نتایج جستجو برای: vertical vegetation structure

تعداد نتایج: 1685994  

Journal: :Remote Sensing 2017
Jake E. Simpson Thomas E. L. Smith Martin J. Wooster

Airborne Light Detection and Ranging (LiDAR) is a survey tool with many applications in forestry and forest research. It can capture the 3D structure of vegetation and topography quickly and accurately over thousands of hectares of forest. However, very few studies have assessed how accurately LiDAR can measure surface topography under forest canopies, which may be important, for example, in re...

2016
Aida Cuni-Sanchez Lee J. T. White Kim Calders Kathryn J. Jeffery Katharine Abernethy Andrew Burt Mathias Disney Martin Gilpin Jose L. Gomez-Dans Simon L. Lewis

Recent studies show widespread encroachment of forest into savannas with important consequences for the global carbon cycle and land-atmosphere interactions. However, little research has focused on in situ measurements of the successional sequence of savanna to forest in Africa. Using long-term inventory plots we quantify changes in vegetation structure, above-ground biomass (AGB) and biodivers...

2013
Keiko Ioki Junichi Imanishi Takeshi Sasaki Youngkeun Song Yukihiro Morimoto Hisashi Hasegawa

Vertical structure is important for understanding forest environment, yet difficult to characterize, especially in temperate heterogeneous forests where the structure is complex. This study used data from a small-footprint airborne laser scanning (ALS) to estimate vegetation coverage in four stratum ranges in a warm temperate forest in Japan: >12 m, 8 12 m, 4 8 m, and 0 4 m in height. Field dat...

2014
Falk Matthias R. D. Pyles S. L. Ustin K. T. Paw L. Xu M. L. Whiting B. L. Sanden MATTHIAS FALK L. XU M. L. WHITING B. L. SANDEN P. H. BROWN

Among the uncertain consequences of climate change on agriculture are changes in timing and quantity of precipitation together with predicted higher temperatures and changes in length of growing season. The understanding of how these uncertainties will affect water use in semiarid irrigated agricultural regions depends on accurate simulations of the terrestrial water cycle and, especially, evap...

2009
Stefano Tebaldini Fabio Rocca

This paper is focused on the recovery of the vertical structure of forested areas from multi-baseline and multipolarimetric SAR surveys at P-Band and L-Band. Results will be shown basing on both P-Band and L-Band airborne data relative to the forested areas within the Krycklan catchment, Norther Sweden, collected in the framework of the ESA campaign BioSAR 2008. The spaceborne case is also cons...

Journal: :Remote Sensing 2012
Geoffrey A. Fricker Sassan Saatchi Victoria Meyer Thomas W. Gillespie Yongwei Sheng

Modeling sub-canopy elevation is an important step in the processing of waveform lidar data to measure three dimensional forest structure. Here, we present a methodology based on high resolution discrete-return lidar (DRL) to correct the ground elevation derived from large-footprint Laser Vegetation Imaging Sensor (LVIS) and to improve measurement of forest structure. We use data acquired over ...

2012
Nicole M. Czarnomski Desireé D. Tullos Robert E. Thomas Andrew Simon

Vegetation growing on the surface of a streambank has been shown to alter the shear stresses applied to the boundary, but basic questions remain regarding the influence of vegetation and streambank configurations on near-bank hydraulics. In the present study, Froudescaled flume experiments were used to investigate how changes in vegetation density (ratio of frontal area to channel area, includi...

2012
Dehua Zhao Dong Xie Hengjie Zhou Hao Jiang Shuqing An

Non-destructive estimation using digital cameras is a common approach for estimating leaf area index (LAI) of terrestrial vegetation. However, no attempt has been made so far to develop non-destructive approaches to LAI estimation for aquatic vegetation. Using the submerged plant species Potamogeton malainus, the objective of this study was to determine whether the gap fraction derived from ver...

2002
Jason B. Drake Ralph O. Dubayah Robert G. Knox David B. Clark J. B. Blair

Accurate estimates of the total biomass in terrestrial vegetation are important for carbon dynamics studies at a variety of scales. Although aboveground biomass is difficult to quantify over large areas using traditional techniques, lidar remote sensing holds great promise for biomass estimation because it directly measures components of canopy structure such as canopy height and the vertical d...

Journal: :Environmental management 2009
Ryan F Limb Samuel D Fuhlendorf Darrel E Townsend

Ecologists are beginning to recognize the effect of heterogeneity on structure and function in arid and semiarid ecosystems. Additionally, the influences of temperature on ecosystems are widely documented, but landscape temperature patterns and relationships with vegetation are rarely reported in ecological studies. To better understand the importance of temperature patterns to the conservation...

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