Environmentally related restrictions on the timber harvesting capability of a national forest: A case study

In response to influences predominantly external to the United States Department of Agriculture, Forest Service, and beginning in the 1970s, the latitude and intensity of timber management activities on the National Forests have been increasingly limited through the imposition of environmentally induced constraints. Quantitative information on the relative costs and benefits of imposing environmentally induced constraints is generally lacking, and this has hindered the proper evaluation of the constraints. To generate some of this needed information, the author examined the effects of meeting environmental goals on National Forest timber harvesting capability by developing 20 simulated harvest schedules for a case study in northern California. Using available data and the simulation model FOR-PLAN, the schedules were designed to identify the effects of land withdrawal, retention of old-growth stands, minimum rotation, geographic dispersion, and limitation on the use of herbicides on allowable timber cutting. Monitored indices included first-decade harvesting, total harvest in the first five decades, long-run sustained-yield average, species concentration, acres clearcut, and distribution of ending-age classes. In addition, these economic indices were monitored by two demand formulations (present net worth and present net benefit after 16 decades), total costs and revenues in the first decade, and cost per million cubic feet. Two different price assumptions were modeled—each representing distinctly contrasting conditions. The results suggest that the allowable harvest capability of the case-study forest was significantly reduced when measures were taken to reach environmental goals.