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Hunt, Ailsa Gaynor. "Rooted in religion : the Roman sacred tree." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.608102.
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Zhao, Jinhua. "Maximum Bounded Rooted-Tree Problem : Algorithms and Polyhedra." Thesis, Université Clermont Auvergne (2017-2020), 2017. http://www.theses.fr/2017CLFAC044/document.
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Étant donnés un graphe simple non orienté G = (V, E) et un sommet particulier r dans V appelé racine, un arbre enraciné, ou r-arbre, de G est soit le graphe nul soit un arbre contenant r. Si un vecteur de capacités sur les sommets est donné, un sous-graphe de G est dit borné si le degré de chaque sommet dans le sous-graphe est inférieur ou égal à sa capacité. Soit w un vecteur de poids sur les arêtes et p un vecteur de profits sur les sommets. Le problème du r-arbre borné maximum (MBrT, de l’anglais Maximum Bounded r-Tree) consiste à trouver un r-arbre borné T = (U, F) de G tel que son poids soit maximisé. Si la contrainte de capacité du problème MBrT est relâchée, nous obtenons le problème du r-arbre maximum (MrT, de l’anglais Maximum r-Tree). Cette thèse contribue à l’étude des problèmes MBrT et MrT.Tout d’abord, ces deux problèmes sont formellement définis et leur complexité est étudiée. Nous présentons ensuite des polytopes associés ainsi qu’une formulation pour chacun d’entre eux. Par la suite, nous proposons plusieurs algorithmes combinatoires pour résoudre le problème MBrT (et donc le problème MrT) en temps polynomial sur les arbres, les cycles et les cactus. En particulier, un algorithme de programmation dynamique est utilisé pour résoudre le problème MBrT sur les arbres. Pour les cycles, nous sommes amenés a considérer trois cas différents pour lesquels le problem MBrT se réduit à certains problèmes polynomiaux. Pour les cactus, nous montrons tout d’abord que le problème MBrT peut être résolu en temps polynomial sur un type de graphes appelé cactus basis. En utilisant une série de décompositions en sous-problèmes sur les arbres et les cactus basis, nous obtenons un algorithme pour les graphes de type cactus.La deuxième partie de ce travail étudie la structure polyédrale de trois polytopes associés aux problèmes MBrT et MrT. Les deux premiers polytopes, Bxy(G,r,c) et Bx(G,r,c) sont associés au problème MBrT. Tous deux considèrent des variables sur les arêtes de G, mais seuls Bxy(G,r,c) possède également des variables sur les sommets de G. Le troisième polytope, Rx(G,r), est associé au problème MrT et repose uniquement sur les variables sur les arêtes. Pour chacun de ces trois polytopes, nous étudions sa dimension, caractérisons certaines inégalités définissant des facettes, et présentons les moyens possibles de décomposition. Nous introduisons également de nouvelles familles de contraintes. L’ajout de ces contraintes nous permettent de caractériser ces trois polytopes dans plusieurs classes de graphes.Pour finir, nous étudions les problèmes de séparation pour toutes les inégalités que nous avons trouvées jusqu’ici. Des algorithmes polynomiaux de séparation sont présentés, et lorsqu’un problème de séparation est NP-difficile, nous donnons des heuristiques de séparation. Tous les résultats théoriques développés dans ce travail sont implémentés dans plusieurs algorithmes de coupes et branchements auxquels une matheuristique est également jointe pour générer rapidement des solutions réalisables. Des expérimentations intensives ont été menées via le logiciel CPLEX afin de comparer les formulations renforcées et originales. Les résultats obtenus montrent de manière convaincante la force des formulations renforcéesGiven a simple undirected graph G = (V, E) with a so-called root node r in V, a rooted tree, or an r-tree, of G is either the empty graph, or a tree containing r. If a node-capacity vector c is given, then a subgraph of G is said to be bounded if the degree of each node in the subgraph does not exceed its capacity. Let w be an edge-weight vector and p a node-price vector. The Maximum Bounded r-Tree (MBrT) problem consists of finding a bounded r-tree T = (U, F) of G such that its weight is maximized. If the capacity constraint from the MBrT problem is relaxed, we then obtain the Maximum r-Tree (MrT) problem. This dissertation contributes to the study of the MBrT problem and the MrT problem.First we introduce the problems with their definitions and complexities. We define the associated polytopes along with a formulation for each of them. We present several polynomial-time combinatorial algorithms for both the MBrT problem (and thus the MrT problem) on trees, cycles and cactus graphs. Particularly, a dynamic-programming-based algorithm is used to solve the MBrT problem on trees, whereas on cycles we reduce it to some polynomially solvable problems in three different cases. For cactus graphs, we first show that the MBrT problem can be solved in polynomial time on a so-called cactus basis, then break down the problem on any cactus graph into a series of subproblems on trees and on cactus basis.The second part of this work investigates the polyhedral structure of three polytopes associated with the MBrT problem and the MrT problem, namely Bxy(G, r, c), Bx(G, r, c) and Rx(G, r). Bxy(G, r, c) and Bx(G, r, c) are polytopes associated with the MBrT problem, where Bxy(G, r, c) considers both edge- and node-indexed variables and Bx(G, r, c) considers only edge-indexed variables. Rx(G, r) is the polytope associated with the MrT problem that only considers edge-indexed variables. For each of the three polytopes, we study their dimensions, facets as well as possible ways of decomposition. We introduce some newly discovered constraints for each polytope, and show that these new constraints allow us to characterize them on several graph classes. Specifically, we provide characterization for Bxy (G, r, c) on cactus graphs with the help of a decomposition through 1-sum. On the other hand, a TDI-system that characterizes Bx(G,r,c) is given in each case of trees and cycles. The characterization of Rx(G,r) on trees and cycles then follows as an immediate result.Finally, we discuss the separation problems for all the inequalities we have found so far, and present algorithms or cut-generation heuristics accordingly. A couple of branch-and-cut frameworks are implemented to solve the MBrT problem together with a greedy-based matheuristic. We compare the performances of the enhanced formulations with the original formulations through intensive computational test, where the results demonstrate convincingly the strength of the enhanced formulations
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Snook, Michael James. "Evolution of Tandemly Repeated Sequences." Thesis, University of Canterbury. Mathematics & Statistics, 2009. http://hdl.handle.net/10092/2661.
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Despite being found in all presently sequenced genomes, the evolution of tandemly repeated sequences has only just begun to be understood. We can represent the duplication history of tandemly repeated sequences with duplication trees. Most phylogenetic techniques need to be modified to be used on duplication trees.
Due to gene loss, it is not always possible to reconstruct the duplication history of a tandemly repeated sequence. This thesis addresses this problem by providing a polynomial-time locally optimal algorithm to reconstruct the duplication history of a tandemly repeated sequence in the presence of gene loss.
Supertree methods cannot be directly applied to duplication trees. A polynomial-time algorithm that takes a forest of ordered phylogenies and looks for a super duplication tree is presented. If such a super duplication tree is found then the algorithm constructs the super duplication tree. However, the algorithm does not always find a super duplication tree when one exists.
The SPR topological rearrangement in its current form cannot be used on duplication trees. The necessary modifications are made to an agreement forest so that the SPR operation can be used on duplication trees. This operation is called the duplication rooted subtree prune and regraft operation (DrSPR). The size of the DrSPR neighbourhood is calculated for simple duplication trees and the tree shapes that maximize and minimize this are given.
