THE LARCH IN GEltMAN FORESTS. 47 



VI. The Larch in German Fo7-esis. By Forstmeister 

 Franz Boden, 



I. The European Larch. 



In a long article published in the Forst- unci Jagclweseti of April 

 1901, Forstmeister Boden, of the Hanoverian State Forest Service, 

 gives his views regarding the grovi^ing of the European Larch in 

 Germany, ics attack by canker, and other matters. He maintains 

 that the fungoid diseases of the larch are, for the most part, 

 secondary phenomena, which make their appearance in localities 

 unfavourable to the growth of the tree; and in this view he claims 

 to receive support from certain scientific men. He contends that 

 the fungus {Peziza Willkornmii) cannot make good its attack by 

 infecting sound plant-tissues. The disease, he says, is not found 

 otherwise than on weak or decayed twigs and stems, never on those 

 of vigorous growth; but it develops on dead or nearly dead shoots, 

 and because the sap in them has ceased to How, its presence does not 

 there lead to the formation of a cankerous wound. The swellings 

 which accompany the disease on living stems or branches are due 

 to the action of the flowing sap, but the fungus is the cause of the 

 actual canker. The canker avoids vigorously -growing larches, but 

 successfully attacks trees "in their time of adversity," when their 

 energy of growth is weaker than its own. The author says that 

 the larch in Germany persistently remains for years in an enfeebled 

 condition, making short shoots, and that it then forms a perfect 

 Eldorado for Peziza. He quotes Hartig's statement that in summer 

 — that is, at the time of the trees' maximum seasonal development 

 — the fungus stands still in its growth. According to his own 

 observation, the activity of the fungus is certainly thus checked on 

 the green parts of the tree, this being due to the full flow of resin; 

 but he says that the growth of the fungus at this season goes on 

 with undiminished vigour on dead parts. 



In regard to crookedness of stem not due to the action of the 

 sap in a cankered tree, he attributes this defect mainly to wind. 

 In a sheltered plantation crookedness of stem appears only at 

 the margins of the crop, and is specially noticeable in the case of 

 isolated trees. On poor soils and exposed situations, however, 

 stems may be cankered and crooked; while a few hundred yards 

 ofi", on good soil, the stems remain uninjured and straight. There 



