نتایج جستجو برای: canopy structure

تعداد نتایج: 1579939  

2004
R. Dubayah

In the past, obtaining reliable measurements of key forest canopy metrics has been difficult, even after the development of remote sensing technology. Fortunately, next-generation lidar systems are proving to be useful tools for deriving critical canopy measurements, such as height, structure and biomass. These studies have all focused on empirical comparisons between basic lidar-derived and fi...

Journal: :Revista de biologia tropical 2013
Eric J Fuchs Tatiana Robles James L Hamrick

The spatial distribution of individuals is a fundamental property of most species and constitutes essential information for the development of restoration and conservation strategies, especially for endangered plant species. In this paper we describe the spatial distribution of different size classes of the endangered tropical tree Guaiacum sanctum and the effect of canopy cover on spatial aggr...

2017
Sophie Fauset Manuel U. Gloor Marcos P. M. Aidar Helber C. Freitas Nikolaos M. Fyllas Mauro A. Marabesi André L. C. Rochelle Alexander Shenkin Simone A. Vieira Carlos A. Joly

Light is the key energy input for all vegetated systems. Forest light regimes are complex, with the vertical pattern of light within canopies influenced by forest structure. Human disturbances in tropical forests impact forest structure and hence may influence the light environment and thus competitiveness of different trees. In this study, we measured vertical diffuse light profiles along a gr...

2013
Tasman P. Crowe Mathieu Cusson Fabio Bulleri Dominique Davoult Francisco Arenas Rebecca Aspden Lisandro Benedetti-Cecchi Stanislao Bevilacqua Irvine Davidson Emma Defew Simonetta Fraschetti Claire Golléty John N. Griffin Kristjan Herkül Jonne Kotta Aline Migné Markus Molis Sophie K. Nicol Laure M-L J. Noël Isabel Sousa Pinto Nelson Valdivia Stefano Vaselli Stuart R. Jenkins

Ecosystems are under pressure from multiple human disturbances whose impact may vary depending on environmental context. We experimentally evaluated variation in the separate and combined effects of the loss of a key functional group (canopy algae) and physical disturbance on rocky shore ecosystems at nine locations across Europe. Multivariate community structure was initially affected (during ...

Journal: :Remote Sensing 2017
Elizabeth M. Middleton Uwe Rascher Lawrence A. Corp Karl Fred Huemmrich Bruce D. Cook Asko Noormets Anke Schickling Francisco Pinto Luis Alonso Alexander Damm Luis Guanter Roberto Colombo Petya K. E. Campbell David R. Landis Qingyuan Zhang Micol Rossini Dirk Schuettemeyer Remo Bianchi

The first European Space Agency (ESA) and NASA collaboration in an airborne campaign to support ESA’s FLuorescence EXplorer (FLEX) mission was conducted in North Carolina, USA during September–October 2013 (FLEX-US 2013) at the Parker Tract Loblolly Pine (LP) Plantation (Plymouth, NC, USA). This campaign combined two unique airborne instrument packages to obtain simultaneous observations of sol...

Journal: :Remote Sensing 2014
Jessica N. Hightower A. Christine Butterfield John F. Weishampel

Human land use legacies have significant and long-lasting ecological impacts across landscapes. Investigating ancient (>400 years) legacy effects can be problematic due to the difficulty in detecting specific, historic land uses, especially those hidden beneath dense canopies. Caracol, the largest (~200 km2) Maya archaeological site in Belize, was abandoned ca. A.D. 900, leaving behind myriad s...

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: :Japanese Journal of Crop Science 1977

2012
Jeffrey Rominger Mitul Luhar

This paper summarizes recent advances in vegetation hydrodynamics and uses the new concepts to explore not only how vegetation impacts flow and transport, but also how flow feedbacks can influence vegetation spatial structure. Sparse and dense submerged canopies are defined based on the relative contribution of turbulent stress and canopy drag to the momentum balance. In sparse canopies turbule...

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