Science.gov

Sample records for honeylocust trees

  1. Water requirements of honeylocust (Gleditsia triacanthos f. inermis) in the urban forest

    Treesearch

    Howard G. Halverson; Donald F. Potts

    1981-01-01

    Water use by an urban tree was measured lysimetrically while water use by the same tree at a non-urban site was estimated by a model. Comparison of the measured and estimated water use showed that the urban honeylocust (Gleditsia triacanthos f. inermis) required an average of 155 percent of the water needed by the same tree...

  2. Performance of Asian longhorned beetle among tree species

    Treesearch

    Kelli Hoover; Scott Ludwig; James Sellmer; Deborah McCullough; Laura Lazarus

    2003-01-01

    Two procedures were evaluated for assessing susceptibility of a variety of tree species to Anoplophora glabripennis. In the first procedure, adult beetles were caged with a section of sugar maple, northern red oak, white oak, honeylocust, eastern cottonwood, sycamore or tulip poplar wood and allowed to oviposit.

  3. Effects of aluminum on growth, development, and nutrient composition of honeylocust (Gleditsia triacanthos L.) seedlings.

    PubMed

    Thornton, F. C.; Schaedle, M.; Raynal, D. J.

    1986-12-01

    Hydroponic experiments were conducted to determine the effects of aluminum (Al) on root development, shoot morphology and the nutrient composition of honeylocust seedlings (Gleditsia triacanthos L.). Seedlings were grown at pH 4 in a nutrient solution containing 0, 50, 150, 600 or 1500 microM Al. Within seven days, there were significant differences in root growth and root nutrient composition between control seedlings and seedlings grown in the presence of 150 or 600 microM Al. By day 14, significant reductions in leaf production and plant height were observed in seedlings treated with 1500 microM Al. At the lowest Al concentration, 50 microM, leaf size and expansion rates were significantly lower than in the controls. By the third week of the experiment, Ca and Mg concentrations in young leaves of the Al-treated seedlings were significantly lower than in leaves of control plants. Analysis of old leaf tissue, however, revealed no consistent pattern of nutrient concentration with Al treatment.

  4. Methods to Evaluate Host Tree Suitability to the Asian Long horned Beetle, Anoplophora glabripennis

    Treesearch

    Scott W. Ludwig; Laura Lazarus; Deborah G. McCullough; Kelli Hoover; Silvia Montero; James C. Sellmer

    2002-01-01

    Two procedures were evaluated for assessing tree susceptibility to Anaplophora glabripennis. In the first procedure, adult beetles were caged with a section of sugar maple, northern red oak, white oak, honeylocust, eastern cottonwood, sycamore or tulip poplar wood Results showed that females laid viable eggs on sugar maple, red oak, white oak and...

  5. Soil acidity, and the growth, biomass partitioning and leaf mineral composition of honeylocust (Gleditsia triacanthos L.) seedlings.

    PubMed

    Schindelbeck, R R; Riha, S J

    1988-12-01

    Honeylocust seedlings (Gleditsia triacanthos L.) were grown in cylinders containing soil adjusted to pH 4, 5 or 6, and harvested every 10 days for 40 days for dry weight and leaf mineral analysis. Total weight of plants grown at pH 4 was less than that of plants grown at pH 5 or 6. Root weight accounted for a greater proportion of total weight in plants grown at pH 4 than in plants grown at pH 5 or 6. Root growth as a function of total plant growth was higher in plants grown at pH 4 than in plants grown at pH 5 or 6, whereas leaf growth as a function of total plant growth was less in plants grown at pH 4 than in plants grown at pH 5 or 6. However, the relationships between root biomass and root length and between leaf biomass and leaf area were the same in all treatments. An analysis of total leaf concentrations of Ca, P, K, Mg, Mn and Al indicated that Al accumulation in leaves was significantly related to a decrease in plant growth at pH 5. A leaf tissue aluminum concentration of 35 microg g(-1) was associated with toxicity symptoms and a 25% reduction in total plant weight.

  6. Trees

    ERIC Educational Resources Information Center

    Al-Khaja, Nawal

    2007-01-01

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

  7. Alcohol co-production from tree crops

    SciTech Connect

    Seibert, M.; Folger, G.; Milne, T.

    1982-06-01

    A concept for the sustainable production of alcohol from fermentable substrates produced on an annual basis by the reproductive organs (pods, fruits, nuts, berries, etc.) of tree crops is presented. The advantages of tree-crop systems include suitability for use on marginal land, potential productivity equivalent to row crops, minimal maintenance and energy-input requirements, environmental compatibility, and the possibility of co-product production. Honeylocust, mesquite, and persimmon are examined as potential US tree-crop species. Other species not previously considered, including osage orange and breadfruit, are suggested as tree-crop candidates for North America and the tropical developing world, respectively. Fermentation of tree-crop organs and the economics of tree-crop systems are also discussed. Currently the greatest area of uncertainty lies in actual pod or fruit yields one can expect from large tree farms under real life conditions. However, ballpark ethanol yield estimates of from 880 to 3470 l hectare/sup -1/ (94 to 400 gal acre/sup -1/) justify further consideration of tree crop systems.

  8. Trees

    NASA Astrophysics Data System (ADS)

    Epstein, Henri

    2016-11-01

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

  9. Advancement of tree species across ecotonal borders into non-forested ecosystems

    NASA Astrophysics Data System (ADS)

    Hanberry, Brice B.; Hansen, Mark H.

    2015-10-01

    Woody species are increasing in density, causing transition to more densely wooded vegetation states, and encroaching across ecotonal borders into non-forested ecosystems. We examined USDA Forest Service Forest Inventory and Analysis data to identify tree species that have expanded longitudinally in range, particularly into the central United States. We analyzed compositional differences within ecological regions (i.e., subsections) in eastern and western ranges of species using repeated measures ANOVA. We considered differences in outer ranges to indicate range expansion or contraction. We also estimated the shift in forest area and basal area relative to the center of the US and compared change in deciduous forest land cover. Out of 80 candidate species, 22 species expanded to the west, seven species expanded to the east, and five species expanded in both directions. During the survey interval, eastern tree species advanced into the predominantly non-forested ecosystems of central United States. Eastern cottonwood, eastern hophornbeam, eastern redbud, honeylocust, Osage-orange, pecan, red mulberry, and Shumard oak represent some of the species that are advancing eastern forest boundaries across forest-grassland ecotones into the central United States. Forest land has shifted towards the center of the continent, as has the center of mean tree basal area, and a simple comparison of deciduous cover change also displayed forest advancement into the central United States from eastern forests. The expanding species may spread along riparian migration corridors that provide protection from drought. Humans use the advancing tree species for windbreaks, fencerows, and ornamental landscaping, while wildlife spread fruit seeds, which results in unintentional assisted migration, or translocation, to drier sites across the region.

  10. Talking Trees

    ERIC Educational Resources Information Center

    Tolman, Marvin

    2005-01-01

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

  11. Talking Trees

    ERIC Educational Resources Information Center

    Tolman, Marvin

    2005-01-01

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

  12. 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…

  13. Audubon Tree Study Program.

    ERIC Educational Resources Information Center

    National Audubon Society, New York, NY.

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

  14. Audubon Tree Study Program.

    ERIC Educational Resources Information Center

    National Audubon Society, New York, NY.

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

  15. Tree harvesting

    SciTech Connect

    Badger, P.C.

    1995-12-31

    Short rotation intensive culture tree plantations have been a major part of biomass energy concepts since the beginning. One aspect receiving less attention than it deserves is harvesting. This article describes an method of harvesting somewhere between agricultural mowing machines and huge feller-bunchers of the pulpwood and lumber industries.

  16. Tree Mortality

    Treesearch

    Mark J. Ambrose

    2012-01-01

    Tree mortality is a natural process in all forest ecosystems. However, extremely high mortality also can be an indicator of forest health issues. On a regional scale, high mortality levels may indicate widespread insect or disease problems. High mortality may also occur if a large proportion of the forest in a particular region is made up of older, senescent stands....

  17. Tree mortality

    Treesearch

    Mark J. Ambrose

    2013-01-01

    Tree mortality is a natural process in all forest ecosystems. However, extremely high mortality can also be an indicator of forest health issues. On a regional scale, high mortality levels may indicate widespread insect or disease problems. High mortality may also occur if a large proportion of the forest in a particular region is made up of older, senescent stands....

  18. Tree mortality

    Treesearch

    Mark J. Ambrose

    2013-01-01

    Tree mortality is a natural process in all forest ecosystems. However, extremely high mortality also can be an indicator of forest health issues. On a regional scale, high mortality levels may indicate widespread insect or disease problems. High mortality may also occur if a large proportion of the forests in a region is made up of older, senescent stands.

  19. Tree Nut Allergies

    MedlinePlus

    ... Luncheon Registration Create Your Own Events Educational Events Tree Nut Allergies Tree nut allergy is one of ... with tree nuts during manufacturing and processing. Avoiding Tree Nuts The federal Food Allergen Labeling and Consumer ...

  20. Technical Tree Climbing.

    ERIC Educational Resources Information Center

    Jenkins, Peter

    Tree climbing offers a safe, inexpensive adventure sport that can be performed almost anywhere. Using standard procedures practiced in tree surgery or rock climbing, almost any tree can be climbed. Tree climbing provides challenge and adventure as well as a vigorous upper-body workout. Tree Climbers International classifies trees using a system…

  1. Exotic trees.

    PubMed

    Burda, Z; Erdmann, J; Petersson, B; Wattenberg, M

    2003-02-01

    We discuss the scaling properties of free branched polymers. The scaling behavior of the model is classified by the Hausdorff dimensions for the internal geometry, d(L) and d(H), and for the external one, D(L) and D(H). The dimensions d(H) and D(H) characterize the behavior for long distances, while d(L) and D(L) for short distances. We show that the internal Hausdorff dimension is d(L)=2 for generic and scale-free trees, contrary to d(H), which is known to be equal to 2 for generic trees and to vary between 2 and infinity for scale-free trees. We show that the external Hausdorff dimension D(H) is directly related to the internal one as D(H)=alphad(H), where alpha is the stability index of the embedding weights for the nearest-vertex interactions. The index is alpha=2 for weights from the Gaussian domain of attraction and 0

  2. What Makes a Tree a Tree?

    ERIC Educational Resources Information Center

    NatureScope, 1986

    1986-01-01

    Provides: (1) background information on trees, focusing on the parts of trees and how they differ from other plants; (2) eight activities; and (3) ready-to-copy pages dealing with tree identification and tree rings. Activities include objective(s), recommended age level(s), subject area(s), list of materials needed, and procedures. (JN)

  3. Trees are good, but…

    Treesearch

    E.G. McPherson; F. Ferrini

    2010-01-01

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

  4. Trees in the Landscape.

    ERIC Educational Resources Information Center

    Webb, Richard; Forbatha, Ann

    1982-01-01

    Strategies for using trees in classroom instruction are provided. Includes: (1) activities (such as tree identification, mapping, measuring tree height/width); (2) list of asthetic, architectural, engineering, climate, and wildlife functions of trees; (3) tree discussion questions; and (4) references. (JN)

  5. Simple street tree sampling

    Treesearch

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

    2015-01-01

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

  6. Urban park tree inventories

    Treesearch

    Joe R. McBride; David J. Nowak

    1989-01-01

    A survey of published reports on urban park tree inventories in the United States and the United Kingdom reveal two types of inventories: (1) Tree Location Inventories and (2) Generalized Information Inventories. Tree location inventories permit managers to relocate specific park trees, along with providing individual tree characteristics and condition data. In...

  7. Community Tree Planting Guide

    Treesearch

    Katie Himanga; Douglas Jones; Jean Miller; Janette Monear; Gail Steinman; Katherine Widin

    2001-01-01

    Tree Trust has been helping people plant trees in their communities since 1976. Our goal is to educate people about the importance of trees in their community and guide them through the process of successful tree-planting projects. Franklin Delano Roosevelt once said ?to exist as a nation, to prosper as a state, and to live as a people, we must have trees?....

  8. Additive Similarity Trees

    ERIC Educational Resources Information Center

    Sattath, Shmuel; Tversky, Amos

    1977-01-01

    Tree representations of similarity data are investigated. Hierarchical clustering is critically examined, and a more general procedure, called the additive tree, is presented. The additive tree representation is then compared to multidimensional scaling. (Author/JKS)

  9. Training Tree Transducers

    DTIC Science & Technology

    2004-01-01

    trees (similar to the role played by the finite- state acceptor FSA for strings). We describe the version (equivalent to TSG ( Schabes , 1990)) where...strictly contained in tree sets of tree adjoining gram- mars (Joshi and Schabes , 1997). 4 Extended-LHS Tree Transducers (xR) Section 1 informally described...changes without modifying the training procedure, as long as we stick to tree automata. 10 Related Work Tree substitution grammars or TSG ( Schabes , 1990

  10. Categorizing ideas about trees: a tree of trees.

    PubMed

    Fisler, Marie; Lecointre, Guillaume

    2013-01-01

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

  11. Tree Tectonics

    NASA Astrophysics Data System (ADS)

    Vogt, Peter R.

    2004-09-01

    Nature often replicates her processes at different scales of space and time in differing media. Here a tree-trunk cross section I am preparing for a dendrochronological display at the Battle Creek Cypress Swamp Nature Sanctuary (Calvert County, Maryland) dried and cracked in a way that replicates practically all the planform features found along the Mid-Oceanic Ridge (see Figure 1). The left-lateral offset of saw marks, contrasting with the right-lateral ``rift'' offset, even illustrates the distinction between transcurrent (strike-slip) and transform faults, the latter only recognized as a geologic feature, by J. Tuzo Wilson, in 1965. However, wood cracking is but one of many examples of natural processes that replicate one or several elements of lithospheric plate tectonics. Many of these examples occur in everyday venues and thus make great teaching aids, ``teachable'' from primary school to university levels. Plate tectonics, the dominant process of Earth geology, also occurs in miniature on the surface of some lava lakes, and as ``ice plate tectonics'' on our frozen seas and lakes. Ice tectonics also happens at larger spatial and temporal scales on the Jovian moons Europa and perhaps Ganymede. Tabletop plate tectonics, in which a molten-paraffin ``asthenosphere'' is surfaced by a skin of congealing wax ``plates,'' first replicated Mid-Oceanic Ridge type seafloor spreading more than three decades ago. A seismologist (J. Brune, personal communication, 2004) discovered wax plate tectonics by casually and serendipitously pulling a stick across a container of molten wax his wife and daughters had used in making candles. Brune and his student D. Oldenburg followed up and mirabile dictu published the results in Science (178, 301-304).

  12. Urban tree growth modeling

    Treesearch

    E. Gregory McPherson; Paula J. Peper

    2012-01-01

    This paper describes three long-term tree growth studies conducted to evaluate tree performance because repeated measurements of the same trees produce critical data for growth model calibration and validation. Several empirical and process-based approaches to modeling tree growth are reviewed. Modeling is more advanced in the fields of forestry and...

  13. Keeping trees as assets

    Treesearch

    Kevin T. Smith

    2009-01-01

    Landscape trees have real value and contribute to making livable communities. Making the most of that value requires providing trees with the proper care and attention. As potentially large and long-lived organisms, trees benefit from commitment to regular care that respects the natural tree system. This system captures, transforms, and uses energy to survive, grow,...

  14. The Needs of Trees

    ERIC Educational Resources Information Center

    Boyd, Amy E.; Cooper, Jim

    2004-01-01

    Tree rings can be used not only to look at plant growth, but also to make connections between plant growth and resource availability. In this lesson, students in 2nd-4th grades use role-play to become familiar with basic requirements of trees and how availability of those resources is related to tree ring sizes and tree growth. These concepts can…

  15. The Needs of Trees

    ERIC Educational Resources Information Center

    Boyd, Amy E.; Cooper, Jim

    2004-01-01

    Tree rings can be used not only to look at plant growth, but also to make connections between plant growth and resource availability. In this lesson, students in 2nd-4th grades use role-play to become familiar with basic requirements of trees and how availability of those resources is related to tree ring sizes and tree growth. These concepts can…

  16. Tea tree oil.

    PubMed

    Hartford, Orville; Zug, Kathryn A

    2005-09-01

    Tea tree oil is a popular ingredient in many over-the-counter healthcare and cosmetic products. With the explosion of the natural and alternative medicine industry, more and more people are using products containing tea tree oil. This article reviews basic information about tea tree oil and contact allergy, including sources of tea tree oil, chemical composition, potential cross reactions, reported cases of allergic contact dermatitis, allergenic compounds in tea tree oil, practical patch testing information, and preventive measures.

  17. Tree Data (TD)

    Treesearch

    Robert E. Keane

    2006-01-01

    The Tree Data (TD) methods are used to sample individual live and dead trees on a fixed-area plot to estimate tree density, size, and age class distributions before and after fire in order to assess tree survival and mortality rates. This method can also be used to sample individual shrubs if they are over 4.5 ft tall. When trees are larger than the user-specified...

  18. There's Life in Hazard Trees

    Treesearch

    Mary Torsello; Toni McLellan

    The goals of hazard tree management programs are to maximize public safety and maintain a healthy sustainable tree resource. Although hazard tree management frequently targets removal of trees or parts of trees that attract wildlife, it can take into account a diversity of tree values. With just a little extra planning, hazard tree management can be highly beneficial...

  19. Fault-Tree Compiler

    NASA Technical Reports Server (NTRS)

    Butler, Ricky W.; Boerschlein, David P.

    1993-01-01

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

  20. Categorizing Ideas about Trees: A Tree of Trees

    PubMed Central

    Fisler, Marie; Lecointre, Guillaume

    2013-01-01

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

  1. Tree Classification Software

    NASA Technical Reports Server (NTRS)

    Buntine, Wray

    1993-01-01

    This paper introduces the IND Tree Package to prospective users. IND does supervised learning using classification trees. This learning task is a basic tool used in the development of diagnosis, monitoring and expert systems. The IND Tree Package was developed as part of a NASA project to semi-automate the development of data analysis and modelling algorithms using artificial intelligence techniques. The IND Tree Package integrates features from CART and C4 with newer Bayesian and minimum encoding methods for growing classification trees and graphs. The IND Tree Package also provides an experimental control suite on top. The newer features give improved probability estimates often required in diagnostic and screening tasks. The package comes with a manual, Unix 'man' entries, and a guide to tree methods and research. The IND Tree Package is implemented in C under Unix and was beta-tested at university and commercial research laboratories in the United States.

  2. Evolution of tree nutrition.

    PubMed

    Raven, John A; Andrews, Mitchell

    2010-09-01

    Using a broad definition of trees, the evolutionary origins of trees in a nutritional context is considered using data from the fossil record and molecular phylogeny. Trees are first known from the Late Devonian about 380 million years ago, originated polyphyletically at the pteridophyte grade of organization; the earliest gymnosperms were trees, and trees are polyphyletic in the angiosperms. Nutrient transporters, assimilatory pathways, homoiohydry (cuticle, intercellular gas spaces, stomata, endohydric water transport systems including xylem and phloem-like tissue) and arbuscular mycorrhizas preceded the origin of trees. Nutritional innovations that began uniquely in trees were the seed habit and, certainly (but not necessarily uniquely) in trees, ectomycorrhizas, cyanobacterial, actinorhizal and rhizobial (Parasponia, some legumes) diazotrophic symbioses and cluster roots.

  3. Rx for wounded trees

    Treesearch

    Hal Marx

    1976-01-01

    This booklet offers guidelines on how to care for trees to keep them healthy and to protect them from wounds. It also prescribes ways to prevent, recognize, and minimize damage by decay that most often sets in after tree wounding.

  4. Minnesota's Forest Trees. Revised.

    ERIC Educational Resources Information Center

    Miles, William R.; Fuller, Bruce L.

    This bulletin describes 46 of the more common trees found in Minnesota's forests and windbreaks. The bulletin contains two tree keys, a summer key and a winter key, to help the reader identify these trees. Besides the two keys, the bulletin includes an introduction, instructions for key use, illustrations of leaf characteristics and twig…

  5. Illumination Under Trees

    SciTech Connect

    Max, N

    2002-08-19

    This paper is a survey of the author's work on illumination and shadows under trees, including the effects of sky illumination, sun penumbras, scattering in a misty atmosphere below the trees, and multiple scattering and transmission between leaves. It also describes a hierarchical image-based rendering method for trees.

  6. Winter Birch Trees

    ERIC Educational Resources Information Center

    Sweeney, Debra; Rounds, Judy

    2011-01-01

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

  7. Decoding tree DNA

    Treesearch

    M. Thompson Conkle

    1986-01-01

    Check the laboratory reports after your next physical. You'll find information on a number of biochemical processes. Procedures like those used in the medical sciences are yielding valuable information about genetic differences among trees and tree pests. New procedures that provide ways to isolate and move genes are advancing progress in tree improvement. These...

  8. Diary of a Tree.

    ERIC Educational Resources Information Center

    Srulowitz, Frances

    1992-01-01

    Describes an activity to develop students' skills of observation and recordkeeping by studying the growth of a tree's leaves during the spring. Children monitor the growth of 11 tress over a 2-month period, draw pictures of the tree at different stages of growth, and write diaries of the tree's growth. (MDH)

  9. The Wish Tree Project

    ERIC Educational Resources Information Center

    Brooks, Sarah DeWitt

    2010-01-01

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

  10. The Wish Tree Project

    ERIC Educational Resources Information Center

    Brooks, Sarah DeWitt

    2010-01-01

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

  11. Winter Birch Trees

    ERIC Educational Resources Information Center

    Sweeney, Debra; Rounds, Judy

    2011-01-01

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

  12. Distributed Contour Trees

    SciTech Connect

    Morozov, Dmitriy; Weber, Gunther H.

    2014-03-31

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

  13. Growth of a Pine Tree

    ERIC Educational Resources Information Center

    Rollinson, Susan Wells

    2012-01-01

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

  14. Growth of a Pine Tree

    ERIC Educational Resources Information Center

    Rollinson, Susan Wells

    2012-01-01

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

  15. Dependency Tree Annotation Software

    DTIC Science & Technology

    2015-11-01

    This report presents Dependency Tree Editor (DTE), a software system built as part of a Science and Engineering Apprentice Program (SEAP) summer...internship. The system supports interactive visualization and editing of dependency trees ???a formalism frequently used in computational linguistics to...formats, and it provides numerous options for customizing how dependency trees are displayed. Built entirely in Java, it can run on a wide range of platforms.

  16. Tree genetics and improvement

    SciTech Connect

    Bey, C.F.; Houston, D.B.; Dinus, R.J.

    1986-01-01

    Tree improvement is a complex science and a multifaceted art. Tree improvement is most valuable when integrated within land-management programs. Major efforts are currently geared to developing improved seed for reforestation programs. Progeny testing is now a routine part of tree-improvement programs. Topics such as advanced-generation breeding, shortened generations, resistance breeding, and control of cone and seed insects are being given priority. Activity continues in basic research, involving genetic engineering, tissue culture, and population theory.

  17. Modeling individual tree survial

    Treesearch

    Quang V. Cao

    2016-01-01

    Information provided by growth and yield models is the basis for forest managers to make decisions on how to manage their forests. Among different types of growth models, whole-stand models offer predictions at stand level, whereas individual-tree models give detailed information at tree level. The well-known logistic regression is commonly used to predict tree...

  18. arb_tree_32

    SciTech Connect

    Bavykin, Sergey; Alferov, Oleg

    2006-08-01

    The purpose of this program is to generate probes specific for the group of sequences that belong to a given phylogenetic node. For each node of the input tree, this program selects probes that are positive for all sequences that belong to this node and negative for all that doesn't. The program uses condensed tree for probe representation to save computer memory. As a result of calculation, the program prints lists for each node from the tree. Input file formats: FASTA for sequence database and ARB tree for phylogenetic organization of nodes. Output file format: text file.

  19. Fragmentation of random trees

    NASA Astrophysics Data System (ADS)

    Kalay, Ziya; Ben-Naim, Eli

    2015-03-01

    We investigate the fragmentation of a random recursive tree by repeated removal of nodes, resulting in a forest of disjoint trees. The initial tree is generated by sequentially attaching new nodes to randomly chosen existing nodes until the tree contains N nodes. As nodes are removed, one at a time, the tree dissolves into an ensemble of separate trees, namely a forest. We study the statistical properties of trees and nodes in this heterogeneous forest. In the limit N --> ∞ , we find that the system is characterized by a single parameter: the fraction of remaining nodes m. We obtain analytically the size density ϕs of trees of size s, which has a power-law tail ϕs ~s-α , with exponent α = 1 + 1 / m . Therefore, the tail becomes steeper as further nodes are removed, producing an unusual scaling exponent that increases continuously with time. Furthermore, we investigate the fragment size distribution in a growing tree, where nodes are added as well as removed, and find that the distribution for this case is much narrower.

  20. Species integrity in trees.

    PubMed

    Ortiz-Barrientos, Daniel; Baack, Eric J

    2014-09-01

    From California sequoia, to Australian eucalyptus, to the outstanding diversity of Amazonian forests, trees are fundamental to many processes in ecology and evolution. Trees define the communities that they inhabit, are host to a multiplicity of other organisms and can determine the ecological dynamics of other plants and animals. Trees are also at the heart of major patterns of biodiversity such as the latitudinal gradient of species diversity and thus are important systems for studying the origin of new plant species. Although the role of trees in community assembly and ecological succession is partially understood, the origin of tree diversity remains largely opaque. For instance, the relative importance of differing habitats and phenologies as barriers to hybridization between closely related species is still largely uncharacterized in trees. Consequently, we know very little about the origin of trees species and their integrity. Similarly, studies on the interplay between speciation and tree community assembly are in their infancy and so are studies on how processes like forest maturation modifies the context in which reproductive isolation evolves. In this issue of Molecular Ecology, Lindtke et al. (2014) and Lagache et al. (2014) overcome some traditional difficulties in studying mating systems and sexual isolation in the iconic oaks and poplars, providing novel insights about the integrity of tree species and on how ecology leads to variation in selection on reproductive isolation over time and space. © 2014 John Wiley & Sons Ltd.

  1. Quantum decision tree classifier

    NASA Astrophysics Data System (ADS)

    Lu, Songfeng; Braunstein, Samuel L.

    2013-11-01

    We study the quantum version of a decision tree classifier to fill the gap between quantum computation and machine learning. The quantum entropy impurity criterion which is used to determine which node should be split is presented in the paper. By using the quantum fidelity measure between two quantum states, we cluster the training data into subclasses so that the quantum decision tree can manipulate quantum states. We also propose algorithms constructing the quantum decision tree and searching for a target class over the tree for a new quantum object.

  2. Are trees long-lived?

    Treesearch

    Kevin T. Smith

    2009-01-01

    Trees and tree care can capture the best of people's motivations and intentions. Trees are living memorials that help communities heal at sites of national tragedy, such as Oklahoma City and the World Trade Center. We mark the places of important historical events by the trees that grew nearby even if the original tree, such as the Charter Oak in Connecticut or...

  3. TreeCmp: Comparison of Trees in Polynomial Time

    PubMed Central

    Bogdanowicz, Damian; Giaro, Krzysztof; Wróbel, Borys

    2012-01-01

    When a phylogenetic reconstruction does not result in one tree but in several, tree metrics permit finding out how far the reconstructed trees are from one another. They also permit to assess the accuracy of a reconstruction if a true tree is known. TreeCmp implements eight metrics that can be calculated in polynomial time for arbitrary (not only bifurcating) trees: four for unrooted (Matching Split metric, which we have recently proposed, Robinson-Foulds, Path Difference, Quartet) and four for rooted trees (Matching Cluster, Robinson-Foulds cluster, Nodal Splitted and Triple). TreeCmp is the first implementation of Matching Split/Cluster metrics and the first efficient and convenient implementation of Nodal Splitted. It allows to compare relatively large trees. We provide an example of the application of TreeCmp to compare the accuracy of ten approaches to phylogenetic reconstruction with trees up to 5000 external nodes, using a measure of accuracy based on normalized similarity between trees.

  4. Trees in Our Lives.

    ERIC Educational Resources Information Center

    NatureScope, 1986

    1986-01-01

    Provides: (1) background information on how trees have influenced human history and how trees affect people today; (2) four activities dealing with these topics; and (3) a ready-to-copy page related to paper and plastics. Activities include an objective, recommended age level(s), subject area(s), list of materials needed, and procedures. (JN)

  5. Tree nut oils

    USDA-ARS?s Scientific Manuscript database

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

  6. Structural Equation Model Trees

    ERIC Educational Resources Information Center

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

    2013-01-01

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

  7. The tree BVOC index

    Treesearch

    J.R. Simpson; E.G. McPherson

    2011-01-01

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

  8. Fragmentation of random trees

    NASA Astrophysics Data System (ADS)

    Kalay, Z.; Ben-Naim, E.

    2015-01-01

    We study fragmentation of a random recursive tree into a forest by repeated removal of nodes. The initial tree consists of N nodes and it is generated by sequential addition of nodes with each new node attaching to a randomly-selected existing node. As nodes are removed from the tree, one at a time, the tree dissolves into an ensemble of separate trees, namely, a forest. We study statistical properties of trees and nodes in this heterogeneous forest, and find that the fraction of remaining nodes m characterizes the system in the limit N\\to ∞ . We obtain analytically the size density {{φ }s} of trees of size s. The size density has power-law tail {{φ }s}˜ {{s}-α } with exponent α =1+\\frac{1}{m}. Therefore, the tail becomes steeper as further nodes are removed, and the fragmentation process is unusual in that exponent α increases continuously with time. We also extend our analysis to the case where nodes are added as well as removed, and obtain the asymptotic size density for growing trees.

  9. A tree hurts, too

    Treesearch

    Northeastern Forest Experiment Station

    1973-01-01

    This booklet outlines what happens most of the time as decay develops in a living tree. The drawings are designed to give an accurate general presentation of the decay process by focusing only on the major portions of an extremely complex process that involves the interactions among microorganisms, environmental factors, and the tree. The better we understand these...

  10. TRANSPLANTING SHADE TREES.

    ERIC Educational Resources Information Center

    Illinois Univ., Urbana. Coll. of Agriculture.

    THIS RESOURCE MATERIAL FOR USE IN HIGH SCHOOL VOCATIONAL AGRICULTURE AND ADULT FARMER CLASSES WAS DESIGNED BY SUBJECT MATTER SPECIALISTS, TEACHER EDUCATORS, SUPERVISORS, AND TEACHERS. THE OBJECTIVE IS TO HELP SOLVE PROBLEMS IN TRANSPLANTING SHADE TREES. THE MAJOR SECTION TITLES ARE STATED AS PROBLEMS -- (1) HOW SHOULD I PREPARE A TREE FOR MOVING,…

  11. Moon tree ceremony

    NASA Image and Video Library

    2011-02-03

    Apollo 13 astronaut Fred Haise stands with Rosemary Roosa, daughter of late Apollo 14 astronaut Stuart Roosa, beside a 'moon tree' planted at the INFINITY science center on Feb. 3, 2011. The moon tree is a descendent of seeds carried into space by Stuart Roosa on the Apollo 14 mission in 1971.

  12. Reclamation: what about trees

    SciTech Connect

    Kolar, C.A.; Ashby, W.C.

    1982-07-01

    A five-year research programme was started in 1978 in the Botany Department of Southern Illinois University to evaluate the effect of reclamation practices on tree survival and growth. The project was initiated as a direct result of reports from Illinois and Indiana of tree-planting failures on mined lands reclaimed to current regulation standards.

  13. The Flame Tree

    ERIC Educational Resources Information Center

    Lewis, Richard

    2004-01-01

    Lewis's own experiences living in Indonesia are fertile ground for telling "a ripping good story," one found in "The Flame Tree." He hopes people will enjoy the tale and appreciate the differences of an unfamiliar culture. The excerpt from "The Flame Tree" will reel readers in quickly.

  14. Trees in Our Lives.

    ERIC Educational Resources Information Center

    NatureScope, 1986

    1986-01-01

    Provides: (1) background information on how trees have influenced human history and how trees affect people today; (2) four activities dealing with these topics; and (3) a ready-to-copy page related to paper and plastics. Activities include an objective, recommended age level(s), subject area(s), list of materials needed, and procedures. (JN)

  15. Trees Are Terrific!

    ERIC Educational Resources Information Center

    Braus, Judy, Ed.

    1992-01-01

    Ranger Rick's NatureScope is a creative education series dedicated to inspiring in children an understanding and appreciation of the natural world while developing the skills they will need to make responsible decisions about the environment. Contents are organized into the following sections: (1) "What Makes a Tree a Tree?," including…

  16. Tree planting in reclamation

    Treesearch

    Glen G. Kizer

    1980-01-01

    While fifteen years ago we depended on trees as the primary tool of reclamation, today regulators, based on soil loss studies, have determined that trees are not sufficient to prevent erosion by themselves. This is particularly true during the first 10-15 years after mining. While ten (10) years ago most permits listed forest as a postmining land use, today only ten (...

  17. Trees Are Terrific!

    ERIC Educational Resources Information Center

    Braus, Judy, Ed.

    1992-01-01

    Ranger Rick's NatureScope is a creative education series dedicated to inspiring in children an understanding and appreciation of the natural world while developing the skills they will need to make responsible decisions about the environment. Contents are organized into the following sections: (1) "What Makes a Tree a Tree?," including…

  18. Tree Topology Estimation.

    PubMed

    Estrada, Rolando; Tomasi, Carlo; Schmidler, Scott C; Farsiu, Sina

    2015-08-01

    Tree-like structures are fundamental in nature, and it is often useful to reconstruct the topology of a tree - what connects to what - from a two-dimensional image of it. However, the projected branches often cross in the image: the tree projects to a planar graph, and the inverse problem of reconstructing the topology of the tree from that of the graph is ill-posed. We regularize this problem with a generative, parametric tree-growth model. Under this model, reconstruction is possible in linear time if one knows the direction of each edge in the graph - which edge endpoint is closer to the root of the tree - but becomes NP-hard if the directions are not known. For the latter case, we present a heuristic search algorithm to estimate the most likely topology of a rooted, three-dimensional tree from a single two-dimensional image. Experimental results on retinal vessel, plant root, and synthetic tree data sets show that our methodology is both accurate and efficient.

  19. Structural Equation Model Trees

    ERIC Educational Resources Information Center

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

    2013-01-01

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

  20. Grading hardwood trees

    Treesearch

    Robert L. Brisbin

    1989-01-01

    Tree grading provides a way to evaluate the quality characteristics and value of standing hardwood trees. This is important because the differences in price between high-quality and low-quality end products can be very large. Since hardwood timber varies greatly in quality and value among species, within species, and even within specific geographic areas, timber...

  1. Tree biology and dendrochemistry

    Treesearch

    Kevin T. Smith; Walter C. Shortle

    1996-01-01

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

  2. CSI for Trees

    ERIC Educational Resources Information Center

    Rubino, Darrin L.; Hanson, Deborah

    2009-01-01

    The circles and patterns in a tree's stem tell a story, but that story can be a mystery. Interpreting the story of tree rings provides a way to heighten the natural curiosity of students and help them gain insight into the interaction of elements in the environment. It also represents a wonderful opportunity to incorporate the nature of science.…

  3. Individual tree control

    Treesearch

    Harvey A. Holt

    1989-01-01

    Controlling individual unwanted trees in forest stands is a readily accepted method for improving the value of future harvests. The practice is especially important in mixed hardwood forests where species differ considerably in value and within species individual trees differ in quality. Individual stem control is a mechanical or chemical weeding operation that...

  4. CSI for Trees

    ERIC Educational Resources Information Center

    Rubino, Darrin L.; Hanson, Deborah

    2009-01-01

    The circles and patterns in a tree's stem tell a story, but that story can be a mystery. Interpreting the story of tree rings provides a way to heighten the natural curiosity of students and help them gain insight into the interaction of elements in the environment. It also represents a wonderful opportunity to incorporate the nature of science.…

  5. Growing Up a Tree.

    ERIC Educational Resources Information Center

    NatureScope, 1986

    1986-01-01

    Provides: (1) background information on how trees reproduce, what they need to survive, and where they grow; (2) six activities dealing with these topics; and (3) a ready-to-copy page showing trees around the world. Each activity includes an objective, recommended age level(s), subject area(s), list of materials needed, and procedures. (JN)

  6. Trees for Mother Earth.

    ERIC Educational Resources Information Center

    Greer, Sandy

    1993-01-01

    Describes Trees for Mother Earth, a program in which secondary students raise funds to buy fruit trees to plant during visits to the Navajo Reservation. Benefits include developing feelings of self-worth among participants, promoting cultural exchange and understanding, and encouraging self-sufficiency among the Navajo. (LP)

  7. California tree seed zones

    Treesearch

    John M. Buck; Ronald S. Adams; Jerrold Cone; M. Thompson Conkle; William J. Libby; Cecil J. Eden; Michel J. Knight

    1970-01-01

    California forest tree seed zones were established originally by Fowells (1946), with revisions proposed by Roy (1963) and Schubert (1966). The Forest Tree Seed Committee of the Northern California Section, Society of American Foresters, has revised the original zones and updated the recording system described in the earlier reports. Fowells' (1946) Research Note...

