نتایج جستجو برای: height of trees

تعداد نتایج: 21175163  

Journal: :Annals of botany 2006
Koichi Takahashi Agus Rustandi

BACKGROUND AND AIMS Growth in trunk height in canopy openings is important for saplings. How saplings increase height growth in canopy openings may relate to crown architectural constraints. Responses of crown development to canopy openings in relation to trunk height growth were studied for saplings (0.2-2.5 m tall) of eight tropical submontane forest tree species in Indonesia. The results of ...

Journal: :جنگل و فرآورده های چوب 0
فاطمه رنجبر دانشجوی کارشناسی ارشد دانشکده منابع طبیعی دانشگاه گیلان کامبیز طاهری آبکنار دانشیار دانشکده منابع طبیعی دانشگاه گیلان کیومرث سفیدی استادیار دانشکده فناوری کشاورزی و منابع طبیعی دانشگاه محقق اردبیلی علی امیدی کارشناس ارشد اداره کل منابع طبیعی و آبخیزداری استان گیلان

the establishment and survival of seedlings is one of the main objectives of forest management which ensures continues production. the aim of this article is the investigation of dead trees effect on beech and hornbeam seedlings in masal's forests. for this reason, 30 dead trees were selected, and the control trees were selected in four aspects around the dead trees. they were the same as ...

Journal: :جنگل و فرآورده های چوب 0
سهیل سهیلی اصفهانی کارشناس ارشد مهندسی منابع طبیعی، گرایش جنگل داری، دانشکدۀ منابع طبیعی ساری، ساری، ‏ایران اصغر فلاح دانشیار گروه جنگل داری، دانشگاه علوم کشاورزی و منابع طبیعی ساری، ساری، ایران

in order to study the qualitative, quantitative characteristics of a pure common populus alba stand in polkalleh & a mixed stand of populus alba & populus nigra in karchegan, two 30-year-old stands were selected with a plantation interval ( spacing) of 2.5 × 1.5 m in each of which 30 pcs of 2 are samples were randomly selected. in each sample pc all the trees diameters were measured using a dia...

Journal: :جنگل و فرآورده های چوب 0
مهدی کاکاوند دانشجوی کارشناسی ارشد، دانشکدة منابع طبیعی، دانشگاه تهران، کرج، ایران محمدرضا مروی مهاجر استاد گروه جنگل داری و اقتصاد جنگل دانشکدة منابع طبیعی، دانشگاه تهران، کرج، ایران خسرو ثاقب طالبی دانشیار پژوهش، مؤسسة تحقیقات جنگل ها و مراتع کشور، تهران، ایران کیومرث سفیدی استادیار، دانشگاه محقق اردبیلی، دانشکدة منابع طبیعی، اردبیل، ایران

this study was designed to investigate the structural characteristics of beech forests in the middle stage of ecological succession. in order to this purpose undisturbed beech stands in kheyroud forest had chosen and three one hectare sampling plot laid out. all of tree species measured with full callipering method and diameter and height of trees were recorded. natural regeneration within one ...

2008
Nicolas Broutin Philippe Flajolet

This extended abstract is dedicated to the analysis of the height of non-plane unlabelled rooted binary trees. The height of such a tree chosen uniformly among those of size n is proved to have a limiting theta distribution, both in a central and local sense. Moderate as well as large deviations estimates are also derived. The proofs rely on the analysis (in the complex plane) of generating fun...

2011
T. R. Feldpausch L. Banin O. L. Phillips T. R. Baker S. L. Lewis C. A. Quesada K. Affum-Baffoe E. J. M. M. Arets N. J. Berry M. Bird E. S. Brondizio P. de Camargo J. Chave G. Djagbletey T. F. Domingues M. Drescher P. M. Fearnside M. B. França N. M. Fyllas G. Lopez-Gonzalez A. Hladik N. Higuchi M. O. Hunter Y. Iida K. A. Salim A. R. Kassim M. Keller J. Kemp D. A. King J. C. Lovett B. S. Marimon B. H. Marimon-Junior E. Lenza A. R. Marshall D. J. Metcalfe E. T. A. Mitchard E. F. Moran B. W. Nelson R. Nilus E. M. Nogueira

Tropical tree height-diameter (H:D) relationships may vary by forest type and region making large-scale estimates of above-ground biomass subject to bias if they ignore these differences in stem allometry. We have therefore developed a new global tropical forest database consisting of 39 955 concurrent H and D measurements encompassing 283 sites in 22 tropical countries. Utilising this database...

رضایی , حمیدرضا, وارسته مرادی , حسین , پارسایی, فاطمه,

The species composition of a bird community is dependent upon many factors. Within any geographic area, vegetation structure may be the most important factor. The changes of bird community composition based on foraging behavior in relation to 3 different harvesting systems, including strip cutting, group selection logging, and single tree selection logging, was evaluated in a virgin area in thi...

2015
C. HEUBERGER H. PRODINGER S. WAGNER

Multi-edge trees as introduced in a recent paper of Dziemiańczuk are plane trees where multiple edges are allowed. We first show that d-ary multi-edge trees where the out-degrees are bounded by d are in bijection with classical d-ary trees. This allows us to analyse parameters such as the height. The main part of this paper is concerned with multi-edge trees counted by their number of edges. Th...

Journal: :Journal of theoretical biology 2016
Farah Ben-Naoum Christophe Godin

By nature, tree structures frequently present similarities between their sub-parts. Making use of this redundancy, different types of tree compression techniques have been designed in the literature to reduce the complexity of tree structures. A popular and efficient way to compress a tree consists of merging its isomorphic subtrees, which produces a directed acyclic graph (DAG) equivalent to t...

2009

Question: Does the proximity of shrubs affect seasonal water stress of young Austrocedrus chilensis trees (a native conifer of the Austral Temperate Forest of South America) in xeric sites? Location: A. chilensis xeric forest in northwest Patagonia, Argentina. Methods: We examined the dependence of predawn twig water potential on tree development (seedling to adult) and proximity to nurse shrub...

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