THE CONIFERS 175 



4-| feet by A.\ feet, and thinnings should be very lightly con- 

 ducted, because clean timber will never be obtained if the 

 trees are grown in anything approaching an open state. It 

 is mature at from sixty to eighty years of age. The timber 

 is largely imported from the Baltic under the names of 

 'White deal' or 'White fir'. Home-grown timber is usually 

 very full of knots, but this is due to the fact that it has mostly 

 been grown in woods of too open a character. 



Spruce does not usually pay well in Britain when grown 

 on small areas, but large woods of this tree would probably 

 be very profitable. 



Spruce suffers greatly from insect attack and from fungi. 

 The pine weevil and several bark beetles do much damage, 

 and the Spruce gall aphis (Cherw.es abietis) injures young 

 plants. Of fungi, the Honey fungus (Armillarea mellea] 

 and Fomes annosns do much harm, while Pestalozzia Hartigii 

 causes young plants to turn yellow and die. 



The Sitka spruce (Pice a sitchensis). 



A native of America, it was introduced into Great Britain 

 in 1831. It is a very ornamental tree, of rapid growth, but 

 is tender. It is a moderate shade-bearer and can be used for 

 underplanting. The timber is of a better class than that of 

 the Common spruce, and the tree will probably prove to be 

 worth planting on a large scale in place of the latter. It will 

 succeed on all fairly deep soils except dry sandy ones, and 

 it is a useful tree for stiff clays. It can be treated sylvi- 

 culturally like the Common spruce. The needles being very 

 prickly it escapes damage from animals to a great extent. 



Unfortunately, the Honey fungus attacks it very badly and 

 Chermes Cooleyi may appear. 



The Yew (Taxus baccata}. 



A native of Great Britain. This is a common tree in our 

 woods and is widely distributed, but it is in no sense a tree 



