CLIMATE AND SOIL 25 



In all places where frosts are known to be bad. care should 

 be taken to plant frost-hardy species, of which perhaps the 

 pines, spruce, and hornbeam are the best, the latter especially 

 being able to resist severe frosts. Larch, though hardy, is 

 very liable to suffer from diseases in such places, and should 

 not be planted except as a temporary shelter for other trees. 

 The choice of species is greatly enlarged if there is an existing 

 wood on the spot, as the new crop can be planted under the 

 shelter of the old wood, which will considerably reduce the 

 danger. In this case the effect of the shade thrown by the 

 older crop must be carefully considered, as pointed out a few 

 pages further on, and the overhead cover must be reduced to 

 the degree which will suit the species to be planted. It is not 

 only directly under the shade of the older trees that the frost 

 is reduced ; in fact, a very thin overwood of scattered trees 

 will very materially reduce the damage done to young trees 

 planted under and between them. 



If no older crop exists, and it is desired to plant a tender 

 species, it will be necessary to start operations by planting 

 a thin wood of birch or larch, and to introduce the new crop 

 when these are tall enough to give some shelter. The birch 

 or larch should be cut out when the young crop is well estab- 

 lished and out of danger. 



Put shortly, the following measures may be taken to protect 

 plants from frost : 



(a) In a forest nursery. 



1. Form nurseries on north and north-west aspects. 



2. Do not sow seed before the first of May, and cover 

 it well. 



3. Cover the seed beds with dead leaves in autumn, or 

 with branches of trees in spring, or place mats over the seed 

 beds, on short supports, when a bad frost is expected. 



(b) In the forest. 



1. Drain wet places before planting. 



2. Plant tender species under a light shelter wood. 



