نتایج جستجو برای: tree density northern zagros forest
تعداد نتایج: 762413 فیلتر نتایج به سال:
Mapping of forest extent is a prerequisite to acquire quantitative and qualitative information about forests and to formulate management and conservation strategies. forest canopy density (FCD) model is one of the useful RS methods for forest mapping using satellite images. One of the most serious challenges in FCD model is the weakness in the calculation of canopy density in low density forest...
bending and compression strength of paulownia fortunie wood grown in educational and research forest located at shastkalate, gorgan were studied. paulownia trees were selected among five years old plantation. sampling spot was conducted following standard procedure. trees were cut into logs, which were then cut into 6 cm thickness wood blocks based on geographic directions. wood blocks were div...
Unprecedented rates of climate warming over the past century have resulted in increased forest stress and mortality worldwide. Decreased tree growth in association with increasing temperatures is generally accepted as a signal of temperature-induced drought stress. However, variations in tree growth alone do not reveal the physiological mechanisms behind recent changes in tree growth. Examining...
Assessment of forest structure and their spatial patterns are essential for managing and evaluation of forest ecosystems. This study was conducted at the Zagros forests in Kermanshah to evaluate the forest structural characteristics and their spatial distribution. Data was collected from 25 plots (400 m2) in a 100 m × 100 m systematic sampling grid. The spacing between plots was 50 m. In each p...
The optimum road spacing has been studied by many researches. It is an important step of forest road network planning. The goals of this study are determining the optimum road spacing in Kheiroudkenar forest of Nowshahr in Northern Iran and study of effect of kind of skidder on skidding cost and road spacing. Continues time study method was used to determine the production rate of TAF and Timbe...
plant diversityis essential to maintain the health of planet's ecosystems. conservation of biodiversity is necessary for the ecological stability and productivity in natural ecosystems. the aim of this research was to study the biodiversity and richness of plant species (including trees, shrubs and grasses) related to the environmental factors (soil and physiography) in the forests of zagros, w...
Protected areas (PAs) on tropical mountains undergo greater forest destruction in their lower altitudes. We compared the extent of forested, nonforested, and fragmented areas between lowland (o 1000 m asl) and montane zones of the Blue Mountains inside the Blue and John Crow Mountains National Park established in Jamaica in 1993. We found that in 2008, inside the montane zone, only 4 percent of...
the optimum road spacing has been studied by many researches. it is an important step of forest road network planning. the goals of this study are determining the optimum road spacing in kheiroudkenar forest of nowshahr in northern iran and study of effect of kind of skidder on skidding cost and road spacing. continues time study method was used to determine the production rate of taf and timbe...
Aim To detect possible expansion of boreal forest stands in response to recent warming. Previous modelling studies have concluded that major shifts in vegetation patterns, including changes in boreal forest extent, could arise during the next two centuries under global warming scenarios. However, ®eld investigations of tree stands at ecotones have so far revealed little indication of stand resp...
forest types mapping, is one of the most necessary elements in the forest management and silviculture treatments. traditional methods such as field surveys are almost time-consuming and cost-intensive. improvements in remote sensing data sources and classification –estimation methods are preparing new opportunities for obtaining more accurate forest biophysical attributes maps. this research co...
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