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Jax, Tim [Verfasser]. "A Rooted-Tree Based Derivation of ROW-Type Methods with Non-Exact Jacobian Entries for Index-One DAEs / Tim Jax." Wuppertal : Universitätsbibliothek Wuppertal, 2020. http://d-nb.info/1214389651/34.
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Silva, Pryscilla dos Santos Ferreira. "A post-Lie operad of rooted trees." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/55/55135/tde-10102018-164231/.
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In this thesis we propose a description of the operad defining post-Lie algebras in terms of rooted trees and we discuss some applications of such a construction. In particular, we re-derive both the free post-Lie algebra defined in [22] and the main result of the paper [8]. Furthermore, a possible extension of the concept of symmetric brace algebra to the category of the post-Lie algebras is proposed.Nessa tese propomos a descrição da operad que define as álgebras pós-Lie em termos de árvores enraizadas e discutimos algumas aplicações dessa construção. Em particular, nós obtemos novamente a álgebra pós-Lie livre definida em [22] e o resultado principal do artigo [8]. Além disso, uma possível extensão do conceito de álgebra brace simétrica à categoria de álgebras pós-Lie é apresentada.
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Artemenko, Igor. "On Weak Limits and Unimodular Measures." Thèse, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/30417.
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In this thesis, the main objects of study are probability measures on the isomorphism classes of countable, connected rooted graphs. An important class of such measures is formed by unimodular measures, which satisfy a certain equation, sometimes referred to as the intrinsic mass transport principle. The so-called law of a finite graph is an example of a unimodular measure. We say that a measure is sustained by a countable graph if the set of rooted connected components of the graph has full measure. We demonstrate several new results involving sustained unimodular measures, and provide thorough arguments for known ones. In particular, we give a criterion for unimodularity on connected graphs, deduce that connected graphs sustain at most one unimodular measure, and prove that unimodular measures sustained by disconnected graphs are convex combinations. Furthermore, we discuss weak limits of laws of finite graphs, and construct counterexamples to seemingly reasonable conjectures.
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Gebhard, Madison. "Relationships Within the Family Tree: Roots of Recidivism." Scholarship @ Claremont, 2016. http://scholarship.claremont.edu/cmc_theses/1237.
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This paper seeks to examine the correlation between family relations and habitual criminal activity. Building on previous research analyzing the power and influence of positive family environments on criminal behavior, I studied the effect of parent-child relationships as determinants of adult recidivism. My results corresponded with previous studies and implied a direct correlation between positive relationships and recidivism reduction. Furthermore, my findings support the research illustrating the effect of a person's family criminal history, level of education, and socioeconomic status on criminal behavior, which may ultimately have an effect on these influential ties between parents and children.
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Telewski, Frank W. "Determining the Germination Date of Woody Plants: A Proposed Method for Locating the Root/Shoot Interface." Tree-Ring Society, 1993. http://hdl.handle.net/10150/262369.
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A method for determining the germination dates of trees is based on wood anatomical characteristics and dendrochronology. This procedure requires destructive sampling of the tree for an extensive analysis of the zone between the roots and the trunk of the tree (root/shoot interface). The method is applicable to forest ecology and woody plant life history studies.
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Bello, Jason. "Cyclic Particle Systems on Finite Graphs and Cellular Automata on Rooted, Regular Trees and Galton-Watson Trees." The Ohio State University, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu1618833498993715.
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Van, Vleck Teresa. "Ground penetrating radar in tree root detection /." Connect to resource, 1999. http://hdl.handle.net/1811/28577.
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Schupp, James R. "The influence of time of root pruning on vegetative and reproductive growth of apple (Malus X domestica Borkh.)." Connect to resource, 1985. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1133548904.
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Laubscher, Charles Petrus. "Rooting techniques for selected tree species." Thesis, Cape Technikon, 1999. http://hdl.handle.net/20.500.11838/846.
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Thesis (MTech (Horticulture))--Cape Technikon, Cape Town, 1999Vegetative propagation techniques for rooting of cuttings of indigenous tree species, i.e. Olea europaea subsp. African, Podocarpus falcatus, Syzigium cordatum and introduced species, i.e. Acacia mearnsii, A. melanoxylon, Eucalyptus grandis and Melia azedarach were studied and improved at the Cape Technikon nursery from May 1994 to June 1998. These tree species are considered problematic since the indigenous species produce unwanted fruits in urban areas which attract frugivores, while the introduced species are a threat to indigenous vegetation and natural habitats, though they are of great commercial value. The progress in mutation breeding of sexual sterility in most of the problematic species created a need to propagate them vegetatively. Without cloning of seedless species, their beauty and economic value to South Africa will be lost, as the indigenous species will be neglected, while invasive species will continue to threaten the natural habitat of indigenous species. Experiments were conducted to test age, type and length of cuttings, environmental factors, growth season, hormone application, various treatments and rooting media for each of these species. This study showed that relatively few publications relevant to the vegetative propagation of indigenous tree species are available. However, some introduced species, e.g. Eucalyptus grandis, are propagated successfully for commercial forestry purposes. Ficus sur and Syzicium cordatum showed the highest rooting success, i.e. 85-90%, followed by Olea europaea subsp. africana (75-80%), and Podocarpus falcatus (60%). The introduced species showed no rooting success, however, callusing in Eucalyptus grandis (35-61%), and Melia azedarach (50%), and survival rates in Acacia mearnsii (10%) and A. melanoxylon (20%) were achieved. Treatments, i.e. etiolation, placing plants under stress, sealing basal stems of cuttings, and fungicide treatments all showed positive results in promoting callusing success. The study showed that rooting success in individual species are directly related to the growth stage of parent plants as well as the season during which the cuttings were taken. With progress towards successful vegetative propagation of sterile problem plant species, propagators and horticulturists can in future apply these improved techniques. These plants will then continue to supply timber, fire wood and improve aesthetics in the South African urban environment.
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Layman, Rachel Montgomery. "Rehabilitation of Severely Compacted Urban Soil to Improve Tree Establishment and Growth." Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/76910.
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Land development restricts tree growth by damaging soil structure and removing organic matter. Mechanical loosening and organic amendment may improve soil physical properties and tree establishment and growth. Effects of typical post-construction practice and improved methods of soil restoration on tree growth and soil properties were evaluated over two years. Treatments included undisturbed soil (UN); minimum effort (ME) (10 cm topsoil); enhanced topsoil (ET) (ME + rototilling); and profile rebuilding (PR) (compost, subsoiling, topsoil and rototilling). Pretreatment included removing topsoil and compacting subsoil to 1.95 g/cm3 bulk density. Acer rubrum L. (red maple), Quercus bicolor Willd. (swamp white oak), Ulmus 'Morton' (Ulmus japonica (Rehd.) Sarg. x Ulmus wilsoniana Schneid.) (Accolade® elm), Prunus 'First Lady' (Prunus xincam x Prunus campanulata) L. and Quercus macrocarpa Michx. (bur oak) were planted in each plot. The PR treatment reduced soil bulk density at 15-20 cm depth and increased soil C/N ratio, pH, and CEC. Mean canopy projection and cross-sectional trunk area in PR plots ranged from 32% to 226% and 16% to 71% greater, respectively, than those in ME plots. PR treatment increased Q. bicolor photosynthesis rates. Greater root presence was observed in deeper soil layers of ET and PR treatments for A. rubrum and of UN and PR for Q. bicolor; root distribution was not measured for other species. Rehabilitation improved soil physical properties and tree growth after two years. Species variation in growth rate and environmental tolerance appeared to influence early growth treatment effects. Long-term data is needed to fully understand effects of soil rehabilitation.Master of Science
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Grossman, Christopher (Christopher M. ). "Design of a tree root ball transporting device." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/40420.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007.Includes bibliographical references (leaf 20).
