GENERAL SUMMARY 183 



The bulky literature of the larch canker is almost entirely 

 the product of predispositioni.sts. About ten papers or 

 notes have been published in English on larch canker for 

 every one on heart-rot or the honey fungus, though the 

 latter diseases are very nearly as destructive as canker, and 

 the honey fungus, when the catliolicity of its taste in forest 

 trees is taken into account, is probably by far the most 

 destructive of all forest pests. The explanation of this 

 anomaly appears to be that many foresters will dilate on 

 the general sylvicultural conditions which make foi" the health 

 or sickness of a tree, whereas few are prepared to discuss 

 the more directly pathological factors which control attack 

 by a fungus which is just as prepared to parasitize healthy 

 trees as sickly ones. We will follow this bent and consider 

 first the general sylvicultural requirements of the tree. 



In the literature of larch culture with relation to canker, 

 great stress has been laid on the alpine habit of the tree, 

 which is repeatedly dragged in to explain failures of cultiva- 

 tion at lower elevations. Cieslar (1904), in a reasoned paper, 

 shows that too much importance has been attached to this 

 feature. In the Alps the present natural distribution of 

 the tree is confined to high altitudes, but in Silesia it comes 

 down to ],000 ft., and near Sokol it grows naturally and 

 healthilv, Avith sih^er fir, oak, &c., at an altitude of 600 to 

 800 ft. Probably in the lowlands between the Carpathians 

 and Russian Poland the larch has only been destroyed by 

 cultivation, and in earlier days the alpine nature of its 

 distribution may have been much less clearly marked. 

 There are, also, many lowland places where cultivated lai'cli 

 grows extremely well, and in many parts of its natural home 

 canker is very prevalent. 



Be this as it may, the larch has certain alpine charac- 

 teristics which must be taken into account in cultivation. 

 Chief of these are its faculty for bearing extreme cold in the 

 wdnter and its susceptibility to spring frosts. Alpine plants 

 have to contend with a short growing season and waste no 

 time in getting about summer work as soon as the snows 

 melt. On this account the bursting of the buds is generally 



