HOW TO GROW GOOD TIMBER. 



275 



The green sand surrounding the forest is mostly 

 devoted to the growth of larch or spruce, the thin- 

 nings of which are used for hop-poles and the 

 larger trees are left as timber-belts ; whilst the beech 

 will be found to favour the chalk. Hops and other 

 cultivated plants flourish according to geological 

 position. 



That the geology of a district affects vegetation 

 mainly, according to the mechanical and chemical 

 structure of its individual rocks and the climate in 

 which they are situate, is quite true; and yet the 

 following table will show that different formations 

 favour the growth of trees upon other conditions than 

 those named. 



Choosing figures to represent relative values, the 



annexed table is intended to show the amount of 

 influence exercised by certain geological rocks in the 

 growth of different fruit and forest trees met with in 

 England. 



These figures may serve to express- 



■although 



