584 A NATIONAL PLAN FOR AMERICAN FORESTRY 



available for the removal of these hardwoods whenever such treat- 

 ment is needed. Similarly, improvement of the mixed hardwood 

 stands on the best sites in the Appalachians by thinnings and removal 

 of the worthless trees would be profitable. 



Throughout the national-forest cutting areas it has been the prac- 

 tice to require timber purchasers to cut down trees worthless because 

 of disease or other cause, thus ridding the stands of trees which would 

 spread disease to others and improving growth conditions. The cost 

 of this work has been allowed for in fixing stumpage values. In the 

 California national forests, for example, fully 200,000 acres of cutting 

 area have been thus treated. 



Disposal of the slash left from timber-sale cuttings has long been a 

 problem. Where the fire hazard is relatively low, as in the central and 

 southern Rocky Mountains, the limbs can be lopped from the tops 

 and left scattered on the ground, thus improving soil conditions as 

 they decay, and either improving or offering no obstacle to the chances 

 for natural reproduction to come in. In the northern Rocky Mountains 

 in Idaho, and throughout Washington, Oregon, and California, fire 

 protection has appeared to require piling and burning of the slash 

 except in the coast Douglas fir stands where broadcast burning is 

 required. This is expensive and silviculturally undesirable in its 

 effect on natural regeneration. Experiments in partial piling and 

 burning, with increased protective measures in other ways, are being 

 tried in representative California pine stands, and may develop a 

 compromise method less costly and more desirable silviculturally. 

 No such prospect is immediately in sight for the broadcast-burned 

 Douglas fir slash problem, but the possibilities of selective logging 

 by area, leaving more uncut timber to constitute breaks in the large 

 slash area, may make it possible to leave a considerable portion of the 

 slash areas unturned. 



This selective-logging development also bids fair to help materially 

 in solving the problem of leaving adequate seed trees in the hitherto 

 clear-cut Douglas fir areas. The first plan of leaving individual trees 

 was largely unsuccessful because of loss through their being blown 

 down, or being killed by the slash fire or subsequent accidental fires. 

 A modified plan of leaving trees in strips or groups has been more suc- 

 cessful, but not wholly so. If the selective-logging principle proves 

 capable of general application, many stands of present low market 

 value will be left well distributed throughout the cutting areas, 

 awaiting future cutting, and the seed supply problem will be largely 

 solved. 



One major objective in the development of national-forest cutting 

 systems is to obtain adequate reproduction following cutting. On 

 many selectively cut areas the stand left constitutes the major part 

 of the desired stocking, and extensive reproduction is not expected 

 until after the second or third cutting. Elsewhere, where thinner 

 stands have to be left, or larger openings made, prompt restocking 

 is the aim; as it is invariably where clean cutting is practiced. Both 

 systematic examinations and extensive observations on cut-over areas 

 show that in general after a reasonable lapse of time, usually not more 

 than 10 to 15 years, restocking is satisfactory on 85 to 100 percent of 

 cut-over land. There are exceptions to this in the Engelmann spruce 

 type of the northern Rocky Mountains and in Arizona and New 

 Mexico, where not more than 50 percent success has been obtained. 



