262 Studies in Forestry [CHAP. xn. 



for timber throughout the civilized world are steadily increas- 

 ing annually; while at the same time the total area under 

 forests is being reduced. More discrimination in the forma- 

 tion and the treatment of crops should, therefore, be exercised 

 generally than has hitherto been the case even in those coun- 

 tries that are furthest advanced in the art of forestry, and in 

 all scientific knowledge pertaining to Sylviculture. 



II. Minor Climatic Influences affected by the nature 

 of trie Treatment accorded to the Timber Crops. 



Whilst influences regulating the productivity of large neigh- 

 bouring tracts of agricultural land can be affected beneficially 

 by the formation of extensive woodlands throughout districts 

 in which the annual rainfall is less than 40 inches l , and can 

 also be prejudicially altered through great total clearances of 

 forest growth, yet even on a very much smaller scale such 

 local climatic effects as early and late frosts are to a certain 

 extent within our control. Just as, in the case of coniferous 

 crops, the annual falls should, for the purpose of protection 

 against wind, succeed each other in the opposite direction to 

 the prevailing or most dangerous winds, so also in undulating 

 tracts and uplands, indented with coombs likely to collect the 

 cold, heavy air at night, consideration should be given to the 

 regeneration or the planting up of the endangered tracts first 

 of all, before similar operations are carried out round about 

 them. If their planting or natural reproduction be left till 

 that of the surrounding land is completed, then, when the 

 young crops on these have reached the thicket stage of 

 growth, the circulation of the cold night air becomes impeded ; 

 hence there is danger not only of the plants put out being killed 

 off, but also of these spots becoming frost-holes exceedingly 

 difficult to plant up again with any of the less hardy species 



1 Endres, article Forslen in the Handivorterbuck der Staatsivissen- 

 schaften, Jena, 1892, vol. iii. p. 607. 