  8. Tree growth visualization

    Treesearch

    L. Linsen; B.J. Karis; E.G. McPherson; B. Hamann

    2005-01-01

    In computer graphics, models describing the fractal branching structure of trees typically exploit the modularity of tree structures. The models are based on local production rules, which are applied iteratively and simultaneously to create a complex branching system. The objective is to generate three-dimensional scenes of often many realistic- looking and non-...

  9. Project Learning Tree (Corporate Propaganda Tree).

    ERIC Educational Resources Information Center

    Mayer, Mike

    This document contains a critical analysis of Project Learning Tree (PLT). PLT was developed and distributed in the mid-1970s. It consists of 2 activity guides, one for grades K-6 with 89 activities and another for grades 7-12 with 88 activities. The program also provides free workshops for teachers and others. The analysis of PLT includes the…

  10. From Family Trees to Decision Trees.

    ERIC Educational Resources Information Center

    Trobian, Helen R.

    This paper is a preliminary inquiry by a non-mathematician into graphic methods of sequential planning and ways in which hierarchical analysis and tree structures can be helpful in developing interest in the use of mathematical modeling in the search for creative solutions to real-life problems. Highlights include a discussion of hierarchical…

  11. Tree planters notes. Volume 43, Number 3, Summer 1992. Quarterly report

    SciTech Connect

    Mangold, R.; Nisley, R.; Karrfalt, R.; Landis, T.; Lantz, C.

    1992-01-01

    Contents: survival and growth of planted alaska-cedar seedling in southeast southeast alaska; propagation of loblolly, slash, and longleaf pine from needle fascicles; moisture determination on seeds of honeylocust and mimosa; performance of himalayan blue pine in the northeastern united states; advantages of an effective weed control program for populus hybrids; pales weevil: a serious threat to longleaf pine production; costs and cost component trends of trends of hand and machine planting in the southern united states (1952 to 1990); comparison of a drill-type seeder and a vacuum-drum precision seeder in a virginia loblolly pine nursery; missoula technology and development center's nursery and reforestation programs.

  12. Lazy decision trees

    SciTech Connect

    Friedman, J.H.; Yun, Yeogirl; Kohavi, R.

    1996-12-31

    Lazy learning algorithms, exemplified by nearest-neighbor algorithms, do not induce a concise hypothesis from a given training set; the inductive process is delayed until a test instance is given. Algorithms for constructing decision trees, such as C4.5, ID3, and CART create a single {open_quotes}best{close_quotes} decision tree during the training phase, and this tree is then used to classify test instances. The tests at the nodes of the constructed tree are good on average, but there may be better tests for classifying a specific instance. We propose a lazy decision tree algorithm-LazyDT-that conceptually constructs the {open_quotes}best{close_quote} decision tree for each test instance. In practice, only a path needs to be constructed, and a caching scheme makes the algorithm fast. The algorithm is robust with respect to missing values without resorting to the complicated methods usually seen in induction of decision trees. Experiments on real and artificial problems are presented.

  13. Phylogenetic trees in bioinformatics

    SciTech Connect

    Burr, Tom L

    2008-01-01

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

  14. Fragmentation trees reloaded.

    PubMed

    Böcker, Sebastian; Dührkop, Kai

    2016-01-01

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

  15. The gravity apple tree

    NASA Astrophysics Data System (ADS)

    Espinosa Aldama, Mariana

    2015-04-01

    The gravity apple tree is a genealogical tree of the gravitation theories developed during the past century. The graphic representation is full of information such as guides in heuristic principles, names of main proponents, dates and references for original articles (See under Supplementary Data for the graphic representation). This visual presentation and its particular classification allows a quick synthetic view for a plurality of theories, many of them well validated in the Solar System domain. Its diachronic structure organizes information in a shape of a tree following similarities through a formal concept analysis. It can be used for educational purposes or as a tool for philosophical discussion.

  16. Learning classification trees

    NASA Technical Reports Server (NTRS)

    Buntine, Wray

    1991-01-01

    Algorithms for learning classification trees have had successes in artificial intelligence and statistics over many years. How a tree learning algorithm can be derived from Bayesian decision theory is outlined. This introduces Bayesian techniques for splitting, smoothing, and tree averaging. The splitting rule turns out to be similar to Quinlan's information gain splitting rule, while smoothing and averaging replace pruning. Comparative experiments with reimplementations of a minimum encoding approach, Quinlan's C4 and Breiman et al. Cart show the full Bayesian algorithm is consistently as good, or more accurate than these other approaches though at a computational price.

  17. Evolutionary tree reconstruction

    NASA Technical Reports Server (NTRS)

    Cheeseman, Peter; Kanefsky, Bob

    1990-01-01

    It is described how Minimum Description Length (MDL) can be applied to the problem of DNA and protein evolutionary tree reconstruction. If there is a set of mutations that transform a common ancestor into a set of the known sequences, and this description is shorter than the information to encode the known sequences directly, then strong evidence for an evolutionary relationship has been found. A heuristic algorithm is described that searches for the simplest tree (smallest MDL) that finds close to optimal trees on the test data. Various ways of extending the MDL theory to more complex evolutionary relationships are discussed.

  18. Trees of trees: an approach to comparing multiple alternative phylogenies.

    PubMed

    Nye, Tom M W

    2008-10-01

    Phylogenetic analysis very commonly produces several alternative trees for a given fixed set of taxa. For example, different sets of orthologous genes may be analyzed, or the analysis may sample from a distribution of probable trees. This article describes an approach to comparing and visualizing multiple alternative phylogenies via the idea of a "tree of trees" or "meta-tree." A meta-tree clusters phylogenies with similar topologies together in the same way that a phylogeny clusters species with similar DNA sequences. Leaf nodes on a meta-tree correspond to the original set of phylogenies given by some analysis, whereas interior nodes correspond to certain consensus topologies. The construction of meta-trees is motivated by analogy with construction of a most parsimonious tree for DNA data, but instead of using DNA letters, in a meta-tree the characters are partitions or splits of the set of taxa. An efficient algorithm for meta-tree construction is described that makes use of a known relationship between the majority consensus and parsimony in terms of gain and loss of splits. To illustrate these ideas meta-trees are constructed for two datasets: a set of gene trees for species of yeast and trees from a bootstrap analysis of a set of gene trees in ray-finned fish. A software tool for constructing meta-trees and comparing alternative phylogenies is available online, and the source code can be obtained from the author.

  19. Tree-bank grammars

    SciTech Connect

    Charniak, E.

    1996-12-31

    By a {open_quotes}tree-bank grammar{close_quotes} we mean a context-free grammar created by reading the production rules directly from hand-parsed sentences in a tree bank. Common wisdom has it that such grammars do not perform well, though we know of no published data on the issue. The primary purpose of this paper is to show that the common wisdom is wrong. In particular, we present results on a tree-bank grammar based on the Penn Wall Street Journal tree bank. To the best of our knowledge, this grammar outperforms all other non-word-based statistical parsers/grammars on this corpus. That is, it outperforms parsers that consider the input as a string of tags and ignore the actual words of the corpus.

  20. Leonardo's Tree Theory.

    ERIC Educational Resources Information Center

    Werner, Suzanne K.

    2003-01-01

    Describes a series of activities exploring Leonardo da Vinci's tree theory that are designed to strengthen 8th grade students' data collection and problem solving skills in physical science classes. (KHR)

  1. Leonardo's Tree Theory.

    ERIC Educational Resources Information Center

    Werner, Suzanne K.

    2003-01-01

    Describes a series of activities exploring Leonardo da Vinci's tree theory that are designed to strengthen 8th grade students' data collection and problem solving skills in physical science classes. (KHR)

  2. Tea tree oil.

    PubMed

    Larson, David; Jacob, Sharon E

    2012-01-01

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

  3. Structural Equation Model Trees

    PubMed Central

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

    2015-01-01

    In the behavioral and social sciences, structural equation models (SEMs) have become widely accepted as a modeling tool for the relation between latent and observed variables. SEMs can be seen as a unification of several multivariate analysis techniques. SEM Trees combine the strengths of SEMs and the decision tree paradigm by building tree structures that separate a data set recursively into subsets with significantly different parameter estimates in a SEM. SEM Trees provide means for finding covariates and covariate interactions that predict differences in structural parameters in observed as well as in latent space and facilitate theory-guided exploration of empirical data. We describe the methodology, discuss theoretical and practical implications, and demonstrate applications to a factor model and a linear growth curve model. PMID:22984789

  4. Generalized constructive tree weights

    SciTech Connect

    Rivasseau, Vincent E-mail: adrian.tanasa@ens-lyon.org; Tanasa, Adrian E-mail: adrian.tanasa@ens-lyon.org

    2014-04-15

    The Loop Vertex Expansion (LVE) is a quantum field theory (QFT) method which explicitly computes the Borel sum of Feynman perturbation series. This LVE relies in a crucial way on symmetric tree weights which define a measure on the set of spanning trees of any connected graph. In this paper we generalize this method by defining new tree weights. They depend on the choice of a partition of a set of vertices of the graph, and when the partition is non-trivial, they are no longer symmetric under permutation of vertices. Nevertheless we prove they have the required positivity property to lead to a convergent LVE; in fact we formulate this positivity property precisely for the first time. Our generalized tree weights are inspired by the Brydges-Battle-Federbush work on cluster expansions and could be particularly suited to the computation of connected functions in QFT. Several concrete examples are explicitly given.

  5. Tree Topology Estimation

    PubMed Central

    Estrada, Rolando; Tomasi, Carlo; Schmidler, Scott C.; Farsiu, Sina

    2015-01-01

    Tree-like structures are fundamental in nature, and it is often useful to reconstruct the topology of a tree—what connects to what—from a two-dimensional image of it. However, the projected branches often cross in the image: the tree projects to a planar graph, and the inverse problem of reconstructing the topology of the tree from that of the graph is ill-posed. We regularize this problem with a generative, parametric tree-growth model. Under this model, reconstruction is possible in linear time if one knows the direction of each edge in the graph—which edge endpoint is closer to the root of the tree—but becomes NP-hard if the directions are not known. For the latter case, we present a heuristic search algorithm to estimate the most likely topology of a rooted, three-dimensional tree from a single two-dimensional image. Experimental results on retinal vessel, plant root, and synthetic tree datasets show that our methodology is both accurate and efficient. PMID:26353004

  6. Anatomy of the Pythagoras' Tree

    ERIC Educational Resources Information Center

    Teia, Luis

    2016-01-01

    The architecture of nature can be seen at play in a tree: no two are alike. The Pythagoras' tree behaves just as a "tree" in that the root plus the same movement repeated over and over again grows from a seed, to a plant, to a tree. In human life, this movement is termed cell division. With triples, this movement is a geometrical and…

  7. How Trees Can Save Energy.

    ERIC Educational Resources Information Center

    Fazio, James R., Ed.

    1991-01-01

    This document might easily have been called "How To Use Trees To Save Energy". It presents the energy saving advantages of landscaping the home and community with trees. The discussion includes: (1) landscaping advice to obtain the benefits of tree shade; (2) the heat island phenomenon in cities; (3) how and where to properly plant trees for…

  8. Anatomy of the Pythagoras' Tree

    ERIC Educational Resources Information Center

    Teia, Luis

    2016-01-01

    The architecture of nature can be seen at play in a tree: no two are alike. The Pythagoras' tree behaves just as a "tree" in that the root plus the same movement repeated over and over again grows from a seed, to a plant, to a tree. In human life, this movement is termed cell division. With triples, this movement is a geometrical and…

  9. Benefit-based tree valuation

    Treesearch

    E.G. McPherson

    2007-01-01

    Benefit-based tree valuation provides alternative estimates of the fair and reasonable value of trees while illustrating the relative contribution of different benefit types. This study compared estimates of tree value obtained using cost- and benefit-based approaches. The cost-based approach used the Council of Landscape and Tree Appraisers trunk formula method, and...

  10. State Trees and Arbor Days.

    ERIC Educational Resources Information Center

    Forest Service (USDA), Washington, DC.

    Provides information on state trees for each of the 50 states and the District of Columbia. Includes for each state: (1) year in which state tree was chosen; (2) common and scientific names of the tree; (3) arbor day observance; (4) address of state forester; and (5) drawings of the tree, leaf, and fruit or cone. (JN)

  11. Reinforcement Learning Trees.

    PubMed

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

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

  12. Reinforcement Learning Trees

    PubMed Central

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

    2015-01-01

    In this paper, we introduce a new type of tree-based method, reinforcement learning trees (RLT), which exhibits significantly improved performance over traditional methods such as random forests (Breiman, 2001) under high-dimensional settings. The innovations are three-fold. First, the new method implements reinforcement learning at each selection of a splitting variable during the tree construction processes. By splitting on the variable that brings the greatest future improvement in later splits, rather than choosing the one with largest marginal effect from the immediate split, the constructed tree utilizes the available samples in a more efficient way. Moreover, such an approach enables linear combination cuts at little extra computational cost. Second, we propose a variable muting procedure that progressively eliminates noise variables during the construction of each individual tree. The muting procedure also takes advantage of reinforcement learning and prevents noise variables from being considered in the search for splitting rules, so that towards terminal nodes, where the sample size is small, the splitting rules are still constructed from only strong variables. Last, we investigate asymptotic properties of the proposed method under basic assumptions and discuss rationale in general settings. PMID:26903687

  13. TreeFam: 2008 Update.

    PubMed

    Ruan, Jue; Li, Heng; Chen, Zhongzhong; Coghlan, Avril; Coin, Lachlan James M; Guo, Yiran; Hériché, Jean-Karim; Hu, Yafeng; Kristiansen, Karsten; Li, Ruiqiang; Liu, Tao; Moses, Alan; Qin, Junjie; Vang, Søren; Vilella, Albert J; Ureta-Vidal, Abel; Bolund, Lars; Wang, Jun; Durbin, Richard

    2008-01-01

    TreeFam (http://www.treefam.org) was developed to provide curated phylogenetic trees for all animal gene families, as well as orthologue and paralogue assignments. Release 4.0 of TreeFam contains curated trees for 1314 families and automatically generated trees for another 14,351 families. We have expanded TreeFam to include 25 fully sequenced animal genomes, as well as four genomes from plant and fungal outgroup species. We have also introduced more accurate approaches for automatically grouping genes into families, for building phylogenetic trees, and for inferring orthologues and paralogues. The user interface for viewing phylogenetic trees and family information has been improved. Furthermore, a new perl API lets users easily extract data from the TreeFam mysql database.

  14. ColorTree: a batch customization tool for phylogenic trees

    PubMed Central

    Chen, Wei-Hua; Lercher, Martin J

    2009-01-01

    Background Genome sequencing projects and comparative genomics studies typically aim to trace the evolutionary history of large gene sets, often requiring human inspection of hundreds of phylogenetic trees. If trees are checked for compatibility with an explicit null hypothesis (e.g., the monophyly of certain groups), this daunting task is greatly facilitated by an appropriate coloring scheme. Findings In this note, we introduce ColorTree, a simple yet powerful batch customization tool for phylogenic trees. Based on pattern matching rules, ColorTree applies a set of customizations to an input tree file, e.g., coloring labels or branches. The customized trees are saved to an output file, which can then be viewed and further edited by Dendroscope (a freely available tree viewer). ColorTree runs on any Perl installation as a stand-alone command line tool, and its application can thus be easily automated. This way, hundreds of phylogenic trees can be customized for easy visual inspection in a matter of minutes. Conclusion ColorTree allows efficient and flexible visual customization of large tree sets through the application of a user-supplied configuration file to multiple tree files. PMID:19646243

  15. ColorTree: a batch customization tool for phylogenic trees.

    PubMed

    Chen, Wei-Hua; Lercher, Martin J

    2009-07-31

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

  16. The gene tree delusion.

    PubMed

    Springer, Mark S; Gatesy, John

    2016-01-01

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

  17. A celestial Christmas tree

    NASA Astrophysics Data System (ADS)

    Moore, S.

    2006-12-01

    Having finished decorating your terrestrial Christmas tree this year, you may care to step outside and view a celestial one. Well placed in the December night sky in the often overlooked but very rewarding constellation of Monoceros, NGC 2264, called the Christmas Tree by the American astronomer and writer Leland S. Copeland, lies due south around 1 a.m. in mid-December at an altitude of 50°. The cluster lies amid a vast area of nebulosity, well captured in the image by Gordon Rogers on the cover of this Journal.

  18. The Inference of Gene Trees with Species Trees

    PubMed Central

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

    2015-01-01

    This article reviews the various models that have been used to describe the relationships between gene trees and species trees. Molecular phylogeny has focused mainly on improving models for the reconstruction of gene trees based on sequence alignments. Yet, most phylogeneticists seek to reveal the history of species. Although the histories of genes and species are tightly linked, they are seldom identical, because genes duplicate, are lost or horizontally transferred, and because alleles can coexist in populations for periods that may span several speciation events. Building models describing the relationship between gene and species trees can thus improve the reconstruction of gene trees when a species tree is known, and vice versa. Several approaches have been proposed to solve the problem in one direction or the other, but in general neither gene trees nor species trees are known. Only a few studies have attempted to jointly infer gene trees and species trees. These models account for gene duplication and loss, transfer or incomplete lineage sorting. Some of them consider several types of events together, but none exists currently that considers the full repertoire of processes that generate gene trees along the species tree. Simulations as well as empirical studies on genomic data show that combining gene tree–species tree models with models of sequence evolution improves gene tree reconstruction. In turn, these better gene trees provide a more reliable basis for studying genome evolution or reconstructing ancestral chromosomes and ancestral gene sequences. We predict that gene tree–species tree methods that can deal with genomic data sets will be instrumental to advancing our understanding of genomic evolution. PMID:25070970

  19. TreeDT: tree pattern mining for gene mapping.

    PubMed

    Sevon, Petteri; Toivonen, Hannu; Ollikainen, Vesa

    2006-01-01

    We describe TreeDT, a novel association-based gene mapping method. Given a set of disease-associated haplotypes and a set of control haplotypes, TreeDT predicts likely locations of a disease susceptibility gene. TreeDT extracts, essentially in the form of haplotype trees, information about historical recombinations in the population: A haplotype tree constructed at a given chromosomal location is an estimate of the genealogy of the haplotypes. TreeDT constructs these trees for all locations on the given haplotypes and performs a novel disequilibrium test on each tree: Is there a small set of subtrees with relatively high proportions of disease-associated chromosomes, suggesting shared genetic history for those and a likely disease gene location? We give a detailed description of TreeDT and the tree disequilibrium tests, we analyze the algorithm formally, and we evaluate its performance experimentally on both simulated and real data sets. Experimental results demonstrate that TreeDT has high accuracy on difficult mapping tasks and comparisons to other methods (EATDT, HPM, TDT) show that TreeDT is very competitive.

  20. Tree Modeling with Real Tree-Parts Examples.

    PubMed

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

    2016-12-01

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

  1. Phylogenics & Tree-Thinking

    ERIC Educational Resources Information Center

    Baum, David A.; Offner, Susan

    2008-01-01

    Phylogenetic trees, which are depictions of the inferred evolutionary relationships among a set of species, now permeate almost all branches of biology and are appearing in increasing numbers in biology textbooks. While few state standards explicitly require knowledge of phylogenetics, most require some knowledge of evolutionary biology, and many…

  2. Tree-Ties.

    ERIC Educational Resources Information Center

    Gresczyk, Rick

    Created to help students understand how plants were used for food, for medicine, and for arts and crafts among the Ojibwe (Chippewa) Indians, the game Tree-Ties combines earth and social sciences within a specific culture. The game requires mutual respect, understanding, and agreement to succeed. Sounding like the word "treaties", the…

  3. Tree-Ties.

    ERIC Educational Resources Information Center

    Gresczyk, Rick

    Created to help students understand how plants were used for food, for medicine, and for arts and crafts among the Ojibwe (Chippewa) Indians, the game Tree-Ties combines earth and social sciences within a specific culture. The game requires mutual respect, understanding, and agreement to succeed. Sounding like the word "treaties", the…

  4. How to Prune Trees

    Treesearch

    Peter Bedker; Joseph O' Brien; Manfred Mielke

    2012-01-01

    The objective of pruning is to produce strong, healthy, attractive plants. By understanding how, when and why to prune, and by following a few simple principles, this objective can be achievedHow to Prune Trees (Revised 2012) Agency Publisher: Agriculture Dept., Forest Service, Northeastern Area State and Price forestry USA List Price:$4.00 Sale...

  5. Digging Deeper with Trees.

    ERIC Educational Resources Information Center

    Growing Ideas, 2001

    2001-01-01

    Describes hands-on science areas that focus on trees. A project on leaf pigmentation involves putting crushed leaves in a test tube with solvent acetone to dissolve pigment. In another project, students learn taxonomy by sorting and classifying leaves based on observable characteristics. Includes a language arts connection. (PVD)

  6. Phylogenics & Tree-Thinking

    ERIC Educational Resources Information Center

    Baum, David A.; Offner, Susan

    2008-01-01

    Phylogenetic trees, which are depictions of the inferred evolutionary relationships among a set of species, now permeate almost all branches of biology and are appearing in increasing numbers in biology textbooks. While few state standards explicitly require knowledge of phylogenetics, most require some knowledge of evolutionary biology, and many…

  7. The Medicine Tree.

    ERIC Educational Resources Information Center

    Brokenleg, Martin

    2000-01-01

    Demographic changes in population continue to bring children of different cultural backgrounds to classrooms. This article provides suggestions teachers and counselors can use to bridge cultures. Using the parable of a medicine tree, it explains how no society can endure without caring for its young. (Author/JDM)

  8. Oak Tree Planting Project

    Treesearch

    Sherryl L. Nives; William D. Tietje; William H. Weitkamp

    1991-01-01

    An Oak Tree Planting Project was conducted during 1989/90 in San Luis Obispo County by the Integrated Hardwood Range Management Program (IHRMP)/Central Coast. The local media and an IHRMP workshop were used to publicize the Planting Project and give information on the status of oaks (Quercus spp.) in California and oak planting techniques. Outreach...

  9. Christmas Tree Category Manual.

    ERIC Educational Resources Information Center

    Bowman, James S.; Turmel, Jon P.

    This manual provides information needed to meet the standards for pesticide applicator certification. Pests and diseases of christmas tree plantations are identified and discussed. Section one deals with weeds and woody plants and the application, formulation and effects of herbicides in controlling them. Section two discusses specific diseases…

  10. Trees for Ohio

    Treesearch

    Ernest J. Gebhart

    1980-01-01

    Other members of this panel are going to reveal the basic statistics about the coal strip mining industry in Ohio so I will confine my remarks to the revegetation of the spoil banks. So it doesn't appear that Ohio confined its tree planting efforts to spoil banks alone, I will rely on a few statistics.

  11. Starting Trees from Cuttings.

    ERIC Educational Resources Information Center

    Kramer, David C.

    1983-01-01

    Describes a procedure for starting tree cuttings from woody plants, explaining "lag time," recommending materials, and giving step-by-step instructions for rooting and planting. Points out species which are likely candidates for cuttings and provides tips for teachers for developing a unit. (JM)

  12. A Universal Phylogenetic Tree.

    ERIC Educational Resources Information Center

    Offner, Susan

    2001-01-01

    Presents a universal phylogenetic tree suitable for use in high school and college-level biology classrooms. Illustrates the antiquity of life and that all life is related, even if it dates back 3.5 billion years. Reflects important evolutionary relationships and provides an exciting way to learn about the history of life. (SAH)

  13. Chapter 5 - Tree Mortality

    Treesearch

    Mark J. Ambrose

    2014-01-01

    Tree mortality is a natural process in all forest ecosystems. Extremely high mortality, however, can also be an indicator of forest health issues. On a regional scale, high mortality levels may indicate widespread insect or disease problems. High mortality may also occur if a large proportion of the forest in a particular region is made up of older, senescent stands....

  14. Christmas Tree Pest Manual

    Treesearch

    Department of Entomology Michigan State University

    1998-01-01

    This manual can help you identify and control damaging Christmas tree pests in the North Central region of the United States. Most of the information also applies to the northeastern states and to the southern portions of the Canadian Provinces that border these states. You do not have to be a pest specialist to use this information; we wrote the manual in everyday...

  15. Digging Deeper with Trees.

    ERIC Educational Resources Information Center

    Growing Ideas, 2001

    2001-01-01

    Describes hands-on science areas that focus on trees. A project on leaf pigmentation involves putting crushed leaves in a test tube with solvent acetone to dissolve pigment. In another project, students learn taxonomy by sorting and classifying leaves based on observable characteristics. Includes a language arts connection. (PVD)

  16. Christmas Tree Category Manual.

    ERIC Educational Resources Information Center

    Bowman, James S.; Turmel, Jon P.

    This manual provides information needed to meet the standards for pesticide applicator certification. Pests and diseases of christmas tree plantations are identified and discussed. Section one deals with weeds and woody plants and the application, formulation and effects of herbicides in controlling them. Section two discusses specific diseases…

  17. The Sacred Tree.

    ERIC Educational Resources Information Center

    Lethbridge Univ. (Alberta).

    Designed as a text for high school students and adults, this illustrated book presents ethical concepts and teachings of Native societies throughout North America concerning the nature and possibilities of human existence. The final component of a course in self-discovery and development, the book begins with the legend of the "Sacred Tree"…

  18. The tree alignment problem.

    PubMed

    Varón, Andrés; Wheeler, Ward C

    2012-11-09

    The inference of homologies among DNA sequences, that is, positions in multiple genomes that share a common evolutionary origin, is a crucial, yet difficult task facing biologists. Its computational counterpart is known as the multiple sequence alignment problem. There are various criteria and methods available to perform multiple sequence alignments, and among these, the minimization of the overall cost of the alignment on a phylogenetic tree is known in combinatorial optimization as the Tree Alignment Problem. This problem typically occurs as a subproblem of the Generalized Tree Alignment Problem, which looks for the tree with the lowest alignment cost among all possible trees. This is equivalent to the Maximum Parsimony problem when the input sequences are not aligned, that is, when phylogeny and alignments are simultaneously inferred. For large data sets, a popular heuristic is Direct Optimization (DO). DO provides a good tradeoff between speed, scalability, and competitive scores, and is implemented in the computer program POY. All other (competitive) algorithms have greater time complexities compared to DO. Here, we introduce and present experiments a new algorithm Affine-DO to accommodate the indel (alignment gap) models commonly used in phylogenetic analysis of molecular sequence data. Affine-DO has the same time complexity as DO, but is correctly suited for the affine gap edit distance. We demonstrate its performance with more than 330,000 experimental tests. These experiments show that the solutions of Affine-DO are close to the lower bound inferred from a linear programming solution. Moreover, iterating over a solution produced using Affine-DO shows little improvement. Our results show that Affine-DO is likely producing near-optimal solutions, with approximations within 10% for sequences with small divergence, and within 30% for random sequences, for which Affine-DO produced the worst solutions. The Affine-DO algorithm has the necessary scalability and

  19. The tree alignment problem

    PubMed Central

    2012-01-01

    Background The inference of homologies among DNA sequences, that is, positions in multiple genomes that share a common evolutionary origin, is a crucial, yet difficult task facing biologists. Its computational counterpart is known as the multiple sequence alignment problem. There are various criteria and methods available to perform multiple sequence alignments, and among these, the minimization of the overall cost of the alignment on a phylogenetic tree is known in combinatorial optimization as the Tree Alignment Problem. This problem typically occurs as a subproblem of the Generalized Tree Alignment Problem, which looks for the tree with the lowest alignment cost among all possible trees. This is equivalent to the Maximum Parsimony problem when the input sequences are not aligned, that is, when phylogeny and alignments are simultaneously inferred. Results For large data sets, a popular heuristic is Direct Optimization (DO). DO provides a good tradeoff between speed, scalability, and competitive scores, and is implemented in the computer program POY. All other (competitive) algorithms have greater time complexities compared to DO. Here, we introduce and present experiments a new algorithm Affine-DO to accommodate the indel (alignment gap) models commonly used in phylogenetic analysis of molecular sequence data. Affine-DO has the same time complexity as DO, but is correctly suited for the affine gap edit distance. We demonstrate its performance with more than 330,000 experimental tests. These experiments show that the solutions of Affine-DO are close to the lower bound inferred from a linear programming solution. Moreover, iterating over a solution produced using Affine-DO shows little improvement. Conclusions Our results show that Affine-DO is likely producing near-optimal solutions, with approximations within 10% for sequences with small divergence, and within 30% for random sequences, for which Affine-DO produced the worst solutions. The Affine-DO algorithm has

  20. New Life From Dead Trees

    ERIC Educational Resources Information Center

    DeGraaf, Richard M.

    1978-01-01

    There are numerous bird species that will nest only in dead or dying trees. Current forestry practices include clearing forests of these snags, or dead trees. This practice is driving many species out of the forests. An illustrated example of bird succession in and on a tree is given. (MA)

  1. Building up rhetorical structure trees

    SciTech Connect

    Marcu, D.

    1996-12-31

    I use the distinction between the nuclei and the satellites that pertain to discourse relations to introduce a compositionality criterion for discourse trees. I provide a first-order formalization of rhetorical structure trees and, on its basis, I derive an algorithm that constructs all the valid rhetorical trees that can be associated with a given discourse.

  2. Our Air: Unfit for Trees.

    ERIC Educational Resources Information Center

    Dochinger, Leon S.

    To help urban, suburban, and rural tree owners know about air pollution's effects on trees and their tolerance and intolerance to pollutants, the USDA Forest Service has prepared this booklet. It answers the following questions about atmospheric pollution: Where does it come from? What can it do to trees? and What can we do about it? In addition,…

  3. The Hopi Fruit Tree Book.

    ERIC Educational Resources Information Center

    Nyhuis, Jane

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

  4. The Hopi Fruit Tree Book.

    ERIC Educational Resources Information Center

    Nyhuis, Jane

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

  5. Our Air: Unfit for Trees.

    ERIC Educational Resources Information Center

    Dochinger, Leon S.

    To help urban, suburban, and rural tree owners know about air pollution's effects on trees and their tolerance and intolerance to pollutants, the USDA Forest Service has prepared this booklet. It answers the following questions about atmospheric pollution: Where does it come from? What can it do to trees? and What can we do about it? In addition,…

  6. The Tree Worker's Manual. [Revised.

    ERIC Educational Resources Information Center

    Lilly, S. J.

    This manual acquaints readers with the general operations of the tree care industry. The manual covers subjects important to a tree worker and serves as a training aid for workers at the entry level as tree care professionals. Each chapter begins with a set of objectives and may include figures, tables, and photographs. Ten chapters are included:…

  7. The Re-Think Tree.

    ERIC Educational Resources Information Center

    Gear, Jim

    1993-01-01

    The Re-Think Tree is a simple framework to help individuals assess and improve their behaviors related to environmental issues. The branches of the tree in order of priority are refuse, reduce, re-use, and recycle. Roots of the tree include such things as public opinion, education, and watchdog groups. (KS)

  8. Tree decay an expanded concept

    Treesearch

    Alex L. Shigo

    1979-01-01

    This publication is the final one in a series on tree decay developed in cooperation with Harold G. Marx, Research Application Staff Assistant, U.S. Department of Agriculture, Forest Service, Washington, D.C. The purpose of this publication is to clarify further the tree decay concept that expands the classical concept to include the orderly response of the tree to...

  9. The Re-Think Tree.

    ERIC Educational Resources Information Center

    Gear, Jim

    1993-01-01

    The Re-Think Tree is a simple framework to help individuals assess and improve their behaviors related to environmental issues. The branches of the tree in order of priority are refuse, reduce, re-use, and recycle. Roots of the tree include such things as public opinion, education, and watchdog groups. (KS)

  10. Inferences from growing trees backwards

    Treesearch

    David W. Green; Kent A. McDonald

    1997-01-01

    The objective of this paper is to illustrate how longitudinal stress wave techniques can be useful in tracking the future quality of a growing tree. Monitoring the quality of selected trees in a plantation forest could provide early input to decisions on the effectiveness of management practices, or future utilization options, for trees in a plantation. There will...

  11. New Life From Dead Trees

    ERIC Educational Resources Information Center

    DeGraaf, Richard M.

    1978-01-01

    There are numerous bird species that will nest only in dead or dying trees. Current forestry practices include clearing forests of these snags, or dead trees. This practice is driving many species out of the forests. An illustrated example of bird succession in and on a tree is given. (MA)

  12. Geometric tree kernels: classification of COPD from airway tree geometry.

    PubMed

    Feragen, Aasa; Petersen, Jens; Grimm, Dominik; Dirksen, Asger; Pedersen, Jesper Holst; Borgwardt, Karsten; de Bruijne, Marleen

    2013-01-01

    Methodological contributions: This paper introduces a family of kernels for analyzing (anatomical) trees endowed with vector valued measurements made along the tree. While state-of-the-art graph and tree kernels use combinatorial tree/graph structure with discrete node and edge labels, the kernels presented in this paper can include geometric information such as branch shape, branch radius or other vector valued properties. In addition to being flexible in their ability to model different types of attributes, the presented kernels are computationally efficient and some of them can easily be computed for large datasets (N - 10.000) of trees with 30 - 600 branches. Combining the kernels with standard machine learning tools enables us to analyze the relation between disease and anatomical tree structure and geometry. Experimental results: The kernels are used to compare airway trees segmented from low-dose CT, endowed with branch shape descriptors and airway wall area percentage measurements made along the tree. Using kernelized hypothesis testing we show that the geometric airway trees are significantly differently distributed in patients with Chronic Obstructive Pulmonary Disease (COPD) than in healthy individuals. The geometric tree kernels also give a significant increase in the classification accuracy of COPD from geometric tree structure endowed with airway wall thickness measurements in comparison with state-of-the-art methods, giving further insight into the relationship between airway wall thickness and COPD. Software: Software for computing kernels and statistical tests is available at http://image.diku.dk/aasa/software.php.

  13. Tree Colors: Color Schemes for Tree-Structured Data.

    PubMed

    Tennekes, Martijn; de Jonge, Edwin

    2014-12-01

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

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

    PubMed

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

    2014-03-06

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

  15. Fault-Tree Compiler Program

    NASA Technical Reports Server (NTRS)

    Butler, Ricky W.; Martensen, Anna L.

    1992-01-01

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

  16. Assessing urban forest effects and values: Douglas County, Kansas

    Treesearch

    David J. Nowak; Allison R. Bodine; Robert E. Hoehn; Alexis Ellis; Kim Bomberger; Daniel E. Crane; Theodore A. Endreny; Thomas Taggert; Emily. Stephan

    2014-01-01

    An analysis of trees in Douglas County, Kansas, reveals that this area has about 14,164,000 trees with tree and shrub canopy that covers 25.2 percent of the county. The most common tree species are American elm, northern hackberry, eastern redcedar, Osage-orange, and honeylocust. Trees in Douglas County currently store about 1.7 million tons of carbon (6.4 million tons...

  17. Assessing urban forest effects and values: the greater Kansas City region

    Treesearch

    David J. Nowak; Allison R. Bodine; Robert E. III Hoehn; Daniel E. Crane; Alexis Ellis; Theodore A. Endreny; Yang Yang; Tom Jacobs; Kassie. Shelton

    2013-01-01

    An analysis of trees in the greater Kansas City region of Missouri and Kansas reveals that this area has about 249,450,000 trees with tree and shrub canopy that covers 28.3 percent of the region. The most common tree species are American elm, northern hackberry, Osage-orange, honeylocust, and eastern redcedar. Trees in the greater Kansas City region currently store...

  18. Doubly robust survival trees.

    PubMed

    Steingrimsson, Jon Arni; Diao, Liqun; Molinaro, Annette M; Strawderman, Robert L

    2016-09-10

    Estimating a patient's mortality risk is important in making treatment decisions. Survival trees are a useful tool and employ recursive partitioning to separate patients into different risk groups. Existing 'loss based' recursive partitioning procedures that would be used in the absence of censoring have previously been extended to the setting of right censored outcomes using inverse probability censoring weighted estimators of loss functions. In this paper, we propose new 'doubly robust' extensions of these loss estimators motivated by semiparametric efficiency theory for missing data that better utilize available data. Simulations and a data analysis demonstrate strong performance of the doubly robust survival trees compared with previously used methods. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  19. Global Value Trees

    PubMed Central

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

    2015-01-01

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

  20. How To Write a Municipal Tree Ordinance.

    ERIC Educational Resources Information Center

    Fazio, James R., Ed.

