Nitrogen Fertilization Increases Cottonwood Growth on Old-Field Soil

Science.gov (United States)

B. G. Blackmon; E. H. White

1972-01-01

Nitrogen (150 lb ./acre as NH4N03 ) applied to a 6-year-old eastern cottonwood plantation in an old field on Commerce silt loam soil increased diameter, basal area, and volume growth by 200 percent over untreated controls. The plantation did not respond to 100 pounds P per acre from concentrated superphosphate.

Ecophysiology of riparian cottonwood and willow before, during, and after two years of soil water removal.

Science.gov (United States)

Hultine, K R; Bush, S E; Ehleringer, J R

2010-03-01

Riparian cottonwood/willow forest assemblages are highly valued in the southwestern United States for their wildlife habitat, biodiversity, and watershed protection. Yet these forests are under considerable threat from climate change impacts on water resources and land-use activities to support human enterprise. Stream diversions, groundwater pumping, and extended drought have resulted in the decline of cottonwood/willow forests along many riparian corridors in the Southwest and, in many cases, the replacement of these forests with less desirable invasive shrubs and trees. Nevertheless, ecophysiological responses of cottonwood and willow, along with associated ecohydrological feedbacks of soil water depletion, are not well understood. Ecophysiological processes of mature Fremont cottonwood and coyote willow stands were examined over four consecutive growing seasons (2004-2007) near Salt Lake City, Utah, USA. The tree stands occurred near the inlet of a reservoir that was drained in the spring of 2005 and remained empty until mid-summer of 2006, effectively removing the primary water source for most of two growing seasons. Stem sap flux density (Js) in cottonwood was highly correlated with volumetric soil moisture (theta) in the upper 60 cm and decreased sevenfold as soil moisture dropped from 12% to 7% after the reservoir was drained. Conversely, Js in willow was marginally correlated with 0 and decreased by only 25% during the same period. Opposite patterns emerged during the following growing season: willow had a lower whole-plant conductance (kt) in June and higher leaf carbon isotope ratios (delta13C) than cottonwood in August, whereas k(t) and delta13C were otherwise similar between species. Water relations in both species recovered quickly from soil water depletion, with the exception that sapwood area to stem area (As:Ast) was significantly lower in both species after the 2007 growing season compared to 2004. Results suggest that cottonwood has a greater

Tree mortality in mature riparian forest: Implications for Fremont cottonwood conservation in the American southwest

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Andersen, Douglas

2015-01-01

Mature tree mortality rates are poorly documented in desert riparian woodlands. I monitored deaths and calculated annual survivorship probability (Ps) in 2 groups of large (27–114 cm DBH), old (≥40 years old) Fremont cottonwood (Populus fremontii Wats.) in a stand along the free-flowing Yampa River in semiarid northwestern Colorado. Ps = 0.993 year-1 in a group (n = 126) monitored over 2003–2013, whereas Ps = 0.985 year-1 in a group (n = 179) monitored over the same period plus 3 earlier years (2000–2003) that included drought and a defoliating insect outbreak. Assuming Ps was the same for both groups during the 10-year postdrought period, the data indicate that Ps = 0.958 year-1 during the drought. I found no difference in canopy dieback level between male and female survivors. Mortality was equal among size classes, suggesting Ps is independent of age, but published longevity data imply that either Ps eventually declines with age or, as suggested in this study, periods with high Ps are interrupted by episodes of increased mortality. Stochastic population models featuring episodes of low Ps suggest a potential for an abrupt decline in mature tree numbers where recruitment is low. The modeling results have implications for woodland conservation, especially for relictual stands along regulated desert rivers.

Insect-induced tree mortality of boreal forests in eastern Canada under a changing climate.

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Zhang, Xiongqing; Lei, Yuancai; Ma, Zhihai; Kneeshaw, Dan; Peng, Changhui

2014-06-01

Forest insects are major disturbances that induce tree mortality in eastern coniferous (or fir-spruce) forests in eastern North America. The spruce budworm (SBW) (Choristoneura fumiferana [Clemens]) is the most devastating insect causing tree mortality. However, the relative importance of insect-caused mortality versus tree mortality caused by other agents and how this relationship will change with climate change is not known. Based on permanent sample plots across eastern Canada, we combined a logistic model with a negative model to estimate tree mortality. The results showed that tree mortality increased mainly due to forest insects. The mean difference in annual tree mortality between plots disturbed by insects and those without insect disturbance was 0.0680 per year (P eastern Canada but that tree mortality induced by insect outbreaks will decrease in eastern Canada under warming climate.

Per tree estimates with n-tree distance sampling: an application to increment core data

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Thomas B. Lynch; Robert F. Wittwer

2002-01-01

Per tree estimates using the n trees nearest a point can be obtained by using a ratio of per unit area estimates from n-tree distance sampling. This ratio was used to estimate average age by d.b.h. classes for cottonwood trees (Populus deltoides Bartr. ex Marsh.) on the Cimarron National Grassland. Increment...

Rooting Cuttings of Cottonwood, WilIow, and Sycamore

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Charles B. Briscoe

1963-01-01

Cuttings of cottonwood, willow, and sycamore were collectd monthly through the year and set in nursery beds. Every species yield an appreciable percentage of rooted cuttings every month. The best month was March; the worst month was June. Willow rooted more cuttings than cottonwood or sycamore, and those which rooted grew faster. Cottonwood grew faster than sycamore....

Establishing trees on cut-over peatlands in eastern Canada

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J. Bussières

2008-12-01

Full Text Available Four major tree-planting trials on cut-over peatlands in eastern Canada were surveyed in 2002, in order to evaluate the potential use of trees in rehabilitation following horticultural peat extraction. At one of the sites, an experiment to determine the appropriate fertilisation rate for trees planted on cut-over peatlands was also conducted over several years. Tree performance was assessed by measuring survival, total height and annual growth of red maple (Acer rubrum L., tamarack (Larix laricina (Du Roi Koch., black spruce (Picea mariana (Mill. B.S.P., jack pine (Pinus banksiana Lamb. and hybrid poplar (Populus spp.. Establishment and growth of tamarack and black spruce in cut-over peatlands showed good potential when compared to performance in conventional forestry plantations. Red maple and jack pine gave poor productivity but promising survival, whilst hybrid poplar plantings failed. Adding nutrients was essential for growth but dosages above 122.5 g of 3.4N-8.3P-24.2K per tree gave no further improvement. Therefore, several different tree species can be planted to reclaim cut-over peatlands in eastern Canada, so long as the appropriate species are chosen and nutrients are provided.

Dendrogeochronologic and Anatomic Analysis of Excavated Plains Cottonwoods Determine Overbank Sedimentation Rates and Historical Channel Positions Along the Interior of a Migrating Meander Bend, Powder River, Montana

Science.gov (United States)

Metzger, T. L.; Pizzuto, J. E.; Schook, D. M.; Hasse, T. R.; Affinito, R. A.

2017-12-01

Dendrochronological dating of buried trees precisely determines the germination year and identifies the stratigraphic context of germination for the trees. This recently developed application of dendrochronology provides accurate time-averaged sedimentation rates of overbank deposition along floodplains and can be used to identify burial events. Previous studies have demonstrated that tamarisk (Tamarix ramosissima) and sandbar willow (Salix exigua) develop anatomical changes within the tree rings (increased vessel size and decreased ring widths) on burial, but observations of plains cottonwood (Populus deltoides ssp. monilifera) are lacking. In September 2016 and June 2017, five buried plains cottonwoods were excavated along a single transect of the interior of a meander bend of the Powder River, Montana. Sediment samples were obtained near each tree for 210Pb and 137Cs dating, which will allow for comparison between dendrochronological and isotopic dating methods. The plains cottonwood samples collected exhibit anatomical changes associated with burial events that are observed in other species. All trees germinated at the boundary between thinly bedded fine sand and mud and coarse sand underlain by sand and gravel, indicating plains cottonwoods germinate on top of point bars prior to overbank deposition. The precise germination age and depth provide elevations and minimum age constraints for the point bar deposits and maximum ages for the overlying sediment, helping constrain past channel positions and overbank deposition rates. Germination years of the excavated trees, estimated from cores taken 1.5 m above ground level, range from 2014 to 1862. Accurate establishment years determined by cross-dating the buried section of the tree can add an additional 10 years to the cored age. The sedimentation rate and accumulation thickness varied with tree age. The germination year, total sediment accumulation, and average sedimentation rate at the five sampled trees is

Identifying data gaps and prioritizing restoration strategies for Fremont cottonwood using linked geomorphic and population models

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Harper, E. B.; Stella, J. C.; Fremier, A. K.

2009-12-01

Fremont cottonwood (Populus fremontii) is an important component of semi-arid riparian ecosystems throughout western North America, but its populations are in decline due to flow regulation. Achieving a balance between human resource needs and riparian ecosystem function requires a mechanistic understanding of the multiple geomorphic and biological factors affecting tree recruitment and survival, including the timing and magnitude of river flows, and the concomitant influence on suitable habitat creation and mortality from scour and sedimentation burial. Despite a great deal of empirical research on some components of the system, such as factors affecting cottonwood recruitment, other key components are less studied. Yet understanding the relative influence of the full suite of physical and life-history drivers is critical to modeling whole-population dynamics under changing environmental conditions. We addressed these issues for the Fremont cottonwood population along the Sacramento River, CA using a sensitivity analysis approach to quantify uncertainty in parameters on the outcomes of a patch-based, dynamic population model. Using a broad range of plausible values for 15 model parameters that represent key physical, biological and climatic components of the ecosystem, we ran 1,000 population simulations that consisted of a subset of 14.3 million possible combinations of parameter estimates to predict the frequency of patch colonization and total forest habitat predicted to occur under current hydrologic conditions after 175 years. Results indicate that Fremont cottonwood populations are highly sensitive to the interactions among flow regime, sedimentation rate and the depth of the capillary fringe (Fig. 1). Estimates of long-term floodplain sedimentation rate would substantially improve model accuracy. Spatial variation in sediment texture was also important to the extent that it determines the depth of the capillary fringe, which regulates the availability of

On the irrigation requirements of cottonwood (Populus fremontii and Populus deltoides var. wislizenii) and willow (Salix gooddingii) grown in a desert environment

Science.gov (United States)

Hartwell, S.; Morino, K.; Nagler, P.L.; Glenn, E.P.

2010-01-01

Native tree plots have been established in river irrigation districts in the western U.S. to provide habitat for threatened and endangered birds. Information is needed on the effective irrigation requirements of the target species. Cottonwood (Populus spp.) and willow (Salix gooddingii) trees were grown for seven years in an outdoor plot in a desert environment in Tucson, Arizona. Plants were allowed to achieve a nearly complete canopy cover over the first four years, then were subjected to three daily summer irrigation schedules of 6.20??mm??d-1; 8.26??mm??d-1 and 15.7??mm??d-1. The lowest irrigation rate was sufficient to maintain growth and high leaf area index for cottonwoods over three years, while willows suffered considerable die-back on this rate in years six and seven. These irrigation rates were applied April 15-September 15, but only 0.88??mm??d-1 was applied during the dormant period of the year. Expressed as a fraction of reference crop evapotranspiration (ETo), recommended annual water applications plus precipitation (and including some deep drainage) were 0.83 ETo for cottonwood and 1.01 ETo for willow. Current practices tend to over-irrigate restoration plots, and this study can provide guidelines for more efficient water use. ?? 2010 Elsevier Ltd.

Tree Nonstructural Carbohydrate Reserves Across Eastern US Temperate Forests

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Mantooth, J.; Dietze, M.

2015-12-01

Understanding the roles, importance, and dynamics of tree non-structural carbohydrates (NSCs) is currently an active area of research. The question of how the relationships between NSCs, growth, and mortality can be used to develop more accurate projections of forest dynamics is central to this research. To begin to address this question, we have asked an even more fundamental question: How much are trees allocating carbon to storage, in the form of NSCs, versus new growth? Ecological theory predicts that there should be trade-offs between different plant life history strategies provided that there are the carbon mass-balance constraints to enforce these trade-offs. Current data on tree NSCs lack the spatial and taxonomic extent required to properly address this question. Therefore, we established a network of forest inventory plots at ten sites across the eastern US and measured growth in adult trees using increment cores and repeat measures of diameter at breast height (DBH). Increment cores were also used to measure sapwood NSCs. We hypothesized that across the eastern US, shade tolerant species, e.g. Sugar Maple (Acer saccharum) have the largest NSC reserves and that shade intolerant species have the lowest reserves. We also hypothesized that NSC reserves increase with temperature and precipitation, as with growth, and that within species NSC reserves increase with growth rate. Initial analyses of tree NSCs indicates that trees of intermediate shade tolerance, e.g. Red Oak (Quercus rubra) have the highest concentrations of sapwood NSCs, and among the highest growth rates. Across the entire study region, NSC concentrations are positively correlated with tree size and growth rate. Within species, NSC concentrations are also positively correlated with growth rate. Across functional groups healthy individuals have significantly higher sapwood NSC concentrations than visibly stressed individuals. There are also significantly lower NSC concentrations in sapwood of

Uses of tree saps in northern and eastern parts of Europe

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Ingvar Svanberg

2012-12-01

Full Text Available In this article we review the use of tree saps in northern and eastern Europe. Published accounts by travellers, ethnologists and ethnobotanists were searched for historical and contemporary details. Field observations made by the authors have also been used. The presented data shows that the use of tree sap has occurred in most north and eastern European countries. It can be assumed that tree saps were most used where there were extensive stands of birch or maple trees, as these two genera generally produce the largest amount of sap. The taxa most commonly used have been Betula pendula, B. pubescens, and Acer platanoides, but scattered data on the use of several other taxa are presented. Tree sap was used as a fresh drink, but also as an ingredient in food and beverages. It was also fermented to make light alcoholic products like ale and wine. Other folk uses of tree saps vary from supplementary nutrition in the form of sugar, minerals and vitamins, to cosmetic applications for skin and hair and folk medicinal use. Russia, Ukraine, Belarus, Estonia, Latvia and Lithuania are the only countries where the gathering and use of sap (mainly birch sap has remained an important activity until recently, due to the existence of large birch forests, low population density and the incorporation of sap into the former Soviet economic system. It is evident that gathering sap from birch and other trees was more widespread in earlier times. There are records indicating extensive use of tree saps from Scandinavia, Poland, Slovakia and Romania, but it is primarily of a historical character. The extraction of tree sap in these countries is nowadays viewed as a curiosity carried out only by a few individuals. However, tree saps have been regaining popularity in urban settings through niche trading.

Predicting abundance of 80 tree species following climate change in the Eastern United States

Science.gov (United States)

Louis R. Iverson; Anantha M. Prasad; Anantha M. Prasad

1998-01-01

Projected climate warming will potentially have profound effects on the earth?s biota, including a large redistribution of tree species. We developed models to evaluate potential shifts for 80 individual tree species in the eastern United States. First, environmental factors associated with current ranges of tree species were assessed using geographic information...

Use of trees by the Texas ratsnake (Elaphe obsoleta) in eastern Texas

Science.gov (United States)

Josh B. Pierce; Robert R. Fleet; Lance McBrayer; D. Craig Rudolph

2008-01-01

We present information on the use of trees by Elaphe obsoleta (Texas Ratsnake) in a mesic pine-hardwood forest in eastern Texas. Using radiotelemetry, seven snakes (3 females, 4 males) were relocated a total of 363 times from April 2004 to May 2005, resulting in 201 unique locations. Snakes selected trees containing cavities and used hardwoods and...

Tree species diversity in the Eastern Ghats of northern Andhra Pradesh, India

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M. Tarakeswara Naidu

2015-06-01

Full Text Available The present study was conducted to analyze tree species diversity in the tropical forests of the Eastern Ghats of northern Andhra Pradesh, India.  A total of 270 species of trees (≥15cm girth at breast height pertaining to 177 genera belonging to 55 families were recorded.  Among the 270 species, 141 species were observed to be common, 78 were occasional and 51 species were rare in the study area.  Fabaceae was the dominant family with 33 species followed by Rubiaceae with 15 species and Malvaceae, Moraceae and Phyllanthaceae with 13 species each.  The genera with the highest number of species include Ficus (12 species, Diospyros (8 species, Albizia and Grewia (6 species each, Acacia and Bauhinia (5 species each.  Forty-five percent of the species were indigenous. This illustrates the diversity of the tree species in the studied area of the Eastern Ghats and also emphasizes the need for their conservation. 

Disrupting mycorrhizal mutualisms: a potential mechanism by which exotic tamarisk outcompetes native cottonwoods.

Science.gov (United States)

Meinhardt, Kelley A; Gehring, Catherine A

2012-03-01

The disruption of mutualisms between plants and mycorrhizal fungi is a potentially powerful mechanism by which invasives can negatively impact native species, yet our understanding of this mechanism's role in exotic species invasion is still in its infancy. Here, we provide several lines of evidence indicating that invasive tamarisk (Tamarix sp.) negatively affects native cottonwoods (Populus fremontii) by disrupting their associations with arbuscular mycorrhizal (AM) and ectomycorrhizal (EM) fungi. At a field site in the early stages of tamarisk invasion, cottonwoods with tamarisk neighbors had reduced EM colonization and altered EM fungal community composition relative to cottonwoods with native neighbors, leading to reductions in EM propagule abundance in the soil beneath tamarisk. Similarly, AM colonization of cottonwoods was reduced with a tamarisk neighbor, but there were no significant changes in AM fungal spore communities or propagule abundance. Root colonization by nonmycorrhizal fungi, including potential pathogens, was higher in cottonwoods with tamarisk neighbors. A greenhouse experiment in which AM and EM inoculation and plant neighbor were manipulated in a fully factorial design showed that cottonwoods benefited from mycorrhizas, especially EM, in terms of shoot biomass when grown with a conspecific, but shoot biomass was similar to that of nonmycorrhizal controls when cottonwoods were grown with a tamarisk neighbor. These results are partially explained by a reduction in EM but not AM colonization of cottonwoods by a tamarisk neighbor. Tamarisk neighbors negatively affected cottonwood specific leaf area, but not chlorophyll content, in the field. To pinpoint a mechanism for these changes, we measured soil chemistry in the field and the growth response of an EM fungus (Hebeloma crustuliniforme) to salt-amended media in the laboratory. Tamarisk increased both NO3- concentrations and electrical conductivity 2.5-fold beneath neighboring cottonwoods in

Recent tree cover increases in eastern China linked to low, declining human pressure, steep topography, and climatic conditions favoring tree growth.

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Jonas Nüchel

Full Text Available Globally, the extent of forest continues to decline, however, some countries have increased their forest extent in recent years. China is one of these countries and has managed to increase their tree cover through huge reforestation and afforestation programs during recent decades as well as land abandonment dynamics. This study investigates tree cover change in the eastern half of China between 2000 and 2010 on three different scales, using random forest modeling of remote sensing data for tree cover in relation to environmental and anthropogenic predictor variables. Our results show that between the years 2000 and 2010 2,667,875 km2 experienced an increase in tree cover while 1,854,900 km2 experienced a decline in tree cover. The area experiencing ≥10% increase in tree cover is almost twice as large as the area with ≥10% drop in tree cover. There is a clear relation between topography and tree cover change with steeper and mid-elevation areas having a larger response on tree cover increase than other areas. Furthermore, human influence, change in population density, and actual evapotranspiration are also important factors in explaining where tree cover has changed. This study adds to the understanding of tree cover change in China, as it has focus on the entire eastern half of China on three different scales and how tree cover change is linked to topography and anthropogenic pressure. Though, our results show an increase in tree cover in China, this study emphasizes the importance of incorporating anthropogenic factors together with biodiversity protection into the reforestation and afforestation programs in the future.

Recent tree cover increases in eastern China linked to low, declining human pressure, steep topography, and climatic conditions favoring tree growth.

Science.gov (United States)

Nüchel, Jonas; Svenning, Jens-Christian

2017-01-01

Globally, the extent of forest continues to decline, however, some countries have increased their forest extent in recent years. China is one of these countries and has managed to increase their tree cover through huge reforestation and afforestation programs during recent decades as well as land abandonment dynamics. This study investigates tree cover change in the eastern half of China between 2000 and 2010 on three different scales, using random forest modeling of remote sensing data for tree cover in relation to environmental and anthropogenic predictor variables. Our results show that between the years 2000 and 2010 2,667,875 km2 experienced an increase in tree cover while 1,854,900 km2 experienced a decline in tree cover. The area experiencing ≥10% increase in tree cover is almost twice as large as the area with ≥10% drop in tree cover. There is a clear relation between topography and tree cover change with steeper and mid-elevation areas having a larger response on tree cover increase than other areas. Furthermore, human influence, change in population density, and actual evapotranspiration are also important factors in explaining where tree cover has changed. This study adds to the understanding of tree cover change in China, as it has focus on the entire eastern half of China on three different scales and how tree cover change is linked to topography and anthropogenic pressure. Though, our results show an increase in tree cover in China, this study emphasizes the importance of incorporating anthropogenic factors together with biodiversity protection into the reforestation and afforestation programs in the future.

Cottonwood Response to Nitrogen Related To Plantation Age and Site

Science.gov (United States)

B.G. Blackmon

1977-01-01

When applied at plantation age 4,336 kg N/ha increased diameter growth of cottonwood on Sharkey clay by 33 percent over unfertilized controls. Fertilizing at ages 2 and 3 resulted in no response, nor was there any benefit from applying nitrogen fertilizer to cottonwood on Commerce silt loam. On both sites, foliar N levels were increased by fertilization regardless of...

Development of a spatially-distributed hydroecological model to simulate cottonwood seedling recruitment along rivers.

Science.gov (United States)

Benjankar, Rohan; Burke, Michael; Yager, Elowyn; Tonina, Daniele; Egger, Gregory; Rood, Stewart B; Merz, Norm

2014-12-01

Dam operations have altered flood and flow patterns and prevented successful cottonwood seedling recruitment along many rivers. To guide reservoir flow releases to meet cottonwood recruitment needs, we developed a spatially-distributed, GIS-based model that analyzes the hydrophysical requirements for cottonwood recruitment. These requirements are indicated by five physical parameters: (1) annual peak flow timing relative to the interval of seed dispersal, (2) shear stress, which characterizes disturbance, (3) local stage recession after seedling recruitment, (4) recruitment elevation above base flow stage, and (5) duration of winter flooding, which may contribute to seedling mortality. The model categorizes the potential for cottonwood recruitment in four classes and attributes a suitability value at each individual spatial location. The model accuracy was estimated with an error matrix analysis by comparing simulated and field-observed recruitment success. The overall accuracies of this Spatially-Distributed Cottonwood Recruitment model were 47% for a braided reach and 68% for a meander reach along the Kootenai River in Idaho, USA. Model accuracies increased to 64% and 72%, respectively, when fewer favorability classes were considered. The model predicted areas of similarly favorable recruitment potential for 1997 and 2006, two recent years with successful cottonwood recruitment. This model should provide a useful tool to quantify impacts of human activities and climatic variability on cottonwood recruitment, and to prescribe instream flow regimes for the conservation and restoration of riparian woodlands. Copyright © 2014 Elsevier Ltd. All rights reserved.

Photo guide for estimating risk to hardwood trees during prescribed burning operations in eastern oak forests

Science.gov (United States)

Patrick H. Brose

2009-01-01

A field guide of 40 photographs of common hardwood trees of eastern oak forests and fuel loadings surrounding their bases. The guide contains instructions on how to rapidly assess a tree's likelihood to be damaged or killed by prescribed burning.

Effects of Warming on Tree Species’ Recruitment in Deciduous Forests of the Eastern United States

Energy Technology Data Exchange (ETDEWEB)

Melillo, Jerry M. [Marine Biological Lab., Woods Hole, MA (United States); Clark, James S. [Duke Univ., Durham, NC (United States); Mohan, Jacqueline [Univ. of Georgia, Athens, GA (United States)

2015-03-25

Climate change is restructuring forests of the United States, although the details of this restructuring are currently uncertain. Rising temperatures of 2 to 8oC and associated changes in soil moisture will shift the competitive balance between species that compete for light and water, and so change their abilities to produce seed, germinate, grow, and survive. We have used large-scale experiments to determine the effects of warming on the most sensitive stage of species distributions, i.e., recruitment, in mixed deciduous forests in southern New England and in the Piedmont region of North Carolina. Two questions organized our research: (1) Might temperate tree species near the “warm” end of their range in the eastern United States decline in abundance during the coming century due to projected warming? and (2) Might trees near the “cool” end of their range in the eastern United States increase in abundance, or extend their range, during the coming 100 years because of projected warming? To explore these questions, we exposed seedlings to air and soil warming experiments in two eastern deciduous forest sites; one at the Harvard Forest (HF) in central Massachusetts, and the other at the Duke Forest (DF) in the Piedmont region of North Carolina. We focused on tree species common to both Harvard and Duke Forests (such as red, black, and white oaks), those near northern range limits (black oak, flowing dogwood, tulip poplar), and those near southern range limits (yellow birch, sugar maple, Virginia pine). At each site, we planted seeds and seedlings in common gardens established in temperature-controlled, open-top chambers. The experimental design was replicated and fully factorial and involved three temperature regimes (ambient, +3oC and +5oC) and two light regimes (closed forest canopy (low light) and gap conditions (high light)). Measured variables included Winter/Spring responses to temperature and mid-Summer responses to low soil moisture. This research

Environmental Assessment for BRAC Facilities and Remote Field Training Site, Wright-Patterson Air Force Base

Science.gov (United States)

2008-03-01

survey (BHE, 2001). Radio tracking of these two bats confirmed the presence of a maternity colony in a dead slippery elm (Ulmus rubra) in a woodlot...The most common trees observed were black walnut (Juglans nigra), elm (Ulmus spp.), eastern cottonwood, willow, ash (Fraxinus americana), sycamore

Summer Roost Tree Selection by Eastern Red, Seminole, and Evening Bats in the Upper Coastal Plain of South Carolina

Energy Technology Data Exchange (ETDEWEB)

Menzel, M.A.; Carter, T.C.; Ford, W.M.; Chapman, B.R.; Ozier, J.

2000-01-01

Radiotraction of six eastern red bats, six seminole bats and twenty-four evening bats to 55, 61, and 65 day roosts during 1996 to 1997 in the Upper Coastal Plain of South Carolina. For each species, testing was done for differences between used roost trees and randomly located trees. Also tested for differences between habitat characteristics surrounding roost trees and randomly located trees. Eastern Red and Seminole bats generally roosted in canopies of hardwood and pine while clinging to foilage and small branches. Evening bats roosted in cavities or under exfoliating bark in pines and dead snags. Forest management strategies named within the study should be beneficial for providing roosts in the Upper Coastal Plain of South Carolina.

New records, names and combinations of scaly tree ferns (Cyatheaceae) in eastern Malesia

NARCIS (Netherlands)

Coritico, F.P.; Amoroso, V.B.; Lehnert, M.

2017-01-01

Several scaly tree ferns (Cyatheaceae) from eastern Malesia are transferred from Cyathea s.lat. to other genera: Alsophila roroka from Sulawesi; Alsophila lamoureuxii from New Guinea; Alsophila binayana, A. bisquamata, A. mapahuwensis, A. murkelensis, A. ohaensis, and Sphaeropteris pukuana from

Production, transport, and metabolism of ethanol in eastern cottonwood

International Nuclear Information System (INIS)

MacDonald, R.C.

1991-01-01

In plant tissues, the production of acetaldehyde and ethanol are usually thought to occur as a mechanism to allow tolerance of hypoxic conditions. Acetaldehyde and ethanol were found to be common in vascular cambium and the transpiration stream of trees. Ethanol concentrations in the vascular cambium of Populus deltoides were not changed by placing logs from nonflooded trees in a pure oxygen environment for as long as 96 h, but increased by almost 3 orders of magnitude when exposed to low external pO 2 s. Ethanol is present in the xylem sap of flooded and nonflooded trees. Because of the constitutive presence of alcohol dehydrogenase in the mature leaves of woody plants, it was hypothesized that the leaves and shoots of trees had the ability to metabolize ethanol supplied by the transpiration stream. 1-[ 14 C]ethanol was supplied to excised leaves and shoots of Populus deltoides Bartr. in short- and long-term experiments. Greater than 99% of the radiolabel was incorporated into plant tissue in short-term experiments, with more than 95% of the label remaining in plant tissue after 24 h. Very little label reached the leaf mesophyll cells of excised shoots, as revealed by autoradiography. Radiolabel appeared primarily in the water- and chloroform-soluble fractions in short-term experiments, while in long-term experiments, label was also incorporated into protein. When labelled ethanol was supplied to excised petioles in a 5 min pulse, 41% of the label was incorporated into organic acids. Some label was also incorporated into amino acids, protein, and the chloroform-soluble fraction, with very little appearing in neutral sugars, starch, or the insoluble pellet. Labelled organic acids were separated by HPLC, and were comprised of acetate, isocitrate, α-ketoglutarate, and succinate. There was no apparent incorporation of label into phosphorylated compounds

Tree roosting by male and female eastern pipistrelles in a forested landscape

Science.gov (United States)

Roger W. Perry; Ronald E. Thill

2007-01-01

Little information has been published on selection of tree roosts by eastern pipistrelles (Perimyotis subflavus) in forested environments, and no radiotelemetry-based studies have been conducted on males in forested settings. Therefore, we used radiotelemetry to characterize summer roost selection by 21 male (33 roosts) and 7 female (14 roosts)...

Predicting Potential Changes in Suitable Habitat and Distribution by 2100 for Tree Species of the Eastern United States

Science.gov (United States)

Louis R Iverson; Anantha M. Prasad; Mark W. Schwartz; Mark W. Schwartz

2005-01-01

We predict current distribution and abundance for tree species present in eastern North America, and subsequently estimate potential suitable habitat for those species under a changed climate with 2 x CO2. We used a series of statistical models (i.e., Regression Tree Analysis (RTA), Multivariate Adaptive Regression Splines (MARS), Bagging Trees (...

Mechanisms of Cottonwood Establishment in Gravel-Bed Rivers, across Scales from the Bar to the Reach

Science.gov (United States)

Meier, C. I.

2017-12-01

Riparian cottonwoods are pioneer trees adapted to colonizing fluvial corridors, with strong effects on ecosystem structure and function. As their populations are being affected by flow alterations and invasive species, their recruitment mechanisms need to be understood, to support scientifically-based restoration efforts. I propose new concepts for cottonwood establishment in gravelly streams, from the local to the reach scale. These notions complement the currently-accepted ideas, which apply only to the landscape scale, and whose basic assumptions (existence of an alluvial water table, which is planar, almost horizontal, and linked to the river stage, with a parallel, spatially-uniform capillary fringe) seem to be based on a physical template that is only valid in the case of sand-bed streams. At the local, within-the-bar scale, two concepts drive establishment success. First, a finer matrix material helps retain more capillary water after the yearly snowmelt flood or a precipitation event. Second, the coarse surface layer of clean gravel and cobble acts as rock mulch, strongly decreasing evaporative losses. At the reach scale, we find that the commonly reported arcuate bands of cottonwoods do not depend on groundwater, but are caused by water dispersal (hydrochory). Wind-dispersed seeds fall into the river, are entrained into the drift, and start germinating as they travel under water. Some of the seeds and germinants find their way into the shallow, high relative roughness flow along the cobble shoreline. They are able to deposit in this environment, where they start growing, also under water. As waters recede, during the period of seed availability in the drift, the river seeds its banks and bars. Thus, the boundaries of observed bands and patches with successful seedling recruitment correspond to the location of flow profiles at different dates during the flood recession.

Leaf water relations and sapflow in eastern cottonwood (Populus deltoides Bartr.) trees planted for phytoremediation of a groundwater pollutant

Science.gov (United States)

James M. Vose; Wayne T. Swank; Gregory J. Harvey; Barton D. Clinton; Christine Sobek

2000-01-01

Plants that remediate groundwater pollutants may offer a feasible alternative to the traditional and more expensive practices. Because its success depends on water use, this approach requires a complete understanding of species-specific transpiration patterns. The objectives of this study were (1) to quantify tree and stand-level transpiration in two age classes (whips...

Disturbance Level Determines the Regeneration of Commercial Tree Species in the Eastern Amazon

NARCIS (Netherlands)

Schwartz, G.; Lopes, J.C.; Kanashiro, M.; Mohren, G.M.J.; Pena Claros, M.

2014-01-01

The effects of reduced-impact logging (RIL) on the regeneration of commercial tree species were investigated, as long-term timber yields depend partly on the availability of seedlings in a managed forest. On four occasions during a 20-month period in the Tapajós National Forest (Eastern Amazon,

Hydrogeochemical and stream sediment detailed geochemical survey for Thomas Range-Wasatch, Utah. Cottonwood project area

International Nuclear Information System (INIS)

Butz, T.R.; Bard, C.S.; Witt, D.A.; Helgerson, R.N.; Grimes, J.G.; Pritz, P.M.

1980-01-01

Results of Cottonwood project area of the Thomas Range-Wasatch detailed geochemical survey are reported. Field and laboratory data are presented for 15 groundwater samples, 79 stream sediment samples, and 85 radiometric readings. Statistical and areal distributions of uranium and possible uranium-related variables are given. A generalized geologic map of the project area is provided, and pertinent geologic factors which may be of significance in evaluating the potential for uranium mineralization are briefly discussed. Uranium concentrations in groundwater range from 0.25 to 3.89 ppB. The highest concentrations are from groundwaters from the Little Cottonwood and Ferguson Stocks. Variables that appear to be associated with uranium in groundwater include cobalt, iron, potassium, manganese, nickel, sulfate, and to a lesser extent, molybdenum and strontium. This association is attributed to the Monzonitic Little Cottonwood Stock, granodioritic to granitic and lamprophyric dikes, and known sulfide deposits. Soluble uranium concentrations (U-FL) in stream sediments range from 0.31 to 72.64 ppM. Total uranium concentrations (U-NT) range from 1.80 to 75.20 ppM. Thorium concentrations range from <2 to 48 ppM. Anomalous values for uranium and thorium are concentrated within the area of outcrop of the Little Cottonwood and Ferguson Stocks. Variables which are areally associated with high values of uranium, thorium, and the U-FL:U-NT ratio within the Little Cottonwood Stock are barium, copper, molybdenum, and zinc. High concentrations of these variables are located near sulfide deposits within the Little Cottonwood Stock

Soil carbon, after 3 years, under short-rotation woody crops grown under varying nutrient and water availability

Science.gov (United States)

Felipe G. Sanchez; Mark Coleman; Charles T. Garten; Robert J. Luxmoore; John A. Stanturf; Carl Trettin; Stan D. Wullschleger

2007-01-01

Soil carbon contents were measured on a short-rotation woody crop study located on the US Department of Energy's Savannah River Site outside Aiken, SC. This study included fertilization and irrigation treatments on five tree genotypes (sweetgum, loblolly pine, sycamore and two eastern cottonwood clones). Prior to study installation, the previous pine stand was...

A Hierarchical Analysis of Tree Growth and Environmental Drivers Across Eastern US Temperate Forests

Science.gov (United States)

Mantooth, J.; Dietze, M.

2014-12-01

Improving predictions of how forests in the eastern United States will respond to future global change requires a better understanding of the drivers of variability in tree growth rates. Current inventory data lack the temporal resolution to characterize interannual variability, while existing growth records lack the extent required to assess spatial scales of variability. Therefore, we established a network of forest inventory plots across ten sites across the eastern US, and measured growth in adult trees using increment cores. Sites were chosen to maximize climate space explored, while within sites, plots were spread across primary environmental gradients to explore landscape-level variability in growth. Using the annual growth record available from tree cores, we explored the responses of trees to multiple environmental covariates over multiple spatial and temporal scales. We hypothesized that within and across sites growth rates vary among species, and that intraspecific growth rates increase with temperature along a species' range. We also hypothesized that trees show synchrony in growth responses to landscape-scale climatic changes. Initial analyses of growth increments indicate that across sites, trees with intermediate shade tolerance, e.g. Red Oak (Quercus rubra), tend to have the highest growth rates. At the site level, there is evidence for synchrony in response to large-scale climatic events (e.g. prolonged drought and above average temperatures). However, growth responses to climate at the landscape scale have yet to be detected. Our current analysis utilizes hierarchical Bayesian state-space modeling to focus on growth responses of adult trees to environmental covariates at multiple spatial and temporal scales. This predictive model of tree growth currently incorporates observed effects at the individual, plot, site, and landscape scale. Current analysis using this model shows a potential slowing of growth in the past decade for two sites in the

Flow regime effects on mature Populus fremontii (Fremont cottonwood) productivity on two contrasting dryland river floodplains

Science.gov (United States)

Andersen, Douglas C.

2016-01-01

I compared riparian cottonwood (Populus fremontii) productivity-discharge relationships in a relictual stand along the highly regulated Green River and in a naturally functioning stand along the unregulated Yampa River in semiarid northwest Colorado. I used multiple regression to model flow effects on annual basal area increment (BAI) from 1982 to 2011, after removing any autocorrelation present. Each BAI series was developed from 20 trees whose mean size (67 cm diameter at breast height [DBH]) was equivalent in the two stands. BAI was larger in the Yampa River stand except in 2 y when defoliating leaf beetles were present there. I found no evidence for a Yampa flood-magnitude threshold above which BAI declined. Flow variables explained ∼45% of residual BAI variability, with most explained by current-year maximum 90-d discharge (QM90) in the Yampa River stand and by a measure of the year-to-year change in QM90 in the Green River stand. The latter reflects a management-imposed ceiling on flood magnitude—Flaming Gorge Dam power plant capacity—infrequently exceeded during the study period. BAI in the relictual stand began to trend upward in 1992 when flows started to mimic a natural flow regime. Mature Fremont cottonwoods appear to be ecologically resilient. Their productivity along regulated rivers might be optimized using multiyear environmental flow designs.

In Situ Remediation of a TCE-Contaminated Aquifer Using a Short Rotation Woody Crop Groundwater Treatment System

Science.gov (United States)

2006-05-01

eastern cottonwoods, six oaks, two live oak, three cedars, two willows, one hackberry, one pecan , one pine, one American elm, one unidentified...hackberry, 1 pecan , 1 pine, 1 American elm, 1 unidentified elm, and 1 unidentified species. Cores were collected from a height of approximately 1.5 m above...of trees to act as pumps was noted in the late 19th century when eucalyptus trees were planted in Italy and Algeria to dry up marshes (USEPA, 2003

Effects of stand and inter-specific stocking on maximizing standing tree carbon stocks in the eastern United States

Science.gov (United States)

Christopher W. Woodall; Anthony W. D' Amato; John B. Bradford; Andrew O. Finley

2011-01-01

There is expanding interest in management strategies that maximize forest carbon (C) storage to mitigate increased atmospheric carbon dioxide. The tremendous tree species diversity and range of stand stocking found across the eastern United States presents a challenge for determining optimal combinations for the maximization of standing tree C storage. Using a...

Unmanned aerial survey of fallen trees in a deciduous broadleaved forest in eastern Japan.

Science.gov (United States)

Inoue, Tomoharu; Nagai, Shin; Yamashita, Satoshi; Fadaei, Hadi; Ishii, Reiichiro; Okabe, Kimiko; Taki, Hisatomo; Honda, Yoshiaki; Kajiwara, Koji; Suzuki, Rikie

2014-01-01

Since fallen trees are a key factor in biodiversity and biogeochemical cycling, information about their spatial distribution is of use in determining species distribution and nutrient and carbon cycling in forest ecosystems. Ground-based surveys are both time consuming and labour intensive. Remote-sensing technology can reduce these costs. Here, we used high-spatial-resolution aerial photographs (0.5-1.0 cm per pixel) taken from an unmanned aerial vehicle (UAV) to survey fallen trees in a deciduous broadleaved forest in eastern Japan. In nine sub-plots we found a total of 44 fallen trees by ground survey. From the aerial photographs, we identified 80% to 90% of fallen trees that were >30 cm in diameter or >10 m in length, but missed many that were narrower or shorter. This failure may be due to the similarity of fallen trees to trunks and branches of standing trees or masking by standing trees. Views of the same point from different angles may improve the detection rate because they would provide more opportunity to detect fallen trees hidden by standing trees. Our results suggest that UAV surveys will make it possible to monitor the spatial and temporal variations in forest structure and function at lower cost.

Ten-Year Performance of Eastern White Pine - under a Crop Tree Release Regime on an Outwash Site

Science.gov (United States)

Kenneth M. Desmarais; William B. Leak; William B. Leak

2005-01-01

A young stand of eastern white pine aged 38-40 years received a crop tree release cutting reducing stocking to 100 tree/ac. This stocking level reflects the number of sterms per acre that would be contained in a well stocked mature stand at final harvest (20-in. quadratic mean stand diameter). The stand then was monitored for growth and value change. Stems that grew...

Planting Season for Cottonwood Can Be Extended

Science.gov (United States)

Harvey E. Kennedy

1979-01-01

Cottonwood cuttings planted as early as November and as late as May survive and grow well if sufficient soil moisture is available and cuttings are properly handled. About 6 inches or more of well distributed rainfall is needed in September and October to recharge Commerce soil. If these two months are dry, planting should be delayed. In March or later, cuttings should...

Environmental tolerance of an invasive riparian tree and its potential for continued spread in the southwestern US

Science.gov (United States)

Reynolds, L.V.; Cooper, D.J.

2010-01-01

Questions: Exotic plant invasion may be aided by facilitation and broad tolerance of environmental conditions, yet these processes are poorly understood in species-rich ecosystems such as riparian zones. In the southwestern United States (US) two plant species have invaded riparian zones: tamarisk (Tamarix ramosissima, T. chinensis, and their hybrids) and Russian olive (Elaeagnus angustifolia). We addressed the following questions: (1) is Russian olive able to tolerate drier and shadier conditions than cottonwood and tamarisk? (2) Can tamarisk and cottonwood facilitate Russian olive invasion? Location: Arid riparian zones, southwestern US. Methods: We analyzed riparian tree seedling requirements in a controlled experiment, performed empirical field studies, and analyzed stable oxygen isotopes to determine the water sources used by Russian olive. Results: Russian olive survival was significantly higher in dense shade and low moisture conditions than tamarisk and cottonwood. Field observations indicated Russian olive established where flooding cannot occur, and under dense canopies of tamarisk, cottonwood, and Russian olive. Tamarisk and native riparian plant species seedlings cannot establish in these dry, shaded habitats. Russian olive can rely on upper soil water until 15 years of age, before utilizing groundwater. Conclusions: We demonstrate that even though there is little evidence of facilitation by cottonwood and tamarisk, Russian olive is able to tolerate dense shade and low moisture conditions better than tamarisk and cottonwood. There is great potential for continued spread of Russian olive throughout the southwestern US because large areas of suitable habitat exist that are not yet inhabited by this species. ?? 2010 International Association for Vegetation Science.

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

Atlas of current and potential future distributions of common trees of the eastern United States

Science.gov (United States)

Louis R. Iverson; Anantha M. Prasad; Betsy J. Hale; Elaine Kennedy Sutherland

1999-01-01

This atlas documents the current and possible future distribution of 80 common tree species in the Eastern United States and gives detailed information on environmental characteristics defining these distributions. Also included are outlines of life history characteristics and summary statistics for these species. Much of the data are derived from Forest Inventory and...

Water Resources and Related Land Management, Buffalo Metropolitan Area, New York

Science.gov (United States)

1991-04-01

nettle , Queen Ann’s lace, aster (New England, bushy), beggarstick, cocklebur, chickory, tickseed-sunflower, timothy, teasel, and grasses (quake, orchard...in leaf litter and falling insects off such overhanging trees, that contribute to the fish food chain in the creek. Channelization would disrupt and...alder and eastern cottonwood. Goldenrod, stinging nettle and various grasses are abundant to common. Aquatic vegetation is limited, although spikerush

The Cottonwood Lake study area, a long-term wetland ecosystem monitoring site

Science.gov (United States)

Mushet, David M.; Euliss, Ned H.

2012-01-01

The Cottonwood Lake study area is one of only three long-term wetland ecosystem monitoring sites in the prairie pothole region of North America; the other two are Orchid Meadows in South Dakota and St. Denis in Saskatchewan. Of the three, Cottonwood Lake has, by far, the longest continuous data-collection record. Research was initiated at the study area in 1966, and intensive investigations of the hydrology, chemistry, and biology of prairie pothole wetlands continue at the site today. This fact sheet describes the study area, provides an overview of wetland ecology research that has been conducted at the site in the past, and provides an introduction to current work being conducted at the study area by USGS scientists.

Initial effects of quinclorac on the survival and growth of high biomass tree species

Directory of Open Access Journals (Sweden)

Joshua P. Adams

2017-07-01

Full Text Available Increasingly, short rotation woody crops are being planted for biofuel/biomass production on unused lands or marginal agricultural lands. Many of these plantations occur near agriculture land which is intensively managed including yearly herbicide applications. Herbicide drift from these applications may cause tree stress and decreasing yields impacting potential biomass production. Quinclorac, a rice herbicide, is often cited as a potential source of tree damage and is the focal herbicide of this study. Five planting stocks, including three eastern cottonwood clones, a hybrid poplar clone, and American sycamore, were assessed for herbicide affects and deployed at three sites across south Arkansas. Stocks were exposed to a full rate labeled for rice (3.175 L ha-1, two rates simulating drift (1/100th and 1/10th the full rate, and a no-spray control. Survival of all Populus clones decreased drastically as quinclorac rate increased, while there was little observed effect on American sycamore. Some variability in treatment response among poplars occurred below the full herbicide rate; however, direct spraying a full herbicide rate on poplars resulted in survival rates below 65 percent and negative growth rates due to dieback. Conversely, photosynthetic rates of remaining leaves increased as quinclorac rate increased. Survival and damage scores of American sycamore, regardless of herbicide rate, remained nearly constant.

Tree shelters and other methods for reducing deer damage to hardwood regeneration in the eastern United States

Science.gov (United States)

Gary W. Miller

1998-01-01

This report summarizes the basic silvicultural problems associated with regenerating commercial hardwood (broadleaf) species in the eastern United States and includes a review of current methods used to reduce the impact of deer browsing. The following topics are discussed: 1) the biological requirements and regeneration mechanism associated with several important tree...

Tree diversity in the tropical dry forest of Bannerghatta National Park in Eastern Ghats, Southern India

Directory of Open Access Journals (Sweden)

Gopalakrishna S. Puttakame

2015-12-01

Full Text Available Tree species inventories, particularly of poorly known dry deciduous forests, are needed to protect and restore forests in degraded landscapes. A study of forest stand structure, and species diversity and density of trees with girth at breast height (GBH ≥10 cm was conducted in four management zones of Bannerghatta National Park (BNP in the Eastern Ghats of Southern India. We identified 128 tree species belonging to 45 families in 7.9 hectares. However, 44 species were represented by ≤ 2 individuals. Mean diversity values per site for the dry forest of BNP were: tree composition (23.8 ±7.6, plant density (100.69 ± 40.02, species diversity (2.56 ± 0.44 and species richness (10.48 ± 4.05. Tree diversity was not significantly different (P>0.05 across the four management zones in the park. However, the number of tree species identified significantly (P<0.05 increased with increasing number of sampling sites, but majority of the species were captured. Similarly, there were significant variations (p<0.05 between tree diameter class distributions. Juveniles accounted for 87% of the tree population. The structure of the forest was not homogeneous, with sections ranging from poorly structured to highly stratified configurations. The study suggests that there was moderate tree diversity in the tropical dry thorn forest of Bannerghatta National Park, but the forest was relatively young.

[A review of the genomic and gene cloning studies in trees].

Science.gov (United States)

Yin, Tong-Ming

2010-07-01

Supported by the Department of Energy (DOE) of U.S., the first tree genome, black cottonwood (Populus trichocarpa), has been completely sequenced and publicly release. This is the milestone that indicates the beginning of post-genome era for forest trees. Identification and cloning genes underlying important traits are one of the main tasks for the post-genome-era tree genomic studies. Recently, great achievements have been made in cloning genes coordinating important domestication traits in some crops, such as rice, tomato, maize and so on. Molecular breeding has been applied in the practical breeding programs for many crops. By contrast, molecular studies in trees are lagging behind. Trees possess some characteristics that make them as difficult organisms for studying on locating and cloning of genes. With the advances in techniques, given also the fast growth of tree genomic resources, great achievements are desirable in cloning unknown genes from trees, which will facilitate tree improvement programs by means of molecular breeding. In this paper, the author reviewed the progress in tree genomic and gene cloning studies, and prospected the future achievements in order to provide a useful reference for researchers working in this area.

Extinction debt and colonization credit delay range shifts of eastern North American trees

DEFF Research Database (Denmark)

Talluto, Matthew V.; Boulangeat, Isabelle; Vissault, Steve

2017-01-01

and biodiversity of forests, because they can result in 'extinction debts', where populations temporarily persist under unsuitable conditions, and 'colonization credits', where suitable locations are not occupied owing to slow demography and limited dispersal. Here we use a range dynamics model based...... on metapopulation theory to show that the distributions of 21 dominant trees in eastern North America are out of equilibrium with climate and demonstrate both extinction debt and colonization credit. Moreover, lags are more severe at northern range limits, suggesting that range contraction in response to warming...

Red Cedar Invasion Along the Missouri River, South Dakota: Cause and Consequence

Science.gov (United States)

Greene, S.; Knox, J. C.

2012-12-01

This research evaluates drivers of and ecosystem response to red cedar (Juniperus virginiana) invasion of riparian surfaces downstream of Gavin's Point Dam on the Missouri River. Gavin's Point Dam changed the downstream geomorphology and hydrology of the river and its floodplain by reducing scouring floods and flood-deposited sediment. The native cottonwood species (Populus deltoides) favors cleared surfaces with little to no competitors to establish. Now that there are infrequent erosive floods along the riparian surfaces to remove competitor seeds and seedlings, other vegetation is able to establish. Red cedar is invading the understory of established cottonwood stands and post-dam riparian surfaces. To assess reasons and spatial patterns for the recent invasion of red cedar, a stratified random sampling of soil, tree density and frequency by species, and tree age of 14 forest stands was undertaken along 59 river kilometers of riparian habitat. Soil particle size was determined using laser diffraction and tree ages were estimated from ring counts of tree cores. As an indicator of ecosystem response to invasion, we measured organic matter content in soil collected beneath red cedar and cottonwood trees at three different depths. Of 565 red cedars, only two trees were established before the dam was built. We applied a multiple regression model of red cedar density as a function of cottonwood density and percent sand (63-1000 microns in diameter) in StatPlus© statistical software. Cottonwood density and percent sand are strongly correlated with invasion of red cedar along various riparian surfaces (n = 59, R2 = 0.42, p-values cedar and cottonwood trees (p-value > 0.05 for all depths). These findings suggest that the dam's minimization of downstream high-stage flows opened up new habitat for red cedar to establish. Fluvial geomorphic surfaces reflect soil type and cottonwood density and, in turn, predict susceptibility of a surface to red cedar invasion. Nonetheless

Status and Trend of Cottonwood Forests Along the Missouri River

Science.gov (United States)

2010-03-03

Rhamnus davurica), green ash, chokecherry ( Prunus virginiana ), and some Russian olive (Figure 30a). Younger cottonwood (all sapling stands, and...argentea), common chokecherry ( Prunus virginiana ), service berry (Amelanchier spp.) and rarely, red-osier dogwood (Cornus stolonifera) (Figure 32). In...sagebrush (Artemisia cana), common chokecherry ( Prunus virginiana ), and rarely, red-osier dogwood (Cornus stolonifera) (Ross and Hunter 1976, Scott

Dynamics of Plains Cottonwood ( Populus deltoides) Forests and Historical Landscape Change along Unchannelized Segments of the Missouri River, USA

Science.gov (United States)

Dixon, Mark D.; Johnson, W. Carter; Scott, Michael L.; Bowen, Daniel E.; Rabbe, Lisa A.

2012-05-01

Construction of six large dams and reservoirs on the Missouri River over the last 50-75 years has resulted in major landscape changes and alterations in flow patterns, with implications for riparian forests dominated by plains cottonwood ( Populus deltoides). We quantified changes in land cover from 1892-1950s and the 1950s-2006 and the current extent and age structure of cottonwood forests on seven segments (two reservoir and five remnant floodplain) comprising 1127 km (53 %) of the unchannelized upper two-thirds of the Missouri River. Riparian forest area declined by 49 %; grassland 61 %; shrubland 52 %; and sandbar habitat 96 %; while agricultural cropland increased six-fold and river/reservoir surface area doubled from 1892 to 2006. Net rates of erosion and accretion declined between the 1892-1950s and 1950s-2006 periods. Accretion exceeded erosion on remnant floodplain segments, resulting in declines in active channel width, particularly in 1950s-2006. Across all study segments in 2006, most cottonwood stands (67 %) were >50 years old, 22 % were 25-50 years old, and only 10 % were <25 years old. Among stands <50 years old, the higher proportion of 25-50 year old stands represents recruitment that accompanied initial post-dam channel narrowing; while declines in sandbar and shrubland area and the low proportion of stands <25 years old suggest declines in geomorphic dynamism and limited recruitment under recent river management. Future conservation and restoration efforts should focus both on limiting further loss of remnant cottonwood stands and developing approaches to restore river dynamics and cottonwood recruitment processes.

Riparian Cottonwood Ecosystems and Regulated Flows in Kootenai and Yakima Sub-Basins : Volume III (Overview and Tools).

Energy Technology Data Exchange (ETDEWEB)

Jamieson, Bob; Braatne, Jeffrey H.

2001-10-01

Riparian vegetation and especially cottonwood and willow plant communities are dependent on normative flows and especially, spring freshette, to provide conditions for recruitment. These plant communities therefore share much in common with a range of fish species that require natural flow conditions to stimulate reproduction. We applied tools and techniques developed in other areas to assess riparian vegetation in two very different sub-basins within the Columbia Basin. Our objectives were to: Document the historic impact of human activity on alluvial floodplain areas in both sub-basins; Provide an analysis of the impacts of flow regulation on riparian vegetation in two systems with very different flow regulation systems; Demonstrate that altered spring flows will, in fact, result in recruitment to cottonwood stands, given other land uses impacts on each river and the limitations imposed by other flow requirements; and Assess the applicability of remote sensing tools for documenting the distribution and health of cottonwood stands and riparian vegetation that can be used in other sub-basins.

Genetic improvement and evaluation of black cottonwood for short- rotation biomass production. Final report, 1987--1992

Energy Technology Data Exchange (ETDEWEB)

Stettler, R.F.; Hinckley, T.M. [Washington Univ., Seattle, WA (United States). Coll. of Forest Resources; Heilman, P.E. [Washington State Univ., Puyallup, WA (United States). Research and Extension Center; Bradshaw, H.D. Jr. [Washington Univ., Seattle, WA (United States). Dept. of Biochemistry

1993-04-30

This project was initiated in 1978 to serve three objectives: (1) develop genetically improved poplar cultivars offering increased productivity under short-rotation culture; (2) identify the major components of productivity in poplar and determine ways in which they can be manipulated, genetically and culturally; and (3) engage in technology transfer to regional industry and agencies so as to make poplar culture in the Pacific Northwest economically feasible. The project is aimed at capturing natural variation in the native black cottonwood. Populus trichocarpa T & G, and enhancing it through selective breeding. Major emphasis has been placed on hybridization of black cottonwood with P deltoides and P maximowiczii, more recently with p nigra. First-generation (F{sub 1}) hybrids have consistently outperformed black cottonwood by a factor of 1.5.-2. The high yields of woody biomass obtained from these clonally propagated hybrids, in rotations of 4-7 years, have fostered the establishment of large-scale plantations by the pulp and paper industry in the region. Physiological studies have helped to elucidate hybrid superiority and several of the underlying mechanisms.

