816 A MANUAL OF FORESTRY. 



rous bark-beetles live in the Larch in common with 

 other conifers. 



Fungi. Phytophthora omnwora kills the young 

 seedlings. Peziza Willkommii eats away the bark and 

 cambium, causing cancer ; this disease has now become 

 so prevalent in many parts of Britain that the further 

 production of the tree has become altogether problematic. 

 Agaricus melleus kills the roots ; Trametes Pini destroys 

 the wood, leaving white spots; Polyporus sulplmrem 

 produces red-rot. 



Pruning. The Larch stands pruning well, but the 

 operation affords an entrance for fungi, especially Peziza 

 Willkommii; hence it should be done very sparingly. 

 It is much better to grow the Larch so that the lower 

 branches die off and fall naturally. 



Thinnings must begin early. They should be light until 

 the time has come for underplanting, when they must 

 be heavy, leaving only healthy, vigorous, well-formed 

 trees as the overwood which are to develop into large 

 timber trees. 



20. DOUGLAS FIR = Pseudotsuga Douglasii (Carr). 

 (The Eed Fir of North America). 



The Douglas Fir is a native of the western part of 

 North America, where it is found between latitudes 

 31 and 55 and longitudes 104 and 130.* It is considered 

 the most valuable forest tree of North America, owing to 

 its rapid growth, great dimensions and the excellence of 

 its timber. The latter is said to be equal to that of 



According to Professor C. S. Sargent. 



