Six years of monitoring for ozone injury by the Pacific Northwest Research Station Forest Inventory and Analysis Program are reported. The methods used to evaluate injury, compute an injury index, and estimate risk are described. Extensive injury was detected on ozone biomonitoring sites for all years in California, with ponderosa and Jeffrey pines, mugwort, skunkbush, and blue elderberry showing injury. Little or no injury was detected in Oregon and Washington. The relation of observed injury to ambient ozone levels is discussed. The areas with the highest modeled risk of ozone injury are the areas east of Los Angeles, the southern Sierra Nevada, and portions of the central coast.

In 1994, the Forest Inventory and Analysis (FIA) and Forest Health Monitoring programs of the U.S. Forest Service implemented a national ozone (O3) biomonitoring program designed to address specific questions about the area and percent of forest land subject to levels of O3 pollution that may negatively affect the forest ecosystem. This is the first and only nationally consistent effort to monitor O3 stress on the forests of the United States. This report provides background information on O3 and its effects on trees and ecosystems, and describes the rationale behind using sensitive bioindicator plants to detect O3 stress and assess the risk of probable O3 impact. Also included are a description of field methods, analytic techniques, estimation procedures, and how to access, use and interpret the ozone bioindicator attributes and data outputs such as the national ozone risk map.

An Aquatic and Riparian Effectiveness Monitoring Plan (AREMP) for the Northwest Forest Plan is intended to characterize the ecological condition of watersheds and aquatic ecosystems. So to determine the effectiveness of the Northwest Forest Plan to meet relevant objectives, this report presents the conceptual foundation of options for use in pilot testing and implementing an effectiveness monitoring program for aquatic and riparian systems. The base program would evaluate status and trends of watershed, stream, and riparian conditions by using decision-support models. Although the focus of AREMP is on characterizing ecosystem status and trend, implementing it will also supply information that will be useful in determining causal relations to help explain those trends.