    1990-01-01

    At the heart of the Tree City USA program are four basic requirements: The community must have the following: (1) a tree board or department; (2) an annual community forestry program with financial provisions for trees and tree care; (3) an annual Arbor Day proclamation and observance; and (4) a tree ordinance. Sections of a model tree ordinance…

  1. Tree Rings: Timekeepers of the Past.

    ERIC Educational Resources Information Center

    Phipps, R. L.; McGowan, J.

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

  2. Insert tree completion system

    SciTech Connect

    Brands, K.W.; Ball, I.G.; Cegielski, E.J.; Gresham, J.S.; Saunders, D.N.

    1982-09-01

    This paper outlines the overall project for development and installation of a low-profile, caisson-installed subsea Christmas tree. After various design studies and laboratory and field tests of key components, a system for installation inside a 30-in. conductor was ordered in July 1978 from Cameron Iron Works Inc. The system is designed to have all critical-pressure-containing components below the mudline and, with the reduced profile (height) above seabed, provides for improved safety of satellite underwater wells from damage by anchors, trawl boards, and even icebergs. In addition to the innovative nature of the tree design, the completion includes improved 3 1/2-in. through flowline (TFL) pumpdown completion equipment with deep set safety valves and a dual detachable packer head for simplified workover capability. The all-hydraulic control system incorporates a new design of sequencing valve for both Christmas tree control and remote flowline connection. A semisubmersible drilling rig was used to initiate the first end flowline connection at the wellhead for subsequent tie-in to the prelaid, surface-towed, all-welded subsea pipeline bundle.

  3. Active flows on trees

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

  4. Structural regression trees

    SciTech Connect

    Kramer, S.

    1996-12-31

    In many real-world domains the task of machine learning algorithms is to learn a theory for predicting numerical values. In particular several standard test domains used in Inductive Logic Programming (ILP) are concerned with predicting numerical values from examples and relational and mostly non-determinate background knowledge. However, so far no ILP algorithm except one can predict numbers and cope with nondeterminate background knowledge. (The only exception is a covering algorithm called FORS.) In this paper we present Structural Regression Trees (SRT), a new algorithm which can be applied to the above class of problems. SRT integrates the statistical method of regression trees into ILP. It constructs a tree containing a literal (an atomic formula or its negation) or a conjunction of literals in each node, and assigns a numerical value to each leaf. SRT provides more comprehensible results than purely statistical methods, and can be applied to a class of problems most other ILP systems cannot handle. Experiments in several real-world domains demonstrate that the approach is competitive with existing methods, indicating that the advantages are not at the expense of predictive accuracy.

  5. Tree nut allergens.

    PubMed

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

    2003-08-01

    Allergic reactions to tree nuts can be serious and life threatening. Considerable research has been conducted in recent years in an attempt to characterize those allergens that are most responsible for allergy sensitization and triggering. Both native and recombinant nut allergens have been identified and characterized and, for some, the IgE-reactive epitopes described. Some allergens, such as lipid transfer proteins, profilins, and members of the Bet v 1-related family, represent minor constituents in tree nuts. These allergens are frequently cross-reactive with other food and pollen homologues, and are considered panallergens. Others, such as legumins, vicilins, and 2S albumins, represent major seed storage protein constituents of the nuts. The allergenic tree nuts discussed in this review include those most commonly responsible for allergic reactions such as hazelnut, walnut, cashew, and almond as well as those less frequently associated with allergies including pecan, chestnut, Brazil nut, pine nut, macadamia nut, pistachio, coconut, Nangai nut, and acorn. Copyright 2003 S. Karger AG, Basel

  6. Exact solutions for species tree inference from discordant gene trees.

    PubMed

    Chang, Wen-Chieh; Górecki, Paweł; Eulenstein, Oliver

    2013-10-01

    Phylogenetic analysis has to overcome the grant challenge of inferring accurate species trees from evolutionary histories of gene families (gene trees) that are discordant with the species tree along whose branches they have evolved. Two well studied approaches to cope with this challenge are to solve either biologically informed gene tree parsimony (GTP) problems under gene duplication, gene loss, and deep coalescence, or the classic RF supertree problem that does not rely on any biological model. Despite the potential of these problems to infer credible species trees, they are NP-hard. Therefore, these problems are addressed by heuristics that typically lack any provable accuracy and precision. We describe fast dynamic programming algorithms that solve the GTP problems and the RF supertree problem exactly, and demonstrate that our algorithms can solve instances with data sets consisting of as many as 22 taxa. Extensions of our algorithms can also report the number of all optimal species trees, as well as the trees themselves. To better asses the quality of the resulting species trees that best fit the given gene trees, we also compute the worst case species trees, their numbers, and optimization score for each of the computational problems. Finally, we demonstrate the performance of our exact algorithms using empirical and simulated data sets, and analyze the quality of heuristic solutions for the studied problems by contrasting them with our exact solutions.

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

    USGS Publications Warehouse

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

    2014-01-01

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

  8. Trees in the city: valuing street trees in Portland, Oregon

    Treesearch

    G.H. Donovan; D.T. Butry

    2010-01-01

    We use a hedonic price model to simultaneously estimate the effects of street trees on the sales price and the time-on-market (TOM) of houses in Portland. Oregon. On average, street trees add $8,870 to sales price and reduce TOM by 1.7 days. In addition, we found that the benefits of street trees spill over to neighboring houses. Because the provision and maintenance...

  9. Fault Tree Handbook

    DTIC Science & Technology

    1981-01-01

    uat r CmIi S ft II >5±4"’’ NUREG-0492 Fault Tree Handbook Date Published: January 1981 W. E. Vesely, U.S. Nuclear Regulatory Commission F. F...Goldberg, U.S. Nuclear Regulatory Commission N. H. Roberts, University of Washington D. F. Haasl, Institute of System Sciences, Inc. Systems and...Reliability Research Office of Nuclear Regulatory Research U.S. Nuclear Regulatory Commission Washington, D.C. 20555 RG &,, ý0 For sale by the U.S

  10. Save a Tree

    NASA Astrophysics Data System (ADS)

    Williams, Kathryn R.

    1999-10-01

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

  11. Clustering with shallow trees

    NASA Astrophysics Data System (ADS)

    Bailly-Bechet, M.; Bradde, S.; Braunstein, A.; Flaxman, A.; Foini, L.; Zecchina, R.

    2009-12-01

    We propose a new method for obtaining hierarchical clustering based on the optimization of a cost function over trees of limited depth, and we derive a message-passing method that allows one to use it efficiently. The method and the associated algorithm can be interpreted as a natural interpolation between two well-known approaches, namely that of single linkage and the recently presented affinity propagation. We analyse using this general scheme three biological/medical structured data sets (human population based on genetic information, proteins based on sequences and verbal autopsies) and show that the interpolation technique provides new insight.

  12. Palm tree peroxidases.

    PubMed

    Sakharov, I Yu

    2004-08-01

    Over the years novel plant peroxidases have been isolated from palm trees leaves. Some molecular and catalytic properties of palm peroxidases have been studied. The substrate specificity of palm peroxidases is distinct from the specificity of other plant peroxidases. Palm peroxidases show extremely high stability under acidic and alkaline conditions and high thermal stability. Moreover, these enzymes are more stable with respect to hydrogen peroxide treatment than other peroxidases. Due to their extremely high stability, palm peroxidases have been used successfully in the development of new bioanalytical tests, the construction of improved biosensors, and in polymer synthesis.

  13. The fault-tree compiler

    NASA Technical Reports Server (NTRS)

    Martensen, Anna L.; Butler, Ricky W.

    1987-01-01

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

  14. Large Deviations for Random Trees

    PubMed Central

    Heitsch, Christine

    2010-01-01

    We consider large random trees under Gibbs distributions and prove a Large Deviation Principle (LDP) for the distribution of degrees of vertices of the tree. The LDP rate function is given explicitly. An immediate consequence is a Law of Large Numbers for the distribution of vertex degrees in a large random tree. Our motivation for this study comes from the analysis of RNA secondary structures. PMID:20216937

  15. Tree injuries from mechanized logging

    Treesearch

    Richard M. Godman

    1992-01-01

    Small trees in even-aged northern hardwood stands suffer the most mechanical damage when stands are thinned for the first time. From 15 to 35 percent of the trees may be damaged; a quarter of the trees (but usually less than 20 per acre) can be seriously damaged by having at least 50 square inches of the cambium exposed. Bole damage is most common, followed by root and...

  16. Compartmentalization of decay in trees

    Treesearch

    Alex L. Shigo

    1985-01-01

    Trees have a spectacular survival record. Over a period of more than 400 million years they have evolved as the tallest, most massive and longest-lived organisms ever to inhabit the earth. Yet trees lack a means of defense that almost every animal has: trees cannot move away from destructive forces. Because they cannot move, all types of living and nonliving enemies—...

  17. Barking up the Right Tree

    ERIC Educational Resources Information Center

    Houston, Paul D.

    2006-01-01

    There is a childhood saying about a confused dog who thinks he sees a possum in a tree. The problem is that the possum is actually in a different tree so the dog barks up the wrong tree. American education is constantly playing both dog and possum. Sometimes they are the prey, and sometimes they are just confused about what and where the prey is.…

  18. Inference of reversible tree languages.

    PubMed

    López, Damián; Sempere, José M; García, Pedro

    2004-08-01

    In this paper, we study the notion of k-reversibility and k-testability when regular tree languages are involved. We present an inference algorithm for learning a k-testable tree language that runs in polynomial time with respect to the size of the sample used. We also study the tree language classes in relation to other well known ones, and some properties of these languages are proven.

  19. Human decision error (HUMDEE) trees

    SciTech Connect

    Ostrom, L.T.

    1993-08-01

    Graphical presentations of human actions in incident and accident sequences have been used for many years. However, for the most part, human decision making has been underrepresented in these trees. This paper presents a method of incorporating the human decision process into graphical presentations of incident/accident sequences. This presentation is in the form of logic trees. These trees are called Human Decision Error Trees or HUMDEE for short. The primary benefit of HUMDEE trees is that they graphically illustrate what else the individuals involved in the event could have done to prevent either the initiation or continuation of the event. HUMDEE trees also present the alternate paths available at the operator decision points in the incident/accident sequence. This is different from the Technique for Human Error Rate Prediction (THERP) event trees. There are many uses of these trees. They can be used for incident/accident investigations to show what other courses of actions were available and for training operators. The trees also have a consequence component so that not only the decision can be explored, also the consequence of that decision.

  20. Phylogenetic trees and Euclidean embeddings.

    PubMed

    Layer, Mark; Rhodes, John A

    2017-01-01

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

  1. Distributed Merge Trees

    SciTech Connect

    Morozov, Dmitriy; Weber, Gunther

    2013-01-08

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

  2. Genealogy and gene trees.

    PubMed

    Rasmuson, Marianne

    2008-02-01

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

  3. Whole-tree canopy enclosures: why cage a tree?

    Treesearch

    Jerome F. Grant; Abdul Hakeem; Paris L. Lambdin; Gregory J. Wiggins; Rusty J. Rhea

    2011-01-01

    The use of whole-tree canopy enclosures (i.e., cages) is not a typical approach to assessing biological parameters and interactions in a forest setting. However, the successful application of this technology may enable researchers to better understand certain types of tree/organismal interactions.

  4. DIF Trees: Using Classification Trees to Detect Differential Item Functioning

    ERIC Educational Resources Information Center

    Vaughn, Brandon K.; Wang, Qiu

    2010-01-01

    A nonparametric tree classification procedure is used to detect differential item functioning for items that are dichotomously scored. Classification trees are shown to be an alternative procedure to detect differential item functioning other than the use of traditional Mantel-Haenszel and logistic regression analysis. A nonparametric…

  5. Relating phylogenetic trees to transmission trees of infectious disease outbreaks.

    PubMed

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

    2013-11-01

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

  6. DIF Trees: Using Classification Trees to Detect Differential Item Functioning

    ERIC Educational Resources Information Center

    Vaughn, Brandon K.; Wang, Qiu

    2010-01-01

    A nonparametric tree classification procedure is used to detect differential item functioning for items that are dichotomously scored. Classification trees are shown to be an alternative procedure to detect differential item functioning other than the use of traditional Mantel-Haenszel and logistic regression analysis. A nonparametric…

  7. TreeVector: scalable, interactive, phylogenetic trees for the web.

    PubMed

    Pethica, Ralph; Barker, Gary; Kovacs, Tim; Gough, Julian

    2010-01-28

    Phylogenetic trees are complex data forms that need to be graphically displayed to be human-readable. Traditional techniques of plotting phylogenetic trees focus on rendering a single static image, but increases in the production of biological data and large-scale analyses demand scalable, browsable, and interactive trees. We introduce TreeVector, a Scalable Vector Graphics-and Java-based method that allows trees to be integrated and viewed seamlessly in standard web browsers with no extra software required, and can be modified and linked using standard web technologies. There are now many bioinformatics servers and databases with a range of dynamic processes and updates to cope with the increasing volume of data. TreeVector is designed as a framework to integrate with these processes and produce user-customized phylogenies automatically. We also address the strengths of phylogenetic trees as part of a linked-in browsing process rather than an end graphic for print. TreeVector is fast and easy to use and is available to download precompiled, but is also open source. It can also be run from the web server listed below or the user's own web server. It has already been deployed on two recognized and widely used database Web sites.

  8. Trees of Yap: a field guide

    Treesearch

    Marjorie V. Cushing. Falanruw

    2015-01-01

    Descriptions, drawings, and photographs are presented for trees found on the Yap Islands in the Federated States of Micronesia. Included are all recorded native trees and most introduced trees as well as new records of native and introduced trees. Additional information is provided on tree distribution, status, vernacular names in Micronesia, and English names when...

  9. Urban tree database and allometric equations

    Treesearch

    E. Gregory McPherson; Natalie S. van Doorn; Paula J.  Peper

    2016-01-01

    Information on urban tree growth underpins models used to calculate the effects of trees on the environment and human well-being. Maximum tree size and other growth data are used by urban forest managers, landscape architects, and planners to select trees most suitable to the amount of growing space, thereby reducing costly future conflicts between trees and...

  10. Interim hardwood tree grades for factory lumber

    Treesearch

    Leland F. Hanks; Leland F. Hanks

    1971-01-01

    Hardwood trees have for many years been measured in such a way that tree volume could be estimated; and in recent years the prediction of tree quality by using tree grades has become of interest to owners, sellers, and buyers of timber. Several tree-grading systems have been developed, but none has been publicized and used on a widespread scale. The Forest Service...

  11. NE-TWIGS update: Incorporating tree quality

    Treesearch

    Daniel A. Yaussy

    1993-01-01

    A method to distribute tree quality was incorporated into the NE-TWIGS individual-tree growth and yield simulator. The program uses potential tree grade to allow changes in actual tree grade over time. Volume is reported by grade and value is calculated using tree grades. Example screens are shown.

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

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

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

  13. Better trees through systematic breeding

    Treesearch

    Robert Z. Callaham

    1957-01-01

    Today I would like to tell you briefly about the efforts of forest geneticists to improve the quality of forest trees. What do we mean by quality? Here, the consumer has the first word. The trees we produce are primarily for timber production, and the timber growing and wood-using industries give us our guidelines. Nevertheless, many of the characteristics sought by...

  14. Tree value system: users guide.

    Treesearch

    J.K. Ayer Sachet; D.G. Briggs; R.D. Fight

    1989-01-01

    This paper instructs resource analysts on use of the Tree Value System (TREEVAL). TREEVAL is a microcomputer system of programs for calculating tree or stand values and volumes based on predicted product recovery. Designed for analyzing silvicultural decisions, the system can also be used for appraisals and for evaluating log bucking. The system calculates results...

  15. Tree Hydraulics: How Sap Rises

    ERIC Educational Resources Information Center

    Denny, Mark

    2012-01-01

    Trees transport water from roots to crown--a height that can exceed 100 m. The physics of tree hydraulics can be conveyed with simple fluid dynamics based upon the Hagen-Poiseuille equation and Murray's law. Here the conduit structure is modelled as conical pipes and as branching pipes. The force required to lift sap is generated mostly by…

  16. A new hybrid Christmas tree

    Treesearch

    William B. Critchfield

    1965-01-01

    A hybrid pine developed in the course of forest-tree improvement research. by the U. S. Forest Service has caught the interest of Christmas tree growers. It is a hybrid between two races of lodgepole pine (Pinus contorta) produced at the Institute of Forest Genetics at Placerville, California, and has some desirable attributes for use as a Christmas...

  17. Temperature and tree growth [editorial

    Treesearch

    Michael G. Ryan

    2010-01-01

    Tree growth helps US forests take up 12% of the fossil fuels emitted in the USA (Woodbury et al. 2007), so predicting tree growth for future climates matters. Predicting future climates themselves is uncertain, but climate scientists probably have the most confidence in predictions for temperature. Temperatures are projected to rise by 0.2 °C in the next two decades,...

  18. Tree physiology and bark beetles

    Treesearch

    Michael G. Ryan; Gerard Sapes; Anna Sala; Sharon Hood

    2015-01-01

    Irruptive bark beetles usually co-occur with their co-evolved tree hosts at very low (endemic) population densities. However, recent droughts and higher temperatures have promoted widespread tree mortality with consequences for forest carbon, fire and ecosystem services (Kurz et al., 2008; Raffa et al., 2008; Jenkins et al., 2012). In this issue of New Phytologist,...

  19. The Group Tree of Experience.

    ERIC Educational Resources Information Center

    Ping, Ki

    1994-01-01

    Describes a group activity that uses a tree as a metaphor to reflect both group and personal growth during adventure activities. The tree's roots represent the group's formation, the branches and leaves represent the group's diversity and capabilities, and the seeds represent the personal learning and growth that took place within the group.…

  20. Mixtures of (Constrained) Ultrametric Trees.

    ERIC Educational Resources Information Center

    Wedel, Michel; DeSarbo, Wayne S.

    1998-01-01

    Presents a method for the estimation of ultrametric trees calibrated on subjects' pairwise proximity judgments of stimuli, capturing subject heterogeneity using a finite mixture formulation. An empirical example from published data shows the ability to deal with external constraints on the tree topology. (Author/SLD)

  1. Restoring the American chestnut tree

    Treesearch

    Bryan Burhans; Fredrick V. Hebard

    2012-01-01

    The American chestnut (Castanea dentata) was a dominate hardwood tree in the eastern United States. Its historic range extended from Maine south to the northern parts of Georgia, Alabama, Mississippi, and west to the Ohio River Valley. In 1904, an exotic Asian fungus responsible for the death of American chestnut trees was first identified at the Bronx Zoo (New York...

  2. Tree Hydraulics: How Sap Rises

    ERIC Educational Resources Information Center

    Denny, Mark

    2012-01-01

    Trees transport water from roots to crown--a height that can exceed 100 m. The physics of tree hydraulics can be conveyed with simple fluid dynamics based upon the Hagen-Poiseuille equation and Murray's law. Here the conduit structure is modelled as conical pipes and as branching pipes. The force required to lift sap is generated mostly by…

  3. The limits to tree height.

    PubMed

    Koch, George W; Sillett, Stephen C; Jennings, Gregory M; Davis, Stephen D

    2004-04-22

    Trees grow tall where resources are abundant, stresses are minor, and competition for light places a premium on height growth. The height to which trees can grow and the biophysical determinants of maximum height are poorly understood. Some models predict heights of up to 120 m in the absence of mechanical damage, but there are historical accounts of taller trees. Current hypotheses of height limitation focus on increasing water transport constraints in taller trees and the resulting reductions in leaf photosynthesis. We studied redwoods (Sequoia sempervirens), including the tallest known tree on Earth (112.7 m), in wet temperate forests of northern California. Our regression analyses of height gradients in leaf functional characteristics estimate a maximum tree height of 122-130 m barring mechanical damage, similar to the tallest recorded trees of the past. As trees grow taller, increasing leaf water stress due to gravity and path length resistance may ultimately limit leaf expansion and photosynthesis for further height growth, even with ample soil moisture.

  4. Studying Evergreen Trees in December.

    ERIC Educational Resources Information Center

    Platt, Dorothy K.

    1991-01-01

    This lesson plan uses evergreen trees on sale in cities and villages during the Christmas season to teach identification techniques. Background information, activities, and recommended references guides deal with historical, symbolic and current uses of evergreen trees, physical characteristics, selection, care, and suggestions for post-Christmas…

  5. Basswood, linden, lime-tree,

    Treesearch

    John Zasada

    2003-01-01

    Tilia americana - to foresters, botanists, and ecologists around the world this name conjures up the picture of a very specific tree (Tilia in latin means linden tree so literally translated the scientific name means American linden). But what about basswood, linden, lime, and pu tee shu (Chinese for linden)? Common names are often confusing and may be different from...

  6. The Minnesota Tree Improvement Cooperative

    Treesearch

    Andrew David

    2002-01-01

    As the director of the Minnesota Tree Improvement Cooperative (MTIC) based in Cloquet, Minnesota, I would like to tell you a little about our strategy for creating improved seed, and how individual nurseries or nursery associations can interact with tree improvement programs to the benefit of both parties. MTIC is approximately 15 miles west of Duluth, at the...

  7. Looking/Learning Drawing: Trees.

    ERIC Educational Resources Information Center

    Hurwitz, Al; Blume, Sharon

    1985-01-01

    Secondary students are asked to study and compare three reproductions--Van Gogh's "Grove of Cypresses," Da Vinci's "Study of a Tree," and Mondrian's "Tree II." The activity will help students develop their powers of observation and analysis, powers that can be applied to their own drawings. (RM)

  8. Tree Decay - An Expanded Concept

    Treesearch

    Alex L. Shigo

    1979-01-01

    The purpose of this publication is to clarify further the tree decay concept that expands the classical concept to include the orderly response of the tree to wounding and infection-compartmentalization-and the orderly infection of wounds by many microorganisms-successions. The heartrot concept must be abandoned because it deals only with decay-causing fungi and it...

  9. Fractions, trees and unfinished business

    NASA Astrophysics Data System (ADS)

    Shraiman, Boris

    In this talk, mourning the loss of a teacher and a dear friend, I would like to share some unfinished thoughts loosely connecting - via Farey fraction trees - Kadanoff's study of universality of quasi-periodic route to chaos with the effort to understand universal features of genealogical trees.

  10. The Group Tree of Experience.

    ERIC Educational Resources Information Center

    Ping, Ki

    1994-01-01

    Describes a group activity that uses a tree as a metaphor to reflect both group and personal growth during adventure activities. The tree's roots represent the group's formation, the branches and leaves represent the group's diversity and capabilities, and the seeds represent the personal learning and growth that took place within the group.…

  11. Who pays for tree improvement?

    Treesearch

    Tom D. Byram; E. M. Raley

    2011-01-01

    Tree improvement has been one of the most successful collaborative research efforts in history, eliciting participation from a wide variety of players. This effort has included state forestry agencies, research universities, integrated forest industries, and the USDA Forest Service. Tree improvement was organized through cooperatives whose objectives were to distribute...

  12. Rubbery Polya Tree

    PubMed Central

    NIETO-BARAJAS, LUIS E.; MÜLLER, PETER

    2013-01-01

    Polya trees (PT) are random probability measures which can assign probability 1 to the set of continuous distributions for certain specifications of the hyperparameters. This feature distinguishes the PT from the popular Dirichlet process (DP) model which assigns probability 1 to the set of discrete distributions. However, the PT is not nearly as widely used as the DP prior. Probably the main reason is an awkward dependence of posterior inference on the choice of the partitioning subsets in the definition of the PT. We propose a generalization of the PT prior that mitigates this undesirable dependence on the partition structure, by allowing the branching probabilities to be dependent within the same level. The proposed new process is not a PT anymore. However, it is still a tail-free process and many of the prior properties remain the same as those for the PT. PMID:24368872

  13. 36 CFR 223.4 - Exchange of trees or portions of trees.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 2 2013-07-01 2013-07-01 false Exchange of trees or portions of trees. 223.4 Section 223.4 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF... PRODUCTS General Provisions § 223.4 Exchange of trees or portions of trees. Trees or portions of trees...

  14. 36 CFR 223.4 - Exchange of trees or portions of trees.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 2 2011-07-01 2011-07-01 false Exchange of trees or portions of trees. 223.4 Section 223.4 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF... PRODUCTS General Provisions § 223.4 Exchange of trees or portions of trees. Trees or portions of trees...

  15. 36 CFR 223.4 - Exchange of trees or portions of trees.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 2 2014-07-01 2014-07-01 false Exchange of trees or portions of trees. 223.4 Section 223.4 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF... PRODUCTS General Provisions § 223.4 Exchange of trees or portions of trees. Trees or portions of trees...

  16. 36 CFR 223.4 - Exchange of trees or portions of trees.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 2 2012-07-01 2012-07-01 false Exchange of trees or portions of trees. 223.4 Section 223.4 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF... PRODUCTS General Provisions § 223.4 Exchange of trees or portions of trees. Trees or portions of trees...

  17. Tree reconstruction from partial orders

    SciTech Connect

    Kannan, S.K. ); Warnow, T.J. )

    1993-01-01

    The problem of constructing trees given a matrix of interleaf distances is motivated by applications in computational evolutionary biology and linguistics. The general problem is to find an edge-weighted tree which most closely approximates the distance matrix. Although the construction problem is easy when the tree exactly fits the distance matrix, optimization problems under all popular criteria are either known or conjectured to be NP-complete. In this paper we consider the related problem where we are given a partial order on the pairwise distances, and wish to construct (if possible) an edge-weighted tree realizing the partial order. In particular we are interested in partial orders which arise from experiments on triples of species, which determine either a linear ordering of the three pairwise distances (called Total Order Model or TOM experiments) or only the pair(s) of minimum distance apart (called Partial Order Model or POM experiments). The POM and TOM experimental model is inspired by the model proposed by Kannan, Lawler, and Warnow for constructing trees from experiments which determine the rooted topology for any triple of species. We examine issues of construction of trees and consistency of TOM and POM experiments, where the trees may either be weighted or unweighted. Using these experiments to construct unweighted trees without nodes of degree two is motivated by a similar problem studied by Winkler, called the Discrete Metric Realization problem, which he showed to be strongly NP-hard. We have the following results: Determining consistency of a set of TOM or POM experiments is NP-Complete whether the tree is weighted or constrained to be unweighted and without degree two nodes. We can construct unweighted trees without degree two nodes from TOM experiments in optimal O(n[sup 3]) time and from POM experiments in O(n[sup 4]) time.

  18. Tree reconstruction from partial orders

    SciTech Connect

    Kannan, S.K.; Warnow, T.J.

    1993-03-01

    The problem of constructing trees given a matrix of interleaf distances is motivated by applications in computational evolutionary biology and linguistics. The general problem is to find an edge-weighted tree which most closely approximates the distance matrix. Although the construction problem is easy when the tree exactly fits the distance matrix, optimization problems under all popular criteria are either known or conjectured to be NP-complete. In this paper we consider the related problem where we are given a partial order on the pairwise distances, and wish to construct (if possible) an edge-weighted tree realizing the partial order. In particular we are interested in partial orders which arise from experiments on triples of species, which determine either a linear ordering of the three pairwise distances (called Total Order Model or TOM experiments) or only the pair(s) of minimum distance apart (called Partial Order Model or POM experiments). The POM and TOM experimental model is inspired by the model proposed by Kannan, Lawler, and Warnow for constructing trees from experiments which determine the rooted topology for any triple of species. We examine issues of construction of trees and consistency of TOM and POM experiments, where the trees may either be weighted or unweighted. Using these experiments to construct unweighted trees without nodes of degree two is motivated by a similar problem studied by Winkler, called the Discrete Metric Realization problem, which he showed to be strongly NP-hard. We have the following results: Determining consistency of a set of TOM or POM experiments is NP-Complete whether the tree is weighted or constrained to be unweighted and without degree two nodes. We can construct unweighted trees without degree two nodes from TOM experiments in optimal O(n{sup 3}) time and from POM experiments in O(n{sup 4}) time.

  19. Part 3: Urban Tree Planting Guide

    Treesearch

    Karen Cappiella; Tom Schueler; Jennifer Tomlinson; Tiffany Wright

    2006-01-01

    This manual provides detailed guidance on urban tree planting that applies at both the development site and the watershed scale. Topics covered include: species selection, site preparation, tree planting and maintenance techniques, and special considerations for urban tree planting.

  20. A Cost Benefit Analysis of Urban Trees

    SciTech Connect

    Akbari, Hashem

    1997-09-01

    Urban shade trees offer significant benefits in reducing building air- conditioning and improving urban air quality by reducing smog. The savings associated with these benefits varies by climate regions and can be up to $200 per tree. The cost of planting trees and maintaining them can vary from $10 to $500 per tree. Tree planting programs can be designed offer savings to communities that plant trees.

  1. SOFT TREE: Fault Tree Technique as Applied to Software. Revision.

    DTIC Science & Technology

    1983-10-01

    I -A64 748 SOFT TREE: FAULT TREE TECHNIQUE AS APPLIED TO SOFTUdRE i/ iI REVISION(U) RMAMENT DIV (AFSC) EGLIN AFB FLI DIRECTORATE OF SYSTEMS SAFETY J N...BUREAU OF STANDARDS-1963-A IN .," !.. - .4 0 / 0 ir r * .. a ,. I. ~ a I *~~ II - VI ~. p (I * ’. I, 0 @1 0 0 0 07 0- 1. - -d -1 -~ SOFT TREE FAULT...Safety Program Manager Reviewed by: William B. Collins Director, Systems Safety ii -.. w -w %v -Lx r-wu-lw."w-w-11 W w-u- 7- -m W - UnclassifiedIL

  2. Through bore subsea christmas trees

    SciTech Connect

    Huber, D.S.; Simmers, G.F.C.; Johnson, C.S.

    1985-01-01

    The workovers of subsea completed wells are expensive and time consuming as even the most routine tasks must be carried out by a semi-submersible. This paper describes the economic, safety and operational advantages which led to the development and successful first installation of 'through bore' subsea production trees. The conventional wet subsea trees have proved to be very reliable over the past ten years of operation in the Argyll, Duncan and Innes fields, however the completion strings require pulling on the average about once every three to five years. The conventional subsea tree/tubing hanger set up design requires the tree to be tripped and a rig BOP stack run to pull the tubing. This operation is time consuming, very weather sensitive and leaves the well temporarily without a well control stack on the wellhead. The 7 1/16'' 'through bore' subsea tree was developed to minimize the tubing pulling workover time and several trees have been run successfully since the latter part of 1984. The time saving on a tubing pulling workover is three days. In addition, the design considerably reduces the hazards and equipment damage risk inherent in the conventional design. Hamilton Brothers and National Supply Company in Aberdeen designed the equipment which must be considered a new generation of subsea production trees.

  3. Terrestrial apes and phylogenetic trees

    PubMed Central

    Arsuaga, Juan Luis

    2010-01-01

    The image that best expresses Darwin’s thinking is the tree of life. However, Darwin’s human evolutionary tree lacked almost everything because only the Neanderthals were known at the time and they were considered one extreme expression of our own species. Darwin believed that the root of the human tree was very deep and in Africa. It was not until 1962 that the root was shown to be much more recent in time and definitively in Africa. On the other hand, some neo-Darwinians believed that our family tree was not a tree, because there were no branches, but, rather, a straight stem. The recent years have witnessed spectacular discoveries in Africa that take us close to the origin of the human tree and in Spain at Atapuerca that help us better understand the origin of the Neanderthals as well as our own species. The final form of the tree, and the number of branches, remains an object of passionate debate. PMID:20445090

  4. Fault trees and sequence dependencies

    NASA Technical Reports Server (NTRS)

    Dugan, Joanne Bechta; Boyd, Mark A.; Bavuso, Salvatore J.

    1990-01-01

    One of the frequently cited shortcomings of fault-tree models, their inability to model so-called sequence dependencies, is discussed. Several sources of such sequence dependencies are discussed, and new fault-tree gates to capture this behavior are defined. These complex behaviors can be included in present fault-tree models because they utilize a Markov solution. The utility of the new gates is demonstrated by presenting several models of the fault-tolerant parallel processor, which include both hot and cold spares.

  5. STRAW: Species TRee Analysis Web server

    PubMed Central

    Shaw, Timothy I.; Ruan, Zheng; Glenn, Travis C.; Liu, Liang

    2013-01-01

    The coalescent methods for species tree reconstruction are increasingly popular because they can accommodate coalescence and multilocus data sets. Herein, we present STRAW, a web server that offers workflows for reconstruction of phylogenies of species using three species tree methods—MP-EST, STAR and NJst. The input data are a collection of rooted gene trees (for STAR and MP-EST methods) or unrooted gene trees (for NJst). The output includes the estimated species tree, modified Robinson-Foulds distances between gene trees and the estimated species tree and visualization of trees to compare gene trees with the estimated species tree. The web sever is available at http://bioinformatics.publichealth.uga.edu/SpeciesTreeAnalysis/. PMID:23661681

  6. Falls from trees and tree associated injuries in rural Melanesians.

    PubMed Central

    Barss, P; Dakulala, P; Doolan, M

    1984-01-01

    Falls from trees and other tree related injuries are the most common cause of trauma in some parts of rural Melanesia. A four year review of all admissions for trauma to the Provincial Hospital at Alotau, Milne Bay Province, Papua New Guinea, showed that 27% were due to falls from trees, and a further 10% were due to related injuries, such as being struck by a falling branch or a coconut. A questionnaire distributed to rural health centres showed that during the study period at least 28 villagers died from falls from trees before reaching hospital. Head and chest trauma were common causes of death. Many injured patients were boys. Forearm fractures were the most common injuries, but more serious injuries were also frequently encountered. Trees responsible for most deaths and injuries included the coconut palm, betel palm, mango, and breadfruit. There are many strategies for preventing such injuries; perhaps the most important is to stop small boys climbing tall trees. Such falls are a serious occupational hazard for many subsistence farmers. Images FIG 1 FIG 2 FIG 3 FIG 4 PMID:6440619

  7. Falls from trees and tree associated injuries in rural Melanesians.

    PubMed

    Barss, P; Dakulala, P; Doolan, M

    Falls from trees and other tree related injuries are the most common cause of trauma in some parts of rural Melanesia. A four year review of all admissions for trauma to the Provincial Hospital at Alotau, Milne Bay Province, Papua New Guinea, showed that 27% were due to falls from trees, and a further 10% were due to related injuries, such as being struck by a falling branch or a coconut. A questionnaire distributed to rural health centres showed that during the study period at least 28 villagers died from falls from trees before reaching hospital. Head and chest trauma were common causes of death. Many injured patients were boys. Forearm fractures were the most common injuries, but more serious injuries were also frequently encountered. Trees responsible for most deaths and injuries included the coconut palm, betel palm, mango, and breadfruit. There are many strategies for preventing such injuries; perhaps the most important is to stop small boys climbing tall trees. Such falls are a serious occupational hazard for many subsistence farmers.

  8. Abstraction and analysis of clinical guidance trees.

    PubMed

    Turner, Kenneth J

    2009-04-01

    The aims of this work were: to define an abstract notation for interactive decision trees; to formally analyse exploration errors in such trees through automated translation to Lotos (language of temporal ordering specification); to generate tree implementations through automated translation for an existing tree viewer, and to demonstrate the approach on healthcare examples created by the CGT (clinical guidance tree) project. An abstract and machine-readable notation was developed for describing clinical guidance trees: Ad/it (abstract decision/interactive trees). A methodology has been designed for creating trees using Ad/it. In particular, tree structure is separated from tree content. Tree structure and flow are designed and evaluated before committing to detailed content of the tree. Software tools have been created to translate Ad/it tree descriptions into Lotos and into CGT Viewer format. These representations support formal analysis and interactive exploration of decision trees. Through automated conversion of existing CGT trees, realistic healthcare applications have been used to validate the approach. All key objectives of the work have been achieved. An abstract notation has been created for decision trees, and is supported by automated translation and analysis. Although healthcare applications have been the main focus to date, the approach is generic and of value in almost any domain where decision trees are useful.

  9. Fremont Tree-Well Filter

    EPA Pesticide Factsheets

    Information about the SFBWQP Fremont Tree-Well Filter Spine project, part of an EPA competitive grant program to improve SF Bay water quality focused on restoring impaired waters and enhancing aquatic resources.

  10. A valuable tree by gum!

    PubMed

    Forrest, M

    2000-06-01

    Which majestic ornamental tree, conspicuous in the Australian landscape, has ten million hectares in cultivation worldwide--yielding timber, fuel, essential oil and cut foliage? It could only be eucalyptus.

  11. Trees for Reclamation Symposium Proceedings

    Treesearch

    Northeastern Forest Experiment Station

    1980-01-01

    A collection of 30 papers presented at the symposium on trees for reclamation in the Eastern United States held October 27-29, 1980, Lexington, Kentucky, and sponsored by the USDA Forest Service and Interstate Mining Compact Commission.

