the aim of study was to evaluate qualitative and quantitative characteristics of old trees in pattom and namkhaneh districts in the nowshahr, northern iran. the trees quantitative characteristics of dbh, total height, slenderness coefficient, trunk height, crown length, buttress height, and canopy cover area and qualitative characteristics of crown and trunk, i.e., health, vitality, and concurr...

Wyoming big sagebrush (Artemisia tridentata wyomingensis) treatments are often implemented to improve breeding habitat for greater sage-grouse (Centrocercus urophasianus), a species of considerable conservation concern. In 2008 and 2009, we measured vegetation structure available to sage-grouse for breeding at 19 sites that were prescribed burned during 1990–1999 and 2000–2006, 6 sites that wer...

Particulate Hg (pHg) is a component of smoke from biomass burning and has the potential for local redeposition. Throughfall (precipitation collected beneath a conifer or deciduous canopy) and open precipitation samples were collected pre- and postfire in 2005 and 2006 using passive precipitation collectors across the Superior National Forest, located in northern Minnesota, USA. Samples were col...

The study of the exclosure effects on the vegetation changes undergrazing and non-grazing conditions in the rangeland areas has particularimportance in the rangeland improvement and revivification projects. Theresearch was accomplished in semi-steppe KhoyBilehvar area, from 1999 to2005. Vegetation cover was annually measured within fixed plots during transact.The results showed that during nine...

–Trees in many forests affect the soils and plants below their canopies. In current high-density southwestern ponderosa pine (Pinus ponderosa) forests, managers have opportunities to enhance multiple ecosystem values by manipulating tree density, distribution, and canopy cover through tree thinning. I performed a study in northern Arizona ponderosa pine-Gambel oak (Quercus gambelii) forests to ...

0099-1112/12/7807–715/$3.00/0 © 2012 American Society for Photogrammetry and Remote Sensing Abstract Tree canopy cover is a fundamental component of the landscape, and the amount of cover influences fire behavior, air pollution mitigation, and carbon storage. As such, efforts to empirically model percent tree canopy cover across the United States are a critical area of research. The 2001 nation...

With fire suppression, many western forests are expected to have fewer gaps and higher stem density of shade-tolerant species as light competition becomes a more significant influence on stand pattern and composition. We compared species composition, structure, spatial pattern, and environmental factors such as light and soil moisture between two old-growth forests: Pacific Northwest western he...

We examined patterns of shrub species diversity relative to landscape-scale variability in environmental factors within two watersheds on the coastal flank of the Santa Ynez Mountains, California. Shrub species richness and dominance was sampled at a hierarchy of spatial units using a highpowered telescope from remote vantage points. Explanatory variables included field estimates of total canop...

This study used an affordable ground-based portable LiDAR system to provide an understanding of the structural differences between old-growth and secondary-growth Southeastern pine. It provided insight into the strengths and weaknesses in the structural determination of portable systems in contrast to airborne LiDAR systems. Portable LiDAR height profiles and derived metrics and indices (e.g., ...

Woody plant encroachment into grasslands and rangelands is a world-wide phenomenon but detailed descriptions of changes in geographical distribution and infilling rates have not been well documented at large land scales. Remote sensing with either aerial or satellite images may provide a rapid means for accomplishing this task. Our objective was to compare the accuracy and utility of two types ...