نتایج جستجو برای: forest trees

تعداد نتایج: 184211  

Journal: :Tree physiology 1996
Peter Becker

Daytime xylem sap flow was measured by the compensation heat pulse velocity technique in dipterocarp forest trees growing on sandy loam (haplic acrisol) and in heath forest trees growing on bleached sand (albic arenosol) in Brunei during wet and dry periods. In dipterocarp forest trees, daily sap flow was stable during the dry period but declined on rainy days presumably as a result of reduced ...

2008
Hung-Lung Wang

In this paper, we consider the problem of maintaining the centdians in a fully dynamic forest. A centdian is a location in the given network which minimizes a convex combination of the longest distance and the sum of distances from all clients to it. A fully dynamic forest is a forest, i.e., a set of trees, in which the following operations are allowed: to insert an edge between different trees...

Knowledge about the relationship between tree height (H) and diameter at breast height (D) is crucial for forest planning, monitoring, biomass estimation, and forest stands dynamics description. In this study, 20 different height-diameter models were evaluated to estimate accurately the height of the trees of Pinus brutia and Cupressus sempervirens var. horizontalis species in Arabdagh region (...

A. Salehi, al. et

The purpose of this study was to investigate the impacts of forest-based activities on the conditions of the Ganaveh woodland in the southern Zagros, Iran, and to suggest strategies for improving the implementation of forest resource management plans. Woodland inventory data was gathered in 2003, accompanied with data from interviews in 2008, were used in this study. The results show that there...

2016
Steven T. Brantley Morgan L. Schulte Paul V. Bolstad Chelcy F. Miniat

Small trees and shrubs play an important role in forest diversity and regeneration and may contribute substantially to ecosystem fluxes of carbon and water; however, relatively little attention is given to quantifying the contribution of small trees to forest processes. One reason for this may be that the allometric equations developed for large trees tend to systematically underestimate struct...

2015
Kiomars Sefidi

Dead wood and habitat tree such as fallen logs, snags, stumps and cracks and loos bark etc. are regarded as an important ecological component of forests on which many forest dwelling species depend on presence of them within forest ecosystems. Meanwhile its relation to management history in Caspian forest has gone unreported. The aim of research was to compare the amounts of dead wood and habit...

Journal: :محیط زیست طبیعی 0
وحید علی جانی دانشجوی کارشناسی ارشد گروه جنگلداری و اقتصاد جنگل دانشکده منابع طبیعی دانشگاه تهران، ایران جهانگیر فقهی دانشیار گروه جنگلداری و اقتصاد جنگل دانشکده منابع طبیعی دانشگاه تهران، ایران محمود زبیری استاد گروه جنگلداری و اقتصاد جنگل دانشکده منابع طبیعی دانشگاه تهران، ایران محمدرضا مروی مهاجر استاد گروه جنگلداری و اقتصاد جنگل دانشکده منابع طبیعی دانشگاه تهران، ایران

quantifying spatial structure is one of the most important components, describing natural ecosystems and their biodiversity. in this study, a set of indices and functions related to spatial structure using 102 established plots with an area of 1000 m2 were presented. to achieve spatial structure of carpinus-fagus type, a set of indices (clark & evans, uniform angle, shannon-wiener, mingling and...

Journal: :Ecology 2013
Joseph W Veldman W Brett Mattingly Lars A Brudvig

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 eq...

Old trees as the most important genetic reserves of the country have great importance and value in various aspects of ecology, forest restoration management, ecotourism and even history. In this research, after identification of the old trees in the forests of Ilam province, their morphological characteristics including DBH, trunk height, total height, crown length, min & max crown diameter, cr...

2008
Thanawat Thongtan Somjit Arch-Int

1 Graduate Student, Information Technology, Department of Computer Science, Faculty of Science, Khon Kaen University, Thailand 2 Assistant Professor, Computer Science, Department of Computer Science, Faculty of Science, Khon Kaen University, Thailand * corresponding author, e-mail: [email protected] Abstract Community forests are essential to the local population of Thailand. The problem is that...

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