  12. Fault Tree Analysis: A Bibliography

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Fault tree analysis is a top-down approach to the identification of process hazards. It is as one of the best methods for systematically identifying an graphically displaying the many ways some things can go wrong. This bibliography references 266 documents in the NASA STI Database that contain the major concepts. fault tree analysis, risk an probability theory, in the basic index or major subject terms. An abstract is included with most citations, followed by the applicable subject terms.

  13. Generic physical protection logic trees

    SciTech Connect

    Paulus, W.K.

    1981-10-01

    Generic physical protection logic trees, designed for application to nuclear facilities and materials, are presented together with a method of qualitative evaluation of the trees for design and analysis of physical protection systems. One or more defense zones are defined where adversaries interact with the physical protection system. Logic trees that are needed to describe the possible scenarios within a defense zone are selected. Elements of a postulated or existing physical protection system are tagged to the primary events of the logic tree. The likelihood of adversary success in overcoming these elements is evaluated on a binary, yes/no basis. The effect of these evaluations is propagated through the logic of each tree to determine whether the adversary is likely to accomplish the end event of the tree. The physical protection system must be highly likely to overcome the adversary before he accomplishes his objective. The evaluation must be conducted for all significant states of the site. Deficiencies uncovered become inputs to redesign and further analysis, closing the loop on the design/analysis cycle.

  14. Short Tree, Long Tree, Right Tree, Wrong Tree: New Acquisition Bias Corrections for Inferring SNP Phylogenies

    PubMed Central

    Leaché, Adam D.; Banbury, Barbara L.; Felsenstein, Joseph; de Oca, Adrián nieto-Montes; Stamatakis, Alexandros

    2015-01-01

    Single nucleotide polymorphisms (SNPs) are useful markers for phylogenetic studies owing in part to their ubiquity throughout the genome and ease of collection. Restriction site associated DNA sequencing (RADseq) methods are becoming increasingly popular for SNP data collection, but an assessment of the best practises for using these data in phylogenetics is lacking. We use computer simulations, and new double digest RADseq (ddRADseq) data for the lizard family Phrynosomatidae, to investigate the accuracy of RAD loci for phylogenetic inference. We compare the two primary ways RAD loci are used during phylogenetic analysis, including the analysis of full sequences (i.e., SNPs together with invariant sites), or the analysis of SNPs on their own after excluding invariant sites. We find that using full sequences rather than just SNPs is preferable from the perspectives of branch length and topological accuracy, but not of computational time. We introduce two new acquisition bias corrections for dealing with alignments composed exclusively of SNPs, a conditional likelihood method and a reconstituted DNA approach. The conditional likelihood method conditions on the presence of variable characters only (the number of invariant sites that are unsampled but known to exist is not considered), while the reconstituted DNA approach requires the user to specify the exact number of unsampled invariant sites prior to the analysis. Under simulation, branch length biases increase with the amount of missing data for both acquisition bias correction methods, but branch length accuracy is much improved in the reconstituted DNA approach compared to the conditional likelihood approach. Phylogenetic analyses of the empirical data using concatenation or a coalescent-based species tree approach provide strong support for many of the accepted relationships among phrynosomatid lizards, suggesting that RAD loci contain useful phylogenetic signal across a range of divergence times despite the

  15. Short Tree, Long Tree, Right Tree, Wrong Tree: New Acquisition Bias Corrections for Inferring SNP Phylogenies.

    PubMed

    Leaché, Adam D; Banbury, Barbara L; Felsenstein, Joseph; de Oca, Adrián Nieto-Montes; Stamatakis, Alexandros

    2015-11-01

    Single nucleotide polymorphisms (SNPs) are useful markers for phylogenetic studies owing in part to their ubiquity throughout the genome and ease of collection. Restriction site associated DNA sequencing (RADseq) methods are becoming increasingly popular for SNP data collection, but an assessment of the best practises for using these data in phylogenetics is lacking. We use computer simulations, and new double digest RADseq (ddRADseq) data for the lizard family Phrynosomatidae, to investigate the accuracy of RAD loci for phylogenetic inference. We compare the two primary ways RAD loci are used during phylogenetic analysis, including the analysis of full sequences (i.e., SNPs together with invariant sites), or the analysis of SNPs on their own after excluding invariant sites. We find that using full sequences rather than just SNPs is preferable from the perspectives of branch length and topological accuracy, but not of computational time. We introduce two new acquisition bias corrections for dealing with alignments composed exclusively of SNPs, a conditional likelihood method and a reconstituted DNA approach. The conditional likelihood method conditions on the presence of variable characters only (the number of invariant sites that are unsampled but known to exist is not considered), while the reconstituted DNA approach requires the user to specify the exact number of unsampled invariant sites prior to the analysis. Under simulation, branch length biases increase with the amount of missing data for both acquisition bias correction methods, but branch length accuracy is much improved in the reconstituted DNA approach compared to the conditional likelihood approach. Phylogenetic analyses of the empirical data using concatenation or a coalescent-based species tree approach provide strong support for many of the accepted relationships among phrynosomatid lizards, suggesting that RAD loci contain useful phylogenetic signal across a range of divergence times despite the

  16. 75 FR 25103 - Tree Assistance Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-07

    ... Parts 760 and 783 Commodity Credit Corporation 7 CFR Part 1416 RIN 0560-AH96 Tree Assistance Program... rule implements specific requirements for the Tree Assistance Program (TAP) authorized by the Food... orchardists and nursery tree growers to replant or rehabilitate trees, bushes, and vines that were lost due...

  17. Field guide to red tree vole nests

    Treesearch

    Damon B. Lesmeister; James K. Swingle

    2017-01-01

    Surveys for red tree vole (Arborimus longicaudus) nests require tree climbing because the species is a highly specialized arboreal rodent that live in the tree canopy of coniferous forests in western Oregon and northwestern California. Tree voles are associated with old coniferous forest (≥80 years old) that are structurally complex, but are often...

  18. How To Select and Plant a Tree.

    ERIC Educational Resources Information Center

    Fazio, James R., Ed.

    1991-01-01

    This bulletin furnishes information about selecting and planting trees. The tree selection process includes being aware of the physical characteristics of bare root seedlings, containerized seedlings, balled and burlapped, or potted trees and determining the proper size and root ball proportions. The section on tree planting discusses how to: (1)…

  19. Factors that influence Christmas tree sales

    Treesearch

    Thomas H. Pendleton; Lawrence D. Garrett

    1970-01-01

    An analysis of the metropolitan Christmas tree market in Winston-Salem, N. C., shows that to sell more trees, Christmas tree retailers should locate their lots on heavily traveled streets in business areas, have adequate parking facilities, advertise, and have attractive displays of trees. Retailers who follow these practices can expect to receive higher prices for...

  20. Pocket guide to Christmas tree diseases

    Treesearch

    Thomas H. Nicholls; Robert D. Wray

    1989-01-01

    Each year more than 30 million American families bring a live Christmas tree into their homes to become the warm and glowing center of their Christmas celebration. Years ago, most Christmas trees were cut wild. But, as demand increased and the supply of suitable wild trees decreased, growing Christmas trees in plantations became more and more common.

  1. Christmas Tree Pest Manual, Third Edition

    Treesearch

    Steven Katovich; Deborah McCullough; Michael Ostry; Jill O’Donnell; Isabel Munck; Cliff Sadof

    2014-01-01

    Continuing mortality of red pine from an unknown cause has been observed in 30 to 40 year old plantations in southern and west central Wisconsin. A single tree or small group of trees die, followed by mortality of adjacent trees. These circular pockets of dead trees expand up to 0.3 acre per year.

  2. Hardwood Regeneration After Seed Tree Cutting

    Treesearch

    Robert L. Johnson; R. M. Krinard

    1976-01-01

    Seed trees left at two sites did not appear to influence the establishment or development of reproduction . Seed trees were mainly sweetgum and red oaks. Most reproduction was from sprouting of the stumps and roots of cut trees or from advanced seedlings present in the understory at the time of cutting. Eighteen years after cutting, dominant trees of the reproduction...

  3. Tree Defects: A Photo Guide Part C

    Treesearch

    Alex L. Shigo

    1983-01-01

    This guide shows, in 110 photos, how discoloration and decay form in trees. An expanded concept of tree decay is given. After wounding, trees form boundaries to resist the spread of pathogens. The boundary-setting defense process is called compartmentalization, and model of the process is CODIT. The expanded concept and the model are used to reexamine many other tree...

  4. Tree Defects: A Photo Guide Part B

    Treesearch

    Alex L. Shigo

    1983-01-01

    This guide shows, in 110 photos, how discoloration and decay form in trees. An expanded concept of tree decay is given. After wounding, trees form boundaries to resist the spread of pathogens. The boundary-setting defense process is called compartmentalization, and model of the process is CODIT. The expanded concept and the model are used to reexamine many other tree...

  5. Imaging tree roots with borehole radar

    Treesearch

    John R. Butnor; Kurt H. Johnsen; Per Wikstrom; Tomas Lundmark; Sune Linder

    2006-01-01

    Ground-penetrating radar has been used to de-tect and map tree roots using surface-based antennas in reflection mode. On amenable soils these methods can accurately detect lateral tree roots. In some tree species (e.g. Pinus taeda, Pinus palustris), vertically orientated tap roots directly beneath the tree, comprise most of the root mass. It is...

  6. A Tool for Displaying Syntactic Trees.

    ERIC Educational Resources Information Center

    Morgan, Jerry L.

    A computer program for drawing syntactic phrase markers as trees is described. The program was developed for use on Texas Instruments Explorer Lisp machines. The tree is drawn by recursive descent, left to right. The tree-drawing function takes two arguments: (1) an atom constituting the tree, and (2) a font specification to be used in drawing the…

  7. Atmospheric carbon reduction by urban trees

    Treesearch

    David J. Nowak

    1993-01-01

    Trees, because they sequester atmospheric carbon through their growth process and conserve energy in urban areas, have been suggested as one means to combat increasing levels of atmospheric carbon. Analysis of the urban forest in Oakland, California (21% tree cover), reveals a tree carbon storage level of 11.0 metric tons/hectare. Trees in the area of the 1991 fire in...

  8. A Tool for Displaying Syntactic Trees.

    ERIC Educational Resources Information Center

    Morgan, Jerry L.

    A computer program for drawing syntactic phrase markers as trees is described. The program was developed for use on Texas Instruments Explorer Lisp machines. The tree is drawn by recursive descent, left to right. The tree-drawing function takes two arguments: (1) an atom constituting the tree, and (2) a font specification to be used in drawing the…

  9. Growing a Forest for the Trees.

    ERIC Educational Resources Information Center

    Growing Ideas, 2001

    2001-01-01

    Describes a tree studies program in a fourth-grade classroom. Students collected local tree seeds and seeds from supermarket fruits, researched growing conditions, and grew seeds under various conditions. Students kept journals on local trees, observing seed dispersal mechanisms and examining rings on trunk slices. Inquiry-based tree studies…

  10. Tree Defects: A Photo Guide Part A

    Treesearch

    Alex L Shigo

    1983-01-01

    This guide shows, in 110 photos, how discoloration and decay form in trees. An expanded concept of tree decay is given. After wounding, trees form boundaries to resist the spread of pathogens. The boundary-setting defense process is called compartmentalization, and model of the process is CODIT. The expanded concept and the model are used to reexamine many other tree...

  11. Growing a Forest for the Trees.

    ERIC Educational Resources Information Center

    Growing Ideas, 2001

    2001-01-01

    Describes a tree studies program in a fourth-grade classroom. Students collected local tree seeds and seeds from supermarket fruits, researched growing conditions, and grew seeds under various conditions. Students kept journals on local trees, observing seed dispersal mechanisms and examining rings on trunk slices. Inquiry-based tree studies…

  12. Critical wind speed at which trees break.

    PubMed

    Virot, E; Ponomarenko, A; Dehandschoewercker, É; Quéré, D; Clanet, C

    2016-02-01

    Data from storms suggest that the critical wind speed at which trees break is constant (≃42m/s), regardless of tree characteristics. We question the physical origin of this observation both experimentally and theoretically. By combining Hooke's law, Griffith's criterion, and tree allometry, we show that the critical wind speed indeed hardly depends on the height, diameter, and elastic properties of trees.

  13. Critical wind speed at which trees break

    NASA Astrophysics Data System (ADS)

    Virot, E.; Ponomarenko, A.; Dehandschoewercker, É.; Quéré, D.; Clanet, C.

    2016-02-01

    Data from storms suggest that the critical wind speed at which trees break is constant (≃42 m /s ), regardless of tree characteristics. We question the physical origin of this observation both experimentally and theoretically. By combining Hooke's law, Griffith's criterion, and tree allometry, we show that the critical wind speed indeed hardly depends on the height, diameter, and elastic properties of trees.

  14. Microwave sensing of tree trunks

    NASA Astrophysics Data System (ADS)

    Jezova, Jana; Mertens, Laurence; Lambot, Sebastien

    2015-04-01

    The main subject of this research is the observation of the inner part of living tree trunks using ground-penetrating radar (GPR). Trees are everyday part of human life and therefore it is important to pay attention to the tree conditions. The most obvious consequence of the poor tree condition is dead or injury caused by falling tree. The trunk internal structure is divided into three main parts: heartwood, sapwood and bark, which make this medium highly anisotropic and heterogeneous. Furthermore, the properties of the wood are not only specie-dependent but also depend on genetic and on environmental conditions. In urban areas the main problem for the stability of the trees relies in the apparition of decays provoked by fungi, insect or birds. This results in cavities or decreasing of the support capacity of the tree. GPR has proved itself to be a very powerful electromagnetic tool for non-destructive detection of buried objects. Since the beginning of the 20th century it has been used in several different areas (archaeology, landmine detection, civil engineering, ...). GPR uses the principle of the scattering of the electromagnetic waves that are radiated from a transmitting antenna. Then the waves propagate through the medium and are reflected from the object and then they are received by a receiving antenna. The velocity of the scattered signal is determined primarily by the permittivity of the material. The optimal functionality of the GPR was investigated using the numerical simulation tool gprMax2D. This tool is based on a Finite-Difference Time-Domain (FDTD) numerical model. Subsequently, the GPR functionality was tested using the laboratory model of a decayed tree trunk. Afterwards, the results and lessons learnt in the simplified tests will be used in the processing of the real data and will help to achieve deeper understanding of them. The laboratory model of the tree trunk was made by plastic or carton pipes and filled by sand. Space inside the model

  15. Hi-trees and their layout.

    PubMed

    Marriott, Kim; Sbarski, Peter; van Gelder, Tim; Prager, Daniel; Bulka, Andy

    2011-03-01

    We introduce hi-trees, a new visual representation for hierarchical data in which, depending on the kind of parent node, the child relationship is represented using either containment or links. We give a drawing convention for hi-trees based on the standard layered drawing convention for rooted trees, then show how to extend standard bottom-up tree layout algorithms to draw hi-trees in this convention. We also explore a number of other more compact layout styles for layout of larger hi-trees and give algorithms for computing these. Finally, we describe two applications of hi-trees: argument mapping and business decision support.

  16. Cavity tree selection by red-cockaded woodpeckers in relation to tree age

    Treesearch

    D. Craig Rudolph; Richard N. Conner

    1991-01-01

    We aged over 1350 Red-cockaded Woodpecker (Picoides borealis) cavity trees and a comparable number of randomly selected trees. Resulting data strongly support the hypothesis that Red-cockaded Woodpeckers preferentially select older trees. Ages of recently initiated cavity trees in the Texas study areas generally were similar to those of cavity trees...

  17. Methane Emissions from Upland Trees

    NASA Astrophysics Data System (ADS)

    Pitz, S.; Megonigal, P.; Schile, L. M.; Szlavecz, K. A.; King, K.

    2013-12-01

    Most work on methane (CH4) emissions from natural ecosystems has focused on wetlands and wetland soils because they are predictable emitters and relatively simple to quantify. Less attention has been directed toward upland ecosystems that cover far larger areas, but are assumed to be too dry to emit CH4. There is abundant evidence that upland ecosystems emit small amounts of CH4 during hot moments that collectively constitute a significant source in the global budget of this potent greenhouse gas. We have established two transects across natural moisture gradients in two forests near Annapolis, Maryland. Both tree and soil methane fluxes were measured using chamber methods. Each tree chamber was custom fit to the stem near the base. In addition, porewater methane concentrations were collected at multiple depths near trees. Abiotic parameters such as soil temperature, soil moisture, water potential, and depth to groundwater were monitored using a wireless sensor network. Upland emissions from tree stems were as high as 14.6 umoles CH4 m-2 hr-1 while the soil uptake was -1.5 umoles CH4 m-2 hr-1. These results demonstrate that tree methane emissions and soil methane uptake can occur simultaneously in a mesic forest. Factors controlling methane emissions were soil temperature, soil moisture, and depth to groundwater. Based on our preliminary data, tree mediated methane emissions may be offsetting the soil methane sink of upland forests by 20 to 30%. Future methane budgets and climate models will need to include tree fluxes and the parameters that control methane emissions for accurate accounting and predictions.

  18. Genealogical trees from genetic distances

    NASA Astrophysics Data System (ADS)

    Prignano, L.; Serva, M.

    2009-06-01

    In a population with haploid reproduction any individual has a single parent in the previous generation. If all genealogical distances among pairs of individuals (generations from the closest common ancestor) are known it is possible to exactly reconstruct their genealogical tree. Unfortunately, in most cases, genealogical distances are unknown and only genetic distances are available. The genetic distance between two individuals is measurable from differences in mtDNA (mitochondrial DNA) since in the case of humans or other complex organisms mtDNA is transmitted in a haploid manner. An analogous distance can be also computed for languages where it may be measured from lexical differences, in this case, nevertheless, haploid reproduction is only a raw approximation. Assuming a constant rate of mutation, these genetic distances are random and proportional only on average to genealogical ones. The reconstruction of the genealogical tree from the available genetic distances is forceful imprecise. In this paper we try to quantify the error one may commit in the reconstruction of the tree for different degrees of randomness. The errors may concern both topology of the tree (the branching hierarchy) and, in case of correct topology, the proportions of the tree (length of various branches).

  19. Tree Growth Stage and Environment after Pathogen Inoculation Alters Susceptibility of Pear Trees to Phytophthora Canker

    USDA-ARS?s Scientific Manuscript database

    We investigated whether growth stage of pear (Pyrus communis) tree rootstock and environment after inoculation with Phytophthora syringae influences tree susceptibility to infection. Trees at different stages of dormancy development were inoculated with the pathogen and maintained in different condi...

  20. Guide to the measurement of tree characteristics important to the quality classification for young hardwood trees

    Treesearch

    David L. Sonderman

    1979-01-01

    A procedure is shown for measuring external tree characteristics that are important in determining the current and future quality of young hardwood trees. This guide supplements a precious study which describes the quality classification system for young hardwood trees

  1. Mapping tree density at a global scale.

    PubMed

    Crowther, T W; Glick, H B; Covey, K R; Bettigole, C; Maynard, D S; Thomas, S M; Smith, J R; Hintler, G; Duguid, M C; Amatulli, G; Tuanmu, M-N; Jetz, W; Salas, C; Stam, C; Piotto, D; Tavani, R; Green, S; Bruce, G; Williams, S J; Wiser, S K; Huber, M O; Hengeveld, G M; Nabuurs, G-J; Tikhonova, E; Borchardt, P; Li, C-F; Powrie, L W; Fischer, M; Hemp, A; Homeier, J; Cho, P; Vibrans, A C; Umunay, P M; Piao, S L; Rowe, C W; Ashton, M S; Crane, P R; Bradford, M A

    2015-09-10

    The global extent and distribution of forest trees is central to our understanding of the terrestrial biosphere. We provide the first spatially continuous map of forest tree density at a global scale. This map reveals that the global number of trees is approximately 3.04 trillion, an order of magnitude higher than the previous estimate. Of these trees, approximately 1.39 trillion exist in tropical and subtropical forests, with 0.74 trillion in boreal regions and 0.61 trillion in temperate regions. Biome-level trends in tree density demonstrate the importance of climate and topography in controlling local tree densities at finer scales, as well as the overwhelming effect of humans across most of the world. Based on our projected tree densities, we estimate that over 15 billion trees are cut down each year, and the global number of trees has fallen by approximately 46% since the start of human civilization.

  2. Coalescent Histories for Lodgepole Species Trees.

    PubMed

    Disanto, Filippo; Rosenberg, Noah A

    2015-10-01

    Coalescent histories are combinatorial structures that describe for a given gene tree and species tree the possible lists of branches of the species tree on which the gene tree coalescences take place. Properties of the number of coalescent histories for gene trees and species trees affect a variety of probabilistic calculations in mathematical phylogenetics. Exact and asymptotic evaluations of the number of coalescent histories, however, are known only in a limited number of cases. Here we introduce a particular family of species trees, the lodgepole species trees (λn)n ≥ 0, in which tree λn has m = 2n+1 taxa. We determine the number of coalescent histories for the lodgepole species trees, in the case that the gene tree matches the species tree, showing that this number grows with m!! in the number of taxa m. This computation demonstrates the existence of tree families in which the growth in the number of coalescent histories is faster than exponential. Further, it provides a substantial improvement on the lower bound for the ratio of the largest number of matching coalescent histories to the smallest number of matching coalescent histories for trees with m taxa, increasing a previous bound of [Formula: see text] to [Formula: see text]. We discuss the implications of our enumerative results for phylogenetic computations.

  3. Advanced tree-trimming equipment

    SciTech Connect

    Johnston, P.A.; Gillon, J.P. )

    1990-07-01

    A project funded by the Electric Power research Institute has produced a working prototype of a pantograph linkage supported, telescopic pole type tool with interchangeable cutting heads for trimming trees around electrical conductors. The tool is designed for mounting on the bucket of an aerial lift of the type commonly used for tree trimming. The three-section telescopic pole is constructed of non-conductive, filament wound, fiber-glass reinforced epoxy and is adjustable from an overall length of 7 feet to a fully extended length of 17 feet. The project goal was to obtain a 20% improvement in productivity of tree crews. Productivity gains are expected to result from fewer truck set-ups, faster tool positioning, and reduced user fatigue. The next phase of the project will involve test and evaluation of the prototype and will quantify actual productivity gains.

  4. Measurement of tree canopy architecture

    NASA Technical Reports Server (NTRS)

    Martens, S. N.; Ustin, S. L.; Norman, J. M.

    1991-01-01

    The lack of accurate extensive geometric data on tree canopies has retarded development and validation of radiative transfer models. A stratified sampling method was devised to measure the three-dimensional geometry of 16 walnut trees which had received irrigation treatments of either 100 or 33 per cent of evapotranspirational (ET) demand for the previous two years. Graphic reconstructions of the three-dimensional geometry were verified by 58 independent measurements. The distributions of stem- and leaf-size classes, lengths, and angle classes were determined and used to calculate leaf area index (LAI), stem area, and biomass. Reduced irrigation trees have lower biomass of stems, leaves and fruit, lower LAI, steeper leaf angles and altered biomass allocation to large stems. These data can be used in ecological models that link canopy processes with remotely sensed measurements.

  5. Measurement of tree canopy architecture

    NASA Technical Reports Server (NTRS)

    Martens, S. N.; Ustin, S. L.; Norman, J. M.

    1991-01-01

    The lack of accurate extensive geometric data on tree canopies has retarded development and validation of radiative transfer models. A stratified sampling method was devised to measure the three-dimensional geometry of 16 walnut trees which had received irrigation treatments of either 100 or 33 per cent of evapotranspirational (ET) demand for the previous two years. Graphic reconstructions of the three-dimensional geometry were verified by 58 independent measurements. The distributions of stem- and leaf-size classes, lengths, and angle classes were determined and used to calculate leaf area index (LAI), stem area, and biomass. Reduced irrigation trees have lower biomass of stems, leaves and fruit, lower LAI, steeper leaf angles and altered biomass allocation to large stems. These data can be used in ecological models that link canopy processes with remotely sensed measurements.

  6. 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.

  7. Trees, soils, and food security

    PubMed Central

    Sanchez, P. A.; Buresh, R. J.; Leakey, R. R. B.

    1997-01-01

    Trees have a different impact on soil properties than annual crops, because of their longer residence time, larger biomass accumulation, and longer-lasting, more extensive root systems. In natural forests nutrients are efficiently cycled with very small inputs and outputs from the system. In most agricultural systems the opposite happens. Agroforestry encompasses the continuum between these extremes, and emerging hard data is showing that successful agroforestry systems increase nutrient inputs, enhance internal flows, decrease nutrient losses and provide environmental benefits: when the competition for growth resources between the tree and the crop component is well managed. The three main determinants for overcoming rural poverty in Africa are (i) reversing soil fertility depletion, (ii) intensifying and diversifying land use with high-value products, and (iii) providing an enabling policy environment for the smallholder farming sector. Agroforestry practices can improve food production in a sustainable way through their contribution to soil fertility replenishment. The use of organic inputs as a source of biologically-fixed nitrogen, together with deep nitrate that is captured by trees, plays a major role in nitrogen replenishment. The combination of commercial phosphorus fertilizers with available organic resources may be the key to increasing and sustaining phosphorus capital. High-value trees, 'Cinderella' species, can fit in specific niches on farms, thereby making the system ecologically stable and more rewarding economically, in addition to diversifying and increasing rural incomes and improving food security. In the most heavily populated areas of East Africa, where farm size is extremely small, the number of trees on farms is increasing as farmers seek to reduce labour demands, compatible with the drift of some members of the family into the towns to earn off-farm income. Contrary to the concept that population pressure promotes deforestation, there is

  8. Transport of Methane in Trees

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

    Although overall methane (CH4) emissions for croplands, wetlands, and forests have been measured, the exact dynamics of CH4 transport through trees is not well understood. What roles transport mechanisms play in emission rates has been thoroughly investigated for rice, but is fairly unknown for trees. Better defined plant transport mechanisms yield more accurate determination of greenhouse gas flux and its variations, contributing to a comprehensive theory quantifying greenhouse gas emissions globally. CH4 emissions from the common wetland tree species black cottonwood (Populus trichocarpa) native to the Pacific Northwest have been measured under hydroponic conditions in order to separate plant transport processes from the influence of soil processes. Canopy emissions of CH4 have been measured via canopy enclosure. Measurements of CH4 flux from each of 16 trees have indicated that emissions are normally constant over the half-hour sampling period. Samples for stable carbon isotope composition have been taken during these experiments and measured on a mass spectrometer. Compared to the isotopic composition of root water CH4, canopy CH4 is depleted in 13C; this indicates that CH4 moving through the tree is not following a bulk flow pathway (where no depletion would occur), but instead moves either diffusively or through other cell or tissue barriers. No correlation was found to exist between leaf area and CH4 emission; this is vital to upscaling tree-level emissions to the global scale since leaf area index (LAI) cannot be treated as an appropriate parameter to upscale flux. Correctly informing global-scale CH4 fluxes from plants requires an association between the role plant physiology plays in the production and transport of CH4 and magnitudes of flux. This research was supported by the Office of Science (BER), U. S. Department of Energy, Grant No. DE-FG02-08ER64515. Supported in part through NASA / Oregon Space Grant Consortium, grant NNG05GJ85H.

  9. Attention trees and semantic paths

    NASA Astrophysics Data System (ADS)

    Giusti, Christian; Pieroni, Goffredo G.; Pieroni, Laura

    2007-02-01

    In the last few decades several techniques for image content extraction, often based on segmentation, have been proposed. It has been suggested that under the assumption of very general image content, segmentation becomes unstable and classification becomes unreliable. According to recent psychological theories, certain image regions attract the attention of human observers more than others and, generally, the image main meaning appears concentrated in those regions. Initially, regions attracting our attention are perceived as a whole and hypotheses on their content are formulated; successively the components of those regions are carefully analyzed and a more precise interpretation is reached. It is interesting to observe that an image decomposition process performed according to these psychological visual attention theories might present advantages with respect to a traditional segmentation approach. In this paper we propose an automatic procedure generating image decomposition based on the detection of visual attention regions. A new clustering algorithm taking advantage of the Delaunay- Voronoi diagrams for achieving the decomposition target is proposed. By applying that algorithm recursively, starting from the whole image, a transformation of the image into a tree of related meaningful regions is obtained (Attention Tree). Successively, a semantic interpretation of the leaf nodes is carried out by using a structure of Neural Networks (Neural Tree) assisted by a knowledge base (Ontology Net). Starting from leaf nodes, paths toward the root node across the Attention Tree are attempted. The task of the path consists in relating the semantics of each child-parent node pair and, consequently, in merging the corresponding image regions. The relationship detected in this way between two tree nodes generates, as a result, the extension of the interpreted image area through each step of the path. The construction of several Attention Trees has been performed and partial

  10. Interpreting the universal phylogenetic tree

    NASA Technical Reports Server (NTRS)

    Woese, C. R.

    2000-01-01

    The universal phylogenetic tree not only spans all extant life, but its root and earliest branchings represent stages in the evolutionary process before modern cell types had come into being. The evolution of the cell is an interplay between vertically derived and horizontally acquired variation. Primitive cellular entities were necessarily simpler and more modular in design than are modern cells. Consequently, horizontal gene transfer early on was pervasive, dominating the evolutionary dynamic. The root of the universal phylogenetic tree represents the first stage in cellular evolution when the evolving cell became sufficiently integrated and stable to the erosive effects of horizontal gene transfer that true organismal lineages could exist.

  11. Tree hydraulics: how sap rises

    NASA Astrophysics Data System (ADS)

    Denny, Mark

    2012-01-01

    Trees transport water from roots to crown—a height that can exceed 100 m. The physics of tree hydraulics can be conveyed with simple fluid dynamics based upon the Hagen-Poiseuille equation and Murray's law. Here the conduit structure is modelled as conical pipes and as branching pipes. The force required to lift sap is generated mostly by transpiration or capillary action; we investigate the effectiveness of both these forces for the two conduit architectures considered. The level of analysis is appropriate for undergraduates. The subject is of broad interest because it provides a naturally-occurring example of an unusual metastable state of matter: liquid under tension.

  12. Interpreting the universal phylogenetic tree

    PubMed Central

    Woese, Carl R.

    2000-01-01

    The universal phylogenetic tree not only spans all extant life, but its root and earliest branchings represent stages in the evolutionary process before modern cell types had come into being. The evolution of the cell is an interplay between vertically derived and horizontally acquired variation. Primitive cellular entities were necessarily simpler and more modular in design than are modern cells. Consequently, horizontal gene transfer early on was pervasive, dominating the evolutionary dynamic. The root of the universal phylogenetic tree represents the first stage in cellular evolution when the evolving cell became sufficiently integrated and stable to the erosive effects of horizontal gene transfer that true organismal lineages could exist. PMID:10900003

  13. Interpreting the universal phylogenetic tree.

    PubMed

    Woese, C R

    2000-07-18

    The universal phylogenetic tree not only spans all extant life, but its root and earliest branchings represent stages in the evolutionary process before modern cell types had come into being. The evolution of the cell is an interplay between vertically derived and horizontally acquired variation. Primitive cellular entities were necessarily simpler and more modular in design than are modern cells. Consequently, horizontal gene transfer early on was pervasive, dominating the evolutionary dynamic. The root of the universal phylogenetic tree represents the first stage in cellular evolution when the evolving cell became sufficiently integrated and stable to the erosive effects of horizontal gene transfer that true organismal lineages could exist.

  14. Water Transport in Trees--An Artificial Laboratory Tree

    ERIC Educational Resources Information Center

    Susman, K.; Razpet, N.; Cepic, M.

    2011-01-01

    Water transport in tall trees is an everyday phenomenon, seldom noticed and not completely understood even by scientists. As a topic of current research in plant physiology it has several advantages for presentation within school physics lectures: it is interdisciplinary and clearly shows the connection between physics and biology; the…

  15. The status of tree improvement programs for northern tree species

    Treesearch

    David S. Canavera

    1977-01-01

    Forest tree improvement research and application in the Northeast is reviewed in the perspective of past development and future needs. Control over provenance selection can provide the best quality seed for today's reforestation programs. Future supplies of seed must come from seed orchards if forest land owners are to attain the maximum production per unit area...

  16. Water Transport in Trees--An Artificial Laboratory Tree

    ERIC Educational Resources Information Center

    Susman, K.; Razpet, N.; Cepic, M.

    2011-01-01

    Water transport in tall trees is an everyday phenomenon, seldom noticed and not completely understood even by scientists. As a topic of current research in plant physiology it has several advantages for presentation within school physics lectures: it is interdisciplinary and clearly shows the connection between physics and biology; the…

  17. Tree Height Calculator: An Android App for Estimating Tree Height

    NASA Astrophysics Data System (ADS)

    Burca, V. S.; Htet, N. M.; Huang, X.; de Lanerolle, T. R.; Morelli, R.; Gourley, J. R.

    2011-12-01

    Conventionally, measuring tree height requires a collection of different tools - clinometer, transit, pencil, paper, laptop computer. Results are recorded manually and entered into a spreadsheet or database for future calculation and analysis. Tree Height Calculator is a mobile Android app the integrates the various steps in this process thereby improving the accuracy and dramatically reducing the time required to go from taking measurements to analyzing data. Given the user's height and the distance from the base of the tree (which can be downloaded into the app from a server), the app uses the phone's orientation sensor to calculate the angle of elevation. A simple trigonometric formula is then used to calculate and record the tree's height in the phone's database. When the phone has a WiFi connection, the data are transmitted to a server, from where they can be downloaded directly into a spreadsheet. The application was first tested in an Environmental Science laboratory at Trinity College. On the first trial, 103 data samples were collected, stored, and uploaded to the online database with only couple of dropped data points. On the second trial, 98 data samples were gathered with no loss of data. The app combined the individual measurements taken by the students in the lab, reducing the time required to produce a graph of the class's results from days to hours.

  18. Properties of Consensus Methods for Inferring Species Trees from Gene Trees

    PubMed Central

    Degnan, James H.; DeGiorgio, Michael; Bryant, David; Rosenberg, Noah A.

    2009-01-01

    Consensus methods provide a useful strategy for summarizing information from a collection of gene trees. An important application of consensus methods is to combine gene trees to estimate a species tree. To investigate the theoretical properties of consensus trees that would be obtained from large numbers of loci evolving according to a basic evolutionary model, we construct consensus trees from rooted gene trees that occur in proportion to gene-tree probabilities derived from coalescent theory. We consider majority-rule, rooted triple (R*), and greedy consensus trees obtained from known, rooted gene trees, both in the asymptotic case as numbers of gene trees approach infinity and for finite numbers of genes. Our results show that for some combinations of species-tree branch lengths, increasing the number of independent loci can make the rooted majority-rule consensus tree more likely to be at least partially unresolved. However, the probability that the R* consensus tree has the species-tree topology approaches 1 as the number of gene trees approaches ∞. Although the greedy consensus algorithm can be the quickest to converge on the correct species-tree topology when increasing the number of gene trees, it can also be positively misleading. The majority-rule consensus tree is not a misleading estimator of the species-tree topology, and the R* consensus tree is a statistically consistent estimator of the species-tree topology. Our results therefore suggest a method for using multiple loci to infer the species-tree topology, even when it is discordant with the most likely gene tree. PMID:20525567

  19. Axiomatic opportunities and obstacles for inferring a species tree from gene trees.

    PubMed

    Steel, Mike; Velasco, Joel D

    2014-09-01

    The reconstruction of a central tendency "species tree" from a large number of conflicting gene trees is a central problem in systematic biology. Moreover, it becomes particularly problematic when taxon coverage is patchy, so that not all taxa are present in every gene tree. Here, we list four apparently desirable properties that a method for estimating a species tree from gene trees could have (the strongest property states that building a species tree from input gene trees and then pruning leaves gives a tree that is the same as, or more resolved than, the tree obtained by first removing the taxa from the input trees and then building the species tree). We show that although it is technically possible to simultaneously satisfy these properties when taxon coverage is complete, they cannot all be satisfied in the more general supertree setting. In part two, we discuss a concordance-based consensus method based on Baum's "plurality clusters", and an extension to concordance supertrees.

  20. Identifying the rooted species tree from the distribution of unrooted gene trees under the coalescent.

    PubMed

    Allman, Elizabeth S; Degnan, James H; Rhodes, John A

    2011-06-01

    Gene trees are evolutionary trees representing the ancestry of genes sampled from multiple populations. Species trees represent populations of individuals-each with many genes-splitting into new populations or species. The coalescent process, which models ancestry of gene copies within populations, is often used to model the probability distribution of gene trees given a fixed species tree. This multispecies coalescent model provides a framework for phylogeneticists to infer species trees from gene trees using maximum likelihood or Bayesian approaches. Because the coalescent models a branching process over time, all trees are typically assumed to be rooted in this setting. Often, however, gene trees inferred by traditional phylogenetic methods are unrooted. We investigate probabilities of unrooted gene trees under the multispecies coalescent model. We show that when there are four species with one gene sampled per species, the distribution of unrooted gene tree topologies identifies the unrooted species tree topology and some, but not all, information in the species tree edges (branch lengths). The location of the root on the species tree is not identifiable in this situation. However, for 5 or more species with one gene sampled per species, we show that the distribution of unrooted gene tree topologies identifies the rooted species tree topology and all its internal branch lengths. The length of any pendant branch leading to a leaf of the species tree is also identifiable for any species from which more than one gene is sampled.

