scientific and Technical Information of China (English)

    Degyi

    2008-01-01

    Trees are flourishing in Lhasa wherever the history exists. There is such a man. He has already been through cus-toms after his annual trek to Lhasa, which he has been doing for over twenty years in succession to visit his tree.Although he has been making this journey for so long,it is neither to visit friends or family,nor is it his hometown.It is a tree that is tied so profoundly to his heart.When the wind blows fiercely on the bare tree and winter snow falls,he stands be-fore the tree with tears of jo...

  20. Distributed Contour Trees

    Energy Technology Data Exchange (ETDEWEB)

    Morozov, Dmitriy; Weber, Gunther H.

    2014-03-31

    Topological techniques provide robust tools for data analysis. They are used, for example, for feature extraction, for data de-noising, and for comparison of data sets. This chapter concerns contour trees, a topological descriptor that records the connectivity of the isosurfaces of scalar functions. These trees are fundamental to analysis and visualization of physical phenomena modeled by real-valued measurements. We study the parallel analysis of contour trees. After describing a particular representation of a contour tree, called local{global representation, we illustrate how di erent problems that rely on contour trees can be solved in parallel with minimal communication.

  1. Growth of a Pine Tree

    Science.gov (United States)

    Rollinson, Susan Wells

    2012-01-01

    The growth of a pine tree is examined by preparing "tree cookies" (cross-sectional disks) between whorls of branches. The use of Christmas trees allows the tree cookies to be obtained with inexpensive, commonly available tools. Students use the tree cookies to investigate the annual growth of the tree and how it corresponds to the number of whorls…

  2. Growth of a Pine Tree

    Science.gov (United States)

    Rollinson, Susan Wells

    2012-01-01

    The growth of a pine tree is examined by preparing "tree cookies" (cross-sectional disks) between whorls of branches. The use of Christmas trees allows the tree cookies to be obtained with inexpensive, commonly available tools. Students use the tree cookies to investigate the annual growth of the tree and how it corresponds to the number of whorls…

  3. Asthma and American Indians/Alaska Natives

    Science.gov (United States)

    ... Minority Population Profiles > American Indian/Alaska Native > Asthma Asthma and American Indians/Alaska Natives In 2014, 218, ... Native American adults reported that they currently have asthma. American Indian/Alaska Native children are 30% more ...

  4. Stroke and Native Hawaiians/Pacific Islanders

    Science.gov (United States)

    ... Population Profiles > Native Hawaiian/Other Pacific Islander > Stroke Stroke and Native Hawaiians/Pacific Islanders Native Hawaiians/Pacific ... non-Hispanic white adults to die from a stroke in 2010. In general, Native Hawaiian/Pacific Islander ...

  5. Programming macro tree transducers

    DEFF Research Database (Denmark)

    Bahr, Patrick; Day, Laurence E.

    2013-01-01

    A tree transducer is a set of mutually recursive functions transforming an input tree into an output tree. Macro tree transducers extend this recursion scheme by allowing each function to be defined in terms of an arbitrary number of accumulation parameters. In this paper, we show how macro tree...... transducers can be concisely represented in Haskell, and demonstrate the benefits of utilising such an approach with a number of examples. In particular, tree transducers afford a modular programming style as they can be easily composed and manipulated. Our Haskell representation generalises the original...... definition of (macro) tree transducers, abolishing a restriction on finite state spaces. However, as we demonstrate, this generalisation does not affect compositionality....

  6. Programming macro tree transducers

    DEFF Research Database (Denmark)

    Bahr, Patrick; Day, Laurence E.

    2013-01-01

    A tree transducer is a set of mutually recursive functions transforming an input tree into an output tree. Macro tree transducers extend this recursion scheme by allowing each function to be defined in terms of an arbitrary number of accumulation parameters. In this paper, we show how macro tree...... transducers can be concisely represented in Haskell, and demonstrate the benefits of utilising such an approach with a number of examples. In particular, tree transducers afford a modular programming style as they can be easily composed and manipulated. Our Haskell representation generalises the original...... definition of (macro) tree transducers, abolishing a restriction on finite state spaces. However, as we demonstrate, this generalisation does not affect compositionality....

  7. Nitrogen fixation in trees - 1

    Energy Technology Data Exchange (ETDEWEB)

    Dobereiner, J.; Gauthier, D.L.; Diem, H.G.; Dommergues, Y.R.; Bonetti, R.; Oliveira, L.A.; Magalhaes, F.M.M.; Faria, S.M. de; Franco, A.A.; Menandro, M.S.

    1984-01-01

    Six papers are presented from the symposium. Dobereiner, J.; Nodulation and nitrogen fixation in leguminous trees, 83-90, (15 ref.), reviews studies on Brazilian species. Gauthier, D.L., Diem, H.G., Dommergues, Y.R., Tropical and subtropical actinorhizal plants, 119-136, (Refs. 50), reports on studies on Casuarinaceae. Bonetti, R., Oliveira, L.A., Magalhaes, F.M.M.; Rhizobium populations and occurrence of VA mycorrhizae in plantations of forest trees, 137-142, (Refs. 15), studies Amazonia stands of Cedrelinga catenaeformis, Calophyllum brasiliense, Dipteryx odorata, D. potiphylla, Carapa guianensis, Goupia glabra, Tabebuia serratifolia, Clarisia racemosa, Pithecellobium racemosum, Vouacapoua pallidior, Eperua bijuga, and Diplotropis species. Nodulation was observed in Cedrelinga catenaeformis and V. pallidior. Faria, S.M. de, Franco, A.A., Menandro, M.S., Jesus, R.M. de, Baitello, J.B.; Aguiar, O.T. de, Doebereiner, J; survey of nodulation in leguminous tree species native to southeastern Brazil, 143-153, (Refs. 7), reports on 119 species, with first reports of nodulation in the genera Bowdichia, Poecilanthe, Melanoxylon, Moldenhaurea (Moldenhawera), and Pseudosamanea. Gaiad, S., Carpanezzi, A.A.; Occurrence of Rhizobium in Leguminosae of silvicultural interest for south Brazil, 155-158, (Refs. 2). Nodulation is reported in Mimosa scabrella, Acacia mearnsii, A. longifolia various trinervis, Enterolobium contortisiliquum, and Erythrina falcata. Magalhaes, L.M.S., Blum, W.E.H., Nodulation and growth of Cedrelinga catanaeformis in experimental stands in the Manaus region - Amazonas, 159-164, (Refs. 5). Results indicate that C. catenaeformis can be used in degraded areas of very low soil fertility.

  8. The radial distribution of [sup 90]Sr and [sup 137]Cs in trees

    Energy Technology Data Exchange (ETDEWEB)

    Nomoshima, N. (Kyushu Univ., Fukuoka (Japan). Faculty of Science); Bondietti, E.A. (Oak Ridge National Lab., TN (United States). Environmental Sciences Div.)

    1994-01-01

    The distributions of [sup 90]Sr and [sup 137]Cs in tree trunks were measured for eight species. The concentration of [sup 137]Cs was relatively uniform in the wood xylem and did not show any correlation with the temporal record of cumulative deposition of fallout in the northern hemisphere, indicating that [sup 137]Cs was mobile in the wood xylem. The distributions of [sup 90]Sr were classified into three groups. All of the gymnosperms - red spruce, eastern hemlock and white pine - showed a maximum [sup 90]Sr specific activity in rings formed in the 1960s and the overall distribution was closely associated with the temporal record of the cumulative deposition of fallout. Three of five angiosperms -hickory, elm and American beech - showed similar distributions to the gymnosperms except that the maximum [sup 90]Sr specific activity corresponded to the 1970s. The other two angiosperms - yellow poplar and sugar maple - did not show any correlation with the cumulative fallout deposition. The radial distribution of [sup 90]Sr in gymnosperms was simulated considering a steady-state cycling of [sup 90]Sr in the forest ecosystem. The model suggested that a few per cent of stable Sr are replaced annually in the nutrient pool of gymnosperms. (Author).

  9. Native and exotic woody vegetation communities in domestic gardens in relation to social and environmental factors

    Directory of Open Access Journals (Sweden)

    Yolanda M. van Heezik

    2014-12-01

    Full Text Available Vegetation in private gardens contributes significantly to plant species richness and vegetation volume across urban areas. Drivers of garden diversity and structure are complex, reflecting the diversity of social, cultural, and socioeconomic characteristics of the householders who manage their gardens, as well as their predecessors. Here we investigate the woodiness of gardens, and focus on (1 the prevalence of native versus exotic woody plants and (2 the influence of characteristics of garden owners, the gardens, and their proximity to neighborhood green spaces to identify the degree to which these factors explain patterns in native and exotic woody species communities in entire (back and front gardens in southern temperate New Zealand. We found few consistent patterns in structure in woody species community composition. Outlying gardens were characterized by low species richness and abundance. Thirty-seven species commonly occurred across most gardens: most of these were exotic. Twelve native species were common throughout most gardens. There was significant but weak matching to social and environmental variables: vegetated area, species knowledge, and education explained pattern in native communities, whereas vegetated area, species knowledge, and householder age explained variation in exotic communities. Native trees > 5 m tall occurred in only 58% of gardens. Tall tree density was 10/ha, and 29% of gardens lacked any trees > 5 m. Tree presence was weakly (positively associated with extent and proximity of neighborhood green space. We suggest that the legacy of previous owners' gardening practices is important to consider when identifying drivers of garden plant community structure.

  10. Pattern Avoidance in Ternary Trees

    CERN Document Server

    Gabriel, Nathan; Pudwell, Lara; Tay, Samuel

    2011-01-01

    This paper considers the enumeration of ternary trees (i.e. rooted ordered trees in which each vertex has 0 or 3 children) avoiding a contiguous ternary tree pattern. We begin by finding recurrence relations for several simple tree patterns; then, for more complex trees, we compute generating functions by extending a known algorithm for pattern-avoiding binary trees. Next, we present an alternate one-dimensional notation for trees which we use to find bijections that explain why certain pairs of tree patterns yield the same avoidance generating function. Finally, we compare our bijections to known "replacement rules" for binary trees and generalize these bijections to a larger class of trees.

  11. Setting Priorities for Monitoring and Managing Non-native Plants: Toward a Practical Approach

    Science.gov (United States)

    Koch, Christiane; Jeschke, Jonathan M.; Overbeck, Gerhard E.; Kollmann, Johannes

    2016-09-01

    Land managers face the challenge to set priorities in monitoring and managing non-native plant species, as resources are limited and not all non-natives become invasive. Existing frameworks that have been proposed to rank non-native species require extensive information on their distribution, abundance, and impact. This information is difficult to obtain and often not available for many species and regions. National watch or priority lists are helpful, but it is questionable whether they provide sufficient information for environmental management on a regional scale. We therefore propose a decision tree that ranks species based on more simple albeit robust information, but still provides reliable management recommendations. To test the decision tree, we collected and evaluated distribution data from non-native plants in highland grasslands of Southern Brazil. We compared the results with a national list from the Brazilian Invasive Species Database for the state to discuss advantages and disadvantages of the different approaches on a regional scale. Out of 38 non-native species found, only four were also present on the national list. If management would solely rely on this list, many species that were identified as spreading based on the decision tree would go unnoticed. With the suggested scheme, it is possible to assign species to active management, to monitoring, or further evaluation. While national lists are certainly important, management on a regional scale should employ additional tools that adequately consider the actual risk of non-natives to become invasive.

  12. Aquatic macroinvertebrate responses to native and non-native predators

    Directory of Open Access Journals (Sweden)

    Haddaway N. R.

    2014-01-01

    Full Text Available Non-native species can profoundly affect native ecosystems through trophic interactions with native species. Native prey may respond differently to non-native versus native predators since they lack prior experience. Here we investigate antipredator responses of two common freshwater macroinvertebrates, Gammarus pulex and Potamopyrgus jenkinsi, to olfactory cues from three predators; sympatric native fish (Gasterosteus aculeatus, sympatric native crayfish (Austropotamobius pallipes, and novel invasive crayfish (Pacifastacus leniusculus. G. pulex responded differently to fish and crayfish; showing enhanced locomotion in response to fish, but a preference for the dark over the light in response to the crayfish. P.jenkinsi showed increased vertical migration in response to all three predator cues relative to controls. These different responses to fish and crayfish are hypothesised to reflect the predators’ differing predation types; benthic for crayfish and pelagic for fish. However, we found no difference in response to native versus invasive crayfish, indicating that prey naiveté is unlikely to drive the impacts of invasive crayfish. The Predator Recognition Continuum Hypothesis proposes that benefits of generalisable predator recognition outweigh costs when predators are diverse. Generalised responses of prey as observed here will be adaptive in the presence of an invader, and may reduce novel predators’ potential impacts.

  13. Bayesian Rose Trees

    CERN Document Server

    Blundell, Charles; Heller, Katherine A

    2012-01-01

    Hierarchical structure is ubiquitous in data across many domains. There are many hier- archical clustering methods, frequently used by domain experts, which strive to discover this structure. However, most of these meth- ods limit discoverable hierarchies to those with binary branching structure. This lim- itation, while computationally convenient, is often undesirable. In this paper we ex- plore a Bayesian hierarchical clustering algo- rithm that can produce trees with arbitrary branching structure at each node, known as rose trees. We interpret these trees as mixtures over partitions of a data set, and use a computationally efficient, greedy ag- glomerative algorithm to find the rose trees which have high marginal likelihood given the data. Lastly, we perform experiments which demonstrate that rose trees are better models of data than the typical binary trees returned by other hierarchical clustering algorithms.

  14. The valuative tree

    CERN Document Server

    Favre, Charles

    2004-01-01

    This volume is devoted to a beautiful object, called the valuative tree and designed as a powerful tool for the study of singularities in two complex dimensions. Its intricate yet manageable structure can be analyzed by both algebraic and geometric means. Many types of singularities, including those of curves, ideals, and plurisubharmonic functions, can be encoded in terms of positive measures on the valuative tree. The construction of these measures uses a natural tree Laplace operator of independent interest.

  15. Comparison of galled trees.

    Science.gov (United States)

    Cardona, Gabriel; Llabrés, Mercè; Rosselló, Francesc; Valiente, Gabriel

    2011-01-01

    Galled trees, directed acyclic graphs that model evolutionary histories with isolated hybridization events, have become very popular due to both their biological significance and the existence of polynomial-time algorithms for their reconstruction. In this paper, we establish to which extent several distance measures for the comparison of evolutionary networks are metrics for galled trees, and hence, when they can be safely used to evaluate galled tree reconstruction methods.

  16. Traditional West Coast Native Medicine

    OpenAIRE

    Deagle, George

    1988-01-01

    An important part of the complex culture of the Native people of Canada's Pacific coast is the traditional system of medicine each culture has developed. Population loss from epidemics and the influence of dominant European cultures has resulted in loss of many aspects of traditional medicine. Although some Native practices are potentially hazardous, continuation of traditional approaches to illness remains an important part of health care for many Native people. The use of “devil's club” pla...

  17. A theory of game trees, based on solution trees

    NARCIS (Netherlands)

    W.H.L.M. Pijls (Wim); A. de Bruin (Arie); A. Plaat (Aske)

    1996-01-01

    textabstractIn this paper a complete theory of game tree algorithms is presented, entirely based upon the notion of a solution tree. Two types of solution trees are distinguished: max and min solution trees respectively. We show that most game tree algorithms construct a superposition of a max and a

  18. A theory of game trees, based on solution trees

    NARCIS (Netherlands)

    W.H.L.M. Pijls (Wim); A. de Bruin (Arie); A. Plaat (Aske)

    1996-01-01

    textabstractIn this paper a complete theory of game tree algorithms is presented, entirely based upon the notion of a solution tree. Two types of solution trees are distinguished: max and min solution trees respectively. We show that most game tree algorithms construct a superposition of a max and a

  19. D2-tree

    DEFF Research Database (Denmark)

    Brodal, Gerth Stølting; Sioutas, Spyros; Pantazos, Kostas;

    2015-01-01

    We present a new overlay, called the Deterministic Decentralized tree (D2-tree). The D2-tree compares favorably to other overlays for the following reasons: (a) it provides matching and better complexities, which are deterministic for the supported operations; (b) the management of nodes (peers......-balancing scheme of elements into nodes is deterministic and general enough to be applied to other hierarchical tree-based overlays. This load-balancing mechanism is based on an innovative lazy weight-balancing mechanism, which is interesting in its own right....

  20. Symmetric M-tree

    CERN Document Server

    Sexton, Alan P

    2010-01-01

    The M-tree is a paged, dynamically balanced metric access method that responds gracefully to the insertion of new objects. To date, no algorithm has been published for the corresponding Delete operation. We believe this to be non-trivial because of the design of the M-tree's Insert algorithm. We propose a modification to Insert that overcomes this problem and give the corresponding Delete algorithm. The performance of the tree is comparable to the M-tree and offers additional benefits in terms of supported operations, which we briefly discuss.

  1. A parallel buffer tree

    DEFF Research Database (Denmark)

    Sitchinava, Nodar; Zeh, Norbert

    2012-01-01

    We present the parallel buffer tree, a parallel external memory (PEM) data structure for batched search problems. This data structure is a non-trivial extension of Arge's sequential buffer tree to a private-cache multiprocessor environment and reduces the number of I/O operations by the number...... of available processor cores compared to its sequential counterpart, thereby taking full advantage of multicore parallelism. The parallel buffer tree is a search tree data structure that supports the batched parallel processing of a sequence of N insertions, deletions, membership queries, and range queries...

  2. Native Speakers' Perception of Non-Native English Speech

    Science.gov (United States)

    Jaber, Maysa; Hussein, Riyad F.

    2011-01-01

    This study is aimed at investigating the rating and intelligibility of different non-native varieties of English, namely French English, Japanese English and Jordanian English by native English speakers and their attitudes towards these foreign accents. To achieve the goals of this study, the researchers used a web-based questionnaire which…

  3. Physical and chemical characterization of biochars produced from coppiced wood of thirteen tree species for use in horticultural substrates

    Science.gov (United States)

    Seven-year-old coppiced shoots from thirteen species of native and non-native trees and shrubs were harvested, dried, and were pyrolyzed to produce biochars for potential use in horticultural substrates. Several chemical and physical characteristics of the biochars were determined. There were slight...

  4. Managing Tree Diversity: A Comparison of Suburban Development in Two Canadian Cities

    Directory of Open Access Journals (Sweden)

    Sophie A. Nitoslawski

    2016-05-01

    Full Text Available Is (suburban forest diversity shaped by previous land use? This study was designed to quantitatively assess the impacts of subdivision development on urban tree-species composition in two Canadian cities: Halifax, Nova Scotia, and London, Ontario. The main goal was to determine whether cities with contrasting pre-urbanized or pre-settlement landscapes—woodlands in Halifax and agricultural fields in London—also revealed differences in urban tree diversity losses and/or gains due to urbanization. In each city, four residential neighbourhoods representing two age categories, older and newer (40–50 years, <15 years, were examined and trees on three land types were sampled: public (street, private (residential, and remnant (woodland. All public street trees within the chosen neighbourhoods were inventoried and approximately 10% of the residential property lots were sampled randomly. Plots were examined in remnant forests in or near each city, representing the original forest habitats prior to agricultural and/or urban landscape transformations. Diameter at breast height, species richness and evenness, and proportions of native and non-native trees were measured. In both cities, streetscapes in newer neighbourhoods exhibit greater species richness and evenness, and are characterized by substantially more native trees. Despite this trend, developers and home owners continue to intensively plant non-native species on newer and smaller property lots. Older neighbourhoods in Halifax containing remnant forest stands hold the greatest number of native trees on private property, alluding to the importance of residual forest buffers and patches in promoting naturalness in the private urban forest. These results suggest that identifying and quantifying flows of species between green spaces during and after development is valuable in order to effectively promote native species establishment and enhance overall urban forest diversity.

  5. The tree BVOC index

    Science.gov (United States)

    J.R. Simpson; E.G. McPherson

    2011-01-01

    Urban trees can produce a number of benefits, among them improved air quality. Biogenic volatile organic compounds (BVOCs) emitted by some species are ozone precursors. Modifying future tree planting to favor lower-emitting species can reduce these emissions and aid air management districts in meeting federally mandated emissions reductions for these compounds. Changes...

  6. Matching Subsequences in Trees

    DEFF Research Database (Denmark)

    Bille, Philip; Gørtz, Inge Li

    2009-01-01

    Given two rooted, labeled trees P and T the tree path subsequence problem is to determine which paths in P are subsequences of which paths in T. Here a path begins at the root and ends at a leaf. In this paper we propose this problem as a useful query primitive for XML data, and provide new...

  7. Structural Equation Model Trees

    Science.gov (United States)

    Brandmaier, Andreas M.; von Oertzen, Timo; McArdle, John J.; Lindenberger, Ulman

    2013-01-01

    In the behavioral and social sciences, structural equation models (SEMs) have become widely accepted as a modeling tool for the relation between latent and observed variables. SEMs can be seen as a unification of several multivariate analysis techniques. SEM Trees combine the strengths of SEMs and the decision tree paradigm by building tree…

  8. Tree biology and dendrochemistry

    Science.gov (United States)

    Kevin T. Smith; Walter C. Shortle

    1996-01-01

    Dendrochemistry, the interpretation of elemental analysis of dated tree rings, can provide a temporal record of environmental change. Using the dendrochemical record requires an understanding of tree biology. In this review, we pose four questions concerning assumptions that underlie recent dendrochemical research: 1) Does the chemical composition of the wood directly...

  9. Tree nut oils

    Science.gov (United States)

    The major tree nuts include almonds, Brazil nuts, cashew nuts, hazelnuts, macadamia nuts, pecans, pine nuts, pistachio nuts, and walnuts. Tree nut oils are appreciated in food applications because of their flavors and are generally more expensive than other gourmet oils. Research during the last de...

  10. Native American youth and justice

    Directory of Open Access Journals (Sweden)

    Dr.Sc. Laurence A. French

    2012-12-01

    Full Text Available Youth and delinquency issues have long been problematic among Native Americans groups both on- and off-reservation. This phenomenon is further complicated by the cultural diversity among American Indians and Alaska Natives scattered across the United States. In address these issues, the paper begins with a historical overview of Native American youth. This history presents the long tradition of federal policies that, how well intended, have resulted in discriminatory practices with the most damages attacks being those directed toward the destruction of viable cultural attributes – the same attributes that make Native Americans unique within United States society. Following the historical material, the authors contrast the pervasive Native American aboriginal ethos of harmony with that of Protestant Ethic that dominates the ethos of the larger United States society. In addition to providing general information on Native American crime and delinquency, the paper also provides a case study of Native American justice within the Navajo Nation, the largest tribe, in both size and population, in the United States. The paper concludes with a discussion of issues specific to Native American youth and efforts to address these problems.

  11. Native American Foods and Cookery.

    Science.gov (United States)

    Taylor, Tom; Potter, Eloise F.

    Native Americans had a well-developed agriculture long before the arrival of the Europeans. Three staples--corn, beans, and squash--were supplemented with other gathered plants or cultivated crops such as white potatoes, sweet potatoes, pumpkins, and peanuts. Native Americans had no cows, pigs, or domesticated chickens; they depended almost…

  12. Ohiyesa's Path: Reclaiming Native Education

    Science.gov (United States)

    James, Adrienne Brant; Renville, Tammy

    2012-01-01

    As Natives have assumed increasing authority and responsibility for tribal and federally funded and administered schools, a more balanced and enlightened view is emerging. Notable among these events is the recognition of the critical need to shift emphasis to the untapped heritage of more recently recognized and acknowledged Native American…

  13. Coyote's Eyes: Native Cognition Styles.

    Science.gov (United States)

    Tafoya, Terry

    1982-01-01

    Using a Native American parable, compares the Standard Average European (SAE) world view with the Standard Native American (SNA) world view and the effects they have on education. Points out possible areas of interethnic confusion as a result of these two world views in communication dealing with cognitive schemes. (LC)

  14. Native American Foods and Cookery.

    Science.gov (United States)

    Taylor, Tom; Potter, Eloise F.

    Native Americans had a well-developed agriculture long before the arrival of the Europeans. Three staples--corn, beans, and squash--were supplemented with other gathered plants or cultivated crops such as white potatoes, sweet potatoes, pumpkins, and peanuts. Native Americans had no cows, pigs, or domesticated chickens; they depended almost…

  15. Coded Splitting Tree Protocols

    DEFF Research Database (Denmark)

    Sørensen, Jesper Hemming; Stefanovic, Cedomir; Popovski, Petar

    2013-01-01

    This paper presents a novel approach to multiple access control called coded splitting tree protocol. The approach builds on the known tree splitting protocols, code structure and successive interference cancellation (SIC). Several instances of the tree splitting protocol are initiated, each...... instance is terminated prematurely and subsequently iterated. The combined set of leaves from all the tree instances can then be viewed as a graph code, which is decodable using belief propagation. The main design problem is determining the order of splitting, which enables successful decoding as early...... as possible. Evaluations show that the proposed protocol provides considerable gains over the standard tree splitting protocol applying SIC. The improvement comes at the expense of an increased feedback and receiver complexity....

  16. Ra isotopes in trees: Their application to the estimation of heartwood growth rates and tree ages

    Science.gov (United States)

    Hancock, Gary J.; Murray, Andrew S.; Brunskill, Gregg J.; Argent, Robert M.

    2006-12-01

    The difficulty in estimating growth rates and ages of tropical and warm-temperate tree species is well known. However, this information has many important environmental applications, including the proper management of native forests and calculating uptake and release of atmospheric carbon. We report the activities of Ra isotopes in the heartwood, sapwood and leaves of six tree species, and use the radial distribution of the 228Ra/226Ra activity ratio in the stem of the tree to estimate the rate of accretion of heartwood. A model is presented in which dissolved Ra in groundwater is taken up by tree roots, translocated to sapwood in a chemically mobile (ion-exchangeable) form, and rendered immobile as it is transferred to heartwood. Uptake of 232Th and 230Th (the parents of 228Ra and 226Ra) is negligible. The rate of heartwood accretion is determined from the radioactive decay of 228Ra (half-life 5.8 years) relative to long-lived 226Ra (half-life 1600 years), and is relevant to growth periods of up to 50 years. By extrapolating the heartwood accretion rate to the entire tree ring record the method also appears to provide realistic estimates of tree age. Eight trees were studied (three of known age, 72, 66 and 35 years), including three Australian hardwood eucalypt species, two mangrove species, and a softwood pine (P. radiata). The method indicates that the rate of growth ring formation is species and climate dependent, varying from 0.7 rings yr-1 for a river red gum (E. camaldulensis) to around 3 rings yr-1 for a tropical mangrove (X. mekongensis).

  17. Ecological survey of the native pinewoods of Scotland 1971

    Science.gov (United States)

    Wood, Claire M.; Bunce, Robert G. H.

    2016-05-01

    In 1971, a comprehensive ecological survey of the native pinewoods of Scotland was carried out by the Institute of Terrestrial Ecology. The survey was initiated as a consequence of growing concern about the status of the pinewood resource. Since the twentieth century, this unique habitat is widely recognised, not only by ecologists for its inherent biodiversity but also by the general public for its cultural and amenity value. The survey, utilising demonstrably repeatable methods, collected information on ground flora, soils, forest structure and also general site information from the major 27 sites of the 35 sites identified as truly native pinewoods in Scotland. The results from the survey prompted the organisation of an international symposium in 1975, which set the conservation agenda for the old Caledonian pinewoods. The data collected during the 1971 survey are now publicly available via the following DOI: doi:10/7xb ("Habitat, vegetation, tree and soil data from Native Pinewoods in Scotland, 1971"). Although the data are now 44 years old, the repeatable methods will allow for a resurvey to take place, in order to assess changes in the vegetation, habitats and tree composition in a statistically robust manner.

  18. UV Screening in Native and Non-native Plant Species in the Tropical Alpine: Implications for Climate Change-Driven Migration of Species to Higher Elevations

    Directory of Open Access Journals (Sweden)

    Paul W. Barnes

    2017-08-01

    Full Text Available Ongoing changes in Earth’s climate are shifting the elevation ranges of many plant species with non-native species often experiencing greater expansion into higher elevations than native species. These climate change-induced shifts in distributions inevitably expose plants to novel biotic and abiotic environments, including altered solar ultraviolet (UV-B (280–315 nm radiation regimes. Do the greater migration potentials of non-native species into higher elevations imply that they have more effective UV-protective mechanisms than native species? In this study, we surveyed leaf epidermal UV-A transmittance (TUV A in a diversity of plant species representing different growth forms to test whether native and non-native species growing above 2800 m elevation on Mauna Kea, Hawaii differed in their UV screening capabilities. We further compared the degree to which TUV A varied along an elevation gradient in the native shrub Vaccinium reticulatum and the introduced forb Verbascum thapsus to evaluate whether these species differed in their abilities to adjust their levels of UV screening in response to elevation changes in UV-B. For plants growing in the Mauna Kea alpine/upper subalpine, we found that adaxial TUV A, measured with a UVA-PAM fluorometer, varied significantly among species but did not differ between native (mean = 6.0%; n = 8 and non-native (mean = 5.8%; n = 11 species. When data were pooled across native and non-native taxa, we also found no significant effect of growth form on TUV A, though woody plants (shrubs and trees were represented solely by native species whereas herbaceous growth forms (grasses and forbs were dominated by non-native species. Along an elevation gradient spanning 2600–3800 m, TUV A was variable (mean range = 6.0–11.2% and strongly correlated with elevation and relative biologically effective UV-B in the exotic V. thapsus; however, TUV A was consistently low (3% and did not vary with elevation in the native

  19. Integrating UniTree with the data migration API

    Science.gov (United States)

    Schrodel, David G.

    1994-01-01

    The Data Migration Application Programming Interface (DMAPI) has the potential to allow developers of open systems Hierarchical Storage Management (HSM) products to virtualize native file systems without the requirement to make changes to the underlying operating system. This paper describes advantages of virtualizing native file systems in hierarchical storage management systems, the DMAPI at a high level, what the goals are for the interface, and the integration of the Convex UniTree+HSM with DMAPI along with some of the benefits derived in the resulting product.

  20. Invasions by two non-native insects alter regional forest species composition and successional trajectories

    Science.gov (United States)

    Randall S. Morin; Andrew M. Liebhold

    2015-01-01

    While invasions of individual non-native phytophagous insect species are known to affect growth and mortality of host trees, little is known about how multiple invasions combine to alter forest dynamics over large regions. In this study we integrate geographical data describing historical invasion spread of the hemlock woolly adelgid, Adelges tsugae...

  1. Soil feedback and pathogen activity in Prunus serotina throughout its native range

    NARCIS (Netherlands)

    Reinhart, K.O.; Royo, A.A.; Putten, van der W.H.; Clay, K.

