A NATIONAL PLAN FOR AMERICAN FORESTRY 



917 



character to make net growth should be removed wherever that can be 

 done at a moderate profit. 



In these stands the larger trees are generally found in groups, and 

 such selection will result in clear cutting on from 5 to 15 percent of the 

 area in each cutting cycle. The resultant open spots will provide 

 suitable conditions for regeneration of Douglas fir which, except in the 

 fog belt and at high altitudes, is usually the most desired species. 

 Complete slash disposal by the methods common in the region will 

 usually be practiced on these spots. Either sufficient Douglas fir seed 

 trees must be left to seed in an adequate proportion of fir on these spots 

 or wide-spaced planting may be necessary as discussed under the 

 spruce-hemlock type. The total number of trees removed will 

 hardly exceed 6 to 8 per average acre. About 40 to 60 trees from 6 to 



FIGURE 4. Distribution of cubic volume by diameter classes on average acre, old growth Douglas fir with 



hemlock, western Oregon. 



40 inches in diameter will remain; except for the open spots noted, the 

 forest cover will be very slightly disturbed. 



The residual stand will be in shape to accelerate its growth, 

 especially in the lower diameter classes, which will be mainly hemlock. 

 Although no precise data are available from such cuttings, it is known 

 that hemlock accelerates its growth rapidly when released from crown 

 and root competition. A net current annual growth of 400 to 800 

 board feet per acre can reasonably be counted on when the growth of 

 the smaller tree classes increases. If the first cut passes over the 

 whole forest property in 20 years, the second cut can begin immedi- 

 ately afterward in stands rebuilt to about 30,000 board feet per acre. 

 The second cut should not greatly exceed the rate of growth during the 

 cutting cycle, or about 10,000 feet per acre. The decision as to the 

 quantity of timber to be removed in that cut should, however, be 

 deferred until the time for the cut has come. It may then be desirable 

 either to remove more of the growing stock or to rebuild it to some 

 extent. 



Under this procedure the returns from about 20,000 feet per acre 

 of the first cut might be applied to the construction of permanent 