  1. Enumeration of Ancestral Configurations for Matching Gene Trees and Species Trees.

    PubMed

    Disanto, Filippo; Rosenberg, Noah A

    2017-09-01

    Given a gene tree and a species tree, ancestral configurations represent the combinatorially distinct sets of gene lineages that can reach a given node of the species tree. They have been introduced as a data structure for use in the recursive computation of the conditional probability under the multispecies coalescent model of a gene tree topology given a species tree, the cost of this computation being affected by the number of ancestral configurations of the gene tree in the species tree. For matching gene trees and species trees, we obtain enumerative results on ancestral configurations. We study ancestral configurations in balanced and unbalanced families of trees determined by a given seed tree, showing that for seed trees with more than one taxon, the number of ancestral configurations increases for both families exponentially in the number of taxa n. For fixed n, the maximal number of ancestral configurations tabulated at the species tree root node and the largest number of labeled histories possible for a labeled topology occur for trees with precisely the same unlabeled shape. For ancestral configurations at the root, the maximum increases with [Formula: see text], where [Formula: see text] is a quadratic recurrence constant. Under a uniform distribution over the set of labeled trees of given size, the mean number of root ancestral configurations grows with [Formula: see text] and the variance with ∼[Formula: see text]. The results provide a contribution to the combinatorial study of gene trees and species trees.

  2. Red tree vole / Arborimus longicaudus.

    Treesearch

    A.B. Carey

    1999-01-01

    The secretive nocturnal red tree vole is one of least studied and most specialized voles in North America. It is found only along the coast and in the Western Cascades of Oregon where it spends most of its life in the tops of tall conifers. eating needles of Douglas-fir (Pseudotsuga menziesii) and. Occasionally, other conifers. The voles clip small...

  3. Chopping Down the Cherry Tree.

    ERIC Educational Resources Information Center

    Griswold, Jerry

    1995-01-01

    Attempts once again to put to rest the infamous "I cannot tell a lie" episode involving George Washington and a downed cherry tree. Appends an editor's note that states that William Bennett's "The Children's Book of Virtues" which perpetuates this infamous piece of "fakelore." (RS)

  4. Mycotoxins in edible tree nuts.

    PubMed

    Molyneux, Russell J; Mahoney, Noreen; Kim, Jong H; Campbell, Bruce C

    2007-10-20

    Tree nuts (almonds, pistachios, and walnuts) are an exceptionally valuable crop, especially in California, with an aggregate value approaching $3.5 billion. Much of this economic value comes from overseas markets, with up to 60% of the crop being exported. The product can be contaminated with aflatoxins or ochratoxins, with the former being of special concern because of the strict regulatory levels (4 ppb total aflatoxins) applied by the European Community (EC). Natural, consumer-acceptable control methods are therefore required to conform to such limits. Research has shown that aflatoxin production is markedly decreased by the presence of natural antioxidants that occur in tree nuts, including hydrolysable tannins, flavonoids and phenolic acids. In vitro testing of individual compounds showed that the antiaflatoxigenic effect correlated with the structure and concentration of such compounds in individual nut varieties and species. This lead to the hypothesis that aflatoxin biosynthesis is stimulated by oxidative stress on the fungus and that compounds capable of relieving oxidative stress should therefore suppress or eliminate aflatoxin biosynthesis. Oxidative stress induced in A. flavus by addition of tert-butyl hydroperoxide to the media stimulated peak aflatoxin production and maintained high levels over time. However, aflatoxin formation was significantly inhibited by incorporation into the media of the antioxidant, tannic acid. Measures to increase natural products with antioxidant properties in tree nuts may thereby reduce or eliminate the ability of A. flavus to biosynthesize aflatoxins, thus ensuring levels at or below regulatory limits and maintaining export markets for U.S. tree nuts.

  5. Can Children Read Evolutionary Trees?

    ERIC Educational Resources Information Center

    Ainsworth, Shaaron; Saffer, Jessica

    2013-01-01

    Representations of the "tree of life" such as cladograms show the history of lineages and their relationships. They are increasingly found in formal and informal learning settings. Unfortunately, there is evidence that these representations can be challenging to interpret correctly. This study explored the question of whether children…

  6. Reclamation with trees in Illinois

    Treesearch

    Brad Evilsizer

    1980-01-01

    Thru private initiative, Illinois citizens historically have invented and conducted large-scale tree planting programs, starting with hedgerow fences and farmstead windbreaks and continuing with surface mine reclamation and farm woodlands. With invaluable help from public and private scientific personnel, the old and new programs hold promise of enlargement and...

  7. Tree Seed Technology Training Course

    Treesearch

    F.T. Bonner; James A. Vozzo; W.W. Elam; S.B. Land

    1994-01-01

    This manual is intended primarily to train seed collectors, seed-plant managers, seed analysts, and nursery managers, but it can serve as a resource for any training course in forest regeneration. It includes both temperate and tropical tree species of all intended uses. The manual covers the following topics: seed biology, seed collection, seed handling, seed-quality...

  8. Wellhead and tree standards updated

    SciTech Connect

    Dach, A.J. Jr.; Haeberle, T.

    1996-03-11

    Revisions in the API 6A, 17th Edition, have resolved a number of long-term problems and expanded its scope and coverage of wellhead and christmas tree equipment. The 17th Edition, Feb. 1, 1996, represents the state-of-the-art in international requirements for wellhead and christmas tree equipment. The design, materials, and quality control aspects of API 6A have all been improved with an emphasis on making the document more acceptable around the world. However, there are unresolved issues that raise many questions about the future direction of efforts aimed at international standardization of wellhead and christmas tree equipment. Unfortunately, these unresolved issues confuse both manufacturers and companies purchasing this equipment. This ultimately increases wellhead and christmas tree costs, so it is to everyone`s advantage to resolve these issues. This article describes the significant revisions that are included in API 6A, 17th Edition. Also discussed are the regulatory, standardization, and customer acceptance issues that cloud the future of API 6A, 17th Edition.

  9. Well christmas tree guard apparatus

    SciTech Connect

    Camos, W.M.; Doize, W.L.

    1981-11-17

    An oil or gas well christmas tree guard apparatus provides an annular guard body which is protectively secured about a bolted flanged connection of the well christmas tree, the guard so placed forming an envelope about the flanged connection and preventing access by a thief to the bolts and thus discouraging removal of the bolts from the bolted connection. The protective guard body thus prevents removal of the christmas tree from its location at the well head by theft denying access to the bolted connection which flanges the christmas tree to the remainder of the well. In the preferred embodiment the guard body provides a pair of annular shroud halves which are hingedly connected allowing them to be pivotally moved from an outer position allowing removal from the flanged connection to an inner closed operative position providing an overall annular guard body which is latched into position about the desired bolted connection. The guard body hinge as well as the latch structure can be protectively covered by a connected shroud or housing about the latch structure, or the hinge respectively.

  10. Transport on randomly evolving trees

    NASA Astrophysics Data System (ADS)

    Pál, L.

    2005-11-01

    The time process of transport on randomly evolving trees is investigated. By introducing the notions of living and dead nodes, a model of random tree evolution is constructed which describes the spreading in time of objects corresponding to nodes. It is assumed that at t=0 the tree consists of a single living node (root), from which the evolution may begin. At a certain time instant τ⩾0 , the root produces ν⩾0 living nodes connected by lines to the root which becomes dead at the moment of the offspring production. In the evolution process each of the new living nodes evolves further like a root independently of the others. By using the methods of the age-dependent branching processes we derive the joint distribution function of the numbers of living and dead nodes, and determine the correlation between these node numbers as a function of time. It is proved that the correlation function converges to 3/2 independently of the distributions of ν and τ when q1→1 and t→∞ . Also analyzed are the stochastic properties of the end nodes; and the correlation between the numbers of living and dead end nodes is shown to change its character suddenly at the very beginning of the evolution process. The survival probability of random trees is investigated and expressions are derived for this probability.

  11. Not Just a Fall Tree

    ERIC Educational Resources Information Center

    Miller-Hewes, Kathy A.

    2004-01-01

    Trees burst with color in the northern states. Autumn leaves dust the ground. Painting the fall landscape is nothing new. Teachers have been doing it in classrooms for decades. The approach, however, can make the difference between whether the fall landscape is simply painting for fun, or a real learning experience. Students learn best when they…

  12. Transport on randomly evolving trees.

    PubMed

    Pál, L

    2005-11-01

    The time process of transport on randomly evolving trees is investigated. By introducing the notions of living and dead nodes, a model of random tree evolution is constructed which describes the spreading in time of objects corresponding to nodes. It is assumed that at t=0 the tree consists of a single living node (root), from which the evolution may begin. At a certain time instant tau> or =0, the root produces v> or =0 living nodes connected by lines to the root which becomes dead at the moment of the offspring production. In the evolution process each of the new living nodes evolves further like a root independently of the others. By using the methods of the age-dependent branching processes we derive the joint distribution function of the numbers of living and dead nodes, and determine the correlation between these node numbers as a function of time. It is proved that the correlation function converges to square root of 3/2 independently of the distributions of v and tau when q1-->1 and t-->infinity. Also analyzed are the stochastic properties of the end nodes; and the correlation between the numbers of living and dead end nodes is shown to change its character suddenly at the very beginning of the evolution process. The survival probability of random trees is investigated and expressions are derived for this probability.

  13. The Tree of Animal Life

    ERIC Educational Resources Information Center

    Braude, Stan

    2007-01-01

    In this article, the author describes a short activity which introduces third- to fifth-grade students to animal classification. The Tree of Animal Life activity is a simple, sorting exercise that can help them see a bigger picture. The activity sets the stage for learning about animal taxonomy and introduces the characteristics of various animal…

  14. Not Just a Fall Tree

    ERIC Educational Resources Information Center

    Miller-Hewes, Kathy A.

    2004-01-01

    Trees burst with color in the northern states. Autumn leaves dust the ground. Painting the fall landscape is nothing new. Teachers have been doing it in classrooms for decades. The approach, however, can make the difference between whether the fall landscape is simply painting for fun, or a real learning experience. Students learn best when they…

  15. Trees of Our National Forests.

    ERIC Educational Resources Information Center

    Forest Service (USDA), Washington, DC.

    Presented is a description of the creation of the National Forests system, how trees grow, managing the National Forests, types of management systems, and managing for multiple use, including wildlife, water, recreation and other uses. Included are: (1) photographs; (2) line drawings of typical leaves, cones, flowers, and seeds; and (3)…

  16. Tree improvement and environmental forestry

    Treesearch

    Warren T. Doolittle

    1971-01-01

    I was invited to talk to you about some of the things tree improvement can do to help our forest environment. Now I do not claim to have a corner on the market for ideas that geneticists can use in our environment, and I know that a number of scholarly papers have been presented previously on this subject.

  17. Eucalyptus as a landscape tree

    Treesearch

    W. Douglas Hamilton

    1983-01-01

    Ninety-two species of Eucalyptus were evaluated at the University of California re- search station in San Jose. The purpose: to find acceptable new street and park trees. Growth rates and horticultural characteristics were noted. Forty-three species were studied in locations statewide to evaluate site adaptation and landscape usefulness; flooded, cold, dry, saline....

  18. Tree value conversion standards revisited

    Treesearch

    Paul S. DeBald; Martin E. Dale; Martin E. Dale

    1991-01-01

    Updated tree value conversion standards (TVCS) are presented for 12 important hardwood species of the oak-hickory forest. These updated standards-developed for each species by butt-log grade, merchantable height, and diameter at breast height-reflect the changes in lumber prices and in conversion costs which have occurred since 1976 when the original TVCS were...

  19. Enzyme polymorphism in forest trees

    Treesearch

    M. T. Conkle

    1974-01-01

    In studies of genetic differences among trees, forest biologists have found that variations fall into two categories. In the first, characterized by metric traits, the phenotypic response results from the combined activity of many genes having minor effects. In the other, characterized by mutants and some resin and disease resistance factors, the phenotypic response...

  20. The Tree of Animal Life

    ERIC Educational Resources Information Center

    Braude, Stan

    2007-01-01

    In this article, the author describes a short activity which introduces third- to fifth-grade students to animal classification. The Tree of Animal Life activity is a simple, sorting exercise that can help them see a bigger picture. The activity sets the stage for learning about animal taxonomy and introduces the characteristics of various animal…

  1. The Tree of Life Project

    ERIC Educational Resources Information Center

    Milbrath, Sherry

    2009-01-01

    Middle-school students are just beginning to recognize their place in the world. That is why this author believes it is important to incorporate their world into their art. In this article, the author discusses the "Tree of Life" project, which she developed for her students in order to make them aware of various environmental issues, and how to…

  2. The Education of Little Tree.

    ERIC Educational Resources Information Center

    Carter, Forrest

    First published in 1976, this autobiography contains Forrest Carter's--Little Tree's--remembrances of life with his Eastern Cherokee Hill country grandparents in the 1930s. There are 21 chapters, recounting humorous and serious episodes from a 5-year period and dealing with the themes of growing up, Indian life and values, family relationships,…

  3. Trees of Our National Forests.

    ERIC Educational Resources Information Center

    Forest Service (USDA), Washington, DC.

    Presented is a description of the creation of the National Forests system, how trees grow, managing the National Forests, types of management systems, and managing for multiple use, including wildlife, water, recreation and other uses. Included are: (1) photographs; (2) line drawings of typical leaves, cones, flowers, and seeds; and (3)…

  4. GumTree: Data reduction

    NASA Astrophysics Data System (ADS)

    Rayner, Hugh; Hathaway, Paul; Hauser, Nick; Fei, Yang; Franceschini, Ferdi; Lam, Tony

    2006-11-01

    Access to software tools for interactive data reduction, visualisation and analysis during a neutron scattering experiment enables instrument users to make informed decisions regarding the direction and success of their experiment. ANSTO aims to enhance the experiment experience of its facility's users by integrating these data reduction tools with the instrument control interface for immediate feedback. GumTree is a software framework and application designed to support an Integrated Scientific Experimental Environment, for concurrent access to instrument control, data acquisition, visualisation and analysis software. The Data Reduction and Analysis (DRA) module is a component of the GumTree framework that allows users to perform data reduction, correction and basic analysis within GumTree while an experiment is running. It is highly integrated with GumTree, able to pull experiment data and metadata directly from the instrument control and data acquisition components. The DRA itself uses components common to all instruments at the facility, providing a consistent interface. It features familiar ISAW-based 1D and 2D plotting, an OpenGL-based 3D plotter and peak fitting performed by fityk. This paper covers the benefits of integration, the flexibility of the DRA module, ease of use for the interface and audit trail generation.

  5. Compartmentalization of Decay in Trees.

    ERIC Educational Resources Information Center

    Shigo, Alex L.

    1985-01-01

    Unlike animals, which heal, trees compartmentalize by setting boundaries that resist the spread of invading microorganisms. Discusses the creation of new walls by anatomical and chemical means in response to death of a branch or pruning. Points out that genetic control of compartmentalization has resulted from evolution of resistant species. (DH)

  6. Can Children Read Evolutionary Trees?

    ERIC Educational Resources Information Center

    Ainsworth, Shaaron; Saffer, Jessica

    2013-01-01

    Representations of the "tree of life" such as cladograms show the history of lineages and their relationships. They are increasingly found in formal and informal learning settings. Unfortunately, there is evidence that these representations can be challenging to interpret correctly. This study explored the question of whether children…

  7. Key for Trees of Iowa.

    ERIC Educational Resources Information Center

    Coder, Kim D.; Wray, Paul H.

    This key is designed to help identify the most common trees found in Iowa. It is based on vegetative characteristics such as leaves, fruits, and bark and is illustrated with black and white line drawings. Since vegetative characteristics vary due to climate, age, soil fertility, and other conditions, the numerical sizes listed, such as length and…

  8. Statistical methods for evolutionary trees.

    PubMed

    Edwards, A W F

    2009-09-01

    In 1963 and 1964, L. L. Cavalli-Sforza and A. W. F. Edwards introduced novel methods for computing evolutionary trees from genetical data, initially for human populations from blood-group gene frequencies. The most important development was their introduction of statistical methods of estimation applied to stochastic models of evolution.

  9. Insects affecting hardwood tree plantings

    Treesearch

    Bradley D. Barnd; Paula M. Pijut; Matthew D. Ginzel

    2008-01-01

    The Central Hardwood Region (CHR) is one of the largest forested areas in the country, covering more than 100 million acres, and is dominated by oakhickory and mixed hardwoods. Although large areas of forest have been cleared to make way for agriculture and urban growth, the number of trees in the CHR is increasing as farm and pasture lands are reverting back to forest...

  10. The Tree of Life Project

    ERIC Educational Resources Information Center

    Milbrath, Sherry

    2009-01-01

    Middle-school students are just beginning to recognize their place in the world. That is why this author believes it is important to incorporate their world into their art. In this article, the author discusses the "Tree of Life" project, which she developed for her students in order to make them aware of various environmental issues, and how to…

  11. 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.

  12. Ecology: Drought and dead trees

    Treesearch

    Richard Birdsey; Yude. Pan

    2011-01-01

    Drought has emerged as a major threat to the world's forests. A study shows that tree mortality in Canada's boreal forests has increased by nearly 5% per year—much higher than expected—owing to water stress from regional warming.

  13. The Education of Little Tree.

    ERIC Educational Resources Information Center

    Carter, Forrest

    First published in 1976, this autobiography contains Forrest Carter's--Little Tree's--remembrances of life with his Eastern Cherokee Hill country grandparents in the 1930s. There are 21 chapters, recounting humorous and serious episodes from a 5-year period and dealing with the themes of growing up, Indian life and values, family relationships,…

  14. Chopping Down the Cherry Tree.

    ERIC Educational Resources Information Center

    Griswold, Jerry

    1995-01-01

    Attempts once again to put to rest the infamous "I cannot tell a lie" episode involving George Washington and a downed cherry tree. Appends an editor's note that states that William Bennett's "The Children's Book of Virtues" which perpetuates this infamous piece of "fakelore." (RS)

  15. Tree species, tree genotypes and tree genotypic diversity levels affect microbe-mediated soil ecosystem functions in a subtropical forest

    PubMed Central

    Purahong, Witoon; Durka, Walter; Fischer, Markus; Dommert, Sven; Schöps, Ricardo; Buscot, François; Wubet, Tesfaye

    2016-01-01

    Tree species identity and tree genotypes contribute to the shaping of soil microbial communities. However, knowledge about how these two factors influence soil ecosystem functions is still lacking. Furthermore, in forest ecosystems tree genotypes co-occur and interact with each other, thus the effects of tree genotypic diversity on soil ecosystem functions merit attention. Here we investigated the effects of tree species, tree genotypes and genotypic diversity levels, alongside soil physicochemical properties, on the overall and specific soil enzyme activity patterns. Our results indicate that tree species identity, tree genotypes and genotypic diversity level have significant influences on overall and specific soil enzyme activity patterns. These three factors influence soil enzyme patterns partly through effects on soil physicochemical properties and substrate quality. Variance partitioning showed that tree species identity, genotypic diversity level, pH and water content all together explained ~30% variations in the overall patterns of soil enzymes. However, we also found that the responses of soil ecosystem functions to tree genotypes and genotypic diversity are complex, being dependent on tree species identity and controlled by multiple factors. Our study highlights the important of inter- and intra-specific variations in tree species in shaping soil ecosystem functions in a subtropical forest. PMID:27857198

  16. Tree species, tree genotypes and tree genotypic diversity levels affect microbe-mediated soil ecosystem functions in a subtropical forest.

    PubMed

    Purahong, Witoon; Durka, Walter; Fischer, Markus; Dommert, Sven; Schöps, Ricardo; Buscot, François; Wubet, Tesfaye

    2016-11-18

    Tree species identity and tree genotypes contribute to the shaping of soil microbial communities. However, knowledge about how these two factors influence soil ecosystem functions is still lacking. Furthermore, in forest ecosystems tree genotypes co-occur and interact with each other, thus the effects of tree genotypic diversity on soil ecosystem functions merit attention. Here we investigated the effects of tree species, tree genotypes and genotypic diversity levels, alongside soil physicochemical properties, on the overall and specific soil enzyme activity patterns. Our results indicate that tree species identity, tree genotypes and genotypic diversity level have significant influences on overall and specific soil enzyme activity patterns. These three factors influence soil enzyme patterns partly through effects on soil physicochemical properties and substrate quality. Variance partitioning showed that tree species identity, genotypic diversity level, pH and water content all together explained ~30% variations in the overall patterns of soil enzymes. However, we also found that the responses of soil ecosystem functions to tree genotypes and genotypic diversity are complex, being dependent on tree species identity and controlled by multiple factors. Our study highlights the important of inter- and intra-specific variations in tree species in shaping soil ecosystem functions in a subtropical forest.

  17. Tree species, tree genotypes and tree genotypic diversity levels affect microbe-mediated soil ecosystem functions in a subtropical forest

    NASA Astrophysics Data System (ADS)

    Purahong, Witoon; Durka, Walter; Fischer, Markus; Dommert, Sven; Schöps, Ricardo; Buscot, François; Wubet, Tesfaye

    2016-11-01

    Tree species identity and tree genotypes contribute to the shaping of soil microbial communities. However, knowledge about how these two factors influence soil ecosystem functions is still lacking. Furthermore, in forest ecosystems tree genotypes co-occur and interact with each other, thus the effects of tree genotypic diversity on soil ecosystem functions merit attention. Here we investigated the effects of tree species, tree genotypes and genotypic diversity levels, alongside soil physicochemical properties, on the overall and specific soil enzyme activity patterns. Our results indicate that tree species identity, tree genotypes and genotypic diversity level have significant influences on overall and specific soil enzyme activity patterns. These three factors influence soil enzyme patterns partly through effects on soil physicochemical properties and substrate quality. Variance partitioning showed that tree species identity, genotypic diversity level, pH and water content all together explained ~30% variations in the overall patterns of soil enzymes. However, we also found that the responses of soil ecosystem functions to tree genotypes and genotypic diversity are complex, being dependent on tree species identity and controlled by multiple factors. Our study highlights the important of inter- and intra-specific variations in tree species in shaping soil ecosystem functions in a subtropical forest.

  18. Ice Nuclei from Birch Trees

    NASA Astrophysics Data System (ADS)

    Felgitsch, Laura; Seifried, Teresa; Winkler, Philipp; Schmale, David, III; Grothe, Hinrich

    2017-04-01

    While the importance of heterogeneous ice nucleation in the atmosphere is known, we still know very little about the substances triggering these freezing events. Recent findings support the theory that biological ice nuclei (IN) exhibit the ability to play an important role in these processes. Huffman et al. (2013) showed a burst of biological IN over woodlands triggered by rain events. Birch pollen are known to release a high number of efficient IN if incubated in water (Pummer et al. 2012). Therefore birches are of interest in our research on this topic. Plants native to the timberline, such as birch trees, have to cope with very cold climatic conditions, rendering freezing avoidance impossible. These plants trigger freezing in their extracellular spaces to control the freezing process and avoid intracellular freezing, which would have lethal consequences. The plants hereby try to freeze at a temperature well above homogeneous freezing temperatures but still at temperatures low enough to not be effected by brief night frosts. To achieve this, IN are an important tool. The specific objective of our work was to study the potential sources and distribution of IN in birch trees. We collected leaves, fruit, bark, and trunk cores from a series of mature birch trees in Tyrol, Austria at different altitudes and sampling sites. We also collected samples from a birch tree in an urban park in Vienna, Austria. Our data show a sampling site dependence and the distribution of IN throughout the tree. Our data suggest that leaves, bark, and wood of birch can function as a source of IN, which are easily extracted with water. The IN are therefore not restricted to pollen. Hence, the amount of IN, which can be released from birch trees, is tremendous and has been underrated so far. Future work aims to elucidate the nature, contribution, and potential ecological roles of IN from birch trees in different habitats. Huffman, J.A., Prenni, A.J., DeMott, P.J., Pöhlker, C., Mason, R

  19. Bayesian Evidence Framework for Decision Tree Learning

    NASA Astrophysics Data System (ADS)

    Chatpatanasiri, Ratthachat; Kijsirikul, Boonserm

    2005-11-01

    This work is primary interested in the problem of, given the observed data, selecting a single decision (or classification) tree. Although a single decision tree has a high risk to be overfitted, the induced tree is easily interpreted. Researchers have invented various methods such as tree pruning or tree averaging for preventing the induced tree from overfitting (and from underfitting) the data. In this paper, instead of using those conventional approaches, we apply the Bayesian evidence framework of Gull, Skilling and Mackay to a process of selecting a decision tree. We derive a formal function to measure `the fitness' for each decision tree given a set of observed data. Our method, in fact, is analogous to a well-known Bayesian model selection method for interpolating noisy continuous-value data. As in regression problems, given reasonable assumptions, this derived score function automatically quantifies the principle of Ockham's razor, and hence reasonably deals with the issue of underfitting-overfitting tradeoff.

  20. ScripTree: scripting phylogenetic graphics.

    PubMed

    Chevenet, François; Croce, Olivier; Hebrard, Maxime; Christen, Richard; Berry, Vincent

    2010-04-15

    There is a large amount of tools for interactive display of phylogenetic trees. However, there is a shortage of tools for the automation of tree rendering. Scripting phylogenetic graphics would enable the saving of graphical analyses involving numerous and complex tree handling operations and would allow the automation of repetitive tasks. ScripTree is a tool intended to fill this gap. It is an interpreter to be used in batch mode. Phylogenetic graphics instructions, related to tree rendering as well as tree annotation, are stored in a text file and processed in a sequential way. ScripTree can be used online or downloaded at www.scriptree.org, under the GPL license. ScripTree, written in Tcl/Tk, is a cross-platform application available for Windows and Unix-like systems including OS X. It can be used either as a stand-alone package or included in a bioinformatic pipeline and linked to a HTTP server.

  1. Secondhand Trees, Firsthand Learning. Holiday Evergreens Revitalized.

    ERIC Educational Resources Information Center

    Graves, C. John

    1990-01-01

    Described is an activity that uses discarded evergreen trees from Christmas. Tree age and growth characteristics are investigated by looking at the number of whorls and rings of the trunks. Extensions and follow-up activities are included. (KR)

  2. Pressure Apparatus for Injecting Chemicals into Trees

    Treesearch

    T. H. Filer

    1973-01-01

    A new pressure injector for forcing liquid fungicides, insecticides, or fertilizers into trees is light weight and can be installed on a tree in less than 10 minutes. Materials to build it cost approximately $12.00.

  3. More Lake States Tree Survival Predictions

    Treesearch

    Roland G. Buchman; Ellen L. Lentz

    1984-01-01

    Species coefficients are reported for predicting individual tree survival for nine Lake States species, supplementing a previous report for 10 species. Tree attributes are diameter growth rate and diameter at breast height. Regional and local performances are summarized.

  4. Isoprene emission from Indian trees

    NASA Astrophysics Data System (ADS)

    Varshney, C. K.; Singh, Abhai Pratap

    2003-12-01

    Isoprene is the most dominant non-methane volatile organic compound (NMVOC) emitted by plants. NMVOCs play an important role in regulating the composition of atmospheric trace gases including global concentration of tropospheric ozone. Our present knowledge about NMVOCs emission is mainly from studies on temperate tree species. So far information on biogenic NMVOCs emission from tropical tree species is limited. In this study, isoprene emission rates from 40 tropical Indian tree species belonging to 33 genera and 17 families were measured for the first time using a dynamic flow through enclosure chamber technique. The isoprene emission rate from plants (30°C and PAR 1000 μmolm-2s-1) ranged from undetectable to 81.5 μg g-1 h-1 and values were found to be comparable with other studies on tropical tree species. Tree species screened for isoprene emission in the present study may be grouped into the four categories, proposed by [2001], namely, 18 species were negligible or BDL isoprene emitting (<1 μg g-1 h-1), 6 species were low emitting (1 ≤ to <10 μg g-1 h-1), 5 species were moderate emitting (10≤ to <25 μg g-1 h-1), and 11 species were high isoprene emitting (≥25 μg g-1 h-1). Maximum isoprene emission rate (81.5 μg g-1 h-1) was observed in the case of Dalbergia sissoo Linn. It was interesting to find that Citrus limon Linn., Citrus reticulata Linn., Citrus sinensis Linn., Grevillea robusta A. Cunn., and Morus alba Linn., which were earlier reported as BDL or non isoprene emitters in US [, 1998; , 2001] were found to be appreciably high isoprene emitters (0.61-21.60 μg g-1 h-1) in the present study.

  5. Methane Emissions from Deciduous Trees

    NASA Astrophysics Data System (ADS)

    Rice, A. L.; Teama, D.; Khalil, M. K.; Shearer, M. J.; Rosenstiel, T. N.

    2008-12-01

    There is some disagreement today over whether terrestrial plants present a significant source of methane to the atmosphere. Even if the plants are recognized as a source, there is no clear method to extrapolate plant emissions to the global atmospheric budget of methane and estimates vary widely. There is also no consensus on a mechanism for methane production and/or plant-mediated transport to the atmosphere. Here, we present preliminary data showing a significant flux of methane to the atmosphere from three wetland deciduous tree species. Ash (Fraxinus latifolia), cottonwood (Populus deltoides L.), and willow (Salix fluviatillis) were grown in a greenhouse under inundated rice-cultivation conditions using a rice straw amendment equivalent to 3 t/ha to enhance below ground anaerobic methane production. Results of measurements of redox potential and methane concentrations in soil pore water show significant methane production similar to that observed in rice plots (Oryza sative L. 'M-103') and controls of the same treatment. Measurements of the stable carbon isotopic composition (δ13C) of methane dissolved in soil pore water show no significant difference from rice plots showing no discernable difference in bulk carbon substrate. Methane flux from trees, measured using static flux chamber and bag-tree enclosures, was found to be significantly higher than control treatments (i.e., no plants) but lower than rice plants overall. The carbon isotopic composition of emitted methane from tree species was found to be approximately 8‰ enriched in δ13C compared with methane emitted from rice. This difference in δ13C of emitted methane observed between rice and trees suggests the mechanisms contributing to regulating plant-mediated methane transport (e.g. transport, oxidation, carbon sources) may be quite distinct between diverse plant functional types. Identifying the mechanistic basis of this response will be a key development towards developing more accurate estimates

  6. Northern Mountain and Prairie Community Tree Guide

    Treesearch

    E.G. McPherson; J.R. Simpson; P.J. Peper; S.E. Maco; Q. Xiao; P.J. Hoefer

    2003-01-01

    This tree guide quantifies benefits and costs for typical large-, medium-, small-stature, deciduous trees, as well as a conifer. The analysis assumed that trees were planted in a residential yard site or a public (street/park) site, under a 40-year time frame, and having a 60% survival rate. Tree care costs were based on findings from a survey of municipal and...

  7. The national tree-list layer

    Treesearch

    Stacy A. Drury; Jason M. Herynk

    2011-01-01

    The National Tree-List Layer (NTLL) project used LANDFIRE map products to produce the first national tree-list map layer that represents tree populations at stand and regional levels. The NTLL was produced in a short time frame to address the needs of Fire and Aviation Management for a map layer that could be used as input for simulating fire-caused tree mortality...

  8. Recovery efficiency of whole-tree harvesting

    Treesearch

    Bryce J. Stokes; William F. Watson

    1988-01-01

    The recovery of total tree biomass and most components of a stand is a practical economic and management alternative to tree-length harvesting. First, the increased utilization of woody biomass provides additional revenues from the site. Second, the removal and utilization of the stems and crowns reduces site preparation costs and makes tree planting easier. Third,...

  9. A Multipurpose Tree for Puerto Rico

    Treesearch

    Martin Chudnoff; C. B. Briscoe

    1965-01-01

    Cadam (Anthocaephalus cadamba Miq.) grows very rapidly on a wide variety of sited in Puerto Rico. Tree form is excellent, seed is produced in abundance every year by mature trees, planting is easy and cheap, and relatively little care is required after planting. No important attacks of insects of disease have occurred on trees grown in Puerto Rico for 35 years. The...

  10. Evaluating realized genetic gains from tree improvement.

    Treesearch

    J.B. St. Clair

    1993-01-01

    Tree improvement has become an essential part of the management of forest lands for wood production, and predicting yields and realized gains from forests planted with genetically-improved trees will become increasingly important. This paper discusses concepts of tree improvement and genetic gain important to growth and yield modeling, and reviews previous studies of...

  11. Do you believe in palm trees?

    Treesearch

    Kevin T. Smith

    2013-01-01

    Palms are real, but are they really trees? The answer depends on definitions. As usually tall, peremrial plants with roots, stems, and leaves, palms seem to qualify. Palms should also qualify because arborists care for them, and arborists care for trees, right? My introduction to botany class defined trees as plants that produce wood. Unraveling the question of whether...

  12. Carbon dynamics in trees: feast or famine?

    Treesearch

    Anna Sala; David R. Woodruff; Fredrick C. Meinzer

    2012-01-01

    Research on the degree to which carbon (C) availability limits growth in trees, as well as recent trends in climate change and concurrent increases in drought related tree mortality, have led to a renewed focus on the physiological mechanisms associated with tree growth responses to current and future climate. This has led to some dispute over the role of stored...

  13. HOW to Recognize Hazardous Defects in Trees

    Treesearch

    Minnesota Department of Natural Resources; USDA Forest Service

    1996-01-01

    Trees add to our enjoyment of outdoor experiences whether in forests, parks, or urban landscapes. Too often, we are unaware of the risks associated with defective trees, which can cause personal injury and property damage. Interest in hazard tree management has increased in recent years due to safety and liability concerns resulting from preventable accidents....

  14. 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...

  15. A practical alternative to single tree selection?

    Treesearch

    Gary W. Miller; H. Clay Smith

    1993-01-01

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

  16. Does predation contribute to tree diversity?

    Treesearch

    Brian Beckage; James S. Clark

    2005-01-01

    Seed and seedling predation may differentially affect competitively superior tree species to increase the relative recruitment success of poor competitors and contribute to the coexistence of tree species. We examined the effect of seed and seedling predation on the seedling recruitment of three tree species, Acer rubrum (red maple), ...

  17. 7 CFR 1214.3 - Christmas tree.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 10 2014-01-01 2014-01-01 false Christmas tree. 1214.3 Section 1214.3 Agriculture... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE CHRISTMAS TREE PROMOTION, RESEARCH, AND INFORMATION ORDER Christmas Tree Promotion, Research, and Information Order Definitions § 1214.3...

  18. 7 CFR 1214.3 - Christmas tree.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 10 2013-01-01 2013-01-01 false Christmas tree. 1214.3 Section 1214.3 Agriculture... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE CHRISTMAS TREE PROMOTION, RESEARCH, AND INFORMATION ORDER Christmas Tree Promotion, Research, and Information Order Definitions § 1214.3...

  19. 7 CFR 1214.3 - Christmas tree.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 10 2012-01-01 2012-01-01 false Christmas tree. 1214.3 Section 1214.3 Agriculture... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE CHRISTMAS TREE PROMOTION, RESEARCH, AND INFORMATION ORDER Christmas Tree Promotion, Research, and Information Order Definitions § 1214.3...

  20. Oak Tree Preservation in Thousand Oaks, California

    Treesearch

    William F. Elmendorf

    1991-01-01

    The City of Thousand Oaks over the last 20 years has taken aggressive steps to preserve and protect the City's namesake, the oak tree. First adopted in 1972 as an Emergency City Council Proclamation, the City's Oak Tree Ordinance has been considered by some, to be one of the first and toughest municipal native tree preservation ordinances within the State of...

  1. Tree biomass in the North Central Region.

    Treesearch

    Gerhard K. Raile; Pamela J. Jakes

    1982-01-01

    Methods for calculating tree biomass are outlined, and the biomass on commercial forest land is estimated for 11 north-central states. Tree biomass in the North Central Region totals 3.6 billion tons, or 50 tons per commercial forest acre. For all species, total tree biomass is concentrated in growing-stock boles.

  2. Big trees in the southern forest inventory

    Treesearch

    Christopher M. Oswalt; Sonja N. Oswalt; Thomas J. Brandeis

    2010-01-01

    Big trees fascinate people worldwide, inspiring respect, awe, and oftentimes, even controversy. This paper uses a modified version of American Forests’ Big Trees Measuring Guide point system (May 1990) to rank trees sampled between January of 1998 and September of 2007 on over 89,000 plots by the Forest Service, U.S. Department of Agriculture, Forest Inventory and...

