306 Studies in Forestry [CHAP. xm. 



partly in the timely pulling or digging up of the sickly plants, and partly 

 in isolation of the infested patch by means of narrow trenches. But the 

 best and most important general measure to be recommended is the 

 immediate removal of all diseased plants from the woods, so as to hinder 

 further infection being spread by their spores. Keeping the woods clean 

 is an essential condition to the maintenance of their health.' 



Even a very superficial study of the character and life-history 

 of the more important fungi causing diseases among our forest 

 trees cannot fail to show the immense importance of the main- 

 tenance of close canopy, so as to hinder a rank growth of 

 shrubs, berries, and weeds on the soil, which may tend to 

 reproduce and spread heteroecious fungi. The necessity for 

 keeping the woods clean and free from suppressed material in 

 a more or less sickly condition will also be evident, as also for 

 cutting out the soft-wooded trees like Aspen and Birch when- 

 ever it may be suspected that Pine or Larch trees in the 

 vicinity are suffering from fungous disease. But even if con- 

 siderations as to fungoid diseases alone are not sufficient to 

 urge that woods should be kept clean and free from sickly 

 growth, it should also be borne in mind how very much 

 greater and more frequently disastrous are the dangers at the 

 same time incurred from noxious insects. 