    2005-01-01

    1 Oomycete soil pathogens are known to have a negative effect on Prunus serotina seedling establishment and to promote tree diversity in a deciduous forest in Indiana, USA. Here, we investigate whether negative feedbacks operate widely in its native range in eastern USA. 2 In laboratory experiments,

  2. Do Native Insects and Associated Fungi Limit Non-Native Woodwasp, Sirex noctilio, Survival in a Newly Invaded Environment?

    Science.gov (United States)

    Haavik, Laurel J; Dodds, Kevin J; Allison, Jeremy D

    2015-01-01

    Sirex noctilio F. (Hymenoptera: Siricidae) is an introduced pest of pines (Pinus spp.) in several countries in the Southern Hemisphere. Although S. noctilio is established in North America (first discovered in 2004), it has not been a destructive pest there so far, where forest communities more closely resemble those in its native Eurasian range—where it is not a pest. To investigate the influence of the existing community of associated insects (competitors + natural enemies) and fungi (vectored by insects) on S. noctilio survival in North America, we examined stage-specific mortality factors and their relative importance, generating life tables drawn from experimentally-manipulated and natural cohorts of Sirex spp. (mostly S. noctilio, but some native S. nigricornis F.). For both natural and experimentally-manipulated cohorts, factors which acted during the earliest Sirex life stages, most likely tree resistance and/or competition among fungal associates, were paramount in dictating woodwasp survival. Experimentally-manipulated life tables revealed that protection from the community of associates resulted in a significantly, and substantially larger (>15x) S. noctilio F1 generation than exposure to it. Seventy percent of generation mortality in the exposed cohort was due to tree resistance or unknown causes early in larval development, which could have included competition among other bark- or wood-inhabiting insects and/or their fungal associates. Only 46% of generation mortality in the protected cohort was due to tree resistance and/or unknown causes. Parasitoids, particularly endoparasitoids (Ibalia spp.), showed limited ability to control S. noctilio, and reduced the experimentally-established cohort by only 11%, and natural cohorts an average of 3.4%. The relative importance of tree resistance vs. competition with bark- and wood-borers in reducing S. noctilio survival remains unclear. Tree resistance and/or competition likely contribute more than natural

  3. Do Native Insects and Associated Fungi Limit Non-Native Woodwasp, Sirex noctilio, Survival in a Newly Invaded Environment?

    Directory of Open Access Journals (Sweden)

    Laurel J Haavik

    Full Text Available Sirex noctilio F. (Hymenoptera: Siricidae is an introduced pest of pines (Pinus spp. in several countries in the Southern Hemisphere. Although S. noctilio is established in North America (first discovered in 2004, it has not been a destructive pest there so far, where forest communities more closely resemble those in its native Eurasian range—where it is not a pest. To investigate the influence of the existing community of associated insects (competitors + natural enemies and fungi (vectored by insects on S. noctilio survival in North America, we examined stage-specific mortality factors and their relative importance, generating life tables drawn from experimentally-manipulated and natural cohorts of Sirex spp. (mostly S. noctilio, but some native S. nigricornis F.. For both natural and experimentally-manipulated cohorts, factors which acted during the earliest Sirex life stages, most likely tree resistance and/or competition among fungal associates, were paramount in dictating woodwasp survival. Experimentally-manipulated life tables revealed that protection from the community of associates resulted in a significantly, and substantially larger (>15x S. noctilio F1 generation than exposure to it. Seventy percent of generation mortality in the exposed cohort was due to tree resistance or unknown causes early in larval development, which could have included competition among other bark- or wood-inhabiting insects and/or their fungal associates. Only 46% of generation mortality in the protected cohort was due to tree resistance and/or unknown causes. Parasitoids, particularly endoparasitoids (Ibalia spp., showed limited ability to control S. noctilio, and reduced the experimentally-established cohort by only 11%, and natural cohorts an average of 3.4%. The relative importance of tree resistance vs. competition with bark- and wood-borers in reducing S. noctilio survival remains unclear. Tree resistance and/or competition likely contribute more

  4. Tea tree oil in the treatment of tinea pedis.

    Science.gov (United States)

    Tong, M M; Altman, P M; Barnetson, R S

    1992-01-01

    Tea tree oil (an essential oil derived primarily from the Australian native Melaleuca alternifolia) has been used as a topical antiseptic agent since the early part of this century for a wide variety of skin infections; however, to date, the evidence for its efficacy in fungal infections is still largely anecdotal. One hundred and four patients completed a randomized, double-blind trial to evaluate the efficacy of 10% w/w tea tree oil cream compared with 1% tolnaftate and placebo creams in the treatment of tinea pedis. Significantly more tolnaftate-treated patients (85%) than tea tree oil (30%) and placebo-treated patients (21%) showed conversion to negative culture at the end of therapy (p tea tree oil and placebo groups. All three groups demonstrated improvement in clinical condition based on the four clinical parameters of scaling, inflammation, itching and burning. The tea tree oil group (24/37) and the tolnaftate group (19/33) showed significant improvement in clinical condition when compared to the placebo group (14/34; p = 0.022 and p = 0.018 respectively). Tea tree oil cream (10% w/w) appears to reduce the symptomatology of tinea pedis as effectively as tolnaftate 1% but is no more effective than placebo in achieving a mycological cure. This may be the basis for the popular use of tea tree oil in the treatment of tinea pedis.

  5. Phylogenetic trees in bioinformatics

    Energy Technology Data Exchange (ETDEWEB)

    Burr, Tom L [Los Alamos National Laboratory

    2008-01-01

    Genetic data is often used to infer evolutionary relationships among a collection of viruses, bacteria, animal or plant species, or other operational taxonomic units (OTU). A phylogenetic tree depicts such relationships and provides a visual representation of the estimated branching order of the OTUs. Tree estimation is unique for several reasons, including: the types of data used to represent each OTU; the use ofprobabilistic nucleotide substitution models; the inference goals involving both tree topology and branch length, and the huge number of possible trees for a given sample of a very modest number of OTUs, which implies that fmding the best tree(s) to describe the genetic data for each OTU is computationally demanding. Bioinformatics is too large a field to review here. We focus on that aspect of bioinformatics that includes study of similarities in genetic data from multiple OTUs. Although research questions are diverse, a common underlying challenge is to estimate the evolutionary history of the OTUs. Therefore, this paper reviews the role of phylogenetic tree estimation in bioinformatics, available methods and software, and identifies areas for additional research and development.

  6. Skewed Binary Search Trees

    DEFF Research Database (Denmark)

    Brodal, Gerth Stølting; Moruz, Gabriel

    2006-01-01

    It is well-known that to minimize the number of comparisons a binary search tree should be perfectly balanced. Previous work has shown that a dominating factor over the running time for a search is the number of cache faults performed, and that an appropriate memory layout of a binary search tree...... can reduce the number of cache faults by several hundred percent. Motivated by the fact that during a search branching to the left or right at a node does not necessarily have the same cost, e.g. because of branch prediction schemes, we in this paper study the class of skewed binary search trees....... For all nodes in a skewed binary search tree the ratio between the size of the left subtree and the size of the tree is a fixed constant (a ratio of 1/2 gives perfect balanced trees). In this paper we present an experimental study of various memory layouts of static skewed binary search trees, where each...

  7. Fragmentation trees reloaded.

    Science.gov (United States)

    Böcker, Sebastian; Dührkop, Kai

    2016-01-01

    Untargeted metabolomics commonly uses liquid chromatography mass spectrometry to measure abundances of metabolites; subsequent tandem mass spectrometry is used to derive information about individual compounds. One of the bottlenecks in this experimental setup is the interpretation of fragmentation spectra to accurately and efficiently identify compounds. Fragmentation trees have become a powerful tool for the interpretation of tandem mass spectrometry data of small molecules. These trees are determined from the data using combinatorial optimization, and aim at explaining the experimental data via fragmentation cascades. Fragmentation tree computation does not require spectral or structural databases. To obtain biochemically meaningful trees, one needs an elaborate optimization function (scoring). We present a new scoring for computing fragmentation trees, transforming the combinatorial optimization into a Maximum A Posteriori estimator. We demonstrate the superiority of the new scoring for two tasks: both for the de novo identification of molecular formulas of unknown compounds, and for searching a database for structurally similar compounds, our method SIRIUS 3, performs significantly better than the previous version of our method, as well as other methods for this task. SIRIUS 3 can be a part of an untargeted metabolomics workflow, allowing researchers to investigate unknowns using automated computational methods.Graphical abstractWe present a new scoring for computing fragmentation trees from tandem mass spectrometry data based on Bayesian statistics. The best scoring fragmentation tree most likely explains the molecular formula of the measured parent ion.

  8. Conversion of native terrestrial ecosystems in Hawai‘i to novel grazing systems: a review

    Science.gov (United States)

    Leopold, Christina R.; Hess, Steven C.

    2017-01-01

    The remote oceanic islands of Hawai‘i exemplify the transformative effects that non-native herbivorous mammals can bring to isolated terrestrial ecosystems. We reviewed published literature containing systematically collected, analyzed, and peer-reviewed original data specifically addressing direct effects of non-native hoofed mammals (ungulates) on terrestrial ecosystems, and indirect effects and interactions on ecosystem processes in Hawai‘i. The effects of ungulates on native vegetation and ecosystems were addressed in 58 original studies and mostly showed strong short-term regeneration of dominant native trees and understory ferns after ungulate removal, but unassisted recovery was dependent on the extent of previous degradation. Ungulates were associated with herbivory, bark-stripping, disturbance by hoof action, soil erosion, enhanced nutrient cycling from the interaction of herbivory and grasses, and increased pyrogenicity and competition between native plants and pasture grasses. No studies demonstrated that ungulates benefitted native ecosystems except in short-term fire-risk reduction. However, non-native plants became problematic and continued to proliferate after release from herbivory, including at least 11 species of non-native pasture grasses that had become established prior to ungulate removal. Competition from non-native grasses inhibited native species regeneration where degradation was extensive. These processes have created novel grazing systems which, in some cases, have irreversibly altered Hawaii’s terrestrial ecology. Non-native plant control and outplanting of rarer native species will be necessary for recovery where degradation has been extensive. Lack of unassisted recovery in some locations should not be construed as a reason to not attempt restoration of other ecosystems.

  9. Disentangling the diversity of arboreal ant communities in tropical forest trees.

    Science.gov (United States)

    Klimes, Petr; Fibich, Pavel; Idigel, Cliffson; Rimandai, Maling

    2015-01-01

    Tropical canopies are known for their high abundance and diversity of ants. However, the factors which enable coexistence of so many species in trees, and in particular, the role of foragers in determining local diversity, are not well understood. We censused nesting and foraging arboreal ant communities in two 0.32 ha plots of primary and secondary lowland rainforest in New Guinea and explored their species diversity and composition. Null models were used to test if the records of species foraging (but not nesting) in a tree were dependent on the spatial distribution of nests in surrounding trees. In total, 102 ant species from 389 trees occurred in the primary plot compared with only 50 species from 295 trees in the secondary forest plot. However, there was only a small difference in mean ant richness per tree between primary and secondary forest (3.8 and 3.3 sp. respectively) and considerably lower richness per tree was found only when nests were considered (1.5 sp. in both forests). About half of foraging individuals collected in a tree belonged to species which were not nesting in that tree. Null models showed that the ants foraging but not nesting in a tree are more likely to nest in nearby trees than would be expected at random. The effects of both forest stage and tree size traits were similar regardless of whether only foragers, only nests, or both datasets combined were considered. However, relative abundance distributions of species differed between foraging and nesting communities. The primary forest plot was dominated by native ant species, whereas invasive species were common in secondary forest. This study demonstrates the high contribution of foragers to arboreal ant diversity, indicating an important role of connectivity between trees, and also highlights the importance of primary vegetation for the conservation of native ant communities.

  10. Disentangling the diversity of arboreal ant communities in tropical forest trees.

    Directory of Open Access Journals (Sweden)

    Petr Klimes

    Full Text Available Tropical canopies are known for their high abundance and diversity of ants. However, the factors which enable coexistence of so many species in trees, and in particular, the role of foragers in determining local diversity, are not well understood. We censused nesting and foraging arboreal ant communities in two 0.32 ha plots of primary and secondary lowland rainforest in New Guinea and explored their species diversity and composition. Null models were used to test if the records of species foraging (but not nesting in a tree were dependent on the spatial distribution of nests in surrounding trees. In total, 102 ant species from 389 trees occurred in the primary plot compared with only 50 species from 295 trees in the secondary forest plot. However, there was only a small difference in mean ant richness per tree between primary and secondary forest (3.8 and 3.3 sp. respectively and considerably lower richness per tree was found only when nests were considered (1.5 sp. in both forests. About half of foraging individuals collected in a tree belonged to species which were not nesting in that tree. Null models showed that the ants foraging but not nesting in a tree are more likely to nest in nearby trees than would be expected at random. The effects of both forest stage and tree size traits were similar regardless of whether only foragers, only nests, or both datasets combined were considered. However, relative abundance distributions of species differed between foraging and nesting communities. The primary forest plot was dominated by native ant species, whereas invasive species were common in secondary forest. This study demonstrates the high contribution of foragers to arboreal ant diversity, indicating an important role of connectivity between trees, and also highlights the importance of primary vegetation for the conservation of native ant communities.

  11. Asthma and Native Hawaiians/Pacific Islanders

    Science.gov (United States)

    ... Population Profiles > Native Hawaiian/Other Pacific Islander > Asthma Asthma and Native Hawaiians/Pacific Islanders Native Hawaiians/Pacific Islanders are 70 percent more likely to have asthma as non-Hispanic whites. National data for this ...

  12. Fetal Alcohol Spectrum Disorders among Native Americans

    Science.gov (United States)

    ... ISORDERS A MONG N ATIVE A MERICANS Native American cultures, which encompass American Indian, Alaska Native and Native ... among American Indians: The mythical and real properties. American Indian Culture and Research Journal 18(2):121-143. www. ...

  13. Obesity and Native Hawaiians/Pacific Islanders

    Science.gov (United States)

    ... Population Profiles > Native Hawaiian/Other Pacific Islander > Obesity Obesity and Native Hawaiians/Pacific Islanders Native Hawaiians/Pacific ... youthonline . [Accessed 05/25/2016] HEALTH IMPACT OF OBESITY More than 80 percent of people with type ...

  14. LIMSUP DEVIATIONS ON TREES

    Institute of Scientific and Technical Information of China (English)

    Fan Aihua

    2004-01-01

    The vertices of an infinite locally finite tree T are labelled by a collection of i.i.d. real random variables {Xσ}σ∈T which defines a tree indexed walk Sσ = ∑θ<r≤σXr. We introduce and study the oscillations of the walk:Exact Hausdorff dimension of the set of such ξ 's is calculated. An application is given to study the local variation of Brownian motion. A general limsup deviation problem on trees is also studied.

  15. Native Speakers in Linguistic Imperialism

    DEFF Research Database (Denmark)

    Phillipson, Robert

    2016-01-01

    is recognised as desirable by some British experts, the native speakers in question seldom have this key qualification. This is even the case when the host country (Brunei) aims at bilingual education. It is unlikely that the host countries are getting value for money. Whether the UK and other ‘English...... the linguicism of British pedagogical expertise are generally involved in native speaker export businesses. They underpin a hierarchy with under-qualified native speakers projected as superior to local teachers who are seen as in need of foreign ‘aid’. In view of the British bodies involved openly declaring...

  16. The Rise of native advertising

    Directory of Open Access Journals (Sweden)

    Marius MANIC

    2015-06-01

    Full Text Available Native advertising is described both as a new way for promoters to engage audiences and as a new, clever, source of revenue for publishers and media agencies. The debates around its morality and the need for a wide accepted framework are often viewed as calls for creativity. Aside from the various forms, strategies and the need for clarification, the fact that native advertising works and its revenue estimates increase annually transforms the new type of ad into a clear objective for companies, marketers and publishers. Native advertising stopped being a buzzword and started being a marketing reality.

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

    NARCIS (Netherlands)

    Eilmann, B.; Rigling, A.

    2012-01-01

    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 specie

  18. Generalising tree traversals and tree transformations to DAGs

    DEFF Research Database (Denmark)

    Bahr, Patrick; Axelsson, Emil

    2017-01-01

    We present a recursion scheme based on attribute grammars that can be transparently applied to trees and acyclic graphs. Our recursion scheme allows the programmer to implement a tree traversal or a tree transformation and then apply it to compact graph representations of trees instead...

  19. Injuries caused by animals to young imbuzeiro (Spondias tuberosa Arruda plants in native and degraded caatinga areas

    Directory of Open Access Journals (Sweden)

    Luiza Teixeira de Lima Brito

    2009-12-01

    Full Text Available This study had the objective of evaluating the injuries caused by animals to young imbu tree (Spondias tuberosa Arruda plants in native and degraded Caatinga areas, between the years 1997 and 2002. One thousand imbu tree scions were planted, being 500 in a degraded Caatinga area at the community of Alto do Angico, Petrolina-PE, and 500 in a native Caatinga area at the Caatinga Experimental Station of Embrapa Tropical Semi-Arid, Petrolina-PE. At every 30 days after having planted the scions, data were collected regarding survival and injuries caused by animals to the plants. The results showed that goats are responsible for the reduction on survival rates and for the slow development of young imbu tree in the degraded Caatinga area. In the native Caatinga area, of the collared peccary (Tayassu tajacu and armadillo (Euphractus sexcinctus caused the highest injury levels.

  20. Tea tree oil.

    Science.gov (United States)

    Larson, David; Jacob, Sharon E

    2012-01-01

    Tea tree oil is an increasingly popular ingredient in a variety of household and cosmetic products, including shampoos, massage oils, skin and nail creams, and laundry detergents. Known for its potential antiseptic properties, it has been shown to be active against a variety of bacteria, fungi, viruses, and mites. The oil is extracted from the leaves of the tea tree via steam distillation. This essential oil possesses a sharp camphoraceous odor followed by a menthol-like cooling sensation. Most commonly an ingredient in topical products, it is used at a concentration of 5% to 10%. Even at this concentration, it has been reported to induce contact sensitization and allergic contact dermatitis reactions. In 1999, tea tree oil was added to the North American Contact Dermatitis Group screening panel. The latest prevalence rates suggest that 1.4% of patients referred for patch testing had a positive reaction to tea tree oil.

  1. Tree-like tableaux

    CERN Document Server

    Aval, Jean-Christophe; Nadeau, Philippe

    2011-01-01

    In this work we introduce and study tree-like tableaux, which are certain fillings of Ferrers diagrams in simple bijection with permutation tableaux and alternative tableaux. We exhibit an elementary insertion procedure on our tableaux which gives a clear proof that tableaux of size n are counted by n!, and which moreover respects most of the well-known statistics studied originally on alternative and permutation tableaux. Our insertion procedure allows to define in particular two simple new bijections between tree-like tableaux and permutations: the first one is conceived specifically to respect the generalized pattern 2-31, while the second one respects the underlying tree of a tree-like tableau.

  2. NLCD 2001 - Tree Canopy

    Data.gov (United States)

    Minnesota Department of Natural Resources — The National Land Cover Database 2001 tree canopy layer for Minnesota (mapping zones 39-42, 50-51) was produced through a cooperative project conducted by the...

  3. Full tree harvesting update

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, K.; White, K.

    1981-03-01

    An important harvesting alternative in North America is the Full Tree Method, in which trees are felled and transported to roadside, intermediate or primary landings with limbs and branches intact. The acceptance of Full Tree Systems is due to many factors including: labour productivity and increased demands on the forest for ''new products''. These conditions are shaping the future look for forest Harvesting Systems, but must not be the sole determinants. All harvesting implications, such as those affecting Productivity and silviculture, should be thoroughly understood. This paper does not try to discuss every implication, nor any particular one in depth; its purpose is to highlight those areas requiring consideration and to review several current North American Full Tree Systems. (Refs. 5).

  4. Hot-air drying characteristics and technical parameters optimization of kernel hickory (Carya cathayensis Sarg.)%山核桃坚果热风干燥特性及其工艺参数优化

    Institute of Scientific and Technical Information of China (English)

    朱德泉; 曹成茂; 丁正耀; 刘伟伟; 张念生; 王继先

    2011-01-01

    针对山核桃坚果热风干燥质量难以控制、干后品质差等问题,采用单因素试验方法,研究了热风温度、装载量及风速对山核桃坚果干燥特性的影响.通过3因素5水平的二次回归正交试验,分析了热风温度、装载量及风速与干燥过程单位时间干燥速率、单位质量干燥能耗以及干后物料蛋白质保存率、不饱和脂肪酸保存率、感官品质指标综合分值的关系,建立了二次同归数学模型,分析了3因素对各指标影响的显著性;利用多目标非线性优化方法,确定了山核桃坚果热风干燥的最佳工艺参数组合,即热风温度为72℃,装载量为0.08 kg,风速为65 m/min.在此条件下,单位时间干燥速率为0.458%/min、单位质量干燥能耗为5.986 kWh/kg、蛋白质保存率为92.12%、不饱和脂肪酸保存率为90.65%、感官品质指标综合分值为32.89分,综合评分为0.802.研究结果为山核桃坚果的干燥和工业化生产提供一定的理论依据.%According to the proplems of difficult control for hot-air drying process and poor quality of dried hickory kernels (Carya cathayensis Sarg.), the effects of drying temperature, material load and airflow rate on hot-air drying characteristics of kernels were investigated by the single factor experimental method. The quadratic regression orthogonal experimental method with three factors and five levels for each factor was employed. Drying temperature, material load and airflow rate were the influence factors, and dehydration rate, energy consumption of drying process, protein retention ratio, unsaturated fatty acid retention ratio and synthetic score of sensory quality indicator of dried kernels were the experimental indices. The relationships between the experimental indices and the influence factors were analyzed. The regression mathematical models describing the relations between the experimental indices and the influence factors were established to analyze the

  5. Effects of Patagonian pine forestry on native breeding birds

    Directory of Open Access Journals (Sweden)

    Moises Pescador

    2014-12-01

    Full Text Available Aim of the study: The objective is to assess the influences of the tree stand age and other forestry management practices on species richness, composition, and distribution of the Patagonian pine plantation bird assemblages. Area of Study: The work was carried out in forested plots of Ponderosa pine located at the Lanín National Park (Patagonia, Argentina.Material and Methods: Birds were sampled using 25 m fixed radius point counts, at four plots varying in age, management, and forest structure. Main Results: A total of 2090 individuals belonging to 34 bird species were observed, their numbers vary significantly depending on the different modes of plantation management. The population density of the 14 most abundant bird species was compared among the four plantation plots and ten species don’t show statistically significant differences in their population density among the different forest plots. The California Quail, the White-Crested Elaenia and the Southern House Wren showed higher densities in pine plantations with lower tree densities and fewer cutting treatments. The Diuca Finch had high densities in the younger plantations not subjected to any treatment. Research highlights: Most of these bird species are opportunistic and a few are found more regularly in these non-native woods than in other native forested or afforested areas. Our data suggest that a mixed scenario based on a mosaic of plantation with patches of native deciduous forest may help maximize the bird diversity in the management of northwestern Patagonian plantation landscapes.Keywords: Bird population; diversity; exotic plantations; Patagonia; tree-age.

  6. Fault Tree Handbook

    Science.gov (United States)

    1981-01-01

    to be Evaluated Manufacturer Location Seismic Susceptibility Flood Susceptibility Temperature Humidity Radiation Wear-out Susceptibility Test...For the category " Seismic Susceptibility," we might define several sensitivity levels ranging from no sensitivity to extreme sensitivity, and for more... Hanford Company, Richland, Wash- ington, ARH-ST-l 12, July 1975. 40. W.E. Vesely, "Analysis of Fault Trees by Kinetic Tree Theory," Idaho Nuclear

  7. Type extension trees

    DEFF Research Database (Denmark)

    Jaeger, Manfred

    2006-01-01

    We introduce type extension trees as a formal representation language for complex combinatorial features of relational data. Based on a very simple syntax this language provides a unified framework for expressing features as diverse as embedded subgraphs on the one hand, and marginal counts...... of attribute values on the other. We show by various examples how many existing relational data mining techniques can be expressed as the problem of constructing a type extension tree and a discriminant function....

  8. Type extension trees

    DEFF Research Database (Denmark)

    Jaeger, Manfred

    2006-01-01

    We introduce type extension trees as a formal representation language for complex combinatorial features of relational data. Based on a very simple syntax this language provides a unified framework for expressing features as diverse as embedded subgraphs on the one hand, and marginal counts...... of attribute values on the other. We show by various examples how many existing relational data mining techniques can be expressed as the problem of constructing a type extension tree and a discriminant function....

  9. Multiscale singularity trees

    DEFF Research Database (Denmark)

    Somchaipeng, Kerawit; Sporring, Jon; Johansen, Peter

    2007-01-01

    We propose MultiScale Singularity Trees (MSSTs) as a structure to represent images, and we propose an algorithm for image comparison based on comparing MSSTs. The algorithm is tested on 3 public image databases and compared to 2 state-of-theart methods. We conclude that the computational complexity...... of our algorithm only allows for the comparison of small trees, and that the results of our method are comparable with state-of-the-art using much fewer parameters for image representation....

  10. Tree Improvement Glossary

    DEFF Research Database (Denmark)

    Schmidt, Lars Holger

    Forest tree improvement encompasses a number of scientific and technical areas like floral-, reproductive- and micro-biology, genetics breeding methods and strategies, propagation, gene conservation, data analysis and statistics, each area with a comprehensive terminology. The terms selected...... for definition here are those most frequently used in tree improvement literature. Clonal propagation is included in the view of the great expansion of that field as a means of mass multiplication of improved material....

  11. Impacts of Flooding Regime Modification on Wildlife Habitats of Bottomland Hardwood Forests in the Lower Mississippi Valley.

    Science.gov (United States)

    1981-10-01

    styraciflua), shellbark hickory ( Carya laciniosa), and shagbark hickory (C. ovata) dominating in the control while American hornbeam and silver maple (Acer...Trees and Shrubs in the Lower Mississippi Valley (After Whitlow and Harris 1979) Common Name Scientific Name Very Tolerant* Water hickory Carya ...aquatica Pecan C. illinoensis Buttonbush Cephalanthus occidentalis Swamp privet Forestiera acuminata Green ash Fraxinus pennsylvanica Water locust Gleditsia

  12. 改性山核桃外果皮/竹刨花板制造工艺研究%Preparation Technology of Bamboo Particleboard Using Laccase Treated Exocarp of Cathay Hickory

    Institute of Scientific and Technical Information of China (English)

    王进; 张飞英; 韩素芳; 刘亚群

    2015-01-01

    Bamboo particleboards were prepared and the performances were measured with laccase treating exocarp of Cathay Hickory and adding modifi ed exocarp powder to reduce the glue content for bamboo particles bonding. The manufacturing technology was studied and the optimum parameters were: 10% of exocarp dosage, 60 U/g of laccase dosage, 6% of adhesive content, 1% of waterproof agent dosage, 27% of mat moisture content, 200℃ of hot pressing temperature, 3 MPa of pressing pressure, and 16 min of pressing time.%以漆酶改性处理的山核桃外果皮,代替部分胶黏剂添加到竹刨花中,研究山核桃外果皮粉用量、胶黏剂用量、漆酶用量、防水剂用量,板坯含水率、热压温度、热压压力、热压时间对山核桃外果皮/竹刨花板性能的影响;确定最优化的制板工艺参数:山核桃外果皮添加量10%、漆酶用量60 U/g、施胶量6%、防水剂用量1%,板坯含水率27%、热压温度200℃、热压压力3 MPa、热压时间为16 min。

  13. Methods for acquisition, storage, and evaluation of leguminous tree germplasm

    Energy Technology Data Exchange (ETDEWEB)

    Felker, P.

    1980-01-01

    Simple methods for establishing, maintaining, and planting of a small scale tree legume (Prosopis) germplasm collection by one or two people are described. Suggestions are included for: developing an understanding of the worldwide distribution of genus; becoming acquainted with basic and applied scientists working on the taxa; devising seed cleaning, fumigation, cataloging, and storage techniques; requesting seed from international seed collections; collecting seed from native populations; and for field designs for planting the germplasm collection.

  14. Moringa oleifera: Resource management and multiuse life tree

    OpenAIRE

    Santos, Andréa F. S.; Luz, Luciana A.; Pontual, Emmanuel V.; Napoleão, Thiago H.; Paiva, Patrícia M.G.; Coelho, Luana C. B. B.

    2015-01-01

    Moringa oleifera Lamarck (Moringaceae family) is a plant native from the Western and sub-Himalayan parts of Northwest India, Pakistan and Afghanistan. This species is widely cultivated across Africa, South-East Asia, Arabia, South America and Caribbean Islands. M. oleifera culture is also being distributed in the Semi-Arid Northeast of Brazil. It is a multiuse life tree with great environmental economic importance in industrial and medical areas. This review reports different purposes of M. o...

  15. Native Terrestrial Animal Species Richness

    Data.gov (United States)

    U.S. Environmental Protection Agency — These data represent predicted current distributions of all native mammals, birds, reptiles, amphibians and butterflies in the Middle-Atlantic region. The data are...

  16. Native grassland inventory and monitoring

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Benton Lake refuge has nearly 6,000 acres of native western wheatgrass-green needlegrass prairie uplands. This pilot study was designed to assess the condition of...

  17. Charting Transnational Native American Studies

    Directory of Open Access Journals (Sweden)

    Hsinya Huang

    2012-06-01

    Full Text Available Introduction to the Special Forum entitled "Charting Transnational Native American Studies: Aesthetics, Politics, Identity," edited by Hsinya Huang, Philip J. Deloria, Laura M. Furlan, and John Gamber

  18. Species of Mycosphaerellaceae and Teratosphaeriaceae on native Myrtaceae in Uruguay: evidence of fungal host jumps.

    Science.gov (United States)

    Pérez, C A; Wingfield, M J; Altier, N; Blanchette, R A

    2013-02-01

    Mycosphaerella species are well-known causal agents of leaf diseases on many economically and ecologically important plant species. In Uruguay, a relatively large number of Mycosphaerellaceae and Teratosphaeriaceae are found on Eucalyptus, but nothing is known of these fungi on native Myrtaceae. The aim of this study was to identify Mycosphaerellaceae and Teratosphaeriaceae species associated with leaf diseases on native Myrtaceae in Uruguay and to consider whether host jumps by the pathogen from introduced Eucalyptus to native Myrtaceae have occurred. Several native forests throughout the country were surveyed with special attention given to those located close to Eucalyptus plantations. Five species belonging to the Mycosphaerellaceae and Teratosphaeriaceae clades were found on native Myrtaceous trees and three of these had previously been reported on Eucalyptus in Uruguay. Those occurring both on Eucalyptus and native Myrtaceae included Pallidocercospora heimii, Pseudocercospora norchiensis, and Teratosphaeria aurantia. In addition, Mycosphaerella yunnanensis, a species known to occur on Eucalyptus but not previously recorded in Uruguay, was found on leaves of two native Myrtaceous hosts. Because most of these species occur on Eucalyptus in countries other than Uruguay, it appears that they were introduced in this country and have adapted to be able to infect native Myrtaceae. These apparent host jumps have the potential to result in serious disease problems and they should be carefully monitored.

