4 THE POLYPORACEAE OF WISCONSIN. 



great size here. The largest tamarack trees were found near Razor- 

 back Lake in a small swamp in the Star Lake Region. Some of these 

 measured thirteen inches in diameter, with an altitude of about seventy 

 feet and an age of one hundred and ten years. 



It is a conspicuous and very important fact that in the region 

 studied, the soundness and healthiness of the trees vary greatly with 

 the locality and with the kind of tree. Certain diseases are, or seem 

 to be, confined to limited localities. One foreman of the Yawkey 

 Lumber Company who has had many years' experience in the woods 

 told me that in the two forties lying between Carr and Horsehead 

 lakes, which are just being cut over, there is a great deal of "ring 

 rot", or "dry rot", while in the cuttings several miles west of these 

 there is very little. A train load of twenty-two cars of logs were 

 counted one day and the proportion of logs showing signs of decay was 

 obtained. In all there were three hundred and one logs of red and 

 white pine of all sizes ranging from seven inches to about thirty inches 

 in diameter. Of these sixty-two showed more or less signs of the ring 

 rot, or twenty and one-half per cent. Six logs had rot produced by Poly- 

 stictus abietinus, or a little less than two per cent. Very little of 

 this rot was found on red pine. The percentage of infected red and 

 white pines in the Star Lake Region is somewhat less. 



A large proportion of the hemlock is infected by Polystictus abie- 

 tiinus, especially near the edges of the forest and in the more exposed 

 parts of it. Fir is comparatively healthy in the Carr Lake region. 

 'There is very little here and it is widely scattered. Firs of more than 

 four or five inches in diameter and sixty or seventy years of age are 

 comparativly rare. In the Star Lake region at least eighty per cent 

 af the fir trees are infected, chiefly with Fomes ungulatus. 



Birch is very much infected with Fomes fomentarius, F. nigricans 

 and Polyporus betulinus, especially in Oneida and Vilas counties. In 

 a small area of about ten acres, out of ninety-seven trees forty-three 

 were infected, or forty-eight and three-tenths per cent. 



The spruce is relatively free from rot. Near McNaughton several 

 larger trees were found infected, one with Trametcs pini and several 

 with Polystictus abietinus. In some swamps a large number of 

 spruces, especially young ones, were infected with a leaf rust which 

 often kills young trees from two to ten years old. The older trees 

 seem to be more or less immune from this disease, or have only the 

 lower branches infected. In one swamp near Star Lake a few witches ' 

 brooms were found on spruce ; the cause of these is as yet uncertain. 



The per cent of tamaracks which are diseased is very variable. In 

 some of the little swamps scarcely a pileus can be found on a tarn- 