Recruitment of hornbill-dispersed trees in hunted and logged forests of the Indian Eastern Himalaya.

Science.gov (United States)

Sethi, Pia; Howe, Henry F

2009-06-01

Hunting of hornbills by tribal communities is widespread in logged foothill forests of the Indian Eastern Himalaya. We investigated whether the decline of hornbills has affected the dispersal and recruitment of 3 large-seeded tree species. We hypothesized that 2 low-fecundity tree species, Chisocheton paniculatus and Dysoxylum binectariferum (Meliaceae) bearing arillate fruits, are more dispersal limited than a prolifically fruiting drupaceous tree Polyalthia simiarum (Annonaceae), which has potential dispersers other than hornbills. We estimated the abundance of large avian frugivores during the fruiting season along transects in 2 protected and 2 disturbed forests. We compared recruitment of the tree species near (Hornbills (Anthracoceros albirostris) were significantly lower in disturbed forests, but sites did not differ in abundances of the Mountain Imperial Pigeon (Ducula badia). Overall, tree species showed more severely depressed recruitment of seedlings (77% fewer) and juveniles (69% fewer) in disturbed than in protected forests. In disturbed forests, 93% fewer seedlings of C. paniculatus were beyond parental crowns, and a high number of all seedlings (42%) accumulated directly under reproductive adults. In contrast, D. binectariferum and P. simiarum were recruitment rather than dispersal limited, with fewer dispersed seedlings surviving in disturbed than in protected forests. Results are consistent with the idea that disturbance disrupts mutualisms between hornbills and some large-seeded food plants, with the caveat that role redundancy within even small and specialized disperser assemblages renders other tree species less vulnerable to loss of regular dispersal agents. ©2009 Society for Conservation Biology.

Wild food trees in Eastern Nuba Mountains, Sudan: Use diversity and threatening factors

Directory of Open Access Journals (Sweden)

Nagwa Kamal-Eldin M. Salih

2014-08-01

Full Text Available This study was conducted in 2010 in Eastern Nuba Mountains, Sudan to investigate ethnobotanical food and non-food uses of 16 wild edible fruit producing trees. Quantitative and qualitative information was collected from 105 individuals distributed in 7 villages using a semi-structured questionnaire. Also gathering of data was done using a number of rapid rural appraisal techniques, including key informant interviews, group discussion, secondary data sources and direct observations. Data was analysed using fidelity level and informant consensus factor methods to reveal the cultural importance of species and use category. Utilizations for timber products were found of most community importance than food usages, especially during cultivated food abundance. Balanites aegyptiaca, Ziziphus spina-christi and Tamarindus indica fruits were asserted as most preferable over the others and of high marketability in most of the study sites. Harvesting for timber-based utilizations in addition to agricultural expansion and overgrazing were the principal threats to wild edible food producing trees in the area. The on and off prevailing armed conflict in the area make it crucial to conserve wild food trees which usually play a more significant role in securing food supply during emergency times, especially in times of famine and wars. Increasing the awareness of population on importance of wild food trees and securing alternative income sources, other than wood products, is necessary in any rural development programme aiming at securing food and sustaining its resources in the area.

Age class, longevity and growth rate relationships: protracted growth increases in old trees in the eastern United States.

Science.gov (United States)

Johnson, Sarah E; Abrams, Marc D

2009-11-01

This study uses data from the International Tree-Ring Data Bank website and tree cores collected in the field to explore growth rate (basal area increment, BAI) relationships across age classes (from young to old) for eight tree species in the eastern US. These species represent a variety of ecological traits and include those in the genera Populus, Quercus, Pinus, Tsuga and Nyssa. We found that most trees in all age classes and species exhibit an increasing BAI throughout their lives. This is particularly unusual for trees in the older age classes that we expected to have declining growth in the later years, as predicted by physiological growth models. There exists an inverse relationship between growth rate and increasing age class. The oldest trees within each species have consistently slow growth throughout their lives, implying an inverse relationship between growth rate and longevity. Younger trees (trees when they are of the same age resulting from a higher proportion of fast-growing trees in these young age classes. Slow, but increasing, BAI in the oldest trees in recent decades is a continuation of their growth pattern established in previous centuries. The fact that they have not shown a decreasing growth rate in their old age contradicts physiological growth models and may be related to the stimulatory effects of global change phenomenon (climate and land-use history).

Tree mortality in the eastern Mediterranean, causes and implications under climatic change

Science.gov (United States)

Sarris, Dimitrios; Iacovou, Valentina; Hoch, Guenter; Vennetier, Michel; Siegwolf, Rolf; Christodoulakis, Dimitrios; Koerner, Christian

2015-04-01

The eastern Mediterranean has experienced repeated incidents of forest mortality related to drought in recent decades. Such events may become more frequent in the future as drought conditions are projected to further intensify due to global warming. We have been investigating the causes behind such forest mortality events in Pinus halepensis, (the most drought tolerant pine in the Mediterranean). We cored tree stems and sampled various tissue types from dry habitats close to sea level and explored growth responses, stable isotope signals and non-structural carbohydrate (NSC) concentrations. Under intense drought that coincided with pine desiccation events in natural populations our result indicate a significant reduction in tree growth, the most significant in more than a century despite the increase in atmospheric CO2 concentrations in recent decades. This has been accompanied by a lengthening in the integration periods of rainfall needed for pine growth, reaching even 5-6 years before and including the year of mortality occurrence. Oxygen stable isotopes indicate that these signals were associated with a shift in tree water utilization from deeper moisture pools related to past rainfall events. Furthermore, where the driest conditions occur, pine carbon reserves were found to increase in stem tissue, indicating that mortality in these pines cannot be explained by carbon starvation. Our findings suggest that for pine populations that are already water limited (i) a further atmospheric CO2 increase will not compensate for the reduction in growth because of a drier climate, (ii) hydraulic failure appears as the most likely cause of pine desiccation, as no shortage occurs in tree carbon reserves, (iii) a further increase in mortality events may cause these systems to become carbon sources.

Aboveground tree biomass in a recovering tropical sal (Shorea robusta Gaertn. f.) forest of Eastern Ghats, India

Energy Technology Data Exchange (ETDEWEB)

Behera, Soumit K.; Misra, Malaya K. [Ecology and Floristic Laboratory, Department of Botany, Berhampur University, Berhampur 760 007, Orissa (India)

2006-06-15

Aboveground biomass of individual tree species by component and total biomass per unit area for four different stages of a recovering tropical dry deciduous forest stands, dominated by sal (Shorea robusta Gaertn. f.) of the Eastern Ghats, India were investigated during 2001-2002. Different periods of recovering (2, 4, 6, and 10-year) forest stands (84{sup o}13'E, 20{sup o}29'N) were selected in the Kandhamal district of Orissa, India and sample trees of all species were harvested. Tree species diversity was 23, 23, 21 and 22 in 2, 4, 6, and 10-year recovering stands, respectively. Species-wise Ixora pavetta showed the highest biomass in 2 and 4-year stands while Shorea robusta in 6 and 10-year stands. Component-wise, in all species, bole-wood contribution ranged between 22.6% and 60.9%. Aboveground tree biomass, in all the stands, was dominated by Shorea robusta, which ranged between 12.68 and 231.91Mgha{sup -1}. Total aboveground tree biomass was 30.12, 49.21, 107.54 and 261.08Mgha{sup -1} in 2, 4, 6 and 10-year stands, respectively. (author)

Riparian Cottonwood Ecosystems and Regulated Flows in Kootenai and Yakima Sub-Basins : Volume II Yakima (Overview, Report, Appendices).

Energy Technology Data Exchange (ETDEWEB)

Jamieson, Bob; Braatne, Jeffrey H.

2001-10-01

Riparian vegetation and especially cottonwood and willow plant communities are dependent on normative flows and especially, spring freshette, to provide conditions for recruitment. These plant communities therefore share much in common with a range of fish species that require natural flow conditions to stimulate reproduction. We applied tools and techniques developed in other areas to assess riparian vegetation in two very different sub-basins within the Columbia Basin. Our objectives were to: Document the historic impact of human activity on alluvial floodplain areas in both sub-basins; Provide an analysis of the impacts of flow regulation on riparian vegetation in two systems with very different flow regulation systems; Demonstrate that altered spring flows will, in fact, result in recruitment to cottonwood stands, given other land uses impacts on each river and the limitations imposed by other flow requirements; and Assess the applicability of remote sensing tools for documenting the distribution and health of cottonwood stands and riparian vegetation that can be used in other sub-basins.

The effect of gamma irradiation on crude fibre NDF, ADF, and ADL of some Syrian agricultural residues

International Nuclear Information System (INIS)

Al-Masri, M.R.; Zarkawi, M.

1992-07-01

The effects of 150 KGy of gamma irradiation on crude fibre and its main components (cellulose, hemicellulose-cellulose and lignin) and on neutral detergent fibre (NDF), acid detergent lignin (ADL), and acid detergent fibre (ADF) were investigated. The results indicate that gamma irradiation decreased Cf content by 30%, 28%, 29%, and 17% for cottonwood, lentils straw, apple-tree pruning products and olive-oil cake, respectively. NDF values also decreased by 5%, 23%, 13% and 3% for, cottonwood, lentils straw, olive-oil cake and apple-tree pruning products respectively. Gamma irradiation (150 KGy) had no effects on ADF and ADL for lentils straw, apple-tree pruning products and olive-oil cake whereas, ADF decreased by 8.5% and ADL by 8.3 for cottonwood. Hemicellulose content increased by 12% for cottonwood while decreased by 54% for lentils straw and by 33% for apple-tree pruning products with no effects for olive-oil cake. Cellulose content decreased by 8.6% for cottonwood whereas no effects for the remaining residues were seen. Gamma irradiation treatment improved the nutritive value of the agriculture residues examined. The reduction in crude fibre content varies with the residue. (author). 15 refs., 5 tabs

Riparian Cottonwood Ecosystems and Regulated Flows in Kootenai and Yakima Sub-Basins : Volume I Kootenai River (Overview, Report and Appendices).

Energy Technology Data Exchange (ETDEWEB)

Jamieson, Bob; Braatne, Jeffrey H.

2001-10-01

Riparian vegetation and especially cottonwood and willow plant communities are dependent on normative flows and especially, spring freshette, to provide conditions for recruitment. These plant communities therefore share much in common with a range of fish species that require natural flow conditions to stimulate reproduction. We applied tools and techniques developed in other areas to assess riparian vegetation in two very different sub-basins within the Columbia Basin. Our objectives were to: Document the historic impact of human activity on alluvial floodplain areas in both sub-basins; Provide an analysis of the impacts of flow regulation on riparian vegetation in two systems with very different flow regulation systems; Demonstrate that altered spring flows will, in fact, result in recruitment to cottonwood stands, given other land uses impacts on each river and the limitations imposed by other flow requirements; and Assess the applicability of remote sensing tools for documenting the distribution and health of cottonwood stands and riparian vegetation that can be used in other sub-basins.

Paraffin dispersant application for cleaning subsea flow lines in the deep water Gulf of Mexico cottonwood development

Energy Technology Data Exchange (ETDEWEB)

Jennings, David; White, Jake; Pogoson, Oje [Baker Hughes Inc., Houston, TX (United States); Barros, Dalmo; Ramachandran, Kartik; Bonin, George; Waltrich, Paulo; Shecaira, Farid [PETROBRAS America, Houston, TX (United States); Ziglio, Claudio [Petroleo Brasileiro S.A. (CENPES/PETROBRAS), Rio de Janeiro, RJ (Brazil). Centro de Pesquisa e Desenvolvimento

2012-07-01

This paper discusses a paraffin dispersant (in seawater) application to clean paraffin deposition from a severely restricted 17.4-mile dual subsea flow line system in the Gulf of Mexico Cottonwood development. In principle, dispersant treatments are simple processes requiring effective dispersant packages and agitation to break-up and disperse deposition. Dispersants have been used onshore for treating wax deposition for decades. Implementation of a treatment in a long deep water production system, however, poses numerous challenges. The Cottonwood application was one of the first ever deep water dispersant applications. The application was designed in four separate phases: pre-treatment displacement for hydrate protection, dispersant treatment for paraffin deposition removal, pigging sequence for final flow line cleaning, and post-treatment displacement for hydrate protection. In addition, considerable job planning was performed to ensure the application was executed in a safe and environmentally responsible manner. Two dynamically positioned marine vessels were used for pumping fluids and capturing returns. The application was extremely successful in restoring the deep water flow lines back to near pre-production state. Final pigging operations confirmed the flow lines were cleaned of all restrictions. Significant paraffin deposition was removed in the application. Approximately 900 bbls of paraffin sludge was recovered from the 4000 bbl internal volume flow line loop. Furthermore, the application was completed with zero discharge of fluids. The application provided significant value for the Cottonwood development. It allowed production from wells to be brought on-line at a higher capacity, thereby generating increased revenue. It also allowed resumption of routine pigging operations. As such, the Cottonwood dispersant application illustrates that with proper planning and execution, paraffin dispersant treatments can be highly effective solutions for cleaning

Survival results of a biomass planting in the Missouri River floodplain

Science.gov (United States)

W. D. ' Dusty' Walter; John P. Dwyer

2003-01-01

A factor essential to successful tree planting in unprotected floodplain environments is survival. Two-year survival results from tree planting in an unprotected floodplain adjacent to the Missouri River are presented. Species planted included silver maple, locally collected cottonwood, and a superior cottonwood selection from Westvaco Corporation. Two spacings, 4 x 4...

Response of the Cottonwood Leaf Beetle (Coleoptera: Chrysomelidae) to Bacillus thuringiensis var. san diego

Science.gov (United States)

Leah S. Bauer

1990-01-01

A standardized laboratory bioassay was used to quantify the lethal and sub-lethal responses of larval and adult cottonwood leaf beetles, Chrysomela scripta F., to Bacillus thuringiensis var. san diego, formulated as M-One standard powder (Mycogen Corporation, San Diego). The median lethal concentration (LC

Decision Tree and Texture Analysis for Mapping Debris-Covered Glaciers in the Kangchenjunga Area, Eastern Himalaya

Directory of Open Access Journals (Sweden)

Adina Racoviteanu

2012-10-01

Full Text Available In this study we use visible, short-wave infrared and thermal Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER data validated with high-resolution Quickbird (QB and Worldview2 (WV2 for mapping debris cover in the eastern Himalaya using two independent approaches: (a a decision tree algorithm, and (b texture analysis. The decision tree algorithm was based on multi-spectral and topographic variables, such as band ratios, surface reflectance, kinetic temperature from ASTER bands 10 and 12, slope angle, and elevation. The decision tree algorithm resulted in 64 km2 classified as debris-covered ice, which represents 11% of the glacierized area. Overall, for ten glacier tongues in the Kangchenjunga area, there was an area difference of 16.2 km2 (25% between the ASTER and the QB areas, with mapping errors mainly due to clouds and shadows. Texture analysis techniques included co-occurrence measures, geostatistics and filtering in spatial/frequency domain. Debris cover had the highest variance of all terrain classes, highest entropy and lowest homogeneity compared to the other classes, for example a mean variance of 15.27 compared to 0 for clouds and 0.06 for clean ice. Results of the texture image for debris-covered areas were comparable with those from the decision tree algorithm, with 8% area difference between the two techniques.

76 FR 34197 - Anchorage; Change to Cottonwood Island Anchorage, Columbia River, Oregon and Washington

Science.gov (United States)

2011-06-13

... Cottonwood Island in the vicinity of the spoil area to approximately the Kalama North dock and the previous... litigation, eliminate ambiguity, and reduce burden. Protection of Children We have analyzed this proposed rule under Executive Order 13045, Protection of Children from Environmental Health Risks and Safety...

The Wall-Rock Record of Incremental Emplacement in the Little Cottonwood-Alta Magmatic and Hydrothermal System, Wasatch Mountains, Utah, U.S.A.

Science.gov (United States)

Stearns, M.; Callis, S.; Beno, C.; Bowman, J. R.; Bartley, J. M.

2017-12-01

Contact aureoles record the cumulative effects on wall rocks of magma emplacement. Like the plutons they surround, contact aureoles have long been regarded to form geologically instantaneously. Protracted incremental emplacement of plutons must be reconciled with the wall-rock record of heat and mass transfer. Fundamental questions include how heat and material move from intrusions into their aureoles and how long that process takes. The Little Cottonwood stock is surrounded by a 2 km-wide contact aureole that contains prograde AFM mineral assemblages in the pelitic layers of the Proterozoic Big Cottonwood Formation. The Alta stock is surrounded by a well characterized 1 km-wide contact aureole containing both prograde AFM and CMS mineral assemblages in Ophir Shale and Mississippian dolostones, respectively. Understanding the petrogenesis of these aureoles requires the timing of magmatism and wall-rock metamorphism to be independently determined. Preliminary petrochronology (U/Th-Pb dates and trace element concentrations collected by LASS-ICP-MS) from the inner aureoles of both intrusions establishes a protracted history of monazite (re)crystallization from 35-25 Ma in the Little Cottonwood aureole and 35 Ma in the Alta aureole. Little Cottonwood aureole monazites are characterized by a positive age correlation with heavy rare earth elements (HREE) and a negative correlation with Eu/Eu*. Alta aureole monazites have a similar range of the HREE concentrations and Eu/Eu* variation. Zircon growth interpreted to record emplacement-level magmatic crystallization of the western Little Cottonwood stock ranges from 33-28 Ma near the contact. Multi-grain U-Pb zircon TIMS dates from the Alta stock range from 35-33 Ma and are interpreted to suggest the full range of emplacement-level magmatism in the Alta stock. Additionally, in situ U-Pb titanite dates from the Alta stock record intermittent high temperature hydrothermal activity in the stock margin from 35-24 Ma. These new

Trees Containing Built-In Pulping Catalysts - Final Report - 08/18/1997 - 08/18/2000

Energy Technology Data Exchange (ETDEWEB)

Pullman, G.; Dimmel, D.; Peter, G.

2000-08-18

Several hardwood and softwood trees were analyzed for the presence of anthraquinone-type molecules. Low levels of anthraquinone (AQ) and anthrone components were detected using gas chromatography-mass spectroscopy and sensitive selected-ion monitoring techniques. Ten out of seventeen hardwood samples examined contained AQ-type components; however, the levels were typically below {approximately}6 ppm. No AQs were observed in the few softwood samples that were examined. The AQs were more concentrated in the heartwood of teak than in the sapwood. The delignification of pine was enhanced by the addition of teak chips ({approximately}0.7% AQ-equivalence content) to the cook, suggesting that endogenous AQs can be released from wood during pulping and can catalyze delignification reactions. Eastern cottonwood contained AQ, methyl AQ, and dimethyl AQ, all useful for wood pulping. This is the first time unsubstituted AQ has been observed in wood extracts. Due to the presence of these pulping catalysts, rapid growth rates in plantation settings, and the ease of genetic transformation, eastern cottonwood is a suitable candidate for genetic engineering studies to enhance AQ content. To achieve effective catalytic pulping activity, poplar and cottonwood, respectively, require {approximately}100 and 1000 times more for pulping catalysts. A strategy to increase AQ concentration in natural wood was developed and is currently being tested. This strategy involves ''turning up'' isochorismate synthase (ICS) through genetic engineering. Isochorismate synthase is the first enzyme in the AQ pathway branching from the shikimic acid pathway. In general, the level of enzyme activity at the first branch point or committed step controls the flux through a biosynthetic pathway. To test if the level of ICS regulates AQ biosynthesis in plant tissues, we proposed to over-express this synthase in plant cells. A partial cDNA encoding a putative ICS was available from the random

Survival and Growth of Cottonwood Clones After Angle Planting and Base Angle Treatments

Science.gov (United States)

W.K. Randall; Harvey E. Kennedy

1976-01-01

Presently, commercial cottonwood plantations in the lower Mississippi Valley are established using vertically planted, unrooted cuttings with a flat (90°) base. Neither survival nor first-year growth of a group of six Stoneville clones was improved by angle planting or cutting base angles diagonally. For one clone, survival was significantly better when base angle was...

Ecological structuring of yeasts associated with trees around Hamilton, Ontario, Canada.

Science.gov (United States)

Maganti, Harinad; Bartfai, David; Xu, Jianping

2012-02-01

This study seeks to determine the distribution and diversity of yeasts in and around the Hamilton area in Canada. In light of the increasing number of fungal infections along with rising morbidity and mortality rates, especially among the immunocompromised, understanding the diversity and distribution of yeasts in natural environments close to human habitations has become an increasingly relevant topic. In this study, we analyzed 1110 samples obtained from the hollows of trees, shrubs and avian droppings at 8 geographical sites in and around Hamilton, Ontario, Canada. A total of 88 positive yeast strains were isolated and identified belonging to 20 yeast species. Despite the relative proximity of the sampling sites, our DNA fingerprinting results showed that the yeast populations were highly heterogenous. Among the 14 tree species sampled, cedar, cottonwood and basswood hollows had relatively high yeast colonization rates. Interestingly, Candida parapsilosis was isolated almost exclusively from Pine trees only. Our results are consistent with microgeographic and ecological differentiation of yeast species in and around an urban environment. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Climatic data for the Cottonwood Lake area, Stutsman County, North Dakota 1982

Science.gov (United States)

Sturrock, A.M.; Hanson, B.A.; Scarborough, J.L.; Winter, T.C.

1986-01-01

Research on the hydrology of the Cottonwood Lake area, Stutsman County, North Dakota, includes study of evaporation. Presented here are those climatic data needed for energy-budget and mass-transfer evaporation studies, including: water-surface temperature, sediment temperature dry-bulb and wet-bulb air temperatures, vapor pressure at and above the water surface, wind speed, and short- and long-wave radiation. Data were collected at raft and land stations.

Climatic data for the Cottonwood Lake area, Stutsman County, North Dakota, 1983

Science.gov (United States)

Sturrock, A.M.; Hanson, B.A.; Scarborough, J.L.; Winter, T.C.

1987-01-01

Research on the hydrology of the Cottonwood Lake area, Stutsman County, North Dakota, includes study of evaporation. Climatic data needed for energy-budget and mass-transfer evaporation studies that were collected during 1983 include water-surface temperature, sediment temperature, dry-bulb and wet-bulb air temperature, vapor pressure at and above the water surface, wind speed, and short-and long-wave radiation. Data are collected at raft and land stations. (USGS)

Phreatophyte influence on reductive dechlorination in a shallow aquifer contaminated with trichloroethene (TCE)

Science.gov (United States)

Lee, R.W.; Jones, S.A.; Kuniansky, E.L.; Harvey, G.; Lollar, B.S.; Slater, G.F.

2000-01-01

Phytoremediation uses the natural ability of plants to degrade contaminants in groundwater. A field demonstration designed to remediate aerobic shallow groundwater contaminated with trichloroethene began in April 1996 with the planting of cottonwood trees, a short-rotation woody crop, over an approximately 0.2-ha area at the Naval Air Station, Fort Worth, Texas. The project was developed to demonstrate capture of contaminated groundwater and degradation of contaminants by phreatophytes. Analyses from samples of groundwater collected from July 1997 to June 1998 indicate that tree roots have the potential to create anaerobic conditions in the groundwater that will facilitate degradation of trichloroethene by microbially mediated reductive dechlorination. Organic matter from root exudates and decay of tree roots probably stimulate microbial activity, consuming dissolved oxygen. Dissolved oxygen concentrations, which varied across the site, were smallest near a mature cottonwood tree (about 20 years of age and 60 meters southwest of the cottonwood plantings) where degradation products of trichloroethene were measured. Oxidation of organic matter is the primary microbially mediated reaction occurring in the groundwater beneath the planted trees whereas near the mature cottonwood tree, data indicate that methanogenesis is the most probable reaction occurring. Reductive dechlorination in groundwater either is not occurring or is not a primary process away from the mature tree. Carbon-13 isotope values for trichloroethene are nearly identical at locations away from the mature tree, further confirming that dechlorination is not occurring at the site.

Eastern Redcedar Seedling Assessment

Data.gov (United States)

U.S. Environmental Protection Agency — Eastern redcedar tree seedling growth in response to various soil, nitrogen, and photosynthetic radiation characteristics. This dataset is associated with the...

Radial Growth and Physiological Response of Coniferous Trees to Arctic Amplification

Science.gov (United States)

Tei, Shunsuke; Sugimoto, Atsuko; Liang, Maochang; Yonenobu, Hitoshi; Matsuura, Yojiro; Osawa, Akira; Sato, Hisashi; Fujinuma, Junichi; Maximov, Trofim

2017-11-01

We describe the physiological responses of boreal conifers to climate change for the past 112 years using ring-width and carbon isotope ratio (δ13C) chronologies at six forest sites in northern Eurasia and Canada. Responses differed among regions, depending on their climatic and/or geographic characteristics. Tree radial growth decreased over the past 52 years in central eastern Siberia with the higher rate of summer temperature increase than other regions, as indicated by the negative correlation between radial growth and summer temperature, but increased in northern Europe and Canada. Changes in tree-ring δ13C indicated that recent climatic conditions have induced stronger drought stress for trees from central eastern Siberia than for those from other regions. The observed tree growth trends were compared to those simulated using a dynamic global vegetation model. Although the modeled annual net primary production (NPP) for trees generally exhibited similar decadal variation to radial growth, simulations did not show a recent decrease in tree growth, even in central eastern Siberia. This was probably due to an overestimation of the sensitivity of modeled tree NPP to precipitation. Our results suggest that the tree NPP forecasted under the expected future increases in temperature and average precipitation might be overestimated, especially in severely dry regions such as central eastern Siberia.

EAB induced tree mortality impacts ecosystem respiration and tree water use in an experimental forest

Science.gov (United States)

Charles E. Flower; Douglas J. Lynch; Kathleen S. Knight; Miquel A. Gonzales-Meler

2011-01-01

The invasive emerald ash borer (Agrilus planipennis Fairmaire, EAB) has been spreading across the forest landscape of the Midwest resulting in the rapid decline of ash trees (Fraxinus spp.). Ash trees represent a dominant riparian species in temperate deciduous forests of the Eastern United States (USDA FIA Database). Prior...

Analyzing tree cores to detect petroleum hydrocarbon-contaminated groundwater at a former landfill site in the community of Happy Valley-Goose Bay, eastern Canadian subarctic

DEFF Research Database (Denmark)

Fonkwe, Merline L D; Trapp, Stefan

2016-01-01

-gas chromatography-mass spectrometry. BTEX compounds were detected in tree cores, corroborating known groundwater contamination. A zone of anomalously high concentrations of total BTEX constituents was identified and recommended for monitoring by groundwater wells. Tree cores collected outside the landfill site......This research examines the feasibility of analyzing tree cores to detect benzene, toluene, ethylbenzene, and m, p, o-xylene (BTEX) compounds and methyl tertiary-butyl ether (MTBE) in groundwater in eastern Canada subarctic environments, using a former landfill site in the remote community of Happy...... Valley-Goose Bay, Labrador. Petroleum hydrocarbon contamination at the landfill site is the result of environmentally unsound pre-1990s disposal of households and industrial solid wastes. Tree cores were taken from trembling aspen, black spruce, and white birch and analyzed by headspace...

A practical alternative to single tree selection?

Science.gov (United States)

Gary W. Miller; H. Clay Smith

1993-01-01

When landowners want to develop and maintain an uneven-aged tree structure in eastern hardwood stands, single-tree selection often is suggested as the only advisable, long-term partial regeneration harvest method. Single-tree selection is preferred because it provides a means for improving quality and controlling stocking of the residual stand necessary for sustained...

Avian response to bottomland hardwood reforestation: the first 10 years

Science.gov (United States)

Twedt, D.J.; Wilson, R.R.; Henne-Kerr, J.L.; Grosshuesch, D.A.

2002-01-01

Bttomland hardwood forests were planted on agricultural fields in Mississippi and Louisiana using either predominantly Quercus species (oaks) or Populus deltoides (eastern cottonwood). We assessed avian colonization of these reforested sites between 2 and 10 years after planting. Rapid vertical growth of cottonwoods (circa 2 - 3 m / yr) resulted in sites with forest structure that supported greater species richness of breeding birds, increased Shannon diversity indices, and supported greater territory densities than on sites planted with slower-growing oak species. Grassland birds (Spiza americana [Dickcissel], and Sturnella magna [Eastern Meadowlark]) were indicative of species breeding on oak-dominated reforestation # 10 years old. Agelaius phoeniceus (Red-winged Blackbird) and Colinus virginianus (Northern Bobwhite) characterized cottonwood reforestation # 4 years old, whereas 14 species of shrub-scrub birds (e.g., Passerina cyanea [Indigo Bunting]) and early-successional forest birds (e.g., Vireo gilvus [Warbling Vireo]) typified cottonwood reforestation 5 to 9 years after planting. Rates of daily nest survival did not differ between reforestation strategies. Nest parasitism increased markedly in older cottonwood stands, but was overwhelmed by predation as a cause of nest failure. Based on Partners in Flight prioritization scores and territory densities, the value of cottonwood reforestation for avian conservation was significantly greater than that of oak reforestation during their first 10 years. Because of benefits conferred on breeding birds, we recommend reforestation of bottomland hardwoods include a high proportion of fast-growing, early successional species such as cottonwood.

Diagnosing injury to eastern forest trees

Science.gov (United States)

John M. Skelly; Donald D. Davis; William Merrill; E. Alan Cameron; H. Daniel Brown; David B. Drummond; Leon S., eds. Dochinger

1987-01-01

The purpose of this manual is to assist members of the National Vegetation Survey in recognizing air pollutant-induced injury and in identifying disease and insect damage that may be confused with air pollutant-induced injury to forest vegetation in the eastern United States. Ozone, sulfur dioxide, and, to a limited geographic extent, hydrogen fluoride, are all...

Oldman river dam mitigation program downstream vegetation project report, Volume II: The potential effects of an operating plan for the Oldman River dam on Riparian cottonwood forests

Energy Technology Data Exchange (ETDEWEB)

Mahoney, J.M.

1993-01-01

Extensive cottonwood (poplar) forests exist in the Oldman River valley downstream of the Oldman River dam. Studies of similar forests in nearby river valleys and elsewhere on the western prairies have found significant declines of some riparian forests following river damming. This investigation was initiated to determine the causes of cottonwood forest decline downstream from existing dams in southern Alberta; inventory the existing river valley forests in the Oldman Basin; establish study sites in the Oldman River forests to monitor changes in forest status following commissioning of the Oldman River dam, and evaluate the probable impact of proposed operating plans for the Oldman River dam and associated water control structures on downstream forests. This report summarizes the progress made in the analyses of the probable effects on the survival of the forests, including a discussion of the hydrological conditions essential for cottonwood forest regeneration and an explanation of the effects of altering these characteristics on riparian forests; the hydrological alterations expected along various river reaches in the Oldman Basin with the implementation of the proposed OD05 Oldman Dam operating plan; and preliminary analyses of the problem impacts of the OD05 operating plan on the cottonwood forests along these reaches.

Planting sentinel European trees in eastern Asia as a novel method to identify potential insect pest invaders.

Directory of Open Access Journals (Sweden)

Alain Roques

Full Text Available Quarantine measures to prevent insect invasions tend to focus on well-known pests but a large proportion of the recent invaders were not known to cause significant damage in their native range, or were not even known to science before their introduction. A novel method is proposed to detect new potential pests of woody plants in their region of origin before they are introduced to a new continent. Since Asia is currently considered to be the main supplier of insect invaders to Europe, sentinel trees were planted in China during 2007-2011 as an early warning tool to identify the potential for additional Asian insect species to colonize European trees. Seedlings (1-1.5 m tall of five broadleaved (Quercus petraea, Q. suber, Q. ilex, Fagus sylvatica, and Carpinus betulus and two conifer species (Abies alba and Cupressus sempervirens were planted in blocks of 100 seedlings at two widely separated sites (one in a nursery near Beijing and the other in a forest environment near Fuyang in eastern China, and then regularly surveyed for colonization by insects. A total of 104 insect species, mostly defoliators, were observed on these new hosts, and at least six species were capable of larval development. Although a number of the insects observed were probably incidental feeders, 38 species had more than five colonization events, mostly infesting Q. petraea, and could be considered as being capable of switching to European trees if introduced to Europe. Three years was shown to be an appropriate duration for the experiment, since the rate of colonization then tended to plateau. A majority of the identified species appeared to have switched from agricultural crops and fruit trees rather than from forest trees. Although these results are promising, the method is not appropriate for xylophagous pests and other groups developing on larger trees. Apart from the logistical problems, the identification to species level of the specimens collected was a major

Planting sentinel European trees in eastern Asia as a novel method to identify potential insect pest invaders.

Science.gov (United States)

Roques, Alain; Fan, Jian-Ting; Courtial, Béatrice; Zhang, Yan-Zhuo; Yart, Annie; Auger-Rozenberg, Marie-Anne; Denux, Olivier; Kenis, Marc; Baker, Richard; Sun, Jiang-Hua

2015-01-01

Quarantine measures to prevent insect invasions tend to focus on well-known pests but a large proportion of the recent invaders were not known to cause significant damage in their native range, or were not even known to science before their introduction. A novel method is proposed to detect new potential pests of woody plants in their region of origin before they are introduced to a new continent. Since Asia is currently considered to be the main supplier of insect invaders to Europe, sentinel trees were planted in China during 2007-2011 as an early warning tool to identify the potential for additional Asian insect species to colonize European trees. Seedlings (1-1.5 m tall) of five broadleaved (Quercus petraea, Q. suber, Q. ilex, Fagus sylvatica, and Carpinus betulus) and two conifer species (Abies alba and Cupressus sempervirens) were planted in blocks of 100 seedlings at two widely separated sites (one in a nursery near Beijing and the other in a forest environment near Fuyang in eastern China), and then regularly surveyed for colonization by insects. A total of 104 insect species, mostly defoliators, were observed on these new hosts, and at least six species were capable of larval development. Although a number of the insects observed were probably incidental feeders, 38 species had more than five colonization events, mostly infesting Q. petraea, and could be considered as being capable of switching to European trees if introduced to Europe. Three years was shown to be an appropriate duration for the experiment, since the rate of colonization then tended to plateau. A majority of the identified species appeared to have switched from agricultural crops and fruit trees rather than from forest trees. Although these results are promising, the method is not appropriate for xylophagous pests and other groups developing on larger trees. Apart from the logistical problems, the identification to species level of the specimens collected was a major difficulty. This

Segregating the Effects of Seed Traits and Common Ancestry of Hardwood Trees on Eastern Gray Squirrel Foraging Decisions.

Science.gov (United States)

Sundaram, Mekala; Willoughby, Janna R; Lichti, Nathanael I; Steele, Michael A; Swihart, Robert K

2015-01-01

The evolution of specific seed traits in scatter-hoarded tree species often has been attributed to granivore foraging behavior. However, the degree to which foraging investments and seed traits correlate with phylogenetic relationships among trees remains unexplored. We presented seeds of 23 different hardwood tree species (families Betulaceae, Fagaceae, Juglandaceae) to eastern gray squirrels (Sciurus carolinensis), and measured the time and distance travelled by squirrels that consumed or cached each seed. We estimated 11 physical and chemical seed traits for each species, and the phylogenetic relationships between the 23 hardwood trees. Variance partitioning revealed that considerable variation in foraging investment was attributable to seed traits alone (27-73%), and combined effects of seed traits and phylogeny of hardwood trees (5-55%). A phylogenetic PCA (pPCA) on seed traits and tree phylogeny resulted in 2 "global" axes of traits that were phylogenetically autocorrelated at the family and genus level and a third "local" axis in which traits were not phylogenetically autocorrelated. Collectively, these axes explained 30-76% of the variation in squirrel foraging investments. The first global pPCA axis, which produced large scores for seed species with thin shells, low lipid and high carbohydrate content, was negatively related to time to consume and cache seeds and travel distance to cache. The second global pPCA axis, which produced large scores for seeds with high protein, low tannin and low dormancy levels, was an important predictor of consumption time only. The local pPCA axis primarily reflected kernel mass. Although it explained only 12% of the variation in trait space and was not autocorrelated among phylogenetic clades, the local axis was related to all four squirrel foraging investments. Squirrel foraging behaviors are influenced by a combination of phylogenetically conserved and more evolutionarily labile seed traits that is consistent with a weak

Quality index tables for some eastern hardwood species

Science.gov (United States)

Joseph J. Mendel; William H. Smith; William H. Smith

1970-01-01

This paper briefly reviews the quality-index concept, presents log-quality index tables for a selected group of eastern hardwood tree species, and explains how timber operators can use Q.I. for evaluating the lumber that can be sawed from logs and trees.

The EASTNET Project: Extending the Network of Climate-Sensitive Tree-Ring Chronologies From the Eastern United States for Reconstructing the Spatio-Temporal Characteristics of Climate and Drought Over the Past Millennium

Science.gov (United States)

Buckley, B. M.; Cook, E. R.

2002-12-01

Recently, a network of gridded PDSI reconstructions for the contiguous United States was produced, based on the available network of drought-sensitive tree-ring chronologies (Cook et al. 1999). Analyses were constrained to the common period of 1700 - 1979 due to the limitations of the available tree-ring data. While several chronologies from the western U.S. span 1,000 years or more, very few chronologies from the eastern U.S. covered even the past 500 years. The objective of this project, funded by the National Science Foundation's ESH program, is to extend the tree-ring chronology network from the eastern U.S. with chronologies spanning the past 500-1,000 years. This aim is being achieved by sampling in areas that have escaped the effects of development, logging and major disturbance such as fire. The two main target species are Thuja occidentalis (eastern white cedar) and Juniperus virginiana (eastern red cedar). The primary terrain types are on cliffs, rocky outcrops, and other areas that have been difficult to access. We have already developed chronologies from Wisconsin, New Hampshire, Pennsylvania, West Virginia, and Virginia that span from 500 to 1500 years. The temporal depth of these chronologies is being extended through the exploitation of "sub-fossil" wood found at these sites, in the form of standing-dead stems and downed and buried logs. We are also currently pursuing leads in Maine, Vermont, Massachusetts, Connecticut, New York, New Jersey Pennsylvania, Kentucky and North Carolina where old cedar trees have either been reported or where terrain types match criteria developed for this project. In this paper we discuss the current status of the network, and explore the spatio-temporal characteristics of climate and drought across the eastern US for the past 500 years and more. We use our preliminary network to explore the regional expression of climate anomalies such as drought. Our analyses so far demonstrates multicentennial variability suggestive

Potential effects of climate change on streamflow for seven watersheds in eastern and central Montana

Directory of Open Access Journals (Sweden)

Katherine J. Chase

2016-09-01

New hydrological insights for the region: Projected changes in mean annual and mean monthly streamflow vary by the RegCM3 model selected, by watershed, and by future period. Mean annual streamflows for all future periods are projected to increase (11–21% for two of the four central Montana watersheds: Middle Musselshell River and Cottonwood Creek. Mean annual streamflows for all future periods are projected to decrease (changes of −24 to −75% for Redwater River watershed in eastern Montana. Mean annual streamflows are projected to increase slightly (2–15% for the 2030 period and decrease (changes of −16 to −44% for the 2080 period for the four remaining watersheds.

Molecular and optical properties of tree-derived dissolved organic matter in throughfall and stemflow from live oaks and eastern red cedar

Science.gov (United States)

Stubbins, Aron; Silva, Leticia M.; Dittmar, Thorsten; Van Stan, John T.

2017-03-01

Studies of dissolved organic matter (DOM) transport through terrestrial aquatic systems usually start at the stream. However, the interception of rainwater by vegetation marks the beginning of the terrestrial hydrological cycle making trees the headwaters of aquatic carbon cycling. Rainwater interacts with trees picking up tree-DOM, which is then exported from the tree in stemflow and throughfall. Stemflow denotes water flowing down the tree trunk, while throughfall is the water that drips through the leaves of the canopy. We report the concentrations, optical properties (light absorbance) and molecular signatures (ultrahigh resolution mass spectrometry) of tree-DOM in throughfall and stemflow from two tree species (live oak and eastern red cedar) with varying epiphyte cover on Skidaway Island, Savannah, Georgia, USA. Both stemflow and throughfall were enriched in DOM compared to rainwater, indicating trees were a significant source of DOM. The optical and molecular properties of tree-DOM were broadly consistent with those of DOM in other aquatic ecosystems. Stemflow was enriched in highly colored DOM compared to throughfall. Elemental formulas identified clustered the samples into three groups: oak stemflow, oak throughfall and cedar. The molecular properties of each cluster are consistent with an autochthonous aromatic-rich source associated with the trees, their epiphytes and the microhabitats they support. Elemental formulas enriched in oak stemflow were more diverse, enriched in aromatic formulas, and of higher molecular mass than for other tree-DOM classes, suggesting greater contributions from fresh and partially modified plant-derived organics. Oak throughfall was enriched in lower molecular weight, aliphatic and sugar formulas, suggesting greater contributions from foliar surfaces. While the optical properties and the majority of the elemental formulas within tree-DOM were consistent with vascular plant-derived organics, condensed aromatic formulas were

Influence of water table decline on growth allocation and endogenous gibberellins in black cottonwood

Energy Technology Data Exchange (ETDEWEB)

Rood, S.B.; Zanewich, K.; Stefura, C. [Lethbridge Univ., Lethbridge, AB (Canada). Dept. of Biological Sciences; Mahoney, J.M. [Alberta Environmental Protection, Lethbridge, AB (Canada)

2000-06-01

Cottonwoods have shown an adaptation to the riparian zone by coordinating root elongation to maintain contact with the water table, whose depth varies with the elevation of the adjacent river. The rate of water decline on growth allocation and concentrations of endogenous gibberellins (GAs) in black cottonwood saplings were studied at the University of Lethbridge, Alberta. Water declines were achieved by using rhizopods, and root elongation approximately doubled in response whereas leaf area was reduced. At some point, a greater water decline rate led to water stress resulting in reduced growth, increased leaf diffusive resistance, decreased water potential, and leaf senescence and abscission. After extraction of endogenous GAs, they were purified and analysed by gas chromatography-selected ion monitoring with internal ({sup 2}H{sub 2})GA standards. The results showed that GAs were higher in shoot tips and sequentially lower in basal stems, root tips, leaves and upper roots. Noticeable relationships did not appear between GA concentration and growth allocation across the water decline treatments. Only GA{sub 8} showed a consistent reduction in plants experiencing water table decline. This research did not permit the authors to conclude whether endogenous GAs play a primary role in the regulation of root elongation in response to water table decline. 7 figs., 25 refs.

Influences of eastern hemlock mortality on nutrient cycling

Science.gov (United States)

Thad E. Yorks; Jennifer C. Jenkins; Donald J. Leopold; Dudley J. Raynal; David A. Orwig

2000-01-01

Mortality of eastern hemlock (Tsuga canadensis (L.) Carriere) may be caused by a variety of agents, but hemlock trees of all sizes over a large geographic area are currently threatened by an outbreak of the hemlock woolly adelgid (HWA: Adelges tsugae Annand) in the eastern United States. In this paper, we review what is currently...

Pentimento: Fuels reduction and restoration in the Bosque of the Middle Rio Grande

Science.gov (United States)

Deborah M. Finch

2008-01-01

The Middle Rio Grande of New Mexico is the most extensive, remaining bosque, or cottonwood forest in the southwest. Alterations caused by humans-damming and channeling the river, controlling floods, and planting non-native trees-have disrupted the cycles of the earlier ecosystem. Without periodic flooding, native cottonwoods cannot regenerate. Invasive exotic plants...

Lower Mississippi River Environmental Program. Report 2. A Physical Description of Main Stem Levee Borrow Pits along the Lower Mississippi River

Science.gov (United States)

1988-02-01

Eastern cottonwood, green ash, sugarberry. box elder, bald cypress, willow honey locust, slippery elm , overcup oak and bitter pecan. Principle...vines and understory. Woody vegetation surrounds the borrow pit and consists of American and slippery elms , silver maple, black willow, cottonwood, pin...aquatica Water elm Ulmus rubra Slippery elm Urtica dioica Stinging nettle Vaccinium sp. Blueberry Vaccinium spp. Vaccinum Vernonia altissima Ironweed

Anthracnose Diseases of Eastern Hardwoods

Science.gov (United States)

Frederick H. Berry

1985-01-01

Anthracnose diseases of hardwood trees are widespread throughout the Eastern United States. The most common symptom of these diseases is dead areas or blotches on the leaves. Because of the brown and black, scorched appearance of the leaves, the diseases are sometimes called leaf blight.

Growth response of four species of Eastern hardwood tree seedlings exposed to ozone, acidic precipitation, and sulfur dioxide

International Nuclear Information System (INIS)

Davis, D.D. Skelly, J.M.

1992-01-01

In 1987 a study was conducted in controlled environment chambers to determine the foliar sensitivity of tree seedlings of eight species to ozone and acidic precipitation, and to determine the influence of leaf position on symptom severity. Jensen and Dochinger conducted concurrent similar studies in Continuously Stirred Tank Reactor (CSTR) chambers with ten species of forest trees. Based on the results of these initial studies, four species representing a range in foliar sensitivity to ozone were chosen: black cherry (Prunus serotina Ehrh.), red maple (Acer rubrum L.), northern red oak (Quercus rubra L.) and yellow-poplar (Liriodendron tulipifera L.). These species were also chosen because of their ecological and/or commercial importance in Pennsylvania. Seedlings were exposed in growth chambers simulated acid rain. In addition acute exposures to sulfur dioxide were conducted in a regime based on unpublished monitoring data collected near coal-fired power plants. The objective of this study was to determine if the pollutant treatments influenced the growth and productivity of seedlings of these four species. This information will help researchers and foresters understand the role of air pollution in productivity of eastern forests

Analyzing tree cores to detect petroleum hydrocarbon-contaminated groundwater at a former landfill site in the community of Happy Valley-Goose Bay, eastern Canadian subarctic.

Science.gov (United States)

Fonkwe, Merline L D; Trapp, Stefan

2016-08-01

This research examines the feasibility of analyzing tree cores to detect benzene, toluene, ethylbenzene, and m, p, o-xylene (BTEX) compounds and methyl tertiary-butyl ether (MTBE) in groundwater in eastern Canada subarctic environments, using a former landfill site in the remote community of Happy Valley-Goose Bay, Labrador. Petroleum hydrocarbon contamination at the landfill site is the result of environmentally unsound pre-1990s disposal of households and industrial solid wastes. Tree cores were taken from trembling aspen, black spruce, and white birch and analyzed by headspace-gas chromatography-mass spectrometry. BTEX compounds were detected in tree cores, corroborating known groundwater contamination. A zone of anomalously high concentrations of total BTEX constituents was identified and recommended for monitoring by groundwater wells. Tree cores collected outside the landfill site at a local control area suggest the migration of contaminants off-site. Tree species exhibit different concentrations of BTEX constituents, indicating selective uptake and accumulation. Toluene in wood exhibited the highest concentrations, which may also be due to endogenous production. Meanwhile, MTBE was not found in the tree cores and is considered to be absent in the groundwater. The results demonstrate that tree-core analysis can be useful for detecting anomalous concentrations of petroleum hydrocarbons, such as BTEX compounds, in subarctic sites with shallow unconfined aquifers and permeable soils. This method can therefore aid in the proper management of contamination during landfill operations and after site closures.

Maintenance of eastern hemlock forests: Factors associated with hemlock vulnerability to hemlock woolly adelgid

Science.gov (United States)

Mary Ann Fajvan; Petra Bohall Wood

2010-01-01

Eastern hemlock (Tsuga canadensis [L.]) is the most shade-tolerant and long-lived tree species in eastern North America. The hemlock woolly adelgid (Adelges tsugae) (HWA), is a nonnative invasive insect that feeds on eastern hemlock and Carolina hemlock (Tsuga caroliniana Engelm.). HWA currently is established in...

Regional difference of the start time of the recent warming in Eastern China: prompted by a 165-year temperature record deduced from tree rings in the Dabie Mountains

Science.gov (United States)

Cai, Qiufang; Liu, Yu; Duan, Bingchuang; Sun, Changfeng

2018-03-01

Tree-ring studies from tropical to subtropical regions are rarer than that from extratropical regions, which greatly limit our understanding of some critical climate change issues. Based on the tree-ring-width chronology of samples collected from the Dabie Mountains, we reconstructed the April-June mean temperature for this region with an explained variance of 46.8%. Five cold (1861-1869, 1889-1899, 1913-1920, 1936-1942 and 1952-1990) and three warm (1870-1888, 1922-1934 and 2000-2005) periods were identified in the reconstruction. The reconstruction not only agreed well with the instrumental records in and around the study area, but also showed good resemblance to previous temperature reconstructions from nearby regions, indicating its spatial and temporal representativeness of the temperature variation in the central part of eastern China. Although no secular warming trend was found, the warming trend since 1970 was unambiguous in the Dabie Mountains (0.064 °C/year). Further temperature comparison indicated that the start time of the recent warming in eastern China was regional different. It delayed gradually from north to south, starting at least around 1940 AD in the north part, around 1970 AD in the central part and around 1980s in the south part. This work enriches the high-resolution temperature reconstructions in eastern China. We expect that climate warming in the future would promote the radial growth of alpine Pinus taiwanensis in the subtropical areas of China, therefore promote the carbon capture and carbon storage in the Pinus taiwanensis forest. It also helps to clarify the regional characteristic of recent warming in eastern China.

Distribution and Abundance of Adelges tsugae (Hemiptera: Adelgidae) Within Hemlock Trees

Science.gov (United States)

S.V. Joseph; J.L. Hanula; S.K. Braman

2011-01-01

We studied the distribution of hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), within hemlock trees for three summer (progrediens) and two winter (sistens) generations in northern Georgia. Eastern hemlock, Tsuga canadensis (L.) Carrie` re, trees were treated with 0, 10, or 25% of 1.5 g of imidacloprid per 2.5 cm of tree diameter at breast height...

A history of tree planting in West Virginia

Science.gov (United States)

Kenneth L. Carvell

2012-01-01

West Virginia has often been described by botanists as “the most southern of the northern states, the most northern of the southern states, the most eastern of the western states, and the most western of the eastern states." Truly, West Virginia, "the Mountain State," is the cross roads for many species of trees and herbaceous vegetation, and even today...

Certainty of paternity and paternal investment in eastern bluebirds and tree swallows

Science.gov (United States)

Kempenaers, Bart; Lanctot, Richard B.; Robertson, Raleigh J.

1998-01-01

Extra-pair paternity is common in many socially monogamous passerine birds with biparental care. Thus, males often invest in offspring to which they are not related. Models of optimal parental investment predict that, under certain assumptions, males should lower their investment in response to reduced certainty of paternity. We attempted to reduce certainty of paternity experimentally in two species, the eastern bluebird, Sialia sialis, and the tree swallow, Tachycineta bicolor, by temporarily removing fertile females on two mornings during egg laying. In both species, experimental males usually attempted to copulate with the female immediately after her reappearance, suggesting that they experienced the absence of their mate as a threat to their paternity. Experimental males copulated at a significantly higher rate than control males. However, contrary to the prediction of the model, experimental males did not invest less than control males in their offspring. There was no difference between experimental and control nests in the proportion of male feeds, male and female feeding rates, nestling growth and nestling condition and size at age 14 days. We argue that females might have restored the males’ confidence in paternity after the experiment by soliciting or accepting copulations. Alternatively, males may not reduce their effort, because the fitness costs to their own offspring may outweigh the benefits for the males, at least in populations where females cannot fully compensate for reduced male investment.

Resistance of eastern hardwood stems to fire injury and damage

Science.gov (United States)

Kevin T. Smith; Elaine Kennedy Sutherland

2006-01-01

This paper reviews the protective features and defensive responses of eastern hardwood species exposed to fire. Trees survive fire through protective features such as thick bark and the induced defenses of compartmentalization. Dissection of trees exposed to prescribed fire in an oak forest in southern Ohio highlights the need to distinguish between bark scorch, stem...

North End Runway Material Extraction and Transport Environmental Assessment

Science.gov (United States)

2006-05-01

raspberry, currant, bunchberry, horsetail, and high bush cranberry as well as willow, elderberry, rusty menzeiseia, devil’s club, and sapling cottonwood...shrubs and young trees to include paper birch, willow, aspen, cottonwood/balsam poplar, high bush cranberry , Sitka alder, and mountain ash. In winter...the southeast corner of the plot. Standing water appears in small depressions around the vegetated area as well. Vegetation: Table 1, below

From rubber tree homeland to rubber tree plantation: Jacques Huber and his studies on the culture of heveas in the East (1911-1912

Directory of Open Access Journals (Sweden)

Anna Raquel de Matos Castro

2009-12-01

Full Text Available The paper deals with the trip of the Swiss botanist Jacques Huber (1867-1914 to the main eastern rubber producing countries between 1911 and 1912. This trip was intended to develop studies on the cultivation of Hevea brasiliensis in that region. Huber was commissioned with the task by the State of Pará governor João Coelho, who wanted to find solutions to the downfall of the regional economy. The economy of Amazonia was primarily based on rubber extractivism and was seriously endangered due the market controlled by England from eastern plantations. Back to Brazil, Huber published a report with information about the society, economy and environment where the rubber trees were cultivated. The report compiles scientific observations and the topics that motivated the regional elites in that context. In addition to the brief analyses of the report, photographs took by Huber in the East of rubber trees plantations, tree tapping and local workers are published.

The effect of acid precipitation on tree growth in eastern North America

Science.gov (United States)

Charles V. Cogbill

1976-01-01

Detailed study of the history of forest tree growth by tree-ring analysis is used to assess the effect of acid precipitation. The pattern and historical trends of acid precipitation deposition are compared with growth trends from mature forest stands in New Hampshire and Tennessee. No clear indication of a regional, synchronized decrease in tree growth was found. The...

Development of Envelope Curves for Predicting Void Dimensions from Overturned Trees

Science.gov (United States)

2014-07-01

Engineers Washington , DC 20314-1000 ERDC/GSL TR-14-27 ii Abstract To evaluate the potential influence of a tree on embankment stability, it is...4.5 Consistent influence of tree diameter and species on damage in nine eastern North America tornado blowdowns (Peterson 2007...likely to be blown down than deciduous trees . Phillips et al. (2008) independently came to the same conclusion that conifers have a higher

Flooding Regime Impacts on Radiation, Evapotranspiration, and Latent Energy Fluxes over Groundwater-Dependent Riparian Cottonwood and Saltcedar Forests

Directory of Open Access Journals (Sweden)

James Cleverly

2015-01-01

Full Text Available Radiation and energy balances are key drivers of ecosystem water and carbon cycling. This study reports on ten years of eddy covariance measurements over groundwater-dependent ecosystems (GDEs in New Mexico, USA, to compare the role of drought and flooding on radiation, water, and energy budgets of forests differing in species composition (native cottonwood versus nonnative saltcedar and flooding regime. After net radiation (700–800 W m−2, latent heat flux was the largest energy flux, with annual values of evapotranspiration exceeding annual precipitation by 250–600%. Evaporative cooling dominated the energy fluxes of both forest types, although cottonwood generated much lower daily values of sensible heat flux (<−5 MJ m−2 d−1. Drought caused a reduction in evaporative cooling, especially in the saltcedar sites where evapotranspiration was also reduced, but without a substantial decline in depth-to-groundwater. Our findings have broad implications on water security and the management of native and nonnative vegetation within semiarid southwestern North America. Specifically, consideration of the energy budgets of GDEs as they respond to fluctuations in climatic conditions can inform the management options for reducing evapotranspiration and maintaining in-stream flow, which is legally mandated as part of interstate and international water resources agreements.

