Seeing the Forest of Information for the Trees of Papers: An Information Literacy Case Study in a Geography/Geology Class

ERIC Educational Resources Information Center

Blake, Linda; Warner, Tim

2011-01-01

After receiving a mini-grant for developing integrated information literacy programs, a Geography/Geology Department faculty member worked with the Science Librarian to embed information literacy in a cross-listed geology and geography course, Geog/Geol 455, Introduction to Remote Sensing. Planning for the revisions to the class started with…

Uav-Based Automatic Tree Growth Measurement for Biomass Estimation

NASA Astrophysics Data System (ADS)

Karpina, M.; Jarząbek-Rychard, M.; Tymków, P.; Borkowski, A.

2016-06-01

Manual in-situ measurements of geometric tree parameters for the biomass volume estimation are time-consuming and economically non-effective. Photogrammetric techniques can be deployed in order to automate the measurement procedure. The purpose of the presented work is an automatic tree growth estimation based on Unmanned Aircraft Vehicle (UAV) imagery. The experiment was conducted in an agriculture test field with scots pine canopies. The data was collected using a Leica Aibotix X6V2 platform equipped with a Nikon D800 camera. Reference geometric parameters of selected sample plants were measured manually each week. In situ measurements were correlated with the UAV data acquisition. The correlation aimed at the investigation of optimal conditions for a flight and parameter settings for image acquisition. The collected images are processed in a state of the art tool resulting in a generation of dense 3D point clouds. The algorithm is developed in order to estimate geometric tree parameters from 3D points. Stem positions and tree tops are identified automatically in a cross section, followed by the calculation of tree heights. The automatically derived height values are compared to the reference measurements performed manually. The comparison allows for the evaluation of automatic growth estimation process. The accuracy achieved using UAV photogrammetry for tree heights estimation is about 5cm.

Revisiting the direct detection of dark matter in simplified models

NASA Astrophysics Data System (ADS)

Li, Tong

2018-07-01

In this work we numerically re-examine the loop-induced WIMP-nucleon scattering cross section for the simplified dark matter models and the constraint set by the latest direct detection experiment. We consider a fermion, scalar or vector dark matter component from five simplified models with leptophobic spin-0 mediators coupled only to Standard Model quarks and dark matter particles. The tree-level WIMP-nucleon cross sections in these models are all momentum-suppressed. We calculate the non-suppressed spin-independent WIMP-nucleon cross sections from loop diagrams and investigate the constrained space of dark matter mass and mediator mass by Xenon1T. The constraints from indirect detection and collider search are also discussed.

Ana o 1 and Ana o 2 cashew allergens share cross-reactive CD4+ T-cell epitopes with other tree nuts

PubMed Central

Archila, Luis Diego; Chow, I-Ting; McGinty, John W.; Renand, Amedee; Jeong, David; Robinson, David; Farrington, Mary L.; Kwok, William.W.

2017-01-01

Background Allergies to cashew are increasing in prevalence, with clinical symptoms ranging from oral pruritus to fatal anaphylactic reaction. Yet, cashew-specific T-cell epitopes and T-cell cross-reactivity amongst cashew and other tree nut allergens in humans remain uncharacterized. Objectives In this study, we characterized cashew specific T-cell responses in cashew allergic subjects and examined cross-reactivity of these cashew specific cells toward other tree nut allergens. Methods CD154 up-regulation assay was used to determine immunodominance hierarchy among cashew major allergens at the T cell level. The phenotype, magnitude and functionality of cashew-specific T-cells was determined by utilizing ex vivo staining with MHC class II tetramers. Dual tetramer staining and proliferation experiments were used to determine cross-reactivity to other tree nuts. Results CD4+ T-cell responses were directed towards cashew allergens Ana o 1 and Ana o 2. Multiple Ana o 1 and Ana o 2 T-cell epitopes were then identified. These epitopes elicited either TH2 or TH2/TH17 responses in allergic subjects, which were either cashew unique epitope or cross-reactive epitopes. For clones that recognized the cross-reactive epitope, T-cell clones responded robustly to cashew, hazelnut and/or pistachio but not to walnut. Conclusions Phylogenetically diverse tree nut allergens can activate cashew reactive T-cells and elicit a TH2 type response at an epitope specific level. Clinical relevance Lack of cross-reactivity between walnut and cashew suggest that cashew peptide immunotherapy approach may not be most effective for walnut. PMID:27129138

Ana o 1 and Ana o 2 cashew allergens share cross-reactive CD4(+) T cell epitopes with other tree nuts.

PubMed

Archila, L D; Chow, I-T; McGinty, J W; Renand, A; Jeong, D; Robinson, D; Farrington, M L; Kwok, W W

2016-06-01

Allergies to cashew are increasing in prevalence, with clinical symptoms ranging from oral pruritus to fatal anaphylactic reaction. Yet, cashew-specific T cell epitopes and T cell cross-reactivity amongst cashew and other tree nut allergens in humans remain uncharacterized. In this study, we characterized cashew-specific T cell responses in cashew-allergic subjects and examined cross-reactivity of these cashew-specific cells towards other tree nut allergens. CD154 up-regulation assay was used to determine immunodominance hierarchy among cashew major allergens at the T cell level. The phenotype, magnitude and functionality of cashew-specific T cells were determined by utilizing ex vivo staining with MHC class II tetramers. Dual tetramer staining and proliferation experiments were used to determine cross-reactivity to other tree nuts. CD4(+) T cell responses were directed towards cashew allergens Ana o 1 and Ana o 2. Multiple Ana o 1 and Ana o 2 T cell epitopes were then identified. These epitopes elicited either TH 2 or TH 2/TH 17 responses in allergic subjects, which were either cashew unique epitope or cross-reactive epitopes. For clones that recognized the cross-reactive epitope, T cell clones responded robustly to cashew, hazelnut and/or pistachio but not to walnut. Phylogenetically diverse tree nut allergens can activate cashew-reactive T cells and elicit a TH 2-type response at an epitope-specific level. Lack of cross-reactivity between walnut and cashew suggests that cashew peptide immunotherapy approach may not be most effective for walnut. © 2016 John Wiley & Sons Ltd.

Climatic response of annual tree-rings

NASA Astrophysics Data System (ADS)

Ageev, Boris G.; Gruzdev, Aleksandr N.; Ponomarev, Yurii N.; Sapozhnikova, Valeria A.

2014-11-01

Extensive literature devoted to investigations into the influence of environmental conditions on the plant respiration and respiration rate. It is generally accepted that the respired CO2 generated in a stem completely diffuses into the atmosphere. Results obtained from explorations into the CO2 content in disc tree rings by the method proposed in this work shows that a major part of CO2 remains in tree stems and exhibits inter-annual variability. Different methods are used to describe of CO2 and H2O distributions in disc tree rings. The relation of CO2 and H2O variations in a Siberian stone pine disc to meteorological parameters are analyzed with use of wavelet, spectral and cross-spectral techniques. According to a multiple linear regression model, the time evolution of the width of Siberian stone pine rings can be partly explained by a combined influence of air temperature, precipitation, cloudiness and solar activity. Conclusions are made regarding the response of the CO2 and H2O content in coniferous tree disc rings to various climatic factors. Suggested method of CO2, (CO2+H2O) detection can be used for studying of a stem respiration in ecological risk areas.

Monitoring Seasonal Evapotranspiration in Vulnerable Agriculture using Time Series VHSR Satellite Data

NASA Astrophysics Data System (ADS)

Dalezios, Nicolas; Spyropoulos, Nicos V.; Tarquis, Ana M.

2015-04-01

The research work stems from the hypothesis that it is possible to perform an estimation of seasonal water needs of olive tree farms under drought periods by cross correlating high spatial, spectral and temporal resolution (~monthly) of satellite data, acquired at well defined time intervals of the phenological cycle of crops, with ground-truth information simultaneously applied during the image acquisitions. The present research is for the first time, demonstrating the coordinated efforts of space engineers, satellite mission control planners, remote sensing scientists and ground teams to record at specific time intervals of the phenological cycle of trees from ground "zero" and from 770 km above the Earth's surface, the status of plants for subsequent cross correlation and analysis regarding the estimation of the seasonal evapotranspiration in vulnerable agricultural environment. The ETo and ETc derived by Penman-Montieth equation and reference Kc tables, compared with new ETd using the Kc extracted from the time series satellite data. Several vegetation indices were also used especially the RedEdge and the chlorophyll one based on WorldView-2 RedEdge and second NIR bands to relate the tree status with water and nutrition needs. Keywords: Evapotransipration, Very High Spatial Resolution - VHSR, time series, remote sensing, vulnerability, agriculture, vegetation indeces.

Wind-Induced Reconfigurations in Flexible Branched Trees

NASA Astrophysics Data System (ADS)

Ojo, Oluwafemi; Shoele, Kourosh

2017-11-01

Wind induced stresses are the major mechanical cause of failure in trees. We know that the branching mechanism has an important effect on the stress distribution and stability of a tree in the wind. Eloy in PRL 2011, showed that Leonardo da Vinci's original observation which states the total cross section of branches is conserved across branching nodes is the best configuration for resisting wind-induced fracture in rigid trees. However, prediction of the fracture risk and pattern of a tree is also a function of their reconfiguration capabilities and how they mitigate large wind-induced stresses. In this studies through developing an efficient numerical simulation of flexible branched trees, we explore the role of the tree flexibility on the optimal branching. Our results show that the probability of a tree breaking at any point depends on both the cross-section changes in the branching nodes and the level of tree flexibility. It is found that the branching mechanism based on Leonardo da Vinci's original observation leads to a uniform stress distribution over a wide range of flexibilities but the pattern changes for more flexible systems.

Applying isozyme analyses in tree-breeding programs

Treesearch

W. T. Adams

1981-01-01

Four examples illustrate the potential for practical use of isozyme analyses in applied breeding programs. These include identifying parent trees and clones, seed sources, and parentage of controlled crosses, and evaluating the effectiveness of different procedures involving open-pollination to produce seed of specific crosses. The improved ability to assess the true...

A method to improve tree water use estimates by distinguishing sapwood from heartwood using Electrical Resistivity Tomography

NASA Astrophysics Data System (ADS)

Guyot, A.; Ostergaard, K.; Lenkopane, M.; Fan, J.; Lockington, D. A.

2011-12-01

Estimating whole-plant water use in trees requires reliable and accurate methods. Measuring sap velocity and extrapolating to tree water use is seen as the most commonly used. However, deducing the tree water use from sap velocity requires an estimate of the sapwood area. This estimate is the highest cause of uncertainty, and can reach more than 50 % of the uncertainty in the estimate of water use per day. Here, we investigate the possibility of using Electrical Resistivity Tomography to evaluate the sapwood area distribution in a plantation of Pinus elliottii. Electric resistivity tomographs of Pinus elliottii show a very typical pattern of electrical resistivity, which is highly correlated to sapwood and heartwood distribution. To identify the key factors controlling the variation of electrical resistivity, cross sections at breast height for ten trees have been monitored with electrical resistivity tomography. Trees have been cut down after the experiment to identify the heartwood/sapwood boundaries and to extract wood and sap samples. pH, electrolyte concentration and wood moisture content have then been analysed for these samples. Results show that the heartwood/sapwood patterns are highly correlated with electrical resistivity, and that the wood moisture content is the most influencing factor controlling the variability of the patterns. These results show that electric resistivity tomography could be used as a powerful tool to identify the sapwood area, and thus be used in combination with sapflow sensors to map tree water use at stand scale. However, if Pinus elliottii shows typical patterns, further work is needed to identify to see if there are species - specific characterictics as shown in previous works (, electrolyte gradients from the bark to the heartwood). Also, patterns of high resistivity in between needles positions, which are not correlated with either wood moisture content or sapwood, appear to be artifacts. Thus, inversion methods have also to be improved to take into account these measurements issues.

Height growth in western white pine progenies

Treesearch

G. E. Rehfeldt; R. J. Steinhoff

1970-01-01

Heights of 31 progenies of western white pines from four geographic localities and four crosses between localities were assessed on 14-year-old trees at two sites. Differences in height among individual progenies were detected but could not be related to localities or crosses between localities. Although differential effects of sites on tree height became apparent...

Cross-reactivity profiles of legumes and tree nuts using the xMAP® multiplex food allergen detection assay.

PubMed

Cho, Chung Y; Oles, Carolyn; Nowatzke, William; Oliver, Kerry; Garber, Eric A E

2017-10-01

The homology between proteins in legumes and tree nuts makes it common for individuals with food allergies to be allergic to multiple legumes and tree nuts. This propensity for allergenic and antigenic cross-reactivity means that commonly employed commercial immunodiagnostic assays (e.g., dipsticks) for the detection of food allergens may not always accurately detect, identify, and quantitate legumes and tree nuts unless additional orthogonal analytical methods or secondary measures of analysis are employed. The xMAP ® Multiplex Food Allergen Detection Assay (FADA) was used to determine the cross-reactivity patterns and the utility of multi-antibody antigenic profiling to distinguish between legumes and tree nuts. Pure legumes and tree nuts extracted using buffered detergent displayed a high level of cross-reactivity that decreased upon dilution or by using a buffer (UD buffer) designed to increase the stringency of binding conditions and reduce the occurrence of false positives due to plant-derived lectins. Testing for unexpected food allergens or the screening for multiple food allergens often involves not knowing the identity of the allergen present, its concentration, or the degree of modification during processing. As such, the analytical response measured may represent multiple antigens of varying antigenicity (cross-reactivity). This problem of multiple potential analytes is usually unresolved and the focus becomes the primary analyte, the antigen the antibody was raised against, or quantitative interpretation of the content of the analytical sample problematic. The alternative solution offered here to this problem is the use of an antigenic profile as generated by the xMAP FADA using multiple antibodies (bead sets). By comparing the antigenic profile to standards, the allergen may be identified along with an estimate of the concentration present. Cluster analysis of the xMAP FADA data was also performed and agreed with the known phylogeny of the legumes and tree nuts being analyzed. Graphical abstract The use of cluster analysis to compare the multi-antigen profiles of food allergens.

Cross-scale interactions affect tree growth and intrinsic water ...

EPA Pesticide Factsheets

1. We investigated the potential of cross-scale interactions to affect the outcome of density reduction in a large-scale silvicultural experiment. 2. We measured tree growth and intrinsic water-use efficiency (iWUE) based on stable carbon isotopes (13C) to investigate the impacts of thinning across a range of progressively finer spatial scales: site, stand, hillslope position, and neighborhood position. In particular, we focused on the influence of thinning beyond the boundaries of thinned stands to include impacts on downslope and neighboring stands across sites varying in soil moisture. 3. Trees at the wet site responded to thinning with increased growth when compared with trees at the dry site. Additionally, trees in thinned stands at the dry site responded with increased iWUE while trees in thinned stands at the wet site showed no difference in iWUE compared to unthinned stands. 4. We hypothesized that water is not the primary limiting factor for growth at our sites, but that thinning released other resources, such as growing space or nutrients to drive the growth response. At progressively finer spatial scales we found that the responses of trees was not driven by hillslope location (i.e., downslope of thinning) but to changes in local neighborhood tree density. 5. The results of this study demonstrated that water can be viewed as an “agent” that allows us to investigate cross-scale interactions as it links coarse to finer spatial scales and vice ver

Pollen dispersion of some forest trees

Treesearch

Jonathan W. Wright

1952-01-01

The distance the pollen of forest trees travels is of practical and theoretical importance not only in tree breeding, but also in silviculture. For example, one way to produce elite or hybrid tree seed where vegetative propagation is impractical is by the establishment of "seed orchards" or natural-crossing plots. The success of such orchards will depend...

Associations between heat exposure, vigilance, and balance performance in summer tree fruit harvesters.

PubMed

Spector, June T; Krenz, Jennifer; Calkins, Miriam; Ryan, Dawn; Carmona, Jose; Pan, Mengjie; Zemke, Anna; Sampson, Paul D

2018-02-01

We sought to evaluate potential mediators of the relationship between heat exposure and traumatic injuries in outdoor agricultural workers. Linear mixed models were used to estimate associations between maximum work-shift Wet Bulb Globe Temperature (WBGT max ) and post-shift vigilance (reaction time) and postural sway (total path length) in a cross-sectional sample of 46 Washington State tree fruit harvesters in August-September 2015. The mean (SD) WBGT max was 27.4 (3.2)°C in August and 21.2 (2.0)°C in September. The mean pre-work-shift participant urine specific gravity indicated minimal dehydration. Twenty-four percent of participants exhibited possible excessive sleepiness. There was no association between WBGT max and post-shift reaction time or total path length. Heat exposure was not associated with impaired vigilance or balance in this study, in which the overall mean (SD) WBGT max was 25.9 (4.2)°C. However, the study identified opportunities to ensure adequate pre-work-shift hydration and to optimize sleep and work-shift timing in order to reduce occupational injury and heat-related illness risk. Copyright © 2017 Elsevier Ltd. All rights reserved.

Towards a Next-Generation Catalogue Cross-Match Service

NASA Astrophysics Data System (ADS)

Pineau, F.; Boch, T.; Derriere, S.; Arches Consortium

2015-09-01

We have been developing in the past several catalogue cross-match tools. On one hand the CDS XMatch service (Pineau et al. 2011), able to perform basic but very efficient cross-matches, scalable to the largest catalogues on a single regular server. On the other hand, as part of the European project ARCHES1, we have been developing a generic and flexible tool which performs potentially complex multi-catalogue cross-matches and which computes probabilities of association based on a novel statistical framework. Although the two approaches have been managed so far as different tracks, the need for next generation cross-match services dealing with both efficiency and complexity is becoming pressing with forthcoming projects which will produce huge high quality catalogues. We are addressing this challenge which is both theoretical and technical. In ARCHES we generalize to N catalogues the candidate selection criteria - based on the chi-square distribution - described in Pineau et al. (2011). We formulate and test a number of Bayesian hypothesis which necessarily increases dramatically with the number of catalogues. To assign a probability to each hypotheses, we rely on estimated priors which account for local densities of sources. We validated our developments by comparing the theoretical curves we derived with the results of Monte-Carlo simulations. The current prototype is able to take into account heterogeneous positional errors, object extension and proper motion. The technical complexity is managed by OO programming design patterns and SQL-like functionalities. Large tasks are split into smaller independent pieces for scalability. Performances are achieved resorting to multi-threading, sequential reads and several tree data-structures. In addition to kd-trees, we account for heterogeneous positional errors and object's extension using M-trees. Proper-motions are supported using a modified M-tree we developed, inspired from Time Parametrized R-trees (TPR-tree). Quantitative tests in comparison with the basic cross-match will be presented.

Channel-dynamic control on the establishment of riparian trees after large floods in northwestern California

Treesearch

Thomas E. Lisle

1989-01-01

Abstract - Large floods in northwestern California in the past two decades have mobilized extensive areas of valley floors, removed streamside trees, and widened channels. Channel cross sections were surveyed to illustrate an hypothesis on the linkage between sediment transport, colonization of channel margins by trees, and streambank recovery. Riparian trees, e.g.,...

Evaluation of acoustic tomography for tree decay detection

Treesearch

Shanquing Liang; Xiping Wang; Janice Wiedenbeck; Zhiyong Cai; Feng Fu

2008-01-01

In this study, the acoustic tomography technique was used to detect internal decay in high value black cherry (Prunus seratina) trees. Two-dimensional images of the cross sections of the tree samples were constructed using PiCUS Q70 software. The trees were felled following the field test, and a disc from each testing elevation was subsequently cut...

A window of opportunity for climate-change adaptation: easing tree mortality by reducing forest basal area

Treesearch

John B Bradford; David M Bell

2016-01-01

Increasing aridity as a result of climate change is expected to exacerbate tree mortality. Reducing forest basal area – the cross-sectional area of tree stems within a given ground area – can decrease tree competition, which may reduce drought-induced tree mortality. However, neither the magnitude of expected mortality increases, nor the potential effectiveness of...

Genetic basis of aboveground productivity in two native Populus species and their hybrids.

PubMed

Lojewski, Nathan R; Fischer, Dylan G; Bailey, Joseph K; Schweitzer, Jennifer A; Whitham, Thomas G; Hart, Stephen C

2009-09-01

Demonstration of genetic control over riparian tree productivity has major implications for responses of riparian systems to shifting environmental conditions and effects of genetics on ecosystems in general. We used field studies and common gardens, applying both molecular and quantitative techniques, to compare plot-level tree aboveground net primary productivity (ANPP(tree)) and individual tree growth rate constants in relation to plant genetic identity in two naturally occurring Populus tree species and their hybrids. In field comparisons of four cross types (Populus fremontii S. Wats., Populus angustifolia James, F(1) hybrids and backcross hybrids) across 11 natural stands, productivity was greatest for P. fremontii trees, followed by hybrids and lowest in P. angustifolia. A similar pattern was observed in four common gardens across a 290 m elevation and 100 km environmental gradient. Despite a doubling in productivity across the common gardens, the relative differences among the cross types remained constant. Using clonal replicates in a common garden, we found ANPP(tree) to be a heritable plant trait (i.e., broad-sense heritability), such that plant genetic factors explained between 38% and 82% of the variation in ANPP(tree). Furthermore, analysis of the genetic composition among individual tree genotypes using restriction fragment length polymorphism molecular markers showed that genetically similar trees also exhibited similar ANPP(tree). These findings indicate strong genetic contributions to natural variation in ANPP with important ecological implications.

Cross-scale interactions affect tree growth and intrinsic water use efficiency and highlight the importance of spatial context in managing forests under global change

EPA Science Inventory

1. We investigated the potential of cross-scale interactions to affect the outcome of density reduction in a large-scale silvicultural experiment. 2. We measured tree growth and intrinsic water-use efficiency (iWUE) based on stable carbon isotopes (13C) to investigate the...

Cross Layered Multi-Meshed Tree Scheme for Cognitive Networks

DTIC Science & Technology

2011-06-01

Meshed Tree Routing protocol wireless ad hoc networks ,” Second IEEE International Workshop on Enabling Technologies and Standards for Wireless Mesh ...and Sensor Networks , 2004 43. Chen G.; Stojmenovic I., “Clustering and routing in mobile wireless networks ,” Technical Report TR-99-05, SITE, June...Cross-layer optimization, intra-cluster routing , packet forwarding, inter-cluster routing , mesh network communications,

77 FR 71825 - Notice of Temporary Restriction of Vehicle Use and Temporary Closure to Tree Cutting and Wood...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-04

... to Tree Cutting and Wood Harvesting on Public Land in Douglas County, NV AGENCY: Bureau of Land... a temporary closure to wood harvesting and/or tree cutting on public land within the Topaz Ranch... temporary restriction of cross-country vehicle travel and a temporary closure to tree cutting and wood...

Channel-Dynamic Control on the Establishment of Riparian Trees After Large Floods in Northwestern California

Treesearch

Thomas E. Lisle

1989-01-01

Large floods in northwestern California in the past two decades have mobilized extensive areas of valley floors, removed streamside trees, and widened channels. Channel cross sections were surveyed to illustrate an hypothesis on the linkage between sediment transport, colonization of channel margins by trees, and streambank recovery. Riparian trees, e.g., white alder...

Nondestructive detection of decay in living trees

Treesearch

Bertil Larsson; Bengt Bengtsson; Mats Gustaffson

2004-01-01

We used a four-point resistivity method to detect wood decay in living trees. low-frequency alternating current was applied to the stem and the induced voltage measured between two points along the stem. The effective resistivity of the stem was estimated based on stem cross-sectional area. A comparison within a group of trees showed that trees with butt rot had an...

Asthma and Allergic Rhinitis Correlation in Palm Tree Workers of Jahrom City in 2016.

PubMed

Farahmand Fard, Mohammad Amin; Khanjani, Narges; Arabi Mianroodi, Aliasghar; Ashrafi Asgarabad, Ahad

2017-05-01

Allergic rhinitis and asthma can be related to occupation. The present study aimed to investigate the correlation between asthma or allergic rhinitis and employment in the palm tree gardens of Jahrom, Iran. This was a cross-sectional study including 50 palm tree garden workers and a control group of 50 office employees. Data collection included demographics, as well as standard International Study of Asthma and Allergies in Childhood (ISAAC) and A New Symptom-Based Questionnaire for Predicting the Presence of Asthma (ASQ) questionnaires. Data were analyzed using SPSS22. Descriptive statistics, chi-square test, t-test, and logistics regression were used to analyze data. The correlation between asthma and occupation was significant ( P=0.046); and asthma prevalence was higher in palm tree garden workers. However, no relationship was observed between age, duration of employment, smoking cigarettes, hookah, or opium addiction with asthma. Furthermore, in this study, no significant relation was observed between the prevalence of asthma and contact with dust, contact with pets' skin and hair, family history of asthma, or the use of perfume and air freshener. The symptoms of allergic rhinitis (including sneezing, runny nose, and blocked nose) were significantly greater in palm tree garden workers (P=0.038). These symptoms in both workers and office employees were higher in spring. In our study, allergic rhinitis and asthma were more common in palm tree garden workers than in the general population. According to our study, people working in this occupation should take necessary precautions.

Tree Amigos.

ERIC Educational Resources Information Center

Center for Environmental Study, Grand Rapids, MI.

Tree Amigos is a special cross-cultural program that uses trees as a common bond to bring the people of the Americas together in unique partnerships to preserve and protect the shared global environment. It is a tangible program that embodies the philosophy that individuals, acting together, can make a difference. This resource book contains…

Age Distribution of Oak Forests in North-Central Arkansas

Treesearch

Rick Soucy; Eric Heitzman; Martin A. Spetich

2004-01-01

We used tree ring analysis to reconstruct the tree establishment patterns in four mature white oak (Quercus alba L.)-northern red oak (Quercus rubra L.)-hickory (Carya spp.) forests in the Ozark Mountains of north-central Arkasas. Cross sections were removed from the stumps of 321 recently harvested trees and...

Second Cross-Sectional Study of Attainment of the Concepts "Equilateral Triangle,""Cutting Tool,""Noun," and "Tree" by Children Age 6 to 16 of City B. Technical Report No. 347.

ERIC Educational Resources Information Center

Klausmeier, Herbert J.; And Others

For this study, the second in the cross sectional series, based on the Conceptual Learning and Development (CLD) model, assessment batteries were developed to determine each child's level of attainment and related use of the concepts "equilateral triangle,""cutting tool,""noun," and "tree." Batteries were…

Condition of live fire-scarred ponderosa pine eleven years after removing partial cross-sections

Treesearch

Emily K. Heyerdahl; Steven J. McKay

2008-01-01

Our objective is to report mortality rates for ponderosa pine trees in Oregon ten to eleven years after removing a fire-scarred partial cross-section from them, and five years after an initial survey of post-sampling mortality. We surveyed 138 live trees from which we removed fire-scarred partial crosssections in 1994/95 and 387 similarly sized, unsampled neighbor...

Field levels of infection of progenies of western white pines selected for blister rust resistance

Treesearch

R. J. Steinhoff

1971-01-01

Western white pine trees resulting from crosses of parents selected for phenotypic resistance to Cronartium ribicola J. C. Fisch. ex Rabenh., the white pine blister rust, were inspected for rust infection after 11 to 15 years in two field plots. When compared to controls and to natural reproduction, the progenies of crosses involving trees that exhibited general...

Analysis of the 'A72' peach tree growth habit and its inheritance in progeny obtained from crosses of 'A72' with columnar peach trees

USDA-ARS?s Scientific Manuscript database

Since the first report of the 'A72' semi-dwarf peach tree (Nn) by Monet and Salesses (1975), little information has become available on this genotype. We evaluated the growth habit and verified the inheritance of 'A72' in a population of 220 progeny derived from self-pollination. Detailed tree and ...

Olive tree-ring problematic dating: a comparative analysis on Santorini (Greece).

PubMed

Cherubini, Paolo; Humbel, Turi; Beeckman, Hans; Gärtner, Holger; Mannes, David; Pearson, Charlotte; Schoch, Werner; Tognetti, Roberto; Lev-Yadun, Simcha

2013-01-01

Olive trees are a classic component of Mediterranean environments and some of them are known historically to be very old. In order to evaluate the possibility to use olive tree-rings for dendrochronology, we examined by various methods the reliability of olive tree-rings identification. Dendrochronological analyses of olive trees growing on the Aegean island Santorini (Greece) show that the determination of the number of tree-rings is impossible because of intra-annual wood density fluctuations, variability in tree-ring boundary structure, and restriction of its cambial activity to shifting sectors of the circumference, causing the tree-ring sequences along radii of the same cross section to differ.

Habitat choice of multiple pollinators in almond trees and its potential effect on pollen movement and productivity: A theoretical approach using the Shigesada-Kawasaki-Teramoto model.

PubMed

Yong, Kamuela E; Li, Yi; Hendrix, Stephen D

2012-07-21

California's almond industry, valued at $2.3 billion per year, depends on the pollinator services of honey bees, although pollination by other insects, mainly solitary wild bees, is being investigated as an alternative because of recent declines in the number of honey bee colonies. Our objective is to model the movements of honey bees and determine the conditions under which they will forage in less favorable areas of a tree and its surroundings when other pollinators are present. We hypothesize that foraging in less favorable areas leads to increased movement between trees and increased cross pollination between varieties which is required for successful nut production. We use the Shigesada-Kawasaki-Teramoto model (1979) which describes the density of two species in a two-dimensional environment of variable favorableness with respect to intrinsic diffusions and intra and interspecific interactions of species. The model is applied to almond pollination by honey bees and other pollinators with environmental favorableness based on the distribution of flowers in trees. Using the spectral-Galerkin method in a rectangular domain, we numerically approximated the two-dimensional nonlinear parabolic partial differential system arising in the model. When cross-diffusion or interspecific effects of other pollinators was high, honey bees foraged in less favorable areas of the tree. In the model, high cross-diffusion also resulted in increased activity in honey bees which manifested itself in the field in terms of accelerations, decelerations, and changes in direction, indicating rapid redistribution of densities to an equilibrium state. Empirical analysis of the number of honey bees and other visitors in 2-min intervals to almond trees shows a negative relationship, indicating cross-diffusion effects in nature with the potential to increase movement to a different tree with a more favorable environment, potentially increasing nut production. Copyright © 2012 Elsevier Ltd. All rights reserved.

Emotional Sentence Annotation Helps Predict Fiction Genre.

PubMed

Samothrakis, Spyridon; Fasli, Maria

2015-01-01

Fiction, a prime form of entertainment, has evolved into multiple genres which one can broadly attribute to different forms of stories. In this paper, we examine the hypothesis that works of fiction can be characterised by the emotions they portray. To investigate this hypothesis, we use the work of fictions in the Project Gutenberg and we attribute basic emotional content to each individual sentence using Ekman's model. A time-smoothed version of the emotional content for each basic emotion is used to train extremely randomized trees. We show through 10-fold Cross-Validation that the emotional content of each work of fiction can help identify each genre with significantly higher probability than random. We also show that the most important differentiator between genre novels is fear.

Capturing spiral radial growth of conifers using the superellipse to model tree-ring geometric shape

PubMed Central

Shi, Pei-Jian; Huang, Jian-Guo; Hui, Cang; Grissino-Mayer, Henri D.; Tardif, Jacques C.; Zhai, Li-Hong; Wang, Fu-Sheng; Li, Bai-Lian

2015-01-01

Tree-rings are often assumed to approximate a circular shape when estimating forest productivity and carbon dynamics. However, tree rings are rarely, if ever, circular, thereby possibly resulting in under- or over-estimation in forest productivity and carbon sequestration. Given the crucial role played by tree ring data in assessing forest productivity and carbon storage within a context of global change, it is particularly important that mathematical models adequately render cross-sectional area increment derived from tree rings. We modeled the geometric shape of tree rings using the superellipse equation and checked its validation based on the theoretical simulation and six actual cross sections collected from three conifers. We found that the superellipse better describes the geometric shape of tree rings than the circle commonly used. We showed that a spiral growth trend exists on the radial section over time, which might be closely related to spiral grain along the longitudinal axis. The superellipse generally had higher accuracy than the circle in predicting the basal area increment, resulting in an improved estimate for the basal area. The superellipse may allow better assessing forest productivity and carbon storage in terrestrial forest ecosystems. PMID:26528316

Capturing spiral radial growth of conifers using the superellipse to model tree-ring geometric shape.

PubMed

Shi, Pei-Jian; Huang, Jian-Guo; Hui, Cang; Grissino-Mayer, Henri D; Tardif, Jacques C; Zhai, Li-Hong; Wang, Fu-Sheng; Li, Bai-Lian

2015-01-01

Tree-rings are often assumed to approximate a circular shape when estimating forest productivity and carbon dynamics. However, tree rings are rarely, if ever, circular, thereby possibly resulting in under- or over-estimation in forest productivity and carbon sequestration. Given the crucial role played by tree ring data in assessing forest productivity and carbon storage within a context of global change, it is particularly important that mathematical models adequately render cross-sectional area increment derived from tree rings. We modeled the geometric shape of tree rings using the superellipse equation and checked its validation based on the theoretical simulation and six actual cross sections collected from three conifers. We found that the superellipse better describes the geometric shape of tree rings than the circle commonly used. We showed that a spiral growth trend exists on the radial section over time, which might be closely related to spiral grain along the longitudinal axis. The superellipse generally had higher accuracy than the circle in predicting the basal area increment, resulting in an improved estimate for the basal area. The superellipse may allow better assessing forest productivity and carbon storage in terrestrial forest ecosystems.

"Jesus Christ the Apple Tree": Preparing for Good Friday in a Literature and Environment Course

ERIC Educational Resources Information Center

Bowen, Deborah C.

2011-01-01

This paper reflects on a visit by Christian poet John Terpstra to the final class session (on a Maundy Thursday) of my Literature and Environment course, to read his poetry suite on making a cross for his church out of a fruit-tree in an orchard being ploughed under for construction. Terpstra plays on the Stations of the Cross by interweaving the…

Variation in Loblolly pine cross-sectional microfibril angle with tree height and physiographic region

Treesearch

Lewis Jordon; Rechum Re; Daniel B. Hall; Alexander Clark; Richard F. Daniels

2006-01-01

The effect of height and physiographic region on whole disk cross-sectional microfibril angle (CSMFA) in loblolly pine (Pinus raeda L.) in the southern United States was evaluated. Whole disk CSMFA was determined at 1.4, 4.6, 7.6, 10.7, and 13.7 m up the stem of 59 trees, representing five physiographic regions. A mixed-effects analysis of variance was performed to...

Cross-scale interactions affect tree growth and intrinsic water use efficiency and highlight the importance of spatial context in managing forests under global change

Treesearch

Kenneth J. Ruzicka; Klaus J. Puettmann; J. Renée Brooks

2017-01-01

Summary1. We investigated the potential of cross-scale interactions to affect the outcome of density reduction in a large-scale silvicultural experiment to better understand options for managing forests under climate change. 2. We measured tree growth and intrinsic water-use efficiency (iWUE) based on stable carbon isotopes (δ...

Comparison of the arithmetic and geometric means in estimating crown diameter and crown cross-sectional area

Treesearch

KaDonna Randolph

2010-01-01

The use of the geometric and arithmetic means for estimating tree crown diameter and crown cross-sectional area were examined for trees with crown width measurements taken at the widest point of the crown and perpendicular to the widest point of the crown. The average difference between the geometric and arithmetic mean crown diameters was less than 0.2 ft in absolute...

Pistachio allergy-prevalence and in vitro cross-reactivity with other nuts.

PubMed

Noorbakhsh, Reihaneh; Mortazavi, Seyed Ali; Sankian, Mojtaba; Shahidi, Fakhri; Tehrani, Mohsen; Azad, Farahzad Jabbari; Behmanesh, Fatemeh; Varasteh, AbdolReza

2011-12-01

Tree nut allergy is characterized by a high frequency of life-threatening reactions and is typically lifelong persistent. Some people with a pistachio nut allergy, which is common in the pistachio rich area of Iran, develop a hypersensitivity to other tree nuts as well. The aim of this study was to investigate the prevalence of pistachio nut allergy in Iran, the major pistachio cultivation region in the world. The study also addressed the presence of allergenic cross-reactivity between pistachio and other nuts, including almond, peanut, and cashew in pistachio allergic patients. A survey was conducted to determine whether the prevalence of pistachio allergy is affected by exposure to this nut in pistachio cultivation regions, as well as possible cross-reactivity between pistachio and other nuts including cashew, almond, and peanut. Inhibition Western blot and inhibition ELISA studies were conducted to assess the presence of allergenic cross-reactivity between pistachio and the other tree nuts. Our results revealed that the prevalence of pistachio allergy is twice as much in pistachio cultivation regions than other areas. Western blotting and inhibition ELISA presented high percentages of inhibition with pistachio and cashew, followed by almond and, to some degree, peanut which indicates different levels of allergenic cross-reactivity. The results indicate that exposure of people to pistachio significantly affects the prevalence of its allergic reactions. In addition, it was observed that, among pistachio allergic subjects, such exposure may affect the co-sensitivities with other nuts, including cashew and almond. The plant taxonomic classification of pistachio and other tree nuts does appear to predict allergenic cross-reactivity.

Leonardo's Rule, Self-Similarity, and Wind-Induced Stresses in Trees

NASA Astrophysics Data System (ADS)

Eloy, Christophe

2011-12-01

Examining botanical trees, Leonardo da Vinci noted that the total cross section of branches is conserved across branching nodes. In this Letter, it is proposed that this rule is a consequence of the tree skeleton having a self-similar structure and the branch diameters being adjusted to resist wind-induced loads.

Olive Tree-Ring Problematic Dating: A Comparative Analysis on Santorini (Greece)

PubMed Central

Cherubini, Paolo; Humbel, Turi; Beeckman, Hans; Gärtner, Holger; Mannes, David; Pearson, Charlotte; Schoch, Werner; Tognetti, Roberto; Lev-Yadun, Simcha

2013-01-01

Olive trees are a classic component of Mediterranean environments and some of them are known historically to be very old. In order to evaluate the possibility to use olive tree-rings for dendrochronology, we examined by various methods the reliability of olive tree-rings identification. Dendrochronological analyses of olive trees growing on the Aegean island Santorini (Greece) show that the determination of the number of tree-rings is impossible because of intra-annual wood density fluctuations, variability in tree-ring boundary structure, and restriction of its cambial activity to shifting sectors of the circumference, causing the tree-ring sequences along radii of the same cross section to differ. PMID:23382949

A Decision Tree for Nonmetric Sex Assessment from the Skull.

PubMed

Langley, Natalie R; Dudzik, Beatrix; Cloutier, Alesia

2018-01-01

This study uses five well-documented cranial nonmetric traits (glabella, mastoid process, mental eminence, supraorbital margin, and nuchal crest) and one additional trait (zygomatic extension) to develop a validated decision tree for sex assessment. The decision tree was built and cross-validated on a sample of 293 U.S. White individuals from the William M. Bass Donated Skeletal Collection. Ordinal scores from the six traits were analyzed using the partition modeling option in JMP Pro 12. A holdout sample of 50 skulls was used to test the model. The most accurate decision tree includes three variables: glabella, zygomatic extension, and mastoid process. This decision tree yielded 93.5% accuracy on the training sample, 94% on the cross-validated sample, and 96% on a holdout validation sample. Linear weighted kappa statistics indicate acceptable agreement among observers for these variables. Mental eminence should be avoided, and definitions and figures should be referenced carefully to score nonmetric traits. © 2017 American Academy of Forensic Sciences.

Million TreesNYC: the integration of research and practice

Treesearch

Lindsay K. Campbell; Morgan Monaco; Nancy Falxa-Raymond; Jacqueline Lu; Andrew Newman; Ruth A. Rae; Erika S. Svendsen

2014-01-01

MillionTreesNYC is an ambitious campaign to plant and care for one million new trees in New York City. Implemented by the City of New York Department of Parks & Recreation and the nonprofit New York Restoration Project, this innovative, citywide effort crosses property jurisdictions and physical sites. The goal is to enhance the entire 'green matrix' of...

Respiratory and skin effects of exposure to wood dust from the rubber tree Hevea brasiliensis.

PubMed

Sripaiboonkij, P; Phanprasit, W; Jaakkola, M S

2009-07-01

Potential health effects related to wood dust from the rubber tree, which produces natural rubber latex, have not been previously investigated. The main aim of this study was to investigate the relations of rubber tree dust exposure to respiratory and skin symptoms, asthma and lung function. A cross-sectional study was conducted among 103 workers (response rate 89%) in a rubber tree furniture factory and 76 office workers (73%) in four factories in Thailand. All participants answered a questionnaire and performed spirometry. Inhalable dust levels were measured in different work areas. Factory workers showed increased risk of wheezing, nasal symptoms and asthma compared to office workers. There was a dose-dependent increase in wheeze and skin symptoms in relation to dust level. Significantly increased risks of nasal symptoms (adj OR 3.67, 95% CI 1.45 to 9.28) and asthma (8.41, 1.06 to 66.60) were detected in the low exposure category. Workers exposed to ethyl cyanoacrylate glue had significantly increased risk of cough, breathlessness and nasal symptoms. There was dose-dependent reduction in spirometric lung function with wood dust level. This study provides new evidence that workers exposed to wood dust from the rubber tree experience increased risk of nasal symptoms, wheeze, asthma and skin symptoms and have reduced spirometric lung function. Exposure to cyanoacrylate is related to significantly increased respiratory symptoms. Results suggest that the furniture industry using rubber tree wood should implement appropriate exposure control measures to reduce wood dust exposure and cyanoacrylate glue exposure to protect their employees.

Intrathoracic airway wall detection using graph search and scanner PSF information

NASA Astrophysics Data System (ADS)

Reinhardt, Joseph M.; Park, Wonkyu; Hoffman, Eric A.; Sonka, Milan

1997-05-01

Measurements of the in vivo bronchial tree can be used to assess regional airway physiology. High-resolution CT (HRCT) provides detailed images of the lungs and has been used to evaluate bronchial airway geometry. Such measurements have been sued to assess diseases affecting the airways, such as asthma and cystic fibrosis, to measure airway response to external stimuli, and to evaluate the mechanics of airway collapse in sleep apnea. To routinely use CT imaging in a clinical setting to evaluate the in vivo airway tree, there is a need for an objective, automatic technique for identifying the airway tree in the CT images and measuring airway geometry parameters. Manual or semi-automatic segmentation and measurement of the airway tree from a 3D data set may require several man-hours of work, and the manual approaches suffer from inter-observer and intra- observer variabilities. This paper describes a method for automatic airway tree analysis that combines accurate airway wall location estimation with a technique for optimal airway border smoothing. A fuzzy logic, rule-based system is used to identify the branches of the 3D airway tree in thin-slice HRCT images. Raycasting is combined with a model-based parameter estimation technique to identify the approximate inner and outer airway wall borders in 2D cross-sections through the image data set. Finally, a 2D graph search is used to optimize the estimated airway wall locations and obtain accurate airway borders. We demonstrate this technique using CT images of a plexiglass tube phantom.

Individualized Prediction of Heat Stress in Firefighters: A Data-Driven Approach Using Classification and Regression Trees.

PubMed

Mani, Ashutosh; Rao, Marepalli; James, Kelley; Bhattacharya, Amit

2015-01-01

The purpose of this study was to explore data-driven models, based on decision trees, to develop practical and easy to use predictive models for early identification of firefighters who are likely to cross the threshold of hyperthermia during live-fire training. Predictive models were created for three consecutive live-fire training scenarios. The final predicted outcome was a categorical variable: will a firefighter cross the upper threshold of hyperthermia - Yes/No. Two tiers of models were built, one with and one without taking into account the outcome (whether a firefighter crossed hyperthermia or not) from the previous training scenario. First tier of models included age, baseline heart rate and core body temperature, body mass index, and duration of training scenario as predictors. The second tier of models included the outcome of the previous scenario in the prediction space, in addition to all the predictors from the first tier of models. Classification and regression trees were used independently for prediction. The response variable for the regression tree was the quantitative variable: core body temperature at the end of each scenario. The predicted quantitative variable from regression trees was compared to the upper threshold of hyperthermia (38°C) to predict whether a firefighter would enter hyperthermia. The performance of classification and regression tree models was satisfactory for the second (success rate = 79%) and third (success rate = 89%) training scenarios but not for the first (success rate = 43%). Data-driven models based on decision trees can be a useful tool for predicting physiological response without modeling the underlying physiological systems. Early prediction of heat stress coupled with proactive interventions, such as pre-cooling, can help reduce heat stress in firefighters.

National Tree Climbing Guide [2015 Electronic Edition

Treesearch

Jerry Berdeen; Burnham Chamberlain; Teryl Grubb; Art Henderson; Brock Mayo; Manfred Mielke; Kathryn Purcell; Dennis Ringnes; Marc Roberts; Donna Stubbs; Micah Thorning

2015-01-01

The Forest Service Tree Climbing Program provides direction that protects Forest Service employees while ascending, descending, and working aloft in trees by establishing national direction based on recognized industry standards, procedures and practices. Climbing and working in trees demands specialized equipment and skills. The potential for a serious injury or fatal...

Vicilin allergens of peanut and tree nuts (walnut, hazelnut and cashew nut) share structurally related IgE-binding epitopes.

PubMed

Barre, Annick; Sordet, Camille; Culerrier, Raphaël; Rancé, Fabienne; Didier, Alain; Rougé, Pierre

2008-03-01

Surface-exposed IgE-binding epitopes of close overall conformation were characterized on the molecular surface of three-dimensional models built for the vicilin allergens of peanut (Ara h 1), walnut (Jug r 2), hazelnut (Cor a 11) and cashew nut (Ana o 1). They correspond to linear stretches of conserved amino acid sequences mainly located along the C-terminus of the polypeptide chains. A glyco-epitope corresponding to an exposed N-glycosylation site could also interfere with the IgE-binding epitopes. All these epitopic regions should participate in the IgE-binding cross-reactivity commonly reported between tree nuts or between peanut and some tree nuts in sensitized individuals. Owing to this epitopic community which constitutes a risk of cross-sensitization, the avoidance or a restricted consumption of other tree nuts should be recommended to peanut-sensitized individuals.

Dynamical mechanism in aero-engine gas path system using minimum spanning tree and detrended cross-correlation analysis

NASA Astrophysics Data System (ADS)

Dong, Keqiang; Zhang, Hong; Gao, You

2017-01-01

Identifying the mutual interaction in aero-engine gas path system is a crucial problem that facilitates the understanding of emerging structures in complex system. By employing the multiscale multifractal detrended cross-correlation analysis method to aero-engine gas path system, the cross-correlation characteristics between gas path system parameters are established. Further, we apply multiscale multifractal detrended cross-correlation distance matrix and minimum spanning tree to investigate the mutual interactions of gas path variables. The results can infer that the low-spool rotor speed (N1) and engine pressure ratio (EPR) are main gas path parameters. The application of proposed method contributes to promote our understanding of the internal mechanisms and structures of aero-engine dynamics.

Cross-Correlations and Structures of Aero-Engine Gas Path System Based on DCCA Coefficient and Rooted Tree

NASA Astrophysics Data System (ADS)

Dong, Keqiang; Fan, Jie; Gao, You

2015-12-01

Identifying the mutual interaction is a crucial problem that facilitates the understanding of emerging structures in complex system. We here focus on aero-engine dynamic as an example of complex system. By applying the detrended cross-correlation analysis (DCCA) coefficient method to aero-engine gas path system, we find that the low-spool rotor speed (N1) and high-spool rotor speed (N2) fluctuation series exhibit cross-correlation characteristic. Further, we employ detrended cross-correlation coefficient matrix and rooted tree to investigate the mutual interactions of other gas path variables. The results can infer that the exhaust gas temperature (EGT), N1, N2, fuel flow (WF) and engine pressure ratio (EPR) are main gas path parameters.

Semiautomated landscape feature extraction and modeling

NASA Astrophysics Data System (ADS)

Wasilewski, Anthony A.; Faust, Nickolas L.; Ribarsky, William

2001-08-01

We have developed a semi-automated procedure for generating correctly located 3D tree objects form overhead imagery. Cross-platform software partitions arbitrarily large, geocorrected and geolocated imagery into management sub- images. The user manually selected tree areas from one or more of these sub-images. Tree group blobs are then narrowed to lines using a special thinning algorithm which retains the topology of the blobs, and also stores the thickness of the parent blob. Maxima along these thinned tree grous are found, and used as individual tree locations within the tree group. Magnitudes of the local maxima are used to scale the radii of the tree objects. Grossly overlapping trees are culled based on a comparison of tree-tree distance to combined radii. Tree color is randomly selected based on the distribution of sample tree pixels, and height is estimated form tree radius. The final tree objects are then inserted into a terrain database which can be navigated by VGIS, a high-resolution global terrain visualization system developed at Georgia Tech.

Emotional Sentence Annotation Helps Predict Fiction Genre

PubMed Central

Samothrakis, Spyridon; Fasli, Maria

2015-01-01

Fiction, a prime form of entertainment, has evolved into multiple genres which one can broadly attribute to different forms of stories. In this paper, we examine the hypothesis that works of fiction can be characterised by the emotions they portray. To investigate this hypothesis, we use the work of fictions in the Project Gutenberg and we attribute basic emotional content to each individual sentence using Ekman’s model. A time-smoothed version of the emotional content for each basic emotion is used to train extremely randomized trees. We show through 10-fold Cross-Validation that the emotional content of each work of fiction can help identify each genre with significantly higher probability than random. We also show that the most important differentiator between genre novels is fear. PMID:26524352

A highly efficient machine planting system for forestry research plantations—the Wright-MSU method

Treesearch

James R. McKenna; Oriana Rueda-Krauss; Brian Beheler

2011-01-01

For forestry research purposes, grid planting with uniform tree spacing is superior to planting with nonuniform spacing because it controls density across the plantation and facilitates accurate repeat measurements. The ability to cross-check tree positions in a grid-type plantation avoids problems associated with dead or missing trees and increases the efficiency and...

Genetic Gains Through Testing and Crossing Longleaf Pine Plus Trees

Treesearch

Calvin F. Bey; E. Bayne Snyder

1978-01-01

A progeny test of 226 superior tree selections from nine geographic sources across the South confirmed earlier results that showed the Gulf Coast source superior in survival and growth. Family variation within a region was large and provided additional genetic gain. Control-pollinated tests of elite x elite trees yielded even more gains. Progeny of the elite x elite...

Aboveground biomass equations for 7-year-old Acacia mangium Willd in Botucatu, Brazil

Treesearch

Ricardo A. A. Veiga; Maria A. M. Brasil; Carlos M. Carvalho

2000-01-01

The biomass of steins, leaves, and branches was determined for 152 sample trees of Acacia mangium Willd were in a 7-year-old experimental plantation in Botucatu, Sao Paulo State, Brazil. After felling, dimensional measurements were taken from each tree. Cross sections were collected in 125 sample trees at ground level (0 percent), 25 percent, 50...

The Ontogeny of Gap Crossing Behaviour in Bornean Orangutans (Pongo pygmaeus wurmbii)

PubMed Central

Chappell, Jackie; Phillips, Abigail C.; van Noordwijk, Maria A.; Mitra Setia, Tatang; Thorpe, Susannah K. S.

2015-01-01

For orangutans, the largest predominantly arboreal primates, discontinuous canopy presents a particular challenge. The shortest gaps between trees lie between thin peripheral branches, which offer the least stability to large animals. The affordances of the forest canopy experienced by orangutans of different ages however, must vary substantially as adult males are an order of magnitude larger in size than infants during the early stages of locomotor independence. Orangutans have developed a diverse range of locomotor behaviour to cross gaps between trees, which vary in their physical and cognitive demands. The aims of this study were to examine the ontogeny of orangutan gap crossing behaviours and to determine which factors influence the distance orangutans crossed. A non-invasive photographic technique was used to quantify forearm length as a measure of body size. We also recorded locomotor behaviour, support use and the distance crossed between trees. Our results suggest that gap crossing varies with both physical and cognitive development. More complex locomotor behaviours, which utilized compliant trunks and lianas, were used to cross the largest gaps, but these peaked in frequency much earlier than expected, between the ages of 4 and 5 years old, which probably reflects play behaviour to perfect locomotor techniques. Smaller individuals also crossed disproportionately large gaps relative to their size, by using support deformation. Our results suggest that orangutans acquire the full repertoire of gap crossing techniques, including the more cognitively demanding ones, before weaning, but adjust the frequency of the use of these techniques to their increasing body size. PMID:26154061

The Ontogeny of Gap Crossing Behaviour in Bornean Orangutans (Pongo pygmaeus wurmbii).

PubMed

Chappell, Jackie; Phillips, Abigail C; van Noordwijk, Maria A; Mitra Setia, Tatang; Thorpe, Susannah K S

2015-01-01

For orangutans, the largest predominantly arboreal primates, discontinuous canopy presents a particular challenge. The shortest gaps between trees lie between thin peripheral branches, which offer the least stability to large animals. The affordances of the forest canopy experienced by orangutans of different ages however, must vary substantially as adult males are an order of magnitude larger in size than infants during the early stages of locomotor independence. Orangutans have developed a diverse range of locomotor behaviour to cross gaps between trees, which vary in their physical and cognitive demands. The aims of this study were to examine the ontogeny of orangutan gap crossing behaviours and to determine which factors influence the distance orangutans crossed. A non-invasive photographic technique was used to quantify forearm length as a measure of body size. We also recorded locomotor behaviour, support use and the distance crossed between trees. Our results suggest that gap crossing varies with both physical and cognitive development. More complex locomotor behaviours, which utilized compliant trunks and lianas, were used to cross the largest gaps, but these peaked in frequency much earlier than expected, between the ages of 4 and 5 years old, which probably reflects play behaviour to perfect locomotor techniques. Smaller individuals also crossed disproportionately large gaps relative to their size, by using support deformation. Our results suggest that orangutans acquire the full repertoire of gap crossing techniques, including the more cognitively demanding ones, before weaning, but adjust the frequency of the use of these techniques to their increasing body size.

VC-dimension of univariate decision trees.

PubMed

Yildiz, Olcay Taner

2015-02-01

In this paper, we give and prove the lower bounds of the Vapnik-Chervonenkis (VC)-dimension of the univariate decision tree hypothesis class. The VC-dimension of the univariate decision tree depends on the VC-dimension values of its subtrees and the number of inputs. Via a search algorithm that calculates the VC-dimension of univariate decision trees exhaustively, we show that our VC-dimension bounds are tight for simple trees. To verify that the VC-dimension bounds are useful, we also use them to get VC-generalization bounds for complexity control using structural risk minimization in decision trees, i.e., pruning. Our simulation results show that structural risk minimization pruning using the VC-dimension bounds finds trees that are more accurate as those pruned using cross validation.

Survivorship of raked and unraked trees through prescribed fires in conifer forests in northeastern California

Treesearch

William F. Laudenslayer; George N. Steger; Jonathan Arnold

2008-01-01

Large diameter, old trees are an important component of functioning forests, as they provide habitat for many wildlife species and add value to the scenery along roads and trails that cross our National Forests and Parks. Tree mortality, from prescribed or wild fire, is of great concern to forests managers, especially mortality of those of large diameter. Raking away...

Stress wave velocity patterns in the longitudinal-radial plane of trees for defect diagnosis

Treesearch

Guanghui Li; Xiang Weng; Xiaocheng Du; Xiping Wang; Hailin Feng

2016-01-01

Acoustic tomography for urban tree inspection typically uses stress wave data to reconstruct tomographic images for the trunk cross section using interpolation algorithm. This traditional technique does not take into account the stress wave velocity patterns along tree height. In this study, we proposed an analytical model for the wave velocity in the longitudinal–...

Patterns of diametric growth in stem-analyzed laurel trees (Cordia alliodora) in a Panamanian forest

Treesearch

Bernard R Parresol; Margaret S. Devall

2013-01-01

Based on cross-dated increment cores, yearly diameters of trees were reconstructed for 21 laurels (Cordia alliodora) growing in a natural secondary forest on Gigante Peninsula, Panama. From this sample of dominant-codominant trees, ages were 14–35 years with an average of 25 years. Growth typically slowed at 7 years old, indicating effects of...

Evidence of solar activity and El Niño signals in tree rings of Araucaria araucana and A. angustifolia in South America

NASA Astrophysics Data System (ADS)

Perone, A.; Lombardi, F.; Marchetti, M.; Tognetti, R.; Lasserre, B.

2016-10-01

Tree rings reveal climatic variations through years, but also the effect of solar activity in influencing the climate on a large scale. In order to investigate the role of solar cycles on climatic variability and to analyse their influences on tree growth, we focused on tree-ring chronologies of Araucaria angustifolia and Araucaria araucana in four study areas: Irati and Curitiba in Brazil, Caviahue in Chile, and Tolhuaca in Argentina. We obtained an average tree-ring chronology of 218, 117, 439, and 849 years for these areas, respectively. Particularly, the older chronologies also included the period of the Maunder and Dalton minima. To identify periodicities and trends observable in tree growth, the time series were analysed using spectral, wavelet and cross-wavelet techniques. Analysis based on the Multitaper method of annual growth rates identified 2 cycles with periodicities of 11 (Schwebe cycle) and 5.5 years (second harmonic of Schwebe cycle). In the Chilean and Argentinian sites, significant agreement between the time series of tree rings and the 11-year solar cycle was found during the periods of maximum solar activity. Results also showed oscillation with periods of 2-7 years, probably induced by local environmental variations, and possibly also related to the El-Niño events. Moreover, the Morlet complex wavelet analysis was applied to study the most relevant variability factors affecting tree-ring time series. Finally, we applied the cross-wavelet spectral analysis to evaluate the time lags between tree-ring and sunspot-number time series, as well as for the interaction between tree rings, the Southern Oscillation Index (SOI) and temperature and precipitation. Trees sampled in Chile and Argentina showed more evident responses of fluctuations in tree-ring time series to the variations of short and long periodicities in comparison with the Brazilian ones. These results provided new evidence on the solar activity-climate pattern-tree ring connections over centuries.

NEEDLE ANATOMY CHANGES WITH INCREASING TREE AGE IN DOUGLAS FIR

EPA Science Inventory

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

Lift-enhancement in the gliding paradise tree snake

NASA Astrophysics Data System (ADS)

Krishnan, Anush; Barba, Lorena A.

2012-11-01

The paradise tree snake is a good glider, despite having no wing-like appendages. This snake jumps from tree branches, flattens its body and adopts an S-shape, then glides while undulating laterally in the air. Previous experimental studies in wind and water tunnels showed that the lift of the snake cross-section can peak markedly at about 35° angle of attack, a surprising feature that hints at a lift-enhancing mechanism. Here, we report numerical simulations on the snake cross-section using an immersed boundary method, which also show the peak in lift above a certain Reynolds number threshold. Our visualizations reveal a change in the vortex shedding pattern at that angle of attack. We also study variants of the cross-section, removing the anatomical overhanging lips on the fore and aft, and observe that they have a large impact on the flow field. The best performance is in fact obtained with the anatomically correct shape of the snake.

Climate Change Threatens Coexistence within Communities of Mediterranean Forested Wetlands

PubMed Central

Di Paola, Arianna; Valentini, Riccardo; Paparella, Francesco

2012-01-01

The Mediterranean region is one of the hot spots of climate change. This study aims at understanding what are the conditions sustaining tree diversity in Mediterranean wet forests under future scenarios of altered hydrological regimes. The core of the work is a quantitative, dynamic model describing the coexistence of different Mediterranean tree species, typical of arid or semi-arid wetlands. Two kind of species, i.e. Hygrophilous (drought sensitive, flood resistant) and Non-hygrophilous (drought resistant, flood sensitive), are broadly defined according to the distinct adaptive strategies of trees against water stress of summer drought and winter flooding. We argue that at intermediate levels of water supply the dual role of water (resource and stress) results in the coexistence of the two kind of species. A bifurcation analysis allows us to assess the effects of climate change on the coexistence of the two species in order to highlight the impacts of predicted climate scenarios on tree diversity. Specifically, the model has been applied to Mediterranean coastal swamp forests of Central Italy located at Castelporziano Estate and Circeo National Park. Our results show that there are distinct rainfall thresholds beyond which stable coexistence becomes impossible. Regional climatic projections show that the lower rainfall threshold may be approached or crossed during the XXI century, calling for an urgent adaptation and mitigation response to prevent biodiversity losses. PMID:23077484

Specific gravity variation in robusta eucalyptus grown in Hawaii

Treesearch

Roger G. Skolmen

1972-01-01

The specific gravity (air-dry volume, ovendry weight) of Eucalyptus robusta wood was tested within and between trees from 10 stands. Mean specific gravity was 0.603, but the range in individual samples for 50 trees was 0.331 to 0.869, and was 0.357 to 0.755 within one cross section. A consistent increase was recorded in all trees from pith to cambium and from butt to...

Clinical allergy to hazelnut and peanut: identification of T cell cross-reactive allergens.

PubMed

Glaspole, Ian N; de Leon, Maria P; Prickett, Sara R; O'Hehir, Robyn E; Rolland, Jennifer M

2011-01-01

Peanut and tree nut allergies are life-threatening conditions for many affected individuals worldwide. Currently there is no cure. While co-allergy to peanut and tree nuts is a common clinical observation, and IgE cross-reactivity between peanut and tree nuts is reported, T cell cross-reactivity is poorly defined. Hazelnut-specific T cell lines were established using peripheral blood mononuclear cells from 5 subjects with co-allergy to hazelnut and peanut. These lines were stimulated with hazelnut and peanut extracts and purified major peanut allergens, Ara h 1 and Ara h 2. Proliferation was determined by (3)H-thymidine incorporation and secretion of key Th1 (IFN-γ) and Th2 (IL-5) cytokines analysed by ELISA. Hazelnut-specific T cell lines from all 5 subjects proliferated upon stimulation with both hazelnut and peanut extracts and for 4 subjects, to Ara h 1 and/or Ara h 2. Proliferating cells were mainly CD4+ T cells and produced both IL-5 and IFN-γ in response to hazelnut and peanut stimulation. Mitogenicity of extracts and allergens was excluded by their lack of stimulation of house dust mite-specific T cells. Our finding that hazelnut and peanut co-allergy is associated with cross-reactive T cell responses, driven partly by cross-reactivity to the major peanut allergens Ara h 1 and Ara h 2, points to future development of allergen immunotherapy by targeting cross-reactive T cells. Copyright © 2011 S. Karger AG, Basel.

Meta-transcriptomics indicates biotic cross-tolerance in willow trees cultivated on petroleum hydrocarbon contaminated soil.

PubMed

Gonzalez, Emmanuel; Brereton, Nicholas J B; Marleau, Julie; Guidi Nissim, Werther; Labrecque, Michel; Pitre, Frederic E; Joly, Simon

2015-10-12

High concentrations of petroleum hydrocarbon (PHC) pollution can be hazardous to human health and leave soils incapable of supporting agricultural crops. A cheap solution, which can help restore biodiversity and bring land back to productivity, is cultivation of high biomass yielding willow trees. However, the genetic mechanisms which allow these fast-growing trees to tolerate PHCs are as yet unclear. Salix purpurea 'Fish Creek' trees were pot-grown in soil from a former petroleum refinery, either lacking or enriched with C10-C50 PHCs. De novo assembled transcriptomes were compared between tree organs and impartially annotated without a priori constraint to any organism. Over 45% of differentially expressed genes originated from foreign organisms, the majority from the two-spotted spidermite, Tetranychus urticae. Over 99% of T. urticae transcripts were differentially expressed with greater abundance in non-contaminated trees. Plant transcripts involved in the polypropanoid pathway, including phenylalanine ammonia-lyase (PAL), had greater expression in contaminated trees whereas most resistance genes showed higher expression in non-contaminated trees. The impartial approach to annotation of the de novo transcriptomes, allowing for the possibility for multiple species identification, was essential for interpretation of the crop's response treatment. The meta-transcriptomic pattern of expression suggests a cross-tolerance mechanism whereby abiotic stress resistance systems provide improved biotic resistance. These findings highlight a valuable but complex biotic and abiotic stress response to real-world, multidimensional contamination which could, in part, help explain why crops such as willow can produce uniquely high biomass yields on challenging marginal land.

