DANGEROUS FOREST DISEASES IN AUSTRIA 



Kurt Lohwag 



Professor of Forest Pathology, 



Hochschule fur Bodenkultur, 



Vienna, Austria 



Introduction 



The economic and international importance of forest diseases must 

 be judged from two different points of view. 



On the one hand, there are diseases which attack individual trees 

 and cause stationary damage. This is accepted as a fact. Should 

 these diseases be widespread in neighboring countries too, it need not 

 be supposed that the significance of the diseases has suddenly in- 

 creased. If, however, neighboring countries are completely free of 

 these diseases and more favorable conditions for the diseases arise, 

 then the situation is quite different. 



On the other hand, there are forest diseases in every country which 

 are well known but largely disregarded for two reasons — either (a) 

 their economic importance is too slight or (b) the aggressiveness of 

 the fungi is of no importance. Diseases of this kind, however, may 

 become very dangerous if a sudden aggressive mutation takes place 

 in the fungus. 



In order to demonstrate conditions in Austria, it is necessary first 

 of all to give a survey of the distribution of individual trees in this 

 country. 



Conifers : Hectare Percent 



spruce 1,824,000 58.1 



white pine 305,000 9.7 



fir 220,000 7.0 



larch 211,000 6.7 



Pinus montana 41,000 1.3 



P. nigra 31,000 1.0 



P.cembra 16,000 0.5 



84. 3 

 Broad-leaved trees: 



beech 300,000 9.6 



oak 65,000 2.1 



alder 31,000 1.0 



hornbeam 31,000 1.0 



poplar and willow 29,000 0.9 



ash 12,000 0.4 



maple 11,000 0.3 



other broad-leaved trees 11, 000 0. 4 



15.7 

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