148 



TREES IN" WINTER 



affected in this way usually leaf out again the following spring and 

 show no ill effects. 



The most serious fungus pest of shade trees in the northeastern 

 states is the Chestnut-hark disease. Enormous tracts of chestnut 

 timber have been rendered worthless except for firewood. Orna- 

 mental chestnuts in parks and on private grounds also have been 

 killed in many sections. The total financial loss from the dis- 

 ease is estimated now at $25,000,000. The spores of the fungus 

 probably enter the bark through small wounds caused by birds, 

 insects, or abrasions. They commence growth in the cambium 



( 



Fig. 73. Diseased Chestnut bark showing pustules and form of discharge 

 of summer spores in damp weather. (Magnified 3 diameters.) 