The Tree Worker's Manual.

ERIC Educational Resources Information Center

Smithyman, S. J.

This manual is designed to prepare students for entry-level positions as tree care professionals. Addressed in the individual chapters of the guide are the following topics: the tree service industry; clothing, eqiupment, and tools; tree workers; basic tree anatomy; techniques of pruning; procedures for climbing and working in the tree; aerial…

Protecting tree roots and subterranean infrastructure in urban areas by developing self-compacting flowable fills with root growth impeding properties

NASA Astrophysics Data System (ADS)

Felde, Vincent; Simon, Jana; Kimm-Friedenberg, Stefan; Peth, Stephan; Middendorf, Bernhard

2015-04-01

In urban areas, the installation of cables and disposal lines is still done by open building method. Here, a ditch is being excavated, pipes and lines are laid and subsequently it is filled with and covered by bulk material (e.g. sand or gravel), which is then compacted. Due to the often times limited space that the roots have in the ground and the better supply of water and oxygen in the poorly compacted bulk material, these refilled ditches are areas of preferential root growth of urban trees. The entangling of the pipes and supply lines by these roots leads to severe damage of the tree when maintenance work on the lines is carried out and roots have to be cut. In order to reduce this competition between urban trees and urban subterranean infrastructure, the development of a self-compacting flowable fill with root growth resistance is mandatory. Physico-chemical properties, such as a very high pH-value and a low cation-exchange-capacity, a low root-penetrability, a high packing density and a low porosity, with a poorly connected pore system that impedes gas and water exchange are the characteristic aspects of this flowable fills that could help avoid undesired root penetration into supply lines. The flowable fills are supposed to sheath pipes and lines void-free and without any tension, in order to restrain the root growth in these areas. Trees are of crucial importance for urban ecosystems and are comprising 3% of the total stock of trees in the Federal Republic of Germany, which is why it is fundamental to conserve them. This work therefore targets not only at enabling a balanced coexistence of urban trees and subterranean infrastructure, but also at avoiding costly re-opening of ditches, tree harming cutting of roots and time consuming maintenance work. Further positive side effects are reduced costs for network providers and local municipalities, as well as reduced noise and dust emissions for passersby and local residents. To guarantee the root growth restricting properties, the self-compacting fill has to have less porosity than the adjacent soil (40 - 60%). Theoretically a porosity of 30% is possible with a homogeneous compaction of sand. In urban areas, however, because of the limited spaces and crossing pipes, a mechanical and homogenous compacting is often impossible. Porosities of 60 to 70% are the result. Self-compacting flowable fills have a porosity of about 40% while the first optimized materials can even have a porosity of 28%. We present the first results of the hydro-mechanical properties of the different materials under development that highlight the influence of the mixture of the fills (i.e. maximal grain size) on the root growth impeding properties, while still ensuring mechanical workability of the material (in spite of the low porosity, strengths less than 0.8 N mm-² must be ensured at all times).

A Comparison Study of Classifier Algorithms for Cross-Person Physical Activity Recognition

PubMed Central

Saez, Yago; Baldominos, Alejandro; Isasi, Pedro

2016-01-01

Physical activity is widely known to be one of the key elements of a healthy life. The many benefits of physical activity described in the medical literature include weight loss and reductions in the risk factors for chronic diseases. With the recent advances in wearable devices, such as smartwatches or physical activity wristbands, motion tracking sensors are becoming pervasive, which has led to an impressive growth in the amount of physical activity data available and an increasing interest in recognizing which specific activity a user is performing. Moreover, big data and machine learning are now cross-fertilizing each other in an approach called “deep learning”, which consists of massive artificial neural networks able to detect complicated patterns from enormous amounts of input data to learn classification models. This work compares various state-of-the-art classification techniques for automatic cross-person activity recognition under different scenarios that vary widely in how much information is available for analysis. We have incorporated deep learning by using Google’s TensorFlow framework. The data used in this study were acquired from PAMAP2 (Physical Activity Monitoring in the Ageing Population), a publicly available dataset containing physical activity data. To perform cross-person prediction, we used the leave-one-subject-out (LOSO) cross-validation technique. When working with large training sets, the best classifiers obtain very high average accuracies (e.g., 96% using extra randomized trees). However, when the data volume is drastically reduced (where available data are only 0.001% of the continuous data), deep neural networks performed the best, achieving 60% in overall prediction accuracy. We found that even when working with only approximately 22.67% of the full dataset, we can statistically obtain the same results as when working with the full dataset. This finding enables the design of more energy-efficient devices and facilitates cold starts and big data processing of physical activity records. PMID:28042838

A Comparison Study of Classifier Algorithms for Cross-Person Physical Activity Recognition.

PubMed

Saez, Yago; Baldominos, Alejandro; Isasi, Pedro

2016-12-30

Physical activity is widely known to be one of the key elements of a healthy life. The many benefits of physical activity described in the medical literature include weight loss and reductions in the risk factors for chronic diseases. With the recent advances in wearable devices, such as smartwatches or physical activity wristbands, motion tracking sensors are becoming pervasive, which has led to an impressive growth in the amount of physical activity data available and an increasing interest in recognizing which specific activity a user is performing. Moreover, big data and machine learning are now cross-fertilizing each other in an approach called "deep learning", which consists of massive artificial neural networks able to detect complicated patterns from enormous amounts of input data to learn classification models. This work compares various state-of-the-art classification techniques for automatic cross-person activity recognition under different scenarios that vary widely in how much information is available for analysis. We have incorporated deep learning by using Google's TensorFlow framework. The data used in this study were acquired from PAMAP2 (Physical Activity Monitoring in the Ageing Population), a publicly available dataset containing physical activity data. To perform cross-person prediction, we used the leave-one-subject-out (LOSO) cross-validation technique. When working with large training sets, the best classifiers obtain very high average accuracies (e.g., 96% using extra randomized trees). However, when the data volume is drastically reduced (where available data are only 0.001% of the continuous data), deep neural networks performed the best, achieving 60% in overall prediction accuracy. We found that even when working with only approximately 22.67% of the full dataset, we can statistically obtain the same results as when working with the full dataset. This finding enables the design of more energy-efficient devices and facilitates cold starts and big data processing of physical activity records.

Survival and Early Growth of Selected Trees on Waste Water Application Sites

Treesearch

John H. Cooley

1978-01-01

The response of six tree species and three Populus hybrids to irrigation with oxidation pond effluent were compared. When weeds were intensively controlled, a P. deltoides x P. nigra cross responded best, but when weeds were less intensively controlled, P. canescens x P. tremuloides responded best.

Does water transport scale universally with tree size?

Treesearch

F.C. Meinzer; B.J. Bond; J.M. Warren; D.R. Woodruff

2005-01-01

1. We employed standardized measurement techniques and protocols to describe the size dependence of whole-tree water use and cross-sectional area of conducting xylem (sapwood) among several species of angiosperms and conifers. 2. The results were not inconsistent with previously proposed 314-power scaling of water transport with estimated above-...

Fuzzy tree automata and syntactic pattern recognition.

PubMed

Lee, E T

1982-04-01

An approach of representing patterns by trees and processing these trees by fuzzy tree automata is described. Fuzzy tree automata are defined and investigated. The results include that the class of fuzzy root-to-frontier recognizable ¿-trees is closed under intersection, union, and complementation. Thus, the class of fuzzy root-to-frontier recognizable ¿-trees forms a Boolean algebra. Fuzzy tree automata are applied to processing fuzzy tree representation of patterns based on syntactic pattern recognition. The grade of acceptance is defined and investigated. Quantitative measures of ``approximate isosceles triangle,'' ``approximate elongated isosceles triangle,'' ``approximate rectangle,'' and ``approximate cross'' are defined and used in the illustrative examples of this approach. By using these quantitative measures, a house, a house with high roof, and a church are also presented as illustrative examples. In addition, three fuzzy tree automata are constructed which have the capability of processing the fuzzy tree representations of ``fuzzy houses,'' ``houses with high roofs,'' and ``fuzzy churches,'' respectively. The results may have useful applications in pattern recognition, image processing, artificial intelligence, pattern database design and processing, image science, and pictorial information systems.

Following "the Roots" of Kratom (Mitragyna speciosa): The Evolution of an Enhancer from a Traditional Use to Increase Work and Productivity in Southeast Asia to a Recreational Psychoactive Drug in Western Countries.

PubMed

Cinosi, Eduardo; Martinotti, Giovanni; Simonato, Pierluigi; Singh, Darshan; Demetrovics, Zsolt; Roman-Urrestarazu, Andres; Bersani, Francesco Saverio; Vicknasingam, Balasingam; Piazzon, Giulia; Li, Jih-Heng; Yu, Wen-Jing; Kapitány-Fövény, Máté; Farkas, Judit; Di Giannantonio, Massimo; Corazza, Ornella

2015-01-01

The use of substances to enhance human abilities is a constant and cross-cultural feature in the evolution of humanity. Although much has changed over time, the availability on the Internet, often supported by misleading marketing strategies, has made their use even more likely and risky. This paper will explore the case of Mitragyna speciosa Korth. (kratom), a tropical tree used traditionally to combat fatigue and improve work productivity among farm populations in Southeast Asia, which has recently become popular as novel psychoactive substance in Western countries. Specifically, it (i) reviews the state of the art on kratom pharmacology and identification; (ii) provides a comprehensive overview of kratom use cross-culturally; (iii) explores the subjective experiences of users; (iv) identifies potential risks and side-effects related to its consumption. Finally, it concludes that the use of kratom is not negligible, especially for self-medication, and more clinical, pharmacological, and socioanthropological studies as well as a better international collaboration are needed to tackle this marginally explored phenomenon.

An Ecological Analysis of Environmental Correlates of Active Commuting in Urban U.S.

PubMed Central

Fan, Jessie X.; Wen, Ming; Kowaleski-Jones, Lori

2014-01-01

We conduct a cross-sectional ecological analysis to examine environmental correlates of active commuting in 39,660 urban tracts using data from the 2010 Census, 2007-2011 American Community Survey, and other sources. The five-year average (2007-2011) prevalence is 3.05% for walking, 0.63% for biking, and 7.28% for public transportation to work, with higher prevalence for all modes in lower-income tracts. Environmental factors account for more variances in public transportation to work but economic and demographic factors account for more variances in walking and biking to work. Population density, median housing age, street connectivity, tree canopy, distance to parks, air quality, and county sprawl index are associated with active commuting, but the association can vary in size and direction for different transportation mode and for higher-income and lower-income tracts. PMID:25460907

An ecological analysis of environmental correlates of active commuting in urban U.S.

PubMed

Fan, Jessie X; Wen, Ming; Kowaleski-Jones, Lori

2014-11-01

We conduct a cross-sectional ecological analysis to examine environmental correlates of active commuting in 39,660 urban tracts using data from the 2010 Census, 2007-2011 American Community Survey, and other sources. The five-year average (2007-2011) prevalence is 3.05% for walking, 0.63% for biking, and 7.28% for public transportation to work, with higher prevalence for all modes in lower-income tracts. Environmental factors account for more variances in public transportation to work but economic and demographic factors account for more variances in walking and biking to work. Population density, median housing age, street connectivity, tree canopy, distance to parks, air quality, and county sprawl index are associated with active commuting, but the association can vary in size and direction for different transportation mode and for higher-income and lower-income tracts. Copyright © 2014 Elsevier Ltd. All rights reserved.

Interactions across spatial scales among forest dieback, fire, and erosion in northern New Mexico landscapes

USGS Publications Warehouse

Allen, Craig D.

2007-01-01

Ecosystem patterns and disturbance processes at one spatial scale often interact with processes at another scale, and the result of such cross-scale interactions can be nonlinear dynamics with thresholds. Examples of cross-scale pattern-process relationships and interactions among forest dieback, fire, and erosion are illustrated from northern New Mexico (USA) landscapes, where long-term studies have recently documented all of these disturbance processes. For example, environmental stress, operating on individual trees, can cause tree death that is amplified by insect mortality agents to propagate to patch and then landscape or even regional-scale forest dieback. Severe drought and unusual warmth in the southwestern USA since the late 1990s apparently exceeded species-specific physiological thresholds for multiple tree species, resulting in substantial vegetation mortality across millions of hectares of woodlands and forests in recent years. Predictions of forest dieback across spatial scales are constrained by uncertainties associated with: limited knowledge of species-specific physiological thresholds; individual and site-specific variation in these mortality thresholds; and positive feedback loops between rapidly-responding insect herbivore populations and their stressed plant hosts, sometimes resulting in nonlinear “pest” outbreak dynamics. Fire behavior also exhibits nonlinearities across spatial scales, illustrated by changes in historic fire regimes where patch-scale grazing disturbance led to regional-scale collapse of surface fire activity and subsequent recent increases in the scale of extreme fire events in New Mexico. Vegetation dieback interacts with fire activity by modifying fuel amounts and configurations at multiple spatial scales. Runoff and erosion processes are also subject to scale-dependent threshold behaviors, exemplified by ecohydrological work in semiarid New Mexico watersheds showing how declines in ground surface cover lead to non-linear increases in bare patch connectivity and thereby accelerated runoff and erosion at hillslope and watershed scales. Vegetation dieback, grazing, and fire can change land surface properties and cross-scale hydrologic connectivities, directly altering ecohydrological patterns of runoff and erosion. The interactions among disturbance processes across spatial scales can be key drivers in ecosystem dynamics, as illustrated by these studies of recent landscape changes in northern New Mexico. To better anticipate and mitigate accelerating human impacts to the planetary ecosystem at all spatial scales, improvements are needed in our conceptual and quantitative understanding of cross-scale interactions among disturbance processes.

Decision Tree Phytoremediation

DTIC Science & Technology

1999-12-01

aromatic hydrocarbons, and landfill leachates . Phytoremediation has been used for point and nonpoint source hazardous waste control. 1.2 Types of... Phytoremediation Prepared by Interstate Technology and Regulatory Cooperation Work Group Phytoremediation Work Team December 1999 Decision Tree...1999 2. REPORT TYPE N/A 3. DATES COVERED - 4. TITLE AND SUBTITLE Phytoremediation Decision Tree 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c

A method for determining fire history in coniferous forests in the Mountain West

Treesearch

Stephen F. Arno; Kathy M. Sneck

1977-01-01

Describes a method for determining historic fire frequency, intensity, and size from cross sections collected from fire-scarred trees and tree age classes determined through increment borings. Tells how to interpret the influence of fire in stand composition and structure and how to identify effects of modern fire suppression.

Hybridizing pines with diluted pollen

Treesearch

Robert Z. Callaham

1967-01-01

Diluted pollens would have many uses by the tree breeder. Dilutions would be particularly advantageous in making many controlled pollinations with a limited amount of pollen. They also would be useful in artificial mass pollinations of orchards or single trees. Diluted pollens might help overcome troublesome genetic barriers to crossing. Feasibility o,f using diluted...

Multiple kernel learning in protein-protein interaction extraction from biomedical literature.

PubMed

Yang, Zhihao; Tang, Nan; Zhang, Xiao; Lin, Hongfei; Li, Yanpeng; Yang, Zhiwei

2011-03-01

Knowledge about protein-protein interactions (PPIs) unveils the molecular mechanisms of biological processes. The volume and content of published biomedical literature on protein interactions is expanding rapidly, making it increasingly difficult for interaction database administrators, responsible for content input and maintenance to detect and manually update protein interaction information. The objective of this work is to develop an effective approach to automatic extraction of PPI information from biomedical literature. We present a weighted multiple kernel learning-based approach for automatic PPI extraction from biomedical literature. The approach combines the following kernels: feature-based, tree, graph and part-of-speech (POS) path. In particular, we extend the shortest path-enclosed tree (SPT) and dependency path tree to capture richer contextual information. Our experimental results show that the combination of SPT and dependency path tree extensions contributes to the improvement of performance by almost 0.7 percentage units in F-score and 2 percentage units in area under the receiver operating characteristics curve (AUC). Combining two or more appropriately weighed individual will further improve the performance. Both on the individual corpus and cross-corpus evaluation our combined kernel can achieve state-of-the-art performance with respect to comparable evaluations, with 64.41% F-score and 88.46% AUC on the AImed corpus. As different kernels calculate the similarity between two sentences from different aspects. Our combined kernel can reduce the risk of missing important features. More specifically, we use a weighted linear combination of individual kernels instead of assigning the same weight to each individual kernel, thus allowing the introduction of each kernel to incrementally contribute to the performance improvement. In addition, SPT and dependency path tree extensions can improve the performance by including richer context information. Copyright © 2010 Elsevier B.V. All rights reserved.

PIPE: a protein–protein interaction passage extraction module for BioCreative challenge

PubMed Central

Chu, Chun-Han; Su, Yu-Chen; Chen, Chien Chin; Hsu, Wen-Lian

2016-01-01

Identifying the interactions between proteins mentioned in biomedical literatures is one of the frequently discussed topics of text mining in the life science field. In this article, we propose PIPE, an interaction pattern generation module used in the Collaborative Biocurator Assistant Task at BioCreative V (http://www.biocreative.org/) to capture frequent protein-protein interaction (PPI) patterns within text. We also present an interaction pattern tree (IPT) kernel method that integrates the PPI patterns with convolution tree kernel (CTK) to extract PPIs. Methods were evaluated on LLL, IEPA, HPRD50, AIMed and BioInfer corpora using cross-validation, cross-learning and cross-corpus evaluation. Empirical evaluations demonstrate that our method is effective and outperforms several well-known PPI extraction methods. Database URL: PMID:27524807

Progress Towards a Neutral Current $$\\pi^0$$ Cross Section Analysis in the NOvA Near Detector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bowles, Reed; Paley, Jonathan

The NOvA neutrino experiment is attempting to measure properties of neutrinos in order to figure out information about the universe. To detect the signal neutrino interactions, we must determine methods to identify and isolate background events. Research focused on a specific background interaction called a single prong neutral currentmore » $$\\pi^0$$ interaction. To do this, a basic cuts based analysis was performed, followed by feeding data into a multi-variate analysis package using a boosted decision tree (BDT) algorithm. Using the BDT, a a new variable was generated which separates signal and background very efficiently. Further work must still be done in order to continue improving the performance of the BDT. This research is valuable to the field of studying neutrino cross sections as it is a background which will always be present in this type of analysis.« less

High-Throughput 3-D Monitoring of Agricultural-Tree Plantations with Unmanned Aerial Vehicle (UAV) Technology

PubMed Central

Torres-Sánchez, Jorge; López-Granados, Francisca; Serrano, Nicolás; Arquero, Octavio; Peña, José M.

2015-01-01

The geometric features of agricultural trees such as canopy area, tree height and crown volume provide useful information about plantation status and crop production. However, these variables are mostly estimated after a time-consuming and hard field work and applying equations that treat the trees as geometric solids, which produce inconsistent results. As an alternative, this work presents an innovative procedure for computing the 3-dimensional geometric features of individual trees and tree-rows by applying two consecutive phases: 1) generation of Digital Surface Models with Unmanned Aerial Vehicle (UAV) technology and 2) use of object-based image analysis techniques. Our UAV-based procedure produced successful results both in single-tree and in tree-row plantations, reporting up to 97% accuracy on area quantification and minimal deviations compared to in-field estimations of tree heights and crown volumes. The maps generated could be used to understand the linkages between tree grown and field-related factors or to optimize crop management operations in the context of precision agriculture with relevant agro-environmental implications. PMID:26107174

High-Throughput 3-D Monitoring of Agricultural-Tree Plantations with Unmanned Aerial Vehicle (UAV) Technology.

PubMed

Torres-Sánchez, Jorge; López-Granados, Francisca; Serrano, Nicolás; Arquero, Octavio; Peña, José M

2015-01-01

The geometric features of agricultural trees such as canopy area, tree height and crown volume provide useful information about plantation status and crop production. However, these variables are mostly estimated after a time-consuming and hard field work and applying equations that treat the trees as geometric solids, which produce inconsistent results. As an alternative, this work presents an innovative procedure for computing the 3-dimensional geometric features of individual trees and tree-rows by applying two consecutive phases: 1) generation of Digital Surface Models with Unmanned Aerial Vehicle (UAV) technology and 2) use of object-based image analysis techniques. Our UAV-based procedure produced successful results both in single-tree and in tree-row plantations, reporting up to 97% accuracy on area quantification and minimal deviations compared to in-field estimations of tree heights and crown volumes. The maps generated could be used to understand the linkages between tree grown and field-related factors or to optimize crop management operations in the context of precision agriculture with relevant agro-environmental implications.

Spatial cross-correlation of undisturbed, natural shortleaf pine stands in northern Georgia

Treesearch

Robin M. Reich; Raymond L. Czaplewski; William A. Bechtold

1994-01-01

In this study a cross-correlation statistic is used to analyse the spatial relationship among stand characteristics of natural, undisturbed shortleaf pine stands sampled during 1961-72 and 1972-82 in northern Georgia. Stand characteristics included stand age, site index, tree density, hardwood competition, and mortality. In each time period, the spatial cross-...

UV-laser-based microscopic dissection of tree rings - a novel sampling tool for δ(13) C and δ(18) O studies.

PubMed

Schollaen, Karina; Heinrich, Ingo; Helle, Gerhard

2014-02-01

UV-laser-based microscopic systems were utilized to dissect and sample organic tissue for stable isotope measurements from thin wood cross-sections. We tested UV-laser-based microscopic tissue dissection in practice for high-resolution isotopic analyses (δ(13) C/δ(18) O) on thin cross-sections from different tree species. The method allows serial isolation of tissue of any shape and from millimetre down to micrometre scales. On-screen pre-defined areas of interest were automatically dissected and collected for mass spectrometric analysis. Three examples of high-resolution isotopic analyses revealed that: in comparison to δ(13) C of xylem cells, woody ray parenchyma of deciduous trees have the same year-to-year variability, but reveal offsets that are opposite in sign depending on whether wholewood or cellulose is considered; high-resolution tree-ring δ(18) O profiles of Indonesian teak reflect monsoonal rainfall patterns and are sensitive to rainfall extremes caused by ENSO; and seasonal moisture signals in intra-tree-ring δ(18) O of white pine are weighted by nonlinear intra-annual growth dynamics. The applications demonstrate that the use of UV-laser-based microscopic dissection allows for sampling plant tissue at ultrahigh resolution and unprecedented precision. This new technique facilitates sampling for stable isotope analysis of anatomical plant traits like combined tree eco-physiological, wood anatomical and dendroclimatological studies. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

Tree Tensor Network State with Variable Tensor Order: An Efficient Multireference Method for Strongly Correlated Systems

PubMed Central

2015-01-01

We study the tree-tensor-network-state (TTNS) method with variable tensor orders for quantum chemistry. TTNS is a variational method to efficiently approximate complete active space (CAS) configuration interaction (CI) wave functions in a tensor product form. TTNS can be considered as a higher order generalization of the matrix product state (MPS) method. The MPS wave function is formulated as products of matrices in a multiparticle basis spanning a truncated Hilbert space of the original CAS-CI problem. These matrices belong to active orbitals organized in a one-dimensional array, while tensors in TTNS are defined upon a tree-like arrangement of the same orbitals. The tree-structure is advantageous since the distance between two arbitrary orbitals in the tree scales only logarithmically with the number of orbitals N, whereas the scaling is linear in the MPS array. It is found to be beneficial from the computational costs point of view to keep strongly correlated orbitals in close vicinity in both arrangements; therefore, the TTNS ansatz is better suited for multireference problems with numerous highly correlated orbitals. To exploit the advantages of TTNS a novel algorithm is designed to optimize the tree tensor network topology based on quantum information theory and entanglement. The superior performance of the TTNS method is illustrated on the ionic-neutral avoided crossing of LiF. It is also shown that the avoided crossing of LiF can be localized using only ground state properties, namely one-orbital entanglement. PMID:25844072

Children's Ideas about the Internal Structure of Trees: Cross-Age Studies

ERIC Educational Resources Information Center

Rybska, Eliza; Tunnicliffe, Sue Dale; Sajkowska, Zofia Anna

2017-01-01

Trees are important to the environment owing to their ecological services. However, many aspects of their form and function are poorly understood by the public. From their earliest years, children have an elementary knowledge about plants which they gain from their everyday observations, their parents and other people and from their kindergarten…

Wood Products by Species and Quality in Upland Forests

Treesearch

David W. Patterson

2004-01-01

Products that can be produced from an upland forest depend on the species and quality of the trees present. Quality depends on growth rate and tree form. These variables are discussed as well as the products that can be produced such as veneer and plywood, grade lumber, handle stock, pallet stock, cross ties, and industrial lumber.

An experimental evaluation of fire history reconstruction using dendrochronology in white oak (Quercus alba)

Treesearch

Ryan W. McEwan; Todd F. Hutchinson; Robert D. Ford; Brian C. McCarthy

2007-01-01

Dendrochronological analysis of fire scars on tree cross sections has been critically important for understanding historical fire regimes and has influenced forest management practices. Despite its value as a tool for understanding historical ecosystems, tree-ring-based fire history reconstruction has rarely been experimentally evaluated. To examine the efficacy of...

Genetic linkage maps of white birches (Betula platyphylla Suk. and B. pendula Roth) based on RAPD and AFLP markers

USDA-ARS?s Scientific Manuscript database

Genetic linkage maps in plants are usually constructed using segregating populations obtained from crosses between two inbred lines such as rice, maize, or soybean. Such populations are generally not available for forest trees because of time constraints. But tree species have the property of outcro...

Engineering design for pedestrian safety at highway-rail grade crossings

DOT National Transportation Integrated Search

2016-07-01

A number of pedestrian treatments at railroad grade crossings have been developed and are used throughout the United States. The decision of when to use these treatments is generally a matter of best practices, using a decision tree, or conducting a ...

Inferring patterns in mitochondrial DNA sequences through hypercube independent spanning trees.

PubMed

Silva, Eduardo Sant Ana da; Pedrini, Helio

2016-03-01

Given a graph G, a set of spanning trees rooted at a vertex r of G is said vertex/edge independent if, for each vertex v of G, v≠r, the paths of r to v in any pair of trees are vertex/edge disjoint. Independent spanning trees (ISTs) provide a number of advantages in data broadcasting due to their fault tolerant properties. For this reason, some studies have addressed the issue by providing mechanisms for constructing independent spanning trees efficiently. In this work, we investigate how to construct independent spanning trees on hypercubes, which are generated based upon spanning binomial trees, and how to use them to predict mitochondrial DNA sequence parts through paths on the hypercube. The prediction works both for inferring mitochondrial DNA sequences comprised of six bases as well as infer anomalies that probably should not belong to the mitochondrial DNA standard. Copyright © 2016 Elsevier Ltd. All rights reserved.

Additivity in tree biomass components of Pyrenean oak (Quercus pyrenaica Willd.)

Treesearch

Joao P. Carvalho; Bernard R. Parresol

2003-01-01

In tree biomass estimations, it is important to consider the property of additivity, i.e., the total tree biomass should equal the sum of the components. This work presents functions that allow estimation of the stem and crown dry weight components of Pyrenean oak (Quercus pyrenaica Willd.) trees. A procedure that considers additivity of tree biomass...

Modifying Taper-Derived Merchantable Height Estimates to Account for Tree Characteristics

Treesearch

James A. Westfall

2006-01-01

The U.S. Department of Agriculture Forest Service Northeastern Forest Inventory and Analysis program (NE-FIA) is developing regionwide tree-taper equations. Unlike most previous work on modeling tree form, this effort necessarily includes a wide array of tree species. For some species, branching patterns can produce undesirable tree form that reduces the merchantable...

A universal hybrid decision tree classifier design for human activity classification.

PubMed

Chien, Chieh; Pottie, Gregory J

2012-01-01

A system that reliably classifies daily life activities can contribute to more effective and economical treatments for patients with chronic conditions or undergoing rehabilitative therapy. We propose a universal hybrid decision tree classifier for this purpose. The tree classifier can flexibly implement different decision rules at its internal nodes, and can be adapted from a population-based model when supplemented by training data for individuals. The system was tested using seven subjects each monitored by 14 triaxial accelerometers. Each subject performed fourteen different activities typical of daily life. Using leave-one-out cross validation, our decision tree produced average classification accuracies of 89.9%. In contrast, the MATLAB personalized tree classifiers using Gini's diversity index as the split criterion followed by optimally tuning the thresholds for each subject yielded 69.2%.

Production and analysis of recombinant tree nut allergens.

PubMed

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

2014-03-01

Allergic reactions to tree nuts are a growing global concern as the number of affected individuals continues to rise. Unlike some food allergies, tree nuts can cause severe reactions that persist throughout life. The tree nuts discussed in this review include those most commonly responsible for allergic reactions: cashew, almond, hazelnut, walnut, pecan, Brazil nut, pistachio, and chestnut. The native allergenic proteins derived from tree nuts are frequently difficult to isolate and purify and may not be adequately represented in aqueous nut protein extracts. Consequently, defined recombinant allergens have become useful reagents in a variety of immunoassays aimed at the diagnosis of tree nut allergy, assessing cross-reactivity between various nuts and other seeds, mapping of IgE binding epitopes, and analyzing the effects of the food matrix, food processing, and gastric digestion on allergenicity. This review describes the approaches that can be used for the production of recombinant tree nut allergens and addresses key issues associated with their production and downstream applications. Copyright © 2013 Elsevier Inc. All rights reserved.

[Wood transformation in dead-standing trees in the forest-tundra of Central Siberia].

PubMed

Mukhortova, L V; Kirdianov, A V; Myglan, V S; Guggenberger, G

2009-01-01

Changes in the composition of wood organic matter in dead-standing spruce and larch trees depending on the period after their death have been studied in the north of Central Siberia. The period after tree death has been estimated by means of cross-dating. The results show that changes in the composition of wood organic matter in 63% of cases are contingent on tree species. Wood decomposition in dead-standing trees is accompanied by an increase in the contents of alkali-soluble organic compounds. Lignin oxidation in larch begins approximately 80 years after tree death, whereas its transformation in spruce begins not earlier than after 100 years. In the forest-tundra of Central Siberia, the rate of wood organic matter transformation in dead-standing trees is one to two orders of magnitude lower than in fallen wood, which accounts for their role as a long-term store of carbon and mineral elements in these ecosystems.

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

NASA Astrophysics Data System (ADS)

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

2018-03-01

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

Effects of sample survey design on the accuracy of classification tree models in species distribution models

USGS Publications Warehouse

Edwards, T.C.; Cutler, D.R.; Zimmermann, N.E.; Geiser, L.; Moisen, Gretchen G.

2006-01-01

We evaluated the effects of probabilistic (hereafter DESIGN) and non-probabilistic (PURPOSIVE) sample surveys on resultant classification tree models for predicting the presence of four lichen species in the Pacific Northwest, USA. Models derived from both survey forms were assessed using an independent data set (EVALUATION). Measures of accuracy as gauged by resubstitution rates were similar for each lichen species irrespective of the underlying sample survey form. Cross-validation estimates of prediction accuracies were lower than resubstitution accuracies for all species and both design types, and in all cases were closer to the true prediction accuracies based on the EVALUATION data set. We argue that greater emphasis should be placed on calculating and reporting cross-validation accuracy rates rather than simple resubstitution accuracy rates. Evaluation of the DESIGN and PURPOSIVE tree models on the EVALUATION data set shows significantly lower prediction accuracy for the PURPOSIVE tree models relative to the DESIGN models, indicating that non-probabilistic sample surveys may generate models with limited predictive capability. These differences were consistent across all four lichen species, with 11 of the 12 possible species and sample survey type comparisons having significantly lower accuracy rates. Some differences in accuracy were as large as 50%. The classification tree structures also differed considerably both among and within the modelled species, depending on the sample survey form. Overlap in the predictor variables selected by the DESIGN and PURPOSIVE tree models ranged from only 20% to 38%, indicating the classification trees fit the two evaluated survey forms on different sets of predictor variables. The magnitude of these differences in predictor variables throws doubt on ecological interpretation derived from prediction models based on non-probabilistic sample surveys. ?? 2006 Elsevier B.V. All rights reserved.

Research frontiers in drought-induced tree mortality: Crossing scales and disciplines

DOE PAGES

Hartmann, Henrik; Adams, Henry D.; Anderegg, William R. L.; ...

2015-01-12

Sudden and widespread forest die-back and die-off (e.g., Huang & Anderegg, 2012) and increased mortality rates (e.g., Peng et al., 2011) in many forest ecosystems across the globe have been linked to drought and elevated temperatures (Allen et al., 2010, Fig. 1). Furthermore, these observations have caused a focus on the physiological mechanisms of drought-induced tree mortality (e.g. McDowell et al., 2008) and many studies, both observational and manipulative, have been carried out to explain tree death during drought from a physiological perspective.

Using tree diversity to compare phylogenetic heuristics.

PubMed

Sul, Seung-Jin; Matthews, Suzanne; Williams, Tiffani L

2009-04-29

Evolutionary trees are family trees that represent the relationships between a group of organisms. Phylogenetic heuristics are used to search stochastically for the best-scoring trees in tree space. Given that better tree scores are believed to be better approximations of the true phylogeny, traditional evaluation techniques have used tree scores to determine the heuristics that find the best scores in the fastest time. We develop new techniques to evaluate phylogenetic heuristics based on both tree scores and topologies to compare Pauprat and Rec-I-DCM3, two popular Maximum Parsimony search algorithms. Our results show that although Pauprat and Rec-I-DCM3 find the trees with the same best scores, topologically these trees are quite different. Furthermore, the Rec-I-DCM3 trees cluster distinctly from the Pauprat trees. In addition to our heatmap visualizations of using parsimony scores and the Robinson-Foulds distance to compare best-scoring trees found by the two heuristics, we also develop entropy-based methods to show the diversity of the trees found. Overall, Pauprat identifies more diverse trees than Rec-I-DCM3. Overall, our work shows that there is value to comparing heuristics beyond the parsimony scores that they find. Pauprat is a slower heuristic than Rec-I-DCM3. However, our work shows that there is tremendous value in using Pauprat to reconstruct trees-especially since it finds identical scoring but topologically distinct trees. Hence, instead of discounting Pauprat, effort should go in improving its implementation. Ultimately, improved performance measures lead to better phylogenetic heuristics and will result in better approximations of the true evolutionary history of the organisms of interest.

Resistance is not futile: The response of hardwoods to fire-caused wounding

Treesearch

Elaine Kennedy Sutherland; Kevin Smith

2000-01-01

Fires wound trees; but not all of them, and not always. Specific fire behavior and differences among tree species and individual trees produce variable patterns of wounding and wound response. Our work focuses on the relationships between fire behavior and tree biology to better understand how hardwood trees resist injury to the lower stem and either survive or succumb...

Summary of tree-breeding experiments by The Northeastern Forest Experiment Station 1947-1950

Treesearch

Jonathan W. Wright

1953-01-01

The tree-breeding work of the Northeastern Forest Experiment Station has its roots in a project started in 1924 by the Oxford Paper Company of Rumford, Maine, to develop fast-growing poplars that would be suitable for pulpwood. The initial tree-breeding work in this project was done by A. B. Stout and Ernst J. Schreiner, most of it at the New York Botanical Garden and...

Observation and identification of wood decay fungi from the heartwood of peach tree limbs in central Georgia, USA

USDA-ARS?s Scientific Manuscript database

Peach tree health, longevity, and limb strength can be affected by wood decay fungi, but the extent of the colonization and their identities have not been characterized in Georgia, the United States of America. In an incubation experiment, dense white fungal mycelium grew on the cross-cut faces of a...

Deep sequencing of viral small-RNAs of citrus tristeza virus (CTV) reveals genomic differences between two Italian isolates of CTV

USDA-ARS?s Scientific Manuscript database

A recent Citrus tristeza virus (CTV) epidemic of quick decline (QD) killed many sweet orange trees grafted on sour orange rootstock in Sicily but left some asymptomatic trees in the same field. Recent reports indicated cross-protection involves exclusion of a severe CTV strain by a mild strain of th...

Method of center localization for objects containing concentric arcs

NASA Astrophysics Data System (ADS)

Kuznetsova, Elena G.; Shvets, Evgeny A.; Nikolaev, Dmitry P.

2015-02-01

This paper proposes a method for automatic center location of objects containing concentric arcs. The method utilizes structure tensor analysis and voting scheme optimized with Fast Hough Transform. Two applications of the proposed method are considered: (i) wheel tracking in video-based system for automatic vehicle classification and (ii) tree growth rings analysis on a tree cross cut image.

A history of tree planting in West Virginia

Treesearch

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...

Examination of the Arborsonic Decay Detector for Detecting Bacterial Wetwood in Red Oaks

Treesearch

Zicai Xu; Theodor D. Leininger; James G. Williams; Frank H. Tainter

2000-01-01

The Arborsonic Decay Detector (ADD; Fujikura Europe Limited, Wiltshire, England) was used to measure the time it took an ultrasound wave to cross 280 diameters in red oak trees with varying degrees of bacterial wetwood or heartwood decay. Linear regressions derived from the ADD readings of trees in Mississippi and South Carolina with wetwood and heartwood decay...

A window of opportunity for climate-change adaptation: Easing tree mortality by reducing forest basal area

USGS Publications Warehouse

Bradford, John B.; Bell, David M.

2017-01-01

Increasing aridity as a result of climate change is expected to exacerbate tree mortality. Reducing forest basal area – the cross-sectional area of tree stems within a given ground area – can decrease tree competition, which may reduce drought-induced tree mortality. However, neither the magnitude of expected mortality increases, nor the potential effectiveness of basal area reduction, has been quantified in dryland forests such as those of the drought-prone Southwest US. We used thousands of repeatedly measured forest plots to show that unusually warm and dry conditions are related to high tree mortality rates and that mortality is positively related to basal area. Those relationships suggest that while increasing high temperature extremes forecasted by climate models may lead to elevated tree mortality during the 21st century, future tree mortality might be partly ameliorated by reducing stand basal area. This adaptive forest management strategy may provide a window of opportunity for forest managers and policy makers to guide forest transitions to species and/or genotypes more suited to future climates.

Section-Based Tree Species Identification Using Airborne LIDAR Point Cloud

NASA Astrophysics Data System (ADS)

Yao, C.; Zhang, X.; Liu, H.

2017-09-01

The application of LiDAR data in forestry initially focused on mapping forest community, particularly and primarily intended for largescale forest management and planning. Then with the smaller footprint and higher sampling density LiDAR data available, detecting individual tree overstory, estimating crowns parameters and identifying tree species are demonstrated practicable. This paper proposes a section-based protocol of tree species identification taking palm tree as an example. Section-based method is to detect objects through certain profile among different direction, basically along X-axis or Y-axis. And this method improve the utilization of spatial information to generate accurate results. Firstly, separate the tree points from manmade-object points by decision-tree-based rules, and create Crown Height Mode (CHM) by subtracting the Digital Terrain Model (DTM) from the digital surface model (DSM). Then calculate and extract key points to locate individual trees, thus estimate specific tree parameters related to species information, such as crown height, crown radius, and cross point etc. Finally, with parameters we are able to identify certain tree species. Comparing to species information measured on ground, the portion correctly identified trees on all plots could reach up to 90.65 %. The identification result in this research demonstrate the ability to distinguish palm tree using LiDAR point cloud. Furthermore, with more prior knowledge, section-based method enable the process to classify trees into different classes.

Decision tree and ensemble learning algorithms with their applications in bioinformatics.

PubMed

Che, Dongsheng; Liu, Qi; Rasheed, Khaled; Tao, Xiuping

2011-01-01

Machine learning approaches have wide applications in bioinformatics, and decision tree is one of the successful approaches applied in this field. In this chapter, we briefly review decision tree and related ensemble algorithms and show the successful applications of such approaches on solving biological problems. We hope that by learning the algorithms of decision trees and ensemble classifiers, biologists can get the basic ideas of how machine learning algorithms work. On the other hand, by being exposed to the applications of decision trees and ensemble algorithms in bioinformatics, computer scientists can get better ideas of which bioinformatics topics they may work on in their future research directions. We aim to provide a platform to bridge the gap between biologists and computer scientists.

Following “the Roots” of Kratom (Mitragyna speciosa): The Evolution of an Enhancer from a Traditional Use to Increase Work and Productivity in Southeast Asia to a Recreational Psychoactive Drug in Western Countries

PubMed Central

Cinosi, Eduardo; Martinotti, Giovanni; Simonato, Pierluigi; Singh, Darshan; Demetrovics, Zsolt; Roman-Urrestarazu, Andres; Bersani, Francesco Saverio; Vicknasingam, Balasingam; Piazzon, Giulia; Li, Jih-Heng; Yu, Wen-Jing; Kapitány-Fövény, Máté; Farkas, Judit; Di Giannantonio, Massimo; Corazza, Ornella

2015-01-01

The use of substances to enhance human abilities is a constant and cross-cultural feature in the evolution of humanity. Although much has changed over time, the availability on the Internet, often supported by misleading marketing strategies, has made their use even more likely and risky. This paper will explore the case of Mitragyna speciosa Korth. (kratom), a tropical tree used traditionally to combat fatigue and improve work productivity among farm populations in Southeast Asia, which has recently become popular as novel psychoactive substance in Western countries. Specifically, it (i) reviews the state of the art on kratom pharmacology and identification; (ii) provides a comprehensive overview of kratom use cross-culturally; (iii) explores the subjective experiences of users; (iv) identifies potential risks and side-effects related to its consumption. Finally, it concludes that the use of kratom is not negligible, especially for self-medication, and more clinical, pharmacological, and socioanthropological studies as well as a better international collaboration are needed to tackle this marginally explored phenomenon. PMID:26640804

Growth of ponderosa pine by keen tree class.

Treesearch

Philip A. Briegleb

1943-01-01

Every forester who works in the ponderosa pine woods is impressed by the tremendous range in size, quality, age, and thrift of the trees found in the virgin forest. So great is this variation from tree to tree that stand averages mean little to the timber marker trying to select trees of high value and insect risk for cutting, and at the same time reserve for future...

Cooperative test plots produce some promising Chinese and hybrid chestnut trees

Treesearch

Jesse D. Diller; Russell B. Clapper; Richard A. Jaynes

1964-01-01

In attempts to find a chestnut tree that is resistant to the blight fungus Endothia parasitica, Asiatic chestnuts have been imported and grown in this country, and tree breeders have worked to produce hybrid trees that might be suitable substitutes for the blight-susceptible American chestnut, Castanea dentate, in timber and nut...

Inheritance in a Diallel Crossing Experiment with Longleaf Pine

Treesearch

E. B. Snyder; Gene Namkoong

1978-01-01

Seven-year-old progeny from crosses among 13 randomly selected parent trees provided genetic information on 51 growth, form, foliage, branch, bud, and pest resistance traits. Presented are he&abilities, phenotypic and genotypic variances, covariances, General Combining Ability (GCA), Specific Combining Ability (SCA), and environmental. correlations for all measured...

Parental GCA testing: how many crosses per parent?

Treesearch

G.R. Johnson

1998-01-01

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

Automatic identification of vessel crossovers in retinal images

NASA Astrophysics Data System (ADS)

Sánchez, L.; Barreira, N.; Penedo, M. G.; Cancela, B.

2015-02-01

Crossovers and bifurcations are interest points of the retinal vascular tree useful to diagnose diseases. Specifically, detecting these interest points and identifying which of them are crossings will give us the opportunity to search for arteriovenous nicking, this is, an alteration of the vessel tree where an artery is crossed by a vein and the former compresses the later. These formations are a clear indicative of hypertension, among other medical problems. There are several studies that have attempted to define an accurate and reliable method to detect and classify these relevant points. In this article, we propose a new method to identify crossovers. Our approach is based on segmenting the vascular tree and analyzing the surrounding area of each interest point. The minimal path between vessel points in this area is computed in order to identify the connected vessel segments and, as a result, to distinguish between bifurcations and crossovers. Our method was tested using retinographies from public databases DRIVE and VICAVR, obtaining an accuracy of 90%.

Phenotypic variation among trees in a population of a Pistacia atlantica X P. integerrima cross sold as UCB-1 rootstock for grafting P. vera (pistachio) cultivars

USDA-ARS?s Scientific Manuscript database

UCB-1 is widely used in California as a pistachio rootstock because of its Verticillium resistance, salt and cold tolerance, and vigor. It can grow in most locations in California. However, significant variation exists in the phenotypic performance of trees grafted to seedling UCB-1 rootstocks. In J...

Assessing College Student Interest in Math and/or Computer Science in a Cross-National Sample Using Classification and Regression Trees

ERIC Educational Resources Information Center

Kitsantas, Anastasia; Kitsantas, Panagiota; Kitsantas, Thomas

2012-01-01

The purpose of this exploratory study was to assess the relative importance of a number of variables in predicting students' interest in math and/or computer science. Classification and regression trees (CART) were employed in the analysis of survey data collected from 276 college students enrolled in two U.S. and Greek universities. The results…

Using a stochastic model and cross-scale analysis to evaluate controls on historical low-severity fire regimes

Treesearch

Maureen C. Kennedy; Donald McKenzie

2010-01-01

Fire-scarred trees provide a deep temporal record of historical fire activity, but identifying the mechanisms therein that controlled landscape fire patterns is not straightforward. We use a spatially correlated metric for fire co-occurrence between pairs of trees (the Sørensen distance variogram), with output from a neutral model for fire history, to infer the...

A Search for the tt¯H (H → bb) Large Hadron Collider with the atlas detector using a matrix element method

NASA Astrophysics Data System (ADS)

Basye, Austin T.

A matrix element method analysis of the Standard Model Higgs boson, produced in association with two top quarks decaying to the lepton-plus-jets channel is presented. Based on 20.3 fb--1 of s=8 TeV data, produced at the Large Hadron Collider and collected by the ATLAS detector, this analysis utilizes multiple advanced techniques to search for ttH signatures with a 125 GeV Higgs boson decaying to two b -quarks. After categorizing selected events based on their jet and b-tag multiplicities, signal rich regions are analyzed using the matrix element method. Resulting variables are then propagated to two parallel multivariate analyses utilizing Neural Networks and Boosted Decision Trees respectively. As no significant excess is found, an observed (expected) limit of 3.4 (2.2) times the Standard Model cross-section is determined at 95% confidence, using the CLs method, for the Neural Network analysis. For the Boosted Decision Tree analysis, an observed (expected) limit of 5.2 (2.7) times the Standard Model cross-section is determined at 95% confidence, using the CLs method. Corresponding unconstrained fits of the Higgs boson signal strength to the observed data result in the measured signal cross-section to Standard Model cross-section prediction of mu = 1.2 +/- 1.3(total) +/- 0.7(stat.) for the Neural Network analysis, and mu = 2.9 +/- 1.4(total) +/- 0.8(stat.) for the Boosted Decision Tree analysis.

Image compression using quad-tree coding with morphological dilation

NASA Astrophysics Data System (ADS)

Wu, Jiaji; Jiang, Weiwei; Jiao, Licheng; Wang, Lei

2007-11-01

In this paper, we propose a new algorithm which integrates morphological dilation operation to quad-tree coding, the purpose of doing this is to compensate each other's drawback by using quad-tree coding and morphological dilation operation respectively. New algorithm can not only quickly find the seed significant coefficient of dilation but also break the limit of block boundary of quad-tree coding. We also make a full use of both within-subband and cross-subband correlation to avoid the expensive cost of representing insignificant coefficients. Experimental results show that our algorithm outperforms SPECK and SPIHT. Without using any arithmetic coding, our algorithm can achieve good performance with low computational cost and it's more suitable to mobile devices or scenarios with a strict real-time requirement.

Development of an outdoor MRI system for measuring flow in a living tree

NASA Astrophysics Data System (ADS)

Nagata, Akiyoshi; Kose, Katsumi; Terada, Yasuhiko

2016-04-01

An outdoor MRI system for noninvasive, long-term measurements of sap flow in a living tree in its natural environment has been developed. An open-access, 0.2 T permanent magnet with a 160 mm gap was combined with a radiofrequency probe, planar gradient coils, electromagnetic shielding, several electrical units, and a waterproofing box. Two-dimensional cross-sectional images were acquired for a ring-porous tree, and the anatomical structures, including xylem and phloem, were identified. The MRI flow measurements demonstrated the diurnal changes in flow velocity in the stem on a per-pixel basis. These results demonstrate that our outdoor MRI system is a powerful tool for studies of water transport in outdoor trees.

Urban Tree Risk Management:A Community Guide to Program Design and Implementation

Treesearch

Jill Pokorny; Joseph O' Brien; Richard Hauer; Gary Johnson; Jana Albers; Peter Bedker; Manfred Mielke

2003-01-01

Urban Tree Risk Management: A Community Guide to Program Design and Implementation is a fully illustrated, easy to read training manual written for community leaders, administrators, city foresters, parks and public works staff, and private tree care practitioners. The manual is designed to assist communities design, adopt and implement tree risk management programs,...

Proceedings: third lake states forest tree improvement conference

Treesearch

Forest Service U.S.

1958-01-01

The Third Lake States Forest Tree Improvement Conference culminated the activities of the Lake States Forest Tree Improvement Committee and offered an opportmity to report on committee work for the past biennium. It also provided an important means for the Committee to meet its major objective - the encouraging and coordinating of forest tree improvement activities in...

Tree mortality from drought, insects, and their interactions in a changing climate

USGS Publications Warehouse

Anderegg, William R.L.; Hicke, Jeffrey A.; Fisher, Rosie A.; Allen, Craig D.; Aukema, Juliann E.; Bentz, Barbara; Hood, Sharon; Lichstein, Jeremy W.; Macalady, Alison K.; McDowell, Nate G.; Pan, Yude; Raffa, Kenneth; Sala, Anna; Shaw, John D.; Stephenson, Nathan L.; Tague, Christina L.; Zeppel, Melanie

2015-01-01

Climate change is expected to drive increased tree mortality through drought, heat stress, and insect attacks, with manifold impacts on forest ecosystems. Yet, climate-induced tree mortality and biotic disturbance agents are largely absent from process-based ecosystem models. Using data sets from the western USA and associated studies, we present a framework for determining the relative contribution of drought stress, insect attack, and their interactions, which is critical for modeling mortality in future climates. We outline a simple approach that identifies the mechanisms associated with two guilds of insects – bark beetles and defoliators – which are responsible for substantial tree mortality. We then discuss cross-biome patterns of insect-driven tree mortality and draw upon available evidence contrasting the prevalence of insect outbreaks in temperate and tropical regions. We conclude with an overview of tools and promising avenues to address major challenges. Ultimately, a multitrophic approach that captures tree physiology, insect populations, and tree–insect interactions will better inform projections of forest ecosystem responses to climate change.

Tree mortality from drought, insects, and their interactions in a changing climate.

PubMed

Anderegg, William R L; Hicke, Jeffrey A; Fisher, Rosie A; Allen, Craig D; Aukema, Juliann; Bentz, Barbara; Hood, Sharon; Lichstein, Jeremy W; Macalady, Alison K; McDowell, Nate; Pan, Yude; Raffa, Kenneth; Sala, Anna; Shaw, John D; Stephenson, Nathan L; Tague, Christina; Zeppel, Melanie

2015-11-01

Climate change is expected to drive increased tree mortality through drought, heat stress, and insect attacks, with manifold impacts on forest ecosystems. Yet, climate-induced tree mortality and biotic disturbance agents are largely absent from process-based ecosystem models. Using data sets from the western USA and associated studies, we present a framework for determining the relative contribution of drought stress, insect attack, and their interactions, which is critical for modeling mortality in future climates. We outline a simple approach that identifies the mechanisms associated with two guilds of insects - bark beetles and defoliators - which are responsible for substantial tree mortality. We then discuss cross-biome patterns of insect-driven tree mortality and draw upon available evidence contrasting the prevalence of insect outbreaks in temperate and tropical regions. We conclude with an overview of tools and promising avenues to address major challenges. Ultimately, a multitrophic approach that captures tree physiology, insect populations, and tree-insect interactions will better inform projections of forest ecosystem responses to climate change. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Metric Sex Determination of the Human Coxal Bone on a Virtual Sample using Decision Trees.

PubMed

Savall, Frédéric; Faruch-Bilfeld, Marie; Dedouit, Fabrice; Sans, Nicolas; Rousseau, Hervé; Rougé, Daniel; Telmon, Norbert

2015-11-01

Decision trees provide an alternative to multivariate discriminant analysis, which is still the most commonly used in anthropometric studies. Our study analyzed the metric characterization of a recent virtual sample of 113 coxal bones using decision trees for sex determination. From 17 osteometric type I landmarks, a dataset was built with five classic distances traditionally reported in the literature and six new distances selected using the two-step ratio method. A ten-fold cross-validation was performed, and a decision tree was established on two subsamples (training and test sets). The decision tree established on the training set included three nodes and its application to the test set correctly classified 92% of individuals. This percentage was similar to the data of the literature. The usefulness of decision trees has been demonstrated in numerous fields. They have been already used in sex determination, body mass prediction, and ancestry estimation. This study shows another use of decision trees enabling simple and accurate sex determination. © 2015 American Academy of Forensic Sciences.

Improving medical diagnosis reliability using Boosted C5.0 decision tree empowered by Particle Swarm Optimization.

PubMed

Pashaei, Elnaz; Ozen, Mustafa; Aydin, Nizamettin

2015-08-01

Improving accuracy of supervised classification algorithms in biomedical applications is one of active area of research. In this study, we improve the performance of Particle Swarm Optimization (PSO) combined with C4.5 decision tree (PSO+C4.5) classifier by applying Boosted C5.0 decision tree as the fitness function. To evaluate the effectiveness of our proposed method, it is implemented on 1 microarray dataset and 5 different medical data sets obtained from UCI machine learning databases. Moreover, the results of PSO + Boosted C5.0 implementation are compared to eight well-known benchmark classification methods (PSO+C4.5, support vector machine under the kernel of Radial Basis Function, Classification And Regression Tree (CART), C4.5 decision tree, C5.0 decision tree, Boosted C5.0 decision tree, Naive Bayes and Weighted K-Nearest neighbor). Repeated five-fold cross-validation method was used to justify the performance of classifiers. Experimental results show that our proposed method not only improve the performance of PSO+C4.5 but also obtains higher classification accuracy compared to the other classification methods.

Tree decline and the future of Australian farmland biodiversity

PubMed Central

Fischer, Joern; Zerger, Andre; Gibbons, Phil; Stott, Jenny; Law, Bradley S.

2010-01-01

Farmland biodiversity is greatly enhanced by the presence of trees. However, farmland trees are declining worldwide, including in North America, Central America, and parts of southern Europe. We show that tree decline and its likely consequences are particularly severe in Australia's temperate agricultural zone, which is a threatened ecoregion. Using field data on trees, remotely sensed imagery, and a demographic model for trees, we predict that by 2100, the number of trees on an average farm will contract to two-thirds of its present level. Statistical habitat models suggest that this tree decline will negatively affect many currently common animal species, with predicted declines in birds and bats of up to 50% by 2100. Declines were predicted for 24 of 32 bird species modeled and for all of six bat species modeled. Widespread declines in trees, birds, and bats may lead to a reduction in economically important ecosystem services such as shade provision for livestock and pest control. Moreover, many other species for which we have no empirical data also depend on trees, suggesting that fundamental changes in ecosystem functioning are likely. We conclude that Australia's temperate agricultural zone has crossed a threshold and no longer functions as a self-sustaining woodland ecosystem. A regime shift is occurring, with a woodland system deteriorating into a treeless pasture system. Management options exist to reverse tree decline, but new policy settings are required to encourage their widespread adoption. PMID:20974946

Encoding phylogenetic trees in terms of weighted quartets.

PubMed

Grünewald, Stefan; Huber, Katharina T; Moulton, Vincent; Semple, Charles

2008-04-01

One of the main problems in phylogenetics is to develop systematic methods for constructing evolutionary or phylogenetic trees. For a set of species X, an edge-weighted phylogenetic X-tree or phylogenetic tree is a (graph theoretical) tree with leaf set X and no degree 2 vertices, together with a map assigning a non-negative length to each edge of the tree. Within phylogenetics, several methods have been proposed for constructing such trees that work by trying to piece together quartet trees on X, i.e. phylogenetic trees each having four leaves in X. Hence, it is of interest to characterise when a collection of quartet trees corresponds to a (unique) phylogenetic tree. Recently, Dress and Erdös provided such a characterisation for binary phylogenetic trees, that is, phylogenetic trees all of whose internal vertices have degree 3. Here we provide a new characterisation for arbitrary phylogenetic trees.

Modeling time-to-event (survival) data using classification tree analysis.

PubMed

Linden, Ariel; Yarnold, Paul R

2017-12-01

Time to the occurrence of an event is often studied in health research. Survival analysis differs from other designs in that follow-up times for individuals who do not experience the event by the end of the study (called censored) are accounted for in the analysis. Cox regression is the standard method for analysing censored data, but the assumptions required of these models are easily violated. In this paper, we introduce classification tree analysis (CTA) as a flexible alternative for modelling censored data. Classification tree analysis is a "decision-tree"-like classification model that provides parsimonious, transparent (ie, easy to visually display and interpret) decision rules that maximize predictive accuracy, derives exact P values via permutation tests, and evaluates model cross-generalizability. Using empirical data, we identify all statistically valid, reproducible, longitudinally consistent, and cross-generalizable CTA survival models and then compare their predictive accuracy to estimates derived via Cox regression and an unadjusted naïve model. Model performance is assessed using integrated Brier scores and a comparison between estimated survival curves. The Cox regression model best predicts average incidence of the outcome over time, whereas CTA survival models best predict either relatively high, or low, incidence of the outcome over time. Classification tree analysis survival models offer many advantages over Cox regression, such as explicit maximization of predictive accuracy, parsimony, statistical robustness, and transparency. Therefore, researchers interested in accurate prognoses and clear decision rules should consider developing models using the CTA-survival framework. © 2017 John Wiley & Sons, Ltd.

Heat exposure and productivity in orchards: Implications for climate change research.

PubMed

Quiller, Grant; Krenz, Jennifer; Ebi, Kristie; Hess, Jeremy J; Fenske, Richard A; Sampson, Paul D; Pan, Mengjie; Spector, June T

2017-11-02

Recent studies suggest that heat exposure degrades work productivity, but such studies have not considered individual- and workplace-level factors. Forty-six tree-fruit harvesters (98% Latino/a) from 6 orchards participated in a cross-sectional study in central/eastern Washington in 2015. The association between maximum measured work-shift wet-bulb globe temperature (WBGT max ) and productivity (total weight of fruit bins collected per time worked) was estimated using linear mixed-effects models, adjusting for relevant confounders. The mean (standard deviation) WBGT max was 27.9°C (3.6°C) in August and 21.2°C (2.0°C) in September. There was a trend of decreasing productivity with increasing WBGT max , but this association was not statistically significant. When individual- and workplace-level factors were included in the model, the association approached the null. Not considering individual, work, and economic factors that affect rest and recovery in projections of the effects of climate change could result in overestimates of reductions in future productivity and underestimate risk of heat illness.

Computationally predicted IgE epitopes of walnut allergens contribute to cross-reactivity with peanuts

USDA-ARS?s Scientific Manuscript database

Cross reactivity between peanuts and tree nuts implies that similar IgE epitopes are present in their proteins. To determine whether walnut sequences similar to known peanut IgE binding sequences, according to the property distance (PD) scale implemented in the Structural Database of Allergenic Prot...

Thermal Energy Storage in Phase Change Material.

DTIC Science & Technology

1982-03-01

Graphs of the exnerimental results follow: tney are groupea in the tree categories: tube cross flow, ricked bed, and tube parallel flow. A. Tube Cross... Riordan , Michael, "Thermal Storage: A Rtsic Guile to the Ptate of the Art", Solar Age, Aril, 1978, P. 10. 5. Telkes, Maria, "Thermal Lner y Storage in

Mechanical properties of individual southern pine fibers. Part III. Global relationships between fiber properties and fiber location within an individual tree.

Treesearch

Leslie H. Groom; Stephen Shaler; Laurence Mott

2002-01-01

This is the third and final paper in a three-part series investigating the effect of location within a tree on the mechanical properties of individual wood tracheids. This paper focuses on the definition of juvenile, transition, and mature zones as classified by fiber stiffness, strength, microfibril angle, and cross-sectional area. The average modulus of elasticity...

Mechanical Properties of Individual Southern Pine Fibers. Part III: Global Relationships Between Fiber Properties and Fiber Location Within An Individual Tree

Treesearch

Les Groom; Stephen Shaler; Laurence Mott

2002-01-01

This is the third and final paper in a three-part series investigating the effect of location within a tree on the mechanical properties of individual wood tracheids. This paper focuses on the definition of juvenile, transition, and mature zones as classified by fiber stiffness, strength, microfibril angle, and cross-sectional area. The average modulus of elasticity...

Vertical Stability of Ephemeral Step-Pool Streams Largely Controlled By Tree Roots, Central Kentucky, USA

NASA Astrophysics Data System (ADS)

Macmannis, K. R.; Hawley, R. J.

2013-12-01

The mechanisms controlling stability on small streams in steep settings are not well documented but have many implications related to stream integrity and water quality. For example, channel instability on first and second order streams is a potential source of sediment in regulated areas with Total Maximum Daily Loads (TMDLs) on water bodies that are impaired for sedimentation, such as the Chesapeake Bay. Management strategies that preserve stream integrity and protect channel stability are critical to communities that may otherwise require large capital investments to meet TMDLs and other water quality criteria. To contribute to an improved understanding of ephemeral step-pool systems, we collected detailed hydrogeomorphic data on 4 steep (0.06 - 0.12 meter/meter) headwater streams draining to lower relief alluvial valleys in Spencer County, Kentucky, USA. The step-pool streams (mean step height of 0.47 meter, mean step spacing of 4 meters) drained small undeveloped catchments dominated by early successional forest. Data collection for each of the 4 streams included 2 to 3 cross section surveys, bed material particle counts at cross section locations, and profile surveys ranging from approximately 125 to 225 meters in length. All survey data was systematically processed to understand geometric parameters such as cross sectional area, depth, and top width; bed material gradations; and detailed profile measurements such as slope, pool and riffle lengths, pool spacing, pool depth, step height, and step length. We documented the location, frequency, and type of step-forming materials (i.e., large woody debris (LWD), rock, and tree roots), compiling a database of approximately 130 total steps. Lastly, we recorded a detailed tree assessment of all trees located within 2 meters of the top of bank, detailing the species of tree, trunk diameter, and approximate distance from the top of bank. Analysis of geometric parameters illustrated correlations between channel characteristics (e.g., step height was positively correlated to slope while pool spacing was inversely correlated to slope). Most importantly, we assessed the step-forming materials with respect to channel stability. LWD has been widely documented as an important component of geomorphic stability and habitat diversity across many settings; however, our research highlights the importance of roots in providing bed stability in steep, first and second-order ephemeral streams, as 40 percent of the steps in these step-pool systems were controlled by tree roots. Similar to the key member in naturally-occurring log jams, lateral tree roots frequently served as the anchor for channel steps that were often supplemented by rocks or LWD. Assessment of the trees throughout the riparian zone suggested average tree densities of 0.30 trees/square meter or 0.40 trees/meter could provide adequate riparian zone coverage to promote channel stability. These results have implications to land use planning and stormwater management. For example, on developments draining to step-pool systems, maintaining the integrity of the riparian zone would seem to be as important as ensuring hydrologic mimicry if channel integrity is to be preserved.