Tree root balls from nurseries are often too heavy for one or two people to lift and plant, but powerful machinery can be expensive for small landscaping organizations or the weekend home gardener. This thesis intends to document the market for such a device and describe why the current products don't meet the specific requirements of the groups listed. The progress of designing a new device is illustrated from the initial constraints of the product to the evolution of a final prototype. Key aspects of the final design are emphasized and the complete process of transporting a tree root ball with the prototype to the desired hole is described. As future work after construction, customer feedback and usability testing can be collected to ensure that a valuable product will enter the market and fulfill the needs of landscapers in all parts of the country.
by Christopher Grossman.
S.B.
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Ahmed, Elsayed. "Groups Generated by Automata Arising from Transformations of the Boundaries of Rooted Trees." Scholar Commons, 2018. https://scholarcommons.usf.edu/etd/7459.
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In this dissertation we study groups of automorphisms of rooted trees arising from the transformations of the boundaries of these trees. The boundary of every regular rooted tree can be endowed with various algebraic structures. The transformations of these algebraic structures under certain conditions induce endomorphisms or automorphisms of the tree itself that can be described using the language of Mealy automata. This connection can be used to study boundarytransformations using the propertiesof the induced endomorphisms, or vice versa.
We concentrate on two ways to interpret the boundary of the rooted d-regular tree. In the first approach discussed in detail in Chapter 3 we treat it as the ring Zd of d-adic integers. This is achieved by naturally identifying the nth level of the rooted d-ary tree with the ring Z/(dnZ). Under this interpretation we study transformations of Zd induced by polynomials in Z[x]. We show that they always induce endomorphisms of the tree, completely describe these endomorphisms using the language of automata and show that all of their sections are again induced by polynomials in Z[x] of the same degree. In the case of permutational polynomials acting on Zd by bijections the induced endomorphisms are automorphisms of the tree. For d = 2 such polynomials were completely characterized by Rivest in [Riv01]. As our main application we utilize the result of Rivest to derive the conditions on the coefficients of a permutational polynomial f(x) ∈ Z[x] that are necessary and sufficient for f to induce a level transitive automorphism of the binary tree, which is equivalent to the ergodicity of the action of f(x) on Z2 with respect to the normalized Haar measure. Such polynomials have applications in cryptography and are used in certain generators of random numbers.
In the second approach, to be discussed in Chapter 4, we treat the boundary of the rooted binary tree as the ring (Z/2Z)[[t]] of formal power series over Z/2Z. This view allowed us to completely describe the structure of a certain group generated by a 4-state 2-letter bireversible automaton. Namely, we show that it is isomorphic to the lamplighter group (Z/2Z)2 ≀ Z of rank two. We show that the action of the generators of this group on the boundary of the tree can be induced by affine transformations of (Z/2Z)[[t]]. To our best knowledge, this is the first realization of the rank 2 lamplighter group by a bireversible automaton.
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Hettasch, Georg. "Optimization of fir-tree-type turbine blade roots using photoelasticity." Thesis, Stellenbosch : University of Stellenbosch, 1992. http://hdl.handle.net/10019.1/993.
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Thesis (MEng.)-- University of Stellenbosch, 1992.
140 leaves on single pages, preliminary pages i-xi and numbered pages 1-113. Includes bibliography. Digitized at 600 dpi grayscale to pdf format (OCR),using an Bizhub 250 Konica Minolta Scanner and at 300 dpi grayscale to pdf format (OCR), using a Hp Scanjet 8250 Scanner.Thesis (MEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 1992
ENGLISH ABSTRACT: The large variety of turbo-machinery blade root geometries in use in industry prompted the question if a optimum geometry could be found. An optimum blade root was defined as a root with a practical geometry which, when loaded, returns the minimum fillet stress concentration factor. A literature survey on the subject provided guidelines but very little real data to work from. An initial optimization was carried out using a formula developed by Heywood to determine loaded projection fillet stresses. The method was found to produce unsatisfactory results, prompting a photoelastic investigation. This experimental optimization was conducted in two stages. A single tang defined load stage and a single tang in-rotor stage which modeled the practical situation. The defined load stage was undertaken in three phases. The first phase was a preliminary investigation, the second phase was a parameter optimization and the third phase was a geometric optimization based on a material utilization optimization. This material optimization approach produced good results. From these experiments a practical optimum geometry was defined. A mathematical model which predicts the fillet stress concentration factor for a given root geometry is presented. The effect of expanding the single tang optimum to a three tang root was examined.
AFRIKAANSE OPSOMMING: Die groot verskeidenheid lemwortelgeometrieë wat in turbomasjiene gebruik word het die vraag na 'n optimum geometrie laat ontstaan. Vir hierdie ondersoek is 'n optimum geometrie gedefineer as 'n praktiese geometrie wat, as dit belas word, die mimimum vloeistukspanningskonsentrasiefaktor laat ontstaan. 'n Literatuur studie het riglyne aan die navorsing gegee maar het wynig spesifieke en bruikbare data opgelewer. Die eerste optimering is met die Heywood formule, wat vloeistukspannings in belaste projeksies bepaal, aangepak. Die metode het nie bevredigende resultate opgelewer nie. 'n Fotoelastiese ondersoek het die basis vir verdere optimeering gevorm. Hierdie eksperimentele optimering is in twee stappe onderneem. 'n Enkelhaak gedefineerde lasgedeelte en 'n enkelhaak in-rotor gedeelte het die praktiese situasie gemodeleer. Die gedefineerde lasgedeelte is in drie fases opgedeel. Die eerste fase was n voorlopige ondersoek. Die tweede fase was 'n parameter optimering. 'n Geometrie optimering gebasseer op 'n materiaal benuttings minimering het die derde fase uitgemaak. Die materiaal optimerings benadering het goeie resultate opgelewer. Vanuit hierdie eksperimente is 'n optimum praktiese geometrie bepaal. 'n Wiskundige model is ontwikkel, wat die vloeistukspanningskonsentrasiefaktor vir 'n gegewe wortelgeometrie voorspel. Die resultaat van 'n geometriese uitbreiding van die enkelhaaklemwortel na 'n driehaaklemwortel op die spanningsverdeling is ondersoek.
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Alvey, Alexis A. "Efficacy and Effect of Tree Stabilization Systems On Landscape Tree Growth and Establishment." Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/33160.
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Various forms of staking, guying, and root ball anchoring are used to prevent post-transplant tree destabilization in the landscape, but little scientific evidence exists to support this practice. This experiment tested the efficacy of three generic tree stabilization systems (TSS) and their effect on tree growth and establishment. In spring 2006, 48 balled and burlapped, 6.4 cm (2.5 inch) diameter, white ash (Fraxinus americana L. â Autumn Purpleâ ) were transplanted to a field site in Blacksburg, VA. At planting, one of four TSS treatments (staking, guying, root ball anchoring, or non-stabilized) was installed on each tree. After five weeks, tree pulling tests were conducted on 24 trees to simulate a strong wind load using a cable winch mounted to a skid-steer loader. After one growing season, change in tree height, trunk diameter, and trunk taper were compared among the 24 remaining trees. Soil cores were taken and the length, diameter, and dry weight of roots within the cores were analyzed. TSS were then removed and tree pulling tests were conducted using the same method.
