نتایج جستجو برای: forest vegetation

تعداد نتایج: 144457  

2008
Z. Zhang Guoqing Sun

Vegetation spatial structure including plant height, biomass, vertical and horizontal heterogeneity, is an important factor influencing the exchanges of matter and energy between landscape and atmosphere, and the biodiversity of ecosystems. Regional and global forest biomass and forest structure estimation is essential for understanding and monitoring ecosystem responses to human activities and...

Journal: :Remote Sensing 2016
Panpan Zhao Dengsheng Lu Guangxing Wang Chuping Wu Yujie Huang Shuquan Yu

The data saturation problem in Landsat imagery is well recognized and is regarded as an important factor resulting in inaccurate forest aboveground biomass (AGB) estimation. However, no study has examined the saturation values for different vegetation types such as coniferous and broadleaf forests. The objective of this study is to estimate the saturation values in Landsat imagery for different...

Journal: :مرتع و آبخیزداری 0
سید حمزه حسینی کهنوج دانشجوی کارشناسی ارشد مرتع داری دانشکدة منابع طبیعی دانشگاه تربیت مدرس رضا عرفان زاده دانشیار گروه مرتع داری دانشکدة منابع طبیعی دانشگاه تربیت مدرس حسین آذرنیوند استاد گروه احیای مناطق خشک و کوهستانی، دانشکدة منابع طبیعی دانشگاه تهران

this study aimed to investigate the effect of habitat kind on soil seed bank characteristics viz. density diversity, richness and similarity between seed bank and above ground vegetation. two different habitats (grassland and forest) were selected in vaz, mazandaran province. the grassland habitat located in the upper end of the forest habitat, adjacent to each other. then in each habitat, 7 tr...

2012
E. Pajorova Ladislav Hluchý

Every year, forest fires, floods and landslides cause enormous damage of vegetation and fauna, environment and property and bind significant human resources. Particularly in national parks and natural reservations, unique areas of high degree of protection can be devastated by fire. For instance, during the destructive forest fire in the Slovak Paradise National Park (Slovakia) in 1976, very un...

2011
Sarah J. Ivory Anne-Marie Lézine Annie Vincens Andrew S. Cohen

a r t i c l e i n f o Fossil pollen analyses from northern Lake Malawi, southeast Africa, provide a high-resolution record of vegetation change during the Pleistocene/Holocene transition (~ 18–9 ka). Recent studies of local vegetation from lowland sites have reported contrasting rainfall signals during the Younger Dryas (YD). The Lake Malawi record tracks regional vegetation changes and allows ...

2013
DANIEL G. GAVIN LINDA B. BRUBAKER D. NOAH GREENWALD

The mode and tempo of forest compositional change during periods of rapid climate change, including the potential for the fire regime to produce nonlinear relationships between climate and vegetation, is a long-standing theme of forest ecological research. In the old conifer forests of the coastal Pacific Northwest, fire disturbances are sufficiently rare that their relation to climate and thei...

2002
S. M. JOY R. M. REICH R. T. REYNOLDS S. M. Joy

Traditional land classification techniques for large areas that use Landsat Thematic Mapper (TM) imagery are typically limited to the fixed spatial resolution of the sensors (30 m). However, the study of some ecological processes requires land cover classifications at finer spatial resolutions. We model forest vegetation types on the Kaibab National Forest (KNF) in northern Arizona to a 10-m sp...

2012
Jorge Luis Rentería Mark R. Gardener F. Dane Panetta Rachel Atkinson Mick J. Crawley

Originally from Asia, Rubus niveus has become one of the most widespread invasive plant species in the Galapagos Islands. It has invaded open vegetation, shrubland and forest alike. It forms dense thickets up to 4 m high, appearing to displace native vegetation, and threaten the integrity of several native communities. This study used correlation analysis between a R. niveus cover gradient and ...

2002
T. S. RUPP A. M. STARFIELD

In the boreal biome, fire is the major disturbance agent affecting ecosystem change, and fire dynamics will likely change in response to climatic warming. We modified a spatially explicit model of Alaskan subarctic treeline dynamics (ALFRESCO) to simulate boreal vegetation dynamics in interior Alaska. The model is used to investigate the role of black spruce ecosystems in the fire regime of int...

2015
Guoqing Li Zhongming Wen Ke Guo Sune Linder Eric J. Jokela

A risk assessment of vegetation zone responses to climate change was conducted using the classical Holdridge life zone model on the Loess Plateau of Northwest China. The results show that there are currently ten vegetation zones occurring on the Loess Plateau (1950–2000), including alvar desert, alpine wet tundra, alpine rain tundra, boreal moist forest, boreal wet forest, cool temperate desert...

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