64 TRANSACTIONS OF ROYAL SCOTTISH ARBOKICULTURAL SOCIETY. 



Immediately following this period, another beetle, the pine 

 beetle (species of genus Myelophilus), is very destructive. 

 This beetle breeds under the bark of dead and dying Scots 

 pine, then burrows in the living shoots of the trees ; these 

 break over, and the crown development is consequently interfered 

 with. Another and probably an even more serious enemy now 

 appears, viz. the squirrel. In England and those parts of 

 Scotland where there are many nut-bearing hardwoods, the 

 squirrel does not generally attack conifers, but in the absence 

 of such hardwoods, this animal does very great damage. 

 The squirrel tears off strips of bark from the stem in the lower 

 part of the crown in order to lick the sap. The tree is either 

 girdled and thus killed, or the stem dries and is easily broken 

 over by wind or snow. The author has seen large areas of 

 Scots pine, hundreds of acres in extent, where there was scarcely 

 a tree which had not been damaged in this way. When the 

 squirrels are very abundant, spruce and larch are similarly 

 attacked, but Scots pine is undoubtedly the favourite victim. 

 These are the most serious of the enemies of Scots pine, but by 

 no means the only ones. Unlike most other conifers, the pines 

 in woods having a complete canopy improve the soil, e.g. on 

 the sand-dunes of the Landes in the south of France. In the 

 course of one rotation a pure sand is frequently converted into 

 a black loam to a depth of 6 inches or more. This not only 

 increases the soil's fertility, but increases its power of retaining 

 water, a very important matter. The only disadvantage of the 

 humus thus formed is that it is slightly acid. 



Scots pine occupies an important place in the home timber 

 trade of this country, as up to the present it has been our 

 principal forest tree. It is converted into sleepers, boarding 

 of all sizes and for all uses, and pit-wood. As regards strength, 

 durability, and weight, it occupies a definite position, intermediate 

 between larch and spruce. 



It can be seen that the position of Scots pine in the future 

 development of forestry in this country requires careful con- 

 sideration. 



Experiments should be carried out to determine — 



i. How far other conifers can be profitably used to replace 

 Scots pine under conditions which have hitherto been 

 considered suitable for it but under which it has not 

 given satisfactory results. 