  19. Geometric Decision Tree

    CERN Document Server

    Manwani, Naresh

    2010-01-01

    In this paper we present a new algorithm for learning oblique decision trees. Most of the current decision tree algorithms rely on impurity measures to assess the goodness of hyperplanes at each node while learning a decision tree in a top-down fashion. These impurity measures do not properly capture the geometric structures in the data. Motivated by this, our algorithm uses a strategy to assess the hyperplanes in such a way that the geometric structure in the data is taken into account. At each node of the decision tree, we find the clustering hyperplanes for both the classes and use their angle bisectors as the split rule at that node. We show through empirical studies that this idea leads to small decision trees and better performance. We also present some analysis to show that the angle bisectors of clustering hyperplanes that we use as the split rules at each node, are solutions of an interesting optimization problem and hence argue that this is a principled method of learning a decision tree.

  20. Tree felling 2014

    CERN Multimedia

    2014-01-01

    With a view to creating new landscapes and making its population of trees safer and healthier, this winter CERN will complete the tree-felling campaign started in 2010.   Tree felling will take place between 15 and 22 November on the Swiss part of the Meyrin site. This work is being carried out above all for safety reasons. The trees to be cut down are at risk of falling as they are too old and too tall to withstand the wind. In addition, the roots of poplar trees are very powerful and spread widely, potentially damaging underground networks, pavements and roadways. Compensatory tree planting campaigns will take place in the future, subject to the availability of funding, with the aim of creating coherent landscapes while also respecting the functional constraints of the site. These matters are being considered in close collaboration with the Geneva nature and countryside directorate (Direction générale de la nature et du paysage, DGNP). GS-SE Group

  1. Attack Trees with Sequential Conjunction

    NARCIS (Netherlands)

    Jhawar, Ravi; Kordy, Barbara; Mauw, Sjouke; Radomirović, Sasa; Trujillo-Rasua, Rolando

    2015-01-01

    We provide the first formal foundation of SAND attack trees which are a popular extension of the well-known attack trees. The SAND at- tack tree formalism increases the expressivity of attack trees by intro- ducing the sequential conjunctive operator SAND. This operator enables the modeling of

  2. Atmospheric dust accumulation on native and non-native species: effects on gas exchange parameters.

    Science.gov (United States)

    González, Juan A; Prado, Fernando E; Piacentini, Ruben D

    2014-05-01

    Plants are continuously exposed to atmospheric particulate matter (dust), and their leaves are the main receptors of deposited dust. The objective of this study was to assess the effects of dust deposition on leaf gas exchange parameters of 17 native and non-native tree and shrub species growing in Gran San Miguel de Tucumán in northwestern Argentina. Maximum assimilation rate (), stomatal conductance (), transpiration rate (), internal CO concentration (), and instantaneous water-use efficiency (WUE) were measured in cleaned leaves (CL) and dusted leaves (DL) of different species on November 2010, July 2011, and September 2011. In almost all studied species, gas exchange parameters were significantly affected by dust deposition. Values for , , and of DL were significantly reduced in 11, 12, and 14 species compared with CL. Morphological leaf traits seem to be related to reduction. Indeed, L. and (Mart. ex DC.) Standl. species with pubescent leaves and thick ribs showed the highest reduction percentages. Contrarily, and WUE were increased in DL but were less responsive to dust deposition than other parameters. Increases of and WUE were significant in 5 and 11 species, respectively. Correlation analyses between /, /, and / pairs showed significant positive linear correlations in CL and DL of many studied species, including small and tall plants. These results suggest that leaf stomatal factors and shade-induced effect by accumulated dust are primarily responsible for the observed reductions in photosynthesis rate of DL.

  3. On the neighbourhoods of trees

    CERN Document Server

    Humphries, Peter J

    2012-01-01

    Tree rearrangement operations typically induce a metric on the space of phylogenetic trees. One important property of these metrics is the size of the neighbourhood, that is, the number of trees exactly one operation from a given tree. We present an expression for the size of the TBR (tree bisection and reconnection) neighbourhood, thus answering a question first posed in [Annals of Combinatorics, 5, 2001 1-15].

  4. Gurjun-Oil Tree: Buddhist Way and the Conservation and Revitalization of Gurjun-Oil Trees in Isan Cultural Forests

    Directory of Open Access Journals (Sweden)

    Chatchawan Kaewsaen

    2010-01-01

    Full Text Available Problem statement: This research aimed at investigating the background of gurjun-oil trees in Iran cultural forests, the present situation and difficulties of gurjun-oil tress and the Buddhist way concerning the conservation and revitalization of them in Iran cultural forests. Approach: A qualitative research was applied to find the data in 7 forest areas of the province of Yasothon, Roi ET, Sisaket, Ubonratchathani, Burirum, Mahasarakham and Kakasin. The sample of 147 people was selected by means of a purposive sampling consisted of 42 key-informants, 70 people involved the conservation and revitalization of gurjun-oil trees and 35 general informants. The data were collected by survey, a participative observation, a non-participative observation, a structured in-depth interview, a non-structured in depth interview, a focus-group interview, a workshop and an evaluation of planting activity. Research data were analyzed according to research purposes and presented by means of a descriptive analysis. Results: The results revealed that gurjun-oil trees in Iran cultural forests (cultural forests in the north-east of Thailand were native trees which gave people a lot of useful thing; for example people used oil of gurjun-oil trees for tinder, torches and putty. The present situation is a sharp reduction in the number of trees, the forests deteriorated into denuded forests, the people degenerated into selfish persons and competed in using natural resources for living and commercial purposes. The Buddhist way concerning the conservation and revitalization of gurjun-oil trees was the participation of three sectors; they were community leaders, state leaders and monk leaders. Necessarily, all community members must do their right duties in order to conserve and revitalize gurjun-oil trees. Conclusion/Recommendations: In conclusion, the conservation and revitalization of Gurjun-oil trees must support by the participation of all social sectors then it will

  5. Production and analysis of recombinant tree nut allergens.

    Science.gov (United States)

    Willison, Leanna N; Sathe, Shridhar K; Roux, Kenneth H

    2014-03-01

    Allergic reactions to tree nuts are a growing global concern as the number of affected individuals continues to rise. Unlike some food allergies, tree nuts can cause severe reactions that persist throughout life. The tree nuts discussed in this review include those most commonly responsible for allergic reactions: cashew, almond, hazelnut, walnut, pecan, Brazil nut, pistachio, and chestnut. The native allergenic proteins derived from tree nuts are frequently difficult to isolate and purify and may not be adequately represented in aqueous nut protein extracts. Consequently, defined recombinant allergens have become useful reagents in a variety of immunoassays aimed at the diagnosis of tree nut allergy, assessing cross-reactivity between various nuts and other seeds, mapping of IgE binding epitopes, and analyzing the effects of the food matrix, food processing, and gastric digestion on allergenicity. This review describes the approaches that can be used for the production of recombinant tree nut allergens and addresses key issues associated with their production and downstream applications.

  6. Exotic weeds and fluctuating microclimate can constrain native plant regeneration in urban forest restoration.

    Science.gov (United States)

    Wallace, K J; Laughlin, Daniel C; Clarkson, Bruce D

    2017-02-09

    Restoring forest structure and composition is an important component of urban land management, but we lack clear understanding of the mechanisms driving restoration success. Here we studied two indicators of restoration success in temperate rainforests: native tree regeneration and epiphyte colonization. We hypothesized that ecosystem properties such as forest canopy openness, abundance of exotic herbaceous weeds, and the microclimate directly affect the density and diversity of native tree seedlings and epiphytes. Relationships between environmental conditions and the plant community were investigated in 27 restored urban forests spanning 3 to 70 years in age and in unrestored and remnant urban forests. We used structural equation modelling to determine the direct and indirect drivers of native tree regeneration and epiphyte colonization in the restored forests. Compared to remnant forest, unrestored forest had fewer native canopy tree species, significantly more light reaching the forest floor annually, and higher exotic weed cover. Additionally, epiphyte density was lower and native tree regeneration density was marginally lower in the unrestored forests. In restored forests, light availability was reduced to levels found in remnant forests within 20 years of restoration planting, followed shortly thereafter by declines in herbaceous exotic weeds and reduced fluctuation of relative humidity and soil temperatures. Contrary to expectations, canopy openness was only an indirect driver of tree regeneration and epiphyte colonization, but it directly regulated weed cover and microclimatic fluctuations, both of which directly drove the density and richness of regeneration and epiphyte colonization. Epiphyte density and diversity were also positively related to forest basal area, as large trees provide physical habitat for colonization. These results imply that ecosystem properties change predictably after initial restoration plantings, and that reaching critical

  7. Detection of Anaplasma sp. in Korean Native Goats (Capra aegagrus hircus) on Jeju Island, Korea.

    Science.gov (United States)

    Seong, Giyong; Han, Yu-Jung; Chae, Jeong-Byoung; Chae, Joon-Seok; Yu, Do-Hyeon; Lee, Young-Sung; Park, Jinho; Park, Bae-Keun; Yoo, Jae-Gyu; Choi, Kyoung-Seong

    2015-12-01

    Anaplasma species are obligate intracellular pathogens that can cause tick-borne diseases in mammalian hosts. To date, very few studies of their occurrence in Korean native goats (Capra aegagrus hircus) have been reported. In the present study, we investigated Anaplasma infection of Korean native goats on Jeju Island, Republic of Korea, and performed phylogenetic analysis based on the 16S rRNA gene sequences. Our results showed that Anaplasma infection was found mostly in adult female goats. The phylogenetic tree revealed that the 7 sequences identified in Korean native goats could belong to Anaplasma sp. and were distinct from A. marginale, A. centrale, and A. ovis. The results indicated that the sequences identified to belong to Anaplasma were closely related to sequences isolated from goats in China and were clustered within the same group. To our knowledge, this is the first study to detect Anaplasma sp. infection in Korean native goats.

  8. The inference of gene trees with species trees.

    Science.gov (United States)

    Szöllősi, Gergely J; Tannier, Eric; Daubin, Vincent; Boussau, Bastien

    2015-01-01

    This article reviews the various models that have been used to describe the relationships between gene trees and species trees. Molecular phylogeny has focused mainly on improving models for the reconstruction of gene trees based on sequence alignments. Yet, most phylogeneticists seek to reveal the history of species. Although the histories of genes and species are tightly linked, they are seldom identical, because genes duplicate, are lost or horizontally transferred, and because alleles can coexist in populations for periods that may span several speciation events. Building models describing the relationship between gene and species trees can thus improve the reconstruction of gene trees when a species tree is known, and vice versa. Several approaches have been proposed to solve the problem in one direction or the other, but in general neither gene trees nor species trees are known. Only a few studies have attempted to jointly infer gene trees and species trees. These models account for gene duplication and loss, transfer or incomplete lineage sorting. Some of them consider several types of events together, but none exists currently that considers the full repertoire of processes that generate gene trees along the species tree. Simulations as well as empirical studies on genomic data show that combining gene tree-species tree models with models of sequence evolution improves gene tree reconstruction. In turn, these better gene trees provide a more reliable basis for studying genome evolution or reconstructing ancestral chromosomes and ancestral gene sequences. We predict that gene tree-species tree methods that can deal with genomic data sets will be instrumental to advancing our understanding of genomic evolution.

  9. Steiner trees in industry

    CERN Document Server

    Du, Ding-Zhu

    2001-01-01

    This book is a collection of articles studying various Steiner tree prob­ lems with applications in industries, such as the design of electronic cir­ cuits, computer networking, telecommunication, and perfect phylogeny. The Steiner tree problem was initiated in the Euclidean plane. Given a set of points in the Euclidean plane, the shortest network interconnect­ ing the points in the set is called the Steiner minimum tree. The Steiner minimum tree may contain some vertices which are not the given points. Those vertices are called Steiner points while the given points are called terminals. The shortest network for three terminals was first studied by Fermat (1601-1665). Fermat proposed the problem of finding a point to minimize the total distance from it to three terminals in the Euclidean plane. The direct generalization is to find a point to minimize the total distance from it to n terminals, which is still called the Fermat problem today. The Steiner minimum tree problem is an indirect generalization. Sch...

  10. Odds-On Trees

    CERN Document Server

    Bose, Prosenjit; Douieb, Karim; Dujmovic, Vida; King, James; Morin, Pat

    2010-01-01

    Let R^d -> A be a query problem over R^d for which there exists a data structure S that can compute P(q) in O(log n) time for any query point q in R^d. Let D be a probability measure over R^d representing a distribution of queries. We describe a data structure called the odds-on tree, of size O(n^\\epsilon) that can be used as a filter that quickly computes P(q) for some query values q in R^d and relies on S for the remaining queries. With an odds-on tree, the expected query time for a point drawn according to D is O(H*+1), where H* is a lower-bound on the expected cost of any linear decision tree that solves P. Odds-on trees have a number of applications, including distribution-sensitive data structures for point location in 2-d, point-in-polytope testing in d dimensions, ray shooting in simple polygons, ray shooting in polytopes, nearest-neighbour queries in R^d, point-location in arrangements of hyperplanes in R^d, and many other geometric searching problems that can be solved in the linear-decision tree mo...

  11. Reinforcement Learning Trees.

    Science.gov (United States)

    Zhu, Ruoqing; Zeng, Donglin; Kosorok, Michael R

    In this paper, we introduce a new type of tree-based method, reinforcement learning trees (RLT), which exhibits significantly improved performance over traditional methods such as random forests (Breiman, 2001) under high-dimensional settings. The innovations are three-fold. First, the new method implements reinforcement learning at each selection of a splitting variable during the tree construction processes. By splitting on the variable that brings the greatest future improvement in later splits, rather than choosing the one with largest marginal effect from the immediate split, the constructed tree utilizes the available samples in a more efficient way. Moreover, such an approach enables linear combination cuts at little extra computational cost. Second, we propose a variable muting procedure that progressively eliminates noise variables during the construction of each individual tree. The muting procedure also takes advantage of reinforcement learning and prevents noise variables from being considered in the search for splitting rules, so that towards terminal nodes, where the sample size is small, the splitting rules are still constructed from only strong variables. Last, we investigate asymptotic properties of the proposed method under basic assumptions and discuss rationale in general settings.

  12. Covering R-trees

    CERN Document Server

    Berestovskii, V N

    2007-01-01

    We show that every inner metric space X is the metric quotient of a complete R-tree via a free isometric action, which we call the covering R-tree of X. The quotient mapping is a weak submetry (hence, open) and light. In the case of compact 1-dimensional geodesic space X, the free isometric action is via a subgroup of the fundamental group of X. In particular, the Sierpin'ski gasket and carpet, and the Menger sponge all have the same covering R-tree, which is complete and has at each point valency equal to the continuum. This latter R-tree is of particular interest because it is "universal" in at least two senses: First, every R-tree of valency at most the continuum can be isometrically embedded in it. Second, every Peano continuum is the image of it via an open light mapping. We provide a sketch of our previous construction of the uniform universal cover in the special case of inner metric spaces, the properties of which are used in the proof.

  13. [Hydraulic limitation on photosynthetic rate of old Populus simonii trees in sandy soil of north Shaanxi Province].

    Science.gov (United States)

    Zuo, Li-Xiang; Li, Yang-Yang; Chen, Jia-Cun

    2014-06-01

    'Old and dwarf trees' on the loess plateau region mainly occurred among mature trees rather than among small trees. To elucidate the mechanism of tree age on 'old and dwarf trees' formation, taking Populus simonii, a tree species that accounted for the largest portion of 'old and dwarf trees' on the loess plateau, as an example, the growth, photosynthesis and hydraulic traits of P. simonii trees with different ages (young: 13-15 years, mid-aged: 31-34 years, and old: 49-54 years) were measured. The results showed that the dieback length increased, and net photosynthetic rate, stomatal conductance, transpiration rate, and whole plant hydraulic conductance decreased significantly with the increasing tree age. Both net photosynthetic rate and stomatal conductance measured at different dates were significantly and positively related to the whole plant hydraulic conductance, suggesting that the decreasing photosynthetic rate of old trees was possibly caused by the declined hydraulic conductance. Although the resistance to cavitation in stems and leaves was stronger in old trees than in young and mid-aged trees, there were no differences in midday native stem embolization degree and leaf hydraulic conductance based on the vulnerability curve estimation, suggesting that the increased hydraulic resistance of the soil-root system is probably the most important reason for decreasing the whole plant hydraulic conductance of old trees.

  14. Visualization of Uncertain Contour Trees

    DEFF Research Database (Denmark)

    Kraus, Martin

    2010-01-01

    Contour trees can represent the topology of large volume data sets in a relatively compact, discrete data structure. However, the resulting trees often contain many thousands of nodes; thus, many graph drawing techniques fail to produce satisfactory results. Therefore, several visualization methods...... were proposed recently for the visualization of contour trees. Unfortunately, none of these techniques is able to handle uncertain contour trees although any uncertainty of the volume data inevitably results in partially uncertain contour trees. In this work, we visualize uncertain contour trees...... by combining the contour trees of two morphologically filtered versions of a volume data set, which represent the range of uncertainty. These two contour trees are combined and visualized within a single image such that a range of potential contour trees is represented by the resulting visualization. Thus...

  15. Effects of invasive alien kahili ginger (Hedychium gardnerianum) on native plant species regeneration in a Hawaiian rainforest

    Science.gov (United States)

    Minden, V.; Jacobi, J.D.; Porembski, S.; Boehmer, H.J.

    2010-01-01

    Questions: Does the invasive alien Hedychium gardnerianum (1) replace native understory species, (2) suppress natural regeneration of native plant species, (3) increase the invasiveness of other non-native plants and (4) are native forests are able to recover after removal of H. gardnerianum. Location: A mature rainforest in Hawai'i Volcanoes National Park on the island of Hawai'i (about 1200 m. a.s.l.; precipitation approximately 2770mm yr-1). Study sites included natural plots without effects of alien plants, ginger plots with a H. gardnerianum-domimted herb layer and cleared plots treated with herbicide to remove alien plants. Methods: Counting mature trees, saplings and seedlings of native and alien plant species. Using nonparametric H-tests to compare impact of H. gardnerianum on the structure of different sites. Results: Results confirmed the hypothesis that H. gardnerianum has negative effects on natural forest dynamics. Lower numbers of native tree seedlings and saplings were found on ginger-dominated plots. Furthermore, H. gardnerianum did not show negative effects on the invasive alien tree species Psidium cattleianum. Conclusions: This study reveals that where dominance of H. gardnerianum persists, regeneration of the forest by native species will be inhibited. Furthermore, these areas might experience invasion by P. cattleianum, resulting in displacement of native canopy species in the future, leading to a change in forest structure and loss of other species dependent on natural rainforest, such as endemic birds. However, if H. gardnerianum is removed the native Hawaiian forest is likely to regenerate and regain its natural structure. ?? 2009 International Association for Vegetation Science.

  16. Active flows on trees

    CERN Document Server

    Forrow, Aden; Dunkel, Jörn

    2016-01-01

    Coherent, large scale dynamics in many nonequilibrium physical, biological, or information transport networks are driven by small-scale local energy input. We introduce and explore a generic model for compressible active flows on tree networks. In contrast to thermally-driven systems, active friction selects discrete states with only a small number of oscillation modes activated at distinct fixed amplitudes. This state selection interacts with graph topology to produce different localized dynamical time scales in separate regions of large networks. Using perturbation theory, we systematically predict the stationary states of noisy networks and find good agreement with a Bayesian state estimation based on a hidden Markov model applied to simulated time series data on binary trees. While the number of stable states per tree scales exponentially with the number of edges, the mean number of activated modes in each state averages $\\sim 1/4$ the number of edges. More broadly, these results suggest that the macrosco...

  17. Generic Ising trees

    DEFF Research Database (Denmark)

    Durhuus, Bergfinnur Jøgvan; Napolitano, George Maria

    2012-01-01

    The Ising model on a class of infinite random trees is defined as a thermodynamiclimit of finite systems. A detailed description of the corresponding distribution of infinite spin configurations is given. As an application, we study the magnetization properties of such systems and prove that they......The Ising model on a class of infinite random trees is defined as a thermodynamiclimit of finite systems. A detailed description of the corresponding distribution of infinite spin configurations is given. As an application, we study the magnetization properties of such systems and prove...... that they exhibit no spontaneous magnetization. Furthermore, the values of the Hausdorff and spectral dimensions of the underlying trees are calculated and found to be, respectively,¯dh =2 and¯ds = 4/3....

  18. 78 FR 70956 - 30-Day Notice of Proposed Information Collection: Assessment of Native American, Alaska Native...

    Science.gov (United States)

    2013-11-27

    ... URBAN DEVELOPMENT 30-Day Notice of Proposed Information Collection: Assessment of Native American... Title of Information Collection: Assessment of Native American, Alaska Native and Native Hawaiian... American and Alaskan Native populations, most notably through the Indian Housing Block Grant. The level...

  19. Literacy Skill Differences between Adult Native English and Native Spanish Speakers

    Science.gov (United States)

    Herman, Julia; Cote, Nicole Gilbert; Reilly, Lenore; Binder, Katherine S.

    2013-01-01

    The goal of this study was to compare the literacy skills of adult native English and native Spanish ABE speakers. Participants were 169 native English speakers and 124 native Spanish speakers recruited from five prior research projects. The results showed that the native Spanish speakers were less skilled on morphology and passage comprehension…

  20. Literacy Skill Differences between Adult Native English and Native Spanish Speakers

    Science.gov (United States)

    Herman, Julia; Cote, Nicole Gilbert; Reilly, Lenore; Binder, Katherine S.

    2013-01-01

    The goal of this study was to compare the literacy skills of adult native English and native Spanish ABE speakers. Participants were 169 native English speakers and 124 native Spanish speakers recruited from five prior research projects. The results showed that the native Spanish speakers were less skilled on morphology and passage comprehension…

  1. Partial diagnosis of street tree under power lines in West Regional of Minas Gerais

    Directory of Open Access Journals (Sweden)

    Altamir Fernandes de Oliveira

    2016-03-01

    Full Text Available This work aimed to present a partial diagnosis of street tree under power grid in five cities in the West Region of Minas Gerais, which had more power outages because of conflicts with trees. We identified 186 trees, belonging to 17 species of exotic origin and 30 species of native origin. The most frequent species were Poincianella pluviosa (30.43%, Ligustrum lucidum (10.86%, Michelia champaca (6.52% and Schinus molle (4.89%, which together amounted to 52.7% of the assessed trees. Most trees (84.78% were located in streets wider than 7 m, and 36.55% of the trees were planted in sidewalks with a minimum of 2 m wide. Those trees present ther first bifurcation at over 1.80 m above ground level. The pruning performed due to conflicts with the grid amounted 40.22%. Trees with height equal or over 6 m represents 72.83% of the sampled population. It was observed that there is not an appropriate management plan of urban trees under the grid, as the trees frequency is concentrate on few species that were mostly medium and large size.

  2. The gene tree delusion.

    Science.gov (United States)

    Springer, Mark S; Gatesy, John

    2016-01-01

    Higher-level relationships among placental mammals are mostly resolved, but several polytomies remain contentious. Song et al. (2012) claimed to have resolved three of these using shortcut coalescence methods (MP-EST, STAR) and further concluded that these methods, which assume no within-locus recombination, are required to unravel deep-level phylogenetic problems that have stymied concatenation. Here, we reanalyze Song et al.'s (2012) data and leverage these re-analyses to explore key issues in systematics including the recombination ratchet, gene tree stoichiometry, the proportion of gene tree incongruence that results from deep coalescence versus other factors, and simulations that compare the performance of coalescence and concatenation methods in species tree estimation. Song et al. (2012) reported an average locus length of 3.1 kb for the 447 protein-coding genes in their phylogenomic dataset, but the true mean length of these loci (start codon to stop codon) is 139.6 kb. Empirical estimates of recombination breakpoints in primates, coupled with consideration of the recombination ratchet, suggest that individual coalescence genes (c-genes) approach ∼12 bp or less for Song et al.'s (2012) dataset, three to four orders of magnitude shorter than the c-genes reported by these authors. This result has general implications for the application of coalescence methods in species tree estimation. We contend that it is illogical to apply coalescence methods to complete protein-coding sequences. Such analyses amalgamate c-genes with different evolutionary histories (i.e., exons separated by >100,000 bp), distort true gene tree stoichiometry that is required for accurate species tree inference, and contradict the central rationale for applying coalescence methods to difficult phylogenetic problems. In addition, Song et al.'s (2012) dataset of 447 genes includes 21 loci with switched taxonomic names, eight duplicated loci, 26 loci with non-homologous sequences that are

  3. Adaptive Context Tree Weighting

    CERN Document Server

    O'Neill, Alexander; Shao, Wen; Sunehag, Peter

    2012-01-01

    We describe an adaptive context tree weighting (ACTW) algorithm, as an extension to the standard context tree weighting (CTW) algorithm. Unlike the standard CTW algorithm, which weights all observations equally regardless of the depth, ACTW gives increasing weight to more recent observations, aiming to improve performance in cases where the input sequence is from a non-stationary distribution. Data compression results show ACTW variants improving over CTW on merged files from standard compression benchmark tests while never being significantly worse on any individual file.

  4. Host use patterns by the European woodwasp, Sirex noctilio, in its native and invaded range.

    Directory of Open Access Journals (Sweden)

    Matthew P Ayres

    Full Text Available Accelerating introductions of forest insects challenge decision-makers who might or might not respond with surveillance programs, quarantines, eradication efforts, or biological control programs. Comparing ecological controls on indigenous vs. introduced populations could inform responses to new introductions. We studied the European woodwasp, Sirex noctilio, which is not a pest in its native forests, is a serious invasive pest in the southern hemisphere, and now has an uncertain future in North America after its introduction there. Indigenous populations of S. noctilio (in Galicia, Spain resembled those in New York in that S. noctilio were largely restricted to suppressed trees that were also dying for other reasons, and still only some dying trees showed evidence of S. noctilio: 20-40% and 35-51% in Galicia and New York, respectively. In both areas, P. sylvestris (native to Europe was the species most likely to have attacks in non-suppressed trees. P. resinosa, native to North America, does not appear dangerously susceptible to S. noctilio. P. radiata, which sustains high damage in the southern hemisphere, is apparently not innately susceptible because in Galicia it was less often used by native S. noctilio than either native pine (P. pinaster and P. sylvestris. Silvicultural practices in Galicia that maintain basal area at 25-40 m(2/ha limit S. noctilio abundance. More than 25 species of other xylophagous insects feed on pine in Galicia, but co-occurrences with S. noctilio were infrequent, so strong interspecific competition seemed unlikely. Evidently, S. noctilio in northeastern North America will be more similar to indigenous populations in Europe, where it is not a pest, than to introduced populations in the southern hemisphere, where it is. However, S. noctilio populations could behave differently when they reach forests of the southeastern U.S., where tree species, soils, climate, ecology, management, and landscape configurations of pine

  5. Error-tolerant Tree Matching

    CERN Document Server

    Oflazer, K

    1996-01-01

    This paper presents an efficient algorithm for retrieving from a database of trees, all trees that match a given query tree approximately, that is, within a certain error tolerance. It has natural language processing applications in searching for matches in example-based translation systems, and retrieval from lexical databases containing entries of complex feature structures. The algorithm has been implemented on SparcStations, and for large randomly generated synthetic tree databases (some having tens of thousands of trees) it can associatively search for trees with a small error, in a matter of tenths of a second to few seconds.

  6. Native birds and alien insects: spatial density dependence in songbird predation of invading oak gallwasps.

    Directory of Open Access Journals (Sweden)

    Karsten Schönrogge

    Full Text Available Revealing the interactions between alien species and native communities is central to understanding the ecological consequences of range expansion. Much has been learned through study of the communities developing around invading herbivorous insects. Much less, however, is known about the significance of such aliens for native vertebrate predators for which invaders may represent a novel food source. We quantified spatial patterns in native bird predation of invading gall-inducing Andricus wasps associated with introduced Turkey oak (Quercus cerris at eight sites across the UK. These gallwasps are available at high density before the emergence of caterpillars that are the principle spring food of native insectivorous birds. Native birds showed positive spatial density dependence in gall attack rates at two sites in southern England, foraging most extensively on trees with highest gall densities. In a subsequent study at one of these sites, positive spatial density dependence persisted through four of five sequential week-long periods of data collection. Both patterns imply that invading galls are a significant resource for at least some native bird populations. Density dependence was strongest in southern UK bird populations that have had longest exposure to the invading gallwasps. We hypothesise that this pattern results from the time taken for native bird populations to learn how to exploit this novel resource.

  7. New species of Mycosphaerella from Myrtaceae in plantations and native forests in eastern Australia.

    Science.gov (United States)

    Carnegie, Angus J; Burgess, Treena I; Beilharz, Vyrna; Wingfield, Michael J

    2007-01-01

    The majority of Mycosphaerella species from eucalypts (Eucalyptus, Corymbia and Angophora) in Australia have been recorded only from trees growing in plantations. This illustrates a bias in research in the past two decades toward commercial enterprise, and it emphasises a lack of understanding of the occurrence of these important fungi under natural conditions. Surveys of foliar fungi in native forests in eastern Australia, as well as adjacent plantations, thus have been initiated in recent years. In this study we describe four new species of Mycosphaerella from Eucalyptus spp. as well as other Myrtaceae. Mycosphaerella tumulosa sp. nov. (anamorph: Pseudocercospora sp.) was found on more than seven species of Eucalyptus and Corymbia in native forests and plantations in northeastern New South Wales and southeastern Queensland and appears to be relatively common, although not damaging to these trees. Mycosphaerella multiseptata sp. nov. was recorded from several locations on species of Angophora in native forests and amenity plantings. Mycosphaerella pseudovespa sp. nov. was found in one location in native forest on E. biturbinata. The first species of Mycosphaerella to be described from Syncarpia, M. syncarpiae sp. nov., was found in native forests in numerous locations from Sydney through to northeastern New South Wales and appears to be relatively common.

  8. A Suffix Tree Or Not a Suffix Tree?

    DEFF Research Database (Denmark)

    Starikovskaya, Tatiana; Vildhøj, Hjalte Wedel

    2015-01-01

    , in particular we do not require that S ends with a unique symbol. This corresponds to considering the more general definition of implicit or extended suffix trees. Such general suffix trees have many applications and are for example needed to allow efficient updates when suffix trees are built online. We prove...

