The Author
David C. Chojnacky is a Research Forester in the Bark
Beetle Disturbance Ecology Research Work Unit at Rocky
Mountain Research Station in Logan, UT. He holds a
Ph.D. degree in forest biometry from Colorado State
University. His research interests include forest measurements, sampling, wildlife habitat assessment, bark
beetle hazard rating, and dryland forests.
Research Summary
The Forest Inventory and Analysis (FIA) group within
the Forest Service, U.S. Department of Agriculture, conducts forest resource inventories nationwide with various
sample designs. This paper documents the use of double
sampling for FIA inventories in the Interior West. Results
show that 18 equations describe the entire inventory
summarization process for estimating population totals
and means, and respective variances. Most equations
are for standard use of double sampling, but equations
are also given for a ratio method and a special method
for data defined by county and land ownership. Inventory
data from 800,000 ha of forest land in southern Idaho are
used to illustrate application of several equations