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JOURNAL OF FORESTRY 



It is to be noted in Table 1 that the killed trees were in close 

 proximity to brush, one-third being in open and the remainder in dense 

 brush. The same proportion holds true for those trees classed as 

 seriously damaged. On the other hand, 9 of the trees with slight in- 

 juries were in the brush and 8 in the open, and, of the trees with 

 no injury, m6re than twice as many were in the open as in the dense 

 brush. These data are summarized in Table 3. 



In general, the distance of the tree from an inhabited nest has 

 considerable bearing on the damage done. If a near-by tree stands in 

 the open, however, it is safer than if it were at a much greater dis- 

 tance, as the cover conditions are then the more important. Short 

 open spaces between dense patches of chaparral are no drawback, 

 but a wide open space in the cover is studiousily avoided. In brush 

 of fairly uniform density, the trees will suffer more severely than 

 those in open brush or in brush of a patchy character, and this work 

 is confined to that part of the tree which does not appear above the 

 crown cover unless the chaparral forms an understory to a higher 

 tree cover. It is probably due to this fact that this destructive activity 

 of the pack rat escaped notice for so long. 



The amount of work done on a single tree is astounding. The 

 most remarkable case which has come to my attention is a Jeffrey 

 pine 12 feet in height and bearing 480 scars visible on the surface. 

 This tree, which was 30 years old, had 17 branches on it below the 

 point at which the needles were persistent, and of these 16 had been 

 injured in one way or another, while 24 of the twigs had been cut off. 

 There were 445 scars on these branches, each scar being separate and 

 distinct. On the main stem of the tree there were 35 abrasions, some 

 of the bark being removed in a broad strip 6 inches long, while at 8 

 feet from the ground the tree was almost completely girdled for nearly 

 a foot, two of the larger lower branches being killed in this manner. 



