66 DISEASES OF DECIDUOUS FOREST TREES. 



With the exception of several months' cut of the hill red oak, the 

 programme was carried out for two years. The numbers at the left 

 of the figure indicate the percentage of timbers upon which masses 

 of wood-destroying fungi were growing and which were obviously de- 

 cayed to a greater or less extent. Tso account could be taken of 

 internal decay, as just referred to, where no sporophores were formed, 

 because it was not possible to cut into the pieces. 



Figure 10 shows one thing very strikingly, namely, the greater per- 

 centage of decay in bottom red oak than in hill red oak. This is espe- 

 cially noticeable for certain months — for instance, August and Sep- 

 tember, 1903, where in the case of the bottom red oak 28 and 42 per 

 cent, respectively, were decayed, while with the hill red oak but 6 

 per cent were decayed. When exposed for but a brief period of time, 

 the difference between the two timbers is not so striking, as is shown 

 by the last months included in figure 10. This is readily explained 

 by the fact that the decay had not advanced far enough for the 

 formation of fruiting bodies of the fungus,, except in those timbers 

 where infection first took place. If the timbers cut in June, July, 

 August, etc., had been left as long as those cut the year before, the 

 difference would probably have been equally as striking as during 

 1903. 



PREVENTIVE METHODS. 



The prevention of decay due to one or the other of the fungi just 

 described may be brought about in one of two ways: First, by placing 

 the wood under such conditions that the wood-destroying fungi can 

 not develop; second, by treating the wood with chemical preserva- 

 tives which act as poisons for the wood-rotting fungi. Both of these 

 methods are successful, and it is usually necessary to employ both 

 in conjunction. 



One of the most important preliminary steps in the handling of 

 timber after it is cut from the log is to dry it out as rapidly as possible. 

 The drying process should aim to remove the water as equably as 

 possible from all parts of the stick, so that excessive checking may 

 not result. Where the drying does not take place uniformly, infec- 

 tion by sap-rotting fungi occurs, as has been most strikingly shown 

 (fig. 11). All wood should be kept from contact with the soil for a 

 certain period after it is cut from the tree, and only after it has been 

 thoroughly dried should it be thus exposed. 



Where wood is to be chemically treated, especially those species 

 which are very susceptible to sap-rotting fungi, like the red oak 

 (Quercus rubra L.), beech (Fagus atropunicea (Marsh.) Sud worth), 

 red gum (Liquidambar styraciflua L.), etc., the greatest care should 

 be used to pile the wood so that no two pieces shall touch more than 

 is absolutely necessary. Timbers should, furthermore, not be piled 



149 



