نتایج جستجو برای: forest vegetation

تعداد نتایج: 144457  

Journal: :journal of agricultural science and technology 0
h. asadi department of soil science, faculty of agricultural engineering and technology, university of tehran, karaj, islamic republic of iran. m. honarmand department of soil science, faculty of agricultural sciences, university of guilan, rasht, islamic republic of iran. m. vazifedoust department of soil science, faculty of agricultural sciences, university of guilan, rasht, islamic republic of iran. a. moussavi department of soil science, faculty of agricultural sciences, university of guilan, rasht, islamic republic of iran.

risk assessment of soil erosion, one of the most important land degradation problems worldwide, is very essential for land and water resources management, and development of soil conservation methods. in the present study, the temporal changes of soil erosion risk were assessed from 1987 to 2010, based on the revised universal soil loss equation (rusle) using remote sensing (rs) and geographic ...

2015
Y. Zhang M. Voigt H. Liu

During the past several decades, observational data have shown a faster increase in hot temperature extremes than the change in mean temperature. Increasingly high extreme temperatures are expected to affect terrestrial ecosystem function. The ecological impact of hot extremes on vegetation production, however, remains uncertain across biomes in natural climatic conditions. In this study, we in...

2010
Henry Adams

The fragmentation of forest ecosystems is common in the northeastern United States (Cadenasso, 1997). Many studies have focused on the biotic factors of forest edges. These have shown that edge vegetation is different compositionally and structurally from forest interior vegetation (Brothers, 1992; Luken, 1991; Matlack, 1993; 1994). Steeper climactic gradients are created when trees are removed...

Journal: :Remote Sensing 2014
Paul M. Montesano Guoqing Sun Ralph Dubayah K. Jon Ranson

Satellite-based estimates of vegetation structure capture broad-scale vegetation characteristics as well as differences in vegetation structure at plot-scales. Active remote sensing from laser altimetry and radar systems is regularly used to measure vegetation height and infer vegetation structural attributes, however, the current uncertainty of their spaceborne measurements is likely to mask a...

Journal: :Remote Sensing 2014
Édipo Henrique Cremon Dilce de Fátima Rossetti Hiran Zani

The origin of large areas dominated by pristine open vegetation that is in sharp contrast with surrounding dense forest within the Amazonian lowland has generally been related to past arid climates, but this is still an issue open for debate. In this paper, we characterize a large open vegetation patch over a residual megafan located in the northern Amazonia. The main goal was to investigate th...

2004
E. R. MICHELI J. W. KIRCHNER E. W. LARSEN

Riparian forest vegetation is widely believed to protect riverbanks from erosion, but few studies have quantified the effect of riparian vegetation removal on rates of river channel migration. Measured historical changes in a river channel centreline, combined with mapped changes in floodplain vegetation, provide an opportunity to test how riparian vegetation cover affects the erodibility of ri...

2017
Ram C Sharma Keitarou Hara Hidetake Hirayama

This paper presents the performance and evaluation of a number of machine learning classifiers for the discrimination between the vegetation physiognomic classes using the satellite based time-series of the surface reflectance data. Discrimination of six vegetation physiognomic classes, Evergreen Coniferous Forest, Evergreen Broadleaf Forest, Deciduous Coniferous Forest, Deciduous Broadleaf For...

2015
Chanchan Xu Gang Yang Meng Yang RunGuo Zang

In constructing and visualizing a virtual three-dimensional forest scene, we must first obtain the vegetation distribution, namely, the location of each plant in the forest. Because the forest contains a large number of plants, the distribution of each plant is difficult to obtain from actual measurement methods. Random approaches are used as common solutions to simulate a forest distribution b...

2014
Nghia Pham Minh Chengyi Wang Bin Zou Quang Thi Nguyen

Forest height is one of the most important vegetation vertical structure for many forest management activities. It is closely related with forest biomass and absorption of carbon. PolInSAR is a promising remote sensing technique that has been frequently used for extracting forest height. Recently, there have been plenty of research on the retrieval of vegetation parameters by single frequency s...

2007
L. M. Dupont H. Behling

ODP Site 1078 situated under the coast of Angola provides the first record of the vegetation history for Angola. The upper 11 m of the core covers the past 30 thousand years, which has been analysed palynologically in decadal to centennial resolution. Alkenone sea surface temperature estimates were analysed in centennial resolution. We studied sea surface temperatures and vegetation development...

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