نتایج جستجو برای: for five trees
تعداد نتایج: 10468587 فیلتر نتایج به سال:
The present investigation was aimed to study the qualitative and quantitative characteristics of Lebanon Oak (Quercus libani Olive.) in Marivan city-kordistan. To investigate the effect of altitude on the qualitative and quantitative characteristics of Lebanon Oak, 108 circular plots of 1000 m2 on three elevation classes of 1400-1600, 1600-1800 and 1800-2000 m were designated. Within each plot,...
Awareness of quality and quantity of wood produced in forestry plans play an important role in management of this product in market. The objective of this study that has been carried out in 7th watershed of north forest of Iran was to determine effective factors on wood breakage in felled trees, compare wood losses during felling and identify wood losses in felled trees and methods of their pre...
In recent years, oak trees in the Zagros forests have suffered a lot of fatalities for unclear reasons. Determining the rate and severity of forest crown density changes is important for the investigation and management of these forests. This research was carried out with the aim of determining the amount of crown cover changes in the forest area of Dashtebarm in Fars province under the influen...
in this paper, using generalized {polya} urn models we find the expected value of the size of a branch in recursive $k$-ary trees. we also find the expectation of the number of nodes of a given outdegree in a branch of such trees.
diameter is such a notable characteristic in forest inventory that it is important to have a suitablemethod of its measurement, especially in coppice trees. this seems more important in zagros foreststhat most of them are covered with coppice trees. so this research was aimed to find an efficientmethod in studying the diameter at root collar (drc) of persian oak coppice trees as the mostimporta...
This paper reviews P´olya urn models and their connection to random trees. Basic results are presented, together with proofs that underly the historical evolution of the accompanying thought process. Extensions and generalizations are given according to chronology: • P´olya-Eggenberger’s urn • Bernard Friedman’s urn • Generalized P´olya urns • Extended urn schemes • Invertible urn schemes ...
The non-destructive Meyer method was evaluated to determine the bark volume of beech (Fagus orientalis Lipsky) stands in north of Iran. The sample size was 185 standing trees collected from 4 geographical aspects (north, south, west and east) aspects. The constant k values and bark thickness (2e mm) of 185 standing trees were used to calculate the bark volume by the Meyer method. In this study,...
Vegetation due to its root system by creating cohesion of soil particles, significantly affects hill slope mechanical properties related to shallow landslides and slope stability. In this regard, the root engineering characteristics of forest species are important. The aim of this study was to investigate the distribution pattern of persian oak and hawthorn in Zagross forests. For this purpose,...
Background: Response variables in most medical and health-related research have an ordinal nature. Conventional modeling methods assume predictor variables to be independent, and consider a large number of samples (n) compared to the number of covariates (p). Therefore, it is not possible to use conventional models for high dimensional genetic data in which p > n. The present study compared th...
Let $G$ be a finite and simple graph with edge set $E(G)$. The second geometric-arithmetic index is defined as $GA_2(G)=sum_{uvin E(G)}frac{2sqrt{n_un_v}}{n_u+n_v}$, where $n_u$ denotes the number of vertices in $G$ lying closer to $u$ than to $v$. In this paper we find a sharp upper bound for $GA_2(T)$, where $T$ is tree, in terms of the order and maximum degree o...
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