The five week tests showed that destabilization was significantly greater for non-stabilized trees (mean of 16 degrees from vertical) than for trees with TSS (all means less than 3 degrees from vertical). Yet after one growing season, there were no significant differences among any treatments in tree stability. We conclude that in locations with high wind speeds, TSS may be necessary for trees similar to those in our study, but only for a very short period of time.
Results also indicated that staking, guying, and root ball anchoring were equally effective, very robust, very durable, caused no tree injuries, and did not impact tree growth or establishment after one growing season. Practical considerations may therefore play a more important role when choosing which TSS to use. Although the time required for TSS installation was similar for each system, staking was more than twice as expensive as guying or root ball anchoring.
Master of Science
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Tetsumura, Takuya. "PRODUCTION AND FIELD EVALUATION OF OWN-ROOTED TREES OF JAPANESE PERSIMMON (Diospyros kaki Thunb.)." Kyoto University, 2001. http://hdl.handle.net/2433/151641.
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本文データは平成22年度国立国会図書館の学位論文(博士)のデジタル化実施により作成された画像ファイルを基にpdf変換したものであるKyoto University (京都大学)
0048
新制・論文博士
博士(農学)
乙第10593号
論農博第2346号
新制||農||817(附属図書館)
学位論文||H13||N3493(農学部図書室)
UT51-2001-A785
(主査)教授 杉浦 明, 教授 矢澤 進, 教授 河瀨 晃四郎
学位規則第4条第2項該当
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Grünig, Christoph. "Population biology of the tree-root endophyte Phialocephala fortinii /." [Zürich], 2003. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=15313.
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Makita, Naoki. "Study on Tree Root Respiration in Forest Carbon Dynamics." Kyoto University, 2013. http://hdl.handle.net/2433/175076.
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Kyoto University (京都大学)0048
新制・課程博士
博士(農学)
甲第17647号
農博第2009号
新制||農||1013(附属図書館)
学位論文||H25||N4768(農学部図書室)
30413
京都大学大学院農学研究科地域環境科学専攻
(主査)教授 谷 誠, 教授 北山 兼弘, 教授 大澤 晃
学位規則第4条第1項該当
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Quillen, Brian G. "Democracy - a tree without roots on the steppes of Central Asia." Thesis, Monterey, Calif. : Naval Postgraduate School, 2006. http://bosun.nps.edu/uhtbin/hyperion.exe/06Dec%5FQuillen.pdf.
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Thesis (M.A. in National Security Affairs)--Naval Postgraduate School, December 2006.Thesis Advisor(s): Mikhail Tsypkin. "December 2006." Includes bibliographical references (p. 83-90). Also available in print.
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Rowe, Edwin Christopher. "The safety-net role of tree roots in hedgerow intercropping systems." Thesis, Imperial College London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313884.
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Skophammer, Ryan Gabriel. "Uncovering deep prokaryotic relationships to root the tree of life." Diss., Restricted to subscribing institutions, 2009. http://proquest.umi.com/pqdweb?did=1930895841&sid=35&Fmt=2&clientId=1564&RQT=309&VName=PQD.
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Tamang, Bijay. "Tree windbreak function, root distribution and biomass production in Florida." [Gainesville, Fla.] : University of Florida, 2009. http://purl.fcla.edu/fcla/etd/UFE0041134.
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Liu, Lumin. "Stomatal and leaf growth responses to water deficit in willow." Thesis, University of Aberdeen, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297564.
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Abscisic acid (ABA) was synthesised in dehydrating leaves and roots of willow (Salix dasyclados) and exogenous ABA in the xylem stream was shown to cause decreases in stomatal conductance. A transient decrease in leaf water potential occurred if water was entirely withheld from roots on one side of a willow plant. This was avoided if roots from all sides of the plant were watered and only root tips were allowed to dehydrate. Partial stomatal closure and decreased leaf extension rate then occurred without any initial perturbation in leaf water potential or leaf ABA. The drying event was associated with an increased content of ABA in root tips and xylem sap. The effects were reversible on either rewatering or excision of the affected root tips. It was concluded that partial dehydration of root tips caused partial stomatal closure and decreased leaf extension, and that changes in the ABA content of root tips and the xylem sap were consistent with a possible causal role for root-sourced ABA in the regulation of leaf physiology in response to root water deficit. Stem-girdling experiments indicated that a major pathway of ABA transport, between leaves on different stems in the shoot system, was in the phloem, without an apparent involvement of transport in the xylem. Damage to the shoot apex caused an increase in stomatal conductance. This was associated with a decreased content of ABA in the xylem sap and in fully extended leaves. It is suggested that these changes may have been associated with a possible import of ABA from mature leaves into the growth sites of axillary shoots. Results are discussed within the context of water deficit and the growth and survival of individual stems in a willow plantation.
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Areghan, Joseph I. "Settlement Behavior of a Sandy Loam Due to Suction Changes Associated with Simulated Artificial Tree Roots." Thesis, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/23514.
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Shallow foundations rested on Leda clay that are widely distributed in Eastern Canada exhibit shrinkage characteristics and are prone to differential settlements. Due to this reason, significant repairs are necessary to the foundations and basements of residential structures constructed in Leda clay deposits. Differential settlements are commonly attributed to the changes in the natural water content of soils associated with water infiltration, evaporation or plant transpiration (i.e., tree-roots-suction). Various research studies have been undertaken to estimate the possible settlements of shallow foundations associated with the water infiltration or evaporation. Several thumb rules have been proposed through research studies, providing recommendations with respect to the distance at which trees must be planted as a function of their heights at maturity such that differential settlements can be avoided. However, limited studies have been carried out to estimate or model the settlements of shallow foundations taking into account the influence of tree-roots-suction.
In the present research program, a comprehensive experimental study regarding the deformation characteristics of a sandy loam soil from Ottawa due to tree-root-suction is undertaken, using specially designed equipment. The study has been undertaken using a sandy loam soil so that the testing program can be conducted in a shorter period of time. An artificial rooting system (ARS) was designed and placed in a specially designed tank at the University of Ottawa to simulate tree-roots-suction and measure soil surface settlements associated with a decrease in natural water content (or increase in soil suction) using particle image velocimetry (PIV) technique. The ARS consists of an artificial root, suction generator, matric suction and volumetric water content monitoring devices. The variation of matric suction and volumetric water content are monitored at various depths using the instrumentation of the ARS. Based on the results of the experimental studies, a methodology is proposed to model the settlement behaviour of sandy loam soils due to suction from ARS, using commercial finite element software, SEEP/W and SIGMA/W (i.e. software package of GeoStudio 2007). The study offers a reasonably good comparison between the measured surface settlements and those estimated using the finite element modelling analysis. The modelling methodology presented in this thesis is promising and may be extended for estimating the settlement behaviour associated with the tree roots suction of Leda clay deposits and to other soils.
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McDonald, Morag Anne. "The use of a root bioassay to indicate the phosphorus status of forest trees." Thesis, University of Edinburgh, 1987. http://hdl.handle.net/1842/12611.
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Hollstein, R. W. M. "The dependence of mycorrhrizae in Sitka spruce roots, on the availability of phosphorus in serpentine and basaltic soils." Thesis, University of Aberdeen, 1986. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU006854.