Failure mechanism of hollow tree trunks due to cross-sectional flattening

PubMed Central

Huang, Yan-San; Hsu, Fu-Lan; Lee, Chin-Mei

2017-01-01

Failure of hollow trees in urban areas is a worldwide concern, and it can be caused by different mechanisms, i.e. bending stresses or flattening-related failures. Here we derive a new analytical expression for predicting the bending moment for tangential cracking, and compare the breaking moment of various failure modes, including Brazier buckling, tangential cracking, shear failure and conventional bending failure, as a function of t/R ratio, where t and R are the trunk wall thickness and trunk radius, respectively, of a hollow tree. We use Taiwan red cypress as an example and show that its failure modes and the corresponding t/R ratios are: Brazier buckling (Mode I), tangential cracking followed by longitudinal splitting (Mode II) and conventional bending failure (Mode III) for 0 < t/R < 0.06, 0.06 < t/R < 0.27 and 0.27 < t/R < 1, respectively. The exact values of those ratios may vary within and among species, but the variation is much smaller than individual mechanical properties. Also, shear failure, another type of cracking due to maximum shear stress near the neutral axis of the tree trunk, is unlikely to occur since it requires much larger bending moments. Hence, we conclude that tangential cracking due to cross-sectional flattening, followed by longitudinal splitting, is dominant for hollow trunks. Our equations are applicable to analyse straight hollow tree trunks and plant stems, but are not applicable to those with side openings or those with only heart decay. Our findings provide insights for those managing trees in urban situations and those managing for conservation of hollow-dependent fauna in both urban and rural settings. PMID:28484616

Recruiting Conventional Tree Architecture Models into State-of-the-Art LiDAR Mapping for Investigating Tree Growth Habits in Structure.

PubMed

Lin, Yi; Jiang, Miao; Pellikka, Petri; Heiskanen, Janne

2018-01-01

Mensuration of tree growth habits is of considerable importance for understanding forest ecosystem processes and forest biophysical responses to climate changes. However, the complexity of tree crown morphology that is typically formed after many years of growth tends to render it a non-trivial task, even for the state-of-the-art 3D forest mapping technology-light detection and ranging (LiDAR). Fortunately, botanists have deduced the large structural diversity of tree forms into only a limited number of tree architecture models, which can present a-priori knowledge about tree structure, growth, and other attributes for different species. This study attempted to recruit Hallé architecture models (HAMs) into LiDAR mapping to investigate tree growth habits in structure. First, following the HAM-characterized tree structure organization rules, we run the kernel procedure of tree species classification based on the LiDAR-collected point clouds using a support vector machine classifier in the leave-one-out-for-cross-validation mode. Then, the HAM corresponding to each of the classified tree species was identified based on expert knowledge, assisted by the comparison of the LiDAR-derived feature parameters. Next, the tree growth habits in structure for each of the tree species were derived from the determined HAM. In the case of four tree species growing in the boreal environment, the tests indicated that the classification accuracy reached 85.0%, and their growth habits could be derived by qualitative and quantitative means. Overall, the strategy of recruiting conventional HAMs into LiDAR mapping for investigating tree growth habits in structure was validated, thereby paving a new way for efficiently reflecting tree growth habits and projecting forest structure dynamics.

Recruiting Conventional Tree Architecture Models into State-of-the-Art LiDAR Mapping for Investigating Tree Growth Habits in Structure

PubMed Central

Lin, Yi; Jiang, Miao; Pellikka, Petri; Heiskanen, Janne

2018-01-01

Mensuration of tree growth habits is of considerable importance for understanding forest ecosystem processes and forest biophysical responses to climate changes. However, the complexity of tree crown morphology that is typically formed after many years of growth tends to render it a non-trivial task, even for the state-of-the-art 3D forest mapping technology—light detection and ranging (LiDAR). Fortunately, botanists have deduced the large structural diversity of tree forms into only a limited number of tree architecture models, which can present a-priori knowledge about tree structure, growth, and other attributes for different species. This study attempted to recruit Hallé architecture models (HAMs) into LiDAR mapping to investigate tree growth habits in structure. First, following the HAM-characterized tree structure organization rules, we run the kernel procedure of tree species classification based on the LiDAR-collected point clouds using a support vector machine classifier in the leave-one-out-for-cross-validation mode. Then, the HAM corresponding to each of the classified tree species was identified based on expert knowledge, assisted by the comparison of the LiDAR-derived feature parameters. Next, the tree growth habits in structure for each of the tree species were derived from the determined HAM. In the case of four tree species growing in the boreal environment, the tests indicated that the classification accuracy reached 85.0%, and their growth habits could be derived by qualitative and quantitative means. Overall, the strategy of recruiting conventional HAMs into LiDAR mapping for investigating tree growth habits in structure was validated, thereby paving a new way for efficiently reflecting tree growth habits and projecting forest structure dynamics. PMID:29515616

Why count trees? Volunteer motivations and experiences with tree monitoring in New York City

Treesearch

Michelle L. Johnson; Lindsay K. Campbell; Erika S. Svendsen; Philip Silva

2018-01-01

Volunteer programs can benefit from a deeper understanding of the motivations and experiences of people engaged in citizen science. Research to date has studied motivations of citizen scientists and tree-planting volunteers. Less work has focused on tree-monitoring volunteers, a role that is rapidly increasing as more cities involve the public in monitoring the urban...

Legacy tree data: A national database of detailed tree measurements for volume, weight, and physical properties

Treesearch

P.J. Radtke; D.M. Walker; A.R. Weiskittel; J. Frank; J.W. Coulston; J.A. Westfall

2015-01-01

Forest mensurationists in the United States have expended considerable effort over the past century making detailed observations of trees’ dimensions. In recent decades efforts have focused increasingly on weights and physical properties. Work is underway to compile original measurements from past volume, taper, and weight or biomass studies for North American tree...

Applying and Individual-Based Model to Simultaneously Evaluate Net Ecosystem Production and Tree Diameter Increment

NASA Astrophysics Data System (ADS)

Fang, F. J.

2017-12-01

Reconciling observations at fundamentally different scales is central in understanding the global carbon cycle. This study investigates a model-based melding of forest inventory data, remote-sensing data and micrometeorological-station data ("flux towers" estimating forest heat, CO2 and H2O fluxes). The individual tree-based model FORCCHN was used to evaluate the tree DBH increment and forest carbon fluxes. These are the first simultaneous simulations of the forest carbon budgets from flux towers and individual-tree growth estimates of forest carbon budgets using the continuous forest inventory data — under circumstances in which both predictions can be tested. Along with the global implications of such findings, this also improves the capacity for forest sustainable management and the comprehensive understanding of forest ecosystems. In forest ecology, diameter at breast height (DBH) of a tree significantly determines an individual tree's cross-sectional sapwood area, its biomass and carbon storage. Evaluation the annual DBH increment (ΔDBH) of an individual tree is central to understanding tree growth and forest ecology. Ecosystem Carbon flux is a consequence of key ecosystem processes in the forest-ecosystem carbon cycle, Gross and Net Primary Production (GPP and NPP, respectively) and Net Ecosystem Respiration (NEP). All of these closely relate with tree DBH changes and tree death. Despite advances in evaluating forest carbon fluxes with flux towers and forest inventories for individual tree ΔDBH, few current ecological models can simultaneously quantify and predict the tree ΔDBH and forest carbon flux.

On the distribution of interspecies correlation for Markov models of character evolution on Yule trees.

PubMed

Mulder, Willem H; Crawford, Forrest W

2015-01-07

Efforts to reconstruct phylogenetic trees and understand evolutionary processes depend fundamentally on stochastic models of speciation and mutation. The simplest continuous-time model for speciation in phylogenetic trees is the Yule process, in which new species are "born" from existing lineages at a constant rate. Recent work has illuminated some of the structural properties of Yule trees, but it remains mostly unknown how these properties affect sequence and trait patterns observed at the tips of the phylogenetic tree. Understanding the interplay between speciation and mutation under simple models of evolution is essential for deriving valid phylogenetic inference methods and gives insight into the optimal design of phylogenetic studies. In this work, we derive the probability distribution of interspecies covariance under Brownian motion and Ornstein-Uhlenbeck models of phenotypic change on a Yule tree. We compute the probability distribution of the number of mutations shared between two randomly chosen taxa in a Yule tree under discrete Markov mutation models. Our results suggest summary measures of phylogenetic information content, illuminate the correlation between site patterns in sequences or traits of related organisms, and provide heuristics for experimental design and reconstruction of phylogenetic trees. Copyright © 2014 Elsevier Ltd. All rights reserved.

Prediction of Baseflow Index of Catchments using Machine Learning Algorithms

NASA Astrophysics Data System (ADS)

Yadav, B.; Hatfield, K.

2017-12-01

We present the results of eight machine learning techniques for predicting the baseflow index (BFI) of ungauged basins using a surrogate of catchment scale climate and physiographic data. The tested algorithms include ordinary least squares, ridge regression, least absolute shrinkage and selection operator (lasso), elasticnet, support vector machine, gradient boosted regression trees, random forests, and extremely randomized trees. Our work seeks to identify the dominant controls of BFI that can be readily obtained from ancillary geospatial databases and remote sensing measurements, such that the developed techniques can be extended to ungauged catchments. More than 800 gauged catchments spanning the continental United States were selected to develop the general methodology. The BFI calculation was based on the baseflow separated from daily streamflow hydrograph using HYSEP filter. The surrogate catchment attributes were compiled from multiple sources including digital elevation model, soil, landuse, climate data, other publicly available ancillary and geospatial data. 80% catchments were used to train the ML algorithms, and the remaining 20% of the catchments were used as an independent test set to measure the generalization performance of fitted models. A k-fold cross-validation using exhaustive grid search was used to fit the hyperparameters of each model. Initial model development was based on 19 independent variables, but after variable selection and feature ranking, we generated revised sparse models of BFI prediction that are based on only six catchment attributes. These key predictive variables selected after the careful evaluation of bias-variance tradeoff include average catchment elevation, slope, fraction of sand, permeability, temperature, and precipitation. The most promising algorithms exceeding an accuracy score (r-square) of 0.7 on test data include support vector machine, gradient boosted regression trees, random forests, and extremely randomized trees. Considering both the accuracy and the computational complexity of these algorithms, we identify the extremely randomized trees as the best performing algorithm for BFI prediction in ungauged basins.

Comparative Use of Tree Leaves, Needles, Tree Barks and Lichens for Air Pollution Biomonitoring

NASA Astrophysics Data System (ADS)

El Khoukhi, T.; Cherkaoui El Moursli, R.; Chouak, A.; Moutia, Z.; Lferde, M.; Senhou, A.; Gaudry, A.; Ayrault, S.; Chakir, M.

2005-01-01

The aim of this work is to determine the most suitable bioaccumulators for air pollution survey in Morocco. For this, we compare in this paper heavy metals uptake efficiencies for different types of biomonitors: leaves of oak and eucalyptus trees, needles of coniferous trees, tree-barks and lichens collected at the same site. Instrumental neutron activation analysis using the k0 method (INAA-k0) was used for its adequate characteristics to analyze accurately a wide number of elements. Reference materials were analyzed to check the reliability and the accuracy of this technique. The results obtained for all these bioaccumulators lead to the following conclusions. For the major elements, leaves and needles are more accumulating than tree barks and lichens. While for the intermediate and trace elements, there is an obvious accumulation in lichens in comparison with tree barks, leaves and needles. This work shows the possibility to use these four bioaccumulators according to their availability in an area. It will be useful however to set up an inter calibration between these bioaccumulators.

Assessing visual green effects of individual urban trees using airborne Lidar data.

PubMed

Chen, Ziyue; Xu, Bing; Gao, Bingbo

2015-12-01

Urban trees benefit people's daily life in terms of air quality, local climate, recreation and aesthetics. Among these functions, a growing number of studies have been conducted to understand the relationship between residents' preference towards local environments and visual green effects of urban greenery. However, except for on-site photography, there are few quantitative methods to calculate green visibility, especially tree green visibility, from viewers' perspectives. To fill this research gap, a case study was conducted in the city of Cambridge, which has a diversity of tree species, sizes and shapes. Firstly, a photograph-based survey was conducted to approximate the actual value of visual green effects of individual urban trees. In addition, small footprint airborne Lidar (Light detection and ranging) data was employed to measure the size and shape of individual trees. Next, correlations between visual tree green effects and tree structural parameters were examined. Through experiments and gradual refinement, a regression model with satisfactory R2 and limited large errors is proposed. Considering the diversity of sample trees and the result of cross-validation, this model has the potential to be applied to other study sites. This research provides urban planners and decision makers with an innovative method to analyse and evaluate landscape patterns in terms of tree greenness. Copyright © 2015 Elsevier B.V. All rights reserved.

Ergonomics aspects of tree-planting using 'multipot' technology.

PubMed

Giguère, D; Bélanger, R; Gauthier, J M; Larue, C

1993-08-01

The highlights of a descriptive study on the ergonomics and occupational health and safety aspects of tree-planting in Québec are presented. The study was planned to consider the most representative geographical sites, planting technologies, and planting organizations. Semi-directed interviews were made with a mixed group of 48 male and female tree-planters and physiological measurements were made on four male planters. Tools and other equipment were also examined. An analysis of the work identified the main elements of the planting cycle, and the high cardiac rate in the working planters was related more to his manual transportation of seedlings and travel on rough paths than to planting per se. A tree-planter will typically travel 2.4 km carrying 16.8 kg of material and equipment in order to plant an average of 1245 seedlings daily. One out of two interviewed planters reported having a work-related accident or incident during his or her lifetime planting career. The body parts reported most frequently injured were the lower extremities (knee, foot, ankle), the skin, the eyes, and the wrist. Recommendations on the development of appropriate tools and footwear for tree-planters and for further research on repetitive strain injury induced by tree-planting have been made.

Variation of Specific Gravity in Plantation-Grown Trees of Bigleaf Mahogany

Treesearch

C. B. Briscoe; J. B. Harris; D. Wyckoff

1963-01-01

As a prelude to tree improvement work in the genus Swietenia, a study was made of specific gravity variation within the bole of six plantation-grown trees of bigleaf mahogany. Variation was appreciable, from 0.36 to 0.65 , and several patterns were determined. Specific gravity of the tree increased with growth rate, as expressed in diameter at breast height, but not...

Applications and Benefits for Big Data Sets Using Tree Distances and The T-SNE Algorithm

DTIC Science & Technology

2016-03-01

BENEFITS FOR BIG DATA SETS USING TREE DISTANCES AND THE T-SNE ALGORITHM by Suyoung Lee March 2016 Thesis Advisor: Samuel E. Buttrey...REPORT TYPE AND DATES COVERED Master’s thesis 4. TITLE AND SUBTITLE APPLICATIONS AND BENEFITS FOR BIG DATA SETS USING TREE DISTANCES AND THE T-SNE...this work we use tree distance computed using Buttrey’s treeClust package in R, as discussed by Buttrey and Whitaker in 2015, to process mixed data

Seasonality and Disturbance Events in the Carbon Isotope Record of Pinus elliottii Tree Rings from Big Pine Key, Florida

NASA Astrophysics Data System (ADS)

Rebenack, C.; Anderson, W. T.; Cherubini, P.

2012-12-01

The South Florida coastal ecosystem is among the world's subtropical coastlines which are threatened by the potential effects of climate change. A well-developed localized paleohistory is essential in the understanding of the role climate variability/change has on both hydrological dynamics and disturbance event frequency and intensity; this understanding can then aid in the development of better predictive models. High resolution paleoclimate proxies, such as those developed from tree-ring archives, may be useful tools for extrapolating actual climate trends over time from the overlapping long-term and short-term climate cycles, such as the Atlantic Multidecadal Oscillation (AMO) and the El Niño-Southern Oscillation (ENSO). In South Florida, both the AMO and ENSO strongly influence seasonal precipitation, and a more complete grasp of how these cycles have affected the region in the past could be applied to future freshwater management practices. Dendrochronology records for the terrestrial subtropics, including South Florida, are sparse because seasonality for this region is precipitation-driven; this is in contrast to the drastic temperature changes experienced in the temperate latitudes. Subtropical seasonality may lead to the complete lack of visible rings or to the formation of ring structures that may or may not represent annual growth. Fortunately, it has recently been demonstrated that Pinus elliottii trees in South Florida produce distinct annual growth rings; however ring width was not found to significantly correlate with either the AMO or ENSO. Dendrochronology studies may be taken a step beyond the physical tree-ring proxies by using the carbon isotope ratios to infer information about physiological controls and environmental factors that affect the distribution of isotopes within the plant. It has been well established that the stable isotope composition of cellulose can be related to precipitation, drought, large-scale ocean/atmospheric oscillations, and disturbance events, such as tropical cyclone impacts. Because slash pine growth is dependent on water availability, a chronology developed using carbon isotopes may provide greater insight into plant stress over time and ultimately may lead to better correlations with climate oscillations. The work presented here is the result of a carbon-isotope study of four slash pine trees located across a freshwater gradient on Big Pine Key, Florida. A site chronology has been developed by cross-dating the δ13C records for each of the trees. The tree located on the distal edge of the freshwater gradient shows an overall enriched isotopic signature over time compared to the trees growing over a deeper part of the local freshwater lens, indicating that these trees are sensitive to water stress. In addition, the carbon isotope data show seasonal stomatal activity in the trees and indicate the timing of two disturbance events.

Tree-ring reconstructions of hydroclimatic variability in the Upper Colorado River Basin

NASA Astrophysics Data System (ADS)

Hidalgo-Leon, Hugo

Three major sources of improvements in tree-ring analysis and reconstruction of hydroclimatic variables are presented for the Upper Colorado River Basin (UCRB) in the southwestern U.S.: (1) Cross validation statistics are used for identifying optimal reconstruction models based on different alternatives of PCA-based regression. Results showed that a physically-consistent parsimonious model with low mean square error can be obtained by using strict rules for principal component selection and cross validation statistics. The improved methods were used to produce a ˜500 year high-resolution reconstruction of the UCRB's streamflow and compared with results of a previous reconstruction based on traditional procedures. (2) Tree-species' type was found to be a factor for determining chronology selection from dendrohydroclimatic models. The relative sensitivity of six tree species (Pinus edulis, Pseudotsuga menziesii, Pinus ponderosa, Pinus flexilis, Pinus aristata, and Picea engelmanni) to hydroclimatic extreme variations was determined using contingency table scores of tree-ring growth (at different lags) against hydroclimatic observations. Pinus edulis and Pseudotsuga menziesii were found to be the species most sensitive to low water. Results showed that tree-rings are biased towards greater sensitivity to hot-dry conditions and less responsive to cool-moist conditions. Resulted also showed higher streamflow response scores compared to precipitation implying a good integration and persistence representation of the basin through normal hydrological processes. (3) Previous reconstructions on the basin used data extending only up to 1963. This is an important limitation since hydroclimatic records from 1963 to the present show significantly different variation than prior to 1963. The changes are caused by variations in the strength of forcing mechanisms from the Pacific Ocean. A comparative analysis of the influence of North Pacific variation and El Nino/Southern Oscillation (ENSO) showed that the responses of Tropical and North Pacific forcing in UCRB's hydroclimate are different for annual precipitation and total streamflow and that these relationships have changed at decadal time scales. Furthermore, most of the few tree-rings available up to 1985, present the same shifts as the hydroclimatic variables studied. To capture the full range of variability observed in instrumental data is necessary to collect new tree-ring samples.

Estimating water use by sugar maple trees: considerations when using heat-pulse methods in trees with deep functional sapwood.

PubMed

Pausch, Roman C.; Grote, Edmund E.; Dawson, Todd E.

2000-03-01

Accurate estimates of sapwood properties (including radial depth of functional xylem and wood water content) are critical when using the heat pulse velocity (HPV) technique to estimate tree water use. Errors in estimating the volumetric water content (V(h)) of the sapwood, especially in tree species with a large proportion of sapwood, can cause significant errors in the calculations ofsap velocity and sap flow through tree boles. Scaling to the whole-stand level greatly inflates these errors. We determined the effects of season, tree size and radial wood depth on V(h) of wood cores removed from Acer saccharum Marsh. trees throughout 3 years in upstate New York. We also determined the effects of variation in V(h) on sap velocity and sap flow calculations based on HPV data collected from sap flow gauges inserted at four depths. In addition, we compared two modifications of Hatton's weighted average technique, the zero-step and zero-average methods, for determining sap velocity and sap flow at depths beyond those penetrated by the sap flow gauges. Parameter V(h) varied significantly with time of year (DOY), tree size (S), and radial wood depth (RD), and there were significant DOY x S and DOY x RD interactions. Use of a mean whole-tree V(h) value resulted in differences ranging from -6 to +47% for both sap velocity and sap flow for individual sapwood annuli compared with use of the V(h) value determined at the specific depth where a probe was placed. Whole-tree sap flow was 7% higher when calculated on the basis of the individual V(h) value compared with the mean whole-tree V(h) value. Calculated total sap flow for a tree with a DBH of 48.8 cm was 13 and 19% less using the zero-step and the zero-average velocity techniques, respectively, than the value obtained with Hatton's weighted average technique. Smaller differences among the three methods were observed for a tree with a DBH of 24.4 cm. We conclude that, for Acer saccharum: (1) mean V(h) changes significantly during the year and can range from nearly 50% during winter and early spring, to 20% during the growing season;(2) large trees have a significantly greater V(h) than small trees; (3) overall, V(h) decreases and then increases significantly with radial wood depth, suggesting that radial water movement and storage are highly dynamic; and (4) V(h) estimates can vary greatly and influence subsequent water use calculations depending on whether an average or an individual V(h) value for a wood core is used. For large diameter trees in which sapwood comprises a large fraction of total stem cross-sectional area (where sap flow gauges cannot be inserted across the entire cross-sectional area), the zero-average modification of Hatton's weighted average method reduces the potential for large errors in whole-tree and landscape water balance estimates based on the HPV method.

From Google Maps to a fine-grained catalog of street trees

NASA Astrophysics Data System (ADS)

Branson, Steve; Wegner, Jan Dirk; Hall, David; Lang, Nico; Schindler, Konrad; Perona, Pietro

2018-01-01

Up-to-date catalogs of the urban tree population are of importance for municipalities to monitor and improve quality of life in cities. Despite much research on automation of tree mapping, mainly relying on dedicated airborne LiDAR or hyperspectral campaigns, tree detection and species recognition is still mostly done manually in practice. We present a fully automated tree detection and species recognition pipeline that can process thousands of trees within a few hours using publicly available aerial and street view images of Google MapsTM. These data provide rich information from different viewpoints and at different scales from global tree shapes to bark textures. Our work-flow is built around a supervised classification that automatically learns the most discriminative features from thousands of trees and corresponding, publicly available tree inventory data. In addition, we introduce a change tracker that recognizes changes of individual trees at city-scale, which is essential to keep an urban tree inventory up-to-date. The system takes street-level images of the same tree location at two different times and classifies the type of change (e.g., tree has been removed). Drawing on recent advances in computer vision and machine learning, we apply convolutional neural networks (CNN) for all classification tasks. We propose the following pipeline: download all available panoramas and overhead images of an area of interest, detect trees per image and combine multi-view detections in a probabilistic framework, adding prior knowledge; recognize fine-grained species of detected trees. In a later, separate module, track trees over time, detect significant changes and classify the type of change. We believe this is the first work to exploit publicly available image data for city-scale street tree detection, species recognition and change tracking, exhaustively over several square kilometers, respectively many thousands of trees. Experiments in the city of Pasadena, California, USA show that we can detect >70% of the street trees, assign correct species to >80% for 40 different species, and correctly detect and classify changes in >90% of the cases.

Tree-ring δ13C and δ18O, leaf δ13C and wood and leaf N status demonstrate tree growth strategies and predict susceptibility to disturbance

PubMed Central

Billings, S.A.; Boone, A.S.; Stephen, F.M.

2016-01-01

Understanding how tree growth strategies may influence tree susceptibility to disturbance is an important goal, especially given projected increases in diverse ecological disturbances this century. We use growth responses of tree rings to climate, relationships between tree-ring stable isotopic signatures of carbon (δ13C) and oxygen (δ18O), wood nitrogen concentration [N], and contemporary leaf [N] and δ13C values to assess potential historic drivers of tree photosynthesis in dying and apparently healthy co-occurring northern red oak (Quercus rubra L. (Fagaceae)) during a region-wide oak decline event in Arkansas, USA. Bole growth of both healthy and dying trees responded negatively to drought severity (Palmer Drought Severity Index) and temperature; healthy trees exhibited a positive, but small, response to growing season precipitation. Contrary to expectations, tree-ring δ13C did not increase with drought severity. A significantly positive relationship between tree-ring δ13C and δ18O was evident in dying trees (P < 0.05) but not in healthy trees. Healthy trees’ wood exhibited lower [N] than that of dying trees throughout most of their lives (P < 0.05), and we observed a significant, positive relationship (P < 0.05) in healthy trees between contemporary leaf δ13C and leaf N (by mass), but not in dying trees. Our work provides evidence that for plants in which strong relationships between δ13C and δ18O are not evident, δ13C may be governed by plant N status. The data further imply that historic photosynthesis in healthy trees was linked to N status and, perhaps, C sink strength to a greater extent than in dying trees, in which tree-ring stable isotopes suggest that historic photosynthesis was governed primarily by stomatal regulation. This, in turn, suggests that assessing the relative dominance of photosynthetic capacity vs stomatal regulation as drivers of trees’ C accrual may be a feasible means of predicting tree responses to some disturbance events. Our work demonstrates that a dual isotope, tree-ring approach can be integrated with tree N status to begin to unravel a fundamental question in forest ecology: why do some trees die during a disturbance, while other conspecifics with apparently similar access to resources remain healthy? PMID:26960389

Tree mortality risk of oak due to gypsy moth

Treesearch

K.W. Gottschalk; J.J. Colbert; D.L. Feicht

1998-01-01

We present prediction models for estimating tree mortality resulting from gypsy moth, Lymantria dispar, defoliation in mixed oak, Quercus sp., forests. These models differ from previous work by including defoliation as a factor in the analysis. Defoliation intensity, initial tree crown condition (crown vigour), crown position, and...

Adaptive zero-tree structure for curved wavelet image coding

NASA Astrophysics Data System (ADS)

Zhang, Liang; Wang, Demin; Vincent, André

2006-02-01

We investigate the issue of efficient data organization and representation of the curved wavelet coefficients [curved wavelet transform (WT)]. We present an adaptive zero-tree structure that exploits the cross-subband similarity of the curved wavelet transform. In the embedded zero-tree wavelet (EZW) and the set partitioning in hierarchical trees (SPIHT), the parent-child relationship is defined in such a way that a parent has four children, restricted to a square of 2×2 pixels, the parent-child relationship in the adaptive zero-tree structure varies according to the curves along which the curved WT is performed. Five child patterns were determined based on different combinations of curve orientation. A new image coder was then developed based on this adaptive zero-tree structure and the set-partitioning technique. Experimental results using synthetic and natural images showed the effectiveness of the proposed adaptive zero-tree structure for encoding of the curved wavelet coefficients. The coding gain of the proposed coder can be up to 1.2 dB in terms of peak SNR (PSNR) compared to the SPIHT coder. Subjective evaluation shows that the proposed coder preserves lines and edges better than the SPIHT coder.

Wood traits related to size and life history of trees in a Panamanian rainforest.

PubMed

Hietz, Peter; Rosner, Sabine; Hietz-Seifert, Ursula; Wright, S Joseph

2017-01-01

Wood structure differs widely among tree species and species with faster growth, higher mortality and larger maximum size have been reported to have fewer but larger vessels and higher hydraulic conductivity (Kh). However, previous studies compiled data from various sources, often failed to control tree size and rarely controlled variation in other traits. We measured wood density, tree size and vessel traits for 325 species from a wet forest in Panama, and compared wood and leaf traits to demographic traits using species-level data and phylogenetically independent contrasts. Wood traits showed strong phylogenetic signal whereas pairwise relationships between traits were mostly phylogenetically independent. Trees with larger vessels had a lower fraction of the cross-sectional area occupied by vessel lumina, suggesting that the hydraulic efficiency of large vessels permits trees to dedicate a larger proportion of the wood to functions other than water transport. Vessel traits were more strongly correlated with the size of individual trees than with maximal size of a species. When individual tree size was included in models, Kh scaled positively with maximal size and was the best predictor for both diameter and biomass growth rates, but was unrelated to mortality. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Comparison of hyporheic flow and water quality in open and tree-covered banks downstream of Xin'an River dam, China

NASA Astrophysics Data System (ADS)

Liu, D.

2017-12-01

Plants, especially trees, in the riparian zone may have a significant impact on the flow rate, temperature and chemical properties of groundwater. A field study was conducted in the downstream bank of the Xin'an River dam, Zhejiang, China. In the field, two areas of about 20 meters apart were chosen, of which one was a open place and the other was covered with many orange trees. Comparison of hyporheic flow and water quality in the open and tree-covered banks were made by monitoring the water level, water temperature, water chemistry (March, 2015) along the cross sections perpendicular to the river. The analyses indicated that water level around the trees was relatively low in the day and high in the evening, thus changed the direction and magnitude of the natural groundwater flow velocity, totally strengthened the hyporheic exchange between the groundwater and river. The trees also changed the temperature distribution of the natural river bank, and induced the wider infiltration range of the low-temperature water. The temperature around the trees was relatively low in the day, yet it was high in the evening. Dissolved oxygen (DO) and electricity conductivity (EC) around the trees were significantly increased, yet the pH was almost unaffected.

Tasting the Tree of Life: Development of a Collaborative, Cross-Campus, Science Outreach Meal Event.

PubMed

Clement, Wendy L; Elliott, Kathryn T; Cordova-Hoyos, Okxana; Distefano, Isabel; Kearns, Kate; Kumar, Raagni; Leto, Ashley; Tumaliuan, Janis; Franchetti, Lauren; Kulesza, Evelyn; Tineo, Nicole; Mendes, Patrice; Roth, Karen; Osborn, Jeffrey M

2018-01-01

Communicating about science with the public can present a number of challenges, from participation to engagement to impact. In an effort to broadly communicate messages regarding biodiversity, evolution, and tree-thinking with the campus community at The College of New Jersey (TCNJ), a public, primarily undergraduate institution, we created a campus-wide, science-themed meal, "Tasting the Tree of Life: Exploring Biodiversity through Cuisine." We created nine meals that incorporated 149 species/ingredients across the Tree of Life. Each meal illustrated a scientific message communicated through interactions with undergraduate biology students, informational signs, and an interactive website. To promote tree-thinking, we reconstructed a phylogeny of all 149 ingredients. In total, 3,262 people attended the meal, and evaluations indicated that participants left with greater appreciation for the biodiversity and evolutionary relatedness of their food. A keynote lecture and a coordinated social media campaign enhanced the scientific messages, and media coverage extended the reach of this event. "Tasting the Tree of Life" highlights the potential of cuisine as a valuable science communication tool.

Reconstruction of late Holocene climate based on tree growth and mechanistic hierarchical models

USGS Publications Warehouse

Tipton, John; Hooten, Mevin B.; Pederson, Neil; Tingley, Martin; Bishop, Daniel

2016-01-01

Reconstruction of pre-instrumental, late Holocene climate is important for understanding how climate has changed in the past and how climate might change in the future. Statistical prediction of paleoclimate from tree ring widths is challenging because tree ring widths are a one-dimensional summary of annual growth that represents a multi-dimensional set of climatic and biotic influences. We develop a Bayesian hierarchical framework using a nonlinear, biologically motivated tree ring growth model to jointly reconstruct temperature and precipitation in the Hudson Valley, New York. Using a common growth function to describe the response of a tree to climate, we allow for species-specific parameterizations of the growth response. To enable predictive backcasts, we model the climate variables with a vector autoregressive process on an annual timescale coupled with a multivariate conditional autoregressive process that accounts for temporal correlation and cross-correlation between temperature and precipitation on a monthly scale. Our multi-scale temporal model allows for flexibility in the climate response through time at different temporal scales and predicts reasonable climate scenarios given tree ring width data.

Tree species diversity and its relationship to stand parameters and geomorphology features in the eastern Black Sea region forests of Turkey.

PubMed

Ozcelik, Ramazan; Gul, Altay Ugur; Merganic, Jan; Merganicova, Katarina

2008-05-01

We studied the effects of stand parameters (crown closure, basal area, stand volume, age, mean stand diameter number of trees, and heterogeneity index) and geomorphology features (elevation, aspect and slope) on tree species diversity in an example of untreated natural mixed forest stands in the eastern Black Sea region of Turkey. Tree species diversity and basal area heterogeneity in forest ecosystems are quantified using the Shannon-Weaver and Simpson indices. The relationship between tree species diversity basal area heterogeneity stand parameters and geomorphology features are examined using regression analysis. Our work revealed that the relationship between tree species diversity and stand parameters is loose with a correlation coefficient between 0.02 and 0.70. The correlation of basal area heterogeneity with stand parameters fluctuated between 0.004 and 0.77 (R2). According to our results, stands with higher tree species diversity are characterised by higher mean stand diameter number of diameter classes, basal area and lower homogeneity index value. Considering the effect of geomorphology features on tree species or basal area heterogeneity we found that all investigated relationships are loose with R < or = 0.24. A significant correlation was detected only between tree species diversity and aspect. Future work is required to verify the detected trends in behaviour of tree species diversity if it is to estimate from the usual forest stand parameters and topography characteristics.

Geographic and phenotypic variation in heartwood and essential-oil characters in natural populations of Santalum austrocaledonicum in Vanuatu.

PubMed

Page, Tony; Southwell, Ian; Russell, Mike; Tate, Hanington; Tungon, Joseph; Sam, Chanel; Dickinson, Geoff; Robson, Ken; Leakey, Roger R B

2010-08-01

Phenotypic variation in heartwood and essential-oil characters of Santalum austrocaledonicum was assessed across eleven populations on seven islands of Vanuatu. Trees differed significantly in their percentage heartwood cross-sectional area and this varied independently of stem diameter. The concentrations of the four major essential-oil constituents (alpha-santalol, beta-santalol, (Z)-beta-curcumen-12-ol, and cis-nuciferol) of alcohol-extracted heartwood exhibited at least tenfold and continuous tree-to-tree variation. Commercially important components alpha- and beta-santalol found in individual trees ranged from 0.8-47% and 0-24.1%, respectively, across all populations, and significant (P<0.05) differences for each were found between individual populations. The Erromango population was unique in that the mean concentrations of its monocyclic ((Z)-beta-curcumen-12-ol and cis-nuciferol) sesquiterpenes exceeded those of its bi- and tricyclic (alpha- and beta-santalol) sesquiterpenes. Heartwood colour varied between trees and spanned 65 colour categories, but no identifiable relationships were found between heartwood colour and alpha- and beta-santalol, although a weak relationship was evident between colour saturation and total oil concentration. These results indicate that the heartwood colour is not a reliable predictive trait for oil quality. The results of this study highlight the knowledge gaps in fundamental understanding of heartwood biology in Santalum genus. The intraspecific variation in heartwood cross-sectional area, oil concentration, and oil quality traits is of considerable importance to the domestication of sandalwood and present opportunities for the development of highly superior S. austrocaledonicum cultivars that conform to the industry's International Standards used for S. album.

TryTransDB: A web-based resource for transport proteins in Trypanosomatidae.

PubMed

Sonar, Krushna; Kabra, Ritika; Singh, Shailza

2018-03-12

TryTransDB is a web-based resource that stores transport protein data which can be retrieved using a standalone BLAST tool. We have attempted to create an integrated database that can be a one-stop shop for the researchers working with transport proteins of Trypanosomatidae family. TryTransDB (Trypanosomatidae Transport Protein Database) is a web based comprehensive resource that can fire a BLAST search against most of the transport protein sequences (protein and nucleotide) from Trypanosomatidae family organisms. This web resource further allows to compute a phylogenetic tree by performing multiple sequence alignment (MSA) using CLUSTALW suite embedded in it. Also, cross-linking to other databases helps in gathering more information for a certain transport protein in a single website.

The construction and assessment of a statistical model for the prediction of protein assay data.

PubMed

Pittman, J; Sacks, J; Young, S Stanley

2002-01-01

The focus of this work is the development of a statistical model for a bioinformatics database whose distinctive structure makes model assessment an interesting and challenging problem. The key components of the statistical methodology, including a fast approximation to the singular value decomposition and the use of adaptive spline modeling and tree-based methods, are described, and preliminary results are presented. These results are shown to compare favorably to selected results achieved using comparitive methods. An attempt to determine the predictive ability of the model through the use of cross-validation experiments is discussed. In conclusion a synopsis of the results of these experiments and their implications for the analysis of bioinformatic databases in general is presented.

Minimum spanning tree filtering of correlations for varying time scales and size of fluctuations

NASA Astrophysics Data System (ADS)

Kwapień, Jarosław; Oświecimka, Paweł; Forczek, Marcin; DroŻdŻ, Stanisław

2017-05-01

Based on a recently proposed q -dependent detrended cross-correlation coefficient, ρq [J. Kwapień, P. Oświęcimka, and S. Drożdż, Phys. Rev. E 92, 052815 (2015), 10.1103/PhysRevE.92.052815], we generalize the concept of the minimum spanning tree (MST) by introducing a family of q -dependent minimum spanning trees (q MST s ) that are selective to cross-correlations between different fluctuation amplitudes and different time scales of multivariate data. They inherit this ability directly from the coefficients ρq, which are processed here to construct a distance matrix being the input to the MST-constructing Kruskal's algorithm. The conventional MST with detrending corresponds in this context to q =2 . In order to illustrate their performance, we apply the q MSTs to sample empirical data from the American stock market and discuss the results. We show that the q MST graphs can complement ρq in disentangling "hidden" correlations that cannot be observed in the MST graphs based on ρDCCA, and therefore, they can be useful in many areas where the multivariate cross-correlations are of interest. As an example, we apply this method to empirical data from the stock market and show that by constructing the q MSTs for a spectrum of q values we obtain more information about the correlation structure of the data than by using q =2 only. More specifically, we show that two sets of signals that differ from each other statistically can give comparable trees for q =2 , while only by using the trees for q ≠2 do we become able to distinguish between these sets. We also show that a family of q MSTs for a range of q expresses the diversity of correlations in a manner resembling the multifractal analysis, where one computes a spectrum of the generalized fractal dimensions, the generalized Hurst exponents, or the multifractal singularity spectra: the more diverse the correlations are, the more variable the tree topology is for different q 's. As regards the correlation structure of the stock market, our analysis exhibits that the stocks belonging to the same or similar industrial sectors are correlated via the fluctuations of moderate amplitudes, while the largest fluctuations often happen to synchronize in those stocks that do not necessarily belong to the same industry.

36 CFR 327.5 - Swimming.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Commander. (b) An international diver down, or inland diving flag must be displayed during underwater activities. (c) Diving, jumping or swinging from trees, bridges or other structures which cross or are...

36 CFR 327.5 - Swimming.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Commander. (b) An international diver down, or inland diving flag must be displayed during underwater activities. (c) Diving, jumping or swinging from trees, bridges or other structures which cross or are...

36 CFR 327.5 - Swimming.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Commander. (b) An international diver down, or inland diving flag must be displayed during underwater activities. (c) Diving, jumping or swinging from trees, bridges or other structures which cross or are...

On the Complexity of Duplication-Transfer-Loss Reconciliation with Non-Binary Gene Trees.

PubMed

Kordi, Misagh; Bansal, Mukul S

2017-01-01

Duplication-Transfer-Loss (DTL) reconciliation has emerged as a powerful technique for studying gene family evolution in the presence of horizontal gene transfer. DTL reconciliation takes as input a gene family phylogeny and the corresponding species phylogeny, and reconciles the two by postulating speciation, gene duplication, horizontal gene transfer, and gene loss events. Efficient algorithms exist for finding optimal DTL reconciliations when the gene tree is binary. However, gene trees are frequently non-binary. With such non-binary gene trees, the reconciliation problem seeks to find a binary resolution of the gene tree that minimizes the reconciliation cost. Given the prevalence of non-binary gene trees, many efficient algorithms have been developed for this problem in the context of the simpler Duplication-Loss (DL) reconciliation model. Yet, no efficient algorithms exist for DTL reconciliation with non-binary gene trees and the complexity of the problem remains unknown. In this work, we resolve this open question by showing that the problem is, in fact, NP-hard. Our reduction applies to both the dated and undated formulations of DTL reconciliation. By resolving this long-standing open problem, this work will spur the development of both exact and heuristic algorithms for this important problem.

[Diagnosing Low Health and Wood Borer Attacked Trees of Chinese Arborvitae by Using Thermography].

PubMed

Wang, Fei; Wu, De-jun; Zhai, Guo-feng; Zang, Li-peng

2015-12-01

Water and energy metabolism of plants is very important actions in their lives. Although the studies about these actions by using thermography were often reported, seldom were found in detecting the health status of forest trees. In this study, we increase the measurement accuracy and comparability of thermo-images by creating the difference indices. Based on it, we exam the water and energy status in stem of Chinese arborvitae (Platycladus orientalis (L.) Franco) by detecting the variance of far infrared spectrum between sap-wood and heart-wood of the cross-section of felling trees and the cores from an increment borer using thermography. The results indicate that the sap rate between sapwood and heartwood is different as the variance of the vigor of forest trees. Meanwhile, the image temperature of scale leaves from Chinese arborvitae trees with different vigor is also dissimilar. The far infrared spectrum more responds the sap status not the wood percentage in comparing to the area rate between sapwood and heartwood. The image temperature rate can be used in early determining the health status of Chinese arborvitae trees. The wood borers such as Phloeosinus aubei Perris and Semanotus bifasciatus Motschulsky are the pests which usually attack the low health trees, dying trees, wilted trees, felled trees and new cultivated trees. This measuring technique may be an important index to diagnose the health and vigor status after a large number of measurements for Chinese arborvitae trees. Therefore, there is potential to be an important index to check the tree vigor and pest damage status by using this technique. It will be a key in the tending and management of ecological and public Chinese arborvitae forest.

Climate Controls on Tree Growth Across Species and Sites in Northeastern Arizona

NASA Astrophysics Data System (ADS)

Schwan, M. R.; Guiterman, C. H.; Anchukaitis, K. J.

2016-12-01

Understanding how forests will respond to ongoing climate change is important for conservation and resource management. Conifer forests in the US Southwest are predicted to be particularly at risk from increased drought and higher temperatures projected to occur in the region. Tree-ring studies shed light on how trees respond to climate, but there remains considerable uncertainty as to which climate factors are most important, and which species are most at risk. Confounding climate and environmental factors, biological differences among species, and biogeography often complicate cross-species analysis. Here we present a multi-species, multivariate analysis of tree growth response to climate variability. We analyze data from three coexisting conifer tree species at two sites near Canyon de Chelly, Arizona. We use a high-resolution PRISM gridded climate dataset to determine the growth responses across species and sites to temperature and precipitation. We identify both common and differential responses in our data and use these to infer possible risks these forest communities may face under a changing climate.

Forest fire effects on transpiration: process modeling of sapwood area reduction

NASA Astrophysics Data System (ADS)

Michaletz, Sean; Johnson, Edward

2010-05-01

Transpiration is a hydrological process that is strongly affected by forest fires. In crown fires, canopy fine fuels (foliage, buds, and small branches) combust, which kills individual trees and stops transpiration of the entire stand. In surface fires (intensities ≤ 2500 kW m-1), however, effects on transpiration are less predictable becuase heat transfer from the passing fireline can injure or kill fine roots, leaves, and sapwood; post-fire transpiration of forest stands is thus governed by fire effects on individual tree water budgets. Here, we consider fire effects on cross-sectional sapwood area. A two-dimensional model of transient bole heating is used to estimate radial isotherms for a range of fireline intensities typical of surface fires. Isotherms are then used to drive three processes by which heat may reduce sapwood area: 1) necrosis of living cells in contact with xylem conduits, which prevents repair of natural embolism; 2) relaxation of viscoelastic conduit wall polymers (cellulose, hemicelloluse, and lignin), which reduces cross-sectional conduit area; and 3) boiling of metastable water under tension, which causes conduit embolism. Results show that these processes operate on different time scales, suggesting that fire effects on transpiration vary with time since fire. The model can be linked with a three-dimensional physical fire spread model to predict size-dependent effects on individual trees, which can be used to estimate scaling of individual tree and stand-level transpiration.

Improving the flash flood frequency analysis applying dendrogeomorphological evidences

NASA Astrophysics Data System (ADS)

Ruiz-Villanueva, V.; Ballesteros, J. A.; Bodoque, J. M.; Stoffel, M.; Bollschweiler, M.; Díez-Herrero, A.

2009-09-01

Flash floods are one of the natural hazards that cause major damages worldwide. Especially in Mediterranean areas they provoke high economic losses every year. In mountain areas with high stream gradients, floods events are characterized by extremely high flow and debris transport rates. Flash flood analysis in mountain areas presents specific scientific challenges. On one hand, there is a lack of information on precipitation and discharge due to a lack of spatially well distributed gauge stations with long records. On the other hand, gauge stations may not record correctly during extreme events when they are damaged or the discharge exceeds the recordable level. In this case, no systematic data allows improvement of the understanding of the spatial and temporal occurrence of the process. Since historic documentation is normally scarce or even completely missing in mountain areas, tree-ring analysis can provide an alternative approach. Flash floods may influence trees in different ways: (1) tilting of the stem through the unilateral pressure of the flowing mass or individual boulders; (2) root exposure through erosion of the banks; (3) injuries and scars caused by boulders and wood transported in the flow; (4) decapitation of the stem and resulting candelabra growth through the severe impact of boulders; (5) stem burial through deposition of material. The trees react to these disturbances with specific growth changes such as abrupt change of the yearly increment and anatomical changes like reaction wood or callus tissue. In this study, we sampled 90 cross sections and 265 increment cores of trees heavily affected by past flash floods in order to date past events and to reconstruct recurrence intervals in two torrent channels located in the Spanish Central System. The first study site is located along the Pelayo River, a torrent in natural conditions. Based on the external disturbances of trees and their geomorphological position, 114 Pinus pinaster (Ait.) influenced by flash flood events were sampled using an increment borer. For each tree sampled, additional information were recorded including the geographical position (GPS measure), the geomorphological situation based on a detailed geomorphological map, the social position within neighbouring trees, a description of the external disturbances and information on tree diameter, tree height and the position of the cores extracted. 265 cores were collected. In the laboratory, the 265 samples were analyzed using the standard methods: surface preparation, counting of tree rings as well as measuring of ring widths using a digital LINTAB positioning table and TSAP 4.6 software. Increment curves of the disturbed trees were then crossdated with a reference chronology in order to correct faulty tree-ring series derived from disturbed samples and to determine initiation of abrupt growth suppression or release. The age of the trees in this field site is between 50 and 100 years old. In the field most of the trees were tilted (93 %) and showed exposed roots (64 %). In the laboratory, growth suppressions were detected in 165 samples. Based on the number of trees showing disturbances, the intensity of the disturbance and the spatial distribution of the trees in the field, seven well represented events were dated for the last 50 years: 2005, 2000, 1996, 1976, 1973, 1966 and 1963. The second field site was a reach of 2 km length along the Arenal River, where the stream is channelized. Here stumps from previously felled trees could be analyzed directly in the field. 100 Alnus glutinosa (L.) Gaertn. and Fraxinus angustifolia (Vahl.) cross sections were investigated in order to date internal wounds. Different carpenter tools, sanding paper and magnifying glasses were used to count tree rings and to date the wounds in the field. In addition to the dating in the field, 22 cross sections were sampled and analyzed in the laboratory using the standard methods. The age of the trees ranges between 30 and 50 years. Based on the injuries dated in the field and in the laboratory, and based on the location of the trees, 8 main events were dated for the last 30 years: 2005, 2003, 2000, 1998, 1997, 1995, 1993 and 1978. Additional results are in progress, such as the amount of rainfall responsible for the triggering of the events, estimation of the magnitude, and the influence of the channelization in the case of the Arenal River. The strength of Dendrogeomorphology in flood analysis has been demonstrated, especially in areas where the lack of historical documents, rainfall and flow data limits the use of traditional methods.

Learning on Skiis.

ERIC Educational Resources Information Center

Neidich, Carole Louise

1980-01-01

Describes and illustrates wonders of the winter world encountered during a nature walk on cross-country skis through snow crystal examination, springtail observation, tree study, bird and plant identification, and animal track sighting. (NEC)

Relative Suffix Trees.

PubMed

Farruggia, Andrea; Gagie, Travis; Navarro, Gonzalo; Puglisi, Simon J; Sirén, Jouni

2018-05-01

Suffix trees are one of the most versatile data structures in stringology, with many applications in bioinformatics. Their main drawback is their size, which can be tens of times larger than the input sequence. Much effort has been put into reducing the space usage, leading ultimately to compressed suffix trees. These compressed data structures can efficiently simulate the suffix tree, while using space proportional to a compressed representation of the sequence. In this work, we take a new approach to compressed suffix trees for repetitive sequence collections, such as collections of individual genomes. We compress the suffix trees of individual sequences relative to the suffix tree of a reference sequence. These relative data structures provide competitive time/space trade-offs, being almost as small as the smallest compressed suffix trees for repetitive collections, and competitive in time with the largest and fastest compressed suffix trees.

Relative Suffix Trees

PubMed Central

Farruggia, Andrea; Gagie, Travis; Navarro, Gonzalo; Puglisi, Simon J; Sirén, Jouni

2018-01-01

Abstract Suffix trees are one of the most versatile data structures in stringology, with many applications in bioinformatics. Their main drawback is their size, which can be tens of times larger than the input sequence. Much effort has been put into reducing the space usage, leading ultimately to compressed suffix trees. These compressed data structures can efficiently simulate the suffix tree, while using space proportional to a compressed representation of the sequence. In this work, we take a new approach to compressed suffix trees for repetitive sequence collections, such as collections of individual genomes. We compress the suffix trees of individual sequences relative to the suffix tree of a reference sequence. These relative data structures provide competitive time/space trade-offs, being almost as small as the smallest compressed suffix trees for repetitive collections, and competitive in time with the largest and fastest compressed suffix trees. PMID:29795706

Weed management at ArborGen, South Carolina SuperTree Nursery

Treesearch

Mike Arnette

2009-01-01

Weed management is vital to producing healthy hardwood seedlings. Several methods are available to each nursery, and it is common knowledge that what works for one situation may not work for another. The weed control methods used in nursery beds of hardwood species at the South Carolina SuperTree Nursery (Blenheim) are listed below.

"Broken-Off Like Limbs from a Tree": Fractured Identity in Caryl Phillips's "Crossing the River (1993)"

ERIC Educational Resources Information Center

Labidi, Abid Larbi

2016-01-01

My major purpose in studying Caryl Phillips's widely acclaimed novel "Crossing the River" is to examine, through a close textual analysis, the severe identity crisis inflicted upon slaves under the three-century long slavery institution. I explore how slaves' tragic rift of separation from their African homelands led to a disastrous loss…

The reliability of determining age of red alder by ring counts

Treesearch

Dean S. DeBell; Boyd C. Wilson; Bernard T. Bormann

1978-01-01

Examination of cross-sections of 54 red alder trees from 14 stands of varying age and site conditions indicated that abnormal rings (false, partial, or missing) occur infrequently. Rings may be indistinct and ring counting must be done with great care, preferably on prepared surfaces (cross-sections or cores) and under magnification and good lighting. With such...

48 CFR 52.236-9 - Protection of Existing Vegetation, Structures, Equipment, Utilities, and Improvements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... preserve and protect all structures, equipment, and vegetation (such as trees, shrubs, and grass) on or... work required under this contract. The Contractor shall only remove trees when specifically authorized... trees are broken during contract performance, or by the careless operation of equipment, or by workmen...

Inventorying trees in agricultural landscapes: towards an accounting of working trees

Treesearch

C. H. Perry; C. W. Woodall; M.M. Schoeneberger

2005-01-01

Agroforestry plantings and other trees intentionally established in rural and urban areas are emerging as innovative management options for addressing resource issues and achieving landscape-level goals. An understanding of the contributions from these and future plantings would provide critical information to policy and program developers, and a comprehensive...

Inventorying trees in agricultural landscapes: toward an accounting of working trees

Treesearch

Carol H. Perry; Christopher W. Woodall; Michele M. Schoeneberger

2005-01-01

Agroforestry plantings and other trees intentionally established in rural and urban areas are emerging as innovative managemnt options for addressing resource issues and achieving landscape-level goals, An understanding of the contributions from these and future plantings would provide critical information to policy and program developers, and a comprehensive inventory...

48 CFR 52.236-9 - Protection of Existing Vegetation, Structures, Equipment, Utilities, and Improvements.

Code of Federal Regulations, 2012 CFR

2012-10-01

... preserve and protect all structures, equipment, and vegetation (such as trees, shrubs, and grass) on or... work required under this contract. The Contractor shall only remove trees when specifically authorized... trees are broken during contract performance, or by the careless operation of equipment, or by workmen...

48 CFR 52.236-9 - Protection of Existing Vegetation, Structures, Equipment, Utilities, and Improvements.

Code of Federal Regulations, 2014 CFR

2014-10-01

... preserve and protect all structures, equipment, and vegetation (such as trees, shrubs, and grass) on or... work required under this contract. The Contractor shall only remove trees when specifically authorized... trees are broken during contract performance, or by the careless operation of equipment, or by workmen...

48 CFR 52.236-9 - Protection of Existing Vegetation, Structures, Equipment, Utilities, and Improvements.

Code of Federal Regulations, 2013 CFR

2013-10-01

... preserve and protect all structures, equipment, and vegetation (such as trees, shrubs, and grass) on or... work required under this contract. The Contractor shall only remove trees when specifically authorized... trees are broken during contract performance, or by the careless operation of equipment, or by workmen...

48 CFR 52.236-9 - Protection of Existing Vegetation, Structures, Equipment, Utilities, and Improvements.

Code of Federal Regulations, 2011 CFR

2011-10-01

... preserve and protect all structures, equipment, and vegetation (such as trees, shrubs, and grass) on or... work required under this contract. The Contractor shall only remove trees when specifically authorized... trees are broken during contract performance, or by the careless operation of equipment, or by workmen...

The Tree Man: Robert Mazibuko's Story.

ERIC Educational Resources Information Center

Bloch, Joanne, Ed.

This book for beginning readers highlights Robert Mazibuko, the "Tree Man," who spent his life teaching people how to enrich the soil and plant vegetables and trees. Born in South Africa in 1904, he lived on a farm, learning to work with livestock, raise crops, and share with the community. In college, his professor of agriculture…

Interactions between river channel processes and riparian vegetation - an example from the Lužnice River, Czech Republic

NASA Astrophysics Data System (ADS)

Krejci, Lukas; Macka, Zdenek

2010-05-01

Riparian vegetation responds to hydrogemorphic processes and environmental changes and also controls these processes. Our study focuses on the interactions between woody riparian vegetation (live and dead trees) and river channel morphology on the example of three 1 km long reaches of the Lužnice River in southern Czech Republic. Here, we propose that despite spatial proximity, identical hydrological and sedimentological controls, three river reaches have different geomorphology due to varying character of riparian woody vegetation and different character and abundance of large in-stream wood (LW). Upstream, middle and downstream reaches vary markedly in channel dimensions (width, depth) and the present day rate of lateral erosion. Three reaches also show the different in-stream wood loads which are dependent mainly on the character of the riparian vegetation, and on the lateral activity of the channel. The highest wood load was recorded at the downstream reach with 102,162 m3/ha, the lowest at the middle reach 37,041 m3/ha, the upstream reach has load 81,370 m3/ha. Upper reach woody vegetation is the mixture of willow, alder, chokecherry and oak. The reach is only slightly sinuous with the moderate rate of incision and lateral erosion. The channel width and depth are 13 m and 2,1 m respectively, the mean cross section area is 27,3 m2. Erosion in the reach is slightly enhanced by the river training works upstream (canalisation, weir construction). Middle reach woody vegetation mostly consist of willow. Tree-tops often incline into the channel, thus, dissipating effectively the energy of the river flow. The reach is moderately sinuous and rather laterally stable. The channel width and depth are 10 m and 2,5 m respectively, the mean cross section area is 25 m2. The reach approximates the natural condition of the pristine river. The impact of river training works is minor only with the road bridge upstream. This reach in the most natural condition shows the lowest in-stream wood load and lowest rate of the present day bank erosion. Downstream reach woody vegetation is discontinuous, alternating with pastures. Riparian trees are the mixture of poplar, willow, alder and oak. The reach is highly sinuous with distinct meanders and laterally very dynamic. The channel width and depth are 15 m and 3,7 m respectively, the mean cross section area is 55,5 m2. The highest bank erosion was noted at the locations with pastures. The specific feature of this reach are fossil oak logs, which are exhumed from the alluvial sediments by the rapid lateral erosion. The enhanced incision and lateral erosion is the combined effect of riparian forest clearance and river training works (canalisation) downstream. The planform changes of the river since 1952 have been studied by analysis of the aerial images. It was derived that floodplain area of 12 450 m2, 16 318 m2 and 20 687 m2 was eroded, of which 10 465 m2, 8496 m2 and 10 733 m2 was wooded land at the upstream, middle and downstream reaches. We estimated that this rate of bank erosion delivered 644, 510 and 628 trees to the river channel since 1952. These numbers represent 390%, 1130% and 285% of the present day number of LW pieces in the river channel. Approximate turnover rates of LW can be estimated from these data. Present day rate of bank erosion and LW input is monitored at selected concave banks by repeated geodetic surveying. The Lužnice River has a sandy bed and LW modifies bed and bank morphology profoundly. We found that 33%, 29% and 36% of LW pieces caused localized erosion (pool formation) and 37%, 24% and 21 % caused local deposition at upstream, middle and downstream river reaches. The research was supported by Czech Science Foundation, grant no. 205/08/0926.

Multicast Routing and Wavelength Assignment with Shared Protection in Multi-Fiber WDM Mesh Networks: Optimal and Heuristic Solutions

NASA Astrophysics Data System (ADS)

Woradit, Kampol; Guyot, Matthieu; Vanichchanunt, Pisit; Saengudomlert, Poompat; Wuttisittikulkij, Lunchakorn

While the problem of multicast routing and wavelength assignment (MC-RWA) in optical wavelength division multiplexing (WDM) networks has been investigated, relatively few researchers have considered network survivability for multicasting. This paper provides an optimization framework to solve the MC-RWA problem in a multi-fiber WDM network that can recover from a single-link failure with shared protection. Using the light-tree (LT) concept to support multicast sessions, we consider two protection strategies that try to reduce service disruptions after a link failure. The first strategy, called light-tree reconfiguration (LTR) protection, computes a new multicast LT for each session affected by the failure. The second strategy, called optical branch reconfiguration (OBR) protection, tries to restore a logical connection between two adjacent multicast members disconnected by the failure. To solve the MC-RWA problem optimally, we propose an integer linear programming (ILP) formulation that minimizes the total number of fibers required for both working and backup traffic. The ILP formulation takes into account joint routing of working and backup traffic, the wavelength continuity constraint, and the limited splitting degree of multicast-capable optical cross-connects (MC-OXCs). After showing some numerical results for optimal solutions, we propose heuristic algorithms that reduce the computational complexity and make the problem solvable for large networks. Numerical results suggest that the proposed heuristic yields efficient solutions compared to optimal solutions obtained from exact optimization.

Solar and Climate Variation Relationships Analyzed from Chile Tree Ring Width Time Series (1587 - 1994 A.D.)

NASA Astrophysics Data System (ADS)

Rigozo, Nr; Nordemann, Djr; Faria, Hh; Echer, E.; Vieira, Lea; Prestes, A.

This work presents a study of the relations between solar and climate variations during the last four centuries by spectral analysis of tree ring index and sunspot number time series. Trees used for this study were Pilgerodendron cupressoides from Glaciar Pio XI, in Chile. The spectral analysis of tree ring index shows that 11, 22 and 80 year periodicities of the solar cycle were present in this tree ring data with 0.95 confidence level. This result suggests a solar modulation of climate variations, as recorded by the tree ring growth. Short-term variations, between 2 - 7 years, are also present in tree ring data. Therefore spectral analysis clearly shows that both, solar and climate factors, are recorded in the tree ring data.

Detailed characterization of Act d 12 and Act d 13 from kiwi seeds: implication in IgE cross-reactivity with peanut and tree nuts.

PubMed

Sirvent, S; Cantó, B; Gómez, F; Blanca, N; Cuesta-Herranz, J; Canto, G; Blanca, M; Rodríguez, R; Villalba, M; Palomares, O

2014-11-01

Act d 12 (11S globulin) and Act d 13 (2S albumin) are two novel relevant allergens from kiwi seeds that might be useful to improve the diagnostic sensitivity and the management of kiwifruit-allergic patients. To perform a comprehensive structural and immunological characterization of purified Act d 12 and Act d 13 from kiwi seeds. Sera from 55 well-defined kiwifruit-allergic patients were used. Act d 12 and Act d 13 were purified by chromatographic procedures. Circular dichroism, mass spectrometry, concanavalin A detection, immunoblotting, enzyme-linked immunosorbent assays, basophil activation tests, and IgE-inhibition experiments were used. Act d 12 and Act d 13 were purified from kiwi seeds to homogeneity by combining size-exclusion, ion-exchange, and RP-HPLC chromatographies. Both purified allergens preserve the structural integrity and display typical features of their homologous counterparts from the 11S globulin and 2S albumin protein families, respectively. These allergens are released from kiwi seeds after oral and gastric digestion of whole kiwifruit, demonstrating their bioavailability after ingestion. The allergens retain the capacity to bind serum IgE from kiwifruit-allergic patients, induce IgE cross-linking in effector-circulating basophils, and display in vitro IgE cross-reactivity with homologous counterparts from peanut and tree nuts. Purified Act d 12 and Act d 13 from kiwi seeds are well-defined molecules involved in in vitro IgE cross-reactivity with peanut and tree nuts. Their inclusion in component-resolved diagnosis of kiwifruit allergy might well contribute to improve the diagnostic sensitivity and the management of kiwifruit-allergic patients. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Temporal dynamics of stem expansion and contraction in savanna trees: withdrawal and recharge of stored water.

PubMed

Scholz, Fabian C; Bucci, Sandra J; Goldstein, Guillermo; Meinzer, Frederick C; Franco, Augusto C; Miralles-Wilhelm, Fernando

2008-03-01

Relationships between diel changes in stem expansion and contraction and discharge and refilling of stem water storage tissues were studied in six dominant Neotropical savanna (cerrado) tree species from central Brazil. Two stem tissues were studied, the active xylem or sapwood and the living tissues located between the cambium and the cork, made up predominantly of parenchyma cells (outer parenchyma). Outer parenchyma and sapwood density ranged from 320 to 410 kg m(-3) and from 420 to 620 kg m(-3), respectively, depending on the species. The denser sapwood tissues exhibited smaller relative changes in cross-sectional area per unit change in water potential compared with the outer parenchyma. Despite undergoing smaller relative changes in cross-sectional area, the sapwood released about 3.5 times as much stored water for a given change in area as the outer parenchyma. Cross-sectional area decreased earlier in the morning in the outer parenchyma than in the sapwood with lag times up to 30 min for most species. The relatively small lag time between dimensional changes of the two tissues suggested that they were hydraulically well connected. The initial morning increase in basal sap flow lagged about 10 to 130 min behind that of branch sap flow. Species-specific lag times between morning declines in branch and main stem cross-sectional area were a function of relative stem water storage capacity, which ranged from 16 to 31% of total diurnal water loss. Reliance on stored water to temporarily replace transpirational losses is one of the homeostatic mechanisms that constrain the magnitude of leaf water deficits in cerrado trees.

A simple and cost-effective method for cable root detection and extension measurement in estuary wetland forests

NASA Astrophysics Data System (ADS)

Vovides, Alejandra G.; Marín-Castro, Beatriz; Barradas, Guadalupe; Berger, Uta; López-Portillo, Jorge

2016-12-01

This work presents the development of a low-cost method to measure the length cable roots of black mangrove (Avicennia germinans) trees to define the boundaries of central part of the anchoring root system (CPRS) without the need to fully expose root systems. The method was tested to locate and measure the length shallow woody root systems. An ultrasonic Doppler fetal monitor (UD) and a stock of steel rods (SR) were used to probe root locations without removing sediments from the surface, measure their length and estimate root-soil plate dimensions. The method was validated by comparing measurements with root lengths taken through direct measurement of excavated cable roots and from root-soil plate radii (exposed root-soil material when a tree tips over) of five up-rooted trees with stem diameters (D130) ranging between 10 and 50 cm. The mean CPRS radius estimated with the use of the Doppler was directly correlated with tree stem diameter and was not significantly different from the root-soil plate mean radius measured from up-rooted trees or from CPRS approximated by digging trenches. Our method proved to be effective and reliable in following cable roots for large amounts of trees of both black and white mangrove trees. In a period of 40 days of work, three people were capable of measuring 648 roots belonging to 81 trees, out of which 37% were found grafted to other tree roots. This simple method can be helpful in following shallow root systems with minimal impact and help map root connection networks of grafted trees.

