200 TREE WOUNDS AND DISEASES 



the main anchor roots. Rarely is the dense 

 timber attacked by decay when seasoned ; and 

 a peculiarity of the walnut is that, though the 

 trunk may become hollow, the top is quite 

 green. Apt to get uprooted. 



Willows of various species, but particularly 

 the most valuable, in a commercial sense at 

 least the white or Huntingdon (Salix alba) 

 fall a prey, when at all diseased, to fungus 

 and insect attacks. Hollow stem, too, is 

 frequent in old age, and even in young 

 specimens when unsuitably placed ; but the 

 tree is wonderfully recuperative, and frequently 

 sends out roots from far up the main stem. 

 Pollard willows often form roots at the crown 

 and send them down to the soil through their 

 own hollow stems, and the same has been 

 noticed in the yew, elm, white bean tree, and 

 mountain ash. No great expense should be 

 gone to in the case of the willow, though 

 -bracing branches that are likely to fall away 

 and so mar the appearance of the tree is to be 

 recommended. 



In and around London many willows have 

 during the past ten years been attacked by 



