26 BULLETIN 154, U. S. DEPARTMENT OF AGRICULTURE. 



trees were killed outright, while even those lodgepoles which had 

 their leaves killed retained their buds and put out new leaves the 

 following spring. Lodgepole saplings affected in 1909 now present 

 a peculiar banded appearance, that part of the stem which was 

 above the snow at the time of the injury being bare of leaves, while 

 that part below it. which was covered by snow, and that part above 

 it, which has grown since, are green. 



The red belt injury has sometimes been confused with damage 

 from smelter fumes, but its nature is entirely different. (PI. V, 

 fig. 2.) Trees killed by the former die quickly as compared with 

 those killed by the fumes. "Weather-damaged trees which have 

 recovered show a quick resumption of normal growth rate and a 

 general healthy appearance, a marked contrast to the trees suffering 

 from the smoke fumes. 



ANIMALS. 



Porcupines damage lodgepole to some extent by gnawing the bark 

 in order to get at the tender cambium. They confine their efforts 

 chiefly to young or middle-aged trees, though trees as large as 18 

 inches in diameter have been found completely girdled. Usually 

 the bark is gnawed near the base of the tree, but occasionally animals 

 work in the tops, as high as 50 or 60 feet from the ground, causing 

 the trees to become stag-headed. Small branches are sometimes 

 girdled near their junction with the main stem. Sometimes the 

 attack may result in a beneficial thinning in an overdense stand, 

 but porcupines have done considerable damage to trees on the 

 Eoutt Xational Forest, Colo., where more than half of the trees 

 on areas from one to several acres have been girdled, and in several 

 localities on the Bonneville Xational Forest, Wyo., where 25 per 

 cent of the trees have been injured. 



Rabbits often bite through the main stem of young seedlings, 

 particularly the slender ones in overdense stands. Squirrels may 

 cause a slight decrease in the rate of growth by biting off a number 

 of the cone-bearing twigs. They also eat considerable quantities of 

 seed, the result of which may be harmful in places where reproduc- 

 tion is not up to the required density. Sheep grazing unrestricted 

 may damage seedlings and very young growth by trampling. 



ASSOCIATED SPECIES. 



Over most of its range lodgepole pine occurs in almost pure stands. 

 Other species, however, often grow in mixture with it, particularly 

 at the upper and lower altituclinal limits of the lodgepole zone. At 

 the lower limit its chief associate is Douglas fir, which tends to take 

 possession of areas too dry for lodgepole. Fir reproduction often 

 occurs under the latter, and many areas now covered with lodgepole 



