The forest resource of western Montana /

Abstract

In 1925 the sawtimber volume in Western Montana was estimated to be about 37.5 billion board feet (2). 1 Forest Survey compilations in 1949 (4) based on field surveys prior to World War II raised the estimates to 39.7 billion. The most recent estimates, given in this report, show a present sawtimber volume of 73.5 billion board feet. Startling though this difference is, it will not surprise anyone who has followed the history of timber utilization and inventory practices in this country. Inventories have been geared largely to obtaining estimates of currently merchantable timber, rather than the total stand. Also, timber cruisers through the years have traditionally been cautious souls. They have found it more acceptable practice to underestimate rather than risk an overestimate. These two factorsrapidly changing utilization and conservative estimateshave generally resulted in rapid obsolescence of inventory estimates. The trend toward more intensive utilization during the period between old and new surveys is exemplified in Western Montana. Since World War II, the stumpage value of all species has risen. As a result, 1.5 million acres are today included as commercial that previously had been classified as noncommercial. This increase has been accompanied by a reduction of 1 million acres in nonstocked and seedling and sapling area and an increase of about 2.6 million acres of sawtimber. A substantial area within the 1910 burn has reached pole size, and about an equal area of the 1942 poletimber has become sawtimber. Changes in the economic importance of species and closer utilization with respect to tree size have both contributed to higher current estimates. Prior to World War II, timber utilization rested heavily on white pine and ponderosa pine. Other species were far less valuable. As a consequence, even the early estimates of white pine volume were very realistic and those of ponderosa pine were not much in error. In contrast, the inventory of other species was at best very rough. Today there are 61 billion board feet of Douglas-fir, western larch, Engelmann spruce, lodgepole pine, and the minor species. This amounts to more than twice the volume of these species reported earlier. Improved inventory techniques have been another major development. Estimates from earlier surveys were based largely on the compilation of public and private cruises, which varied greatly in objectives and standards. Although Forest Survey made check cruises to adjust estimates to a common standard, the total result could not be statistically evaluated for reliability. Estimates presented in this report are based on greatly improved sampling procedures that reduce the risk of bias. Timber inventory procedures are constantly being improved. Although it is now possible with the sampling system used in Western Montana to estimate volumes within prescribed rates of accuracy, the need today is for additional information that describes management needs and opportunities. Currently this Experiment Station is giving much attention to the ...