نتایج جستجو برای: distance from forest

تعداد نتایج: 5771037  

Journal: :Ecology letters 2018
Laurent Hébert-Dufresne Adam F A Pellegrini Uttam Bhat Sidney Redner Stephen W Pacala Andrew M Berdahl

In tropical regions, fires propagate readily in grasslands but typically consume only edges of forest patches. Thus, forest patches grow due to tree propagation and shrink by fires in surrounding grasslands. The interplay between these competing edge effects is unknown, but critical in determining the shape and stability of individual forest patches, as well the landscape-level spatial distribu...

Journal: :Journal of Graph Theory 2009
Pierre Hansen Alain Hertz Rim Kilani Odile Marcotte David Schindl

2016
Aurélie C. Shapiro Naikoa Aguilar-Amuchastegui Patrick Hostert Jean-François Bastin

BACKGROUND Recent studies have shown that fragmentation is an increasing threat to global forests, which has major impacts on biodiversity and the important ecosystem services provided by forested landscapes. Several tools have been developed to evaluate global patterns of fragmentation, which have potential applications for REDD+. We study how canopy height and above ground biomass (AGB) chang...

Journal: :محیط زیست طبیعی 0
زهرا نوری دانش آموختۀ دکتری جنگل داری، دانشکدۀ منابع طبیعی، دانشگاه تهران، ایران محمود زبیری استاد گروه جنگل داری و اقتصاد جنگل، دانشکدۀ منابع طبیعی، دانشگاه تهران، ایران جهانگیر فقهی دانشیار گروه جنگل داری و اقتصاد جنگل دانشکدۀ منابع طبیعی، دانشگاه تهران، ایران محمدرضا مروی مهاجر استاد گروه جنگل داری و اقتصاد جنگل، دانشکدۀ منابع طبیعی، دانشگاه تهران، ایران

beech forests in midland areas of hyrcanian forests of iran are the most important forests having the highest degree of naturalness. these forests are the valuable source of wood production and other forest products. one of the most important characteristics of plant communities is the spatial pattern of trees. ecological process in forest ecosystems are directly influenced by the spatial patte...

2003
Oili Kiikkilä

Heavy metals and sulphur have been emitted from the Cu-Ni smelter at Harjavalta since 1945. This article reviews the work that has been published in scientifi c journals after 1975 concerning heavy metal deposition and the effects of pollution on forest ecosystem around Harjavalta. The pollution has had diverse effects on boreal forest ecosystem, e.g. vegetation, nutrient cycle mediated by micr...

2014
Samantha Bailey Fabrice Requier Benoît Nusillard Stuart P M Roberts Simon G Potts Christophe Bouget

Wild pollinators have been shown to enhance the pollination of Brassica napus (oilseed rape) and thus increase its market value. Several studies have previously shown that pollination services are greater in crops adjoining forest patches or other seminatural habitats than in crops completely surrounded by other crops. In this study, we investigated the specific importance of forest edges in pr...

Journal: :Ecological applications : a publication of the Ecological Society of America 2006
Claire G Williams Shannon L LaDeau Ram Oren Gabriel G Katul

Predicting forest-tree seed dispersal across a landscape is useful for estimating gene flow from genetically engineered (GE) or transgenic trees. The question of biocontainment has yet to be resolved, although field-trial permits for transgenic forest trees are on the rise. Most current field trials in the United States occur in the Southeast where Pinus taeda L., an indigenous species, is the ...

Journal: :Remote Sensing 2018
Marie-Bé Leduc Anders Knudby

Wild leek, an endangered plant species of Eastern North America, grows on forest floors and greens up to approximately three weeks before the trees it is typically found under, temporarily allowing it to be observed through the canopy by remote sensing instruments. This paper explores the accuracy with which wild leek can be mapped with a low-flying UAV. Nadir video imagery was obtained using a...

2015
Olga Heim Julia T. Treitler Marco Tschapka Mirjam Knörnschild Kirsten Jung Danilo Russo

Landscape heterogeneity is regarded as a key factor for maintaining biodiversity and ecosystem function in production landscapes. We investigated whether grassland sites at close vicinity to forested areas are more frequently used by bats. Considering that bats are important consumers of herbivorous insects, including agricultural pest, this is important for sustainable land management. Bat act...

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