Birds and Forest Vegetation 499 



injured specimens ranged in diameter from about Y\ of an inch to 

 i x /2 inches, and each specimen secured represented a single tree and 

 not branches or parts of trees. 



One dead tree (No. X) was an excellent example of severe 

 girdling. This tree was 1.25 inches in diameter and very 

 severe girdling extended over 27.5 inches of the stem (figure 

 149a). The holes were so numerous that long vertical strips of 

 the bark had been removed, or had curled and fallen off as the 

 bark dried out. It was one of the most extensive and thorough 

 injuries observed on an aspen. This tree was probably killed early 

 in the season of 191 5. Complete girdling (No. 5), largely con- 

 centrated in a seven-inch belt, is well shown in figure 149b, and a 

 similar (No. 12) but even more severe attack is shown in figure 

 150c. 



A dead tree was found which had been girdled in a narrower 

 belt, of about 8 inches in length. In some cases there had been 

 considerable healing (No. 10) and the stem had a knotted or 

 gnarled appearance (figure i5od). In the case of some specimens 

 (No. X, figure 149a, and No. 12, figure 150c), the injury was 

 so extensive that death was rather sudden, for the burrows were 

 fresh and clean cut in appearance, as if no progress had been made 

 toward healing at the time of death. One small tree, yi inch 

 in diameter (No. 4), showed injury of similar freshness, for the 

 dead leaves were still on, except a very few, which were still green 

 in part (figure i5oe). The wounds on this extended over about 

 14 inches of the stem, and were unusual in that they were very 

 irregular in position, both horizontally and vertically. 



Another series of trees had been girdled in varying degrees (Nos. 

 2. 8, 9, 9a, 9b, 9c, 13, 14, 15, 16 and 17) but were alive. A 

 tree about an inch in diameter (No. 9a) had been severely wounded 

 in patches, for 35 inches along the stem. The gnarled areas are 

 shown in figure 149c. Some of the old wounds are peculiar in 

 that they give the bark the appearance of an irregular flattened 

 or sunken blister, with the central perforation and an elevated rim. 

 These show that irregular areas of about half an inch by three- 

 quarters were killed by the perforation ; six of these blisters were 

 - found on this stem. Nos. 8 and 9 each showed one of these 

 blisters, and No. 9b showed many of such patches. One (No. 

 9b) had been severely girdled several years ago and gnarled 

 wounds had developed ; it seems to have suffered two or more later 

 attacks, one in the vicinity of the old wound and others near the 

 base of the tree (figure I49d). The main later attack completely 

 encircled the trunk and yet the tree had apparently recovered, or 

 at least looked healthy. 



Two live trees had been injured recently (Nos. 13 and 15) so 

 that they might not have revived, as the girdling was very com- 

 plete and concentrated. One (No. 15) showed the blister effect, 

 another (No. 14) had been severelv girdled (figure i5od) ; con- 

 siderable progress had been made in healing, as it also had on 

 a less injured one (No. 16). One tree (No. 17) was found dying, 



