نتایج جستجو برای: canopy cover

تعداد نتایج: 122030  

2006
LUIS SCHIESARI

1. The gradient in pond canopy cover strongly influences freshwater species distributions. This study tested the effects of canopy cover on the performance of two species of larval anurans, a canopy cover generalist (Rana sylvatica, the wood frog) and an open-canopy specialist (R. pipiens, the leopard frog), and tested which factors co-varying with canopy cover mediate these effects. 2. A field...

Journal: :Remote Sensing 2016
Paul Mannix Montesano Christopher S. R. Neigh Joseph O. Sexton Min Feng Saurabh Channan K. Jon Ranson John R. Townshend

Monitoring current forest characteristics in the taiga ́tundra ecotone (TTE) at multiple scales is critical for understanding its vulnerability to structural changes. A 30 m spatial resolution Landsat-based tree canopy cover map has been calibrated and validated in the TTE with reference tree cover data from airborne LiDAR and high resolution spaceborne images across the full range of boreal for...

2007
Chris B. Zou Greg A. Barron-Gafford David D. Breshears

[1] The emerging interdisciplinary approaches of ecohydrology and hydropedology are sensitive to variation in soil-surface energy inputs, which are primarily modified by topography and woody plant canopies. Yet a synthesis of the interactive effects of these two modification types is lacking. We systematically estimated near-ground surface solar radiation inputs as modified by key attributes of...

2017
Dongliang Wang Xiaoping Xin Quanqin Shao Matthew Brolly Zhiliang Zhu Jin Chen

Accurate canopy structure datasets, including canopy height and fractional cover, are required to monitor aboveground biomass as well as to provide validation data for satellite remote sensing products. In this study, the ability of an unmanned aerial vehicle (UAV) discrete light detection and ranging (lidar) was investigated for modeling both the canopy height and fractional cover in Hulunber ...

Journal: :journal of rangeland science 2010
m.t. gaemi m. akbarzade sh. abedi

the study of the exclosure effects on the vegetation changes undergrazing and non-grazing conditions in the rangeland areas has particularimportance in the rangeland improvement and revivification projects. theresearch was accomplished in semi-steppe khoybilehvar area, from 1999 to2005. vegetation cover was annually measured within fixed plots during transact.the results showed that during nine...

2000
Scott N. Martens David D. Breshears Clifton W. Meyer

The understory light environment is a key determinant of vegetation pattern and ecosystem processes, and varies spatially perhaps more than any resource used by plants. Understory light varies along gradients of vegetation structure that range from grassland with no woody canopy cover to forest with nearly complete woody canopy cover. Spatial variability in understory light is largely determine...

Journal: :مرتع و آبخیزداری 0
حمید محمدی ، حمیدرضا کریم زاده جمال الدین خواجه الدین

study of soil and plant relationships is nessesery for ecological- based and appropriate management. the objective of this study is to determine the influence of edaphic properties on haloxylon persicum growth and also, indentifing growth limiting soil properties for saxaul. the study was performed through the stratified random sampling and 3 sites were selected as follow: planted strong saxaul...

The protection and improvement of natural resources especially for desert vegetation need a comprehensive recognition of natural resources and relationship on Soil characteristics. One of the most important species growing in sabzevar desert is Stipagrostis pennata and in the current research the relationship between the physicochemical properties of the soils and growth characteristics of the ...

Amir Mirzaei Mossivand, Ardavan Ghorbani Ehsan Zandi Esfahan Farshad Keivan Behjou

The aim of this study was to assess the regional effects of fire on the surface cover and forage production of mountainous rangelands of Delfan County, Lorestan province, Iran. The fire took placed in June 2007 with significant effects on the vegetation characteristics in the study area. Four fire affected sites were selected for sampling and a close area without fire was considered as control....

Journal: :جنگل و فرآورده های چوب 0
سیده کوثر حمیدی تهران منوچهر نمیرانیان تهران جهانگیر فقهی تهران مرتضی شعبانی ساری

one of the most important information in urban forestry is acquaintance of urban landscape’s area or proportion. nowadays, in several countries variable methods are used to achieve this aim. since there is not any complete method to study urban forest’s status in iran, it is impossible to exert authentic management for these resources. hence, in this research, sampling methods and ikonos satell...

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