78 The Tree and How it Dies 



soon spreading entirely around the trunk or 

 limb. On smooth, young limbs they form dead, 

 sunken patches of bark, patches thickly covered 

 with orange or reddish-brown spots. This patch 

 or canker grows rapidly, and may girdle the 

 branch completely the first summer. If its limbs 

 are attacked first, the tree may live for some time. 

 But if the canker has formed on the trunk the 

 tree soon dies. 



A very odd kind of fungus is found in some 

 northern forests. Leaves where these fungi have 

 been at work will sometimes swell until they are 

 very large, and look much like a bushy little 

 broom so much so that it is known as the 

 "witch's broom." 



