SYLVICULTURAL NOTES ON WILLOW. 271 



occasionally caused by the following species : Idparis 

 dispar, and monacha ; Eriogaster laneslris, Pygcera buce- 

 phala. Rhynchites betulce and its allies cnt and roll up 

 the leaves. The young stems are injured or killed by 

 the larvee of species of Agrilus and Sesia, and by Zeuzera 

 cesculi. The goat-moth, Cossus, lives in older trees, which 

 are also liable in some localities in N. Europe to suffer 

 from the burrows of a bark-beetle, Scolytus Ratzeburgi. 



Birch has no serious enemies amongst fungi. Exo- 

 ascus turgidus produces witch's broom ; Polyporus letu- 

 linus, red-rot ; Polyporus Icevigatus, white-rot. 



Birch is rarely pruned. Thinnings are regulated 

 naturally, as the weaker individuals are speedily sup- 

 pressed by a moderate number of dominant trees per 

 acre. In mixed woods the more valuable species require, 

 during youth, to be protected against the Birch, as the 

 latter generally grows quicker. 



10. WILLOW = Salix (Tournef.). 



Of the numerous species of Willow only the following 

 four need be mentioned here : 



(a.) Common Sallow, or Goat Willow = Salix Caprea, L. 

 (#.) White Willow = Salix alba, L. 

 (c.) Crack Willow, or Withy = Salix fragilis, L. 

 (d.) Osier = Salix viminalis^ L. 



The Willows yield a soft light timber which is little 

 prized, except for some special purpose, as for cricket- 

 bats ; their principal value consists in yielding withes and 

 materials for basket-work, cask-hoops, &c. The wood 

 is not good fuel, but may be converted into charcoal for 



