62 BRITISH FOREST TREES 



become infected by Phytophthora omnivora. Red-rot l in 

 the timber is caused by Polyporus vaporarius and P. mollis. 



The above-mentioned insect enemies of the Scots pine 

 also endanger to a greater or less extent the well being of 

 the other species of pine black or Austrian, Cembran, 

 maritime, Weymouth, but their attacks are usually neither 

 so frequent nor so serious. A similar remark also obtains 

 with reference to the fungoid diseases. 



Accumulations of snow and ice on the branches, also heavy 

 storms of wind and rain, often cause much damage, as 

 during the sapling- and pole-stages of growth the wood of 

 the branches is very brittle. In spite of the thin crown of 

 foliage, on shallow-soiled, exposed localities the danger of 

 trees being thrown altogether (windfall} is greater than on 

 the sandy plains where the deep, strong tap-root lends 

 security to the stem. 



Very serious damage can be caused by forest fires in the 

 dry months of summer, especially when the thicket age has 

 not yet been passed ; no tree suffers so much from this 

 danger as the Scots pine, owing to its richness in resin. 

 Protected by its rough bark it is not after the twentieth year 

 liable to be much damaged by deer, but wounds occasioned 

 by red-deer stripping the bark with their teeth, both in 

 winter and summer, and rubbing the velvet from their 

 antlers in early summer, heal better than those inflicted on 



1 Hess, Der Forstschutz, 1890, vol. ii. p. 185, says : " Red-rot is 

 occasioned by the solution of cellulose in a decomposing ferment formed 

 in the protoplasm of the fungus and communicated by the mycelium to 

 the surrounding cells ; a resinous or tannic residuum is formed, which 

 in oxidizing assumes a reddish-brown appearance. In white-rot tru 

 ferment of the mycelium dissolves the lignine, and leaves the bright- 

 coloured cellulose untouched, hence the whitish colour of the diseased 

 wood." 



The details concerning insect enemies and fungoid diseases are 

 mainly drawn from Hess's Forstschutz, 2nd Edit., 1887 1890. 