Tree growth and vegetation activity at the ecosystem-scale in the eastern Mediterranean

Science.gov (United States)

Coulthard, Bethany L.; Touchan, Ramzi; Anchukaitis, Kevin J.; Meko, David M.; Sivrikaya, Fatih

2017-08-01

Linking annual tree growth with remotely-sensed terrestrial vegetation indices provides a basis for using tree rings as proxies for ecosystem primary productivity over large spatial and long temporal scales. In contrast with most previous tree ring/remote sensing studies that have focused on temperature-limited boreal and taiga environments, here we compare the normalized difference vegetation index (NDVI) with a network of Pinus brutia tree ring width chronologies collected along ecological gradients in semiarid Cyprus, where both radial tree growth and broader vegetation activity are controlled by drought. We find that the interaction between precipitation, elevation, and land-cover type generate a relationship between radial tree growth and NDVI. While tree ring chronologies at higher-elevation forested sites do not exhibit climate-driven linkages with NDVI, chronologies at lower-elevation dry sites are strongly correlated with NDVI during the winter precipitation season. At lower-elevation sites, land cover is dominated by grasslands and shrublands and tree ring widths operate as a proxy for ecosystem-scale vegetation activity. Tree rings can therefore be used to reconstruct productivity in water-limited grasslands and shrublands, where future drought stress is expected to alter the global carbon cycle, biodiversity, and ecosystem functioning in the 21st century.

Red-cockaded woodpecker cavity tree resin avoidance by southern flying squirrels

Science.gov (United States)

Richard R. Schaefer; Daniel Saenz

1998-01-01

While examining red-cockaded woodpecker (Picoides borealis) cavity contents in eastern Texas, the authors observed cavity tree resin avoidance by southern flying squirrels (Glaucomys volans). The tree surface around an active red-cockaded woodpecker cavity is coated with sticky resin which flows from resin wells created by the woodpecker. The southern flying squirrel...

Influence of Imidacloprid and Horticultural Oil on Spider Abundance on Eastern Hemlock in the Southern Appalachians.

Science.gov (United States)

Hakeem, A; Grant, J F; Lambdin, P L; Hale, F A; Rhea, J R; Wiggins, G J; Coots, C

2018-05-08

Hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), is an exotic pest of eastern hemlock, Tsuga canadensis (L.) Carrière (Pinales: Pinaceae), in the eastern United States. Two commonly used insecticides to manage adelgid are imidacloprid, a systemic neonicotinoid insecticide, and horticultural oil, a refined petroleum oil foliar spray. We have investigated the influence of imidacloprid and horticultural oil on spider abundance at different canopy strata in eastern hemlock. In total, 2,084 spiders representing 11 families were collected from the canopies of eastern hemlock. In beat-sheet and direct observation samples, the families Theridiidae, Araneidae, Salticidae, and Anyphaenidae were the most abundant. Significantly higher numbers of spiders were recorded on untreated control trees compared with trees treated with imidacloprid using soil drench and soil injection applications. Spider abundance in trees injected with imidacloprid and horticultural oil applications did not significantly differ from control trees. Spider abundance was significantly greater in the top and middle strata of the canopy than in the bottom stratum, where imidacloprid concentrations were the highest. Regression analysis showed that spider abundance was inversely associated with imidacloprid concentration. This research demonstrates that imidacloprid, when applied with selected methods, has the potential to result in reductions of spider densities at different strata. However, slight reductions in spider abundance may be an acceptable short-term ecological impact compared with the loss of an untreated hemlock and all the associated ecological benefits that it provides. Future studies should include investigations of long-term impact of imidacloprid on spiders associated with eastern hemlock.

Increasing tree cover in degrading landscapes

DEFF Research Database (Denmark)

Rahman, Syed Ajijur; Rahman, Md Faizar; Sunderland, Terry

2014-01-01

-functionality’. Two agroforestry models suitable for adoption by farmers have been identified. Multi-strata agroforestry, based on a fruit and timber tree canopy with vegetables and tuber species in the understorey, can be practiced in the shifting cultivation fields near settlements. Fruit and timber tree......Research was conducted in Alutilla Valley in eastern Bangladesh to identify the nature of existing agroforestry systems and to identify potential agroforestry models that could ameliorate currently degrading forest resources Data were collected through farmer participatory research and a structured......-based conservation agroforestry is well suited to manage large-scale biologically depleted landscapes. Both systems yield early financial returns, facilitating the change from shifting cultivation to multi-strata agroforestry or fruit and tree-based conservation agroforestry....

Using dendrochronology to model hemlock woolly adelgid effects on eastern hemlock growth and vulnerability

Science.gov (United States)

James Rentch; Mary Ann Fajvan; Richard Evans; Brad. Onken

2008-01-01

This study examined the relationship between eastern hemlock (Tsuga canadensis (L.) Carr.) crown condition and changes in radial growth associated with infestation by hemlock woolly adelgid (HWA), Adelges tsugae (Hemiptera: Adelgidae). Tree-ring chronologies of eastern hemlock were used to develop a binomial decline index based on...

Lichen flora and ecology of the roadside trees

Energy Technology Data Exchange (ETDEWEB)

Rydzak, J

1972-01-01

Investigations of the lichen flora of roadside trees were carried out at 69 sites in eastern Poland in 1966-1969. Conclusive relationships between lichen distributions and air pollution from automobile exhaust gases could not be inferred from the data.

Tree migration detection through comparisons of historic and current forest inventories

Science.gov (United States)

Christopher W. Woodall; Christopher M. Oswalt; James A. Westfall; Charles H. Perry; Mark N. Nelson

2009-01-01

Changes in tree species distributions are a potential impact of climate change on forest ecosystems. The examination of tree species shifts in forests of the eastern United States largely has been limited to modeling activities with little empirical analysis of long-term forest inventory datasets. The goal of this study was to compare historic and current spatial...

Spatial and temporal distribution of 14C in cellulose in tree rings in Central and Eastern Canada: comparison with long-term atmospheric and environmental data

International Nuclear Information System (INIS)

Kotzer, T.G.; Watson, W.L.

1999-05-01

Dendrochronologically characterized tree rings from several different species across Central and Eastern Canada and spanning a time range of several decades have been analysed for their 14 C specific activities using oxygen combustion - direct liquid scintillation counting techniques. Carbon-14 specific activities varied between 218 and 439 Bq·kg -1 (±5 to 10%) and yielded a good correlation with the 14 C measured in long-term records of 14 C-in-air values, although 14 C levels in Canada are slightly higher (10 to 20 per mil). An average pre-bomb 14 C value of 225 Bq·kg -1 was obtained from tree rings between 1910 and 1945 which agrees with the value for NBS oxalic acid standard for 'modern' 14 C at 226 Bq·kg -1 . Present-day levels of 14 C in the tree rings are on the order of 250 Bq·kg -1 , indicating that they, like 14 C0 2 -in-air values, have yet to reach 'pre-nuclear testing' levels. Specific activities of 14 C in tree rings from several sites in Canada show no systematic changes with respect to their distance from CANDU heavy-water nuclear power generating stations, suggesting that these stations have had negligible effects on the atmospheric radiocarbon budget for mid-latitudinal North America. The radiocarbon data from the tree rings indicate that atmospheric 14 C has an atmospheric half-time on the order of approximately 15 years, similar to that from other data sets. (author)

Abundance of juvenile eastern box turtles in manages forest stands

Science.gov (United States)

Z. Felix; Y. Wang; H. Czech; C. Schweitzer

2008-01-01

Between 2002 and 2005, we used drift fences and artificial pools to sample juvenile eastern box turtles (Terrapene carolina) in northeastern Alabama in forest stands experimentally treated to retain various amounts of overstory trees—clear-cuts and those with 25%–50% and 75%–100% of trees retained.We captured juvenile turtles only in clear-cut and 25%–50% retention...

Screening and Testing Phytochemicals in Eastern Redcedar (Juniperus virginiana) for Development of Potential Entrepreneurial Opportunities

Science.gov (United States)

Eastern redcedar (Juniperus virginiana) is often considered a “trash or nuisance” tree. In some states, this species has been declared invasive and management strategies have been adopted to destroy it. However, value-added phytochemical products from eastern redcedar have the potential to create n...

Post-glacial phylogeography and evolution of a wide-ranging highly-exploited keystone forest tree, eastern white pine (Pinus strobus) in North America: single refugium, multiple routes.

Science.gov (United States)

Zinck, John W R; Rajora, Om P

2016-03-02

Knowledge of the historical distribution and postglacial phylogeography and evolution of a species is important to better understand its current distribution and population structure and potential fate in the future, especially under climate change conditions, and conservation of its genetic resources. We have addressed this issue in a wide-ranging and heavily exploited keystone forest tree species of eastern North America, eastern white pine (Pinus strobus). We examined the range-wide population genetic structure, tested various hypothetical population history and evolutionary scenarios and inferred the location of glacial refugium and post-glacial recolonization routes. Our hypothesis was that eastern white pine survived in a single glacial refugium and expanded through multiple post-glacial recolonization routes. We studied the range-wide genetic diversity and population structure of 33 eastern white pine populations using 12 nuclear and 3 chloroplast microsatellite DNA markers. We used Approximate Bayesian Computation approach to test various evolutionary scenarios. We observed high levels of genetic diversity, and significant genetic differentiation (F ST = 0.104) and population structure among eastern white pine populations across its range. A south to north trend of declining genetic diversity existed, consistent with repeated founder effects during post-glaciation migration northwards. We observed broad consensus from nuclear and chloroplast genetic markers supporting the presence of two main post-glacial recolonization routes that originated from a single southern refugium in the mid-Atlantic plain. One route gave rise to populations at the western margin of the species' range in Minnesota and western Ontario. The second route gave rise to central-eastern populations, which branched into two subgroups: central and eastern. We observed minimal sharing of chloroplast haplotypes between recolonization routes but there was evidence of admixture between the

Host tree resistance against the polyphagous

Science.gov (United States)

W. D. Morewood; K. Hoover; P. R. Neiner; J.R. McNeil; J. C. Sellmer

2004-01-01

Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae: Lamiini) is an invasive wood-boring beetle with an unusually broad host range and a proven ability to increase its host range as it colonizes new areas and encounters new tree species. The beetle is native to eastern Asia and has become an invasive pest in North America and Europe,...

Difference in tree growth responses to climate at the upper treeline: Qilian Juniper in the Anyemaqen Mountains.

Science.gov (United States)

Peng, Jianfeng; Gou, Xiaohua; Chen, Fahu; Li, Jinbao; Liu, Puxing; Zhang, Yong; Fang, Keyan

2008-08-01

Three ring-width chronologies were developed from Qilian Juniper (Sabina przewalskii Kom.) at the upper treeline along a west-east gradient in the Anyemaqen Mountains. Most chronological statistics, except for mean sensitivity (MS), decreased from west to east. The first principal component (PC1) loadings indicated that stands in a similar climate condition were most important to the variability of radial growth. PC2 loadings decreased from west to east, suggesting the difference of tree-growth between eastern and western Anyemaqen Mountains. Correlations between standard chronologies and climatic factors revealed different climatic influences on radial growth along a west-east gradient in the study area. Temperature of warm season (July-August) was important to the radial growth at the upper treeline in the whole study area. Precipitation of current May was an important limiting factor of tree growth only in the western (drier) upper treeline, whereas precipitation of current September limited tree growth in the eastern (wetter) upper treeline. Response function analysis results showed that there were regional differences between tree growth and climatic factors in various sampling sites of the whole study area. Temperature and precipitation were the important factors influencing tree growth in western (drier) upper treeline. However, tree growth was greatly limited by temperature at the upper treeline in the middle area, and was more limited by precipitation than temperature in the eastern (wetter) upper treeline.

Gluing of Eastern Hardwoods: A Review

Science.gov (United States)

Terry Sellers; James R. McSween; William T. Nearn

1988-01-01

Over a period of years, inrreasing demand for softwoods in the Eastern United States has led to an increase in the growth of hardwoods on cut-over softwood sites. Unfortunately these hardwood trees are often of a size and shape unsuitable for the production of high-grade lumber and veneer. They do, however, represent a viable, economic soures of raw material for...

What's known about managing eastern white pine

Science.gov (United States)

Charles R. Lockard

1959-01-01

At the 1957 meeting of the Northeastern Forest Research Advisory Council the comment was made that although Eastern white pine has been the most studied forest tree species in the Northeast, the only literature on the management of the species was in reports on isolated and uncoordinated studies. There was no comprehensive compendium of knowledge.

Wind Energy Conversion by Plant-Inspired Designs.

Science.gov (United States)

McCloskey, Michael A; Mosher, Curtis L; Henderson, Eric R

2017-01-01

In 2008 the U.S. Department of Energy set a target of 20% wind energy by 2030. To date, induction-based turbines form the mainstay of this effort, but turbines are noisy, perceived as unattractive, a potential hazard to bats and birds, and their height hampers deployment in residential settings. Several groups have proposed that artificial plants containing piezoelectric elements may harvest wind energy sufficient to contribute to a carbon-neutral energy economy. Here we measured energy conversion by cottonwood-inspired piezoelectric leaves, and by a "vertical flapping stalk"-the most efficient piezo-leaf previously reported. We emulated cottonwood for its unusually ordered, periodic flutter, properties conducive to piezo excitation. Integrated over 0°-90° (azimuthal) of incident airflow, cottonwood mimics outperformed the vertical flapping stalk, but they produced < daW per conceptualized tree. In contrast, a modest-sized cottonwood tree may dissipate ~ 80 W via leaf motion alone. A major limitation of piezo-transduction is charge generation, which scales with capacitance (area). We thus tested a rudimentary, cattail-inspired leaf with stacked elements wired in parallel. Power increased systematically with capacitance as expected, but extrapolation to acre-sized assemblages predicts < daW. Although our results suggest that present piezoelectric materials will not harvest mid-range power from botanic mimics of convenient size, recent developments in electrostriction and triboelectric systems may offer more fertile ground to further explore this concept.

Tree mortality estimates and species distribution probabilities in southeastern United States forests

Science.gov (United States)

Martin A. Spetich; Zhaofei Fan; Zhen Sui; Michael Crosby; Hong S. He; Stephen R. Shifley; Theodor D. Leininger; W. Keith Moser

2017-01-01

Stresses to trees under a changing climate can lead to changes in forest tree survival, mortality and distribution.  For instance, a study examining the effects of human-induced climate change on forest biodiversity by Hansen and others (2001) predicted a 32% reduction in loblolly–shortleaf pine habitat across the eastern United States.  However, they also...

Estimation of Tree Cover in an Agricultural Parkland of Senegal Using Rule-Based Regression Tree Modeling

Directory of Open Access Journals (Sweden)

Stefanie M. Herrmann

2013-10-01

Full Text Available Field trees are an integral part of the farmed parkland landscape in West Africa and provide multiple benefits to the local environment and livelihoods. While field trees have received increasing interest in the context of strengthening resilience to climate variability and change, the actual extent of farmed parkland and spatial patterns of tree cover are largely unknown. We used the rule-based predictive modeling tool Cubist® to estimate field tree cover in the west-central agricultural region of Senegal. A collection of rules and associated multiple linear regression models was constructed from (1 a reference dataset of percent tree cover derived from very high spatial resolution data (2 m Orbview as the dependent variable, and (2 ten years of 10-day 250 m Moderate Resolution Imaging Spectrometer (MODIS Normalized Difference Vegetation Index (NDVI composites and derived phenological metrics as independent variables. Correlation coefficients between modeled and reference percent tree cover of 0.88 and 0.77 were achieved for training and validation data respectively, with absolute mean errors of 1.07 and 1.03 percent tree cover. The resulting map shows a west-east gradient from high tree cover in the peri-urban areas of horticulture and arboriculture to low tree cover in the more sparsely populated eastern part of the study area. A comparison of current (2000s tree cover along this gradient with historic cover as seen on Corona images reveals dynamics of change but also areas of remarkable stability of field tree cover since 1968. The proposed modeling approach can help to identify locations of high and low tree cover in dryland environments and guide ground studies and management interventions aimed at promoting the integration of field trees in agricultural systems.

Environmental Assessment for the Aeromedical Evacuation Formal Training Unit, Wright-Patterson Air Force Base

Science.gov (United States)

2012-05-01

pennsylvanica), White Ash (Fraxinus americana), Shingle Oak (Quercus imbricaria), Northern Red Oak (Quercus rubra), Slippery Elm (Ulmus rubra...American Elm (Ulmus americana), Eastern Cottonwood (Populus deltoides), Silver Maple (Acer saccharinum), Sassafras (Sassafras albidum), Post Oak (Quercus

Lichens of fruit trees in the selected locations in Podlaskie Voivodeship [North-Eastern Poland

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Matwiejuk Anna

2017-12-01

Full Text Available The aim of this paper is to present the diversity of the lichen species on fruit trees (Malus sp., Pyrus sp., Prunus sp. and Cerasus sp. growing in orchards in selected villages and towns in the Podlaskie Voivodeship. Fifty-six species of lichens were found. These were dominated by common lichens found on the bark of trees growing in built-up areas with prevailing heliophilous and nitrophilous species of the genera Physcia and Phaeophyscia. A richer lichen biota is characteristic of apple trees (52 species and pear trees (36. Lichens of the apple trees constitute 78% of the biota of this phorophyte growing in the fruit orchards in Poland. Of the recorded species, only two (Ramalina farinacea, Usnea hirta are covered by partial protection in Poland.

Timber tree regeneration along abandoned logging roads in a tropical Bolivian forest

DEFF Research Database (Denmark)

Nabe-Nielsen, J.; Severiche, W.; Fredericksen, T.

2007-01-01

Sustainable management of selectively logged tropical forests requires that felled trees are replaced through increased recruitment and growth. This study compares road track and roadside regeneration with regeneration in unlogged and selectively logged humid tropical forest in north-eastern Boli......Sustainable management of selectively logged tropical forests requires that felled trees are replaced through increased recruitment and growth. This study compares road track and roadside regeneration with regeneration in unlogged and selectively logged humid tropical forest in north......-eastern Bolivia. Some species benefited from increased light intensities on abandoned logging roads. Others benefited from low densities of competing vegetation on roads with compacted soils. This was the case for the small-seeded species Ficus boliviana C.C. Berg and Terminalia oblonga (Ruiz & Pav.) Steud. Some...

Okadaic acid and trifluoperazine enhance Agrobacterium-mediated transformation in eastern white pine.

Science.gov (United States)

Tang, Wei; Lin, Jinxing; Newton, Ronald J

2007-05-01

Mature zygotic embryos of recalcitrant Christmas tree species eastern white pine (Pinus strobus L.) were used as explants for Agrobacterium tumefaciens strain GV3101-mediated transformation using the uidA (beta-Glucuronidase) gene as a reporter. Influence of the time of sonication and the concentrations of protein phosphatase inhibitor (okadaic acid) and kinase inhibitor (trifluoperazine) on Agrobacterium-mediated transformation have been evaluated. A high transformation frequency was obtained after embryos were sonicated for 45-50 s, or treated with 1.5-2.0 microM okadaic acid or treated with 100-200 microM trifluoperazine, respectively. Protein phosphatase and kinase inhibitors enhance Agrobacterium-mediated transformation in eastern white pine. A 2-3.5-fold higher rate of hygromycin-resistant callus was obtained with an addition of 2 microM okadaic acid or 150 microM trifluoperazine or sonicated embryos for 45 s. Stable integration of the uidA gene in the plant genome of eastern white pine was confirmed by polymerase chain reaction (PCR), Southern and northern blot analyses. These results demonstrated that a stable and enhanced transformation system has been established in eastern white pine and this system would provide an opportunity to transfer economically important genes into this Christmas tree species.

There is no temperature dependence of net biochemical fractionation of hydrogen and oxygen isotopes in tree-ring cellulose.

Science.gov (United States)

Roden, J S; Ehleringer, J R

2000-01-01

The isotopic composition of tree-ring cellulose was obtained over a two-year period from small diameter, riparian zone trees along an elevational transect in Big Cottonwood Canyon, Utah, USA to test for a possible temperature dependence of net biological fractionation during cellulose synthesis. The isotope ratios of stream water varied by only 3.6% and 0.2% in deltaD and delta18O, respectively, over an elevation change of 810m. The similarity in stream water and macroenvironment over the short (13km) transect produced nearly constant stem and leaf water deltaD and delta18O values. In addition, what few seasonal variations observed in the isotopic composition of source water and atmospheric water vapor or in leaf water evaporative enrichment were experienced equally by all sites along the elevational transect. The temperature at each site along the transect spanned a range of > or = 5 degrees C as calculated using the adiabatic lapse rate. Since the deltaD and delta18O values of stem and leaf water varied little for these trees over this elevation/temperature transect, any differences in tree-ring cellulose deltaD and delta18O values should have been associated with temperature effects on net biological fractionation. However, the slopes of the regressions of elevation versus the deltaD and delta18O values of tree-ring cellulose were not significantly different from zero indicating little or no temperature dependence of net biological fractionation. Therefore, cross-site climatic reconstruction studies using the isotope ratios of cellulose need not be concerned that temperatures during the growing season have influenced results.

Insertional mutagenesis in Populus: relevance and feasibility

Science.gov (United States)

Victor Busov; Matthias Fladung; Andrew Groover; Steven Strauss

2005-01-01

The recent sequencing of the first tree genome, that of the black cottonwood (Populus trichocarpa), opens a new chapter in tree functional genomics. While the completion of the genome is a milestone, mobilizing this significant resource for better understanding the growth and development of woody perennials will be an even greater undertaking in the...

Investigating Strain Transfer Along the Southern San Andreas Fault: A Geomorphic and Geodetic Study of Block Rotation in the Eastern Transverse Ranges, Joshua Tree National Park, CA

Science.gov (United States)

Guns, K. A.; Bennett, R. A.; Blisniuk, K.

2017-12-01

To better evaluate the distribution and transfer of strain and slip along the Southern San Andreas Fault (SSAF) zone in the northern Coachella valley in southern California, we integrate geological and geodetic observations to test whether strain is being transferred away from the SSAF system towards the Eastern California Shear Zone through microblock rotation of the Eastern Transverse Ranges (ETR). The faults of the ETR consist of five east-west trending left lateral strike slip faults that have measured cumulative offsets of up to 20 km and as low as 1 km. Present kinematic and block models present a variety of slip rate estimates, from as low as zero to as high as 7 mm/yr, suggesting a gap in our understanding of what role these faults play in the larger system. To determine whether present-day block rotation along these faults is contributing to strain transfer in the region, we are applying 10Be surface exposure dating methods to observed offset channel and alluvial fan deposits in order to estimate fault slip rates along two faults in the ETR. We present observations of offset geomorphic landforms using field mapping and LiDAR data at three sites along the Blue Cut Fault and one site along the Smoke Tree Wash Fault in Joshua Tree National Park which indicate recent Quaternary fault activity. Initial results of site mapping and clast count analyses reveal at least three stages of offset, including potential Holocene offsets, for one site along the Blue Cut Fault, while preliminary 10Be geochronology is in progress. This geologic slip rate data, combined with our new geodetic surface velocity field derived from updated campaign-based GPS measurements within Joshua Tree National Park will allow us to construct a suite of elastic fault block models to elucidate rates of strain transfer away from the SSAF and how that strain transfer may be affecting the length of the interseismic period along the SSAF.

CLIMATE CHANGE AND ORIENTAL SPRUCE (PICEA ORIENTALIS ECOSYSTEMS IN EASTERN BLACKSEA REGION OF TURKEY

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Aydın Tüfekçioğlu

2008-04-01

Full Text Available Climate change has been getting more attention from scientific community recently. Eastern Black Sea Region of Turkey will get significant influences from the climate change according to regional climate model (RegCM3. Oriental spruce (Picea orientalis L. is an important tree species of Turkey and it only grows in the Eastern Black Sea Region of Turkey. With the increase in global warming, spruce forests started to have serious bark beetle problems. More than 200 000 trees died in the region recently due to bark beetle attack. We used existing literature related to oriental spruce and future climate of the region and field observations done in the different times to assess current status of the spruce stands. Future climate of the region has been predicted using RegCM3 regional climate model. Climate change could significantly influence distribution, diversity, structure and stability of the oriental spruce ecosystems. According to RegCM3 regional climate model, the temperatures will increase 2-4 °C in the region in the next century. Future climate scenarios predict 200-300 mm increases in precipitation in the eastern part of the region while the western part won't have any increase in precipitation in the next century. Temperature increases in the western part of the region can cause more stress on spruce trees and would probably increase bark beetle attacks. Also, fire could become an important threat in the western part of the region. It is possible to observe 400-800 m upward shift in the spruce belt in the western part. Treeline of spruce stands would probably move upward both in western and eastern part of the North-eastern Blacksea Region.

Silvicultural guide for northern white-cedar (eastern white cedar)

Science.gov (United States)

Emmanuelle Boulfroy; Eric Forget; Philip V. Hofmeyer; Laura S. Kenefic; Catherine Larouche; Guy Lessard; Jean-Martin Lussier; Fred Pinto; Jean-Claude Ruel; Aaron. Weiskittel

2012-01-01

Northern white-cedar (eastern white cedar; Thuja occidentalis L.) is an important tree species in the northeastern United States and adjacent Canada, occurring both in pure stands and as a minor species in mixed stands of hardwoods or other softwoods. Yet practitioners have little and often contradictory information about cedar ecology and...

( Mangifera indica L.) in Harari Regional State, Eastern Ethiopia

African Journals Online (AJOL)

Mango production covers 35% of the total acreage allotted for fruit production in Harari Regional State, eastern Ethiopia. However, there is a declining trend in yield and quality of fruits from the trees. Therefore, this study was conducted to assess the status, practices and challenges of mango production in the study area.

Antibiotics Do Not Control Blister Rust in Eastern White Pine Seedlings

Science.gov (United States)

William R. Phelps; Ray Weber

1968-01-01

To prevent blister rust infections in Eastern white pine seedlings, the antibiotics, cycloheximide (acti-dione) and Phytoactin, were tested in root dips, root slurries, and foliar drenches before planting and after planting the trees. None of the methods and materials tested was effective.

Influence of Hemlock Woolly Adelgid Infestation Levels on Water Stress in Eastern Hemlocks within the Great Smoky Mountains National Park, U.S.A.

Directory of Open Access Journals (Sweden)

Carla Coots

2015-01-01

Full Text Available Extensive mortality of eastern hemlock, Tsuga canadensis (L. Carrière, resulting from infestation by hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae, has occurred throughout the eastern United States. Although imidacloprid treatment can reduce tree mortality, its effectiveness can be influenced by several factors including tree water stress. The relationship between water stress and infestation rates is unknown, and an understanding of these could greatly increase the efficiency of management for this invasive insect. The primary objective of this study was to assess water stress at three levels of hemlock woolly adelgid infestations. Water stress was measured monthly for 13 months in eastern hemlocks classified as <25%, 25%–75%, and >75% infested. The highest level of water stress was found in those trees with hemlock woolly adelgid infestation levels greater than 75%. The lowest level of water stress was found in those trees with less than 25% hemlock woolly adelgid infestation levels. Knowledge of these effects can contribute to development of more effective chemical management strategies.

Stem anatomy variation in cottonwood

Science.gov (United States)

A.N. Foulger; J. Hacskaylo

1968-01-01

Investigations of mineral nutrient-tree growth relationships have dealt mainly with associations involving foliage composition, root formation, or volume production of wood. Few studies have been concerned with changes in wood anatomy associated with element deficiency. In 1949 Davis reported that calcium deficiency was accompanied by a reduction of primary tissue and...

Climate Response of Tree Radial Growth at Different Timescales in the Qinling Mountains.

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Changfeng Sun

Full Text Available The analysis of the tree radial growth response to climate is crucial for dendroclimatological research. However, the response relationships between tree-ring indices and climatic factors at different timescales are not yet clear. In this study, the tree-ring width of Huashan pine (Pinus armandii from Huashan in the Qinling Mountains, north-central China, was used to explore the response differences of tree growth to climatic factors at daily, pentad (5 days, dekad (10 days and monthly timescales. Correlation function and linear regression analysis were applied in this paper. The tree-ring width showed a more sensitive response to daily and pentad climatic factors. With the timescale decreasing, the absolute value of the maximum correlation coefficient between the tree-ring data and precipitation increases as well as temperature (mean, minimum and maximum temperature. Compared to the other three timescales, pentad was more suitable for analysing the response of tree growth to climate. Relative to the monthly climate data, the association between the tree-ring data and the pentad climate data was more remarkable and accurate, and the reconstruction function based on the pentad climate was also more reliable and stable. We found that the major climatic factor limiting Huashan pine growth was the precipitation of pentads 20-35 (from April 6 to June 24 rather than the well-known April-June precipitation. The pentad was also proved to be a better timescale for analysing the climate and tree growth in the western and eastern Qinling Mountains. The formation of the earlywood density of Chinese pine (Pinus tabulaeformis from Shimenshan in western Qinling was mainly affected by the maximum temperature of pentads 28-32 (from May 16 to June 9. The maximum temperature of pentads 28-33 (from May 16 to June 14 was the major factor affecting the ring width of Chinese pine from Shirenshan in eastern Qinling.

Reconstructions of spring/summer precipitation for the Eastern Mediterranean from tree-ring widths and its connection to large-scale atmospheric circulation

Energy Technology Data Exchange (ETDEWEB)

Touchan, Ramzi; Funkhouser, Gary; Hughes, Malcolm K. [The University of Arizona, Laboratory of Tree-Ring Research, Tucson, AZ (United States); Xoplaki, Elena; Luterbacher, Juerg [University of Bern, Institute of Geography and NCCR Climate, Bern (Switzerland); Erkan, Nesat [Southwest Anatolia Forest Research Institute (SAFRI), Antalya (Turkey); Akkemik, Uenal [University of Istanbul, Faculty of Forestry, Department of Forest Botany, Bahcekoey-Istanbul (Turkey); Stephan, Jean [Ministry of Agriculture, Forestry Department, Beirut (Lebanon)

2005-07-01

This study represents the first large-scale systematic dendroclimatic sampling focused on developing chronologies from different species in the eastern Mediterranean region. Six reconstructions were developed from chronologies ranging in length from 115 years to 600 years. The first reconstruction (1885-2000) was derived from principal components (PCs) of 36 combined chronologies. The remaining five, 1800-2000, 1700-2000, 1600-2000, 1500-2000 and 1400-2000 were developed from PCs of 32, 18, 14, 9, and 7 chronologies, respectively. Calibration and verification statistics for the period 1931-2000 show good levels of skill for all reconstructions. The longest period of consecutive dry years, defined as those with less than 90% of the mean of the observed May-August precipitation, was 5 years (1591-1595) and occurred only once during the last 600 years. The longest reconstructed wet period was 5 years (1601-1605 and 1751-1755). No long term trends were found in May-August precipitation during the last few centuries. Regression maps are used to identify the influence of large-scale atmospheric circulation on regional precipitation. In general, tree-ring indices are influenced by May-August precipitation, which is driven by anomalous below (above) normal pressure at all atmospheric levels and by convection (subsidence) and small pressure gradients at sea level. These atmospheric conditions also control the anomaly surface air temperature distribution which indicates below (above) normal values in the southern regions and warmer (cooler) conditions north of around 40 N. A compositing technique is used to extract information on large-scale climate signals from extreme wet and dry summers for the second half of the twentieth century and an independent reconstruction over the last 237 years. Similar main modes of atmospheric patterns and surface air temperature distribution related to extreme dry and wet summers were identified both for the most recent 50 years and the last

The role of coffee based agroforestry system in tree diversity conservation in Eastern Uganda

DEFF Research Database (Denmark)

Negawo, Worku Janka; Beyene, Dejene Nigatu

2017-01-01

Agroforestry farming system comprises considerable cultivated land area in the tropics. Despite the economic and social benefits of the system for farmers, it is also known to have an important role in the conservation of tree species. This study aims to evaluate the composition and distribution...... of indigenous tree species in coffee farms was lower than that of forest reserve. Similarly, tree species richness per plot, Shannon and Simpson diversity indexes of forest reserve were significantly (p

Recent expansion of erect shrubs in the Low Arctic: evidence from Eastern Nunavik

International Nuclear Information System (INIS)

Tremblay, Benoît; Lévesque, Esther; Boudreau, Stéphane

2012-01-01

In order to characterize shrub response near the treeline in Eastern Nunavik (Québec), a region under extensive warming since the 1990s, we compared two series (1964 and 2003) of vertical aerial photos from the vicinity of Kangiqsualujjuaq. Our study revealed a widespread increase in erect woody vegetation cover. During the 40 years spanning the two photo series, erect shrub and tree cover increased markedly on more than half of the land surface available for new colonization or infilling. Within the 7.2 km 2 analysed, areas with dense shrub and tree cover (>90%) increased from 34% to 44% whereas areas with low cover (<10%) shrank from 45% to 29%. This increase in cover of trees and shrubs occurred throughout the landscape regardless of altitude, slope angle and exposure, although to varying extents. The main shrub species involved in this increase was Betula glandulosa Michx. (dwarf birch), which was present in 98% and dominant in 85% of the 345 plots. In addition, numerous seedlings and saplings of Larix laricina (Du Roi) K Koch (eastern larch) were found above the treeline (25% of the plots), suggesting that the altitudinal treeline might shift upslope in the near future. Sites that remained devoid of erect woody vegetation in 2003 were either characterized by the absence of a suitable seedbed or by harsh local microclimatic conditions (wind exposure or excessive drainage). Our results indicate dramatic increases in shrub and tree cover at a Low Arctic site in Eastern Nunavik, contributing to a growing number of observations of woody vegetation change from various areas around the North. (letter)

Polyphyly of the Padus group of Prunus (Rosaceae) and the evolution of biogeographic disjunctions between eastern Asia and eastern North America.

Science.gov (United States)

Liu, Xiao-Lin; Wen, Jun; Nie, Ze-Long; Johnson, Gabriel; Liang, Zong-Suo; Chang, Zhao-Yang

2013-05-01

Prunus subgenus Padus is a group with a wide distribution in temperate eastern Asia and eastern North America with one species extending to Europe and one to Central America. Phylogenetic relationships of subgenus Padus were reconstructed using sequences of nuclear ribosomal ITS, and plastid ndhF gene, and rps16 intron and rpl16 intron. Prunus subgenus Padus is shown to be polyphyletic. Taxa of subgenus Padus and subgenus Laurocerasus are highly intermixed in both the ITS and the plastid trees. The results support two disjunctions between eastern North America and Eurasia within the Padus group. One disjunction is between Prunus virginiana of eastern North America and P. padus of Eurasia, estimated to have diverged at 2.99 (95 % HPD 0.59-6.15)-4.1 (95 % HPD 0.63-8.59) mya. The other disjunction is between P. serotina and its Asian relatives. The second disjunction may have occurred earlier than the former one, but the age estimate is difficult due to the unresolved phylogenetic position of the P. serotina complex.

Characteristics of Blister Rust Cankers on Eastern White Pine

Science.gov (United States)

William R. Phelps; Ray Weber

1969-01-01

The growth, development, and sporulation of white pine blister rust cankers were studied on eastern white pine in Wisconsin and Minnesota. Three district canker types were identified on the basis of physical appearance, growth rate, and sporulation. Canker growth rate and sporulation decreased as tree size or age increased, and many cankers apparently became inactive...

Quantifying Environmental Limiting Factors on Tree Cover Using Geospatial Data

NARCIS (Netherlands)

Greenberg, Jonathan; Ferreira Dos Santos, Maria Joao; Dobrowski, Solomon; Vanderbilt, Vern; Ustin, Susan

2015-01-01

Environmental limiting factors (ELFs) are the thresholds that determine the maximum or minimum biological response for a given suite of environmental conditions. We asked the following questions: 1) Can we detect ELFs on percent tree cover across the eastern slopes of the Lake Tahoe Basin, NV? 2)

Holocene tree-line variability in the Kauner Valley, Central Eastern Alps, indicated by dendrochronological analysis of living trees and subfossil logs

NARCIS (Netherlands)

Nicolussi, Kurt; Kaufmann, Matthias; Patzelt, Gernot; van der Plicht, Johannes; Thurner, Andrea

2005-01-01

The altitude of the Alpine tree-line has often been used as proxy for the climatic conditions in the Holocene epoch. The usual approach for establishing a record for this proxy is the analysis of pollen and macro remains. We analysed living trees and subfossil logs from the timberline ecotone in the

Trees as indicators of subterranean migration of tritium at a commercial shallow land radioactive waste disposal site

International Nuclear Information System (INIS)

Rickard, W.H.; Kirby, L.J.

1984-09-01

Leaf water and tree sap collected from deciduous trees in a natural forest growing outside the fenced exclusion area of the Maxey Flats Waste Disposal Facility in eastern Kentucky, USA were radiochemically analyzed to detect movement of tritium via subterranean flows of water at depths of three meters. These data indicate that trees can be used to detect the subterranean migration of tritium from shallow land burial sites. 4 references, 5 figures, 1 table

Evaluating forest land development effects on private forestry in eastern Oregon.

Science.gov (United States)

Jeffrey D. Kline; David L. Azuma

2007-01-01

Research suggests that forest land development can reduce the productivity of remaining forest land because private forest owners reduce their investments in forest management. We developed empirical models describing forest stocking, thinning, harvest, and postharvest tree planting in eastern Oregon, as functions of stand and site characteristics, ownership, and...

Forest production dynamics along a wood density spectrum in eastern US forests

Science.gov (United States)

C.W. Woodall; M.B. Russell; B.F. Walters; A.W. D' Amato; K. Zhu; S.S. Saatchi

2015-01-01

Emerging plant economics spectrum theories were confirmed across temperate forest systems of the eastern US where the use of a forest stand's mean wood density elucidated forest volume and biomass production dynamics integrating aspects of climate, tree mortality/growth, and rates of site occupancy.

Drought-induced legacy effects in wood growth across the Eastern and Midwestern U.S. are mediated by site climate, tree age, and drought sensitivity

Science.gov (United States)

Kannenberg, S.; Maxwell, J. T.; Pederson, N.; D'Orangeville, L.; Phillips, R.

2017-12-01

While it is widely known that drought reduces carbon (C) uptake in temperate forests, tree growth can also remain stagnant post-drought despite favorable climatic conditions. While such "legacy effects" are well established, the degree to which these effects depend on species identity or variability in site conditions is poorly quantified. We sought to uncover how site, species, climate, and tree age interact to affect the presence and magnitude of legacy effects in temperate trees following drought. To do this, we assembled dendrochronological records of 18 common species across 94 sites in Eastern and Midwestern U.S. forests and quantified drought-induced changes in wood growth in the year of the drought (hereafter "drought sensitivity") and the years after the drought (i.e., legacy effects). We predicted that species particularly prone to hydraulic damage (e.g., oaks) would have the least drought sensitivity yet experience larger legacy effects, and that this effect would be exacerbated at arid sites. Across all species and sites, wood growth was reduced by 14% in the year of the drought and by 7% post-drought. Surprisingly, legacy effects were smaller for oak species and larger across species known to be more drought sensitive (e.g. tulip poplar, maple, birch). As a result, we observed a positive relationship between a species' drought sensitivity and that species' legacy effect. These legacy effects were similar in size across a range of drought severities. Surprisingly, legacy effects were smaller in more arid sites - contrary to previous investigations in dryland ecosystems - perhaps indicating the role of adaptation in mediating a tree's recovery from drought. In addition, many species actually decreased the size of their legacy effects as they aged, despite no change in drought responses. Our results run contrary to our predictions, as species with the greatest drought sensitivity had the least ability to recover, and that younger mesic forests- not arid

Variation in plant defense against invasive herbivores: evidence for a hypersensitive response in eastern hemlocks (Tsuga canadensis).

Science.gov (United States)

Radville, Laura; Chaves, Arielle; Preisser, Evan L

2011-06-01

Herbivores can trigger a wide array of morphological and chemical changes in their host plants. Feeding by some insects induces a defensive hypersensitive response, a defense mechanism consisting of elevated H(2)O(2) levels and tissue death at the site of herbivore feeding. The invasive hemlock woolly adelgid Adelges tsugae ('HWA') and elongate hemlock scale Fiorinia externa ('EHS') feed on eastern hemlocks; although both are sessile sap feeders, HWA causes more damage than EHS. The rapid rate of tree death following HWA infestation has led to the suggestion that feeding induces a hypersensitive response in hemlock trees. We assessed the potential for an herbivore-induced hypersensitive response in eastern hemlocks by measuring H(2)O(2) levels in foliage from HWA-infested, EHS-infested, and uninfested trees. Needles with settled HWA or EHS had higher H(2)O(2) levels than control needles, suggesting a localized hypersensitive plant response. Needles with no direct contact to settled HWA also had high H(2)O(2) levels, suggesting that HWA infestation may induce a systemic defense response in eastern hemlocks. There was no similar systemic defensive response in the EHS treatment. Our results showed that two herbivores in the same feeding guild had dramatically different outcomes on the health of their shared host.

Bacterial Leaf Scorch of Amenity Trees a Wide-Spread Problem of Economic Significance to the Urban Forest

Science.gov (United States)

James Lashomb; Alan Iskra; Ann Brooks Gould; George Hamilton

2003-01-01

Bacterial leaf scorch (BLS) of amenity trees is caused by the bacterium Xylella fastidiosa, a xylem-limited pathogen that causes water stress resulting in leaf scorch, decline, and eventual death of affected trees. Recent surveys indicate that BLS is widespread throughout the eastern half of the United States. In New Jersey, BLS primarily affects red and pin oaks...

Development of Ash Dieback in South-Eastern Germany and the Increasing Occurrence of Secondary Pathogens

Directory of Open Access Journals (Sweden)

Heike D. Lenz

2016-02-01

Full Text Available Since its first identification in Poland in 2006, the ascomycete Hymenoscyphus fraxineus has caused massive dieback of Fraxinus excelsior in the countries of eastern, northern and central Europe. This work shows the development, expansion, and severity of the disease in south-eastern Germany for a period of four years, starting in 2010. Differences between habitats, as well as age classes have been captured. The presence and the amount of potentially resistant trees were proven over the years, to determine how high the resistance level might be. Typical disease symptoms are the wilting of leaves, necrotic lesions in the bark and reddish discolorations of branches and stems. In addition, stem necroses also appear by infection with species of Armillaria. Therefore, special attention has been given to Armillaria species in affected ash stands but also to other secondary pathogens, like ash bark beetles. It is shown that breeding galleries of Hylesinus fraxini are only found in trees that have recently died and thus Hylesinus fraxini is still acting as a secondary opportunistic pathogen. In contrast, Armillaria spp. can be considered as serious pathogens of weakened ash trees. In different ash stands, typical symptoms of infection can be found. A relationship between stem base necrotic lesions and vitality was examined. It is shown that necrotic lesions severely contribute to accelerating the mortality of ash trees. In addition to the high infection pressure by H. fraxineus, the high inoculum of Armillaria in the soil facilitates further infections and, thus, likewise endangers the survival of potentially resistant trees. In the following years, forest conversion and seed harvest in affected ash stands will have to be urgently considered to avoid tree gaps on a large scale. Furthermore, infection assays of potentially resistant trees with ensuing breeding programmes should be initially started for the conservation of this ecologically and

Competition for dead trees between humans and aye-ayes (Daubentonia madagascariensis) in central eastern Madagascar.

Science.gov (United States)

Miller, Rose T; Raharison, Jean-Luc; Irwin, Mitchell T

2017-04-01

The destruction and degradation of forest habitats are major threats to the sustainability of lemur populations in Madagascar. Madagascan landscapes often contain forest fragments that represent refuges for native fauna, while also being used for firewood and timber by local human populations. As undisturbed forest becomes increasingly scarce, understanding resource competition between humans and wildlife in disturbed habitats will be increasingly important. We tested the hypothesis that Malagasy and aye-ayes (Daubentonia madagascariensis) compete for the limited number of dead trees in rainforest fragments at Tsinjoarivo, Madagascar. We surveyed 2.16 ha within five fragments (range 5-228 ha) surrounding human settlements to quantify the density of dead trees and traces of both human and aye-aye activity. Neither aye-aye nor human traces were distributed according to the availability of particular trees species, and aye-ayes and Malagasy apparently preferred several different species. Although overlap was recorded in tree species used, human use tended to be positively correlated with a species' desirability as firewood, while a negative relationship was seen for aye-ayes. Both consumers used trees of similar diameter at breast height, but those used by aye-ayes tended to be older, suggesting that human use might precede usefulness for aye-ayes. Finally, the density of dead trees and aye-aye traces were highest in smaller fragments, but human traces did not vary across fragment size. Although further study is needed to better quantify the aye-aye diet in this region, these data suggest that aye-ayes and local people compete for dead trees, and this competition could constitute a pressure on aye-aye populations.

Acidity of tree bark as a bioindicator of forest pollution in southern Poland

Energy Technology Data Exchange (ETDEWEB)

Grodznska, K

1976-01-01

PH values and buffering capacity were determined for bark samples of 5 deciduous trees (oak, alder, hornbeam, ash, linden), one shrub (hazel) and one coniferous tree (scots pine) in the Cracow industrial region (southern Poland) and for comparison in the Bialowieza Forest (north-eastern Poland). The correlation was found between acidification of tree bark and air pollution by SO/sub 2/ in these areas. All trees showed the least acidic reaction in the control area (Bialowieza Forest), more acidic in Niepolomice Forest and the most acidic in the center of Cracow city. The buffering capacity of the bark against alkali increased with increasing air pollution. The seasonal fluctuations of pH values is recommended as a sensitive and simple indicator of air pollution.

Distance-independent individual tree diameter-increment model for Thuya [Tetraclinis articulata (VAHL.) MAST.] stands in Tunisia

OpenAIRE

T. Sghaier; M. Tome; J. Tome; M. Sanchez-Gonzalez; I. Cañellas; R. Calama

2013-01-01

Aim of study: The aim of the work was to develop an individual tree diameter-increment model for Thuya (Tetraclinis articulata) in Tunisia.Area of study: The natural Tetraclinis articulata stands at Jbel Lattrech in north-eastern of Tunisia.Material and methods:  Data came from 200 trees located in 50 sample plots. The diameter at age t and the diameter increment for the last five years obtained from cores taken at breast height were measured for each tree. Four difference equations derived f...

Coevolution of floodplain and riparian forest dynamics on large, meandering rivers

Science.gov (United States)

Stella, J. C.; Riddle, J. D.; Battles, J. J.

2012-12-01

On large meandering rivers, riparian forests coevolve with the floodplains that support them. Floodplain characteristics such as local disturbance regime, deposition rates and sediment texture drive plant community dynamics, which in turn feed back to the abiotic processes. We investigated floodplain and riparian forest coevolution along the along the Sacramento River (California, USA), a large, mediterranean-climate river that has been extensively regulated for 70 years, but whose 160-km middle reach (Red Bluff to Colusa) retains some channel mobility and natural forest stands. Guided by maps of floodplain change over time and current vegetation cover, we conducted an extensive forest inventory and chronosequence analysis to quantify how abiotic conditions and forest structural characteristics such as tree density, basal area and biomass vary with floodplain age. We inventoried 285 fixed-area plots distributed across 19 large point bars within vegetation patches ranging in age from 4 to 107 years. Two successional trajectories were evident: (1) shifting species dominance over time within forested areas, from willow to cottonwood to walnut, boxelder and valley oak; and (2) patches of shrub willow (primarily Salix exigua) that maintained dominance throughout time. Sediment accretion was reduced in the persistent willow plots compared to the successional forest stands, suggesting an association between higher flood energy and arrested succession. Forested stands 40-60 years old were the most extensive across the chronosequence in terms of floodplain area, and supported the highest biomass, species diversity, and functional wildlife habitat. These stands were dominated by Fremont cottonwood (Populus fremontii) and reached their maxima in terms of tree size and biomass at age 50 years. The persistent willow stands reached their structural maxima earlier (32 years) and supported lower biomass. Basal area and abundance of large trees decreased in stands >90 years old

Evaluating the Invasion of Red Cedar (Juniperus viriginiana) Downstream of Gavins Point Dam, Missouri National Recreational River

Science.gov (United States)

Greene, S.; Knox, J. C.

2013-12-01

Gavins Point Dam, the final dam on the main-stem Missouri River, alters downstream river form and function. Throughout a 59-mile downstream reach, the dam reduces overbank flooding and lowers the water surface by 1-3 meters. Under the dam-created hydro-geomorphic conditions, native cottonwood trees are unable to regenerate. The limited regeneration of native riparian cottonwoods, the lowered water surface, and the reduced overbank flooding creates a terrace environment within the riparian habitat. Consequently, red cedars, a native upland tree, are invading this new terrace-like riparian environment. To this end, we apply Bayesian statistical models to investigate patterns of red cedar riparian invasion and assess ecosystem function patterns along this flow-regulated reach. We set up plots within cottonwood stands along a 59-km reach downstream of Gavins Point Dam. Within each plot, we collected soil samples, litter samples, stem densities of trees, and collected cores of the largest cottonwood and largest red cedar in each plot. To assess influences of red cedar on soil indicators of ecosystem function and general patterns of ecosystem function within the study area, we measured organic carbon, nitrogen, pH, electrical conductivity, and hydrophobicity. To determine drivers and patterns of invasion and ecosystem function we conducted Bayesian linear regressions and means comparison tests. Red cedars existed along the floodplain prior to regulation. However, according to our tree age data and stem density data red cedars existed at a lower population than today. We found that 2 out of 565 red cedars established before the dam was completed. Also, we found no significant difference in soil properties between soils with established red cedar and soils with established cottonwood. By studying soil texture data, and interpreting fluvial geomorphic surfaces in the field and via aerial photography, we found soil texture generally reflects the type of fluvial surface

Rapid warming forces contrasting growth trends of subalpine fir ( Abies fabri ) at higher- and lower-elevations in the eastern Tibetan Plateau

Energy Technology Data Exchange (ETDEWEB)

Wang, Wenzhi; Jia, Min; Wang, Genxu; Zhu, Wanze; McDowell, Nate G.

2017-10-01

Tree radial growth is expected to increase at higher elevations under climate warming, while lower elevation tree growth is expected to decline. However, numerous studies have found tree radial growth responds consistently to climate along elevational gradients. Here, we sampled five plots across the subalpine Abies fabri forest belt on Gongga Mountain in the eastern Tibetan Plateau to determine tree radial growth trends and responses to climate. Three commonly used detrending methods all consistently showed that tree radial growth at high elevation (> 3100 m) increased, while tree growth declined at the lower elevations (2700 m–2900 m) over the last three decades. Increasing late-growing season temperature positively (p < 0.05) correlated to tree radial growth at higher elevations, but the sign of this relationship reversed to become negative at lower elevations. Moving-window correlation analyses indicated the difference between high and low elevations response to temperature variation increased strongly with warming. Placing our result into the global context, 62% of 39 published studies found that trees along elevation gradients respond divergently to warming, and that these are located in warmer and wetter regions of the Earth. Notably, 28% of studies found non-significant responses to temperature at both high and low elevations. Our findings in the subalpine mountain forest in the eastern Tibetan Plateau were consistent with the majority of published datasets, and imply increasing temperature benefit for tree populations at higher elevation, while warming dampens growth at lower elevations.

Peak discharge, flood frequency, and peak stage of floods on Big Cottonwood Creek at U.S. Highway 50 near Coaldale, Colorado, and Fountain Creek below U.S. Highway 24 in Colorado Springs, Colorado, 2016

Science.gov (United States)

Kohn, Michael S.; Stevens, Michael R.; Mommandi, Amanullah; Khan, Aziz R.

2017-12-14

The U.S. Geological Survey (USGS), in cooperation with the Colorado Department of Transportation, determined the peak discharge, annual exceedance probability (flood frequency), and peak stage of two floods that took place on Big Cottonwood Creek at U.S. Highway 50 near Coaldale, Colorado (hereafter referred to as “Big Cottonwood Creek site”), on August 23, 2016, and on Fountain Creek below U.S. Highway 24 in Colorado Springs, Colorado (hereafter referred to as “Fountain Creek site”), on August 29, 2016. A one-dimensional hydraulic model was used to estimate the peak discharge. To define the flood frequency of each flood, peak-streamflow regional-regression equations or statistical analyses of USGS streamgage records were used to estimate annual exceedance probability of the peak discharge. A survey of the high-water mark profile was used to determine the peak stage, and the limitations and accuracy of each component also are presented in this report. Collection and computation of flood data, such as peak discharge, annual exceedance probability, and peak stage at structures critical to Colorado’s infrastructure are an important addition to the flood data collected annually by the USGS.The peak discharge of the August 23, 2016, flood at the Big Cottonwood Creek site was 917 cubic feet per second (ft3/s) with a measurement quality of poor (uncertainty plus or minus 25 percent or greater). The peak discharge of the August 29, 2016, flood at the Fountain Creek site was 5,970 ft3/s with a measurement quality of poor (uncertainty plus or minus 25 percent or greater).The August 23, 2016, flood at the Big Cottonwood Creek site had an annual exceedance probability of less than 0.01 (return period greater than the 100-year flood) and had an annual exceedance probability of greater than 0.005 (return period less than the 200-year flood). The August 23, 2016, flood event was caused by a precipitation event having an annual exceedance probability of 1.0 (return

Comparative characterization of extractives in Alaskan Yellow, Eastern Red, and Western Red Cedars

Science.gov (United States)

Roderquita K. Moore; Doreen Mann; Gabriel Epstein; Phoebe Wagner; Brett Hinkforth; Jun Hyunji

2017-01-01

Softwoods, more specifically Cedars, are a set of tree species known to have extractive components with many different biological activities. Research has shown that certain compounds in Cedars are able to resist various forms of attack (microbial, fungal, insect, etc.). Juniperus virginiana (Eastern Red Cedar, Cupressus/Chamacyparis...

Value loss from weevil-caused defects in eastern white pine lumber

Science.gov (United States)

Myron D. Ostrander; Carl H. Stoltenberg

1957-01-01

Owners of eastern white pine stands suffer financially in several ways from attacks by the white-pine weevil (Pissodes strobi). Crooks, forks, and other weevil-caused tree-bole deformities increase bucking, logging, and sawing costs, and they reduce recoverable volumes. The injuries also reduce the average value of the lumber recovered. It is only with this reduction...

Stable carbon isotopic composition of tree rings from a pine tree from Augustów Wilderness, Poland, as a temperature and local environment conditions indicator.