  9. Tree Modeling with Real Tree-Parts Examples.

    Science.gov (United States)

    Xie, Ke; Yan, Feilong; Sharf, Andrei; Deussen, Oliver; Huang, Hui; Chen, Baoquan

    2016-12-01

    We introduce a 3D tree modeling technique that utilizes examples of real trees to enhance tree creation with realistic structures and fine-level details. In contrast to previous works that use smooth generalized cylinders to represent tree branches, our method generates realistic looking tree models with complex branching geometry by employing an exemplar database consisting of real-life trees reconstructed from scanned data. These trees are sliced into representative parts (denoted as tree-cuts), representing trunk logs and branching structures. In the modeling process, tree-cuts are positioned in space in an intuitive manner, serving as efficient proxies that guide the creation of the complete tree. Allometry rules are taken into account to ensure reasonable relations between adjacent branches. Realism is further enhanced by automatically transferring geometric textures from our database onto tree branches as well as by guided growing of foliage. Our results demonstrate the complexity and variety of trees that can be generated with our method within few minutes. We carry a user study to test the effectiveness of our modeling technique.

  10. Portraits of Tree Families

    NARCIS (Netherlands)

    Balgooy, van M.M.J.

    1998-01-01

    With the publication of the second volume of the series ‘Malesian Seed Plants’, entitled ‘Portraits of Tree Families’, I would like to refer to the Introduction of the first volume, ‘Spot-characters’ for a historical background and an explanation of the aims of this series. The present book treats 1

  11. Certified Kruskal's Tree Theorem

    Directory of Open Access Journals (Sweden)

    Christian Sternagel

    2014-07-01

    Full Text Available This article presents the first formalization of Kurskal's tree theorem in aproof assistant. The Isabelle/HOL development is along the lines of Nash-Williams' original minimal bad sequence argument for proving the treetheorem. Along the way, proofs of Dickson's lemma and Higman's lemma, as well as some technical details of the formalization are discussed.

  12. Cloning Ancient Trees

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    west of Tiananmen Square in Beijing, in Zhongshan Park, there stand several ancient cypress trees, each more than 1,000 years old. Their leafy crowns are all more than 20 meters high, while four have trunks that are 6 meters in circumference. The most unique of these

  13. The TS-Tree

    DEFF Research Database (Denmark)

    Assent, Ira; Krieger, Ralph; Afschari, Farzad;

    2008-01-01

    Continuous growth in sensor data and other temporal data increases the importance of retrieval and similarity search in time series data. Efficient time series query processing is crucial for interactive applications. Existing multidimensional indexes like the R-tree provide efficient querying fo...

  14. The TS-Tree

    DEFF Research Database (Denmark)

    Assent, Ira; Krieger, Ralph; Afschari, Farzad

    2008-01-01

    Continuous growth in sensor data and other temporal data increases the importance of retrieval and similarity search in time series data. Efficient time series query processing is crucial for interactive applications. Existing multidimensional indexes like the R-tree provide efficient querying fo...

  15. Accelerating dynamic genetic conservation efforts: Use of FT-IR spectroscopy for the rapid identification of trees resistant to destructive pathogens

    Science.gov (United States)

    C. Villari; R.A. Sniezko; L.E. Rodriguez-Saona; P. Bonello

    2017-01-01

    A strong focus on tree germplasm that can resist threats such as non-native insects and pathogens, or a changing climate, is fundamental for successful genetic conservation efforts. However, the unavailability of tools for rapid screening of tree germplasm for resistance to critical pathogens and insect pests is becoming an increasingly serious bottleneck. Here we...

  16. Effect of tree species and end seal on attractiveness and utility of cut bolts to the redbay Ambrosia beetle and granulate Ambrosia beetle (Coleoptera: Curculionidae: Scolytinae)

    Science.gov (United States)

    Albert E. Mayfield; James L. Hanula

    2012-01-01

    The redbay ambrosia beetle, Xyleborus glabratus Eichhoff, is a non-native invasive pest and vector of the fungus that causes laurel wilt disease in certain trees of the family Lauraceae. This study assessed the relative attractiveness and suitability of cut bolts of several tree species to X. glabratus. In 2009, female X. glabratus were equally attracted to traps...

  17. THE ALIEN STREET TREES OF FORTALEZA (NE BRAZIL: QUALITATIVE OBSERVATIONS AND THE INVENTORY OF TWO DISTRICTS

    Directory of Open Access Journals (Sweden)

    Marcelo Freire Moro

    2011-01-01

    Full Text Available Public tree planting is important for cities. It produces shadow, brings well-being for humans, and supports the urban fauna. But the cultivation of exotic plants can also be responsible for dissemination of invasive species. This paper aims to evaluate public tree planting in Fortaleza, Ceará state, in northeastern Brazil. From 2005 to 2009, qualitative observations on tree composition in the city were made. In 2006, a detailed inventory of all public trees was carried out in two districts of Fortaleza. Jointly, 2075 individuals grew here. Most of the tree species planted in Fortaleza are aliens, some are even invasive. The massive use of exotic plants in Fortaleza has negative consequences for the environmental education. People do not know the regional native trees, and thus are not concerned about the local biodiversity conservation. In spite of the huge amounts of native species available for ornamental purposes in the Brazilian flora, the street trees of Fortaleza are overwhelmingly aliens.

  18. Tree Transduction Tools for Cdec

    Directory of Open Access Journals (Sweden)

    Austin Matthews

    2014-09-01

    Full Text Available We describe a collection of open source tools for learning tree-to-string and tree-to-tree transducers and the extensions to the cdec decoder that enable translation with these. Our modular, easy-to-extend tools extract rules from trees or forests aligned to strings and trees subject to different structural constraints. A fast, multithreaded implementation of the Cohn and Blunsom (2009 model for extracting compact tree-to-string rules is also included. The implementation of the tree composition algorithm used by cdec is described, and translation quality and decoding time results are presented. Our experimental results add to the body of evidence suggesting that tree transducers are a compelling option for translation, particularly when decoding speed and translation model size are important.

  19. Tree Formation Using Coordinate Method

    Directory of Open Access Journals (Sweden)

    Monika Choudhary

    2015-06-01

    Full Text Available In this paper we are introducing a new method of tree formation, we propose a coordinate based method by which we can store and access tree structures. As we know in NLP, parsing is the most important module. The output of this module is generally parsed trees. Currently, TAG (Tree Adjoining Grammar is widely used grammar due to its linguistic and formal nature. It is simply tree generating system. The unit structure used in TAG is structured trees. So we used our new method to store trees where we worked on English to Hindi language. We worked on different sentences from English to Hindi, our method is the easiest way to manipulate tree. We have implemented within small corpus and for finite number of structures and further can be extended in future.

  20. Speech Recognition of Non-Native Speech Using Native and Non-Native Acoustic Models

    Science.gov (United States)

    2000-08-01

    NATIVE AND NON-NATIVE ACOUSTIC MODELS David A. van Leeuwen and Rosemary Orr vanLeeuwentm .tno. nl R. 0rr~kno. azn. nl TNO Human Factors Research...a] is pronounced closer to the [c] by the vowels . Journal of Phonetics, 25:437-470, 1997. 32 [2] D. B. Paul and J. M. Baker. The design for [9] R. H...J. Kershaw, [12] Tony Robinson. Private Communication. L. Lamel, D. A. van Leeuwen , D. Pye, A. J. Robinson, H. J. M. Steeneken, and P. C. Wood- [13

  1. Native herbaceous perennials as ornamentals

    DEFF Research Database (Denmark)

    Larsen, Bjarne; Ørgaard, Marian

    2013-01-01

    Gardening with native perennials is a way to bring nature closer to urban citizens and bring up reflections on nature in a busy world. During three seasons of trialing Salvia pratensis, Dianthus deltoides, Campanula trachelium, Vincetoxicum hirundinaria, Saxifraga granulata, Plantago media and P...

  2. Native American College Student Persistence

    Science.gov (United States)

    Mosholder, Richard; Goslin, Christopher

    2013-01-01

    Native American students are the most likely racial/ethnic group tracked in post-secondary American education to be affected by poverty and limited access to educational opportunities. In addition, they are the most likely to be required to take remedial course work and are the least likely to graduate from college. A review of the literature was…

  3. Native Art of the Southwest.

    Science.gov (United States)

    Langham, Barbara A.

    1997-01-01

    Provides historical information on native Southwest peoples and their arts to encourage appreciation and understanding of this cultural heritage. Provides instructions and supply lists for age-appropriate craft projects including woven baskets and rugs, clay pots, clay and paper beads, silver bracelets, kachina dolls, sand paintings, dream…

  4. The Tree of Industrial Life

    DEFF Research Database (Denmark)

    Andersen, Esben Sloth

    2002-01-01

    The purpose of this paper is to bring forth an interaction between evolutionary economics and industrial systematics. The suggested solution is to reconstruct the "family tree" of the industries. Such a tree is based on similarities, but it may also reflect the evolutionary history in industries...... finding of optimal industrial trees. The results are presented as taxonomic trees that can easily be compared with the hierarchical structure of existing systems of industrial classification....

  5. Native Grasses as a Management Alternative on Vegetated Closure Caps

    Science.gov (United States)

    Kwit, Charles; Collins, Beverly

    2008-06-01

    Capped waste sites often are vegetated with commercial turf grasses to increase evapotranspiration and prevent erosion and possible exposure of the barrier. Fertilizer, frequent watering, and mowing may be required to establish the turf grass and prevent invasion by trees and shrubs. Oldfield vegetation of grasses and forbs is a possible sustainable alternative to turf grass communities. To determine if oldfield vegetation can establish on caps, we (1) compared establishment of a dominant oldfield grass and a commercial turf grass under different combinations of new closure cap management: spring or summer planting and presence or absence of amendments to alleviate drought (watering, mulch) or increase soil fertility (fertilizer, lime, a nitrogen-fixing legume); (2) surveyed existing caps to determine if oldfield species establish naturally; and (3) performed a greenhouse experiment to compare growth of two native grasses under low and amended (added water, soil nutrients) conditions. Both the commercial grass and oldfield species established under new cap conditions; fertilizer, water, and mulch improved vegetation establishment in spring or summer, but legumes decreased grass cover. In the greenhouse, both native grasses grew best with amendments; however, substantial stem and root length were obtained with no fertilizer and only once-weekly watering. Existing vegetated caps supported planted grasses and naturally established oldfield species. Overall, the results indicate native grasses can establish on new caps and oldfields can serve as a management model; further work is needed to determine the management strategy to maintain herbaceous vegetation and slow woody species invasion.

  6. Observations on the fauna that visit African Tulip Tree (Spathodea campanulata Beauv.) forests in Puerto Rico

    Science.gov (United States)

    Oscar J. Abelleira Martinez

    2008-01-01

    Diurnal field observations in secondary forests dominated by the introduced African tulip tree (Spathodea campanulata) in Puerto Rico show a faunal assemblage that consists mostly of native species (81.1 percent). The most abundant species were common birds and reptiles, yet some uncommon fauna appear to be visiting or residing in these forests. The observations...

  7. 77 FR 72832 - Applications for New Awards; Native American and Alaska Native Children in School Program

    Science.gov (United States)

    2012-12-06

    ..., traditional languages spoken by Native Americans, consistent with section 103 of the Native American Languages... methods of evaluation will provide performance feedback and permit periodic assessment of progress...

  8. Protecting Trees Means Protecting Ourselves

    Institute of Scientific and Technical Information of China (English)

    刘国虹; 张超

    2016-01-01

    As everyone knows,spring is a planting season.Every year people all over China go out to plant trees.Trees can make our environment more beautifully~①.Trees can stop wind from blowing the earth and sand away.They can also prevent soil from being washed away by wa-

  9. Junction trees of general graphs

    Institute of Scientific and Technical Information of China (English)

    Xiaofei WANG; Jianhua GUO

    2008-01-01

    In this paper,we study the maximal prime subgraphs and their corresponding structure for any undirected graph.We introduce the notion of junction trees and investigate their structural characteristics,including junction properties,induced-subtree properties,running-intersection properties and maximum-weight spanning tree properties.Furthermore,the characters of leaves and edges on junction trees are discussed.

  10. Tree decompositions with small cost

    NARCIS (Netherlands)

    Bodlaender, H.L.; Fomin, F.V.

    2002-01-01

    The f-cost of a tree decomposition ({Xi | i e I}, T = (I;F)) for a function f : N -> R+ is defined as EieI f(|Xi|). This measure associates with the running time or memory use of some algorithms that use the tree decomposition. In this paper we investigate the problem to find tree decompositions

  11. Distance labeling schemes for trees

    DEFF Research Database (Denmark)

    Alstrup, Stephen; Gørtz, Inge Li; Bistrup Halvorsen, Esben;

    2016-01-01

    We consider distance labeling schemes for trees: given a tree with n nodes, label the nodes with binary strings such that, given the labels of any two nodes, one can determine, by looking only at the labels, the distance in the tree between the two nodes. A lower bound by Gavoille et al. [Gavoill...

  12. A Class of Graceful Trees

    Institute of Scientific and Technical Information of China (English)

    孟凡洪; 苏耕; 杨继

    2000-01-01

    The present paper shows the coordinates of a tree and its vertices, defines a kind of Trees with Odd-Number Radiant Type (TONRT), deals with the gracefulness of TONRT by using the edge-moving theorem, and uses graceful TONRT to construct another class of graceful trees.

  13. Generalising tree traversals to DAGs

    DEFF Research Database (Denmark)

    Bahr, Patrick; Axelsson, Emil

    2015-01-01

    We present a recursion scheme based on attribute grammars that can be transparently applied to trees and acyclic graphs. Our recursion scheme allows the programmer to implement a tree traversal and then apply it to compact graph representations of trees instead. The resulting graph traversals avoid...

  14. Spanning trees crossing few barriers

    NARCIS (Netherlands)

    Asano, T.; Berg, M. de; Cheong, O.; Guibas, L.J.; Snoeyink, J.; Tamaki, H.

    2002-01-01

    We consider the problem of finding low-cost spanning trees for sets of n points in the plane, where the cost of a spanning tree is defined as the total number of intersections of tree edges with a given set of m barriers. We obtain the following results: (i) if the barriers are possibly intersecting

  15. Selecting Landscape Plants: Flowering Trees

    OpenAIRE

    Relf, Diane; Appleton, Bonnie Lee, 1948-2012

    2009-01-01

    This publication helps the reader to select wisely among the many species and varieties of flowering trees available. The following are considerations that should be taken into account when choosing flowering trees for the home landscape: selections factors, environmental responses, availability and adaptability, and flowering tree descriptions.

  16. Rectilinear Full Steiner Tree Generation

    DEFF Research Database (Denmark)

    Zachariasen, Martin

    1999-01-01

    The fastest exact algorithm (in practice) for the rectilinear Steiner tree problem in the plane uses a two-phase scheme: First, a small but sufficient set of full Steiner trees (FSTs) is generated and then a Steiner minimum tree is constructed from this set by using simple backtrack search, dynamic...

  17. Generalising tree traversals to DAGs

    DEFF Research Database (Denmark)

    Bahr, Patrick; Axelsson, Emil

    2015-01-01

    We present a recursion scheme based on attribute grammars that can be transparently applied to trees and acyclic graphs. Our recursion scheme allows the programmer to implement a tree traversal and then apply it to compact graph representations of trees instead. The resulting graph traversals avoid...

  18. The Hopi Fruit Tree Book.

    Science.gov (United States)

    Nyhuis, Jane

    Referring as often as possible to traditional Hopi practices and to materials readily available on the reservation, the illustrated booklet provides information on the care and maintenance of young fruit trees. An introduction to fruit trees explains the special characteristics of new trees, e.g., grafting, planting pits, and watering. The…

  19. Native and Non-Native Perceptions on a Non-Native Oral Discourse in an Academic Setting

    Directory of Open Access Journals (Sweden)

    Kenan Dikilitaş

    2012-07-01

    Full Text Available This qualitative study investigates discourse-level patterns typically employed by a Turkish lecturer based on the syntactic patterns found in the collected data. More specifically, the study aims to reveal how different native and non-native speakers of English perceive discourse patterns used by a non-native lecturer teaching in English. The data gathered from a Turkish lecturer teaching finance, and the interviews both with the lecturer and the students. The lecturer and the students were videotaped and the data was evaluated by content analysis. The results revealed a difference between the way non-native and native speakers evaluate an oral discourse of a non-native lecturer teaching in English. Native speakers of English found the oral performance moderately comprehensible, while non-native speakers found it relatively comprehensible.

  20. A suffix tree or not a suffix tree?

    DEFF Research Database (Denmark)

    Starikovskaya, Tatiana; Vildhøj, Hjalte Wedel

    2015-01-01

    In this paper we study the structure of suffix trees. Given an unlabeled tree τ on n nodes and suffix links of its internal nodes, we ask the question “Is τ a suffix tree?”, i.e., is there a string S whose suffix tree has the same topological structure as τ? We place no restrictions on S, in part......In this paper we study the structure of suffix trees. Given an unlabeled tree τ on n nodes and suffix links of its internal nodes, we ask the question “Is τ a suffix tree?”, i.e., is there a string S whose suffix tree has the same topological structure as τ? We place no restrictions on S......, in particular we do not require that S ends with a unique symbol. This corresponds to considering the more general definition of implicit or extended suffix trees. Such general suffix trees have many applications and are for example needed to allow efficient updates when suffix trees are built online. Deciding...

  1. Evaluation of heritage trees for conservation and management in Guangzhou City (China).

    Science.gov (United States)

    Jim, C Y

    2004-01-01

    The recent fast pace of urbanization in China and other developing countries has exerted pressure on urban trees, which constitute a key urban environmental asset. The most outstanding trees should be treated as natural-cum-cultural heritage. Guangzhou City's growth has threatened its rich urban-tree endowment, a diversified assemblage of 200,000 trees represented by 254 species and located in three major habitats: roadside, park, and institutional grounds. Mainly based on age and performance, 348 trees were officially designated as heritage specimens. They were evaluated in the field for tree dimensions, habitat, performance, and landscape contribution, to establish enhanced conservation and management strategies. With only 25 species, heritage trees were dominated by five cultivated natives and encompass some of the city's rare species; some common urban-forest species were not represented. Older districts and roadside habitats, despite their compact town plan and limited growing space, had the largest tree dimensions and largest share of heritage trees. Many heritage trees were large with long life expectancy and the potential for biomass expansion, and had pivotal cityscape impacts where they occur. Old neighborhoods, traditional haven for the arborescent treasure, are being changed by construction activities and periodic typhoon and windstorm damages. Increasing development density could degrade the heritage trees and their growing space, and reduce tree quality and life span. Upgrading the statutory-administrative systems and arboricultural care can enhance long-term survival of the precious natural-cum-cultural heritage. The experience of Guangzhou in identifying and preserving its high-quality urban trees can provide management strategies for other cities.

  2. Fringe trees, Crump-Mode-Jagers branching processes and $m$-ary search trees

    OpenAIRE

    Holmgren, Cecilia; Janson, Svante

    2016-01-01

    This survey studies asymptotics of random fringe trees and extended fringe trees in random trees that can be constructed as family trees of a Crump-Mode-Jagers branching process, stopped at a suitable time. This includes random recursive trees, preferential attachment trees, fragmentation trees, binary search trees and (more generally) $m$-ary search trees, as well as some other classes of random trees. We begin with general results, mainly due to Aldous (1991) and Jagers and Nerman (1984). T...

  3. PoInTree: A Polar and Interactive Phylogenetic Tree

    Institute of Scientific and Technical Information of China (English)

    Carreras Marco; Gianti Eleonora; Sartori Luca; Plyte Simon Edward; Isacchi Antonella; Bosotti Roberta

    2005-01-01

    PoInTree (Polar and Innteractive Tree) is an application that allows to build, visualize, and customize phylogenetic trees in a polar, interactive, and highly flexible view. It takes as input a FASTA file or multiple alignment formats. Phylogenetic tree calculation is based on a sequence distance method and utilizes the Neighbor Joining (NJ) algorithm. It also allows displaying precalculated trees of the major protein families based on Pfam classification. In PoInTree, nodes can be dynamically opened and closed and distances between genes are graphically represented.Tree root can be centered on a selected leaf. Text search mechanism, color-coding and labeling display are integrated. The visualizer can be connected to an Oracle database containing information on sequences and other biological data, helping to guide their interpretation within a given protein family across multiple species.The application is written in Borland Delphi and based on VCL Teechart Pro 6 graphical component (Steema software).

  4. TREE SELECTING AND TREE RING MEASURING IN DENDROCHRONOLOGICAL INVESTIGATIONS

    Directory of Open Access Journals (Sweden)

    Sefa Akbulut

    2004-04-01

    Full Text Available Dendrochronology is a method of dating which makes use of the annual nature of tree growth. Dendrochronology may be divided into a number of subfields, each of which covers one or more aspects of the use of tree ring data: dendroclimatology, dendrogeomorphology, dendrohydrology, dendroecology, dendroarchaelogy, and dendrogylaciology. Basic of all form the analysis of the tree rings. The wood or tree rings can aid to dating past events about climatology, ecology, geology, hydrology. Dendrochronological studies are conducted either on increment cores or on discs. It may be seen abnormalities on tree rings during the measurement like that false rings, missing rings, reaction wood. Like that situation, increment cores must be extracted from four different sides of each tree and be studied as more as on tree.

  5. Is California bay laurel a suitable host for the non-native redbay ambrosia beetle, vector of laurel wilt disease?

    Science.gov (United States)

    Laurel wilt is a deadly vascular disease of trees in the Lauraceae that kills healthy redbay (Persea borbonia), sassafras (Sassafras albidum), and other related hosts. The fungal pathogen (Raffaelea lauricola) and it vector, the redbay ambrosia beetle (Xyleborus glabratus) are native to Asia and ha...

  6. Rate of tree carbon accumulation increases continuously with tree size.

    Science.gov (United States)

    Stephenson, N L; Das, A J; Condit, R; Russo, S E; Baker, P J; Beckman, N G; Coomes, D A; Lines, E R; Morris, W K; Rüger, N; Alvarez, E; Blundo, C; Bunyavejchewin, S; Chuyong, G; Davies, S J; Duque, A; Ewango, C N; Flores, O; Franklin, J F; Grau, H R; Hao, Z; Harmon, M E; Hubbell, S P; Kenfack, D; Lin, Y; Makana, J-R; Malizia, A; Malizia, L R; Pabst, R J; Pongpattananurak, N; Su, S-H; Sun, I-F; Tan, S; Thomas, D; van Mantgem, P J; Wang, X; Wiser, S K; Zavala, M A

    2014-03-06

    Forests are major components of the global carbon cycle, providing substantial feedback to atmospheric greenhouse gas concentrations. Our ability to understand and predict changes in the forest carbon cycle--particularly net primary productivity and carbon storage--increasingly relies on models that represent biological processes across several scales of biological organization, from tree leaves to forest stands. Yet, despite advances in our understanding of productivity at the scales of leaves and stands, no consensus exists about the nature of productivity at the scale of the individual tree, in part because we lack a broad empirical assessment of whether rates of absolute tree mass growth (and thus carbon accumulation) decrease, remain constant, or increase as trees increase in size and age. Here we present a global analysis of 403 tropical and temperate tree species, showing that for most species mass growth rate increases continuously with tree size. Thus, large, old trees do not act simply as senescent carbon reservoirs but actively fix large amounts of carbon compared to smaller trees; at the extreme, a single big tree can add the same amount of carbon to the forest within a year as is contained in an entire mid-sized tree. The apparent paradoxes of individual tree growth increasing with tree size despite declining leaf-level and stand-level productivity can be explained, respectively, by increases in a tree's total leaf area that outpace declines in productivity per unit of leaf area and, among other factors, age-related reductions in population density. Our results resolve conflicting assumptions about the nature of tree growth, inform efforts to undertand and model forest carbon dynamics, and have additional implications for theories of resource allocation and plant senescence.

  7. Genetic Diversity of mtDNA D-loop and Maternal Origin of Three Chinese Native Horse Breeds.

    Science.gov (United States)

    Zhang, Tao; Lu, Hongzhao; Chen, Chen; Jiang, Hai; Wu, Sanqiao

    2012-07-01

    In order to protect the genetic resource of native horse breeds, the genetic diversity of mitochondrial DNA (mtDNA) D-loop of three native horse breeds in western China were investigated. Forty-three 600 bp mtDNA D-loop sequences were analyzed by PCR and sequencing techniques, 33 unique haplotypes with 70 polymorphic sites were detected in these horses, which account for 11.67% of 600 bp sequence analyzed, showing the abundant genetic diversity of the three native horse breeds in western China. The Neighbour-Joining (NJ) phylogenetic tree based on 247 bp of 43 D-loop sequences demonstrated the presence of seven major lineages (A to G), indicating that the three native horse breeds in western China originated from multiple maternal origins. Consistent with the front, the NJ phylogenetic tree based on 600 bp of mtDNA D-loop sequences of 43 Chinese western native horses and 81 sequences of six horse breeds from GenBank indicated that the three horse breeds had distributed into the seven major lineages (A to G). The structure of the phylogenic tree is often blurred because the variation in a short segment of the mitochondrial genome is often accompanied by high levels of recurrent mutations. Consequently, longer D-loop sequences are helpful in achieving a higher level of molecular resolution in horses.

  8. Genetic Diversity of mtDNA D-loop and Maternal Origin of Three Chinese Native Horse Breeds

    Directory of Open Access Journals (Sweden)

    Tao Zhang

    2012-07-01

    Full Text Available In order to protect the genetic resource of native horse breeds, the genetic diversity of mitochondrial DNA (mtDNA D-loop of three native horse breeds in western China were investigated. Forty-three 600 bp mtDNA D-loop sequences were analyzed by PCR and sequencing techniques, 33 unique haplotypes with 70 polymorphic sites were detected in these horses, which account for 11.67% of 600 bp sequence analyzed, showing the abundant genetic diversity of the three native horse breeds in western China. The Neighbour-Joining (NJ phylogenetic tree based on 247 bp of 43 D-loop sequences demonstrated the presence of seven major lineages (A to G, indicating that the three native horse breeds in western China originated from multiple maternal origins. Consistent with the front, the NJ phylogenetic tree based on 600 bp of mtDNA D-loop sequences of 43 Chinese western native horses and 81 sequences of six horse breeds from GenBank indicated that the three horse breeds had distributed into the seven major lineages (A to G. The structure of the phylogenic tree is often blurred because the variation in a short segment of the mitochondrial genome is often accompanied by high levels of recurrent mutations. Consequently, longer D-loop sequences are helpful in achieving a higher level of molecular resolution in horses.

  9. Transport of Greenhouse Gases in Trees

    Science.gov (United States)

    Kutschera, E.; Khalil, A. K.; Shearer, M.; Rosenstiel, T.

    2009-12-01

    Emissions of greenhouse gases methane (CH4) and nitrous oxide (N2O) have been measured in cultivated and natural regions, quantifying overall emissions for croplands, wetlands, and forests. However, segregation between soil and plant emissions is less clear, and the dynamics behind each respective emission type differs. Better defined plant transport mechanisms will yield more accurate determination of greenhouse gas flux, contributing to a comprehensive theory quantifying greenhouse gas emissions globally. While the mechanisms of CH4 and N2O emissions from rice have not been fully identified, for trees these mechanisms are virtually unknown. CH4 and N2O emissions from several species of tree (Alnus rubra, Populus trichocarpa, Thuja plicata, Fraxinus latifolia) native to the Pacific Northwest have been measured. To identify mechanisms of gas transport, correlation of emissions and stomatal conductance, transpiration, and photosynthesis has been tested. A synthesis between plant physiological data and emissions is sought to elucidate the role plant physiology plays in the production and transport of CH4 and N2O. This research was supported by the Office of Science (BER), U. S. Department of Energy, Grant No. DE-FG02-08ER64515.

  10. Fault-Tree Compiler Program

    Science.gov (United States)

    Butler, Ricky W.; Martensen, Anna L.

    1992-01-01

    FTC, Fault-Tree Compiler program, is reliability-analysis software tool used to calculate probability of top event of fault tree. Five different types of gates allowed in fault tree: AND, OR, EXCLUSIVE OR, INVERT, and M OF N. High-level input language of FTC easy to understand and use. Program supports hierarchical fault-tree-definition feature simplifying process of description of tree and reduces execution time. Solution technique implemented in FORTRAN, and user interface in Pascal. Written to run on DEC VAX computer operating under VMS operating system.

  11. Native Americans Make Progress Against Diabetes Complication

    Science.gov (United States)

    ... fullstory_162979.html Native Americans Make Progress Against Diabetes Complication Kidney failure down by 54 percent over 2 ... Failure Recent Health News Related MedlinePlus Health Topics Diabetes Complications Kidney Failure Native American Health About MedlinePlus Site ...

  12. Native Communities and the Peruvian Constitutional Assembly

    Science.gov (United States)

    American Indian Journal, 1978

    1978-01-01

    A loosely knit coalition of over 25 native groups, the Peruvian Amazon Peoples has prepared a statement directed at the Peruvian Constitutional Assembly for purposes of Native input into the preparation of a revised national constitution. (JC)

  13. Global Value Trees

    Science.gov (United States)

    Zhu, Zhen; Puliga, Michelangelo; Cerina, Federica; Chessa, Alessandro; Riccaboni, Massimo

    2015-01-01

    The fragmentation of production across countries has become an important feature of the globalization in recent decades and is often conceptualized by the term “global value chains” (GVCs). When empirically investigating the GVCs, previous studies are mainly interested in knowing how global the GVCs are rather than how the GVCs look like. From a complex networks perspective, we use the World Input-Output Database (WIOD) to study the evolution of the global production system. We find that the industry-level GVCs are indeed not chain-like but are better characterized by the tree topology. Hence, we compute the global value trees (GVTs) for all the industries available in the WIOD. Moreover, we compute an industry importance measure based on the GVTs and compare it with other network centrality measures. Finally, we discuss some future applications of the GVTs. PMID:25978067

  14. Pushdown machines for the macro tree transducer

    NARCIS (Netherlands)

    Engelfriet, Joost; Vogler, Heiko

    1986-01-01

    The macro tree transducer can be considered as a system of recursive function procedures with parameters, where the recursion is on a tree (e.g., the syntax tree of a program). We investigate characterizations of the class of tree (tree-to-string) translations which is induced by macro tree transduc

  15. Tree Rings: Timekeepers of the Past.

    Science.gov (United States)

    Phipps, R. L.; McGowan, J.