The influence of spruce on acidity and nutrient content in soils of Northern Taiga dwarf shrub-green moss spruce forests

NASA Astrophysics Data System (ADS)

Orlova, M. A.; Lukina, N. V.; Smirnov, V. E.; Artemkina, N. A.

2016-11-01

Presently, among the works considering the influence of forest trees on soil properties, the idea that spruce ( Picea abies) promotes the acidification of soils predominates. The aim of this work is to assess the effects of spruce trees of different ages and Kraft classes on the acidity and content of available nutrient compounds in the soils under boreal dwarf shrub-green moss spruce forests by the example of forest soils in the Kola Peninsula. The soils are typical iron-illuvial podzols (Albic Rustic Podzols (Arenic)). Three probable ways of developing soils under spruce forests with the moss-dwarf shrub ground cover are considered. The soils under windfall-soil complexes of flat mesodepressions present the initial status. The acidity of organic soil horizons from the initial stage of mesodepression overgrowth to the formation of adult trees changed nonlinearly: the soil acidity reached its maximum under the 30-40-year-old trees and decreased under the trees older than 100 years. The contents of nitrogen and available nutrients increased. The acidity of the mineral soil horizons under the trees at the ages of 110-135 and 190-220 years was comparable, but higher than that under the 30-40-year-old trees. The differences in the strength and trends of the trees' effect on the soils are explained by the age of spruce trees and their belonging to different Kraft classes.

iTREE: Long-term variability of tree growth in a changing environment - identifying physiological mechanisms using stable C and O isotopes in tree rings.

NASA Astrophysics Data System (ADS)

Siegwolf, R. T. W.; Buchmann, N.; Frank, D.; Joos, F.; Kahmen, A.; Treydte, K.; Leuenberger, M.; Saurer, M.

2012-04-01

Trees play are a critical role in the carbon cycle - their photosynthetic assimilation is one of the largest terrestrial carbon fluxes and their standing biomass represents the largest carbon pool of the terrestrial biosphere. Understanding how tree physiology and growth respond to long-term environmental change is pivotal to predict the magnitude and direction of the terrestrial carbon sink. iTREE is an interdisciplinary research framework to capitalize on synergies among leading dendroclimatologists, plant physiologists, isotope specialists, and global carbon cycle modelers with the objectives of reducing uncertainties related to tree/forest growth in the context of changing natural environments. Cross-cutting themes in our project are tree rings, stable isotopes, and mechanistic modelling. We will (i) establish a European network of tree-ring based isotope time-series to retrodict interannual to long-term tree physiological changes, (ii) conduct laboratory and field experiments to adapt a mechanistic isotope model to derive plant physiological variables from tree-ring isotopes, (iii) implement this model into a dynamic global vegetation model, and perform subsequent model-data validation exercises to refine model representation of plant physiological processes and (iv) attribute long-term variation in tree growth to plant physiological and environmental drivers, and identify how our refined knowledge revises predictions of the coupled carbon-cycle climate system. We will contribute to i) advanced quantifications of long-term variation in tree growth across Central Europe, ii) novel long-term information on key physiological processes that underlie variations in tree growth, and iii) improved carbon cycle models that can be employed to revise predictions of the coupled carbon-cycle climate system. Hence iTREE will significantly contribute towards a seamless understanding of the responses of terrestrial ecosystems to long-term environmental change, and ultimately help reduce uncertainties of the magnitude and direction of the past and future terrestrial carbon sink.

Networks and Spanning Trees: The Juxtaposition of Prüfer and Boruvka

ERIC Educational Resources Information Center

Lodder, Jerry

2014-01-01

This paper outlines a method for teaching topics in undergraduate mathematics or computer science via historical curricular modules. The contents of one module, "Networks and Spanning Trees," are discussed from the original work of Arthur Cayley, Heinz Prüfer, and Otakar Boruvka that motivates the enumeration and application of trees in…

Use of the "Tree" Analogy in Evolution Teaching by Biology Teachers

ERIC Educational Resources Information Center

Marcelos, Maria Fatima; Nagem, Ronaldo Luiz

2012-01-01

This work discusses the use of Darwin's "Tree of Life" as a didactic analogy and metaphor in teaching evolution. It investigates whether biology teachers of pupils from 17 to 18 years old know Darwin's text "Tree of Life". In addition, it examines whether those teachers systematically employ either the analogies present in that…

Proceedings of the fourth Lake States forest tree improvement conference

Treesearch

Lake States Forest Experiment Station

1960-01-01

The Lake States Forest Experiment Station is glad to facilitate the work of the Lake States Forest Tree Improvement Committee in encouraging and coordinating forest genetics activities in this region. We are happy, therefore, to publish this Proceedings of the Fourth Lake States Forest Tree Improvement Conference, as we did for the preceding three conferences in 1953,...

Red-cockaded woodpeckers vs rat snakes: the effectiveness of the resin barrier

Treesearch

D. Craig Rudolph; Howard Kyle; Richard N. Conner

1990-01-01

Red-cockaded Woodpeckers (Picoides borealis) excavate resin wells in the immediate vicinity of roost and nest cavity entrances. Resin wells are worked regularly, resulting in a copious and persistent resin flow that coats the tree trunk, especially below cavity entrances. Red-cockaded Woodpeckers also scale loose bark from cavity trees and closely adjacent trees....

Leafing-out date not indicative of growth rate in hybrid poplars

Treesearch

Harold F. Ford; Edward I. Sucoff

1961-01-01

In breeding trees for rapid growth, testing the progeny usually requires many years. To shorten the testing period, geneticists have tried to find characteristics in juvenile trees that would indicate mature-tree performance. With hybrid poplars (Populus spp.), work at the Northeastern Forest Experiment Station has shown that the thickness of bark on...

A benefit-cost analysis of ten tree species in Modesto, California, U.S.A

Treesearch

E.G. McPherson

2003-01-01

Tree work records for ten species were analyzed to estimate average annual management costs by dbh class for six activity areas. Average annual benefits were calculated by dbh class for each species with computer modeling. Average annual net benefits per tree were greatest for London plane (Platanus acerifolia) ($178.57), hackberry (...

Imprint of the Atlantic Multidecadal Oscillation on Tree-Ring Widths in Northeastern Asia since 1568

PubMed Central

Wang, Xiaochun; Brown, Peter M.; Zhang, Yanni; Song, Laiping

2011-01-01

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. PMID:21818380

Spatial statistical analysis of tree deaths using airborne digital imagery

NASA Astrophysics Data System (ADS)

Chang, Ya-Mei; Baddeley, Adrian; Wallace, Jeremy; Canci, Michael

2013-04-01

High resolution digital airborne imagery offers unprecedented opportunities for observation and monitoring of vegetation, providing the potential to identify, locate and track individual vegetation objects over time. Analytical tools are required to quantify relevant information. In this paper, locations of trees over a large area of native woodland vegetation were identified using morphological image analysis techniques. Methods of spatial point process statistics were then applied to estimate the spatially-varying tree death risk, and to show that it is significantly non-uniform. [Tree deaths over the area were detected in our previous work (Wallace et al., 2008).] The study area is a major source of ground water for the city of Perth, and the work was motivated by the need to understand and quantify vegetation changes in the context of water extraction and drying climate. The influence of hydrological variables on tree death risk was investigated using spatial statistics (graphical exploratory methods, spatial point pattern modelling and diagnostics).

SNP Identification from RNA Sequencing and Linkage Map Construction of Rubber Tree for Anchoring the Draft Genome

PubMed Central

Shearman, Jeremy R.; Sangsrakru, Duangjai; Jomchai, Nukoon; Ruang-areerate, Panthita; Sonthirod, Chutima; Naktang, Chaiwat; Theerawattanasuk, Kanikar; Tragoonrung, Somvong; Tangphatsornruang, Sithichoke

2015-01-01

Hevea brasiliensis, or rubber tree, is an important crop species that accounts for the majority of natural latex production. The rubber tree nuclear genome consists of 18 chromosomes and is roughly 2.15 Gb. The current rubber tree reference genome assembly consists of 1,150,326 scaffolds ranging from 200 to 531,465 bp and totalling 1.1 Gb. Only 143 scaffolds, totalling 7.6 Mb, have been placed into linkage groups. We have performed RNA-seq on 6 varieties of rubber tree to identify SNPs and InDels and used this information to perform target sequence enrichment and high throughput sequencing to genotype a set of SNPs in 149 rubber tree offspring from a cross between RRIM 600 and RRII 105 rubber tree varieties. We used this information to generate a linkage map allowing for the anchoring of 24,424 contigs from 3,009 scaffolds, totalling 115 Mb or 10.4% of the published sequence, into 18 linkage groups. Each linkage group contains between 319 and 1367 SNPs, or 60 to 194 non-redundant marker positions, and ranges from 156 to 336 cM in length. This linkage map includes 20,143 of the 69,300 predicted genes from rubber tree and will be useful for mapping studies and improving the reference genome assembly. PMID:25831195

SNP identification from RNA sequencing and linkage map construction of rubber tree for anchoring the draft genome.

PubMed

Shearman, Jeremy R; Sangsrakru, Duangjai; Jomchai, Nukoon; Ruang-Areerate, Panthita; Sonthirod, Chutima; Naktang, Chaiwat; Theerawattanasuk, Kanikar; Tragoonrung, Somvong; Tangphatsornruang, Sithichoke

2015-01-01

Hevea brasiliensis, or rubber tree, is an important crop species that accounts for the majority of natural latex production. The rubber tree nuclear genome consists of 18 chromosomes and is roughly 2.15 Gb. The current rubber tree reference genome assembly consists of 1,150,326 scaffolds ranging from 200 to 531,465 bp and totalling 1.1 Gb. Only 143 scaffolds, totalling 7.6 Mb, have been placed into linkage groups. We have performed RNA-seq on 6 varieties of rubber tree to identify SNPs and InDels and used this information to perform target sequence enrichment and high throughput sequencing to genotype a set of SNPs in 149 rubber tree offspring from a cross between RRIM 600 and RRII 105 rubber tree varieties. We used this information to generate a linkage map allowing for the anchoring of 24,424 contigs from 3,009 scaffolds, totalling 115 Mb or 10.4% of the published sequence, into 18 linkage groups. Each linkage group contains between 319 and 1367 SNPs, or 60 to 194 non-redundant marker positions, and ranges from 156 to 336 cM in length. This linkage map includes 20,143 of the 69,300 predicted genes from rubber tree and will be useful for mapping studies and improving the reference genome assembly.

Widespread Amazon forest tree mortality from a single cross-basin squall line event

NASA Astrophysics Data System (ADS)

Negrón-Juárez, Robinson I.; Chambers, Jeffrey Q.; Guimaraes, Giuliano; Zeng, Hongcheng; Raupp, Carlos F. M.; Marra, Daniel M.; Ribeiro, Gabriel H. P. M.; Saatchi, Sassan S.; Nelson, Bruce W.; Higuchi, Niro

2010-08-01

Climate change is expected to increase the intensity of extreme precipitation events in Amazonia that in turn might produce more forest blowdowns associated with convective storms. Yet quantitative tree mortality associated with convective storms has never been reported across Amazonia, representing an important additional source of carbon to the atmosphere. Here we demonstrate that a single squall line (aligned cluster of convective storm cells) propagating across Amazonia in January, 2005, caused widespread forest tree mortality and may have contributed to the elevated mortality observed that year. Forest plot data demonstrated that the same year represented the second highest mortality rate over a 15-year annual monitoring interval. Over the Manaus region, disturbed forest patches generated by the squall followed a power-law distribution (scaling exponent α = 1.48) and 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. Basin-wide, potential tree mortality from this one event was 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. Storm intensity is expected to increase with a warming climate, which would result in additional tree mortality and carbon release to the atmosphere, with the potential to further warm the climate system.

A cross sectional study on hand-arm vibration syndrome among a group of tree fellers in a tropical environment.

PubMed

Su, Anselm Ting; Maeda, Setsuo; Fukumoto, Jin; Miyai, Nobuyuki; Isahak, Marzuki; Yoshioka, Atsushi; Nakajima, Ryuichi; Bulgiba, Awang; Miyashita, Kazuhisa

2014-01-01

This study aimed to explore the clinical characteristics of hand arm vibration syndrome (HAVS) in a group of tree fellers in a tropical environment. We examined all tree fellers and selected control subjects in a logging camp of central Sarawak for vibration exposure and presence of HAVS symptoms utilizing vibrotactile perception threshold test (VPT) and cold water provocation test (CWP). None of the subjects reported white finger. The tree fellers reported significantly higher prevalence of finger coldness as compared to the control subjects (OR=10.32, 95%CI=1.21-87.94). A lower finger skin temperature, longer fingernail capillary return time and higher VPT were observed among the tree fellers as compared to the control subjects in all fingers (effect size >0.5). The VPT following CWP of the tree fellers was significantly higher (repeated measures ANOVA p=0.002, partial η(2)=0.196) than the control subject. The A (8) level was associated with finger tingling, numbness and dullness (effect size=0.983) and finger coldness (effect size=0.524) among the tree fellers. Finger coldness and finger tingling, numbness and dullness are important symptoms for HAVS in tropical environment that may indicate vascular and neurological damage due to hand-transmitted vibration exposure.

On fractal properties of arterial trees.

PubMed

Zamir, M

1999-04-21

The question of fractal properties of arterial trees is considered in light of data from the extensive tree structure of the right coronary artery of a human heart. Because of the highly non-uniform structure of this tree, the study focuses on the purely geometrical rather than statistical aspects of fractal properties. The large number of arterial bifurcations comprising the tree were found to have a mixed degree of asymmetry at all levels of the tree, including the depth of the tree where it has been generally supposed that they would be symmetrical. Cross-sectional area ratios of daughter to parent vessels were also found to be highly mixed at all levels, having values both above and below 1.0, rather than consistently above as has been generally supposed in the past. Calculated values of the power law index which describes the theoretical relation between the diameters of the three vessel segments at an arterial bifurcation were found to range far beyond the two values associated with the cube and square laws, and not clearly favoring one or the other. On the whole the tree structure was found to have what we have termed "pseudo-fractal" properties, in the sense that vessels of different calibers displayed the same branching pattern but with a range of values of the branching parameters. The results suggest that a higher degree of fractal character, one in which the branching parameters are constant throughout the tree structure, is unlikely to be attained in non-uniform vascular structures. Copyright 1999 Academic Press.

Long-term growth trends of red spruce and fraser fir at Mt. Rogers, Virginia and Mt. Mitchell, North Carolina

Treesearch

J.C.G. Goelz; Thomas E. Burk; Shepard M. Zedaker

1999-01-01

Cross-sectional area growth and height growth of Fraser fir and red spruce trees growing in Virginia and North Carolina were analyzed to identify possible long-term growth trends. Cross-sectional area growth provided no evidence of growth decline. The individual discs were classified according to parameter estimates of the growth trend equation. The predominant pattern...

Fire and vegetation dynamics in the Cross Timbers forests of south-central North America

Treesearch

Steve W. Hallgren; Ryan D. DeSantis; Jesse A. Burton

2012-01-01

The vegetation of the Cross Timbers forests was maintained for thousands of years by fire; the historic fire return interval was likely 1 to 10 years. Fire suppression over the past century led to a doubling of stand basal area, increased diversity of tree species, reduced dominance of oak, and increased mesic species intolerant of fire. Dendrochronological studies...

Association between split selection instability and predictive error in survival trees.

PubMed

Radespiel-Tröger, M; Gefeller, O; Rabenstein, T; Hothorn, T

2006-01-01

To evaluate split selection instability in six survival tree algorithms and its relationship with predictive error by means of a bootstrap study. We study the following algorithms: logrank statistic with multivariate p-value adjustment without pruning (LR), Kaplan-Meier distance of survival curves (KM), martingale residuals (MR), Poisson regression for censored data (PR), within-node impurity (WI), and exponential log-likelihood loss (XL). With the exception of LR, initial trees are pruned by using split-complexity, and final trees are selected by means of cross-validation. We employ a real dataset from a clinical study of patients with gallbladder stones. The predictive error is evaluated using the integrated Brier score for censored data. The relationship between split selection instability and predictive error is evaluated by means of box-percentile plots, covariate and cutpoint selection entropy, and cutpoint selection coefficients of variation, respectively, in the root node. We found a positive association between covariate selection instability and predictive error in the root node. LR yields the lowest predictive error, while KM and MR yield the highest predictive error. The predictive error of survival trees is related to split selection instability. Based on the low predictive error of LR, we recommend the use of this algorithm for the construction of survival trees. Unpruned survival trees with multivariate p-value adjustment can perform equally well compared to pruned trees. The analysis of split selection instability can be used to communicate the results of tree-based analyses to clinicians and to support the application of survival trees.

The role of hybridization in facilitating tree invasion

PubMed Central

2017-01-01

Abstract Hybridization events can generate additional genetic diversity upon which natural selection can act and at times enhance invasiveness of the species. Invasive tree species are a growing ecological concern worldwide, and some of these invasions involve hybridization events pre- or post-introduction. There are 20 hybrid invasive tree taxa in 15 genera (11 plant families) discussed here. When reported, abundance of hybrids comprised 10–100 % of an invasion, the remainder being parental taxa. In seven hybrid taxa, researchers identified phenotypes that may make hybrids better invaders. Twelve hybrid tree taxa involved introgression and more hybrids involved all non-native taxa than native × non-native taxa. Three hybrid tree taxa were the result of intentional crosses, and all hybrid taxa involved intentional introduction of either one or more parental taxon or the hybrid itself. The knowledge gaps present in some hybrid tree taxa can weaken our effectiveness in predicting and controlling invasions, as hybrids can add a level of complexity to an invasion by being morphologically cryptic, causing genetic pollution of a native parental taxon, presenting novel genotypes for which there may not be coevolved biological control agents, or evolving adaptive traits through increased genetic variation. PMID:28028055

Predictability of the future development of aggressive behavior of cranial dural arteriovenous fistulas based on decision tree analysis.

PubMed

Satomi, Junichiro; Ghaibeh, A Ammar; Moriguchi, Hiroki; Nagahiro, Shinji

2015-07-01

The severity of clinical signs and symptoms of cranial dural arteriovenous fistulas (DAVFs) are well correlated with their pattern of venous drainage. Although the presence of cortical venous drainage can be considered a potential predictor of aggressive DAVF behaviors, such as intracranial hemorrhage or progressive neurological deficits due to venous congestion, accurate statistical analyses are currently not available. Using a decision tree data mining method, the authors aimed at clarifying the predictability of the future development of aggressive behaviors of DAVF and at identifying the main causative factors. Of 266 DAVF patients, 89 were eligible for analysis. Under observational management, 51 patients presented with intracranial hemorrhage/infarction during the follow-up period. The authors created a decision tree able to assess the risk for the development of aggressive DAVF behavior. Evaluated by 10-fold cross-validation, the decision tree's accuracy, sensitivity, and specificity were 85.28%, 88.33%, and 80.83%, respectively. The tree shows that the main factor in symptomatic patients was the presence of cortical venous drainage. In its absence, the lesion location determined the risk of a DAVF developing aggressive behavior. Decision tree analysis accurately predicts the future development of aggressive DAVF behavior.

Population Structure of the Bacterial Pathogen Xylella fastidiosa among Street Trees in Washington D.C.

PubMed Central

Harris, Jordan Lee; Balci, Yilmaz

2015-01-01

Bacterial leaf scorch, associated with the bacterial pathogen Xylella fastidiosa, is a widely established and problematic disease of landscape ornamentals in Washington D.C. A multi-locus sequence typing analysis was performed using 10 housekeeping loci for X. fastidiosa strains in order to better understand the epidemiology of leaf scorch disease in this municipal environment. Samples were collected from 7 different tree species located throughout the District of Columbia, consisting of 101 samples of symptomatic and asymptomatic foliage from 84 different trees. Five strains of the bacteria were identified. Consistent with prior data, these strains were host specific, with only one strain associated with members of the red oak family, one strain associated with American elm, one strain associated with American sycamore, and two strains associated with mulberry. Strains found for asymptomatic foliage were the same as strains from the symptomatic foliage on individual trees. Cross transmission of the strains was not observed at sites with multiple species of infected trees within an approx. 25 m radius of one another. X. fastidiosa strain specificity observed for each genus of tree suggests a highly specialized host-pathogen relationship. PMID:25815838

Activity classification using realistic data from wearable sensors.

PubMed

Pärkkä, Juha; Ermes, Miikka; Korpipää, Panu; Mäntyjärvi, Jani; Peltola, Johannes; Korhonen, Ilkka

2006-01-01

Automatic classification of everyday activities can be used for promotion of health-enhancing physical activities and a healthier lifestyle. In this paper, methods used for classification of everyday activities like walking, running, and cycling are described. The aim of the study was to find out how to recognize activities, which sensors are useful and what kind of signal processing and classification is required. A large and realistic data library of sensor data was collected. Sixteen test persons took part in the data collection, resulting in approximately 31 h of annotated, 35-channel data recorded in an everyday environment. The test persons carried a set of wearable sensors while performing several activities during the 2-h measurement session. Classification results of three classifiers are shown: custom decision tree, automatically generated decision tree, and artificial neural network. The classification accuracies using leave-one-subject-out cross validation range from 58 to 97% for custom decision tree classifier, from 56 to 97% for automatically generated decision tree, and from 22 to 96% for artificial neural network. Total classification accuracy is 82 % for custom decision tree classifier, 86% for automatically generated decision tree, and 82% for artificial neural network.

Population structure of the bacterial pathogen Xylella fastidiosa among street trees in Washington D.C.

PubMed

Harris, Jordan Lee; Balci, Yilmaz

2015-01-01

Bacterial leaf scorch, associated with the bacterial pathogen Xylella fastidiosa, is a widely established and problematic disease of landscape ornamentals in Washington D.C. A multi-locus sequence typing analysis was performed using 10 housekeeping loci for X. fastidiosa strains in order to better understand the epidemiology of leaf scorch disease in this municipal environment. Samples were collected from 7 different tree species located throughout the District of Columbia, consisting of 101 samples of symptomatic and asymptomatic foliage from 84 different trees. Five strains of the bacteria were identified. Consistent with prior data, these strains were host specific, with only one strain associated with members of the red oak family, one strain associated with American elm, one strain associated with American sycamore, and two strains associated with mulberry. Strains found for asymptomatic foliage were the same as strains from the symptomatic foliage on individual trees. Cross transmission of the strains was not observed at sites with multiple species of infected trees within an approx. 25 m radius of one another. X. fastidiosa strain specificity observed for each genus of tree suggests a highly specialized host-pathogen relationship.

VHF/UHF imagery and RCS measurements of ground targets in forested terrain

NASA Astrophysics Data System (ADS)

Gatesman, Andrew J.; Beaudoin, Christopher J.; Giles, Robert H.; Waldman, Jerry; Nixon, William E.

2002-08-01

The monostatic VV and HH-polarized radar signatures of several targets and trees have been measured at foliage penetration frequencies (VHF/UHF) by using 1/35th scale models and an indoor radar range operating at X-band. An array of high-fidelity scale model ground vehicles and test objects as well as scaled ground terrain and trees have been fabricated for the study. Radar measurement accuracy has been confirmed by comparing the signature of a test object with a method of moments radar cross section prediction code. In addition to acquiring signatures of targets located on a smooth, dielectric ground plane, data have also been acquired with targets located in simulated wooded terrain that included scaled tree trunks and tree branches. In order to assure the correct backscattering behavior, all dielectric properties of live tree wood and moist soil were scaled properly to match the complex dielectric constant of the full-scale materials. The impact of the surrounding tree clutter on the VHF/UHF radar signatures of ground vehicles was accessed. Data were processed into high-resolution, polar-formatted ISAR imagery and signature comparisons are made between targets in open-field and forested scenarios.

Cellular modelling of secondary radial growth in conifer trees: application to Pinus radiata (D. Don).

PubMed

Forest, Loïc; Demongeot, Jacques; Demongeota, Jacques

2006-05-01

The radial growth of conifer trees proceeds from the dynamics of a merismatic tissue called vascular cambium or cambium. Cambium is a thin layer of active proliferating cells. The purpose of this paper was to model the main characteristics of cambial activity and its consecutive radial growth. Cell growth is under the control of the auxin hormone indole-3-acetic. The model is composed of a discrete part, which accounts for cellular proliferation, and a continuous part involving the transport of auxin. Cambium is modeled in a two-dimensional cross-section by a cellular automaton that describes the set of all its constitutive cells. Proliferation is defined as growth and division of cambial cells under neighbouring constraints, which can eliminate some cells from the cambium. The cell-growth rate is determined from auxin concentration, calculated with the continuous model. We studied the integration of each elementary cambial cell activity into the global coherent movement of macroscopic morphogenesis. Cases of normal and abnormal growth of Pinus radiata (D. Don) are modelled. Abnormal growth includes deformed trees where gravity influences auxin transport, producing heterogeneous radial growth. Cross-sectional microscopic views are also provided to validate the model's hypothesis and results.

Performance of Seven Tree Breeding Strategies Under Conditions of Inbreeding Depression.

PubMed

Wu, Harry X; Hallingbäck, Henrik R; Sánchez, Leopoldo

2016-01-06

In the domestication and breeding of tree species that suffer from inbreeding depression (ID), the long-term performance of different breeding strategies is poorly known. Therefore, seven tree breeding strategies including single population, subline, selfing, and nucleus breeding were simulated using a multi-locus model with additive, partial, and complete dominance allele effects, and with intermediate, U-shaped, and major allele distributions. The strategies were compared for genetic gain, inbreeding accumulation, capacity to show ID, the frequencies and fixations of unfavorable alleles, and genetic variances in breeding and production populations. Measured by genetic gain of production population, the nucleus breeding and the single breeding population with mass selection strategies were equal or superior to subline and single breeding population with within-family selection strategies in all simulated scenarios, in spite of their higher inbreeding coefficients. Inbreeding and cross-breeding effectively decreased ID and could in some scenarios produce genetic gains during the first few generations. However, in all scenarios, considerable fixation of unfavorable alleles rendered the purging performance of selfing and cross-breeding strategies ineffective, and resulted in substantial inferiority in comparison to the other strategies in the long-term. Copyright © 2016 Wu et al.

Performance of Seven Tree Breeding Strategies Under Conditions of Inbreeding Depression

PubMed Central

Wu, Harry X.; Hallingbäck, Henrik R.; Sánchez, Leopoldo

2016-01-01

In the domestication and breeding of tree species that suffer from inbreeding depression (ID), the long-term performance of different breeding strategies is poorly known. Therefore, seven tree breeding strategies including single population, subline, selfing, and nucleus breeding were simulated using a multi-locus model with additive, partial, and complete dominance allele effects, and with intermediate, U-shaped, and major allele distributions. The strategies were compared for genetic gain, inbreeding accumulation, capacity to show ID, the frequencies and fixations of unfavorable alleles, and genetic variances in breeding and production populations. Measured by genetic gain of production population, the nucleus breeding and the single breeding population with mass selection strategies were equal or superior to subline and single breeding population with within-family selection strategies in all simulated scenarios, in spite of their higher inbreeding coefficients. Inbreeding and cross-breeding effectively decreased ID and could in some scenarios produce genetic gains during the first few generations. However, in all scenarios, considerable fixation of unfavorable alleles rendered the purging performance of selfing and cross-breeding strategies ineffective, and resulted in substantial inferiority in comparison to the other strategies in the long-term. PMID:26739644

Dendroecological opportunities to shift and cross disciplinary boundaries

NASA Astrophysics Data System (ADS)

Buentgen, Ulf

2017-04-01

In this 'solicited' talk, I will firstly navigate through some of the most influential dendroecological/-climatological advancements of roughly the last decade. Afterwards, I will outline pending challenges in modern tree-ring research, including the ongoing involvement of (quantitative) wood anatomical materials, methods and perspectives. Finally, I will provide several examples of how dendroecological approaches might indeed be able to contribute towards identifying and shifting research frontiers, as well as crossing disciplinary boundaries; not only within the vast field of natural sciences but also with the humanities. While presenting an array of timely case studies, with all of them being centered on either tree-ring data or associated techniques, this talk will comprise multiple aspects of archaeology, astronomy, biology, ecology, epidemiology, history, mycology and volcanology. In so doing, I hope to stimulate discussion on the potential and limitations of state-of-the-art tree-ring research across various spatiotemporal scales of resolution, which may range from the cell to the hemisphere and from the day to the Holocene. Despite its overview character, this talk will place emphases on utilizing big datasets, on valuing Russia's scientific landscape, on performing high-resolution radiocarbon measurements, and on linking volcanic activity, climate variability and human history.

Using trees to compute approximate solutions to ordinary differential equations exactly

NASA Technical Reports Server (NTRS)

Grossman, Robert

1991-01-01

Some recent work is reviewed which relates families of trees to symbolic algorithms for the exact computation of series which approximate solutions of ordinary differential equations. It turns out that the vector space whose basis is the set of finite, rooted trees carries a natural multiplication related to the composition of differential operators, making the space of trees an algebra. This algebraic structure can be exploited to yield a variety of algorithms for manipulating vector fields and the series and algebras they generate.

Dendritic tree extraction from noisy maximum intensity projection images in C. elegans.

PubMed

Greenblum, Ayala; Sznitman, Raphael; Fua, Pascal; Arratia, Paulo E; Oren, Meital; Podbilewicz, Benjamin; Sznitman, Josué

2014-06-12

Maximum Intensity Projections (MIP) of neuronal dendritic trees obtained from confocal microscopy are frequently used to study the relationship between tree morphology and mechanosensory function in the model organism C. elegans. Extracting dendritic trees from noisy images remains however a strenuous process that has traditionally relied on manual approaches. Here, we focus on automated and reliable 2D segmentations of dendritic trees following a statistical learning framework. Our dendritic tree extraction (DTE) method uses small amounts of labelled training data on MIPs to learn noise models of texture-based features from the responses of tree structures and image background. Our strategy lies in evaluating statistical models of noise that account for both the variability generated from the imaging process and from the aggregation of information in the MIP images. These noisy models are then used within a probabilistic, or Bayesian framework to provide a coarse 2D dendritic tree segmentation. Finally, some post-processing is applied to refine the segmentations and provide skeletonized trees using a morphological thinning process. Following a Leave-One-Out Cross Validation (LOOCV) method for an MIP databse with available "ground truth" images, we demonstrate that our approach provides significant improvements in tree-structure segmentations over traditional intensity-based methods. Improvements for MIPs under various imaging conditions are both qualitative and quantitative, as measured from Receiver Operator Characteristic (ROC) curves and the yield and error rates in the final segmentations. In a final step, we demonstrate our DTE approach on previously unseen MIP samples including the extraction of skeletonized structures, and compare our method to a state-of-the art dendritic tree tracing software. Overall, our DTE method allows for robust dendritic tree segmentations in noisy MIPs, outperforming traditional intensity-based methods. Such approach provides a useable segmentation framework, ultimately delivering a speed-up for dendritic tree identification on the user end and a reliable first step towards further morphological characterizations of tree arborization.

[Cross reactions between pollens and vegetable food allergens].

PubMed

Pauli, G; Metz-Favre, C

2013-04-01

The association of food allergies and pollinosis are numerous, implicating tree, grass and weed pollens on one hand and on the other, several plant foods which after ingestion can induce an oral syndrome or more severe reactions such as urticaria, Quincke's edema, asthma and even anaphylactic shock. The molecular basis of cross reactions between pollens and vegetable food allergens is increasingly understood. The principal allergens involved are those of the Bet v 1 family, and profilins found in all pollens as well as in many fruits and vegetables; these two groups of allergens are denatured by high temperatures and by gastric enzymes, in contrast to LTP, which is only found in weeds and some tree pollens. Other molecules can be involved in cross reactions such as Bet v 6 (an isoflavone reductase), 1 beta glucanases and thaumatine-like proteins. Inhibition experiments confirmed that the epitopes responsible for primary sensitization come mainly from pollen allergens; the cross-reactive molecular allergen is related to the geographic environment of the patients. The practical aspects of managing these patients are underlined: explanations of co-sensitization, explanations for the lack of efficacy of some extracts, usefulness of a molecular diagnosis obtained either by CAP or microarray, prediction of severe clinical reactions induced by specific molecular allergens and the effectiveness of pollen immunotherapy on the cross-related food allergy. Copyright © 2013 SPLF. Published by Elsevier Masson SAS. All rights reserved.

Using Redwood Tree Ring Chronologies to Obtain the Long-View on California's Coastal Climate

NASA Astrophysics Data System (ADS)

Dawson, T. E.; Roden, J. S.; Voelker, S. L.; Johnstone, J. A.; Ambrose, A.

2014-12-01

Coast redwood (Sequoia sempervirens) occupies a long and narrow range at the land-sea interface from the southern Big Bur region to the California-Oregon boarder. Since mature trees can live in excess of 2000 years, using the interannual variability in the oxygen and carbon stable isotope composition of tree rings obtained from trees growing in different parts of the redwood range holds the potential for obtaining a long-term record of California's coastal climate, including the history of temperatures, low cloud / fog, rainfall and associated climatic drivers of their variation. We analyzed the oxygen and carbon stable isotope composition of tree ring cellulose from both tree cores and whole cross-sectional slabs and compared these data to several regional climate indicies and to published growth chronologies to obtain the long-view on California's coastal climate. Several highlights will be presented and discussed. These include: (1) redwoods faithfully record water sources they use in the oxygen stable isotope composition of their tree ring cellulose; (2) these is both strong watershed- and regional-scale coherence; (3) redwood tree ring carbon isotope composition shows its strongest correlations to tree water status, stand-scale humidity, and at the regional scale to what we term "summer precipitation" anomalies (lack of rain with presence of fog); also (4) that carbon stable isotope composition is very sensitive to within tree and stand microclimate while oxygen stable isotope composition seems to be sensitive to topographic site factors like slope position and proximity to riparian / gully habitats; (5) multivariate climatic analyses reveal that summertime drought recorded in the isotope excursions are most strongly linked to atmospheric circulation anomalies; and (6) that redwood tree rings and their isotope composition provide great potential for reconstructing high-resolution paleo-climate along the California coast.

Climatic signals in stable carbon isotope ratios of Juniper and Oak tree rings from northern Iran

NASA Astrophysics Data System (ADS)

Foroozan, Zeynab; Pourtahmasi, Kambiz; Bräuning, Achim

2018-06-01

Stable isotope ratios in tree rings are increasingly used as palaeoclimatic archive and ecophysiological indicator. We used cross-dated tree-ring series from different tree functional types, i.e. the evergreen conifer Juniperus polycarpus and the deciduous broadleaved Quercus macranthera. The samples were collected from Chaharbagh Gorgon forest in northern Iran, where oaks and junipers grow on north-facing and south-facing slopes, respectively. We extracted α-cellulose from the whole wood of annually separated tree rings and evaluated their potential for palaeoclimate reconstructions by examining the relationships between variations of δ13C in tree-ring cellulose and climate parameters. Based on tree-ring δ13C, we calculated intrinsic water use efficiency (iWUE) and evaluated changes in water availability at the study site over the past 50 years. We found significant negative relationships between tree-ring δ13C values in oak and juniper and precipitation in April and spring (only in junipers), while no significant correlations of tree-ring δ13C with temperature occurred. A strong negative relationship between tree-ring δ13C and summer Palmer Drought Severity Index (PDSI) was found at the drier site, indicating that juniper growing on south-facing slopes is a better indicator of drought stress in semiarid environments. A continuous increase in iWUE in both species was observed. δ13C variations in both species reflect the combined influence of climate and local site conditions. The interplay between climatic conditions and species behavior determines the inter-annual δ13C patterns of oak and juniper trees. Due to its more enriched mean δ13C (i.e., less negative average δ13C) and its higher climatic sensitivity, juniper is a more suitable proxy for paleoclimatic reconstructions in northern Iran.

Changes in sapwood permeability and anatomy with tree age and height in the broad-leaved evergreen species Eucalyptus regnans.

PubMed

England, Jacqueline R; Attiwill, Peter M

2007-08-01

Increases in plant size and structural complexity with increasing age have important implications for water flow through trees. Water supply to the crown is influenced by both the cross-sectional area and the permeability of sapwood. It has been hypothesized that hydraulic conductivity within sapwood increases with age. We investigated changes in sapwood permeability (k) and anatomy with tree age and height in the broad-leaved evergreen species Eucalyptus regnans F. Muell. Sapwood was sampled at breast height from trees ranging from 8 to 240 years old, and at three height positions on the main stem of 8-year-old trees. Variation in k was not significant among sampling height positions in young trees. However, k at breast height increased with tree age. This was related to increases in both vessel frequency and vessel diameter, resulting in a greater proportion of sapwood being occupied by vessel lumina. Sapwood hydraulic conductivity (the product of k and sapwood area) also increased with increasing tree age. However, at the stand level, there was a decrease in forest sapwood hydraulic conductivity with increasing stand age, because of a decrease in the number of trees per hectare. Across all ages, there were significant relationships between k and anatomy, with individual anatomical characteristics explaining 33-62% of the variation in k. There was also strong agreement between measured k and permeability predicted by the Hagen-Poiseuille equation. The results support the hypothesis of an increase in sapwood permeability at breast height with age. Further measurements are required to confirm this result at other height positions in older trees. The significance of tree-level changes in sapwood permeability for stand-level water relations is discussed.

On metric structure of ultrametric spaces

NASA Astrophysics Data System (ADS)

Nechaev, S. K.; Vasilyev, O. A.

2004-03-01

In our work we have reconsidered the old problem of diffusion at the boundary of an ultrametric tree from a 'number theoretic' point of view. Namely, we use the modular functions (in particular, the Dedekind eegr-function) to construct the 'continuous' analogue of the Cayley tree isometrically embedded in the Poincaré upper half-plane. Later we work with this continuous Cayley tree as with a standard function of a complex variable. In the framework of our approach, the results of Ogielsky and Stein on dynamics in ultrametric spaces are reproduced semi-analytically or semi-numerically. The speculation on the new 'geometrical' interpretation of replica n rarr 0 limit is proposed.

Growth patterns of red pine on fine-textured soils.

Treesearch

David H. Alban; Donald H. Prettyman; Gary J. Brand

1987-01-01

Compares growth of 28- to 49-year-old red pine plantations on sandy and fine-textured soils. Red pine growing on these two contrasting soils did not differ in bole form, live crown ratio, or mortality, and tree growth predicted by models (STEMS and REDPINE) developed from trees growing on sandy soils worked equally well for trees growing on fine-textured soils.

Proceedings of the sixth Lake States forest tree improvement conference

Treesearch

Paul O. Rudolf

1964-01-01

In April of 1953 the Lake States Forest Tree Improvement Committee was formed, following a regional conference sponsored by the Lake States Forest Experiment Station. Since that time there has been a marked increase in the amount of tree improvement work done in this region, and the Committee has performed a valuable service in encouraging and coordinating such...

The Probabilistic Thinking of Primary School Pupils in Cyprus: The Case of Tree Diagrams

ERIC Educational Resources Information Center

Lamprianou, Iasonas; Lamprianou, Thekla Afantiti

2003-01-01

In this research work we explored the nature of 9-12 year old pupils' responses to probabilistic problems with tree diagrams. It was found that a large percentage of pupils failed to respond correctly even to very simple problems that demanded the identification of "possible routes/paths" in figures with tree diagrams/mazes. The results…

The effects of rainfall partitioning and evapotranspiration on the temporal and spatial variation of soil water content in a Mediterranean agroforestry system

NASA Astrophysics Data System (ADS)

Biel, C.; Molina, A.; Aranda, X.; Llorens, P.; Savé, R.

2012-04-01

Tree plantation for wood production has been proposed to mitigate CO2-related climate change. Although these agroforestry systems can contribute to maintain the agriculture in some areas placed between rainfed crops and secondary forests, water scarcity in Mediterranean climate could restrict its growth, and their presence will affect the water balance. Tree plantations management (species, plant density, irrigation, etc), hence, can be used to affect the water balance, resulting in water availability improvement and buffering of the water cycle. Soil water content and meteorological data are widely used in agroforestry systems as indicators of vegetation water use, and consequently to define water management. However, the available information of ecohydrological processes in this kind of ecosystem is scarce. The present work studies how the temporal and spatial variation of soil water content is affected by transpiration and interception loss fluxes in a Mediterranean rainfed plantation of cherry tree (Prunus avium) located in Caldes de Montbui (Northeast of Spain). From May till December 2011, rainfall partitioning, canopy transpiration, soil water content and meteorological parameters were continuously recorded. Rainfall partitioning was measured in 6 trees, with 6 automatic rain recorders for throughfall and 1 automatic rain recorder for stemflow per tree. Transpiration was monitored in 12 nearby trees by means of heat pulse sap flow sensors. Soil water content was also measured at three different depths under selected trees and at two depths between rows without tree cover influence. This work presents the relationships between rainfall partitioning, transpiration and soil water content evolution under the tree canopy. The effect of tree cover on the soil water content dynamics is also analyzed.

Impacts of age-dependent tree sensitivity and dating approaches on dendrogeomorphic time series of landslides

NASA Astrophysics Data System (ADS)

Šilhán, Karel; Stoffel, Markus

2015-05-01

Different approaches and thresholds have been utilized in the past to date landslides with growth ring series of disturbed trees. Past work was mostly based on conifer species because of their well-defined ring boundaries and the easy identification of compression wood after stem tilting. More recently, work has been expanded to include broad-leaved trees, which are thought to produce less and less evident reactions after landsliding. This contribution reviews recent progress made in dendrogeomorphic landslide analysis and introduces a new approach in which landslides are dated via ring eccentricity formed after tilting. We compare results of this new and the more conventional approaches. In addition, the paper also addresses tree sensitivity to landslide disturbance as a function of tree age and trunk diameter using 119 common beech (Fagus sylvatica L.) and 39 Crimean pine (Pinus nigra ssp. pallasiana) trees growing on two landslide bodies. The landslide events reconstructed with the classical approach (reaction wood) also appear as events in the eccentricity analysis, but the inclusion of eccentricity clearly allowed for more (162%) landslides to be detected in the tree-ring series. With respect to tree sensitivity, conifers and broad-leaved trees show the strongest reactions to landslides at ages comprised between 40 and 60 years, with a second phase of increased sensitivity in P. nigra at ages of ca. 120-130 years. These phases of highest sensitivities correspond with trunk diameters at breast height of 6-8 and 18-22 cm, respectively (P. nigra). This study thus calls for the inclusion of eccentricity analyses in future landslide reconstructions as well as for the selection of trees belonging to different age and diameter classes to allow for a well-balanced and more complete reconstruction of past events.

Current and Future Carbon Budgets of Tropical Rain Forest: A Cross Scale Analysis. Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oberbauer, S. F.

2004-01-16

The goal of this project was to make a first assessment of the major carbon stocks and fluxes and their climatic determinants in a lowland neotropical rain forest, the La Selva Biological Station, Costa Rica. Our research design was based on the concurrent use of several of the best available approaches, so that data could be cross-validated. A major focus of our effort was to combine meteorological studies of whole-forest carbon exchange (eddy flux), with parallel independent measurements of key components of the forest carbon budget. The eddy flux system operated from February 1998 to February 2001. To obtain fieldmore » data that could be scaled up to the landscape level, we monitored carbon stocks, net primary productivity components including tree growth and mortality, litterfall, woody debris production, root biomass, and soil respiration in a series of replicated plots stratified across the major environmental gradients of the forest. A second major focus of this project was on the stocks and changes of carbon in the soil. We used isotope studies and intensive monitoring to investigate soil organic stocks and the climate-driven variation of soil respiration down the soil profile, in a set of six 4m deep soil shafts stratified across the landscape. We measured short term tree growth, climate responses of sap flow, and phenology in a suite of ten canopy trees to develop individual models of tree growth to daytime weather variables.« less

Quantifying pruning impacts on olive tree architecture and annual canopy growth by using UAV-based 3D modelling.

PubMed

Jiménez-Brenes, F M; López-Granados, F; de Castro, A I; Torres-Sánchez, J; Serrano, N; Peña, J M

2017-01-01

Tree pruning is a costly practice with important implications for crop harvest and nutrition, pest and disease control, soil protection and irrigation strategies. Investigations on tree pruning usually involve tedious on-ground measurements of the primary tree crown dimensions, which also might generate inconsistent results due to the irregular geometry of the trees. As an alternative to intensive field-work, this study shows a innovative procedure based on combining unmanned aerial vehicle (UAV) technology and advanced object-based image analysis (OBIA) methodology for multi-temporal three-dimensional (3D) monitoring of hundreds of olive trees that were pruned with three different strategies (traditional, adapted and mechanical pruning). The UAV images were collected before pruning, after pruning and a year after pruning, and the impacts of each pruning treatment on the projected canopy area, tree height and crown volume of every tree were quantified and analyzed over time. The full procedure described here automatically identified every olive tree on the orchard and computed their primary 3D dimensions on the three study dates with high accuracy in the most cases. Adapted pruning was generally the most aggressive treatment in terms of the area and volume (the trees decreased by 38.95 and 42.05% on average, respectively), followed by trees under traditional pruning (33.02 and 35.72% on average, respectively). Regarding the tree heights, mechanical pruning produced a greater decrease (12.15%), and these values were minimal for the other two treatments. The tree growth over one year was affected by the pruning severity and by the type of pruning treatment, i.e., the adapted-pruning trees experienced higher growth than the trees from the other two treatments when pruning intensity was low (<10%), similar to the traditionally pruned trees at moderate intensity (10-30%), and lower than the other trees when the pruning intensity was higher than 30% of the crown volume. Combining UAV-based images and an OBIA procedure allowed measuring tree dimensions and quantifying the impacts of three different pruning treatments on hundreds of trees with minimal field work. Tree foliage losses and annual canopy growth showed different trends as affected by the type and severity of the pruning treatments. Additionally, this technology offers valuable geo-spatial information for designing site-specific crop management strategies in the context of precision agriculture, with the consequent economic and environmental benefits.

Office of Legacy Management Decision Tree for Solar Photovoltaic Projects - 13317

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elmer, John; Butherus, Michael; Barr, Deborah L.

2013-07-01

To support consideration of renewable energy power development as a land reuse option, the DOE Office of Legacy Management (LM) and the National Renewable Energy Laboratory (NREL) established a partnership to conduct an assessment of wind and solar renewable energy resources on LM lands. From a solar capacity perspective, the larger sites in the western United States present opportunities for constructing solar photovoltaic (PV) projects. A detailed analysis and preliminary plan was developed for three large sites in New Mexico, assessing the costs, the conceptual layout of a PV system, and the electric utility interconnection process. As a result ofmore » the study, a 1,214-hectare (3,000-acre) site near Grants, New Mexico, was chosen for further study. The state incentives, utility connection process, and transmission line capacity were key factors in assessing the feasibility of the project. LM's Durango, Colorado, Disposal Site was also chosen for consideration because the uranium mill tailings disposal cell is on a hillside facing south, transmission lines cross the property, and the community was very supportive of the project. LM worked with the regulators to demonstrate that the disposal cell's long-term performance would not be impacted by the installation of a PV solar system. A number of LM-unique issues were resolved in making the site available for a private party to lease a portion of the site for a solar PV project. A lease was awarded in September 2012. Using a solar decision tree that was developed and launched by the EPA and NREL, LM has modified and expanded the decision tree structure to address the unique aspects and challenges faced by LM on its multiple sites. The LM solar decision tree covers factors such as land ownership, usable acreage, financial viability of the project, stakeholder involvement, and transmission line capacity. As additional sites are transferred to LM in the future, the decision tree will assist in determining whether a solar PV project is feasible on the new sites. (authors)« less

Tree-ring-based drought reconstruction in the Iberian Range (east of Spain) since 1694

NASA Astrophysics Data System (ADS)

Tejedor, Ernesto; de Luis, Martín; Cuadrat, José María; Esper, Jan; Saz, Miguel Ángel

2016-03-01

Droughts are a recurrent phenomenon in the Mediterranean basin with negative consequences for society, economic activities, and natural systems. Nevertheless, the study of drought recurrence and severity in Spain has been limited so far due to the relatively short instrumental period. In this work, we present a reconstruction of the standardized precipitation index (SPI) for the Iberian Range. Growth variations and climatic signals within the network are assessed developing a correlation matrix and the data combined to a single chronology integrating 336 samples from 169 trees of five different pine species distributed throughout the province of Teruel. The new chronology, calibrated against regional instrumental climatic data, shows a high and stable correlation with the July SPI integrating moisture conditions over 12 months forming the basis for a 318-year drought reconstruction. The climate signal contained in this reconstruction is highly significant ( p < 0.05) and spatially robust over the interior areas of Spain located above 1000 meters above sea level (masl). According to our SPI reconstruction, seven substantially dry and five wet periods are identified since the late seventeenth century considering ≥±1.76 standard deviations. Besides these, 36 drought and 28 pluvial years were identified. Some of these years, such as 1725, 1741, 1803, and 1879, are also revealed in other drought reconstructions in Romania and Turkey, suggesting that coherent larger-scale synoptic patterns drove these extreme deviations. Since regional drought deviations are also retained in historical documents, the tree-ring-based reconstruction presented here will allow us to cross-validate drought frequency and magnitude in a highly vulnerable region.

Tree-ring-based drought reconstruction in the Iberian Range (east of Spain) since 1694.

PubMed

Tejedor, Ernesto; de Luis, Martín; Cuadrat, José María; Esper, Jan; Saz, Miguel Ángel

2016-03-01

Droughts are a recurrent phenomenon in the Mediterranean basin with negative consequences for society, economic activities, and natural systems. Nevertheless, the study of drought recurrence and severity in Spain has been limited so far due to the relatively short instrumental period. In this work, we present a reconstruction of the standardized precipitation index (SPI) for the Iberian Range. Growth variations and climatic signals within the network are assessed developing a correlation matrix and the data combined to a single chronology integrating 336 samples from 169 trees of five different pine species distributed throughout the province of Teruel. The new chronology, calibrated against regional instrumental climatic data, shows a high and stable correlation with the July SPI integrating moisture conditions over 12 months forming the basis for a 318-year drought reconstruction. The climate signal contained in this reconstruction is highly significant (p < 0.05) and spatially robust over the interior areas of Spain located above 1000 meters above sea level (masl). According to our SPI reconstruction, seven substantially dry and five wet periods are identified since the late seventeenth century considering ≥±1.76 standard deviations. Besides these, 36 drought and 28 pluvial years were identified. Some of these years, such as 1725, 1741, 1803, and 1879, are also revealed in other drought reconstructions in Romania and Turkey, suggesting that coherent larger-scale synoptic patterns drove these extreme deviations. Since regional drought deviations are also retained in historical documents, the tree-ring-based reconstruction presented here will allow us to cross-validate drought frequency and magnitude in a highly vulnerable region.

Seasonality on the rainfall partitioning of a fast-growing tree plantation under Mediterranean conditions

NASA Astrophysics Data System (ADS)

molina, antonio; llorens, pilar; biel, carme

2014-05-01

Studies on rainfall interception in fast-growing tree plantations are less numerous than those in natural forests. Trees in these plantations are regularly distributed, and the canopy cover is clumped but changes quickly, resulting on high variability in the volume and composition of water that reach the soil. In addition, irrigation supply is normally required in semiarid areas to get optimal wood production; consequently, knowing rainfall interception and its yearly evolution is crucial to manage the irrigation scheme properly. This work studies the rainfall partitioning seasonality in a cherry tree (Prunus avium) plantation orientated to timber production under Mediterranean conditions. The monitoring design started on March 2012 and consists of a set of 58 throughfall tipping buckets randomly distributed (based on a 1x1 m2 grid) in a plot of 128 m2 with 8 trees. Stemflow is measured in all the trees with 2 tipping buckets and 6 accumulative collectors. Canopy cover is regularly measured throughout the study period, in leaf and leafless periods, by mean of sky-orientated photographs taken 50 cm above the center of each tipping bucket. Others tree biometrics are also measured such as diameter and leaf area index. Meteorological conditions are measured at 2 m above the forest cover. This work presents the first analyses describing the rainfall partitioning and its dependency on canopy cover, distance to tree and meteorological conditions. The modified Gash' model for rainfall interception in dispersed vegetation is also preliminary evaluated.

Models relating stem growth to crown length dynamics: application to loblolly pine and Norway spruce

Treesearch

Harry T. Valentine; Annikki Makela; Edward J. Green; Ralph L. Amateis; Harri Makinen; Mark J. Ducey

2012-01-01

We derive and analyze a model that relates the growth rate of cross-sectional area ('csa') at any height on the central stem of a tree to crown-length dynamics. The derivation is based, in part, on assumptions that (a) active csa on the central stem relates allometrically to the length of crown above the cross section, and (b) inactive csa is proportional to...

Quercus stellata growth and stand characteristics in the Quercus stellata-Quercus marilandica forest type in the Cross Timbers region of Central Oklahoma

Treesearch

James F. Rosson

1994-01-01

The author reports a baseline forest survey of Central and West Oklahoma to obtain tree and stand growth rates for harvest sustainability, standing volume estimates for biomass assessments, and stand structure to provide other pertinent data for exploring management options. This report focused on the Quercus stellata-Quercus marilandica forest type in the Cross...

Evaluating the predictability of distance race performance in NCAA cross country and track and field from high school race times in the United States.

PubMed

Brusa, Jamie L

2017-12-30

Successful recruiting for collegiate track & field athletes has become a more competitive and essential component of coaching. This study aims to determine the relationship between race performances of distance runners at the United States high school and National Collegiate Athletic Association (NCAA) levels. Conditional inference classification tree models were built and analysed to predict the probability that runners would qualify for the NCAA Division I National Cross Country Meet and/or the East or West NCAA Division I Outdoor Track & Field Preliminary Round based on their high school race times in the 800 m, 1600 m, and 3200 m. Prediction accuracies of the classification trees ranged from 60.0 to 76.6 percent. The models produced the most reliable estimates for predicting qualifiers in cross country, the 1500 m, and the 800 m for females and cross country, the 5000 m, and the 800 m for males. NCAA track & field coaches can use the results from this study as a guideline for recruiting decisions. Additionally, future studies can apply the methodological foundations of this research to predicting race performances set at different metrics, such as national meets in other countries or Olympic qualifications, from previous race data.

Molecular basis of angiosperm tree architecture.

PubMed

Hollender, Courtney A; Dardick, Chris

2015-04-01

The architecture of trees greatly impacts the productivity of orchards and forestry plantations. Amassing greater knowledge on the molecular genetics that underlie tree form can benefit these industries, as well as contribute to basic knowledge of plant developmental biology. This review describes the fundamental components of branch architecture, a prominent aspect of tree structure, as well as genetic and hormonal influences inferred from studies in model plant systems and from trees with non-standard architectures. The bulk of the molecular and genetic data described here is from studies of fruit trees and poplar, as these species have been the primary subjects of investigation in this field of science. No claim to original US Government works. New Phytologist © 2014 New Phytologist Trust.

Multicasting in Wireless Communications (Ad-Hoc Networks): Comparison against a Tree-Based Approach

NASA Astrophysics Data System (ADS)

Rizos, G. E.; Vasiliadis, D. C.

2007-12-01

We examine on-demand multicasting in ad hoc networks. The Core Assisted Mesh Protocol (CAMP) is a well-known protocol for multicast routing in ad-hoc networks, generalizing the notion of core-based trees employed for internet multicasting into multicast meshes that have much richer connectivity than trees. On the other hand, wireless tree-based multicast routing protocols use much simpler structures for determining route paths, using only parent-child relationships. In this work, we compare the performance of the CAMP protocol against the performance of wireless tree-based multicast routing protocols, in terms of two important factors, namely packet delay and ratio of dropped packets.

Chronic back pain and associated work and non-work variables among farmworkers from Starr County, Texas.

PubMed

Shipp, Eva M; Cooper, Sharon P; del Junco, Deborah J; Delclos, George L; Burau, Keith D; Tortolero, Susan; Whitworth, Ryan E

2009-01-01

This study estimated the prevalence of chronic back pain among migrant farmworker family members and identified associated work and non-work variables. Migrant farmworkers (n = 390 from 267 families) from Starr County, Texas were interviewed in their home once a year for 2 years. The original survey included items measuring demographics, smoking, sleep, farm work, and chronic back pain. For this cross-sectional analysis, multi-level logistic regression was used to identify associated work and other variables associated with chronic back pain while accounting for intraclass correlations due to repeated measures and multiple family members. The prevalence of chronic back pain during the last migration season ranged from 9.5% among the youngest children to 33.3% among mothers. Variables significantly associated with chronic back pain were age (odds ratio [OR], 1.03, per year increase), depressive symptoms while migrating (OR, 8.72), fewer than 8 hours of sleep at home in Starr County (OR, 2.26), fairly bad/very bad quality of sleep while migrating (OR, 3.25), sorting crops at work (OR, 0.18), and working tree crops (OR, 11.72). The role of work exposures, depressive symptoms, and sleep in chronic back pain among farmworkers warrants further examination. Refinements in outcome and exposure assessments are also needed given the lack of a standardized case definition and the variety of tasks and crops involved in farm work in the United States.

Data needs for tree removal crash modification factors on Arizona state highways.

DOT National Transportation Integrated Search

2016-07-01

The Arizona Department of Transportation (ADOT) Roadway Departure Safety Implementation Plan (RDSIP) has : identified tree removal as a feasible countermeasure to reduce roadway departure crash frequency or severity. : Previous ADOT work has identifi...

Force of habit: shrubs, trees and contingent evolution of wood anatomical diversity using Croton (Euphorbiaceae) as a model system

Treesearch

Rafael Arévalo; Benjamin W. van Ee; Ricarda Riina; Paul E. Berry; Alex C. Wiedenhoeft

2017-01-01

Background and Aims Wood is a major innovation of land plants, and is usually a central component of the body plan for two major plant habits: shrubs and trees. Wood anatomical syndromes vary between shrubs and trees, but no prior work has explicitly evaluated the contingent evolution of wood anatomical diversity in the context...

Implementing municipal tree planting: Los Angeles million tree initiative

Treesearch

S. Pincetl

2010-01-01

Urban forests are increasingly being seen as an important infrastructure that can help cities remediate their environmental impacts. This work reports on the first steps in implementing a million tree program in Los Angeles and the ways such a biogenic—living—infrastructure has been approached. Numbers of studies have been done to quantify the benefits of urban forests...

Increment-borer methods for determining fire history in coniferous forests

Treesearch

Stephen W. Barrett; Stephen F. Arno

1988-01-01

Describes use of increment borers for interpreting fire history in coniferous forests. These methods are intended for use in wildernesses, parks, and other natural areas where sawing cross-sections from fire-scarred trees is prohibited.

Anapole dark matter annihilation into photons

NASA Astrophysics Data System (ADS)

Latimer, David C.

2017-05-01

In models of anapole dark matter (DM), the DM candidate is a Majorana fermion whose primary interaction with standard model (SM) particles is through an anapole coupling to off-shell photons. As such, at tree-level, anapole DM undergoes p-wave annihilation into SM charged fermions via a virtual photon. But, generally, Majorana fermions are polarizable, coupling to two real photons. This fact admits the possibility that anapole DM can annihilate into two photons in an s-wave process. Using an explicit model, we compute both the tree-level and diphoton contributions to the anapole DM annihilation cross section. Depending on model parameters, the s-wave process can either rival or be dwarfed by the p-wave contribution to the total annihilation cross section. Subjecting the model to astrophysical upper bounds on the s-wave annihilation mode, we rule out the model with large s-wave annihilation.

In situ assessment of the velocity of carbon transfer by tracing 13 C in trunk CO2 efflux after pulse labelling: variations among tree species and seasons.

PubMed

Dannoura, Masako; Maillard, Pascale; Fresneau, Chantal; Plain, Caroline; Berveiller, Daniel; Gerant, Dominique; Chipeaux, Christophe; Bosc, Alexandre; Ngao, Jérôme; Damesin, Claire; Loustau, Denis; Epron, Daniel

2011-04-01

Phloem is the main pathway for transferring photosynthates belowground. In situ(13) C pulse labelling of trees 8-10 m tall was conducted in the field on 10 beech (Fagus sylvatica) trees, six sessile oak (Quercus petraea) trees and 10 maritime pine (Pinus pinaster) trees throughout the growing season. Respired (13) CO2 from trunks was tracked at different heights using tunable diode laser absorption spectrometry to determine time lags and the velocity of carbon transfer (V). The isotope composition of phloem extracts was measured on several occasions after labelling and used to estimate the rate constant of phloem sap outflux (kP ). Pulse labelling together with high-frequency measurement of the isotope composition of trunk CO2 efflux is a promising tool for studying phloem transport in the field. Seasonal variability in V was predicted in pine and oak by bivariate linear regressions with air temperature and soil water content. V differed among the three species consistently with known differences in phloem anatomy between broadleaf and coniferous trees. V increased with tree diameter in oak and beech, reflecting a nonlinear increase in volumetric flow with increasing bark cross-sectional area, which suggests changes in allocation pattern with tree diameter in broadleaf species. Discrepancies between V and kP indicate vertical changes in functional phloem properties. © 2011 The Authors. New Phytologist © 2011 New Phytologist Trust.

An efficient protocol for tissue sampling and DNA isolation from the stem bark of Leguminosae trees.

PubMed

Novaes, R M L; Rodrigues, J G; Lovato, M B

2009-02-03

Traditionally, molecular studies of plant species have used leaves as the source of DNA. However, sampling leaves from tall tree species can be quite difficult and expensive. We developed a sequence of procedures for using stem bark as a source of DNA from Leguminosae trees of the Atlantic Forest and the Cerrado. Leguminosae is an important species-rich family in these two highly diverse and endangered biomes. A modified CTAB protocol for DNA isolation is described, and details of the procedures for sampling and storage of the bark are given. The procedures were initially developed for three species, and then their applicability for 15 other species was evaluated. DNA of satisfactory quality was obtained from the bark of all species. The amounts of DNA obtained from leaves were slightly higher than from bark samples, while its purity was the same. Storing the bark frozen or by drying in silica gel yielded similar results. Polymerase chain reaction amplification worked for both plastid and nuclear genomes. This alternative for isolating DNA from bark samples of trees facilitates field work with these tree species.

The Trees that surround us

NASA Astrophysics Data System (ADS)

Costa, M. E. G.; Rodrigues, M. A. S.

2012-04-01

In our school the activities linked with sciences are developed in a partnership with other school subjects. Interdisciplinary projects are always valued from beginning to end of a project. It is common for teachers of different areas to work together in a Science project. Research of English written articles is very important not only for the development of our students' scientific literacy but also as a way of widening knowledge and a view on different perspectives of life instead of being limited to research of any articles in Portuguese language. In this study we are going to collect data about the predominant tree species in the region, especially the invasive trees from the acacia species, the native tree species and the commercial species. We are going to study the reasons for the appearance of each species and draw a chart of soil occupation in the council. This chart will also allow the study of the distribution and use of land for each tree species. This research work is the first stage for a contribution to warn the town council of the dangers of the invasive species to the future economy of the council.

Aerodynamic effects of trees on pollutant concentration in street canyons.