  3. Canopy cover estimates for individual tree attributes

    Treesearch

    James A. Westfall; Randall S. Morin

    2012-01-01

    In most forest inventory data, it is not feasible to estimate the canopy coverage of trees having certain characteristics due to the lack of information on crown size. In this study, data from the Forest Inventory and Analysis (FIA) program was used to assign crown sizes to individual trees using published crown width models. This process effectively links trees to...

  4. Tree planting: not a simple solution

    Treesearch

    Constance I. Millar; William J. Libby

    1991-01-01

    There's no doubt about it. Planting trees has caught the attention of the American public. In his 1990 State of the Union address, President Bush proposed planting a billion Fees annually for the next ten years. Inspired by the potential for trees to reduce greenhouse gases and mitigate global climate change, tree-planting programs such as Treepeople and Global...

  5. 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...

  6. Mathematical form models of tree trunks

    Treesearch

    Rudolfs Ozolins

    2000-01-01

    Assortment structure analysis of tree trunks is a characteristic and proper problem that can be solved by using mathematical modeling and standard computer programs. Mathematical form model of tree trunks consists of tapering curve equations and their parameters. Parameters for nine species were obtained by processing measurements of 2,794 model trees and studying the...

  7. Simplifying gene trees for easier comprehension

    PubMed Central

    Lott, Paul-Ludwig; Mundry, Marvin; Sassenberg, Christoph; Lorkowski, Stefan; Fuellen, Georg

    2006-01-01

    Background In the genomic age, gene trees may contain large amounts of data making them hard to read and understand. Therefore, an automated simplification is important. Results We present a simplification tool for gene trees called TreeSimplifier. Based on species tree information and HUGO gene names, it summarizes "monophyla". These monophyla correspond to subtrees of the gene tree where the evolution of a gene follows species phylogeny, and they are simplified to single leaves in the gene tree. Such a simplification may fail, for example, due to genes in the gene tree that are misplaced. In this way, misplaced genes can be identified. Optionally, our tool glosses over a limited degree of "paraphyly" in a further simplification step. In both simplification steps, species can be summarized into groups and treated as equivalent. In the present study we used our tool to derive a simplified tree of 397 leaves from a tree of 1138 leaves. Comparing the simplified tree to a "cartoon tree" created manually, we note that both agree to a high degree. Conclusion Our automatic simplification tool for gene trees is fast, accurate, and effective. It yields results of similar quality as manual simplification. It should be valuable in phylogenetic studies of large protein families. The software is available at . PMID:16643669

  8. Simplifying gene trees for easier comprehension.

    PubMed

    Lott, Paul-Ludwig; Mundry, Marvin; Sassenberg, Christoph; Lorkowski, Stefan; Fuellen, Georg

    2006-04-27

    In the genomic age, gene trees may contain large amounts of data making them hard to read and understand. Therefore, an automated simplification is important. We present a simplification tool for gene trees called TreeSimplifier. Based on species tree information and HUGO gene names, it summarizes "monophyla". These monophyla correspond to subtrees of the gene tree where the evolution of a gene follows species phylogeny, and they are simplified to single leaves in the gene tree. Such a simplification may fail, for example, due to genes in the gene tree that are misplaced. In this way, misplaced genes can be identified. Optionally, our tool glosses over a limited degree of "paraphyly" in a further simplification step. In both simplification steps, species can be summarized into groups and treated as equivalent. In the present study we used our tool to derive a simplified tree of 397 leaves from a tree of 1138 leaves. Comparing the simplified tree to a "cartoon tree" created manually, we note that both agree to a high degree. Our automatic simplification tool for gene trees is fast, accurate, and effective. It yields results of similar quality as manual simplification. It should be valuable in phylogenetic studies of large protein families. The software is available at http://www.uni-muenster.de/Bioinformatics/services/treesim/.

  9. On estimation in k-tree sampling

    Treesearch

    Christoph Kleinn; Frantisek Vilcko

    2007-01-01

    The plot design known as k-tree sampling involves taking the k nearest trees from a selected sample point as sample trees. While this plot design is very practical and easily applied in the field for moderate values of k, unbiased estimation remains a problem. In this article, we give a brief introduction to the...

  10. New tree puller increases yield 20%

    Treesearch

    E. Kerr

    1977-01-01

    A new tree harvester that extracts both taproot and stem makes a pine tree 20 percent more useful. The machine shears the lateral roots close to the taprrot and then plucks the entire tree from the ground like a carrot. The concept was developed by Dr. Peter Koch at the U.S. Forest Service's Southern Forest Experiment Station in Pineville, La. The shearing...

  11. Sampling the quality of hardwood trees

    Treesearch

    Adrian M. Gilbert

    1959-01-01

    Anyone acquainted with the conversion of hardwood trees into wood products knows that timber has a wide range in quality. Some trees will yield better products than others. So, in addition to rate of growth and size, tree values are affected by the quality of products yielded.

  12. Tree Growth Rings: What They Tell Us.

    ERIC Educational Resources Information Center

    Sunal, Dennis W.; Sunal, Cynthia Szymanski

    1991-01-01

    Activities in which students can learn to determine the history of a tree from the growth pattern recorded in the rings of a cross-section of a tree are described. Activities include background information, objectives, a list of needed materials per group, and procedures. Cross-sections of four different tree types are included if real tree…

  13. Genomics of Tropical Fruit Tree Crops

    USDA-ARS?s Scientific Manuscript database

    The genetic improvement of tropical fruit trees is limited when compared to progress achieved in temperate fruit trees and annual crops. Tropical fruit tree breeding programs require significant resources to develop new cultivars that are adapted to modern shipping and storage requirements. The use...

  14. Big trees of the Midsouth Forest Survey

    Treesearch

    Dennis M. May

    1990-01-01

    Forestry agencies and associations across the country maintain registers of champion big trees.Listings of the biggest trees encountered on the USDA Forest Service's continuing survey of the forest lands of seven Midsouth States have been prepared.The listings report the biggest trees encountered by species for each State and the Midsouth region.These listings...

  15. Data multiplexer using a tree switch

    NASA Technical Reports Server (NTRS)

    Easton, R. A.; Hilbert, E. E.

    1973-01-01

    Self-decoding FET-hybrid or integrated-circuit tree configuration uses minimum number of components and can be sequenced by clock or computer. Redundancy features can readily be incorporated into tree configuration; as tree grows in size and more sensors are included, percentage of parts that will affect given percentage of sensors steadily decreases.

  16. Street tree pruning and removal needs

    Treesearch

    David J. Nowak

    1990-01-01

    Street tree pruning and removal needs were examined for 11 species from inventory data collected in 11 cities in the North Central and Northeastern United States. The needs ranged from predominantly no pruning and routine pruning of small trees to safety pruning and removal of large trees. Species were ranked in terms of overall pruning and removal urgency, with London...

  17. Measuring and analyzing urban tree cover

    Treesearch

    David J. Nowak; Rowan A. Rowntree; E. Gregory McPherson; Susan M. Sisinni; Esther R. Kirkmann; Jack C. Stevens

    1996-01-01

    Measurement of city tree cover can aid in urban vegetation planning, management, and research by revealing characteristics of vegetation across a city. Urban tree cover in the United States ranges from 0.4% in Lancaster, California, to 55% in Baton Rouge, Louisiana. Two important factors that affect the amount of urban tree cover are the natural environment and land...

  18. Soil temperatures under urban trees and asphalt

    Treesearch

    Howard G. Halverson; Gordon M. Heisler

    1981-01-01

    Summer temperatures under trees planted in holes cut through an asphalt cover in a parking lot and in soil beneath the surrounding asphalt were higher than soil temperatures under trees at a control site. Winter minimums were not different, but maximum summer temperature exceeded the control by 3ºC beneath the parking lot trees and up to 10ºC beneath...

  19. The '06 trap trees in '07

    Treesearch

    Andrea C. Anulewicz; Deborah G. McCullough; Therese M. Poland; David Cappaert

    2008-01-01

    To date, use of girdled trap trees remain the most effective method employed by regulatory and resource management agencies for detecting low-density populations of emerald ash borer (EAB), Agrilus planipennis Fairmaire. Locating suitable trees can be difficult, and felling and debarking trap trees is expensive. Alternative options for EAB detection...

  20. Understanding the challenges of municipal tree planting

    Treesearch

    E.G. McPherson; R. Young

    2010-01-01

    Nine of the twelve largest cities in the U.S. have mayoral tree planting initiatives (TPIs), with pledges to plant nearly 20 million trees. Although executive-level support for trees has never been this widespread, many wonder if this support will endure as administrations change and budgets tighten. In an effort to share lessons learned from successes and setbacks, a...

  1. TreeGenes and CartograTree: Enabling visualization and analysis in forest tree genomics

    Treesearch

    E.S. Grau; S.A. Demurjian; H.A. Vasquez-Gross; D.G. Gessler; D.B. Neale; J.L. Wegrzyn

    2017-01-01

    Association studies integrating environmental, phenotypic, and genetic data are key in understanding forest tree resilience to climate change and disease. As genomic resources increase, both in terms of complete reference sequences and magnitude of individuals genotyped, researchers are better equipped to identify correlations between genetic variation and adaptive or...

  2. Totally Tree-mendous Activities: Projects To Discover the Beauty and Benefits of Trees.

    ERIC Educational Resources Information Center

    Hollister, Sarah

    This teacher's guide supplies information and hands-on activities to teach about trees from several disciplines. Activities are grouped into six areas that cover botany, social studies, arts and literature (aesthetics), and trees as a resource. Sections include: (1) Tree Identification, which defines trees and leaves and presents activities that…

  3. Monitoring Million Trees LA: Tree performance during the early years and future benefits

    Treesearch

    E. Gregory. McPherson

    2014-01-01

    Million Trees LA (MTLA) is one of several large-scale mayoral tree planting initiatives striving to create more livable cities through urban forestry. This study combined field sampling of tree survival and growth with numerical modeling of future benefits to assess performance of MTLA plantings. From 2006 to 2010 MTLA planted a diverse mix of 91,786 trees....

  4. Totally Tree-mendous Activities: Projects To Discover the Beauty and Benefits of Trees.

    ERIC Educational Resources Information Center

    Hollister, Sarah

    This teacher's guide supplies information and hands-on activities to teach about trees from several disciplines. Activities are grouped into six areas that cover botany, social studies, arts and literature (aesthetics), and trees as a resource. Sections include: (1) Tree Identification, which defines trees and leaves and presents activities that…

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

    Treesearch

    Thomas B. Lynch; Robert F. Wittwer

    2002-01-01

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

  6. 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...

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

    PubMed

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

    2008-07-01

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

  8. Sleeping tree choice by Bwindi chimpanzees.

    PubMed

    Stanford, Craig B; O'Malley, Robert C

    2008-07-01

    Unlike nearly all other nonhuman primates, great apes build sleeping nests. In Bwindi Impenetrable National Park, Uganda, chimpanzees build nests nightly and also build day nests. We investigated patterns of nest tree use by Bwindi chimpanzees to understand ecological influences on nest tree selection. We analyzed data on 3,414 chimpanzee nests located from 2000 to 2004. Chimpanzees at Bwindi were selective in their use of nest trees. Of at least 163 tree species known to occur in Bwindi [Butynski, Ecological survey of the Impenetrable (Bwindi) Forest, Uganda, and recommendations for its conservation and management. Report to the Government of Uganda, 1984], chimpanzees utilized only 38 species for nesting. Of these, four tree species (Cassipourea sp., Chrysophyllum gorungosanum, Drypetes gerrardii, and Teclea nobilis) accounted for 72.1% of all nest trees. There was considerable variation in nesting frequencies among the top four species between and within years. However, these species were used significantly more often for nesting than other species in 70.9% (39 of 55) of the months of this study. A Spearman rank correlation found no significant relationship between tree abundance and tree species preference. Ninety-three percent of all nests were constructed in food tree species, although not necessarily at the same time the trees bore food items used by chimpanzees. The results indicate that nesting tree species preferences exist. Bwindi chimpanzees' choice of nesting tree species does not appear to be dependent on tree species density or use of the tree for food. We discuss possible reasons for the selectivity in nest trees by the Bwindi population.

  9. Statistical Properties of Genealogical Trees

    NASA Astrophysics Data System (ADS)

    Derrida, Bernard; Manrubia, Susanna C.; Zanette, Damián H.

    1999-03-01

    We analyze the statistical properties of genealogical trees in a neutral model of a closed population with sexual reproduction and nonoverlapping generations. By reconstructing the genealogy of an individual from the population evolution, we measure the distribution of ancestors appearing more than once in a given tree. After a transient time, the probability of repetition follows, up to a rescaling, a stationary distribution which we calculate both numerically and analytically. This distribution exhibits a universal shape with a nontrivial power law which can be understood by an exact, though simple, renormalization calculation. Some real data on human genealogy illustrate the problem, which is relevant to the study of the real degree of diversity in closed interbreeding communities.

  10. Doubling bialgebras of rooted trees

    NASA Astrophysics Data System (ADS)

    Mohamed, Mohamed Belhaj; Manchon, Dominique

    2017-01-01

    The vector space spanned by rooted forests admits two graded bialgebra structures. The first is defined by Connes and Kreimer using admissible cuts, and the second is defined by Calaque, Ebrahimi-Fard and the second author using contraction of trees. In this article, we define the doubling of these two spaces. We construct two bialgebra structures on these spaces which are in interaction, as well as two related associative products obtained by dualization. We also show that these two bialgebras verify a commutative diagram similar to the diagram verified Calaque, Ebrahimi-Fard and the second author in the case of rooted trees Hopf algebra, and by the second author in the case of cycle-free oriented graphs.

  11. Trees Outside Forest In Poland

    NASA Astrophysics Data System (ADS)

    Zajączkowski, Jacek; Zajączkowski, Kazimierz

    2015-01-01

    Increasing environmental threats to agricultural production and the stability of ecosystems have been observed on the Polish lowlands since the 1970s. Several hundred million trees and shrubs have been planted on farmland, mostly along roads and with the involvement of public agencies, with a view to timber being produced, and soil erosion and the water deficit mitigated. On the basis of over 50 years of practical observations and scientific experiments, recommendations have been drawn up as regards the structural and spatial features of new tree planting outside forests that maximize environmental, production-related and social benefits. This paper gives a brief description of the history of the active establishment of woody vegetation across agricultural landscapes in Poland, along with best practices elaborated for this at several scientific centres.

  12. Reweighting with Boosted Decision Trees

    NASA Astrophysics Data System (ADS)

    Rogozhnikov, Alex

    2016-10-01

    Machine learning tools are commonly used in modern high energy physics (HEP) experiments. Different models, such as boosted decision trees (BDT) and artificial neural networks (ANN), are widely used in analyses and even in the software triggers [1]. In most cases, these are classification models used to select the “signal” events from data. Monte Carlo simulated events typically take part in training of these models. While the results of the simulation are expected to be close to real data, in practical cases there is notable disagreement between simulated and observed data. In order to use available simulation in training, corrections must be introduced to generated data. One common approach is reweighting — assigning weights to the simulated events. We present a novel method of event reweighting based on boosted decision trees. The problem of checking the quality of reweighting step in analyses is also discussed.

  13. Small Specifications for Tree Update

    NASA Astrophysics Data System (ADS)

    Gardner, Philippa; Wheelhouse, Mark

    O'Hearn, Reynolds and Yang introduced Separation Logic to provide modular reasoning about simple, mutable data structures in memory. They were able to construct small specifications of programs, by reasoning about the local parts of memory accessed by programs. Gardner, Calcagno and Zarfaty generalised this work, introducing Context Logic to reason about more complex data structures. In particular, they developed a formal, compositional specification of the Document Object Model, a W3C XML update library. Whilst keeping to the spirit of local reasoning, they were not able to retain small specifications. We introduce Segment Logic, which provides a more fine-grained analysis of the tree structure and yields small specifications. As well as being aesthetically pleasing, small specifications are important for reasoning about concurrent tree update.

  14. Real Trees in the Classroom

    ERIC Educational Resources Information Center

    Fernandes, Francisca Maria; de Carvalho, Luis Mendonca; Silveira, Margarida

    2006-01-01

    At home, children often have pets that they take care of and play with; even in the classroom it is not uncommon to find a wormery, an aquarium or an ant farm. However, children rarely have the opportunity to own and care for a plant over a lengthy period of time, let alone a tree. The authors describe a project in Portugal aimed at improving…

  15. Real Trees in the Classroom

    ERIC Educational Resources Information Center

    Fernandes, Francisca Maria; de Carvalho, Luis Mendonca; Silveira, Margarida

    2006-01-01

    At home, children often have pets that they take care of and play with; even in the classroom it is not uncommon to find a wormery, an aquarium or an ant farm. However, children rarely have the opportunity to own and care for a plant over a lengthy period of time, let alone a tree. The authors describe a project in Portugal aimed at improving…

  16. Time series diagnosis of tree hydraulic characteristics.

    PubMed

    Phillips, Nathan G; Oren, Ram; Licata, Julian; Linder, Sune

    2004-08-01

    An in vivo method for diagnosing hydraulic characteristics of branches and whole trees is described. The method imposes short-lived perturbations of transpiration and traces the propagation of the hydraulic response through trees. The water uptake response contains the integrated signature of hydraulic resistance and capacitance within trees. The method produces large signal to noise ratios for analysis, but does not cause damage or destruction to tree stems or branches. Based on results with two conifer tree species, we show that the method allows for the simple parameterization of bulk hydraulic resistance and capacitance of trees. Bulk tree parameterization of resistance and capacitance predicted the overall diel shape of water uptake, but did not predict the overshoot water uptake response in trees to shorter-term variations in transpiration, created by step changes in transpiration rate. Stomatal dynamics likely complicated the use of simple resistance-capacitance models of tree water transport on these short time scales. The results provide insight into dominant hydraulic and physiological factors controlling tree water flux on varying time scales, and allow for the practical assessment of necessary tree hydraulic model complexity in relation to the time step of soil- vegetation-atmosphere transport models.

  17. Anatomical modeling of the bronchial tree

    NASA Astrophysics Data System (ADS)

    Hentschel, Gerrit; Klinder, Tobias; Blaffert, Thomas; Bülow, Thomas; Wiemker, Rafael; Lorenz, Cristian

    2010-02-01

    The bronchial tree is of direct clinical importance in the context of respective diseases, such as chronic obstructive pulmonary disease (COPD). It furthermore constitutes a reference structure for object localization in the lungs and it finally provides access to lung tissue in, e.g., bronchoscope based procedures for diagnosis and therapy. This paper presents a comprehensive anatomical model for the bronchial tree, including statistics of position, relative and absolute orientation, length, and radius of 34 bronchial segments, going beyond previously published results. The model has been built from 16 manually annotated CT scans, covering several branching variants. The model is represented as a centerline/tree structure but can also be converted in a surface representation. Possible model applications are either to anatomically label extracted bronchial trees or to improve the tree extraction itself by identifying missing segments or sub-trees, e.g., if located beyond a bronchial stenosis. Bronchial tree labeling is achieved using a naïve Bayesian classifier based on the segment properties contained in the model in combination with tree matching. The tree matching step makes use of branching variations covered by the model. An evaluation of the model has been performed in a leaveone- out manner. In total, 87% of the branches resulting from preceding airway tree segmentation could be correctly labeled. The individualized model enables the detection of missing branches, allowing a targeted search, e.g., a local rerun of the tree-segmentation segmentation.

  18. Hyperdominance in the Amazonian tree flora.

    PubMed

    ter Steege, Hans; Pitman, Nigel C A; Sabatier, Daniel; Baraloto, Christopher; Salomão, Rafael P; Guevara, Juan Ernesto; Phillips, Oliver L; Castilho, Carolina V; Magnusson, William E; Molino, Jean-François; Monteagudo, Abel; Núñez Vargas, Percy; Montero, Juan Carlos; Feldpausch, Ted R; Coronado, Eurídice N Honorio; Killeen, Tim J; Mostacedo, Bonifacio; Vasquez, Rodolfo; Assis, Rafael L; Terborgh, John; Wittmann, Florian; Andrade, Ana; Laurance, William F; Laurance, Susan G W; Marimon, Beatriz S; Marimon, Ben-Hur; Guimarães Vieira, Ima Célia; Amaral, Iêda Leão; Brienen, Roel; Castellanos, Hernán; Cárdenas López, Dairon; Duivenvoorden, Joost F; Mogollón, Hugo F; Matos, Francisca Dionízia de Almeida; Dávila, Nállarett; García-Villacorta, Roosevelt; Stevenson Diaz, Pablo Roberto; Costa, Flávia; Emilio, Thaise; Levis, Carolina; Schietti, Juliana; Souza, Priscila; Alonso, Alfonso; Dallmeier, Francisco; Montoya, Alvaro Javier Duque; Fernandez Piedade, Maria Teresa; Araujo-Murakami, Alejandro; Arroyo, Luzmila; Gribel, Rogerio; Fine, Paul V A; Peres, Carlos A; Toledo, Marisol; Aymard C, Gerardo A; Baker, Tim R; Cerón, Carlos; Engel, Julien; Henkel, Terry W; Maas, Paul; Petronelli, Pascal; Stropp, Juliana; Zartman, Charles Eugene; Daly, Doug; Neill, David; Silveira, Marcos; Paredes, Marcos Ríos; Chave, Jerome; Lima Filho, Diógenes de Andrade; Jørgensen, Peter Møller; Fuentes, Alfredo; Schöngart, Jochen; Cornejo Valverde, Fernando; Di Fiore, Anthony; Jimenez, Eliana M; Peñuela Mora, Maria Cristina; Phillips, Juan Fernando; Rivas, Gonzalo; van Andel, Tinde R; von Hildebrand, Patricio; Hoffman, Bruce; Zent, Eglée L; Malhi, Yadvinder; Prieto, Adriana; Rudas, Agustín; Ruschell, Ademir R; Silva, Natalino; Vos, Vincent; Zent, Stanford; Oliveira, Alexandre A; Schutz, Angela Cano; Gonzales, Therany; Trindade Nascimento, Marcelo; Ramirez-Angulo, Hirma; Sierra, Rodrigo; Tirado, Milton; Umaña Medina, María Natalia; van der Heijden, Geertje; Vela, César I A; Vilanova Torre, Emilio; Vriesendorp, Corine; Wang, Ophelia; Young, Kenneth R; Baider, Claudia; Balslev, Henrik; Ferreira, Cid; Mesones, Italo; Torres-Lezama, Armando; Urrego Giraldo, Ligia Estela; Zagt, Roderick; Alexiades, Miguel N; Hernandez, Lionel; Huamantupa-Chuquimaco, Isau; Milliken, William; Palacios Cuenca, Walter; Pauletto, Daniela; Valderrama Sandoval, Elvis; Valenzuela Gamarra, Luis; Dexter, Kyle G; Feeley, Ken; Lopez-Gonzalez, Gabriela; Silman, Miles R

    2013-10-18

    The vast extent of the Amazon Basin has historically restricted the study of its tree communities to the local and regional scales. Here, we provide empirical data on the commonness, rarity, and richness of lowland tree species across the entire Amazon Basin and Guiana Shield (Amazonia), collected in 1170 tree plots in all major forest types. Extrapolations suggest that Amazonia harbors roughly 16,000 tree species, of which just 227 (1.4%) account for half of all trees. Most of these are habitat specialists and only dominant in one or two regions of the basin. We discuss some implications of the finding that a small group of species--less diverse than the North American tree flora--accounts for half of the world's most diverse tree community.

  19. On finding minimum-diameter clique trees

    SciTech Connect

    Blair, J.R.S. . Dept. of Computer Science); Peyton, B.W. )

    1991-08-01

    It is well-known that any chordal graph can be represented as a clique tree (acyclic hypergraph, join tree). Since some chordal graphs have many distinct clique tree representations, it is interesting to consider which one is most desirable under various circumstances. A clique tree of minimum diameter (or height) is sometimes a natural candidate when choosing clique trees to be processed in a parallel computing environment. This paper introduces a linear time algorithm for computing a minimum-diameter clique tree. The new algorithm is an analogue of the natural greedy algorithm for rooting an ordinary tree in order to minimize its height. It has potential application in the development of parallel algorithms for both knowledge-based systems and the solution of sparse linear systems of equations. 31 refs., 7 figs.

  20. Tree climbing and human evolution.

    PubMed

    Venkataraman, Vivek V; Kraft, Thomas S; Dominy, Nathaniel J

    2013-01-22

    Paleoanthropologists have long argued--often contentiously--about the climbing abilities of early hominins and whether a foot adapted to terrestrial bipedalism constrained regular access to trees. However, some modern humans climb tall trees routinely in pursuit of honey, fruit, and game, often without the aid of tools or support systems. Mortality and morbidity associated with facultative arboreality is expected to favor behaviors and anatomies that facilitate safe and efficient climbing. Here we show that Twa hunter-gatherers use extraordinary ankle dorsiflexion (>45°) during climbing, similar to the degree observed in wild chimpanzees. Although we did not detect a skeletal signature of dorsiflexion in museum specimens of climbing hunter-gatherers from the Ituri forest, we did find that climbing by the Twa is associated with longer fibers in the gastrocnemius muscle relative to those of neighboring, nonclimbing agriculturalists. This result suggests that a more excursive calf muscle facilitates climbing with a bipedally adapted ankle and foot by positioning the climber closer to the tree, and it might be among the mechanisms that allow hunter-gatherers to access the canopy safely. Given that we did not find a skeletal correlate for this observed behavior, our results imply that derived aspects of the hominin ankle associated with bipedalism remain compatible with vertical climbing and arboreal resource acquisition. Our findings challenge the persistent arboreal-terrestrial dichotomy that has informed behavioral reconstructions of fossil hominins and highlight the value of using modern humans as models for inferring the limits of hominin arboreality.

  1. Tree climbing and human evolution

    PubMed Central

    Venkataraman, Vivek V.; Kraft, Thomas S.; Dominy, Nathaniel J.

    2013-01-01

    Paleoanthropologists have long argued—often contentiously—about the climbing abilities of early hominins and whether a foot adapted to terrestrial bipedalism constrained regular access to trees. However, some modern humans climb tall trees routinely in pursuit of honey, fruit, and game, often without the aid of tools or support systems. Mortality and morbidity associated with facultative arboreality is expected to favor behaviors and anatomies that facilitate safe and efficient climbing. Here we show that Twa hunter–gatherers use extraordinary ankle dorsiflexion (>45°) during climbing, similar to the degree observed in wild chimpanzees. Although we did not detect a skeletal signature of dorsiflexion in museum specimens of climbing hunter–gatherers from the Ituri forest, we did find that climbing by the Twa is associated with longer fibers in the gastrocnemius muscle relative to those of neighboring, nonclimbing agriculturalists. This result suggests that a more excursive calf muscle facilitates climbing with a bipedally adapted ankle and foot by positioning the climber closer to the tree, and it might be among the mechanisms that allow hunter–gatherers to access the canopy safely. Given that we did not find a skeletal correlate for this observed behavior, our results imply that derived aspects of the hominin ankle associated with bipedalism remain compatible with vertical climbing and arboreal resource acquisition. Our findings challenge the persistent arboreal–terrestrial dichotomy that has informed behavioral reconstructions of fossil hominins and highlight the value of using modern humans as models for inferring the limits of hominin arboreality. PMID:23277565

  2. Effect of Antioxidants on DC Tree and Grounded DC Tree in XLPE

    NASA Astrophysics Data System (ADS)

    Kawanami, Hiroshi; Komatsu, Isao; Sekii, Yasuo; Saito, Mitsugu; Sugi, Kazuyuki

    To study the effects of antioxidants on the initiation of the DC tree and the grounded DC tree, experiments were conducted using XLPE specimens containing phenolic and sulfur type antioxidants. Experimental results showed that sulfur type antioxidants in XLPE have the effect of increasing inception voltages of both the DC tree and the grounded DC tree. Based on results of those experiments, the mechanism of increase in the inception voltage of the DC tree and the grounded DC tree by antioxidants was examined along with the mechanism of polarity effects on those trees. Results showed a promotional effect of charge injection from a needle electrode by antioxidants, which are responsible for the increased inception voltages of the DC tree. Charge trapping by antioxidants explains the increase of inception voltages of the grounded DC tree.

  3. MixtureTree annotator: a program for automatic colorization and visual annotation of MixtureTree.

    PubMed

    Chen, Shu-Chuan; Ogata, Aaron

    2015-01-01

    The MixtureTree Annotator, written in JAVA, allows the user to automatically color any phylogenetic tree in Newick format generated from any phylogeny reconstruction program and output the Nexus file. By providing the ability to automatically color the tree by sequence name, the MixtureTree Annotator provides a unique advantage over any other programs which perform a similar function. In addition, the MixtureTree Annotator is the only package that can efficiently annotate the output produced by MixtureTree with mutation information and coalescent time information. In order to visualize the resulting output file, a modified version of FigTree is used. Certain popular methods, which lack good built-in visualization tools, for example, MEGA, Mesquite, PHY-FI, TreeView, treeGraph and Geneious, may give results with human errors due to either manually adding colors to each node or with other limitations, for example only using color based on a number, such as branch length, or by taxonomy. In addition to allowing the user to automatically color any given Newick tree by sequence name, the MixtureTree Annotator is the only method that allows the user to automatically annotate the resulting tree created by the MixtureTree program. The MixtureTree Annotator is fast and easy-to-use, while still allowing the user full control over the coloring and annotating process.

  4. Liana competition with tropical trees varies seasonally but not with tree species identity.

    PubMed

    Leonor, Alvarez-Cansino; Schnitzer, Stefan A; Reid, Joseph P; Powers, Jennifer S

    2015-01-01

    Lianas in tropical forests compete intensely with trees for above- and belowground resources and limit tree growth and regeneration. Liana competition with adult canopy trees may be particularly strong, and, if lianas compete more intensely with some tree species than others, they may influence tree species composition. We performed the first systematic, large-scale liana removal experiment to assess the competitive effects of lianas on multiple tropical tree species by measuring sap velocity and growth in a lowland tropical forest in Panama. Tree sap velocity increased 60% soon after liana removal compared to control trees, and tree diameter growth increased 25% after one year. Although tree species varied in their response to lianas, this variation was not significant, suggesting that lianas competed similarly with all tree species examined. The effect of lianas on tree sap velocity was particularly strong during the dry season, when soil moisture was low, suggesting that lianas compete intensely with trees for water. Under the predicted global change scenario of increased temperature and drought intensity, competition from lianas may become more prevalent in seasonal tropical forests, which, according to our data, should have a negative effect on most tropical tree species.

  5. Assessment of student conceptions of evolutionary trees

    NASA Astrophysics Data System (ADS)

    Blacquiere, Luke

    Biologists use evolutionary trees to depict hypotheses about the relationships among taxa. Trees possess lines that represent lineages, internal nodes that represent where lineages become evolutionarily isolated from one another and terminal nodes that represent the taxa under consideration. Interpreting a tree (i.e., "tree-thinking") is an important skill for biologists yet many students struggle when reading evolutionary trees. Common documented misconceptions include using morphological similarity, internal node counting or terminal node proximity, instead of identifying the internal node that represents a most recent common ancestor (MRCA), to determine relationships among taxa. I developed an instrument to assess whether students were using common ancestry or another, non-scientific, strategy to determine relationships among taxa. The study is the first to explicitly test hypotheses about how students approach reading evolutionary trees. To test the hypotheses an instrument was developed. The instrument is the first reliable and valid assessment testing student understanding of how to use most recent common ancestor to interpret evolutionary relationships in tree diagrams. Instructors can use the instrument as a diagnostic tool enabling them to help students learn this challenging concept. This study shows that, contrary to the assertion that students hold misconceptions about evolutionary trees made in the literature, students do not consistently use erroneous strategies when interpreting trees. This study suggests that a constructivist perspective of cognitive structure describes students' conception of evolutionary trees more closely than a misconception perspective.

  6. Mechanical stability of trees under dynamic loads.

    PubMed

    James, Kenneth R; Haritos, Nicholas; Ades, Peter K

    2006-10-01

    Tree stability in windstorms and tree failure are important issues in urban areas where there can be risks of damage to people and property and in forests where wind damage causes economic loss. Current methods of managing trees, including pruning and assessment of mechanical strength, are mainly based on visual assessment or the experience of people such as trained arborists. Only limited data are available to assess tree strength and stability in winds, and most recent methods have used a static approach to estimate loads. Recent research on the measurement of dynamic wind loads and the effect on tree stability is giving a better understanding of how different trees cope with winds. Dynamic loads have been measured on trees with different canopy shapes and branch structures including a palm (Washingtonia robusta), a slender Italian cypress (Cupressus sempervirens) and trees with many branches and broad canopies including hoop pine (Araucaria cunninghamii) and two species of eucalypt (Eucalyptus grandis, E. teretecornus). Results indicate that sway is not a harmonic, but is very complex due to the dynamic interaction of branches. A new dynamic model of a tree is described, incorporating the dynamic structural properties of the trunk and branches. The branch mass contributes a dynamic damping, termed mass damping, which acts to reduce dangerous harmonic sway motion of the trunk and so minimizes loads and increases the mechanical stability of the tree. The results from 12 months of monitoring sway motion and wind loading forces are presented and discussed.

  7. Self-Organizing Tree Using Cluster Validity

    NASA Astrophysics Data System (ADS)

    Sasaki, Yasue; Suzuki, Yukinori; Miyamoto, Takayuki; Maeda, Junji

    Self-organizing tree (S-TREE) models solve clustering problems by imposing tree-structured constraints on the solution. It has a self-organizing capacity and has better performance than previous tree-structured algorithms. S-TREE carries out pruning to reduce the effect of bad leaf nodes when the tree reaches a predetermined maximum size (U), However, it is difficult to determine U beforehand because it is problem-dependent. U gives the limit of tree growth and can also prevent self-organization of the tree. It may produce an unnatural clustering. In this paper, we propose an algorithm for pruning algorithm that does not require U. This algorithm prunes extra nodes based on a significant level of cluster validity and allows the S-TREE to grow by a self-organization. The performance of the new algorithm was examined by experiments on vector quantization. The results of experiments show that natural leaf nodes are formed by this algorithm without setting the limit for the growth of the S-TREE.

  8. Functional Data Analysis of Tree Data Objects.

    PubMed

    Shen, Dan; Shen, Haipeng; Bhamidi, Shankar; Maldonado, Yolanda Muñoz; Kim, Yongdai; Marron, J S

    2014-01-01

    Data analysis on non-Euclidean spaces, such as tree spaces, can be challenging. The main contribution of this paper is establishment of a connection between tree data spaces and the well developed area of Functional Data Analysis (FDA), where the data objects are curves. This connection comes through two tree representation approaches, the Dyck path representation and the branch length representation. These representations of trees in Euclidean spaces enable us to exploit the power of FDA to explore statistical properties of tree data objects. A major challenge in the analysis is the sparsity of tree branches in a sample of trees. We overcome this issue by using a tree pruning technique that focuses the analysis on important underlying population structures. This method parallels scale-space analysis in the sense that it reveals statistical properties of tree structured data over a range of scales. The effectiveness of these new approaches is demonstrated by some novel results obtained in the analysis of brain artery trees. The scale space analysis reveals a deeper relationship between structure and age. These methods are the first to find a statistically significant gender difference.

  9. The dynamics of strangling among forest trees.

    PubMed

    Okamoto, Kenichi W

    2015-11-07

    Strangler trees germinate and grow on other trees, eventually enveloping and potentially even girdling their hosts. This allows them to mitigate fitness costs otherwise incurred by germinating and competing with other trees on the forest floor, as well as minimize risks associated with host tree-fall. If stranglers can themselves host other strangler trees, they may not even seem to need non-stranglers to persist. Yet despite their high fitness potential, strangler trees neither dominate the communities in which they occur nor is the strategy particularly common outside of figs (genus Ficus). Here we analyze how dynamic interactions between strangling and non-strangling trees can shape the adaptive landscape for strangling mutants and mutant trees that have lost the ability to strangle. We find a threshold which strangler germination rates must exceed for selection to favor the evolution of strangling, regardless of how effectively hemiepiphytic stranglers may subsequently replace their hosts. This condition describes the magnitude of the phenotypic displacement in the ability to germinate on other trees necessary for invasion by a mutant tree that could potentially strangle its host following establishment as an epiphyte. We show how the relative abilities of strangling and non-strangling trees to occupy empty sites can govern whether strangling is an evolutionarily stable strategy, and obtain the conditions for strangler coexistence with non-stranglers. We then elucidate when the evolution of strangling can disrupt stable coexistence between commensal epiphytic ancestors and their non-strangling host trees. This allows us to highlight parallels between the invasion fitness of strangler trees arising from commensalist ancestors, and cases where strangling can arise in concert with the evolution of hemiepiphytism among free-standing ancestors. Finally, we discuss how our results can inform the evolutionary ecology of antagonistic interactions more generally.

