The concept: restoring ecological structure and process in ponderosa pine forests. Pages 37-38

Elimination of the historic pattern of frequent low-inten-sity fires in ponderosa pine and pine-mixed conifer forests has resulted in major ecological disruptions. Prior to 1900, open stands of large, long-lived, fire-resistant ponderosa pine were typical. These were accompanied in some areas by other fire-dependent species such as western larch. Today, as a result of fire exclusion, most stands have dense thickets of small trees and are experiencing insect and disease epi-demics and severe wildfires. These forests cover about 40 million acres in the Western United States and are the focus of concerns about declining forest health (American Forest