PubMed

Buccolieri, Riccardo; Gromke, Christof; Di Sabatino, Silvana; Ruck, Bodo

2009-09-15

This paper deals with aerodynamic effects of avenue-like tree planting on flow and traffic-originated pollutant dispersion in urban street canyons by means of wind tunnel experiments and numerical simulations. Several parameters affecting pedestrian level concentration are investigated, namely plant morphology, positioning and arrangement. We extend our previous work in this novel aspect of research to new configurations which comprise tree planting of different crown porosity and stand density, planted in two rows within a canyon of street width to building height ratio W/H=2 with perpendicular approaching wind. Sulfur hexafluoride was used as tracer gas to model the traffic emissions. Complementary to wind tunnel experiments, 3D numerical simulations were performed with the Computational Fluid Dynamics (CFD) code FLUENT using a Reynolds Stress turbulence closure for flow and the advection-diffusion method for concentration calculations. In the presence of trees, both measurements and simulations showed considerable larger pollutant concentrations near the leeward wall and slightly lower concentrations near the windward wall in comparison with the tree-less case. Tree stand density and crown porosity were found to be of minor importance in affecting pollutant concentration. On the other hand, the analysis indicated that W/H is a more crucial parameter. The larger the value of W/H the smaller is the effect of trees on pedestrian level concentration regardless of tree morphology and arrangement. A preliminary analysis of approaching flow velocities showed that at low wind speed the effect of trees on concentrations is worst than at higher speed. The investigations carried out in this work allowed us to set up an appropriate CFD modelling methodology for the study of the aerodynamic effects of tree planting in street canyons. The results obtained can be used by city planners for the design of tree planting in the urban environment with regard to air quality issues.

Classification tree for the assessment of sedentary lifestyle among hypertensive.

PubMed

Castelo Guedes Martins, Larissa; Venícios de Oliveira Lopes, Marcos; Gomes Guedes, Nirla; Paixão de Menezes, Angélica; de Oliveira Farias, Odaleia; Alves Dos Santos, Naftale

2016-04-01

To develop a classification tree of clinical indicators for the correct prediction of the nursing diagnosis "Sedentary lifestyle" (SL) in people with high blood pressure (HTN). A cross-sectional study conducted in an outpatient care center specializing in high blood pressure and Mellitus diabetes located in northeastern Brazil. The sample consisted of 285 people between 19 and 59 years old diagnosed with high blood pressure and was applied an interview and physical examination, obtaining socio-demographic information, related factors and signs and symptoms that made the defining characteristics for the diagnosis under study. The tree was generated using the CHAID algorithm (Chi-square Automatic Interaction Detection). The construction of the decision tree allowed establishing the interactions between clinical indicators that facilitate a probabilistic analysis of multiple situations allowing quantify the probability of an individual presenting a sedentary lifestyle. The tree included the clinical indicator Choose daily routine without exercise as the first node. People with this indicator showed a probability of 0.88 of presenting the SL. The second node was composed of the indicator Does not perform physical activity during leisure, with 0.99 probability of presenting the SL with these two indicators. The predictive capacity of the tree was established at 69.5%. Decision trees help nurses who care HTN people in decision-making in assessing the characteristics that increase the probability of SL nursing diagnosis, optimizing the time for diagnostic inference.

Multiclassifier system with hybrid learning applied to the control of bioprosthetic hand.

PubMed

Kurzynski, Marek; Krysmann, Maciej; Trajdos, Pawel; Wolczowski, Andrzej

2016-02-01

In this paper the problem of recognition of the intended hand movements for the control of bio-prosthetic hand is addressed. The proposed method is based on recognition of electromiographic (EMG) and mechanomiographic (MMG) biosignals using a multiclassifier system (MCS) working in a two-level structure with a dynamic ensemble selection (DES) scheme and original concepts of competence function. Additionally, feedback information coming from bioprosthesis sensors on the correct/incorrect classification is applied to the adjustment of the combining mechanism during MCS operation through adaptive tuning competences of base classifiers depending on their decisions. Three MCS systems operating in decision tree structure and with different tuning algorithms are developed. In the MCS1 system, competence is uniformly allocated to each class belonging to the group indicated by the feedback signal. In the MCS2 system, the modification of competence depends on the node of decision tree at which a correct/incorrect classification is made. In the MCS3 system, the randomized model of classifier and the concept of cross-competence are used in the tuning procedure. Experimental investigations on the real data and computer-simulated procedure of generating feedback signals are performed. In these investigations classification accuracy of the MCS systems developed is compared and furthermore, the MCS systems are evaluated with respect to the effectiveness of the procedure of tuning competence. The results obtained indicate that modification of competence of base classifiers during the working phase essentially improves performance of the MCS system and that this improvement depends on the MCS system and tuning method used. Copyright © 2015 Elsevier Ltd. All rights reserved.

Laser scanning measurements on trees for logging harvesting operations.

PubMed

Zheng, Yili; Liu, Jinhao; Wang, Dian; Yang, Ruixi

2012-01-01

Logging harvesters represent a set of high-performance modern forestry machinery, which can finish a series of continuous operations such as felling, delimbing, peeling, bucking and so forth with human intervention. It is found by experiment that during the process of the alignment of the harvesting head to capture the trunk, the operator needs a lot of observation, judgment and repeated operations, which lead to the time and fuel losses. In order to improve the operation efficiency and reduce the operating costs, the point clouds for standing trees are collected with a low-cost 2D laser scanner. A cluster extracting algorithm and filtering algorithm are used to classify each trunk from the point cloud. On the assumption that every cross section of the target trunk is approximate a standard circle and combining the information of an Attitude and Heading Reference System, the radii and center locations of the trunks in the scanning range are calculated by the Fletcher-Reeves conjugate gradient algorithm. The method is validated through experiments in an aspen forest, and the optimized calculation time consumption is compared with the previous work of other researchers. Moreover, the implementation of the calculation result for automotive capturing trunks by the harvesting head during the logging operation is discussed in particular.

Improvement of portable computed tomography system for on-field applications

NASA Astrophysics Data System (ADS)

Sukrod, K.; Khoonkamjorn, P.; Tippayakul, C.

2015-05-01

In 2010, Thailand Institute of Nuclear Technology (TINT) received a portable Computed Tomography (CT) system from the IAEA as part of the Regional Cooperative Agreement (RCA) program. This portable CT system has been used as the prototype for development of portable CT system intended for industrial applications since then. This paper discusses the improvements in the attempt to utilize the CT system for on-field applications. The system is foreseen to visualize the amount of agarwood in the live tree trunk. The experiments adopting Am-241 as the radiation source were conducted. The Am-241 source was selected since it emits low energy gamma which should better distinguish small density differences of wood types. Test specimens made of timbers with different densities were prepared and used in the experiments. The cross sectional views of the test specimens were obtained from the CT system using different scanning parameters. It is found from the experiments that the results are promising as the picture can clearly differentiate wood types according to their densities. Also, the optimum scanning parameters were determined from the experiments. The results from this work encourage the research team to advance into the next phase which is to experiment with the real tree on the field.

Tree species preferences of foraging songbirds during spring migration in floodplain forests of the Upper Mississippi River

USGS Publications Warehouse

Kirsch, Eileen M.; Wellik, Mike J.

2017-01-01

Floodplain forest of the Upper Mississippi River is important for songbirds during spring migration. However, the altered hydrology of this system and spread of reed canary grass (Phalaris arundinacea) and emerald ash borer (Agrilus planipennis) threaten tree diversity and long-term sustainability of this forest. We estimated tree preferences of songbirds during spring migration 2010–2013 to help guide management decisions that promote tree diversity and forest sustainability and to evaluate yearly variation in tree selection. We used the point center-quarter method to assess relative availability of tree species and tallied bird foraging observations on tree species as well as recording the phenophase of used trees on five 40 ha plots of contiguous floodplain forest between La Crosse, Wisconsin and New Albin, Iowa, from 15 April through 1 June. We quantified bird preferences by comparing proportional use of tree species by each bird species to estimates of tree species availability for all 4 y and for each year separately. Species that breed locally preferred silver maple (Acer saccharinum), which is dominant in this forest. The common transient migrant species and the suite of 17 transient wood warbler species preferred hackberry (Celtis occidentalis) and oaks (Quercus spp.), which are limited to higher elevations on the floodplain. We observed earlier leaf development the warm springs of 2010 and 2012 and later leaf development the cold springs of 2011 and 2013. Yellow-rumped Warbler (Setophaga coronata), American Redstart (S. ruticilla), Warbling Vireo (Vireo gilvus) and Baltimore Oriole (Icterus galbula), and the suite of transient migrant wood warblers spread their foraging efforts among tree species in colder springs and were more selective in warmer springs. All three of the important tree species are not regenerating well on the UMR and widespread die-off of silver maple is possible in 50 y without large scale management.

Coalescent methods for estimating phylogenetic trees.

PubMed

Liu, Liang; Yu, Lili; Kubatko, Laura; Pearl, Dennis K; Edwards, Scott V

2009-10-01

We review recent models to estimate phylogenetic trees under the multispecies coalescent. Although the distinction between gene trees and species trees has come to the fore of phylogenetics, only recently have methods been developed that explicitly estimate species trees. Of the several factors that can cause gene tree heterogeneity and discordance with the species tree, deep coalescence due to random genetic drift in branches of the species tree has been modeled most thoroughly. Bayesian approaches to estimating species trees utilizes two likelihood functions, one of which has been widely used in traditional phylogenetics and involves the model of nucleotide substitution, and the second of which is less familiar to phylogeneticists and involves the probability distribution of gene trees given a species tree. Other recent parametric and nonparametric methods for estimating species trees involve parsimony criteria, summary statistics, supertree and consensus methods. Species tree approaches are an appropriate goal for systematics, appear to work well in some cases where concatenation can be misleading, and suggest that sampling many independent loci will be paramount. Such methods can also be challenging to implement because of the complexity of the models and computational time. In addition, further elaboration of the simplest of coalescent models will be required to incorporate commonly known issues such as deviation from the molecular clock, gene flow and other genetic forces.

Microsatellite marker development in Peony using next generation sequencing

Treesearch

Barbara Gilmore; Nahla Bassil; April Nyberg; Brian Knaus; Don Smith; Danny L. Barney; Kim Hummer

2013-01-01

Peonies (Paeonia), the grand garden perennial of spring and early summer, are economically important to the international cut flower market. Herbaceous peonies (Paeonia section Paeonia), tree peonies (Paeonia section Moutan), and intersectional crosses between the two types (...

Applying Data Mining Techniques to Extract Hidden Patterns about Breast Cancer Survival in an Iranian Cohort Study.

PubMed

Khalkhali, Hamid Reza; Lotfnezhad Afshar, Hadi; Esnaashari, Omid; Jabbari, Nasrollah

2016-01-01

Breast cancer survival has been analyzed by many standard data mining algorithms. A group of these algorithms belonged to the decision tree category. Ability of the decision tree algorithms in terms of visualizing and formulating of hidden patterns among study variables were main reasons to apply an algorithm from the decision tree category in the current study that has not studied already. The classification and regression trees (CART) was applied to a breast cancer database contained information on 569 patients in 2007-2010. The measurement of Gini impurity used for categorical target variables was utilized. The classification error that is a function of tree size was measured by 10-fold cross-validation experiments. The performance of created model was evaluated by the criteria as accuracy, sensitivity and specificity. The CART model produced a decision tree with 17 nodes, 9 of which were associated with a set of rules. The rules were meaningful clinically. They showed in the if-then format that Stage was the most important variable for predicting breast cancer survival. The scores of accuracy, sensitivity and specificity were: 80.3%, 93.5% and 53%, respectively. The current study model as the first one created by the CART was able to extract useful hidden rules from a relatively small size dataset.

Computerized Adaptive Test vs. decision trees: Development of a support decision system to identify suicidal behavior.

PubMed

Delgado-Gomez, D; Baca-Garcia, E; Aguado, D; Courtet, P; Lopez-Castroman, J

2016-12-01

Several Computerized Adaptive Tests (CATs) have been proposed to facilitate assessments in mental health. These tests are built in a standard way, disregarding useful and usually available information not included in the assessment scales that could increase the precision and utility of CATs, such as the history of suicide attempts. Using the items of a previously developed scale for suicidal risk, we compared the performance of a standard CAT and a decision tree in a support decision system to identify suicidal behavior. We included the history of past suicide attempts as a class for the separation of patients in the decision tree. The decision tree needed an average of four items to achieve a similar accuracy than a standard CAT with nine items. The accuracy of the decision tree, obtained after 25 cross-validations, was 81.4%. A shortened test adapted for the separation of suicidal and non-suicidal patients was developed. CATs can be very useful tools for the assessment of suicidal risk. However, standard CATs do not use all the information that is available. A decision tree can improve the precision of the assessment since they are constructed using a priori information. Copyright © 2016 Elsevier B.V. All rights reserved.

Nutrients in foliage and wet deposition of nitrate, ammonium and sulfate in washing tree top in Abies religiosa forests

Treesearch

E.R Peña-Mendoza; A. Gómez-Guerrero; Mark Fenn; P. Hernández de la Rosa; D. Alvarado Rosales

2016-01-01

The nutritional content and tree top in the forests are evaluated of Abies religiosa, San Miguel Tlaixpan (SMT) and Rio Frio (RF), State of Mexico. The work had two parts. In the first, the nutritional content was evaluated in new foliage (N, P, K, Ca and Mg) in Abies religiosa trees, in periods of spring, summer and winter, in...

Real-Time Speech/Music Classification With a Hierarchical Oblique Decision Tree

DTIC Science & Technology

2008-04-01

REAL-TIME SPEECH/ MUSIC CLASSIFICATION WITH A HIERARCHICAL OBLIQUE DECISION TREE Jun Wang, Qiong Wu, Haojiang Deng, Qin Yan Institute of Acoustics...time speech/ music classification with a hierarchical oblique decision tree. A set of discrimination features in frequency domain are selected...handle signals without discrimination and can not work properly in the existence of multimedia signals. This paper proposes a real-time speech/ music

Growth of a pole-size ponderosa on cutover land in relation to selection of trees for pruning.

Treesearch

Lloyd G. Gillmore; Forrest W. Jones

1954-01-01

The expected growth of pole-size ponderosa pine on cutover land should be considered in selecting those trees which will grow fast enough in the future to warrant investment in pruning. This consideration is especially important because most pruning work is done within 2 or 3 years after cutting and before the release effect of cutting is evident on reserved trees....

Strategic tree planting as an EPA encouraged pollutant reduction strategy: how urban trees can obtain credit in state implementation plans

Treesearch

Dr. David J. Nowak

2005-01-01

As tree programs are new to the SIP process, "to facilitate Federal approval of an emerging or voluntary measure States are encouraged to work with their EPA regional ofice during the development process". Programs to increase canopy cover in urban areas can achieve many benefits. They can help improve air and water quality, as well as other factors related...

Long term radiocesium contamination of fruit trees following the Chernobyl accident.

PubMed

Antonopoulos-Domis, M; Clouvas, A; Gagianas, A

1996-12-01

Radiocesium contamination from the Chernobyl accident of fruits and leaves from various fruit trees was systematically studied from 1990 to 1995 on two agricultural experimentation farms in Northern Greece. The results are discussed in the framework of a previously published model describing the long-term radiocesium contamination mechanism of deciduous fruit trees after a nuclear accident. The results of the present work qualitatively verify the model predictions.

Some thoughts about tree planting and nursery culture in New Hampshire

Treesearch

Kenneth M. Desmarais

2008-01-01

As a forester one of the best and worse things about my work is the time involved to grow a forest. Most benefits of my work will be realized long after my last steps are taken on this earth. It's comforting to me to know that 3 generations from now, people will be harvesting trees that I have planted, or that have regenerated from cuttings that I have made in the...

Lidar-based individual tree species classification using convolutional neural network

NASA Astrophysics Data System (ADS)

Mizoguchi, Tomohiro; Ishii, Akira; Nakamura, Hiroyuki; Inoue, Tsuyoshi; Takamatsu, Hisashi

2017-06-01

Terrestrial lidar is commonly used for detailed documentation in the field of forest inventory investigation. Recent improvements of point cloud processing techniques enabled efficient and precise computation of an individual tree shape parameters, such as breast-height diameter, height, and volume. However, tree species are manually specified by skilled workers to date. Previous works for automatic tree species classification mainly focused on aerial or satellite images, and few works have been reported for classification techniques using ground-based sensor data. Several candidate sensors can be considered for classification, such as RGB or multi/hyper spectral cameras. Above all candidates, we use terrestrial lidar because it can obtain high resolution point cloud in the dark forest. We selected bark texture for the classification criteria, since they clearly represent unique characteristics of each tree and do not change their appearance under seasonable variation and aged deterioration. In this paper, we propose a new method for automatic individual tree species classification based on terrestrial lidar using Convolutional Neural Network (CNN). The key component is the creation step of a depth image which well describe the characteristics of each species from a point cloud. We focus on Japanese cedar and cypress which cover the large part of domestic forest. Our experimental results demonstrate the effectiveness of our proposed method.

Method for interconverting drying and heating times between round and square cross sections of ponderosa pine

Treesearch

William T. Simpson

2005-01-01

To use small-diameter trees effectively as square timbers, we need to be able to estimate the amount of time it takes for these timbers to air-dry. Since experimental data on estimating air-drying time for small-diameter logs have been developed, this study looked at a way to relate that method to square timbers. Drying times were determined for a group of round cross-...

Estimating phylogenetic trees from genome-scale data.

PubMed

Liu, Liang; Xi, Zhenxiang; Wu, Shaoyuan; Davis, Charles C; Edwards, Scott V

2015-12-01

The heterogeneity of signals in the genomes of diverse organisms poses challenges for traditional phylogenetic analysis. Phylogenetic methods known as "species tree" methods have been proposed to directly address one important source of gene tree heterogeneity, namely the incomplete lineage sorting that occurs when evolving lineages radiate rapidly, resulting in a diversity of gene trees from a single underlying species tree. Here we review theory and empirical examples that help clarify conflicts between species tree and concatenation methods, and misconceptions in the literature about the performance of species tree methods. Considering concatenation as a special case of the multispecies coalescent model helps explain differences in the behavior of the two methods on phylogenomic data sets. Recent work suggests that species tree methods are more robust than concatenation approaches to some of the classic challenges of phylogenetic analysis, including rapidly evolving sites in DNA sequences and long-branch attraction. We show that approaches, such as binning, designed to augment the signal in species tree analyses can distort the distribution of gene trees and are inconsistent. Computationally efficient species tree methods incorporating biological realism are a key to phylogenetic analysis of whole-genome data. © 2015 New York Academy of Sciences.

Quantitative 3D reconstruction of airway and pulmonary vascular trees using HRCT

NASA Astrophysics Data System (ADS)

Wood, Susan A.; Hoford, John D.; Hoffman, Eric A.; Zerhouni, Elias A.; Mitzner, Wayne A.

1993-07-01

Accurate quantitative measurements of airway and vascular dimensions are essential to evaluate function in the normal and diseased lung. In this report, a novel method is described for three-dimensional extraction and analysis of pulmonary tree structures using data from High Resolution Computed Tomography (HRCT). Serially scanned two-dimensional slices of the lower left lobe of isolated dog lungs were stacked to create a volume of data. Airway and vascular trees were three-dimensionally extracted using a three dimensional seeded region growing algorithm based on difference in CT number between wall and lumen. To obtain quantitative data, we reduced each tree to its central axis. From the central axis, branch length is measured as the distance between two successive branch points, branch angle is measured as the angle produced by two daughter branches, and cross sectional area is measured from a plane perpendicular to the central axis point. Data derived from these methods can be used to localize and quantify structural differences both during changing physiologic conditions and in pathologic lungs.

Factor complexity of crash occurrence: An empirical demonstration using boosted regression trees.

PubMed

Chung, Yi-Shih

2013-12-01

Factor complexity is a characteristic of traffic crashes. This paper proposes a novel method, namely boosted regression trees (BRT), to investigate the complex and nonlinear relationships in high-variance traffic crash data. The Taiwanese 2004-2005 single-vehicle motorcycle crash data are used to demonstrate the utility of BRT. Traditional logistic regression and classification and regression tree (CART) models are also used to compare their estimation results and external validities. Both the in-sample cross-validation and out-of-sample validation results show that an increase in tree complexity provides improved, although declining, classification performance, indicating a limited factor complexity of single-vehicle motorcycle crashes. The effects of crucial variables including geographical, time, and sociodemographic factors explain some fatal crashes. Relatively unique fatal crashes are better approximated by interactive terms, especially combinations of behavioral factors. BRT models generally provide improved transferability than conventional logistic regression and CART models. This study also discusses the implications of the results for devising safety policies. Copyright © 2012 Elsevier Ltd. All rights reserved.

Leonardo's branching rule in trees: How self-similar structures resist wind

NASA Astrophysics Data System (ADS)

Eloy, Christophe

2011-11-01

In his notebooks, Leonardo da Vinci observed that ``all the branches of a tree at every stage of its height when put together are equal in thickness to the trunk,'' which means that the total cross-sectional area of branches is conserved across branching nodes. The usual explanation for this rule involves vascular transport of sap, but this argument is questionable because the portion of wood devoted to transport varies across species and can be as low as 5%. It is proposed here that Leonardo's rule is a consequence of the tree skeleton having a self-similar structure and the branch diameters being adjusted to resist wind-induced loads. To address this problem, a continuous model is first considered by neglecting the geometrical details of branching and wind incident angles. The robustness of this analytical model is then assessed with numerical simulations on tree skeletons generated with a simple branching rule producing self-similar structures. This study was supported by the European Union through the fellowship PIOF-GA-2009-252542.

Successful crossings with early flowering transgenic poplar: interspecific crossings, but not transgenesis, promoted aberrant phenotypes in offspring.

PubMed

Hoenicka, Hans; Lehnhardt, Denise; Nilsson, Ove; Hanelt, Dieter; Fladung, Matthias

2014-10-01

In forest tree species, the reproductive phase is reached only after many years or even decades of juvenile growth. Different early flowering systems based on the genetic transfer of heat-shock promoter driven flowering-time genes have been proposed for poplar; however, no fertile flowers were reported until now. Here, we studied flower and pollen development in both HSP::AtFT and wild-type male poplar in detail and developed an optimized heat treatment protocol to obtain fertile HSP::AtFT flowers. Anthers from HSP::AtFT poplar flowers containing fertile pollen grains showed arrested development in stage 12 instead of reaching phase 13 as do wild-type flowers. Pollen grains could be isolated under the binocular microscope and were used for intra- and interspecific crossings with wild-type poplar. F1-seedlings segregating the HSP::AtFT gene construct according to Mendelian laws were obtained. A comparison between intra- and interspecific crossings revealed that genetic transformation had no detrimental effects on F1-seedlings. However, interspecific crossings, a broadly accepted breeding method, produced 47% seedlings with an aberrant phenotype. The early flowering system presented in this study opens new possibilities for accelerating breeding of poplar and other forest tree species. Fast breeding and the selection of transgene-free plants, once the breeding process is concluded, can represent an attractive alternative even under very restrictive regulations. © 2014 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

Gene tree rooting methods give distributions that mimic the coalescent process.

PubMed

Tian, Yuan; Kubatko, Laura S

2014-01-01

Multi-locus phylogenetic inference is commonly carried out via models that incorporate the coalescent process to model the possibility that incomplete lineage sorting leads to incongruence between gene trees and the species tree. An interesting question that arises in this context is whether data "fit" the coalescent model. Previous work (Rosenfeld et al., 2012) has suggested that rooting of gene trees may account for variation in empirical data that has been previously attributed to the coalescent process. We examine this possibility using simulated data. We show that, in the case of four taxa, the distribution of gene trees observed from rooting estimated gene trees with either the molecular clock or with outgroup rooting can be closely matched by the distribution predicted by the coalescent model with specific choices of species tree branch lengths. We apply commonly-used coalescent-based methods of species tree inference to assess their performance in these situations. Copyright © 2013 Elsevier Inc. All rights reserved.

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

PubMed

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

2014-04-01

Studies evaluating plant-soil biota interactions in both native and introduced plant ranges are rare, and thus far have lacked robust experimental designs to account for several potential confounding factors. Here, we investigated the effects of soil biota on growth of Pinus contorta, which has been introduced from Canada to Sweden. Using Swedish and Canadian soils, we conducted two glasshouse experiments. The first experiment utilized unsterilized soil from each country, with a full-factorial cross of soil origin, tree provenance, and fertilizer addition. The second experiment utilized gamma-irradiated sterile soil from each country, with a full-factorial cross of soil origin, soil biota inoculation treatments, tree provenance, and fertilizer addition. The first experiment showed higher seedling growth on Swedish soil relative to Canadian soil. The second experiment showed this effect was due to differences in soil biotic communities between the two countries, and occurred independently of all other experimental factors. Our results provide strong evidence that plant interactions with soil biota can shift from negative to positive following introduction to a new region, and are relevant for understanding the success of some exotic forest plantations, and invasive and range-expanding native species. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

Seasonal variations in the stable oxygen isotope ratio of wood cellulose reveal annual rings of trees in a Central Amazon terra firme forest.

PubMed

Ohashi, Shinta; Durgante, Flávia M; Kagawa, Akira; Kajimoto, Takuya; Trumbore, Susan E; Xu, Xiaomei; Ishizuka, Moriyoshi; Higuchi, Niro

2016-03-01

In Amazonian non-flooded forests with a moderate dry season, many trees do not form anatomically definite annual rings. Alternative indicators of annual rings, such as the oxygen (δ(18)Owc) and carbon stable isotope ratios of wood cellulose (δ(13)Cwc), have been proposed; however, their applicability in Amazonian forests remains unclear. We examined seasonal variations in the δ(18)Owc and δ(13)Cwc of three common species (Eschweilera coriacea, Iryanthera coriacea, and Protium hebetatum) in Manaus, Brazil (Central Amazon). E. coriacea was also sampled in two other regions to determine the synchronicity of the isotopic signals among different regions. The annual cyclicity of δ(18)Owc variation was cross-checked by (14)C dating. The δ(18)Owc showed distinct seasonal variations that matched the amplitude observed in the δ(18)O of precipitation, whereas seasonal δ(13)Cwc variations were less distinct in most cases. The δ(18)Owc variation patterns were similar within and between some individual trees in Manaus. However, the δ(18)Owc patterns of E. coriacea differed by region. The ages of some samples estimated from the δ(18)Owc cycles were offset from the ages estimated by (14)C dating. In the case of E. coriacea, this phenomenon suggested that missing or wedging rings may occur frequently even in well-grown individuals. Successful cross-dating may be facilitated by establishing δ(18)Owc master chronologies at both seasonal and inter-annual scales for tree species with distinct annual rings in each region.

Tree-stem diameter fluctuates with the lunar tides and perhaps with geomagnetic activity.

PubMed

Barlow, Peter W; Mikulecký, Miroslav; Střeštík, Jaroslav

2010-11-01

Our initial objective has been to examine the suggestion of Zürcher et al. (Nature 392:665–666, 1998) that the naturally occurring variations in stem diameter of two experimental trees of Picea alba were related to near simultaneous variations in the lunisolar tidal acceleration. The relationship was positive: Lunar peaks were roughly synchronous with stem diameter peaks. To extend the investigation of this putative relationship, additional data on stem diameter variations from six other tree species were gathered from published literature. Sixteen sets of data were analysed retrospectively using graphical representations as well as cosinor analysis, statistical cross-correlation and cross-spectral analysis, together with estimated values of the lunisolar tidal acceleration corresponding to the sites, dates and times of collection of the biological data. Positive relationships were revealed between the daily variations of stem diameter and the variations of the lunisolar tidal acceleration. Although this relationship could be mediated by a 24.8-h lunar rhythm, the presence of a solar rhythm of 24.0 h could not be ruled out. Studies of transpiration in two of the observed trees indicated that although this variable was not linked to stem diameter variation, it might also be subject to lunisolar gravitational regulation. In three cases, the geomagnetic Thule index showed a weak but reciprocal relationship with stem diameter variation, as well as a positive relationship with the lunisolar tidal force. In conclusion, it seems that lunar gravity alone could influence stem diameter variation and that, under certain circumstances, additional regulation may come from the geomagnetic flux.

Rotorblades for large wind turbines

NASA Astrophysics Data System (ADS)

Wackerle, P. M.; Hahn, M.

1981-09-01

Details of the design work and manufacturing process for a running prototype production of 25 m long composite rotor blades for wind energy generators are presented. The blades are of the 'integrated spar design' type and consist of a glass fiber skin and a PVC core. A computer program (and its action tree) is used for the analysis of the multi-connected hybrid cross-section, in order to achieve optimal design specifications. Four tools are needed for the production of two blade types, including two molds, and milling, cutting and drilling jigs. The manufacturing processes for the molds, jigs and blades are discussed in detail. The final acceptance of the blade is based on a static test where the flexibility of the blade is checked by magnitude of load and deflection, and a dynamic test evaluating the natural frequencies in bending and torsion.

Water Stress Impacts Tree-Atmosphere Interaction in the Amazon

NASA Astrophysics Data System (ADS)

van Emmerik, T. H. M.; Steele-Dunne, S. C.; Gentine, P.; Oliveira, R. S.; Van De Giesen, N.

2017-12-01

Land-atmosphere interactions depend on momentum exchange from the atmosphere to the canopy, which depends on the tree drag coefficient. It is known that the drag coefficient, and thus tree-atmosphere interaction, can vary strongly within a canopy. Yet, only few measurements are available to study the variation of tree-atmosphere interaction in time and space, and in response to vegetation water stress. Recent work [1] demonstrated how accelerometers can be used to study tree properties and responses. For this study, accelerometers were used to derive a measure of tree-atmosphere interaction for 19 individual trees of seven different species in the Brazilian Amazon. This study demonstrates that under field conditions, tree-atmosphere interaction can vary considerably in time and space. The five month measurement period included the transitioning from the wet to the dry season. We demonstrate that increased tree water deficit, measured with dendrometers, is related to observed changes in tree-atmosphere interaction, which is hypothesized to be caused by water stress induced changes in tree mass. References [1]. van Emmerik, T.; Steele-Dunne, S.; Hut, R.; Gentine, P.; Guerin, M.; Oliveira, R.S.; Wagner, J.; Selker, J.; van de Giesen, N. Measuring Tree Properties and Responses Using Low-Cost Accelerometers. Sensors 2017, 17, 1098.

Cross-Layer Protocol Combining Tree Routing and TDMA Slotting in Wireless Sensor Networks

NASA Astrophysics Data System (ADS)

Bai, Ronggang; Ji, Yusheng; Lin, Zhiting; Wang, Qinghua; Zhou, Xiaofang; Qu, Yugui; Zhao, Baohua

Being different from other networks, the load and direction of data traffic for wireless sensor networks are rather predictable. The relationships between nodes are cooperative rather than competitive. These features allow the design approach of a protocol stack to be able to use the cross-layer interactive way instead of a hierarchical structure. The proposed cross-layer protocol CLWSN optimizes the channel allocation in the MAC layer using the information from the routing tables, reduces the conflicting set, and improves the throughput. Simulations revealed that it outperforms SMAC and MINA in terms of delay and energy consumption.

Microsatellite marker development in peony using next generation sequencing

USDA-ARS?s Scientific Manuscript database

Peonies (Paeonia), the grand garden perennial of spring and early summer, are economically important to the international cut flower market. Herbaceous peonies (Paeonia section Paeonia), tree peonies (Paeonia section Moutan), and intersectional crosses between the two types (Itoh Paeonia hybrids) ...

Urban forest management in New England: Towards a contemporary understanding of tree wardens in Massachusetts communities

USGS Publications Warehouse

Harper, Richard W.; Bloniarz, David V.; DeStefano, Stephen; Nicolson, Craig

2017-01-01

In the New England states, tree wardens are local officials responsible for the preservation, maintenance and stewardship of municipal public trees. This study explores the emerging professional challenges, duties and responsibilities of tree wardens, from the subject’s point of view, by conducting in-person, semi-structured qualitative research interviews with 50 tree wardens throughout Massachusetts. Many of the findings corroborate previous literature, including that tree wardens are typically housed in a municipal department (often public works or highway), that tree wardens routinely interact with a wide variety of local organisations (representatives from other municipal departments, community volunteer associations) and that as community size increases, tree wardens typically have access to a greater pool of resources to carry out urban forest management. A newer finding is that the subject of urban forest health arose as a topic of great importance for tree wardens, as nearly all interviewees (n = 49) indicated that they monitor for urban forest pests and that they would like further continuing education concerning this subject.

The value of countryside elements in the conservation of a threatened arboreal marsupial Petaurus norfolcensis in agricultural landscapes of south-eastern Australia--the disproportional value of scattered trees.

PubMed

Crane, Mason J; Lindenmayer, David B; Cunningham, Ross B

2014-01-01

Human activities, particularly agriculture, have transformed much of the world's terrestrial environment. Within these anthropogenic landscapes, a variety of relictual and semi-natural habitats exist, which we term countryside elements. The habitat value of countryside elements (hereafter termed 'elements') is increasingly recognised. We quantify the relative value of four kinds of such 'elements' (linear roadside remnants, native vegetation patches, scattered trees and tree plantings) used by a threatened Australian arboreal marsupial, the squirrel glider (Petaurus norfolcensis). We examined relationships between home range size and the availability of each 'element' and whether the usage was relative to predicted levels of use. The use of 'elements' by gliders was largely explained by their availability, but there was a preference for native vegetation patches and scattered trees. We found home range size was significantly smaller with increasing area of scattered trees and a contrasting effect with increasing area of linear roadside remnants or native vegetation patches. Our work showed that each 'element' was used and as such had a role in the conservation of the squirrel glider, but their relative value varied. We illustrate the need to assess the conservation value of countryside elements so they can be incorporated into the holistic management of agricultural landscapes. This work demonstrates the disproportional value of scattered trees, underscoring the need to specifically incorporate and/or enhance the protection and recruitment of scattered trees in biodiversity conservation policy and management.

Evaluating the responses of forest ecosystems to climate change and CO2 using dynamic global vegetation models.

PubMed

Song, Xiang; Zeng, Xiaodong

2017-02-01

The climate has important influences on the distribution and structure of forest ecosystems, which may lead to vital feedback to climate change. However, much of the existing work focuses on the changes in carbon fluxes or water cycles due to climate change and/or atmospheric CO 2 , and few studies have considered how and to what extent climate change and CO 2 influence the ecosystem structure (e.g., fractional coverage change) and the changes in the responses of ecosystems with different characteristics. In this work, two dynamic global vegetation models (DGVMs): IAP-DGVM coupled with CLM3 and CLM4-CNDV, were used to investigate the response of the forest ecosystem structure to changes in climate (temperature and precipitation) and CO 2 concentration. In the temperature sensitivity tests, warming reduced the global area-averaged ecosystem gross primary production in the two models, which decreased global forest area. Furthermore, the changes in tree fractional coverage (Δ F tree ; %) from the two models were sensitive to the regional temperature and ecosystem structure, i.e., the mean annual temperature (MAT; °C) largely determined whether Δ F tree was positive or negative, while the tree fractional coverage ( F tree ; %) played a decisive role in the amplitude of Δ F tree around the globe, and the dependence was more remarkable in IAP-DGVM. In cases with precipitation change, F tree had a uniformly positive relationship with precipitation, especially in the transition zones of forests (30% <  F tree  < 60%) for IAP-DGVM and in semiarid and arid regions for CLM4-CNDV. Moreover, Δ F tree had a stronger dependence on F tree than on the mean annual precipitation (MAP; mm/year). It was also demonstrated that both models captured the fertilization effects of the CO 2 concentration.

Innovations in Site Characterization Case Study: Site Cleanup of the Wenatchee Tree Fruit Test Plot Site Using a Dynamic Work Plan

EPA Pesticide Factsheets

The Wenatchee Tree Fruit Research and Extension Center site contained soils contaminated with organochlorine pesticides, organophosphorus pesticides, and other pesticides due to agriculture-related research activities conducted from 1966 until...

Monitoring small pioneer trees in the forest-tundra ecotone: using multi-temporal airborne laser scanning data to model height growth.

PubMed

Hauglin, Marius; Bollandsås, Ole Martin; Gobakken, Terje; Næsset, Erik

2017-12-08

Monitoring of forest resources through national forest inventory programmes is carried out in many countries. The expected climate changes will affect trees and forests and might cause an expansion of trees into presently treeless areas, such as above the current alpine tree line. It is therefore a need to develop methods that enable the inclusion of also these areas into monitoring programmes. Airborne laser scanning (ALS) is an established tool in operational forest inventories, and could be a viable option for monitoring tasks. In the present study, we used multi-temporal ALS data with point density of 8-15 points per m 2 , together with field measurements from single trees in the forest-tundra ecotone along a 1500-km-long transect in Norway. The material comprised 262 small trees with an average height of 1.78 m. The field-measured height growth was derived from height measurements at two points in time. The elapsed time between the two measurements was 4 years. Regression models were then used to model the relationship between ALS-derived variables and tree heights as well as the height growth. Strong relationships between ALS-derived variables and tree heights were found, with R 2 values of 0.93 and 0.97 for the two points in time. The relationship between the ALS data and the field-derived height growth was weaker, with R 2 values of 0.36-0.42. A cross-validation gave corresponding results, with root mean square errors of 19 and 11% for the ALS height models and 60% for the model relating ALS data to single-tree height growth.

Tree Nuts Are Inversely Associated with Metabolic Syndrome and Obesity: The Adventist Health Study-2

PubMed Central

Jaceldo-Siegl, Karen; Haddad, Ella; Oda, Keiji; Fraser, Gary E.; Sabaté, Joan

2014-01-01

Objective To examine the relationships of nut consumption, metabolic syndrome (MetS), and obesity in the Adventist Health Study-2, a relatively healthy population with a wide range of nut intake. Research Design and Methods Cross-sectional analysis was conducted on clinical, dietary, anthropometric, and demographic data of 803 adults. MetS was defined according to the American Heart Association and the National Heart, Lung, and Blood Institute diagnostic criteria. We assessed intake of total nuts, tree nuts and peanuts, and also classified subjects into low tree nut/low peanut (LT/LP), low tree/high peanut (LT/HP), high tree nut/high peanut (HT/HP), and high tree/low peanut (HT/LP) consumers. Odds ratios were estimated using multivariable logistic regression. Results 32% of subjects had MetS. Compared to LT/LP consumers, obesity was lower in LT/HP (OR = 0.89; 95% CI = 0.53, 1.48), HT/HP (OR = 0.63; 95% CI = 0.40, 0.99) and HT/LP (OR = 0.54; 95% CI = 0.34, 0.88) consumers, p for trend = 0.006. For MetS, odds ratios (95% CI) were 0.77 (0.47, 1.28), 0.65 (0.42, 1.00) and 0.68 (0.43, 1.07), respectively (p for trend = 0.056). Frequency of nut intake (once/week) had significant inverse associations with MetS (3% less for tree nuts and 2% less for total nuts) and obesity (7% less for tree nuts and 3% less for total nuts). Conclusions Tree nuts appear to have strong inverse association with obesity, and favorable though weaker association with MetS independent of demographic, lifestyle and dietary factors. PMID:24416351

Tree nuts are inversely associated with metabolic syndrome and obesity: the Adventist health study-2.

PubMed

Jaceldo-Siegl, Karen; Haddad, Ella; Oda, Keiji; Fraser, Gary E; Sabaté, Joan

2014-01-01

To examine the relationships of nut consumption, metabolic syndrome (MetS), and obesity in the Adventist Health Study-2, a relatively healthy population with a wide range of nut intake. Cross-sectional analysis was conducted on clinical, dietary, anthropometric, and demographic data of 803 adults. MetS was defined according to the American Heart Association and the National Heart, Lung, and Blood Institute diagnostic criteria. We assessed intake of total nuts, tree nuts and peanuts, and also classified subjects into low tree nut/low peanut (LT/LP), low tree/high peanut (LT/HP), high tree nut/high peanut (HT/HP), and high tree/low peanut (HT/LP) consumers. Odds ratios were estimated using multivariable logistic regression. 32% of subjects had MetS. Compared to LT/LP consumers, obesity was lower in LT/HP (OR = 0.89; 95% CI = 0.53, 1.48), HT/HP (OR = 0.63; 95% CI = 0.40, 0.99) and HT/LP (OR = 0.54; 95% CI = 0.34, 0.88) consumers, p for trend = 0.006. For MetS, odds ratios (95% CI) were 0.77 (0.47, 1.28), 0.65 (0.42, 1.00) and 0.68 (0.43, 1.07), respectively (p for trend = 0.056). Frequency of nut intake (once/week) had significant inverse associations with MetS (3% less for tree nuts and 2% less for total nuts) and obesity (7% less for tree nuts and 3% less for total nuts). Tree nuts appear to have strong inverse association with obesity, and favorable though weaker association with MetS independent of demographic, lifestyle and dietary factors.

[Difference in responses of major tree species growth to climate in the Miyaluo Mountains, western Sichuan, China].

PubMed

Guo, Ming-ming; Zhang, Yuan-dong; Wang, Xiao-chun; Liu, Shi-rong

2015-08-01

To explore the responses of different tree species growth to climate change in the semi-humid region of the eastern Tibetan Plateau, we investigated climate-growth relationships of Tsuga chinensis, Abies faxoniana, Picea purpurea at an altitude of 3000 m (low altitude) and A. faxoniana and Larix mastersiana at an altitude of 4000 m (high altitude) using tree ring-width chronologies (total of 182 cores) developed from Miyaluo, western Sichuan, China. Five residual chronologies were developed from the cross-dated ring width series using the program ARSTAN, and the relationships between monthly climate variables and tree-ring index were analyzed. Results showed that the chronologies of trees at low altitudes were negatively correlated with air temperature but positively with precipitation in April and May. This indicated that drought stress limited tree growth at low altitude, but different tree species showed significant variations. T. chinensis was most severely affected by drought stress, followed by A. faxoniana and P. purpurea. Trees at high altitude were mainly affected by growing season temperature. Tree-ring index of A. faxoniana was positively correlated with monthly minimum temperature in February and July of the current year and monthly maximum temperature in October of the previous year. Radial growth of L. mastersiana was positively correlated with monthly maximum temperature in May, and negatively with monthly mean temperature in February and monthly minimum temperature in March. In recent decadal years, the climate in northeast Tibetan Plateau had a warming and drying trend. If this trend continues, we could deduce that P. purpurea should grow faster than T. chinensis and A. faxoniana at low altitudes, while A. faxoniana would benefit more from global warming at high altitudes.

Common tree shrews and primates share leukocyte membrane antigens.

PubMed

Palley, L S; Schlossman, S F; Letvin, N L

1984-01-01

Monoclonal antibodies reactive with human peripheral blood lymphocyte and myeloid cell surface antigens were utilized to study the phylogeny of the common tree shrew. Blood cells from the common tree shrew, but not the bat or short-tailed shrew, react with certain of these antibodies. These data strengthen the argument that the Tupaiidae are primitive primates rather than insectivores. They also indicate that this approach should be useful for further work in taxonomic systemization.

The Design and the Implementation of the Machinery for Whitewashing the Trunks

NASA Astrophysics Data System (ADS)

Chen, Xuehui; Yuan, Genfu; Huang, Lei; Wang, Riguang; Lei, Jingfa; Chen, Congsheng

Whitewashing the trunks is an important part in the management of tree greening in winter, which can prevent the pests and the livestock grazing the trunks, strengthen the winter-proofing ability of trees and enhance the esthetic effect of amenity. In this paper, an innovative mechanical design idea that the trees are brushed by the lime water with the insect repellant has been introduced. Meanwhile, the numerical simulation technology has been also employed to analyze the important components of this machine, which can improve the reliability and the economy of the design. The practice shows that this product can significantly improve the work efficiency and reduce the labor intensity through comparing with the traditional working ways.

Measuring Timber Truck Loads With Image Processing In Paper Mills

NASA Astrophysics Data System (ADS)

Silva, M. Santos; Carvalho, Fernando D.; Rodrigues, F. Carvalho; Goncalves, Ana N. R.

1989-04-01

The raw material for the paper industry is wood. To have an exact account of the stock of piled sawn tree trunks every truck load entering the plant's stockyard must be measured as to the amount of wood being brought in. Weighting down the trucks has its own problems, mainly, due to the high capacity of the tree trunks to absorb water. This problem is further enhanced when calculations must be made to arrive at the mass of sawn tree trunks which must go into the process of producing a certain quantity of paper pulp. The method presented here is based on two fixed cameras which take the image of the truck load. One takes a view of the trunks in order to get information on the average length of the tree trunks. The other obtains a side view which is digitised and by just discriminating against a grey level the area covered by the tree trunk cross section is measured. A simple arithmetic operation gives the volume of wood in the trunk. The same computer, a PC, will register the trucks particulars is almost independent of weather the wood is wet or dry and it serves trucks of any size.

Meta-analysis reveals that hydraulic traits explain cross-species patterns of drought-induced tree mortality across the globe.

PubMed

Anderegg, William R L; Klein, Tamir; Bartlett, Megan; Sack, Lawren; Pellegrini, Adam F A; Choat, Brendan; Jansen, Steven

2016-05-03

Drought-induced tree mortality has been observed globally and is expected to increase under climate change scenarios, with large potential consequences for the terrestrial carbon sink. Predicting mortality across species is crucial for assessing the effects of climate extremes on forest community biodiversity, composition, and carbon sequestration. However, the physiological traits associated with elevated risk of mortality in diverse ecosystems remain unknown, although these traits could greatly improve understanding and prediction of tree mortality in forests. We performed a meta-analysis on species' mortality rates across 475 species from 33 studies around the globe to assess which traits determine a species' mortality risk. We found that species-specific mortality anomalies from community mortality rate in a given drought were associated with plant hydraulic traits. Across all species, mortality was best predicted by a low hydraulic safety margin-the difference between typical minimum xylem water potential and that causing xylem dysfunction-and xylem vulnerability to embolism. Angiosperms and gymnosperms experienced roughly equal mortality risks. Our results provide broad support for the hypothesis that hydraulic traits capture key mechanisms determining tree death and highlight that physiological traits can improve vegetation model prediction of tree mortality during climate extremes.

Application of Ground-Penetrating Radar for Detecting Internal Anomalies in Tree Trunks with Irregular Contours.

PubMed

Li, Weilin; Wen, Jian; Xiao, Zhongliang; Xu, Shengxia

2018-02-22

To assess the health conditions of tree trunks, it is necessary to estimate the layers and anomalies of their internal structure. The main objective of this paper is to investigate the internal part of tree trunks considering their irregular contour. In this respect, we used ground penetrating radar (GPR) for non-invasive detection of defects and deteriorations in living trees trunks. The Hilbert transform algorithm and the reflection amplitudes were used to estimate the relative dielectric constant. The point cloud data technique was applied as well to extract the irregular contours of trunks. The feasibility and accuracy of the methods were examined through numerical simulations, laboratory and field measurements. The results demonstrated that the applied methodology allowed for accurate characterizations of the internal inhomogeneity. Furthermore, the point cloud technique resolved the trunk well by providing high-precision coordinate information. This study also demonstrated that cross-section tomography provided images with high resolution and accuracy. These integrated techniques thus proved to be promising for observing tree trunks and other cylindrical objects. The applied approaches offer a great promise for future 3D reconstruction of tomographic images with radar wave.

Classification of Parkinsonian syndromes from FDG-PET brain data using decision trees with SSM/PCA features.

PubMed

Mudali, D; Teune, L K; Renken, R J; Leenders, K L; Roerdink, J B T M

2015-01-01

Medical imaging techniques like fluorodeoxyglucose positron emission tomography (FDG-PET) have been used to aid in the differential diagnosis of neurodegenerative brain diseases. In this study, the objective is to classify FDG-PET brain scans of subjects with Parkinsonian syndromes (Parkinson's disease, multiple system atrophy, and progressive supranuclear palsy) compared to healthy controls. The scaled subprofile model/principal component analysis (SSM/PCA) method was applied to FDG-PET brain image data to obtain covariance patterns and corresponding subject scores. The latter were used as features for supervised classification by the C4.5 decision tree method. Leave-one-out cross validation was applied to determine classifier performance. We carried out a comparison with other types of classifiers. The big advantage of decision tree classification is that the results are easy to understand by humans. A visual representation of decision trees strongly supports the interpretation process, which is very important in the context of medical diagnosis. Further improvements are suggested based on enlarging the number of the training data, enhancing the decision tree method by bagging, and adding additional features based on (f)MRI data.

Multivariate analysis of flow cytometric data using decision trees.

PubMed

Simon, Svenja; Guthke, Reinhard; Kamradt, Thomas; Frey, Oliver

2012-01-01

Characterization of the response of the host immune system is important in understanding the bidirectional interactions between the host and microbial pathogens. For research on the host site, flow cytometry has become one of the major tools in immunology. Advances in technology and reagents allow now the simultaneous assessment of multiple markers on a single cell level generating multidimensional data sets that require multivariate statistical analysis. We explored the explanatory power of the supervised machine learning method called "induction of decision trees" in flow cytometric data. In order to examine whether the production of a certain cytokine is depended on other cytokines, datasets from intracellular staining for six cytokines with complex patterns of co-expression were analyzed by induction of decision trees. After weighting the data according to their class probabilities, we created a total of 13,392 different decision trees for each given cytokine with different parameter settings. For a more realistic estimation of the decision trees' quality, we used stratified fivefold cross validation and chose the "best" tree according to a combination of different quality criteria. While some of the decision trees reflected previously known co-expression patterns, we found that the expression of some cytokines was not only dependent on the co-expression of others per se, but was also dependent on the intensity of expression. Thus, for the first time we successfully used induction of decision trees for the analysis of high dimensional flow cytometric data and demonstrated the feasibility of this method to reveal structural patterns in such data sets.

An efficient and extensible approach for compressing phylogenetic trees

PubMed Central

2011-01-01

Background Biologists require new algorithms to efficiently compress and store their large collections of phylogenetic trees. Our previous work showed that TreeZip is a promising approach for compressing phylogenetic trees. In this paper, we extend our TreeZip algorithm by handling trees with weighted branches. Furthermore, by using the compressed TreeZip file as input, we have designed an extensible decompressor that can extract subcollections of trees, compute majority and strict consensus trees, and merge tree collections using set operations such as union, intersection, and set difference. Results On unweighted phylogenetic trees, TreeZip is able to compress Newick files in excess of 98%. On weighted phylogenetic trees, TreeZip is able to compress a Newick file by at least 73%. TreeZip can be combined with 7zip with little overhead, allowing space savings in excess of 99% (unweighted) and 92%(weighted). Unlike TreeZip, 7zip is not immune to branch rotations, and performs worse as the level of variability in the Newick string representation increases. Finally, since the TreeZip compressed text (TRZ) file contains all the semantic information in a collection of trees, we can easily filter and decompress a subset of trees of interest (such as the set of unique trees), or build the resulting consensus tree in a matter of seconds. We also show the ease of which set operations can be performed on TRZ files, at speeds quicker than those performed on Newick or 7zip compressed Newick files, and without loss of space savings. Conclusions TreeZip is an efficient approach for compressing large collections of phylogenetic trees. The semantic and compact nature of the TRZ file allow it to be operated upon directly and quickly, without a need to decompress the original Newick file. We believe that TreeZip will be vital for compressing and archiving trees in the biological community. PMID:22165819

An efficient and extensible approach for compressing phylogenetic trees.

PubMed

Matthews, Suzanne J; Williams, Tiffani L

2011-10-18

Biologists require new algorithms to efficiently compress and store their large collections of phylogenetic trees. Our previous work showed that TreeZip is a promising approach for compressing phylogenetic trees. In this paper, we extend our TreeZip algorithm by handling trees with weighted branches. Furthermore, by using the compressed TreeZip file as input, we have designed an extensible decompressor that can extract subcollections of trees, compute majority and strict consensus trees, and merge tree collections using set operations such as union, intersection, and set difference. On unweighted phylogenetic trees, TreeZip is able to compress Newick files in excess of 98%. On weighted phylogenetic trees, TreeZip is able to compress a Newick file by at least 73%. TreeZip can be combined with 7zip with little overhead, allowing space savings in excess of 99% (unweighted) and 92%(weighted). Unlike TreeZip, 7zip is not immune to branch rotations, and performs worse as the level of variability in the Newick string representation increases. Finally, since the TreeZip compressed text (TRZ) file contains all the semantic information in a collection of trees, we can easily filter and decompress a subset of trees of interest (such as the set of unique trees), or build the resulting consensus tree in a matter of seconds. We also show the ease of which set operations can be performed on TRZ files, at speeds quicker than those performed on Newick or 7zip compressed Newick files, and without loss of space savings. TreeZip is an efficient approach for compressing large collections of phylogenetic trees. The semantic and compact nature of the TRZ file allow it to be operated upon directly and quickly, without a need to decompress the original Newick file. We believe that TreeZip will be vital for compressing and archiving trees in the biological community.

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

PubMed

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.

Electrical treeing behaviors in silicone rubber under an impulse voltage considering high temperature

NASA Astrophysics Data System (ADS)

Yunxiao, ZHANG; Yuanxiang, ZHOU; Ling, ZHANG; Zhen, LIN; Jie, LIU; Zhongliu, ZHOU

2018-05-01

In this paper, work was conducted to reveal electrical tree behaviors (initiation and propagation) of silicone rubber (SIR) under an impulse voltage with high temperature. Impulse frequencies ranging from 10 Hz to 1 kHz were applied and the temperature was controlled between 30 °C and 90 °C. Experimental results show that tree initiation voltage decreases with increasing pulse frequency, and the descending amplitude is different in different frequency bands. As the pulse frequency increases, more frequent partial discharges occur in the channel, increasing the tree growth rate and the final shape intensity. As for temperature, the initiation voltage decreases and the tree shape becomes denser as the temperature gets higher. Based on differential scanning calorimetry results, we believe that partial segment relaxation of SIR at high temperature leads to a decrease in the initiation voltage. However, the tree growth rate decreases with increasing temperature. Carbonization deposition in the channel under high temperature was observed under microscope and proven by Raman analysis. Different tree growth models considering tree channel characteristics are proposed. It is believed that increasing the conductivity in the tree channel restrains the partial discharge, holding back the tree growth at high temperature.

Binary partition tree analysis based on region evolution and its application to tree simplification.

PubMed

Lu, Huihai; Woods, John C; Ghanbari, Mohammed

2007-04-01

Pyramid image representations via tree structures are recognized methods for region-based image analysis. Binary partition trees can be applied which document the merging process with small details found at the bottom levels and larger ones close to the root. Hindsight of the merging process is stored within the tree structure and provides the change histories of an image property from the leaf to the root node. In this work, the change histories are modelled by evolvement functions and their second order statistics are analyzed by using a knee function. Knee values show the reluctancy of each merge. We have systematically formulated these findings to provide a novel framework for binary partition tree analysis, where tree simplification is demonstrated. Based on an evolvement function, for each upward path in a tree, the tree node associated with the first reluctant merge is considered as a pruning candidate. The result is a simplified version providing a reduced solution space and still complying with the definition of a binary tree. The experiments show that image details are preserved whilst the number of nodes is dramatically reduced. An image filtering tool also results which preserves object boundaries and has applications for segmentation.

Eighteen microsatellite loci in Salix arbutifolia (Salicaceae) and cross-species amplification in Salix and Populus species.

PubMed

Hoshikawa, Takeshi; Kikuchi, Satoshi; Nagamitsu, Teruyoshi; Tomaru, Nobuhiro

2009-07-01

Salix arbutifolia is a riparian dioecious tree species that is of conservation concern in Japan because of its highly restricted distribution. Eighteen polymorphic loci of dinucleotide microsatellites were isolated and characterized. Among these, estimates of the expected heterozygosity ranged from 0.350 to 0.879. Cross-species amplification was successful at 9-13 loci among six Salix species and at three loci in one Populus species. © 2009 Blackwell Publishing Ltd.

Knot probabilities in random diagrams

NASA Astrophysics Data System (ADS)

Cantarella, Jason; Chapman, Harrison; Mastin, Matt

2016-10-01

We consider a natural model of random knotting—choose a knot diagram at random from the finite set of diagrams with n crossings. We tabulate diagrams with 10 and fewer crossings and classify the diagrams by knot type, allowing us to compute exact probabilities for knots in this model. As expected, most diagrams with 10 and fewer crossings are unknots (about 78% of the roughly 1.6 billion 10 crossing diagrams). For these crossing numbers, the unknot fraction is mostly explained by the prevalence of ‘tree-like’ diagrams which are unknots for any assignment of over/under information at crossings. The data shows a roughly linear relationship between the log of knot type probability and the log of the frequency rank of the knot type, analogous to Zipf’s law for word frequency. The complete tabulation and all knot frequencies are included as supplementary data.

Design of physical and logical topologies with fault-tolerant ability in wavelength-routed optical network

NASA Astrophysics Data System (ADS)

Chen, Chunfeng; Liu, Hua; Fan, Ge

2005-02-01

In this paper we consider the problem of designing a network of optical cross-connects(OXCs) to provide end-to-end lightpath services to label switched routers (LSRs). Like some previous work, we select the number of OXCs as our objective. Compared with the previous studies, we take into account the fault-tolerant characteristic of logical topology. First of all, using a Prufer number randomly generated, we generate a tree. By adding some edges to the tree, we can obtain a physical topology which consists of a certain number of OXCs and fiber links connecting OXCs. It is notable that we for the first time limit the number of layers of the tree produced according to the method mentioned above. Then we design the logical topologies based on the physical topologies mentioned above. In principle, we will select the shortest path in addition to some consideration on the load balancing of links and the limitation owing to the SRLG. Notably, we implement the routing algorithm for the nodes in increasing order of the degree of the nodes. With regarding to the problem of the wavelength assignment, we adopt the heuristic algorithm of the graph coloring commonly used. It is clear our problem is computationally intractable especially when the scale of the network is large. We adopt the taboo search algorithm to find the near optimal solution to our objective. We present numerical results for up to 1000 LSRs and for a wide range of system parameters such as the number of wavelengths supported by each fiber link and traffic. The results indicate that it is possible to build large-scale optical networks with rich connectivity in a cost-effective manner, using relatively few but properly dimensioned OXCs.

Assembly and Analysis of Differential Transcriptome Responses of Hevea brasiliensis on Interaction with Microcyclus ulei

PubMed Central

Restrepo Restrepo, Silvia; Aristizábal Gutiérrez, Fabio Ancizar; Montoya Castaño, Dolly

2015-01-01

Natural rubber (Hevea brasiliensis) is a tropical tree used commercially for the production of latex, from which 40,000 products are generated. The fungus Microcyclus ulei infects this tree, causing South American leaf blight (SALB) disease. This disease causes developmental delays and significant crop losses, thereby decreasing the production of latex. Currently several groups are working on obtaining clones of rubber tree with durable resistance to SALB through the use of extensive molecular biology techniques. In this study, we used a secondary clone that was resistant to M. ulei isolate GCL012. This clone, FX 3864 was obtained by crossing between clones PB 86 and B 38 (H. brasiliensis x H. brasiliensis). RNA-Seq high-throughput sequencing technology was used to analyze the differential expression of the FX 3864 clone transcriptome at 0 and 48 h post infection (hpi) with the M. ulei isolate GCL012. A total of 158,134,220 reads were assembled using the de novo assembly strategy to generate 90,775 contigs with an N50 of 1672. Using a reference-based assembly, 76,278 contigs were generated with an N50 of 1324. We identified 86 differentially expressed genes associated with the defense response of FX 3864 to GCL012. Seven putative genes members of the AP2/ERF ethylene (ET)-dependent superfamily were found to be down-regulated. An increase in salicylic acid (SA) was associated with the up-regulation of three genes involved in cell wall synthesis and remodeling, as well as in the down-regulation of the putative gene CPR5. The defense response of FX 3864 against the GCL012 isolate was associated with the antagonistic SA, ET and jasmonic acid (JA) pathways. These responses are characteristic of plant resistance to biotrophic pathogens. PMID:26287380

Landscape-scale changes in forest canopy structure across a partially logged tropical peat swamp

NASA Astrophysics Data System (ADS)

Wedeux, B. M. M.; Coomes, D. A.

2015-07-01

Forest canopy structure is strongly influenced by environmental factors and disturbance, and in turn influences key ecosystem processes including productivity, evapotranspiration and habitat availability. In tropical forests increasingly modified by human activities, the interplaying effects of environmental factors and disturbance legacies on forest canopy structure across landscapes are practically unexplored. We used high-fidelity airborne laser scanning (ALS) data to measure the canopy of old-growth and selectively logged peat swamp forest across a peat dome in Central Kalimantan, Indonesia, and quantified how canopy structure metrics varied with peat depth and under logging. Several million canopy gaps in different height cross-sections of the canopy were measured in 100 plots of 1 km2 spanning the peat dome, allowing us to describe canopy structure with seven metrics. Old-growth forest became shorter and had simpler vertical canopy profiles on deeper peat, consistently with previous work linking deep peat to stunted tree growth. Gap Size Frequency Distributions (GSFDs) indicated fewer and smaller canopy gaps on the deeper peat (i.e. the scaling exponent of pareto functions increased from 1.76 to 3.76 with peat depth). Areas subjected to concessionary logging until 2000, and informal logging since then, had the same canopy top height as old-growth forest, indicating the persistence of some large trees, but mean canopy height was significantly reduced; the total area of canopy gaps increased and the GSFD scaling exponent was reduced. Logging effects were most evident on the deepest peat, where nutrient depletion and waterlogged conditions restrain tree growth and recovery. A tight relationship exists between canopy structure and the peat deph gradient within the old-growth tropical peat swamp. This relationship breaks down after selective logging, with canopy structural recovery being modulated by environmental conditions.

Pollen dispersal of tropical trees (Dinizia excelsa: Fabaceae) by native insects and African honeybees in pristine and fragmented Amazonian rainforest.

PubMed

Dick, Christopher W; Etchelecu, Gabriela; Austerlitz, Frédéric

2003-03-01

Tropical rainforest trees typically occur in low population densities and rely on animals for cross-pollination. It is of conservation interest therefore to understand how rainforest fragmentation may alter the pollination and breeding structure of remnant trees. Previous studies of the Amazonian tree Dinizia excelsa (Fabaceae) found African honeybees (Apis mellifera scutellata) as the predominant pollinators of trees in highly disturbed habitats, transporting pollen up to 3.2 km between pasture trees. Here, using microsatellite genotypes of seed arrays, we compare outcrossing rates and pollen dispersal distances of (i) remnant D. excelsa in three large ranches, and (ii) a population in undisturbed forest in which African honeybees were absent. Self-fertilization was more frequent in the disturbed habitats (14%, n = 277 seeds from 12 mothers) than in undisturbed forest (10%, n = 295 seeds from 13 mothers). Pollen dispersal was extensive in all three ranches compared to undisturbed forest, however. Using a twogener analysis, we estimated a mean pollen dispersal distance of 1509 m in Colosso ranch, assuming an exponential dispersal function, and 212 m in undisturbed forest. The low effective density of D. excelsa in undisturbed forest (approximately 0.1 trees/ha) indicates that large areas of rainforest must be preserved to maintain minimum viable populations. Our results also suggest, however, that in highly disturbed habitats Apis mellifera may expand genetic neighbourhood areas, thereby linking fragmented and continuous forest populations.

Plasticity in Vegetative Growth over Contrasted Growing Sites of an F1 Olive Tree Progeny during Its Juvenile Phase.

PubMed

Ben Sadok, Inès; Martinez, Sebastien; Moutier, Nathalie; Garcia, Gilbert; Leon, Lorenzo; Belaj, Angelina; De La Rosa, Raúl; Khadari, Bouchaib; Costes, Evelyne

2015-01-01

Climatic changes impact fruit tree growth and severely limit their production. Investigating the tree ability to cope with environmental variations is thus necessary to adapt breeding and management strategies in order to ensure sustainable production. In this study, we assessed the genetic parameters and genotype by environment interaction (GxE) during the early tree growth. One hundred and twenty olive seedlings derived from the cross 'Olivière' x 'Arbequina' were examined across two sites with contrasted environments, accounting for ontogenetic trends over three years. Models including the year of growth, branching order, environment, genotype effects, and their interactions were built with variance function and covariance structure of residuals when necessary. After selection of a model, broad sense heritabilities were estimated. Despite strong environmental effect on most traits, no GxE was found. Moreover, the internal structure of traits co-variation was similar in both sites. Ontogenetic growth variation, related to (i) the overall tree form and (ii) the growth and branching habit at growth unit scale, was not altered by the environment. Finally, a moderate to strong genetic control was identified for traits at the whole tree scale and at internode scale. Among all studied traits, the maximal internode length exhibited the highest heritability (H2 = 0.74). Considering the determinant role of this trait in tree architecture and its stability across environments, this study consolidates its relevance for breeding.

