94 BRITISH FOREST TREES 



passage. According to Burckhardt, 1 in the Hanoverian 

 portion of the Harz mountains, aggregating 134,350 

 acres, of which four-fifths, or 107,480 acres, are under 

 spruce, during the present century (up till 1870) over 

 two millions of mature spruce were thrown by wind, or the 

 equivalent to full crops on about 10,500 acres, nearly 

 8 per cent, of the total area. He also estimates that 

 wind and snow combined have during the present century 

 destroyed at least four millions of stems in the tree-forest 

 stage of growth, without including those that have been 

 merely damaged by wind or snow, and have consequently 

 fallen victims afterwards to bark-beetles, which first of all 

 attack the sickly stems, breed there, and then attack sound 

 and healthy trees, unless all unsound individuals are removed. 



Pure Forests of Spruce. Localities with a short period of 

 vegetation being the natural home of spruce, its cultivation 

 in pure forests in Scotland would seem advisable wherever 

 the upper soil has the requisite moisture. In the generally 

 damp climate of both the lowlands and highlands of 

 Scotland with their comparatively short summer, the factors 

 are given which hold out promise of the normal development 

 of spruce, although its growth may perhaps not be so rapid 

 as in warmer southern localities. At higher elevations or 

 in the far north it takes perhaps a hundred to a hundred 

 and twenty years to attain the same average dimensions in 

 pure spruce forests that can be arrived at in lower or 

 warmer localities in eighty to a hundred years, but this 

 shortening is to a great extent counterbalanced by the better 

 quality of the timber produced. 



Tempted by the remunerative promises held out, spruce 

 forests have often been formed on heavy loams and 



1 Siien und Pflanzen, 1880, p. 329. The introduction of the silver 

 fir and the re-introduction of beech into these spruce forests has been 

 occupying the attention of foresters there for many years past. 