Science.gov (United States)

Pawelczyk, Slawomira; Pazdur, Anna; Halas, Stanislaw

2004-06-01

Tree rings can be used as archives of climatic and environmental data with annual resolution. Tree rings widths, maximum late wood density and other parameters as stable composition in tree rings can be used for the reconstruction of past climatic and environmental changes. Stable carbon isotope ratios in tree rings may provide valuable information on past climatic conditions. 13C/12C ratios of plant organic matter can reflect corresponding 13C/12C ratio of atmospheric CO2 during formation of the rings. Investigations of isotopic carbon composition in tree rings from in the ecologically clean the Augustów Wilderness region in the north-eastern part of Poland (22 degrees 58'E, 53 degrees 51'N) (nowadays a sanctuary) were undertaken. Series of delta13C in alpha-cellulose and in wholewood were acquired. Those measurements constituted a part of more complex investigations of carbon isotope composition in tree rings including the measurements of radiocarbon concentration and tree ring widths. This article presents preliminary results. It is argued that contrary to the tree ring widths and delta13C in wholewood that do not reveal significant correlation with temperature, the variation of delta13C in the latewood alpha-cellulose is correlated with combined July and August temperatures. Copyright 2004 Taylor and Francis Ltd.

Tree rings and rainfall in the equatorial Amazon

Science.gov (United States)

Granato-Souza, Daniela; Stahle, David W.; Barbosa, Ana Carolina; Feng, Song; Torbenson, Max C. A.; de Assis Pereira, Gabriel; Schöngart, Jochen; Barbosa, Joao Paulo; Griffin, Daniel

2018-05-01

The Amazon basin is a global center of hydroclimatic variability and biodiversity, but there are only eight instrumental rainfall stations with continuous records longer than 80 years in the entire basin, an area nearly the size of the coterminous US. The first long moisture-sensitive tree-ring chronology has been developed in the eastern equatorial Amazon of Brazil based on dendrochronological analysis of Cedrela cross sections cut during sustainable logging operations near the Rio Paru. The Rio Paru chronology dates from 1786 to 2016 and is significantly correlated with instrumental precipitation observations from 1939 to 2016. The strength and spatial scale of the precipitation signal vary during the instrumental period, but the Rio Paru chronology has been used to develop a preliminary reconstruction of February to November rainfall totals from 1786 to 2016. The reconstruction is related to SSTs in the Atlantic and especially the tropical Pacific, similar to the stronger pattern of association computed for the instrumental rainfall data from the eastern Amazon. The tree-ring data estimate extended drought and wet episodes in the mid- to late-nineteenth century, providing a valuable, long-term perspective on the moisture changes expected to emerge over the Amazon in the coming century due to deforestation and anthropogenic climate change.

Partitioning of Multivariate Phenotypes using Regression Trees Reveals Complex Patterns of Adaptation to Climate across the Range of Black Cottonwood (Populus trichocarpa

Directory of Open Access Journals (Sweden)

Regis Wendpouire Oubida

2015-03-01

Full Text Available Local adaptation to climate in temperate forest trees involves the integration of multiple physiological, morphological, and phenological traits. Latitudinal clines are frequently observed for these traits, but environmental constraints also track longitude and altitude. We combined extensive phenotyping of 12 candidate adaptive traits, multivariate regression trees, quantitative genetics, and a genome-wide panel of SNP markers to better understand the interplay among geography, climate, and adaptation to abiotic factors in Populus trichocarpa. Heritabilities were low to moderate (0.13 to 0.32 and population differentiation for many traits exceeded the 99th percentile of the genome-wide distribution of FST, suggesting local adaptation. When climate variables were taken as predictors and the 12 traits as response variables in a multivariate regression tree analysis, evapotranspiration (Eref explained the most variation, with subsequent splits related to mean temperature of the warmest month, frost-free period (FFP, and mean annual precipitation (MAP. These grouping matched relatively well the splits using geographic variables as predictors: the northernmost groups (short FFP and low Eref had the lowest growth, and lowest cold injury index; the southern British Columbia group (low Eref and intermediate temperatures had average growth and cold injury index; the group from the coast of California and Oregon (high Eref and FFP had the highest growth performance and the highest cold injury index; and the southernmost, high-altitude group (with high Eref and low FFP performed poorly, had high cold injury index, and lower water use efficiency. Taken together, these results suggest variation in both temperature and water availability across the range shape multivariate adaptive traits in poplar.

Connecting overwintering success of eastern larch beetle to health of tamarack. Chapter 16

Science.gov (United States)

Robert C. Venette; Abigail J. Walter

2012-01-01

Michigan, Wisconsin, Maine, and Minnesota have experienced extensive mortality of tamarack (eastern larch) (Larix laricina). The Minnesota Department of Natural Resources reported tamarack mortality on 54,000 acres of Minnesota forests between 2001 and 2006 (Minnesota Department of Natural Resources 2006). Although the exact cause of tree mortality...

Oleoresin crystallization in eastern white pine: relationships with chemical components of cortical oleoresin and resistance to the white-pine weevil

Science.gov (United States)

Ronald C. Wilkinson

1979-01-01

Natural and weevil-larva-induced crystallization of oleoresin from 45 eastern white pine trees with known resin acid and monoterpene composition, and from 59 pairs of nonweeviled and heavily weeviled trees from the same seed sources, was examined in mid- and late spring. Very little difference was found between larva-induced and natural crystallization. Strobic acid-...

Variation in experimental flood impacts and ecogeomorphic feedbacks among native and exotic riparian tree seedlings

Science.gov (United States)

Kui, L.; Stella, J. C.; Skorko, K.; Lightbody, A.; Wilcox, A. C.; Bywater-Reyes, S.

2012-12-01

Flooding interacts with riparian plants on a variety of scales, resulting in coevolution of geomorphic surfaces with plant vegetation communities. Our research aims to develop a mechanistic understanding of riparian seedling damage from small floods, with a focus on differential responses among species (native and non-native), ecogeomorphic feedbacks, and implications for riparian restoration. We tested the effects of controlled flood events on cottonwood (Populus fremontii) and tamarisk (Tamarix spp.) seedlings in an experimental meandering stream channel. We hypothesized that seedling dislodgement and burial would be influenced by individual plant height, species-specific morphology, patch density, and differences in hydraulic forces (as a function of location on the bar). Four experimental floods were tested, with different combinations of plant species and seedling densities. For each flood run, rooted seedlings were installed within a 1.5-m-wide sandbar during low flow conditions and stream discharge was increased to a constant flood level for approximately 8 hours, after which seedling response was assessed. Seedling damage was analyzed within a logistic regression framework that predicted the probability of dislodgement or burial as a function of the explanatory variables. Plant dislodgement depended on root length and the location on the sandbar, whereas burial depended on plant height, species-specific morphology, and location. For every centimeter increase in plant height, the odds of plant burial decreased by 10 percent, illustrating the rate at which plants developed flood resistance as they grow taller. With every meter closer to the thalweg, plant dislodgement was four times more likely, and plant burial was 2.6 times more likely. The probability of burial was twice as great for tamarisk seedlings as for cottonwood. The increased sedimentation within tamarisk patches was associated with a denser foliage and a more compact crown for this species. The

Alsophila weidenbrueckii (Cyatheaceae), a new scaly tree fern from Papua New Guinea

NARCIS (Netherlands)

Lehnert, M.

2016-01-01

The scaly tree fern Alsophila weidenbrueckii is described and illustrated as new to science. It occurs in the Bismarck range in north-eastern New Guinea at 1200–2100 m in evergreen wet mountain forest. The species reaches maturity at a comparatively old age and large size and regenerates only in

Differential Consumption of Eastern Red Cedar (Juniperus virginiana) by Avian and Mammalian Guilds: Implications for Tree Invasion

Science.gov (United States)

Increased abundance of eastern redcedar (Juniperus virginianus), a native but invasive species in the Great Plains, has been associated with changes in ecosystem functioning and landscape cover. Knowledge of the main consumers and dispersal agents of eastern redcedar fruits is e...

Characterization of cytokinin signaling and homeostasis gene families in two hardwood tree species: Populus trichocarpa and Prunus persica.

Science.gov (United States)

Immanen, Juha; Nieminen, Kaisa; Duchens Silva, Héctor; Rodríguez Rojas, Fernanda; Meisel, Lee A; Silva, Herman; Albert, Victor A; Hvidsten, Torgeir R; Helariutta, Ykä

2013-12-16

Through the diversity of cytokinin regulated processes, this phytohormone has a profound impact on plant growth and development. Cytokinin signaling is involved in the control of apical and lateral meristem activity, branching pattern of the shoot, and leaf senescence. These processes influence several traits, including the stem diameter, shoot architecture, and perennial life cycle, which define the development of woody plants. To facilitate research about the role of cytokinin in regulation of woody plant development, we have identified genes associated with cytokinin signaling and homeostasis pathways from two hardwood tree species. Taking advantage of the sequenced black cottonwood (Populus trichocarpa) and peach (Prunus persica) genomes, we have compiled a comprehensive list of genes involved in these pathways. We identified genes belonging to the six families of cytokinin oxidases (CKXs), isopentenyl transferases (IPTs), LONELY GUY genes (LOGs), two-component receptors, histidine containing phosphotransmitters (HPts), and response regulators (RRs). All together 85 Populus and 45 Prunus genes were identified, and compared to their Arabidopsis orthologs through phylogenetic analyses. In general, when compared to Arabidopsis, differences in gene family structure were often seen in only one of the two tree species. However, one class of genes associated with cytokinin signal transduction, the CKI1-like family of two-component histidine kinases, was larger in both Populus and Prunus than in Arabidopsis.

Influence of Inter stock Grafting as a Dwarfing Component on Peach Trees Development and Fruit Quality

International Nuclear Information System (INIS)

Hossain, S.; Nasrulhaq, A.; Mizutani, F.

2006-01-01

A field experiment was conducted to investigate the interstock grafting effect as a dwarfing component on Peach tree development and fruit quality. The study was made at the Ehime University Experimental farm located in south-eastern Japan during the period 2001-2005. The results of the field experiment indicated that pruned branches weight and flowers number were lower in interstock than in control trees. However, percent fruit set was a little higher in intersrock treated than in control trees. Fruit yield and fruit weight were lower in interstock treated than control trees. Soluble solids content and maturity index were higher in interstock treated trees than control, with an increasing trend in the period from 2001 to 2005, while titratable acidity showed that the livestock grafting is a useful dwarfing component for controlling the size of peach trees and improvement of fruit quality. (author)

Functional Traits and Water Transport Strategies in Lowland Tropical Rainforest Trees

Science.gov (United States)

Apgaua, Deborah M. G.; Ishida, Françoise Y.; Tng, David Y. P.; Laidlaw, Melinda J.; Santos, Rubens M.; Rumman, Rizwana; Eamus, Derek; Holtum, Joseph A. M.; Laurance, Susan G. W.

2015-01-01

Understanding how tropical rainforest trees may respond to the precipitation extremes predicted in future climate change scenarios is paramount for their conservation and management. Tree species clearly differ in drought susceptibility, suggesting that variable water transport strategies exist. Using a multi-disciplinary approach, we examined the hydraulic variability in trees in a lowland tropical rainforest in north-eastern Australia. We studied eight tree species representing broad plant functional groups (one palm and seven eudicot mature-phase, and early-successional trees). We characterised the species’ hydraulic system through maximum rates of volumetric sap flow and velocities using the heat ratio method, and measured rates of tree growth and several stem, vessel, and leaf traits. Sap flow measures exhibited limited variability across species, although early-successional species and palms had high mean sap velocities relative to most mature-phase species. Stem, vessel, and leaf traits were poor predictors of sap flow measures. However, these traits exhibited different associations in multivariate analysis, revealing gradients in some traits across species and alternative hydraulic strategies in others. Trait differences across and within tree functional groups reflect variation in water transport and drought resistance strategies. These varying strategies will help in our understanding of changing species distributions under predicted drought scenarios. PMID:26087009

Functional Traits and Water Transport Strategies in Lowland Tropical Rainforest Trees.

Directory of Open Access Journals (Sweden)

Deborah M G Apgaua

Full Text Available Understanding how tropical rainforest trees may respond to the precipitation extremes predicted in future climate change scenarios is paramount for their conservation and management. Tree species clearly differ in drought susceptibility, suggesting that variable water transport strategies exist. Using a multi-disciplinary approach, we examined the hydraulic variability in trees in a lowland tropical rainforest in north-eastern Australia. We studied eight tree species representing broad plant functional groups (one palm and seven eudicot mature-phase, and early-successional trees. We characterised the species' hydraulic system through maximum rates of volumetric sap flow and velocities using the heat ratio method, and measured rates of tree growth and several stem, vessel, and leaf traits. Sap flow measures exhibited limited variability across species, although early-successional species and palms had high mean sap velocities relative to most mature-phase species. Stem, vessel, and leaf traits were poor predictors of sap flow measures. However, these traits exhibited different associations in multivariate analysis, revealing gradients in some traits across species and alternative hydraulic strategies in others. Trait differences across and within tree functional groups reflect variation in water transport and drought resistance strategies. These varying strategies will help in our understanding of changing species distributions under predicted drought scenarios.

Functional Traits and Water Transport Strategies in Lowland Tropical Rainforest Trees.

Science.gov (United States)

Apgaua, Deborah M G; Ishida, Françoise Y; Tng, David Y P; Laidlaw, Melinda J; Santos, Rubens M; Rumman, Rizwana; Eamus, Derek; Holtum, Joseph A M; Laurance, Susan G W

2015-01-01

Understanding how tropical rainforest trees may respond to the precipitation extremes predicted in future climate change scenarios is paramount for their conservation and management. Tree species clearly differ in drought susceptibility, suggesting that variable water transport strategies exist. Using a multi-disciplinary approach, we examined the hydraulic variability in trees in a lowland tropical rainforest in north-eastern Australia. We studied eight tree species representing broad plant functional groups (one palm and seven eudicot mature-phase, and early-successional trees). We characterised the species' hydraulic system through maximum rates of volumetric sap flow and velocities using the heat ratio method, and measured rates of tree growth and several stem, vessel, and leaf traits. Sap flow measures exhibited limited variability across species, although early-successional species and palms had high mean sap velocities relative to most mature-phase species. Stem, vessel, and leaf traits were poor predictors of sap flow measures. However, these traits exhibited different associations in multivariate analysis, revealing gradients in some traits across species and alternative hydraulic strategies in others. Trait differences across and within tree functional groups reflect variation in water transport and drought resistance strategies. These varying strategies will help in our understanding of changing species distributions under predicted drought scenarios.

Analysis of harvesting opportunities for thinning eastern hardwoods on steep terrain

Science.gov (United States)

Chris B. LeDoux; John E. Baumgras

1988-01-01

Harvesting cost and revenue models were used to evaluate yarding costs by yarder type and to compare stump-to-mill harvesting costs to revenues available from multiproduct thinnings in eastern hardwoods. This analysis includes six types of cable yarders and thinnings in stands where the average diameter at breast height of trees harvested ranged from 7 to 12 inches. To...

Study of the transfer of radionuclides in trees at a forest site

International Nuclear Information System (INIS)

Barci-Funel, G.; Dalmasso, J.; Barci, V.L.; Ardisson, G.

1995-01-01

The transfer of radionuclides such as 137 Cs and 90 Sr from soil to trees (conifers) was studied in a forest area, the Boreon massif, 30 km north of Nice in South Eastern France. This area has been highly contaminated after the Chernobyl accident. Besides the γ-emitting fission products, the α-emitters 238 Pu and 239+240 Pu and the pure β-emitter 90 Sr were measured in different parts of the studied trees (roots, branches, twigs, etc.). As has already been reported by other authors, the radionuclide activities in the tree rings are not correlated with the fallout deposition. They were found varying according to the sap flux in the tree and higher in sapwood than in heartwood. For cesium the root absorption was found to be lower than the atmospheric deposition. Soil-to-plant concentration factors were calculated for 137 Cs, 90 Sr and 239+240 Pu

PHYTOREMEDIATION OF GROUNDWATER AT AIR FORCE PLANT 4, CARSWELL, TEXAS - INNOVATIVE TECHNOLOGY EVALUATION REPORT (CD-ROM)

Science.gov (United States)

Over 600 Cottonwood trees were planted over a shallow groundwater plume in an attempt to detoxify the tricWoroethylene (TCE) in a groundwater plume at a former Air Force facility. Two planting techniques were used: rooted stock about two years old, and 18 inch cuttings were insta...

PHYTOREMEDIATION OF GROUNDWATER AT AIR FORCE PLANT 4, CARSWELL, TEXAS - INNOVATIVE TECHNOLOGY EVALUATION REPORT

Science.gov (United States)

Over 600 Cottonwood trees were planted over a shallow groundwater plume in an attempt to detoxify the trichloroethylene (TCE) in a groundwater plume at a former Air Force facility. Two planting techniques were used: rooted stock about two years old, and 18 inch cuttings were inst...

Modeling Phosphorus Capture by Plants Growing in a Multispecies Riparian Buffer

Directory of Open Access Journals (Sweden)

J. M. Kelly

2012-01-01

Full Text Available The NST 3.0 mechanistic nutrient uptake model was used to explore P uptake to a depth of 120 cm over a 126 d growing season in simulated buffer communities composed of mixtures of cottonwood (Populus deltoids Bartr., switchgrass (Panicum virgatum L., and smooth brome (Bromus inermis Leyss. Model estimates of P uptake from pure stands of smooth brome and cottonwood were 18.9 and 24.5 kg ha−1, respectively. Uptake estimates for mixed stands of trees and grasses were intermediate to pure stands. A single factor sensitivity analysis of parameters used to calculate P uptake for each cover type indicated that Imax, k, ro, and Lo were consistently the most responsive to changes ranging from −50% to +100%. Model exploration of P uptake as a function of soil depth interval indicated that uptake was highest in the 0–30 cm intervals, with values ranging from 85% of total for cottonwood to 56% for switchgrass.

Comparison of saproxylic beetle assemblages on four different broad-leaved tree species in south-eastern Sweden

OpenAIRE

Johansson, Helena

2011-01-01

Old hollow trees have declined in Europe and many saproxylic (wood-dwelling) beetles dependent on them are threatened. Several studies have been done on old hollow oaks and they have been shown to harbour a species-rich saproxylic beetle fauna. However, other broad-leaved trees might also be important to consider as supporting habitats. The aim of this study was to investigate to what extent saproxylic beetles are tree genus specialists. Pitfall traps and window traps were used to compare the...

A vegetation map for eastern Africa

DEFF Research Database (Denmark)

Lillesø, Jens-Peter Barnekow; van Breugel, Paulo; Graudal, Lars

2015-01-01

The potential natural vegetation (PNV) map of eastern and southern Africa covers the countries Burundi, Ethiopia, Kenya, Uganda, Rwanda, Tanzania, and Zambia. The first version of the map was developed by various partners in East Africa and Europe in 2010 and has now reached version 2. The map...... is available in different formats and is accompanied by an extensive documentation of the floristic, physiognomic and other characteristics of the different vegetation types and useful woody species in the 8 countries. It is complemented by a species selection tool, which can be used to 'find the right tree...

Pyrolysis and Combustion Kinetics of Raw and Carbonized Cottonwood and Switchgrass Agroforests

Directory of Open Access Journals (Sweden)

Sammy Sadaka

2015-06-01

Full Text Available Raw biomass is not commonly suitable as feedstock for existing power plants, mainly because of the substantial required infrastructural changes. As a result, most raw feedstock requires pre-treatment to improve its physical and thermal characteristics. Biomass carbonization is one of the pre-treatments that produces charcoal-like feedstock. This paper explores the effects of the carbonization process on the physiochemical characteristics of biomass produced from two cottonwood clones, S7C20 and ST66, and switchgrass (var. Alamo. Additionally, it studies the thermal degradation kinetics of raw and carbonized agroforestry products in nitrogen and air environments. Feedstock samples were carbonized in a batch reactor at 400 °C in an oxygen-free environment for 2 hours. Carbonization decreased biomass bulk density, moisture content, and volatile solids while increasing fixed carbon, ash content, pH, and heating values. The heating value of S7C20, ST66, and switchgrass increased by 58.6%, 60.3%, and 69.7%, respectively. Carbonization increased the activation energy values under the condition of pyrolysis and decreased these values under the condition of combustion. The carbonization process produced a charcoal-like feedstock that may be processed with coal or even replace it.

The effect of gamma irradiation on in vitro digestible energy of some agricultural residues

International Nuclear Information System (INIS)

Al-Masri, M.R.

1993-03-01

Experiments have been carried out on the effect of gamma irradiation on total energy, dry organic matter digestibility and on digestible energy of organic matter for some agricultural residues (maize straw, lentils straw, cottonwood, residues of apple-tree pruning, olive-cake first and second treatment). Sample were irradiated at 0, 50 and 100 KGy. Total energy was estimated by calorimeter. Digestibility was estimated in vitro by the method of Tilly and Terry (1963). Two sheep with rumen fistula were used as rumen liquor donating animals. Irradiation resulted in increasing the digestion of organic and dry matter and also the digestible energy of organic matter in all residues used except lentils straw and olive-cake first treatment. The increase in digestible energy values of organic matter (kJ) at dose of 100 KGy were: 155, 105, 71 and 25 for residue of apple-tree pruning, maize straw, cottonwood and olive-cake second treatment, respectively. (author).28 refs., 10 figs., 5 tabs

Changes in composition, structure and aboveground biomass over seventy-six years (1930-2006) in the Black Rock Forest, Hudson Highlands, southeastern New York State.

Science.gov (United States)

Schuster, W S F; Griffin, K L; Roth, H; Turnbull, M H; Whitehead, D; Tissue, D T

2008-04-01

We sought to quantify changes in tree species composition, forest structure and aboveground forest biomass (AGB) over 76 years (1930-2006) in the deciduous Black Rock Forest in southeastern New York, USA. We used data from periodic forest inventories, published floras and a set of eight long-term plots, along with species-specific allometric equations to estimate AGB and carbon content. Between the early 1930s and 2000, three species were extirpated from the forest (American elm (Ulmus americana L.), paper birch (Betula papyrifera Marsh.) and black spruce (Picea mariana (nigra) (Mill.) BSP)) and seven species invaded the forest (non-natives tree-of-heaven (Ailanthus altissima (Mill.) Swingle) and white poplar (Populus alba L.) and native, generally southerly distributed, southern catalpa (Catalpa bignonioides Walt.), cockspur hawthorn (Crataegus crus-galli L.), red mulberry (Morus rubra L.), eastern cottonwood (Populus deltoides Bartr.) and slippery elm (Ulmus rubra Muhl.)). Forest canopy was dominated by red oak and chestnut oak, but the understory tree community changed substantially from mixed oak-maple to red maple-black birch. Density decreased from an average of 1500 to 735 trees ha(-1), whereas basal area doubled from less than 15 m(2) ha(-1) to almost 30 m(2) ha(-1) by 2000. Forest-wide mean AGB from inventory data increased from about 71 Mg ha(-1) in 1930 to about 145 Mg ha(-1) in 1985, and mean AGB on the long-term plots increased from 75 Mg ha(-1) in 1936 to 218 Mg ha(-1) in 1998. Over 76 years, red oak (Quercus rubra L.) canopy trees stored carbon at about twice the rate of similar-sized canopy trees of other species. However, there has been a significant loss of live tree biomass as a result of canopy tree mortality since 1999. Important constraints on long-term biomass increment have included insect outbreaks and droughts.

The role of on-farm trees as an adaptation strategy to climate ...

African Journals Online (AJOL)

A study was conducted to investigate the role of on-farm tree as a long-term and sustainable adaptation strategy to climatic stresses in eight villages around Mkingu Nature Forest Reserve (MkNFR) in the. Eastern Arc Mountains of Tanzania. Specifically, the effects of climate change to peoples' livelihoods and the role of ...

Tree species effects on calcium cycling: The role of calcium uptake in deep soils

NARCIS (Netherlands)

Dijkstra, F.A.; Smits, M.M.

2002-01-01

Soil acidity and calcium (Ca) availability in the surface soil differ substantially beneath sugar maple (Acer saccharum) and eastern hemlock (Tsuga canadensis) trees in a mixed forest in northwestern Connecticut. We determined the effect of pumping of Ca from deep soil (rooting zone below 20-cm

Ethylene and Carbon Monoxide Production by Septoria musiva

Science.gov (United States)

S. Brown-Skrobot; L. R. Brown; T. H. Filer

1984-01-01

An investigation into the mechanism by which Septoria musiva causes the premature defoliation of cottonwood trees was undertaken. Gas-chromatograpic analysis of the atmosphere overlying the original culture indicated that this fungus produced significant quantities of ethylene and carbon monoxide. Subcultures failed to produce either gas on a variety...

Synergistic effects of drought and deforestation on the resilience of the south-eastern Amazon rainforest

NARCIS (Netherlands)

Staal, A.; Dekkers, S.; Hirota Magalhaes, M.; Nes, van E.H.

2015-01-01

The south-eastern Amazon rainforest is subject to ongoing deforestation and is expected to become drier due to climate change. Recent analyses of the distribution of tree cover in the tropics show three modes that have been interpreted as representing alternative stable states: forest, savanna and

Specific Gravity Variation in a Lower Mississippi Valley Cottonwood Population

Science.gov (United States)

R. E. Farmer; J. R. Wilcox

1966-01-01

Specific gravity varied from 0,32 to 0.46, averaging 0.38. Most of the variation was associated with individual trees; samples within locations accounted for a smaller, but statistically significant, portion of the variation. Variation between locatians was not significant. It was concluded that individual high-density trees' should be sought throughout the...

Stump-to-mill timber production cost equations for cable logging eastern hardwoods

Science.gov (United States)

Chris B. LeDoux; Chris B. LeDoux

1985-01-01

Logging cost simulators and data from logging cost studies have been assembled and converted into a series of equations that can be used to estimate the stump-to-mill cost of cable logging in mountainous terrain in the Eastern United States. These equations include the use of two small and four mediumsize cable yarders and are appropriate for harvested trees ranging in...

400 years of summer climatic conditions in the N Carpathian Mts. (eastern Europe) based on O and C stable isotopes in Pinus Cembra L tree rings

Science.gov (United States)

Nagavciuc, Viorica; Popa, Ionel; Kern, Zoltán; Persoiu, Aurel

2016-04-01

For a better understanding of how the climate is changing and how the environment responds to these changes, it is necessary to understand how the climate has varied in the past. Romania's virgin forests have a great potential to obtain long tree-ring chronologies with annual resolution; but so far, only a few studies resulted in quantitative paleoclimatic reconstructions. In this context, the aim of this study is 1) to calibrate the relationship between the stable isotopes of oxygen and carbon in tree rings and the main climatic parameters and determine the potential of Pinus cembra (Cǎlimani Mts., N Romania, Eastern Europe) for paleoclimatic reconstructions; 2) to provide the first palaeoclimatic reconstitution in Romania based on the isotopic composition of oxygen and carbon in tree ring cellulose, and 3) to test the hypothesis that nearby sulphur mines have not altered the climatic signal recorded by the stable isotopic composition of tree rings, contrary to the similar signal recorded by TRW. For this study, we have analysed wood samples of Swiss stone pine (Pinus cembra L.) from living and dead trees from Cǎlimani Mts., NE Romania, aged between 1600 and 2012 AD. The isotopic composition of oxygen and carbon from the cellulose was analysed at the Institute for Geological and Geochemical Research, Budapest, Hungary, using a high-temperature pyrolysis system (Thermo Quest TC-EA) coupled to an isotope ratio mass spectrometer (Thermo Finningan Delta V) following a ring by ring (i.e., non-pooled) approach. The average level of δ18O and δ13C in cellulose for the period 1600-2012 was 28.83‰ and -22.63 ‰. The tree ring cellulose δ18O and δ13C values showed a strong positive correlation with maximum air temperature (r = 0.6 for δ18O and r = 0.5 for δ13C), mean temperature (r = 0.6 for δ18O and r = 0.45 for δ13C), and sunshine duration (r = 0.69 for δ18O) and negatively correlated with precipitation amount (r = -0.5 for δ18O and r = 0.3 for δ13C) and

Quantifying environmental limiting factors on tree cover using geospatial data.

Science.gov (United States)

Greenberg, Jonathan A; Santos, Maria J; Dobrowski, Solomon Z; Vanderbilt, Vern C; Ustin, Susan L

2015-01-01

Environmental limiting factors (ELFs) are the thresholds that determine the maximum or minimum biological response for a given suite of environmental conditions. We asked the following questions: 1) Can we detect ELFs on percent tree cover across the eastern slopes of the Lake Tahoe Basin, NV? 2) How are the ELFs distributed spatially? 3) To what extent are unmeasured environmental factors limiting tree cover? ELFs are difficult to quantify as they require significant sample sizes. We addressed this by using geospatial data over a relatively large spatial extent, where the wall-to-wall sampling ensures the inclusion of rare data points which define the minimum or maximum response to environmental factors. We tested mean temperature, minimum temperature, potential evapotranspiration (PET) and PET minus precipitation (PET-P) as potential limiting factors on percent tree cover. We found that the study area showed system-wide limitations on tree cover, and each of the factors showed evidence of being limiting on tree cover. However, only 1.2% of the total area appeared to be limited by the four (4) environmental factors, suggesting other unmeasured factors are limiting much of the tree cover in the study area. Where sites were near their theoretical maximum, non-forest sites (tree cover demand, and closed-canopy forests were not limited by any particular environmental factor. The detection of ELFs is necessary in order to fully understand the width of limitations that species experience within their geographic range.

Inferring biome-scale net primary productivity from tree-ring isotopes

Science.gov (United States)

Pederson, N.; Levesque, M.; Williams, A. P.; Hobi, M. L.; Smith, W. K.; Andreu-Hayles, L.

2017-12-01

Satellite estimates of vegetation growth (net primary productivity; NPP), tree-ring records, and forest inventories indicate that ongoing climate change and rising atmospheric CO2 concentration are altering productivity and carbon storage of forests worldwide. The impact of global change on the trends of NPP, however, remain unknown because of the lack of long-term high-resolution NPP data. For the first time, we tested if annually resolved carbon (δ13C) and oxygen (δ18O) stable isotopes from the cellulose of tree rings from trees in temperate regions could be used as a tool for inferring NPP across spatiotemporal scales. We compared satellite NPP estimates from the moderate-resolution imaging spectroradiometer sensor (MODIS, product MOD17A) and a newly developed global NPP dataset derived from the Global Inventory Modeling and Mapping Studies (GIMMS) dataset to annually resolved tree-ring width and δ13C and δ18O records from four sites along a hydroclimatic gradient in Eastern and Central United States. We found strong correlations across large geographical regions between satellite-derived NPP and tree-ring isotopes that ranged from -0.40 to -0.91. Notably, tree-ring derived δ18O had the strongest relation to climate. The results were consistent among the studied tree species (Quercus rubra and Liriodendron tulipifera) and along the hydroclimatic conditions of our network. Our study indicates that tree-ring isotopes can potentially be used to reconstruct NPP in time and space. As such, our findings represent an important breakthrough for estimating long-term changes in vegetation productivity at the biome scale.

Human management and landscape changes at Palaikastro (Eastern Crete) from the Late Neolithic to the Early Minoan period

Science.gov (United States)

Cañellas-Boltà, N.; Riera-Mora, S.; Orengo, H. A.; Livarda, A.; Knappett, C.

2018-03-01

On the east Mediterranean island of Crete, a hierarchical society centred on large palatial complexes emerges during the Bronze Age. The economic basis for this significant social change has long been debated, particularly concerning the role of olive cultivation in the island's agricultural system. With the aim of studying vegetation changes and human management to understand the landscape history from Late Neolithic to Bronze Age, two palaeoenvironmental records have been studied at Kouremenos marsh, near the site of Palaikastro (Eastern Crete). Pollen, NPP and charcoal particles analyses evidenced seven phases of landscape change, resulting from different agricultural and pastoral practices and the use of fire probably to manage vegetation. Moreover, the Kouremenos records show the importance of the olive tree in the area. They reflect a clear trend for its increasing use and exploitation from 3600 cal yr BC (Final Neolithic) to the Early Minoan period, that is coeval with an opening of the landscape. The increase of Olea pollen was due to the expansion of the tree and its management using pruning and mechanical cleaning. The onset of olive expansion at c. 3600 cal yr BC places Crete among the first locales in the eastern Mediterranean in the management of this tree. Between c. 2780 and 2525 cal yr BC the landscape was largely occupied by olive and grasslands, coinciding with an increase in grazing practices. The high Olea pollen percentages (40-45%) suggest an intensive and large-scale exploitation of the olive tree. The results suggest that a complex and organized landscape with complementary land uses and activities was already in place since the Final Neolithic. The notable expansion of olive trees suggests the relevance of olive exploitation in the socio-economic development of Minoan towns of eastern Crete. Other crops, such as cereals and vine, and activities such as grazing have also played an important role in the configuration of the past landscape.

Modelling effects of tree population dynamics, tree throw and pit-mound formation/diffusion on microtopography over time in different forest settings

Science.gov (United States)

Martin, Y. E.; Johnson, E. A.; Gallaway, J.; Chaikina, O.

2011-12-01

Herein we conduct a followup investigation to an earlier research project in which we developed a numerical model of tree population dynamics, tree throw, and sediment transport associated with the formation of pit-mound features for Hawk Creek watershed, Canadian Rockies (Gallaway et al., 2009). We extend this earlier work by exploring the most appropriate transport relations to simulate the diffusion over time of newly-formed pit-pound features due to tree throw. We combine our earlier model with a landscape development model that can incorporate these diffusive transport relations. Using these combined models, changes in hillslope microtopography over time associated with the formation of pit-mound features and their decay will be investigated. The following ideas have motivated this particular study: (i) Rates of pit-mound degradation remain a source of almost complete speculation, as there is almost no long-term information on process rates. Therefore, we will attempt to tackle the issue of pit-mound degradation in a methodical way that can guide future field studies; (ii) The degree of visible pit-mound topography at any point in time on the landscape is a joint function of the rate of formation of new pit-mound features due to tree death/topple and their magnitude vs. the rate of decay of pit-mound features. An example of one interesting observation that arises is the following: it appears that pit-mound topography is often more pronounced in some eastern North American forests vs. field sites along the eastern slopes of the Canadian Rockies. Why is this the case? Our investigation begins by considering whether pit-mound decay might occur by linear or nonlinear diffusion. What differences might arise depending on which diffusive approach is adopted? What is the magnitude of transport rates associated with these possible forms of transport relations? We explore linear and nonlinear diffusion at varying rates and for different sizes of pit-mound pairs using a

Radionuclides in a deciduous forest surrounding a shallow-land-burial site in the eastern United States

International Nuclear Information System (INIS)

Rickard, W.H.; Kirby, L.J.; McShane, M.C.

1981-06-01

The objective of this study was to determine if radioactive materials buried in trenches at the Maxey Flats burial ground in eastern Kentucky have migrated into the surrounding oak-hickory forest. Forest floor litter, minearl soil, and tree leaves were sampled and the radionuclide content measured

Imidacloprid movement in soils and impacts on soil microarthropods in southern Appalachian eastern hemlock stands

Science.gov (United States)

Jennifer D. Knoepp; James M. Vose; Jerry L. Michael; Barbara C. Reynolds

2012-01-01

Imidacloprid is a systemic insecticide effective in controlling the exotic pest Adelges tsugae (hemlock woolly adelgid) in eastern hemlock (Tsuga canadensis) trees. Concerns over imidacloprid impacts on nontarget species have limited its application in southern Appalachian ecosystems. We quantified the movement and adsorption of imidacloprid in forest soils after soil...

The effects of urban warming on herbivore abundance and street tree condition.

Directory of Open Access Journals (Sweden)

Adam G Dale

Full Text Available Trees are essential to urban habitats because they provide services that benefit the environment and improve human health. Unfortunately, urban trees often have more herbivorous insect pests than rural trees but the mechanisms and consequences of these infestations are not well documented. Here, we examine how temperature affects the abundance of a scale insect, Melanaspis tenebricosa (Comstock (Hemiptera: Diaspididae, on one of the most commonly planted street trees in the eastern U.S. Next, we examine how both pest abundance and temperature are associated with water stress, growth, and condition of 26 urban street trees. Although trees in the warmest urban sites grew the most, they were more water stressed and in worse condition than trees in cooler sites. Our analyses indicate that visible declines in tree condition were best explained by scale-insect infestation rather than temperature. To test the broader relevance of these results, we extend our analysis to a database of more than 2700 Raleigh, US street trees. Plotting these trees on a Landsat thermal image of Raleigh, we found that warmer sites had over 70% more trees in poor condition than those in cooler sites. Our results support previous studies linking warmer urban habitats to greater pest abundance and extend this association to show its effect on street tree condition. Our results suggest that street tree condition and ecosystem services may decline as urban expansion and global warming exacerbate the urban heat island effect. Although our non-probability sampling method limits our scope of inference, our results present a gloomy outlook for urban forests and emphasize the need for management tools. Existing urban tree inventories and thermal maps could be used to identify species that would be most suitable for urban conditions.

Odor-baited trap trees: a novel management tool for plum curculio (Coleoptera: Curculionidae).

Science.gov (United States)

Leskey, Tracy C; Piñero, Jaime C; Prokopy, Ronald J

2008-08-01

The plum curculio, Conotrachelus nenuphar (Herbst) (Coleoptera: Curculionidae), one of the most important pests of apple (Malus spp.) in eastern and central North America, historically has been managed in New England apple orchards by three full block insecticide applications. Efforts to reduce insecticide inputs against plum curculio include perimeter row sprays, particularly after petal fall, to control immigrating adults. The odor-baited trap tree approach represents a new reduced input strategy for managing plum curculio based on the application of insecticides to a few perimeter-row trap trees rather than the entire perimeter row or full orchard block. Here, we compared the efficacy of a trap tree approach with perimeter row treatments to manage populations after petal fall in commercial apple orchards in 2005 and 2006. Injury was significantly greater in trap trees compared with unbaited perimeter row treated trees in both years of the study. In 2005, heavy rains prevented growers from applying insecticide applications at regular intervals resulting in high injury in nearly all blocks regardless of type of management strategy. In 2006, both the trap-tree and perimeter-row treatments prevented penetration by immigrating populations and resulted in economically acceptable levels of injury. The trap tree management strategy resulted in a reduction of approximately 70% total trees being treated with insecticide compared with perimeter row sprays and 93% compared with standard full block sprays.

Abundance of large old trees in wood-pastures of Transylvania (Romania).

Science.gov (United States)

Hartel, Tibor; Hanspach, Jan; Moga, Cosmin I; Holban, Lucian; Szapanyos, Árpád; Tamás, Réka; Hováth, Csaba; Réti, Kinga-Olga

2018-02-01

Wood-pastures are special types of agroforestry systems that integrate trees with livestock grazing. Wood pastures can be hotspots for large old tree abundance and have exceptional natural values; but they are declining all over Europe. While presence of large old trees in wood-pastures can provide arguments for their maintenance, actual data on their distribution and abundance are sparse. Our study is the first to survey large old trees in Eastern Europe over such a large area. We surveyed 97 wood-pastures in Transylvania (Romania) in order to (i) provide a descriptive overview of the large old tree abundance; and (ii) to explore the environmental determinants of the abundance and persistence of large old trees in wood-pastures. We identified 2520 large old trees belonging to 16 taxonomic groups. Oak was present in 66% of the wood-pastures, followed by beech (33%), hornbeam (24%) and pear (22%). For each of these four species we constructed a generalized linear model with quasi-Poisson error distribution to explain individual tree abundance. Oak trees were most abundant in large wood-pastures and in wood-pastures from the Saxon cultural region of Transylvania. Beech abundance related positively to elevation and to proximity of human settlements. Abundance of hornbeam was highest in large wood-pastures, in wood-pastures from the Saxon cultural region, and in places with high cover of adjacent forest and a low human population density. Large old pear trees were most abundant in large wood-pastures that were close to paved roads. The maintenance of large old trees in production landscapes is a challenge for science, policy and local people, but it also can serve as an impetus for integrating economic, ecological and social goals within a landscape. Copyright © 2017 Elsevier B.V. All rights reserved.

Quantifying environmental limiting factors on tree cover using geospatial data.

Directory of Open Access Journals (Sweden)

Jonathan A Greenberg

Full Text Available Environmental limiting factors (ELFs are the thresholds that determine the maximum or minimum biological response for a given suite of environmental conditions. We asked the following questions: 1 Can we detect ELFs on percent tree cover across the eastern slopes of the Lake Tahoe Basin, NV? 2 How are the ELFs distributed spatially? 3 To what extent are unmeasured environmental factors limiting tree cover? ELFs are difficult to quantify as they require significant sample sizes. We addressed this by using geospatial data over a relatively large spatial extent, where the wall-to-wall sampling ensures the inclusion of rare data points which define the minimum or maximum response to environmental factors. We tested mean temperature, minimum temperature, potential evapotranspiration (PET and PET minus precipitation (PET-P as potential limiting factors on percent tree cover. We found that the study area showed system-wide limitations on tree cover, and each of the factors showed evidence of being limiting on tree cover. However, only 1.2% of the total area appeared to be limited by the four (4 environmental factors, suggesting other unmeasured factors are limiting much of the tree cover in the study area. Where sites were near their theoretical maximum, non-forest sites (tree cover < 25% were primarily limited by cold mean temperatures, open-canopy forest sites (tree cover between 25% and 60% were primarily limited by evaporative demand, and closed-canopy forests were not limited by any particular environmental factor. The detection of ELFs is necessary in order to fully understand the width of limitations that species experience within their geographic range.

13C trend in an Egyptian recent tree as a record for global carbon dioxide behaviour

International Nuclear Information System (INIS)

Aly, A.I.M.; Belacy, N.; Abou El-Nour, F.

1988-01-01

The record of the 13 C content in tree rings of an Egyptian tree is used as indication for the increase of the atmospheric carbon dioxide concentration. A decrease of the 13 C isotopic content of the tree rings is observed starting from 1940 coinciding with a significant increase in the global production of CO 2 due to combustion of fossil fuel depleted in 13 C with respect to the atmosphere. Considering the local as well as the global CO 2 production rates together with the measured isotopic data, it may be concluded that the behaviour of carbon dioxide in the investigated Eastern Delta province in Egypt reflects mainly a global rather than a local effect. (author)

Abundance and population structure of eastern worm snakes in forest stands with various levels of overstory tree retention

Science.gov (United States)

Zachary I. Felix; Yong Wang; Callie Jo Schweitzer

2010-01-01

In-depth analyses of a species’ response to canopy retention treatments can provide insight into reasons for observed changes in abundance. The eastern worm snake (Carphophis amoenus amoenus Say) is common in many eastern deciduous forests, yet little is known about the ecology of the species in managed forests. We examined the relationship between...

Characteristics of mangrove swamps managed for mosquito control in eastern Florida, USA

Science.gov (United States)

Middleton, B.; Devlin, D.; Proffitt, E.; McKee, K.; Cretini, K.F.

2008-01-01

Manipulations of the vegetation and hydrology of wetlands for mosquito control are common worldwide, but these modifications may affect vital ecosystem processes. To control mosquitoes in mangrove swamps in eastern Florida, managers have used rotational impoundment management (RIM) as an alternative to the worldwide practice of mosquito ditching. Levees surround RIM swamps, and water is pumped into the impoundment during the summer, a season when natural swamps have low water levels. In the New World, these mosquito-managed swamps resemble the mixed basin type of mangrove swamp (based on PCA analysis). An assessment was made of RIM, natural (control), and breached-RIM (restored) swamps in eastern Florida to compare their structural complexities, soil development, and resistance to invasion. Regarding structural complexity, dominant species composition differed between these swamps; the red mangrove Rhizophora mangle occurred at a higher relative density in RIM and breached-RIM swamps, and the black mangrove Avicennia germinans had a higher relative density in natural swamps. Tree density and canopy cover were higher and tree height lower in RIM swamps than in natural and breached-RIM swamps. Soil organic matter in RIM swamps was twice that in natural or breached-RIM swamps. RIM swamps had a lower resistance to invasion by the Brazilian pepper tree Schinus terebinthifolius, which is likely attributable to the lower porewater salinity in RIM swamps. These characteristics may reflect differences in important ecosystem processes (primary production, trophic structure, nutrient cycling, decomposition). Comparative assessments of managed wetlands are vital for land managers, so that they can make informed decisions compatible with conservation objectives. ?? Inter-Research 2008.

When a tree falls: Controls on wood decay predict standing dead tree fall and new risks in changing forests.

Science.gov (United States)

Oberle, Brad; Ogle, Kiona; Zanne, Amy E; Woodall, Christopher W

2018-01-01

When standing dead trees (snags) fall, they have major impacts on forest ecosystems. Snag fall can redistribute wildlife habitat and impact public safety, while governing important carbon (C) cycle consequences of tree mortality because ground contact accelerates C emissions during deadwood decay. Managing the consequences of altered snag dynamics in changing forests requires predicting when snags fall as wood decay erodes mechanical resistance to breaking forces. Previous studies have pointed to common predictors, such as stem size, degree of decay and species identity, but few have assessed the relative strength of underlying mechanisms driving snag fall across biomes. Here, we analyze nearly 100,000 repeated snag observations from boreal to subtropical forests across the eastern United States to show that wood decay controls snag fall in ways that could generate previously unrecognized forest-climate feedback. Warmer locations where wood decays quickly had much faster rates of snag fall. The effect of temperature on snag fall was so strong that in a simple forest C model, anticipated warming by mid-century reduced snag C by 22%. Furthermore, species-level differences in wood decay resistance (durability) accurately predicted the timing of snag fall. Differences in half-life for standing dead trees were similar to expected differences in the service lifetimes of wooden structures built from their timber. Strong effects of temperature and wood durability imply future forests where dying trees fall and decay faster than at present, reducing terrestrial C storage and snag-dependent wildlife habitat. These results can improve the representation of forest C cycling and assist forest managers by helping predict when a dead tree may fall.

Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region (Version 2.0)

Science.gov (United States)

2010-05-01

monophylla or P. edulis), junipers (Juniperus), cottonwoods (e.g., Populus fremontii), willows (Salix), or hardwoods (e.g., Quercus , Platanus...pine in association with incense cedar and California black oak ( Quercus kelloggii) on the western slopes and Jeffrey pine on the eastern slopes...corkbark fir (Abies lasiocarpa var. arizonica ), limber pine (Pinus flexilis), and bristlecone pine (P. aristata) (Bailey 1995). Black Hills (MLRA

Can nutrient limitations explain low and declining white spruce growth near the Arctic treeline in the eastern Brooks Range, Alaska?

Science.gov (United States)

Ellison, S.; Sullivan, P. F.

2014-12-01

The position of the Arctic treeline is of critical importance for global carbon cycling and surface energy budgets. However, controls on tree growth at treeline remain uncertain. In the Alaskan Brooks Range, 20th century warming has caused varying growth responses among treeline trees, with trees in the west responding positively, while trees in the east have responded negatively. The prevailing explanation of this trend ascribes the negative growth response to warming-induced drought stress in the eastern Brooks Range. However, recent measurements of carbon isotope discrimination in tree rings, xylem sap flow and needle gas exchange suggest that drought stress cannot explain these regional growth declines. Additionally, evidence from the western Brooks Range suggests that nutrient availability, rather than drought stress, may be the proximate control on tree growth. In this study, we investigated the hypothesis that low and declining growth of eastern Brooks Range trees is due to low and declining soil nutrient availability, which may continue to decrease with climate change as soils become drier and microbial activity declines. We compared microclimate, tree performance, and a wide range of proxies for soil nutrient availability in four watersheds along a west-east transect in the Brooks Range during the growing seasons of 2013 and 2014. We hypothesized that soil nutrient availability would track closely with the strong west-east precipitation gradient, with higher rainfall and greater soil nutrient availability in the western Brooks Range. We expected to find that soil water contents in the west are near optimum for nitrogen mineralization, while those in the east are below optimum. Needle nitrogen concentration, net photosynthesis, branch extension growth, and growth in the main stem are expected to decline with the hypothesized decrease in soil nutrient availability. The results of our study will elucidate the current controls on growth of trees near the

Transpirational water loss in invaded and restored semiarid riparian forests

Science.gov (United States)

Georgianne W. Moore; M. Keith Owens

2011-01-01

The invasive tree, Tamarix sp., was introduced to the United States in the 1800s to stabilize stream banks. The riparian ecosystem adjacent to the middle Rio Grande River in central NewMexico consists of mature cottonwood (Populus fremontii ) gallery forests with a dense Tamarix understory. We hypothesized that Populus would compensate for reduced competition by...

Drought reconstruction in eastern Hulun Buir steppe, China and its linkages to the sea surface temperatures in the Pacific Ocean

Science.gov (United States)

Liu, Na; Liu, Yu; Bao, Guang; Bao, Ming; Wang, Yanchao; Zhang, Lizhi; Ge, Yuxiang; Bao, Wurigen; Tian, Heng

2016-01-01

A tree-ring width chronology covering the period 1780-2013 AD was developed from Pinus sylvestris var. mongolica for the eastern Hulun Buir steppe, a region located on the edge of the eastern Mongolian Plateau, China. Climate-growth response analysis revealed drought stress to be the primary limiting factor for tree growth. Therefore, the mean February-July standardized precipitation evapotranspiration index (SPEI) was reconstructed over the period 1819-2013, where the reconstruction could account for 32.8% of the variance in the instrumental record over the calibration period 1953-2011. Comparison with other tree-ring-based moisture sequences from nearby areas confirmed a high degree of confidence in our reconstruction. Severe drought intervals since the late 1970s in our study area consisted with the weakening East Asian summer monsoon, which modulating regional moisture conditions in semi-arid zone over northern China. Drought variations in the study area significantly correlated with sea surface temperatures (SSTs) in North Pacific Ocean, suggesting a possible connection of regional hydroclimatic variations to the Pacific Decadal Oscillation (PDO). The potential influence associated with El Niño-Southern Oscillation (ENSO) was primarily analyzed.

Spatial characteristics of tree diameter distributions in a temperate old-growth forest.

Science.gov (United States)

Zhang, Chunyu; Wei, Yanbo; Zhao, Xiuhai; von Gadow, Klaus

2013-01-01

This contribution identifies spatial characteristics of tree diameter in a temperate forest in north-eastern China, based on a fully censused observational study area covering 500×600 m. Mark correlation analysis with three null hypothesis models was used to determine departure from expectations at different neighborhood distances. Tree positions are clumped at all investigated scales in all 37 studied species, while the diameters of most species are spatially negatively correlated, especially at short distances. Interestingly, all three cases showing short-distance attraction of dbh marks are associated with light-demanding shrub species. The short-distance attraction of dbh marks indicates spatially aggregated cohorts of stems of similar size. The percentage of species showing significant dbh suppression peaked at a 4 m distance under the heterogeneous Poisson model. At scales exceeding the peak distance, the percentage of species showing significant dbh suppression decreases sharply with increasing distances. The evidence from this large observational study shows that some of the variation of the spatial characteristics of tree diameters is related variations of topography and soil chemistry. However, an obvious interpretation of this result is still lacking. Thus, removing competitors surrounding the target trees is an effective way to avoid neighboring competition effects reducing the growth of valuable target trees in forest management practice.

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.

Forest decline research in Eastern Central Europe and Bavaria

International Nuclear Information System (INIS)

Reuther, M.; Kirchner, M.; Kirchinger, E.; Reiter, H.; Roesel, K.; Pfeifer, U.

1991-07-01

In 26 conference contributions, the condition of the forest in eastern central Europe (new Federal German laender, CSFR, Hungary, Romania, Bulgaria, Estonia, Poland) and in Bavaria and Austria is described. The methodics of the countries' comprehensive monitoring and ecosystem analyzes in selected sites with their results are presented, mostly for the 80s. Possibilities and advantages of the modelling of forest ecosystems by computer are indicated as well as the gain of knowledge from extensive screening. For some regions, especially the Sudeten, maps showing the spatial distribution of airborne pollutants are presented. Pollutant concentrations are, in part, related to emittors. In almost all cases, indirect effects of acidic gaseous pollutants via changes in soil chemism are blamed for tree disease jointly with other factors or their outcome (silvicultural mistakes, drought, insect infestation). A striking fact is that in Hungary and Romania, unlike other European countries, oak-trees not conifers are most seriously affected. (UWA) [de

Short-term effects of reduced-impact logging on Copaifera spp. (Fabaceae) regeneration in eastern Amazon

Science.gov (United States)

Carine Klauberg; Edson Vidal; Carlos Alberto Silva; Andrew Thomas Hudak; Manuela Oliveira; Pedro Higuchi

2017-01-01

Timber management directly influences the population dynamics of tree species, like Copaifera spp. (copaíba), which provide oil-resin with ecological and economic importance. The aim of this study was to evaluate the structure and population dynamics of Copaifera in unmanaged and managed stands by reduced-impact logging (RIL) in eastern Amazon in Pará state, Brazil....

AMS radiocarbon investigation of the African baobab: Searching for the oldest tree

Energy Technology Data Exchange (ETDEWEB)

Patrut, Adrian, E-mail: apatrut@gmail.com [Babes-Bolyai University, Department of Chemistry, Arany Janos 11, 400028 Cluj-Napoca (Romania); Reden, Karl F. von [Woods Hole Oceanographic Institution, Department of Geology and Geophysics, NOSAMS Facility, 360 Woods Hole Rd., Mailstop 8, Woods Hole, MA 02543 (United States); Mayne, Diana H. [Baobab Trust, P.O. Box 1566, Parklands 2121, Johannesburg (South Africa); Lowy, Daniel A. [FlexEl, LLC, 387 Technology Drive, College Park, MD 20742 (United States); Patrut, Roxana T. [Babes-Bolyai University, Department of Biology and Geology, Gh. Bilascu 44, 400015 Cluj-Napoca (Romania)

2013-01-15

The Glencoe baobab, a very large specimen from South Africa, split twice in 2009. Several wood samples were collected from the eastern cavity, from the outer part of the main section and also from the largest broken segment which was connected to this section. These wood samples were processed and investigated by AMS radiocarbon dating. The radiocarbon date of the oldest sample was found to be 1838 {+-} 21 BP, which corresponds to a calibrated age of 1835 {+-} 40 years. Thus, the Glencoe baobab becomes the oldest dated baobab and also the oldest angiosperm tree with accurate dating results. The distribution of dating results revealed that the Glencoe baobab is a multi-generation tree, with several standing or collapsed and partially fused stems, showing different ages.

Thermotolerance and Photosystem II Behaviour in Co-occuring Temperate Tree Species Exposed to Short-term Extreme Heat Waves

Science.gov (United States)

Guha, A.; Warren, J.; Cummings, C.; Han, J.

2017-12-01

Thermal stress can induce irreversible photodamage with longer consequences for plant metabolism. We focused on photosystem II (PSII) behaviour to understand how this complex responds in different co-occuring temperate trees exposed to short-term extreme heat waves. The study was designed for understanding complex heat tolerance mechanisms in trees. During manipulative heat-wave experiments, we monitored instantaneous PSII performance and tracked both transient and chronic PSII damages using chlorophyll a fluorescence characteristics. Fluorescence signals were used to simulate PSII bioenergetic processes. The light (Fv'/Fm') and dark-adapted (Fv/Fm) fluorescence traits including fast induction kinetics (OJIP), electron transport rate, PSII operating efficiency and quenching capacities were significantly affected by the heat treatments. Loss in PSII efficiency was more apparent in species like black cottonwood, yellow poplar, walnuts and conifers, whereas oaks maintained relatively better PSII functions. The post-heat recovery of Fv/Fm varied across the studied species showing differential carry over effects. PSII down-regulation was one of dominant factors for the loss in operational photosynthesis during extreme heat wave events. Both light and dark-adapted fluorescence characteristics showed loss in photo-regulatory functions and photodamage. Some resilient species showed rapid recovery from transient PSII damage, whereas fingerprints of chronic PSII damage were observed in susceptibles. Thresholds for Fv/Fm and non-photochemical quenching were identified for the studied species. PSII malfunctioning was largely associated with the observed photosynthetic down-regulation during heat wave treatments, however, its physiological recovery should be a key factor to determine species resilience to short-term extreme heat wave events.

