38 BULLETIN 418, U. S. DEPARTMENT OF AGRICULTUEE. 



Yellow pine in its middle life and old age demands so much 

 light and gromid space that the soil is put to the most intensive use 

 only when the forests are uneven-aged, so that the younger trees may 

 pass their slow-growing sapling stage in the gaps between the big trees. 



The system of cutting which seems to be ideal for this type of 

 forest is a form of selection cutting. Periodic cuttings are made, 

 in each of which all the overmature and thoroughly ripe trees in the 

 stand and all the defective ones are removed; and the sapHngs, 

 poles, and young, thrifty trees are left standing to form the basis 

 for the next crop. No tree is removed until it has reached its major- 

 ity, so to speak, and no old, slow-growing tree is allowed to stand 

 and occupy space which should be devoted to young and rapid- 

 growing trees. In this way the forest is kept at its maximum pro- 

 ductivity and the continuity of the forest cover is not interrupted. 

 In each cutting, under the practice of the Forest Service in Oregon, 

 from 10 to 30 per cent of the volume of the stand (above 12 inches 

 in diameter) is left. This is equivalent to 55 per cent of the trees 

 over 12 inches in diameter by number. It is anticipated that a 

 cuttmg of this character may be made at intervals of from 40 to 60 

 years, and that there wiU be a yield sufficient to justify logging. 



Each tree which is to be cut is marked or "blazed" with an ax 

 by a woodsman who has experience, a trained eye, and good judg- 

 ment. He decides for every tree as he passes through the forest 

 whether it shall be cut or reserved. A woodsman may effectually 

 mark in a day 40 acres, or half a milhon feet. It is customary to 

 set an approximate diameter hmit of from 16 to 22 inches, the 

 majority of the trees above wliich hmit are cut, and those below 

 left; in actual practice this diameter hmit must be very elastic, it 

 often being wise silviculturally to reserve a tree 30 or more inches 

 in diameter while one of 14 inches must be cut. 



The following classes of trees should be cut. They are arranged 

 according to the desirabihty of their removal: 



(a) AH spike-topped, seriously fire-scarred, lightniag-struck, or 

 otherwise defective, yet merchantable, trees. 



(b) All insect-infested and conky trees. 



(c) All suppressed trees which apparently would not thrive and 

 make good growth even if released. 



(d) AH thoroughly mature trees of all species which apparently wiU 

 not survive until the next cutting. (In this class should be included aU 

 trees hable to windthrow, which is a serious menace on certain sites.) 



(e) Enough of the younger trees which would probably survive 

 until the next cutting to give the remaining trees plenty of room for 

 optimum growth and allow the saplings and seedlings to receive over- 

 head hght.^ The cuttmg, therefore, should be in the nature of an 

 improvement cutting. Though the trees that are left are not 

 reserved as seed trees, but rather as the basis for the next cut, many 



1 Manuscript report by Forest Supervisor M. L. Merritt. 



