FOREST PROTECTION 89 



As a parasite on conifers, it proves fatal to young and old 

 trees alike. The fine white mycelium between the wood and 

 the bark, the black rhi-zomorphs and the clotted mass of earth 

 and resin adhering to the roots and collar, serve to determine 

 the fungus in the absence of the yellow or honey-coloured 

 caps which appear in late autumn. The strong mycelial 

 strands or rhizomorphs extend under the surface of the 

 ground in search of healthy roots, which they pierce and 

 enter, to the destruction of the plant ; also infection is 

 brought about by spores from the fructifications. 



Prevention : Pull up and burn infected young conifers. 



Pendermmm Pint corticola. On the upper part of the 

 stem or in the crown of the Scots Pine a black resinous 

 patch, or " blister," and in June the orange-yellow sporophores 

 (fructifications), mark the presence of this common fungus. 

 The mycelium lives in the soft bast and in the region of the 

 cambium, which it kills. As the canker on the stem in- 

 creases in size, the passage of the elaborated sap is confined 

 more and more to the healthy side ; the sap-wood, too, 

 may become clogged with turpentine to such a degree that 

 the supply of water from the roots is interfered with, and 

 the portion above the canker dies in consequence. Young 

 trees are quickly killed by it, though often indirectly, for 

 they get suppressed by neighbouring trees. Older stems 

 are able to hold out longer against it. 



Trees affected by the disease should be at once removed. 



Aecidlum elatinum, a canker of the Silver Fir. Swellings 

 with deep cracks or fissures occur on the stems, caused by 

 the mycelium working in the cortex. The "witches '-broom" 

 of the Silver Fir is attributable to this fungus, and branches 

 with these curious growths should be pruned off before the 

 shedding of the spores in June or July. Infested stems are 

 rendered more liable to wind-break, and should be removed 

 in all cuttings as they occur. 



Trametes radiciperdq, is the most destructive root fungus of 

 the Scots Pine, Weymouth Pine, and Spruce. If one tree 

 dies from it, others whose roots are in contact soon follow, 