  10. Tree canopy radiance measurement system

    NASA Technical Reports Server (NTRS)

    Caldwell, William; Vanderbilt, V. C.

    1989-01-01

    A system is described for obtaining both an estimate of the spatial mean bidirectional reflectance factor (BRF) for a tree canopy (displaying a horizontally heterogeneous foliage distribution) and the statistical significance of that estimate. The system includes a manlift supporting a horizontal beam 7 m long on which are mounted four radiometers. These radiometers may be pointed, and radiance data acquired, in any of 11 view directions in the principal plane of the sun. A total of 80 data points, acquired in 3 min, were used to estimate the BRF of a walnut orchard 5 m tall and detect true differences of 12 percent of the mean approximately 90 percent of the time.

  11. Tree canopy radiance measurement system

    NASA Technical Reports Server (NTRS)

    Caldwell, William; Vanderbilt, V. C.

    1989-01-01

    A system is described for obtaining both an estimate of the spatial mean bidirectional reflectance factor (BRF) for a tree canopy (displaying a horizontally heterogeneous foliage distribution) and the statistical significance of that estimate. The system includes a manlift supporting a horizontal beam 7 m long on which are mounted four radiometers. These radiometers may be pointed, and radiance data acquired, in any of 11 view directions in the principal plane of the sun. A total of 80 data points, acquired in 3 min, were used to estimate the BRF of a walnut orchard 5 m tall and detect true differences of 12 percent of the mean approximately 90 percent of the time.

  12. Tree canopy radiance measurement system

    NASA Astrophysics Data System (ADS)

    Caldwell, William; Vanderbilt, V. C.

    1989-11-01

    A system is described for obtaining both an estimate of the spatial mean bidirectional reflectance factor (BRF) for a tree canopy (displaying a horizontally heterogeneous foliage distribution) and the statistical significance of that estimate. The system includes a manlift supporting a horizontal beam 7 m long on which are mounted four radiometers. These radiometers may be pointed, and radiance data acquired, in any of 11 view directions in the principal plane of the sun. A total of 80 data points, acquired in 3 min, were used to estimate the BRF of a walnut orchard 5 m tall and detect true differences of 12 percent of the mean approximately 90 percent of the time.

  13. Hierarchical clustering in minimum spanning trees

    NASA Astrophysics Data System (ADS)

    Yu, Meichen; Hillebrand, Arjan; Tewarie, Prejaas; Meier, Jil; van Dijk, Bob; Van Mieghem, Piet; Stam, Cornelis Jan

    2015-02-01

    The identification of clusters or communities in complex networks is a reappearing problem. The minimum spanning tree (MST), the tree connecting all nodes with minimum total weight, is regarded as an important transport backbone of the original weighted graph. We hypothesize that the clustering of the MST reveals insight in the hierarchical structure of weighted graphs. However, existing theories and algorithms have difficulties to define and identify clusters in trees. Here, we first define clustering in trees and then propose a tree agglomerative hierarchical clustering (TAHC) method for the detection of clusters in MSTs. We then demonstrate that the TAHC method can detect clusters in artificial trees, and also in MSTs of weighted social networks, for which the clusters are in agreement with the previously reported clusters of the original weighted networks. Our results therefore not only indicate that clusters can be found in MSTs, but also that the MSTs contain information about the underlying clusters of the original weighted network.

  14. Phytoremediation of trichloroethene (TCE) using cottonwood trees

    USGS Publications Warehouse

    Jones, S.A.; Lee, R.W.; Kuniansky, E.L.; ,

    1999-01-01

    The ability of cottonwood trees for phytoremediation was studied on aerobic shallow groundwater containing TCE. Cottonwood trees were planted over a 0.2-ha area at the Naval Air Station at Fort Worth, TX, in April 1996. Two years later, groundwater chemistry in the terrace alluvial aquifer was changing locally. Dissolved oxygen (DO) concentrations declined at the southern end of the whip plantings while total iron concentration increased. Groundwater chemistry near a mature cottonwood tree ~ 60 m from the caliper trees was different from that observed elsewhere. Anaerobic conditions near the mature cottonwood tree were evident. Reductive dechlorination of TCE occurred in the aquifer near the mature tree, as demonstrated by very small concentration of TCE in groundwater, a small median ratio of TCE to the degradation product cis-1,2-DCE and the presence of vinyl chloride.

  15. A balanced neural tree for pattern classification.

    PubMed

    Micheloni, Christian; Rani, Asha; Kumar, Sanjeev; Foresti, Gian Luca

    2012-03-01

    This paper proposes a new neural tree (NT) architecture, balanced neural tree (BNT), to reduce tree size and improve classification with respect to classical NTs. To achieve this result, two main innovations have been introduced: (a) perceptron substitution and (b) pattern removal. The first innovation aims to balance the structure of the tree. If the last-trained perceptron largely misclassifies the given training set into a reduced number of classes, then this perceptron is substituted with a new perceptron. The second novelty consists of the introduction of a new criterion for the removal of tough training patterns that generate the problem of over-fitting. Finally, a new error function based on the depth of the tree is introduced to reduce perceptron training time. The proposed BNT has been tested on various synthetic and real datasets. The experimental results show that the proposed BNT leads to satisfactory results in terms of both tree depth reduction and classification accuracy.

  16. Morphology of branching trees related to entropy.

    PubMed

    Horsfield, K

    1977-04-01

    Analyses of river systems by geomorphologists have suggested that for minimal entropy production in the movement of water down the river the fall in altitude should be equal in each order of branching of the tributaries. In this paper the same concepts have been applied to the bronchial tree and pulmonary arterial tree, assuming that the energy associated with pressure difference is analogous to that associated with altitude difference in rivers. The morphology of the bronchial tree is such that, given laminar flow or air, the calculated pressure difference across each order is equal. This may indicate that the bronchial tree is designed for minimal entropy production. In the arterial tree, however, this result is not obtained, probably because we do not know how to calculate the pressure drop in blood flowing through a branching system. It is therefore not currently possible, on the basis of this approach, to say whether the pulmonary arterial tree is designed for minimal entropy production or not.

  17. Dead Trees Bring Life to Forest Critters

    Treesearch

    Thomas Nicholls; Mike Ostry

    2003-01-01

    What good is a dying or dead tree in a forest? Dead and dying trees don't awe us with their beauty; they just stand or lie there on the forest floor, offering no promise of lumber or other wood products we need. But if we look more closely at such trees, we may see lots of life in them: a raccoon family huddled in a burrow, a downy woodpecker excavating another...

  18. Southern Pine Beetle Population Dynamics in Trees

    Treesearch

    Fred M. Stephen

    2011-01-01

    Successful mass attack of a pine tree by the southern pine beetle (SPB) results in the tree’s death and provides opportunity for colonization of the new phloem resource and reproduction by a new generation of SPBs plus hundreds of associated species of insects, mites, fungi, and nematodes. The within-tree portions of the SPB life history can be divided into component...

  19. Controlling cull ohia trees by injecting herbicides

    Treesearch

    Stanley B. Carpenter

    1966-01-01

    Ohia trees less than 6 inches d .b.h. on the island of Hawaii were killed by injection of undiluted 2,4.S-T ester. This chemical was less effective on larger trees. Injections applied in September and January were more effective than the May applications. Injections of 2,4-D were relatively ineffective, any season of the year, even for small trees. Tardon 22K proved...

  20. Tutorial: Advanced fault tree applications using HARP

    NASA Technical Reports Server (NTRS)

    Dugan, Joanne Bechta; Bavuso, Salvatore J.; Boyd, Mark A.

    1993-01-01

    Reliability analysis of fault tolerant computer systems for critical applications is complicated by several factors. These modeling difficulties are discussed and dynamic fault tree modeling techniques for handling them are described and demonstrated. Several advanced fault tolerant computer systems are described, and fault tree models for their analysis are presented. HARP (Hybrid Automated Reliability Predictor) is a software package developed at Duke University and NASA Langley Research Center that is capable of solving the fault tree models presented.

  1. 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...

  2. Wisconsin street tree assessment, 2002-2003

    Treesearch

    Anne Buckelew Cumming; Daniel B. Twardus; Robert Hoehn; David J. Nowak; Manfred Mielke; Richard Rideout; Helen Butalla; Patricia Lebow

    2008-01-01

    A pilot study to assess the structure, function, and health of Wisconsin’s street trees was initiated in 2002. Almost 900 plots were established in Wisconsin’s urban areas. Table 1 provides an overview of plot-level data, population estimates, and a calculated monetary value for Wisconsin’s street trees. Wisconsin has mid-sized street trees, dominated by Norway maple (...

  3. Creating ensembles of decision trees through sampling

    DOEpatents

    Kamath, Chandrika; Cantu-Paz, Erick

    2005-08-30

    A system for decision tree ensembles that includes a module to read the data, a module to sort the data, a module to evaluate a potential split of the data according to some criterion using a random sample of the data, a module to split the data, and a module to combine multiple decision trees in ensembles. The decision tree method is based on statistical sampling techniques and includes the steps of reading the data; sorting the data; evaluating a potential split according to some criterion using a random sample of the data, splitting the data, and combining multiple decision trees in ensembles.

  4. Fruit load governs transpiration of olive trees

    PubMed Central

    Bustan, Amnon; Dag, Arnon; Yermiyahu, Uri; Erel, Ran; Presnov, Eugene; Agam, Nurit; Kool, Dilia; Iwema, Joost; Zipori, Isaac; Ben-Gal, Alon

    2016-01-01

    We tested the hypothesis that whole-tree water consumption of olives (Olea europaea L.) is fruit load-dependent and investigated the driving physiological mechanisms. Fruit load was manipulated in mature olives grown in weighing-drainage lysimeters. Fruit was thinned or entirely removed from trees at three separate stages of growth: early, mid and late in the season. Tree-scale transpiration, calculated from lysimeter water balance, was found to be a function of fruit load, canopy size and weather conditions. Fruit removal caused an immediate decline in water consumption, measured as whole-plant transpiration normalized to tree size, which persisted until the end of the season. The later the execution of fruit removal, the greater was the response. The amount of water transpired by a fruit-loaded tree was found to be roughly 30% greater than that of an equivalent low- or nonyielding tree. The tree-scale response to fruit was reflected in stem water potential but was not mirrored in leaf-scale physiological measurements of stomatal conductance or photosynthesis. Trees with low or no fruit load had higher vegetative growth rates. However, no significant difference was observed in the overall aboveground dry biomass among groups, when fruit was included. This case, where carbon sources and sinks were both not limiting, suggests that the role of fruit on water consumption involves signaling and alterations in hydraulic properties of vascular tissues and tree organs. PMID:26802540

  5. Belowground carbon trade among tall forest trees

    NASA Astrophysics Data System (ADS)

    Klein, Tamir; Siegwolf, Rolf; Koerner, Christian

    2016-04-01

    Just imagine one tree could hand over large quantities of carbon to another tree. How would that change our thinking about carbon relations of forests, the single biggest biological C reservoir on earth? If such a tree-to-tree C shuttle would exist, it required a demand-supply gradient and a pipeline. Here we show that exactly this unthinkable does occur in overlapping root spheres of tall trees in a mixed temperate forest. Using canopy scale stable carbon isotope labelling applied from a construction crane, we demonstrate that carbon assimilated by spruce is traded over to neighbouring beech, larch, and pine in amounts so large that fine roots almost equilibrate the carbon source signature. The isotope mixing ratio indicated that the interspecific transfer accounted for 40% of the fine root carbon, which is ca. 280 kg ha-1 a-1. This is the first forest scale evidence of a large flux of carbon among mature trees from evolutionary distant taxa. Carbon transfer most likely occurred through common ectomycorrhiza networks, which also exhibited the labelled carbon signal. These observations indicate that while competition for resources (e.g. light, water, nutrients) is often considered the dominant tree-tree interaction in a forest, trees actually interact in more complex pathways including a massive carbon exchange.

  6. Multispectral sensing of citrus young tree decline

    NASA Technical Reports Server (NTRS)

    Edwards, G. J.; Ducharme, E. P.; Schehl, T.

    1975-01-01

    Computer processing of MSS data to identify and map citrus trees affected by young tree decline is analyzed. The data were obtained at 1500-feet altitude in six discrete spectral bands covering regions from 0.53 to 1.3 millimicrons as well as from instrumental ground truths of tree crowns. Measurable spectral reflectance intensity differences are observed in the leaves of healthy and diseased trees, especially at wavelengths of 500 to 600 nm and 700 to 800 nm. The overall accuracy of the method is found to be 89%.

  7. Why are so many trees hollow?

    PubMed Central

    Ruxton, Graeme D.

    2014-01-01

    In many living trees, much of the interior of the trunk can be rotten or even hollowed out. Previously, this has been suggested to be adaptive, with microbial or animal consumption of interior wood producing a rain of nutrients to the soil beneath the tree that allows recycling of those nutrients into new growth via the trees roots. Here I propose an alternative (non-exclusive) explanation: such loss of wood comes at very little cost to the tree and so investment in costly chemical defence of this wood is not economic. I discuss how this theory can be tested empirically. PMID:25392312

  8. Fruit load governs transpiration of olive trees.

    PubMed

    Bustan, Amnon; Dag, Arnon; Yermiyahu, Uri; Erel, Ran; Presnov, Eugene; Agam, Nurit; Kool, Dilia; Iwema, Joost; Zipori, Isaac; Ben-Gal, Alon

    2016-03-01

    We tested the hypothesis that whole-tree water consumption of olives (Olea europaea L.) is fruit load-dependent and investigated the driving physiological mechanisms. Fruit load was manipulated in mature olives grown in weighing-drainage lysimeters. Fruit was thinned or entirely removed from trees at three separate stages of growth: early, mid and late in the season. Tree-scale transpiration, calculated from lysimeter water balance, was found to be a function of fruit load, canopy size and weather conditions. Fruit removal caused an immediate decline in water consumption, measured as whole-plant transpiration normalized to tree size, which persisted until the end of the season. The later the execution of fruit removal, the greater was the response. The amount of water transpired by a fruit-loaded tree was found to be roughly 30% greater than that of an equivalent low- or nonyielding tree. The tree-scale response to fruit was reflected in stem water potential but was not mirrored in leaf-scale physiological measurements of stomatal conductance or photosynthesis. Trees with low or no fruit load had higher vegetative growth rates. However, no significant difference was observed in the overall aboveground dry biomass among groups, when fruit was included. This case, where carbon sources and sinks were both not limiting, suggests that the role of fruit on water consumption involves signaling and alterations in hydraulic properties of vascular tissues and tree organs.

  9. Combinatorics of distance-based tree inference

    PubMed Central

    Pardi, Fabio; Gascuel, Olivier

    2012-01-01

    Several popular methods for phylogenetic inference (or hierarchical clustering) are based on a matrix of pairwise distances between taxa (or any kind of objects): The objective is to construct a tree with branch lengths so that the distances between the leaves in that tree are as close as possible to the input distances. If we hold the structure (topology) of the tree fixed, in some relevant cases (e.g., ordinary least squares) the optimal values for the branch lengths can be expressed using simple combinatorial formulae. Here we define a general form for these formulae and show that they all have two desirable properties: First, the common tree reconstruction approaches (least squares, minimum evolution), when used in combination with these formulae, are guaranteed to infer the correct tree when given enough data (consistency); second, the branch lengths of all the simple (nearest neighbor interchange) rearrangements of a tree can be calculated, optimally, in quadratic time in the size of the tree, thus allowing the efficient application of hill climbing heuristics. The study presented here is a continuation of that by Mihaescu and Pachter on branch length estimation [Mihaescu R, Pachter L (2008) Proc Natl Acad Sci USA 105:13206–13211]. The focus here is on the inference of the tree itself and on providing a basis for novel algorithms to reconstruct trees from distances. PMID:23012403

  10. Combinatorics of distance-based tree inference.

    PubMed

    Pardi, Fabio; Gascuel, Olivier

    2012-10-09

    Several popular methods for phylogenetic inference (or hierarchical clustering) are based on a matrix of pairwise distances between taxa (or any kind of objects): The objective is to construct a tree with branch lengths so that the distances between the leaves in that tree are as close as possible to the input distances. If we hold the structure (topology) of the tree fixed, in some relevant cases (e.g., ordinary least squares) the optimal values for the branch lengths can be expressed using simple combinatorial formulae. Here we define a general form for these formulae and show that they all have two desirable properties: First, the common tree reconstruction approaches (least squares, minimum evolution), when used in combination with these formulae, are guaranteed to infer the correct tree when given enough data (consistency); second, the branch lengths of all the simple (nearest neighbor interchange) rearrangements of a tree can be calculated, optimally, in quadratic time in the size of the tree, thus allowing the efficient application of hill climbing heuristics. The study presented here is a continuation of that by Mihaescu and Pachter on branch length estimation [Mihaescu R, Pachter L (2008) Proc Natl Acad Sci USA 105:13206-13211]. The focus here is on the inference of the tree itself and on providing a basis for novel algorithms to reconstruct trees from distances.

  11. Marginally compact fractal trees with semiflexibility

    NASA Astrophysics Data System (ADS)

    Dolgushev, Maxim; Hauber, Adrian L.; Pelagejcev, Philipp; Wittmer, Joachim P.

    2017-07-01

    We study marginally compact macromolecular trees that are created by means of two different fractal generators. In doing so, we assume Gaussian statistics for the vectors connecting nodes of the trees. Moreover, we introduce bond-bond correlations that make the trees locally semiflexible. The symmetry of the structures allows an iterative construction of full sets of eigenmodes (notwithstanding the additional interactions that are present due to semiflexibility constraints), enabling us to get physical insights about the trees' behavior and to consider larger structures. Due to the local stiffness, the self-contact density gets drastically reduced.

  12. On the Number of Ranked Species Trees Producing Anomalous Ranked Gene Trees.

    PubMed

    Disanto, Filippo; Rosenberg, Noah A

    2014-01-01

    Analysis of probability distributions conditional on species trees has demonstrated the existence of anomalous ranked gene trees (ARGTs), ranked gene trees that are more probable than the ranked gene tree that accords with the ranked species tree. Here, to improve the characterization of ARGTs, we study enumerative and probabilistic properties of two classes of ranked labeled species trees, focusing on the presence or avoidance of certain subtree patterns associated with the production of ARGTs. We provide exact enumerations and asymptotic estimates for cardinalities of these sets of trees, showing that as the number of species increases without bound, the fraction of all ranked labeled species trees that are ARGT-producing approaches 1. This result extends beyond earlier existence results to provide a probabilistic claim about the frequency of ARGTs.

  13. Sulfur nutrition of deciduous trees

    NASA Astrophysics Data System (ADS)

    Herschbach, Cornelia; Rennenberg, Heinz

    2001-01-01

    Sulfur in its reduced form (-II) is an essential nutrient for growth and development, but is mainly available to plants in its oxidised form as sulfate. Deciduous trees take up sulfate by the roots from the soil solution and reduce sulfate to sulfide via assimilatory sulfate reduction in both roots and leaves. For reduction in the leaves, sulfate is loaded into the xylem and transported to the shoot. The surplus of sulfate not reduced in the chloroplast or stored in the vacuole and the surplus of reduced S not used for protein synthesis in the leaves is loaded into the phloem and transported back to the roots. Along the transport path, sulfate and glutathione (GSH) is unloaded from the phloem for storage in xylem and phloem parenchyma as well as in pit and ray cells. Re-mobilised S from storage tissues is loaded into the xylem during spring, but a phloem to xylem exchange does not appear to exist later in the season. As a consequence, a cycling pool of S was only found during the change of the seasons. The sulfate:glutathione ratio in the phloem seems to be involved in the regulation of S nutrition. This picture of S nutrition is discussed in relation to the different growth patterns of deciduous trees from the temperate climate zone, i.e. (1) terminated, (2) periodic and (3) indeterminate growth patterns, and in relation to environmental changes.

  14. Understory plant communities and the functional distinction between savanna trees, forest trees, and pines.

    PubMed

    Veldman, Joseph W; Mattingly, W Brett; Brudvig, Lars A

    2013-02-01

    Although savanna trees and forest trees are thought to represent distinct functional groups with different effects on ecosystem processes, few empirical studies have examined these effects. In particular, it remains unclear if savanna and forest trees differ in their ability to coexist with understory plants, which comprise the majority of plant diversity in most savannas. We used structural equation modeling (SEM) and data from 157 sites across three locations in the southeastern United States to understand the effects of broadleaf savanna trees, broadleaf forest trees, and pine trees on savanna understory plant communities. After accounting for underlying gradients in fire frequency and soil moisture, abundances (i.e., basal area and stem density) of forest trees and pines, but not savanna trees, were negatively correlated with the cover and density (i.e., local-scale species richness) of C4 graminoid species, a defining savanna understory functional group that is linked to ecosystem flammability. In analyses of the full understory community, abundances of trees from all functional groups were negatively correlated with species density and cover. For both the C4 and full communities, fire frequency promoted understory plants directly, and indirectly by limiting forest tree abundance. There was little indirect influence of fire on the understory mediated through savanna trees and pines, which are morefire tolerant than forest trees. We conclude that tree functional identity is an important factor that influences overstory tree relationships with savanna understory plant communities. In particular, distinct relationships between trees and C4 graminoids have implications for grass-tree coexistence and vegetation-fire feedbacks that maintain savanna environments and their associated understory plant diversity.

  15. Understory plant communities and the functional distinction between savanna trees, forest trees, and pines

    SciTech Connect

    Veldman, Joseph W.; Mattingly, W. Brett; Brudvig, Lars A.

    2013-02-01

    Although savanna trees and forest trees are thought to represent distinct functional groups with different effects on ecosystem processes, few empirical studies have examined these effects. In particular, it remains unclear if savanna and forest trees differ in their ability to coexist with understory plants, which comprise the majority of plant diversity in most savannas. We used structural equation modeling (SEM) and data from 157 sites across three locations in the southeastern United States to understand the effects of broadleaf savanna trees, broadleaf forest trees, and pine trees on savanna understory plant communities. After accounting for underlying gradients in fire frequency and soil moisture, abundances (i.e., basal area and stem density) of forest trees and pines, but not savanna trees, were negatively correlated with the cover and density (i.e., local-scale species richness) of C4 graminoid species, a defining savanna understory functional group that is linked to ecosystem flammability. In analyses of the full understory community, abundances of trees from all functional groups were negatively correlated with species density and cover. For both the C4 and full communities, fire frequency promoted understory plants directly, and indirectly by limiting forest tree abundance. There was little indirect influence of fire on the understory mediated through savanna trees and pines, which are more fire tolerant than forest trees. We conclude that tree functional identity is an important factor that influences overstory tree relationships with savanna understory plant communities. In particular, distinct relationships between trees and C4 graminoids have implications for grass-tree coexistence and vegetation-fire feedbacks that maintain savanna environments and their associated understory plant diversity.

  16. Linking leaf and tree water use with an individual-tree model.

    PubMed

    Medlyn, Belinda E; Pepper, David A; O'Grady, Anthony P; Keith, Heather

    2007-12-01

    We tested the ability of a model to scale gas exchange from leaf level to whole-tree level by: (1) measuring leaf gas exchange in the canopy of 10 trees in a tall Eucalyptus delegatensis RT Baker forest in NSW, Australia; (2) monitoring sap flow of the same 10 trees during the measurement week; and (3) using an individual-tree-based model (MAESTRA) to link the two sets of measurements. Photosynthesis and stomatal conductance components of the model were parameterized with the leaf gas exchange data, and canopy structure was parameterized with crown heights, dimensions and leaf areas of each of the measurement trees and up to 45 neighboring trees. Transpiration of the measurement trees was predicted by the model and compared with sap flow data. Leaf gas exchange parameters were similar for all 10 trees, with the exception of two smaller trees that had relatively low stomatal conductances. We hypothesize that these trees may have experienced water stress as a result of competition from large neighboring trees. The model performed well, and in most cases, was able to replicate the time course of tree transpiration. Maximum rates of transpiration were higher than measured rates for some trees and lower than measured rates for others, which may have been a result of inaccuracy in estimating tree leaf area. There was a small lag (about 15-30 minutes) between sap flow and modeled transpiration for some trees in the morning, likely associated with use of water stored in stems. The model also captured patterns of variation in sap flow among trees. Overall, the study confirms the ability of models to estimate forest canopy transpiration from leaf-level measurements.

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

    PubMed

    Feragen, Aasa; Owen, Megan; Petersen, Jens; Wille, Mathilde M W; Thomsen, Laura H; Dirksen, Asger; de Bruijne, Marleen

    2013-01-01

    Statistical analysis of anatomical trees is hard to perform due to differences in the topological structure of the trees. In this paper we define statistical properties of leaf-labeled anatomical trees with geometric edge attributes by considering the anatomical trees as points in the geometric space of leaf-labeled trees. This tree-space is a geodesic metric space where any two trees are connected by a unique shortest path, which corresponds to a tree deformation. However, tree-space is not a manifold, and the usual strategy of performing statistical analysis in a tangent space and projecting onto tree-space is not available. Using tree-space and its shortest paths, a variety of statistical properties, such as mean, principal component, hypothesis testing and linear discriminant analysis can be defined. For some of these properties it is still an open problem how to compute them; others (like the mean) can be computed, but efficient alternatives are helpful in speeding up algorithms that use means iteratively, like hypothesis testing. In this paper, we take advantage of a very large dataset (N = 8016) to obtain computable approximations, under the assumption that the data trees parametrize the relevant parts of tree-space well. Using the developed approximate statistics, we illustrate how the structure and geometry of airway trees vary across a population and show that airway trees with Chronic Obstructive Pulmonary Disease come from a different distribution in tree-space than healthy ones. Software is available from http://image.diku.dk/aasa/software.php.

  18. Tree mortality rates and tree population projections in Baltimore, Maryland, USA

    Treesearch

    David J. Nowak; Miki Kuroda; Daniel E. Crane

    2004-01-01

    Based on re-measurements (1999 and 2001) of randomly-distributed permanent plots within the city boundaries of Baltimore, Maryland, trees are estimated to have an annual mortality rate of 6.6% with an overall annual net change in the number of live trees of -4.2%. Tree mortality rates were significantly different based on tree size, condition, species, and Land use....

  19. Surface storage of rainfall in tree crowns: not all trees are equal

    Treesearch

    E. Gregory McPherson; Q. Xiao; Natalie van Doorn; P. Peper; E. Teach

    2017-01-01

    Urban forests can be an effective strategy for managing stormwater. The soil that supports tree growth acts like a reservoir that reduces runoff. The tree crown intercepts rainfall on leaves and stems and its evaporation reduces water reaching the ground below. Until now surface storage capacities have been studied only for forest trees. Based on forest research, green...

  20. 36 CFR 223.4 - Exchange of trees or portions of trees.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Exchange of trees or portions of trees. 223.4 Section 223.4 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER General Provisions § 223.4 Exchange of trees...

  1. Depth of soil water uptake by tropical rainforest trees during dry periods: does tree dimension matter?

    PubMed

    Stahl, Clément; Hérault, Bruno; Rossi, Vivien; Burban, Benoit; Bréchet, Claude; Bonal, Damien

    2013-12-01

    Though the root biomass of tropical rainforest trees is concentrated in the upper soil layers, soil water uptake by deep roots has been shown to contribute to tree transpiration. A precise evaluation of the relationship between tree dimensions and depth of water uptake would be useful in tree-based modelling approaches designed to anticipate the response of tropical rainforest ecosystems to future changes in environmental conditions. We used an innovative dual-isotope labelling approach (deuterium in surface soil and oxygen at 120-cm depth) coupled with a modelling approach to investigate the role of tree dimensions in soil water uptake in a tropical rainforest exposed to seasonal drought. We studied 65 trees of varying diameter and height and with a wide range of predawn leaf water potential (Ψpd) values. We confirmed that about half of the studied trees relied on soil water below 100-cm depth during dry periods. Ψpd was negatively correlated with depth of water extraction and can be taken as a rough proxy of this depth. Some trees showed considerable plasticity in their depth of water uptake, exhibiting an efficient adaptive strategy for water and nutrient resource acquisition. We did not find a strong relationship between tree dimensions and depth of water uptake. While tall trees preferentially extract water from layers below 100-cm depth, shorter trees show broad variations in mean depth of water uptake. This precludes the use of tree dimensions to parameterize functional models.

  2. Remeasuring tree heights on permanent plots using rectangular coordinates and one angle per tree

    Treesearch

    Robert L. Neal

    1973-01-01

    Heights of permanent sample trees with tops visible from any point can be measured from that point with any clinometer, measuring one vertical angle per tree. Two horizontal angles and one additional vertical angle per observation point are necessary to orient the point to the plot. Permanently recorded coordinates and elevations of tree locations are used with the...

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

    ERIC Educational Resources Information Center

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

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

  4. Robustness to divergence time underestimation when inferring species trees from estimated gene trees.

    PubMed

    DeGiorgio, Michael; Degnan, James H

    2014-01-01

    To infer species trees from gene trees estimated from phylogenomic data sets, tractable methods are needed that can handle dozens to hundreds of loci. We examine several computationally efficient approaches-MP-EST, STAR, STEAC, STELLS, and STEM-for inferring species trees from gene trees estimated using maximum likelihood (ML) and Bayesian approaches. Among the methods examined, we found that topology-based methods often performed better using ML gene trees and methods employing coalescent times typically performed better using Bayesian gene trees, with MP-EST, STAR, STEAC, and STELLS outperforming STEM under most conditions. We examine why the STEM tree (also called GLASS or Maximum Tree) is less accurate on estimated gene trees by comparing estimated and true coalescence times, performing species tree inference using simulations, and analyzing a great ape data set keeping track of false positive and false negative rates for inferred clades. We find that although true coalescence times are more ancient than speciation times under the multispecies coalescent model, estimated coalescence times are often more recent than speciation times. This underestimation can lead to increased bias and lack of resolution with increased sampling (either alleles or loci) when gene trees are estimated with ML. The problem appears to be less severe using Bayesian gene-tree estimates.

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

    ERIC Educational Resources Information Center

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

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

  6. How many trees are enough? Tree death and the urban canopy

    Treesearch

    Lara A. Roman

    2014-01-01

    Massive city tree planting campaigns have invigorated the urban forestry movement, and engaged politicians, planners, and the public in urban greening. Million tree initiatives have been launched in Los Angeles, CA; Denver, CO; New York City, NY; Philadelphia, PA, and other cities. Sacramento, CA even has a five million tree program. These...

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

    PubMed Central

    Sayyari, Erfan; Mirarab, Siavash

    2017-01-01

    Phylogenetic trees inferred using commonly-used models of sequence evolution are unrooted, but the root position matters both for interpretation and downstream applications. This issue has been long recognized; however, whether the potential for discordance between the species tree and gene trees impacts methods of rooting a phylogenetic tree has not been extensively studied. In this paper, we introduce a new method of rooting a tree based on its branch length distribution; our method, which minimizes the variance of root to tip distances, is inspired by the traditional midpoint rerooting and is justified when deviations from the strict molecular clock are random. Like midpoint rerooting, the method can be implemented in a linear time algorithm. In extensive simulations that consider discordance between gene trees and the species tree, we show that the new method is more accurate than midpoint rerooting, but its relative accuracy compared to using outgroups to root gene trees depends on the size of the dataset and levels of deviations from the strict clock. We show high levels of error for all methods of rooting estimated gene trees due to factors that include effects of gene tree discordance, deviations from the clock, and gene tree estimation error. Our simulations, however, did not reveal significant differences between two equivalent methods for species tree estimation that use rooted and unrooted input, namely, STAR and NJst. Nevertheless, our results point to limitations of existing scalable rooting methods. PMID:28800608

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

    PubMed

    Mai, Uyen; Sayyari, Erfan; Mirarab, Siavash

    2017-01-01

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

  9. The history of Newton's apple tree

    NASA Astrophysics Data System (ADS)

    Keesing, R. G.

    1998-05-01

    This article contains a brief introduction to Newton's early life to put into context the subsequent events in this narrative. It is followed by a summary of accounts of Newton's famous story of his discovery of universal gravitation which was occasioned by the fall of an apple in the year 1665/6. Evidence of Newton's friendship with a prosperous Yorkshire family who planted an apple tree arbour in the early years of the eighteenth century to celebrate his discovery is presented. A considerable amount of new and unpublished pictorial and documentary material is included relating to a particular apple tree which grew in the garden of Woolsthorpe Manor (Newton's birthplace) and which blew down in a storm before the year 1816. Evidence is then presented which describes how this tree was chosen to be the focus of Newton's account. Details of the propagation of the apple tree growing in the garden at Woolsthorpe in the early part of the last century are then discussed, and the results of a dendrochronological study of two of these trees is presented. It is then pointed out that there is considerable evidence to show that the apple tree presently growing at Woolsthorpe and known as 'Newton's apple tree' is in fact the same specimen which was identified in the middle of the eighteenth century and which may now be 350 years old. In conclusion early results from a radiocarbon dating study being carried out at the University of Oxford on core samples from the Woolsthorpe tree lend support to the contention that the present tree is one and the same as that identified as Newton's apple tree more than 200 years ago. Very recently genetic fingerprinting techniques have been used in an attempt to identify from which sources the various 'Newton apple trees' planted throughout the world originate. The tentative result of this work suggests that there are two separate varieties of apple tree in existence which have been accepted as 'the tree'. One may conclude that at least some of

  10. The universal tree of life: an update

    PubMed Central

    Forterre, Patrick

    2015-01-01

    Biologists used to draw schematic “universal” trees of life as metaphors illustrating the history of life. It is indeed a priori possible to construct an organismal tree connecting the three major domains of ribosome encoding organisms: Archaea, Bacteria and Eukarya, since they originated by cell division from LUCA. Several universal trees based on ribosomal RNA sequence comparisons proposed at the end of the last century are still widely used, although some of their main features have been challenged by subsequent analyses. Several authors have proposed to replace the traditional universal tree with a ring of life, whereas others have proposed more recently to include viruses as new domains. These proposals are misleading, suggesting that endosymbiosis can modify the shape of a tree or that viruses originated from the last universal common ancestor (LUCA). I propose here an updated version of Woese’s universal tree that includes several rootings for each domain and internal branching within domains that are supported by recent phylogenomic analyses of domain specific proteins. The tree is rooted between Bacteria and Arkarya, a new name proposed for the clade grouping Archaea and Eukarya. A consensus version, in which each of the three domains is unrooted, and a version in which eukaryotes emerged within archaea are also presented. This last scenario assumes the transformation of a modern domain into another, a controversial evolutionary pathway. Viruses are not indicated in these trees but are intrinsically present because they infect the tree from its roots to its leaves. Finally, I present a detailed tree of the domain Archaea, proposing the sub-phylum neo-Euryarchaeota for the monophyletic group of euryarchaeota containing DNA gyrase. These trees, that will be easily updated as new data become available, could be useful to discuss controversial scenarios regarding early life evolution. PMID:26257711

  11. Parallel analog neural networks for tree searching

    NASA Astrophysics Data System (ADS)

    Saylor, Janet; Stork, David G.

    1986-08-01

    We have modeled parallel analog neural networks designed such that their evolution toward final states is equivalent to finding optimal (or nearly optimal) paths through decision trees. This work extends that done on the Traveling Salesman Problem (TSP)[1] and sheds light on the conditions under which analog neural networks can and cannot find solutions to discrete optimization problems. Neural networks show considerable specificity in finding optimal solutions for tree searches; in the cases when a final state does represent a syntactically correct path, that path will be the best path 70-90% of the time—even for trees with up to two thousand nodes. However, it appears that except for trivial networks lacking the ability to ``think globally,'' there exists no general network architecture that can strictly insure the convergence a state that represents a single, continuous, unambiguous path. In fact, we find that for roughly 15% of trees with six generations, 40% of trees with eight generations, and 70% of trees with ten generations, networks evolve to ``broken paths,'' i.e., combinations of the beginning of one and the end of another path through a tree. Tree searches illustrate well neural dynamics because tree structures make the effects of competition and positive feedback apparent. We have found that 1) convergence times for networks with up to 2000 neurons are very rapid, depend on the gain of neurons and magnitude of neural connections but not on the number of generations or branching factor of a tree, 2) all neurons along a ``winning'' path turn on exponentially with the same exponent, and 3) the general computational mechanism of these networks appears to be the pruning of a tree from the outer branches inward, as chain reactions of neurons being quenched tend to propagate along possible paths.