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The nature and occurrence of mycorrhizal associations, with particular reference to the anatomy, carbohydrate physiology, plant mineral nutrition and occurrence of ectomycorrhizae (ECM), is discussed. The ecology and forest relations of Picea sitchensis - the Sitka spruce concludes the literature review. Identification of areas of good and poor Sitka growth on related soils and the quantification of their ECM status, investigation of the effect of phosphate addition to Sitka seedlings in pots, subsequent and changes to their ECM status, and the effects of soluble aluminium on phosphate nutrition of Sitka seedlings, the collation of results and relation back to the field situation were carried out as experimental work. Field sites were identified and described in terms of geology, soils, field ECM status, forest productivity and nutrient status. Three pot experiments were carried out. The 1st investigated the effects of phosphate application on ECM Sitka seedlings in soil from the field sites; the 2nd investigated the effects of phosphate application to ECM and non-mycorrhizal (NM) seedlings in compost; and the 3rd investigated the affects of application of Al-citrate to ECM and NM seedlings in compost containing high and low levels of phosphate. The results obtained were described and discussed in the context of a model of the factors affecting plant response to the soil environment. The field ECM development representing a considerable drain on the carbohydrate economy of the field sites was to some extent duplicated in the greenhouse. The possible decrease in importance of this drain was illustrated by phosphate application, but was increased by addition of Al-citrate. A previously unrecorded ECM-enhanced uptake of Manganese was reported. The importance of phosphate in the soils under discussion was emphasised, and possible further work suggested.
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Elkink, Deb. "Roots and branches the symbol of the tree in the imagination of G.K. Chesterton /." Theological Research Exchange Network (TREN), 2001. http://www.tren.com.
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Tanner, Shann C. "Peach tree root demography and soil microbial characteristics in peach replant soils." Connect to this title online, 2007. http://etd.lib.clemson.edu/documents/1202409146/.
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Haigh, Nathan S. "Resolving the deep phylogeny of the eukaryotic tree and locating its root." Thesis, University of York, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.428453.
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Hernandez-Leos, Bertha Alicia. "Water Uptake, Water Relations, Tree Growth, and Root Distribution under Herbaceous Competition." DigitalCommons@USU, 1998. https://digitalcommons.usu.edu/etd/6573.
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There are numerous situations where trees are grown together with herbaceous plants. In these situations there will be some degree of competition between their root zones, depending on the water content of the soils and crop and tree root distribution . Two studies were conducted : the first with maple (Acer platanoides) grown in turf grass, and the second with willow (Salix matsudana) grown in more deeply rooted barley . The objectives of this study were to quantify the effect of herbaceous competition of potential tree water stress under irrigation and when the soil is allowed to dry-down . Soil water uptake was measured in both studies to 1.2 m depth and outwards to 1.2-2.10 m away from the tree . In the maple-turf grass study, water content was measured in a single line away from the tree , while four lines covering a quadrant of the surface area were measured in willow . Water relations stomatal conductance and water potential, and tree growth were also monitored in both studies. Water uptake in turf plots was statistically different from mulch plots by depth and distance during three seasons. Water uptake was greatest at 0-60 cm depth in the turf treatments compared with mulch treatments. Soil water in mulched plots decreased slowly during the growing season. There were no statistical differences between bare soil and barley competition water uptake after soil surface water was depleted.
There were marked differences in tree root characteristics as a result of competition from turf or barley roots. The root systems of maples in the mulch and willow in bare soil extended laterally and fine roots were evident. Tree roots extended deeper and fine root were reduced under competition from turf and barley. Trees growing with turf and barley had fewer roots in the top 0.3 m soil surface while trees in mulch and bare soil had more and greater diameter roots at the same depth. Early in the season, when water content is high, root competition for water was not evident, and late in the season after turf roots and barley had depleted the soil water, trees exhibited more negative predawn leaf water potential and less stomatal conductance in response to water stress during a soil dry-down period. Tree growth was measured periodically during 1994, 1995, and 1996. Leaf area and stem growth comparisons showed a significant increase in size as a result of the absence of competition in both species, with mulch and bare soil treatments. Leaf area in mulched trees was twice that in turf treatments. In summary, we found that competition resulted in deeper tree root growth and less top growth in the presence of herbaceous competitors.
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Collins, Joshua Stewart. "Rekernelisation Algorithms in Hybrid Phylogenies." Thesis, University of Canterbury. Mathematics and Statistics, 2009. http://hdl.handle.net/10092/2852.
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It has become well known that an evolutionary tree is inadequate to represent fully the history of life. Two possible ways of dealing with this are the rooted subtree prune and regraft distance between a pair of trees, which measures how different they are, and the slightly more biologically sound hybridisation number of a set of trees that attempts to determine the minimum number of hybrid events that must have occurred for a given set of evolutionary trees. When characterised via agreement forests both problems are, although NP hard, fixed parameter tractable---meaning the problem can be converted to a similar problem with a smaller input size. This thesis investigates ways of improving existing algorithms for calculating the minimum rooted subtree prune and regraft distance and hybridisation number for a pair or, in the latter case, set of trees. In both cases a technique is used that allows the problem to be rekernelised during the run of the program. Another, less effective method, is also looked at which finds the rooted subtree prune and regraft distance or hybridisation number solely on what cannot be contained within any agreement forest. Additionally the characterisation of the minimum rooted subtree prune and regraft distance via maximum agreement forests is extended to non-binary trees and the hybridisation number of a set of phylogenetic trees is extended to unrooted trees.
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Lehto, Tarja Helena. "Role of mycorrhizas in drought resistance of Sitka spruce seedlings." Thesis, University of Edinburgh, 1989. http://hdl.handle.net/1842/11045.
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Browning, Robin Eileen. "Evolution of roots." CONNECT TO THIS TITLE ONLINE, 2008. http://etd.lib.umt.edu/theses/available/etd-08282008-142232/.
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Wambsganß, Janna [Verfasser], Jürgen [Akademischer Betreuer] Bauhus, and Michael [Akademischer Betreuer] Scherer-Lorenzen. "Tree diversity effects on fine-root soil exploitation and decomposition in European forests." Freiburg : Universität, 2021. http://d-nb.info/1236550919/34.
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Altinalmazis, kondylis Andreas. "Tree diversity effects on root production, decomposition and nutrient cycling under global change." Thesis, Bordeaux, 2021. http://www.theses.fr/2021BORD0067.
