1 82 Studies in Forestry [CHAP. ix. 



situation, and most likely to be in accordance with the wishes 

 of the proprietor in regard to the ultimate form of the crop. 



It also, however, not uncommonly occurs that the general 

 development of the young crop is somewhat backward, in 

 which case it may be necessary to stimulate its energy by the 

 introduction, temporarily, of quick-growing and lightly-foliaged 

 species, not apt to cast any heavy shade around them. In 

 general the special trees chosen for performing this duty are 

 again Scots Pine, Larch, and Birch, on ordinary classes of soil, 

 or Aspen, Willow, and White Alder, on land of a moister 

 description. By planting single rows of these trees at good 

 distances apart, very stimulating effects can be attained in 

 backward growth of young crops of Oak, Beech, Spruce, and 

 Silver Fir. As, however, this measure is temporary only, and 

 not permanent, these rows of supplementary nurses should 

 be gradually removed wherever, and whenever, the growth 

 of the principal genera forming the crop permits of this 

 being done. 



When once the normal density of canopy has been attained, 

 the manner in which the different operations of tending are 

 carried out in thickets of sapling growth, in young pole-forests, 

 or in tree-forests, has unmistakable influence on the imme- 

 diately subsequent development, as well as on the quantity, the 

 quality, and the financial value, of the future mature timber-crop. 

 These operations are of three distinct kinds, viz. : 



1. Weedings and clearings, including all operations involv- 

 ing an outlay which is not covered by the amount realizable 

 for the disposal of the material cut out. 



2. Thinnings, when the costs of the removal of the super- 

 fluous or undesirable poles or trees are covered, or more than 

 covered, by their sale. 



3. Partial clearances, carried out in tree-forest, after the 

 chief growth in height has been completed, with a view to 

 the more rapid development of large-girthed, full-wooded 