  12. The universal tree of life: an update.

    PubMed

    Forterre, Patrick

    2015-01-01

    Biologists used to draw schematic "universal" trees of life as metaphors illustrating the history of life. It is indeed a priori possible to construct an organismal tree connecting the three major domains of ribosome encoding organisms: Archaea, Bacteria and Eukarya, since they originated by cell division from LUCA. Several universal trees based on ribosomal RNA sequence comparisons proposed at the end of the last century are still widely used, although some of their main features have been challenged by subsequent analyses. Several authors have proposed to replace the traditional universal tree with a ring of life, whereas others have proposed more recently to include viruses as new domains. These proposals are misleading, suggesting that endosymbiosis can modify the shape of a tree or that viruses originated from the last universal common ancestor (LUCA). I propose here an updated version of Woese's universal tree that includes several rootings for each domain and internal branching within domains that are supported by recent phylogenomic analyses of domain specific proteins. The tree is rooted between Bacteria and Arkarya, a new name proposed for the clade grouping Archaea and Eukarya. A consensus version, in which each of the three domains is unrooted, and a version in which eukaryotes emerged within archaea are also presented. This last scenario assumes the transformation of a modern domain into another, a controversial evolutionary pathway. Viruses are not indicated in these trees but are intrinsically present because they infect the tree from its roots to its leaves. Finally, I present a detailed tree of the domain Archaea, proposing the sub-phylum neo-Euryarchaeota for the monophyletic group of euryarchaeota containing DNA gyrase. These trees, that will be easily updated as new data become available, could be useful to discuss controversial scenarios regarding early life evolution.

  13. Individual Tree Biomass Models for Plantation Grown American Sycamore

    Treesearch

    Regan B. Willson; Bryce E. Schlaegel; Harvey E. Kennedy

    1982-01-01

    Individual tree volume and green and dry weight equations are derived for American sycamore from a 5-year-old plantation in southeast Arkansas. Two trees have been destructively sampled each year from each of 20 plots. Observations from 168 trees are used to predict tree weight and volume as a function of dbh, total height, age, and initial number of trees. Separate...

  14. Changes in hardwood growing-stock tree grades

    Treesearch

    David L. Sonderman; Everette D. Rast; Everette D. Rast

    1987-01-01

    Describes changes in provisional tree grades for 351 young, mixed upland hardwood trees 6 years after thinning. Treatments of 30,50, and 70 percent stocking plus a crop-tree release were applied. Results indicate that light thinning and crop-tree thinning produced higher qualitjl and better grade trees than heavy thinning.

  15. Modeling Missing Remeasurement Tree Heights in Forest Inventory Data

    Treesearch

    Raymond M. Sheffield; Callie J. Schweitzer

    2005-01-01

    Missing tree heights are often problematic in compiling forest inventory remeasurement data. Heights for cut and mortality trees are usually not available; calculations of removal or mortality volumes must utilize either a modeled height at the time of tree death or the height assigned to the tree at a previous remeasurement. Less often, tree heights are not available...

  16. Modeling missing remeasurement tree heights in forest inventory data

    Treesearch

    Raymond M. Sheffield; Callie J. Schweitzer

    2002-01-01

    Missing tree heights are often problematic in compiling forest inventory renleasureinent data. Heights for cut and niortality trees are usually not available; calculations of removal or mortality volumes must utilize either a modeled height at the time of tree death or the height assigned to the tree at a previous remeasurement. Less often, tree heights are not...

  17. HOW to Recognize and Reduce Tree Hazards in Recreation Sites

    Treesearch

    Kathyn Robbins

    1986-01-01

    An understanding of the many factors affecting tree hazards in recreation sites will help predict which trees are most likely to fail. Hazard tree management deals with probabilities of failure. This guide, written for anyone involved in management or maintenance of public use areas that contain trees, is intended to help minimize the risk associated with hazard trees...

  18. Fast Tree: Computing Large Minimum-Evolution Trees with Profiles instead of a Distance Matrix

    SciTech Connect

    N. Price, Morgan; S. Dehal, Paramvir; P. Arkin, Adam

    2009-07-31

    Gene families are growing rapidly, but standard methods for inferring phylogenies do not scale to alignments with over 10,000 sequences. We present FastTree, a method for constructing large phylogenies and for estimating their reliability. Instead of storing a distance matrix, FastTree stores sequence profiles of internal nodes in the tree. FastTree uses these profiles to implement neighbor-joining and uses heuristics to quickly identify candidate joins. FastTree then uses nearest-neighbor interchanges to reduce the length of the tree. For an alignment with N sequences, L sites, and a different characters, a distance matrix requires O(N^2) space and O(N^2 L) time, but FastTree requires just O( NLa + N sqrt(N) ) memory and O( N sqrt(N) log(N) L a ) time. To estimate the tree's reliability, FastTree uses local bootstrapping, which gives another 100-fold speedup over a distance matrix. For example, FastTree computed a tree and support values for 158,022 distinct 16S ribosomal RNAs in 17 hours and 2.4 gigabytes of memory. Just computing pairwise Jukes-Cantor distances and storing them, without inferring a tree or bootstrapping, would require 17 hours and 50 gigabytes of memory. In simulations, FastTree was slightly more accurate than neighbor joining, BIONJ, or FastME; on genuine alignments, FastTree's topologies had higher likelihoods. FastTree is available at http://microbesonline.org/fasttree.

  19. New method for counting the number of spanning trees in a two-tree network

    NASA Astrophysics Data System (ADS)

    Xiao, Yuzhi; Zhao, Haixing

    2013-10-01

    The number of spanning trees is an important quantity characterizing the reliability of a network. Generally, the number of spanning trees in a network can be obtained by directly calculating a related determinant corresponding to the network. However, for a large network, evaluating the relevant determinant is intractable. In this paper, we investigate the number of spanning trees in two-tree networks. We first give a new algorithm which avoids the laborious computation of the determinant for counting the number of spanning trees. Using the algorithm, we can obtain the number of spanning trees of any two-tree network in linear time. The result shows that the computation complexity is O(n), which is better than that of the matrix tree theorem with O(n2), where n is the number of steps. We then characterize two-tree networks with the maximum and minimum numbers of spanning trees. Denote by P(t) and K(t), respectively, the two-tree networks of t+2 vertices with the maximum and minimum numbers of spanning trees. Denote by PA and EN, respectively, the two-tree network of t+2 vertices generated by preferential attachment and by equiprobability attachment. By algorithmic analysis and through simulations, we conjecture that NST(K(t))≤NST(PA)≤NST(EN)≤NST(P(t)) as t tends to infinity, where NST(G) is the number of spanning trees of G. As an application of the algorithm, we give the formula of the number of spanning trees of a particular small-world network.

  20. Grading sugar pine saw logs in trees.

    Treesearch

    John W. Henley

    1972-01-01

    Small limbs and small overgrown limbs cause problems when grading saw logs in sugar pine trees. Surface characteristics and lumber recovery information for 426 logs from 64 sugar pine trees were examined. Resulting modifications in the grading specification that allow a grader to ignore small limbs and small limb indicators do not appear to decrease the performance of...

  1. How Trees Help the Power Company!

    ERIC Educational Resources Information Center

    King, Rik

    1992-01-01

    Proposes the utilization of graph theory to solve optimization problems. Defines the notion of spanning trees and presents two algorithms to determine optimization of a spanning tree. Discusses an example to connect towns by power transmission lines at minimum cost. (MDH)

  2. The "Ride for Russia" Tree Lichen Survey

    ERIC Educational Resources Information Center

    Young, Simon

    2013-01-01

    The prevalence of nine indicator lichens found on trees in Northern Europe and Western Russia was used for monitoring air quality. The 4200 mile route of the survey went through eight countries. Surveys were carried out in cities, towns, countryside and forests, and along motorways. The author has conducted tree lichen surveys with pupils from…

  3. A Guide to Street Tree Inventory Software

    Treesearch

    Gene A. Olig; Robert W. Miller

    1997-01-01

    The purpose of this publication is to serve as a reference and guide for urban forestry professionals in the selection of a street tree inventory software program. The programs described include only those that are commercially available. The increasing demand for street tree inventory software follows a trend towards a more computerized society and the increasing...

  4. Tools for valuing tree and park services

    Treesearch

    E.G. McPherson

    2010-01-01

    Arborists and urban foresters plan, design, construct, and manage trees and parks in cities throughout the world. These civic improvements create walkable, cool environments, save energy, reduce stormwater runoff, sequester carbon dioxide, and absorb air pollutants. The presence of trees and green spaces in cities is associated with increases in property values,...

  5. Measurement of Tree Growth in Tropical Forests

    Treesearch

    C. B. Briscoe

    1961-01-01

    The title of my paper--Measurement of Tree Growth in Tropical Forests--is somwhat misleading. Because tree and forest growth determination are essentially the same anywhere, most of what I have to say is as applicable in British Columbia, Japan, or New Zealand as it is in Ecuador or the Philipines.

  6. Large trees losing out to drought

    Treesearch

    Michael G. Ryan

    2015-01-01

    Large trees provide many ecological services in forests. They provide seeds for reproduction and food, habitat for plants and animals, and shade for understory vegetation. Older trees and forests store large quantities of carbon, tend to release more water to streams than their more rapidly growing younger counterparts, and provide wood for human use. Mature...

  7. Market-based approaches to tree valuation

    Treesearch

    Geoffrey H. Donovan; David T. Butry

    2008-01-01

    A recent four-part series in Arborist News outlined different appraisal processes used to value urban trees. The final article in the series described the three generally accepted approaches to tree valuation: the sales comparison approach, the cost approach, and the income capitalization approach. The author, D. Logan Nelson, noted that the sales comparison approach...

  8. Testing tree seeds for vigor: a review

    Treesearch

    F.T. Bonner

    1998-01-01

    This review examines the use of vigor tests for tree seeds. It suggests that precise evaluations of these tests and their application with seeds of woody plants is not yet possible. This is due to the wide genetic variation, primarily manifested in variable maturity and dormancy, that exists in most tree seed lots. Sensitive measurements of germination rate during...

  9. 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…

  10. Naturalized Exotic Tree Species in Puerto Rico

    Treesearch

    John K. Francis; Henri A. Liogier

    1991-01-01

    Many exotic tree species have been imported into Puerto Rico for their wood, fruit, and use as coffee shade and ornamentals. Some of these trees have naturalized (reproduced without human intervention) and some have escaped into natural forests. At least 118 exotic species are reproducing in Puerto Rico. Estimates are given for the general rate of spread and future...

  11. Structure, composition, and condition of overstory trees

    Treesearch

    Daniel A. Yaussy; Todd F. Hutchinson; Elaine Kennedy Sutherland

    2003-01-01

    The structure, composition, and condition of overstory trees in the four study areas prior to prescribed fire treatments are summarized. Stand initiation dates were similar among the study areas (ca. 1885), and coincided with the decline of the charcoal iron industry in southern Ohio. Tree basal area averaged 26.8m²/ha and was not significantly different among...

  12. Tree ecophysiology research at Taylor Woods

    Treesearch

    Thomas E. Kolb; Nate G. McDowell

    2008-01-01

    We summarize the key findings of tree ecophysiology studies performed at Taylor Woods, Fort Valley Experimental Forest, Arizona between 1994 and 2003 that provide unique insight on impacts of long-term stand density management in ponderosa pine forests on tree water relations, leaf gas exchange, radial growth, leaf area-to-sapwood-area ratio, growth efficiency, leaf...

  13. Tree value system: description and assumptions.

    Treesearch

    D.G. Briggs

    1989-01-01

    TREEVAL is a microcomputer model that calculates tree or stand values and volumes based on product prices, manufacturing costs, and predicted product recovery. It was designed as an aid in evaluating management regimes. TREEVAL calculates values in either of two ways, one based on optimized tree bucking using dynamic programming and one simulating the results of user-...

  14. Structure of an urban Christmas tree market

    Treesearch

    Thomas H. Pendleton; Lawrence D. Garrett; Lawrence D. Garrett

    1973-01-01

    The retail Christmas tree market in Winston-Salem, N.C., was studied 3 years. Types of retailers and their sales are described. Best sales were made by dealers who had lots on heavily traveled streets in business districts, had ample parking facilities, advertised, and displayed their trees well.

  15. Protection of tree seedlings from deer browsing

    Treesearch

    Jeffrey S. Ward; George R. Stephens

    1995-01-01

    Browsing by large deer herds has seriously impaired successful regeneration on some Connecticut forests. Six plots were established in 1990 to examine the effectiveness of 5 deer browsing protection devices for 5 tree species. Protective devices included plastic mesh sleeves (60-cm), Reemay (spunbonded polypropylene) sleeves (60-cm), Tubex tree shelters (120 and 180-cm...

  16. Newly planted street tree growth and mortality

    Treesearch

    David J. Nowak; Joe R. McBride; Russell A. Beatty

    1990-01-01

    Two-year growth and mortality rates were analyzed for 254 black locust, 199 southern magnolia and 27 London plane trees planted along a major boulevard extending from southern Berkeley through western inner-city Oakland, California. After the first two years, 34% of these newly planted trees were either dead or removed. The average annual mortality rate was 19% with no...

  17. Genetic interactions underlying tree branch orientation

    USDA-ARS?s Scientific Manuscript database

    Expanding our understanding of the molecular and genetic mechanisms behind branch orientation in trees both addresses a fundamental developmental phenomenon and can lead to significant impacts on tree crop agriculture and forestry. Using the p-nome (pooled genome) sequencing-based mapping approac...

  18. Pulp quality from small-diameter trees.

    Treesearch

    G.C. Myers; S. Kumar; R.R. Gustafson; R.J. Barbour; S.M. Abubakr

    1997-01-01

    Kraft and thermomechanical (TMP) pulps were prepared and evaluated from lodgepole pine and mixed Douglas-fir/western larch sawmill residue chips; lodgepole pine, Douglas-fir, and western larch submerchantable logs; and lodgepole pine, Douglas-fir, and western larch small trees and tops. Kraft pulp from small trees and tops was identical to that from submerchantable...

  19. Tree rings and the local environment

    Treesearch

    Kevin T. Smith

    2011-01-01

    The amount of wood produced by a tree each year depends on tree condition, genetic programming, and growing conditions. Wood is mature xylem, the result of inward cell divisions by the vascular cambium, the new cell generator located between the wood and the inner bark (phloem). In temperate climatic zones, where a spring and summer growing season alternates with...

  20. 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…

  1. Initial Field Testing for Forest Tree Improvement

    Treesearch

    C. B. Briscoe

    1963-01-01

    Initial field testing for forest tree improvement is essentially a comparison of genetic groups whether the level of comparison is of species, provenances, or individual trees. A good study design should be as economical as possible, for a given precision, and must be accurate. The latter is simply obtained by restricting the study to a specified set of conditions,...

  2. Tree planting in the United States - 1998

    Treesearch

    R.J. Moulton; G. Hernandez

    2000-01-01

    This annual report summarizes tree planting, timber stand improvement, and nursery production activities across all ownerships of forest land in the United States. It includes State-by-State and ownership breakdowns, regional totals, as well as analysis of trends in the data. It does not include tree planting in urban and community environments. As far as we know, it...

  3. Improved trees: economic promises and pitfalls

    Treesearch

    George F. Dutrow

    1977-01-01

    Surging demands for wood fiber that must be produced on a decreasing acreage of forest land suggest soaring prices, a shrinking market for wood products, or both. Either of these consequences can be forestalled or prevented by implementing existing technologies, one of which is cultivation of genetically improved trees. Multiple and sizable gains from improved trees...

  4. Sussing merger trees: stability and convergence

    NASA Astrophysics Data System (ADS)

    Wang, Yang; Pearce, Frazer R.; Knebe, Alexander; Schneider, Aurel; Srisawat, Chaichalit; Tweed, Dylan; Jung, Intae; Han, Jiaxin; Helly, John; Onions, Julian; Elahi, Pascal J.; Thomas, Peter A.; Behroozi, Peter; Yi, Sukyoung K.; Rodriguez-Gomez, Vicente; Mao, Yao-Yuan; Jing, Yipeng; Lin, Weipeng

    2016-06-01

    Merger trees are routinely used to follow the growth and merging history of dark matter haloes and subhaloes in simulations of cosmic structure formation. Srisawat et al. compared a wide range of merger-tree-building codes. Here we test the influence of output strategies and mass resolution on tree-building. We find that, somewhat surprisingly, building the tree from more snapshots does not generally produce more complete trees; instead, it tends to shorten them. Significant improvements are seen for patching schemes that attempt to bridge over occasional dropouts in the underlying halo catalogues or schemes that combine the halo-finding and tree-building steps seamlessly. The adopted output strategy does not affect the average number of branches (bushiness) of the resultant merger trees. However, mass resolution has an influence on both main branch length and the bushiness. As the resolution increases, a halo with the same mass can be traced back further in time and will encounter more small progenitors during its evolutionary history. Given these results, we recommend that, for simulations intended as precursors for galaxy formation models where of the order of 100 or more snapshots are analysed, the tree-building routine should be integrated with the halo finder, or at the very least be able to patch over multiple adjacent snapshots.

  5. Does turgor limit growth in tall trees?

    Treesearch

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

    2004-01-01

    The gravitational component of water potential contributes a standing 0.01 MPa m1 to the xylem tension gradient in plants. In tall trees, this contribution can significantly reduce the water potential near the tree tops. The turgor of cells in buds and leaves is expected to decrease in direct proportion with leaf water potential along a height gradient unless osmotic...

  6. Trees in the Web of Life

    PubMed Central

    Swithers, Kristen S; Gogarten, J Peter; Fournier, Gregory P

    2009-01-01

    Reconstructing the 'Tree of Life' is complicated by extensive horizontal gene transfer between diverse groups of organisms. While numerous conceptual and technical obstacles remain, a report in this issue of Journal of Biology from Koonin and colleagues on the largest-scale prokaryotic genomic reconstruction yet attempted shows that such a tree is discernible, although its branches cannot be traced. PMID:19664165

  7. How Trees Help the Power Company!

    ERIC Educational Resources Information Center

    King, Rik

    1992-01-01

    Proposes the utilization of graph theory to solve optimization problems. Defines the notion of spanning trees and presents two algorithms to determine optimization of a spanning tree. Discusses an example to connect towns by power transmission lines at minimum cost. (MDH)

  8. The "Ride for Russia" Tree Lichen Survey

    ERIC Educational Resources Information Center

    Young, Simon

    2013-01-01

    The prevalence of nine indicator lichens found on trees in Northern Europe and Western Russia was used for monitoring air quality. The 4200 mile route of the survey went through eight countries. Surveys were carried out in cities, towns, countryside and forests, and along motorways. The author has conducted tree lichen surveys with pupils from…

  9. Trends in shortleaf pine tree improvement

    Treesearch

    Robert N. Kitchens

    1986-01-01

    Tree improvement programs of shortleaf pine (Pinus echinata Mill.) have developed over the past 25 years to the point that virtually all demand for planting stock is met with genetically improved trees. About 22,600 acres of improved stock are planted each year. Although shortleaf has the largest geographic range of any southern pine, it is not being promoted in...

  10. Concurrent Manipulation of Binary Search Trees. Revision.

    DTIC Science & Technology

    1979-09-01

    trees (or often B*-trees; see Wedekind [23]) as the main data structure (e.g., Astrachan, et.aL[1]). These structures have the advantage that they are...Conference Proceedings 46 (1977), 637-644. 23. Wedekind . On the Selection of Access Paths in a Data Base System. In Data Base Management, North-Holland

  11. The production of homozygous tree material

    Treesearch

    Reinhard F. Stettler; George E. Howe

    1966-01-01

    Homozygous trees will never be the desired ultimate step in a forest tree improvement program. However, they will serve many purposes in forest genetics research: (1) in the detection of genetic markers; (2) in the isolation of traits under simple genetic control for the study of growth and differentiation phenomena; (3) as a tool as well as reference material in the...

  12. Exploring connections between trees and human health

    Treesearch

    Geoffrey Donovan; Marie. Oliver

    2014-01-01

    Humans have intuitively understood the value of trees to their physical and mental health since the beginning of recorded time. A scientist with the Pacific Northwest Research Station wondered if such a link could be scientifically validated. His research team took advantage of an infestation of emerald ash borer, an invasive pest that kills ash trees, to conduct a...

  13. Tree chemistry database (version 1.0)

    Treesearch

    Linda H. Pardo; Molly Robin-Abbott; Natasha Duarte; Eric K. Miller

    2005-01-01

    The Tree Chemistry Database is a relational database of C, N, P, K, Ca, Mg, Mn, and Al concentrations in bole bark, bole wood, branches, twigs, and foliage. Compiled from data in 218 articles and publications, the database contains reported nutrient and biomass values for tree species in the Northeastern United States. Nutrient data can be sorted on parameters such as...

  14. Percolation on general trees and HIV modeling

    NASA Astrophysics Data System (ADS)

    Ahmed, E.; Agiza, H. N.

    1996-12-01

    Percolation on a general tree is studied. A general tree is used to model the transition from HIV infection into AIDS and to explain the large differences of the transition time from one patient to another. HIV has some autoimmune effects due to its low antigenic mutants. Fuzzy mathematics is used to explain these effects.

  15. BTREE: A FORTRAN Code for B+ Tree.

    DTIC Science & Technology

    2014-09-26

    such large databases. NSWC TR 85-54 REFERENCES 1. Comer , D., "The Ubiquitous B Tree," Computing Surveys, Vol. 11, 1979, pp. 121-137. 2. Knuth, D...34The Ubiquitous B Tree" by Douglas Comer , Computing Surveys, C 11(1979)121-137; a more complete discussion can be found in C "The Art of Computer

  16. Trees in Art, Literature, and Nature.

    ERIC Educational Resources Information Center

    Herzberg, Catherine Kenton

    1997-01-01

    Outlines a grade 5 unit on trees combining art, science, math. language arts, social studies, history, and technology. Highlights "Sky Tree" written by Candace Christiansen and illustrated by Thomas Locker. Provides an annotated bibliography (K-5) of picture and information books, fiction, and videos, and describes art and content area…

  17. Sprouting of dormant buds on border trees

    Treesearch

    G.R., Jr. Trimble; H. Clay Smith; H. Clay Smith

    1970-01-01

    As part of an evaluation of silvicultura1 systems used in managing Appalachian hardwoods, we are studying degrade of border trees surrounding harvest-cut openings made in the patch cutting and group selection systems. One facet of this research dealt with determining what portion of visually evident dormant buds on border tree boles sprouted when the openings were cut...

  18. Molecular basis of angiosperm tree architecture

    USDA-ARS?s Scientific Manuscript database

    The shoot architecture of trees greatly impacts orchard and forest management methods. Amassing greater knowledge of the molecular genetics behind tree form can benefit these industries as well as contribute to basic knowledge of plant developmental biology. This review covers basic components of ...

  19. Environmental stress and whole-tree physiology

    Treesearch

    Peter L. Jr. Lorio

    1993-01-01

    Interactions among bark beetles, pathogens, and conifers constitute a triangle. Another triangle of interactions exist among the invading organism (bark beetles and pathogens), the trees, and the environment. How important, variable or constant, simple or complex, is the role of trees in these triangles? Understanding the wide range of interactions that take place...

  20. Your Tree's Trouble May Be You

    Treesearch

    USDA Forest Service

    1974-01-01

    People spend much time, effort and money to plant and maintain trees around their homes, businesses, public buildings and parks. People are attracted by the scenic and recreational qualities of forest environments. Yet people who love trees the most may unknowingly cause them injury, directly or indirectly, as a result of: Building and road construction, Flooding ,Soil...

  1. Tree improvement research in oak species

    Treesearch

    Franklin C. Cech

    1971-01-01

    Early efforts at developing new forms of oak by interspecific hybridization have not been very successful, although spontaneous hybrids appear rather readily in nature. Preliminary reports on a few seed-source or provenance studies indicate that differences among sources are generally less than differences among trees within sources. This directs tree-improvement...

  2. Tree Planting - Forests Made by Hand

    Treesearch

    Jim Barnett

    1999-01-01

    The typical tree-planting scene hasn't changed much in 50 years. Workers armed with tree bags on their backs and hoedads or dibbles will line up on a frosy morning to begin the process of putting seedlings in the ground one by one.

  3. 'Christmas tree' created by Skylab 4 crewmembers

    NASA Technical Reports Server (NTRS)

    1973-01-01

    This 'Christmas tree' was created by the three crewmen of the third manned Skylab mission aboard the space station in Earth orbit. Food cans were used to fashion the tree. This photograph was made from a television transmission made from a video tape recording on December 24, 1973.

  4. Detecting tree mass changes using accelerometers

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    During the course of a day, the mass of a tree changes as an effect of water transport within the tree, and intercepted water by the leaves of the tree canopy. Trees transport water through the roots and stem up to the canopy for transpiration. This process slows down when soil moisture in the root zone decreases. An accelerometer was mounted just below the crown of a plane (Platanus x hispanica) tree in Delft, the Netherlands, to measure the displacement and acceleration in three dimensions. Using spectral analysis, a diurnal pattern in the governing frequencies was found. Additional meteorological, sap flow, and canopy interception measurements are used to analyze the signal, and explain the variations in the governing frequencies. The goal of this study is to quantify the mass changes in a tree using 3D acceleration data, and separate this into contributions from interception, and changes in tree water content. This will allow further investigation of detecting and quantifying the effect of water stress on tree dynamics in forest canopies.

  5. The First Darwinian Phylogenetic Tree of Plants.

    PubMed

    Hoßfeld, Uwe; Watts, Elizabeth; Levit, Georgy S

    2017-02-01

    In 1866, the German zoologist Ernst Haeckel (1834-1919) published the first Darwinian trees of life in the history of biology in his book General Morphology of Organisms. We take a specific look at the first phylogenetic trees for the plant kingdom that Haeckel created as part of this two-volume work. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Electrical signals in avocado trees

    PubMed Central

    Oyarce, Patricio

    2010-01-01

    Plant responses to environmental changes are associated with electrical excitability and signaling; automatic and continuous measurements of electrical potential differences (ΔEP) between plant tissues can be effectively used to study information transport mechanisms and physiological responses that result from external stimuli on plants. The generation and conduction of electrochemical impulses within plant different tissues and organs, resulting from abiotic and biotic changes in environmental conditions is reported. In this work, electrical potential differences are monitored continuously using Ag/AgCl microelectrodes, inserted 5 mm deep into sapwood at two positions in the trunks of several Avocado trees. Electrodes are referenced to a non polarisable Ag/AgCl microelectrode installed 20 cm deep in the soil. Systematic patterns of ΔEP during absolute darkness, day-night cycles and different conditions of soil water availability are discussed as alternative tools to assess early plant stress conditions. PMID:20592805

  7. Genealogical Trees of Scientific Papers.

    PubMed

    Waumans, Michaël Charles; Bersini, Hugues

    2016-01-01

    Many results have been obtained when studying scientific papers citations databases in a network perspective. Articles can be ranked according to their current in-degree and their future popularity or citation counts can even be predicted. The dynamical properties of such networks and the observation of the time evolution of their nodes started more recently. This work adopts an evolutionary perspective and proposes an original algorithm for the construction of genealogical trees of scientific papers on the basis of their citation count evolution in time. The fitness of a paper now amounts to its in-degree growing trend and a "dying" paper will suddenly see this trend declining in time. It will give birth and be taken over by some of its most prevalent citing "offspring". Practically, this might be used to trace the successive published milestones of a research field.

  8. Fault trees and imperfect coverage

    NASA Technical Reports Server (NTRS)

    Dugan, Joanne B.

    1989-01-01

    A new algorithm is presented for solving the fault tree. The algorithm includes the dynamic behavior of the fault/error handling model but obviates the need for the Markov chain solution. As the state space is expanded in a breadth-first search (the same is done in the conversion to a Markov chain), the state's contribution to each future state is calculated exactly. A dynamic state truncation technique is also presented; it produces bounds on the unreliability of the system by considering only part of the state space. Since the model is solved as the state space is generated, the process can be stopped as soon as the desired accuracy is reached.

  9. Marginally compact hyperbranched polymer trees.

    PubMed

    Dolgushev, M; Wittmer, J P; Johner, A; Benzerara, O; Meyer, H; Baschnagel, J

    2017-03-29

    Assuming Gaussian chain statistics along the chain contour, we generate by means of a proper fractal generator hyperbranched polymer trees which are marginally compact. Static and dynamical properties, such as the radial intrachain pair density distribution ρpair(r) or the shear-stress relaxation modulus G(t), are investigated theoretically and by means of computer simulations. We emphasize that albeit the self-contact density diverges logarithmically with the total mass N, this effect becomes rapidly irrelevant with increasing spacer length S. In addition to this it is seen that the standard Rouse analysis must necessarily become inappropriate for compact objects for which the relaxation time τp of mode p must scale as τp ∼ (N/p)(5/3) rather than the usual square power law for linear chains.

  10. A-3 First Tree Cutting

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Tree clearing for the site of the new A-3 Test Stand at Stennis Space center began June 13. NASA's first new large rocket engine test stand to be built since the site's inception, A-3 construction begins a historic era for America's largest rocket engine test complex. The 300-foot-tall structure is scheduled for completion in August 2010. A-3 will perform altitude tests on the Constellation's J-2X engine that will power the upper stage of the Ares I crew launch vehicle and earth departure stage of the Ares V cargo launch vehicle. The Constellation Program, NASA's plan for carrying out the nation's Vision for Space Exploration, will return humans to the moon and eventually carry them to Mars and beyond.

  11. A-3 First Tree Cutting

    NASA Image and Video Library

    2007-06-13

    Tree clearing for the site of the new A-3 Test Stand at Stennis Space center began June 13. NASA's first new large rocket engine test stand to be built since the site's inception, A-3 construction begins a historic era for America's largest rocket engine test complex. The 300-foot-tall structure is scheduled for completion in August 2010. A-3 will perform altitude tests on the Constellation's J-2X engine that will power the upper stage of the Ares I crew launch vehicle and earth departure stage of the Ares V cargo launch vehicle. The Constellation Program, NASA's plan for carrying out the nation's Vision for Space Exploration, will return humans to the moon and eventually carry them to Mars and beyond.

  12. Robins gather in a tree

    NASA Technical Reports Server (NTRS)

    2000-01-01

    In a wooded area of Kennedy Space Center, robins gather on a tree branch just beginning to show new Spring growth. A member of the thrush family, robins inhabit towns, gardens, open woodlands and agricultural lands. They range through most of North America, spending winters in large roosts mostly in the United States but also Newfoundland, southern Ontario and British Columbia. The Center shares a boundary with the Merritt Island National Wildlife Refuge, a haven and habitat for more than 331 species of birds. The Refuge encompasses 92,000 acres that are also a habitat for 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects.

  13. Genealogical Trees of Scientific Papers

    PubMed Central

    Waumans, Michaël Charles; Bersini, Hugues

    2016-01-01

    Many results have been obtained when studying scientific papers citations databases in a network perspective. Articles can be ranked according to their current in-degree and their future popularity or citation counts can even be predicted. The dynamical properties of such networks and the observation of the time evolution of their nodes started more recently. This work adopts an evolutionary perspective and proposes an original algorithm for the construction of genealogical trees of scientific papers on the basis of their citation count evolution in time. The fitness of a paper now amounts to its in-degree growing trend and a “dying” paper will suddenly see this trend declining in time. It will give birth and be taken over by some of its most prevalent citing “offspring”. Practically, this might be used to trace the successive published milestones of a research field. PMID:26954677

  14. A-3 First Tree Cutting

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Tree clearing for the site of the new A-3 Test Stand at Stennis Space center began June 13. NASA's first new large rocket engine test stand to be built since the site's inception, A-3 construction begins a historic era for America's largest rocket engine test complex. The 300-foot-tall structure is scheduled for completion in August 2010. A-3 will perform altitude tests on the Constellation's J-2X engine that will power the upper stage of the Ares I crew launch vehicle and earth departure stage of the Ares V cargo launch vehicle. The Constellation Program, NASA's plan for carrying out the nation's Vision for Space Exploration, will return humans to the moon and eventually carry them to Mars and beyond.

  15. Homological Computation Using Spanning Trees

    NASA Astrophysics Data System (ADS)

    Molina-Abril, H.; Real, P.

    We introduce here a new mathbb{F}_2 homology computation algorithm based on a generalization of the spanning tree technique on a finite 3-dimensional cell complex K embedded in ℝ3. We demonstrate that the complexity of this algorithm is linear in the number of cells. In fact, this process computes an algebraic map φ over K, called homology gradient vector field (HGVF), from which it is possible to infer in a straightforward manner homological information like Euler characteristic, relative homology groups, representative cycles for homology generators, topological skeletons, Reeb graphs, cohomology algebra, higher (co)homology operations, etc. This process can be generalized to others coefficients, including the integers, and to higher dimension.

  16. Robins gather in a tree

    NASA Technical Reports Server (NTRS)

    2000-01-01

    In a wooded area of Kennedy Space Center, robins gather on a tree branch just beginning to show new Spring growth. A member of the thrush family, robins inhabit towns, gardens, open woodlands and agricultural lands. They range through most of North America, spending winters in large roosts mostly in the United States but also Newfoundland, southern Ontario and British Columbia. The Center shares a boundary with the Merritt Island National Wildlife Refuge, a haven and habitat for more than 331 species of birds. The Refuge encompasses 92,000 acres that are also a habitat for 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects.

  17. Stand conditions and tree characteristics affect quality of longleaf pine for red-cockaded woodpecker cavity trees

    Treesearch

    W.G. Ross; D.L. Kulhavy; R.N. Conner

    1997-01-01

    We measured resin flow of longleaf (Pinus palustris Mill.) pines in red-cockaded woodpecker (Picoides borealis Vieillot) clusters in the Angelina National Forest in Texas, and the Apalachicola National Forest in Florida. Sample trees were categorized as active cavity trees, inactive cavity trees and control trees. Sample trees were further...

  18. Language distance and tree reconstruction

    NASA Astrophysics Data System (ADS)

    Petroni, Filippo; Serva, Maurizio

    2008-08-01

    Languages evolve over time according to a process in which reproduction, mutation and extinction are all possible. This is very similar to haploid evolution for asexual organisms and for the mitochondrial DNA of complex ones. Exploiting this similarity, it is possible, in principle, to verify hypotheses concerning the relationship among languages and to reconstruct their family tree. The key point is the definition of the distances among pairs of languages in analogy with the genetic distances among pairs of organisms. Distances can be evaluated by comparing grammar and/or vocabulary, but while it is difficult, if not impossible, to quantify grammar distance, it is possible to measure a distance from vocabulary differences. The method used by glottochronology computes distances from the percentage of shared 'cognates', which are words with a common historical origin. The weak point of this method is that subjective judgment plays a significant role. Here we define the distance of two languages by considering a renormalized edit distance among words with the same meaning and averaging over the two hundred words contained in a Swadesh list. In our approach the vocabulary of a language is the analogue of DNA for organisms. The advantage is that we avoid subjectivity and, furthermore, reproducibility of results is guaranteed. We apply our method to the Indo-European and the Austronesian groups, considering, in both cases, fifty different languages. The two trees obtained are, in many respects, similar to those found by glottochronologists, with some important differences as regards the positions of a few languages. In order to support these different results we separately analyze the structure of the distances of these languages with respect to all the others.

  19. Dynamic asset trees and portfolio analysis

    NASA Astrophysics Data System (ADS)

    Onnela, J.-P.; Chakraborti, A.; Kaski, K.; Kertiész, J.

    2002-12-01

    The minimum spanning tree, based on the concept of ultrametricity, is constructed from the correlation matrix of stock returns and provides a meaningful economic taxonomy of the stock market. In order to study the dynamics of this asset tree we characterise it by its normalised length and by the mean occupation layer, as measured from an appropriately chosen centre called the `central node'. We show how the tree evolves over time, and how it shrinks strongly, in particular, during a stock market crisis. We then demonstrate that the assets of the optimal Markowitz portfolio lie practically at all times on the outskirts of the tree. We also show that the normalised tree length and the investment diversification potential are very strongly correlated.

  20. Deepwater satellite trees meet Cormorant challenges

    SciTech Connect

    Hettinger, F.L.; Humphrey, B.

    1984-02-01

    Shell and Esso's Central Cormorant field project is one of the most innovative endeavors in offshore oil field history. Although most of the attention has centered around Shell Expro's Underwater Manifold Center (UMC), the field also will include production from five diverless through flow line (TFL) satellite trees, which were designed, fabricated, and tested by Vetco Offshore. The first satellite tree (P1) was brought on stream in January 1981 and has produced continuously to the South Cormorant platform. The remaining four trees were assembled between 1981 and 1983. These deepwater trees, representing a technically advanced design, will be used to produce from formations at a considerable distance from the UMC. The basic design criteria for the trees include diverless operation, dual hydraulically controlled master valves, 5,000-psi working pressure, chemical injection capability, 200 F produced fluid temperature, H/sub 2/S-CO/sub 2/ service, metal-to-metal seals throughout, and TFL well maintenance and service capability.