land in National Forests. Of this total, 71 mil- 

 lion acres have been classed as "commercial;" 

 that is, the timber growing base. 



In this report we will answer the following 

 questions: 



• HAS THE TIMBER GROWING BASE 

 BEEN PROPERLY DETERMINED? 

 IN OTHER WORDS, HAVE ALL THE 

 FACTORS AFFECTING THE SUIT- 

 ABILITY AND AVAILABILITY OF 

 THE FOREST FOR TIMBER GROW- 

 ING BEEN ADEQUATELY TAKEN 

 INTO ACCOUNT? 



• HAS THE TIMBER GROWING BASE 

 BEEN SUBDIVIDED IN A MEAN- 

 INGFUL WAY THAT REFLECTS 

 TIMBER GROWING OPPORTUNI- 

 TIES AND PROBLEMS? 



• HOW CAN THE CLASSIFICATION 

 OF FOREST LAND FOR TIMBER 

 PRODUCTION PLANNING BE 

 IMPROVED? 



This study has been directed by the Inter- 

 mountain Forest and Range Experiment Sta- 

 tion. However, it has been a cooperative en- 

 deavor, involving National Forest and Regional 

 Office personnel in the six Forest Service Re- 

 gions headquartered at: Missoula, Montana; 

 Denver, Colorado; Albuquerque, New Mexico; 

 Ogden, Utah; San Francisco, California; and 

 Portland, Oregon. Much of the work in connec- 

 tion with this study was done by National For- 

 est Systems people and much of their thinking 

 has gone into the study. The conclusions drawn 

 in this report, however, are solely the responsi- 

 bility of the Intermountain Forest and Range 

 Experiment Station. 



A word of caution! Only six National For- 

 ests, or portions thereof, were analyzed to de- 

 rive study data and other information pre- 

 sented here. 



Lolo National Forest (portion), 

 Arapaho National Forest, 

 Coconino National Forest, 

 Boise National Forest (portion), 

 Klamath National Forest — East 



Working Circle, 

 Gifford Pinchot National Forest — 



Gifford Pinchot Working Circle. 



Selection of the six Forests was based pri- 

 marily on convenience, but they presumably 

 represent the range of variation in land and land 

 use factors. However, collectively they may or 

 may not represent the average situation in the 

 West; we simply don't know. Moreover, the 

 fact that we identify and discuss categories in 

 this study beyond those intended in the origi- 

 nal survey reduces the reliability of the data. 

 They are useful only in describing the problem 

 of forest stratification and indicating the gener- 

 al magnitude of the factors considered. 



To recapitulate, the specific purpose of this 

 study is to take a first step toward clarifying the 

 issue of identifying and stratifying the timber 

 growing base. This is an exploratory study to 

 determine if past estimates of the timber grow- 

 ing base (commercial forest area) in the western 

 National Forests are reasonably accurate. The 

 findings on the following pages are based partly 

 on an evaluation of physically measurable fac- 

 tors and partly on an appraisal of the inventory 

 system in relation to the purposes for which the 

 timber data are to be used. 



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