نتایج جستجو برای: forest species changing

تعداد نتایج: 771031  

Journal: :جنگل و فرآورده های چوب 0
بیت الله محمودی استادیار گروه جنگلداری دانشکدة منابع طبیعی و علوم زمین دانشگاه شهرکرد، شهرکرد، ایران احمد بازگیر دانشجوی دکتری جنگلداری دانشکدة کشاورزی دانشگاه لرستان، خرم آباد، ایران جهانگیر فقهی دانشیار گروه جنگلداری و اقتصاد جنگل دانشکدة منابع طبیعی دانشگاه تهران، کرج، ایران فاطمه جعفری کارشناس ارشد مدیریت کشاورزی دانشکدة منابع طبیعی دانشگاه تهران، کرج، ایران

one of the indicators of management and sustainability control of forest resources is the definition deforestation and degradation types. these factors hazard quantitative and qualitative of the iranian forests. in this study with integrated approach, different forms of forest degradation identified in the forest areas with a reviews of library resources and then investigation the degree of sta...

2017
Jasmine K. Janes Jill A. Hamilton

Forest tree hybrid zones provide a wealth of novel genetic variation that can be harnessed to safeguard populations in changing climates. In the past 30 years, natural and artificial forest hybrid zones have facilitated significant contributions to selective breeding programs, conservation, and our understanding of the evolutionary processes and mechanisms that influence the maintenance of spec...

Journal: :ecopersia 2015
yahya kooch fatemeh rostayee seyed mohsen hosseini

the present study aimed to assess pure planted species (i.e., alnus subcordata l., poplus deltoids l., taxadium distichum l. rich) and a mixed natural forest (i.e., dominated by quercus castaneifolia c. a. mey. - carpinus betulus l. - parrotia persica c. a. meyer) on basis of some soil quality indices in mazandaran province, northern iran. sixteen samples per stand were taken from the top 10 cm...

2014
Fabián B Gálvez Andrew T Hudak John C Byrne Nicholas L Crookston Robert F Keefe

BACKGROUND Forest resources supply a wide range of environmental services like mitigation of increasing levels of atmospheric carbon dioxide (CO2). As climate is changing, forest managers have added pressure to obtain forest resources by following stand management alternatives that are biologically sustainable and economically profitable. The goal of this study is to project the effect of typic...

Trees are the most important biological elements of forest ecosystems. The variability of the tree species composition inhabiting in the Oriental beech forest, not only forms different forest types but also has a remarkable impact on the species diversity of forest floor plants, due to the existence of trees in the overstory layer. In this research, forest types of an an Oriental beech were ide...

2013
Xiaona Li Hong S. He Zhiwei Wu Yu Liang Jeffrey E. Schneiderman

Forest management under a changing climate requires assessing the effects of climate warming and disturbance on the composition, age structure, and spatial patterns of tree species. We investigated these effects on a boreal forest in northeastern China using a factorial experimental design and simulation modeling. We used a spatially explicit forest landscape model (LANDIS) to evaluate the effe...

Economically optimal management of a continuous cover forest is considered here. Initially, there is a large number of trees of different sizes and the forest may contain several species. We want to optimize the harvest decisions over time, using continuous cover forestry, which is denoted by CCF. We maximize our objective function, the expected present value, with consideration of stochastic p...

TThe forest plantation strategy is to do with the identification of the most appropriate zones and the areas that are most suitable for different species. However, the success of this strategy requires the precise determination of the species ecological demands and the evaluation of the land before the establishment of the plantation. The purpose of this study is to assess the ecological capabi...

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