THE GENUS DENDROCTONUS. 69 



whenever small patches of infested timber are found it should serve to 

 keep this enemy under complete control. 



Summer operations in the felling and barking of infested trees are 

 not to be recommended except in special cases, when, for example, 

 it is desirable under a clear-cutting system to include the healthy 

 timber with the infested, or when practically all of the timber over a 

 large area is infested during the spring and summer; otherwise, if only 

 the infested trees are cut and healthy ones left, the felled and barked 

 trees attract the flying beetles to the locality, and thus the death of a 

 large amount of the surrounding healthy timber results. 



If it is desirable to make clear cuttings during the summer, to 

 include small or large areas of infested timber, it should be done 

 during the principal periods of larval development — August and 

 September in the northern section, and from July to October in the 

 southern section. 



Whenever it is desirable to protect a small or large estate, or a 

 particularly valuable section of the forest surrounded by forested areas 

 in which the infested timber can not or will not be cut and barked, 

 the greatest precautions should be taken to prevent the cutting of 

 pine timber for any purpose during the spring, summer, and early 

 fall. The only exception would be lightning-struck or storm-broken 

 and felled trees, which, under certain conditions, should be cut and 

 removed, or burned with the tops, if possible, the next day after the 

 injury occurs. If the logs are removed the tops should be burned 

 over the stumps. 



If pine cord wood is cut during the summer, it should be done under 

 the clear-cutting system and confined to a section of the forest away 

 from the more valuable timber which it is desirable to protect from 

 insect attack. Cord wood, new lumber, etc., should never be piled 

 in proximity to living pine trees, neither should building operations 

 involving the use of new pine lumber or fresh paint be conducted 

 during the summer in or near a desirable grove of pineor spruce. All 

 of the above relates especially to sections where the heetle is present 

 in the surrounding forest. 



Some experiments conducted by Mr. W. F. Fiske, while working on 

 forest insects, indicate that if the infested trees are felled in November 

 and December and left flat on the ground and the upper side of the 

 trunk is scored or blazed so as to facilitate the entrance of water from 

 rains and melting snows, the broods will be killed by the abnormal 

 wet condition of the inner bark. 



When the infested timber is near streams or ponds the broods may 

 be destroyed by placing the unbarked trunks or logs in the water, pro- 

 vided the work is done before the broods begin to emerge. 