Selection of black poplars for water use efficiency

OpenAIRE

Orlović Saša S.; Pajević Slobodanka P.; Krstić Borivoj Đ.

2002-01-01

Photosynthesis, transpiration, water use efficiency (WUE) and biomass production have been investigated in nine black poplar clones (section Aigeiros) in three field experiments. Eastern cottonwood clones (Populus deltoides) had the highest net photosynthesis and water use efficiency. European black poplar clones had the highest transpiration intensity. Correlation analysis showed that net photosynthesis was in a high positive correlation with biomass. Medium negative correlations existed bet...

Non-linear growth in tree ferns, Dicksonia antarctica and Cyathea australis

OpenAIRE

Blair, David P.; Blanchard, Wade; Banks, Sam C.; Lindenmayer, David B.

2017-01-01

Tree ferns are an important structural component of forests in many countries. However, because their regeneration is often unrelated to major disturbances, their age is often difficult to determine. In addition, rates of growth may not be uniform, which further complicates attempts to determine their age. In this study, we measured 5 years of growth of Cyathea australis and Dicksonia antarctica after a large wildfire in 2009 in south-eastern Australia. We found growth rates of these two spec...

Status of Sassafras albidum (Nutt.) Nees in the presence of laurel wilt disease and throughout the eastern United States

Science.gov (United States)

KaDonna C. Randolph

2017-01-01

Sassafras albidum (Sassafras) is an ecologically important tree species that is widely distributed throughout the eastern United States. Sassafras is presently threatened by Raffaelea lauricola, a fungus vectored by Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae; Redbay Ambrosia Beetle), which...

Internal and external control of net photosynthesis and stomatal conductance of mature eastern white pine (Pinus strobus)

Science.gov (United States)

Chris A. Maier; R.O. Teskey

1992-01-01

Leaf gas exchange and water relations were monitored in the upper canopy of two 25 m tall eastern white pine (Pinus strobus L.) trees over two consecutive growing seasons (1986 and 1987). Examination of the seasonal and diurnal patterns of net photosynthesis and leaf conductance showed that both internal and external (environmental) factors were...

Can dendrochronology procedures estimate historical Tree Water Footprint?

Science.gov (United States)

Fernandes, Tarcísio J. G.; Del Campo, Antonio D.; Molina, Antonio J.

2013-04-01

Whole estimates of tree water use are becoming increasingly important in forest science and forest scientists have long sought to develop reliable techniques to estimate tree water use. In this sense accurately determining or estimate the quantity of water transpired by trees and forests is important and can be used to determine "green" water footprint. The use of dendrochronology is relative common in the study of effects and interactions between growth and climatic variables, but few studies deal with the relationship with water footprint. The main objective of this study is determining the historical tree water-use in a planted stand by dendrochronological approaches. This study was performed in South-eastern Spain, in an area covered by 50-60 years old Pinus halepensis Mil. plantations with high tree density (ca.1288/ha) due to low forest management. The experimental set-up consisted of two plots (30x30m), one corresponding to a thinning treatment performed in 2008 (t10) and the other thinned in 1998 (t1) to assess the mid-term effects of thinning. After one year of thinning four representative trees were select in each plot to measure transpiration by heat pulse sensor (sapflow velocity, vs). The accumulated daily values of transpiration (L day-1) were estimated multiplying the values of vs by sapwood area of each selected tree. After transpiration measurements two cores per tree were taken for establishing the tree-rings chronologies. The cores were prepared, their ring-width were measured and standardised in basal area increment index (BAI-i) following usual dendrochronological methods. The dendrochronology analyses showed a general variability in ring width during the initial growth (15 years), while in the following years the width rings were very small, conditioned by climate. The year after thinning (1999 or 2009) all trees in the treatments showed significant increases in ring width. The average vs for t1 and t10 were 3.59 cm h-1 and 1.95 cm h-1, and

Development and Application of Genomic Resources in an Endangered Palaeoendemic Tree, Parrotia subaequalis (Hamamelidaceae From Eastern China

Directory of Open Access Journals (Sweden)

Yun-Yan Zhang

2018-03-01

Full Text Available Parrotia subaequalis is an endangered palaeoendemic tree from disjunct montane sites in eastern China. Due to the lack of effective genomic resources, the genetic diversity and population structure of this endangered species are not clearly understood. In this study, we conducted paired-end shotgun sequencing (2 × 125 bp of genomic DNA for two individuals of P. subaequalis on the Illumina HiSeq platform. Based on the resulting sequences, we have successfully assembled the complete chloroplast genome of P. subaequalis, as well as identified the polymorphic chloroplast microsatellites (cpSSRs, nuclear microsatellites (nSSRs and mutational hotspots of chloroplast. Ten polymorphic cpSSR loci and 12 polymorphic nSSR loci were used to genotype 96 individuals of P. subaequalis from six populations to estimate genetic diversity and population structure. Our results revealed that P. subaequalis exhibited abundant genetic diversity (e.g., cpSSRs: Hcp = 0.862; nSSRs: HT = 0.559 and high genetic differentiation (e.g., cpSSRs: RST = 0.652; nSSRs: RST = 0.331, and characterized by a low pollen-to-seed migration ratio (r ≈ 1.78. These genetic patterns are attributable to its long evolutionary histories and low levels of contemporary inter-population gene flow by pollen and seed. In addition, lack of isolation-by-distance pattern and strong population genetic structuring in both marker systems, suggests that long-term isolation and/or habitat fragmentation as well as genetic drift may have also contributed to the geographic differentiation of P. subaequalis. Therefore, long-term habitat protection is the most important methods to prevent further loss of genetic variation and a decrease in effective population size. Furthermore, both cpSSRs and nSSRs revealed that P. subaequalis populations consisted of three genetic clusters, which should be considered as separated conservation units.

Tree range expansion in eastern North America fails to keep pace with climate warming at northern range limits.

Science.gov (United States)

Sittaro, Fabian; Paquette, Alain; Messier, Christian; Nock, Charles A

2017-08-01

Rising global temperatures are suggested to be drivers of shifts in tree species ranges. The resulting changes in community composition may negatively impact forest ecosystem function. However, long-term shifts in tree species ranges remain poorly documented. We test for shifts in the northern range limits of 16 temperate tree species in Quebec, Canada, using forest inventory data spanning three decades, 15° of longitude and 7° of latitude. Range shifts were correlated with climate warming and dispersal traits to understand potential mechanisms underlying changes. Shifts were calculated as the change in the 95th percentile of latitudinal occurrence between two inventory periods (1970-1978, 2000-2012) and for two life stages: saplings and adults. We also examined sapling and adult range offsets within each inventory, and changes in the offset through time. Tree species ranges shifted predominantly northward, although species responses varied. As expected shifts were greater for tree saplings, 0.34 km yr -1 , than for adults, 0.13 km yr -1 . Range limits were generally further north for adults compared to saplings, but the difference diminished through time, consistent with patterns observed for range shifts within each life stage. This suggests caution should be exercised when interpreting geographic range offsets between life stages as evidence of range shifts in the absence of temporal data. Species latitudinal velocities were on average climate change and were mostly unrelated to dispersal traits. Finally, our results add to the body of evidence suggesting tree species are mostly limited in their capacity to track climate warming, supporting concerns that warming will negatively impact the functioning of forest ecosystems. © 2017 John Wiley & Sons Ltd.

Basin-Wide Amazon Forest Tree Mortality From a Large 2005 Storm

Science.gov (United States)

Negron Juarez, R. I.; Chambers, J. Q.; Guimaraes, G.; Zeng, H.; Raupp, C.; Marra, D. M.; Ribeiro, G.; Saatchi, S. S.; Higuchi, N.

2010-12-01

Blowdowns are a recurrent characteristic of Amazon forests and are produced, among others, by squall lines. Squall lines are aligned clusters (typical length of 1000 km, width of 200 km) of deep convective cells that produce heavy rainfall during the dry season and significant rainfall during the wet season. These squall lines (accompanied by intense downbursts from convective cells) have been associated with large blowdowns characterized by uprooted, snapped trees, and trees being dragged down by other falling trees. Most squall lines in Amazonia form along the northeastern coast of South America as sea breeze-induced instability lines and propagate inside the continent. They occur frequently (~4 times per month), and can reach the central and even extreme western parts of Amazonia. Squall lines can also be generated inside the Amazon and propagate toward the equator. In January 2005 a squall line propagated from south to north across the entire Amazon basin producing widespread forest tree mortality and contributed to the elevated mortality observed that year. Over the Manaus region (3.4 x104 km2), disturbed forest patches generated by the squall produced a mortality of 0.3-0.5 million trees, equivalent to 30% of the observed annual deforestation reported in 2005 over the same area. The elevated mortality observed in the Central Amazon in 2005 is unlikely to be related to the 2005 Amazon drought since drought did not affect Central or Eastern Amazonia. Assuming a similar rate of forest mortality across the basin, the squall line could have potentially produced tree mortality estimated at 542 ± 121 million trees, equivalent to 23% of the mean annual biomass accumulation estimated for these forests. Our results highlight the vulnerability of Amazon trees to wind-driven mortality associated with convective storms. This vulnerability is likely to increase in a warming climate with models projecting an increase in storm intensity.

Suppression of greasy spot disease caused by Mycosphaerella citri Whiteside on grapefruit trees in an organic orchard using an aqueous organic mixture of composted cornmeal, humic acid, molasses, and fish oil vs vegetable oil

Science.gov (United States)

Greasy spot disease of citrus, caused by the fungus Mycosphaerella citri Whiteside, afflicts citrus trees in all citrus-growing areas of the United States, eastern Mexico, Central America, and the Caribbean islands, causing premature defoliation, blemished fruit, and reduced tree vigor, yield, and f...

Imprint of the Atlantic multidecadal oscillation on tree-ring widths in northeastern Asia since 1568.

Directory of Open Access Journals (Sweden)

Xiaochun Wang

Full Text Available We present a new tree-ring reconstruction of the Atlantic Multidecadal Oscillation (AMO spanning 1568-2007 CE from northeast Asia. Comparison of the instrumental AMO index, an existing tree-ring based AMO reconstruction, and this new record show strongly similar annual to multidecadal patterns of variation over the last 440 years. Warm phases of the AMO are related to increases in growth of Scots pine trees and moisture availability in northeast China and central eastern Siberia. Multi-tape method (MTM and cross-wavelet analyses indicate that robust multidecadal (∼64-128 years variability is present throughout the new proxy record. Our results have important implications concerning the influence of North Atlantic sea surface temperatures on East Asian climate, and provide support for the possibility of an AMO signature on global multidecadal climate variability.

Illinois' Forests 2010

Science.gov (United States)

Susan J. Crocker; Mark D. Nelson; Charles J. Barnett; Brett J. Butler; Grant M. Domke; Mark H. Hansen; Mark A. Hatfield; Tonya W. Lister; Dacia M. Meneguzzo; Ronald J. Piva; Barry T. Wilson; Christopher W. Woodall

2013-01-01

The second full annual inventory of Illinois' forests, completed in 2010, reports more than 4.8 million acres of forest land and 97 tree species. Forest land is dominated by oak/hickory and elm/ash/cottonwood forest-type groups, which occupy 93 percent of total forest land area. The volume of growing stock on timberland totals 7.2 billion cubic feet. The average...

Nebraska's Forests 2010

Science.gov (United States)

Dacia M Meneguzzo; Susan J. Crocker; Mark D. Nelson; Charles J. Barnett; Brett J. Butler; Grant M. Domke; Mark H. Hansen; Mark A. Hatfield; Greg C. Liknes; Andrew J. Lister; Tonya W. Lister; Ronald J. Piva; Barry T. (Ty) Wilson; Christopher W. Woodall

2012-01-01

The second full annual inventory of Nebraska's forests reports more than 1.5 million acres of forest land and 39 tree species. Forest land is dominated by the elm/ash/cottonwood and oak/hickory forest types, which occupy nearly half of the total forest land area. The volume of growing stock on timberland currently totals 1.1 billion cubic feet. The average annual...

Phylogenetic Patterns of Extinction Risk in the Eastern Arc Ecosystems, an African Biodiversity Hotspot

OpenAIRE

Yessoufou, Kowiyou; Daru, Barnabas H.; Davies, T. Jonathan

2012-01-01

There is an urgent need to reduce drastically the rate at which biodiversity is declining worldwide. Phylogenetic methods are increasingly being recognised as providing a useful framework for predicting future losses, and guiding efforts for pre-emptive conservation actions. In this study, we used a reconstructed phylogenetic tree of angiosperm species of the Eastern Arc Mountains - an important African biodiversity hotspot - and described the distribution of extinction risk across taxonomic ...

The Role of Trees on Farms: Challenges and Opportunities

International Nuclear Information System (INIS)

Nyamai, D.O

2007-01-01

The challenges facing Kenyan forestry are deforestation and degradation due to increased demand for wood and additional agricultural land, inadequate resources to strengthen capacities in specific research areas including resource accounting, modelling the beneficial effects of carbon sequestration, policy analysis and products development for market dominance, great variations in institutional development and capacity for trees on farm and agroforestry research and development and inadequate research resources to mention but a few. The opportunities for improved forestry research include, economic growth, social welfare, promoting technologies and innovations for value-added processing agroforestry products for local and external effects, emerging private sector and existing regional market such as Common Market for Eastern and Southern Africa and the East African Community for opportunities for trade in agroforestry products and formulation of policies in favour of privatisation of services and management particularly the privatisation of industrial forest plantations that would offer opportunities for the development of smallholder tree crop enterprise

The role of remnant trees in carbon sequestration, vegetation structure and tree diversity of early succession regrowing fallows in eastern Sierra Leone

DEFF Research Database (Denmark)

Cuni Sanchez, Aida; Lindsell, Jeremy A.

2017-01-01

Remnant tree presence affects forest recovery after slash-and-burn agriculture. However, little is known about its effect on above-ground carbon stocks, especially in Africa. We focused our study on Sierra Leone, part of the Upper Guinean forests, an important centre of endemism threatened...

Community organization of tree species along soil gradients in a north-eastern USA forest

NARCIS (Netherlands)

Bigalow, S.W.; Canham, C.D.

2002-01-01

1 A study was carried out in oak-northern hardwood forest in NW Connecticut USA involving measurements of growth, light and soil environment of saplings of six canopy trees that are strongly associated with particular soil types as adults. The objectives were to determine patterns of growth response

Evidence of recovery of Juniperus virginiana trees from sulfur pollution after the Clean Air Act.

Science.gov (United States)

Thomas, Richard B; Spal, Scott E; Smith, Kenneth R; Nippert, Jesse B

2013-09-17

Using dendroisotopic techniques, we show the recovery of Juniperus virginiana L. (eastern red cedar) trees in the Central Appalachian Mountains from decades of acidic pollution. Acid deposition over much of the 20th century reduced stomatal conductance of leaves, thereby increasing intrinsic water-use efficiency of the Juniperus trees. These data indicate that the stomata of Juniperus may be more sensitive to acid deposition than to increasing atmospheric CO2. A breakpoint in the 100-y δ(13)C tree ring chronology occurred around 1980, as the legacy of sulfur dioxide emissions declined following the enactment of the Clean Air Act in 1970, indicating a gradual increase in stomatal conductance (despite rising levels of atmospheric CO2) and a concurrent increase in photosynthesis related to decreasing acid deposition and increasing atmospheric CO2. Tree ring δ(34)S shows a synchronous change in the sources of sulfur used at the whole-tree level that indicates a reduced anthropogenic influence. The increase in growth and the δ(13)C and δ(34)S trends in the tree ring chronology of these Juniperus trees provide evidence for a distinct physiological response to changes in atmospheric SO2 emissions since ∼1980 and signify the positive impacts of landmark environmental legislation to facilitate recovery of forest ecosystems from acid deposition.

Combining tree-ring metal concentrations and lead, carbon and oxygen isotopes to reconstruct peri-urban atmospheric pollution

Directory of Open Access Journals (Sweden)

Annick Doucet

2012-08-01

Full Text Available In this study, we analysed the tree-ring metal concentrations and isotope ratios of five stands located in three contrasted settings to infer the diffuse air pollution history of the northern part of the Windsor–Québec City Corridor in eastern Canada. Tree-ring series show that the Cd and Zn accumulation rates were higher between 1960 and 1986 and that the long-term acidification of the soil (Ca/Al series was likely induced by NOx and SOx deposition (δ15N and δ13C trends as proxy. The Pb concentrations and 206Pb/207Pb ratios indicate that the dominant source of lead from 1880 to the 1920s was the combustion of north-eastern American coal, which was succeeded by the combustion of leaded gasoline from the 1920s to the end of the 1980s. Our modelling approach allows separating the climatic and anthropogenic effects on the tree-ring δ13C and δ18O responses. Diffuse air pollution caused an enrichment in 13C in all stands and a decrease of the δ18O values only in three of the stands. This study indicates that dendrogeochemistry can show contrasted responses to environmental changes and that the combination of several independent indicators constitutes a powerful tool to reconstruct the air pollution history in the complex context of peri-urban regions.

IMPACT OF AGROFORESTRY PARKLAND SYSTEM ON MAIZE PRODUCTIVITY BY SMALLHOLDER FARMERS IN EASTERN HIGHLANDS OF KENYA

Directory of Open Access Journals (Sweden)

Elton Ndlovu

2016-12-01

Full Text Available A field experiment was carried on farms at Kyeni South in Eastern highlands of Kenya. The purpose of this study was to investigate on the effects of identified common tree species on growth and yield of maize on farms. The selected tree species found to be prevalently growing on farms were Croton macrostachyus Hochst. Ex Delile, Cordia africana Lam. and Grevillea robusta A. Cunn. Growth in basal diameter, height, leaf chlorophyll content and final grain yield was assessed on maize plants selected from the plots under the trees and control plots (away from trees. The maize plants in G. robusta plots had significantly lower mean basal diameter of 1.67 cm at 6 weeks after crop emergence (WACE and 1.96 cm at 9 WACE. No significant differences were observed in plant height in plots under different tree species. Significant suppression of chlorophyll development in maize (indicated by SPAD readings was observed in all the plots under the identified tree species at 6 WACE (P < 0.01. G. robusta plots had significantly lower grain yield of 1.57 t ha-1 compared to the control plots that had the highest mean yield of 2.21 t ha-1. Proper crown management is necessary in agroforestry systems.

Chronic water stress reduces tree growth and the carbon sink of deciduous hardwood forests.

Science.gov (United States)

Brzostek, Edward R; Dragoni, Danilo; Schmid, Hans Peter; Rahman, Abdullah F; Sims, Daniel; Wayson, Craig A; Johnson, Daniel J; Phillips, Richard P

2014-08-01

Predicted decreases in water availability across the temperate forest biome have the potential to offset gains in carbon (C) uptake from phenology trends, rising atmospheric CO2 , and nitrogen deposition. While it is well established that severe droughts reduce the C sink of forests by inducing tree mortality, the impacts of mild but chronic water stress on forest phenology and physiology are largely unknown. We quantified the C consequences of chronic water stress using a 13-year record of tree growth (n = 200 trees), soil moisture, and ecosystem C balance at the Morgan-Monroe State Forest (MMSF) in Indiana, and a regional 11-year record of tree growth (n > 300 000 trees) and water availability for the 20 most dominant deciduous broadleaf tree species across the eastern and midwestern USA. We show that despite ~26 more days of C assimilation by trees at the MMSF, increasing water stress decreased the number of days of wood production by ~42 days over the same period, reducing the annual accrual of C in woody biomass by 41%. Across the deciduous forest region, water stress induced similar declines in tree growth, particularly for water-demanding 'mesophytic' tree species. Given the current replacement of water-stress adapted 'xerophytic' tree species by mesophytic tree species, we estimate that chronic water stress has the potential to decrease the C sink of deciduous forests by up to 17% (0.04 Pg C yr(-1) ) in the coming decades. This reduction in the C sink due to mesophication and chronic water stress is equivalent to an additional 1-3 days of global C emissions from fossil fuel burning each year. Collectively, our results indicate that regional declines in water availability may offset the growth-enhancing effects of other global changes and reduce the extent to which forests ameliorate climate warming. © 2014 John Wiley & Sons Ltd.

Development of a channel classification to evaluate potential for cottonwood restoration, lower segments of the Middle Missouri River, South Dakota and Nebraska

Science.gov (United States)

Jacobson, Robert B.; Elliott, Caroline M.; Huhmann, Brittany L.

2010-01-01

This report documents development of a spatially explicit river and flood-plain classification to evaluate potential for cottonwood restoration along the Sharpe and Fort Randall segments of the Middle Missouri River. This project involved evaluating existing topographic, water-surface elevation, and soils data to determine if they were sufficient to create a classification similar to the Land Capability Potential Index (LCPI) developed by Jacobson and others (U.S. Geological Survey Scientific Investigations Report 2007–5256) and developing a geomorphically based classification to apply to evaluating restoration potential.Existing topographic, water-surface elevation, and soils data for the Middle Missouri River were not sufficient to replicate the LCPI. The 1/3-arc-second National Elevation Dataset delineated most of the topographic complexity and produced cumulative frequency distributions similar to a high-resolution 5-meter topographic dataset developed for the Lower Missouri River. However, lack of bathymetry in the National Elevation Dataset produces a potentially critical bias in evaluation of frequently flooded surfaces close to the river. High-resolution soils data alone were insufficient to replace the information content of the LCPI. In test reaches in the Lower Missouri River, soil drainage classes from the Soil Survey Geographic Database database correctly classified 0.8–98.9 percent of the flood-plain area at or below the 5-year return interval flood stage depending on state of channel incision; on average for river miles 423–811, soil drainage class correctly classified only 30.2 percent of the flood-plain area at or below the 5-year return interval flood stage. Lack of congruence between soil characteristics and present-day hydrology results from relatively rapid incision and aggradation of segments of the Missouri River resulting from impoundments and engineering. The most sparsely available data in the Middle Missouri River were water

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...

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...

The influence of cattle grazing and grass seeding on coniferous regeneration after shelterwood cutting in eastern Oregon.

Science.gov (United States)

K.W. Seidel; J. Michael Geist; Gerald S. Strickler

1990-01-01

Natural regeneration was abundant, regardless of grazing and grass seeding treatments,after shelterwood cutting to three overstory densities (27, 73, and 119 square feet of basal area per acre) in mixed conifer stands in the Starkey Experimental Forest and Range in eastern Oregon. After 6 years, the number of tree seedlings ranged from about 3,800 per acre on the low-...

Invasion of Winter Moth in New England: Effects of Defoliation and Site Quality on Tree Mortality

Directory of Open Access Journals (Sweden)

Michael J. Simmons

2014-10-01

Full Text Available Widespread and prolonged defoliation by the European winter moth, Operophtera brumata L., has occurred in forests of eastern Massachusetts for more than a decade and populations of winter moth continue to invade new areas of New England. This study characterized the forests of eastern Massachusetts invaded by winter moth and related the duration of winter moth defoliation estimated using dendrochronology to observed levels of tree mortality and understory woody plant density. Quercus basal area mortality in mixed Quercus and mixed Quercus—Pinus strobus forests in eastern Massachusetts ranged from 0–30%; mortality of Quercus in these forests was related to site quality and the number of winter moth defoliation events. In addition, winter moth defoliation events lead to a subsequent increase in understory woody plant density. Our results indicate that winter moth defoliation has been an important disturbance in New England forests that may have lasting impacts.

Forest Growth Responses to Drought at Short- and Long-Term Scales in Spain: Squeezing the Stress Memory from Tree Rings

Directory of Open Access Journals (Sweden)

J. Julio Camarero

2018-02-01

Full Text Available Drought-triggered declines in forest productivity and associated die-off events have increased considerably due to climate warming in the last decades. There is an increasing interest in quantifying the resilience capacity of forests against climate warming and drought to uncover how different stands and tree species will resist and recover after more frequent and intense droughts. Trees form annual growth rings that represent an accurate record of how forest growth responded to past droughts. Here we use dendrochronology to quantify the radial growth of different forests subjected to contrasting climatic conditions in Spain during the last half century. Particularly, we considered four climatically contrasting areas where dominant forests showed clear signs of drought-induced dieback. Studied forests included wet sites dominated by silver fir (Abies alba in the Pyrenees and beech (Fagus sylvatica stands in northern Spain, and drought-prone sites dominated by Scots pine (Pinus sylvestris in eastern Spain and black pine (Pinus nigra in the semi-arid south-eastern Spain. We quantified the growth reduction caused by different droughts and assessed the short-and long-term resilience capacity of declining vs. non-declining trees in each forest. In all cases, drought induced a marked growth reduction regardless tree vigor. However, the capacity to recover after drought (resilience at short- and long-term scales varied greatly between declining and non-declining individuals. In the case of beech and silver fir, non-declining individuals presented greater growth rates and capacity to recover after drought than declining individuals. For Scots pine, the resilience to drought was found to be lower in recent years regardless the tree vigor, but the growth reduction caused by successive droughts was more pronounced in declining than in non-declining individuals. In the black pine forest an extreme drought induced a marked growth reduction in declining

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. The resul......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...... as the complementing theory with a number of examples....

Distance-independent individual tree diameter-increment model for Thuya [Tetraclinis articulata (VAHL. MAST.] stands in Tunisia

Directory of Open Access Journals (Sweden)

T. Sghaier

2013-12-01

Full Text Available Aim of study: The aim of the work was to develop an individual tree diameter-increment model for Thuya (Tetraclinis articulata in Tunisia.Area of study: The natural Tetraclinis articulata stands at Jbel Lattrech in north-eastern of Tunisia.Material and methods:  Data came from 200 trees located in 50 sample plots. The diameter at age t and the diameter increment for the last five years obtained from cores taken at breast height were measured for each tree. Four difference equations derived from the base functions of Richards, Lundqvist, Hossfeld IV and Weibull were tested using the age-independent formulations of the growth functions. Both numerical and graphical analyses were used to evaluate the performance of the candidate models.Main results: Based on the analysis, the age-independent difference equation derived from the base function Richards model was selected. Two of the three parameters (growth rate and shape parameter of the retained model were related to site quality, represented by a Growth Index, stand density and the basal area in larger trees divided by diameter of the subject tree expressing the inter-tree competition.Research highlights: The proposed model can be useful for predicting the diameter growth of Tetraclinis articulata in Tunisia when age is not available or for trees growing in uneven-aged stands.Keywords: Age-independent growth model; difference equations; Tetraclinis articulata; Tunisia.

Overcoming Constraints to High-Yield Plantation-Grown Hardwoods in the Southeastern United States

Energy Technology Data Exchange (ETDEWEB)

None

2008-06-26

This project was comprised of the following four inter-related tasks: Task 1 Plantation Maintenance and Measurement--Data on dry weight productivity per tree and/or growth as measured by individual tree height and diameter at a specified height on the stem was determined at the end of each of five years corresponding to ages 2 through 6. Measurements of height and diameter were recorded once a month during the growing season on a subsample of four trees per clone per species per treatment combination. Dry biomass in the leaf litter traps during the growing season once the canopy has closed was periodically collected and measured. Foliar nutrient levels were determined once a month by removing LPI 8 on each subsampled measurement tree and completing nutrient analyses. Weather data, including precipitation, minimum and maximum temperature and photosynthetically active radiation on an hourly basis were recorded daily. Information on irrigation rates and fertilization levels were collected. Task 2 Intra- And Interspecific Variation In Osmotic Potential--The specific objectives of this task were: (1) to determine whether limitation in water availability constrains productivity and influences leaf osmotic potential of cottonwood, sycamore, and/or sweetgum growing under short-rotation field conditions, (2) to document the occurrence of osmotic adjustment under varying levels of water availability levels, and (3) to determine the effect of nitrogen fertilization on osmotic potential and response to irrigation. Task 3 Leaf Gas Exchange And Water-Use Efficiency--The specific objectives of this task were: (1) to quantify the contribution of photosynthesis, respiration, and water-use efficiency to the productivity of individual cottonwood, sycamore, and sweetgum trees grown under various levels of water and/or nutrient availability, and (2) to quantify intra- and interspecific variability for photosynthesis, respiration, and water-use efficiency for cottonwood, sycamore, and

Environmental and Water Quality Operational Studies. Reservoir Shoreline Revegetation Guidelines.

Science.gov (United States)

1986-11-01

24. Taller trees such as green ash, cottonwood (Populus spp.), red maple (Acer rubrum), and persimmon (Diospyros virginiana ) should be planted in...be left aboveground to prevent moisture loss due to wicking. Any excess should be pruned off. Gray and Leiser (1982) provide the following... pruning , staking woody stems, and installing fencing around individual plants or the entire site to provide protection from animals or humans. Additional

Six centuries of May-July precipitation in Cyprus from tree rings

Science.gov (United States)

Touchan, Ramzi; Christou, Andreas K.; Meko, David M.

2014-12-01

A May-July precipitation nested reconstruction for the period AD 1415-2010 was developed from multi-century tree-ring records of Pinus nigra, Pinus brutia, and Cedrus brevifolia for Cyprus. Calibration and verification statistics for the period 1917-2010 show a good level of skill, and split-sample validation over 1917-2010 supports temporal stability of the tree-ring signal for precipitation. Smoothed annual time series of reconstructed precipitation and a tally of drought events in a moving time window indicate that the calibration period is not representative of the full range of drought variability. While convective precipitation in the warm season may be driven strongly by local factors, composite maps of geopotential height anomaly for dry years and wet years support large-scale atmospheric-flow influence related to height anomalies over the broader region of northeast Africa and the eastern Mediterranean. Emerging positive trend in reconstruction residuals may be an early sign of exacerbation of drought stress on trees by recent warming in May-July. Future warming expected from increases in greenhouse gases poses a threat to forest resources in Cyprus and elsewhere in the Mediterranean.

Surface tree languages and parallel derivation trees

NARCIS (Netherlands)

Engelfriet, Joost

1976-01-01

The surface tree languages obtained by top-down finite state transformation of monadic trees are exactly the frontier-preserving homomorphic images of sets of derivation trees of ETOL systems. The corresponding class of tree transformation languages is therefore equal to the class of ETOL languages.

TreePics: visualizing trees with pictures

Directory of Open Access Journals (Sweden)

Nicolas Puillandre

2017-09-01

Full Text Available While many programs are available to edit phylogenetic trees, associating pictures with branch tips in an efficient and automatic way is not an available option. Here, we present TreePics, a standalone software that uses a web browser to visualize phylogenetic trees in Newick format and that associates pictures (typically, pictures of the voucher specimens to the tip of each branch. Pictures are visualized as thumbnails and can be enlarged by a mouse rollover. Further, several pictures can be selected and displayed in a separate window for visual comparison. TreePics works either online or in a full standalone version, where it can display trees with several thousands of pictures (depending on the memory available. We argue that TreePics can be particularly useful in a preliminary stage of research, such as to quickly detect conflicts between a DNA-based phylogenetic tree and morphological variation, that may be due to contamination that needs to be removed prior to final analyses, or the presence of species complexes.

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 ".

GENETIC ENGINEERING TO ENHANCE MERCURY PHYTOREMEDIATION

OpenAIRE

Ruiz, Oscar N.; Daniell, Henry

2009-01-01

Most phytoremediation studies utilize merA or merB genes to modify plants via the nuclear or chloroplast genome, expressing organomercurial lyase and/or mercuric ion reductase in the cytoplasm, endoplasmic reticulum or within plastids. Several plant species including Arabidopsis, tobacco, poplar, rice, Eastern cottonwood, peanut, salt marsh grass and Chlorella have been transformed with these genes. Transgenic plants grew exceedingly well in soil contaminated with organic (~400 μM PMA) or ino...

Buffalo Metropolitan Area, New York Water Resources Management. Interim Report on Feasibility of Flood Management in Cazenovia Creek Watershed.

Science.gov (United States)

1977-03-01

Ulmus rubra slippery elm Ulmus thomasii rock elm Pinus strobus white pine Juglans cinerea. butternut Juglans nigra black walnut Carya ovata shagbark...West Seneca X : X : X Town of Elm : X X X Town of Aurora : X : Town of Boston X : Town of Colden : X : 5.i, Table 1 (cont’d) Flood Insurance Status for...grandidentata bigtooth aspen Populus deltoides eastern cottonwood Rhus typhina staghorn. sumc Betula alleghaniesis yellow birch Ulmus americana. American elm

Practical breeding of cottonwood in the north-central region

Science.gov (United States)

Carl A. Mohn

1973-01-01

More than 20 years ago Scott Pauley (1949) designated the genus Populus as the "guinea pig of forest-tree breeding. This designation is still appropriate as evidenced by the steady, almost overwhelming, stream of publications related to the genetics and breeding of poplars. A good indication of the scope and depth of genetic work with poplars...

Tracking population loss in Cornus florida since discovery of Discula destructiva, causal agent of dogwood anthracnose, in eastern North America

Science.gov (United States)

William E. Jones; William D. Smith; Daniel B. Twardus

2012-01-01

The purpose of this evaluation monitoring project was to document the losses of flowering dogwood, Cornus florida (L.), an important ornamental and wildlife tree that grows across much of Eastern North America. The project was prompted in 2001 by the apparent abundance of flowering dogwoods along roadsides in the Morgantown, WV, area, despite a...

Determination of self shielding factors and gamma attenuation effects for tree ring samples

International Nuclear Information System (INIS)

Dagistan Sahin; Kenan Uenlue

2012-01-01

Determination of tree ring chemistry using Neutron Activation Analysis (NAA) is part of an ongoing research between Penn State University (PSU) and Cornell University, The Malcolm and Carolyn Wiener Laboratory for Aegean and Near Eastern Dendrochronology. Tree-ring chemistry yields valuable data for environmental event signatures. These signatures are a complex function of elemental concentration. To be certain about concentration of signature elements, it is necessary to perform the measurements and corrections with the lowest error and maximum accuracy possible. Accurate and precise values of energy dependent neutron flux at dry irradiation tubes and detector efficiency for tree ring sample are calculated for Penn State Breazeale Reactor (PSBR). For the calculation of energy dependent and self shielding corrected neutron flux, detailed model of the TRIGA Mark III reactor at PSU with updated fuel compositions was prepared using the MCNP utility for reactor evolution (MURE) libraries. Dry irradiation tube, sample holder and sample were also included in the model. The thermal flux self-shielding correction factors due to the sample holder and sample for were calculated and verified with previously published values. The Geant-4 model of the gamma spectroscopy system, developed at Radiation Science and Engineering Center (RSEC), was improved and absolute detector efficiency for tree-ring samples was calculated. (author)

Large-scale carbon stock assessment of woody vegetation in tropical dry deciduous forest of Sathanur reserve forest, Eastern Ghats, India.

Science.gov (United States)

Gandhi, Durai Sanjay; Sundarapandian, Somaiah

2017-04-01

Tropical dry forests are one of the most widely distributed ecosystems in tropics, which remain neglected in research, especially in the Eastern Ghats. Therefore, the present study was aimed to quantify the carbon storage in woody vegetation (trees and lianas) on large scale (30, 1 ha plots) in the dry deciduous forest of Sathanur reserve forest of Eastern Ghats. Biomass of adult (≥10 cm DBH) trees was estimated by species-specific allometric equations using diameter and wood density of species whereas in juvenile tree population and lianas, their respective general allometric equations were used to estimate the biomass. The fractional value 0.4453 was used to convert dry biomass into carbon in woody vegetation of tropical dry forest. The mean aboveground biomass value of juvenile tree population was 1.86 Mg/ha. The aboveground biomass of adult trees ranged from 64.81 to 624.96 Mg/ha with a mean of 245.90 Mg/ha. The mean aboveground biomass value of lianas was 7.98 Mg/ha. The total biomass of woody vegetation (adult trees + juvenile population of trees + lianas) ranged from 85.02 to 723.46 Mg/ha, with a mean value of 295.04 Mg/ha. Total carbon accumulated in woody vegetation in tropical dry deciduous forest ranged from 37.86 to 322.16 Mg/ha with a mean value of 131.38 Mg/ha. Adult trees accumulated 94.81% of woody biomass carbon followed by lianas (3.99%) and juvenile population of trees (1.20%). Albizia amara has the greatest biomass and carbon stock (58.31%) among trees except for two plots (24 and 25) where Chloroxylon swietenia contributed more to biomass and carbon stock. Similarly, Albizia amara (52.4%) showed greater carbon storage in juvenile population of trees followed by Chloroxylon swietenia (21.9%). Pterolobium hexapetalum (38.86%) showed a greater accumulation of carbon in liana species followed by Combretum albidum (33.04%). Even though, all the study plots are located within 10 km radius, they show a significant spatial variation among

Climate, trees, pests, and weeds: Change, uncertainty, and biotic stressors in eastern US national park forests

Science.gov (United States)

Nicholas A. Fisichelli; Scott R. Abella; Matthew Peters; Frank J. Krist

2014-01-01

The US National Park Service (NPS) manages over 8900 km2 of forest area in the eastern United States where climate change and nonnative species are altering forest structure, composition, and processes. Understanding potential forest change in response to climate, differences in habitat projections among models (uncertainty), and nonnative biotic...

ColorTree: a batch customization tool for phylogenic trees.

Science.gov (United States)

Chen, Wei-Hua; Lercher, Martin J

2009-07-31

Genome sequencing projects and comparative genomics studies typically aim to trace the evolutionary history of large gene sets, often requiring human inspection of hundreds of phylogenetic trees. If trees are checked for compatibility with an explicit null hypothesis (e.g., the monophyly of certain groups), this daunting task is greatly facilitated by an appropriate coloring scheme. In this note, we introduce ColorTree, a simple yet powerful batch customization tool for phylogenic trees. Based on pattern matching rules, ColorTree applies a set of customizations to an input tree file, e.g., coloring labels or branches. The customized trees are saved to an output file, which can then be viewed and further edited by Dendroscope (a freely available tree viewer). ColorTree runs on any Perl installation as a stand-alone command line tool, and its application can thus be easily automated. This way, hundreds of phylogenic trees can be customized for easy visual inspection in a matter of minutes. ColorTree allows efficient and flexible visual customization of large tree sets through the application of a user-supplied configuration file to multiple tree files.

Middle Eastern rhinoplasty.

Science.gov (United States)

Azizzadeh, Babak; Mashkevich, Grigoriy

2010-02-01

The ethnic appearance of the Middle Eastern nose is defined by several unique visual features, particularly a high radix, wide overprojecting dorsum, and an amorphous hanging nasal tip. These external characteristics reflect distinct structural properties of the osseo-cartilaginous nasal framework and skin-soft tissue envelope in patients of Middle Eastern extraction. The goal, and the ultimate challenge, of rhinoplasty on Middle Eastern patients is to achieve balanced aesthetic refinement, while avoiding surgical westernization. Detailed understanding of the ethnic visual harmony in a Middle Eastern nose greatly assists in preserving native nasal-facial relationships during rhinoplasty on Middle Eastern patients. Esthetic alteration of a Middle Eastern nose follows a different set of goals and principles compared with rhinoplasties on white or other ethnic patients. This article highlights the inherent nasal features of the Middle Eastern nose and reviews pertinent concepts of rhinoplasty on Middle Eastern patients. Essential considerations in the process spanning the consultation and surgery are reviewed. Reliable operative techniques that achieve a successful aesthetic outcome are discussed in detail. Copyright 2010 Elsevier Inc. All rights reserved.

Statistically-Estimated Tree Composition for the Northeastern United States at Euro-American Settlement.

Directory of Open Access Journals (Sweden)

Christopher J Paciorek

Full Text Available We present a gridded 8 km-resolution data product of the estimated composition of tree taxa at the time of Euro-American settlement of the northeastern United States and the statistical methodology used to produce the product from trees recorded by land surveyors. Composition is defined as the proportion of stems larger than approximately 20 cm diameter at breast height for 22 tree taxa, generally at the genus level. The data come from settlement-era public survey records that are transcribed and then aggregated spatially, giving count data. The domain is divided into two regions, eastern (Maine to Ohio and midwestern (Indiana to Minnesota. Public Land Survey point data in the midwestern region (ca. 0.8-km resolution are aggregated to a regular 8 km grid, while data in the eastern region, from Town Proprietor Surveys, are aggregated at the township level in irregularly-shaped local administrative units. The product is based on a Bayesian statistical model fit to the count data that estimates composition on the 8 km grid across the entire domain. The statistical model is designed to handle data from both the regular grid and the irregularly-shaped townships and allows us to estimate composition at locations with no data and to smooth over noise caused by limited counts in locations with data. Critically, the model also allows us to quantify uncertainty in our composition estimates, making the product suitable for applications employing data assimilation. We expect this data product to be useful for understanding the state of vegetation in the northeastern United States prior to large-scale Euro-American settlement. In addition to specific regional questions, the data product can also serve as a baseline against which to investigate how forests and ecosystems change after intensive settlement. The data product is being made available at the NIS data portal as version 1.0.

Vegetation Evaluation and Recommendations: Dredge Material Placement Areas and Adjacent Lands, Kaskaskia River Navigation Project, New Athens to Fayetteville.

Science.gov (United States)

1981-06-03

cottonwood), Salix interior (sandbar willow), Salix nigra (black willow), and Ulmus rubra * ( slippery elm ) . Somewhat drier sites with a predominance of fine...Dutch Elm Disease. *Ulmus rubra Muhl. SLIPPERY ELM . Common tree in floodplain woods; also occasional in DMP. *Valerianella radiata (L.) Dufr. CORN... elm ), Carya tomentosa (mocker- nut hickory), and Quercus bicolor (swamp white oak). Shrubs and woody vines play a major role in the ecology of these

Tree Colors: Color Schemes for Tree-Structured Data.

Science.gov (United States)

Tennekes, Martijn; de Jonge, Edwin

2014-12-01

We present a method to map tree structures to colors from the Hue-Chroma-Luminance color model, which is known for its well balanced perceptual properties. The Tree Colors method can be tuned with several parameters, whose effect on the resulting color schemes is discussed in detail. We provide a free and open source implementation with sensible parameter defaults. Categorical data are very common in statistical graphics, and often these categories form a classification tree. We evaluate applying Tree Colors to tree structured data with a survey on a large group of users from a national statistical institute. Our user study suggests that Tree Colors are useful, not only for improving node-link diagrams, but also for unveiling tree structure in non-hierarchical visualizations.

How do riparian woody seedlings survive seasonal drought?

Science.gov (United States)

Stella, John C; Battles, John J

2010-11-01

In semi-arid regions, a major population limitation for riparian trees is seedling desiccation during the dry season that follows annual spring floods. We investigated the stress response of first-year pioneer riparian seedlings to experimental water table declines (0, 1 and 3 cm day(-1)), focusing on the three dominant cottonwood and willows (family Salicaceae) in California's San Joaquin Basin. We analyzed growth and belowground allocation response to water stress, and used logistic regression to determine if these traits had an influence on individual survival. The models indicate that high root growth (>3 mm day(-1)) and low shoot:root ratios (water-use efficiency for surviving water stress. Both S. gooddingii and sandbar willow (S. exigua) reduced leaf size from controls, whereas Fremont cottonwood (Populus fremontii) sustained a 29% reduction in specific leaf area (from 13.4 to 9.6 m(2) kg(-1)). The functional responses exhibited by Goodding's willow, the more drought-tolerant species, may play a role in its greater relative abundance in dry regions such as the San Joaquin Basin. This study highlights the potential for a shift in riparian forest composition. Under a future drier climate regime or under reduced regulated river flows, our results suggest that willow establishment will be favored over cottonwood.

Synergistic effects of drought and deforestation on the resilience of the south-eastern Amazon rainforest

OpenAIRE

Staal, A.; Dekkers, S.; Hirota Magalhaes, M.; Nes, van, E.H.

2015-01-01

The south-eastern Amazon rainforest is subject to ongoing deforestation and is expected to become drier due to climate change. Recent analyses of the distribution of tree cover in the tropics show three modes that have been interpreted as representing alternative stable states: forest, savanna and treeless states. This situation implies that a change in environmental conditions, such as in the climate, could cause critical transitions from a forest towards a savanna ecosystem. Shifts to savan...

TreePOD: Sensitivity-Aware Selection of Pareto-Optimal Decision Trees.

Science.gov (United States)

Muhlbacher, Thomas; Linhardt, Lorenz; Moller, Torsten; Piringer, Harald

2018-01-01

Balancing accuracy gains with other objectives such as interpretability is a key challenge when building decision trees. However, this process is difficult to automate because it involves know-how about the domain as well as the purpose of the model. This paper presents TreePOD, a new approach for sensitivity-aware model selection along trade-offs. TreePOD is based on exploring a large set of candidate trees generated by sampling the parameters of tree construction algorithms. Based on this set, visualizations of quantitative and qualitative tree aspects provide a comprehensive overview of possible tree characteristics. Along trade-offs between two objectives, TreePOD provides efficient selection guidance by focusing on Pareto-optimal tree candidates. TreePOD also conveys the sensitivities of tree characteristics on variations of selected parameters by extending the tree generation process with a full-factorial sampling. We demonstrate how TreePOD supports a variety of tasks involved in decision tree selection and describe its integration in a holistic workflow for building and selecting decision trees. For evaluation, we illustrate a case study for predicting critical power grid states, and we report qualitative feedback from domain experts in the energy sector. This feedback suggests that TreePOD enables users with and without statistical background a confident and efficient identification of suitable decision trees.

Using Landsat TM and NFI data to estimate wood volume, tree biomass and stand age in Dalarna

Energy Technology Data Exchange (ETDEWEB)

Reese, Heather; Nilsson, Mats

1999-10-01

As part of the `Monitoring of forest ecosystems` project, within the MISTRA program Remote Sensing for the Environment (RESE), and also with funding from the County Administration Board of Dalarna, a demonstration project was undertaken to estimate forest stand parameters in Dalarna with the use of satellite data. Using two full scenes of Landsat Thematic Mapper data and sample plot data from the Swedish National Forest Inventory, estimations of above ground tree biomass, age, total wood volume, and separate tree species volumes were made using the `k Nearest Neighbor` method. Accuracy assessment results at the single pixel level for total wood volume are consistent with results from previous kNN estimations, with an overall relative RMSE of 75% for the western scene, and 58% overall relative RMSE for the eastern scene. Validation data show a bias of the estimate toward the mean value of the estimation data. The pixel level estimates of above ground tree biomass and age had similar validation results to those for total wood volume. Biomass estimates had a 77% relative RMSE for the western scene, and 69% for the eastern scene. Age estimates had a relative RMSE of 60% in the western scene and 57% in the eastern scene. The results may suggest the need to incorporate a geographic limitation on the plots used in the estimation, and to further investigate the co-registration between the satellite and plot data. While pixel lever errors are high, an aggregation of the estimates to larger (compartment-sized) areas could decrease the error significantly. Previous similar studies have shown that an RMSE of 10% for total wood volume can be obtained for as small areas as 100 to 450 hectares. The estimates from this study will be evaluated for use by the County Administration Board of Dalarna to find areas of ecological interest and to assist in planning 14 refs, 4 figs, 4 tabs

Two Trees: Migrating Fault Trees to Decision Trees for Real Time Fault Detection on International Space Station

Science.gov (United States)

Lee, Charles; Alena, Richard L.; Robinson, Peter

2004-01-01

We started from ISS fault trees example to migrate to decision trees, presented a method to convert fault trees to decision trees. The method shows that the visualizations of root cause of fault are easier and the tree manipulating becomes more programmatic via available decision tree programs. The visualization of decision trees for the diagnostic shows a format of straight forward and easy understands. For ISS real time fault diagnostic, the status of the systems could be shown by mining the signals through the trees and see where it stops at. The other advantage to use decision trees is that the trees can learn the fault patterns and predict the future fault from the historic data. The learning is not only on the static data sets but also can be online, through accumulating the real time data sets, the decision trees can gain and store faults patterns in the trees and recognize them when they come.

Higher fine-scale genetic structure in peripheral than in core populations of a long-lived and mixed-mating conifer--eastern white cedar (Thuja occidentalis L.).

Science.gov (United States)

Pandey, Madhav; Rajora, Om P

2012-04-05

Fine-scale or spatial genetic structure (SGS) is one of the key genetic characteristics of plant populations. Several evolutionary and ecological processes and population characteristics influence the level of SGS within plant populations. Higher fine-scale genetic structure may be expected in peripheral than core populations of long-lived forest trees, owing to the differences in the magnitude of operating evolutionary and ecological forces such as gene flow, genetic drift, effective population size and founder effects. We addressed this question using eastern white cedar (Thuja occidentalis) as a model species for declining to endangered long-lived tree species with mixed-mating system. We determined the SGS in two core and two peripheral populations of eastern white cedar from its Maritime Canadian eastern range using six nuclear microsatellite DNA markers. Significant SGS ranging from 15 m to 75 m distance classes was observed in the four studied populations. An analysis of combined four populations revealed significant positive SGS up to the 45 m distance class. The mean positive significant SGS observed in the peripheral populations was up to six times (up to 90 m) of that observed in the core populations (15 m). Spatial autocorrelation coefficients and correlograms of single and sub-sets of populations were statistically significant. The extent of within-population SGS was significantly negatively correlated with all genetic diversity parameters. Significant heterogeneity of within-population SGS was observed for 0-15 m and 61-90 m between core and peripheral populations. Average Sp, and gene flow distances were higher in peripheral (Sp = 0.023, σg = 135 m) than in core (Sp = 0.014, σg = 109 m) populations. However, the mean neighborhood size was higher in the core (Nb = 82) than in the peripheral (Nb = 48) populations. Eastern white cedar populations have significant fine-scale genetic structure at short distances. Peripheral populations have several

Pricing and reimbursement frameworks in Central Eastern Europe: a decision tool to support choices.

Science.gov (United States)

Kolasa, Katarzyna; Kalo, Zoltan; Hornby, Edward

2015-02-01

Given limited financial resources in the Central Eastern European (CEE) region, challenges in obtaining access to innovative medical technologies are formidable. The objective of this research was to develop a decision tree that supports decision makers and drug manufacturers from CEE region in their search for optimal innovative pricing and reimbursement scheme (IPRSs). A systematic literature review was performed to search for published IPRSs, and then ten experts from the CEE region were interviewed to ascertain their opinions on these schemes. In total, 33 articles representing 46 unique IPRSs were analyzed. Based on our literature review and subsequent expert input, key decision nodes and branches of the decision tree were developed. The results indicate that outcome-based schemes are better suited to deal with uncertainties surrounding cost effectiveness, while non-outcome-based schemes are more appropriate for pricing and budget impact challenges.

Evolutionary melting pots: a biodiversity hotspot shaped by ring diversifications around the Black Sea in the Eastern tree frog (Hyla orientalis).

Science.gov (United States)

Dufresnes, Christophe; Litvinchuk, Spartak N; Leuenberger, Julien; Ghali, Karim; Zinenko, Oleksandr; Stöck, Matthias; Perrin, Nicolas

2016-09-01

Hotspots of intraspecific genetic diversity, which are of primary importance for the conservation of species, have been associated with glacial refugia, that is areas where species survived the Quaternary climatic oscillations. However, the proximate mechanisms generating these hotspots remain an open issue. Hotspots may reflect the long-term persistence of large refugial populations; alternatively, they may result from allopatric differentiation between small and isolated populations, that later admixed. Here, we test these two scenarios in a widely distributed species of tree frog, Hyla orientalis, which inhabits Asia Minor and southeastern Europe. We apply a fine-scale phylogeographic survey, combining fast-evolving mitochondrial and nuclear markers, with a dense sampling throughout the range, as well as ecological niche modelling, to understand what shaped the genetic variation of this species. We documented an important diversity centre around the Black Sea, composed of multiple allopatric and/or parapatric diversifications, likely driven by a combination of Pleistocene climatic fluctuations and complex regional topography. Remarkably, this diversification forms a ring around the Black Sea, from the Caucasus through Anatolia and eastern Europe, with terminal forms coming into contact and partially admixing in Crimea. Our results support the view that glacial refugia generate rather than host genetic diversity and can also function as evolutionary melting pots of biodiversity. Moreover, we report a new case of ring diversification, triggered by a large, yet cohesive dispersal barrier, a very rare situation in nature. Finally, we emphasize the Black Sea region as an important centre of intraspecific diversity in the Palearctic with implications for conservation. © 2016 John Wiley & Sons Ltd.

Eastern hemlock response to even- and uneven-age management in the Acadian forest: results from the Penobscot Experimental Forest long-term silviculture study

Science.gov (United States)

John C. Brissette; Laura S. Kenefic

2000-01-01

Eastern hemlock (Tsuga canadensis (L.) Carr.) is an important tree species in the mixed-species conifer forests of northern New England and adjacent Canada. Hemlock is very tolerant of understory conditions; consequently, it responds differently to various silvicultural treatments. In a long-term study at the Penobscot Experimental Forest in east-...

Potential for tree rings to reveal spatial patterns of past drought variability across western Australia

Science.gov (United States)

O'Donnell, Alison J.; Cook, Edward R.; Palmer, Jonathan G.; Turney, Chris S. M.; Grierson, Pauline F.

2018-02-01

Proxy records have provided major insights into the variability of past climates over long timescales. However, for much of the Southern Hemisphere, the ability to identify spatial patterns of past climatic variability is constrained by the sparse distribution of proxy records. This is particularly true for mainland Australia, where relatively few proxy records are located. Here, we (1) assess the potential to use existing proxy records in the Australasian region—starting with the only two multi-century tree-ring proxies from mainland Australia—to reveal spatial patterns of past hydroclimatic variability across the western third of the continent, and (2) identify strategic locations to target for the development of new proxy records. We show that the two existing tree-ring records allow robust reconstructions of past hydroclimatic variability over spatially broad areas (i.e. > 3° × 3°) in inland north- and south-western Australia. Our results reveal synchronous periods of drought and wet conditions between the inland northern and southern regions of western Australia as well as a generally anti-phase relationship with hydroclimate in eastern Australia over the last two centuries. The inclusion of 174 tree-ring proxy records from Tasmania, New Zealand and Indonesia and a coral record from Queensland did not improve the reconstruction potential over western Australia. However, our findings suggest that the addition of relatively few new proxy records from key locations in western Australia that currently have low reconstruction skill will enable the development of a comprehensive drought atlas for the region, and provide a critical link to the drought atlases of monsoonal Asia and eastern Australia and New Zealand.

