122 BRITISH FOREST TREES 



shown by the yield tables of the Baden forest department, 

 although for the Black Forest Schuberg gives 11,600 to 

 14,500 cubic feet per acre for average soils and situations, 

 and up to 16,820 cubic feet for the best localities. 



With its strong recuperative power, silver fir suffers little 

 when branches are removed, either for decreasing the shade 

 cast, or for the production of large clean boles ; this opera- 

 tion is best conducted from the middle of August till October, 

 and by means of the saw. With its naturally dense habit, thin- 

 nings of this species should be on the whole light, until the 

 tree-forest stage of growth has been reached, w r hen they are 

 made somewhat heavier in order to stimulate the trees to 

 rapid growth in girth, except on exposures liable to heavy 

 falls of snow. 



Pure Forests of Silver Fir. No other species of forest 

 tree has so slow a development during the youthful period 

 as the silver fir, for its growth is at first in breadth rather than 

 in height, no matter whether naturally or artificially repro- 

 duced from seed or by means of planting ; it is a peculiarity 

 of its growth that there is generally one very long side-shoot, 

 probably provided by nature for the purpose of protecting 

 the soil-moisture. At ten years of age the silver fir is 

 usually no larger than a four-year-old spruce, but from about 

 ten years of age its growth in height in the open becomes 

 vigorous. The growth of the leading-shoot is not energetic 

 so long as the young crop stands under shade, which it often 

 has to do for twenty to thirty years and even longer, often 

 under dense shade from the parent standards. Its latent 

 energy and recuperative power are, however, such that 

 when the standards are removed, and a fuller measure of 

 exposure to light and air is available, an energetic growth in 

 height at once sets in on good soils, and is of long con- 

 tinuance. Seedlings grown under light shade from the 

 side or from above, and plantations in the open, begin 



