638 GEOLOGICAL SURVEY OF THE TEREITORIES. 



Allow me, sir, to tender my sincere thanks to yourself, Professor 

 Gardner, Mr. Stevenson, and, in fact, to all the members of the party, for 

 the cordial assistance rendered mo in the pursuit of my duties as natu- 

 ralist of your survey. 



I am, sir, very respectfully, your obedient servant, 



W. L. GAEPENTER, 

 Lieutenant, United States Army. 

 Dr. F. Y. Hayden, 



United States Geologist. 



DESTRUCTION OF PINE-TIMBER IN THE ROOKY 

 MOUNTAINS. • 



By Lieut. W. L. Carpenter, U. S. A. 



While attached to the United States geological survey for 187^, my 

 attention was attracted to a singular destruction of pine-timber in the 

 Rocky Mountains, in the Territory of Colorado, by some agency unknown 

 to myself. While personal observation satisfies me of the existence of 

 such a baneful influence, I can only hope that a description of its effects 

 will enable others to determine its cause, as my limited observation 

 does not permit me to arrive at any satisfactory conclusion concerning it. 



In the region of country lying between the eastern slope of the na- 

 tional range and the southern waters of the Colorado River, many pine- 

 trees may be noticed stripped of their bark in such a way as to cause 

 their decay. Sometimes the tree will be seen completely girdled, at 

 others only denuded of a small patch of bark, which does not seem to 

 affect its growth. The injury appears at any part of the trunk of the tree, 

 and may often be seen at a distance of forty feet from the ground, which 

 precludes the iJossibility of human agency. This fact was carefully veri- 

 fied, as it is well known that the Ute Indians strip the pine-trees of 

 bark in the spring of the year to obtain the pulpy substance next the 

 wood for food ; but the bark is by them always stripped off smoothly 

 in large i)ieces near the ground, and from trees in the vicinity of good 

 camping-places ; while the girdled trees referred to may be found in 

 the most inaccessible places, and often near timber-line. As far as 

 known, there is but one species, the yellow pine iPinus ponderosa), so 

 attacked; and although the white spruce and quaking-aspen are to 

 be found in the same vicinity, they never appeared to suffer. 



The injury first begins with a row of holes about one-fourth of an inch 

 in diameter at the surface of the bark, and terminates in a point at' the 

 wood. These holes are generally drilled in nearly parallel lines, per- 

 pendicularly and horizontally, then gradually enlarged, until finally they 

 connect with each other, and the tree appears entirely stripped of bark 

 for a vertical distance of two or three feet. 



A careful examination of these trees in their various stages of decay 

 was made for traces of insects, but nothing could be discovered whiqh 

 would lead one to suppose that it was their work. If attributable to 

 the ravages of coleopterous insects, such as the Giirculionidw and Ge- 

 rambycidce, those most destructive to vegetation, then the damage must 

 have occurred in some previous year extraordinarily productive of these 

 insects ; for although found there this season, they were quite rare. Nor 

 could any unusual signs of coleopterous larvae be found in the bark or 

 wood of these trees. It also seems imijrobable that such extensive dam- 

 age could have been inflicted bj birds of the Picidce family, noted for 