Limited growth recovery after drought-induced forest dieback in very defoliated trees of two pine species

Directory of Open Access Journals (Sweden)

Guillermo eGuada

2016-04-01

Full Text Available Mediterranean pine forests display high resilience after extreme climatic events such as severe droughts. However, recent dry spells causing growth decline and triggering forest dieback challenge the capacity of some forests to recover following major disturbances. To describe how resilient the responses of forests to drought can be, we quantified growth dynamics in plantations of two pine species (Scots pine, black pine located in south-eastern Spain and showing drought-triggered dieback. Radial growth was characterized at inter- (tree-ring width and intra-annual (xylogenesis scales in three defoliation levels. It was assumed that the higher defoliation the more negative the impact of drought on tree growth. Tree-ring width chronologies were built and xylogenesis was characterized three years after the last severe drought occurred. Annual growth data and the number of tracheids produced in different stages of xylem formation were related to climate data at several time scales. Drought negatively impacted growth of the most defoliated trees in both pine species. In Scots pine, xylem formation started earlier in the non-defoliated than in the most defoliated trees. Defoliated trees presented the shortest duration of the radial-enlargement phase in both species. On average the most defoliated trees formed 60% of the number of mature tracheids formed by the non-defoliated trees in both species. Since radial enlargement is the xylogenesis phase most tightly related to final growth, this explains why the most defoliated trees grew the least due to their altered xylogenesis phases. Our findings indicate a very limited resilience capacity of drought-defoliated Scots and black pines. Moreover, droughts produce legacy effects on xylogenesis of highly defoliated trees which could not recover previous growth rates and are thus more prone to die.

Short-Term Effects of Reduced-Impact Logging on Copaifera spp. (Fabaceae Regeneration in Eastern Amazon

Directory of Open Access Journals (Sweden)

Carine Klauberg

2017-07-01

Full Text Available Timber management directly influences the population dynamics of tree species, like Copaifera spp. (copaíba, which provide oil-resin with ecological and economic importance. The aim of this study was to evaluate the structure and population dynamics of Copaifera in unmanaged and managed stands by reduced-impact logging (RIL in eastern Amazon in Pará state, Brazil. Based on a stem map of the study area, 40 Copaifera trees were randomly selected, where an equal number of trees were selected in managed and unmanaged stands. A transect of 10 × 100 m was centered at each tree (50 m each side to assess Copaifera regeneration. Transects were subdivided into ten plots, of which six were systematically chosen to assess the height, diameter and number of Copaifera seedlings and saplings. The field assessment occurred in 2011 and 2013. To estimate the amount of sunlight transmitted to the forest floor, we computed canopy cover from airborne LiDAR data. According to the results, the abundance of Copaifera seedlings/saplings was higher in managed than unmanaged stands. About 5% of Copaifera regeneration was found between 45–50 m from the Copaifera tree while ~73% of regeneration was concentrated within a 10 m radius of the Copaifera tree. We verified that the diameter distribution of Copaifera regeneration was not a negative exponential distribution, as is typical of most tree species in natural forest. Rather, the Copaifera regeneration had a spatially aggregated distribution. In this short-term analysis, the impact of timber management is not negatively affecting the population structure or dynamics of Copaifera regeneration.

Tree Nut Allergies

Science.gov (United States)

... Blog Vision Awards Common Allergens Tree Nut Allergy Tree Nut Allergy Learn about tree nut allergy, how ... a Tree Nut Label card . Allergic Reactions to Tree Nuts Tree nuts can cause a severe and ...

Mobile carbohydrates in Himalayan treeline trees I. Evidence for carbon gain limitation but not for growth limitation.

Science.gov (United States)

Li, Mai-He; Xiao, Wen-Fa; Wang, San-Gen; Cheng, Gen-Wei; Cherubini, Paolo; Cai, Xaio-Hu; Liu, Xing-Liang; Wang, Xiao-Dan; Zhu, Wan-Ze

2008-08-01

To test whether the altitudinal distribution of trees is determined by a carbon shortage or an insufficient sugar fraction (sugar:starch ratio) in treeline trees, we studied the status of nonstructural carbohydrates (NSC) and their components (total soluble sugars and starch) in Abies fabri (Mast.) Craib and Picea balfouriana var. hirtella Rehd. et Wils. trees along three elevational gradients, ranging from lower elevations to the alpine treeline, on the eastern edge of the Tibetan Plateau. For comparison, we investigated a low-altitude species (Tsuga yunnanensis (Franch.) Pritz.) which served as a warm-climate reference because it is distributed in closed montane forests below 3100 m a.s.l. in the study area. The carbon status of T. yunnanensis responded to altitude differently from that of the treeline species. At the species level, total NSC was not consistently more abundant in treeline trees than in trees of the same species growing at lower elevations. Thus there was no consistent evidence for carbon limitation of growth in treeline trees. For the three treeline species studied (P. balfouriana and A. fabri in the Kang-Ding Valley and A. fabri in the Mo-Xi Valley), winter NSC concentrations in treeline trees were significantly lower than in lower-elevation trees of the same species, suggesting that, in winter, carbon is limited in treeline trees. However, in no case was there total overwinter depletion of NSC or its components in treeline trees. Treeline and low-altitude species had similar sugar:starch ratios of about three at their upper-elevational limits in April. We conclude that survival and growth of trees at the elevational or latitudinal climate limit depend not only on NSC concentration in perennial tissues, but also on the maintenance of an overwintering sugar:starch ratio greater than three.

Conservation implications of deforestation across an elevational gradient in the Eastern Arc Mountains, Tanzania

DEFF Research Database (Denmark)

Hall, Jaclyn; Burgess, Neil David; Lovett, Jon

2009-01-01

Deforestation is a major threat to the conservation of biodiversity, especially within global centers of endemism for plants and animals. Elevation, the major environmental gradient in mountain regions of the world, produces a rapid turnover of species, where some species may exist only in narrow...... elevations and target conservation and restoration efforts throughout these ecosystems' entire elevational ranges.......Deforestation is a major threat to the conservation of biodiversity, especially within global centers of endemism for plants and animals. Elevation, the major environmental gradient in mountain regions of the world, produces a rapid turnover of species, where some species may exist only in narrow...... elevational ranges. We use newly compiled datasets to assess the conservation impact of deforestation on threatened trees across an elevational gradient within the Eastern Arc Mountains of Tanzania. The Eastern Arc has suffered an estimated 80% total loss in historical forest area and has lost 25% of forest...

Big trees, old trees, and growth factor tables

Science.gov (United States)

Kevin T. Smith

2018-01-01

The potential for a tree to reach a great size and to live a long life frequently captures the public's imagination. Sometimes the desire to know the age of an impressively large tree is simple curiosity. For others, the date-of-tree establishment can make a big diff erence for management, particularly for trees at historic sites or those mentioned in property...

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 r on n nodes and suffix links of its internal nodes, we ask the question “Is r a suffix tree?”, i.e., is there a string S whose suffix tree has the same topological structure as r? We place no restrictions on S, in part...

Bioenergy and carbon sequestration potential from energy tree plantation in rural wasteland of North-Eastern India

NARCIS (Netherlands)

Hiloidhari, Moonmoon; Medhi, Hemantajeet; Das, Karabee; Thakur, Indu Shekhar; Baruah, Debendra Chandra

2016-01-01

In this study, carbon sequestration potential via energy tree plantation in the rural wasteland of Assam, India was estimated under two different plantation species scenarios,viz., (i) Acacia nilotica, and (ii) Bambusa tulda. Furthermore, CO2 emission reduction potential in local tea industries by

The chromium in timberline forests in the eastern Tibetan Plateau.

Science.gov (United States)

Luo, Ji; Tang, Ronggui; She, Jia; Chen, Youchao; Gong, Yiwen; Zhou, Jun; Yu, Dong

2013-10-01

In order to study the regional distribution, trait and possible source of chromium in the eastern Tibetan Plateau, we collected samples of xylem, bark, leaves and twigs in two parallel northwest-southeast belt transects (TA and TB) from the Hengduan Mountains. According to the Cr mean concentration, organ/tissue was split into two groups: the high-level organ/tissue (twigs: 1.476 mg kg(-1)) and the low-level organ/tissue (bark: 0.413 mg kg(-1), leaves: 0.340 mg kg(-1) and xylem: 0.194 mg kg(-1)). The mean Cr concentrations of twigs and leaves in TB samples were higher than those in the TA samples, and the mean Cr concentration in both sites gradually reduced from southeast to northwest. Both the southeasterly and southwesterly monsoons could be significant, influential factors in this connection. The top three mean Cr concentrations were S7, S1 and S8, which were closer to the developed city. Mean Cr concentrations in S3, S4 and S5, (remote, high mountains) were relatively low. The high mountains acting as a barrier to the monsoon and the distance from the big city may play important roles in the distribution of Chromium. Furthermore, the relationship between the mean Cr concentration and precipitation, timberline trees as bio-monitors of chromium pollution in polluted areas and the possible source of Cr in the eastern Tibetan Plateau are also discussed. This study may provide reliable proof of Cr contamination processes, and so help in future to prevent further Cr pollution, and also be helpful in understanding the important function of forest ecosystems in relation to atmospheric pollution and global change. To better understand the characteristics of temporal and spatial distribution of Cr concentration, we found that tree ring, fine roots and soil samples are good choices.

Drought timing and local climate determine the sensitivity of eastern temperate forests to drought.

Science.gov (United States)

D'Orangeville, Loïc; Maxwell, Justin; Kneeshaw, Daniel; Pederson, Neil; Duchesne, Louis; Logan, Travis; Houle, Daniel; Arseneault, Dominique; Beier, Colin M; Bishop, Daniel A; Druckenbrod, Daniel; Fraver, Shawn; Girard, François; Halman, Joshua; Hansen, Chris; Hart, Justin L; Hartmann, Henrik; Kaye, Margot; Leblanc, David; Manzoni, Stefano; Ouimet, Rock; Rayback, Shelly; Rollinson, Christine R; Phillips, Richard P

2018-02-20

Projected changes in temperature and drought regime are likely to reduce carbon (C) storage in forests, thereby amplifying rates of climate change. While such reductions are often presumed to be greatest in semi-arid forests that experience widespread tree mortality, the consequences of drought may also be important in temperate mesic forests of Eastern North America (ENA) if tree growth is significantly curtailed by drought. Investigations of the environmental conditions that determine drought sensitivity are critically needed to accurately predict ecosystem feedbacks to climate change. We matched site factors with the growth responses to drought of 10,753 trees across mesic forests of ENA, representing 24 species and 346 stands, to determine the broad-scale drivers of drought sensitivity for the dominant trees in ENA. Here we show that two factors-the timing of drought, and the atmospheric demand for water (i.e., local potential evapotranspiration; PET)-are stronger drivers of drought sensitivity than soil and stand characteristics. Drought-induced reductions in tree growth were greatest when the droughts occurred during early-season peaks in radial growth, especially for trees growing in the warmest, driest regions (i.e., highest PET). Further, mean species trait values (rooting depth and ψ 50 ) were poor predictors of drought sensitivity, as intraspecific variation in sensitivity was equal to or greater than interspecific variation in 17 of 24 species. From a general circulation model ensemble, we find that future increases in early-season PET may exacerbate these effects, and potentially offset gains in C uptake and storage in ENA owing to other global change factors. © 2018 John Wiley & Sons Ltd.

Lichen biogeochemical and spatial dynamics in canopies of Eastern white pine (Pinus strobus)

Science.gov (United States)

Laughlin, M. M.; Martin, J.; Olson, E.

2017-12-01

Forest canopies have been shown to contain complex ecosystem level processes but much of this work is from the tropics or the charismatic tall trees of Oceana and the Pacific Northwestern US. However, many of the processes can occur in other species of trees that are not as tall, as old, nor as surrounded by biological diversity. Such an occurrence is within the lichen diversity and coverage of Eastern white pines (Pinus strobus) in the Lake States region of the US. We used arborist techniques to scale, survey, and document the lichen abundance in three large and regionally old trees (diameter at breast height 70-80+cm, 30m in height, and 100 to 115 years old). These trees represent the first generation of second growth forests to reclaim the landscape following the massive cutover period in the region from 1880s to the 1910s. We surveyed the stem in framed quadrats in the four cardinal directions at every 2 meters, as well as various branch locations, and used digital photographs and image analysis software to quantify coverage. Lichen coverage ranged from 0% to over 50% and increased with height indicating: (1) possible light limitations or bark suitability limitations near the ground, and (2) that conditions, not time, may be more important for lichen abundance. Lastly, because lichens can fix atmospheric nitrogen and absorb substantial amounts of water, we scaled the coverage of lichen to determine the total nitrogen pool and water holding capacity in the footprint of these large trees. The vertical structure of these large trees helps add to these biogeochemical pools and may be an important consideration for management and restoration efforts aimed at slowing nutrient and water loss from upland forests.

Cultural Resources Survey and Testing Along Ditch 19 and Extensive Testing of 23DU289, Dunklin and Stoddard Counties, Missouri.

Science.gov (United States)

1988-06-30

Carya illinoensis ) 1 1 Persimmon (Diospyros virginiana) T 2 2 Pl.um (Prunus sp.) T Red Haw (Crataegus sp.) T 1 11 Red Mulberry (Morus rubra) T...2 Cherry (Prunus sp.) T Cottonwood (Populus sp.) 1 3 Dogwood (Cornus sp.) 1 Hackberry (Celtus occidentalis) 12 9 Hickory, ( Carya sp.) 5 4 Shellhark... Carya laciniosa) T Hornbeam (Ostrya virginiana) 2 Kentucky Coffee Tree( Gymnoeladus dioica)T Locust, T Black (Robinia pseudo-acacia) T Honey

Tradition and Culture Change in the Oklahoma Delaware Big House Community: 1867-1924.

Science.gov (United States)

1981-01-01

sore throat Slippery Elm Ulmus fulva xkwikpi Drink from soaked strips of bark used to relieve chills Wild Black Cherry Prunus scrotina mwmfeli Boiled...Berries used to make dye for baskets Pokeberry Phytolacca americana cAk%.ngwtm Tonic given to chickens made from roots Slippery Elm Ulmus fulva xkwilpi...along drainages, forests of elm , ash, and cottonwood trees. The grasslands extended up the rockier col- luvial slopes where they gave way in places to

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

TreeNetViz: revealing patterns of networks over tree structures.

Science.gov (United States)

Gou, Liang; Zhang, Xiaolong Luke

2011-12-01

Network data often contain important attributes from various dimensions such as social affiliations and areas of expertise in a social network. If such attributes exhibit a tree structure, visualizing a compound graph consisting of tree and network structures becomes complicated. How to visually reveal patterns of a network over a tree has not been fully studied. In this paper, we propose a compound graph model, TreeNet, to support visualization and analysis of a network at multiple levels of aggregation over a tree. We also present a visualization design, TreeNetViz, to offer the multiscale and cross-scale exploration and interaction of a TreeNet graph. TreeNetViz uses a Radial, Space-Filling (RSF) visualization to represent the tree structure, a circle layout with novel optimization to show aggregated networks derived from TreeNet, and an edge bundling technique to reduce visual complexity. Our circular layout algorithm reduces both total edge-crossings and edge length and also considers hierarchical structure constraints and edge weight in a TreeNet graph. These experiments illustrate that the algorithm can reduce visual cluttering in TreeNet graphs. Our case study also shows that TreeNetViz has the potential to support the analysis of a compound graph by revealing multiscale and cross-scale network patterns. © 2011 IEEE

Nesting ecology of Greater Sandhill Cranes (Grus canadensis tabida) in riparian and palustrine wetlands of eastern Idaho

Science.gov (United States)

McWethy, D.B.; Austin, J.E.

2009-01-01

Little information exists on breeding Greater Sandhill Cranes (Grus canadensis tabida) in riparian wetlands of the Intermountain West. We examined the nesting ecology of Sandhill Cranes associated with riparian and palustrine wetlands in the Henry's Fork Watershed in eastern Idaho in 2003. We located 36 active crane nests, 19 in riparian wetlands and 17 in palustrine wetlands. Nesting sites were dominated by rushes (Juncus spp.), sedges (Carex spp.), Broad-leaved Cattail (Typha latifolia) and willow (Salix spp.), and adjacent foraging areas were primarily composed of sagebrush (Artemisia spp.), cinquefoil (Potentilla spp.),Rabbitbrush (Ericameria bloomeri) bunch grasses, upland forbs, Quaking Aspen (Populus tremuloides) and cottonwood (Populus spp.). Mean water depth surrounding nests was 23 cm (SD = 22). A majority of nests (61%) were surrounded by vegetation between 3060 cm, 23% by vegetation 60 cm in height. We were able to determine the fate of 29 nests, of which 20 were successful (69%). Daily nest survival was 0.986 (95% LCI 0.963, UCI 0.995), equivalent to a Mayfield nest success of 0.654 (95% LCI 0.324, UCI 0.853). Model selection favored models with the covariates vegetation type, vegetation height, and water depth. Nest survival increased with increasing water depth surrounding nest sites. Mean water depth was higher around successful nests (30 cm, SD = 21) than unsuccessful nests (15 cm, SD 22). Further research is needed to evaluate the relative contribution of cranes nesting in palustrine and riparian wetlands distributed widely across the Intermountain West.

Sediment Supply as a Control on Plant-Morphodynamic Interactions

Science.gov (United States)

Manners, R.; Wilcox, A. C.; Kui, L.; Stella, J. C.; Lightbody, A.; Sklar, L. S.

2014-12-01

The caliber and quantity of sediment delivered to a channel influences its size and shape, yet we know little about how the sediment supply affects rivers whose geomorphic form is influenced by riparian vegetation. We present results from flume experiments that test the impact of sediment supply on plant-morphodynamic interactions. We introduced two sediment supply conditions to a 28-meter long, sand bedded flume (60 cm wide and 71 cm deep) at the UC-Berkeley Richmond Field Station: equilibrium (balance between sediment transport and supply) and deficit (transport exceeds sediment supply). We conducted ten runs with different riparian seedling configurations (individual plants or patches) and species (tamarisk or cottonwood), and stem and leaf density (0.003-0.47 cm2/cm2), under both sediment supply conditions. Plant species, size, and configuration were important in predicting the topographic adjustments that occurred during our experiments. These influences may be attributed to differences in plant morphology; tamarisk is shrubby while cottonwood is more tree-like, with a single stem and leaves concentrated higher on the plant. The plant-morphodynamic relationship, however, differed for the two sediment supply conditions. During sediment equilibrium, only patches of cottonwood served as sediment sinks compared to an unvegetated bed, but tamarisk patches had no impact on the sediment mass balance. During sediment deficit, in contrast, tamarisk patches accumulated more sediment than unvegetated beds. Stem and leaf density also controlled changes in bed elevation. During equilibrium conditions, increasing the density of cottonwood stems and leaves resulted in greater bed degradation. Conversely, aggradation occurred with increases in the density of tamarisk. For sediment deficit conditions, the relationship between stem and leaf density and the rate of bed change was negative for both species (i.e., higher density resulted in faster rate of scour). The shifting

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.

Visualizing Individual Tree Differences in Tree-Ring Studies

Directory of Open Access Journals (Sweden)

Mario Trouillier

2018-04-01

Full Text Available Averaging tree-ring measurements from multiple individuals is one of the most common procedures in dendrochronology. It serves to filter out noise from individual differences between trees, such as competition, height, and micro-site effects, which ideally results in a site chronology sensitive to regional scale factors such as climate. However, the climate sensitivity of individual trees can be modulated by factors like competition, height, and nitrogen deposition, calling attention to whether average chronologies adequately assess climatic growth-control. In this study, we demonstrate four simple but effective methods to visually assess differences between individual trees. Using individual tree climate-correlations we: (1 employed jitter plots with superimposed metadata to assess potential causes for these differences; (2 plotted the frequency distributions of climate correlations over time as heat maps; (3 mapped the spatial distribution of climate sensitivity over time to assess spatio-temporal dynamics; and (4 used t-distributed Stochastic Neighborhood Embedding (t-SNE to assess which trees were generally more similar in terms of their tree-ring pattern and their correlation with climate variables. This suite of exploratory methods can indicate if individuals in tree-ring datasets respond differently to climate variability, and therefore, should not solely be explored with climate correlations of the mean population chronology.

Fault tree handbook

International Nuclear Information System (INIS)

Haasl, D.F.; Roberts, N.H.; Vesely, W.E.; Goldberg, F.F.

1981-01-01

This handbook describes a methodology for reliability analysis of complex systems such as those which comprise the engineered safety features of nuclear power generating stations. After an initial overview of the available system analysis approaches, the handbook focuses on a description of the deductive method known as fault tree analysis. The following aspects of fault tree analysis are covered: basic concepts for fault tree analysis; basic elements of a fault tree; fault tree construction; probability, statistics, and Boolean algebra for the fault tree analyst; qualitative and quantitative fault tree evaluation techniques; and computer codes for fault tree evaluation. Also discussed are several example problems illustrating the basic concepts of fault tree construction and evaluation

Eco-monitoring of highly contaminated areas: historic heavy metal contamination in tree ring records

Science.gov (United States)

Baross, Norbert; Jordán, Győző; Albert, Julianna; Abdaal, Ahmed; Anton, Attila

2014-05-01

This study examines and compares tree rings of trees grown in a mining area highly contaminated with heavy metals. Tree rings offers an excellent opportunity for eco-monitoring polluted areas. Contamination dispersion from the source to the receptors can be studied in time and space. The sampled area is located in the eastern part of the Matra Mts. of the Inner-Carpathian calc-alkaline Volcanic Arc (Hungary) with abundant historical ore (Pb, Zn, Cu, etc.) mining in the area. Dense forests are composed of the most typical association of the Turkey oak (Quercus cerris). Scots pine (Pinus sylvestris), European black pine (Pinus nigra), oak (Quercus robur), beech (Fagus sylvatica), and hornbeam (Carpinus betulus) also occurs in the landscape. Sampled trees are located within a 1km radius of the abandoned historic ore mines. Sample sites were located above the old mines and waste rock heaps, under the waste rock heaps and on the floodplain of the Ilona Creek. The sampled trees were selected by the following criteria: the tree should be healthy, showing no signs of thunderbolt or diseases and having a minimum diameter of 50 cm. Samples were taken with a tree borer at the height of 150 cm. At the same time, soil samples were also taken near the trees in a 25 cm depth. Prior to laboratory analysis, the samples measured and air dried. Every fifth years tree ring was taken from the samples under microscope, working backwards from the most recent outer ring (2012, the year of the sampling). Samples were digested with a mixture of H2SO4 and H2O2m in Teflon vessels in a microwave unit. The samples were analyzed by ICP-OES instrument. The results were evaluated with statistical method. Results revealed a consistent picture showing distinct locations and years of the contamination history in the former mining area. Some elements are built into the trees more efficiently than other elements depending on mobility in the soil solution that is influenced by soil chemical properties

An Analysis of Overstory Tree Canopy Cover in Sites Occupied by Native and Introduced Cottontails in the Northeastern United States with Recommendations for Habitat Management for New England Cottontail.

Directory of Open Access Journals (Sweden)

Bill Buffum

Full Text Available The New England cottontail (Sylvilagus transitionalis is a high conservation priority in the Northeastern United States and has been listed as a candidate species under the Endangered Species Act. Loss of early successional habitat is the most common explanation for the decline of the species, which is considered to require habitat with dense low vegetation and limited overstory tree canopy. Federal and state wildlife agencies actively encourage landowners to create this habitat type by clearcutting blocks of forest. However, there are recent indications that the species also occupies sites with moderate overstory tree canopy cover. This is important because many landowners have negative views about clearcutting and are more willing to adopt silvicultural approaches that retain some overstory trees. Furthermore, it is possible that clearcuts with no overstory canopy cover may attract the eastern cottontail (S. floridanus, an introduced species with an expanding range. The objective of our study was to provide guidance for future efforts to create habitat that would be more favorable for New England cottontail than eastern cottontail in areas where the two species are sympatric. We analyzed canopy cover at 336 cottontail locations in five states using maximum entropy modelling and other statistical methods. We found that New England cottontail occupied sites with a mean overstory tree canopy cover of 58% (SE±1.36, and was less likely than eastern cottontail to occupy sites with lower overstory canopy cover and more likely to occupy sites with higher overstory canopy cover. Our findings suggest that silvicultural approaches that retain some overstory canopy cover may be appropriate for creating habitat for New England cottontail. We believe that our results will help inform critical management decisions for the conservation of New England cottontail, and that our methodology can be applied to analyses of habitat use of other critical wildlife

Spatial epidemiology of eastern equine encephalitis in Florida.

Science.gov (United States)

Vander Kelen, Patrick T; Downs, Joni A; Stark, Lillian M; Loraamm, Rebecca W; Anderson, James H; Unnasch, Thomas R

2012-11-05

Eastern Equine Encephalitis virus (EEEV) is an alphavirus with high pathogenicity in both humans and horses. Florida continues to have the highest occurrence of human cases in the USA, with four fatalities recorded in 2010. Unlike other states, Florida supports year-round EEEV transmission. This research uses GIS to examine spatial patterns of documented horse cases during 2005-2010 in order to understand the relationships between habitat and transmission intensity of EEEV in Florida. Cumulative incidence rates of EEE in horses were calculated for each county. Two cluster analyses were performed using density-based spatial clustering of applications with noise (DBSCAN). The first analysis was based on regional clustering while the second focused on local clustering. Ecological associations of EEEV were examined using compositional analysis and Euclidean distance analysis to determine if the proportion or proximity of certain habitats played a role in transmission. The DBSCAN algorithm identified five distinct regional spatial clusters that contained 360 of the 438 horse cases. The local clustering resulted in 18 separate clusters containing 105 of the 438 cases. Both the compositional analysis and Euclidean distance analysis indicated that the top five habitats positively associated with horse cases were rural residential areas, crop and pastureland, upland hardwood forests, vegetated non-forested wetlands, and tree plantations. This study demonstrates that in Florida tree plantations are a focus for epizootic transmission of EEEV. It appears both the abundance and proximity of tree plantations are factors associated with increased risk of EEE in horses and therefore humans. This association helps to explain why there is are spatially distinct differences in the amount of EEE horse cases across Florida.

Non-linear growth in tree ferns, Dicksonia antarctica and Cyathea australis.

Science.gov (United States)

Blair, David P; Blanchard, Wade; Banks, Sam C; Lindenmayer, David B

2017-01-01

Tree ferns are an important structural component of forests in many countries. However, because their regeneration is often unrelated to major disturbances, their age is often difficult to determine. In addition, rates of growth may not be uniform, which further complicates attempts to determine their age. In this study, we measured 5 years of growth of Cyathea australis and Dicksonia antarctica after a large wildfire in 2009 in south-eastern Australia. We found growth rates of these two species were unaffected by aspect and elevation but slope had a minor effect with D. antarctica growing 0.3mm faster for each additional degree of slope. Geographic location influenced growth in both species by up to 12 - 14mm/yr. The most consistent factor influencing growth rate, however, was initial height at the time of the 2009 fire; a finding consistent in both species and all geographic locations. For both tree fern species, individuals that were taller at the commencement of the study had greater overall growth for the duration of the study. This effect did not decrease even among the tallest tree ferns in our study (up to 6 metres tall). Overall, Cyathea australis averaged 73 (± 22)mm/year of growth (± 1SD), with the rate increasing 5mm/yr per metre of additional height. Dicksonia antarctica averaged 33 (± 13)mm/year, increasing by 6mm/yr/m. Growth rates dependent on initial height were unexpected and we discuss possible reasons for this finding. Variable growth rates also suggest that common age estimation methods of dividing height by average growth rate are likely to underestimate the age of short tree ferns, while overestimating the age of tall tree ferns, particularly if they have been subject to a fire.

Non-linear growth in tree ferns, Dicksonia antarctica and Cyathea australis.

Directory of Open Access Journals (Sweden)

David P Blair

Full Text Available Tree ferns are an important structural component of forests in many countries. However, because their regeneration is often unrelated to major disturbances, their age is often difficult to determine. In addition, rates of growth may not be uniform, which further complicates attempts to determine their age. In this study, we measured 5 years of growth of Cyathea australis and Dicksonia antarctica after a large wildfire in 2009 in south-eastern Australia. We found growth rates of these two species were unaffected by aspect and elevation but slope had a minor effect with D. antarctica growing 0.3mm faster for each additional degree of slope. Geographic location influenced growth in both species by up to 12 - 14mm/yr. The most consistent factor influencing growth rate, however, was initial height at the time of the 2009 fire; a finding consistent in both species and all geographic locations. For both tree fern species, individuals that were taller at the commencement of the study had greater overall growth for the duration of the study. This effect did not decrease even among the tallest tree ferns in our study (up to 6 metres tall. Overall, Cyathea australis averaged 73 (± 22mm/year of growth (± 1SD, with the rate increasing 5mm/yr per metre of additional height. Dicksonia antarctica averaged 33 (± 13mm/year, increasing by 6mm/yr/m. Growth rates dependent on initial height were unexpected and we discuss possible reasons for this finding. Variable growth rates also suggest that common age estimation methods of dividing height by average growth rate are likely to underestimate the age of short tree ferns, while overestimating the age of tall tree ferns, particularly if they have been subject to a fire.

Growth and mortality patterns in a thinning canopy of post-hurricane regenerating rain forest in eastern Nicaragua (1990-2005

Directory of Open Access Journals (Sweden)

Javier Ruiz

2010-12-01

Full Text Available One of the strongest hypothesis about the maintenance of tree species diversity in tropical areas is disturbance. In order to assess this, the effect of intensive natural disturbances on forest growth and mortality in a thinning canopy was studied after the landfall of hurricane Joan in 1988. We evaluated the growth and mortality rates of the 26 most common tree species of that forest in eastern Nicaragua. Permanent plots were established at two study sites within the damaged area. Growth and mortality rates of all individual trees ≥3.18cm diameter at breast height were assessed annually from 1990 to 2005. During this period the forest underwent two phases: the building phase (marked by increased number of individuals of tree species present after the hurricane and the canopy thinning phase (marked by increased competition and mortality. Our results from the thinning phase show that tree survival was independent of species identity and was positively related to the increase in growth rates. The analysis of mortality presented here aims to test the null hypothesis that individual trees die independently of their species identity. These findings were influenced by the mortality observed during the late thinning phase (2003-2005 and provide evidence in favor of a non-niche hypothesis at the thinning phase of forest regeneration. Rev. Biol. Trop. 58 (4: 1283-1297. Epub 2010 December 01.

Water regime of mechanical-biological pretreated waste materials under fast-growing trees.

Science.gov (United States)

Rüth, Björn; Lennartz, Bernd; Kahle, Petra

2007-10-01

In this study mechanical-biological pre-treated waste material (MBP) was tested for suitability to serve as an alternative surface layer in combination with fast-growing and water-consumptive trees for final covers at landfill sites. The aim was to quantify evapotranspiration and seepage losses by numerical model simulations for two sites in Germany. In addition, the leaf area index (LAI) of six tree species over the growing season as the driving parameter for transpiration calculations was determined experimentally. The maximum LAI varied between 3.8 and 6.1 m2 m(-2) for poplar and willow clones, respectively. The evapotranspiration calculations revealed that the use of MBP waste material for re-cultivation enhanced evapotranspiration by 40 mm year(-1) (10%) over an 11 year calculation period compared to a standard mineral soil. Between 82% (for LAI(max) = 3.8) and 87% (for LAI(max) = 6.1) of the average annual precipitation (506 mm) could be retained from the surface layer assuming eastern German climate conditions, compared with a retention efficiency between 79 and 82% for a mineral soil. Although a MBP layer in conjunction with water-consumptive trees can reduce vertical water losses as compared to mineral substrates, the effect is not sufficient to meet legal regulations.

Integrating tree-ring and wine data from the Palatinate (Germany)

Science.gov (United States)

Konter, Oliver

2017-04-01

Tree-ring growth of conifer trees originating from central European low mountain ranges often reveal indistinct growth-climate relationships. Temperature variations can play a crucial role, whereas water availability can also control the annual growth and become the main dominating factor. The low mountain range Pfälzerwald in the Palatinate region represents the largest contiguous forested area in Germany and features at its most eastern limitation a unique ecological setting due to its sandy soils and reduced water availability. In addition, its north-south orientation and associated lee-effects due to predominating westerlies together with altitudinal differences of more than 300 m lead to higher temperatures, lower precipitation amounts, and, as a forest management consequence, to a proportion of up to 80 % of pine trees. Despite these exceptional ecological and climatological prerequisites, calibrating tree-ring width data from 487 Pinus sylvestris core samples against regional meteorological stations (1950-2011) and gridded data (1901-2011) confirm alternating climate control mechanisms. Comparison with drought-related indices (scPDSI), combining precipitation and temperature, unfolds highest correlations with May-July conditions (r=0.34, psugar content, acidity, alcohol content, and sugar-free extracts in Riesling, Pinot Gris, Pinot Blanc, and Silvaner wines, originating from 15 wineries adjoining the forested area into the plain. Correlation of Riesling must sugar content against regional April-August temperature data reveals a highly significant signal (r=0.73, pSugar-free extract variations of Pinot Gris are significantly controlled by March-September precipitation (r=0.76, psugar content and sugar-free extract data from Riesling and Pinot Gris wine can further elucidate our understanding of longer-term climate variability in the Palatinate region.

Thinning trials in lowland plantations in the Veneto Region (North-eastern Italy

Directory of Open Access Journals (Sweden)

Mario Pividori

2014-06-01

Full Text Available Thinning trials in lowland plantations in the Veneto Region (North-eastern Italy. More than 234 hectares of new plantations of lowland mixed forest have been realized in the last 20 years in the Veneto Region (North-eastern Italy. In many of these is now needed to start thinning operations, but there is a lack of experience about this topic. Aim of this work was to undertake an experimentation on different types of thinnings. The thinning trial has been performed at Bosco San Marco forest, municipality of Cessalto (Venice, in a very dense hornbeam-oak plantation aged 16. In 2010, three different thinning types were implemented on 9 hectares according to the following layout: geometrical (34% of woody mass removed, selective (15%, mixed geometrical-selective (30%, control plot. Three years later no significant differences between thinning trials in term of diametric growth, geometrical thinning excepted, were observed. These results provide a suite of solutions to the forest manager for choosing the early thinning type in high tree density condition.

Tree Regeneration Under Different Land-Use Mosaics in the Brazilian Amazon's "Arc of Deforestation".

Science.gov (United States)

Do Vale, Igor; Miranda, Izildinha Souza; Mitja, Danielle; Grimaldi, Michel; Nelson, Bruce Walker; Desjardins, Thierry; Costa, Luiz Gonzaga Silva

2015-08-01

We studied the tree-regeneration patterns in three distinct agricultural settlements in the Eastern Amazon to test the influence of land-use mosaics. The following questions are addressed: are the floristic structure and composition of regenerating trees affected by the various land-use types applied in the agricultural settlements? Do tree-regeneration patterns respond similarly to distinct land-use mosaics? Is there a relationship between tree regeneration and soil characteristics among the land-use types? The regeneration was inventoried at 45 sampling points in each settlement. At each sampling point, fourteen soil variables were analyzed. Nine different land-use types were considered. The floristic structure and composition of the settlements showed differences in the density of individuals and species and high species heterogeneity among the land-use types. The maximum Jaccard similarity coefficient found between land-use types was only 29%. Shade-tolerant species were the most diverse functional group in most land-use types, including pasture and annual crops, ranging from 91% of the number of species in the conserved and exploited forests of Travessão 338-S to 53% in the invaded pastures of Maçaranduba. The land-use types influenced significantly the floristic structure and composition of regenerating trees in two agricultural settlements, but not in third the settlement, which had greater forest cover. This finding demonstrates that the composition of each land-use mosaic, established by different management approaches, affects regeneration patterns. Tree regeneration was related to soil characteristics in all mosaics. Preparation of the area by burning was most likely the determining factor in the differences in soil characteristics between forests and agricultural areas.

Climatic Signals in Tree Rings of Heritiera fomes Buch.-Ham. in the Sundarbans, Bangladesh.

Science.gov (United States)

Chowdhury, Md Qumruzzaman; De Ridder, Maaike; Beeckman, Hans

2016-01-01

Mangroves occur along the coastlines throughout the tropics and sub-tropics, supporting a wide variety of resources and services. In order to understand the responses of future climate change on this ecosystem, we need to know how mangrove species have responded to climate changes in the recent past. This study aims at exploring the climatic influences on the radial growth of Heritiera fomes from a local to global scale. A total of 40 stem discs were collected at breast height position from two different zones with contrasting salinity in the Sundarbans, Bangladesh. All specimens showed distinct tree rings and most of the trees (70%) could be visually and statistically crossdated. Successful crossdating enabled the development of two zone-specific chronologies. The mean radial increment was significantly higher at low salinity (eastern) zone compared to higher salinity (western) zone. The two zone-specific chronologies synchronized significantly, allowing for the construction of a regional chronology. The annual and monsoon precipitation mainly influence the tree growth of H. fomes. The growth response to local precipitation is similar in both zones except June and November in the western zone, while the significant influence is lacking. The large-scale climatic drivers such as sea surface temperature (SST) of equatorial Pacific and Indian Ocean as well as the El Niño-Southern Oscillation (ENSO) revealed no teleconnection with tree growth. The tree rings of this species are thus an indicator for monsoon precipitation variations in Bangladesh. The wider distribution of this species from the South to South East Asian coast presents an outstanding opportunity for developing a large-scale tree-ring network of mangroves.

Climatic Signals in Tree Rings of Heritiera fomes Buch.-Ham. in the Sundarbans, Bangladesh.

Directory of Open Access Journals (Sweden)

Md Qumruzzaman Chowdhury

Full Text Available Mangroves occur along the coastlines throughout the tropics and sub-tropics, supporting a wide variety of resources and services. In order to understand the responses of future climate change on this ecosystem, we need to know how mangrove species have responded to climate changes in the recent past. This study aims at exploring the climatic influences on the radial growth of Heritiera fomes from a local to global scale. A total of 40 stem discs were collected at breast height position from two different zones with contrasting salinity in the Sundarbans, Bangladesh. All specimens showed distinct tree rings and most of the trees (70% could be visually and statistically crossdated. Successful crossdating enabled the development of two zone-specific chronologies. The mean radial increment was significantly higher at low salinity (eastern zone compared to higher salinity (western zone. The two zone-specific chronologies synchronized significantly, allowing for the construction of a regional chronology. The annual and monsoon precipitation mainly influence the tree growth of H. fomes. The growth response to local precipitation is similar in both zones except June and November in the western zone, while the significant influence is lacking. The large-scale climatic drivers such as sea surface temperature (SST of equatorial Pacific and Indian Ocean as well as the El Niño-Southern Oscillation (ENSO revealed no teleconnection with tree growth. The tree rings of this species are thus an indicator for monsoon precipitation variations in Bangladesh. The wider distribution of this species from the South to South East Asian coast presents an outstanding opportunity for developing a large-scale tree-ring network of mangroves.

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...

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.

Higher fine-scale genetic structure in peripheral than in core populations of a long-lived and mixed-mating conifer - eastern white cedar (Thuja occidentalis L.)

Science.gov (United States)

2012-01-01

Background Fine-scale or spatial genetic structure (SGS) is one of the key genetic characteristics of plant populations. Several evolutionary and ecological processes and population characteristics influence the level of SGS within plant populations. Higher fine-scale genetic structure may be expected in peripheral than core populations of long-lived forest trees, owing to the differences in the magnitude of operating evolutionary and ecological forces such as gene flow, genetic drift, effective population size and founder effects. We addressed this question using eastern white cedar (Thuja occidentalis) as a model species for declining to endangered long-lived tree species with mixed-mating system. Results We determined the SGS in two core and two peripheral populations of eastern white cedar from its Maritime Canadian eastern range using six nuclear microsatellite DNA markers. Significant SGS ranging from 15 m to 75 m distance classes was observed in the four studied populations. An analysis of combined four populations revealed significant positive SGS up to the 45 m distance class. The mean positive significant SGS observed in the peripheral populations was up to six times (up to 90 m) of that observed in the core populations (15 m). Spatial autocorrelation coefficients and correlograms of single and sub-sets of populations were statistically significant. The extent of within-population SGS was significantly negatively correlated with all genetic diversity parameters. Significant heterogeneity of within-population SGS was observed for 0-15 m and 61-90 m between core and peripheral populations. Average Sp, and gene flow distances were higher in peripheral (Sp = 0.023, σg = 135 m) than in core (Sp = 0.014, σg = 109 m) populations. However, the mean neighborhood size was higher in the core (Nb = 82) than in the peripheral (Nb = 48) populations. Conclusion Eastern white cedar populations have significant fine-scale genetic structure at short distances. Peripheral

Higher fine-scale genetic structure in peripheral than in core populations of a long-lived and mixed-mating conifer - eastern white cedar (Thuja occidentalis L.

Directory of Open Access Journals (Sweden)

Pandey Madhav

2012-04-01

Full Text Available Abstract Background Fine-scale or spatial genetic structure (SGS is one of the key genetic characteristics of plant populations. Several evolutionary and ecological processes and population characteristics influence the level of SGS within plant populations. Higher fine-scale genetic structure may be expected in peripheral than core populations of long-lived forest trees, owing to the differences in the magnitude of operating evolutionary and ecological forces such as gene flow, genetic drift, effective population size and founder effects. We addressed this question using eastern white cedar (Thuja occidentalis as a model species for declining to endangered long-lived tree species with mixed-mating system. Results We determined the SGS in two core and two peripheral populations of eastern white cedar from its Maritime Canadian eastern range using six nuclear microsatellite DNA markers. Significant SGS ranging from 15 m to 75 m distance classes was observed in the four studied populations. An analysis of combined four populations revealed significant positive SGS up to the 45 m distance class. The mean positive significant SGS observed in the peripheral populations was up to six times (up to 90 m of that observed in the core populations (15 m. Spatial autocorrelation coefficients and correlograms of single and sub-sets of populations were statistically significant. The extent of within-population SGS was significantly negatively correlated with all genetic diversity parameters. Significant heterogeneity of within-population SGS was observed for 0-15 m and 61-90 m between core and peripheral populations. Average Sp, and gene flow distances were higher in peripheral (Sp = 0.023, σg = 135 m than in core (Sp = 0.014, σg = 109 m populations. However, the mean neighborhood size was higher in the core (Nb = 82 than in the peripheral (Nb = 48 populations. Conclusion Eastern white cedar populations have significant fine-scale genetic structure at short

The effects of a western spruce budworm outbreak on the dead wood component in relation to ownership in forests of eastern Oregon

Science.gov (United States)

David. Azuma

2010-01-01

Forest Inventory and Analysis data were used to investigate the effects of a severe western spruce budworm outbreak on the dead wood component of forests in 11 counties of eastern Oregon for two time periods. The ownership and the level of damage (as assessed by aerial surveys) affected the resulting down woody material and standing dead trees. The pattern of coarse...

A bijection between phylogenetic trees and plane oriented recursive trees

OpenAIRE

Prodinger, Helmut

2017-01-01

Phylogenetic trees are binary nonplanar trees with labelled leaves, and plane oriented recursive trees are planar trees with an increasing labelling. Both families are enumerated by double factorials. A bijection is constructed, using the respective representations a 2-partitions and trapezoidal words.

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.

General Reevaluation Report and Environmental Impact Statement for the Blanchard River, Ottawa, Ohio Flood Protection Project

Science.gov (United States)

1987-04-01

Black locust Black willow Honey locust Mulberry Slippery elm Box elder Cottonwood Multiflora rose Green ash Hackberry The U.S. Fish and Wildlife Service...flows in the Blanchard River at Ottawa. The Perry Street bridge was removed in 1951 and replaced by a new bridge at Elm Street that is less restrictive...flood plain. The present tree growth commonly consists of a second growth of spe- cies of elm , maple, and oak. All of the Blanchard River basin lies

Shifts in tree functional composition amplify the response of forest biomass to climate.

Science.gov (United States)

Zhang, Tao; Niinemets, Ülo; Sheffield, Justin; Lichstein, Jeremy W

2018-04-05

Forests have a key role in global ecosystems, hosting much of the world's terrestrial biodiversity and acting as a net sink for atmospheric carbon. These and other ecosystem services that are provided by forests may be sensitive to climate change as well as climate variability on shorter time scales (for example, annual to decadal). Previous studies have documented responses of forest ecosystems to climate change and climate variability, including drought-induced increases in tree mortality rates. However, relationships between forest biomass, tree species composition and climate variability have not been quantified across a large region using systematically sampled data. Here we use systematic forest inventories from the 1980s and 2000s across the eastern USA to show that forest biomass responds to decadal-scale changes in water deficit, and that this biomass response is amplified by concurrent changes in community-mean drought tolerance, a functionally important aspect of tree species composition. The amplification of the direct effects of water stress on biomass occurs because water stress tends to induce a shift in tree species composition towards species that are more tolerant to drought but are slower growing. These results demonstrate concurrent changes in forest species composition and biomass carbon storage across a large, systematically sampled region, and highlight the potential for climate-induced changes in forest ecosystems across the world, resulting from both direct effects of climate on forest biomass and indirect effects mediated by shifts in species composition.

Shifts in tree functional composition amplify the response of forest biomass to climate

Science.gov (United States)

Zhang, Tao; Niinemets, Ülo; Sheffield, Justin; Lichstein, Jeremy W.

2018-04-01

Forests have a key role in global ecosystems, hosting much of the world’s terrestrial biodiversity and acting as a net sink for atmospheric carbon. These and other ecosystem services that are provided by forests may be sensitive to climate change as well as climate variability on shorter time scales (for example, annual to decadal). Previous studies have documented responses of forest ecosystems to climate change and climate variability, including drought-induced increases in tree mortality rates. However, relationships between forest biomass, tree species composition and climate variability have not been quantified across a large region using systematically sampled data. Here we use systematic forest inventories from the 1980s and 2000s across the eastern USA to show that forest biomass responds to decadal-scale changes in water deficit, and that this biomass response is amplified by concurrent changes in community-mean drought tolerance, a functionally important aspect of tree species composition. The amplification of the direct effects of water stress on biomass occurs because water stress tends to induce a shift in tree species composition towards species that are more tolerant to drought but are slower growing. These results demonstrate concurrent changes in forest species composition and biomass carbon storage across a large, systematically sampled region, and highlight the potential for climate-induced changes in forest ecosystems across the world, resulting from both direct effects of climate on forest biomass and indirect effects mediated by shifts in species composition.

Single-Locus versus Multilocus Patterns of Local Adaptation to Climate in Eastern White Pine (Pinus strobus, Pinaceae.

Directory of Open Access Journals (Sweden)

Om P Rajora

Full Text Available Natural plant populations are often adapted to their local climate and environmental conditions, and populations of forest trees offer some of the best examples of this pattern. However, little empirical work has focused on the relative contribution of single-locus versus multilocus effects to the genetic architecture of local adaptation in plants/forest trees. Here, we employ eastern white pine (Pinus strobus to test the hypothesis that it is the inter-genic effects that primarily drive climate-induced local adaptation. The genetic structure of 29 range-wide natural populations of eastern white pine was determined in relation to local climatic factors using both a reference set of SSR markers, and SNPs located in candidate genes putatively involved in adaptive response to climate. Comparisons were made between marker sets using standard single-locus outlier analysis, single-locus and multilocus environment association analyses and a novel implementation of Population Graphs. Magnitudes of population structure were similar between the two marker sets. Outlier loci consistent with diversifying selection were rare for both SNPs and SSRs. However, genetic distances based on the multilocus among population covariances (cGD were significantly more correlated to climate, even after correcting for spatial effects, for SNPs as compared to SSRs. Coalescent simulations confirmed that the differences in mutation rates between SSRs and SNPs did not affect the topologies of the Population Graphs, and hence values of cGD and their correlations with associated climate variables. We conclude that the multilocus covariances among populations primarily reflect adaptation to local climate and environment in eastern white pine. This result highlights the complexity of the genetic architecture of adaptive traits, as well as the need to consider multilocus effects in studies of local adaptation.

New tree-ring evidence for the Late Glacial period from the northern pre-Alps in eastern Switzerland

Science.gov (United States)

Reinig, Frederick; Nievergelt, Daniel; Esper, Jan; Friedrich, Michael; Helle, Gerhard; Hellmann, Lena; Kromer, Bernd; Morganti, Sandro; Pauly, Maren; Sookdeo, Adam; Tegel, Willy; Treydte, Kerstin; Verstege, Anne; Wacker, Lukas; Büntgen, Ulf

2018-04-01

The rate and magnitude of temperature variability at the transition from the Last Glacial Maximum into the early Holocene represents a natural analog to current and predicted climate change. A limited number of high-resolution proxy archives, however, challenges our understanding of environmental conditions during this period. Here, we present combined dendrochronological and radiocarbon evidence from 253 newly discovered subfossil pine stumps from Zurich, Switzerland. The individual trees reveal ages of 41-506 years and were growing between the Allerød and Preboreal (∼13‧900-11‧300 cal BP). Together with previously collected pines from this region, this world's best preserved Late Glacial forest substantially improves the earliest part of the absolutely dated European tree-ring width chronology between 11‧300 and 11‧900 cal BP. Radiocarbon measurements from 65 Zurich pines between ∼12‧320 and 13‧950 cal BP provide a perspective to prolong the continuous European tree-ring record by another ∼2000 years into the Late Glacial era. These data will also be relevant for pinpointing the Laacher See volcanic eruption (∼12‧900 cal BP) and two major Alpine earthquakes (∼13‧770 and ∼11‧600 cal BP). In summary, this study emphasizes the importance of dating precision and multi-proxy comparison to disentangle environmental signals from methodological noise, particularly during periods of high climate variability but low data availability, such as the Younger Dryas cold spell (∼11‧700 and 12‧900 cal BP).

Assessment of fish populations and habitat on Oculina Bank, a deep-sea coral marine protected area off eastern Florida

OpenAIRE

Harter , Stacey L.; Ribera, Marta M.; Shepard, Andrew N.; Reed, John K.

2009-01-01

A portion of the Oculina Bank located off eastern Florida is a marine protected area (MPA) preserved for its dense populations of the ivory tree coral (Oculina varicosa), which provides important habitat for fish. Surveys of fish assemblages and benthic habitat were conducted inside and outside the MPA in 2003 and 2005 by using remotely operated vehicle video transects and digital still imagery. Fish species composition, biodiversity, and grouper densities were used to determine w...

IcyTree: rapid browser-based visualization for phylogenetic trees and networks.

Science.gov (United States)

Vaughan, Timothy G

2017-08-01

IcyTree is an easy-to-use application which can be used to visualize a wide variety of phylogenetic trees and networks. While numerous phylogenetic tree viewers exist already, IcyTree distinguishes itself by being a purely online tool, having a responsive user interface, supporting phylogenetic networks (ancestral recombination graphs in particular), and efficiently drawing trees that include information such as ancestral locations or trait values. IcyTree also provides intuitive panning and zooming utilities that make exploring large phylogenetic trees of many thousands of taxa feasible. IcyTree is a web application and can be accessed directly at http://tgvaughan.github.com/icytree . Currently supported web browsers include Mozilla Firefox and Google Chrome. IcyTree is written entirely in client-side JavaScript (no plugin required) and, once loaded, does not require network access to run. IcyTree is free software, and the source code is made available at http://github.com/tgvaughan/icytree under version 3 of the GNU General Public License. tgvaughan@gmail.com. © The Author(s) 2017. Published by Oxford University Press.

Assessing health literacy in the eastern and middle-eastern cultures

Directory of Open Access Journals (Sweden)

Satish Chandrasekhar Nair

2016-08-01

Full Text Available Abstract Background Health literacy is a term employed to assess the ability of people to meet the increasing demands related to health in a rapidly evolving society. Low health literacy can affect the social determinants of health, health outcomes and the use of healthcare services. The purpose of the study was to develop a survey construct to assess health literacy within the context of regional culture. Different socioeconomic status among the Eastern and Middle Eastern countries may restrict, health information access and utilization for those with low literacy. Methods By employing expert panel, Delphi technique, focus group methodologies, and pre-testing using participants (N = 900 from the UAE and India, a survey construct to the Eastern-Middle Eastern cultures was developed. Reliability was assessed using Cronbach’s α and validity using Factor analysis. Kiaser-Meyer-Olkin (KMO sampling adequacy and Bartlett’s tests were used to assess the strength of the relationship among the variables. Results Inclusion of non-health related items were found to be critical in the authentic assessment of health literacy in the Eastern and Middle Eastern population given the influence of social desirability. Thirty-two percentage of the original 19-item construct was eliminated by the focus group for reasons of relevance and impact for the local culture. Field pretesting participants from two countries, indicated overall construct reliability (Cronbach’s α =0.85, validity and consistency (KMO value of 0.92 and Bartlett’s test of sphericity was significant. Conclusion The Eastern-Middle Eastern Adult Health Literacy (EMAHL13, screening instrument is brief, simple, a useful indicator of whether or not a patient can read. It assessespatients’ ability to comprehend by distinguishing between health and non-health related items. The EMAHL13 will be a useful too for the reliable assessment of health literacy in countries, where culture plays a

Assessing health literacy in the eastern and middle-eastern cultures.

Science.gov (United States)

Nair, Satish Chandrasekhar; Satish, Karthyayani Priya; Sreedharan, Jayadevan; Ibrahim, Halah

2016-08-19

Health literacy is a term employed to assess the ability of people to meet the increasing demands related to health in a rapidly evolving society. Low health literacy can affect the social determinants of health, health outcomes and the use of healthcare services. The purpose of the study was to develop a survey construct to assess health literacy within the context of regional culture. Different socioeconomic status among the Eastern and Middle Eastern countries may restrict, health information access and utilization for those with low literacy. By employing expert panel, Delphi technique, focus group methodologies, and pre-testing using participants (N = 900) from the UAE and India, a survey construct to the Eastern-Middle Eastern cultures was developed. Reliability was assessed using Cronbach's α and validity using Factor analysis. Kiaser-Meyer-Olkin (KMO) sampling adequacy and Bartlett's tests were used to assess the strength of the relationship among the variables. Inclusion of non-health related items were found to be critical in the authentic assessment of health literacy in the Eastern and Middle Eastern population given the influence of social desirability. Thirty-two percentage of the original 19-item construct was eliminated by the focus group for reasons of relevance and impact for the local culture. Field pretesting participants from two countries, indicated overall construct reliability (Cronbach's α =0.85), validity and consistency (KMO value of 0.92 and Bartlett's test of sphericity was significant). The Eastern-Middle Eastern Adult Health Literacy (EMAHL13), screening instrument is brief, simple, a useful indicator of whether or not a patient can read. It assessespatients' ability to comprehend by distinguishing between health and non-health related items. The EMAHL13 will be a useful too for the reliable assessment of health literacy in countries, where culture plays a significant impact. This will be the first steptowards providing

Eastern Europe

International Nuclear Information System (INIS)

Baret, J.P.; Corcuff, A.; Jousten, M.; Cherie, J.B.; Gorge, X.; Augustin, X.; Belime, F.

1999-01-01

By its economical and political impact, nuclear energy has an important contribution the countries of Eastern Europe that goes beyond simple energy source. The most important challenge is to gain a safety culture. Improvements have been noted but the reactors safety must stay a priority of the international cooperation in Eastern Europe. The plan for the completion and improvement of Mochovce nuclear plant is described, the situation of Chernobyl and how to make the sarcophagus in safe is discussed, the experience of a french P.M.E. ( small and medium size firm) called Corys Tess that has chosen to position itself on the Eastern Europe nuclear market is related. (N.C.)

