STOCKING THE GEOUND 111 



Disadvantages of Pure Plantations. 



Crops of pure light-foliaged trees admit too much 

 light, and allow the soil to deteriorate. 



Danger from fire is greater in pure coniferous woods 

 than where there is an admixture of hardwoods, and the 

 risk of damage by insects or fungi is greatly increased. 



Advantages of Mixed Plantations. 



The soil is protected and improved when soil-improvers 

 are mixed with light-foliaged trees. 



The side-branches of a light-foliaged main crop ' are 

 rubbed off better if shade-bearers are mixed with them 

 than in pure light-foliaged woods, and the timber is 

 consequently of higher value. 



The more expensive trees can be planted at wider 

 intervals, thereby reducing initial expense, and the inter- 

 vening spaces filled up with cheaper varieties, which 

 may be more valuable as thinnings at an early age than 

 those of the main crop. 



If the principal species fails, there will be another left 

 to take its place as the final crop. 



Deeper-rooted or more hardy species can be planted 

 as nurses to protect the main crop against frost or storms, 

 and hardwoods introduced into coniferous plantations as 

 a protection against fire. 



Disadvantages of Mixed Plantations. 



They are most difficult to manage. The different 

 species seldom reach maturity at the same time. 



