نتایج جستجو برای: forest density

تعداد نتایج: 509797  

2016
Paul D. Pickell Nicholas C. Coops Sarah E. Gergel David W. Andison Peter L. Marshall

Understanding the development of landscape patterns over broad spatial and temporal scales is a major contribution to ecological sciences and is a critical area of research for forested land management. Boreal forests represent an excellent case study for such research because these forests have undergone significant changes over recent decades. We analyzed the temporal trends of four widely-us...

Journal: Desert 2006
M. Baghestani Maybodi N. Baghestani Maybodi, S. Soufizadeh

The high quality and quantity seed production in old saxual shrubs are essential for regeneration and sustainable development of saxual forests in desert areas. The objective of this study was to determine the effects of different pruning height on saxual seed production. The study was carried out in an obviously wilted saxual forest located in Ashkezar desert in Yazd in 1994. The experiment wa...

2007
Cynthia M. Roberts Richard P. Duncan Kerry-Jayne Wilson

The forests of Rangatira Island (218 ha) in the Chatham Islands are a critical breeding site for a number of rare and threatened forest bird species, but are also home to more than three million seabirds, which could significantly affect forest regeneration processes. We surveyed the forests of Rangatira Island by establishing 40 permanent forest plots, estimated seabird density through burrow ...

2004
Anne W. Nolin

Vegetation structure and density affect the dynamics of snow accumulation and ablation. Vegetation also affects our ability to estimate snow-covered area accurately from satellite-based sensors. The objective of this case study is to demonstrate how the angular pattern of reflectance from vegetation over snow can provide information on forest cover density. Imagery from the Multi-angle Imaging ...

Journal: :Remote Sensing 2012
Paul M. Treitz Kevin Lim Murray Woods Doug Pitt Dave Nesbitt Dave Etheridge

Over the past two decades there has been an abundance of research demonstrating the utility of airborne light detection and ranging (LiDAR) for predicting forest biophysical/inventory variables at the plot and stand levels. However, to date there has been little effort to develop a set of protocols for data acquisition and processing that would move governments or the forest industry towards co...

2001
M. Saei

The increasing use of satellite Remote Sensing for civilian use has proved to be the most cost effective means of mapping and monitoring environmental changes in terms of vegetation and non-renewable resources, especially in developing countries. Data can be obtained as frequently as required to provide information for determination of quantitative and qualitative changes in terrain. Forests as...

2015
Yanqiu Hu Zhiyao Su Wenbin Li Jingpeng Li Xiandong Ke Ting Wang

We assessed the impact of species composition and stand structure on the spatial variation of forest carbon density using data collected from a 4-ha plot in a subtropical forest in southern China. We found that 1) forest biomass carbon density significantly differed among communities, reflecting a significant effect of community structure and species composition on carbon accumulation; 2) soil ...

1980
W. Veatch P. D. Brooks J. R. Gustafson N. P. Molotch

Although many studies have investigated the effects of forest cover on streamflow and runoff, and several have examined the effects of canopy density on snowpack accumulation, the impacts of forest canopy density on spatial patterns of snowmelt input to catchments remain relatively underquantified. We performed an intensive snow depth and density survey during maximum accumulation in a mid-lati...

Journal: :جنگل و فرآورده های چوب 0
عفت رضایی دانشجوی کارشناسی ارشد جنگل داری، دانشگاه آزاد اسلامی، واحد علوم و تحقیقات تهران، تهران، ایران رضا اخوان استادیار پژوهش، بخش تحقیقات جنگل، مؤسسۀ تحقیقات جنگل ها و مراتع کشور، تهران، ایران جواد سوسنی استادیار، دانشکدۀ کشاورزی، دانشگاه لرستان، خرم آباد، ایران مهدی پورهاشمی استادیار پژوهش، بخش تحقیقات جنگل، مؤسسۀ تحقیقات جنگل ها و مراتع کشور، تهران، ایران

estimation and mapping of forest resources is a precondition for management, planning and research.this research was conducted to investigate the spatial structure and estimation of crown cover anddensity of an oak forest in the west of iran (loristan province) using kriging interpolation method ofgeostatistics. field sampling was performed based on a 100 m×100 m systematic grid using 2000 m2ci...

Journal: :تحقیقات جنگل و صنوبر ایران 0
عیسی انیسی کارشناس ارشد جنگل داری، دانشگاه آزاد اسلامی، واحد علوم و تحقیقات تهران هادی کیادلیری استادیار، دانشگاه آزاد اسلامی، واحد علوم و تحقیقات تهران رضا اخوان استادیار پژوهش، موسسه تحقیقات جنگلها و مراتع کشور ساسان بابایی کفاکی استادیار، دانشگاه آزاد اسلامی، واحد علوم و تحقیقات تهران

this study was performed in order to consider the effect of management plans on forest, through comparison between qualitative and quantitative characteristics of managed and unmanaged forests. compartment no. 149 from shourab district (52.8 ha) and compartment no. 218 from jamand district (68.7 ha) were selected as managed and unmanaged forests, respectively and were inventoried using a system...

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