174 Proceedings of the Royal Physical Society. 



growth, or in any way diseased, unless pinched with hunger. 

 The bark, on being peeled off the pine-tree, does not again 

 close up, nor the wound heal as in hardwoods, in consequence 

 of which the sap, though allowed to ascend in the inner layers 

 of the wood, and thus reach the extreme top of the tree, is 

 nevertheless entirely obstructed in its descent, hence, that 

 portion of the tree below where the bark is peeled off, from 

 that time ceases to enlarge, except what is elaborated by the 

 few remaining branches below the wounded part. Though 

 the Scotch pine is undoubtedly the squirrel's favourite food, 

 yet in dry warm seasons it attacks indiscriminately the larch, 

 silver fir, spruce, and even poplars. The greatest amount of 

 damage done to trees is by peeling off the bark during spring 

 and early in summer, but in districts where the pine sows 

 itself, the loss sustained by the squirrel devouring the seed is 

 very considerable. The squirrel also destroys the young 

 shoots, which causes double tops on trees. . . . When 

 we consider the enormous amount of propert}^ annually 

 destroyed in Britain by squirrels, and the rapidity with which 

 they are increasing in numbers, it is certainly the interest and 

 duty of every proprietor of woods in Scotland to adopt means 

 for their extirpation." 



So much for Mr Michie's report, which may be taken as 

 fully illustrating in a general way the damage done. 



I have not obtained many actual estimates of damages done 

 on different estates simply because of the difficulty of making 

 such calculations, but the following is one I have received 

 from a forester of experience — Mr T. Milne, Forest of Glen 

 Tanar, Aberdeenshire. He writes to me as follows : " In 

 1874, the year in which we commenced to kill them, I con- 

 sidered that they destroyed 1000 trees. I would put it 

 down at a loss of £500 upon the woods of Glen Tanar." Mr 

 Milne then adds : " About 1000 squirrels have been killed 

 from 1874 until now — 1879." It may be imagined what 

 destruction must have taken place upon the Cawdor estates, 

 where as many as 1100 or 1200 have been killed in one 

 season, and where 14,123 were killed and paid for during 

 seventeen years. 



Adjoined is a list of the squirrels killed and paid for on the 



