نتایج جستجو برای: reduction of forest canopy

تعداد نتایج: 21203187  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه بیرجند 1388

a significant problem in multicarrier communication systems is the necessity to reduce the value of papr (peak-to-average power ratio) of transmitting signal. in this thesis we study the effect of the system parameters such as coding and modulation types on papr and ultimate ber in a mc-cdma system. in this study we consider fading channel as well as the nonlinearity of transmitter’s amplifier ...

2015
Yi Jin Hong Qian Mingjian Yu Mingxi Jiang

Investigating patterns of phylogenetic structure across different life stages of tree species in forests is crucial to understanding forest community assembly, and investigating forest gap influence on the phylogenetic structure of forest regeneration is necessary for understanding forest community assembly. Here, we examine the phylogenetic structure of tree species across life stages from see...

Journal: :Remote Sensing 2016
Youven Goulamoussène Caroline Bedeau Laurent Descroix Vincent Deblauwe Laurent Linguet Bruno Hérault

Canopy height is a key variable in tropical forest functioning and for regional carbon inventories. We investigate the spatial structure of the canopy height of a tropical forest, its relationship with environmental physical covariates, and the implication for tropical forest height variation mapping. Making use of high-resolution maps of LiDAR-derived Digital Canopy Model (DCM) and environment...

2017
Sandra R Holden Brendan M Rogers Kathleen K Treseder Michael Alonzo Douglas C Morton Bruce D Cook Hans-Erik Andersen Chad Babcock Robert Pattison

Fire in the boreal region is the dominant agent of forest disturbance with direct impacts on ecosystem structure, carbon cycling, and global climate. Global and biome-scale impacts are mediated by burn severity, measured as loss of forest canopy and consumption of the soil organic layer. To date, knowledge of the spatial variability in burn severity has been limited by sparse field sampling and...

Esmaiel Khosropour Kamran Pourmoghadam Kimia Pourmoghadam, Maziar Haidari,

Physiological factors have effects on most forest parameters such as forest classification so that understanding knowledge about this subject is important to manage forests. The forests of Sorkhake-sanjabi village with area of 1645 ha located in Eslam Abad city, Kermanshah province, Iran were selected. 23 sample plots with rectangular shape (40m*50m) were selected and the species, origin of spe...

2005
M. Biradar Chandrashekhar Sameer Saran P. L. N. Raju P. S. Roy

Monitoring of forest cover is an essential tool for sustainable management of natural resources. Woody green cover can better maintained and managed by identification of forest gaps and their subsequent refilling. Forest canopy density mapping is one of the tools used to identify such canopy openings and most useful parameter to consider in the planning and implementation of afforestation and r...

Journal: :Remote Sensing 2018
Mengjia Wang Rui Sun Zhiqiang Xiao

Mapping the regional distribution of forest canopy height and aboveground biomass is worthwhile and necessary for estimating the carbon stocks on Earth and assessing the terrestrial carbon flux. In this study, we produced maps of forest canopy height and the aboveground biomass at a 30 m spatial resolution in Maryland by combining Geoscience Laser Altimeter System (GLAS) data and Landsat spectr...

Journal: :Ecological applications : a publication of the Ecological Society of America 2014
David K Skelly Susan R Bolden L Kealoha Freidenburg

Vernal ponds are often treated as protected environments receiving special regulation and management. Within the landscapes where they are found, forest vegetation frequently dominates surrounding uplands and can grow to overtop and shade pond basins. Two bodies of research offer differing views of the role of forest canopy for vernal pond systems. Studies of landscape conversion suggest that r...

Density and diversity of birds in two different forest zones, namely, Shasta Kalateh Protected Forest and Alangdareh Recreational Forest, were estimated and compared. Birds and environmental variables were recorded within 25 m radius in 100 sampling points. The first axis of Canonical Component Analysis segregated two main groups of birds. The first group consisted of Black Woodpecker, Great Sp...

2007
C. Ginzler

The objective of this study is to test the feasibility of nation-wide medium footprint airborne laser scanning (ALS) data for derivation of forest parameters. The comparison of canopy closure as one important parameter for many forest functions derived from ALS data and aerial photo interpretation was conducted. The present study was carried out in the framework of the Swiss National Forest Inv...

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