FOREST PROTECTION 131 



Frost may be invited on purpose to check a less 

 desirable species in mixture with a hardier 

 and more desirable species. 



C. Frost is Injurious 



BY LIFTING (UPROOTING) SEEDLINGS IN NURSERIES AND PLANTATIONS. 



Subject to damage are 



Flat rooted species growing slowly in early youth, notably 



conifers (yellow pine yearlings, white pine yearlings, 



spruce, hemlock); 

 Moist localities and loose soil; 

 East exposures, and notably steep east aspects. 



(a) Remedial measures are: 



Pressing seedlings back, soon after accident. 



(b) Restrictive measures are: 



1. In nurseries: 



Drainage by deep paths (middlings) between the 



beds; 

 Proper aeration of soil; 

 Seedbeds planted broadcast; 

 Strong seedlings, and long roots; 

 Shading beds, and covering space between the 



rows of plants; 

 No weeding in early fall. 



2. In plantations: 



Planting on reversed sods; 

 Mound planting; 



Planting three year-olds (two year old trans- 

 plants in case of yellow pine); 

 Planting ball plants; 

 Planting under shelter overhead. 



D. Frost is Injurious 



BY CAUSING FROST CRACKS 



in hardwoods only, notably in case of injured trees and of 



species having strong medullary rays. 

 Insect disease and fungus disease follow in the cracks. 

 Remedy: Timely thinning or improvement cutting. 



Cracks occur, notably, 



along lower part of bole; 

 on standards over coppice; 

 on south side of trees; 

 on medium sized trees (lJ^'-3'). 

 in moist localities. 