    One of a series of general interest publications on science issues, this booklet describes the uses of tree rings in historical and biological recordkeeping. Separate sections cover the following topics: dating of tree rings, dating with tree rings, tree ring formation, tree ring identification, sample collections, tree ring cross dating, tree…

  16. Pushdown machines for the macro tree transducer

    NARCIS (Netherlands)

    Engelfriet, Joost; Vogler, Heiko

    1986-01-01

    The macro tree transducer can be considered as a system of recursive function procedures with parameters, where the recursion is on a tree (e.g., the syntax tree of a program). We investigate characterizations of the class of tree (tree-to-string) translations which is induced by macro tree

  17. Wood for the trees

    Directory of Open Access Journals (Sweden)

    Rob Garbutt

    2013-10-01

    Full Text Available Our paper focuses on the materiality, cultural history and cultural relations of selected artworks in the exhibition Wood for the trees (Lismore Regional Gallery, New South Wales, Australia, 10 June – 17 July 2011. The title of the exhibition, intentionally misreading the aphorism “Can’t see the wood for the trees”, by reading the wood for the resource rather than the collective wood[s], implies conservation, preservation, and the need for sustaining the originating resource. These ideas have particular resonance on the NSW far north coast, a region once rich in rainforest. While the Indigenous population had sustainable practices of forest and land management, the colonists deployed felling and harvesting in order to convert the value of the local, abundant rainforest trees into high-value timber. By the late twentieth century, however, a new wave of settlers launched a protest movements against the proposed logging of remnant rainforest at Terania Creek and elsewhere in the region. Wood for the trees, curated by Gallery Director Brett Adlington, plays on this dynamic relationship between wood, trees and people. We discuss the way selected artworks give expression to the themes or concepts of productive labour, nature and culture, conservation and sustainability, and memory. The artworks include Watjinbuy Marrawilil’s (1980 Carved ancestral figure ceremonial pole, Elizabeth Stops’ (2009/10 Explorations into colonisation, Hossein Valamanesh’s (2008 Memory stick, and AñA Wojak’s (2008 Unread book (in a forgotten language. Our art writing on the works, a practice informed by Bal (2002, Muecke (2008 and Papastergiadis (2004, becomes a conversation between the works and the themes or concepts. As a form of material excess of the most productive kind (Grosz, 2008, p. 7, art seeds a response to that which is in the air waiting to be said of the past, present and future.

  18. Source tree composition

    OpenAIRE

    Jonge, de, H.J.

    2002-01-01

    Dividing software systems in components improves software reusability as well as software maintainability. Components live at several levels, we concentrate on the implementation level where components are formed by source files, divided over directory structures. Such source code components are usually strongly coupled in the directory structure of a software system. Their compilation is usually controlled by a single global build process. This entangling of source trees and build processes ...

  19. Projecting invasion risk of non-native watersnakes (Nerodia fasciata and Nerodia sipedon) in the western United States.

    Science.gov (United States)

    Rose, Jonathan P; Todd, Brian D

    2014-01-01

    Species distribution models (SDMs) are increasingly used to project the potential distribution of introduced species outside their native range. Such studies rarely explicitly evaluate potential conflicts with native species should the range of introduced species expand. Two snake species native to eastern North America, Nerodia fasciata and Nerodia sipedon, have been introduced to California where they represent a new stressor to declining native amphibians, fish, and reptiles. To project the potential distributions of these non-native watersnakes in western North America, we built ensemble SDMs using MaxEnt, Boosted Regression Trees, and Random Forests and habitat and climatic variables. We then compared the overlap between the projected distribution of invasive watersnakes and the distributions of imperiled native amphibians, fish, and reptiles that can serve as prey or competitors for the invaders, to estimate the risk to native species posed by non-native watersnakes. Large areas of western North America were projected to be climatically suitable for both species of Nerodia according to our ensemble SDMs, including much of central California. The potential distributions of both N. fasciata and N. sipedon overlap extensively with the federally threatened Giant Gartersnake, Thamnophis gigas, which inhabits a similar ecological niche. N. fasciata also poses risk to the federally threatened California Tiger Salamander, Ambystoma californiense, whereas N. sipedon poses risk to some amphibians of conservation concern, including the Foothill Yellow-legged Frog, Rana boylii. We conclude that non-native watersnakes in California can likely inhabit ranges of several native species of conservation concern that are expected to suffer as prey or competing species for these invaders. Action should be taken now to eradicate or control these invasions before detrimental impacts on native species are widespread. Our methods can be applied broadly to quantify the risk posed by

  20. Projecting invasion risk of non-native watersnakes (Nerodia fasciata and Nerodia sipedon in the western United States.

    Directory of Open Access Journals (Sweden)

    Jonathan P Rose

    Full Text Available Species distribution models (SDMs are increasingly used to project the potential distribution of introduced species outside their native range. Such studies rarely explicitly evaluate potential conflicts with native species should the range of introduced species expand. Two snake species native to eastern North America, Nerodia fasciata and Nerodia sipedon, have been introduced to California where they represent a new stressor to declining native amphibians, fish, and reptiles. To project the potential distributions of these non-native watersnakes in western North America, we built ensemble SDMs using MaxEnt, Boosted Regression Trees, and Random Forests and habitat and climatic variables. We then compared the overlap between the projected distribution of invasive watersnakes and the distributions of imperiled native amphibians, fish, and reptiles that can serve as prey or competitors for the invaders, to estimate the risk to native species posed by non-native watersnakes. Large areas of western North America were projected to be climatically suitable for both species of Nerodia according to our ensemble SDMs, including much of central California. The potential distributions of both N. fasciata and N. sipedon overlap extensively with the federally threatened Giant Gartersnake, Thamnophis gigas, which inhabits a similar ecological niche. N. fasciata also poses risk to the federally threatened California Tiger Salamander, Ambystoma californiense, whereas N. sipedon poses risk to some amphibians of conservation concern, including the Foothill Yellow-legged Frog, Rana boylii. We conclude that non-native watersnakes in California can likely inhabit ranges of several native species of conservation concern that are expected to suffer as prey or competing species for these invaders. Action should be taken now to eradicate or control these invasions before detrimental impacts on native species are widespread. Our methods can be applied broadly to quantify

  1. Nest site characteristics of the Great-spotted Woodpecker in a bottomland riparian forest in the presence of invasive tree species

    Directory of Open Access Journals (Sweden)

    Ónodi Gábor

    2016-06-01

    Full Text Available This study was carried out in Hungary, in an old unmanaged riparian poplar-willow forest during the breeding seasons of 2014 and 2015. The occurrence of two invasive tree species, the green ash and boxelder, is significant in the study area, which influences negatively the populations of native riparian tree species in Central Europe. We studied Great-spotted Woodpecker nest sites in the presence of these invasive species. Throughout the study period, eight and twelve nesting cavity trees were mapped. Trees were recorded in 20-20 circular plots of 0.05 ha both for each mapped nest trees and random plots as well. Species, diameter at breast height and condition were recorded for each tree. Composition and diversity of nest site and random plots were compared. Distributions and preferences were calculated for nest tree use. Most of the recorded trees were invasive. Nest site plots had more native trees compared to random plots. Nest site showed higher diversity in terms of all three variables. Decayed and dead willow and white poplar hybrid trees were preferred for nesting. Diameter at breast height of nest trees was between 30-90 cm. Studies about cavity excavators in transformed habitats have high importance for nature conservation of riparian forests.

  2. Slim Sets of Binary Trees

    CERN Document Server

    Grünewald, Stefan

    2010-01-01

    A classical problem in phylogenetic tree analysis is to decide whether there is a phylogenetic tree $T$ that contains all information of a given collection $\\cP$ of phylogenetic trees. If the answer is "yes" we say that $\\cP$ is compatible and $T$ displays $\\cP$. This decision problem is NP-complete even if all input trees are quartets, that is binary trees with exactly four leaves. In this paper, we prove a sufficient condition for a set of binary phylogenetic trees to be compatible. That result is used to give a short and self-contained proof of the known characterization of quartet sets of minimal cardinality which are displayed by a unique phylogenetic tree.

  3. Making CSB + -Trees Processor Conscious

    DEFF Research Database (Denmark)

    Samuel, Michael; Pedersen, Anders Uhl; Bonnet, Philippe

    2005-01-01

    Cache-conscious indexes, such as CSB+-tree, are sensitive to the underlying processor architecture. In this paper, we focus on how to adapt the CSB+-tree so that it performs well on a range of different processor architectures. Previous work has focused on the impact of node size on the performance...... of the CSB+-tree. We argue that it is necessary to consider a larger group of parameters in order to adapt CSB+-tree to processor architectures as different as Pentium and Itanium. We identify this group of parameters and study how it impacts the performance of CSB+-tree on Itanium 2. Finally, we propose...... a systematic method for adapting CSB+-tree to new platforms. This work is a first step towards integrating CSB+-tree in MySQL’s heap storage manager....

  4. Active flows on trees

    Science.gov (United States)

    Forrow, Aden; Woodhouse, Francis G.; Dunkel, Jörn

    2016-11-01

    Coherent, large scale dynamics in many nonequilibrium physical, biological, or information transport networks are driven by small-scale local energy input. We introduce and explore a generic model for compressible active flows on tree networks. In contrast to thermally-driven systems, active friction selects discrete states with only a small number of oscillation modes activated at distinct fixed amplitudes. This state selection can interact with graph topology to produce different localized dynamical time scales in separate regions of large networks. Using perturbation theory, we systematically predict the stationary states of noisy networks. Our analytical predictions agree well with a Bayesian state estimation based on a hidden Markov model applied to simulated time series data on binary trees. While the number of stable states per tree scales exponentially with the number of edges, the mean number of activated modes in each state averages 1 / 4 the number of edges. More broadly, these results suggest that the macroscopic response of active networks, from actin-myosin networks in cells to flow networks in Physarum polycephalum, can be dominated by a few select modes.

  5. (Almost) practical tree codes

    KAUST Repository

    Khina, Anatoly

    2016-08-15

    We consider the problem of stabilizing an unstable plant driven by bounded noise over a digital noisy communication link, a scenario at the heart of networked control. To stabilize such a plant, one needs real-time encoding and decoding with an error probability profile that decays exponentially with the decoding delay. The works of Schulman and Sahai over the past two decades have developed the notions of tree codes and anytime capacity, and provided the theoretical framework for studying such problems. Nonetheless, there has been little practical progress in this area due to the absence of explicit constructions of tree codes with efficient encoding and decoding algorithms. Recently, linear time-invariant tree codes were proposed to achieve the desired result under maximum-likelihood decoding. In this work, we take one more step towards practicality, by showing that these codes can be efficiently decoded using sequential decoding algorithms, up to some loss in performance (and with some practical complexity caveats). We supplement our theoretical results with numerical simulations that demonstrate the effectiveness of the decoder in a control system setting.

  6. 34 CFR 300.29 - Native language.

    Science.gov (United States)

    2010-07-01

    ... 34 Education 2 2010-07-01 2010-07-01 false Native language. 300.29 Section 300.29 Education... DISABILITIES General Definitions Used in This Part § 300.29 Native language. (a) Native language, when used with respect to an individual who is limited English proficient, means the following: (1) The...

  7. Native American Children in Michigan. [Executive Summary

    Science.gov (United States)

    W. K. Kellogg Foundation, 2012

    2012-01-01

    "Native American Children in Michigan," provides a historical context for the tenuous relationship between Michigan's 12 federally recognized tribes and the state government, paying particular attention to the erosion of Native American education programs and the disproportionate number of Native children who find themselves in both the child…

  8. Gene tree correction for reconciliation and species tree inference

    Directory of Open Access Journals (Sweden)

    Swenson Krister M

    2012-11-01

    Full Text Available Abstract Background Reconciliation is the commonly used method for inferring the evolutionary scenario for a gene family. It consists in “embedding” inferred gene trees into a known species tree, revealing the evolution of the gene family by duplications and losses. When a species tree is not known, a natural algorithmic problem is to infer a species tree from a set of gene trees, such that the corresponding reconciliation minimizes the number of duplications and/or losses. The main drawback of reconciliation is that the inferred evolutionary scenario is strongly dependent on the considered gene trees, as few misplaced leaves may lead to a completely different history, with significantly more duplications and losses. Results In this paper, we take advantage of certain gene trees’ properties in order to preprocess them for reconciliation or species tree inference. We flag certain duplication vertices of a gene tree, the “non-apparent duplication” (NAD vertices, as resulting from the misplacement of leaves. In the case of species tree inference, we develop a polynomial-time heuristic for removing the minimum number of species leading to a set of gene trees that exhibit no NAD vertices with respect to at least one species tree. In the case of reconciliation, we consider the optimization problem of removing the minimum number of leaves or species leading to a tree without any NAD vertex. We develop a polynomial-time algorithm that is exact for two special classes of gene trees, and show a good performance on simulated data sets in the general case.

  9. Rate of tree carbon accumulation increases continuously with tree size

    Science.gov (United States)

    Stephenson, N.L.; Das, A.J.; Condit, R.; Russo, S.E.; Baker, P.J.; Beckman, N.G.; Coomes, D.A.; Lines, E.R.; Morris, W.K.; Rüger, N.; Álvarez, E.; Blundo, C.; Bunyavejchewin, S.; Chuyong, G.; Davies, S.J.; Duque, Á.; Ewango, C.N.; Flores, O.; Franklin, J.F.; Grau, H.R.; Hao, Z.; Harmon, M.E.; Hubbell, S.P.; Kenfack, D.; Lin, Y.; Makana, J.-R.; Malizia, A.; Malizia, L.R.; Pabst, R.J.; Pongpattananurak, N.; Su, S.-H.; Sun, I-F.; Tan, S.; Thomas, D.; van Mantgem, P.J.; Wang, X.; Wiser, S.K.; Zavala, M.A.

    2014-01-01

    Forests are major components of the global carbon cycle, providing substantial feedback to atmospheric greenhouse gas concentrations. Our ability to understand and predict changes in the forest carbon cycle—particularly net primary productivity and carbon storage - increasingly relies on models that represent biological processes across several scales of biological organization, from tree leaves to forest stands. Yet, despite advances in our understanding of productivity at the scales of leaves and stands, no consensus exists about the nature of productivity at the scale of the individual tree, in part because we lack a broad empirical assessment of whether rates of absolute tree mass growth (and thus carbon accumulation) decrease, remain constant, or increase as trees increase in size and age. Here we present a global analysis of 403 tropical and temperate tree species, showing that for most species mass growth rate increases continuously with tree size. Thus, large, old trees do not act simply as senescent carbon reservoirs but actively fix large amounts of carbon compared to smaller trees; at the extreme, a single big tree can add the same amount of carbon to the forest within a year as is contained in an entire mid-sized tree. The apparent paradoxes of individual tree growth increasing with tree size despite declining leaf-level and stand-level productivity can be explained, respectively, by increases in a tree’s total leaf area that outpace declines in productivity per unit of leaf area and, among other factors, age-related reductions in population density. Our results resolve conflicting assumptions about the nature of tree growth, inform efforts to understand and model forest carbon dynamics, and have additional implications for theories of resource allocation and plant senescence.

  10. Native herbaceous perennials as ornamentals

    DEFF Research Database (Denmark)

    Larsen, Bjarne; Ørgaard, Marian

    2013-01-01

    Gardening with native perennials is a way to bring nature closer to urban citizens and bring up reflections on nature in a busy world. During three seasons of trialing Salvia pratensis, Dianthus deltoides, Campanula trachelium, Vincetoxicum hirundinaria, Saxifraga granulata, Plantago media and P....... as a realistic plant community with an attractive, low habit and beautiful colors. Phyteuma spicatum is an attractive, novel species for a shady garden site.......Gardening with native perennials is a way to bring nature closer to urban citizens and bring up reflections on nature in a busy world. During three seasons of trialing Salvia pratensis, Dianthus deltoides, Campanula trachelium, Vincetoxicum hirundinaria, Saxifraga granulata, Plantago media and P....... maritima were found suitable for cultivation in wholesale-containers and applicable for dry, sunny conditions in gardens. On the other hand, Narthecium ossifragum, Pulsatilla palustris, Drosera rotundifolia, Vaccinium oxycoccos, Eriophorum angustifolium and Sphagnum sp. were cultivated and planted...

  11. Native Speakers in Linguistic Imperialism

    DEFF Research Database (Denmark)

    Phillipson, Robert

    2016-01-01

    An investigation of Native English Speaking Teachers’ performance in schemes in six Asian contexts, commissioned by the British Council, and undertaken by three British academics, is subjected to critical evaluation. Key issues for exploration are the issue of a monolingual approach to English...... learning and teaching, and the inappropriate qualifications of those sent to education systems when they are unfamiliar with the learners’ languages, cultures, and pedagogical traditions. Whether the schemes involved constitute linguistic imperialismis analysed. Whereas the need for multilingual competence...... is recognised as desirable by some British experts, the native speakers in question seldom have this key qualification. This is even the case when the host country (Brunei) aims at bilingual education. It is unlikely that the host countries are getting value for money. Whether the UK and other ‘English...

  12. Comparison of noble fir progeny from US Pacific Northwest collection regions and Denmark for Christmas tree traits

    DEFF Research Database (Denmark)

    Landgren, Chal; Nielsen, Ulrik Braüner; Chastagner, Gary

    2017-01-01

    positively correlated while colour showed little correlation with either trait. Provenances from the Oregon Coast and Willapa Hills, Washington provided the highest potential gain for Christmas tree market value. Provenances from Denmark exhibited superior colour and slow growth. For breeding purposes......Noble fir is the leading Christmas tree produced in the US Pacific Northwest (PNW). This study is based on evaluations of 24,721 trees collected from five native collection regions in Oregon and Washington plus imported seed from Denmark. The major collection areas were further subdivided...... into provenances utilizing 16 in the PNW and 6 from Denmark. A total of 22 test sites were evaluated from progeny trials planted between 1996 and 2007. Traits important for commercial Christmas tree production were evaluated and include commercial height, tree grade, value and colour. Tree height and quality were...

  13. Ecological impacts of non-native species

    Science.gov (United States)

    Wilkinson, John W.

    2012-01-01

    Non-native species are considered one of the greatest threats to freshwater biodiversity worldwide (Drake et al. 1989; Allen and Flecker 1993; Dudgeon et al. 2005). Some of the first hypotheses proposed to explain global patterns of amphibian declines included the effects of non-native species (Barinaga 1990; Blaustein and Wake 1990; Wake and Morowitz 1991). Evidence for the impact of non-native species on amphibians stems (1) from correlative research that relates the distribution or abundance of a species to that of a putative non-native species, and (2) from experimental tests of the effects of a non-native species on survival, growth, development or behaviour of a target species (Kats and Ferrer 2003). Over the past two decades, research on the effects of non-native species on amphibians has mostly focused on introduced aquatic predators, particularly fish. Recent research has shifted to more complex ecological relationships such as influences of sub-lethal stressors (e.g. contaminants) on the effects of non-native species (Linder et al. 2003; Sih et al. 2004), non-native species as vectors of disease (Daszak et al. 2004; Garner et al. 2006), hybridization between non-natives and native congeners (Riley et al. 2003; Storfer et al. 2004), and the alteration of food-webs by non-native species (Nystrom et al. 2001). Other research has examined the interaction of non-native species in terms of facilitation (i.e. one non-native enabling another to become established or spread) or the synergistic effects of multiple non-native species on native amphibians, the so-called invasional meltdown hypothesis (Simerloff and Von Holle 1999). Although there is evidence that some non-native species may interact (Ricciardi 2001), there has yet to be convincing evidence that such interactions have led to an accelerated increase in the number of non-native species and cumulative impacts are still uncertain (Simberloff 2006). Applied research on the control, eradication, and

  14. Native Terrestrial Animal Species Richness

    Science.gov (United States)

    These data represent predicted current distributions of all native mammals, birds, reptiles, amphibians and butterflies in the Middle-Atlantic region. The data are available for both 8-digit HUCs and EMAP hexagons and represent total species counts for each spatial unit. More information about these resources, including the variables used in this study, may be found here: https://edg.epa.gov/data/Public/ORD/NERL/ReVA/ReVA_Data.zip.

  15. Determinants of success in native and non-native listening comprehension: an individual differences approach

    NARCIS (Netherlands)

    S. Andringa; N. Olsthoorn; C. van Beuningen; R. Schoonen; J. Hulstijn

    2012-01-01

    The goal of this study was to explain individual differences in both native and non-native listening comprehension; 121 native and 113 non-native speakers of Dutch were tested on various linguistic and nonlinguistic cognitive skills thought to underlie listening comprehension. Structural equation mo

  16. Delayed Next Turn Repair Initiation in Native/Non-native Speaker English Conversation.

    Science.gov (United States)

    Wong, Jean

    2000-01-01

    Examines a form of other-initiated conversational repair that is delayed within next turn position, a form that is produced by non-native speakers of English whose native language is Mandarin. Using the framework of conversational analysis, shows that in native/non-native conversation, other-initiated repair is not always done as early as possible…

  17. Impact of an Alien Invasive Shrub on Ecology of Native and Alien Invasive Mosquito Species (Diptera: Culicidae).

    Science.gov (United States)

    Muturi, Ephantus J; Gardner, Allison M; Bara, Jeffrey J

    2015-10-01

    We examined how leaf litter of alien invasive honeysuckle (Lonicera maackii Rupr.) either alone or in combination with leaf litter of one of two native tree species, sugar maple (Acer saccharum Marshall) and northern red oak (Quercus rubra L.), affects the ecology of Culex restuans Theobald, Ochlerotatus triseriatus Say, and Ochlerotatus japonicus Theobald. Experimental mesocosms containing single species litter or a mixture of honeysuckle and one of two native tree species litter were established at South Farms and Trelease Woods study sites in Urbana, IL, and examined for their effect on 1) oviposition site selection by the three mosquito species, and 2) adult production and body size of Oc. triseriatus and Oc. japonicus. There were no significant effects of study site and leaf treatment on Oc. japonicus and Oc. triseriatus oviposition preference and adult production. In contrast, significantly more Cx. restuans eggs rafts were collected at South Farms relative to Trelease Woods and in honeysuckle litter relative to native tree species litter. Significantly larger adult females of Oc. japonicus and Oc. triseriatus were collected at South Farms relative to Trelease Woods and in honeysuckle litter relative to native tree species litter. Combining honeysuckle litter with native tree species litter had additive effects on Cx. restuans oviposition preference and Oc. japonicus and Oc. triseriatus body size, with the exception of honeysuckle and northern red oak litter combination, which had antagonistic effects on Oc. triseriatus body size. We conclude that input of honeysuckle litter into container aquatic habitats may alter the life history traits of vector mosquito species. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  18. 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

  19. 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

  20. Free classification of American English dialects by native and non-native listeners.

    Science.gov (United States)

    Clopper, Cynthia G; Bradlow, Ann R

    2009-10-01

    Most second language acquisition research focuses on linguistic structures, and less research has examined the acquisition of sociolinguistic patterns. The current study explored the perceptual classification of regional dialects of American English by native and non-native listeners using a free classification task. Results revealed similar classification strategies for the native and non-native listeners. However, the native listeners were more accurate overall than the non-native listeners. In addition, the non-native listeners were less able to make use of constellations of cues to accurately classify the talkers by dialect. However, the non-native listeners were able to attend to cues that were either phonologically or sociolinguistically relevant in their native language. These results suggest that non-native listeners can use information in the speech signal to classify talkers by regional dialect, but that their lack of signal-independent cultural knowledge about variation in the second language leads to less accurate classification performance.

  1. Interactions between carbon sequestration and shade tree diversity in a smallholder coffee cooperative in El Salvador.

    Science.gov (United States)

    Richards, Meryl Breton; Méndez, V Ernesto

    2014-04-01

    Agroforestry systems have substantial potential to conserve native biodiversity and provide ecosystem services. In particular, agroforestry systems have the potential to conserve native tree diversity and sequester carbon for climate change mitigation. However, little research has been conducted on the temporal stability of species diversity and aboveground carbon stocks in these systems or the relation between species diversity and aboveground carbon sequestration. We measured changes in shade-tree diversity and shade-tree carbon stocks in 14 plots of a 35-ha coffee cooperative over 9 years and analyzed relations between species diversity and carbon sequestration. Carbon sequestration was positively correlated with initial species richness of shade trees. Species diversity of shade trees did not change significantly over the study period, but carbon stocks increased due to tree growth. Our results show a potential for carbon sequestration and long-term biodiversity conservation in smallholder coffee agroforestry systems and illustrate the opportunity for synergies between biodiversity conservation and climate change mitigation. © 2013 Society for Conservation Biology.

  2. Invasive Acer negundo outperforms native species in non-limiting resource environments due to its higher phenotypic plasticity

    Directory of Open Access Journals (Sweden)

    Porté Annabel J

    2011-11-01

    Full Text Available Abstract Background To identify the determinants of invasiveness, comparisons of traits of invasive and native species are commonly performed. Invasiveness is generally linked to higher values of reproductive, physiological and growth-related traits of the invasives relative to the natives in the introduced range. Phenotypic plasticity of these traits has also been cited to increase the success of invasive species but has been little studied in invasive tree species. In a greenhouse experiment, we compared ecophysiological traits between an invasive species to Europe, Acer negundo, and early- and late-successional co-occurring native species, under different light, nutrient availability and disturbance regimes. We also compared species of the same species groups in situ, in riparian forests. Results Under non-limiting resources, A. negundo seedlings showed higher growth rates than the native species. However, A. negundo displayed equivalent or lower photosynthetic capacities and nitrogen content per unit leaf area compared to the native species; these findings were observed both on the seedlings in the greenhouse experiment and on adult trees in situ. These physiological traits were mostly conservative along the different light, nutrient and disturbance environments. Overall, under non-limiting light and nutrient conditions, specific leaf area and total leaf area of A. negundo were substantially larger. The invasive species presented a higher plasticity in allocation to foliage and therefore in growth with increasing nutrient and light availability relative to the native species. Conclusions The higher level of plasticity of the invasive species in foliage allocation in response to light and nutrient availability induced a better growth in non-limiting resource environments. These results give us more elements on the invasiveness of A. negundo and suggest that such behaviour could explain the ability of A. negundo to outperform native tree

  3. Invasive Acer negundo outperforms native species in non-limiting resource environments due to its higher phenotypic plasticity.

    Science.gov (United States)

    Porté, Annabel J; Lamarque, Laurent J; Lortie, Christopher J; Michalet, Richard; Delzon, Sylvain

    2011-11-24

    To identify the determinants of invasiveness, comparisons of traits of invasive and native species are commonly performed. Invasiveness is generally linked to higher values of reproductive, physiological and growth-related traits of the invasives relative to the natives in the introduced range. Phenotypic plasticity of these traits has also been cited to increase the success of invasive species but has been little studied in invasive tree species. In a greenhouse experiment, we compared ecophysiological traits between an invasive species to Europe, Acer negundo, and early- and late-successional co-occurring native species, under different light, nutrient availability and disturbance regimes. We also compared species of the same species groups in situ, in riparian forests. Under non-limiting resources, A. negundo seedlings showed higher growth rates than the native species. However, A. negundo displayed equivalent or lower photosynthetic capacities and nitrogen content per unit leaf area compared to the native species; these findings were observed both on the seedlings in the greenhouse experiment and on adult trees in situ. These physiological traits were mostly conservative along the different light, nutrient and disturbance environments. Overall, under non-limiting light and nutrient conditions, specific leaf area and total leaf area of A. negundo were substantially larger. The invasive species presented a higher plasticity in allocation to foliage and therefore in growth with increasing nutrient and light availability relative to the native species. The higher level of plasticity of the invasive species in foliage allocation in response to light and nutrient availability induced a better growth in non-limiting resource environments. These results give us more elements on the invasiveness of A. negundo and suggest that such behaviour could explain the ability of A. negundo to outperform native tree species, contributes to its spread in European resource

  4. Carbon storage landscapes of lowland Hawaii: the role of native and invasive species through space and time.

    Science.gov (United States)

    Hughes, R Flint; Asner, Gregory P; Mascaro, Joseph; Uowolo, Amanda; Baldwin, James

    2014-06-01

    Tropical forests are important storehouses of carbon and biodiversity. In isolated island ecosystems such as the Hawaiian Islands, relative dominance of native and nonnative tree species may influence patterns of forest carbon stocks and biodiversity. We determined aboveground carbon density (ACD) across a matrix of lava flows differing in age, texture, and vegetation composition (i.e., native or nonnative dominated) in wet lowland forests of Hawaii Island. To do this at the large scales necessary to accurately capture the inherent heterogeneity of these forests, we collected LiDAR data across areas of interest and developed relationships between LiDAR metrics and field-based estimates of forest ACD. This approach enabled us to inventory, rather than merely sample, the entire populations (i.e., forests) of interest. Native Hawaiian wet lowland forests exhibited ACD values similar to those of intact tropical forests elsewhere. In general, ACD of these forests increased with increasing lava flow age, but patterns differed between native and nonnative forest stands. On the youngest lavas, native-dominated forest ACD averaged < 60 Mg/ha, compared to -100 Mg C/ha for nonnative-dominated forests. This difference was due to the presence of the nonnative, N2-fixing trees F. moluccana and C. equisetifolia in the nonnative-dominated forest stands, as well as the corresponding absence of N2-fixing trees in native-dominated forest stands. Following -500 years of primary succession and thereafter, however, both forest types exhibited ACD values averaging -130 Mg C/ha, although it took nonnative forests only 75 80 years of post-establishment succession to reach those values. Given the large areas of early-successional M. polymorpha-dominated forest on young lava flows, further spread of F. moluccana and C. equisetifolia populations would likely increase ACD stocks but would constitute a significant erosion of the invaluable contribution of Hawaii's native ecosystems to global

  5. Invasive Acer negundo outperforms native species in non-limiting resource environments due to its higher phenotypic plasticity

    Science.gov (United States)

    2011-01-01

    Background To identify the determinants of invasiveness, comparisons of traits of invasive and native species are commonly performed. Invasiveness is generally linked to higher values of reproductive, physiological and growth-related traits of the invasives relative to the natives in the introduced range. Phenotypic plasticity of these traits has also been cited to increase the success of invasive species but has been little studied in invasive tree species. In a greenhouse experiment, we compared ecophysiological traits between an invasive species to Europe, Acer negundo, and early- and late-successional co-occurring native species, under different light, nutrient availability and disturbance regimes. We also compared species of the same species groups in situ, in riparian forests. Results Under non-limiting resources, A. negundo seedlings showed higher growth rates than the native species. However, A. negundo displayed equivalent or lower photosynthetic capacities and nitrogen content per unit leaf area compared to the native species; these findings were observed both on the seedlings in the greenhouse experiment and on adult trees in situ. These physiological traits were mostly conservative along the different light, nutrient and disturbance environments. Overall, under non-limiting light and nutrient conditions, specific leaf area and total leaf area of A. negundo were substantially larger. The invasive species presented a higher plasticity in allocation to foliage and therefore in growth with increasing nutrient and light availability relative to the native species. Conclusions The higher level of plasticity of the invasive species in foliage allocation in response to light and nutrient availability induced a better growth in non-limiting resource environments. These results give us more elements on the invasiveness of A. negundo and suggest that such behaviour could explain the ability of A. negundo to outperform native tree species, contributes to its spread

  6. Ectomycorrhizal fungi associated with ponderosa pine and Douglas-fir: a comparison of species richness in native western North American forests and Patagonian plantations from Argentina.

