266 A MANUAL OF FORESTRY. 



than one-third of an inch, and they germinate, if sown 

 in spring, after 4 to 6 weeks. 



In nurseries a moist part should be chosen for the 

 seed beds ; at any rate they must be kept moist after 

 sowing. The seed is sown broadcast. When one year 

 old, the seedlings may be pricked out, and left one or 

 two years in the nursery lines. 



The planting is mostly done in pits. 



i. Tending. 



Alder does not require much tending. When quite 

 young it is liable to suffer from frost lifting, owing to 

 the moist condition of the soil where it is usually grown. 

 This can be prevented by covering the space between 

 the plants ; any plants actually lifted must be promptly 

 put back into the ground. 



Considerable danger may threaten Alder from the 

 drying up of the subsoil owing to a change in the level 

 of the ground water. Such danger must, as far as prac- 

 ticable, be avoided, by preventing the water from being 

 drained away. At the same time inundation may do 

 much damage, especially if it occurs after a wood has 

 been coppiced, and if the water covers the stools, or if 

 sheets of ice form over young plantations. 



Insects and fungi do little damage. The foliage of 

 Alder may be injured by Tortrix larv3, or by the plant- 

 beetles, Agelastica alni and Lina cenea, both uncommon 

 in England. The bark of young Alders is attacked by a 

 weevil, Cryptorrhynchns lapathi, which breeds in their 

 stems. Older trees are bored by the Cossidce and one 

 or two Sesias. 



