نتایج جستجو برای: canopy cover perimeter

تعداد نتایج: 127446  

Journal: :Remote Sensing 2017
Matthew J. Macander Gerald V. Frost Peter R. Nelson Christopher S. Swingley

Ecosystem maps are foundational tools that support multi-disciplinary study design and applications including wildlife habitat assessment, monitoring and Earth-system modeling. Here, we present continuous-field cover maps for tundra plant functional types (PFTs) across ~125,000 km2 of Alaska’s North Slope at 30-m resolution. To develop maps, we collected a field-based training dataset using a p...

2004
Guo-Yue Niu Zong-Liang Yang Katherine G. Jackson

[1] This paper addresses the effects of canopy physical processes on snow mass and energy balances in boreal ecosystems. We incorporate new parameterizations of radiation transfer through the vegetation canopy, interception of snow by the vegetation canopy, and under-canopy sensible heat transfer processes into the Versatile Integrator of Surface and Atmosphere (VISA) and test the model results...

2015
Carlos Poblete-Echeverría Sigfredo Fuentes Samuel Ortega-Farías Jaime Gonzalez-Talice Jose Antonio Yuri

Leaf area index (LAI) is one of the key biophysical variables required for crop modeling. Direct LAI measurements are time consuming and difficult to obtain for experimental and commercial fruit orchards. Devices used to estimate LAI have shown considerable errors when compared to ground-truth or destructive measurements, requiring tedious site-specific calibrations. The objective of this study...

Ferula pseudalliacea (Bitter asafetida) is an endemic medicinal plant grown in the center of Iran, which is used in pharmaceutical industries. There is less report about its habitat characteristics and distribution in Iran. So, this research was conducted to study the effects of topography and soil properties on distribution of this species in Yazd Province, Iran in 2016 and 2017. Two habitats ...

2006
XIN QU ALEX HALL

The strength of snow-albedo feedback (SAF) in transient climate change simulations of the Fourth Assessment of the Intergovernmental Panel on Climate Change is generally determined by the surfacealbedo decrease associated with a loss of snow cover rather than the reduction in snow albedo due to snow metamorphosis in a warming climate. The large intermodel spread in SAF strength is likewise attr...

2006
R. S. Nuske

Canopy gaps play an essential role in continuous cover forests, as they have a strong effect on regeneration dynamics and species composition. However, canopy gaps have been widely neglected in current monitoring and planning practices, which might be caused by the fact that mapping of canopy gaps from the ground is labour-intensive, tedious, and error prone. An approach to automated canopy gap...

Journal: :Australian Journal of Agricultural and Resource Economics 2013

2009
David Patrick Murray

The spatial distributions of four plant species native to Asia, yet considered invasive in southwestern Virginia, were studied in order to produce predictive habitat maps. The study took place in the mountains to the north of Blacksburg, VA, on National Forest lands. A random GPS survey of each of the four species, Microstegium vimineum, Lonicera japonica, Rosa multiflora and Elaeagnus umbellat...

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