34 BULLETIN 1061, U. S. DEPARTMENT OF AGRICULTURE. 



examinations permit of the announcement without reserve that the 

 timber of longleaf pine is in no way affected by the tapping for 

 turpentine. It is further pointed out that in this statement the 

 chemical as well as the mechanical properties are considered, and 

 thus all doubt as to the comparative durability of timber from bled 

 and unblecl trees is eliminated. 



Preliminary studies of the effect of turpentining upon second- 

 growth longleaf pine indicate, as a result, some check in the rate of 

 growth for an indefinite period of perhaps two to four years fol- 

 lowing operations, depending on the severity of the bleeding of the 

 tree. Locally near the face, growth takes place rapidly on account 

 of an apparent effort of the tree to heel the wound, making very 

 favorable conditions of the wood for later working. Additional in- 

 formation on this particular phase of growth is much needed. 



CUTTING. 



Thrifty, well-stocked stands of longleaf soon become overcrowded, 

 and a great competition arises among the trees, the foliage seeking 

 for light and the roots for soil moisture. This should be closely 

 looked after by the owner. Longleaf does not readily thin itself 

 by the natural dying-out process, but many of the smaller trees may 

 live years in a practically dormant condition. The stronger trees 

 gradually crowd and kill the weaker individuals. If such timber 

 is left unthinned, big losses may be expected in the potential timber- 

 producing power of the stand. 



With some kinds of trees and forests it is more profitable if the 

 largest trees are cut and the smaller ones are allowed to grow and 

 take the places of those that have been cut. This system, however, is 

 not generally to be recommended for longleaf pine. The method of 

 cutting believed to be most applicable to longleaf consists in thin- 

 ning from the bottom upward, that is, in removing first the less 

 thrifty, overtopped, diseased, and unpromising trees. In crowded 

 groups, good-sized trees should sometimes be removed. The cooler 

 part of the year affords the only reason that is safe against danger- 

 ous insect menace following cutting operations. (See under " Insects, 

 Disease, and Wind.") Such thinnings should be made as needed, 

 usually at intervals of 5 to 10 years, each helping in the development 

 of the final stand. The purpose of thinning is very much the same 

 as that of the farmer in chopping his cotton or corn, namely, to 

 give the remaining plants proper growing space and to secure 

 the largest amount of the desired product. Trees growing wide 

 apart in understocked stands may not need more than one thinning 

 or they may not need any. If young longleaf stands contain unde- 

 sirable kinds of trees, such as slow-growing, wide-spreading gums 



