Western forests are diverse, and a restoration treatment that makes sense in one forest type or region may be entirely inappropriate for another. Some forests, such as high-elevation spruce-fir forests, are adapted to infrequent stand-replacing fires that may occur only every few hundred years. Others, such as the arid ponderosa pine forests of the Southwest, are adapted to frequent low-intensity ground fires. It is essential to discuss forest fire and forest health issues in a manner that recognizes these differences.

Even southwestern ponderosa pine forests were historically diverse. Many, but not all, areas supported open, “park-like” stands. Surveys by early foresters reveal that some areas had as few as 23 trees over 4 inches in diameter per acre, but other areas—especially in canyons, on north-facing slopes, and at higher elevations where ponderosa pine begins to mix with other conifer species—supported considerably more trees (Fulé et al. 1997; Fulé et al. 2003). Restoration treatments that seek to emulate historic conditions must take this site-by-site variability into account. There is, in other words, no single tree density per acre that can be used as a restoration target. Nor can any blanket prescription describe exactly how trees remaining after a restoration treatment should be distributed across the landscape.

Decisions about how to conduct restoration, then, must always be made on a local basis. They must be based both on a scientific understanding of local site characteristics and on consideration of other factors, including social, economic, and political goals. Involvement of local communities, too, is vital both in reaching a common understanding of management goals and in achieving public acceptance of restoration work.