242 TIMBER AND SOME OF ITS DISEASES [chap. 



over large areas, the Peziza was also brought with 

 it ; but it will be clear from the foregoing discussion 

 that the climatic conditions were now proportionally 

 raised in favour of the fungus, and lowered to the 

 disadvantage of the larch. Plantations in damp 

 valleys, or in the neighbourhood of the sea, or of 

 large lakes, were especially calculated to suffer from 

 frost, and the damp air favoured the propagation 

 of the fungus, and the disease tended to become 

 epidemic. The enormous traffic in larch plants also 

 shows how man too did his share in spreading the 

 epidemic ; and in fact the whole story of the larch- 

 disease is of peculiar interest biologically, as illus- 

 trating the risks we run every day in tiusting to 

 the chapter of accidents to see us safely through any 

 planting undertaking, no matter how great the stake 

 at issue, or how ruthless the interference with those 

 complex biological and physical conditions which 

 always play such an important part in keeping the 

 balance in the struggle for existence between all 

 organisms living together. 



Let us now very shortly see what are the chief 

 lessons taught us by the bitter and costly experience 

 which the larch-disease brought to foresters. It is 

 evident that the larch should not be planted at all 

 in low-lying situations exposed to late frosts ; and 