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L'hypothèse de l'assurance prévoit que les forêts composées de mélanges d'espèces d'arbres pourraient mieux résister aux conditions environnementales stressantes que les forêts composées d'une seule espèce d'arbre. La majorité des travaux antérieurs ont testé cette hypothèse en se focalisant sur la productivité et les variables de réponse associées sans prendre en compte les processus souterrains. L’objectif principal de ma thèse était d’étudier l’effet de la diversité des espèces d’arbres sur les processus souterrains impliqués dans la décomposition des racines à travers des gradients climatiques. J'ai émis l'hypothèse que le mélange d'espèces ayant des systèmes racinaires contrastés entraînerait une faible compétition souterraine, et se traduirait par la production de plus biomasse de racines fines. En outre, j'ai émis l'hypothèse que les racines ayant des caractéristiques chimiques et morphologiques contrastées dans les peuplements mixtes se décomposent plus rapidement. Dans des conditions de stress hydrique, j'ai émis l'hypothèse d'une décomposition plus lente mais d’une atténuation des mélanges d'arbres sur la décomposition en raison de l'amélioration des conditions micro-environnementales. Pour tester ces hypothèses, j'ai examiné la variation des caractéristiques fonctionnelles des racines et leurs conséquences sur les flux de C, N et P à l'échelle de l'écosystème à travers l’étude de : 1) la ségrégation verticale des racines et la biomasse des racines fines, 2) la dynamique des racines fines et les flux de nutriments associés et 3) la décomposition des racines fines et des feuilles mortes. Dans ce cadre, trois deux expériences de terrain ont été réalisé, l'une avec une expérience de plantation d'arbres de 10 ans avec du bouleau et du pin près de Bordeaux (expérience ORPHEE), la seconde le long d'un gradient latitudinal de forêts de hêtres matures dans les Alpes françaises (expérience BIOPROFOR).Les résultats obtenus montrent que les racines de bouleaux et de pins présentaient une distribution verticale similaire et une biomasse souterraine similaire de racines dans les mélanges d'arbres par rapport aux monocultures, contrairement à ma première hypothèse. Cependant, l'attribution plus importante du pin mais pas du bouleau à la croissance des racines dans les horizons du sol supérieur dans des conditions moins limitatives en eau suggère des conditions localement favorables qui peuvent conduire à une compétition asymétrique à la profondeur du sol. De plus, la production et la décomposition des racines fines étaient similaires dans les mélanges et dans les monocultures, en contradiction avec ma deuxième hypothèse. Il est intéressant de noter que les racines de bouleau, mais pas les racines de pin, ont libéré du P pendant leur décomposition, ce qui suggère un rôle important du bouleau dans le cycle du P et pour la nutrition en P des arbres sur ces sols sableux limités en P. Conformément à ma troisième hypothèse, j'ai observé une décomposition plus lente de la litière de feuilles et des racines fines en réponse à une sécheresse estivale prolongée, tout au long du gradient latitudinal dans les Alpes. Cependant, cette décomposition plus lente sous la sécheresse n'a pas été atténuée dans les peuplements forestiers à essences mixtes par rapport aux peuplements à essences uniques. Il est intéressant de noter qu’il y a une libération nette d'azote dans les racines fines en décomposition mais pas dans la litière de feuilles en décomposition, ce qui suggère un rôle distinct des racines fines dans le cycle de l'azote. En conclusion, j'ai constaté que le mélange des espèces d'arbres n'atténue pas les effets négatifs du changement climatique. Cette thèse démontre que la promotion de mélanges peut toujours être bénéfique pour au moins une des espèces d'arbres mélangées, par l'ajout d'espèces, car une espèce d'arbre peut en faciliter la nutrition minérale d’une autre par des flux souterrains de N et de PThe insurance hypothesis predicts that forests with tree species mixtures may resist better to stressful environmental conditions than forests composed of only one tree species. Most of the currently available literature tested this hypothesis for aboveground productivity and its related response variables, but less is known about belowground processes. In my PhD thesis, I studied the drivers of belowground productivity and decomposition across climatic gradients and how they are affected by tree mixtures. I hypothesized that mixing of tree species with contrasting rooting patterns and fine root morphologies, would result in a release of competitive pressure belowground, and translate into higher fine root standing biomass and increased fine root productivity. Moreover, I hypothesized that roots with contrasting chemical and morphological characteristics in mixed stands would decompose faster, which may be particularly important under nutrient-limited conditions. Under water-limiting conditions, such as during extreme summer drought, I hypothesized overall slower decomposition but an attenuating effect of tree mixtures on decomposition due to improved micro-environmental conditions, in particular for leaves, since roots decompose in a more buffered soil environment. To test these hypotheses I examined the variation in tree root functional traits (across- and within-species), and its consequences for fluxes of C, N and P at the ecosystem scale. I addressed three main objectives and associated research questions to quantify the interactive effect of tree mixtures and climate on: 1) vertical root segregation and fine root standing biomass, 2) fine root dynamics and their associated nutrient fluxes and 3) fine root- and leaf litter decomposition. I could benefit from two different field experiments for my work, one with a 10-year-old tree-plantation experiment with birch and pine close to Bordeaux (ORPHEE experiment), the second along a latitudinal gradient of mature beech forests in the French Alps (BIOPROFOR experiment).I observed that roots from the birch and pine tree-plantation showed similar vertical distribution and similar belowground root standing biomass in tree mixtures compared to monocultures, contrary to my first hypothesis. However, the greater allocation of pine but not of birch to root growth within the top soil horizons under less water-limiting conditions suggests locally favourable conditions that may lead to soil depth-specific asymmetric competition. In the same experiment, fine root production and decomposition were similar in mixtures and in monocultures, in contradiction with my second hypothesis. Moreover, I did not observe any interactive effects of tree mixtures with stand density or water availability. Interestingly though, birch roots, but not pine roots released P during root decomposition, which suggests an important role of birch in the P-cycle and for P nutrition of trees on these P-limited sandy soils. In line with my third hypothesis, I observed a slower decomposition of leaf litter and fine roots in response to reinforced and prolonged summer drought, irrespective of the position along the latitudinal gradient in the Alps. However, this slower decomposition under drought was not attenuated in forest stands with mixed tree species compared to single species stands. Compared to leaf litter, fine roots decomposed slower and released less C. Interestingly, I found a net N release in decomposing fine roots but not in decomposing leaf litter, which suggests a distinct role of fine roots in the N cycle. In conclusion, I found that mixing tree species did not attenuate negative effects of climate change. However, this thesis demonstrates that promoting mixtures can still be beneficial for at least one of the admixed tree species, through species addition (i.e., complementing one tree species with another tree species), as one tree species may facilitate another via belowground fluxes of N and P
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Wambsganss, Janna [Verfasser], Jürgen [Akademischer Betreuer] Bauhus, and Michael [Akademischer Betreuer] Scherer-Lorenzen. "Tree diversity effects on fine-root soil exploitation and decomposition in European forests." Freiburg : Universität, 2021. http://d-nb.info/1236550919/34.
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Ayadi, Mohamed. "Propriétés algébriques et combinatoires des espaces topologiques finis." Electronic Thesis or Diss., Université Clermont Auvergne (2021-...), 2022. http://www.theses.fr/2022UCFAC106.
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Schupp, James Rawlinson. "Physiological responses of apple trees to root pruning /." The Ohio State University, 1988. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487590702990348.
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Livesley, Stephen. "The distribution and dynamics of roots and soil nitrogen and water in tree row agroforestry systems." Thesis, University of Reading, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285967.
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Misra, Dinesh. "Early tree-soil-root relationships of Prosopis, Eucalyptus, and Azadirachta planted on sodic soils." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0026/MQ50395.pdf.
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Sande, Bueno Dickens. "Pollarding and root pruning as management options for tree-crop competition and firewood production." Thesis, Stellenbosch : University of Stellenbosch, 2003. http://hdl.handle.net/10019.1/2355.