Plasticity in Vegetative Growth over Contrasted Growing Sites of an F1 Olive Tree Progeny during Its Juvenile Phase

PubMed Central

Ben Sadok, Inès; Martinez, Sebastien; Moutier, Nathalie; Garcia, Gilbert; Leon, Lorenzo; Belaj, Angelina; De La Rosa, Raúl; Khadari, Bouchaib; Costes, Evelyne

2015-01-01

Climatic changes impact fruit tree growth and severely limit their production. Investigating the tree ability to cope with environmental variations is thus necessary to adapt breeding and management strategies in order to ensure sustainable production. In this study, we assessed the genetic parameters and genotype by environment interaction (GxE) during the early tree growth. One hundred and twenty olive seedlings derived from the cross ‘Olivière’ x ‘Arbequina’ were examined across two sites with contrasted environments, accounting for ontogenetic trends over three years. Models including the year of growth, branching order, environment, genotype effects, and their interactions were built with variance function and covariance structure of residuals when necessary. After selection of a model, broad sense heritabilities were estimated. Despite strong environmental effect on most traits, no GxE was found. Moreover, the internal structure of traits co-variation was similar in both sites. Ontogenetic growth variation, related to (i) the overall tree form and (ii) the growth and branching habit at growth unit scale, was not altered by the environment. Finally, a moderate to strong genetic control was identified for traits at the whole tree scale and at internode scale. Among all studied traits, the maximal internode length exhibited the highest heritability (H2 = 0.74). Considering the determinant role of this trait in tree architecture and its stability across environments, this study consolidates its relevance for breeding. PMID:26062090

Parallel peak pruning for scalable SMP contour tree computation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carr, Hamish A.; Weber, Gunther H.; Sewell, Christopher M.

As data sets grow to exascale, automated data analysis and visualisation are increasingly important, to intermediate human understanding and to reduce demands on disk storage via in situ analysis. Trends in architecture of high performance computing systems necessitate analysis algorithms to make effective use of combinations of massively multicore and distributed systems. One of the principal analytic tools is the contour tree, which analyses relationships between contours to identify features of more than local importance. Unfortunately, the predominant algorithms for computing the contour tree are explicitly serial, and founded on serial metaphors, which has limited the scalability of this formmore » of analysis. While there is some work on distributed contour tree computation, and separately on hybrid GPU-CPU computation, there is no efficient algorithm with strong formal guarantees on performance allied with fast practical performance. Here in this paper, we report the first shared SMP algorithm for fully parallel contour tree computation, withfor-mal guarantees of O(lgnlgt) parallel steps and O(n lgn) work, and implementations with up to 10x parallel speed up in OpenMP and up to 50x speed up in NVIDIA Thrust.« less

Elastic modulus of tree frog adhesive toe pads.

PubMed

Barnes, W Jon P; Goodwyn, Pablo J Perez; Nokhbatolfoghahai, Mohsen; Gorb, Stanislav N

2011-10-01

Previous work using an atomic force microscope in nanoindenter mode indicated that the outer, 10- to 15-μm thick, keratinised layer of tree frog toe pads has a modulus of elasticity equivalent to silicone rubber (5-15 MPa) (Scholz et al. 2009), but gave no information on the physical properties of deeper structures. In this study, micro-indentation is used to measure the stiffness of whole toe pads of the tree frog, Litoria caerulea. We show here that tree frog toe pads are amongst the softest of biological structures (effective elastic modulus 4-25 kPa), and that they exhibit a gradient of stiffness, being stiffest on the outside. This stiffness gradient results from the presence of a dense network of capillaries lying beneath the pad epidermis, which probably has a shock absorbing function. Additionally, we compare the physical properties (elastic modulus, work of adhesion, pull-off force) of the toe pads of immature and adult frogs.

HT/HP x-tree and downhole fiber optic connectors and their use on subsea intelligent wells

NASA Astrophysics Data System (ADS)

Wright, Perry; Barlow, Stewart

2004-12-01

Offshore Oil and Gas R&D has been committed to improved reservoir performance through production monitoring. Technology improvements in these areas offer the greatest potential returns through increased knowledge of the reservoir, and the improvements in real-time production control that the technology and knowledge base can provide. One area of technology that supports this development is the growing application of fiber optic sensors for reservoir and production monitoring. These sensors cannot function in isolation, and need support in the form of fiber optic connection systems for x-tree penetrations. ODI have been developing products for fiber optic tree penetrations and down-hole wet connections for the last 4 years, working with Intelligent Wells Group at BP America Production Company in Houston. This paper discusses the application and reliability of fiber optic connectors, and reviews the development of the ODI I-CONN connection system and its application for vertical and horizontal x-trees, work-over systems and running tools, and down-hole systems.

Individual tree detection in intact forest and degraded forest areas in the north region of Mato Grosso State, Brazilian Amazon

NASA Astrophysics Data System (ADS)

Santos, E. G.; Jorge, A.; Shimabukuro, Y. E.; Gasparini, K.

2017-12-01

The State of Mato Grosso - MT has the second largest area with degraded forest among the states of the Brazilian Legal Amazon. Land use and land cover change processes that occur in this region cause the loss of forest biomass, releasing greenhouse gases that contribute to the increase of temperature on earth. These degraded forest areas lose biomass according to the intensity and magnitude of the degradation type. The estimate of forest biomass, commonly performed by forest inventory through sample plots, shows high variance in degraded forest areas. Due to this variance and complexity of tropical forests, the aim of this work was to estimate forest biomass using LiDAR point clouds in three distinct forest areas: one degraded by fire, another by selective logging and one area of intact forest. The approach applied in these areas was the Individual Tree Detection (ITD). To isolate the trees, we generated Canopy Height Models (CHM) images, which are obtained by subtracting the Digital Elevation Model (MDE) and the Digital Terrain Model (MDT), created by the cloud of LiDAR points. The trees in the CHM images are isolated by an algorithm provided by the Quantitative Ecology research group at the School of Forestry at Northern Arizona University (SILVA, 2015). With these points, metrics were calculated for some areas, which were used in the model of biomass estimation. The methodology used in this work was expected to reduce the error in biomass estimate in the study area. The cloud points of the most representative trees were analyzed, and thus field data was correlated with the individual trees found by the proposed algorithm. In a pilot study, the proposed methodology was applied generating the individual tree metrics: total height and area of the crown. When correlating 339 isolated trees, an unsatisfactory R² was obtained, as heights found by the algorithm were lower than those obtained in the field, with an average difference of 2.43 m. This shows that the algorithm used to isolate trees in temperate areas did not obtained satisfactory results in the tropical forest of Mato Grosso State. Due to this, in future works two algorithms, one developed by Dalponte et al. (2015) and another by Li et al. (2012) will be used.

The Hybrid White Spruce X Himalayan Spruce

Treesearch

H. Nienstaedt; D. P. Fowler

1982-01-01

Picea glauca and P. amithiana were successfully crossed. Crossability ranged from 2 to 30 percent depending on the female P. glauca parent tree. Early characteristics and growth in Wisconsin and in New Brunswick are described. P. smithiana relatedness in the genus is discussed

Biotechnology of trees: Chestnut

Treesearch

C.D. Nelson; W.A. Powell; S.A. Merkle; J.E. Carlson; F.V. Hebard; N Islam-Faridi; M.E. Staton; L. Georgi

2014-01-01

Biotechnology has been practiced on chestnuts (Castanea spp.) for many decades, including vegetative propagation, controlled crossing followed by testing and selection, genetic and cytogenetic mapping, genetic modifi cation, and gene and genome sequencing. Vegetative propagation methods have ranged from grafting and rooting to somatic embryogenesis, often in...

Development of microsatellite markers for Anadenanthera colubrina (Leguminosae), a neotropical tree species.

PubMed

Feres, Juliana Massimino; Monteiro, Mariza; Zucchi, Maria I; Pinheiro, José B; Mestriner, Moacyr A; Alzate-Marin, Ana Lilia

2012-04-01

We developed and characterized nuclear microsatellite markers for Anadenanthera colubrina, a tropical tree species widely distributed in South America. Leaf samples of mature A. colubrina trees, popularly called "angico," were collected from an area that is greatly impacted by agricultural practices in the region of Ribeirão Preto in São Paulo State in southeastern Brazil. Twenty simple sequence repeat (SSR) markers were developed, 14 of which had polymorphic loci. A total of 96 alleles were detected with an average of 6.86 alleles per polymorphic locus. The expected heterozygosity, calculated at polymorphic loci, ranged from 0.18 to 0.83. Finally, we demonstrated that 18 loci were cross-amplified in A. peregrina. A total of 14 polymorphic markers suggest a high potential for genetic diversity, gene flow, and mating system analyses in A. colubrina.

Developing techniques for cause-responsibility analysis of occupational accidents.

PubMed

Jabbari, Mousa; Ghorbani, Roghayeh

2016-11-01

The aim of this study was to specify the causes of occupational accidents, determine social responsibility and the role of groups involved in work-related accidents. This study develops occupational accidents causes tree, occupational accidents responsibility tree, and occupational accidents component-responsibility analysis worksheet; based on these methods, it develops cause-responsibility analysis (CRA) techniques, and for testing them, analyzes 100 fatal/disabling occupational accidents in the construction setting that were randomly selected from all the work-related accidents in Tehran, Iran, over a 5-year period (2010-2014). The main result of this study involves two techniques for CRA: occupational accidents tree analysis (OATA) and occupational accidents components analysis (OACA), used in parallel for determination of responsible groups and responsibilities rate. From the results, we find that the management group of construction projects has 74.65% responsibility of work-related accidents. The developed techniques are purposeful for occupational accidents investigation/analysis, especially for the determination of detailed list of tasks, responsibilities, and their rates. Therefore, it is useful for preventing work-related accidents by focusing on the responsible group's duties. Copyright © 2016 Elsevier Ltd. All rights reserved.

Dependency of branch diameter growth in young Acer trees on light availability and shoot elongation.

PubMed

Sone, Kosei; Noguchi, Ko; Terashima, Ichiro

2005-01-01

Many biomechanical and theoretical studies have been based on the pipe-model theory, according to which a tree is regarded as an assemblage of pipes, each having the same amount of leaf area or leaf mass. However, the physiological mechanisms underlying the theory have not been extensively examined, particularly at the branch level. We analyzed how branches and trunks thickened in nine young Acer mono Maxim. var. marmoratum (Nichols) Hara f. dissectum (Wesmael) Rehder. and A. rufinerve (Siebold & Zucc.) trees. In particular, we examined the roles of light, allocation of photosynthates and shoot heterogeneity. The cross-sectional area (A) of a branch was proportional to cumulative leaf mass or leaf area of the branch, and cumulative cross-sectional area of the daughter branches (SigmaA) above a branching point was equal to the A of the mother branch. These results indicate the validity of the pipe-model theory. However, the theory was invalid for current-year growth of branch cross-sectional area (DeltaA). The DeltaA/SigmaDeltaA for a branching point was greatest (nearly equal to 1) at the crown surface, decreased with crown depth, and tended to increase again at the trunk base, and DeltaA strongly depended on light interception and the yearly increment of leaves on the branch. We examined factors that influenced DeltaA with multiple regression analysis. The ratio of DeltaA of a branch to branch leaf area depended on both relative irradiance and mean current-year shoot length of the branch, suggesting that diameter growth of a branch is determined by the balance between supply of photosynthates, which depends on light interception by the branch, and demand for photosynthates, which is created by the high cambial activity associated with vigorous shoot elongation.

Using electrical resistivity tomography to differentiate sapwood from heartwood: application to conifers.

PubMed

Guyot, Adrien; Ostergaard, Kasper T; Lenkopane, Mothei; Fan, Junliang; Lockington, David A

2013-02-01

Estimating sapwood area is one of the main sources of error when upscaling point scale sap flow measurements to whole-tree water use. In this study, the potential use of electrical resistivity tomography (ERT) to determine the sapwood-heartwood (SW-HW) boundary is investigated for Pinus elliottii Engelm var. elliottii × Pinus caribaea Morelet var. hondurensis growing in a subtropical climate. Specifically, this study investigates: (i) how electrical resistivity is correlated to either wood moisture content, or electrolyte concentration, or both, and (ii) how the SW-HW boundary is defined in terms of electrical resistivity. Tree cross-sections at breast height are analysed using ERT before being felled and the cross-section surface sampled for analysis of major electrolyte concentrations, wood moisture content and density. Electrical resistivity tomography results show patterns with high resistivities occurring in the inner part of the cross-section, with much lower values towards the outside. The high-resistivity areas were generally smaller than the low-resistivity areas. A comparison between ERT and actual SW area measured after felling shows a slope of the linear regression close to unity (=0.96) with a large spread of values (R(2) = 0.56) mostly due to uncertainties in ERT. Electrolyte concentrations along sampled radial transects (cardinal directions) generally showed no trend from the centre of the tree to the bark. Wood moisture content and density show comparable trends that could explain the resistivity patterns. While this study indicates the potential for application of ERT for estimating SW area, it shows that there remains a need for refinement in locating the SW-HW boundary (e.g., by improvement of the inversion method, or perhaps electrode density) in order to increase the robustness of the method.

Near Road Tree Cover in the Portland, ME EnviroAtlas Community Area

EPA Science Inventory

Internationally, local air pollution from busy roadways is a significant issue for public health. Recent studies have shown that having tree cover between highly-traveled roads and people living, working, and going to school nearby can help to mitigate pollution and potentially r...

The Case of the Similar Trees.

ERIC Educational Resources Information Center

Meyer, Rochelle Wilson

1982-01-01

A possible logical flaw based on similar triangles is discussed with the Sherlock Holmes mystery, "The Muskgrave Ritual." The possible flaw has to do with the need for two trees to have equal growth rates over a 250-year period in order for the solution presented to work. (MP)

Using a Standing-Tree Acoustic Tool to Identify Forest Stands for the Production of Mechanically-Graded Lumber

PubMed Central

Paradis, Normand; Auty, David; Carter, Peter; Achim, Alexis

2013-01-01

This study investigates how the use of a Hitman ST300 acoustic sensor can help identify the best forest stands to be used as supply sources for the production of Machine Stress-Rated (MSR) lumber. Using two piezoelectric sensors, the ST300 measures the velocity of a mechanical wave induced in a standing tree. Measurements were made on 333 black spruce (Picea mariana (Mill.) BSP) trees from the North Shore region, Quebec (Canada) selected across a range of locations and along a chronosequence of elapsed time since the last fire (TSF). Logs were cut from a subsample of 39 trees, and sawn into 77 pieces of 38 mm × 89 mm cross-section before undergoing mechanical testing according to ASTM standard D-4761. A linear regression model was developed to predict the static modulus of elasticity of lumber using tree acoustic velocity and stem diameter at 1.3 m above ground level (R2 = 0.41). Results suggest that, at a regional level, 92% of the black spruce trees meet the requirements of MSR grade 1650Fb-1.5E, whilst 64% and 34% meet the 2100Fb-1.8E and 2400Fb-2.0E, respectively. Mature stands with a TSF < 150 years had 11 and 18% more boards in the latter two categories, respectively, and therefore represented the best supply source for MSR lumber. PMID:23482089

Using a standing-tree acoustic tool to identify forest stands for the production of mechanically-graded lumber.

PubMed

Paradis, Normand; Auty, David; Carter, Peter; Achim, Alexis

2013-03-12

This study investigates how the use of a Hitman ST300 acoustic sensor can help identify the best forest stands to be used as supply sources for the production of Machine Stress-Rated (MSR) lumber. Using two piezoelectric sensors, the ST300 measures the velocity of a mechanical wave induced in a standing tree. Measurements were made on 333 black spruce (Picea mariana (Mill.) BSP) trees from the North Shore region, Quebec (Canada) selected across a range of locations and along a chronosequence of elapsed time since the last fire (TSF). Logs were cut from a subsample of 39 trees, and sawn into 77 pieces of 38 mm × 89 mm cross-section before undergoing mechanical testing according to ASTM standard D-4761. A linear regression model was developed to predict the static modulus of elasticity of lumber using tree acoustic velocity and stem diameter at 1.3 m above ground level (R2 = 0.41). Results suggest that, at a regional level, 92% of the black spruce trees meet the requirements of MSR grade 1650Fb-1.5E, whilst 64% and 34% meet the 2100Fb-1.8E and 2400Fb-2.0E, respectively. Mature stands with a TSF < 150 years had 11 and 18% more boards in the latter two categories, respectively, and therefore represented the best supply source for MSR lumber.

[Rapid prediction of annual ring density of Paulownia elongate standing tress using near infrared spectroscopy].

PubMed

Jiang, Ze-Hui; Wang, Yu-Rong; Fei, Ben-Hua; Fu, Feng; Hse, Chung-Yun

2007-06-01

Rapid prediction of annual ring density of Paulownia elongate standing trees using near infrared spectroscopy was studied. It was non-destructive to collect the samples for trees, that is, the wood cores 5 mm in diameter were unthreaded at the breast height of standing trees instead of fallen trees. Then the spectra data were collected by autoscan method of NIR. The annual ring density was determined by mercury immersion. And the models were made and analyzed by the partial least square (PLS) and full cross validation in the 350-2 500 nm wavelength range. The results showed that high coefficients were obtained between the annual ring and the NIR fitted data. The correlation coefficient of prediction model was 0.88 and 0.91 in the middle diameter and bigger diameter, respectively. Moreover, high coefficients of correlation were also obtained between annual ring density laboratory-determined and the NIR fitted data in the middle diameter of Paulownia elongate standing trees, the correlation coefficient of calibration model and prediction model were 0.90 and 0.83, and the standard errors of calibration (SEC) and standard errors of prediction(SEP) were 0.012 and 0.016, respectively. The method can simply, rapidly and non-destructively estimate the annual ring density of the Paulownia elongate standing trees close to the cutting age.

The hydraulic limitation hypothesis revisited.

PubMed

Ryan, Michael G; Phillips, Nathan; Bond, Barbara J

2006-03-01

We proposed the hydraulic limitation hypothesis (HLH) as a mechanism to explain universal patterns in tree height, and tree and stand biomass growth: height growth slows down as trees grow taller, maximum height is lower for trees of the same species on resource-poor sites and annual wood production declines after canopy closure for even-aged forests. Our review of 51 studies that measured one or more of the components necessary for testing the hypothesis showed that taller trees differ physiologically from shorter, younger trees. Stomatal conductance to water vapour (g(s)), photosynthesis (A) and leaf-specific hydraulic conductance (K L) are often, but not always, lower in taller trees. Additionally, leaf mass per area is often greater in taller trees, and leaf area:sapwood area ratio changes with tree height. We conclude that hydraulic limitation of gas exchange with increasing tree size is common, but not universal. Where hydraulic limitations to A do occur, no evidence supports the original expectation that hydraulic limitation of carbon assimilation is sufficient to explain observed declines in wood production. Any limit to height or height growth does not appear to be related to the so-called age-related decline in wood production of forests after canopy closure. Future work on this problem should explicitly link leaf or canopy gas exchange with tree and stand growth, and consider a more fundamental assumption: whether tree biomass growth is limited by carbon availability.

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

USGS Publications Warehouse

Bernhardt, C.

2011-01-01

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

Looking for trees in the forest: summary tree from posterior samples

PubMed Central

2013-01-01

Background Bayesian phylogenetic analysis generates a set of trees which are often condensed into a single tree representing the whole set. Many methods exist for selecting a representative topology for a set of unrooted trees, few exist for assigning branch lengths to a fixed topology, and even fewer for simultaneously setting the topology and branch lengths. However, there is very little research into locating a good representative for a set of rooted time trees like the ones obtained from a BEAST analysis. Results We empirically compare new and known methods for generating a summary tree. Some new methods are motivated by mathematical constructions such as tree metrics, while the rest employ tree concepts which work well in practice. These use more of the posterior than existing methods, which discard information not directly mapped to the chosen topology. Using results from a large number of simulations we assess the quality of a summary tree, measuring (a) how well it explains the sequence data under the model and (b) how close it is to the “truth”, i.e to the tree used to generate the sequences. Conclusions Our simulations indicate that no single method is “best”. Methods producing good divergence time estimates have poor branch lengths and lower model fit, and vice versa. Using the results presented here, a user can choose the appropriate method based on the purpose of the summary tree. PMID:24093883

Looking for trees in the forest: summary tree from posterior samples.

PubMed

Heled, Joseph; Bouckaert, Remco R

2013-10-04

Bayesian phylogenetic analysis generates a set of trees which are often condensed into a single tree representing the whole set. Many methods exist for selecting a representative topology for a set of unrooted trees, few exist for assigning branch lengths to a fixed topology, and even fewer for simultaneously setting the topology and branch lengths. However, there is very little research into locating a good representative for a set of rooted time trees like the ones obtained from a BEAST analysis. We empirically compare new and known methods for generating a summary tree. Some new methods are motivated by mathematical constructions such as tree metrics, while the rest employ tree concepts which work well in practice. These use more of the posterior than existing methods, which discard information not directly mapped to the chosen topology. Using results from a large number of simulations we assess the quality of a summary tree, measuring (a) how well it explains the sequence data under the model and (b) how close it is to the "truth", i.e to the tree used to generate the sequences. Our simulations indicate that no single method is "best". Methods producing good divergence time estimates have poor branch lengths and lower model fit, and vice versa. Using the results presented here, a user can choose the appropriate method based on the purpose of the summary tree.

Observation of eight ancient olive trees (Olea europaea L.) growing in the Garden of Gethsemane.

PubMed

Petruccelli, Raffaella; Giordano, Cristiana; Salvatici, Maria Cristina; Capozzoli, Laura; Ciaccheri, Leonardo; Pazzini, Massimo; Lain, Orietta; Testolin, Raffaele; Cimato, Antonio

2014-05-01

For thousands of years, olive trees (Olea europaea L.) have been a significant presence and a symbol in the Garden of Gethsemane, a place located at the foot of the Mount of Olives, Jerusalem, remembered for the agony of Jesus Christ before his arrest. This investigation comprises the first morphological and genetic characterization of eight olive trees in the Garden of Gethsemane. Pomological traits, morphometric, and ultrastructural observations as well as SSR (Simple Sequence Repeat) analysis were performed to identify the olive trees. Statistical analyses were conducted to evaluate their morphological variability. The study revealed a low morphological variability and minimal dissimilarity among the olive trees. According to molecular analysis, these trees showed the same allelic profile at all microsatellite loci analyzed. Combining the results of the different analyses carried out in the frame of the present work, we could conclude that the eight olive trees of the Gethsemane Garden have been propagated from a single genotype. Copyright © 2014. Published by Elsevier SAS.

Walking tree heuristics for biological string alignment, gene location, and phylogenies

NASA Astrophysics Data System (ADS)

Cull, P.; Holloway, J. L.; Cavener, J. D.

1999-03-01

Basic biological information is stored in strings of nucleic acids (DNA, RNA) or amino acids (proteins). Teasing out the meaning of these strings is a central problem of modern biology. Matching and aligning strings brings out their shared characteristics. Although string matching is well-understood in the edit-distance model, biological strings with transpositions and inversions violate this model's assumptions. We propose a family of heuristics called walking trees to align biologically reasonable strings. Both edit-distance and walking tree methods can locate specific genes within a large string when the genes' sequences are given. When we attempt to match whole strings, the walking tree matches most genes, while the edit-distance method fails. We also give examples in which the walking tree matches substrings even if they have been moved or inverted. The edit-distance method was not designed to handle these problems. We include an example in which the walking tree "discovered" a gene. Calculating scores for whole genome matches gives a method for approximating evolutionary distance. We show two evolutionary trees for the picornaviruses which were computed by the walking tree heuristic. Both of these trees show great similarity to previously constructed trees. The point of this demonstration is that WHOLE genomes can be matched and distances calculated. The first tree was created on a Sequent parallel computer and demonstrates that the walking tree heuristic can be efficiently parallelized. The second tree was created using a network of work stations and demonstrates that there is suffient parallelism in the phylogenetic tree calculation that the sequential walking tree can be used effectively on a network.

Monte Carlo Simulation of Markov, Semi-Markov, and Generalized Semi- Markov Processes in Probabilistic Risk Assessment

NASA Technical Reports Server (NTRS)

English, Thomas

2005-01-01

A standard tool of reliability analysis used at NASA-JSC is the event tree. An event tree is simply a probability tree, with the probabilities determining the next step through the tree specified at each node. The nodal probabilities are determined by a reliability study of the physical system at work for a particular node. The reliability study performed at a node is typically referred to as a fault tree analysis, with the potential of a fault tree existing.for each node on the event tree. When examining an event tree it is obvious why the event tree/fault tree approach has been adopted. Typical event trees are quite complex in nature, and the event tree/fault tree approach provides a systematic and organized approach to reliability analysis. The purpose of this study was two fold. Firstly, we wanted to explore the possibility that a semi-Markov process can create dependencies between sojourn times (the times it takes to transition from one state to the next) that can decrease the uncertainty when estimating time to failures. Using a generalized semi-Markov model, we studied a four element reliability model and were able to demonstrate such sojourn time dependencies. Secondly, we wanted to study the use of semi-Markov processes to introduce a time variable into the event tree diagrams that are commonly developed in PRA (Probabilistic Risk Assessment) analyses. Event tree end states which change with time are more representative of failure scenarios than are the usual static probability-derived end states.

Water uptake of trees in a montane forest catchment and the geomorphological potential of root growth in Boulder Creek Critical Zone Observatory, Rocky Mountains, Colorado

NASA Astrophysics Data System (ADS)

Skeets, B.; Barnard, H. R.; Byers, A.

2011-12-01

The influence of vegetation on the hydrological cycle and the possible effect of roots in geomorphological processes are poorly understood. Gordon Gulch watershed in the Front Range of the Rocky Mountains, Colorado, is a montane climate ecosystem of the Boulder Creek Critical Zone Observatory whose study adds to the database of ecohydrological work in different climates. This work sought to identify the sources of water used by different tree species and to determine how trees growing in rock outcrops may contribute to the fracturing and weathering of rock. Stable isotopes (18O and 2H) were analyzed from water extracted from soil and xylem samples. Pinus ponderosa on the south-facing slope consumes water from deeper depths during dry periods and uses newly rain-saturated soils, after rainfall events. Pinus contorta on the north -facing slope shows a similar, expected response in water consumption, before and after rain. Two trees (Pinus ponderosa) growing within rock outcrops demonstrate water use from cracks replenished by new rains. An underexplored question in geomorphology is whether tree roots growing in rock outcrops contribute to long-term geomorphological processes by physically deteriorating the bedrock. The dominant roots of measured trees contributed approximately 30 - 80% of total water use, seen especially after rainfall events. Preliminary analysis of root growth rings indicates that root growth is capable of expanding rock outcrop fractures at an approximate rate of 0.6 - 1.0 mm per year. These results demonstrate the significant role roots play in tree physiological processes and in bedrock deterioration.

Preservation of hippocampal neuron numbers and hippocampal subfield volumes in behaviorally characterized aged tree shrews.

PubMed

Keuker, Jeanine I H; de Biurrun, Gabriel; Luiten, Paul G M; Fuchs, Eberhard

2004-01-19

Aging is associated with a decreased ability to store and retrieve information. The hippocampal formation plays a critical role in such memory processes, and its integrity is affected during normal aging. We used tree shrews (Tupaia belangeri) as an animal model of aging, because in many characteristics, tree shrews are closer to primates than they are to rodents. Young and aged male tree shrews performed a holeboard spatial memory task, which permits assessment of reference and working memory. Upon completion of the behavioral measurements, we carried out modified stereological analyses of neuronal numbers in various subdivisions of the hippocampus and used the Cavalieri method to calculate the volumes of these subfields. Results showed that the working memory of aged tree shrews was significantly impaired compared with that of young animals, whereas the hippocampus-dependent reference memory remained unchanged by aging. Estimation of the number of neurons revealed preserved neuron numbers in the subiculum, in the subregions CA1, CA2, CA3, and in the hilus of the dentate gyrus. Volume measurements showed no aging-related changes in the volume of any of these hippocampal subregions, or in the molecular and granule cell layers of the dentate gyrus of tree shrews. We conclude that the observed changes in memory performance in aging tree shrews are not accompanied by observable reductions of hippocampal neuron numbers or hippocampal volume, rather, the changes in memory performance are more likely the result of modified subcellular mechanisms that are affected by the aging process. Copyright 2003 Wiley-Liss, Inc.

The Value of Countryside Elements in the Conservation of a Threatened Arboreal Marsupial Petaurus norfolcensis in Agricultural Landscapes of South-Eastern Australia—The Disproportional Value of Scattered Trees

PubMed Central

Crane, Mason J.; Lindenmayer, David B.; Cunningham, Ross B.

2014-01-01

Human activities, particularly agriculture, have transformed much of the world's terrestrial environment. Within these anthropogenic landscapes, a variety of relictual and semi-natural habitats exist, which we term countryside elements. The habitat value of countryside elements (hereafter termed ‘elements’) is increasingly recognised. We quantify the relative value of four kinds of such ‘elements’ (linear roadside remnants, native vegetation patches, scattered trees and tree plantings) used by a threatened Australian arboreal marsupial, the squirrel glider (Petaurus norfolcensis). We examined relationships between home range size and the availability of each ‘element’ and whether the usage was relative to predicted levels of use. The use of ‘elements’ by gliders was largely explained by their availability, but there was a preference for native vegetation patches and scattered trees. We found home range size was significantly smaller with increasing area of scattered trees and a contrasting effect with increasing area of linear roadside remnants or native vegetation patches. Our work showed that each ‘element’ was used and as such had a role in the conservation of the squirrel glider, but their relative value varied. We illustrate the need to assess the conservation value of countryside elements so they can be incorporated into the holistic management of agricultural landscapes. This work demonstrates the disproportional value of scattered trees, underscoring the need to specifically incorporate and/or enhance the protection and recruitment of scattered trees in biodiversity conservation policy and management. PMID:25216045

A divide and conquer approach to cope with uncertainty, human health risk, and decision making in contaminant hydrology

NASA Astrophysics Data System (ADS)

de Barros, Felipe P. J.; Bolster, Diogo; Sanchez-Vila, Xavier; Nowak, Wolfgang

2011-05-01

Assessing health risk in hydrological systems is an interdisciplinary field. It relies on the expertise in the fields of hydrology and public health and needs powerful translation concepts to provide decision support and policy making. Reliable health risk estimates need to account for the uncertainties and variabilities present in hydrological, physiological, and human behavioral parameters. Despite significant theoretical advancements in stochastic hydrology, there is still a dire need to further propagate these concepts to practical problems and to society in general. Following a recent line of work, we use fault trees to address the task of probabilistic risk analysis and to support related decision and management problems. Fault trees allow us to decompose the assessment of health risk into individual manageable modules, thus tackling a complex system by a structural divide and conquer approach. The complexity within each module can be chosen individually according to data availability, parsimony, relative importance, and stage of analysis. Three differences are highlighted in this paper when compared to previous works: (1) The fault tree proposed here accounts for the uncertainty in both hydrological and health components, (2) system failure within the fault tree is defined in terms of risk being above a threshold value, whereas previous studies that used fault trees used auxiliary events such as exceedance of critical concentration levels, and (3) we introduce a new form of stochastic fault tree that allows us to weaken the assumption of independent subsystems that is required by a classical fault tree approach. We illustrate our concept in a simple groundwater-related setting.

A cross-cultural investigation of college student alcohol consumption: a classification tree analysis.

PubMed

Kitsantas, Panagiota; Kitsantas, Anastasia; Anagnostopoulou, Tanya

2008-01-01

In this cross-cultural study, the authors attempted to identify high-risk subgroups for alcohol consumption among college students. American and Greek students (N = 132) answered questions about alcohol consumption, religious beliefs, attitudes toward drinking, advertisement influences, parental monitoring, and drinking consequences. Heavy drinkers in the American group were younger and less religious than were infrequent drinkers. In the Greek group, heavy drinkers tended to deny the negative results of drinking alcohol and use a permissive attitude to justify it, whereas infrequent drinkers were more likely to be monitored by their parents. These results suggest that parental monitoring and an emphasis on informing students about the negative effects of alcohol on their health and social and academic lives may be effective methods of reducing alcohol consumption. Classification tree analysis revealed that student attitudes toward drinking were important in the classification of American and Greek drinkers, indicating that this is a powerful predictor of alcohol consumption regardless of ethnic background.

Relationships of tree height and diameter at breast height revisited: analyses of stem growth using 20-year data of an even-aged Chamaecyparis obtusa stand

PubMed Central

Sumida, Akihiro; Miyaura, Tomiyasu; Torii, Hitoshi

2013-01-01

Stem diameter at breast height (DBH) and tree height (H) are commonly used measures of tree growth. We examined patterns of height growth and diameter growth along a stem using a 20-year record of an even-aged hinoki cypress (Chamaecyparis obtusa (Siebold & Zucc.) Endl.) stand. In the region of the stem below the crown (except for the butt swell), diameter growth rates (ΔD) at different heights tended to increase slightly from breast height upwards. This increasing trend was pronounced in suppressed trees, but not as much as the variation in ΔD among individual trees. Hence, ΔD below the crown can be regarded as generally being represented by the DBH growth rate (ΔDBH) of a tree. Accordingly, the growth rate of the stem cross-sectional area increased along the stem upwards in suppressed trees, but decreased in dominant trees. The stem diameter just below the crown base (DCB), the square of which is an index of the amount of leaves on a tree, was an important factor affecting ΔDBH. DCB also had a strong positive relationship with crown length. Hence, long-term changes in the DCB of a tree were associated with long-term changes in crown length, determined by the balance between the height growth rate (ΔH) and the rising rate of the crown base (ΔHCB). Within the crown, ΔD's were generally greater than the rates below the crown. Even dying trees (ΔD ≈ 0 below the crown) maintained ΔD > 0 within the crown and ΔH > 0 until about 5 years before death. This growth within the crown may be related to the need to produce new leaves to compensate for leaves lost owing to the longevity of the lower crown. These results explain the different time trajectories in DBH–H relationships among individual trees, and also the long-term changes in the DBH–H relationships. The view that a rise in the crown base is strongly related to leaf turnover helps to interpret DBH–H relationships. PMID:23303367

Downstream impacts of a Central Amazonian hydroelectric dam on tree growth and mortality in floodplain forests

NASA Astrophysics Data System (ADS)

Resende, A. F. D.; Silva, T. S. F.; Silva, J. D. S.; Piedade, M. T. F.; Streher, A. S.; Ferreira-Ferreira, J.; Schongart, J.

2017-12-01

The flood pulse of large Amazonian Rivers is characterized by predictable high- and low-water periods during the annual cycle, and is the main driving force in the floodplains regulating decomposition, nutrient cycles, productivity, life cycles and growth rhythms of floodplains' biota. Over at least 20 millions of years, tree species in these ecosystems developed complex adaptative mechanisms to tolerate flooding, such as the tree species Macrolobium acaciifolium (Fabaceae) and Eschweilera tenuifolia (Lecythidaceae) occupying the lower topographic positions in the floodplain forests along the oligothrophic black-water rivers. Tree growth occurs mainly during terrestrial phase, while during the aquatic phase the anoxic conditions result into a cambial dormancy and formation of annual tree rings. The hydroelectric dam Balbina which was installed in the Uatumã River (central Amazonia) during the 1980s altered significantly the flood pulse regime resulting into higher minimum and lower maximum annual water levels. The suppression of the terrestrial phase caused large-scale mortality of flood-adapted trees growing on the lower topographic positions, as evidenced by radiocarbon dating and cross-dating techniques (dendrochronology). In this study we estimated the extension of dead forests using high resolution ALOS/PALSAR radar images, for their detection along a fluvial distance of more than 280 km downstream of the power plant. Further we analyzed tree growth of 60 living individuals of E. tenuifolia by tree-ring analyses comparing the post- and pre-dam periods. We evaluated the impacts of the altered hydrological regime on tree growth considering ontogenetic effects and the fluvial distance of the trees to the dam. Since the Balbina power plant started operating the associated igapó forests lost about 11% of its cover. We found a significant reduction of tree growth of E. tenuifolia during the post-dam period as a consequence of the increasing aquatic phase duration. This impact was stronger for younger trees (<200 yr) and for those growing closer to the hydroelectric dam (<100 km distance). Considering the planning of construction of several dozen dams in the Amazon there is an urgent need to consider these downstream impacts in all discussions of hydroelectric power plants implementation and operation.

Autumn Algorithm-Computation of Hybridization Networks for Realistic Phylogenetic Trees.

PubMed

Huson, Daniel H; Linz, Simone

2018-01-01

A minimum hybridization network is a rooted phylogenetic network that displays two given rooted phylogenetic trees using a minimum number of reticulations. Previous mathematical work on their calculation has usually assumed the input trees to be bifurcating, correctly rooted, or that they both contain the same taxa. These assumptions do not hold in biological studies and "realistic" trees have multifurcations, are difficult to root, and rarely contain the same taxa. We present a new algorithm for computing minimum hybridization networks for a given pair of "realistic" rooted phylogenetic trees. We also describe how the algorithm might be used to improve the rooting of the input trees. We introduce the concept of "autumn trees", a nice framework for the formulation of algorithms based on the mathematics of "maximum acyclic agreement forests". While the main computational problem is hard, the run-time depends mainly on how different the given input trees are. In biological studies, where the trees are reasonably similar, our parallel implementation performs well in practice. The algorithm is available in our open source program Dendroscope 3, providing a platform for biologists to explore rooted phylogenetic networks. We demonstrate the utility of the algorithm using several previously studied data sets.

Predicting volume of distribution with decision tree-based regression methods using predicted tissue:plasma partition coefficients.

PubMed

Freitas, Alex A; Limbu, Kriti; Ghafourian, Taravat

2015-01-01

Volume of distribution is an important pharmacokinetic property that indicates the extent of a drug's distribution in the body tissues. This paper addresses the problem of how to estimate the apparent volume of distribution at steady state (Vss) of chemical compounds in the human body using decision tree-based regression methods from the area of data mining (or machine learning). Hence, the pros and cons of several different types of decision tree-based regression methods have been discussed. The regression methods predict Vss using, as predictive features, both the compounds' molecular descriptors and the compounds' tissue:plasma partition coefficients (Kt:p) - often used in physiologically-based pharmacokinetics. Therefore, this work has assessed whether the data mining-based prediction of Vss can be made more accurate by using as input not only the compounds' molecular descriptors but also (a subset of) their predicted Kt:p values. Comparison of the models that used only molecular descriptors, in particular, the Bagging decision tree (mean fold error of 2.33), with those employing predicted Kt:p values in addition to the molecular descriptors, such as the Bagging decision tree using adipose Kt:p (mean fold error of 2.29), indicated that the use of predicted Kt:p values as descriptors may be beneficial for accurate prediction of Vss using decision trees if prior feature selection is applied. Decision tree based models presented in this work have an accuracy that is reasonable and similar to the accuracy of reported Vss inter-species extrapolations in the literature. The estimation of Vss for new compounds in drug discovery will benefit from methods that are able to integrate large and varied sources of data and flexible non-linear data mining methods such as decision trees, which can produce interpretable models. Graphical AbstractDecision trees for the prediction of tissue partition coefficient and volume of distribution of drugs.

A hierarchical structure for automatic meshing and adaptive FEM analysis

NASA Technical Reports Server (NTRS)

Kela, Ajay; Saxena, Mukul; Perucchio, Renato

1987-01-01

A new algorithm for generating automatically, from solid models of mechanical parts, finite element meshes that are organized as spatially addressable quaternary trees (for 2-D work) or octal trees (for 3-D work) is discussed. Because such meshes are inherently hierarchical as well as spatially addressable, they permit efficient substructuring techniques to be used for both global analysis and incremental remeshing and reanalysis. The global and incremental techniques are summarized and some results from an experimental closed loop 2-D system in which meshing, analysis, error evaluation, and remeshing and reanalysis are done automatically and adaptively are presented. The implementation of 3-D work is briefly discussed.

REAR ELEVATION WITH BASE OF PALM TREE IN FOREGROUND. VIEW ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

REAR ELEVATION WITH BASE OF PALM TREE IN FOREGROUND. VIEW FACING NORTH/NORTHEAST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Three-Bedroom Single-Family Type 9, Birch Circle, Elm Drive, Elm Circle, and Date Drive, Pearl City, Honolulu County, HI

VIEW OF REAR YARD WITH PLUMERIA TREES AND SMALL PALMS. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

VIEW OF REAR YARD WITH PLUMERIA TREES AND SMALL PALMS. VIEW FACING EAST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Three-Bedroom Single-Family Types 8 and 11, Birch Circle, Elm Drive, Elm Circle, and Date Drive, Pearl City, Honolulu County, HI

Reconstructing missing daily precipitation data using regression trees and artificial neural networks

USDA-ARS?s Scientific Manuscript database

Incomplete meteorological data has been a problem in environmental modeling studies. The objective of this work was to develop a technique to reconstruct missing daily precipitation data in the central part of Chesapeake Bay Watershed using regression trees (RT) and artificial neural networks (ANN)....

Reconstructing missing daily precipitation data using regression trees and artificial neural networks

USDA-ARS?s Scientific Manuscript database

Missing meteorological data have to be estimated for agricultural and environmental modeling. The objective of this work was to develop a technique to reconstruct the missing daily precipitation data in the central part of the Chesapeake Bay Watershed using regression trees (RT) and artificial neura...

New perspectives on the ecology of tree structure and tree communities through terrestrial laser scanning.

PubMed

Malhi, Yadvinder; Jackson, Tobias; Patrick Bentley, Lisa; Lau, Alvaro; Shenkin, Alexander; Herold, Martin; Calders, Kim; Bartholomeus, Harm; Disney, Mathias I

2018-04-06

Terrestrial laser scanning (TLS) opens up the possibility of describing the three-dimensional structures of trees in natural environments with unprecedented detail and accuracy. It is already being extensively applied to describe how ecosystem biomass and structure vary between sites, but can also facilitate major advances in developing and testing mechanistic theories of tree form and forest structure, thereby enabling us to understand why trees and forests have the biomass and three-dimensional structure they do. Here we focus on the ecological challenges and benefits of understanding tree form, and highlight some advances related to capturing and describing tree shape that are becoming possible with the advent of TLS. We present examples of ongoing work that applies, or could potentially apply, new TLS measurements to better understand the constraints on optimization of tree form. Theories of resource distribution networks, such as metabolic scaling theory, can be tested and further refined. TLS can also provide new approaches to the scaling of woody surface area and crown area, and thereby better quantify the metabolism of trees. Finally, we demonstrate how we can develop a more mechanistic understanding of the effects of avoidance of wind risk on tree form and maximum size. Over the next few years, TLS promises to deliver both major empirical and conceptual advances in the quantitative understanding of trees and tree-dominated ecosystems, leading to advances in understanding the ecology of why trees and ecosystems look and grow the way they do.

Pollen Competition as a Reproductive Isolation Barrier Represses Transgene Flow between Compatible and Co-Flowering Citrus Genotypes

PubMed Central

Pons, Elsa; Navarro, Antonio; Ollitrault, Patrick; Peña, Leandro

2011-01-01

Background/Objective Despite potential benefits granted by genetically modified (GM) fruit trees, their release and commercialization raises concerns about their potential environmental impact, and the transfer via pollen of transgenes to cross-compatible cultivars is deemed to be the greatest source for environmental exposure. Information compiled from field trials on GM trees is essential to propose measures to minimize the transgene dispersal. We have conducted a field trial of seven consecutive years to investigate the maximum frequency of pollen-mediated crop-to-crop transgene flow in a citrus orchard, and its relation to the genetic, phenological and environmental factors involved. Methodology/Principal Findings Three different citrus genotypes carrying the uidA (GUS) tracer marker gene (pollen donors) and a non-GM self-incompatible contiguous citrus genotype (recipient) were used in conditions allowing natural entomophilous pollination to occur. The examination of 603 to 2990 seeds per year showed unexpectedly low frequencies (0.17–2.86%) of transgene flow. Paternity analyses of the progeny of subsets of recipient plants using 10 microsatellite (SSR) loci demonstrated a higher mating competence of trees from another non-GM pollen source population that greatly limited the mating chance of the contiguous cross-compatible and flowering-synchronized transgenic pollen source. This mating superiority could be explained by a much higher pollen competition capacity of the non-GM genotypes, as was confirmed through mixed-hand pollinations. Conclusions/Significance Pollen competition strongly contributed to transgene confinement. Based on this finding, suitable isolation measures are proposed for the first time to prevent transgene outflow between contiguous plantings of citrus types that may be extendible to other entomophilous transgenic fruit tree species. PMID:21991359

Pollination and Plant Resources Change the Nutritional Quality of Almonds for Human Health

PubMed Central

Brittain, Claire; Kremen, Claire; Garber, Andrea; Klein, Alexandra-Maria

2014-01-01

Insect-pollinated crops provide important nutrients for human health. Pollination, water and nutrients available to crops can influence yield, but it is not known if the nutritional value of the crop is also influenced. Almonds are an important source of critical nutrients for human health such as unsaturated fat and vitamin E. We manipulated the pollination of almond trees and the resources available to the trees, to investigate the impact on the nutritional composition of the crop. The pollination treatments were: (a) exclusion of pollinators to initiate self-pollination and (b) hand cross-pollination; the plant resource treatments were: (c) reduced water and (d) no fertilizer. In an orchard in northern California, trees were exposed to a single treatment or a combination of two (one pollination and one resource). Both the fat and vitamin E composition of the nuts were highly influenced by pollination. Lower proportions of oleic to linoleic acid, which are less desirable from both a health and commercial perspective, were produced by the self-pollinated trees. However, higher levels of vitamin E were found in the self-pollinated nuts. In some cases, combined changes in pollination and plant resources sharpened the pollination effects, even when plant resources were not influencing the nutrients as an individual treatment. This study highlights the importance of insects as providers of cross-pollination for fruit quality that can affect human health, and, for the first time, shows that other environmental factors can sharpen the effect of pollination. This contributes to an emerging field of research investigating the complexity of interactions of ecosystem services affecting the nutritional value and commercial quality of crops. PMID:24587215

Pollen competition as a reproductive isolation barrier represses transgene flow between compatible and co-flowering citrus genotypes.

PubMed

Pons, Elsa; Navarro, Antonio; Ollitrault, Patrick; Peña, Leandro

2011-01-01

Despite potential benefits granted by genetically modified (GM) fruit trees, their release and commercialization raises concerns about their potential environmental impact, and the transfer via pollen of transgenes to cross-compatible cultivars is deemed to be the greatest source for environmental exposure. Information compiled from field trials on GM trees is essential to propose measures to minimize the transgene dispersal. We have conducted a field trial of seven consecutive years to investigate the maximum frequency of pollen-mediated crop-to-crop transgene flow in a citrus orchard, and its relation to the genetic, phenological and environmental factors involved. Three different citrus genotypes carrying the uidA (GUS) tracer marker gene (pollen donors) and a non-GM self-incompatible contiguous citrus genotype (recipient) were used in conditions allowing natural entomophilous pollination to occur. The examination of 603 to 2990 seeds per year showed unexpectedly low frequencies (0.17-2.86%) of transgene flow. Paternity analyses of the progeny of subsets of recipient plants using 10 microsatellite (SSR) loci demonstrated a higher mating competence of trees from another non-GM pollen source population that greatly limited the mating chance of the contiguous cross-compatible and flowering-synchronized transgenic pollen source. This mating superiority could be explained by a much higher pollen competition capacity of the non-GM genotypes, as was confirmed through mixed-hand pollinations. Pollen competition strongly contributed to transgene confinement. Based on this finding, suitable isolation measures are proposed for the first time to prevent transgene outflow between contiguous plantings of citrus types that may be extendible to other entomophilous transgenic fruit tree species.

Determining preventability of pediatric readmissions using fault tree analysis.

PubMed

Jonas, Jennifer A; Devon, Erin Pete; Ronan, Jeanine C; Ng, Sonia C; Owusu-McKenzie, Jacqueline Y; Strausbaugh, Janet T; Fieldston, Evan S; Hart, Jessica K

2016-05-01

Previous studies attempting to distinguish preventable from nonpreventable readmissions reported challenges in completing reviews efficiently and consistently. (1) Examine the efficiency and reliability of a Web-based fault tree tool designed to guide physicians through chart reviews to a determination about preventability. (2) Investigate root causes of general pediatrics readmissions and identify the percent that are preventable. General pediatricians from The Children's Hospital of Philadelphia used a Web-based fault tree tool to classify root causes of all general pediatrics 15-day readmissions in 2014. The tool guided reviewers through a logical progression of questions, which resulted in 1 of 18 root causes of readmission, 8 of which were considered potentially preventable. Twenty percent of cases were cross-checked to measure inter-rater reliability. Of the 7252 discharges, 248 were readmitted, for an all-cause general pediatrics 15-day readmission rate of 3.4%. Of those readmissions, 15 (6.0%) were deemed potentially preventable, corresponding to 0.2% of total discharges. The most common cause of potentially preventable readmissions was premature discharge. For the 50 cross-checked cases, both reviews resulted in the same root cause for 44 (86%) of files (κ = 0.79; 95% confidence interval: 0.60-0.98). Completing 1 review using the tool took approximately 20 minutes. The Web-based fault tree tool helped physicians to identify root causes of hospital readmissions and classify them as either preventable or not preventable in an efficient and consistent way. It also confirmed that only a small percentage of general pediatrics 15-day readmissions are potentially preventable. Journal of Hospital Medicine 2016;11:329-335. © 2016 Society of Hospital Medicine. © 2016 Society of Hospital Medicine.

Polyploidy in the Olive Complex (Olea europaea): Evidence from Flow Cytometry and Nuclear Microsatellite Analyses

PubMed Central

Besnard, G.; Garcia-Verdugo, C.; Rubio De Casas, R.; Treier, U. A.; Galland, N.; Vargas, P.

2008-01-01

Background Phylogenetic and phylogeographic investigations have been previously performed to study the evolution of the olive tree complex (Olea europaea). A particularly high genomic diversity has been found in north-west Africa. However, to date no exhaustive study has been addressed to infer putative polyploidization events and their evolutionary significance in the diversification of the olive tree and its relatives. Methods Representatives of the six olive subspecies were investigated using (a) flow cytometry to estimate genome content, and (b) six highly variable nuclear microsatellites to assess the presence of multiple alleles at co-dominant loci. In addition, nine individuals from a controlled cross between two individuals of O. europaea subsp. maroccana were characterized with microsatellites to check for chromosome inheritance. Key Results Based on flow cytometry and genetic analyses, strong evidence for polyploidy was obtained in subspp. cerasiformis (tetraploid) and maroccana (hexaploid), whereas the other subspecies appeared to be diploids. Agreement between flow cytometry and genetic analyses gives an alternative approach to chromosome counting to determine ploidy level of trees. Lastly, abnormalities in chromosomes inheritance leading to aneuploid formation were revealed using microsatellite analyses in the offspring from the controlled cross in subsp. maroccana. Conclusions This study constitutes the first report for multiple polyploidy in olive tree relatives. Formation of tetraploids and hexaploids may have played a major role in the diversification of the olive complex in north-west Africa. The fact that polyploidy is found in narrow endemic subspecies from Madeira (subsp. cerasiformis) and the Agadir Mountains (subsp. maroccana) suggests that polyploidization has been favoured to overcome inbreeding depression. Lastly, based on previous phylogenetic analyses, we hypothesize that subsp. cerasiformis resulted from hybridization between ancestors of subspp. guanchica and europaea. PMID:18024415

Progress towards the use of publicly available data networks to conduct cross-scale historical reconstructions of carbon dynamics in US Drylands

NASA Astrophysics Data System (ADS)

Washington-Allen, R. A.; Landolt, K.; Emanuel, R. E.; Therrell, M. D.; Nagle, N.; Grissino-Mayer, H. D.; Poulter, B.

2016-12-01

Emergent scale properties of water-limited or Dryland ecosystem's carbon flux are unknown at spatial scales from local to global and time scales of 10 - 1000 years or greater. The width of a tree ring is a metric of production that has been correlated with the amount of precipitation. This relationship has been used to reconstruct rainfall and fire histories in the Drylands of the southwestern US. The normalized difference vegetation index (NDVI) is globally measured by selected satellite sensors and is highly correlated with the fraction of solar radiation which is absorbed for photosynthesis by plants (FPAR), as well as with vegetation biomass, net primary productivity (NPP), and tree ring width. Publicly available web-based archives of free NDVI and tree ring data exist and have allowed historical temporal reconstructions of carbon dynamics for the past 300 to 500 years. Climate and tree ring databases have been used to spatially reconstruct drought dynamics for the last 500 years in the western US. In 2007, we hypothesized that NDVI and tree ring width could be used to spatially reconstruct carbon dynamics in US Drylands. In 2015, we succeeded with a 300-year historical spatial reconstruction of NPP in California using a Blue Oak tree ring chronology. Online eddy covariance flux tower measures of NPP are well correlated with satellite measures of NPP. This suggests that net ecosystem exchange (NEE = NPP - soil Respiration) could be historically reconstructed across Drylands. Ongoing research includes 1) scaling historical spatial reconstruction to US Drylands, 2) comparing the use of single versus multiple tree ring species (r2 = 68) and 3) use of the eddy flux tower network, remote sensing, and tree ring data to historically spatially reconstruct Dryland NEE.

Coalescent-Based Analyses of Genomic Sequence Data Provide a Robust Resolution of Phylogenetic Relationships among Major Groups of Gibbons

PubMed Central

Shi, Cheng-Min; Yang, Ziheng

2018-01-01

Abstract The phylogenetic relationships among extant gibbon species remain unresolved despite numerous efforts using morphological, behavorial, and genetic data and the sequencing of whole genomes. A major challenge in reconstructing the gibbon phylogeny is the radiative speciation process, which resulted in extremely short internal branches in the species phylogeny and extensive incomplete lineage sorting with extensive gene-tree heterogeneity across the genome. Here, we analyze two genomic-scale data sets, with ∼10,000 putative noncoding and exonic loci, respectively, to estimate the species tree for the major groups of gibbons. We used the Bayesian full-likelihood method bpp under the multispecies coalescent model, which naturally accommodates incomplete lineage sorting and uncertainties in the gene trees. For comparison, we included three heuristic coalescent-based methods (mp-est, SVDQuartets, and astral) as well as concatenation. From both data sets, we infer the phylogeny for the four extant gibbon genera to be (Hylobates, (Nomascus, (Hoolock, Symphalangus))). We used simulation guided by the real data to evaluate the accuracy of the methods used. Astral, while not as efficient as bpp, performed well in estimation of the species tree even in presence of excessive incomplete lineage sorting. Concatenation, mp-est and SVDQuartets were unreliable when the species tree contains very short internal branches. Likelihood ratio test of gene flow suggests a small amount of migration from Hylobates moloch to H. pileatus, while cross-genera migration is absent or rare. Our results highlight the utility of coalescent-based methods in addressing challenging species tree problems characterized by short internal branches and rampant gene tree-species tree discordance. PMID:29087487

Ergonomic evaluation and comparison of wood harvesting systems in Northwest Russia.

PubMed

Gerasimov, Yuri; Sokolov, Anton

2014-03-01

A comparison of 14 currently applicable wood harvesting systems was assessed with respect to ergonomic point of view. For this purpose, the research method, based on the Hodges-Lehmann rule and the integrated work-severity rate of single machinery, was developed for ergonomic evaluation of cut-to-length, tree-length and full-tree harvesting systems. Altogether, about 130 different parameters of 36 units of equipment that impact on the ergonomics and work conditions were measured and estimated in interviews undertaken directly at forestry harvesting workplaces in 15 logging companies in the Republic of Karelia, Northwest Russia. Then the results were compared to the effective norms, and the degree of compliance with the stipulated values was determined. The estimates obtained for the degree of compliance were combined. This permits a direct comparison of the workload on forestry harvesting workers such as operators, lumberjacks and choker setters. In many respects, the current ergonomic standard is standard, except for the operators of cable skidders, chainsaws and choker settings. Visibility and work postures were considered to be the most critical features influencing the operator's performance. Problems still exist, despite the extensive development of cabs. The best working conditions in terms of harvesting systems were provided by "harvester + forwarder" in cut-to-length harvesting, and "feller-buncher + grapple skidder" in full-tree harvesting. The motor-manual tree-length harvesting performed with cable skidders showed the worst results in terms of ergonomics. Copyright © 2013 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Structural and Chemical Characterization of Hardwood from Tree Species with Applications as Bioenergy Feedstocks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Çetinkol, Özgül Persil; Smith-Moritz, Andreia M.; Cheng, Gang

2012-12-28

Eucalypt species are a group of flowering trees widely used in pulp production for paper manufacture. For several decades, the wood pulp industry has focused research and development efforts on improving yields, growth rates and pulp quality through breeding and the genetic improvement of key tree species. Recently, this focus has shifted from the production of high quality pulps to the investigation of the use of eucalypts as feedstocks for biofuel production. Here the structure and chemical composition of the heartwood and sapwood of Eucalyptus dunnii, E. globulus, E. pillularis, E. urophylla, an E. urophylla-E. grandis cross, Corymbia citriodora ssp.more » variegata, and Acacia mangium were compared using nuclear magnetic resonance spectroscopy (NMR), X-ray diffraction (XRD) and biochemical composition analysis. Some trends relating to these compositions were also identified by Fourier transform near infrared (FT-NIR) spectroscopy. These results will serve as a foundation for a more comprehensive database of wood properties that will help develop criteria for the selection of tree species for use as biorefinery feedstocks.« less

Structural and Chemical Characterization of Hardwood from Tree Species with Applications as Bioenergy Feedstocks

PubMed Central

Çetinkol, Özgül Persil; Smith-Moritz, Andreia M.; Cheng, Gang; Lao, Jeemeng; George, Anthe; Hong, Kunlun; Henry, Robert; Simmons, Blake A.; Heazlewood, Joshua L.; Holmes, Bradley M.

2012-01-01

Eucalypt species are a group of flowering trees widely used in pulp production for paper manufacture. For several decades, the wood pulp industry has focused research and development efforts on improving yields, growth rates and pulp quality through breeding and the genetic improvement of key tree species. Recently, this focus has shifted from the production of high quality pulps to the investigation of the use of eucalypts as feedstocks for biofuel production. Here the structure and chemical composition of the heartwood and sapwood of Eucalyptus dunnii, E. globulus, E. pillularis, E. urophylla, an E. urophylla-E. grandis cross, Corymbia citriodora ssp. variegata, and Acacia mangium were compared using nuclear magnetic resonance spectroscopy (NMR), X-ray diffraction (XRD) and biochemical composition analysis. Some trends relating to these compositions were also identified by Fourier transform near infrared (FT-NIR) spectroscopy. These results will serve as a foundation for a more comprehensive database of wood properties that will help develop criteria for the selection of tree species for use as biorefinery feedstocks. PMID:23300786

Differential consumption of eastern red cedar (Juniperus virginiana) by avian and mammalian guilds: Implications for tree invasion

USGS Publications Warehouse

Horncastle, V.J.; Hellgren, E.C.; Mayer, P.M.; Engle, David M.; Leslie, D.M.

2004-01-01

Increased abundance and distribution of eastern redcedar (Juniperns virginiannus), a native 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 red cedar cones is essential to understanding the invasive spread of the species. We examined animal removal of cedar cones in three habitats (tallgrass prairie, eastern red cedar and woodland-prairie margins) in the Cross Timbers ecoregion using three exclosure treatments during autumn and winter. Exclosure treatments excluded study trees from ungulates, from terrestrial rodents and ungulates or from neither (control). Loss of cones from branches varied by a habitat-time interaction, but was not affected by exclosure type. Loss of cones from containers located under experimental trees varied by a habitat-treatment-time interaction. In December and January, cone consumption from containers in no-exclosure treatments was highest in margins, followed by tallgrass prairie and eastern red cedar habitats. We conclude birds consumed the majority of cones from branches and small-and medium-sized mammals consumed cones on the ground. Both birds and mammals likely contribute to the spread of eastern red cedar but at different scales. Limiting invasion of eastern red cedar in forests may require early detection and selective removal of pioneer seedlings in cross timbers and other habitats that attract a high diversity or density of frugivores.

Validation of tool mark analysis of cut costal cartilage.

PubMed

Love, Jennifer C; Derrick, Sharon M; Wiersema, Jason M; Peters, Charles

2012-03-01

This study was designed to establish the potential error rate associated with the generally accepted method of tool mark analysis of cut marks in costal cartilage. Three knives with different blade types were used to make experimental cut marks in costal cartilage of pigs. Each cut surface was cast, and each cast was examined by three analysts working independently. The presence of striations, regularity of striations, and presence of a primary and secondary striation pattern were recorded for each cast. The distance between each striation was measured. The results showed that striations were not consistently impressed on the cut surface by the blade's cutting edge. Also, blade type classification by the presence or absence of striations led to a 65% misclassification rate. Use of the classification tree and cross-validation methods and inclusion of the mean interstriation distance decreased the error rate to c. 50%. © 2011 American Academy of Forensic Sciences.

Cross amplification of 15 SSR markers in the genus Fraxinus

Treesearch

Andrea G. Noakes; Teodora Best; Margaret E. Stanton; Jennifer Koch; Jeanne Romero-Severson

2014-01-01

Ash (Fraxinus, Oleaceae) species occur on most continents, within a wide range of forest tree communities. Emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), introduced into the U.S. from Asia in the late twentieth century, has caused widespread mortality, primarily in green ash, Fraxinus...

Interspecific hybridizations in ornamental flowering cherries (Prunus species)

USDA-ARS?s Scientific Manuscript database

Flowering cherries belong to the genus Prunus L., consisting primarily of species native to Asia. Despite the popularity of ornamental cherry trees in the landscape, most ornamental Prunus planted in the U.S. are derived from a limited genetic base of Japanese flowering cherry taxa. Controlled cross...

DNA Profiles of MTG (Moderat Tahan Gano) Oil Palm Variety Based on SSR Marker

NASA Astrophysics Data System (ADS)

Putri, L. A. P.; Setiado, H.; Hardianti, R.

2017-03-01

The oil palm, an economically important tree in Indonesia, has been one of the world’s major sources of edible oil and a significant precursor of biodiesel fuel. The objectives of this study were to know DNA profile of commercial MTG (Moderat Tahan Gano) oil palm variety collections. A total of 10 trees MTG oil palm variety were used for analysis. In this experiment, the DNA profile diversity was assessed using mEgCIR0174 and SSR-1 loci of oil palm’s specific SSR markers. The results of the experiment indicated out of 3 alleles of pcr product of mEgCIR0174 (198, 203 and 208 bp) and SSR-1 (201, 217 and 232 bp). These preliminary results demonstrated SSR marker can be used to evaluate genetic relatedness among trees of MTG (Moderat Tahan Gano) oil palm variety derived from different crossing or difference to desease resistance trait or misslabeled.

Hybrid Surface Patterns Mimicking the Design of the Adhesive Toe Pad of Tree Frog.

PubMed

Xue, Longjian; Sanz, Belén; Luo, Aoyi; Turner, Kevin T; Wang, Xin; Tan, Di; Zhang, Rui; Du, Hang; Steinhart, Martin; Mijangos, Carmen; Guttmann, Markus; Kappl, Michael; Del Campo, Aránzazu

2017-10-24

Biological materials achieve directional reinforcement with oriented assemblies of anisotropic building blocks. One such example is the nanocomposite structure of keratinized epithelium on the toe pad of tree frogs, in which hexagonal arrays of (soft) epithelial cells are crossed by densely packed and oriented (hard) keratin nanofibrils. Here, a method is established to fabricate arrays of tree-frog-inspired composite micropatterns composed of polydimethylsiloxane (PDMS) micropillars embedded with polystyrene (PS) nanopillars. Adhesive and frictional studies of these synthetic materials reveal a benefit of the hierarchical and anisotropic design for both adhesion and friction, in particular, at high matrix-fiber interfacial strengths. The presence of PS nanopillars alters the stress distribution at the contact interface of micropillars and therefore enhances the adhesion and friction of the composite micropattern. The results suggest a design principle for bioinspired structural adhesives, especially for wet environments.