    Science.gov (United States)

    Barroetaveña, C; Cázares, E; Rajchenberg, M

    2007-07-01

    The putative ectomycorrhizal fungal species registered from sporocarps associated with ponderosa pine and Douglas-fir forests in their natural range distribution (i.e., western Canada, USA, and Mexico) and from plantations in south Argentina and other parts of the world are listed. One hundred and fifty seven taxa are reported for native ponderosa pine forests and 514 taxa for native Douglas-fir forests based on available literature and databases. A small group of genera comprises a high proportion of the species richness for native Douglas-fir (i.e., Cortinarius, Inocybe, and Russula), whereas in native ponderosa pine, the species richness is more evenly distributed among several genera. The comparison between ectomycorrhizal species richness associated with both trees in native forests and in Patagonia (Argentina) shows far fewer species in the latter, with 18 taxa for the ponderosa pine and 15 for the Douglas-fir. Epigeous species richness is clearly dominant in native Douglas-fir, whereas a more balanced relation epigeous/hypogeous richness is observed for native ponderosa pine; a similar trend was observed for Patagonian plantations. Most fungi in Patagonian Douglas-fir plantations have not been recorded in plantations elsewhere, except Suillus lakei and Thelephora terrestris, and only 56% of the fungal taxa recorded in Douglas-fir plantations around the world are known from native forests, the other taxa being new associations for this host, suggesting that new tree + ectomycorrhizal fungal taxa associations are favored in artificial situations as plantations.

  7. Tree plastic bark

    OpenAIRE

    Casado Arroyo, Carlos

    2016-01-01

    Tree plastic bark" consiste en la realización de una intervención artística en un entorno natural concreto, generando de esta manera un Site Specific(1). Como hace alusión Rosalind Krauss en sus reflexiones “La escultura en el campo expandido”(2), comenta que su origen esta claramente ligado con el concepto de monumentalidad. La escultura es un monumento, se crea para conmemorar algún hecho o personaje relevante y está realizada para una ubicación concreta. La investigación parte de la id...

  8. Save a Tree

    Science.gov (United States)

    Williams, Kathryn R.

    1999-10-01

    Starting in September 1925, JCE reproduced pictures of famous chemists or chemistry-related works of art as frontispieces. Often, the Journal included a biography or other article about the picture. The August 1945 frontispiece featured the largest cork oak in the United States. An accompanying article described the goals of the Cork Project to plant cork trees in suitable locations in the U.S., to compensate for uncertain European and African sources during World War II. The final frontispiece appeared in December 1956. To view supplementary material, please refer to JCE Online's supplementary links.

  9. The fault-tree compiler

    Science.gov (United States)

    Martensen, Anna L.; Butler, Ricky W.

    1987-01-01

    The Fault Tree Compiler Program is a new reliability tool used to predict the top event probability for a fault tree. Five different gate types are allowed in the fault tree: AND, OR, EXCLUSIVE OR, INVERT, and M OF N gates. The high level input language is easy to understand and use when describing the system tree. In addition, the use of the hierarchical fault tree capability can simplify the tree description and decrease program execution time. The current solution technique provides an answer precise (within the limits of double precision floating point arithmetic) to the five digits in the answer. The user may vary one failure rate or failure probability over a range of values and plot the results for sensitivity analyses. The solution technique is implemented in FORTRAN; the remaining program code is implemented in Pascal. The program is written to run on a Digital Corporation VAX with the VMS operation system.

  10. New Explorations for Decision Trees

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Traditionally, the decision tree method is defined and used for finding the optimal solution of a Bayesian decision problem. And it is difficult to use the decision tree method to find the sub-optimal solution, not to mention to rank alternatives. This paper discusses how to use the decision tree method for the alternative selecting and ranking.A practical case study is given to illustrate the applicability.

  11. A review of applications of tea tree oil in dermatology.

    Science.gov (United States)

    Pazyar, Nader; Yaghoobi, Reza; Bagherani, Nooshin; Kazerouni, Afshin

    2013-07-01

    Tea tree oil (TTO) is an essential oil, steam-distilled from the Australian native plant, Melaleuca alternifolia. It has a minimum content of terpinen-4-ol and a maximum content of 1, 8-cineole. Terpinen-4-ol is a major TTO component which exhibits strong antimicrobial and anti-inflammatory properties. Tea tree oil exerts antioxidant activity and has been reported to have broad-spectrum antimicrobial activity against bacterial, viral, fungal, and protozoal infections affecting skin and mucosa. Several studies have suggested the uses of TTO for the treatment of acne vulgaris, seborrheic dermatitis, and chronic gingivitis. It also accelerates the wound healing process and exhibits anti-skin cancer activity. This review opens up new horizons for dermatologists in the use of this herbal agent.

  12. Native and Non-Native English Language Teachers

    Directory of Open Access Journals (Sweden)

    Ian Walkinshaw

    2014-05-01

    Full Text Available The English language teaching industry in East and Southeast Asia subscribes to an assumption that native English-speaking teachers (NESTs are the gold standard of spoken and written language, whereas non-native English-speaking teachers (non-NESTs are inferior educators because they lack this innate linguistic skill. But does this premise correspond with the views of second language learners? This article reports on research carried out with university students in Vietnam and Japan exploring the advantages and disadvantages of learning English from NESTs and non-NESTs. Contrary to the above notion, our research illuminated a number of perceived advantages—and disadvantages—in both types of teachers. Students viewed NESTs as models of pronunciation and correct language use, as well as being repositories of cultural knowledge, but they also found NESTs poor at explaining grammar, and their different cultures created tension. Non-NESTs were perceived as good teachers of grammar, and had the ability to resort to the students’ first language when necessary. Students found classroom interaction with non-NESTs easier because of their shared culture. Non-NESTs’ pronunciation was often deemed inferior to that of NESTs, but also easier to comprehend. Some respondents advocated learning from both types of teachers, depending on learners’ proficiency and the skill being taught.

  13. Tree wavelet approximations with applications

    Institute of Scientific and Technical Information of China (English)

    XU Yuesheng; ZOU Qingsong

    2005-01-01

    We construct a tree wavelet approximation by using a constructive greedy scheme(CGS). We define a function class which contains the functions whose piecewise polynomial approximations generated by the CGS have a prescribed global convergence rate and establish embedding properties of this class. We provide sufficient conditions on a tree index set and on bi-orthogonal wavelet bases which ensure optimal order of convergence for the wavelet approximations encoded on the tree index set using the bi-orthogonal wavelet bases. We then show that if we use the tree index set associated with the partition generated by the CGS to encode a wavelet approximation, it gives optimal order of convergence.

  14. Phylogenetic trees and Euclidean embeddings.

    Science.gov (United States)

    Layer, Mark; Rhodes, John A

    2017-01-01

    It was recently observed by de Vienne et al. (Syst Biol 60(6):826-832, 2011) that a simple square root transformation of distances between taxa on a phylogenetic tree allowed for an embedding of the taxa into Euclidean space. While the justification for this was based on a diffusion model of continuous character evolution along the tree, here we give a direct and elementary explanation for it that provides substantial additional insight. We use this embedding to reinterpret the differences between the NJ and BIONJ tree building algorithms, providing one illustration of how this embedding reflects tree structures in data.

  15. The Hill and the Trees

    Institute of Scientific and Technical Information of China (English)

    王燕文

    2007-01-01

    Once there was a well-known hill here. There were many lush trees, beautiful flowers and green grasses on it. One day, the hill said to the trees proudly, “Look, how beautiful I am! But you look so ugly on my back. It must be better if I could drive you away.” One of the trees said, “You won't have beautiful and green clothing without us trees? If you leave us, you will die away.” The hill laughed and said again,”I feel very ashamed for I am staying with you together. Sooner or later I will drive you all...

  16. Tree felling: a necessary evil

    CERN Multimedia

    CERN Bulletin

    2013-01-01

    CERN started a campaign of tree felling in 2010 for safety reasons, and it will continue this year in various parts of the Meyrin site. As in previous years, the trees cut down in 2013 will be recycled and some will be replaced.   Diseased tree that had to be cut down on the Meyrin site. In association with the Geneva nature and countryside directorate (Direction générale de la nature et du paysage, DGNP), CERN commissioned the Geneva school of landscaping, engineering and architecture (Haute école du paysage, d’ingénierie et d’architecture, HEPIA) to compile an inventory of the trees on the Meyrin site. In total, 1285 trees (excluding poplars) were recorded. 75.5% of these trees were declared to be in a good state of health (i.e. 971 trees), 21.5% in a moderate state of health (276 trees) and 3% in a poor state of health (38 trees). As for the poplars, the 236 specimens recorded on the Meyrin site were judged to be too old, to...

  17. Occurrence of leguminous trees

    Energy Technology Data Exchange (ETDEWEB)

    Kirkbride, J.H.; Arkcoll, D.B.A.; Turnbull, J.W.; Magalhaes, L.M.S.; Fernandes, N.P.

    1984-01-01

    Five papers from the symposium are presented. Kirkbride, J.H. Jr.; Legumes of the cerrado. pp 23-46 (Refs. 55) A review is given. Some 548 legume species in 59 genera are listed that have been reported from cerrado vegetation. Felker, P.; Legume trees in semi-arid and arid areas. pp 47-59 (Refs. 41) A review is given of worldwide research activities. Arkcoll, D.B.; A comparison of some fast growing species suitable for woodlots in the wet tropics. pp 61-68 (Refs. 9) Studies are described near Manaus on intensive silviculture (for fuelwood production) of Eucalyptus deglupta, Cedrelinga catanaeformis (catenaeformis), Jacaranda copaia, and Inga edulis. Turnbull, J.W.; Six phyllodinous Acacia species for planting in the humid tropical lowlands. pp 69-73 (Refs. 14) Distribution, ecology, growth, and utilization are described for A. auriculiformis, A. mangium, A. aulacocarpa, A. crassicarpa, A. cincinnata, and A. polystachya. Magalhaes, L.M.S., Fernandes, N.P.; Experimental stands of leguminous trees in the Manaus region. pp 75-79 (Refs. 8) Performance up to age 20 yr of Cedrelinga catenaeformis, Dalbergia nigra, Dinizia excelsa, Dipteryx odorata, Dipteryx sp., Diplotropis sp., Eperua bijuga, Pithecellobium racemosum, Vouacapoua pallidior, and Hymenaea sp. is described.

  18. Distributed Merge Trees

    Energy Technology Data Exchange (ETDEWEB)

    Morozov, Dmitriy; Weber, Gunther

    2013-01-08

    Improved simulations and sensors are producing datasets whose increasing complexity exhausts our ability to visualize and comprehend them directly. To cope with this problem, we can detect and extract significant features in the data and use them as the basis for subsequent analysis. Topological methods are valuable in this context because they provide robust and general feature definitions. As the growth of serial computational power has stalled, data analysis is becoming increasingly dependent on massively parallel machines. To satisfy the computational demand created by complex datasets, algorithms need to effectively utilize these computer architectures. The main strength of topological methods, their emphasis on global information, turns into an obstacle during parallelization. We present two approaches to alleviate this problem. We develop a distributed representation of the merge tree that avoids computing the global tree on a single processor and lets us parallelize subsequent queries. To account for the increasing number of cores per processor, we develop a new data structure that lets us take advantage of multiple shared-memory cores to parallelize the work on a single node. Finally, we present experiments that illustrate the strengths of our approach as well as help identify future challenges.

  19. Genealogy and gene trees.

    Science.gov (United States)

    Rasmuson, Marianne

    2008-02-01

    Heredity can be followed in persons or in genes. Persons can be identified only a few generations back, but simplified models indicate that universal ancestors to all now living persons have occurred in the past. Genetic variability can be characterized as variants of DNA sequences. Data are available only from living persons, but from the pattern of variation gene trees can be inferred by means of coalescence models. The merging of lines backwards in time leads to a MRCA (most recent common ancestor). The time and place of living for this inferred person can give insights in human evolutionary history. Demographic processes are incorporated in the model, but since culture and customs are known to influence demography the models used ought to be tested against available genealogy. The Icelandic data base offers a possibility to do so and points to some discrepancies. Mitochondrial DNA and Y chromosome patterns give a rather consistent view of human evolutionary history during the latest 100 000 years but the earlier epochs of human evolution demand gene trees with longer branches. The results of such studies reveal as yet unsolved problems about the sources of our genome.

  20. The Steiner tree problem

    CERN Document Server

    Hwang, FK; Winter, P

    1992-01-01

    The Steiner problem asks for a shortest network which spans a given set of points. Minimum spanning networks have been well-studied when all connections are required to be between the given points. The novelty of the Steiner tree problem is that new auxiliary points can be introduced between the original points so that a spanning network of all the points will be shorter than otherwise possible. These new points are called Steiner points - locating them has proved problematic and research has diverged along many different avenues. This volume is devoted to the assimilation of the rich field of intriguing analyses and the consolidation of the fragments. A section has been given to each of the three major areas of interest which have emerged. The first concerns the Euclidean Steiner Problem, historically the original Steiner tree problem proposed by Jarník and Kössler in 1934. The second deals with the Steiner Problem in Networks, which was propounded independently by Hakimi and Levin and has enjoyed the most...

  1. Native arbuscular mycorrhizal fungi in the Yungas forests, Argentina.

    Science.gov (United States)

    Becerra, Alejandra G; Cabello, Marta N; Bartoloni, Norberto J

    2011-01-01

    The arbuscular mycorrhizal fungal (AMF) communities from the Yungas forests of Argentina were studied. The AMF species present in the rhizosphere of some dominant native plants (one tree: Alnus acuminata; three herbaceous species: Duchesnea indica, Oxalis conorrhiza, Trifolium aff. repens; and one shrub: Sambucus peruviana) from two sites (Quebrada del Portugués and Narváez Range) of the Yungas forests were isolated, identified and quantified during the four seasons of the year. Twenty-two AMF morphotaxa were found. Spore density of some AMF species at each site varied among seasons. The genera that most contributed to the biodiversity index were Acaulospora for Quebrada del Portugués and Glomus for Narváez Range. High diversity values were observed in the Yungas forests, particularly in the spring (rainy season). We concluded AMF differed in species composition and seasonal sporulation dynamics in the Yungas forests.

  2. Invasive alien predator causes rapid declines of native European ladybirds

    DEFF Research Database (Denmark)

    Roy, Helen E.; Adriaens, Tim; Isaac, Nick J.B.

    2012-01-01

    Aim Invasive alien species (IAS) are recognized as major drivers of biodiversity loss, but few causal relationships between IAS and species declines have been documented. In this study, we compare the distribution (Belgium and Britain) and abundance (Belgium, Britain and Switzerland) of formerly...... common and widespread native ladybirds before and after the arrival of Harmonia axyridis, a globally rapidly expanding IAS. Location Europe Methods We used generalized linear mixed-effects models (GLMMs) to assess the distribution trends of eight conspicuous and historically widespread and common species...... surveys of deciduous trees in Belgium, Britain and Switzerland. Results Five (Belgium) and seven (Britain) of eight species studied show substantial declines attributable to the arrival of H. axyridis. Indeed, the two-spot ladybird, Adalia bipunctata, declined by 30% (Belgium) and 44% (Britain) over 5...

  3. Chinese Native Speakers Counterfactuals Revisited

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    1.IntroductionI have found,in my teaching experience,that English counterfactuals are among the most diffi-cult problems for Chinese native speaker EFL learners. A recent survey of EFL teachers in Guilin,China also supports these findings. In response to the question“What do you think is the most diffi-cult for your students to learn in English”,5 6out of 71 ,or 79% said the English subjunctive verbsare. To the question“Do you think the English subjunctives are difficultfor your students”,1 0 0 % ofthe EFL ...

  4. Hybrid Parallel Contour Trees, Version 1.0

    Energy Technology Data Exchange (ETDEWEB)

    2017-01-03

    A common operation in scientific visualization is to compute and render a contour of a data set. Given a function of the form f : R^d -> R, a level set is defined as an inverse image f^-1(h) for an isovalue h, and a contour is a single connected component of a level set. The Reeb graph can then be defined to be the result of contracting each contour to a single point, and is well defined for Euclidean spaces or for general manifolds. For simple domains, the graph is guaranteed to be a tree, and is called the contour tree. Analysis can then be performed on the contour tree in order to identify isovalues of particular interest, based on various metrics, and render the corresponding contours, without having to know such isovalues a priori. This code is intended to be the first data-parallel algorithm for computing contour trees. Our implementation will use the portable data-parallel primitives provided by Nvidia’s Thrust library, allowing us to compile our same code for both GPUs and multi-core CPUs. Native OpenMP and purely serial versions of the code will likely also be included. It will also be extended to provide a hybrid data-parallel / distributed algorithm, allowing scaling beyond a single GPU or CPU.

  5. Chilling and heat requirements for flowering in temperate fruit trees.

    Science.gov (United States)

    Guo, Liang; Dai, Junhu; Ranjitkar, Sailesh; Yu, Haiying; Xu, Jianchu; Luedeling, Eike

    2014-08-01

    Climate change has affected the rates of chilling and heat accumulation, which are vital for flowering and production, in temperate fruit trees, but few studies have been conducted in the cold-winter climates of East Asia. To evaluate tree responses to variation in chill and heat accumulation rates, partial least squares regression was used to correlate first flowering dates of chestnut (Castanea mollissima Blume) and jujube (Zizyphus jujube Mill.) in Beijing, China, with daily chill and heat accumulation between 1963 and 2008. The Dynamic Model and the Growing Degree Hour Model were used to convert daily records of minimum and maximum temperature into horticulturally meaningful metrics. Regression analyses identified the chilling and forcing periods for chestnut and jujube. The forcing periods started when half the chilling requirements were fulfilled. Over the past 50 years, heat accumulation during tree dormancy increased significantly, while chill accumulation remained relatively stable for both species. Heat accumulation was the main driver of bloom timing, with effects of variation in chill accumulation negligible in Beijing’s cold-winter climate. It does not seem likely that reductions in chill will have a major effect on the studied species in Beijing in the near future. Such problems are much more likely for trees grown in locations that are substantially warmer than their native habitats, such as temperate species in the subtropics and tropics.

  6. Chilling and heat requirements for flowering in temperate fruit trees

    Science.gov (United States)

    Guo, Liang; Dai, Junhu; Ranjitkar, Sailesh; Yu, Haiying; Xu, Jianchu; Luedeling, Eike

    2014-08-01

    Climate change has affected the rates of chilling and heat accumulation, which are vital for flowering and production, in temperate fruit trees, but few studies have been conducted in the cold-winter climates of East Asia. To evaluate tree responses to variation in chill and heat accumulation rates, partial least squares regression was used to correlate first flowering dates of chestnut ( Castanea mollissima Blume) and jujube ( Zizyphus jujube Mill.) in Beijing, China, with daily chill and heat accumulation between 1963 and 2008. The Dynamic Model and the Growing Degree Hour Model were used to convert daily records of minimum and maximum temperature into horticulturally meaningful metrics. Regression analyses identified the chilling and forcing periods for chestnut and jujube. The forcing periods started when half the chilling requirements were fulfilled. Over the past 50 years, heat accumulation during tree dormancy increased significantly, while chill accumulation remained relatively stable for both species. Heat accumulation was the main driver of bloom timing, with effects of variation in chill accumulation negligible in Beijing's cold-winter climate. It does not seem likely that reductions in chill will have a major effect on the studied species in Beijing in the near future. Such problems are much more likely for trees grown in locations that are substantially warmer than their native habitats, such as temperate species in the subtropics and tropics.

  7. Native Chicken Production in Indonesia: A Review

    Directory of Open Access Journals (Sweden)

    C. Hidayat

    2015-02-01

    Full Text Available Indonesia is a country rich in native chicken genetic resources. There are 31 native chicken breed in Indonesia. Native chicken farming was developed for decades. In early period of 1907’s, mostly farmers reared their native chicken by traditional system (about 80%. In 1980s until now, the number of native chicken farmers which rear native chicken by semi intensive and intensive system have been increasing. These rearing system changing have significantly increased the native chicken productivity. The major constraints for the development of native chicken i.e. low growth rate, risks of high mortality, low egg production. Many research results stated that improving in breeding, feeding and management aspect will increase native chicken production. The information and data contained in this paper is the result of study literature for scientific papers, either in the form of journals, books, or proceedings, and livestock statistics books. This paper is made to support the development of native chickens in Indonesia.

  8. Sussing Merger Trees: A proposed Merger Tree data format

    CERN Document Server

    Thomas, Peter A; Tweed, Dylan; Benson, Andrew J; Croton, Darren; Elahi, Pascal; Henriques, Bruno; Iliev, Ilian T; Knebe, Alexander; Lux, Hanni; Mao, Yao-Yuan; Neyrinck, Mark; Pearce, Frazer R; Rodriguez-Gomez, Vicente; Schneider, Aurel; Srisawat, Chaichalit

    2015-01-01

    We propose a common terminology for use in describing both temporal merger trees and spatial structure trees for dark-matter halos. We specify a unified data format in HDF5 and provide example I/O routines in C, FORTRAN and PYTHON.

  9. DIF Trees: Using Classification Trees to Detect Differential Item Functioning

    Science.gov (United States)

    Vaughn, Brandon K.; Wang, Qiu

    2010-01-01

    A nonparametric tree classification procedure is used to detect differential item functioning for items that are dichotomously scored. Classification trees are shown to be an alternative procedure to detect differential item functioning other than the use of traditional Mantel-Haenszel and logistic regression analysis. A nonparametric…

  10. Tree Decomposition based Steiner Tree Computation over Large Graphs

    OpenAIRE

    2013-01-01

    In this paper, we present an exact algorithm for the Steiner tree problem. The algorithm is based on certain pre-computed index structures. Our algorithm offers a practical solution for the Steiner tree problems on graphs of large size and bounded number of terminals.

  11. Effects of tree shelterbelts on the hydrology of upland areas

    Science.gov (United States)

    Solloway, I.; Frogbrook, Z. L.; Jackson, B. M.; Marshall, M. R.; McIntyre, N. M.; Reynolds, B.; Wheater, H. S.; Chell, J.; Christen, B.

    2009-04-01

    Recent large flood events in the UK have focused attention on the effects of agricultural intensification and de-intensification on flood risk. Possible detrimental factors for these floods are thought to be the degradation of soil structure through compaction from grazing animals and agricultural machinery; while possible ameliorating factors may be the re-introduction of natural landscape features such as woodland and wetlands. In order to address this issue in an upland setting a multi-scale experimental programme has been implemented at Pontbren, a sheep-farmed headwater catchment of the River Severn, UK. Primary aims are to develop understanding of the processes governing flood generation and the associated impacts of land management practices, and to bridge the gap between process understanding and ability to predict effects on downstream flooding. An integral component of this is to determine the role that native, broadleaf trees, planted as shelterbelts on intensively grazed pasture, may have in the reduction of flooding. Effects of trees on soil physical properties, soil moisture status and rainfall interception are investigated, including any ‘rain-shadow' and edge effects. Three ungrazed tree strips, plus one woodland edge, have been instrumented with clusters of tensiometers, plus throughfall and stemflow collectors. Soil moisture measurements have been made with a neutron probe, and tracer tests and permeameter tests have been carried out. Overland flow has been collected at one tree site. Comparisons of soil hydraulic properties show significant increases in saturated moisture content and hydraulic conductivity of soil under trees compared to adjacent improved pasture. These effects, combined with increased interception and water use by the trees, have led to differences in soil moisture, with the soil under the trees being considerably drier than that under the pasture. The results show seasonal variation. Dye tracer tests reveal preferential flow

  12. Effects of Invasive Winter Moth Defoliation on Tree Radial Growth in Eastern Massachusetts, USA

    Science.gov (United States)

    Simmons, Michael J.; Lee, Thomas D.; Ducey, Mark J.; Elkinton, Joseph S.; Boettner, George H.; Dodds, Kevin J.

    2014-01-01

    Winter moth, Operophtera brumata L. (Lepidoptera: Geometridae), has been defoliating hardwood trees in eastern Massachusetts since the 1990s. Native to Europe, winter moth has also been detected in Rhode Island, Connecticut, eastern Long Island (NY), New Hampshire, and Maine. Individual tree impacts of winter moth defoliation in New England are currently unknown. Using dendroecological techniques, this study related annual radial growth of individual host (Quercus spp. and Acer spp.) trees to detailed defoliation estimates. Winter moth defoliation was associated with up to a 47% reduction in annual radial growth of Quercus trees. Latewood production of Quercus was reduced by up to 67% in the same year as defoliation, while earlywood production was reduced by up to 24% in the year following defoliation. Winter moth defoliation was not a strong predictor of radial growth in Acer species. This study is the first to document impacts of novel invasions of winter moth into New England. PMID:26462685

  13. Effects of Invasive Winter Moth Defoliation on Tree Radial Growth in Eastern Massachusetts, USA

    Directory of Open Access Journals (Sweden)

    Michael J. Simmons

    2014-04-01

    Full Text Available Winter moth, Operophtera brumata L. (Lepidoptera: Geometridae, has been defoliating hardwood trees in eastern Massachusetts since the 1990s. Native to Europe, winter moth has also been detected in Rhode Island, Connecticut, eastern Long Island (NY, New Hampshire, and Maine. Individual tree impacts of winter moth defoliation in New England are currently unknown. Using dendroecological techniques, this study related annual radial growth of individual host (Quercus spp. and Acer spp. trees to detailed defoliation estimates. Winter moth defoliation was associated with up to a 47% reduction in annual radial growth of Quercus trees. Latewood production of Quercus was reduced by up to 67% in the same year as defoliation, while earlywood production was reduced by up to 24% in the year following defoliation. Winter moth defoliation was not a strong predictor of radial growth in Acer species. This study is the first to document impacts of novel invasions of winter moth into New England.

  14. Drivers of Tree Growth, Mortality and Harvest Preferences in Species-Rich Plantations for Smallholders and Communities in the Tropics

    Science.gov (United States)

    Nguyen, Huong; Vanclay, Jerome; Herbohn, John; Firn, Jennifer

    2016-01-01

    There is growing interest in multi-species tropical plantations but little information exists to guide their design and silviculture. The Rainforestation Farming system is the oldest tropical polyculture planting system in the Philippines and provides a unique opportunity to understand the underlying processes affecting tree performance within diverse plantings. Data collected from 85 plots distributed across the 18 mixed-species plantations in the Philippines was used to identify the factors influencing growth, probability of harvest, and death of trees in these complex plantings. The 18 sites (aged from 6 to 11 years at time of first measurement) were measured on three occasions over a 6-year period. We used data from the first period of data collection to develop models predicting harvesting probability and growth of trees in the second period. We found little evidence that tree species diversity had an effect on tree growth and tree loss at the community level, although a negative effect was found on tree growth of specific species such as Parashorea plicata and Swietenia macrophylla. While tree density of stands at age 10+ years (more than 1000 trees/ha with diameter > 5cm) did not have an impact on growth, growth rates were decreasing in stands with a high basal area. Tree size in the first period of measure was a good predictor for both tree growth and tree status in the next period, with larger trees tending to grow faster and having a greater chance of being harvested, and a lower possibility of mortality than smaller trees. Shade-intolerant trees were both more likely to be harvested, and had a higher probability of death, than shade-tolerant individuals. Native species and exotic species were equally likely to have been lost from the plots between measurement periods. However, shade-tolerant native trees were likely to grow faster than the others at age 10+ years. Our findings suggest that species traits (e.g. shade tolerance) could play an important

  15. Trees and Shrubs for Overhead Utility Easements

    OpenAIRE

    Appleton, Bonnie Lee, 1948-2012; French, Sue (Sue C.); Johnson-Asnicar, Brenda; Relf, Diane; Day, Susan D.; Nunnally, Richard, 1947-; Vest, John

    2009-01-01

    Trees are one of the major causes of power outages in areas of overhead utility lines due to direct tree contact with lines, or to trees or tree limbs falling on the lines. This publication covers conflict resolution options and tree selection and planting when dealing with landscaping around power lines.

  16. Direct vs. Microclimate-Driven Effects of Tree Species Diversity on Litter Decomposition in Young Subtropical Forest Stands.

    Science.gov (United States)

    Seidelmann, Katrin N; Scherer-Lorenzen, Michael; Niklaus, Pascal A

    2016-01-01

    Effects of tree species diversity on decomposition can operate via a multitude of mechanism, including alterations of microclimate by the forest canopy. Studying such effects in natural settings is complicated by the fact that topography also affects microclimate and thus decomposition, so that effects of diversity are more difficult to isolate. Here, we quantified decomposition rates of standard litter in young subtropical forest stands, separating effects of canopy tree species richness and topography, and quantifying their direct and micro-climate-mediated components. Our litterbag study was carried out at two experimental sites of a biodiversity-ecosystem functioning field experiment in south-east China (BEF-China). The field sites display strong topographical heterogeneity and were planted with tree communities ranging from monocultures to mixtures of 24 native subtropical tree species. Litter bags filled with senescent leaves of three native tree species were placed from Nov. 2011 to Oct. 2012 on 134 plots along the tree species diversity gradient. Topographic features were measured for all and microclimate in a subset of plots. Stand species richness, topography and microclimate explained important fractions of the variations in litter decomposition rates, with diversity and topographic effects in part mediated by microclimatic changes. Tree stands were 2-3 years old, but nevertheless tree species diversity explained more variation (54.3%) in decomposition than topography (7.7%). Tree species richness slowed litter decomposition, an effect that slightly depended on litter species identity. A large part of the variance in decomposition was explained by tree species composition, with the presence of three tree species playing a significant role. Microclimate explained 31.4% of the variance in decomposition, and was related to lower soil moisture. Within this microclimate effect, species diversity (without composition) explained 8.9% and topography 34.4% of

  17. Encrusted pyelitis of native kidneys.

    Science.gov (United States)

    Hertig, A; Duvic, C; Chretien, Y; Jungers, P; Grünfeld, J P; Rieu, P

    2000-06-01

    This study reports the first four cases of encrusted pyelitis involving native kidneys. The clinical features, management, and outcome of these patients were analyzed. Predisposing factors were underlying urologic disease and/or urologic manipulations, debilitating diseases, hospitalization, and prolonged antibiotic therapies. Presenting symptoms were renal failure in three patients with ureteroileal urinary diversion and manifestations of cystitis in one patient. Computed tomography scan of the urinary tract was critical for diagnosis. Presence of struvite was demonstrated by crystalluria and infrared spectrophotometry analysis of the encrusted material. Corynebacterium urealyticum urinary infection was identified in one case. Surgery (one patient) and palliative ureteral diversion (one patient), respectively, led to death and end-stage renal failure. Successful dissolution of encrusted pyelitis was obtained in two patients treated with intravenous vancomycin and local acidification of the renal collecting system. Clinical observation shows that encrusted pyelitis is a threatening disorder that destroys the native kidneys and may lead to end-stage renal failure. Successful treatment of the disease by chemolysis and antibiotics depends on correct and early diagnosis. Diagnosis required recognition of the predisposing factors, computed tomography imaging of the urinary tract, crystalluria, and identification of urea-splitting bacteria with prolonged culture on selective medium.