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Thesis (MScFor) (Forest and Wood Science)--University of Stellenbosch, 2003.Planting of upperstorey trees along boundaries has been introduced in KabaleUganda with good reception from local farmers. Trees have been planted along agricultural fields, but both Alnus acuminata and Grew/lea robusta out-compete food crops. Managing competition between trees and crops for water, light, and nutrients to the benefit of farmers is a determinant of successful agroforestry. The scarcity and fragmentation of farmland coupled with the hilly nature of Kabale, highlights the need to address the question of tree-crop competition for resources if the technology of on-farm tree planting is to be widely disseminated and adopted in its different guises. Five-year old trees of A acuminata and G. robusta were subjected to treatments of pollarding, or a combination of pollarding and one side root pruning and compared with unpruned controls. The objectives were to assess their potential in reducing competition with food crops and providing firewood to farmers as well as their effects on tree growth. Pollarding has many benefits to farmers because it provides firewood and stakes for climbing beans, it reduces competition for resources between trees and crops and enables continued tree planting on-farm. Continued on-farm tree planting alleviates problems associated with limited land and contributes to environmental resilience. To ensure this, effect of pollarding and root pruning of upperstorey boundary trees of A acuminata and G. robusta was tested on 12 farmers' fields in Kabale. Food crops (beans and maize) grown in the sequence beans-maize-beans, grew very well at less than 50 em from trees that had been pollarded and root pruned one side. In general, pooled data from 12 sites over 5 m away from trees indicated that a combination of pollarding and root pruning increased bean yield by 240% and maize by 154%, while pollarding alone increased bean yield by 181% and maize yield was increased by 123% in comparison to non-pruned trees. However, pollarding and root pruning treatments reduced tree growth rates.Notable was more competition with crops by A. acuminata than by G. robusta. This was attributed to differences in root architecture, diameter at breast height (dbh) sizes, crown spread and crown density between the two species. Five-year-old A. acuminata had bigger dbh (12.40 cm), wider crown spread (6 m) and a dense crown, while G. robusta had dbh 10.82 em, 3 m crown spread and a light crown. A. acuminata also had more branches per tree (34) compared to G. robusta with only 25. These factors influence water uptake, light penetration through the canopy and transpiration rates, and thus affect tree-food crop competition. It is concluded that pollarding and root pruning have a great potential to reduce tree-crop competition, thereby paving the way for continued on-farm tree planting. The effect of pollarding on timber quality, moisture seepage into timber through the cut surface, if any, and the extent of its damage are areas for further research. The rate of root recovery is also to be followed closely to determine an appropriate frequency for cutting back of roots to recommend to farmers how often they need to prune their trees. It is also suggested that a thorough study be conducted on the amount of water uptake from the soil by each of the species Alnus acuminata and Grevillea robusta. This will help further explain the differences in competition between the two species.
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Ju, Shu. "Model of Strategies of Tree Carbon Allocation to Roots, Foliage and Defense in Relation to Environmental Conditions." Scholarly Repository, 2010. http://scholarlyrepository.miami.edu/oa_dissertations/377.
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Three general questions are studied regarding plant carbon allocation strategies. (1) The R* Rule states that the superior competitor in a plant community should exclude all others by minimizing available limiting nutrient concentration below the level needed for survival of its competitors. I asked whether a plant carbon allocation strategy that minimizes the concentration of available limiting nutrient is consistent with Lotka's (1922) conjecture that ecosystems should evolve to maximize total energy flow (primary production). (2) In landscapes such as the Everglades, areas of landscape with higher energy flow (primary production) than the surrounding area also have higher available concentrations of limiting nutrient, rather than lower concentrations, which might be expected from the R* rule. I asked whether this pattern can be explained. (3) I asked how optimal allocation of carbon to plant defense allocation strategies might depend on different conditions of nutrient availability, shading, and herbivory. To address all three questions, I used a model revised from the G'DAY model (Comins and McMurtrie 1993) to study tree allocation of carbon resources between foliage, roots, and defense. With regard to the first question, I found that the allocation strategy that leads to minimum concentration of available nutrients is the same as the strategy for which energy flux to roots, rather than total energy flux, is maximized. Further, I found that the strategy that was competitively dominant was neither the strategy for which total energy flux was maximized, nor that for which available nutrient concentration was minimized. With regard to the second question, I found that, if a patch of vegetation on a landscape is able to capture nutrients from the surrounding landscape, for example, through relatively higher evapotranspiration, it could lead to the opposite of what is expected from the R* rule; that is, available limiting nutrient concentration is maximized when carbon flow to the roots is maximized. With regard to the last question, I found that under high herbivory, the optimal plant strategy for allocation of carbon to defense depends on the available nutrient concentration and amount of radiation to the plant, in agreement with some theoretical predictions.
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Finegan, Donal Michael. "The production and removal of anaerobic metabolites from flooded tree roots, with special reference to Pinus contorta." Thesis, University of St Andrews, 1989. http://hdl.handle.net/10023/14496.
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The production and removal of anaerobiotic compounds, principally ethanol from flooded tree roots was examined in lodgepole pine (Pinus contorta) from known provenances. Contrary to earlier suggestions, the gaseous pathway, with ethanol exiting from the tree through the lenticels, removes only a very small proportion (less than 0.2%) of the ethanol generated in the flooded roots. The transpiration stream provides the major route for ethanol transport from the roots. Although the lenticels do not contribute significantly to the removal of ethanol from tree roots, analysis of the gas exiting from them provides a sensitive indicator of the existence of oxygen within roots. Within the xylem sap and root tissue, changes in ethanol, amino acid (alanine, alpha amino butyrate and glutamine) and organic acid (malate and shikimate) composition under flooded conditions were analysed and discussed. For example during flooding glutamine (the major constituent amino acid) was shown to decrease, and alanine and alpha amino butyrate to increase. From the data obtained it was concluded that the health and the metabolism of the root tissue during flooding can be diagnosed by examination of the xylem sap.
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Rakonczay, Zoltán. "Characterizing the Respiration of Stems and Roots of Three Hardwood Tree Species in the Great Smoky Mountains." Diss., Virginia Tech, 1997. http://hdl.handle.net/10919/30624.
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Carbon dioxide efflux rates (CER) of stems and roots of overstory and understory black cherry (Prunus serotina Ehrh., BC), red maple (Acer rubrum L., RM) and northern red oak (Quercus rubra L., RO) trees were monitored over two growing seasons at two contrasting sites in the Great Smoky Mountains to investigate diurnal and seasonal patterns in respiration and to develop prediction models based on environmental and plant parameters.
CER of small roots (d<0-8 mm) was measured with a newly developed system which allows periodic in situ measurements by using permanently installed flexible cuvettes. Temperature-adjusted CER of roots showed no diel variation. The moderate long-term changes occurred simultaneously in all species and size classes, suggesting that they were driven mostly by environmental factors. Mean root CER ranged from 0.5 to 4.0 nmol g⁻¹ d.w. s⁻¹. Rates were up to six times higher for fine roots (d<2.0 mm) than for coarse roots.
CER (per unit length) of boles (d>10 cm) and twigs (d<2 cm) was related to diameter by the function lnCER = a+D·lnd, with D between 1.2 and 1.8. A new, scale-invariant measure of CER, based on D, facilitated comparisons across diameters. Q₁₀ varied with the method of determination, and it was higher in spring (1.8-2.5) than in autumn (1.4-1.5) for all species. Daytime bole CER often fell below temperature-based predictions, likely due to transpiration. The reduction (usually <10%) was less pronounced at the drier site. Twig CER showed more substantial (often >±50%) deviations from the predictions. Deviations were higher in the canopy than in the understory. Mean bole maintenance respiration (at 20°C and d=20 cm) was 0.66, 0.43 and 0.50 μMol m⁻¹, while the volume-based growth coefficient was around 5, 6 and 8 mol cm⁻³ for BC, RM and RO, respectively.