Hybrid Surface Patterns Mimicking the Design of the Adhesive Toe Pad of Tree Frog

PubMed Central

2017-01-01

Biological materials achieve directional reinforcement with oriented assemblies of anisotropic building blocks. One such example is the nanocomposite structure of keratinized epithelium on the toe pad of tree frogs, in which hexagonal arrays of (soft) epithelial cells are crossed by densely packed and oriented (hard) keratin nanofibrils. Here, a method is established to fabricate arrays of tree-frog-inspired composite micropatterns composed of polydimethylsiloxane (PDMS) micropillars embedded with polystyrene (PS) nanopillars. Adhesive and frictional studies of these synthetic materials reveal a benefit of the hierarchical and anisotropic design for both adhesion and friction, in particular, at high matrix–fiber interfacial strengths. The presence of PS nanopillars alters the stress distribution at the contact interface of micropillars and therefore enhances the adhesion and friction of the composite micropattern. The results suggest a design principle for bioinspired structural adhesives, especially for wet environments. PMID:28885831

DendroPy: a Python library for phylogenetic computing.

PubMed

Sukumaran, Jeet; Holder, Mark T

2010-06-15

DendroPy is a cross-platform library for the Python programming language that provides for object-oriented reading, writing, simulation and manipulation of phylogenetic data, with an emphasis on phylogenetic tree operations. DendroPy uses a splits-hash mapping to perform rapid calculations of tree distances, similarities and shape under various metrics. It contains rich simulation routines to generate trees under a number of different phylogenetic and coalescent models. DendroPy's data simulation and manipulation facilities, in conjunction with its support of a broad range of phylogenetic data formats (NEXUS, Newick, PHYLIP, FASTA, NeXML, etc.), allow it to serve a useful role in various phyloinformatics and phylogeographic pipelines. The stable release of the library is available for download and automated installation through the Python Package Index site (http://pypi.python.org/pypi/DendroPy), while the active development source code repository is available to the public from GitHub (http://github.com/jeetsukumaran/DendroPy).

Use of multi-frequency, multi-polarization, multi-angle airborne radars for class discrimination in a southern temperature forest

NASA Technical Reports Server (NTRS)

Mehta, N. C.

1984-01-01

The utility of radar scatterometers for discrimination and characterization of natural vegetation was investigated. Backscatter measurements were acquired with airborne multi-frequency, multi-polarization, multi-angle radar scatterometers over a test site in a southern temperate forest. Separability between ground cover classes was studied using a two-class separability measure. Very good separability is achieved between most classes. Longer wavelength is useful in separating trees from non-tree classes, while shorter wavelength and cross polarization are helpful for discrimination among tree classes. Using the maximum likelihood classifier, 50% overall classification accuracy is achieved using a single, short-wavelength scatterometer channel. Addition of multiple incidence angles and another radar band improves classification accuracy by 20% and 50%, respectively, over the single channel accuracy. Incorporation of a third radar band seems redundant for vegetation classification. Vertical transmit polarization is critically important for all classes.

Why Be a Shrub? A Basic Model and Hypotheses for the Adaptive Values of a Common Growth Form

PubMed Central

Götmark, Frank; Götmark, Elin; Jensen, Anna M.

2016-01-01

Shrubs are multi-stemmed short woody plants, more widespread than trees, important in many ecosystems, neglected in ecology compared to herbs and trees, but currently in focus due to their global expansion. We present a novel model based on scaling relationships and four hypotheses to explain the adaptive significance of shrubs, including a review of the literature with a test of one hypothesis. Our model describes advantages for a small shrub compared to a small tree with the same above-ground woody volume, based on larger cross-sectional stem area, larger area of photosynthetic tissue in bark and stem, larger vascular cambium area, larger epidermis (bark) area, and larger area for sprouting, and faster production of twigs and canopy. These components form our Hypothesis 1 that predicts higher growth rate for a small shrub than a small tree. This prediction was supported by available relevant empirical studies (14 publications). Further, a shrub will produce seeds faster than a tree (Hypothesis 2), multiple stems in shrubs insure future survival and growth if one or more stems die (Hypothesis 3), and three structural traits of short shrub stems improve survival compared to tall tree stems (Hypothesis 4)—all hypotheses have some empirical support. Multi-stemmed trees may be distinguished from shrubs by more upright stems, reducing bending moment. Improved understanding of shrubs can clarify their recent expansion on savannas, grasslands, and alpine heaths. More experiments and other empirical studies, followed by more elaborate models, are needed to understand why the shrub growth form is successful in many habitats. PMID:27507981

The characteristics of electrical trees in the inner and outer layers of different voltage rating XLPE cable insulation

NASA Astrophysics Data System (ADS)

Xie, Ansheng; Li, Shengtao; Zheng, Xiaoquan; Chen, George

2009-06-01

The statistical initiation and propagation characteristics of electrical trees in cross-linked polyethylene (XLPE) cables with different voltage ratings from 66 to 500 kV were investigated under a constant test voltage of 50 Hz/7 kV (the 66 kV rating cable is from UK, the others from China). It was found that the characteristics of electrical trees in the inner region of 66 kV cable insulation differed considerably from those in the outer region under the same test conditions; however, no significant differences appeared in the 110 kV rating cable and above. The initiation time of electrical trees in both the inner and the outer regions of the 66 kV cable is much shorter than that in higher voltage rating cables; in addition the growth rate of electrical trees in the 66 kV cable is much larger than that in the higher voltage rating cables. By using x-ray diffraction, differential scanning calorimetry and thermogravimetry methods, it was revealed that besides the extrusion process, the molecular weight of base polymer material and its distribution are the prime factors deciding the crystallization state. The crystallization state and the impurity content are responsible for the resistance to electrical trees. Furthermore, it was proposed that big spherulites will cooperate with high impurity content in enhancing the initiation and growth processes of electrical trees via the 'synergetic effect'. Finally, dense and small spherulites, high crystallinity, high purity level of base polymer material and super-clean production processes are desirable for higher voltage rating cables.

Comparison of different tree sap flow up-scaling procedures using Monte-Carlo simulations

NASA Astrophysics Data System (ADS)

Tatarinov, Fyodor; Preisler, Yakir; Roahtyn, Shani; Yakir, Dan

2015-04-01

An important task in determining forest ecosystem water balance is the estimation of stand transpiration, allowing separating evapotranspiration into transpiration and soil evaporation. This can be based on up-scaling measurements of sap flow in representative trees (SF), which can be done by different mathematical algorithms. The aim of the present study was to evaluate the error associated with different up-scaling algorithms under different conditions. Other types of errors (such as, measurement error, within tree SF variability, choice of sample plot etc.) were not considered here. A set of simulation experiments using Monte-Carlo technique was carried out and three up-scaling procedures were tested. (1) Multiplying mean stand sap flux density based on unit sapwood cross-section area (SFD) by total sapwood area (Klein et al, 2014); (2) deriving of linear dependence of tree sap flow on tree DBH and calculating SFstand using predicted SF by DBH classes and stand DBH distribution (Cermak et al., 2004); (3) same as method 2 but using non-linear dependency. Simulations were performed under different SFD(DBH) slope (bs, positive, negative, zero); different DBH and SFD standard deviations (Δd and Δs, respectively) and DBH class size. It was assumed that all trees in a unit area are measured and the total SF of all trees in the experimental plot was taken as the reference SFstand value. Under negative bs all models tend to overestimate SFstand and the error increases exponentially with decreasing bs. Under bs >0 all models tend to underestimate SFstand, but the error is much smaller than for bs

Time Lapse Electrical Resistivity to Connect Evapotranspiration and Groundwater Fluxes in the Critical Zone

NASA Astrophysics Data System (ADS)

Jarvis, S. K.; Harmon, R. E.; Barnard, H. R.; Randall, J.; Singha, K.

2017-12-01

The critical zone (CZ)—an open system extending from canopy top to the base of groundwater—is a highly dynamic and heterogeneous environment. In forested terrain, trees make up a large component of the CZ. This work aims to quantify the connection between vegetation and subsurface water storage at a hillslope scale within a forested watershed in the H.J. Andrews Experimental Forest, Oregon. To identify the mechanism(s) controlling the connection at the hillslope scale, we observe patterns in electrical conductivity using 2D-time lapse-DC resistivity. To compare inversions through time a representative error model was determined using L-curve criterion. Inverted data show high spatial variability in ground electrical conductivity and variation at both diel and seasonal timescales. These changes are most pronounced in areas corresponding to dense vegetation. The diel pattern in electrical conductivity is also observed in monitored sap flow sensors, water-level gauges, tensiometers, and sediment thermal probes. To quantify the temporal connection between these data over the course of the growing season a cross correlation analysis was conducted. Preliminary data show that over the course of the growing season transpiration becomes decoupled from both groundwater and soil moisture. Further decomposition of the inverted time lapse data will highlight spatial variability in electrical conductivity providing insight into the where, when, and how(s) of tree-modified subsurface storage.

Incompletely resolved phylogenetic trees inflate estimates of phylogenetic conservatism.

PubMed

Davies, T Jonathan; Kraft, Nathan J B; Salamin, Nicolas; Wolkovich, Elizabeth M

2012-02-01

The tendency for more closely related species to share similar traits and ecological strategies can be explained by their longer shared evolutionary histories and represents phylogenetic conservatism. How strongly species traits co-vary with phylogeny can significantly impact how we analyze cross-species data and can influence our interpretation of assembly rules in the rapidly expanding field of community phylogenetics. Phylogenetic conservatism is typically quantified by analyzing the distribution of species values on the phylogenetic tree that connects them. Many phylogenetic approaches, however, assume a completely sampled phylogeny: while we have good estimates of deeper phylogenetic relationships for many species-rich groups, such as birds and flowering plants, we often lack information on more recent interspecific relationships (i.e., within a genus). A common solution has been to represent these relationships as polytomies on trees using taxonomy as a guide. Here we show that such trees can dramatically inflate estimates of phylogenetic conservatism quantified using S. P. Blomberg et al.'s K statistic. Using simulations, we show that even randomly generated traits can appear to be phylogenetically conserved on poorly resolved trees. We provide a simple rarefaction-based solution that can reliably retrieve unbiased estimates of K, and we illustrate our method using data on first flowering times from Thoreau's woods (Concord, Massachusetts, USA).

Climate influences the leaf area/sapwood area ratio in Scots pine.

PubMed

Mencuccini, M; Grace, J

1995-01-01

We tested the hypothesis that the leaf area/sapwood area ratio in Scots pine (Pinus sylvestris L.) is influenced by site differences in water vapor pressure deficit of the air (D). Two stands of the same provenance were selected, one in western Scotland and one in eastern England, so that effects resulting from age, genetic variability, density and fertility were minimized. Compared with the Scots pine trees at the cooler and wetter site in Scotland, the trees at the warmer and drier site in England produced less leaf area per unit of conducting sapwood area both at a stem height of 1.3 m and at the base of the live crown, whereas stem permeability was similar at both sites. Also, trees at the drier site had less leaf area per unit branch cross-sectional area at the branch base than trees at the wetter site. For each site, the average values for leaf area, sapwood area and permeability were used, together with values of transpiration rates at different D, to calculate average stem water potential gradients. Changes in the leaf area/sapwood area ratio acted to maintain a similar water potential gradient in the stems of trees at both sites despite climatic differences between the sites.

Mapping standing dead trees (snags) in the aftermath of the 2013 Rim Fire using airborne LiDAR data.

NASA Astrophysics Data System (ADS)

Casas Planes, Á.; Garcia-Alonso, M.; Koltunov, A.; Ustin, S.; Falk, M.; Ramirez, C.; Siegel, R.

2014-12-01

Abundance and spatial distribution of standing dead trees (snags) are key indicators of forest biodiversity and ecosystem health and represent a critical component of habitat for various wildlife species, including the great grey owl and the black-backed woodpecker. In this work we assess the potential of light detection and ranging (LiDAR) to discriminate snags from the live trees and map their distribution. The study area encompasses the burn perimeter of the Rim Fire, the third largest wildfire in California's recorded history (~104.000 ha) and represents a heterogeneous mosaic of mixed conifer forests, hardwood, and meadows. The snags mapping procedure is based on a 3D single tree detection using a Watershed algorithm and the extraction of height and intensity metrics within each segment. Variables selected using Gaussian processes form a feature space for a classifier to distinguish between dead trees and live trees. Finally, snag density and snag diameter classes that are relevant for avian species are mapped. This work shows the use of LiDAR metrics to quantify ecological variables related to the vertical heterogeneity of the forest canopy that are important in the identification of snags, for example, fractional cover. We observed that intensity-related variables are critical to the successful identification of snags and their distribution. Our study highlights the importance of high-density LiDAR for characterizing the forest structural variables that contribute to the assessment of wildlife habitat suitability.

29 CFR 553.212 - Twenty percent limitation on nonexempt work.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Twenty percent limitation on nonexempt work. (a) Employees engaged in fire protection or law enforcement... example, firefighters who work for forest conservation agencies may, during slack times, plant trees and... of the total hours worked by that employee during the workweek or applicable work period. A person...

Tree planting experiences in the eastern interior coal province

Treesearch

Charles Medvick

1980-01-01

Fruit trees were planted successfully in 1918 and organized afforestation began in 1928. Professional foresters had a hand in some of the very earliest planting projects. Formal reclamation research played an important role in applying science to early reclamation technology; however, considerable work has preceded the scientists. Some success has been experienced with...

Improved Sanitation Practice for Control of Dutch Elm Disease

Treesearch

Jack H. Barger

1977-01-01

In Detroit, Michigan, 12 plots, each containing about 600 American elm trees, Ulmus americana L., were subjected for 3 years to intensive and conventional sanitation treatments to control Dutch elm disease. In the intensive treatment, three disease surveys were conducted each year; each followed by tree removal within 20 working days. In the...

Social and biophysical variation in regional timber harvest regimes

Treesearch

Jonathan R. Thompson; Charles D. Canham; Luca Morreale; David B. Kittredge; Brett Butler

2017-01-01

In terms of adult tree mortality, harvesting is the most prevalent disturbance in northeastern United States forests. Previous studies have demonstrated that stand structure and tree species composition are important predictors of harvest. We extend this work to investigate how social factors further influence harvest regimes. By coupling the Forest Inventory and...

Filling the gap: improving estimates of working tree resources in agricultural landscapes

Treesearch

C.H. Perry; C.W. Woodall; G.C. Liknes; M.M. Schoeneberger

2008-01-01

Agroforestry plantings and other trees intentionally established in rural and urban areas are emerging as innovative management options for addressing resource issues and achieving landscapelevel goals. An understanding of the ecosystem services contributed by these and future plantings would provide critical information to policy and program developers, and a...

Maintaining saproxylic insects in Canada's extensively managed boreal forests: a review

Treesearch

David W. Langor; John R. Spence; H.E. James Hammond; Joshua Jacobs; Tyler P. Cobb

2006-01-01

Recent work on saproxylic insect assemblages in western Canadian boreal forests has demonstrated high faunal diversity and variability, and that adequate assessment of these insects involves significant sampling and taxonomic challenges. Some major determinants of assemblage structure include tree species, degree of decay, stand age and cause of tree death. Experiments...

World directory of forest geneticists and tree breeders

Treesearch

F. Thomas Ledig; David B. Neale

1998-01-01

A formal task of the Forest Genetic Resources Study Group/North American Forestry Commission/Food and Agriculture Organization of the United Nations and Working Party 2.04.09 / Division 2- Physiology and Genetics / International Union of Forest ResearchOrganizations, this international directory lists more than 1,800 forest geneticists and tree breeders from 86...

Parks, Trees, and Environmental Justice: Field Notes from Washington, DC

ERIC Educational Resources Information Center

Buckley, Geoffrey L.; Whitmer, Ali; Grove, J. Morgan

2013-01-01

Students enrolled in a graduate seminar benefited in multiple ways from an intensive 3-day field trip to Washington, DC. Constructed around the theme of environmental justice, the trip gave students a chance to learn about street tree distribution, park quality, and racial segregation "up close." Working with personnel from the United…

Multi-focus image fusion based on area-based standard deviation in dual tree contourlet transform domain

NASA Astrophysics Data System (ADS)

Dong, Min; Dong, Chenghui; Guo, Miao; Wang, Zhe; Mu, Xiaomin

2018-04-01

Multiresolution-based methods, such as wavelet and Contourlet are usually used to image fusion. This work presents a new image fusion frame-work by utilizing area-based standard deviation in dual tree Contourlet trans-form domain. Firstly, the pre-registered source images are decomposed with dual tree Contourlet transform; low-pass and high-pass coefficients are obtained. Then, the low-pass bands are fused with weighted average based on area standard deviation rather than the simple "averaging" rule. While the high-pass bands are merged with the "max-absolute' fusion rule. Finally, the modified low-pass and high-pass coefficients are used to reconstruct the final fused image. The major advantage of the proposed fusion method over conventional fusion is the approximately shift invariance and multidirectional selectivity of dual tree Contourlet transform. The proposed method is compared with wavelet- , Contourletbased methods and other the state-of-the art methods on common used multi focus images. Experiments demonstrate that the proposed fusion framework is feasible and effective, and it performs better in both subjective and objective evaluation.

Trimming the UCERF2 hazard logic tree

USGS Publications Warehouse

Porter, Keith A.; Field, Edward H.; Milner, Kevin

2012-01-01

The Uniform California Earthquake Rupture Forecast 2 (UCERF2) is a fully time‐dependent earthquake rupture forecast developed with sponsorship of the California Earthquake Authority (Working Group on California Earthquake Probabilities [WGCEP], 2007; Field et al., 2009). UCERF2 contains 480 logic‐tree branches reflecting choices among nine modeling uncertainties in the earthquake rate model shown in Figure 1. For seismic hazard analysis, it is also necessary to choose a ground‐motion‐prediction equation (GMPE) and set its parameters. Choosing among four next‐generation attenuation (NGA) relationships results in a total of 1920 hazard calculations per site. The present work is motivated by a desire to reduce the computational effort involved in a hazard analysis without understating uncertainty. We set out to assess which branching points of the UCERF2 logic tree contribute most to overall uncertainty, and which might be safely ignored (set to only one branch) without significantly biasing results or affecting some useful measure of uncertainty. The trimmed logic tree will have all of the original choices from the branching points that contribute significantly to uncertainty, but only one arbitrarily selected choice from the branching points that do not.

Scaling Erica arborea transpiration from trees up to the stand using auxiliary micrometeorological information in a wax myrtle-tree heath cloud forest (La Gomera, Canary Islands).

PubMed

Regalado, Carlos M; Ritter, Axel

2013-09-01

We investigate evapotranspiration, sap flow and top soil water content variations in a wax myrtle-tree heath ('fayal-brezal' in Spanish) cloud forest in the Garajonay National Park (La Gomera, Canary Islands) over a 1-year period. We provide transpiration estimates for one of the representative species, the shrubby needle-like Erica arborea L., present in this relict subtropical forest. An ad hoc tree up to the stand scaling method that combines the sap flow and auxiliary reference evapotranspiration data is illustrated, showing to be useful when sap flow in a limited number of trees has been monitored. Individual daily-based scaling curves of the Gompertz type were necessary to explain the observed sap flow variability in E. arborea during the 1-year period investigated (r(2) ≥ 0.953 with mode of r(2) = 0.9999). The mean daily sap flow of an E. arborea individual amounted to 8.37 ± 5.65 kg day(-1) tree(-1), with a maximum of 20.48 kg day(-1) tree(-1), yielding an annual total of 3052.89 kg tree(-1). A comparison of the computed daily transpiration with the continuous micrometeorological time series monitored in the studied plot suggested that solar radiation was the main driving force of transpiration in E. arborea (cross correlation index = 0.94). Fog may also affect tree transpiration via its reduction of radiation and temperature, such that during foggy periods the mean daily water loss estimate of E. arborea was 5.35 ± 4.30 kg day(-1) tree(-1), which sharply contrasted with the 2.4-fold average transpiration values obtained for fog-free days, i.e., 12.81 ± 4.33 kg day(-1) tree(-1). The annual water balance rendered a 288 mm year(-1) water input to the forest and evidenced the need for accurately quantifying the contribution of fog water dripping from the canopy.

Individual tree crown approach for predicting site index in boreal forests using airborne laser scanning and hyperspectral data

NASA Astrophysics Data System (ADS)

Kandare, Kaja; Ørka, Hans Ole; Dalponte, Michele; Næsset, Erik; Gobakken, Terje

2017-08-01

Site productivity is essential information for sustainable forest management and site index (SI) is the most common quantitative measure of it. The SI is usually determined for individual tree species based on tree height and the age of the 100 largest trees per hectare according to stem diameter. The present study aimed to demonstrate and validate a methodology for the determination of SI using remotely sensed data, in particular fused airborne laser scanning (ALS) and airborne hyperspectral data in a forest site in Norway. The applied approach was based on individual tree crown (ITC) delineation: tree species, tree height, diameter at breast height (DBH), and age were modelled and predicted at ITC level using 10-fold cross validation. Four dominant ITCs per 400 m2 plot were selected as input to predict SI at plot level for Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris L.). We applied an experimental setup with different subsets of dominant ITCs with different combinations of attributes (predicted or field-derived) for SI predictions. The results revealed that the selection of the dominant ITCs based on the largest DBH independent of tree species, predicted the SI with similar accuracy as ITCs matched with field-derived dominant trees (RMSE: 27.6% vs 23.3%). The SI accuracies were at the same level when dominant species were determined from the remotely sensed or field data (RMSE: 27.6% vs 27.8%). However, when the predicted tree age was used the SI accuracy decreased compared to field-derived age (RMSE: 27.6% vs 7.6%). In general, SI was overpredicted for both tree species in the mature forest, while there was an underprediction in the young forest. In conclusion, the proposed approach for SI determination based on ITC delineation and a combination of ALS and hyperspectral data is an efficient and stable procedure, which has the potential to predict SI in forest areas at various spatial scales and additionally to improve existing SI maps in Norway.

On the tree stability risk

NASA Astrophysics Data System (ADS)

Giambastiani, Yamuna; Preti, Federico; Errico, Alessandro; Penna, Daniele

2017-04-01

There is growing interest in developing models for predicting how root anchorage and tree bracing could influence tree stability. This work presents the results of different experiments aimed at evaluating the mechanical response of plate roots to pulling tests. Pulling tests have been executed with increasing soil water content and soil of different texture. Different types of tree bracing have been examined for evaluating its impact on plant stiffness. Root plate was anchored with different systems for evaluating the change in overturning resistance. The first results indicate that soil water content contributed to modify both the soil cohesion and the stabilizing forces. Wind effect, slope stability and root reinforcement could be better quantified by means of such a results.

Chaotic behavior of a spin-glass model on a Cayley tree

NASA Astrophysics Data System (ADS)

da Costa, F. A.; de Araújo, J. M.; Salinas, S. R.

2015-06-01

We investigate the phase diagram of a spin-1 Ising spin-glass model on a Cayley tree. According to early work of Thompson and collaborators, this problem can be formulated in terms of a set of nonlinear discrete recursion relations along the branches of the tree. Physically relevant solutions correspond to the attractors of these mapping equations. In the limit of infinite coordination of the tree, and for some choices of the model parameters, we make contact with findings for the phase diagram of more recently investigated versions of the Blume-Emery-Griffiths spin-glass model. In addition to the anticipated phases, we numerically characterize the existence of modulated and chaotic structures.

Tree cover in sub-Saharan Africa: rainfall and fire constrain forest and savanna as alternative stable states.

PubMed

Staver, A Carla; Archibald, Sally; Levin, Simon

2011-05-01

Savannas are known as ecosystems with tree cover below climate-defined equilibrium values. However, a predictive framework for understanding constraints on tree cover is lacking. We present (a) a spatially extensive analysis of tree cover and fire distribution in sub-Saharan Africa, and (b) a model, based on empirical results, demonstrating that savanna and forest may be alternative stable states in parts of Africa, with implications for understanding savanna distributions. Tree cover does not increase continuously with rainfall, but rather is constrained to low (<50%, "savanna") or high tree cover (>75%, "forest"). Intermediate tree cover rarely occurs. Fire, which prevents trees from establishing, differentiates high and low tree cover, especially in areas with rainfall between 1000 mm and 2000 mm. Fire is less important at low rainfall (<1000 mm), where rainfall limits tree cover, and at high rainfall (>2000 mm), where fire is rare. This pattern suggests that complex interactions between climate and disturbance produce emergent alternative states in tree cover. The relationship between tree cover and fire was incorporated into a dynamic model including grass, savanna tree saplings, and savanna trees. Only recruitment from sapling to adult tree varied depending on the amount of grass in the system. Based on our empirical analysis and previous work, fires spread only at tree cover of 40% or less, producing a sigmoidal fire probability distribution as a function of grass cover and therefore a sigmoidal sapling to tree recruitment function. This model demonstrates that, given relatively conservative and empirically supported assumptions about the establishment of trees in savannas, alternative stable states for the same set of environmental conditions (i.e., model parameters) are possible via a fire feedback mechanism. Integrating alternative stable state dynamics into models of biome distributions could improve our ability to predict changes in biome distributions and in carbon storage under climate and global change scenarios.

Stochastic modelling of tree architecture and biomass allocation: application to teak (Tectona grandis L. f.), a tree species with polycyclic growth and leaf neoformation.

PubMed

Tondjo, Kodjo; Brancheriau, Loïc; Sabatier, Sylvie; Kokutse, Adzo Dzifa; Kokou, Kouami; Jaeger, Marc; de Reffye, Philippe; Fourcaud, Thierry

2018-06-08

For a given genotype, the observed variability of tree forms results from the stochasticity of meristem functioning and from changing and heterogeneous environmental factors affecting biomass formation and allocation. In response to climate change, trees adapt their architecture by adjusting growth processes such as pre- and neoformation, as well as polycyclic growth. This is the case for the teak tree. The aim of this work was to adapt the plant model, GreenLab, in order to take into consideration both these processes using existing data on this tree species. This work adopted GreenLab formalism based on source-sink relationships at organ level that drive biomass production and partitioning within the whole plant over time. The stochastic aspect of phytomer production can be modelled by a Bernoulli process. The teak model was designed, parameterized and analysed using the architectural data from 2- to 5-year-old teak trees in open field stands. Growth and development parameters were identified, fitting the observed compound organic series with the theoretical series, using generalized least squares methods. Phytomer distributions of growth units and branching pattern varied depending on their axis category, i.e. their physiological age. These emerging properties were in accordance with the observed growth patterns and biomass allocation dynamics during a growing season marked by a short dry season. Annual growth patterns observed on teak, including shoot pre- and neoformation and polycyclism, were reproduced by the new version of the GreenLab model. However, further updating is discussed in order to ensure better consideration of radial variation in basic specific gravity of wood. Such upgrading of the model will enable teak ideotypes to be defined for improving wood production in terms of both volume and quality.

Growth and physiological responses of isohydric and anisohydric poplars to drought

Treesearch

Ziv Attia; Jean-Christophe Domec; Ram Oren; Danielle A. Way; Menachem Moshelion

2015-01-01

Understanding how different plants prioritize carbon gain and drought vulnerability under a variable water supply is important for predicting which trees will maximize woody biomass production under different environmental conditions. Here, Populus balsamifera (BS, isohydric genotype), P. simonii (SI, previously uncharacterized stomatal behaviour), and their cross, P....

The relationship between trees and human health: evidence from the spread of the emerald ash borer

Treesearch

Geoffrey H. Donovan; David T. Butry; Yvonne L. Michael; Jeffrey P. Prestemon; Andrew M. Liebhold; Demetrios Gatziolis; Megan Y. Mao

2013-01-01

Background: Several recent studies have identified a relationship between the natural environment and improved health outcomes. However, for practical reasons, most have been observational, cross-sectional studies.Purpose: A natural experiment, which provides stronger evidence of causality, was used to...

36 CFR 327.5 - Swimming.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 36 Parks, Forests, and Public Property 3 2014-07-01 2014-07-01 false Swimming. 327.5 Section 327.5 Parks, Forests, and Public Property CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY RULES AND REGULATIONS... activities. (c) Diving, jumping or swinging from trees, bridges or other structures which cross or are...

1. LOOKING TOWARD PLANE 9 WEST. BASIN HAS BEEN DRAINED ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. LOOKING TOWARD PLANE 9 WEST. BASIN HAS BEEN DRAINED AND SLOPE OF PLANE 9 IS VISIBLE BETWEEN ROW OF TREES IN BACKGROUND. STONEWORK ON LEFT IS ABUTMENT TO BRIDGE THAT CROSSED OVER THE CANAL. - Morris Canal, Inclined Plane 9 West, Port Warren, Warren County, NJ

Cross-Continental Reflections on Evaluation Practice: Methods, Use, and Valuing

ERIC Educational Resources Information Center

Kallemeyn, Leanne M.; Hall, Jori; Friche, Nanna; McReynolds, Clifton

2015-01-01

The evaluation theory tree typology reflects the following three components of evaluation practice: (a) methods, (b) use, and (c) valuing. The purpose of this study was to explore how evaluation practice is conceived as reflected in articles published in the "American Journal of Evaluation" ("AJE") and "Evaluation," a…

The Austrian x red pine hybrid

Treesearch

W. B. Critchfield

1963-01-01

The genetic improvement of red pine (Pinus resinosa Ait.) presents tree breeders with one of their most difficult problems. Not only is this valuable species remarkably uniform, but until 1955 it resisted all attempts to cross it with other pines. In that year red pine and Austrian pine (P. nigra var. austriaca [...

Benchmark datasets for phylogenomic pipeline validation, applications for foodborne pathogen surveillance.

PubMed

Timme, Ruth E; Rand, Hugh; Shumway, Martin; Trees, Eija K; Simmons, Mustafa; Agarwala, Richa; Davis, Steven; Tillman, Glenn E; Defibaugh-Chavez, Stephanie; Carleton, Heather A; Klimke, William A; Katz, Lee S

2017-01-01

As next generation sequence technology has advanced, there have been parallel advances in genome-scale analysis programs for determining evolutionary relationships as proxies for epidemiological relationship in public health. Most new programs skip traditional steps of ortholog determination and multi-gene alignment, instead identifying variants across a set of genomes, then summarizing results in a matrix of single-nucleotide polymorphisms or alleles for standard phylogenetic analysis. However, public health authorities need to document the performance of these methods with appropriate and comprehensive datasets so they can be validated for specific purposes, e.g., outbreak surveillance. Here we propose a set of benchmark datasets to be used for comparison and validation of phylogenomic pipelines. We identified four well-documented foodborne pathogen events in which the epidemiology was concordant with routine phylogenomic analyses (reference-based SNP and wgMLST approaches). These are ideal benchmark datasets, as the trees, WGS data, and epidemiological data for each are all in agreement. We have placed these sequence data, sample metadata, and "known" phylogenetic trees in publicly-accessible databases and developed a standard descriptive spreadsheet format describing each dataset. To facilitate easy downloading of these benchmarks, we developed an automated script that uses the standard descriptive spreadsheet format. Our "outbreak" benchmark datasets represent the four major foodborne bacterial pathogens ( Listeria monocytogenes , Salmonella enterica , Escherichia coli , and Campylobacter jejuni ) and one simulated dataset where the "known tree" can be accurately called the "true tree". The downloading script and associated table files are available on GitHub: https://github.com/WGS-standards-and-analysis/datasets. These five benchmark datasets will help standardize comparison of current and future phylogenomic pipelines, and facilitate important cross-institutional collaborations. Our work is part of a global effort to provide collaborative infrastructure for sequence data and analytic tools-we welcome additional benchmark datasets in our recommended format, and, if relevant, we will add these on our GitHub site. Together, these datasets, dataset format, and the underlying GitHub infrastructure present a recommended path for worldwide standardization of phylogenomic pipelines.

A comparison of the hydraulic efficiency of a palm species (Iriartea deltoidea) with other wood types.

PubMed

Renninger, Heidi J; McCulloh, Katherine A; Phillips, Nathan

2013-02-01

Palms are an important component of tropical ecosystems, living alongside dicotyledonous trees, even though they have a very different growth pattern and vascular system. As monocots, vessels in palms are located within vascular bundles and, without a vascular cambium that many dicotyledonous trees possess, palms cannot add additional vessels to their vascular system as they get older and taller. This means that hydraulic architecture in palms is more predetermined, which may require a highly efficient hydraulic system. This preset nature, along with the decoupling of hydraulic and mechanical functioning to different cell types, may allow palms to have a more efficient hydraulic system than dicotyledonous trees. Therefore, this study seeks to determine the efficiency of the hydraulic system in the palm Iriartea deltoidea (Ruiz & Pav.) and compare this efficiency with other tree forms. We measured cross-sectional areas of roots, stems and fronds as well as leaf areas of I. deltoidea saplings. Likewise, cross-sections were made and vessel diameters and frequencies measured. This allowed for the calculation of theoretical specific conductivity (K(S,calc)), theoretical leaf-specific conductivity (K(L,calc)), and vessel diameter and vessel number ratios between distal and proximal locations in the palms. Iriartea deltoidea palms were found to have the largest, least frequent vessels that diverged most from the square packing limit (maximum number of vessels that fit into a given area) compared with other major tree forms, and they therefore invested the least space and carbon into water transport structures. Likewise, conduits tapered by ∼1/3 between ranks (root, bole and petiole), which represents an efficient ratio with regard to the trade-offs between safety and efficiency of the conducting system. Conduits also exhibited a high conservation of the sum of the conduit radii cubed (Σr(3)) across ranks, thereby approximating Murray's law patterning. Therefore, our results indicate that the palm I. deltoidea has a very efficient hydraulic system in terms of maintaining a large conducting capacity with a minimal vascular investment. This efficiency may allow palms to compete well with dicotyledonous trees in tropical and subtropical climates but other developmental factors largely restrict palms from regions that experience prolonged freezing temperatures.

Combining Genome-Wide Information with a Functional Structural Plant Model to Simulate 1-Year-Old Apple Tree Architecture.

PubMed

Migault, Vincent; Pallas, Benoît; Costes, Evelyne

2016-01-01

In crops, optimizing target traits in breeding programs can be fostered by selecting appropriate combinations of architectural traits which determine light interception and carbon acquisition. In apple tree, architectural traits were observed to be under genetic control. However, architectural traits also result from many organogenetic and morphological processes interacting with the environment. The present study aimed at combining a FSPM built for apple tree, MAppleT, with genetic determinisms of architectural traits, previously described in a bi-parental population. We focused on parameters related to organogenesis (phyllochron and immediate branching) and morphogenesis processes (internode length and leaf area) during the first year of tree growth. Two independent datasets collected in 2004 and 2007 on 116 genotypes, issued from a 'Starkrimson' × 'Granny Smith' cross, were used. The phyllochron was estimated as a function of thermal time and sylleptic branching was modeled subsequently depending on phyllochron. From a genetic map built with SNPs, marker effects were estimated on four MAppleT parameters with rrBLUP, using 2007 data. These effects were then considered in MAppleT to simulate tree development in the two climatic conditions. The genome wide prediction model gave consistent estimations of parameter values with correlation coefficients between observed values and estimated values from SNP markers ranging from 0.79 to 0.96. However, the accuracy of the prediction model following cross validation schemas was lower. Three integrative traits (the number of leaves, trunk length, and number of sylleptic laterals) were considered for validating MAppleT simulations. In 2007 climatic conditions, simulated values were close to observations, highlighting the correct simulation of genetic variability. However, in 2004 conditions which were not used for model calibration, the simulations differed from observations. This study demonstrates the possibility of integrating genome-based information in a FSPM for a perennial fruit tree. It also showed that further improvements are required for improving the prediction ability. Especially temperature effect should be extended and other factors taken into account for modeling GxE interactions. Improvements could also be expected by considering larger populations and by testing other genome wide prediction models. Despite these limitations, this study opens new possibilities for supporting plant breeding by in silico evaluations of the impact of genotypic polymorphisms on plant integrative phenotypes.

Learning accurate very fast decision trees from uncertain data streams

NASA Astrophysics Data System (ADS)

Liang, Chunquan; Zhang, Yang; Shi, Peng; Hu, Zhengguo

2015-12-01

Most existing works on data stream classification assume the streaming data is precise and definite. Such assumption, however, does not always hold in practice, since data uncertainty is ubiquitous in data stream applications due to imprecise measurement, missing values, privacy protection, etc. The goal of this paper is to learn accurate decision tree models from uncertain data streams for classification analysis. On the basis of very fast decision tree (VFDT) algorithms, we proposed an algorithm for constructing an uncertain VFDT tree with classifiers at tree leaves (uVFDTc). The uVFDTc algorithm can exploit uncertain information effectively and efficiently in both the learning and the classification phases. In the learning phase, it uses Hoeffding bound theory to learn from uncertain data streams and yield fast and reasonable decision trees. In the classification phase, at tree leaves it uses uncertain naive Bayes (UNB) classifiers to improve the classification performance. Experimental results on both synthetic and real-life datasets demonstrate the strong ability of uVFDTc to classify uncertain data streams. The use of UNB at tree leaves has improved the performance of uVFDTc, especially the any-time property, the benefit of exploiting uncertain information, and the robustness against uncertainty.

Finding Frequent Closed Itemsets in Sliding Window in Linear Time

NASA Astrophysics Data System (ADS)

Chen, Junbo; Zhou, Bo; Chen, Lu; Wang, Xinyu; Ding, Yiqun

One of the most well-studied problems in data mining is computing the collection of frequent itemsets in large transactional databases. Since the introduction of the famous Apriori algorithm [14], many others have been proposed to find the frequent itemsets. Among such algorithms, the approach of mining closed itemsets has raised much interest in data mining community. The algorithms taking this approach include TITANIC [8], CLOSET+[6], DCI-Closed [4], FCI-Stream [3], GC-Tree [15], TGC-Tree [16] etc. Among these algorithms, FCI-Stream, GC-Tree and TGC-Tree are online algorithms work under sliding window environments. By the performance evaluation in [16], GC-Tree [15] is the fastest one. In this paper, an improved algorithm based on GC-Tree is proposed, the computational complexity of which is proved to be a linear combination of the average transaction size and the average closed itemset size. The algorithm is based on the essential theorem presented in Sect. 4.2. Empirically, the new algorithm is several orders of magnitude faster than the state of art algorithm, GC-Tree.

Predictive models for radial sap flux variation in coniferous, diffuse-porous and ring-porous temperate trees.

PubMed

Berdanier, Aaron B; Miniat, Chelcy F; Clark, James S

2016-08-01

Accurately scaling sap flux observations to tree or stand levels requires accounting for variation in sap flux between wood types and by depth into the tree. However, existing models for radial variation in axial sap flux are rarely used because they are difficult to implement, there is uncertainty about their predictive ability and calibration measurements are often unavailable. Here we compare different models with a diverse sap flux data set to test the hypotheses that radial profiles differ by wood type and tree size. We show that radial variation in sap flux is dependent on wood type but independent of tree size for a range of temperate trees. The best-fitting model predicted out-of-sample sap flux observations and independent estimates of sapwood area with small errors, suggesting robustness in the new settings. We develop a method for predicting whole-tree water use with this model and include computer code for simple implementation in other studies. Published by Oxford University Press 2016. This work is written by (a) US Government employee(s) and is in the public domain in the US.

A Laser Photoacoustic Analysis of Residual CO2 and H2O in Larch Stems

PubMed Central

Ageev, Boris; Ponomarev, Yurii; Sapozhnikova, Valeria; Savchuk, Dmitry

2014-01-01

Every so often, the results obtained from investigations into the effects of varying environmental conditions on the tree growth rate at the same sites and on the change in the carbon balance in plants, using traditional methods, are found to differ widely. We believe that the reason for the ambiguity of the data has to do with failure to account for the role of the residual CO2 (and H2O) in the tree wood exhibiting a climate response. In our earlier work, the results of a laser photoacoustic gas analysis of CO2 and H2O vacuum-desorbed from disc tree rings of evergreen conifer trees were presented. In this paper, laser photoacoustic measurements of tree ring gases in deciduous conifer trees and CO2 carbon isotope composition determined by means of a mass spectrometer are given. Conclusions are made regarding the response of annual larch CO2 disc tree ring distributions to climatic parameters (temperatures and precipitation). The data about the CO2 disc content for different sites are compared. PMID:25808838

Indigenous Community Tree Inventory: Assessment of Data Quality

NASA Astrophysics Data System (ADS)

Fauzi, M. F.; Idris, N. H.; Din, A. H. M.; Osman, M. J.; Idris, N. H.; Ishak, M. H. I.

2016-09-01

The citizen science program to supplement authoritative data in tree inventory has been well implemented in various countries. However, there is a lack of study that assesses correctness and accuracy of tree data supplied by citizens. This paper addresses the issue of tree data quality supplied by semi-literate indigenous group. The aim of this paper is to assess the correctness of attributes (tree species name, height and diameter at breast height) and the accuracy of tree horizontal positioning data supplied by indigenous people. The accuracy of the tree horizontal position recorded by GNSS-enable smart phone was found to have a RMSE value of ± 8m which is not suitable to accurately locate individual tree position in tropical rainforest such as the Royal Belum State Park. Consequently, the tree species names contributed by indigenous people were only 20 to 30 percent correct as compared with the reference data. However, the combination of indigenous respondents comprising of different ages, experience and knowledge working in a group influence less attribute error in data entry and increase the use of free text rather than audio methods. The indigenous community has a big potential to engage with scientific study due to their local knowledge with the research area, however intensive training must be given to empower their skills and several challenges need to be addressed.

Stand Structural Controls on Evapotranspiration in Native and Invaded Tropical Montane Cloud Forest in Hawai'i

NASA Astrophysics Data System (ADS)

Giambelluca, T. W.; Delay, J. K.; Asner, G. P.; Martin, R. E.; Nullet, M. A.; Huang, M.; Mudd, R. G.; Takahashi, M.

2008-12-01

Tropical montane cloud forests (TMCFs) in Hawai'i are important zones of water input and stores of critically important native plant and animal species. Invasion by alien tree species threatens these forests and may alter the hydrological services they provide. At two TMCF sites in Hawai'i, one within native Metrosideros polymorpha forest and the other at a site heavily invaded by Psidium cattleianum, we are conducting measurements of stand-level evapotranspiration (ET), transpiration (using sapflow techniques), energy balance, and related processes. Previously presented results showed that ET as a function of available energy was 27% higher at the invaded site than the native site, with the difference rising to 53% during dry- canopy periods. In this presentation, mechanisms for the observed higher ET rate at the invaded site are explored. The difference in measured xylem flow velocities of native and alien trees cannot explain the observed stand level ET difference. Tree basal area is lower at the invaded site than the native site, again contrary to the ET difference. However, the alien trees have much smaller stem diameters, on average, than the native trees, with little or no heartwood. Hence, the cross-sectional xylem area is much greater in the invaded stand, facilitating higher transpiration rates. These results demonstrate the importance of stand structural controls on ET and raise questions about whether higher ET is a transient feature of the succession or a persistent characteristic of invasive trees.

Monitoring individual tree-based change with airborne lidar.

PubMed

Duncanson, Laura; Dubayah, Ralph

2018-05-01

Understanding the carbon flux of forests is critical for constraining the global carbon cycle and managing forests to mitigate climate change. Monitoring forest growth and mortality rates is critical to this effort, but has been limited in the past, with estimates relying primarily on field surveys. Advances in remote sensing enable the potential to monitor tree growth and mortality across landscapes. This work presents an approach to measure tree growth and loss using multidate lidar campaigns in a high-biomass forest in California, USA. Individual tree crowns were delineated in 2008 and again in 2013 using a 3D crown segmentation algorithm, with derived heights and crown radii extracted and used to estimate individual tree aboveground biomass. Tree growth, loss, and aboveground biomass were analyzed with respect to tree height and crown radius. Both tree growth and loss rates decrease with increasing tree height, following the expectation that trees slow in growth rate as they age. Additionally, our aboveground biomass analysis suggests that, while the system is a net source of aboveground carbon, these carbon dynamics are governed by size class with the largest sources coming from the loss of a relatively small number of large individuals. This study demonstrates that monitoring individual tree-based growth and loss can be conducted with multidate airborne lidar, but these methods remain relatively immature. Disparities between lidar acquisitions were particularly difficult to overcome and decreased the sample of trees analyzed for growth rate in this study to 21% of the full number of delineated crowns. However, this study illuminates the potential of airborne remote sensing for ecologically meaningful forest monitoring at an individual tree level. As methods continue to improve, airborne multidate lidar will enable a richer understanding of the drivers of tree growth, loss, and aboveground carbon flux.

Interactive effects of work psychosocial factors on participation in workplace wellness programs.

PubMed

Sangachin, Mahboobeh Ghesmaty; Cavuoto, Lora A

2018-01-01

This study explored concurrent effects of six work psychosocial factors on current participation and the self-reported likelihood of future participation in workplace wellness programs using a cross-sectional survey, an ad hoc focus group, and structured interviews. Classification and regression tree analysis was used to analyze survey responses from 343 employees (194 nonparticipants, 95 participants, and 54 engaged participants). A thematic analysis of focus group ( n = 7) and interview ( n = 5) narratives was also undertaken. In combination with high work control, high superior support was associated with an engaged participant profile. Job demand was the third important variable with low and very high levels associated with participation. With regard to high likelihood of future participation, among respondents with age older than 50, high predictability of occupational activities and control were identified as a significant factor, and among others, high superior support and control. The analysis of narratives revealed peer relations and flexible working hours to be positively linked to participation and general job stress was identified as having a bidirectional relationship. Employees stated that stress led them to take advantage of these programs as a source of relief and that their availability/participation has contributed to lowering their stress. These findings inform practitioners about the importance of addressing poor psychosocial factors as a participation barrier and having a holistic approach to employee well-being.

A scalable approach for tree segmentation within small-footprint airborne LiDAR data

NASA Astrophysics Data System (ADS)

Hamraz, Hamid; Contreras, Marco A.; Zhang, Jun

2017-05-01

This paper presents a distributed approach that scales up to segment tree crowns within a LiDAR point cloud representing an arbitrarily large forested area. The approach uses a single-processor tree segmentation algorithm as a building block in order to process the data delivered in the shape of tiles in parallel. The distributed processing is performed in a master-slave manner, in which the master maintains the global map of the tiles and coordinates the slaves that segment tree crowns within and across the boundaries of the tiles. A minimal bias was introduced to the number of detected trees because of trees lying across the tile boundaries, which was quantified and adjusted for. Theoretical and experimental analyses of the runtime of the approach revealed a near linear speedup. The estimated number of trees categorized by crown class and the associated error margins as well as the height distribution of the detected trees aligned well with field estimations, verifying that the distributed approach works correctly. The approach enables providing information of individual tree locations and point cloud segments for a forest-level area in a timely manner, which can be used to create detailed remotely sensed forest inventories. Although the approach was presented for tree segmentation within LiDAR point clouds, the idea can also be generalized to scale up processing other big spatial datasets.

Displayed Trees Do Not Determine Distinguishability Under the Network Multispecies Coalescent

PubMed Central

Zhu, Sha; Degnan, James H.

2017-01-01

Abstract Recent work in estimating species relationships from gene trees has included inferring networks assuming that past hybridization has occurred between species. Probabilistic models using the multispecies coalescent can be used in this framework for likelihood-based inference of both network topologies and parameters, including branch lengths and hybridization parameters. A difficulty for such methods is that it is not always clear whether, or to what extent, networks are identifiable—that is whether there could be two distinct networks that lead to the same distribution of gene trees. For cases in which incomplete lineage sorting occurs in addition to hybridization, we demonstrate a new representation of the species network likelihood that expresses the probability distribution of the gene tree topologies as a linear combination of gene tree distributions given a set of species trees. This representation makes it clear that in some cases in which two distinct networks give the same distribution of gene trees when sampling one allele per species, the two networks can be distinguished theoretically when multiple individuals are sampled per species. This result means that network identifiability is not only a function of the trees displayed by the networks but also depends on allele sampling within species. We additionally give an example in which two networks that display exactly the same trees can be distinguished from their gene trees even when there is only one lineage sampled per species. PMID:27780899

Optimizing Use of Girdled Ash Trees for Management of Low-Density Emerald Ash Borer (Coleoptera: Buprestidae) Populations.

PubMed

Siegert, Nathan W; McCullough, Deborah G; Poland, Therese M; Heyd, Robert L

2017-06-01

Effective survey methods to detect and monitor recently established, low-density infestations of emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), remain a high priority because they provide land managers and property owners with time to implement tactics to slow emerald ash borer population growth and the progression of ash mortality. We evaluated options for using girdled ash (Fraxinus spp.) trees for emerald ash borer detection and management in a low-density infestation in a forested area with abundant green ash (F. pennsylvanica). Across replicated 4-ha plots, we compared detection efficiency of 4 versus 16 evenly distributed girdled ash trees and between clusters of 3 versus 12 girdled trees. We also examined within-tree larval distribution in 208 girdled and nongirdled trees and assessed adult emerald ash borer emergence from detection trees felled 11 mo after girdling and left on site. Overall, current-year larvae were present in 85-97% of girdled trees and 57-72% of nongirdled trees, and larval density was 2-5 times greater on girdled than nongirdled trees. Low-density emerald ash borer infestations were readily detected with four girdled trees per 4-ha, and 3-tree clusters were as effective as 12-tree clusters. Larval densities were greatest 0.5 ± 0.4 m below the base of the canopy in girdled trees and 1.3 ± 0.7 m above the canopy base in nongirdled trees. Relatively few adult emerald ash borer emerged from trees felled 11 mo after girdling and left on site through the following summer, suggesting removal or destruction of girdled ash trees may be unnecessary. This could potentially reduce survey costs, particularly in forested areas with poor accessibility. Published by Oxford University Press on behalf of Entomological Society of America 2017. This work is written by US Government employees and is in the public domain in the US.

Comparative Issues and Methods in Organizational Diagnosis. Report II. The Decision Tree Approach.

DTIC Science & Technology

organizational diagnosis . The advantages and disadvantages of the decision-tree approach generally, and in this study specifically, are examined. A pre-test, using a civilian sample of 174 work groups with Survey of Organizations data, was conducted to assess various decision-tree classification criteria, in terms of their similarity to the distance function used by Bowers and Hausser (1977). The results suggested the use of a large developmental sample, which should result in more distinctly defined boundary lines between classification profiles. Also, the decision matrix

Spatiotemporal throughfall patterns beneath an urban tree row

NASA Astrophysics Data System (ADS)

Bogeholz, P.; Van Stan, J. T., II; Hildebrandt, A.; Friesen, J.; Dibble, M.; Norman, Z.

2016-12-01

Much recent research has focused on throughfall patterns in natural forests as they can influence the heterogeneity of surface ecohydrological and biogeochemical processes. However, to the knowledge of the authors, no work has assessed how urban forest structures affect the spatiotemporal variability of throughfall water flux. Urbanization greatly alters not only a significant portion of the land surface, but canopy structure, with the most typical urban forest configuration being landscaped tree rows along streets, swales, parking lot medians, etc. This study examines throughfall spatiotemporal patterns for a landscaped tree row of Pinus elliottii (Engelm., slash pine) on Georgia Southern University's campus (southeastern, USA) using 150 individual observations per storm. Throughfall correlation lengths beneath this tree row were similar to, but appeared to be more stable across storm size than, observations in past studies on natural forests. Individual tree overlap and the planting interval also may more strongly drive throughfall patterns in tree rows. Meteorological influences beyond storm magnitude (intensity, intermittency, wind conditions, and atmospheric moisture demand) are also examined.

3D Tree Dimensionality Assessment Using Photogrammetry and Small Unmanned Aerial Vehicles

PubMed Central

2015-01-01

Detailed, precise, three-dimensional (3D) representations of individual trees are a prerequisite for an accurate assessment of tree competition, growth, and morphological plasticity. Until recently, our ability to measure the dimensionality, spatial arrangement, shape of trees, and shape of tree components with precision has been constrained by technological and logistical limitations and cost. Traditional methods of forest biometrics provide only partial measurements and are labor intensive. Active remote technologies such as LiDAR operated from airborne platforms provide only partial crown reconstructions. The use of terrestrial LiDAR is laborious, has portability limitations and high cost. In this work we capitalized on recent improvements in the capabilities and availability of small unmanned aerial vehicles (UAVs), light and inexpensive cameras, and developed an affordable method for obtaining precise and comprehensive 3D models of trees and small groups of trees. The method employs slow-moving UAVs that acquire images along predefined trajectories near and around targeted trees, and computer vision-based approaches that process the images to obtain detailed tree reconstructions. After we confirmed the potential of the methodology via simulation we evaluated several UAV platforms, strategies for image acquisition, and image processing algorithms. We present an original, step-by-step workflow which utilizes open source programs and original software. We anticipate that future development and applications of our method will improve our understanding of forest self-organization emerging from the competition among trees, and will lead to a refined generation of individual-tree-based forest models. PMID:26393926

3D Tree Dimensionality Assessment Using Photogrammetry and Small Unmanned Aerial Vehicles.

PubMed

Gatziolis, Demetrios; Lienard, Jean F; Vogs, Andre; Strigul, Nikolay S

2015-01-01

Detailed, precise, three-dimensional (3D) representations of individual trees are a prerequisite for an accurate assessment of tree competition, growth, and morphological plasticity. Until recently, our ability to measure the dimensionality, spatial arrangement, shape of trees, and shape of tree components with precision has been constrained by technological and logistical limitations and cost. Traditional methods of forest biometrics provide only partial measurements and are labor intensive. Active remote technologies such as LiDAR operated from airborne platforms provide only partial crown reconstructions. The use of terrestrial LiDAR is laborious, has portability limitations and high cost. In this work we capitalized on recent improvements in the capabilities and availability of small unmanned aerial vehicles (UAVs), light and inexpensive cameras, and developed an affordable method for obtaining precise and comprehensive 3D models of trees and small groups of trees. The method employs slow-moving UAVs that acquire images along predefined trajectories near and around targeted trees, and computer vision-based approaches that process the images to obtain detailed tree reconstructions. After we confirmed the potential of the methodology via simulation we evaluated several UAV platforms, strategies for image acquisition, and image processing algorithms. We present an original, step-by-step workflow which utilizes open source programs and original software. We anticipate that future development and applications of our method will improve our understanding of forest self-organization emerging from the competition among trees, and will lead to a refined generation of individual-tree-based forest models.

Prevention in dangerous industries: does safety certification prevent tree-faller injuries?

PubMed

McLeod, Christopher; Sarkany, Daniel; Davies, Hugh; Lyons, Kevin; Koehoorn, Mieke

2015-09-01

The aim of this study was to evaluate if safety certification reduces the risk of work injury among experienced manual tree-fallers. This study used a retrospective cohort study design. Experienced manual tree-fallers employed in the Canadian province of British Columbia (N=3251) between 2003-2008 were enumerated from a mandatory faller registry. Registry records with demographic and certification data were linked to workers' compensation claims for injury outcomes. Data were analyzed using discrete time survival analysis over a two-year period, centered on certification date with pre- and post-certification demarcated into four three-month periods. Models were adjusted for demographic, occupation/industry, previous injury, and seasonal/temporal effects. The relative risk (RR) of work injury during the post certification periods were elevated in comparison to the pre-certification reference period, but the 95% confidence intervals included "1" for all estimates by the end of follow-up, suggesting no statistically significant increased risk of injury. Results were consistent across different outcome measures of acute injury (ie, fracture or amputations) (N=186), musculoskeletal injury (ie, back strain) (N=137), and serious injury claims (ie, long duration, high cost and/or fatal) (N=155). Certification did not reduce the risk of work injury among experienced tree-fallers in the province of British Columbia. Non-statistically significant increases in the observed risk of work injury in the months immediately following certification may be attributable to an intervention effect or a methodological limitation related to a lack of individual-level, time-at-risk exposure data.

Spreading of multiple epidemics with cross immunization.

PubMed

Uekermann, Florian; Sneppen, Kim

2012-09-01

Pathogen-host relationships are the result of an ongoing coevolutionary race where the immune system of the host attempts to eliminate the pathogen, while the successful pathogen mutates to become invisible for the host's immune system. We here propose a minimal pathogen-host evolution model that takes into account cross immunization and allows for evolution of a spatially heterogeneous immune status of a population of hosts. With only the mutation rate as a determining parameter, the model allows us to produce an evolutionary tree of diseases which is highly branched, but hardly ever splits into separate long-lived trunks. Side branches remain short lived and seldom diverge to the extent of losing all cross immunizations.

Xylem transport models optimize effectiveness of systemic insecticide applications for controlling hemlock woolly adelgid (Adelges tsugae)

Treesearch

Chelcy R. Ford; Barbara C. Reynolds; James Vose

2010-01-01

The hemlock woolly adelgid (HWA, Adelges tsugae Annand) is causing widespread decline and mortality of eastern hemlock trees (Tsuga Canadensis (L.) Carr.). Stem injection of insecticide is widely used as a control measure, but its effectiveness depends on individual tree hydraulic characteristics. Recent work has shown that eastern...

Proceedings: second Lake States forest tree improvement conference

Treesearch

Lake States Forest Experiment Station

1955-01-01

I am firmly convinced that the Lake States Forest Tree Improvement Committee, and similar groups in other regions, can play an important role in encouraging and coordinating research and other activities in forest genetics. As this new field of work continues to expand, which it assuredly will, it will become of increasing importance to maintain close liaison among the...

The Americans with Disabilities Act: A Decision Tree for Social Services Administrators

ERIC Educational Resources Information Center

O'Brien, Gerald V.; Ellegood, Christina

2005-01-01

The 1990 Americans with Disabilities Act has had a profound influence on social workers and social services administrators in virtually all work settings. Because of the multiple elements of the act, however, assessing the validity of claims can be a somewhat arduous and complicated task. This article provides a "decision tree" for…

Silvical Characteristics of Yellow-Poplar

Treesearch

David F. Olson

1969-01-01

Yellow-poplar (Liriorlentlron tulipifera L.) is also commonly known as tulip poplar, tulip tree, white-poplar, whitewood, and "poplar" (60). It gets its name from the tulip-like flowers which it bears in the late spring. Because of the excellent form and rapid growth of the tree, plus the fine working qualities of the wood, yellow-poplar is one of the most...

The role of genetics and tree improvement in southern forest productivity

Treesearch

Ronald C. Schmidtling; T.L. Robison; S.E. McKeand; R.J. Rousseau; H.L. Allen; B. Goldfarb

2004-01-01

Because of space limitations, a thorough discussion of the rich history of tree improvement in the Southeastern United States cannot be totally accomplished in this forum. However, a synopsis of key program highlights and the people who forged and directed these programs is presented, together with a discussion of current and future work. This discussion covers...

The atopic dog as a model of peanut and tree nut food allergy.

PubMed

Teuber, Suzanne S; Del Val, Gregorio; Morigasaki, Susumu; Jung, Hye Rim; Eisele, Pamela H; Frick, Oscar L; Buchanan, Bob B

2002-12-01

Animal models are needed that mimic human IgE-mediated peanut and tree nut allergy. Atopic dogs have been previously used in a model of food allergy to cow's milk, beef, wheat, and soy, with the demonstration of specific IgE production and positive oral challenges similar to those seen in human subjects. We sought to sensitize dogs to peanut, walnut, and Brazil nut and to assess whether sensitization is accompanied by clinical reactions and whether there is cross-reactivity among the different preparations. Eleven dogs were sensitized subcutaneously by using an established protocol with 1 microg each of peanut, English walnut, or Brazil nut protein extracts in alum first at birth and then after modified live virus vaccinations at 3, 7, and 11 weeks of age. The dogs were sensitized to other allergens, including soy and either wheat or barley. Intradermal skin tests, IgE immunoblotting to nut proteins, and oral challenges were performed with ground nut preparations. At 6 months of age, the dogs' intradermal skin test responses were positive to the nut extracts. IgE immunoblotting to peanut, walnut, and Brazil nut showed strong recognition of proteins in the aqueous preparations. Each of the 4 peanut- and the 3 Brazil nut-sensitized dogs and 3 of the 4 walnut-sensitized dogs reacted on oral challenge with the corresponding primary immunogen at age 2 years. None of the peanut-sensitized dogs reacted clinically with walnut or Brazil nut challenges. One of the walnut-sensitized dogs had delayed (overnight) vomiting to Brazil nut. On the basis of measurements of the mean amount of allergen eliciting a skin test response in dogs, the hierarchy of reactivity by skin testing is similar to the clinical experience in human subjects (peanut > tree nuts > wheat > soy > barley). Cross-reactivity, which was not apparent between soy and peanut or tree nuts or between peanut and tree nuts, was slight between walnut and Brazil nut. The results give further support to the dog as a model of human food allergy.

Fire frequency in the Interior Columbia River Basin: Building regional models from fire history data

USGS Publications Warehouse

McKenzie, D.; Peterson, D.L.; Agee, James K.

2000-01-01

Fire frequency affects vegetation composition and successional pathways; thus it is essential to understand fire regimes in order to manage natural resources at broad spatial scales. Fire history data are lacking for many regions for which fire management decisions are being made, so models are needed to estimate past fire frequency where local data are not yet available. We developed multiple regression models and tree-based (classification and regression tree, or CART) models to predict fire return intervals across the interior Columbia River basin at 1-km resolution, using georeferenced fire history, potential vegetation, cover type, and precipitation databases. The models combined semiqualitative methods and rigorous statistics. The fire history data are of uneven quality; some estimates are based on only one tree, and many are not cross-dated. Therefore, we weighted the models based on data quality and performed a sensitivity analysis of the effects on the models of estimation errors that are due to lack of cross-dating. The regression models predict fire return intervals from 1 to 375 yr for forested areas, whereas the tree-based models predict a range of 8 to 150 yr. Both types of models predict latitudinal and elevational gradients of increasing fire return intervals. Examination of regional-scale output suggests that, although the tree-based models explain more of the variation in the original data, the regression models are less likely to produce extrapolation errors. Thus, the models serve complementary purposes in elucidating the relationships among fire frequency, the predictor variables, and spatial scale. The models can provide local managers with quantitative information and provide data to initialize coarse-scale fire-effects models, although predictions for individual sites should be treated with caution because of the varying quality and uneven spatial coverage of the fire history database. The models also demonstrate the integration of qualitative and quantitative methods when requisite data for fully quantitative models are unavailable. They can be tested by comparing new, independent fire history reconstructions against their predictions and can be continually updated, as better fire history data become available.

Elevated air humidity affects hydraulic traits and tree size but not biomass allocation in young silver birches (Betula pendula)

PubMed Central

Sellin, Arne; Rosenvald, Katrin; Õunapuu-Pikas, Eele; Tullus, Arvo; Ostonen, Ivika; Lõhmus, Krista

2015-01-01

As changes in air temperature, precipitation, and air humidity are expected in the coming decades, studies on the impact of these environmental shifts on plant growth and functioning are of major importance. Greatly understudied aspects of climate change include consequences of increasing air humidity on forest ecosystems, predicted for high latitudes. The main objective of this study was to find a link between hydraulic acclimation and shifts in trees’ resource allocation in silver birch (Betula pendula Roth) in response to elevated air relative humidity (RH). A second question was whether the changes in hydraulic architecture depend on tree size. Two years of application of increased RH decreased the biomass accumulation in birch saplings, but the biomass partitioning among aboveground parts (leaves, branches, and stems) remained unaffected. Increased stem Huber values (xylem cross-sectional area to leaf area ratio) observed in trees under elevated RH did not entail changes in the ratio of non-photosynthetic to photosynthetic tissues. The reduction of stem–wood density is attributable to diminished mechanical load imposed on the stem, since humidified trees had relatively shorter crowns. Growing under higher RH caused hydraulic conductance of the root system (KR) to increase, while KR (expressed per unit leaf area) decreased and leaf hydraulic conductance increased with tree size. Saplings of silver birch acclimate to increasing air humidity by adjusting plant morphology (live crown length, slenderness, specific leaf area, and fine-root traits) and wood density rather than biomass distribution among aboveground organs. The treatment had a significant effect on several hydraulic properties of the trees, while the shifts were largely associated with changes in tree size but not in biomass allocation. PMID:26528318

Effects of inbreeding on coastal Douglas fir growth and yield in operational plantations: a model-based approach.

