background: this study investigated the effects of some important meteorological parameters and filler type compounds on phytotoxicity of captan in peach trees in the north of iran. captan is a phthalimide fungicide which has frequently been used in northern regions of iran to control certain plant diseases. this fungicide has caused intense phytotoxicity in peach trees which was first observed...

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 ...

Bénédicte Haas, University of Paris-Dauphine, France Limits of Non-increasing Markov Chains and Applications to Random Trees and Coalescents Consider a non-increasing Markov chain with values in the set of non-negative integers, starting from a large integer !. We describe its scaling limit as ! → ∞, under the assumption that the large jump events are rare and happen at rates that behave like a...

A purpose of Zagros forests preservation plan is to reduce degradation factors through empowering woodman beneficiaries and underdevelopment of rural forested areas which appear as scattered agronomies inside and in forest margins, trees cutting for power supply, trees cutting for hay supply or making coal in forested regions. Therefore, natural resources experts believe that, by creation or im...

---~Y(z) = ~(Y(z)), which is non linear and autonomous. Singularity analysis applied to the intervening generating functions then permits to analyze asymptotically a number of parameters of the trees, like: root degree, number of leaves, path length, and level of nodes. In this way it is found that various models share common features: path length is O(n log n), the distribution of node levels ...

Numerous simulation studies have investigated the accuracy of phylogenetic inference of gene trees under maximum parsimony, maximum likelihood, and Bayesian techniques. The relative accuracy of species tree inference methods under simulation has received less study. The number of analytical techniques available for inferring species trees is increasing rapidly, and in this paper, we compare the...

Forest ecosystems where periodical tree bark harvesting is a major economic activity may be particularly vulnerable to disturbances such as fire, since debarking usually reduces tree vigour and protection against external agents. In this paper we asked how cork oak Quercus suber trees respond after wildfires and, in particular, how bark harvesting affects post-fire tree survival and resprouting...

Large old trees are critically important keystone structures in forest ecosystems globally. Populations of these trees are also in rapid decline in many forest ecosystems, making it important to quantify the factors that influence their dynamics at different spatial scales. Large old trees often occur in forest landscapes also subject to fire and logging. However, the effects on the risk of col...