نتایج جستجو برای: forest range

تعداد نتایج: 766089  

Objective: Ecosystems with mixed species compared to the ones with pure compositions provide a broader range of options in the fields of biodiversity, conservation, protection and restoration. Nearly all forest plantations are established as monocultures, but research has shown that there are potential advantages to be gained by using carefully designed species mixtures in place of monocultures...

2012
Author Perry J. Williams R. J. Gutiérrez Sheila A. Whitmore PERRY J. WILLIAMS

We studied home range and habitat selection of radio-marked adult California spotted owls (Strix occidentalis occidentalis) randomly selected from among the breeding population of owls in the central Sierra Nevada, California from June to October 2006. The most parsimonious home-range estimate for our data was 555 ha (SE 1⁄4 100 ha). Home-range size was positively correlated with the number of ...

2004
Phil Townsend Jane Foster

The objectives of this investigation were to evaluate the EO-1 Hyperion hyperspectral sensor for mapping forest composition and structure in rugged terrain and to compare its performance with that of AVIRIS and the Landsat 7 Enhanced Thematic Mapper Plus (ETM+). The study focused on species composition mapping with Hyperion, AVIRIS, and Landsat using a study site in the Green Ridge State Forest...

2008
Guillermo A. Mendoza Jerome K. Vanclay Jerry Vanclay

Different types of models have been developed and applied to address various problems and issues in forestry. This paper reviews modelling trends in four areas, namely, forest management planning and decision-making, forest dynamics and growth projection, forest landscape and spatial models and participatory forest management models. The first type includes decision models generally structured ...

2012
Marion Pfeifer Neil D. Burgess Ruth D. Swetnam Philip J. Platts Simon Willcock Robert Marchant

In East Africa, human population growth and demands for natural resources cause forest loss contributing to increased carbon emissions and reduced biodiversity. Protected Areas (PAs) are intended to conserve habitats and species. Variability in PA effectiveness and 'leakage' (here defined as displacement of deforestation) may lead to different trends in forest loss within, and adjacent to, exis...

Journal: :محیط شناسی 0
علی جعفری استادیار گروه علوم جنگل دانشکدۀ منابع طبیعی دانشگاه شهرکرد زهرا آرمان دانشجوی کارشناسی ارشد جنگل داری، دانشکدۀ منابع طبیعی و علوم زمین، دانشگاه شهرکرد علی سلطانی استادیار گروه علوم جنگل، دانشکدۀ منابع طبیعی و علوم زمین، دانشگاه شهرکرد علی لطفی هیات علمی دانشگاه صنعتی اصفهان

introduction forest ecosystems have continuously downgraded due to every environmental pressure including climate change, aerosols deposits, industrial pollutions and other degradation factors. the output soon or late would be a different forest. forest monitoring is a well-regulated and usually long running procedure, which has the ability to detect these phenomena and reactions based on aims ...

2013
James D. Wickham Timothy G. Wade Kurt H. Riitters

Methods Ordinary least squares regression was used to develop relationships between forest extent and surface temperature. Forest extent was derived from the 900 m 2001 National Land Cover Database (NLCD 2001) and surface temperature data were from the MODIS 1 km 8-day composite (MYD11A2). Forest–surface temperature relationships were developed for winter, spring, summer, autumn and annually us...

2005
V. S. Solovyev V. I. Kozlov

The spatial-temporal dynamics of forest fires for last five years in latitudinal range 40-74 degrees of the northern latitude are analyzed with using the data of the radiometer AVHRR/NOAA. It was shown that forest fires are observed from May till September, basically during three summer months with a maximum of the activity during the second half of summer. On a phase of a maximum of an 11-year...

Journal: :جنگل و فرآورده های چوب 0
آزاده دلجویی کارشناس ارشد مهندسی جنگل دانشکدة منابع طبیعی دانشگاه تهران، کرج، ایران احسان عبدی دانشیار گروه جنگلداری و اقتصاد جنگل دانشکدة منابع طبیعی دانشگاه تهران، کرج، ایران باریس مجنونیان استاد گروه جنگلداری و اقتصاد جنگل دانشکدة منابع طبیعی دانشگاه تهران، کرج، ایران

forest roads are directions in natural habitats that used to transport wood products, secondary forest products and recreation. constructing forest roads causes trees clearing with specified width thus lead to direct or indirect changes in forest ecosystems and forest environment. this study aims to assess the changes of diversity and richness indices in main and secondary forest roads in a par...

1997
Peter B. Woodbury James E. Smith John A. Laurence

Most models of the potential effects of climate change on forest growth have produced deterministic predictions. However, there are large uncertainties in data on regional forest condition, estimates of future climate, and quantitative relationships between environmental conditions and forest growth rate. We constructed a new model to analyze these uncertainties along with available experimenta...

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