568 Forestry Quarterly 



ment to check it in many regions where the parasites most aboimd , 

 but very often the method of cutting is such as to directly insure 

 the propagation of the parasites. I refer in the main to the 

 leaving of heavily infected trees on sales areas. Very often 

 such trees, although of merchantable size and which otherwise 

 would come under the cutting clause, are so seriously burled 

 and infiltrated with pitch that very little merchantable material 

 can be obtained from them and they are allowed to remain stand- 

 ing. This in itself is in direct opposition to the most fundamental 

 principles of forest sanitation which has for its object the preven- 

 tion of permanent injury to reproduction or to more mature forest 

 growth. The leaving of broomed, burled, and spike-topped mistle- 

 toe-infected trees would not in itself be so serious a matter, although 

 in many regions it involves the loss of large simis, but the ease 

 with which the reproduction is permanently infected from such 

 trees shows the necessity of their destruction. The fact that the 

 older infected trees introduce other factors of prime importance 

 in the deterioration of the stand is of additional concern. A 

 tree that can not eventually yield the best and largest amotmt of 

 material when growing on its normal site should not be allowed to 

 exist among its healthy neighbors. This is the principle of htmian 

 hygiene applied to forestry. Mistletoe-infected trees during the 

 years preceding and in the last stages of suppression are apt to be 

 carriers and distributors of serious wood-destroying fungi, result- 

 ing not only in the decay of the trees themselves, but transmitting 

 or maintaining these agents in the forest. Since in many cases 

 the groimd is extensively shaded by low, sprawling, mistletoe- 

 infected trees, air and light are excluded from an otherwise fertile 

 soil for young growth. The space occupied by such trees is 

 wholly wasted and the opportimity for the maximum yield for the 

 type is entirely lost. A more direct influence on the future of the 

 oncoming forest is the small size and poor quality of the seed pro- 

 duced by trees seriously suppressed by mistletoe. Considering the 

 trying conditions under which forest tree seed must at times ger- 

 minate and tmder which the young seedling must become estab- 

 lished, the best quality of seed is none too good. Add to this the 

 fact that mistletoe brooms and eventually the uninfected parts 

 of the tree cease altogether to produce seed, the practice of leav- 

 ing trees of this kind for seeding purposes is not good forestry. 

 This is all the more important when it is considered that such 



