236 Forestry Quarterly. 



Mr. Raphael Zon adds the following notes to the above state- 

 ment : 



In Europe, Pinus cembra Stone Pine, is the only representative 

 of the group of five-needled pines to which our white pines belong. 

 Pinus cembra has occasionally been found to be affected with the 

 blister disease, but within the large region of its natural distribu- 

 tion (Switzerland, Tyrol, and the Carpathians) no fructification 

 of the fungus has ever been observed. Only in the Ural Moun- 

 tains of Russia, where the Stone Pine is also a native tree, does 

 the fungus occasionally produce spores. This fact would indicate 

 that Pinus cembra is so resistant to the attacks of the rust that, 

 although the fungus can gain an entrance into its bark, it only 

 seldom reaches the spore-producing stage. Until the introduction 

 of the American white pines into Europe, this rust was not, there- 

 fore, considered of great danger. As soon, however, as the 

 American white pines were introduced and planted on a somewhat 

 extensive scale, the fungus found more favorable conditions for 

 its work, which is only another demonstration of what usually 

 happens when a certain disease comes in contact with new victims 

 which have not had time to become resistant to its attacks. White 

 pine rust, which could do but littl harm to Pinus cembra, proved 

 extremely fatal to Pinus strobus and Pinus monticola. Its attacks 

 are especially destructive to young trees. Old trees, protected 

 with thick bark, through which the fungus cannot enter, are more 

 resistant. In the case of old trees, the fungus attacks, therefore, 

 chiefly the tops of the trees and the younger branches. The young 

 seedlings, however, are attacked both through the stem and 

 branch, and therefore are killed off entirely. 



In Europe, according to Prof. Somerville, the disease is so 

 much on the increase that the outlook in that country for Pinus 

 strobus and other five-needled American pines is almost hopeless. 

 There are estates in Britain, like Murthly in Perthshire and 

 Woburn in Bedfordshire, where hardly a living young Pinus 

 strobus or Pinus monticola is left. The disease has played havoc 

 also with 'the white pine in the Crown woods near Ascot and 

 Windsor. 



In Denmark and in some places in Russia, as near Moscow, for 

 instance, the raising of white pine had to be given up entirely on 

 account of this rust. 



