Pacific Southwest

Title: Statistical considerations for plot design, sampling procedures, analysis, and quality assurance of ozone injury studies

Author: Arbaugh, Michael; Bednar, Larry

Date: 1996

Source: In: Miller, Paul R.; Stolte, Kenneth W.; Duriscoe, Daniel M.; Pronos, John, technical coordinators. Evaluating ozone air pollution effects on pines in the western United States. Gen. Tech. Rep. PSW–GTR–155. Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture; p. 29-34

Station ID: GTR-PSW-155

Description: The sampling methods used to monitor ozone injury to ponderosa and Jeffrey pines depend on the objectives of the study, geographic and genetic composition of the forest, and the source and composition of air pollutant emissions. By using a standardized sampling methodology, it may be possible to compare conditions within local areas more accurately, and to apply the results to larger geographical contexts, such as pine populations within and among watershed areas. We present recommendations in this chapter to develop plot design and sampling strategies that follow established principles of observational studies, and we discuss the usefulness of indices and need for quality assurance for long–term monitoring of ozone injury to ponderosa and Jeffrey pine. The recommendations pertain only to the goals and conditions unique to ozone pollution impacts on mixed conifer, ponderosa and Jeffrey pine forests of the Western United States. Differences in climate, physiology, and air pollutant composition and exposure patterns will likely alter sample design and analysis needs for other forest types and locations. One of the principal objectives of long–term sampling by repeated observations is to document tree and stand changes through time. In this paper sampling methods will be chosen to optimize long–term, repeated observations of tree populations within a watershed area, and to compare damage between watersheds. The specific questions will be addressed about plot design, the method used to locate plots, and the optimal sample size of branches per tree and trees per plot needed to estimate summary statistics and indices.

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Citation

Arbaugh, Michael; Bednar, Larry  1996.  Statistical considerations for plot design, sampling procedures, analysis, and quality assurance of ozone injury studies.   In: Miller, Paul R.; Stolte, Kenneth W.; Duriscoe, Daniel M.; Pronos, John, technical coordinators. Evaluating ozone air pollution effects on pines in the western United States. Gen. Tech. Rep. PSW–GTR–155. Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture; p. 29-34.