نتایج جستجو برای: distance from forest

تعداد نتایج: 5771037  

2003
Arthur Groot Sylvie Gauthier Yves Bergeron

The objective of this paper is to discuss approaches and issues related to modelling stand dynamics for multi-cohort forest management in eastern Canadian boreal forests. In these forests, the interval between wildfires can be rather long, and the development of natural forest stands may include the establishment, growth and mortality of several cohorts of trees. Later cohorts are characterised...

Journal: :Genetics and molecular research : GMR 2017
A B Baldoni L H O Wadt T Campos V S Silva V C R Azevedo L R Mata A A Botin N O Mendes F D Tardin H Tonini E S S Hoogerheide A M Sebbenn

Due to the nutritional content and commercial value of its seeds, Bertholletia excelsa is one of the most important species exploited in the Amazon region. The species is hermaphroditic, insect pollinated, and its seeds are dispersed by barochory and animals. Because the fruit set is dependent on natural pollinator activity, gene flow plays a key role in fruit production. However, to date, ther...

Journal: :جنگل و فرآورده های چوب 0
فریده امیدوار حسینی دانشجوی کارشناسی ارشد رشتۀ جنگلداری، دانشگاه آزاد اسلامی، واحد علوم و تحقیقات تهران، تهران، ایران رضا اخوان استادیار پژوهش، مؤسسۀ تحقیقات جنگل ها و مراتع کشور، تهران، ایران هادی کیادلیری استادیار گروه جنگلداری، دانشگاه آزاد اسلامی، واحد علوم و تحقیقات، تهران، ایران اسداله متاجی دانشیار گروه جنگلداری، دانشگاه آزاد اسلامی، واحد علوم و تحقیقات، تهران، ایران

one of the most visible aspects of a forest stand structure is the spatial patterns of trees. competition affects on forest structure and its understanding is important, when the purpose of forest management is to imitate the dynamic of natural ecosystems. for this purpose, an unmanaged intact forest was selected with 26 hectares area. all chestnut leaf oak (quercus castaneifolia) trees with a ...

2005
Lucina Hernández John W. Laundré Johan T. du Toit

In 1995, wolves Canis lupus were reintroduced into Yellowstone National Park, USA, where they began to prey on ungulate species. In response to this new predation risk by wolves, we predicted that the two main ungulate species, elk Cervus elaphus and bison Bison bison, should compensate by reducing their use of riskier open meadows and increasing their use of safer forest. Additionally we predi...

Journal: :محیط زیست طبیعی 0
حسین وارسته مرادی استادیار گروه محیط زیست، دانشکده شیلات و محیط زیست، دانشگاه علوم کشاورزی و منابع طبیعی گرگان، ایران

population management of exploited species requires information on absolute density and abundance through reliable survey methods. the baseline information is further needed for population dynamics studies and determination of conservation status. the current population size of pheasant is totally unknown, because there is no official attempt to estimate population size in previous years. in th...

2014
Miguel A. Munguía-Rosas Salvador Montiel

Studies of the effects of patch size and isolation on plant species density have yielded contrasting results. However, much of the available evidence comes from relatively recent anthropogenic forest fragments which have not reached equilibrium between extinction and immigration. This is a critical issue because the theory clearly states that only when equilibrium has been reached can the numbe...

Journal: :Annals of botany 2007
I M Andrade S J Mayo C van den Berg M F Fay M Chester C Lexer D Kirkup

BACKGROUND AND AIMS This study sought genetic evidence of long-term isolation in populations of Monstera adansonii var. klotzschiana (Araceae), a herbaceous, probably outbreeding, humid forest hemi-epiphyte, in the brejo forests of Ceará (north-east Brazil), and clarification of their relationships with populations in Amazonia and the Atlantic forest of Brazil. METHODS Within-population genet...

Journal: :international journal of environmental research 2010
j. lepetu j. alavalapati p.k. nair

conservation of biodiversity in protected areas will be more challenging if local communities are heavily dependent on them for various products and subsistence needs. this study estimated forest dependency and identified factors influencing dependency for households living around kasane forest reserve (kfr). data collected from 237 households were analyzed using logistic regression model. logi...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید