Comparison of five canopy cover estimation techniques in the western Oregon Cascades

نویسندگان

  • Anne C.S. Fiala
  • Steven L. Garman
  • Andrew N. Gray
چکیده

Estimates of forest canopy cover are widely used in forest research and management, yet methods used to quantify canopy cover and the estimates they provide vary greatly. Four commonly used ground-based techniques for estimating overstory cover – line-intercept, spherical densiometer, moosehorn, and hemispherical photography – and cover estimates generated from crown radii parameters of the western Cascades variant of the Forest Vegetation Simulator (FVS) were compared in five Douglas-fir/western hemlock structure types in western Oregon. Differences in cover estimates among the ground-based methods were not related to stand-structure type ( p = 0.33). As expected, estimates of cover increased and stand-level variability decreased with increasing angle of view among techniques. However, the moosehorn provided the most conservative estimates of vertical-projection overstory cover. Regression equations are provided to permit conversion among canopy cover estimates made with the four ground-based techniques. These equations also provide a means for integrating cover data from studies that use different techniques, thus aiding in the ability to conduct synthetic research. Ground-based measures are recommended for specific objectives. Because the FVS-estimated cover levels were consistently lower and more variable than most of the ground-based estimates (by up to 44, 17% on average), ground-based measures of canopy cover may be preferable when accuracy is an important objective. # 2006 Published by Elsevier B.V.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Canopy Structure on Forest Lands in Western Oregon: Differences Amond Forest Types and Stand Ages

McIntosh, Anne C.S.; Gray, Andrew N.; Garman, Steven L. 2009. Canopy structure on forest lands in western Oregon: differences among forest types and stand ages. Gen. Tech. Rep. PNW-GTR-794. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 35 p. Canopy structure is an important attribute affecting economic and ecological values of forests in the P...

متن کامل

Comparative Rates of Western Juniper Afforestation in South-Central Oregon and the Role of Anthropogenic Disturbance*

We examine changes in canopy cover for adult western juniper from the 1960s to 1994 in central Oregon using repeat aerial photography. We compare changes at four sites with a land-use history of minimal anthropogenic disturbance to changes on adjacent sites that have a disturbance history more typical of central Oregon rangelands. Canopy cover increased at all sites, but afforestation on sites ...

متن کامل

Estimation of Forest Canopy Cover: a Comparison of Field Measurement Techniques

Estimation of forest canopy cover has recently been included in many forest inventory programmes. In this study, after discussing how canopy cover is defined, different ground-based canopy cover estimation techniques are compared to determine which would be the most feasible for a large scale forest inventory. Canopy cover was estimated in 19 Scots pine or Norway spruce dominated plots using th...

متن کامل

Design and evaluation of a forest landscape change model for western Oregon

This article describes the design and evaluation of a forest landscape model, called LandMod, developed by scaling a forest gap model to operate at a coarser resolution. LandMod is a spatially explicit, stochastic model designed to simulate forest dynamics in the west-central Oregon Cascades over long time frames (500+ years) and large spatial extents (≥18,000 ha) at a relatively fine grain (0....

متن کامل

The impact of sound land use management to reduce runoff

The study aimed to determine the impact of sound land use management to the runoff in Kabuntalan, Maguindanao in Tamontaka river basin. This was done through simulation and the comparison of the three land cover scenarios such as 2015 land cover, 2025 projected land cover and desired land use to determine its difference in terms of runoff. Hydrologic Engineering Center-Hydrologic Modeling Syste...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2006