PREVENTIVE AND COMBATIVE MEASURES. 73 



on a roadside as in some countries, is an object of such value 

 that, if need be, costly methods can be employed on its behalf. 

 Its branches must be kept free of all intruders like the 

 mistletoe, witches' brooms, mosses and lichens, and above all, 

 from the sporophores which indicate the presence of a wood- 

 destroying fungus. This is all the more easy because the trees 

 are frequently closely examined for pruning, for crop, or for 

 insect attacks. The sporophores of fungi on stems and branches 

 should, as already indicated, be early and carefully cut out, the 

 wound scraped and tarred over.^ In this way the fungus will 

 be deprived of its sporophores and the safety of other trees 

 ensured, although it must be remembered that the mycelium 

 still continues to destroy the wood and probably to produce 

 new sporophores. If the sporophores appear on weak branches, 

 these would best be completely cut ofi' and the cut end tarred 

 over. Trees although diseased and requiring annually to have 

 sporophores cut out should still be spared, as they often continue 

 to live and yield heavily for years. Amongst the sporophores 

 which appear frequently on fruit-trees are those of Polypoms 

 igniarius, P. fvlvus, P. hispidus, P. sulphureus, P. sqioamosus, 

 P. spumeits, Hydnum Schiedermayri, and others to be more closely 

 considered in the special part of this work. 



Particular attention of this kind is of course more difficult 

 for the park-gardener, because his trees are higher and stand 

 closer together. The trees are, however, of less value individually 

 than fruit-trees. It is advisable, as far as possible, to keep the 

 trees clean, to tar all wounds and to remove poorly developed 

 branches and stems. 



To the forester in high forest all this is, however, a matter 

 of difficulty. The trees are high, the forest large, and the 

 individual trees of a value which does not allow of costly 

 labour being expended on them. Yet there is one forest 

 operation in which a plantation may at small cost be easily 

 cleared of diseased stems. This is the repeated process of 

 thinning, during which all diseased and backward trees should 

 be felled. In forests of high value with high-priced timber 

 and near towns or centres of industry, this cleaning out is, of 

 course, easy, but in remote forests with a small working staff, 



1 The sporophores cannot be removed too young ; the wounds produced should 

 • loe treated with tar ; see Section m., p. 77. 