  18. Reconstructing Native American population history.

    Science.gov (United States)

    Reich, David; Patterson, Nick; Campbell, Desmond; Tandon, Arti; Mazieres, Stéphane; Ray, Nicolas; Parra, Maria V; Rojas, Winston; Duque, Constanza; Mesa, Natalia; García, Luis F; Triana, Omar; Blair, Silvia; Maestre, Amanda; Dib, Juan C; Bravi, Claudio M; Bailliet, Graciela; Corach, Daniel; Hünemeier, Tábita; Bortolini, Maria Cátira; Salzano, Francisco M; Petzl-Erler, María Luiza; Acuña-Alonzo, Victor; Aguilar-Salinas, Carlos; Canizales-Quinteros, Samuel; Tusié-Luna, Teresa; Riba, Laura; Rodríguez-Cruz, Maricela; Lopez-Alarcón, Mardia; Coral-Vazquez, Ramón; Canto-Cetina, Thelma; Silva-Zolezzi, Irma; Fernandez-Lopez, Juan Carlos; Contreras, Alejandra V; Jimenez-Sanchez, Gerardo; Gómez-Vázquez, Maria José; Molina, Julio; Carracedo, Angel; Salas, Antonio; Gallo, Carla; Poletti, Giovanni; Witonsky, David B; Alkorta-Aranburu, Gorka; Sukernik, Rem I; Osipova, Ludmila; Fedorova, Sardana A; Vasquez, René; Villena, Mercedes; Moreau, Claudia; Barrantes, Ramiro; Pauls, David; Excoffier, Laurent; Bedoya, Gabriel; Rothhammer, Francisco; Dugoujon, Jean-Michel; Larrouy, Georges; Klitz, William; Labuda, Damian; Kidd, Judith; Kidd, Kenneth; Di Rienzo, Anna; Freimer, Nelson B; Price, Alkes L; Ruiz-Linares, Andrés

    2012-08-16

    The peopling of the Americas has been the subject of extensive genetic, archaeological and linguistic research; however, central questions remain unresolved. One contentious issue is whether the settlement occurred by means of a single migration or multiple streams of migration from Siberia. The pattern of dispersals within the Americas is also poorly understood. To address these questions at a higher resolution than was previously possible, we assembled data from 52 Native American and 17 Siberian groups genotyped at 364,470 single nucleotide polymorphisms. Here we show that Native Americans descend from at least three streams of Asian gene flow. Most descend entirely from a single ancestral population that we call 'First American'. However, speakers of Eskimo-Aleut languages from the Arctic inherit almost half their ancestry from a second stream of Asian gene flow, and the Na-Dene-speaking Chipewyan from Canada inherit roughly one-tenth of their ancestry from a third stream. We show that the initial peopling followed a southward expansion facilitated by the coast, with sequential population splits and little gene flow after divergence, especially in South America. A major exception is in Chibchan speakers on both sides of the Panama isthmus, who have ancestry from both North and South America.

  19. Reconstructing Native American Population History

    Science.gov (United States)

    Reich, David; Patterson, Nick; Campbell, Desmond; Tandon, Arti; Mazieres, Stéphane; Ray, Nicolas; Parra, Maria V.; Rojas, Winston; Duque, Constanza; Mesa, Natalia; García, Luis F.; Triana, Omar; Blair, Silvia; Maestre, Amanda; Dib, Juan C.; Bravi, Claudio M.; Bailliet, Graciela; Corach, Daniel; Hünemeier, Tábita; Bortolini, Maria-Cátira; Salzano, Francisco M.; Petzl-Erler, María Luiza; Acuña-Alonzo, Victor; Aguilar-Salinas, Carlos; Canizales-Quinteros, Samuel; Tusié-Luna, Teresa; Riba, Laura; Rodríguez-Cruz, Maricela; Lopez-Alarcón, Mardia; Coral-Vazquez, Ramón; Canto-Cetina, Thelma; Silva-Zolezzi, Irma; Fernandez-Lopez, Juan Carlos; Contreras, Alejandra V.; Jimenez-Sanchez, Gerardo; Gómez-Vázquez, María José; Molina, Julio; Carracedo, Ángel; Salas, Antonio; Gallo, Carla; Poletti, Giovanni; Witonsky, David B.; Alkorta-Aranburu, Gorka; Sukernik, Rem I.; Osipova, Ludmila; Fedorova, Sardana; Vasquez, René; Villena, Mercedes; Moreau, Claudia; Barrantes, Ramiro; Pauls, David; Excoffier, Laurent; Bedoya, Gabriel; Rothhammer, Francisco; Dugoujon, Jean Michel; Larrouy, Georges; Klitz, William; Labuda, Damian; Kidd, Judith; Kidd, Kenneth; Rienzo, Anna Di; Freimer, Nelson B.; Price, Alkes L.; Ruiz-Linares, Andrés

    2013-01-01

    The peopling of the Americas has been the subject of extensive genetic, archaeological and linguistic research; however, central questions remain unresolved1–5. One contentious issue is whether the settlement occurred via a single6–8 or multiple streams of migration from Siberia9–15. The pattern of dispersals within the Americas is also poorly understood. To address these questions at higher resolution than was previously possible, we assembled data from 52 Native American and 17 Siberian groups genotyped at 364,470 single nucleotide polymorphisms. We show that Native Americans descend from at least three streams of Asian gene flow. Most descend entirely from a single ancestral population that we call “First American”. However, speakers of Eskimo-Aleut languages from the Arctic inherit almost half their ancestry from a second stream of Asian gene flow, and the Na-Dene-speaking Chipewyan from Canada inherit roughly one-tenth of their ancestry from a third stream. We show that the initial peopling followed a southward expansion facilitated by the coast, with sequential population splits and little gene flow after divergence, especially in South America. A major exception is in Chibchan-speakers on both sides of the Panama Isthmus, who have ancestry from both North and South America. PMID:22801491

  20. Influence of cerrado fragments in the distribution of mites in rubber tree crop; Influencia de fragmentos de cerrado na distribuicao de acaros em seringal

    Energy Technology Data Exchange (ETDEWEB)

    Demite, Peterson R. [UNESP, Sao Jose do Rio Preto, SP (Brazil). Programa de Pos-graduacao em Biologia Animal; Plantacoes E. Michelin Ltda., Itiquira, MT (Brazil)]. E-mail: peterson_demite@yahoo.com.br; Feres, Reinaldo J.F. [UNESP, Sao Jose do Rio Preto, SP (Brazil). Dept. de Zoologia e Botanica]. E-mail: reinaldo@ibilce.unesp.br

    2008-03-15

    The aim of this study was to verify whether fragments of cerrado influence the composition of the mite fauna on rubber trees. Five transects distant 50 m, being the first in the edge near the native areas and the last 200 m inside the crop, were established in each rubber tree crop in southern State of Mato Grosso. In each transect five plants were chosen, and seven leaves were collected from each plant. During one year, 25 quantitative samplings were conducted in two rubber tree crops. The lowest number of phytophagous mites occurred in the transect closer to the native vegetation, and the highest number, in the most distant from the native vegetation. The largest diversity was also observed in the transect closer to the neighboring vegetation. Ten species of predatory mites were also registered in neighboring native areas. These data suggest the movement of predatory mites from the native areas to the mono culture. These natural areas can possibly supply alternative food and habitat for natural enemies of phytophagous mites in the period of food scarceness in the rubber tree crop. The presence of native areas close to culture areas should be taken into account in the elaboration of programs of ecological management of pests. (author)

  1. Evidence of cross-reactivity between olive, ash, privet, and Russian olive tree pollen allergens.

    Science.gov (United States)

    Kernerman, S M; McCullough, J; Green, J; Ownby, D R

    1992-12-01

    In a clinical investigation, 103 Michigan residents with symptoms suggestive of allergic rhinitis or asthma were skin tested with olive (Olea europaea) pollen extract. Nineteen had positive reactions. Since the olive tree is not native to nor grown in Michigan, this study was undertaken to determine whether the skin test reactivity was the result of cross-reactivity among tree pollen allergens. ELISAs were developed to measure olive, ash (Fraxinus americana), privet (Ligustrum vulgare), and Russian olive (Elaeagnus angustifolia) specific IgE antibodies. Inhibition studies were performed to determine whether pollen extracts from each of these tree species could inhibit IgE antibody binding to olive extracts. Eleven of the 19 skin test-positive patients were olive-ELISA positive, eight either were ELISA-positive to ash, seven to privet and ten to Russian olive. There were significant correlations between the ELISA results to olive and each of the other three pollens. The inhibition studies demonstrated that all three of the tree pollens were capable of inhibiting the binding of IgE to olive extract in a dose-response fashion. IgE-immunoblot studies demonstrated several proteins common to olive, ash, and privet. Twelve of the olive skin test-positive patients were contacted and 75% were exposed to one or more of the studied trees in their yards. Five patients had traveled to areas where olive trees are grown. We conclude that there is a high degree of cross-reactivity among allergens from native Michigan trees and from olive trees. This cross-reactivity is the most likely reason for skin test reactivity to olive pollen extract in Michigan.

  2. Adjustable chain trees for proteins

    DEFF Research Database (Denmark)

    Winter, Pawel; Fonseca, Rasmus

    2012-01-01

    A chain tree is a data structure for changing protein conformations. It enables very fast detection of clashes and free energy potential calculations. A modified version of chain trees that adjust themselves to the changing conformations of folding proteins is introduced. This results in much...

  3. Temperature and tree growth [editorial

    Science.gov (United States)

    Michael G. Ryan

    2010-01-01

    Tree growth helps US forests take up 12% of the fossil fuels emitted in the USA (Woodbury et al. 2007), so predicting tree growth for future climates matters. Predicting future climates themselves is uncertain, but climate scientists probably have the most confidence in predictions for temperature. Temperatures are projected to rise by 0.2 °C in the next two decades,...

  4. The Harary index of trees

    CERN Document Server

    c, Aleksandar Ili\\'; Feng, Lihua

    2011-01-01

    The Harary index of a graph $G$ is recently introduced topological index, defined on the reverse distance matrix as $H(G)=\\sum_{u,v \\in V(G)}\\frac{1}{d(u,v)}$, where $d(u,v)$ is the length of the shortest path between two distinct vertices $u$ and $v$. We present the partial ordering of starlike trees based on the Harary index and we describe the trees with the second maximal and the second minimal Harary index. In this paper, we investigate the Harary index of trees with $k$ pendent vertices and determine the extremal trees with maximal Harary index. We also characterize the extremal trees with maximal Harary index with respect to the number of vertices of degree two, matching number, independence number, domination number, radius and diameter. In addition, we characterize the extremal trees with minimal Harary index and given maximum degree. We concluded that in all presented classes, the trees with maximal Harary index are exactly those trees with the minimal Wiener index, and vice versa.

  5. The Tree of Industrial Life

    DEFF Research Database (Denmark)

    Andersen, Esben Sloth

    2002-01-01

    The purpose of this paper is to bring forth an interaction between evolutionary economics and industrial systematics. The suggested solution is to reconstruct the "family tree" of the industries. Such a tree is based on similarities, but it may also reflect the evolutionary history in industries ...

  6. Tree Hydraulics: How Sap Rises

    Science.gov (United States)

    Denny, Mark

    2012-01-01

    Trees transport water from roots to crown--a height that can exceed 100 m. The physics of tree hydraulics can be conveyed with simple fluid dynamics based upon the Hagen-Poiseuille equation and Murray's law. Here the conduit structure is modelled as conical pipes and as branching pipes. The force required to lift sap is generated mostly by…

  7. Tree Hydraulics: How Sap Rises

    Science.gov (United States)

    Denny, Mark

    2012-01-01

    Trees transport water from roots to crown--a height that can exceed 100 m. The physics of tree hydraulics can be conveyed with simple fluid dynamics based upon the Hagen-Poiseuille equation and Murray's law. Here the conduit structure is modelled as conical pipes and as branching pipes. The force required to lift sap is generated mostly by…

  8. NativeView: A Geospatial Curriculum for Native Nation Building

    Science.gov (United States)

    Rattling Leaf, J.

    2007-12-01

    In the spirit of collaboration and reciprocity, James Rattling Leaf of Sinte Gleska University on the Rosebud Reservation of South Dakota will present recent developments, experiences, insights and a vision for education in Indian Country. As a thirty-year young institution, Sinte Gleska University is founded by a strong vision of ancestral leadership and the values of the Lakota Way of Life. Sinte Gleska University (SGU) has initiated the development of a Geospatial Education Curriculum project. NativeView: A Geospatial Curriculum for Native Nation Building is a two-year project that entails a disciplined approach towards the development of a relevant Geospatial academic curriculum. This project is designed to meet the educational and land management needs of the Rosebud Lakota Tribe through the utilization of Geographic Information Systems (GIS), Remote Sensing (RS) and Global Positioning Systems (GPS). In conjunction with the strategy and progress of this academic project, a formal presentation and demonstration of the SGU based Geospatial software RezMapper software will exemplify an innovative example of state of the art information technology. RezMapper is an interactive CD software package focused toward the 21 Lakota communities on the Rosebud Reservation that utilizes an ingenious concept of multimedia mapping and state of the art data compression and presentation. This ongoing development utilizes geographic data, imagery from space, historical aerial photography and cultural features such as historic Lakota documents, language, song, video and historical photographs in a multimedia fashion. As a tangible product, RezMapper will be a project deliverable tool for use in the classroom and to a broad range of learners.

  9. Random Projection Trees Revisited

    CERN Document Server

    Dhesi, Aman

    2010-01-01

    The Random Projection Tree structures proposed in [Freund-Dasgupta STOC08] are space partitioning data structures that automatically adapt to various notions of intrinsic dimensionality of data. We prove new results for both the RPTreeMax and the RPTreeMean data structures. Our result for RPTreeMax gives a near-optimal bound on the number of levels required by this data structure to reduce the size of its cells by a factor $s \\geq 2$. We also prove a packing lemma for this data structure. Our final result shows that low-dimensional manifolds have bounded Local Covariance Dimension. As a consequence we show that RPTreeMean adapts to manifold dimension as well.

  10. Tree Quantum Field Theory

    CERN Document Server

    Gurau, R; Rivasseau, V

    2008-01-01

    We propose a new formalism for quantum field theory which is neither based on functional integrals, nor on Feynman graphs, but on marked trees. This formalism is constructive, i.e. it computes correlation functions through convergent rather than divergent expansions. It applies both to Fermionic and Bosonic theories. It is compatible with the renormalization group, and it allows to define non-perturbatively {\\it differential} renormalization group equations. It accommodates any general stable polynomial Lagrangian. It can equally well treat noncommutative models or matrix models such as the Grosse-Wulkenhaar model. Perhaps most importantly it removes the space-time background from its central place in QFT, paving the way for a nonperturbative definition of field theory in noninteger dimension.

  11. Rubbery Polya Tree.

    Science.gov (United States)

    Nieto-Barajas, Luis E; Müller, Peter

    2012-03-01

    Polya trees (PT) are random probability measures which can assign probability 1 to the set of continuous distributions for certain specifications of the hyperparameters. This feature distinguishes the PT from the popular Dirichlet process (DP) model which assigns probability 1 to the set of discrete distributions. However, the PT is not nearly as widely used as the DP prior. Probably the main reason is an awkward dependence of posterior inference on the choice of the partitioning subsets in the definition of the PT. We propose a generalization of the PT prior that mitigates this undesirable dependence on the partition structure, by allowing the branching probabilities to be dependent within the same level. The proposed new process is not a PT anymore. However, it is still a tail-free process and many of the prior properties remain the same as those for the PT.

  12. Fires on trees

    CERN Document Server

    Bertoin, Jean

    2010-01-01

    We consider random dynamics on the edges of a uniform Cayley tree with $n$ vertices, in which edges are either inflammable, fireproof, or burt. Every inflammable edge is replaced by a fireproof edge at unit rate, while fires start at smaller rate $n^{-\\alpha}$ on each inflammable edge, then propagate through the neighboring inflammable edges and are only stopped at fireproof edges. A vertex is called fireproof when all its adjacent edges are fireproof. We show that as $n\\to \\infty$, the density of fireproof vertices converges to 1 when $\\alpha>1/2$, to 0 when $\\alpha<1/2$, and to some non-degenerate random variable when $\\alpha=1/2$. We further study the connectivity of the fireproof forest, in particular the existence of a giant component.

  13. Immigration, education and native wage inequality

    OpenAIRE

    Lumpe, Christian; Weigert, Benjamin

    2010-01-01

    In this paper we analyse the effect of immigration on the labour market prospects for different skill groups among natives. We develop a model of endogenous labour supply in which immigration affects educational decisions of natives. We argue that the distributional consequences of immigration with respect to native between-skill-group inequality are ambiguous in general and crucially depend on the host country's level of educational attainment. We show that this result is robust irrespective...

  14. Walking in Balance: Native American Recovery Programmes

    Directory of Open Access Journals (Sweden)

    Suzanne Owen

    2014-10-01

    Full Text Available This article reviews Native American ritual practices, frameworks and key concepts employed by several substance abuse treatments centres in the U.S. and Canada. It also examines the way Alcoholics Anonymous’ Twelve Step programme has been modified to attract and serve the needs of Native Americans and First Nations and its potential impact on the ritual practices. Native concepts of wellbeing are highlighted and linked to the idea of living in “balance”.

  15. TREE DECOMPOSITIONS OF MULTIGRAPHS

    Institute of Scientific and Technical Information of China (English)

    SHI Minyong

    1999-01-01

    For a graph G, ifE(G) can be partitioned into several pairwise disjointsets as { E1, E2,……,El} such thatthe subgraph induced by Ei is a tree of orderki, (i=1,2, ……, l), then G is said to have a {k1,k2,……, kl}-tree-decomposition, denoted by {k1,k2,……, kl}∈G.For k≥1 and l≥0, a collection(G)(k,l) is the setof multigraphs such that G∈(G)(k,l) if and only if ε(G) = k(|G|-1)-l and ε(H)≤max{(k-1)(|H|-1), k(|H|-1)-l} for any subgraph H of G.We prove that (1) If k≥2, 0≤l≤3 and G∈(G)(k,l) of order n≥l+1, then {n,n,……, n-l}∈ G. (2) If k≥2 and G∈(G)(k,2) oforder n≥3, then {n,n,……, n,n-2}∈G and {n,n,……, n,n-1,n-1}∈G. (3) If k3 and G∈(G)(k,3) oforder n≥4, then {n,n,……, n,n-3}∈G ,{ n,n,……, n,n-1,n-2}∈ G and {n,n, ……, n,n-1,n-1,n-1}∈G.

  16. Tree species, tree genotypes and tree genotypic diversity levels affect microbe-mediated soil ecosystem functions in a subtropical forest

    OpenAIRE

    Purahong, Witoon; Durka, Walter; Fischer, Markus; Dommert, Sven; Schöps, Ricardo; Buscot, François; Wubet, Tesfaye

    2016-01-01

    Tree species identity and tree genotypes contribute to the shaping of soil microbial communities. However, knowledge about how these two factors influence soil ecosystem functions is still lacking. Furthermore, in forest ecosystems tree genotypes co-occur and interact with each other, thus the effects of tree genotypic diversity on soil ecosystem functions merit attention. Here we investigated the effects of tree species, tree genotypes and genotypic diversity levels, alongside soil physicoch...

  17. Modelling tree biomasses in Finland

    Energy Technology Data Exchange (ETDEWEB)

    Repola, J.

    2013-06-01

    Biomass equations for above- and below-ground tree components of Scots pine (Pinus sylvestris L), Norway spruce (Picea abies [L.] Karst) and birch (Betula pendula Roth and Betula pubescens Ehrh.) were compiled using empirical material from a total of 102 stands. These stands (44 Scots pine, 34 Norway spruce and 24 birch stands) were located mainly on mineral soil sites representing a large part of Finland. The biomass models were based on data measured from 1648 sample trees, comprising 908 pine, 613 spruce and 127 birch trees. Biomass equations were derived for the total above-ground biomass and for the individual tree components: stem wood, stem bark, living and dead branches, needles, stump, and roots, as dependent variables. Three multivariate models with different numbers of independent variables for above-ground biomass and one for below-ground biomass were constructed. Variables that are normally measured in forest inventories were used as independent variables. The simplest model formulations, multivariate models (1) were mainly based on tree diameter and height as independent variables. In more elaborated multivariate models, (2) and (3), additional commonly measured tree variables such as age, crown length, bark thickness and radial growth rate were added. Tree biomass modelling includes consecutive phases, which cause unreliability in the prediction of biomass. First, biomasses of sample trees should be determined reliably to decrease the statistical errors caused by sub-sampling. In this study, methods to improve the accuracy of stem biomass estimates of the sample trees were developed. In addition, the reliability of the method applied to estimate sample-tree crown biomass was tested, and no systematic error was detected. Second, the whole information content of data should be utilized in order to achieve reliable parameter estimates and applicable and flexible model structure. In the modelling approach, the basic assumption was that the biomasses of

  18. Tree Coding of Bilevel Images

    DEFF Research Database (Denmark)

    Martins, Bo; Forchhammer, Søren

    1998-01-01

    Presently, sequential tree coders are the best general purpose bilevel image coders and the best coders of halftoned images. The current ISO standard, Joint Bilevel Image Experts Group (JBIG), is a good example. A sequential tree coder encodes the data by feeding estimates of conditional...... probabilities to an arithmetic coder. The conditional probabilities are estimated from co-occurrence statistics of past pixels, the statistics are stored in a tree. By organizing the code length calculations properly, a vast number of possible models (trees) reflecting different pixel orderings can...... is one order of magnitude slower than JBIG, obtains excellent and highly robust compression performance. A multipass free tree coding scheme produces superior compression results for all test images. A multipass free template coding scheme produces significantly better results than JBIG for difficult...

  19. Quantum Computation and Decision Trees

    CERN Document Server

    Farhi, E; Farhi, Edward; Gutmann, Sam

    1998-01-01

    Many interesting computational problems can be reformulated in terms of decision trees. A natural classical algorithm is to then run a random walk on the tree, starting at the root, to see if the tree contains a node n levels from the root. We devise a quantum mechanical algorithm that evolves a state, initially localized at the root, through the tree. We prove that if the classical strategy succeeds in reaching level n in time polynomial in n, then so does the quantum algorithm. Moreover, we find examples of trees for which the classical algorithm requires time exponential in n, but for which the quantum algorithm succeeds in polynomial time. The examples we have so far, however, could also be solved in polynomial time by different classical algorithms.

  20. DNA barcoding the native flowering plants and conifers of Wales.

    Directory of Open Access Journals (Sweden)

    Natasha de Vere

    Full Text Available We present the first national DNA barcode resource that covers the native flowering plants and conifers for the nation of Wales (1143 species. Using the plant DNA barcode markers rbcL and matK, we have assembled 97.7% coverage for rbcL, 90.2% for matK, and a dual-locus barcode for 89.7% of the native Welsh flora. We have sampled multiple individuals for each species, resulting in 3304 rbcL and 2419 matK sequences. The majority of our samples (85% are from DNA extracted from herbarium specimens. Recoverability of DNA barcodes is lower using herbarium specimens, compared to freshly collected material, mostly due to lower amplification success, but this is balanced by the increased efficiency of sampling species that have already been collected, identified, and verified by taxonomic experts. The effectiveness of the DNA barcodes for identification (level of discrimination is assessed using four approaches: the presence of a barcode gap (using pairwise and multiple alignments, formation of monophyletic groups using Neighbour-Joining trees, and sequence similarity in BLASTn searches. These approaches yield similar results, providing relative discrimination levels of 69.4 to 74.9% of all species and 98.6 to 99.8% of genera using both markers. Species discrimination can be further improved using spatially explicit sampling. Mean species discrimination using barcode gap analysis (with a multiple alignment is 81.6% within 10×10 km squares and 93.3% for 2×2 km squares. Our database of DNA barcodes for Welsh native flowering plants and conifers represents the most complete coverage of any national flora, and offers a valuable platform for a wide range of applications that require accurate species identification.

  1. DNA barcoding the native flowering plants and conifers of Wales.

    Science.gov (United States)

    de Vere, Natasha; Rich, Tim C G; Ford, Col R; Trinder, Sarah A; Long, Charlotte; Moore, Chris W; Satterthwaite, Danielle; Davies, Helena; Allainguillaume, Joel; Ronca, Sandra; Tatarinova, Tatiana; Garbett, Hannah; Walker, Kevin; Wilkinson, Mike J

    2012-01-01

    We present the first national DNA barcode resource that covers the native flowering plants and conifers for the nation of Wales (1143 species). Using the plant DNA barcode markers rbcL and matK, we have assembled 97.7% coverage for rbcL, 90.2% for matK, and a dual-locus barcode for 89.7% of the native Welsh flora. We have sampled multiple individuals for each species, resulting in 3304 rbcL and 2419 matK sequences. The majority of our samples (85%) are from DNA extracted from herbarium specimens. Recoverability of DNA barcodes is lower using herbarium specimens, compared to freshly collected material, mostly due to lower amplification success, but this is balanced by the increased efficiency of sampling species that have already been collected, identified, and verified by taxonomic experts. The effectiveness of the DNA barcodes for identification (level of discrimination) is assessed using four approaches: the presence of a barcode gap (using pairwise and multiple alignments), formation of monophyletic groups using Neighbour-Joining trees, and sequence similarity in BLASTn searches. These approaches yield similar results, providing relative discrimination levels of 69.4 to 74.9% of all species and 98.6 to 99.8% of genera using both markers. Species discrimination can be further improved using spatially explicit sampling. Mean species discrimination using barcode gap analysis (with a multiple alignment) is 81.6% within 10×10 km squares and 93.3% for 2×2 km squares. Our database of DNA barcodes for Welsh native flowering plants and conifers represents the most complete coverage of any national flora, and offers a valuable platform for a wide range of applications that require accurate species identification.

  2. Predicting establishment of non-native fishes in Greece: identifying key features

    Directory of Open Access Journals (Sweden)

    Christos Gkenas

    2015-11-01

    Full Text Available Non-native fishes are known to cause economic damage to human society and are considered a major threat to biodiversity loss in freshwater ecosystems. The growing concern about these impacts has driven to an investigation of the biological traits that facilitate the establishment of non-native fish. However, invalid assessment in choosing the appropriate statistical model can lead researchers to ambiguous conclusions. Here, we present a comprehensive comparison of traditional and alternative statistical methods for predicting fish invasions using logistic regression, classification trees, multicorrespondence analysis and random forest analysis to determine characteristics of successful and failed non-native fishes in Hellenic Peninsula through establishment. We defined fifteen categorical predictor variables with biological relevance and measures of human interest. Our study showed that accuracy differed according to the model and the number of factors considered. Among all the models tested, random forest and logistic regression performed best, although all approaches predicted non-native fish establishment with moderate to excellent results. Detailed evaluation among the models corresponded with differences in variables importance, with three biological variables (parental care, distance from nearest native source and maximum size and two variables of human interest (prior invasion success and propagule pressure being important in predicting establishment. The analyzed statistical methods presented have a high predictive power and can be used as a risk assessment tool to prevent future freshwater fish invasions in this region with an imperiled fish fauna.

  3. Word Durations in Non-Native English

    Science.gov (United States)

    Baker, Rachel E.; Baese-Berk, Melissa; Bonnasse-Gahot, Laurent; Kim, Midam; Van Engen, Kristin J.; Bradlow, Ann R.

    2010-01-01

    In this study, we compare the effects of English lexical features on word duration for native and non-native English speakers and for non-native speakers with different L1s and a range of L2 experience. We also examine whether non-native word durations lead to judgments of a stronger foreign accent. We measured word durations in English paragraphs read by 12 American English (AE), 20 Korean, and 20 Chinese speakers. We also had AE listeners rate the `accentedness' of these non-native speakers. AE speech had shorter durations, greater within-speaker word duration variance, greater reduction of function words, and less between-speaker variance than non-native speech. However, both AE and non-native speakers showed sensitivity to lexical predictability by reducing second mentions and high frequency words. Non-native speakers with more native-like word durations, greater within-speaker word duration variance, and greater function word reduction were perceived as less accented. Overall, these findings identify word duration as an important and complex feature of foreign-accented English. PMID:21516172

  4. Complementary resource use by tree species in a rain forest tree plantation.

    Science.gov (United States)

    Richards, Anna E; Schmidt, Susanne

    2010-07-01

    Mixed-species tree plantations, composed of high-value native rain forest timbers, are potential forestry systems for the subtropics and tropics that can provide ecological and production benefits. Choices of rain forest tree species for mixtures are generally based on the concept that assemblages of fast-growing and light-demanding species are less productive than assemblages of species with different shade tolerances. We examined the hypothesis that mixtures of two fast-growing species compete for resources, while mixtures of shade-tolerant and shade-intolerant species are complementary. Ecophysiological characteristics of young trees were determined and analyzed with a physiology-based canopy model (MAESTRA) to test species interactions. Contrary to predictions, there was evidence for complementary interactions between two fast-growing species with respect to nutrient uptake, nutrient use efficiency, and nutrient cycling. Fast-growing Elaeocarpus angustifolius had maximum demand for soil nutrients in summer, the most efficient internal recycling of N, and low P use efficiency at the leaf and whole-plant level and produced a large amount of nutrient-rich litter. In contrast, fast-growing Grevillea robusta had maximum demand for soil nutrients in spring and highest leaf nutrient use efficiency for N and P and produced low-nutrient litter. Thus, mixtures of fast-growing G. robusta and E. angustifolius or G. robusta and slow-growing, shade-tolerant Castanospermum australe may have similar or even greater productivity than monocultures, as light requirement is just one of several factors affecting performance of mixed-species plantations. We conclude that the knowledge gained here will be useful for designing large-scale experimental mixtures and commercial forestry systems in subtropical Australia and elsewhere.

