74 A MANUAL OF FORESTRY. 



4. Age and Size of Plants. 



Plants aged from a few weeks up to ten and more 

 years may be planted out ; in fact the age is only 

 limited by the size and weight of the trees, and the 

 mechanical appliances available for the transfer. In 

 Sylviculture only young plants under ten years of age 

 need be considered. It may be said, as a general rule, 

 that young plants are best, because the operation of 

 planting is cheaper ; the plants survive more easily the 

 interruption of growth involved in the change, and they 

 adapt themselves more readily to new conditions. The 

 best age for planting out depends on the species and 

 locality. Quick-growing species can be planted out 

 earlier than slow-growing ones. Some tropical species 

 grow so quickly that the most suitable age for trans- 

 planting amounts to only a few weeks. In the temperate 

 climate of Europe yearlings are only exceptionally 

 planted out, as they are still too soft and have in- 

 complete root systems. In the great majority of cases 

 plants from two to four years old are used, while older 

 plants are indicated only in the case of a few species, or 

 where trees of some height are required, as in pastures ; 

 in frost localities ; for filling up blanks in already formed 

 plantations ; to become the underwood in coppice with 

 standards ; to enable one species to hold its own against 

 another of quicker growth ; for avenues ; &c. 



5. Season for Planting. 



The planting out is, after all, a violent operation, and 

 is generally accompanied by more or less injury to the 