Impact of elephant on two woody trees, Boscia oleoides and Pappea capensis, in an arid thicket-Nama Karoo mosaic, Greater Addo Elephant National Park

Directory of Open Access Journals (Sweden)

Marietjie Landman

2014-11-01

Full Text Available Despite extensive evidence of the influences of elephant on woody trees in savannah habitats, effects on trees in the succulent thickets of the Eastern Cape are relatively poorly described. Our study investigates the role and intensity of elephant impacts on Pappea capensis and the relatively rare Boscia oleoides in an arid thicket-Nama Karoo mosaic habitat of the Greater Addo Elephant National Park. We show that roughly 19% of the B. oleoides and nearly half of the P. capensis individuals recorded showed signs of elephant impact. Elephant often toppled our study trees, and where these individuals were uprooted, mortalities occurred: B. oleoides ~ 44% of the impacted trees (4 individuals; P. capensis ~ 22% of the impacted trees (29 individuals. Conservation implications: Whilst this study is restricted by limited spatial and temporal replication, P. capensis mortalities caused by elephant occurred at a rate exceeding that of other processes. Our results provide insight into the severity of the measured changes and the need to reduce the impacts. However, it would be critically important to establish the specific driver of elephant–tree interactions before any management intervention is implemented.

TreeScaper: Visualizing and Extracting Phylogenetic Signal from Sets of Trees.

Science.gov (United States)

Huang, Wen; Zhou, Guifang; Marchand, Melissa; Ash, Jeremy R; Morris, David; Van Dooren, Paul; Brown, Jeremy M; Gallivan, Kyle A; Wilgenbusch, Jim C

2016-12-01

Modern phylogenomic analyses often result in large collections of phylogenetic trees representing uncertainty in individual gene trees, variation across genes, or both. Extracting phylogenetic signal from these tree sets can be challenging, as they are difficult to visualize, explore, and quantify. To overcome some of these challenges, we have developed TreeScaper, an application for tree set visualization as well as the identification of distinct phylogenetic signals. GUI and command-line versions of TreeScaper and a manual with tutorials can be downloaded from https://github.com/whuang08/TreeScaper/releases TreeScaper is distributed under the GNU General Public License. © The Author 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Flowering Trees

Indian Academy of Sciences (India)

IAS Admin

Flowering Trees. Ailanthus excelsa Roxb. (INDIAN TREE OF. HEAVEN) of Simaroubaceae is a lofty tree with large pinnately compound alternate leaves, which are ... inflorescences, unisexual and greenish-yellow. Fruits are winged, wings many-nerved. Wood is used in making match sticks. 1. Male flower; 2. Female flower.

Spatial epidemiology of eastern equine encephalitis in Florida

Directory of Open Access Journals (Sweden)

Vander Kelen Patrick T

2012-11-01

Full Text Available Abstract Background Eastern Equine Encephalitis virus (EEEV is an alphavirus with high pathogenicity in both humans and horses. Florida continues to have the highest occurrence of human cases in the USA, with four fatalities recorded in 2010. Unlike other states, Florida supports year-round EEEV transmission. This research uses GIS to examine spatial patterns of documented horse cases during 2005–2010 in order to understand the relationships between habitat and transmission intensity of EEEV in Florida. Methods Cumulative incidence rates of EEE in horses were calculated for each county. Two cluster analyses were performed using density-based spatial clustering of applications with noise (DBSCAN. The first analysis was based on regional clustering while the second focused on local clustering. Ecological associations of EEEV were examined using compositional analysis and Euclidean distance analysis to determine if the proportion or proximity of certain habitats played a role in transmission. Results The DBSCAN algorithm identified five distinct regional spatial clusters that contained 360 of the 438 horse cases. The local clustering resulted in 18 separate clusters containing 105 of the 438 cases. Both the compositional analysis and Euclidean distance analysis indicated that the top five habitats positively associated with horse cases were rural residential areas, crop and pastureland, upland hardwood forests, vegetated non-forested wetlands, and tree plantations. Conclusions This study demonstrates that in Florida tree plantations are a focus for epizootic transmission of EEEV. It appears both the abundance and proximity of tree plantations are factors associated with increased risk of EEE in horses and therefore humans. This association helps to explain why there is are spatially distinct differences in the amount of EEE horse cases across Florida.

Effectiveness of odor-baited trap trees for plum curculio (Coleoptera: Curculionidae) monitoring in commercial apple orchards in the northeast.

Science.gov (United States)

Piñero, Jaime C; Agnello, Arthur M; Tuttle, Arthur; Leskey, Tracy C; Faubert, Heather; Koehler, Glen; Los, Lorraine; Morin, Glenn; Leahy, Kathleen; Cooley, Daniel R; Prokopy, Ronald J

2011-10-01

The plum curculio, Conotrachelus nenuphar (Herbst), is a key pest of pome and stone fruit in eastern and central North America. For effective management of this insect pest in commercial apple (Malus spp.) orchards in the northeastern United States and Canada, one of the greatest challenges has been to determine the need for and timing of insecticide applications that will protect apple fruit from injury by adults. In a 2004-2005 study, we assessed the efficacy and economic viability of a reduced-risk integrated pest management strategy involving an odor-baited trap tree approach to determine need for and timing of insecticide use against plum curculio based on appearance of fresh egg-laying scars. Evaluations took place in commercial apple orchards in seven northeastern U.S. states. More specifically, we compared the trap-tree approach with three calendar-driven whole-block sprays and with heat-unit accumulation models that predict how long insecticide should be applied to orchard trees to prevent injury by plum curculio late in the season. Trap tree plots received a whole-plot insecticide spray by the time of petal fall, and succeeding sprays (if needed) were applied to peripheral-row trees only, depending on a threshold of one fresh plum curculio egg-laying scar out of 25 fruit sampled from a single trap tree. In both years, level of plum curculio injury to fruit sampled from perimeter-row, the most interior-row trees and whole-plot injury in trap tree plots did not differ significantly from that recorded in plots subject to conventional management or in plots managed using the heat-unit accumulation approach. The amount of insecticide used in trap tree plots was reduced at least by 43% compared with plots managed with the conventional approach. Advantages and potential pitfalls of the bio-based trap tree approach to plum curculio monitoring in apple orchards are discussed.

Mistletoe infection alters the transpiration flow path and suppresses water regulation of host trees during extreme events

Science.gov (United States)

Griebel, A.; Maier, C.; Barton, C. V.; Metzen, D.; Renchon, A.; Boer, M. M.; Pendall, E.

2017-12-01

Mistletoe is a globally distributed group of parasitic plants that infiltrates the vascular tissue of its host trees to acquire water, carbon and nutrients, making it a leading agent of biotic disturbance. Many mistletoes occur in water-limited ecosystems, thus mistletoe infection in combination with increased climatic stress may exacerbate water stress and potentially accelerate mortality rates of infected trees during extreme events. This is an emerging problem in Australia, as mistletoe distribution is increasing and clear links between mistletoe infection and mortality have been established. However, direct observations about how mistletoes alter host physiological processes during extreme events are rare, which impedes our understanding of mechanisms underlying increased tree mortality rates. We addressed this gap by continuously monitoring stem and branch sap flow and a range of leaf traits of infected and uninfected trees of two co-occurring eucalypt species during a severe heatwave in south-eastern Australia. We demonstrate that mistletoes' leaf water potentials were maintained 30% lower than hosts' to redirect the trees' transpiration flow path towards mistletoe leaves. Eucalypt leaves reduced water loss through stomatal regulation when atmospheric dryness exceeded 2 kPa, but the magnitude of stomatal regulation in non-infected eucalypts differed by species (between 40-80%). Remarkably, when infected, sap flow rates of stems and branches of both eucalypt species remained unregulated even under extreme atmospheric dryness (>8 kPa). Our observations indicate that excessive water use of mistletoes likely increases xylem cavitation rates in hosts during prolonged droughts and supports that hydraulic failure contributes to increased mortality of infected trees. Hence, in order to accurately model the contribution of biotic disturbances to tree mortality under a changing climate, it will be crucial to increase our process-based understanding of the interaction

Pollution and Climate Effects on Tree-Ring Nitrogen Isotopes

Science.gov (United States)

Savard, M. M.; Bégin, C.; Marion, J.; Smirnoff, A.

2009-04-01

BACKGROUND Monitoring of nitrous oxide concentration only started during the last 30 years in North America, but anthropogenic atmospheric nitrogen has been significantly emitted over the last 150 years. Can geochemical characteristics of tree rings be used to infer past changes in the nitrogen cycle of temperate regions? To address this question we use nitrogen stable isotopes in 125 years-long ring series from beech specimens (Fagus grandifolia) of the Georgian Bay Islands National Park (eastern Ontario), and pine (Pinus strobus) and beech trees of the Arboretum Morgan near Montreal (western Quebec). To evaluate the reliability of the N stable isotopes in wood treated for removal of soluble materials, we tested both tree species from the Montreal area. The reproducibility from tree to tree was excellent for both pine and beech trees, the isotopic trends were strongly concordant, and they were not influenced by the heartwood-sapwood transition zone. The coherence of changes of the isotopic series observed for the two species suggests that their tree-ring N isotopic values can serve as environmental indicator. RESULTS AND INTERPRETATION In Montreal and Georgian Bay, the N isotopes show strong and similar parallel agreement (Gleichlaufigkeit test) with the climatic parameters. So in fact, the short-term isotopic fluctuations correlate directly with summer precipitation and inversely with summer and spring temperature. A long-term decreasing isotope trend in Montreal indicates progressive changes in soil chemistry after 1951. A pedochemical change is also inferred for the Georgian Bay site on the basis of a positive N isotopic trend initiated after 1971. At both sites, the long-term ^15N series correlate with a proxy for NOx emissions (Pearson correlation), and carbon-isotope ring series suggest that the same trees have been impacted by phytotoxic pollutants (Savard et al., 2009a). We propose that the contrasted long-term nitrogen-isotope changes of Montreal and

Why do trees die? Characterizing the drivers of background tree mortality

Science.gov (United States)

Das, Adrian J.; Stephenson, Nathan L.; Davis, Kristin P.

2016-01-01

The drivers of background tree mortality rates—the typical low rates of tree mortality found in forests in the absence of acute stresses like drought—are central to our understanding of forest dynamics, the effects of ongoing environmental changes on forests, and the causes and consequences of geographical gradients in the nature and strength of biotic interactions. To shed light on factors contributing to background tree mortality, we analyzed detailed pathological data from 200,668 tree-years of observation and 3,729 individual tree deaths, recorded over a 13-yr period in a network of old-growth forest plots in California's Sierra Nevada mountain range. We found that: (1) Biotic mortality factors (mostly insects and pathogens) dominated (58%), particularly in larger trees (86%). Bark beetles were the most prevalent (40%), even though there were no outbreaks during the study period; in contrast, the contribution of defoliators was negligible. (2) Relative occurrences of broad classes of mortality factors (biotic, 58%; suppression, 51%; and mechanical, 25%) are similar among tree taxa, but may vary with tree size and growth rate. (3) We found little evidence of distinct groups of mortality factors that predictably occur together on trees. Our results have at least three sets of implications. First, rather than being driven by abiotic factors such as lightning or windstorms, the “ambient” or “random” background mortality that many forest models presume to be independent of tree growth rate is instead dominated by biotic agents of tree mortality, with potentially critical implications for forecasting future mortality. Mechanistic models of background mortality, even for healthy, rapidly growing trees, must therefore include the insects and pathogens that kill trees. Second, the biotic agents of tree mortality, instead of occurring in a few predictable combinations, may generally act opportunistically and with a relatively large degree of independence from

Flowering Trees

Indian Academy of Sciences (India)

Flowering Trees. Gyrocarpus americanus Jacq. (Helicopter Tree) of Hernandiaceae is a moderate size deciduous tree that grows to about 12 m in height with a smooth, shining, greenish-white bark. The leaves are ovate, rarely irregularly ... flowers which are unpleasant smelling. Fruit is a woody nut with two long thin wings.

Spatial distributions and enantiomeric signatures of DDT and its metabolites in tree bark from agricultural regions across China.

Science.gov (United States)

Niu, Lili; Xu, Chao; Zhang, Chunlong; Zhou, Yuting; Zhu, Siyu; Liu, Weiping

2017-10-01

Tree bark is considered as an effective passive sampler for estimating the atmospheric status of pollutants. In this study, we conducted a national scale tree bark sampling campaign across China. Concentration profiles revealed that Eastern China, especially the Jing-Jin-Ji region (including Hebei Province, Beijing and Tianjin) was a hot spot of bark DDT pollution. The enantioselective accumulation of o,p'-DDT was observed in most of the samples and 68% of them showed a preferential depletion of (+)-o,p'-DDT. These results suggest that DDTs in rural bark are likely from combined sources including historical technical DDTs and fresh dicofol usage. The tree bulk DDT levels were found to correlate with soil DDT concentrations, socioeconomy and PM 2.5 of the sampling sites. It thus becomes evident that the reemission from soils and subsequent atmospheric deposition were the major pathways leading to the accumulation of DDTs in bark. Based on a previously established bark-air partitioning model, the concentrations of DDTs in the air were estimated from measured concentrations in tree bark, and the results were comparable to those obtained by the use of passive sampling with polyurethane foam (PUF) disks. Our results demonstrate the feasibility of delineating the spatial variations in atmospheric concentration and tracing sources of DDTs by integrating the use of tree bark with enantiomeric analysis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Cache-Oblivious Search Trees via Binary Trees of Small Height

DEFF Research Database (Denmark)

Brodal, G.S.; Fagerberg, R.; Jacob, R.

2002-01-01

We propose a version of cache oblivious search trees which is simpler than the previous proposal of Bender, Demaine and Farach-Colton and has the same complexity bounds. In particular, our data structure avoids the use of weight balanced B-trees, and can be implemented as just a single array......, and range queries in worst case O(logB n + k/B) memory transfers, where k is the size of the output.The basic idea of our data structure is to maintain a dynamic binary tree of height log n+O(1) using existing methods, embed this tree in a static binary tree, which in turn is embedded in an array in a cache...... oblivious fashion, using the van Emde Boas layout of Prokop.We also investigate the practicality of cache obliviousness in the area of search trees, by providing an empirical comparison of different methods for laying out a search tree in memory....

Flowering Trees

Indian Academy of Sciences (India)

Flowering Trees. Boswellia serrata Roxb. ex Colebr. (Indian Frankincense tree) of Burseraceae is a large-sized deciduous tree that is native to India. Bark is thin, greenish-ash-coloured that exfoliates into smooth papery flakes. Stem exudes pinkish resin ... Fruit is a three-valved capsule. A green gum-resin exudes from the ...

Effects of Different Irrigation Programs on Fruit, Trunk Growth Rates, Quality and Yield of Grapefruit Trees

OpenAIRE

KANBER, Rıza; KÖKSAL, Harun; YAZAR, Attila; ÖZEKİCİ, Bülent; ÖNDER, Sermet

1999-01-01

Long-term field experiments were carried out between 1985 and 1988 to determine the effect of different irrigation intervals and pan coefficients on the fruit and trunk growth rates and yield of mature grapefruit trees grown in the Eastern Mediterranean Region of Turkey in a medium-light textured soil. Two different irrigation intervals (I 1 =15 and I 2 =25 days), and pan coefficients (k 1 =0.60 and k 2 =1.00) were used. Higher evapotranspiration values were obtained from the treatments with ...

Systolic trees and systolic language recognition by tree automata

Energy Technology Data Exchange (ETDEWEB)

Steinby, M

1983-01-01

K. Culik II, J. Gruska, A. Salomaa and D. Wood have studied the language recognition capabilities of certain types of systolically operating networks of processors (see research reports Cs-81-32, Cs-81-36 and Cs-82-01, Univ. of Waterloo, Ontario, Canada). In this paper, their model for systolic VLSI trees is formalised in terms of standard tree automaton theory, and the way in which some known facts about recognisable forests and tree transductions can be applied in VLSI tree theory is demonstrated. 13 references.

DupTree: a program for large-scale phylogenetic analyses using gene tree parsimony.

Science.gov (United States)

Wehe, André; Bansal, Mukul S; Burleigh, J Gordon; Eulenstein, Oliver

2008-07-01

DupTree is a new software program for inferring rooted species trees from collections of gene trees using the gene tree parsimony approach. The program implements a novel algorithm that significantly improves upon the run time of standard search heuristics for gene tree parsimony, and enables the first truly genome-scale phylogenetic analyses. In addition, DupTree allows users to examine alternate rootings and to weight the reconciliation costs for gene trees. DupTree is an open source project written in C++. DupTree for Mac OS X, Windows, and Linux along with a sample dataset and an on-line manual are available at http://genome.cs.iastate.edu/CBL/DupTree

Impacts of hydroelectric dams on alluvial riparian plant communities in Eastern Brazilian Amazonian.

Science.gov (United States)

Ferreira, Leandro Valle; Cunha, Denise A; Chaves, Priscilla P; Matos, Darley C L; Parolin, Pia

2013-09-01

The major rivers of the Amazon River basin and their biota are threatened by the planned construction of large hydroelectric dams that are expected to have strong impacts on floodplain plant communities. The present study presents forest inventories from three floodplain sites colonized by alluvial riparian vegetation in the Tapajós, Xingu and Tocantins River basins in eastern Amazonian. Results indicate that tree species of the highly specialized alluvial riparian vegetation are clearly distinct among the three river basins, although they are not very distinct from each other and environmental constraints are very similar. With only 6 of 74 species occurring in all three inventories, most tree and shrub species are restricted to only one of the rivers, indicating a high degree of local distribution. Different species occupy similar environmental niches, making these fragile riparian formations highly valuable. Conservation plans must consider species complementarily when decisions are made on where to place floodplain forest conservation units to avoid the irreversible loss of unique alluvial riparian vegetation biodiversity.

Impacts of hydroelectric dams on alluvial riparian plant communities in eastern Brazilian Amazonian

Directory of Open Access Journals (Sweden)

LEANDRO VALLE FERREIRA

2013-09-01

Full Text Available The major rivers of the Amazon River basin and their biota are threatened by the planned construction of large hydroelectric dams that are expected to have strong impacts on floodplain plant communities. The present study presents forest inventories from three floodplain sites colonized by alluvial riparian vegetation in the Tapajós, Xingu and Tocantins River basins in eastern Amazonian. Results indicate that tree species of the highly specialized alluvial riparian vegetation are clearly distinct among the three river basins, although they are not very distinct from each other and environmental constraints are very similar. With only 6 of 74 species occurring in all three inventories, most tree and shrub species are restricted to only one of the rivers, indicating a high degree of local distribution. Different species occupy similar environmental niches, making these fragile riparian formations highly valuable. Conservation plans must consider species complementarily when decisions are made on where to place floodplain forest conservation units to avoid the irreversible loss of unique alluvial riparian vegetation biodiversity.

Flowering Trees

Indian Academy of Sciences (India)

More Details Fulltext PDF. Volume 8 Issue 8 August 2003 pp 112-112 Flowering Trees. Zizyphus jujuba Lam. of Rhamnaceae · More Details Fulltext PDF. Volume 8 Issue 9 September 2003 pp 97-97 Flowering Trees. Moringa oleifera · More Details Fulltext PDF. Volume 8 Issue 10 October 2003 pp 100-100 Flowering Trees.

Embedding complete ternary tree in hypercubes using AVL trees

NARCIS (Netherlands)

S.A. Choudum; I. Raman (Indhumathi)

2008-01-01

htmlabstractA complete ternary tree is a tree in which every non-leaf vertex has exactly three children. We prove that a complete ternary tree of height h, TTh, is embeddable in a hypercube of dimension . This result coincides with the result of [2]. However, in this paper, the embedding utilizes

Ghost-tree: creating hybrid-gene phylogenetic trees for diversity analyses.

Science.gov (United States)

Fouquier, Jennifer; Rideout, Jai Ram; Bolyen, Evan; Chase, John; Shiffer, Arron; McDonald, Daniel; Knight, Rob; Caporaso, J Gregory; Kelley, Scott T

2016-02-24

Fungi play critical roles in many ecosystems, cause serious diseases in plants and animals, and pose significant threats to human health and structural integrity problems in built environments. While most fungal diversity remains unknown, the development of PCR primers for the internal transcribed spacer (ITS) combined with next-generation sequencing has substantially improved our ability to profile fungal microbial diversity. Although the high sequence variability in the ITS region facilitates more accurate species identification, it also makes multiple sequence alignment and phylogenetic analysis unreliable across evolutionarily distant fungi because the sequences are hard to align accurately. To address this issue, we created ghost-tree, a bioinformatics tool that integrates sequence data from two genetic markers into a single phylogenetic tree that can be used for diversity analyses. Our approach starts with a "foundation" phylogeny based on one genetic marker whose sequences can be aligned across organisms spanning divergent taxonomic groups (e.g., fungal families). Then, "extension" phylogenies are built for more closely related organisms (e.g., fungal species or strains) using a second more rapidly evolving genetic marker. These smaller phylogenies are then grafted onto the foundation tree by mapping taxonomic names such that each corresponding foundation-tree tip would branch into its new "extension tree" child. We applied ghost-tree to graft fungal extension phylogenies derived from ITS sequences onto a foundation phylogeny derived from fungal 18S sequences. Our analysis of simulated and real fungal ITS data sets found that phylogenetic distances between fungal communities computed using ghost-tree phylogenies explained significantly more variance than non-phylogenetic distances. The phylogenetic metrics also improved our ability to distinguish small differences (effect sizes) between microbial communities, though results were similar to non

Trees are good, but…

Science.gov (United States)

E.G. McPherson; F. Ferrini

2010-01-01

We know that “trees are good,” and most people believe this to be true. But if this is so, why are so many trees neglected, and so many tree wells empty? An individual’s attitude toward trees may result from their firsthand encounters with specific trees. Understanding how attitudes about trees are shaped, particularly aversion to trees, is critical to the business of...

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.

Sparse trees and shrubs confers a high biodiversity to pastures: Case study on spiders from Transylvania.

Science.gov (United States)

Gallé, Róbert; Urák, István; Nikolett, Gallé-Szpisjak; Hartel, Tibor

2017-01-01

The integration of food production and biodiversity conservation represents a key challenge for sustainability. Several studies suggest that even small structural elements in the landscape can make a substantial contribution to the overall biodiversity value of the agricultural landscapes. Pastures can have high biodiversity potential. However, their intensive and monofunctional use typically erodes its natural capital, including biodiversity. Here we address the ecological value of fine scale structural elements represented by sparsely scattered trees and shrubs for the spider communities in a moderately intensively grazed pasture in Transylvania, Eastern Europe. The pasture was grazed with sheep, cattle and buffalo (ca 1 Livestock Unit ha-1) and no chemical fertilizers were applied. Sampling sites covered the open pasture as well as the existing fine-scale heterogeneity created by scattered trees and shrub. 40 sampling locations each being represented by three 1 m2 quadrats were situated in a stratified design while assuring spatial independency of sampling locations. We identified 140 species of spiders, out of which 18 were red listed and four were new for the Romanian fauna. Spider species assemblages of open pasture, scattered trees, trees and shrubs and the forest edge were statistically distinct. Our study shows that sparsely scattered mature woody vegetation and shrubs substantially increases the ecological value of managed pastures. The structural complexity provided by scattered trees and shrubs makes possible the co-occurrence of high spider diversity with a moderately high intensity grazing possible in this wood-pasture. Our results are in line with recent empirical research showing that sparse trees and shrubs increases the biodiversity potential of pastures managed for commodity production.

Shedding light on tree growth : ring analysis of juvenile tropical trees

NARCIS (Netherlands)

Soliz Gamboa, C.C.

2010-01-01

In the understory of tropical forests light is believed to be the main limiting growth factor for the newly established trees. Trees growing in shade of the understory may experience periods of slow radial growth. It is expected that gaps created by tree or branch fall will provoke tree growth

Transpiration and stomatal conductance in a young secondary tropical montane forest: contrasts between native trees and invasive understorey shrubs.

Science.gov (United States)

Ghimire, Chandra Prasad; Bruijnzeel, L Adrian; Lubczynski, Maciek W; Zwartendijk, Bob W; Odongo, Vincent Omondi; Ravelona, Maafaka; van Meerveld, H J Ilja

2018-04-21

It has been suggested that vigorous secondary tropical forests can have very high transpiration rates, but sap flow and stomatal conductance dynamics of trees and shrubs in these forests are understudied. In an effort to address this knowledge gap, sap flow (thermal dissipation method, 12 trees) and stomatal conductance (porometry, six trees) were measured for young (5-7 years) Psiadia altissima (DC.) Drake trees, a widely occurring species dominating young regrowth following abandonment of swidden agriculture in upland eastern Madagascar. In addition, stomatal conductance (gs) was determined for three individuals of two locally common invasive shrubs (Lantana camara L. and Rubus moluccanus L.) during three periods with contrasting soil moisture conditions. Values of gs for the three investigated species were significantly higher and more sensitive to climatic conditions during the wet period compared with the dry period. Further, gs of the understorey shrubs was much more sensitive to soil moisture content than that of the trees. Tree transpiration rates (Ec) were relatively stable during the dry season and were only affected somewhat by soil water content at the end of the dry season, suggesting the trees had continued access to soil water despite drying out of the topsoil. The Ec exhibited a plateau-shaped relation with vapour pressure deficit (VPD), which was attributed to stomatal closure at high VPD. Vapour pressure deficit was the major driver of variation in Ec, during both the wet and the dry season. Overall water use of the trees was modest, possibly reflecting low site fertility after three swidden cultivation cycles. The observed contrast in gs response to soil water and climatic conditions for the trees and shrubs underscores the need to take root distributions into account when modelling transpiration from regenerating tropical forests.

Inferring species trees from incongruent multi-copy gene trees using the Robinson-Foulds distance

Science.gov (United States)

2013-01-01

Background Constructing species trees from multi-copy gene trees remains a challenging problem in phylogenetics. One difficulty is that the underlying genes can be incongruent due to evolutionary processes such as gene duplication and loss, deep coalescence, or lateral gene transfer. Gene tree estimation errors may further exacerbate the difficulties of species tree estimation. Results We present a new approach for inferring species trees from incongruent multi-copy gene trees that is based on a generalization of the Robinson-Foulds (RF) distance measure to multi-labeled trees (mul-trees). We prove that it is NP-hard to compute the RF distance between two mul-trees; however, it is easy to calculate this distance between a mul-tree and a singly-labeled species tree. Motivated by this, we formulate the RF problem for mul-trees (MulRF) as follows: Given a collection of multi-copy gene trees, find a singly-labeled species tree that minimizes the total RF distance from the input mul-trees. We develop and implement a fast SPR-based heuristic algorithm for the NP-hard MulRF problem. We compare the performance of the MulRF method (available at http://genome.cs.iastate.edu/CBL/MulRF/) with several gene tree parsimony approaches using gene tree simulations that incorporate gene tree error, gene duplications and losses, and/or lateral transfer. The MulRF method produces more accurate species trees than gene tree parsimony approaches. We also demonstrate that the MulRF method infers in minutes a credible plant species tree from a collection of nearly 2,000 gene trees. Conclusions Our new phylogenetic inference method, based on a generalized RF distance, makes it possible to quickly estimate species trees from large genomic data sets. Since the MulRF method, unlike gene tree parsimony, is based on a generic tree distance measure, it is appealing for analyses of genomic data sets, in which many processes such as deep coalescence, recombination, gene duplication and losses as

A long-term vegetation history of the Mojave-Colorado Desert ecotone at Joshua Tree National Park

Science.gov (United States)

Holmgren, Camille A.; Betancourt, Julio L.; Rylander, Kate A.

2010-01-01

Thirty-eight dated packrat middens were collected from upper desert (930–1357 m) elevations within Joshua Tree National Park near the ecotone between the Mojave Desert and Colorado Desert, providing a 30 ka record of vegetation change with remarkably even coverage for the last 15 ka. This record indicates that vegetation was relatively stable, which may reflect the lack of invasion by extralocal species during the late glacial and the early establishment and persistence of many desert scrub elements. Many of the species found in the modern vegetation assemblages were present by the early Holocene, as indicated by increasing Sørenson's Similarity Index values. C4 grasses and summer-flowering annuals arrived later at Joshua Tree National Park in the early Holocene, suggesting a delayed onset of warm-season monsoonal precipitation compared to other Sonoran Desert and Chihuahuan Desert localities to the east, where summer rains and C4 grasses persisted through the last glacial–interglacial cycle. This would suggest that contemporary flow of monsoonal moisture into eastern California is secondary to the core processes of the North American Monsoon, which remained intact throughout the late Quaternary. In the Holocene, northward displacement of the jet stream, in both summer and winter, allowed migration of the subtropical ridge as far north as southern Idaho and the advection of monsoonal moisture both westward into eastern California and northward into the southern Great Basin and Colorado Plateau.

A systems biology, whole-genome association analysis of the molecular regulation of biomass growth and composition in Populus deltoides

Energy Technology Data Exchange (ETDEWEB)

Kirst, Matias [Univ. of Florida, Gainesville, FL (United States)

2014-04-14

Poplars trees are well suited for biofuel production due to their fast growing habit, favorable wood composition and adaptation to a broad range of environments. The availability of a reference genome sequence, ease of vegetative propagation and availability of transformation methods also make poplar an ideal model for the study of wood formation and biomass growth in woody, perennial plants. The objective of this project was to conduct a genome-wide association genetics study to identify genes that regulate bioenergy traits in Populus deltoides (eastern cottonwood). Populus deltoides is a genetically diverse keystone forest species in North America and an important short rotation woody crop for the bioenergy industry. We searched for associations between eight growth and wood composition traits and common and low-frequency single-nucleotide polymorphisms (SNPs) detected by targeted resequencing of 18,153 genes in a population of 391 unrelated individuals. To increase power to detect associations with low-frequency variants, multiple-marker association tests were used in combination with single-marker association tests. Significant associations were discovered for all phenotypes and are indicative that low-frequency polymorphisms contribute to phenotypic variance of several bioenergy traits. These polymorphism are critical tools for the development of specialized plant feedstocks for bioenergy.

A systems biology, whole-genome association analysis of the molecular regulation of biomass growth and composition in Populus deltoides

Energy Technology Data Exchange (ETDEWEB)

Kirst, Matias [Univ. of Florida, Gainesville, FL (United States)

2015-04-15

Poplars trees are well suited for biofuel production due to their fast growing habit, favorable wood composition and adaptation to a broad range of environments. The availability of a reference genome sequence, ease of vegetative propagation and availability of transformation methods also make poplar an ideal model for the study of wood formation and biomass growth in woody, perennial plants. The objective of this project was to conduct a genome-wide association genetics study to identify genes that regulate bioenergy traits in Populus deltoides (eastern cottonwood). Populus deltoides is a genetically diverse keystone forest species in North America and an important short rotation woody crop for the bioenergy industry. We searched for associations between eight growth and wood composition traits and common and low-frequency single-nucleotide polymorphisms (SNPs) detected by targeted resequencing of 18,153 genes in a population of 391 unrelated individuals. To increase power to detect associations with low-frequency variants, multiple-marker association tests were used in combination with single-marker association tests. Significant associations were discovered for all phenotypes and are indicative that low-frequency polymorphisms contribute to phenotypic variance of several bioenergy traits. These polymorphism are critical tools for the development of specialized plant feedstocks for bioenergy.

New tree-ring evidence for the Late Glacial period from the northern pre-Alps in eastern Switzerland

Czech Academy of Sciences Publication Activity Database

Reinig, F.; Nievergelt, D.; Esper, J.; Friedrich, M.; Helle, G.; Hellmann, L.; Kromer, B.; Morganti, S.; Pauly, M.; Sookdeo, A.; Tegel, W.; Treydte, K.; Verstege, A.; Wacker, L.; Büntgen, Ulf

2018-01-01

Roč. 186, APR (2018), s. 215-224 ISSN 0277-3791 Keywords : new-zealand kauri * laacher see volcano * ice-core records * radiocarbon calibration * central-europe * cal bp * southern-hemisphere * last deglaciation * hohenheim oak * climate * Central Europe * Dendrochronology * Late Glacial * Paleoclimatology * Radiocarbon * Subfossil wood * Switzerland * Tree rings * Younger Dryas Impact factor: 4.797, year: 2016

Groundwater decline and tree change in floodplain landscapes: Identifying non-linear threshold responses in canopy condition

Directory of Open Access Journals (Sweden)

J. Kath

2014-12-01

Full Text Available Groundwater decline is widespread, yet its implications for natural systems are poorly understood. Previous research has revealed links between groundwater depth and tree condition; however, critical thresholds which might indicate ecological ‘tipping points’ associated with rapid and potentially irreversible change have been difficult to quantify. This study collated data for two dominant floodplain species, Eucalyptus camaldulensis (river red gum and E. populnea (poplar box from 118 sites in eastern Australia where significant groundwater decline has occurred. Boosted regression trees, quantile regression and Threshold Indicator Taxa Analysis were used to investigate the relationship between tree condition and groundwater depth. Distinct non-linear responses were found, with groundwater depth thresholds identified in the range from 12.1 m to 22.6 m for E. camaldulensis and 12.6 m to 26.6 m for E. populnea beyond which canopy condition declined abruptly. Non-linear threshold responses in canopy condition in these species may be linked to rooting depth, with chronic groundwater decline decoupling trees from deep soil moisture resources. The quantification of groundwater depth thresholds is likely to be critical for management aimed at conserving groundwater dependent biodiversity. Identifying thresholds will be important in regions where water extraction and drying climates may contribute to further groundwater decline. Keywords: Canopy condition, Dieback, Drought, Tipping point, Ecological threshold, Groundwater dependent ecosystems

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.

76 FR 49527 - Supplemental Environmental Impact Statement; Cottonwood and Watonwan Counties, Minnesota

Science.gov (United States)

2011-08-10

... facility: (1) Just west of the City of St. James to the eastern edge of the City of Butterfield, (2) western edge of the City of Butterfield to just east of the city of Mountain Lake, and (3) just west of... comment period. Public notice will be give for the time and place of the hearing. A final Supplemental EIS...

A review of the siricid woodwasps and their Ibaliid parasitoids (Hymenoptera: Siricidae, Ibaliidae) in the Eastern United States, with emphasis on the Mid-Atlantic Region

Science.gov (United States)

David R. Smith; Nathan M. Schiff

2002-01-01

Keys are presented for the five genera and 15 species of adult Siricidae and one genus and two species of their parasitoids of the family Ibaliidae that occur in or may be adventive in the Eastern United States. Sircid larvae are wood borers in conifers and broadleafed trees. Notes on their biology, fungal symbionts, distributions, and host associations are given. Data...

Spectra of chemical trees

International Nuclear Information System (INIS)

Balasubramanian, K.

1982-01-01

A method is developed for obtaining the spectra of trees of NMR and chemical interests. The characteristic polynomials of branched trees can be obtained in terms of the characteristic polynomials of unbranched trees and branches by pruning the tree at the joints. The unbranched trees can also be broken down further until a tree containing just two vertices is obtained. The effectively reduces the order of the secular determinant of the tree used at the beginning to determinants of orders atmost equal to the number of vertices in the branch containing the largest number of vertices. An illustrative example of a NMR graph is given for which the 22 x 22 secular determinant is reduced to determinants of orders atmost 4 x 4 in just the second step of the algorithm. The tree pruning algorithm can be applied even to trees with no symmetry elements and such a factoring can be achieved. Methods developed here can be elegantly used to find if two trees are cospectral and to construct cospectral trees

MeshTree: A Delay optimised Overlay Multicast Tree Building Protocol

OpenAIRE

Tan, Su-Wei; Waters, A. Gill; Crawford, John

2005-01-01

We study decentralised low delay degree-constrained overlay multicast tree construction for single source real-time applications. This optimisation problem is NP-hard even if computed centrally. We identify two problems in traditional distributed solutions, namely the greedy problem and delay-cost trade-off. By offering solutions to these problems, we propose a new self-organising distributed tree building protocol called MeshTree. The main idea is to embed the delivery tree in a degree-bound...

Minimum variance rooting of phylogenetic trees and implications for species tree reconstruction.

Science.gov (United States)

Mai, Uyen; Sayyari, Erfan; Mirarab, Siavash

2017-01-01

Phylogenetic trees inferred using commonly-used models of sequence evolution are unrooted, but the root position matters both for interpretation and downstream applications. This issue has been long recognized; however, whether the potential for discordance between the species tree and gene trees impacts methods of rooting a phylogenetic tree has not been extensively studied. In this paper, we introduce a new method of rooting a tree based on its branch length distribution; our method, which minimizes the variance of root to tip distances, is inspired by the traditional midpoint rerooting and is justified when deviations from the strict molecular clock are random. Like midpoint rerooting, the method can be implemented in a linear time algorithm. In extensive simulations that consider discordance between gene trees and the species tree, we show that the new method is more accurate than midpoint rerooting, but its relative accuracy compared to using outgroups to root gene trees depends on the size of the dataset and levels of deviations from the strict clock. We show high levels of error for all methods of rooting estimated gene trees due to factors that include effects of gene tree discordance, deviations from the clock, and gene tree estimation error. Our simulations, however, did not reveal significant differences between two equivalent methods for species tree estimation that use rooted and unrooted input, namely, STAR and NJst. Nevertheless, our results point to limitations of existing scalable rooting methods.

Discovery of Walnut Twig Beetle, Pityophthorus juglandis, Associated with Forested Black Walnut, Juglans nigra, in the Eastern U.S.

Directory of Open Access Journals (Sweden)

Gregory J. Wiggins

2014-05-01

Full Text Available Thousand cankers disease (TCD is an insect-mediated disease of walnut trees (Juglans spp. involving walnut twig beetle (Pityophthorus juglandis and a fungal pathogen (Geosmithia morbida. Although first documented on walnut species in the western U.S., TCD is now found on black walnut (J. nigra in five states in the eastern U.S. Most collections of P. juglandis or G. morbida are from trees in agriculturally- or residentially-developed landscapes. In 2013, 16 pheromone-baited funnel traps were deployed in or near black walnuts in forested conditions to assess the risk of infestation of forested trees by P. juglandis. Four of the 16 funnel traps collected adult P. juglandis from three forested areas (one in North Carolina and two in Tennessee. These collections, while in forested settings, may still be strongly influenced by human activities. The greatest number of P. juglandis (n = 338 was collected from a forested location in an urbanized area near a known TCD-positive tree. The other two forested locations where P. juglandis (n = 3 was collected were in areas where camping is common, and infested firewood may have introduced P. juglandis unintentionally into the area. Future studies to assess P. juglandis on more isolated forested walnuts are planned.

Quantifying geomorphic controls on riparian forest dynamics using a linked physical-biological model: implications for river corridor conservation

Science.gov (United States)

Stella, J. C.; Harper, E. B.; Fremier, A. K.; Hayden, M. K.; Battles, J. J.

2009-12-01

In high-order alluvial river systems, physical factors of flooding and channel migration are particularly important drivers of riparian forest dynamics because they regulate habitat creation, resource fluxes of water, nutrients and light that are critical for growth, and mortality from fluvial disturbance. Predicting vegetation composition and dynamics at individual sites in this setting is challenging, both because of the stochastic nature of the flood regime and the spatial variability of flood events. Ecological models that correlate environmental factors with species’ occurrence and abundance (e.g., ’niche models’) often work well in infrequently-disturbed upland habitats, but are less useful in river corridors and other dynamic zones where environmental conditions fluctuate greatly and selection pressures on disturbance-adapted organisms are complex. In an effort to help conserve critical riparian forest habitat along the middle Sacramento River, CA, we are taking a mechanistic approach to quantify linkages between fluvial and biotic processes for Fremont cottonwood (Populus fremontii), a keystone pioneer tree in dryland rivers ecosystems of the U.S. Southwest. To predict the corridor-wide population effects of projected changes to the disturbance regime from flow regulation, climate change, and landscape modifications, we have coupled a physical model of channel meandering with a patch-based population model that incorporates the climatic, hydrologic, and topographic factors critical for tree recruitment and survival. We employed these linked simulations to study the relative influence of the two most critical habitat types--point bars and abandoned channels--in sustaining the corridor-wide cottonwood population over a 175-year period. The physical model uses discharge data and channel planform to predict the spatial distribution of new habitat patches; the population model runs on top of this physical template to track tree colonization and survival on

TreePlus: interactive exploration of networks with enhanced tree layouts.

Science.gov (United States)

Lee, Bongshin; Parr, Cynthia S; Plaisant, Catherine; Bederson, Benjamin B; Veksler, Vladislav D; Gray, Wayne D; Kotfila, Christopher

2006-01-01

Despite extensive research, it is still difficult to produce effective interactive layouts for large graphs. Dense layout and occlusion make food webs, ontologies, and social networks difficult to understand and interact with. We propose a new interactive Visual Analytics component called TreePlus that is based on a tree-style layout. TreePlus reveals the missing graph structure with visualization and interaction while maintaining good readability. To support exploration of the local structure of the graph and gathering of information from the extensive reading of labels, we use a guiding metaphor of "Plant a seed and watch it grow." It allows users to start with a node and expand the graph as needed, which complements the classic overview techniques that can be effective at (but often limited to) revealing clusters. We describe our design goals, describe the interface, and report on a controlled user study with 28 participants comparing TreePlus with a traditional graph interface for six tasks. In general, the advantage of TreePlus over the traditional interface increased as the density of the displayed data increased. Participants also reported higher levels of confidence in their answers with TreePlus and most of them preferred TreePlus.

Refining discordant gene trees.

Science.gov (United States)

Górecki, Pawel; Eulenstein, Oliver

2014-01-01

Evolutionary studies are complicated by discordance between gene trees and the species tree in which they evolved. Dealing with discordant trees often relies on comparison costs between gene and species trees, including the well-established Robinson-Foulds, gene duplication, and deep coalescence costs. While these costs have provided credible results for binary rooted gene trees, corresponding cost definitions for non-binary unrooted gene trees, which are frequently occurring in practice, are challenged by biological realism. We propose a natural extension of the well-established costs for comparing unrooted and non-binary gene trees with rooted binary species trees using a binary refinement model. For the duplication cost we describe an efficient algorithm that is based on a linear time reduction and also computes an optimal rooted binary refinement of the given gene tree. Finally, we show that similar reductions lead to solutions for computing the deep coalescence and the Robinson-Foulds costs. Our binary refinement of Robinson-Foulds, gene duplication, and deep coalescence costs for unrooted and non-binary gene trees together with the linear time reductions provided here for computing these costs significantly extends the range of trees that can be incorporated into approaches dealing with discordance.

Concordance between phylogeographical and biogeographical patterns in the Brazilian Cerrado: diversification of the endemic tree Dalbergia miscolobium (Fabaceae).

Science.gov (United States)

Novaes, Renan Milagres Lage; Ribeiro, Renata Acácio; Lemos-Filho, José Pires; Lovato, Maria Bernadete

2013-01-01

Few studies have addressed the phylogeography of species of the Cerrado, the largest savanna biome of South America. Here we aimed to investigate the phylogeographical structure of Dalbergia miscolobium, a widespread tree from the Cerrado, and to verify its concordance with plant phylogeographical and biogeographical patterns so far described. A total of 287 individuals from 32 populations were analyzed by sequencing the trnL intron of the chloroplast DNA and the internal transcribed spacer of the nuclear ribosomal DNA. Analysis of population structure and tests of population expansion were performed and the time of divergence of haplotypes was estimated. Twelve and 27 haplotypes were identified in the cpDNA and nrDNA data, respectively. The star-like network configuration and the mismatch distributions indicated a recent spatial and demographic expansion of the species. Consistent with previous tree phylogeographical studies of Cerrado trees, the cpDNA also suggested a recent expansion towards the southern Cerrado. The diversity of D. miscolobium was widespread but high levels of genetic diversity were found in the Central Eastern and in the southern portion of Central Western Cerrado. The combined analysis of cpDNA and nrDNA supported a phylogeographic structure into seven groups. The phylogeographical pattern showed many concordances with biogeographical and phylogeographical studies in the Cerrado, mainly with the Cerrado phytogeographic provinces superimposed to our sampling area. The data reinforced the uniqueness of Northeastern and Southeastern Cerrados and the differentiation between Eastern and Western Central Cerrados. The recent diversification of the species (estimated between the Pliocene and the Pleistocene) and the 'genealogical concordances' suggest that a shared and persistent pattern of species diversification might have been present in the Cerrado over time. This is the first time that an extensive 'genealogical concordance' between

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...

TreeFam: a curated database of phylogenetic trees of animal gene families

DEFF Research Database (Denmark)

Li, Heng; Coghlan, Avril; Ruan, Jue

2006-01-01

TreeFam is a database of phylogenetic trees of gene families found in animals. It aims to develop a curated resource that presents the accurate evolutionary history of all animal gene families, as well as reliable ortholog and paralog assignments. Curated families are being added progressively......, based on seed alignments and trees in a similar fashion to Pfam. Release 1.1 of TreeFam contains curated trees for 690 families and automatically generated trees for another 11 646 families. These represent over 128 000 genes from nine fully sequenced animal genomes and over 45 000 other animal proteins...

Net carbon flux of dead wood in forests of the Eastern US.

Science.gov (United States)

Woodall, C W; Russell, M B; Walters, B F; D'Amato, A W; Fraver, S; Domke, G M

2015-03-01

Downed dead wood (DDW) in forest ecosystems is a C pool whose net flux is governed by a complex of natural and anthropogenic processes and is critical to the management of the entire forest C pool. As empirical examination of DDW C net flux has rarely been conducted across large scales, the goal of this study was to use a remeasured inventory of DDW C and ancillary forest attributes to assess C net flux across forests of the Eastern US. Stocks associated with large fine woody debris (diameter 2.6-7.6 cm) decreased over time (-0.11 Mg ha(-1) year(-1)), while stocks of larger-sized coarse DDW increased (0.02 Mg ha(-1) year(-1)). Stocks of total DDW C decreased (-0.14 Mg ha(-1) year(-1)), while standing dead and live tree stocks both increased, 0.01 and 0.44 Mg ha(-1) year(-1), respectively. The spatial distribution of DDW C stock change was highly heterogeneous with random forests model results indicating that management history, live tree stocking, natural disturbance, and growing degree days only partially explain stock change. Natural disturbances drove substantial C transfers from the live tree pool (≈-4 Mg ha(-1) year(-1)) to the standing dead tree pool (≈3 Mg ha(-1) year(-1)) with only a minimal increase in DDW C stocks (≈1 Mg ha(-1) year(-1)) in lower decay classes, suggesting a delayed transfer of C to the DDW pool. The assessment and management of DDW C flux is complicated by the diversity of natural and anthropogenic forces that drive their dynamics with the scale and timing of flux among forest C pools remaining a large knowledge gap.

Tree-space statistics and approximations for large-scale analysis of anatomical trees

DEFF Research Database (Denmark)

Feragen, Aasa; Owen, Megan; Petersen, Jens

2013-01-01

parametrize the relevant parts of tree-space well. Using the developed approximate statistics, we illustrate how the structure and geometry of airway trees vary across a population and show that airway trees with Chronic Obstructive Pulmonary Disease come from a different distribution in tree-space than...

Relating phylogenetic trees to transmission trees of infectious disease outbreaks.

Science.gov (United States)

Ypma, Rolf J F; van Ballegooijen, W Marijn; Wallinga, Jacco

2013-11-01

Transmission events are the fundamental building blocks of the dynamics of any infectious disease. Much about the epidemiology of a disease can be learned when these individual transmission events are known or can be estimated. Such estimations are difficult and generally feasible only when detailed epidemiological data are available. The genealogy estimated from genetic sequences of sampled pathogens is another rich source of information on transmission history. Optimal inference of transmission events calls for the combination of genetic data and epidemiological data into one joint analysis. A key difficulty is that the transmission tree, which describes the transmission events between infected hosts, differs from the phylogenetic tree, which describes the ancestral relationships between pathogens sampled from these hosts. The trees differ both in timing of the internal nodes and in topology. These differences become more pronounced when a higher fraction of infected hosts is sampled. We show how the phylogenetic tree of sampled pathogens is related to the transmission tree of an outbreak of an infectious disease, by the within-host dynamics of pathogens. We provide a statistical framework to infer key epidemiological and mutational parameters by simultaneously estimating the phylogenetic tree and the transmission tree. We test the approach using simulations and illustrate its use on an outbreak of foot-and-mouth disease. The approach unifies existing methods in the emerging field of phylodynamics with transmission tree reconstruction methods that are used in infectious disease epidemiology.

ABOVEGROUND BIOMASS DISTRIBUTION OF US EASTERN HARDWOOD FORESTS AND THE USE OF LARGE TREES AS AN INDICATOR OF FOREST DEVELOPMENT

Science.gov (United States)

Past clearing and harvesting of the deciduous hardwood forests of eastern USA released large amount of carbon dioxide into the atmosphere, but through recovery and regrowth these forests are now accumulating atmospheric carbon (C). This study examined quantities and distribution ...

Decision-Tree Program

Science.gov (United States)

Buntine, Wray

1994-01-01

IND computer program introduces Bayesian and Markov/maximum-likelihood (MML) methods and more-sophisticated methods of searching in growing trees. Produces more-accurate class-probability estimates important in applications like diagnosis. Provides range of features and styles with convenience for casual user, fine-tuning for advanced user or for those interested in research. Consists of four basic kinds of routines: data-manipulation, tree-generation, tree-testing, and tree-display. Written in C language.

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

Science.gov (United States)

Eilmann, Britta; Rigling, Andreas

2012-02-01

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

Tree ring proxies show physiological responses of eastern red cedar to increased CO2 and SO4 concentrations over the 20th century

Science.gov (United States)

Thomas, R. B.; Spal, S.; Maxwell, S.; Nippert, J. B.

2011-12-01

We examined the relationships between tree growth during the past century and the ratio of internal carbon dioxide concentration to atmospheric CO2 concentration (ci/ca) and instantaneous water-use efficiency (iWUE) by analyzing δ13C in tree rings of Juniperus virginiana growing on a limestone outcrop in West Virginia, US. Tree rings from years 1909 to 2008 from five Juniperus virginiana trees that ranged from 116 years to over 300 years in age were measured for basal area growth and used for isotopic analysis. Instantaneous WUE increased from approximately 75 to 112μmol mmol-1 over the past century, representing a 49% increase. In addition, we found a positive relationship between iWUE and the basal area increase over this time period, suggesting the increase in WUE translated into greater growth of the Juniperus trees. Typically, we might expect that increased growth of these trees reflects increased photosynthetic rates and decreased stomatal conductance rates resulting from increased atmospheric CO2 concentrations. However, this area of the central Appalachian Mountains has historically received some of the highest rates of acid deposition in the nation resulting from being downwind from an abundance of coal-fired power plants in the Ohio River valley. Our results show that ci/ca declined 14% between 1909 and 1980, but increased 9.6% between 1980 and 2009. We hypothesize that the directional change in ci/ca that occurred around 1980 was due to a reduction in sulfur emissions imposed by the Clean Air Act, environmental legislation enacted in 1970 and amended in 1990. Sulfur deposition measured by the National Atmospheric Deposition Program (NADP) in West Virginia near our Juniperus site shows a 53% decline between 1979 and 2009 and these NADP data show a highly significant negative correlation with ci/ca of Juniperus over this time period. Previously, experimental studies have shown that acidic sulfur mist leaches calcium from leaves causing a reduction in

Are trees long-lived?

Science.gov (United States)

Kevin T. Smith

2009-01-01

Trees and tree care can capture the best of people's motivations and intentions. Trees are living memorials that help communities heal at sites of national tragedy, such as Oklahoma City and the World Trade Center. We mark the places of important historical events by the trees that grew nearby even if the original tree, such as the Charter Oak in Connecticut or...

A new subgenus of the weevil genus Otiorhynchus Germar, 1822 (Coleoptera: Curculionidae: Entiminae for a new species from Mediterranean Turkey associated with the carob tree, Ceratonia siliqua L. (Fabaceae

Directory of Open Access Journals (Sweden)

Genrik E. Davidian

2017-03-01

Full Text Available A new species Otiorhynchus ceratoniae Davidian, Gültekin & Korotyaev sp. nov. is described from eastern Mediterranean Turkey. A new monotypic subgenus Arnoldinus Davidian, Gültekin & Korotyaev subgen. nov. is erected for this species. The new species was found only under Ceratonia siliqua L. trees with lower leaves damaged by adults.

Evaluating the Use of Tree Shelters for Direct Seeding of Castanea on a Surface Mine in Appalachia

Directory of Open Access Journals (Sweden)

Christopher Barton

2015-10-01

Full Text Available American chestnut (Castanea dentata, once a primary constituent of the eastern hardwood forest ecosystem, was nearly extirpated from the forest canopy by the accidental introduction of chestnut blight (Cryphonectria parasitica. An intensive breeding program has sought to breed blight resistance from Chinese chestnut into American chestnuts, while maintaining as much of the desirable American chestnut phenotypes as possible. Previous studies suggest that these blight resistant American chestnuts, termed “restoration chestnuts”, are capable of thriving on reclaimed surface mines. We direct seeded pure Chinese, pure American, and three backcross lines into brown sandstone minesoil on a mine site in Pike County, KY. To investigate the effects of tree sheltering on survival and growth, we installed tree shelters on half the plots, and left the rest of the plots unsheltered. Results indicated that shelters were highly effective at reducing initial mortality. In addition, while pure Chinese chestnut survival was highest, the three backcross lines have also survived well on this site. Our study demonstrates that American, Chinese, and backcrossed chestnuts can survive through five growing seasons on reclaimed surface mines with the use of tree shelters.

Seasonal occurrence and impact of Halyomorpha halys (Hemiptera: Pentatomidae) in tree fruit.

Science.gov (United States)

Nielsen, Anne L; Hamilton, George C

2009-06-01

Halyomorpha halys is an introduced stink bug species from Asia that is spreading throughout the Mid-Atlantic United States. It is native to South Korea, Japan, and eastern China, where it is an occasional pest of tree fruit, including apple and pear. Cage experiments with adults placed on apple and peach during critical plant growth stages demonstrate that it can cause damage to developing fruit during mid- and late season growth periods and that feeding occurs on all regions of the fruit. Feeding that occurred during pit hardening/mid-season and final swell periods were apparent as damage at harvest, whereas feeding at shuck split/petal fall in peaches and apples caused fruit abscission. Tree fruit at two commercial farms were sampled weekly in 2006-2007 to determine H. halys seasonality. Low densities of nymphs in apple suggest that it is an unsuitable developmental host. Both nymphs and adults were found on pear fruits with peak populations occurring in early July and mid-August, the time when pit hardening/mid-season and swell period damage occurs. At both farms, stink bug damage was greater than 25% damaged fruit per tree. We attribute this to H. halys because population densities were significantly higher than native pentatomids at both locations in both beat samples and blacklight trap captures. The data presented here documents the potential for H. halys to cause damage in orchards throughout the Mid-Atlantic United States and shows the need for development of appropriate control strategies.

There's Life in Hazard Trees

Science.gov (United States)

Mary Torsello; Toni McLellan

The goals of hazard tree management programs are to maximize public safety and maintain a healthy sustainable tree resource. Although hazard tree management frequently targets removal of trees or parts of trees that attract wildlife, it can take into account a diversity of tree values. With just a little extra planning, hazard tree management can be highly beneficial...

Impacts of tree rows on grassland birds and potential nest predators: a removal experiment.

