OLEORESIK PRODUCTION. 41 



This production of gum by the tree is greatly increased as a result of 

 the stimulation of the wound or face cut. 



The institution of cupping, in place of boxing, made it possible to 

 eliminate the unnecessary injury to the tree caused by cutting the 

 box, and hence was a marked advance in the direction of improved 

 operation. 



The proper placing of faces with reference to the size and confor- 

 mation of the tree, and the maintenance of bark bars of sufficient 

 width between faces, are matters of fundamental importance, which 

 too often are neglected in practice. These matters if not cared for 

 involve waste and loss throughout the operation. 



The fact that it is unprofitable to turpentine too small trees, at 

 least by present commercial methods, has been demonstrated beyond 

 question. 



The practice of cutting a streak in advance of the regular season's 

 chipping on a virgin or first year operation appears to be productive 

 of an increased early yield, which is of practical importance. This 

 effect, as has been clearly shown, is not produced by the induced resin 

 passages, formed at once as the immediate result of the streak, but 

 presumably is due to the wound stimulus given to the resiniferous 

 tissue already present. 



The following effects of turpentining on the structure of the wood 

 have been pointed out : 43 



The structure of the annual rings of the wood formed before tur- 

 pentining was not found to be visibly affected as a result of the tur- 

 pentining, although the activities and responses of the living paren- 

 chyma cells in the outer layers of the sapwood already present in the 

 immediate vicinity of the wound were undoubtedly stimulated by it. 

 It was demonstrated that the resin passages of a considerable number 

 of these outer sapwood rings contributed a very significant portion 

 of the yield of oleoresin. 



The structure of the wood produced after wounding was con- 

 siderably modified, especially in the region immediately above the 

 face. The effect in a tangential or circumferential direction was 

 relatively slight, being hardly noticeable at a distance of 2 or 3 inches 

 to the side of the wound. In all material the number of resin pas- 

 sages formed was greatly increased. The resin passages were formed 

 Burlier in the ring than normally. They varied from about the same 

 diameter as thai of the normal resin passages to rarely larger and 

 frequently smaller diameter8< The response to the wound stimulus, 

 particularly in respect to the increased number of resin passages 

 formed, was ojbaenved to !«• greats I within about I foot above the 



.iIho 0<Try, K., " Proper Method! oi 'Turpentining," Bel. Am. Sup. 2178, Sept. 15, 

 1917 ; and Oerry, E., " Production of Crude (ium by the 1'ine Troe," Naval Btofctt, p. 147, 

 1921. 