  5. Genetic Diversity and Population Structure in Native Chicken Populations from Myanmar, Thailand and Laos by Using 102 Indels Markers

    Directory of Open Access Journals (Sweden)

    A. A. Maw

    2015-01-01

    Full Text Available The genetic diversity of native chicken populations from Myanmar, Thailand, and Laos was examined by using 102 insertion and/or deletion (indels markers. Most of the indels loci were polymorphic (71% to 96%, and the genetic variability was similar in all populations. The average observed heterozygosities (HO and expected heterozygosities (HE ranged from 0.205 to 0.263 and 0.239 to 0.381, respectively. The coefficients of genetic differentiation (Gst for all cumulated populations was 0.125, and the Thai native chickens showed higher Gst (0.088 than Myanmar (0.041 and Laotian (0.024 populations. The pairwise Fst distances ranged from 0.144 to 0.308 among populations. A neighbor-joining (NJ tree, using Nei’s genetic distance, revealed that Thai and Laotian native chicken populations were genetically close, while Myanmar native chickens were distant from the others. The native chickens from these three countries were thought to be descended from three different origins (K = 3 from STRUCTURE analysis. Genetic admixture was observed in Thai and Laotian native chickens, while admixture was absent in Myanmar native chickens.

  6. Sleep and native language interference affect non-native speech sound learning.

    Science.gov (United States)

    Earle, F Sayako; Myers, Emily B

    2015-12-01

    Adults learning a new language are faced with a significant challenge: non-native speech sounds that are perceptually similar to sounds in one's native language can be very difficult to acquire. Sleep and native language interference, 2 factors that may help to explain this difficulty in acquisition, are addressed in 3 studies. Results of Experiment 1 showed that participants trained on a non-native contrast at night improved in discrimination 24 hr after training, while those trained in the morning showed no such improvement. Experiments 2 and 3 addressed the possibility that incidental exposure to perceptually similar native language speech sounds during the day interfered with maintenance in the morning group. Taken together, results show that the ultimate success of non-native speech sound learning depends not only on the similarity of learned sounds to the native language repertoire, but also to interference from native language sounds before sleep.

  7. Contrasting xylem vessel constraints on hydraulic conductivity between native and non-native woody understory species

    Directory of Open Access Journals (Sweden)

    Maria S Smith

    2013-11-01

    Full Text Available We examined the hydraulic properties of 82 native and non-native woody species common to forests of Eastern North America, including several congeneric groups, representing a range of anatomical wood types. We observed smaller conduit diameters with greater frequency in non-native species, corresponding to lower calculated potential vulnerability to cavitation index. Non-native species exhibited higher vessel-grouping in metaxylem compared with native species, however, solitary vessels were more prevalent in secondary xylem. Higher frequency of solitary vessels in secondary xylem was related to a lower potential vulnerability index. We found no relationship between anatomical characteristics of xylem, origin of species and hydraulic conductivity, indicating that non-native species did not exhibit advantageous hydraulic efficiency over native species. Our results confer anatomical advantages for non-native species under the potential for cavitation due to freezing, perhaps permitting extended growing seasons.

  8. Acclimation of Pistacia integerrima trees to frost in semi-arid environments depends on autumn's drought.

    Science.gov (United States)

    Sperling, Or; Secchi, Francesca; Godfrey, Jessie; Zwieniecki, Maciej A

    2017-03-01

    Main conclusion Cold acclimation is revealed through induced stem respiration during pre-winter frost of native Pistacia integerrima trees in continental semi-arid environments. Semi-arid environments challenge vegetation by simultaneous abiotic stresses. In this study, we examine the combined effects of water stress and frost on the physiology of Pistacia integerrima stems. This species is native to semi-arid environments where drought and frost frequently co-occur. We quantified carbohydrates and proline in P. integerrima stems responding to frost and experiencing water potentials between -0.2 and -1.8 MPa. We report that dehydrated trees (i.e., Ψstem <=-1 MPa) had more soluble sugars and proline than the well-watered trees (-0.2 MPa). The dehydrated trees also froze at lower temperatures and were less damaged by freezing. Interestingly, we observed a significant increase in stem CO2 efflux at near-freezing temperatures that could be linked to frost protection. This novel finding challenges current paradigm of plant respiration-kinetics which predicts, according to Arrhenius equation, lower respiration rates during frost. Our results support the notion that drought and frost are analogous stresses that can independently activate corresponding physiological processes in trees and amplify protection. This inevitable stress response 'collaboration' may be the key to understanding how non-dormant perennial plants survive the highly variable weather patterns of early winters in semi-arid environments.

  9. Disentangling the effects of shrubs and herbivores on tree regeneration in a dry Chaco forest (Argentina).

    Science.gov (United States)

    Tálamo, Andrés; Barchuk, Alicia H; Garibaldi, Lucas A; Trucco, Carlos E; Cardozo, Silvana; Mohr, Federico

    2015-07-01

    Successful persistence of dry forests depends on tree regeneration, which depends on a balance of complex biotic interactions. In particular, the relative importance and interactive effects of shrubs and herbivores on tree regeneration are unclear. In a manipulative study, we investigated if thornless shrubs have a direct net effect, an indirect positive effect mediated by livestock, and/or an indirect negative effect mediated by small vertebrates on tree regeneration of two key species of Chaco forest (Argentina). In a spatial association study, we also explored the existence of net positive interactions from thorny and thornless shrubs. The number of Schinopsis lorentzii seedlings was highest under artificial shade with native herbivores and livestock excluded. Even excluding livestock, no seedlings were found with natural conditions (native herbivores present with natural shade or direct sunlight) at the end of the experiment. Surprisingly, seedling recruitment was not enhanced under thornless shrubs, because there was a complementary positive effect of shade and interference. Moreover, thornless shrubs had neither positive nor negative effects on regeneration of S. lorentzii. Regeneration of Aspidosperma quebracho-blanco was minimal in all treatments. In agreement with the experiment, spatial distributions of saplings of both tree species were independent of thornless shrubs, but positively associated with thorny shrubs. Our results suggest that in general thornless shrubs may have a negligible effect and thorny shrubs a net positive effect on tree regeneration in dry forests. These findings provide a conceptual framework for testing the impact of biotic interactions on seedling recruitment in other dry forests.

  10. Challenging the Concept of Natural Distributions: Global Change Turns Trees Into Weeds

    Science.gov (United States)

    Gleadow, R.; O'Leary, B.; Burd, M.

    2015-12-01

    National parks and nature reserves are set aside to preserve certain ecosystems, reflecting species distributions at a moment in time. Changing climate and fire dynamics can mean that the species most suited to that area are different, leading new tree species to 'invade' the conservation areas. Pittosporum undulatum is an invasive tree native tree species with a natural range from southeast Queensland to Eastern Victoria, Australia. Soon after European settlement this species became a popular ornamental tree in gardens and was planted outside of its natural range across the continent and introduced to the USA (where it is known as Victorian Box), the Hawaiian Islands, Jamaica, southern Africa and the Azores. The reason this is important is because high density of P. undulatum lead to reduced biodiversity and often the complete suppression of regeneration of exiting forest trees. In Australia, changes in fire dynamics have played a major part in its in dominance. New strategies for forest management were proposed by Gleadow an Ashton in the 1980s, but lack of action has led us to predict that the entire Dandenong Ranges, near Melbourne, will be invaded within 25 years resulting in the loss of a major recreational and conservation area. This is a model of the type of problems that can be expected as the climate envelope for species changes in the coming century, challenging the very concept of a "native ".

  11. Aerococcus viridans Native Valve Endocarditis

    Directory of Open Access Journals (Sweden)

    Wenwan Zhou

    2013-01-01

    Full Text Available Aerococcus viridans is an infrequent human pathogen and few cases of infective endocarditis have been reported. A case involving a 69-year-old man with colon cancer and hemicolectomy 14 years previously, without recurrence, is reported. A diagnosis of native mitral valve endocarditis was established on the basis of clinical presentation, characteristic echocardiographic findings and pathological specimen examination after urgent valve replacement. A viridans endocarditis appears to be particularly virulent, requiring a surgical approach in four of 10 cases reported and death in one of nine. Given the aggressive nature of A viridans endocarditis and the variable time to diagnosis (a few days to seven months, prompt recognition of symptoms and echocardiography, in addition to blood cultures, should be performed when symptoms persist.

  12. Speaking C++ as a native

    Science.gov (United States)

    Stroustrup, Bjarne

    2001-08-01

    C++ supports several styles ("multiple paradigms") of programming. This allows great flexibility, notational convenience, maintainability, and close-to-optimal performance. Programmers who don't know the basic native C++ styles and techniques "speak" C++ with a thick accent, limiting themselves to relatively restrictive pidgin dialects. Here, I present language features such as classes, class hierarchies, abstract classes, and templates, together with the fundamental programming styles they support. In particular, I show how to provide generic algorithms, function objects, access objects, and delayed evaluation as needed to build and use flexible and efficient libraries. The aim is to give an idea of what's possible to provide, and some understanding of the fundamental techniques of modern C++ libraries.

  13. Discovery of highly conserved unique peanut and tree nut peptides by LC-MS/MS for multi-allergen detection.

    Science.gov (United States)

    Sealey-Voyksner, Jennifer; Zweigenbaum, Jerry; Voyksner, Robert

    2016-03-01

    Proteins unique to peanuts and various tree nuts have been extracted, subjected to trypsin digestion and analysis by liquid chromatography/quadrupole time-of-flight mass spectrometry, in order to find highly conserved peptides that can be used as markers to detect peanuts and tree nuts in food. The marker peptide sequences chosen were those found to be present in both native (unroasted) and thermally processed (roasted) forms of peanuts and tree nuts. Each peptide was selected by assuring its presence in food that was processed or unprocessed, its abundance for sensitivity, sequence size, and uniqueness for peanut and each specific variety of tree nut. At least two peptides were selected to represent peanut, almond, pecan, cashew, walnut, hazelnut, pine nut, Brazil nut, macadamia nut, pistachio nut, chestnut and coconut; to determine the presence of trace levels of peanut and tree nuts in food by a novel multiplexed LC-MS method.

  14. Effects of the emerald ash borer invasion on the community composition of arthropods associated with ash tree boles

    Science.gov (United States)

    Emerald ash borer (EAB), Agrilus planipennis Fairmaire is an invasive non-native wood-boring beetle that has killed hundreds of millions of ash trees (Fraxinus spp.) in North America, and threatens to extirpate the ecological services provided by the genus. Identifying the arthropod community assoc...

  15. Genetic diversity and population structure in wild stands of cacao trees (Theobroma cacao L.) in French Guiana

    Science.gov (United States)

    Background and Aims The native cacao trees (Theobroma cacao L.) in French Guiana represent an important fraction of genetic diversity of this species. Several scientific surveys have led to the collection of germplasm accessions from south-eastern French Guiana, which provides an ideal opportunit...

  16. Temporal dynamics of arthropods on six tree species in dry woodlands on the Caribbean Island of Puerto Rico

    Science.gov (United States)

    W. Beltran; Joseph Wunderle Jr.

    2014-01-01

    The seasonal dynamics of foliage arthropod populations are poorly studied in tropical dry forests despite the importance of these studies for understanding arthropod population responses to environmental change.We monitored the abundance, temporal distributions, and body size of arthropods in five naturalized alien and one native tree species to characterize arthropod...

  17. Turkish Students' Perspectives on Speaking Anxiety in Native and Non-Native English Speaker Classes

    Science.gov (United States)

    Bozavli, Ebubekir; Gulmez, Recep

    2012-01-01

    The aim of this study is to reveal the effect of FLA (foreign language anxiety) in native/non-native speaker of English classrooms. In this study, two groups of students (90 in total) of whom 38 were in NS (native speaker) class and 52 in NNS (non-native speaker) class taking English as a second language course for 22 hours a week at Erzincan…

  18. Threatened pollination systems in native flora of the Ogasawara (Bonin) Islands.

    Science.gov (United States)

    Abe, Tetsuto

    2006-08-01

    Various alien species have been introduced to the Ogasawara Islands (Japan). A survey was made investigating whether the native pollination systems fit an 'island syndrome' (biasing the flora to dioecy, with subdued, inconspicuous flowers) and whether alien species have disrupted the native pollination network. Flower visitors and floral traits were determined in the field (12 islands) and from the literature. Associations among floral traits such as sexual expression, flower colour and flower shape were tested. Among the 269 native flowering plants, 74.7 % are hermaphroditic, 13.0 % are dioecious and 7.1 % are monoecious. Classification by flower colour revealed that 36.0 % were white, 21.6 % green and 13.8 % yellow. Woody species (trees and shrubs) comprised 36.5 % of the flora and were associated with dioecy and white flowers. Solitary, endemic small bees were the dominant flower visitors and visited 66.7 % of the observed species on satellite islands where the native pollination networks are preserved. In contrast to the situation on the satellite islands, introduced honeybees were the most dominant pollinator (visiting 60.1 % of observed species) on the two main islands, Chichi-jima and Haha-jima, and had spread to satellite islands near Chichi-jima Island. The island syndrome for pollination systems in the Ogasawara Islands was evident in a high percentage of dioecious species, the subdued colour of the native flora and solitary flower visitors on satellite islands. The shape and colour adaptations of several flowers suggested native pollination niches for long-proboscis moths and carpenter bees. However, the domination and expansion of introduced honeybees have the potential for disruption of the native pollination network in the two main, and several satellite, islands of the Ogasawara Islands.

  19. Firewood yields of individual trees of Guazuma Ulmifolia Lam. In Pastures in Hojancha Guanacaste - Costa Rica

    Energy Technology Data Exchange (ETDEWEB)

    Salazar, R.; Rose, D.

    1984-12-01

    Guazuma ulmifolia Lam. (guacimo), because of its wide distribution, easy handling, and high firewood quality, is a promising native species for firewood production in the wet and dry regions of Central America. It is possible to make an accurate estimate of the firewood weight of the crown of a guacimo tree that has been periodically harvested, using regression models based on basal diameter of the branches and diameter at breast height crown diameter and age. Several firewood weight tables were developed which can be used to make estimates for periodically harvested individual trees growing in pastures.

  20. Delayed tree mortality in the Atchafalaya Basin of Southern Louisiana following Hurricane Andrew

    Science.gov (United States)

    Keeland, B.D.; Gorham, L.E.

    2009-01-01

    Hurricanes can damage trees in forested wetlands, and the potential for mortality related to these storms exists due to the effects of tree damage over time. In August 1992, Hurricane Andrew passed through the forested wetlands of southern Louisiana with winds in excess of 225 kph. Although more than 78 of the basal area was destroyed in some areas, most trees greater than 2.5 cm dbh were alive and resprouting prolifically the following year (98.8). Survival of most tree species was similarly high two years after the hurricane, but mortality rates of some species increased dramatically. For example, Populus heterophylla (swamp cottonwood) mortality increased from 7.8 to 59.2 (n 76) and Salix interior (sandbar willow) mortality increased from 4.5 to 57.1 (n 21). Stem sprouts on many up-rooted hardwood trees of other species were still alive in 1998, 6 years after the hurricane. Due to the understory tree species composition, regeneration, and high levels of resprouting, there was little change in species composition or perhaps a slight shift toward more shade and flood tolerant species six years following the hurricane event. Triadica sebifera (Chinese tallow) was found on some of the sites heavily disturbed by Hurricane Andrew, and may proliferate at the expense of native tree species. ?? 2009 The Society of Wetland Scientists.

  1. Influence of native and non-native multitalker babble on speech recognition in noise

    Directory of Open Access Journals (Sweden)

    Chandni Jain

    2014-03-01

    Full Text Available The aim of the study was to assess speech recognition in noise using multitalker babble of native and non-native language at two different signal to noise ratios. The speech recognition in noise was assessed on 60 participants (18 to 30 years with normal hearing sensitivity, having Malayalam and Kannada as their native language. For this purpose, 6 and 10 multitalker babble were generated in Kannada and Malayalam language. Speech recognition was assessed for native listeners of both the languages in the presence of native and nonnative multitalker babble. Results showed that the speech recognition in noise was significantly higher for 0 dB signal to noise ratio (SNR compared to -3 dB SNR for both the languages. Performance of Kannada Listeners was significantly higher in the presence of native (Kannada babble compared to non-native babble (Malayalam. However, this was not same with the Malayalam listeners wherein they performed equally well with native (Malayalam as well as non-native babble (Kannada. The results of the present study highlight the importance of using native multitalker babble for Kannada listeners in lieu of non-native babble and, considering the importance of each SNR for estimating speech recognition in noise scores. Further research is needed to assess speech recognition in Malayalam listeners in the presence of other non-native backgrounds of various types.

  2. Comparison of native and non-native phone imitation by English and Spanish speakers.

    Science.gov (United States)

    Olmstead, Anne J; Viswanathan, Navin; Aivar, M Pilar; Manuel, Sarath

    2013-01-01

    Experiments investigating phonetic convergence in conversation often focus on interlocutors with similar phonetic inventories. Extending these experiments to those with dissimilar inventories requires understanding the capacity of speakers to imitate native and non-native phones. In the present study, we tested native Spanish and native English speakers to determine whether imitation of non-native tokens differs qualitatively from imitation of native tokens. Participants imitated a [ba]-[pa] continuum that varied in VOT from -60 ms (prevoiced, Spanish [b]) to +60 ms (long lag, English [p]) such that the continuum consisted of some tokens that were native to Spanish speakers and some that were native to English speakers. Analysis of the imitations showed two critical results. First, both groups of speakers demonstrated sensitivity to VOT differences in tokens that fell within their native regions of the VOT continuum (prevoiced region for Spanish and long lag region for English). Secondly, neither group of speakers demonstrated such sensitivity to VOT differences among tokens that fell in their non-native regions of the continuum. These results show that, even in an intentional imitation task, speakers cannot accurately imitate non-native tokens, but are clearly flexible in producing native tokens. Implications of these findings are discussed with reference to the constraints on convergence in interlocutors from different linguistic backgrounds.

  3. Vowel perception: Effects of non-native language versus non-native dialect

    NARCIS (Netherlands)

    Cutler, A.; Smits, R.; Cooper, N.

    2005-01-01

    Three groups of listeners identified the vowel in CV and VC syllables produced by an American English talker. The listeners were (a) native speakers of American English, (b) native speakers of Australian English (different dialect), and (c) native speakers of Dutch (different language). The syllable

  4. Native- and Non-Native Speaking English Teachers in Vietnam: Weighing the Benefits

    Science.gov (United States)

    Walkinshaw, Ian; Duong, Oanh Thi Hoang

    2012-01-01

    This paper examines a common belief that learners of English as a foreign language prefer to learn English from native-speaker teachers rather than non-native speakers of English. 50 Vietnamese learners of English evaluated the importance of native-speakerness compared with seven qualities valued in an English language teacher: teaching…

  5. Risk to native Uroleucon aphids (Hemiptera: Aphididae) from non-native lady beetles (Coleoptera: Coccinellidae)

    Science.gov (United States)

    Aphids in the genus Uroleucon Mordvilko (Hemiptera: Aphididae) are native herbivores that feed on goldenrod (Solidago spp.) and other Asteraceae in North America. The aphids are potential prey for a wide variety of natural enemies, including native and non-native species of lady beetles (Coleoptera...

  6. Native American History in a Box: A New Approach to Teaching Native American Cultures

    Science.gov (United States)

    Helms, Emory C.; Hitt, Austin M.; Schipper, Jason A.; Jones, Adam M.

    2010-01-01

    This article describes the Native American History in a Box curriculum which is designed to introduce elementary and middle-level students to Native American cultures. The curriculum consists of a five day unit addressing the following concepts pertaining to Native American Nations: settlements, tools, sustenance, pottery, and contact with…

  7. Vowel perception: Effects of non-native language versus non-native dialect

    NARCIS (Netherlands)

    Cutler, A.; Smits, R.; Cooper, N.

    2005-01-01

    Three groups of listeners identified the vowel in CV and VC syllables produced by an American English talker. The listeners were (a) native speakers of American English, (b) native speakers of Australian English (different dialect), and (c) native speakers of Dutch (different language). The

  8. Comparison of native and non-native phone imitation by English and Spanish speakers

    Directory of Open Access Journals (Sweden)

    Annie J Olmstead

    2013-07-01

    Full Text Available Experiments investigating phonetic convergence in conversation often focus on interlocutors with similar phonetic inventories. Extending these experiments to those with dissimilar inventories requires understanding the capacity of speakers to imitate native and non-native phones. In the present study, we tested native Spanish and native English speakers to determine whether imitation of non-native tokens differs qualitatively from imitation of native tokens. Participants imitated a [ba] -[pa] continuum that varied in VOT from -60 ms (prevoiced, Spanish [b] to +60 ms (long lag, English [p] such that the continuum consisted of some tokens that were native to Spanish speakers and some that were native to English speakers. Analysis of the imitations showed two critical results. First, both groups of speakers demonstrated sensitivity to VOT differences in tokens that fell within their native regions of the VOT continuum (prevoiced region for Spanish and long lag region for English. Secondly, neither group of speakers demonstrated such sensitivity to VOT differences among tokens that fell in their non-native regions of the continuum. These results show that, even in an intentional imitation task, speakers cannot accurately imitate non-native tokens, but are clearly flexible in producing native tokens. Implications of these findings are discussed with reference to the constraints on convergence in interlocutors from different linguistic backgrounds.

  9. Linking dominant Hawaiian tree species to understory development in recovering pastures via impacts on soils and litter

    Science.gov (United States)

    Yelenik, Stephanie G.

    2017-01-01

    Large areas of tropical forest have been cleared and planted with exotic grass species for use as cattle pasture. These often remain persistent grasslands after grazer removal, which is problematic for restoring native forest communities. It is often hoped that remnant and/or planted trees can jump-start forest succession; however, there is little mechanistic information on how different canopy species affect community trajectories. To investigate this, I surveyed understory communities, exotic grass biomass, standing litter pools, and soil properties under two dominant canopy trees—Metrosideros polymorpha (‘ōhi‘a) and Acacia koa (koa)—in recovering Hawaiian forests. I then used structural equation models (SEMs) to elucidate direct and indirect effects of trees on native understory. Native understory communities developed under ‘ōhi‘a, which had larger standing litter pools, lower soil nitrogen, and lower exotic grass biomass than koa. This pattern was variable, potentially due to historical site differences and/or distance to intact forest. Koa, in contrast, showed little understory development. Instead, data suggest that increased soil nitrogen under koa leads to high grass biomass that stalls native recruitment. SEMs suggested that indirect effects of trees via litter and soils were as or more important than direct effects for determining native cover. It is suggested that diverse plantings which incorporate species that have high carbon to nitrogen ratios may help ameliorate the negative indirect effects of koa on natural understory regeneration.

  10. A latitudinal cline in disease resistance of a host tree.

    Science.gov (United States)

    Hamilton, M G; Williams, D R; Tilyard, P A; Pinkard, E A; Wardlaw, T J; Glen, M; Vaillancourt, R E; Potts, B M

    2013-04-01

    The possible drivers and implications of an observed latitudinal cline in disease resistance of a host tree were examined. Mycosphaerella leaf disease (MLD) damage, caused by Teratosphaeria species, was assessed in five Eucalyptus globulus (Tasmanian blue gum) common garden trials containing open-pollinated progeny from 13 native-forest populations. Significant population and family within population variation in MLD resistance was detected, which was relatively stable across different combinations of trial sites, ages, seasons and epidemics. A distinct genetic-based latitudinal cline in MLD damage among host populations was evident. Two lines of evidence argue that the observed genetic-based latitudinal trend was the result of direct pathogen-imposed selection for MLD resistance. First, MLD damage was positively associated with temperature and negatively associated with a prediction of disease risk in the native environment of these populations; and, second, the quantitative inbreeding coefficient (QST) significantly exceeded neutral marker FST at the trial that exhibited the greatest MLD damage, suggesting that diversifying selection contributed to differentiation in MLD resistance among populations. This study highlights the potential for spatial variation in pathogen risk to drive adaptive differentiation across the geographic range of a foundation host tree species.

  11. The role of exotic tree species in Nordic forestry

    DEFF Research Database (Denmark)

    Kjær, Erik Dahl; Lobo, Albin; Myking, Tor

    2014-01-01

    The selection of suitable tree species is a prerequisite for successful forestry, and the use of exotic species as an alternative to native species is often a relevant option. In this paper, we discuss this option in relation to the present and future wood production in Nordic forestry. We revisi...... the expected climate changes, we discuss whether and how the increased use of exotic species can contribute to sustained and increased health and productivity of Nordic forests without jeopardising ecological and social values.......The selection of suitable tree species is a prerequisite for successful forestry, and the use of exotic species as an alternative to native species is often a relevant option. In this paper, we discuss this option in relation to the present and future wood production in Nordic forestry. We revisit...... the vegetation and forest history and its implications for the interest in using exotic species. We review to what extent exotic species can contribute to increased economic returns from forest plantings and the potential negative ecological effects associated with introduction of new species. Considering...

  12. Some Results on Metric Trees

    CERN Document Server

    Aksoy, Asuman Guven

    2010-01-01

    Using isometric embedding of metric trees into Banach spaces, this paper will investigate barycenters, type and cotype, and various measures of compactness of metric trees. A metric tree ($T$, $d$) is a metric space such that between any two of its points there is an unique arc that is isometric to an interval in $\\mathbb{R}$. We begin our investigation by examining isometric embeddings of metric trees into Banach spaces. We then investigate the possible images $x_0=\\pi ((x_1+\\ldots+x_n)/n)$, where $\\pi$ is a contractive retraction from the ambient Banach space $X$ onto $T$ (such a $\\pi$ always exists) in order to understand the "metric" barycenter of a family of points $ x_1, \\ldots,x_n$ in a tree $T$. Further, we consider the metric properties of trees such as their type and cotype. We identify various measures of compactness of metric trees (their covering numbers, $\\epsilon$-entropy and Kolmogorov widths) and the connections between them. Additionally, we prove that the limit of the sequence of Kolmogorov...

  13. Widespread dieback of riparian trees on a dammed ephemeral river and evidence of local mitigation by tributary flows

    Directory of Open Access Journals (Sweden)

    Caitlin M. S. Douglas

    2016-10-01

    Full Text Available Ephemeral rivers act as linear oases in drylands providing key resources to people and wildlife. However, not much is known about these rivers’ sensitivities to human activities. We investigated the landscape-level determinants of riparian tree dieback along the Swakop River, a dammed ephemeral river in Namibia, focusing on the native ana tree (Faidherbia albida and the invasive mesquite (Prosopis spp.. We surveyed over 1,900 individual trees distributed across 24 sites along a 250 km stretch of the river. General linear mixed models were used to test five hypotheses relating to three anthropogenic threats: river flow disruption from damming, human settlement and invasive species. We found widespread dieback in both tree populations: 51% mortality in ana tree, with surviving trees exhibiting 18% canopy death (median; and 26% mortality in mesquite, with surviving trees exhibiting 10% canopy death. Dieback in the ana tree was most severe where trees grew on drier stretches of the river, where tributary flow was absent and where mesquite grew more abundantly. Dieback in the mesquite, a more drought-tolerant taxon, did not show any such patterns. Our findings suggest that dieback in the ana tree is primarily driven by changes in river flow resulting from upstream dam creation and that tributary flows provide a local buffer against this loss of main channel flow. The hypothesis that the invasive mesquite may contribute to ana tree dieback was also supported. Our findings suggest that large dams along the main channels of ephemeral rivers have the ability to cause widespread mortality in downstream riparian trees. To mitigate such impacts, management might focus on the maintenance of natural tributary flows to buffer local tree populations from the disruption to main channel flow.

  14. What Good Is a Tree?

    Institute of Scientific and Technical Information of China (English)

    Lowell; Ponte; 史书碧

    1998-01-01

    文章开头说:Trees are so common and quiet that we pay them little mind. 其实,初见此标题——What Good Is a Tree?笔者也pay this essay little mind。这个题目还能够讲出多少新意来呢?不料,细读之后,竟不忍释手! Trees sustain our lives and our planet in a thousand practical ways. Trees do more than make life pleasant;they make life possible. 这是文章的两句主题句。读罢全文,认真一想,便觉这决非耸人听闻之言:无言的树,“挪死”的树,支撑着我们这个星球,庇护着天下的生灵!诸如: …they draw carbon dioxide from the air…and oxygen iS released. Without tree our entire world would be a much drier place. For centuries,the Chinese have derived medicines form the ginkgo tree. 让读者双眼一亮的是,文章提供了许多你我都不曾想到的有关树的信息: a.树木能彼此互通信息: …trees send unseen signals to each other.When willows are attacked bywebworms and tent caterpillars,they give off a chemical that alerts nearby trees.Theneighboring trees respond by pumping more tannin into their leaves,making them moredifficult for the insects tO digest。 更让人?

  15. Reading Native American Literature: A Teacher's Guide

    Science.gov (United States)

    Goebel, Bruce A.

    2004-01-01

    High school and college teachers interested in offering units or courses on Native American literature have often had to carve out new teaching strategies because ready resources and guides are scarce. In "Reading Native American Literature: A Teacher's Guide," Bruce A. Goebel offers innovative and practical suggestions about how to introduce…

  16. Support for Native Americans with Developmental Disabilities.

    Science.gov (United States)

    Goodman, Wylie; Rife, Christine

    This report addresses the high incidence of fetal alcohol syndrome (FAS) and fetal alcohol effects (FAE) among Native Americans and suggests that there is a lack of comprehensive effort to provide outreach services to the Native American population in Illinois. The report begins with an overview of American Indian history and the migration of…

  17. Native grasses for rehabilitating Hunter Valley minesites

    Energy Technology Data Exchange (ETDEWEB)

    Huxtable, C. [NSW Department of Land and Water Conservation, NSW (Australia)

    1998-04-01

    Introduced plant species, particularly grasses, have long been used to rehabilitate mined land in Australia. Interest in using native species spawned a research project in the Hunter Valley which has demonstrated the suitability of certain native species for rehabilitation and put forward guidelines to enhance the chance of their successful establishment. 4 photos., 1 tab.

  18. The Native Speaker: Membership Has Its Privileges.

    Science.gov (United States)

    Siskin, H. Jay

    This paper responds to Claire Kramsch's essay on the demise of the notion of the idealized native speaker as the model for second language learning and implications for second languages and cultures education. In her essay, Kramsch forcefully argues against the native speaker construct and exhorts teachers and learners not to abandon their unique…

  19. Stennis Space Center celebrates Native American culture

    Science.gov (United States)

    2009-01-01

    Famie Willis (left), 2009-2010 Choctaw Indian Princess, displays artifacts during Native American Heritage Month activities at Stennis Space Center on Nov. 24. The celebration featured various Native American cultural displays for Stennis employees to view. Shown above are (l to r): Willis, Elaine Couchman of NASA Shared Services Center, John Cecconi of NSSC and Lakeisha Robertson of the Environmental Protection Agency.

  20. How Digital Native Learners Describe Themselves

    Science.gov (United States)

    Thompson, Penny

    2015-01-01

    Eight university students from the "digital native" generation were interviewed about the connections they saw between technology use and learning, and also their reactions to the popular press claims about their generation. Themes that emerged from the interviews were coded to show patterns in how digital natives describe themselves.…