302 A MANUAL OF FORESTRY. 



Fungi prey upon Scotch Pine to a very considerable 

 extent. Pkytophthora omnivora kills very young 

 seedlings. * Young plants and trees up to an age of 

 about 30 years lose their needles after becoming yellow 

 or brown ; the cause of this has not yet been satis- 

 factorily explained, though in many cases a fungus 

 (Hysterium Pinastri) is present, and may occasion the 

 disease, which is termed Schiitte in German. Both 

 Agaricus melleus and Trametes radiciperda do much 

 damage. Peridermium Pini causes cancer by drying 

 up the bark and cambium all round the tree, and kills 

 the part above it ; such trees in England are called 

 "foxy." White-rot is produced by Trametes Pini; 

 red-rot by Potyporus vaporarius and mollis ; a bluish- 

 black rot by Cerastoma piliferum. 



Pruning of green branches cannot be recommended ; 

 dry branches may be removed. Occlusion is slow. 



Thinnings may be commenced between the ages of 

 10 to 20 years, according to circumstances ; they should 

 be light and frequently repeated until middle age. If 

 it is then decided to underplant the Scotch Pine, the 

 thinnings must become heavier; if not, they should 

 continue to be moderate, so as to preserve as complete a 

 cover as practicable. At the same time, trees are 

 constantly dying off from various causes, such as insects 

 and fungi, or they are broken by snow and rime. Such 

 trees must be removed as speedily as possible; hence 

 dry-wood cuttings are more frequent in Scotch Pine 

 woods than in any other. 