PubMed

Wang, Tongli; Aitken, Sally N; Woods, Jack H; Polsson, Ken; Magnussen, Steen

2004-04-01

In advanced generation seed orchards, tradeoffs exist between genetic gain obtained by selecting the best related individuals for seed orchard populations, and potential losses due to subsequent inbreeding between these individuals. Although inbreeding depression for growth rate is strong in most forest tree species at the individual tree level, the effect of a small proportion of inbreds in seed lots on final stand yield may be less important. The effects of inbreeding on wood production of mature stands cannot be assessed empirically in the short term, thus such effects were simulated for coastal Douglas fir [ Pseudotsuga menziesii var. menziesii (Mirb.) Franco] using an individual-tree growth and yield model TASS (Tree and Stand Simulator). The simulations were based on seed set, nursery culling rates, and 10-year-old field test performance for trees resulting from crosses between unrelated individuals and for inbred trees produced through mating between half-sibs, full-sibs, parents and offspring and self-pollination. Results indicate that inclusion of a small proportion of related clones in seed orchards will have relatively low impacts on stand yields due to low probability of related individuals mating, lower probability of producing acceptable seedlings from related matings than from unrelated matings, and a greater probability of competition-induced mortality for slower growing inbred individuals than for outcrossed trees. Thus, competition reduces the losses expected due to inbreeding depression at harvest, particularly on better sites with higher planting densities and longer rotations. Slightly higher breeding values for related clones than unrelated clones would offset or exceed the effects of inbreeding resulting from related matings. Concerns regarding the maintenance of genetic diversity are more likely to limit inclusion of related clones in orchards than inbreeding depression for final stand yield.

Combining airborne laser scanning and Landsat data for statistical modeling of soil carbon and tree biomass in Tanzanian Miombo woodlands.

PubMed

Egberth, Mikael; Nyberg, Gert; Næsset, Erik; Gobakken, Terje; Mauya, Ernest; Malimbwi, Rogers; Katani, Josiah; Chamuya, Nurudin; Bulenga, George; Olsson, Håkan

2017-12-01

Soil carbon and biomass depletion can be used to identify and quantify degraded soils, and by using remote sensing, there is potential to map soil conditions over large areas. Landsat 8 Operational Land Imager satellite data and airborne laser scanning data were evaluated separately and in combination for modeling soil organic carbon, above ground tree biomass and below ground tree biomass. The test site is situated in the Liwale district in southeastern Tanzania and is dominated by Miombo woodlands. Tree data from 15 m radius field-surveyed plots and samples of soil carbon down to a depth of 30 cm were used as reference data for tree biomass and soil carbon estimations. Cross-validated plot level error (RMSE) for predicting soil organic carbon was 28% using only Landsat 8, 26% using laser only, and 23% for the combination of the two. The plot level error for above ground tree biomass was 66% when using only Landsat 8, 50% for laser and 49% for the combination of Landsat 8 and laser data. Results for below ground tree biomass were similar to above ground biomass. Additionally it was found that an early dry season satellite image was preferable for modelling biomass while images from later in the dry season were better for modelling soil carbon. The results show that laser data is superior to Landsat 8 when predicting both soil carbon and biomass above and below ground in landscapes dominated by Miombo woodlands. Furthermore, the combination of laser data and Landsat data were marginally better than using laser data only.

STBase: one million species trees for comparative biology.

PubMed

McMahon, Michelle M; Deepak, Akshay; Fernández-Baca, David; Boss, Darren; Sanderson, Michael J

2015-01-01

Comprehensively sampled phylogenetic trees provide the most compelling foundations for strong inferences in comparative evolutionary biology. Mismatches are common, however, between the taxa for which comparative data are available and the taxa sampled by published phylogenetic analyses. Moreover, many published phylogenies are gene trees, which cannot always be adapted immediately for species level comparisons because of discordance, gene duplication, and other confounding biological processes. A new database, STBase, lets comparative biologists quickly retrieve species level phylogenetic hypotheses in response to a query list of species names. The database consists of 1 million single- and multi-locus data sets, each with a confidence set of 1000 putative species trees, computed from GenBank sequence data for 413,000 eukaryotic taxa. Two bodies of theoretical work are leveraged to aid in the assembly of multi-locus concatenated data sets for species tree construction. First, multiply labeled gene trees are pruned to conflict-free singly-labeled species-level trees that can be combined between loci. Second, impacts of missing data in multi-locus data sets are ameliorated by assembling only decisive data sets. Data sets overlapping with the user's query are ranked using a scheme that depends on user-provided weights for tree quality and for taxonomic overlap of the tree with the query. Retrieval times are independent of the size of the database, typically a few seconds. Tree quality is assessed by a real-time evaluation of bootstrap support on just the overlapping subtree. Associated sequence alignments, tree files and metadata can be downloaded for subsequent analysis. STBase provides a tool for comparative biologists interested in exploiting the most relevant sequence data available for the taxa of interest. It may also serve as a prototype for future species tree oriented databases and as a resource for assembly of larger species phylogenies from precomputed trees.

Accelerating the domestication of forest trees in a changing world.

PubMed

Harfouche, Antoine; Meilan, Richard; Kirst, Matias; Morgante, Michele; Boerjan, Wout; Sabatti, Maurizio; Scarascia Mugnozza, Giuseppe

2012-02-01

In light of impending water and arable land shortages, population growth and climate change, it is more important than ever to examine how forest tree domestication can be accelerated to sustainably meet future demands for wood, biomass, paper, fuel and biomaterials. Because of long breeding cycles, tree domestication cannot be rapidly achieved through traditional genetic improvement methods alone. Integrating modern genetic and genomic techniques with conventional breeding will expedite tree domestication. Breeders will only embrace these technologies if they are cost-effective and readily accessible, and forest landowners will only adopt end-products that meet with regulatory approval and public acceptance. All parties involved must work together to achieve these objectives for the benefit of society. Copyright © 2011 Elsevier Ltd. All rights reserved.

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

NASA Astrophysics Data System (ADS)

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: 2011, 35 cm, 7.0 cm/year; 1973, 77 cm, 1.8 cm/year; 1962, 140 cm, 2.6 cm/year; 1960, 123 cm, 2.2 cm/year; and 1862, 112 cm, 0.7 cm/year. These sedimentation rates indicate that the cumulative sedimentation decreases as a power law with increasing tree age.

Pathogen-Induced Leaf Chlorosis: Products of Chlorophyll Breakdown Found in Degreened Leaves of Phytoplasma-Infected Apple (Malus × domestica Borkh.) and Apricot (Prunus armeniaca L.) Trees Relate to the Pheophorbide a Oxygenase/Phyllobilin Pathway.

PubMed

Mittelberger, Cecilia; Yalcinkaya, Hacer; Pichler, Christa; Gasser, Johanna; Scherzer, Gerhard; Erhart, Theresia; Schumacher, Sandra; Holzner, Barbara; Janik, Katrin; Robatscher, Peter; Müller, Thomas; Kräutler, Bernhard; Oberhuber, Michael

2017-04-05

Phytoplasmoses such as apple proliferation (AP) and European stone fruit yellows (ESFY) cause severe economic losses in fruit production. A common symptom of both phytoplasma diseases is early yellowing or leaf chlorosis. Even though chlorosis is a well-studied symptom of biotic and abiotic stresses, its biochemical pathways are hardly known. In particular, in this context, a potential role of the senescence-related pheophorbide a oxygenase/phyllobilin (PaO/PB) pathway is elusive, which degrades chlorophyll (Chl) to phyllobilins (PBs), most notably to colorless nonfluorescent Chl catabolites (NCCs). In this work, we identified the Chl catabolites in extracts of healthy senescent apple and apricot leaves. In extracts of apple tree leaves, a total of 12 Chl catabolites were detected, and in extracts of leaves of the apricot tree 16 Chl catabolites were found. The seven major NCC fractions in the leaves of both fruit tree species were identical and displayed known structures. All of the major Chl catabolites were also found in leaf extracts from AP- or ESFY-infected trees, providing the first evidence that the PaO/PB pathway is relevant also for pathogen-induced chlorosis. This work supports the hypothesis that Chl breakdown in senescence and phytoplasma infection proceeds via a common pathway in some members of the Rosaceae family.

Dating floodplain sediments using tree-ring response to burial

USGS Publications Warehouse

Friedman, J.M.; Vincent, K.R.; Shafroth, P.B.

2005-01-01

Floodplain sediments can be dated precisely based on the change in anatomy of tree rings upon burial. When a stem of tamarisk (Tamarix ramosissima) or sandbar willow (Salix exigua) is buried, subsequent annual rings in the buried section resemble the rings of roots: rings become narrower, vessels within the rings become larger, and transitions between rings become less distinct. We combined observations of these changes with tree-ring counts to determine the year of deposition of sedimentary beds exposed in a 150-m-long trench across the floodplain of the Rio Puerco, a rapidly filling arroyo in New Mexico. This method reliably dated most beds thicker than about 30 cm to within a year of deposition. Floodplain aggradation rates varied dramatically through time and space. Sediment deposition was mostly limited to brief overbank flows occurring every few years. The most rapid deposition occurred on channel-margin levees, which migrated laterally during channel narrowing. At the decadal timescale, the cross-section-average sediment deposition rate was steady, but there was a shift in the spatial pattern of deposition in the 1980s. From 1936 to 1986, sediment deposition occurred by channel narrowing, with little change in elevation of the thalweg. After 1986 sediment deposition occurred by vertical aggradation. From 1936 to 2000 about 27 per cent of the arroyo cross-section filled with sediment. The rate of filling from 1962 to 2000 was 0-8 vertical m/decade or 85 m2/decade. Published in 2005 by John Wiley & Sons, Ltd.

Dating floodplain sediments using tree-ring response to burial

USGS Publications Warehouse

Friedman, J.M.; Vincent, K.R.; Shafroth, P.B.

2005-01-01

Floodplain sediments can be dated precisely based on the change in anatomy of tree rings upon burial. When a stem of tamarisk (Tamarix ramosissima) or sandbar willow (Salix exigua) is buried, subsequent annual rings in the buried section resemble the rings of roots: rings become narrower, vessels within the rings become larger, and transitions between rings become less distinct. We combined observations of these changes with tree-ring counts to determine the year of deposition of sedimentary beds exposed in a 150-m-long trench across the floodplain of the Rio Puerco, a rapidly filling arroyo in New Mexico. This method reliably dated most beds thicker than about 30 cm to within a year of deposition. Floodplain aggradation rates varied dramatically through time and space. Sediment deposition was mostly limited to brief overbank flows occurring every few years. The most rapid deposition occurred on channel-margin levees, which migrated laterally during channel narrowing. At the decadal timescale, the cross-section-average sediment deposition rate was steady, but there was a shift in the spatial pattern of deposition in the 1980s. From 1936 to 1986, sediment deposition occurred by channel narrowing, with little change in elevation of the thalweg. After 1986 sediment deposition occurred by vertical aggradation. From 1936 to 2000 about 27 per cent of the arroyo cross-section filled with sediment. The rate of filling from 1962 to 2000 was 0·8 vertical m/decade or 85 m2/decade.

Allergenic potential of novel foods.

PubMed

Meredith, Clive

2005-11-01

Concerns have been expressed that the introduction of novel foods into the diet might lead to the development of new food allergies in consumers. Novel foods can be conveniently divided into GM and non-GM categories. Decision-tree approaches (e.g. International Life Sciences Institute-International Food Biotechnology Council and WHO/FAO) to assess the allergenic potential of GM foods were developed following the discovery, during product development, of the allergenic potential of GM soyabean expressing a gene encoding a storage protein from Brazil nut (Bertolletia excelsa). Within these decision trees considerations include: the source of the transgene; amino acid homology with known allergens; cross-reactivity with IgE from food-allergic individuals; resistance to proteolysis; prediction using animal models of food allergy. Such decision trees are under constant review as new knowledge and improved models emerge, but they provide a useful framework for the assessment of the allergenic potential of GM foods. For novel non-GM foods the assessment of allergenic potential is more subjective; some foods or food ingredients will need no assessment other than a robust protein assay to demonstrate the absence of protein. Where protein is present in the novel non-GM food, hazard and risk assessments need to be made in terms of the quantity of protein that might be consumed, the identity of individual protein components and their relationships to known food allergens. Where necessary, this assessment would extend to serum screening for potential cross-reactivities, skin-prick tests in previously-sensitised individuals and double-blind placebo-controlled food challenges.

EVALUATION OF TWO METHODS OF THERMAL WEED CONTROL IN FRUIT TREE ORCHARDS, PESTICIDE SPECIAL STUDY, COLORADO STATE UNIVERSITY

EPA Science Inventory

Research Objectives: 1) Compare the efficiency of two different types of thermal flamers: a direct flamer (Red Dragon, Inc., LaCrosse, Kansas) and a prototype infrared weed flamer (Sunburst, Inc., Eugene Oregon) in controlling weed populations in an apple orchard. 2) Determine ...

Self Addressed Questions and Filled Pauses: A Cross-Linguistic Investigation

ERIC Educational Resources Information Center

Tian, Ye; Maruyama, Takehiko; Ginzburg, Jonathan

2017-01-01

There is an ongoing debate whether phenomena of disfluency (such as filled pauses) are produced communicatively. Clark and Fox Tree ("Cognition" 84(1):73-111, 2002) propose that filled pauses are words, and that different forms signal different lengths of delay. This paper evaluates this Filler-As-Words hypothesis by analyzing the…

Whitebark pine diameter growth response to removal of competition

Treesearch

Robert E. Keane; Kathy L. Gray; Laura J. Dickinson

2007-01-01

Silvicultural cutting treatments may be needed to restore whitebark pine (Pinus albicaulis) forests, but little is known of the response of this species to removal of competition through prescribed burning or silvicultural cuttings. We analyzed stem cross-sections from 48 whitebark pine trees in Montana around which most of the competing vegetation...

Prevalence and Determinants of Preterm Birth in Tehran, Iran: A Comparison between Logistic Regression and Decision Tree Methods.

PubMed

Amini, Payam; Maroufizadeh, Saman; Samani, Reza Omani; Hamidi, Omid; Sepidarkish, Mahdi

2017-06-01

Preterm birth (PTB) is a leading cause of neonatal death and the second biggest cause of death in children under five years of age. The objective of this study was to determine the prevalence of PTB and its associated factors using logistic regression and decision tree classification methods. This cross-sectional study was conducted on 4,415 pregnant women in Tehran, Iran, from July 6-21, 2015. Data were collected by a researcher-developed questionnaire through interviews with mothers and review of their medical records. To evaluate the accuracy of the logistic regression and decision tree methods, several indices such as sensitivity, specificity, and the area under the curve were used. The PTB rate was 5.5% in this study. The logistic regression outperformed the decision tree for the classification of PTB based on risk factors. Logistic regression showed that multiple pregnancies, mothers with preeclampsia, and those who conceived with assisted reproductive technology had an increased risk for PTB ( p < 0.05). Identifying and training mothers at risk as well as improving prenatal care may reduce the PTB rate. We also recommend that statisticians utilize the logistic regression model for the classification of risk groups for PTB.

AIR Louisville: Addressing Asthma With Technology, Crowdsourcing, Cross-Sector Collaboration, And Policy.

PubMed

Barrett, Meredith; Combs, Veronica; Su, Jason G; Henderson, Kelly; Tuffli, Michael

2018-04-01

Cross-sector partnerships benefit public health by leveraging ideas, resources, and expertise from a wide range of partners. In this study we documented the process and impact of AIR Louisville (a collaboration forged among the Louisville Metro Government, a nonprofit institute, and a technology company) in successfully tackling a complex public health challenge: asthma. We enrolled residents of Louisville, Kentucky, with asthma and used electronic inhaler sensors to monitor where and when they used medication. We found that the use of the digital health platform achieved positive clinical outcomes, including a 78 percent reduction in rescue inhaler use and a 48 percent improvement in symptom-free days. Moreover, the crowdsourced real-world data on inhaler use, combined with environmental data, led to policy recommendations including enhancing tree canopy, tree removal mitigation, zoning for air pollution emission buffers, recommended truck routes, and developing a community asthma notification system. AIR Louisville represents a model that can be replicated to address many public health challenges by simultaneously guiding individual, clinical, and policy decisions.

Structural changes in the minimal spanning tree and the hierarchical network in the Korean stock market around the global financial crisis

NASA Astrophysics Data System (ADS)

Nobi, Ashadun; Maeng, Seong Eun; Ha, Gyeong Gyun; Lee, Jae Woo

2015-04-01

This paper considers stock prices in the Korean stock market during the 2008 global financial crisis by focusing on three time periods: before, during, and after the crisis. Complex networks are extracted from cross-correlation coefficients between the normalized logarithmic return of the stock price time series of firms. The minimal spanning trees (MSTs) and the hierarchical network (HN) are generated from cross-correlation coefficients. Before and after the crisis, securities firms are located at the center of the MST. During the crisis, however, the center of the MST changes to a firm in heavy industry and construction. During the crisis, the MST shrinks in comparison to that before and that after the crisis. This topological change in the MST during the crisis reflects a distinct effect of the global financial crisis. The cophenetic correlation coefficient increases during the crisis, indicating an increase in the hierarchical structure during in this period. When crisis hits the market, firms behave synchronously, and their correlations are higher than those during a normal period.

Assessing Conifer Ray Parenchyma for Ecological Studies: Pitfalls and Guidelines.

PubMed

von Arx, Georg; Arzac, Alberto; Olano, José M; Fonti, Patrick

2015-01-01

Ray parenchyma is an essential tissue for tree functioning and survival. This living tissue plays a major role for storage and transport of water, nutrients, and non-structural carbohydrates (NSC), thus regulating xylem hydraulics and growth. However, despite the importance of rays for tree carbon and water relations, methodological challenges hamper knowledge about ray intra- and inter-tree variability and its ecological meaning. In this study we provide a methodological toolbox for soundly quantifying spatial and temporal variability of different ray features. Anatomical ray features were surveyed in different cutting planes (cross-sectional, tangential, and radial) using quantitative image analysis on stem-wood micro-sections sampled from 41 mature Scots pines (Pinus sylvestris). The percentage of ray surface (PERPAR), a proxy for ray volume, was compared among cutting planes and between early- and latewood to assess measurement-induced variability. Different tangential ray metrics were correlated to assess their similarities. The accuracy of cross-sectional and tangential measurements for PERPAR estimates as a function of number of samples and the measured wood surface was assessed using bootstrapping statistical technique. Tangential sections offered the best 3D insight of ray integration into the xylem and provided the most accurate estimates of PERPAR, with 10 samples of 4 mm(2) showing an estimate within ±6.0% of the true mean PERPAR (relative 95% confidence interval, CI95), and 20 samples of 4 mm(2) showing a CI95 of ±4.3%. Cross-sections were most efficient for establishment of time series, and facilitated comparisons with other widely used xylem anatomical features. Earlywood had significantly lower PERPAR (5.77 vs. 6.18%) and marginally fewer initiating rays than latewood. In comparison to tangential sections, PERPAR was systematically overestimated (6.50 vs. 4.92%) and required approximately twice the sample area for similar accuracy. Radial cuttings provided the least accurate PERPAR estimates. This evaluation of ray parenchyma in conifers and the presented guidelines regarding data accuracy as a function of measured wood surface and number of samples represent an important methodological reference for ray quantification, which will ultimately improve the understanding of the fundamental role of ray parenchyma tissue for the performance and survival of trees growing in stressed environments.

Assessing Conifer Ray Parenchyma for Ecological Studies: Pitfalls and Guidelines

PubMed Central

von Arx, Georg; Arzac, Alberto; Olano, José M.; Fonti, Patrick

2015-01-01

Ray parenchyma is an essential tissue for tree functioning and survival. This living tissue plays a major role for storage and transport of water, nutrients, and non-structural carbohydrates (NSC), thus regulating xylem hydraulics and growth. However, despite the importance of rays for tree carbon and water relations, methodological challenges hamper knowledge about ray intra- and inter-tree variability and its ecological meaning. In this study we provide a methodological toolbox for soundly quantifying spatial and temporal variability of different ray features. Anatomical ray features were surveyed in different cutting planes (cross-sectional, tangential, and radial) using quantitative image analysis on stem-wood micro-sections sampled from 41 mature Scots pines (Pinus sylvestris). The percentage of ray surface (PERPAR), a proxy for ray volume, was compared among cutting planes and between early- and latewood to assess measurement-induced variability. Different tangential ray metrics were correlated to assess their similarities. The accuracy of cross-sectional and tangential measurements for PERPAR estimates as a function of number of samples and the measured wood surface was assessed using bootstrapping statistical technique. Tangential sections offered the best 3D insight of ray integration into the xylem and provided the most accurate estimates of PERPAR, with 10 samples of 4 mm2 showing an estimate within ±6.0% of the true mean PERPAR (relative 95% confidence interval, CI95), and 20 samples of 4 mm2 showing a CI95 of ±4.3%. Cross-sections were most efficient for establishment of time series, and facilitated comparisons with other widely used xylem anatomical features. Earlywood had significantly lower PERPAR (5.77 vs. 6.18%) and marginally fewer initiating rays than latewood. In comparison to tangential sections, PERPAR was systematically overestimated (6.50 vs. 4.92%) and required approximately twice the sample area for similar accuracy. Radial cuttings provided the least accurate PERPAR estimates. This evaluation of ray parenchyma in conifers and the presented guidelines regarding data accuracy as a function of measured wood surface and number of samples represent an important methodological reference for ray quantification, which will ultimately improve the understanding of the fundamental role of ray parenchyma tissue for the performance and survival of trees growing in stressed environments. PMID:26635842

From Loops to Trees By-passing Feynman's Theorem

DOE Office of Scientific and Technical Information (OSTI.GOV)

Catani, Stefano; Gleisberg, Tanju; Krauss, Frank

2008-04-22

We derive a duality relation between one-loop integrals and phase-space integrals emerging from them through single cuts. The duality relation is realized by a modification of the customary + i0 prescription of the Feynman propagators. The new prescription regularizing the propagators, which we write in a Lorentz covariant form, compensates for the absence of multiple cut contributions that appear in the Feynman Tree Theorem. The duality relation can be applied to generic one-loop quantities in any relativistic, local and unitary field theories. It is suitable for applications to the analytical calculation of one-loop scattering amplitudes, and to the numerical evaluationmore » of cross-sections at next-to-leading order.« less

Explaining the dependence of climatic response of tree radial growth on permafrost

NASA Astrophysics Data System (ADS)

Bryukhanova, Marina; Benkova, Anna; von Arx, Georg; Fonti, Patrick; Simanko, Valentina; Kirdyanov, Alexander; Shashkin, Alexander

2015-04-01

In northern regions of Siberia it is infrequent to have long-term observations of the variability of soil features, phenological data, duration of the growing season, which can be used to infer the influence of the environment on tree growth and productivity. The best way to understand tree-growth and tree responses to environmental changes is to make use of mechanistic models, allowing to combine already available experiment/field data with other parameters based on biological principles of tree growth. The goal of our study is to estimate which tree species (deciduous, conifer deciduous or conifer evergreen) is more plastic under possible climate changes in permafrost zone. The studied object is located in the northern part of central Siberia, Russia (64°N, 100°E). The study plot was selected within a post-fire succession and representatives for 100 years old even aged mixed forest of Larix gmelinii (Rupr.) Rupr. and Betula pubescens Ehrh. with few exemplars of Spruce (Picea obovata Ledeb.). To understand physiological response of larch, birch and spruce trees to climatic changes the ecological-physiological process-based model of tree photosynthesis (Benkova and Shashkin 2003) was applied. Multiparametric tree-ring chronologies were analyzed and correlated with climatic parameters over the last 77 years. This work is supported by the Ministry of Education and Science of the Russian Federation (Grant from the President of RF for Young Scientists MK-1589.2014.4).

jsPhyloSVG: a javascript library for visualizing interactive and vector-based phylogenetic trees on the web.

PubMed

Smits, Samuel A; Ouverney, Cleber C

2010-08-18

Many software packages have been developed to address the need for generating phylogenetic trees intended for print. With an increased use of the web to disseminate scientific literature, there is a need for phylogenetic trees to be viewable across many types of devices and feature some of the interactive elements that are integral to the browsing experience. We propose a novel approach for publishing interactive phylogenetic trees. We present a javascript library, jsPhyloSVG, which facilitates constructing interactive phylogenetic trees from raw Newick or phyloXML formats directly within the browser in Scalable Vector Graphics (SVG) format. It is designed to work across all major browsers and renders an alternative format for those browsers that do not support SVG. The library provides tools for building rectangular and circular phylograms with integrated charting. Interactive features may be integrated and made to respond to events such as clicks on any element of the tree, including labels. jsPhyloSVG is an open-source solution for rendering dynamic phylogenetic trees. It is capable of generating complex and interactive phylogenetic trees across all major browsers without the need for plugins. It is novel in supporting the ability to interpret the tree inference formats directly, exposing the underlying markup to data-mining services. The library source code, extensive documentation and live examples are freely accessible at www.jsphylosvg.com.

Clinical and immunobiochemical characterization of airborne Delonix regia (Gulmohar tree) pollen and cross-reactivity studies with Peltophorum pterocarpum pollen: 2 dominant avenue trees from eastern India.

PubMed

Mandal, Jyotshna; Manna, Prasenjit; Chakraborty, Pampa; Roy, Indrani; Gupta-Bhattacharya, Swati

2009-12-01

Delonix regia and Peltophorum pterocarpum pollen are important aeroallergens for type 1 hypersensitivity in the tropics. The IgE-binding proteins of D regia and their cross-allergenity with P pterocarpum pollen have not been evaluated. To isolate and characterize the IgE-binding proteins of D regia pollen for the first time and to investigate the cross-allergenity with P pterocarpum pollen belonging to the same family (Leguminosae). Allergenic activities were determined by in vivo and in vitro analyses. Pollen extract was fractionated by a combination of 2 columns (diethyl amino ethyl Sephadex and Sephacryl S-200). Protein components were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, periodic acid-Schiff staining, and immunoblotting. In vitro inhibition tests were performed to evaluate the cross-reactivity. The skin prick test results of the patients with respiratory allergies in Calcutta, India, showed 31.1% positivity with D regia pollen. Nine IgE-reactive protein components were found in the crude extract. An optimum IgE-reactive fraction was resolved into 4 subfractions. Subfraction A, which showed maximum IgE reactivity, contained 2 (96- and 66-kDa) IgE-reactive protein components. The 66-kDa component was found to be glycoprotein. Remarkable cross-reactivity between D regia and P pterocarpum pollen was found on IgE enzyme-linked immunosorbent assay inhibition and dot blotting. Shared IgE-binding components (66, 56, 32, 28, 25, and 23 kDa) were observed between D regia and P pterocarpum pollen extracts, whereas the 96- and 43-kDa components were specific to D regia. The purification of the IgE-binding proteins and the identification of the shared/cross-reactive proteins in these taxonomically related pollen members should be helpful for the diagnosis and therapy of patients susceptible to these pollens.

Health monitoring of an ancient tree using ground penetrating radar - investigation of the tree root system and soil interaction

NASA Astrophysics Data System (ADS)

Alani, Amir M.; Bianchini Ciampoli, Luca; Tosti, Fabio; Giulia Brancadoro, Maria; Pirrone, Daniele; Benedetto, Andrea

2017-04-01

The sensibility towards environmental issues along with the attention on preserving natural heritage, especially ancient trees and rare plants, has greatly increased, and the management and the control of the forestall heritage and the floral system has become accordingly a high-priority objective to achieve. One of the main factors of tree decay which originally gained public attention is the presence of unknown pathogens carried along by the wind, which can lead to epidemic phenomena and often to a quick death of entire forests. In such an emergency situation, two main approaches can be followed, namely, i) active measures (i.e., the avoidance of any contact between the pathogenic spores and the trees by using bio-security measures) and ii) passive measures (i.e., the application of policies for the control and the management of the forestall heritage aimed at identifying the early-stage symptoms of the disease). Since the latest approach is based on the monitoring of living trees, invasive methods of health assessment like cutting off branches or incremental coring are increasingly discouraged, and non-destructive evaluation proves to be the only option to undertake. The applications of non-destructive testing (NDT) techniques in forestry sciences are often self-standing and not integrated with one another. This is often due to a lack of knowledge from the NDT users towards the physics and the bio-chemical processes which mainly govern the life cycle of trees and plants. Such an issue is emphasized by the evident complexity of the plant and trunk systems themselves. Notwithstanding this, the ground-penetrating radar (GPR) technique has proved to be one of the most effective, due to its high versatility, rapidity in collecting data and the provision of reliable results at relatively limited costs. The use of GPR can provide invaluable information about the effective tree trunk assessment and appraisals, tree roots mapping, soil interaction with tree and plants. In addition, the use of simulation can be a supporting tool for the development of a clear understanding of the decay processes in trees. In this study, a demonstration of the GPR potential in the health monitoring of an ancient tree has been given. The main objectives of the research were to provide an effective mapping of the tree roots as well as reliable simulation scenarios representing a variety of possible internal defects in terms of shape and formation. To these purposes, the soil around a 100-years old fir tree, with a trunk circumference of 3.40 m and an average radius of 0.55 m, was investigated. Nine radial scans, 0.30 m spaced each to one another, were carried out all around the tree circumference starting from 0.50 m the outer surface of the bark. A ground-coupled multi-frequency GPR system equipped with 600 MHz and 1600 MHz central frequency antennas was used for testing purposes. In order to reach the maximum penetration depth of the root system, only the 600 MHz frequency was considered for data processing purposes. After the application of a dedicated signal processing scheme, it was possible to produce a tomographic map of amplitudes covering a swept circle with an outer radius of 3.45 m and an inner radius of 1.05 m up to a maximum depth of 1.56 m. By using a set of specially developed algorithms it was possible to extract signal amplitude information reliably related to the position of the tree roots under the soil. In addition to the above objective, finite-difference time-domain (FDTD) simulations of the electromagnetic field propagation through the cross section of a trunk were carried out. To this purpose, the numerical simulator package gprMax 2D was used. The freeware tool E2GPR aided the design of the gprMax models and their distributed execution on multicore machines. The dimensions and the dielectric properties of the simulated trunk were consistent with the investigated fir tree (actual data collected). Furthermore, a variety of defects representing cavities created due to decay was simulated. The results from the simulations demonstrated significant potential for the interpretation of complex decay phenomena within the trunk as well as for mapping and comparison of the actual field data. Acknowledgements The authors acknowledge Mr. Spartaco Cera, from Roma Tre University, for his invaluable help during the field work. We also acknowledge the COST Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar" for providing networking and discussion opportunities throughout its activity and operation as well as facilitating prospect for publishing research outputs.

Principal component analysis and the locus of the Fréchet mean in the space of phylogenetic trees.

PubMed

Nye, Tom M W; Tang, Xiaoxian; Weyenberg, Grady; Yoshida, Ruriko

2017-12-01

Evolutionary relationships are represented by phylogenetic trees, and a phylogenetic analysis of gene sequences typically produces a collection of these trees, one for each gene in the analysis. Analysis of samples of trees is difficult due to the multi-dimensionality of the space of possible trees. In Euclidean spaces, principal component analysis is a popular method of reducing high-dimensional data to a low-dimensional representation that preserves much of the sample's structure. However, the space of all phylogenetic trees on a fixed set of species does not form a Euclidean vector space, and methods adapted to tree space are needed. Previous work introduced the notion of a principal geodesic in this space, analogous to the first principal component. Here we propose a geometric object for tree space similar to the [Formula: see text]th principal component in Euclidean space: the locus of the weighted Fréchet mean of [Formula: see text] vertex trees when the weights vary over the [Formula: see text]-simplex. We establish some basic properties of these objects, in particular showing that they have dimension [Formula: see text], and propose algorithms for projection onto these surfaces and for finding the principal locus associated with a sample of trees. Simulation studies demonstrate that these algorithms perform well, and analyses of two datasets, containing Apicomplexa and African coelacanth genomes respectively, reveal important structure from the second principal components.

Introduction to the special issue: Tree invasions: towards a better understanding of their complex evolutionary dynamics.

PubMed

Hirsch, Heidi; Richardson, David M; Le Roux, Johannes J

2017-05-01

Many invasive plants show evidence of trait-based evolutionary change, but these remain largely unexplored for invasive trees. The increasing number of invasive trees and their tremendous impacts worldwide, however, illustrates the urgent need to bridge this knowledge gap to apply efficient management. Consequently, an interdisciplinary workshop, held in 2015 at Stellenbosch University in Stellenbosch, South Africa, brought together international researchers to discuss our understanding of evolutionary dynamics in invasive trees. The main outcome of this workshop is this Special Issue of AoB PLANTS . The collection of papers in this issue has helped to identify and assess the evolutionary mechanisms that are likely to influence tree invasions. It also facilitated expansion of the unified framework for biological invasions to incorporate key evolutionary processes. The papers cover a wide range of evolutionary mechanisms in tree genomes (adaptation), epigenomes (phenotypic plasticity) and their second genomes (mutualists), and show how such mechanisms can impact tree invasion processes and management. The special issue provides a comprehensive overview of the factors that promote and mitigate the invasive success of tree species in many parts of the world. It also shows that incorporating evolutionary concepts is crucial for understanding the complex drivers of tree invasions and has much potential to improve management. The contributions of the special issue also highlight many priorities for further work in the face of ever-increasing tree invasions; the complexity of this research needs calls for expanded interdisciplinary research collaborations.

Polymorphisms in the AOX2 gene are associated with the rooting ability of olive cuttings.

PubMed

Hedayati, Vahideh; Mousavi, Amir; Razavi, Khadijeh; Cultrera, Nicolò; Alagna, Fiammetta; Mariotti, Roberto; Hosseini-Mazinani, Mehdi; Baldoni, Luciana

2015-07-01

Different rooting ability candidate genes were tested on an olive cross progeny. Our results demonstrated that only the AOX2 gene was strongly induced. OeAOX2 was fully characterised and correlated to phenotypical traits. The formation of adventitious roots is a key step in the vegetative propagation of trees crop species, and this ability is under strict genetic control. While numerous studies have been carried out to identify genes controlling adventitious root formation, only a few loci have been characterised. In this work, candidate genes that were putatively involved in rooting ability were identified in olive (Olea europaea L.) by similarity with orthologs identified in other plant species. The mRNA levels of these genes were analysed by real-time PCR during root induction in high- (HR) and low-rooting (LR) individuals. Interestingly, alternative oxidase 2 (AOX2), which was previously reported to be a functional marker for rooting in olive cuttings, showed a strong induction in HR individuals. From the OeAOX2 full-length gene, alleles and effective polymorphisms were distinguished and analysed in the cross progeny, which were segregated based on rooting. The results revealed a possible correlation between two single nucleotide polymorphisms of OeAOX2 gene and rooting ability.

Adaptive Cluster Sampling for Forest Inventories

Treesearch

Francis A. Roesch

1993-01-01

Adaptive cluster sampling is shown to be a viable alternative for sampling forests when there are rare characteristics of the forest trees which are of interest and occur on clustered trees. The ideas of recent work in Thompson (1990) have been extended to the case in which the initial sample is selected with unequal probabilities. An example is given in which the...

Response of 1- to 4-Year-Old Upland Hardwood Stands to Stocking and Site Manipulations

Treesearch

Jamie L. Schuler; Daniel J. Robison

2002-01-01

The growth and development of very young natural even-aged hardwood stands is not well understood. The relative importance of biotic and abiotic constraints such as overstocking, herbaceous competition, tree nutrition, and pest impacts have not been widely studied in these types of stands. Earlier work has demonstrated significant tree growth response (2- to 20-fold)...

Northeastern FIA Tree Taper Study: Current Status and Future Work

Treesearch

James A. Westfall; Charles T. Scott

2005-01-01

The northeastern unit of the Forest Inventory and Analysis program (NE-FIA) is engaged in an ongoing project to develop regionwide tree taper equations. Sampling intensity is based on NE-FIA plot data and is stratified by species, diameter class, and height class. To date, modeling research has been aimed largely at evaluating existing model forms (and hybrids thereof...

Predicting Tree Mortality From Diameter Growth: A Comparison of Maximum Likelihood and Bayesian Approaches

Treesearch

Peter H. Wychoff; James S. Clark

2000-01-01

Ecologists and foresters have long noted a link between tree growth rate and mortality, and recent work suggests that i&erspecific differences in low growth tolerauce is a key force shaping forest structure. Little information is available, however, on the growth-mortality relationship for most species. We present three methods for estimating growth-mortality...

The ecology, distribution, conservation and management of large old trees.

PubMed

Lindenmayer, David B; Laurance, William F

2017-08-01

Large old trees are some of the most iconic biota on earth and are integral parts of many terrestrial ecosystems including those in tropical, temperate and boreal forests, deserts, savannas, agro-ecological areas, and urban environments. In this review, we provide new insights into the ecology, function, evolution and management of large old trees through broad cross-disciplinary perspectives from literatures in plant physiology, growth and development, evolution, habitat value for fauna and flora, and conservation management. Our review reveals that the diameter, height and longevity of large old trees varies greatly on an inter-specific basis, thereby creating serious challenges in defining large old trees and demanding an ecosystem- and species-specific definition that will only rarely be readily transferable to other species or ecosystems. Such variation is also manifested by marked inter-specific differences in the key attributes of large old trees (beyond diameter and height) such as the extent of buttressing, canopy architecture, the extent of bark micro-environments and the prevalence of cavities. We found that large old trees play an extraordinary range of critical ecological roles including in hydrological regimes, nutrient cycles and numerous ecosystem processes. Large old trees strongly influence the spatial and temporal distribution and abundance of individuals of the same species and populations of numerous other plant and animal species. We suggest many key characteristics of large old trees such as extreme height, prolonged lifespans, and the presence of cavities - which confer competitive and evolutionary advantages in undisturbed environments - can render such trees highly susceptible to a range of human influences. Large old trees are vulnerable to threats ranging from droughts, fire, pests and pathogens, to logging, land clearing, landscape fragmentation and climate change. Tackling such diverse threats is challenging because they often interact and manifest in different ways in different ecosystems, demanding targeted species- or ecosystem-specific responses. We argue that novel management actions will often be required to protect existing large old trees and ensure the recruitment of new cohorts of such trees. For example, fine-scale tree-level conservation such as buffering individual stems will be required in many environments such as in agricultural areas and urban environments. Landscape-level approaches like protecting places where large old trees are most likely to occur will be needed. However, this brings challenges associated with likely changes in tree distributions associated with climate change, because long-lived trees may presently exist in places unsuitable for the development of new cohorts of the same species. Appropriate future environmental domains for a species could exist in new locations where it has never previously occurred. The future distribution and persistence of large old trees may require controversial responses including assisted migration via seed or seedling establishment in new locales. However, the effectiveness of such approaches may be limited where key ecological features of large old trees (such as cavity presence) depend on other species such as termites, fungi and bacteria. Unless other species with similar ecological roles are present to fulfil these functions, these taxa might need to be moved concurrently with the target tree species. © 2016 Cambridge Philosophical Society.

Post-1980 shifts in the sensitivity of boreal tree growth to North Atlantic Ocean dynamics and seasonal climate. Tree growth responses to North Atlantic Ocean dynamics

NASA Astrophysics Data System (ADS)

Ols, Clémentine; Trouet, Valerie; Girardin, Martin P.; Hofgaard, Annika; Bergeron, Yves; Drobyshev, Igor

2018-06-01

The mid-20th century changes in North Atlantic Ocean dynamics, e.g. slow-down of the Atlantic meridional overturning thermohaline circulation (AMOC), have been considered as early signs of tipping points in the Earth climate system. We hypothesized that these changes have significantly altered boreal forest growth dynamics in northeastern North America (NA) and northern Europe (NE), two areas geographically adjacent to the North Atlantic Ocean. To test our hypothesis, we investigated tree growth responses to seasonal large-scale oceanic and atmospheric indices (the AMOC, North Atlantic Oscillation (NAO), and Arctic Oscillation (AO)) and climate (temperature and precipitation) from 1950 onwards, both at the regional and local levels. We developed a network of 6876 black spruce (NA) and 14437 Norway spruce (NE) tree-ring width series, extracted from forest inventory databases. Analyses revealed post-1980 shifts from insignificant to significant tree growth responses to summer oceanic and atmospheric dynamics both in NA (negative responses to NAO and AO indices) and NE (positive response to NAO and AMOC indices). The strength and sign of these responses varied, however, through space with stronger responses in western and central boreal Quebec and in central and northern boreal Sweden, and across scales with stronger responses at the regional level than at the local level. Emerging post-1980 associations with North Atlantic Ocean dynamics synchronized with stronger tree growth responses to local seasonal climate, particularly to winter temperatures. Our results suggest that ongoing and future anomalies in oceanic and atmospheric dynamics may impact forest growth and carbon sequestration to a greater extent than previously thought. Cross-scale differences in responses to North Atlantic Ocean dynamics highlight complex interplays in the effects of local climate and ocean-atmosphere dynamics on tree growth processes and advocate for the use of different spatial scales in climate-growth research to better understand factors controlling tree growth.

Tree-based modeling of complex interactions of phosphorus loadings and environmental factors.

PubMed

Grunwald, S; Daroub, S H; Lang, T A; Diaz, O A

2009-06-01

Phosphorus (P) enrichment has been observed in the historic oligotrophic Greater Everglades in Florida mainly due to P influx from upstream, agriculturally dominated, low relief drainage basins of the Everglades Agricultural Area (EAA). Our specific objectives were to: (1) investigate relationships between various environmental factors and P loads in 10 farm basins within the EAA, (2) identify those environmental factors that impart major effects on P loads using three different tree-based modeling approaches, and (3) evaluate predictive models to assess P loads. We assembled thirteen environmental variable sets for all 10 sub-basins characterizing water level management, cropping practices, soils, hydrology, and farm-specific properties. Drainage flow and P concentrations were measured at each sub-basin outlet from 1992-2002 and aggregated to derive monthly P loads. We used three different tree-based models including single regression trees (ST), committee trees in Bagging (CTb) and ARCing (CTa) modes and ten-fold cross-validation to test prediction performances. The monthly P loads (MPL) during the monitoring period showed a maximum of 2528 kg (mean: 103 kg) and maximum monthly unit area P loads (UAL) of 4.88 kg P ha(-1) (mean: 0.16 kg P ha(-1)). Our results suggest that hydrologic/water management properties are the major controlling variables to predict MPL and UAL in the EAA. Tree-based modeling was successful in identifying relationships between P loads and environmental predictor variables on 10 farms in the EAA indicated by high R(2) (>0.80) and low prediction errors. Committee trees in ARCing mode generated the best performing models to predict P loads and P loads per unit area. Tree-based models had the ability to analyze complex, non-linear relationships between P loads and multiple variables describing hydrologic/water management, cropping practices, soil and farm-specific properties within the EAA.

Using simple artificial intelligence methods for predicting amyloidogenesis in antibodies

PubMed Central

2010-01-01

Background All polypeptide backbones have the potential to form amyloid fibrils, which are associated with a number of degenerative disorders. However, the likelihood that amyloidosis would actually occur under physiological conditions depends largely on the amino acid composition of a protein. We explore using a naive Bayesian classifier and a weighted decision tree for predicting the amyloidogenicity of immunoglobulin sequences. Results The average accuracy based on leave-one-out (LOO) cross validation of a Bayesian classifier generated from 143 amyloidogenic sequences is 60.84%. This is consistent with the average accuracy of 61.15% for a holdout test set comprised of 103 AM and 28 non-amyloidogenic sequences. The LOO cross validation accuracy increases to 81.08% when the training set is augmented by the holdout test set. In comparison, the average classification accuracy for the holdout test set obtained using a decision tree is 78.64%. Non-amyloidogenic sequences are predicted with average LOO cross validation accuracies between 74.05% and 77.24% using the Bayesian classifier, depending on the training set size. The accuracy for the holdout test set was 89%. For the decision tree, the non-amyloidogenic prediction accuracy is 75.00%. Conclusions This exploratory study indicates that both classification methods may be promising in providing straightforward predictions on the amyloidogenicity of a sequence. Nevertheless, the number of available sequences that satisfy the premises of this study are limited, and are consequently smaller than the ideal training set size. Increasing the size of the training set clearly increases the accuracy, and the expansion of the training set to include not only more derivatives, but more alignments, would make the method more sound. The accuracy of the classifiers may also be improved when additional factors, such as structural and physico-chemical data, are considered. The development of this type of classifier has significant applications in evaluating engineered antibodies, and may be adapted for evaluating engineered proteins in general. PMID:20144194

Using simple artificial intelligence methods for predicting amyloidogenesis in antibodies.

PubMed

David, Maria Pamela C; Concepcion, Gisela P; Padlan, Eduardo A

2010-02-08

All polypeptide backbones have the potential to form amyloid fibrils, which are associated with a number of degenerative disorders. However, the likelihood that amyloidosis would actually occur under physiological conditions depends largely on the amino acid composition of a protein. We explore using a naive Bayesian classifier and a weighted decision tree for predicting the amyloidogenicity of immunoglobulin sequences. The average accuracy based on leave-one-out (LOO) cross validation of a Bayesian classifier generated from 143 amyloidogenic sequences is 60.84%. This is consistent with the average accuracy of 61.15% for a holdout test set comprised of 103 AM and 28 non-amyloidogenic sequences. The LOO cross validation accuracy increases to 81.08% when the training set is augmented by the holdout test set. In comparison, the average classification accuracy for the holdout test set obtained using a decision tree is 78.64%. Non-amyloidogenic sequences are predicted with average LOO cross validation accuracies between 74.05% and 77.24% using the Bayesian classifier, depending on the training set size. The accuracy for the holdout test set was 89%. For the decision tree, the non-amyloidogenic prediction accuracy is 75.00%. This exploratory study indicates that both classification methods may be promising in providing straightforward predictions on the amyloidogenicity of a sequence. Nevertheless, the number of available sequences that satisfy the premises of this study are limited, and are consequently smaller than the ideal training set size. Increasing the size of the training set clearly increases the accuracy, and the expansion of the training set to include not only more derivatives, but more alignments, would make the method more sound. The accuracy of the classifiers may also be improved when additional factors, such as structural and physico-chemical data, are considered. The development of this type of classifier has significant applications in evaluating engineered antibodies, and may be adapted for evaluating engineered proteins in general.

Spatial Distribution and Site-Specific Spraying of Main Sucking Pests of Elm Trees.

PubMed

Karimzadeh, R; Iranipour, S

2017-06-01

Elm trees are important landscape trees and sucking insects weaken the elm trees and produce large amounts of honeydew. The main objectives of this study were to identify main honeydew-producing pests of elm trees and do site-specific spraying against these pests. To map the spatial distribution of the sucking pests in the large scale, the study area was divided into 40 × 40 m grids and one tree was chosen randomly from each grid (a total of 55 trees). These trees were sampled twice a year in 2011 and 2012. Each sample was a 30-cm branch terminal. Eight samples were taken from each tree in four cardinal directions and two canopy levels. The number of sucking insects and leaves of each sample were counted and recorded. Spatial analysis of the data was carried out using geostatistics. Kriging was used for producing prediction maps. Insecticide application was restricted to the regions with populations higher than threshold. To identify within-tree distribution of the honeydew-producing pests, six and four elm trees were chosen in 2011 and 2012 respectively, and sampled weekly. These trees were sampled as described previously. European elm scale (EES), Gossyparia spuria (Modeer) and two species of aphids were the dominant honeydew-producing pests. The results revealed that the effects of direction, canopy level and their interactions on insect populations were not statistically significant (P < 0.05). Site-specific spraying decreased the amount of insecticides used by ca. 20%, while satisfactory control of the sucking pests and honeydew excretion was obtained. Considering the environmental and economic benefits of site-specific spraying, it is worth doing more complementary works in this area.

Evaluation of growth disturbances of Picea abies (L.) Karst. to disturbances caused by landslide movements

NASA Astrophysics Data System (ADS)

Šilhán, Karel

2017-01-01

Dendrogeomorphic methods are frequently used in landslide analyses. Although methods of landslide dating based on tree rings are well developed, they still indicated many questions. The aim of this study was to evaluate the frequently used theoretical scheme based on the event-response relationship. Seventy-four individuals of Norway spruce (Picea abies (L.) Karst.) exhibiting visible external disturbance, were sampled on the Girová landslide (the largest historical flow-like landslide in the Czech Republic). This landslide reactivated in May 2010, and post-landslide tree growth responses were studied in detail. These growth responses were compared with the intensity and occurrence of visible external tree disturbance: tilted stems, damaged root systems, and decapitation. Twenty-nine trees (39.2%) died within one to four years following the 2010 landslide movement. The trees that died following the landslide movement were significantly younger and displayed significantly greater stem tilting than the live trees. Abrupt growth suppression was a more-frequent response among the dead trees, whereas growth release dominated among the live trees. Only two trees (2.7%) created no reaction wood in response to the landslide movement. Forty-four percent of the trees started to produce reaction wood structure after a delay, which generally spanned one year. Some eccentric growth was evident in the tree rings of the landslide year and was significant in the first years following the landslide movement. Missing rings were observed only on the upper sides of the stems, and no false tree rings were observed. The results confirm the general validity of event-response relationship, nevertheless this study points out the limitations and uncertainties of this generally accepted working scheme.

Seasonal distributions of the western cherry fruit fly (Diptera: Tephritidae) among host and nonhost fruit trees.

PubMed

Yee, Wee L

2014-01-01

Seasonal distributions of the western cherry fruit fly, Rhagoletis indifferens Curran (Diptera: Tephritidae), in sweet cherry (Prunus avium (L.) L.) (major host), black hawthorn (occasional developmental host) (Crataegus douglasii Lindley), and other trees were determined in a ponderosa pine ecosystem in Washington state, USA. The hypothesis that most fly dispersal from cherry trees occurs after fruit senesce or drop was tested, with emphasis on movement to black hawthorn trees. Sweet cherry fruit developed earlier than black hawthorn, bitter cherry (common host), choke cherry, and apple fruit. Flies were usually captured first in sweet cherry trees but were caught in bitter cherry and other trees throughout the season. Peak fly capture periods in sweet cherry began around the same time or slightly earlier than in other trees. However, peak fly capture periods in black hawthorn and other nonsweet cherry trees continued after peak periods in sweet cherry ended, or relative fly numbers within sweet cherry declined more quickly than those within other trees. Larvae were reared from sweet and bitter cherry but not black hawthorn fruit. Results provide partial support for the hypothesis in that although R. indifferens commonly disperses from sweet cherry trees with fruit, it could disperse more, or more flies are retained in nonsweet cherry trees after than before sweet cherries drop. This could allow opportunities for the flies to use other fruit for larval development. Although R. indifferens infestation in black hawthorn was not detected, early season fly dispersal to this and other trees and fly presence in bitter cherry could make fly management in sweet cherry difficult. Published by Oxford University Press on behalf of the Entomological Society of America 2014. This work is written by a US Government employee and is in the public domain in the US.

ARAMIS project: a comprehensive methodology for the identification of reference accident scenarios in process industries.

PubMed

Delvosalle, Christian; Fievez, Cécile; Pipart, Aurore; Debray, Bruno

2006-03-31

In the frame of the Accidental Risk Assessment Methodology for Industries (ARAMIS) project, this paper aims at presenting the work carried out in the part of the project devoted to the definition of accident scenarios. This topic is a key-point in risk assessment and serves as basis for the whole risk quantification. The first result of the work is the building of a methodology for the identification of major accident hazards (MIMAH), which is carried out with the development of generic fault and event trees based on a typology of equipment and substances. The term "major accidents" must be understood as the worst accidents likely to occur on the equipment, assuming that no safety systems are installed. A second methodology, called methodology for the identification of reference accident scenarios (MIRAS) takes into account the influence of safety systems on both the frequencies and possible consequences of accidents. This methodology leads to identify more realistic accident scenarios. The reference accident scenarios are chosen with the help of a tool called "risk matrix", crossing the frequency and the consequences of accidents. This paper presents both methodologies and an application on an ethylene oxide storage.

Detection of chewing from piezoelectric film sensor signals using ensemble classifiers.

PubMed

Farooq, Muhammad; Sazonov, Edward

2016-08-01

Selection and use of pattern recognition algorithms is application dependent. In this work, we explored the use of several ensembles of weak classifiers to classify signals captured from a wearable sensor system to detect food intake based on chewing. Three sensor signals (Piezoelectric sensor, accelerometer, and hand to mouth gesture) were collected from 12 subjects in free-living conditions for 24 hrs. Sensor signals were divided into 10 seconds epochs and for each epoch combination of time and frequency domain features were computed. In this work, we present a comparison of three different ensemble techniques: boosting (AdaBoost), bootstrap aggregation (bagging) and stacking, each trained with 3 different weak classifiers (Decision Trees, Linear Discriminant Analysis (LDA) and Logistic Regression). Type of feature normalization used can also impact the classification results. For each ensemble method, three feature normalization techniques: (no-normalization, z-score normalization, and minmax normalization) were tested. A 12 fold cross-validation scheme was used to evaluate the performance of each model where the performance was evaluated in terms of precision, recall, and accuracy. Best results achieved here show an improvement of about 4% over our previous algorithms.

Potassium nutrition and water availability affect phloem transport of photosynthetic carbon in eucalypt trees

NASA Astrophysics Data System (ADS)

Epron, Daniel; Cabral, Osvaldo; Laclau, Jean-Paul; Dannoura, Masako; Packer, Ana Paula; Plain, Caroline; Battie-Laclau, Patricia; Moreira, Marcelo; Trivelin, Paulo; Bouillet, Jean-Pierre; Gérant, Dominique; Nouvellon, Yann

2015-04-01

Potassium fertilisation strongly affects growth and carbon partitioning of eucalypt on tropical soil that are strongly weathered. In addition, potassium fertilization could be of great interest in mitigating the adverse consequences of drought in planted forests, as foliar K concentrations influence osmotic adjustment, stomatal regulation and phloem loading. Phloem is the main pathway for transferring photosynthate from source leaves to sink organs, thus controlling growth partitioning among the different tree compartments. But little is known about the effect of potassium nutrition on phloem transport of photosynthetic carbon and on the interaction between K nutrition and water availability. In situ 13C pulse labelling was conducted on tropical eucalypt trees (Eucalyptus grandis L.) grown in a trial plantation with plots in which 37% of throughfall were excluded (about 500 mm/yr) using home-made transparent gutters (-W) or not (+W) and plots that received 0.45 mol K m-2 applied as KCl three months after planting (+K) or not (-K). Three trees were labelled in each of the four treatments (+K+W, +K-W, -K+W and -K-W). Trees were labelled for one hour by injecting pure 13CO2 in a 27 m3 whole crown chamber. We estimated the velocity of carbon transfer in the trunk by comparing time lags between the uptake of 13CO2 and its recovery in trunk CO2 efflux recorded by off axis integrated cavity output spectroscopy (Los Gatos Research) in two chambers per tree, one just under the crown and one at the base of the trunk. We analyzed the dynamics of the label recovered in the foliage and in the phloem sap by analysing carbon isotope composition of bulk leaf organic matter and phloem extracts using an isotope ratio mass spectrometer. The velocity of carbon transfer in the trunk and the initial rate 13C disappearance from the foliage were much higher in +K trees than in -K trees with no significant effect of rainfall. The volumetric flow of phloem, roughly estimated by multiplying the velocity of C transfer with the bark cross-section area of tree at 1.30m high, was also higher in +K trees than in -K trees and well-correlated with crown photosynthesis and with the xylem sapflow density.

Tracking Trends in Fractional Forest Cover Change using Long Term Data from AVHRR and MODIS

NASA Astrophysics Data System (ADS)

Kim, D. H.; DiMiceli, C.; Sohlberg, R. A.; Hansen, M.; Carroll, M.; Kelly, M.; Townshend, J. R.

2014-12-01

Tree cover affects terrestrial energy and water exchanges, photosynthesis and transpiration, net primary production, and carbon and nutrient fluxes. Accurate and long-term continuous observation of tree cover change is critical for the study of the gradual ecosystem change. Tree cover is most commonly inferred from categorical maps which may inadequately represent within-class heterogeneity for many analyses. Alternatively, Vegetation Continuous Fields data measures fractions or proportions of pixel area. Recent development in remote sensing data processing and cross sensor calibration techniques enabled the continuous, long-term observations such as Land Long-Term Data Records. Such data products and their surface reflectance data have enhanced the possibilities for long term Vegetation Continuous Fields data, thus enabling the estimation of long term trend of fractional forest cover change. In this presentation, we will summarize the progress in algorithm development including automation of training selection for deciduous and evergreen forest, the preliminary results, and its future applications to relate trends in fractional forest cover change and environmental change.

Sulfur in Cometary Dust

NASA Technical Reports Server (NTRS)

Fomenkova, M. N.

1997-01-01

The computer-intensive project consisted of the analysis and synthesis of existing data on composition of comet Halley dust particles. The main objective was to obtain a complete inventory of sulfur containing compounds in the comet Halley dust by building upon the existing classification of organic and inorganic compounds and applying a variety of statistical techniques for cluster and cross-correlational analyses. A student hired for this project wrote and tested the software to perform cluster analysis. The following tasks were carried out: (1) selecting the data from existing database for the proposed project; (2) finding access to a standard library of statistical routines for cluster analysis; (3) reformatting the data as necessary for input into the library routines; (4) performing cluster analysis and constructing hierarchical cluster trees using three methods to define the proximity of clusters; (5) presenting the output results in different formats to facilitate the interpretation of the obtained cluster trees; (6) selecting groups of data points common for all three trees as stable clusters. We have also considered the chemistry of sulfur in inorganic compounds.

Lack of host specificity leads to independent assortment of dipterocarps and ectomycorrhizal fungi across a soil fertility gradient.

PubMed

Peay, Kabir G; Russo, Sabrina E; McGuire, Krista L; Lim, Zhenyu; Chan, Ju Ping; Tan, Sylvester; Davies, Stuart J

2015-08-01

Plants interact with a diversity of microorganisms, and there is often concordance in their community structures. Because most community-level studies are observational, it is unclear if such concordance arises because of host specificity, in which microorganisms or plants limit each other's occurrence. Using a reciprocal transplant experiment, we tested the hypothesis that host specificity between trees and ectomycorrhizal fungi determines patterns of tree and fungal soil specialisation. Seedlings of 13 dipterocarp species with contrasting soil specialisations were seeded into plots crossing soil type and canopy openness. Ectomycorrhizal colonists were identified by DNA sequencing. After 2.5 years, we found no evidence of host specificity. Rather, soil environment was the primary determinant of ectomycorrhizal diversity and composition on seedlings. Despite their close symbiosis, our results show that ectomycorrhizal fungi and tree communities in this Bornean rain forest assemble independently of host-specific interactions, raising questions about how mutualism shapes the realised niche. © 2015 John Wiley & Sons Ltd/CNRS.

Nonannual tree rings in a climate-sensitive Prioria copaifera chronology in the Atrato River, Colombia.

PubMed

Herrera-Ramirez, David; Andreu-Hayles, Laia; Del Valle, Jorge I; Santos, Guaciara M; Gonzalez, Paula L M

2017-08-01

In temperate climates, tree growth dormancy usually ensures the annual nature of tree rings, but in tropical environments, determination of annual periodicity can be more complex. The purposes of the work are as follows: (1) to generate a reliable tree-ring width chronology for Prioria copaifera Griseb. (Leguminoceae), a tropical tree species dwelling in the Atrato River floodplains, Colombia; (2) to assess the climate signal recorded by the tree-ring records; and (3) to validate the annual periodicity of the tree rings using independent methods. We used standard dendrochronological procedures to generate the P. copaifera tree-ring chronology. We used Pearson correlations to evaluate the relationship of the chronology with the meteorological records, climate regional indices, and gridded precipitation/sea surface temperature products. We also evaluated 24 high-precision 14 C measurements spread over a range of preselected tree rings, with assigned calendar years by dendrochronological techniques, before and after the bomb spike in order to validate the annual nature of the tree rings. The tree-ring width chronology was statistically reliable, and it correlated significantly with local records of annual and October-December (OND) streamflow and precipitation across the upper river watershed (positive), and OND temperature (negative). It was also significantly related to the Oceanic Niño Index, Pacific Decadal Oscillation, and the Southern Oscillation Index, as well as sea surface temperatures over the Caribbean and the Pacific region. However, 14 C high-precision measurements over the tree rings demonstrated offsets of up to 40 years that indicate that P. copaifera can produce more than one ring in certain years. Results derived from the strongest climate-growth relationship during the most recent years of the record suggest that the climatic signal reported may be due to the presence of annual rings in some of those trees in recent years. Our study alerts about the risk of applying dendrochronology in species with challenging anatomical features defining tree rings, commonly found in the tropics, without an independent validation of annual periodicity of tree rings. High-precision 14 C measurements in multiple trees are a useful method to validate the identification of annual tree rings.

Some climatic indicators in the period A.D. 1200-1400 in New Mexico

USGS Publications Warehouse

Leopold, Luna Bergere; Leopold, Estella B.; Wendorf, F.

1963-01-01

Three centuries before Columbus landed in America, the alluvial valleys of the south-western United States teemed with activity. The indigenous peoples had been building for 300 years a culture centred around community life based on flood-water farming and on hunting. A large number of pueblos had developed on sites earlier occupied by pit-house people. Community organization had brought advances in the ceramic and decorative arts, and changes in these artistic activities were sufficiently rapid that accurate chronologies have become available through the work of archaeologists during the twentieth century. These chronologies were at first unrelated to absolute dates, but the excavations of the 1920s at Chaco Canyon (New Mexico) provided the materials through which absolute dates could be established. This was accomplished by matching the changes in tree-ring width backward in time from living trees through successively older samples. Trees overlapping in age provided, by unique successions of distinctive tree-ring widths, a calendar by which individual logs could be dated. Beams found in the excavations at Chaco Canyon gave the first material by which the cultural developments culminating about A.D. 1300 could be dated.As a result of the time sequence provided by the tree-ring calendar, the dates within which different pottery types were developed could be accurately established. The dates of pottery types have been checked at a sufficiently large number of sites throughout the south-western United States that absolute dating of a large number of distinctive patterns can be considered unassailable. The sequence of tree-ring widths gives some climatic indications of great interest both to archaeologists and to climatologists. A relatively large number of logs spanning the period from A.D. 1200 to 1300 and, in particular, the years between 1276 and 1299, indicate that this period was generally characterized by smaller tree-ring widths than in the centuries immediately before and after. As a first approximation, the hundred years of narrow tree-ring widths were interpreted as a time of relative aridity, and have been referred to as the “Pueblo Drought”. More recent studies of tree-ring widths using sophisticated statistical techniques have thrown some doubts on any direct correlation of tree-ring widths with rainfall. Such doubts have been put forward before by Glock (1955) whose studies have been aimed at separating the various effects of seasonal occurrence of precipitation, the amount falling in various seasons, and other climatic factors in their relative influence on tree-ring widths. At present, then, tree-ring widths may be considered more satisfactory for reading chronology than for reading climate. It is this concern about direct correlation of tree-ring width with climate that led to initiation of the present study. This work is a preliminary attempt to obtain independent evidence from pollen concerning the probable nature of the vegetation and thus the climate in a period known to be characterized by narrow tree rings.

The Potential for Harvesting Energy from the Movement of Trees

PubMed Central

McGarry, Scott; Knight, Chris

2011-01-01

Over the last decade, wireless devices have decreased in size and power requirements. These devices generally use batteries as a power source but can employ additional means of power, such as solar, thermal or wind energy. However, sensor networks are often deployed in conditions of minimal lighting and thermal gradient such as densely wooded environments, where even normal wind energy harvesting is limited. In these cases a possible source of energy is from the motion of the trees themselves. We investigated the amount of energy and power available from the motion of a tree in a sheltered position, during Beaufort 4 winds. We measured the work performed by the tree to lift a mass, we measured horizontal acceleration of free movement, and we determined the angular deflection of the movement of the tree trunk, to determine the energy and power available to various types of harvesting devices. We found that the amount of power available from the tree, as demonstrated by lifting a mass, compares favourably with the power required to run a wireless sensor node. PMID:22163695