32 BULLETIN 426^ U. S. DEPAKTMENT OF AGRICULTURE. 



Studies of the grades cut from pine logs of various dimensions indi- 

 cate that knotty trees under 32 inches in diameter produce largely 

 common and box lumber, which can be marketed at present only at a 

 loss or at a very slight profit. Such trees may profitably be left for 

 seed or protection and to form a part of the next cut, for which they 

 will be more valuable because of increased growth, higher selling 

 prices, and a greater percentage of high-grade product as the result 

 of natural pruning. 



The white fir and cedar in sugar-pine stands are now difficult to 

 market at a profit above the bare cost of production. Both of these 

 species have greater prospective than present values — the former for 

 pulp as well as lumber, the latter for pencil stock and other refined 

 uses. It appears to be wise management, therefore, to remove only 

 the dead, diseased, and mature trees which will not remain mer- 

 chantable until the next cut. Young sugar pine reproduction 

 requires shade in youth, and these species are left to furnish it in 

 preference to others of more value. Their reproduction will endure 

 shade, and is therefore a va,luable agent in preventing brush from 

 securing control of cut-over areas. 



In applying the above principles on National Forests the cutting is 

 so regulated as to create conditions favorable to the securing of a 

 stand of young trees through natural regeneration, because the per- 

 petuation of the forest depends upon this. Sugar-pine seed is eaten 

 in large quantities by rodents and birds, and since young trees 

 require protection from too severe light for the first 10 years of their 

 life the securing of young growth is rather a difficult problem. 

 Eventually, when transportation and market conditions allow of cut- 

 ting over areas frequently for a small volume of timber, the shelter- 

 wood system of cutting will probably be applied where sugar pine 

 makes up 20 per cent or more of the stand. This system provides for 

 several successive operations separated by short intervals; the first 

 opens up the stand slightly to afford just sufficient light to stimulate 

 the seed-producing capacity of the remaining trees and to secure young 

 growth; the second follows after reproduction has been secured 

 and partiaUy frees it from shade; the third removes the remaining 

 mature trees. At present, however, this system would not j)ay. 



In the sugar-pine type the forest is made up of groups of mature 

 sugar pine and its common associates, interspersed with openings and 

 approximately even-aged groups of younger trees of the same com- 

 position, as well as of trees of various ages and species occurring 

 singly. On areas where the occurrence is in groups the clumps of 

 mature trees are cut clean and the immature are left. Sometimes it is 

 necessary to leave a mature tree which may occur in an immature 

 group from which it could not be removed, or to remove a few imma- 

 ture trees from mature groups because of the likelihood of wind 

 damage or to free reproduction from shade. In cuttings of this 