In a controlled study, BC and RM seedlings were fumigated in open-top chambers with sub-ambient, ambient and twice-ambient levels of ozone. The twice-ambient treatment reduced stem CER in BC by 50% (p=0.05) in July, but there was no treatment effect in September or in RM. Ozone reduced root/shoot ratio and diameter growth in BC, and Pmax in both species.Ph. D.
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Göttlicher, Sabine. "On the tree-root-soil-continuum - temporal and spatial coupling of the belowground carbon flux /." Umeå : Dept. of Forest Ecology and Management, Swedish University of Agricultural Sciences, 2007. http://epsilon.slu.se/200743.pdf.
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Nicoll, Bruce C. "The effects of soil, terrain and wind climate on tree root system development and anchorage." Thesis, University of Edinburgh, 2006. http://hdl.handle.net/1842/15525.
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Firstly, a database was constructed of tree anchorage measurements from almost 2000 trees of 12 conifer species. An analysis revealed that Sitka spruce had best anchorage on peat and poorest anchorage on gleyed mineral soils. Trees with root depths >80 cm had critical turning moments 10 to 15% larger than shallow rooted trees. There was better anchorage for grand fir and Douglas-fir than Sitka spruce with various soils and rooting depths. Lodgepole pine was less well anchored, as was shallow rooted (<40cm) Norway spruce on gleyed mineral soil and Corsican pine on medium depth (40-80cm) mineral soil. All other species had similar anchorage to Sitka spruce on equivalent soil. Secondly, as most tree pulling had been conducted on relatively horizontal sites, anchorage and root development of Sitka spruce was compared between a steep (30*) slope and an adjacent horizontal area with similar soil. No overall effect of terrain on anchorage was found, but trees pulled up-slope had significantly better anchorage than those pulled down-slope. Finally, the radial growth response of tree stems and structural roots to wind loading were examined in two experiments: 1. Growth ring chronologies from stems and structural roots of 46-year-old Sitka spruce trees grown on an exposed upland site, were compared with wind records. Wind speed was well correlated with growth of structural roots on the lee- and wind-ward side of the tree. 2. Wind movement, light and photosynthate supply were manipulated on 10-year-old Sitka spruce trees. Trees responded to reduced photosynthate supply (induced by branch girdling) with an immediate reduction in stem and root radial growth. Trees responded to a stand thinning treatment (increased light and wind movement), and to a thinning and guying treatment (increased light, reduced wind movement), with immediate increases in root radial growth, and increases in stem radial growth delayed by a year.
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Al, zalzaleh Hani Abdulkariem S. H. "Effects of root modification and container types on landscape trees." Thesis, University of Reading, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301913.
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Järnevi, Sara. "Lyckad trädflytt : Förberedande åtgärder och efterskötsels inverkan på trädets etablering efter flytt." Thesis, Högskolan i Gävle, Avdelningen för elektronik, matematik och naturvetenskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-23776.
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Syftet med denna rapport är att sammanställa fakta kring hur åtgärder före och efter trädflytt kan påverka trädets etablering. Rapporten behandlar även vilken inverkan rotbeskärning har på träd och hur nybildning av rötter kan främjas. Rapporten besvarar frågor kring hur ett träd reagerar på att bli flyttat och hur trädart, växtplats och tidigare åtgärder kan påverka resultatet av en trädflytt. Rapporten besvarar även frågor angående vilka åtgärder som kan genomföras, innan och efter trädflytt, för att förbättra trädets etablering på sin nya växtplats, vilken inverkan rotbeskärning har på det flyttade trädet och hur nybildning av finrötter kan främjas. Rapporten är skriven som en traditionell akademisk rapport och är baserad på litteratur som har samlats in från vetenskapliga artiklar, böcker och uppslagsverk. Vid trädflytt förlorar ett träd stora delar, cirka 90 procent, av sitt rotsystem och drabbas av stressymptom. Ett friväxande, sådd i naturen och icke-rotbeskuret, träd kan förlora ännu större delar av sitt rotsystem. Det är viktigt att undersöka om det är ett plantskoleträd eller ett friväxande träd och även vilken trädart som ska flyttas då det kan ha betydelse för hur lyckad trädflytten blir. Genom att utföra rotbeskärning skapas ett kompakt rotsystem som ger en minskad rotförlust. Rotbeskärning främjar även tillväxten av finrötter i rotklumpen, vilket gynnar trädet vid etablering och ger minskad vattenstress. Ofta genomförs en kronreducering för att reducera obalansen mellan krona och rötter. En måttlig kronreducering, mellan 10 och 30 procent, kan gynna trädet. Om trädet ska kunna etablera sig och överleva flytten måste det övervinna stressymptomen. Om ett träd ska kunna bilda nya rötter och ha tillväxt av grenar och skott behöver trädet ha god vitalitet. Bevattning spelar en essentiell roll för trädets överlevnad och etablering. Mulch kan ge god tillväxt av finrötter och bidra till en förbättrad etablering. Rapportens slutsats är att både förberedande åtgärder och efterskötsel har inverkan på trädets etablering och hur väl trädet klarar av att bli flyttat. En korrekt genomförd rotbeskärning bör utföras, en måttlig kronbeskärning av 10-30 procent av kronan bör utföras, träd ska flyttas under sin viloperiod och träd som flyttas bör ha hög vitalitet. Nybildning av rötter främjas av god markfukt, varm jord, jämn bevattning och att mulch läggs på.The purpose of this report was to put together facts regarding how the measures before and after tree transplanting can affect the establishment of the tree. The report also dealt with the impact that root pruning might have on trees and how regeneration of roots can be promoted. The report answers questions concerning how tree transplanting affects a tree and how tree species, locality and previous measures can influence the effect of a tree transplanting. The reports also answers a question concerning which measures could be performed, before and after tree transplanting, to improve the tree’s establishment in it’s new locality. The last question that this report answers is what impact root pruning has on the tree and how regeneration of fine roots can be favoured. The report is written as a traditional academic report and is based on literature that was collected from scientific articles, books and encyclopedias. A tree loses a large amount, approximately 90 percent, of its root system during the tree transplanting. This causes stress symptoms in the tree. A tree, sown and grown in nature, that has never been root pruned will lose even larger amounts of its root system when it’s transplanted. It’s important to do investigations before tree transplanting. Investigations should be done before tree transplanting to determine what kind of tree, nursery-grown or grown in nature, and what species is about to be transplanted. Both of these aspects may have an influence on how successful the transplanting is. Root pruning can make the root system more compact which reduces root loss during transplanting. Root pruning also increases the amount of fine roots in the root ball which is beneficent during establishment and also reduces water stress. The high amount of root loss causes an imbalance between crown and roots. The crown is often reduced to correct this imbalance and in this report it was proven that a moderate crown reduction is beneficial for the tree. The tree must overcome the stress symptoms to be able to survive and to establish itself. Trees need good vitality to be able to regenerate roots, shoots and branches. Irrigation plays an important part in the establishment and the survival of the tree. Mulch can promote regeneration of fine roots and contribute to an improved establishment. The conclusion of the report is that both preparatory measures and after care has an impact on the establishment and on how successful the transplanting of a tree will be. A correctly executed root pruning and a moderate crown pruning (10 to 30 percentage of the crown) should be carried out. Trees should be transplanted during their dormant season and trees, that are going to be transplanted, should have high vitality. Regeneration of roots is promoted by having good soil moisture, warm soil, even watering and applying mulch.