228 Studies in Forestry [CHAP. x. 



application with the Spruce and the Silver Fir among shade- 

 bearing genera ; and as they show many points of similarity, 

 these two trees may be considered together. Where, however, 

 there is any likelihood of windfall or damage from storms, this 

 method is totally unsuited for the Spruce. 



Spruce and Silver Fir. The way towards partial clearance 

 should be paved by preliminary operations carried out about 

 the twenty-fifth to thirtieth year in such a manner as to let the 

 predominating poles have a clear space of 2 or z\ ft. around 

 the crowns. These favoured individuals should stand about 

 15 to 17 ft. apart, all the rest of the crop being thinned out in 

 the ordinary manner customary in pure forests without inter- 

 ruption of canopy. During the thirtieth to fiftieth year, when 

 the influence of this measure has made itself apparent in the 

 re-formation of close canopy, the main partial clearance takes 

 place in a somewhat similar manner. The stems between the 

 favoured individuals should be freely thinned so as to permit 

 of the formation of an undergrowth either naturally, or where 

 necessary artificially, wherever the minor portion of the crop 

 is of itself insufficient to protect the productive capacity of the 

 soil. When the favoured stems have at breast-height a girth 

 of about 36 to 40 inches, which they should attain between 

 the sixtieth to eightieth year, the marketable trees can then be 

 gradually cleared away on the same principle. 



Another method, practised in the neighbourhood of Salzburg 

 in Western Austria throughout mixed forests consisting of 

 Spruce, Silver Fir, and Beech, consists in carrying out the 

 thinnings once every ten years after the crop has attained thirty 

 years of age, and in making them heavier each time the opera- 

 tion is repeated, until the main partial clearance is made about 

 the sixtieth or seventieth year, leaving 120 to 160 stems per 

 acre, all of them conifers and in energetic growth. Under 

 such a crop natural reproduction can easily be effected, so that 

 about twenty years later the standard trees are of large market- 

 able dimensions, whilst the young growth may vary from 



