ii8 BRITISH FOREST TREES 



wings. As with the spruce, a good seed-year can generally be 

 foretold by the flowering shoots being bitten off and thrown 

 down by squirrels. The cones ripen in the September or 

 October after flowering, and the seed is shed at once in the 

 autumn, so that arrangements for collection must be made 

 early. 



Liability to Suffer from External Dangers. In comparison 

 with spruce, the silver fir is less exposed to most kinds of 

 danger. Deep-rooted, however, though it be, it is still 

 liable to be thrown by the wind ; but as each individual tree 

 has its own well-developed root-system, storms are seldom 

 able to make whole forests windfall, only the upper 

 portions of the stems being usually broken off, which 

 happens especially when the stems are attacked by canker- 

 ous fungous disease (/Ecidium elatinum). Injuries caused 

 by snow or ice are also, owing to the greater elasticity of the 

 branches, less wide-spread or serious than in the case of the 

 pine or the spruce, and the loss of a leading-shoot is soon 

 replaced by one of the side-branches assuming that function. 



As in the mountainous regions where the silver fir is 

 indigenous there is little or no variable spring weather, but 

 wintry conditions may be said to obtain till late in April or 

 even May, and then a sudden change, extending often over 

 only a few days, takes place to summer-like heat, the danger 

 from late frosts in spring or early frosts in autumn is not 

 great ; and it is further lessened by the usual form of natural 

 reproduction carried out under the shelter of the parent 

 trees. It is greater in localities at lower elevations, or near 

 its northern limit of indigenous growth, where the leading- 

 shoot is apt to be killed by frost during the youthful period 

 before it can raise its head out of the coldest, damp layers 

 of air near the surface of the soil. 



Insect enemies also attack the silver fir less than other 

 conifers, and they do not in general commit the same 



