98 VEGETABLE SUBSTANCES. 



track, the bark has been free from these parasites. 

 Further, after the trees have attained sufficient 

 size to shelter the land, the moss has disappeared 

 from it, and the soil has become fit for the pro- 

 duction of valuable crops. Nor is it on trees alone that 

 this effect of winds, from cold and watery tracks, may 

 be perceived; for those sides of ancient and elevated 

 buildings which are opposed to them, are incrusted 

 with moss and lichen, while the other sides are com- 

 paratively clean. To any one who has paid much 

 attention to the more sterile districts of the country, 

 it is matter of every-day notice, that nothing tends so 

 much to confine within bounds the plants which are 

 hostile to the grasses and cultivated crops, as timber; 

 and this being the case, it follows that the means of 

 procuring an instantaneous shelter of grown timber 

 are, at the same time, the surest means of procuring, 

 comparatively, instantaneous fertility. In very many 

 instances that we have seen, the land, when not shel- 

 tered by timber, has returned to its original sterility, 

 whenever it has been allowed to lie in grass; but 

 when so sheltered, the pastures have retained their 

 greenness for years, and, instead of being deteriorated, 

 have been improved by remaining for a few years out 

 of tillage. 



The transplantation of grown timber-trees appears, 

 indeed, to be the only way, by which shelter can be 

 restored to cold, bleak, and exposed districts. The 

 remains of large trees, which are found in the mosses 

 and bogs of such districts, prove that once both the 

 soil and climate have been adapted to the production 

 of wood. This is true not only of those countries 

 where timber is still to be found in warm and shel- 

 tered places, but in those dreary climes where now 

 hardly a shrub is to be found, and where, although 

 young timber be planted, it will not grow, as in the 