Science.gov (United States)

Ellison, Kevin S; Ribic, Christine A; Sample, David W; Fawcett, Megan J; Dadisman, John D

2013-01-01

Globally, grasslands and the wildlife that inhabit them are widely imperiled. Encroachment by shrubs and trees has widely impacted grasslands in the past 150 years. In North America, most grassland birds avoid nesting near woody vegetation. Because woody vegetation fragments grasslands and potential nest predator diversity and abundance is often greater along wooded edge and grassland transitions, we measured the impacts of removing rows of trees and shrubs that intersected grasslands on potential nest predators and the three most abundant grassland bird species (Henslow's sparrow [Ammodramus henslowii], Eastern meadowlark [Sturnella magna], and bobolink [Dolichonyx oryzivorus]) at sites in Wisconsin, U.S.A. We monitored 3 control and 3 treatment sites, for 1 yr prior to and 3 yr after tree row removal at the treatment sites. Grassland bird densities increased (2-4 times for bobolink and Henslow's sparrow) and nesting densities increased (all 3 species) in the removal areas compared to control areas. After removals, Henslow's sparrows nested within ≤50 m of the treatment area, where they did not occur when tree rows were present. Most dramatically, activity by woodland-associated predators nearly ceased (nine-fold decrease for raccoon [Procyon lotor]) at the removals and grassland predators increased (up to 27 times activity for thirteen-lined ground squirrel [Ictidomys tridecemlineatus]). Nest success did not increase, likely reflecting the increase in grassland predators. However, more nests were attempted by all 3 species (175 versus 116) and the number of successful nests for bobolinks and Henslow's sparrows increased. Because of gains in habitat, increased use by birds, greater production of young, and the effective removal of woodland-associated predators, tree row removal, where appropriate based on the predator community, can be a beneficial management action for conserving grassland birds and improving fragmented and degraded grassland ecosystems.

Impacts of tree rows on grassland birds and potential nest predators: a removal experiment.

Directory of Open Access Journals (Sweden)

Kevin S Ellison

Full Text Available Globally, grasslands and the wildlife that inhabit them are widely imperiled. Encroachment by shrubs and trees has widely impacted grasslands in the past 150 years. In North America, most grassland birds avoid nesting near woody vegetation. Because woody vegetation fragments grasslands and potential nest predator diversity and abundance is often greater along wooded edge and grassland transitions, we measured the impacts of removing rows of trees and shrubs that intersected grasslands on potential nest predators and the three most abundant grassland bird species (Henslow's sparrow [Ammodramus henslowii], Eastern meadowlark [Sturnella magna], and bobolink [Dolichonyx oryzivorus] at sites in Wisconsin, U.S.A. We monitored 3 control and 3 treatment sites, for 1 yr prior to and 3 yr after tree row removal at the treatment sites. Grassland bird densities increased (2-4 times for bobolink and Henslow's sparrow and nesting densities increased (all 3 species in the removal areas compared to control areas. After removals, Henslow's sparrows nested within ≤50 m of the treatment area, where they did not occur when tree rows were present. Most dramatically, activity by woodland-associated predators nearly ceased (nine-fold decrease for raccoon [Procyon lotor] at the removals and grassland predators increased (up to 27 times activity for thirteen-lined ground squirrel [Ictidomys tridecemlineatus]. Nest success did not increase, likely reflecting the increase in grassland predators. However, more nests were attempted by all 3 species (175 versus 116 and the number of successful nests for bobolinks and Henslow's sparrows increased. Because of gains in habitat, increased use by birds, greater production of young, and the effective removal of woodland-associated predators, tree row removal, where appropriate based on the predator community, can be a beneficial management action for conserving grassland birds and improving fragmented and degraded grassland

Fast Tree: Computing Large Minimum-Evolution Trees with Profiles instead of a Distance Matrix

Energy Technology Data Exchange (ETDEWEB)

N. Price, Morgan; S. Dehal, Paramvir; P. Arkin, Adam

2009-07-31

Gene families are growing rapidly, but standard methods for inferring phylogenies do not scale to alignments with over 10,000 sequences. We present FastTree, a method for constructing large phylogenies and for estimating their reliability. Instead of storing a distance matrix, FastTree stores sequence profiles of internal nodes in the tree. FastTree uses these profiles to implement neighbor-joining and uses heuristics to quickly identify candidate joins. FastTree then uses nearest-neighbor interchanges to reduce the length of the tree. For an alignment with N sequences, L sites, and a different characters, a distance matrix requires O(N^2) space and O(N^2 L) time, but FastTree requires just O( NLa + N sqrt(N) ) memory and O( N sqrt(N) log(N) L a ) time. To estimate the tree's reliability, FastTree uses local bootstrapping, which gives another 100-fold speedup over a distance matrix. For example, FastTree computed a tree and support values for 158,022 distinct 16S ribosomal RNAs in 17 hours and 2.4 gigabytes of memory. Just computing pairwise Jukes-Cantor distances and storing them, without inferring a tree or bootstrapping, would require 17 hours and 50 gigabytes of memory. In simulations, FastTree was slightly more accurate than neighbor joining, BIONJ, or FastME; on genuine alignments, FastTree's topologies had higher likelihoods. FastTree is available at http://microbesonline.org/fasttree.

TreeRipper web application: towards a fully automated optical tree recognition software

Directory of Open Access Journals (Sweden)

Hughes Joseph

2011-05-01

Full Text Available Abstract Background Relationships between species, genes and genomes have been printed as trees for over a century. Whilst this may have been the best format for exchanging and sharing phylogenetic hypotheses during the 20th century, the worldwide web now provides faster and automated ways of transferring and sharing phylogenetic knowledge. However, novel software is needed to defrost these published phylogenies for the 21st century. Results TreeRipper is a simple website for the fully-automated recognition of multifurcating phylogenetic trees (http://linnaeus.zoology.gla.ac.uk/~jhughes/treeripper/. The program accepts a range of input image formats (PNG, JPG/JPEG or GIF. The underlying command line c++ program follows a number of cleaning steps to detect lines, remove node labels, patch-up broken lines and corners and detect line edges. The edge contour is then determined to detect the branch length, tip label positions and the topology of the tree. Optical Character Recognition (OCR is used to convert the tip labels into text with the freely available tesseract-ocr software. 32% of images meeting the prerequisites for TreeRipper were successfully recognised, the largest tree had 115 leaves. Conclusions Despite the diversity of ways phylogenies have been illustrated making the design of a fully automated tree recognition software difficult, TreeRipper is a step towards automating the digitization of past phylogenies. We also provide a dataset of 100 tree images and associated tree files for training and/or benchmarking future software. TreeRipper is an open source project licensed under the GNU General Public Licence v3.

MixtureTree annotator: a program for automatic colorization and visual annotation of MixtureTree.

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Shu-Chuan Chen

Full Text Available The MixtureTree Annotator, written in JAVA, allows the user to automatically color any phylogenetic tree in Newick format generated from any phylogeny reconstruction program and output the Nexus file. By providing the ability to automatically color the tree by sequence name, the MixtureTree Annotator provides a unique advantage over any other programs which perform a similar function. In addition, the MixtureTree Annotator is the only package that can efficiently annotate the output produced by MixtureTree with mutation information and coalescent time information. In order to visualize the resulting output file, a modified version of FigTree is used. Certain popular methods, which lack good built-in visualization tools, for example, MEGA, Mesquite, PHY-FI, TreeView, treeGraph and Geneious, may give results with human errors due to either manually adding colors to each node or with other limitations, for example only using color based on a number, such as branch length, or by taxonomy. In addition to allowing the user to automatically color any given Newick tree by sequence name, the MixtureTree Annotator is the only method that allows the user to automatically annotate the resulting tree created by the MixtureTree program. The MixtureTree Annotator is fast and easy-to-use, while still allowing the user full control over the coloring and annotating process.

On Determining if Tree-based Networks Contain Fixed Trees.

Science.gov (United States)

Anaya, Maria; Anipchenko-Ulaj, Olga; Ashfaq, Aisha; Chiu, Joyce; Kaiser, Mahedi; Ohsawa, Max Shoji; Owen, Megan; Pavlechko, Ella; St John, Katherine; Suleria, Shivam; Thompson, Keith; Yap, Corrine

2016-05-01

We address an open question of Francis and Steel about phylogenetic networks and trees. They give a polynomial time algorithm to decide if a phylogenetic network, N, is tree-based and pose the problem: given a fixed tree T and network N, is N based on T? We show that it is [Formula: see text]-hard to decide, by reduction from 3-Dimensional Matching (3DM) and further that the problem is fixed-parameter tractable.

Whole-tree distribution and temporal variation of non-structural carbohydrates in broadleaf evergreen trees.

Science.gov (United States)

Smith, Merryn G; Miller, Rebecca E; Arndt, Stefan K; Kasel, Sabine; Bennett, Lauren T

2018-04-01

Non-structural carbohydrates (NSCs) form a fundamental yet poorly quantified carbon pool in trees. Studies of NSC seasonality in forest trees have seldom measured whole-tree NSC stocks and allocation among organs, and are not representative of all tree functional types. Non-structural carbohydrate research has primarily focussed on broadleaf deciduous and coniferous evergreen trees with distinct growing seasons, while broadleaf evergreen trees remain under-studied despite their different growth phenology. We measured whole-tree NSC allocation and temporal variation in Eucalyptus obliqua L'Hér., a broadleaf evergreen tree species typically occurring in mixed-age temperate forests, which has year-round growth and the capacity to resprout after fire. Our overarching objective was to improve the empirical basis for understanding the functional importance of NSC allocation and stock changes at the tree- and organ-level in this tree functional type. Starch was the principal storage carbohydrate and was primarily stored in the stem and roots of young (14-year-old) trees rather than the lignotuber, which did not appear to be a specialized starch storage organ. Whole-tree NSC stocks were depleted during spring and summer due to significant decreases in starch mass in the roots and stem, seemingly to support root and crown growth but potentially exacerbated by water stress in summer. Seasonality of stem NSCs differed between young and mature trees, and was not synchronized with stem basal area increments in mature trees. Our results suggest that the relative magnitude of seasonal NSC stock changes could vary with tree growth stage, and that the main drivers of NSC fluctuations in broadleaf evergreen trees in temperate biomes could be periodic disturbances such as summer drought and fire, rather than growth phenology. These results have implications for understanding post-fire tree recovery via resprouting, and for incorporating NSC pools into carbon models of mixed

The effect of contaminated groundwater on tree growth: A tree-ring analysis

International Nuclear Information System (INIS)

LeBlanc, D.C.; Loehle, C.

1990-10-01

A study was conducted on the effect of contaminated groundwater seepage on tree growth downslope from F- and H-Area seepage basins of the Savannah River Site. Trees in wetlands along Four Mile Creek began to show localized stress and mortality in the late 1970s. Extreme winter temperatures and high rainfall were ruled out as potential causal factors of tree stress. Drought was shown to affect trees in both contaminated and uncontaminated zones, but trees in uncontaminated areas exhibit better recovery after drought than trees in contaminated areas. Pollution-mediated alteration of soil acidity and aluminum, sodium, and heavy metal concentrations likely acted to predispose trees to decline, with severe drought acting as the trigger for decline initiation and tree death. Thus, a moderate pollution loading, not sufficient to cause visible damage of itself, may create conditions in which sudden, severe decline could result from natural stresses. This mechanism of forest decline is common, and should be considered in evaluations of the impact of pollution on wetland forest systems. 28 refs., 4 figs., 6 tabs

SILVA tree viewer: interactive web browsing of the SILVA phylogenetic guide trees.

Science.gov (United States)

Beccati, Alan; Gerken, Jan; Quast, Christian; Yilmaz, Pelin; Glöckner, Frank Oliver

2017-09-30

Phylogenetic trees are an important tool to study the evolutionary relationships among organisms. The huge amount of available taxa poses difficulties in their interactive visualization. This hampers the interaction with the users to provide feedback for the further improvement of the taxonomic framework. The SILVA Tree Viewer is a web application designed for visualizing large phylogenetic trees without requiring the download of any software tool or data files. The SILVA Tree Viewer is based on Web Geographic Information Systems (Web-GIS) technology with a PostgreSQL backend. It enables zoom and pan functionalities similar to Google Maps. The SILVA Tree Viewer enables access to two phylogenetic (guide) trees provided by the SILVA database: the SSU Ref NR99 inferred from high-quality, full-length small subunit sequences, clustered at 99% sequence identity and the LSU Ref inferred from high-quality, full-length large subunit sequences. The Tree Viewer provides tree navigation, search and browse tools as well as an interactive feedback system to collect any kinds of requests ranging from taxonomy to data curation and improving the tool itself.

Interspecific differences and commonalities in maternity roosting by tree cavity-roosting bats over a maternity season in a timber production landscape

Science.gov (United States)

Law, Brad; Goldingay, Ross

2018-01-01

Understanding maternity roost requirements is fundamental to guide timber production forest management given such roosts are vital to sustain bat populations. We tracked lactating females of three tree cavity-roosting species: Gould's long-eared bat (Nyctophilus gouldi) (n = 7), eastern broad-nosed bat (Scotorepens orion) (n = 6) and little forest bat (Vespadelus vulturnus) (n = 25), over five weeks in young (predominately trees were located. Bats displayed a degree of maternity roost selection plasticity, however, interspecific differences were found. Nyctophilus gouldi roosted selectively in retained riparian buffers, in trees of high senescence and switched roosts every day. Vespadelus vulturnus roosted in logged areas and displayed high roost site fidelity, with one roost used for 33 consecutive days. Scotorepens orion selected large live trees of low senescence. The preliminary data for this species suggests that females roost most days in ‘primary’ roosts but display a roost switching behaviour conforming to the fission-fusion model. Dead trees were identified to be important for both N. gouldi and V. vulturnus. Historical and recent logging at our study area drastically reduced cavity-bearing tree density to 1.4 trees per hectare in the logging zones (outside of exclusion areas), potentially limiting local populations of tree cavity-roosting bats and other cavity-dependent wildlife. Our data demonstrate that forest management must consider a range of maternity roost requirements to accommodate differences among species and highlight the importance of exclusion areas for roost habitat. We propose that an expanded ‘retention forestry’ approach should be implemented in logged areas that includes in-perpetuity forest patch retention to increase habitat complexity and continuity. PMID:29543883

Geology of Joshua Tree National Park geodatabase

Science.gov (United States)

Powell, Robert E.; Matti, Jonathan C.; Cossette, Pamela M.

2015-09-16

The database in this Open-File Report describes the geology of Joshua Tree National Park and was completed in support of the National Cooperative Geologic Mapping Program of the U.S. Geological Survey (USGS) and in cooperation with the National Park Service (NPS). The geologic observations and interpretations represented in the database are relevant to both the ongoing scientific interests of the USGS in southern California and the management requirements of NPS, specifically of Joshua Tree National Park (JOTR).Joshua Tree National Park is situated within the eastern part of California’s Transverse Ranges province and straddles the transition between the Mojave and Sonoran deserts. The geologically diverse terrain that underlies JOTR reveals a rich and varied geologic evolution, one that spans nearly two billion years of Earth history. The Park’s landscape is the current expression of this evolution, its varied landforms reflecting the differing origins of underlying rock types and their differing responses to subsequent geologic events. Crystalline basement in the Park consists of Proterozoic plutonic and metamorphic rocks intruded by a composite Mesozoic batholith of Triassic through Late Cretaceous plutons arrayed in northwest-trending lithodemic belts. The basement was exhumed during the Cenozoic and underwent differential deep weathering beneath a low-relief erosion surface, with the deepest weathering profiles forming on quartz-rich, biotite-bearing granitoid rocks. Disruption of the basement terrain by faults of the San Andreas system began ca. 20 Ma and the JOTR sinistral domain, preceded by basalt eruptions, began perhaps as early as ca. 7 Ma, but no later than 5 Ma. Uplift of the mountain blocks during this interval led to erosional stripping of the thick zones of weathered quartz-rich granitoid rocks to form etchplains dotted by bouldery tors—the iconic landscape of the Park. The stripped debris filled basins along the fault zones.Mountain ranges

Growth responses of trees and understory plants to nitrogen fertilization in a subtropical forest in China

Science.gov (United States)

Tian, Di; Li, Peng; Fang, Wenjing; Xu, Jun; Luo, Yongkai; Yan, Zhengbing; Zhu, Biao; Wang, Jingjing; Xu, Xiaoniu; Fang, Jingyun

2017-07-01

Reactive nitrogen (N) increase in the biosphere has been a noteworthy aspect of global change, producing considerable ecological effects on the functioning and dynamics of the terrestrial ecosystems. A number of observational studies have explored responses of plants to experimentally simulated N enrichment in boreal and temperate forests. Here we investigate how the dominant trees and different understory plants respond to experimental N enrichment in a subtropical forest in China. We conducted a 3.4-year N fertilization experiment in an old-aged subtropical evergreen broad-leaved forest in eastern China with three treatment levels applied to nine 20 m × 20 m plots and replicated in three blocks. We divided the plants into trees, saplings, shrubs (including tree seedlings), and ground-cover plants (ferns) according to the growth forms, and then measured the absolute and relative basal area increments of trees and saplings and the aboveground biomass of understory shrubs and ferns. We further grouped individuals of the dominant tree species, Castanopsis eyrei, into three size classes to investigate their respective growth responses to the N fertilization. Our results showed that the plot-averaged absolute and relative growth rates of basal area and aboveground biomass of trees were not affected by N fertilization. Across the individuals of C. eyrei, the small trees with a DBH (diameter at breast height) of 5-10 cm declined by 66.4 and 59.5 %, respectively, in N50 (50 kg N ha-1 yr-1) and N100 fertilized plots (100 kg N ha-1 yr-1), while the growth of median and large trees with a DBH of > 10 cm did not significantly change with the N fertilization. The growth rate of small trees, saplings, and the aboveground biomass of understory shrubs and ground-cover ferns decreased significantly in the N-fertilized plots. Our findings suggested that N might not be a limiting nutrient in this mature subtropical forest, and that the limitation of other nutrients in the forest

Growth responses of trees and understory plants to nitrogen fertilization in a subtropical forest in China

Directory of Open Access Journals (Sweden)

D. Tian

2017-07-01

Full Text Available Reactive nitrogen (N increase in the biosphere has been a noteworthy aspect of global change, producing considerable ecological effects on the functioning and dynamics of the terrestrial ecosystems. A number of observational studies have explored responses of plants to experimentally simulated N enrichment in boreal and temperate forests. Here we investigate how the dominant trees and different understory plants respond to experimental N enrichment in a subtropical forest in China. We conducted a 3.4-year N fertilization experiment in an old-aged subtropical evergreen broad-leaved forest in eastern China with three treatment levels applied to nine 20 m  ×  20 m plots and replicated in three blocks. We divided the plants into trees, saplings, shrubs (including tree seedlings, and ground-cover plants (ferns according to the growth forms, and then measured the absolute and relative basal area increments of trees and saplings and the aboveground biomass of understory shrubs and ferns. We further grouped individuals of the dominant tree species, Castanopsis eyrei, into three size classes to investigate their respective growth responses to the N fertilization. Our results showed that the plot-averaged absolute and relative growth rates of basal area and aboveground biomass of trees were not affected by N fertilization. Across the individuals of C. eyrei, the small trees with a DBH (diameter at breast height of 5–10 cm declined by 66.4 and 59.5 %, respectively, in N50 (50 kg N ha−1 yr−1 and N100 fertilized plots (100 kg N ha−1 yr−1, while the growth of median and large trees with a DBH of  >  10 cm did not significantly change with the N fertilization. The growth rate of small trees, saplings, and the aboveground biomass of understory shrubs and ground-cover ferns decreased significantly in the N-fertilized plots. Our findings suggested that N might not be a limiting nutrient in this mature subtropical

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...

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

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.

Identifying the rooted species tree from the distribution of unrooted gene trees under the coalescent.

Science.gov (United States)

Allman, Elizabeth S; Degnan, James H; Rhodes, John A

2011-06-01

Gene trees are evolutionary trees representing the ancestry of genes sampled from multiple populations. Species trees represent populations of individuals-each with many genes-splitting into new populations or species. The coalescent process, which models ancestry of gene copies within populations, is often used to model the probability distribution of gene trees given a fixed species tree. This multispecies coalescent model provides a framework for phylogeneticists to infer species trees from gene trees using maximum likelihood or Bayesian approaches. Because the coalescent models a branching process over time, all trees are typically assumed to be rooted in this setting. Often, however, gene trees inferred by traditional phylogenetic methods are unrooted. We investigate probabilities of unrooted gene trees under the multispecies coalescent model. We show that when there are four species with one gene sampled per species, the distribution of unrooted gene tree topologies identifies the unrooted species tree topology and some, but not all, information in the species tree edges (branch lengths). The location of the root on the species tree is not identifiable in this situation. However, for 5 or more species with one gene sampled per species, we show that the distribution of unrooted gene tree topologies identifies the rooted species tree topology and all its internal branch lengths. The length of any pendant branch leading to a leaf of the species tree is also identifiable for any species from which more than one gene is sampled.

[Aboveground biomass and nutrient distribution patterns of larch plantation in a montane region of eastern Liaoning Province, China].

Science.gov (United States)

Yan, Tao; Zhu, Jiao-Jun; Yang, Kai; Yu, Li-Zhong

2014-10-01

Larch is the main timber species of forest plantations in North China. Imbalance in nutrient cycling in soil emerged due to single species composition and mono system structure of plantation. Thus it is necessary to grasp its biomass and nutrients allocation for scientific management and nutrient cycling studies of larch plantation. We measured aboveground biomass (stem, branch, bark and leaf) and nutrient concentrations (C, N, P, K, Ca, Mg, Fe, Mn, Cu and Zn), and analyzed the patterns of accumulation and distribution of 19-year-old larch plantation with diameter at breast height of 12. 8 cm, tree height of 15. 3 m, and density of 2308 trees · hm(-2), in a montane region of eastern Liaoning Province, China. The results showed that aboveground biomass values were 70.26 kg and 162.16 t · hm(-2) for the individual tree of larch and the stand, respectively. There was a significant difference between biomass of the organs, and decreased in the order of stem > branch > bark > leaf. Nutrient accumulation was 749.94 g and 1730.86 kg · hm(-2) for the individual tree of larch and the stand, respectively. Nutrient accumulation of stem was significantly higher than that of branch, bark and leaf, whether it was macro-nutrient or micro-nutrient. Averagely, 749.94 g nutrient elements would be removed from the system when a 19-year-old larch tree was harvested. If only the stem part was removed from the system, the removal of nutrient elements could be reduced by 40.7%.

IAEA/WHO postal dose audits for radiotherapy hospitals in Eastern and South-Eastern Europe

International Nuclear Information System (INIS)

Izewska, J.; Vatnitsky, S.; Shortt, K.R.

2004-01-01

The IAEA/WHO TLD programme has been in operation for 34 years. In this period the calibration of approximately 5200 high-energy photon beams in over 1300 radiotherapy hospitals in 115 countries worldwide was checked. Of these, 18% of the audits were performed in Eastern and South-Eastern Europe. There are large contrasts in the region; while the results are very good for most countries, a few countries struggle with basic problems in dosimetry. The hospitals operating radiotherapy services without qualified medical physicists or dosimetry equipment have poorer results than those properly equipped and staffed. Only about 2/3 of TLD audit participants in Eastern Europe have the appropriate dosimetry equipment. To achieve consistency of the audit results within Eastern and South-Eastern Europe, strengthening of radiotherapy infrastructure in a few countries would be necessary. (authors)

Seismic hazard assessment of the Hanford region, Eastern Washington State

International Nuclear Information System (INIS)

Youngs, R.R.; Coppersmith, K.J.; Power, M.S.; Swan, F.H. III

1985-01-01

A probabilistic seismic hazard assessment was made for a site within the Hanford region of eastern Washington state, which is characterized as an intraplate region having a relatively low rate of seismic activity. Probabilistic procedures, such as logic trees, were utilized to account for the uncertainties in identifying and characterizing the potential seismic sources in the region. Logic trees provide a convenient, flexible means of assessing the values and relative likelihoods of input parameters to the hazard model that may be dependent upon each other. Uncertainties accounted for in this way include the tectonic model, segmentation, capability, fault geometry, maximum earthquake magnitude, and earthquake recurrence rate. The computed hazard results are expressed as a distribution from which confidence levels are assessed. Analysis of the results show the contributions to the total hazard from various seismic sources and due to various earthquake magnitudes. In addition, the contributions of uncertainties in the various source parameters to the uncertainty in the computed hazard are assessed. For this study, the major contribution to uncertainty in the computed hazard are due to uncertainties in the applicable tectonic model and the earthquake recurrence rate. This analysis serves to illustrate some of the probabilistic tools that are available for conducting seismic hazard assessments and for analyzing the results of these studies. 5 references, 7 figures

75 FR 68397 - DeQueen and Eastern Railroad, LLC-Acquisition and Operation Exemption-DeQueen and Eastern...

Science.gov (United States)

2010-11-05

... Eastern Railroad, LLC--Acquisition and Operation Exemption--DeQueen and Eastern Railroad Company DeQueen and Eastern Railroad, LLC (DQE), a noncarrier, has filed a verified notice of exemption under 49 CFR 1150.31 to acquire from DeQueen and Eastern Railroad Company and to operate approximately 47 miles of...

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...... tree is isomorphic to T? We prove that in the general setting, CST is NP-complete, which implies that the tree edit distance considered here is also NP-hard, even when both input trees having diameters bounded by 10. We also show that, when the number of distinct stars is bounded by a constant k, CTS...

Area Studies and Eastern Europe: How Eastern Europe Collapsed

Directory of Open Access Journals (Sweden)

Mirjana Kasapović

2007-01-01

Full Text Available In the first part, the author outlines the development of area studies in contemporary comparative politics, and points to their importance for the development of political science. In the second part, she examines the methodology – research design and methods – of regional comparatistics, paying particular attention to the problem of defining the region as a central category in this field of comparative politics. The third and central part is focused on the emergence of Eastern Europe as a historical-political and socio-cultural region in the course of history, especially after World War II, and on its dissolution in the processes of democratic transformation of communist regimes in the last two decades. The dissolution of Eastern Europe has resulted in restoration of a tripartite political geography in the area which it used to take up, made up of Central Europe, Southeast Europe and the proper Eastern Europe.

Long-term forest dynamics at Gribskov, eastern Denmark with early-Holocene evidence for thermophilous broadleaved tree species

DEFF Research Database (Denmark)

Overballe-Petersen, Mette V; Nielsen, Anne Birgitte; Hannon, Gina E.

2012-01-01

two periods of the early Holocene and from c. 3000 cal. BP to present. The early-Holocene part of the record indicates a highly disturbed forest ecosystem with frequent fires and abundant macrofossils of particularly Betula sp. and Populus sp. The sediment stratigraphy and age–depth relationships give......We report on a full-Holocene pollen, charcoal and macrofossil record from a small forest hollow in Gribskov, eastern Denmark. The Fagus sylvatica pollen record suggests the establishment of a small Fagus population at Gribskov in the early Holocene together with early establishment of other...

Trees in the city: valuing street trees in Portland, Oregon

Science.gov (United States)

G.H. Donovan; D.T. Butry

2010-01-01

We use a hedonic price model to simultaneously estimate the effects of street trees on the sales price and the time-on-market (TOM) of houses in Portland. Oregon. On average, street trees add $8,870 to sales price and reduce TOM by 1.7 days. In addition, we found that the benefits of street trees spill over to neighboring houses. Because the provision and maintenance...

Effects of rhododendron removal on the water use of hardwood species following eastern hemlock mortality

Science.gov (United States)

Hawthorne, S. N.; Miniat, C.; Elliott, K.

2017-12-01

Forest disturbance that alters vegetation species composition can affect ecosystem productivity and function. The loss of eastern hemlock (Tsuga canadensis) to hemlock woolly adelgid infestations in southern Appalachian Mountains has resulted in more than a two-fold increase in growth of co-occurring rhododendron (Rhododendron maximum) understory, evergreen shrubs. In contrast, the growth of hardwood species increased by 1.2 fold during the same 5 year period following infestation. This study examines the effects of mechanically removing the rhododendron shrub layer on water use and growth of hardwood species. The treatment—hypothesized to speed ecosystem recovery of structure and function—involved cutting, spreading and burning rhododendron stems to remove both rhododendron and soil O-horizon. Sap flow, soil moisture and micro-climate (humidity, temperature) were measured in a pair of reference and treated plots. Preliminary results from the relatively dry summer/fall 2016 have shown that the mean daily transpiration (Et) of the treated plot was 24% greater than the mean daily Et of hardwood trees in the reference plot (t-test, p treatment plots compared to the reference plots. This suggests that the removal of the shrub layer reduced competition for resources for the canopy and seedling trees, which may increase tree growth and recruitment. Thus, in the wake of hemlock loss, recovery of riparian forest structure and function may be aided with shrub layer removal.

Urban tree growth modeling

Science.gov (United States)

E. Gregory McPherson; Paula J. Peper

2012-01-01

This paper describes three long-term tree growth studies conducted to evaluate tree performance because repeated measurements of the same trees produce critical data for growth model calibration and validation. Several empirical and process-based approaches to modeling tree growth are reviewed. Modeling is more advanced in the fields of forestry and...

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....

Performance of The Selected Main Tree of Liberoid Coffe in The Peatland of Meranti Island, Riau

Directory of Open Access Journals (Sweden)

Budi Martono

2017-01-01

Full Text Available In order to develop (renewal and extension the Liberoid coffee in peatland, it is necessary to do the program of increasing production and quality of Liberoid coffee. It requires the superior planting materials of superior in specific location. This study has the objective to find out the performance of the selected main trees of Liberoid coffee. The study was conducted from January to September 2015 in the area of peatland in the Kedaburapat village, Rangsang Pesisir District, Kepulauan Meranti Regency, Riau. The method used was the direct observation of main trees of selected Liberoid coffee. The observed character is quantitative and qualitative character. The results showed the diversity of quantitative characters within a range between 7.39 to 40.11%. The average number of pieces / bunch is third with a production of 30.63 kg / tree / year, 288.25 cm plant height, stem diameter 36.88 cm, the number of primary branches of 5.88; the number of secondary branches 12.63, crown width 185.88 cm western, eastern 201.13 cm, 209.25 cm southern and northern 216.75 cm. The diversity of qualitative character is seen in the character of shoot color, old fruit color, fruit shape, fruit discuss, and the upper surface of the leaf.

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.

Seed production differences of the Andean oak Quercus Humboldtii Bonpl. in two Andean forests of the Colombian Eastern Cordillera

International Nuclear Information System (INIS)

Gonzalez Melo, Andres; Parrado Rosselli Angela

2010-01-01

Knowledge of mechanisms of tree species reproduction under natural situations including fruit and seed production patterns is very important for forest management strategies. Considering the influence of abiotic factors such as soil characteristics, humidity and rainfall on fruiting phenology, we studied fruit production patterns of the Andean oak (Quercus humboldtii: Fagaceae) in two forest sites of the Colombian Eastern Cordillera (Cachalu and Patios Altos), under contrasting environmental conditions. At both sites, we monitored monthly fruit production of 15 trees in Cachalu and 11 in Patios Altos using fruit/seed traps placed under the tree crowns. In each site soil cores were extracted below the litter layer 20 cm depth, and soil characteristics and nutrients were analyzed. In general, trees in Cachalu produced more fruits than in Patios Altos, as well as mean fruit mass (wet and dry weight) was significantly higher in Cachalu. At both sites, oak fruiting peaked from April to May, when the highest rainfall occurs. We found positive correlations between fruit production and rainfall one month prior. High phosphorus (P) and potassium (K) were the main variables for explaining the high production. In contrast, high aluminum (Al) contents explained the low production found in Patios Altos. We discuss the importance of including fruit production for oak management strategies, such as restoration and reforestation programs.

Population Spatial Dynamics of Larix potaninii in Alpine Treeline Ecotone in the Eastern Margin of the Tibetan Plateau, China

Directory of Open Access Journals (Sweden)

Jia’nan Cui

2017-09-01

Full Text Available The high-altitude treeline is known to be sensitive to climate variability, and is thus considered as a bio-monitoring indicator of climate change. However, our understanding of the population dynamics and the cumulative climate-change effects on the alpine treeline ecotone in recent decades is limited. Here, we investigated the population dynamics of Larix potainii on the south- and north-facing slopes in the alpine treeline ecotone in the eastern margin of the Tibetan Plateau, China, including treeline position, population density, and tree recruitment. Results showed that on both south- and north-facing slopes, the treeline did not show a significant advancement in the past four decades. The population was dominated by young individuals, which tend to be established in the lower areas. Larix, here, tends to be clustered, especially in the upper areas. However, population density increased dramatically only on north-facing slopes. Larix here suffer from the stressful environment, but the warmer winter due to climate warming could facilitate the vertical growth of seedlings and saplings. Aggregated spatial patterns also provide a positive feedback in ameliorating the harsh environment. The slope-climate-moisture interactions have a pronounced impact on tree recruitment, including snow-limited tree establishment on the north-facing slopes and moisture-limited tree establishment on the south-facing slopes.

FB-Tree: A B+-Tree for Flash-Based SSDs

DEFF Research Database (Denmark)

Jørgensen, Martin V.; Rasmussen, René B.; Saltenis, Simonas

2011-01-01

Due to their many advantages, flash-based SSDs (Solid-State Drives) have become a mainstream alternative to magnetic disks for database servers. Nevertheless, database systems, designed and optimized for magnetic disks, still do not fully exploit all the benefits of the new technology. We propose....... As a consequence, the FB-tree outperforms a regular B+-tree in all scenarios tested. For instance, the throughput of a random workload of 75% updates increases by a factor of three using only two times the space of the B+-tree....

Benefit-based tree valuation

Science.gov (United States)

E.G. McPherson

2007-01-01

Benefit-based tree valuation provides alternative estimates of the fair and reasonable value of trees while illustrating the relative contribution of different benefit types. This study compared estimates of tree value obtained using cost- and benefit-based approaches. The cost-based approach used the Council of Landscape and Tree Appraisers trunk formula method, and...

Fragmentation of random trees

International Nuclear Information System (INIS)

Kalay, Z; Ben-Naim, E

2015-01-01

We study fragmentation of a random recursive tree into a forest by repeated removal of nodes. The initial tree consists of N nodes and it is generated by sequential addition of nodes with each new node attaching to a randomly-selected existing node. As nodes are removed from the tree, one at a time, the tree dissolves into an ensemble of separate trees, namely, a forest. We study statistical properties of trees and nodes in this heterogeneous forest, and find that the fraction of remaining nodes m characterizes the system in the limit N→∞. We obtain analytically the size density ϕ s of trees of size s. The size density has power-law tail ϕ s ∼s −α with exponent α=1+(1/m). Therefore, the tail becomes steeper as further nodes are removed, and the fragmentation process is unusual in that exponent α increases continuously with time. We also extend our analysis to the case where nodes are added as well as removed, and obtain the asymptotic size density for growing trees. (paper)

FTAP, Minimal Cut Sets of Arbitrary Fault Trees. FRTPLT, Fault Tree Structure and Logical Gates Plot for Program FTAP. FRTGEN, Fault Trees by Sub-tree Generator from Parent Tree for Program FTAP

International Nuclear Information System (INIS)

Willie, Randall R.; Rabien, U.

1997-01-01

1 - Description of problem or function: FTAP is a general-purpose program for deriving minimal reliability cut and path set families from the fault tree for a complex system. The program has a number of useful features that make it well-suited to nearly all fault tree applications. An input fault tree may specify the system state as any logical function of subsystem or component state variables or complements of these variables; thus, for instance, 'exclusive-or' type relations may be formed. When fault tree logical relations involve complements of state variables, the analyst may instruct FTAP to produce a family of prime implicants, a generalization of the minimal cut set concept. The program offers the flexibility of several distinct methods of generating cut set families. FTAP can also identify certain subsystems as system modules and provide a collection of minimal cut set families that essentially expresses the system state as a function of these module state variables. Another feature allows a useful subfamily to be obtained when the family of minimal cut sets or prime implicants is too large to be found in its entirety; this subfamily may consist of only those sets not containing more than some fixed number of elements or only those sets 'interesting' to the analyst in some special sense. Finally, the analyst can modify the input fault tree in various ways by declaring state variables identically true or false. 2 - Method of solution: Fault tree methods are based on the observation that the system state, either working or failed, can usually be expressed as a Boolean relation between states of several large, readily identifiable subsystems. The state of each subsystem in turn depends on states of simpler subsystems and components which compose it, so that the state of the system itself is determined by a hierarchy of logical relationships between states of subsystems. A fault tree is a graphical representation of these relationships. 3 - Restrictions on the

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…

36 CFR 223.4 - Exchange of trees or portions of trees.

Science.gov (United States)

2010-07-01

... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Exchange of trees or portions of trees. 223.4 Section 223.4 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER General Provisions § 223.4 Exchange of trees or...

How many trees are enough? Tree death and the urban canopy

Science.gov (United States)

Lara A. Roman

2014-01-01

Massive city tree planting campaigns have invigorated the urban forestry movement, and engaged politicians, planners, and the public in urban greening. Million tree initiatives have been launched in Los Angeles, CA; Denver, CO; New York City, NY; Philadelphia, PA, and other cities. Sacramento, CA even has a five million tree program. These...

Keeping trees as assets

Science.gov (United States)

Kevin T. Smith

2009-01-01

Landscape trees have real value and contribute to making livable communities. Making the most of that value requires providing trees with the proper care and attention. As potentially large and long-lived organisms, trees benefit from commitment to regular care that respects the natural tree system. This system captures, transforms, and uses energy to survive, grow,...

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...

Forest FIRE and FIRE wood : tools for tree automata and tree algorithms

NARCIS (Netherlands)

Cleophas, L.G.W.A.; Piskorski, J.; Watson, B.W.; Yli-Jyrä, A.

2009-01-01

Pattern matching, acceptance, and parsing algorithms on node-labeled, ordered, ranked trees ('tree algorithms') are important for applications such as instruction selection and tree transformation/term rewriting. Many such algorithms have been developed. They often are based on results from such

Can tree-ring isotopes (δ18O and δ13C) improve our understanding of hydroclimate variability in the Columbia River Basin?

Science.gov (United States)

Csank, A. Z.; Wise, E.; McAfee, S. A.

2015-12-01

The trajectory of incoming storms from the Pacific Ocean has a strong impact on hydroclimate in the Pacific Northwest. Shifts between zonal and meridional flow are a key influence on drought and pluvial regimes in both the PNW and the western United States as a whole. Circulation-dependent variability in the isotopic composition of precipitation can be recorded and potentially reconstructed using δ18O records derived from tree-rings. Here we present isotopic records of δ18O and δ13C from ponderosa pine (Pinus ponderosa) for the period 1950-2013 from six sites located in the lee of the Cascades in eastern Washington. Because of the orientation of the Cascades, zonal flow will result in an intensified rain shadow whereas meridional flow allows moisture to penetrate at a lower elevation leading to a lower rainout effect. This means zonal flow results in drier conditions in eastern Washington and the converse for meridional flow. We hypothesized that more depleted precipitation δ18O values will occur with periods of more zonal flow across the PNW and will be recorded by trees at our sites. Results show a strong relationship between our δ18O chronologies and winter precipitation (R = -0.50; p<0.001). δ13C chronologies from the same trees showed a relationship to prior fall/winter (pOct-pDec) precipitation (R = -0.46; p<0.005) suggesting a possible link to antecedent moisture conditions. With a focus on years with clear zonal and meridional flow regimes, we regressed the tree-ring δ18O anomaly against the instrumental record of total precipitation and compared the residual series to records of storm track for the period 1978-2008, and we found a detectable signal where the most depleted δ18O was generally associated with zonal flow and the most enriched δ18O with meridional flow. However, there are still some years where the relationship is unclear. Further work is aimed at understanding these anomalous years and extending our record beyond the instrumental

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

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.

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

Directory of Open Access Journals (Sweden)

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.

Spatiotemporal drought variability of the eastern Tibetan Plateau during the last millennium

Science.gov (United States)

Deng, Yang; Gou, Xiaohua; Gao, Linlin; Yang, Meixue; Zhang, Fen

2017-09-01

Tibetan Plateau is the headwater region of many major Asian rivers and very susceptive to climate change. Therefore, knowledge about climate and its spatiotemporal variability in this area is very important for ecological conservation, water resource management and social development. The aim of this study was to reconstruct and analyze the hydroclimate variation on eastern Tibetan Plateau (ETP) over many centuries and explore possible forcing factors on regional hydroclimate variability. We used 118 tree-ring chronologies from ETP to reconstruct the gridded May-July Standardized Precipitation Evapotranspiration Index for the ETP over the last millennium. The reconstruction was developed using an ensemble point-by-point reconstruction method, and a searching region method was used to locate the candidate tree-ring chronologies. The reconstructions have nicely captured the spatial and temporal features of the regional drought variation. The drought variations in south and north of 32.5°N are notably different, which may be related to the divergence influence of North Atlantic Oscillation on the climate systems in the south and north, as well as differences in local climate. Spectral analysis and series comparison suggest that the drought variation in the northeastern Tibetan Plateau has been possibly influenced by solar activity on centurial and longer time scale.

Evolutionary history of a vanishing radiation: isolation-dependent persistence and diversification in Pacific Island partulid tree snails.

Science.gov (United States)

Lee, Taehwan; Li, Jingchun; Churchill, Celia K C; Foighil, Diarmaid Ó

2014-09-24

Partulid tree snails are endemic to Pacific high islands and have experienced extraordinary rates of extinction in recent decades. Although they collectively range across a 10,000 km swath of Oceania, half of the family's total species diversity is endemic to a single Eastern Pacific hot spot archipelago (the Society Islands) and all three partulid genera display highly distinctive distributions. Our goal was to investigate broad scale (range wide) and fine scale (within-Society Islands) molecular phylogenetic relationships of the two widespread genera, Partula and Samoana. What can such data tell us regarding the genesis of such divergent generic distribution patterns, and nominal species diversity levels across Oceania? Museum, captive (zoo) and contemporary field specimens enabled us to genotype 54 of the ~120 recognized species, including many extinct or extirpated taxa, from 14 archipelagoes. The genera Partula and Samoana are products of very distinct diversification processes. Originating at the western edge of the familial range, the derived genus Samoana is a relatively recent arrival in the far eastern archipelagoes (Society, Austral, Marquesas) where it exhibits a stepping-stone phylogenetic pattern and has proven adept at both intra-and inter- archipelago colonization. The pronounced east-west geographic disjunction exhibited by the genus Partula stems from a much older long-distance dispersal event and its high taxonomic diversity in the Society Islands is a product of a long history of within-archipelago diversification. The central importance of isolation for partulid lineage persistence and diversification is evident in time-calibrated phylogenetic trees that show that remote archipelagoes least impacted by continental biotas bear the oldest clades and/or the most speciose radiations. In contemporary Oceania, that isolation is being progressively undermined and these tree snails are now directly exposed to introduced continental predators

Monitoring Million Trees LA: Tree performance during the early years and future benefits

Science.gov (United States)

E. Gregory McPherson

2014-01-01

Million Trees LA (MTLA) is one of several large-scale mayoral tree planting initiatives striving to create more livable cities through urban forestry. This study combined field sampling of tree survival and growth with numerical modeling of future benefits to assess performance of MTLA plantings. From 2006 to 2010 MTLA planted a diverse mix of 91,786 trees....

Interspecific differences and commonalities in maternity roosting by tree cavity-roosting bats over a maternity season in a timber production landscape.

Science.gov (United States)

Rueegger, Niels; Law, Brad; Goldingay, Ross

2018-01-01

Understanding maternity roost requirements is fundamental to guide timber production forest management given such roosts are vital to sustain bat populations. We tracked lactating females of three tree cavity-roosting species: Gould's long-eared bat (Nyctophilus gouldi) (n = 7), eastern broad-nosed bat (Scotorepens orion) (n = 6) and little forest bat (Vespadelus vulturnus) (n = 25), over five weeks in young (predominately maternity roost selection in a regenerating landscape and by doing so, increase our understanding of the three species' roost ecology. Sixteen V. vulturnus, 15 N. gouldi and six S. orion unique maternity roost trees were located. Bats displayed a degree of maternity roost selection plasticity, however, interspecific differences were found. Nyctophilus gouldi roosted selectively in retained riparian buffers, in trees of high senescence and switched roosts every day. Vespadelus vulturnus roosted in logged areas and displayed high roost site fidelity, with one roost used for 33 consecutive days. Scotorepens orion selected large live trees of low senescence. The preliminary data for this species suggests that females roost most days in 'primary' roosts but display a roost switching behaviour conforming to the fission-fusion model. Dead trees were identified to be important for both N. gouldi and V. vulturnus. Historical and recent logging at our study area drastically reduced cavity-bearing tree density to 1.4 trees per hectare in the logging zones (outside of exclusion areas), potentially limiting local populations of tree cavity-roosting bats and other cavity-dependent wildlife. Our data demonstrate that forest management must consider a range of maternity roost requirements to accommodate differences among species and highlight the importance of exclusion areas for roost habitat. We propose that an expanded 'retention forestry' approach should be implemented in logged areas that includes in-perpetuity forest patch retention to increase habitat

Eastern European retailers and wholesalers' buying behaviour

DEFF Research Database (Denmark)

Esbjerg, Lars; Stacey, Julia

1999-01-01

During the last ten years, retailing in Eastern Europe has undergone considerable changes. The entry of Western European retail chains into Eastern Europe has helped accelerate the distributive trade of Eastern Europe. But what does it take to sell fish and cheese to retailers and wholesalers...... in Eastern Europe compared to Western Europe? Eastern European buyers attach great importance to other aspects when they list new suppliers and products than does Western European retailing. These are the results of a MAPP study of Eastern European retail and wholesale buying behaviour for fish and cheese....... Low prices and favourable terms of payment are most important when retailers in Eastern Europe buy fish and cheese. Then follows the supplier's range of products, trustworthiness of the supplier and product quality. Eastern European wholesalers also rank price and financial conditions as most...

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...

The ghosts of trees past: savanna trees create enduring legacies in plant species composition.

Science.gov (United States)

Stahlheber, Karen A; Crispin, Kimberly L; Anton, Cassidy; D'Antonio, Carla M

2015-09-01

Isolated trees in savannas worldwide are known to modify their local environment and interact directly with neighboring plants. Less is known about how related tree species differ in their impacts on surrounding communities, how the effects of trees vary between years, and how composition might change following loss of the tree. To address these knowledge gaps, we explored the following questions: How do savanna trees influence the surrounding composition of herbaceous plants? Is the influence of trees consistent across different species and years? How does this change following the death of the tree? We surveyed herbaceous species composition and environmental attributes surrounding living and dead evergreen and deciduous Quercus trees in California (USA) savannas across several years that differed in their total precipitation. Oak trees of all species created distinct, homogenous understory communities dominated by exotic grasses across several sites. The composition of the low-diversity understory communities showed less interannual variation than open grassland, despite a two-fold difference in precipitation between the driest and wettest year. Vegetation composition was correlated with variation in soil properties, which were strongly affected by trees. Oaks also influenced the communities beyond the edge of the crown, but this depended on site and oak species. Low-diversity understory communities persisted up to 43 years following the death of the tree. A gradual decline in the effect of trees on the physical, environment following death did not result in vegetation becoming more similar to open grassland over time. The presence of long-lasting legacies of past tree crowns highlights the difficulty of assigning control of the current distribution of herbaceous species in grassland to their contemporary environment.

Anthropogenic nitrogen deposition ameliorates the decline in tree growth caused by a drier climate.

Science.gov (United States)

Ibáñez, Inés; Zak, Donald R; Burton, Andrew J; Pregitzer, Kurt S

2018-02-01

Most forest ecosystems are simultaneously affected by concurrent global change drivers. However, when assessing these effects, studies have mainly focused on the responses to single factors and have rarely evaluated the joined effects of the multiple aspects of environmental change. Here, we analyzed the combined effects of anthropogenic nitrogen (N) deposition and climatic conditions on the radial growth of Acer saccharum, a dominant tree species in eastern North American forests. We capitalized on a long-term N deposition study, replicated along a latitudinal gradient, that has been taking place for more than 20 yr. We analyzed tree radial growth as a function of anthropogenic N deposition (ambient and experimental addition) and of summer temperature and soil water conditions. Our results reveal that experimental N deposition enhances radial growth of this species, an effect that was accentuated as temperature increased and soil water became more limiting. The spatial and temporal extent of our data also allowed us to assert that the positive effects of growing under the experimental N deposition are likely due to changes in the physiological performance of this species, and not due to the positive correlation between soil N and soil water holding capacity, as has been previously speculated in other studies. Our simulations of tree growth under forecasted climate scenarios specific for this region also revealed that although anthropogenic N deposition may enhance tree growth under a large array of environmental conditions, it will not mitigate the expected effects of growing under the considerably drier conditions characteristic of our most extreme climatic scenario. © 2018 by the Ecological Society of America.

Barking up the wrong tree: injuries due to falls from trees in Solomon Islands.

Science.gov (United States)

Negin, Joel; Vizintin, Pavle; Houasia, Patrick; Martiniuk, Alexandra L C

2014-12-11

To investigate tree-related injuries in Solomon Islands by the types of trees involved, who is affected and the types of injuries caused. Descriptive case series of all cases of injuries related to trees presenting to the National Referral Hospital in Honiara from 1994 to 2011. Data were collected by the attending clinician using a Trauma Epidemiology form, which provides information on age, sex, cause of injury and type of fracture. Number of injuries by tree type, sex and age. Of the 7651 injuries in the database, 1107 (14%) were caused by falls from trees. Falls from coconut trees led to the highest number of injuries, followed by falls from mango, guava, apple and nut trees. Overall, 85% of injuries occurred in individuals aged trees, 77% of patients were aged tree types. Overall, 71% of injuries occurred among males. Of all injuries, 92% were fractures, 3% were dislocations and 5% were non-fracture, non-dislocation injuries. The arm (including wrist, elbow and hand) was the most common location of injury across all tree types. Distal radius fractures in the forearm were particularly common, as were ulna fractures. While mangos and guavas are undeniably delicious, the quest for their flesh can be hazardous. Children will always climb trees, but the search for food among children in lower-income settings may lead to higher rates of injury.

Intercontinental and intracontinental biogeography of the eastern Asian - Eastern North American disjunct Panax (the ginseng genus, Araliaceae), emphasizing its diversification processes in eastern Asia.

Science.gov (United States)

Zuo, Yun-Juan; Wen, Jun; Zhou, Shi-Liang

2017-12-01

The intercontinental biogeography between eastern Asia and eastern North America has attracted much attention from evolutionary biologists. Further insights into understanding the evolution of the intercontinental disjunctions have been hampered by the lack of studies on the intracontinental biogeography in eastern Asia, a region with complex geology, geography, climates and habitats. Herein we studied the biogeographic history of the eastern Asian-eastern North American disjunct genus Panax with special emphasis on the investigation of its uneven diversification in Asia. This study reconstructs the diversification history of Panax and also emphasizes a large clade of Panax taxa, which has a wide distribution in eastern Asia, but was unresolved in previous studies. We examined the noncoding plastid DNA fragments of trnH-psbA, rps16, and psbM-trnD, the mitochondrial b/c intron of NAD1, and the nuclear ribosomal internal transcribed spacer (ITS) region of 356 samples from 47 populations. The results revealed the subtropical Northern Hemisphere origin (Asia or Asia and North America) of Panax in the Paleocene. Intercontinental disjunctions between eastern Asia and eastern North America formed twice in Panax, once estimated in early Eocene for the split of P. trifolius and another in mid-Miocene for the divergence of P. quinquefolius. Intercontinental diversifications in Panax showed temporal correlation with the increase of global temperature. The evolutionary radiation of the P. bipinnatifidus species complex occurred around the boundary of Oligocene and Miocene. Strong genetic structure among populations of the species complex was detected and the populations may be isolated by distance. The backbone network and the Bayesian clustering analysis revealed a major evolutionary radiation centered in the Hengduan Mountains of western China. Our results suggested that the evolutionary radiation of Panax was promoted by geographic barriers, including mountain ranges

Recursive Trees for Practical ORAM

Directory of Open Access Journals (Sweden)

Moataz Tarik

2015-06-01

Full Text Available We present a new, general data structure that reduces the communication cost of recent tree-based ORAMs. Contrary to ORAM trees with constant height and path lengths, our new construction r-ORAM allows for trees with varying shorter path length. Accessing an element in the ORAM tree results in different communication costs depending on the location of the element. The main idea behind r-ORAM is a recursive ORAM tree structure, where nodes in the tree are roots of other trees. While this approach results in a worst-case access cost (tree height at most as any recent tree-based ORAM, we show that the average cost saving is around 35% for recent binary tree ORAMs. Besides reducing communication cost, r-ORAM also reduces storage overhead on the server by 4% to 20% depending on the ORAM’s client memory type. To prove r-ORAM’s soundness, we conduct a detailed overflow analysis. r-ORAM’s recursive approach is general in that it can be applied to all recent tree ORAMs, both constant and poly-log client memory ORAMs. Finally, we implement and benchmark r-ORAM in a practical setting to back up our theoretical claims.

Comparing the use of live trees and deadwood for larval foraging by aye-ayes (Daubentonia madagascariensis) at Kianjavato and Torotorofotsy, Madagascar.

Science.gov (United States)

Sefczek, Timothy M; Randimbiharinirina, Domenico; Raharivololona, Brigitte M; Rabekianja, Joseph D; Louis, Edward E

2017-10-01

Aye-aye (Daubentonia madagascariensis) feeding behavior has become synonymous with deadwood foraging. However, deadwood is not always the most frequently used substrate, as some aye-ayes use live trees more often to access invertebrates. We sought to compare the frequency of aye-aye invertebrate foraging in deadwood and live trees to better understand their feeding behaviors. We followed two male aye-ayes at Kianjavato, a heavily disturbed habitat in southeastern Madagascar, from October 2013 to October 2014, and one male and one female aye-aye at Torotorofotsy, a continuous forest in eastern Madagascar, from July 2014 to December 2015. We collected feeding data by recording the behavior of a focal aye-aye every 5 min for a total of 373 h at Kianjavato and 383 h at Torotorofotsy. Our results showed no difference in the amount of deadwood used between the individuals. However, there was a significant difference in the amount of live tree feeding between the female at Torotorofotsy and one of the males at Kianjavato. We conclude that feeding on invertebrates in live trees is more important to aye-ayes than previously realized and that aye-ayes are exceedingly flexible in their invertebrate feeding behaviors, adjusting to their habitat by using various substrates.

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.

City of Pittsburgh Trees

Data.gov (United States)

Allegheny County / City of Pittsburgh / Western PA Regional Data Center — Trees cared for and managed by the City of Pittsburgh Department of Public Works Forestry Division. Tree Benefits are calculated using the National Tree Benefit...

Flowering Trees

Indian Academy of Sciences (India)

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Flowering Trees. Gliricidia sepium(Jacq.) Kunta ex Walp. (Quickstick) of Fabaceae is a small deciduous tree with. Pinnately compound leaves. Flower are prroduced in large number in early summer on terminal racemes. They are attractive, pinkish-white and typically like bean flowers. Fruit is a few-seeded flat pod.

Drawing Trees

DEFF Research Database (Denmark)