THE ENEMIES OF ENGLISH WOODLANDS 305 



for many years in a slow and indefinite manner, and without 

 affecting the functions of the sap-wood of the trunk, or killing 

 the side roots outright. In its earliest stage, heart-rot may 

 be detected, when a tree is cut, by the dull foxy-brown or 

 liver-coloured patches of wood which are irregularly dis- 

 tributed amongst the lighter-coloured heart-wood, and these 

 patches often extend irregularly into the sap-wood. The term 

 " pumped " is often applied to trees which are found to be 

 hollow when cut, but we believe that typical pumping is the 

 direct result of fungoid attack, while heart-rot may arise in the 

 deterioration of the tree itself. The former disease may be 

 found in trees of considerable age, and which are otherwise 

 healthy and vigorous, and the pumping often follows the hne 

 of the annual rings more or less definitely ; whereas heart-rot 

 seems to be a slow but irregular change and deterioration in the 

 tissues of the wood, much as if the natural sap were extracted 

 from the heart- wood to supply a deficiency in the sap-wood, 

 and may be found at the age of ten years and upwards. In 

 fact, the particularly early age at which it appears is its 

 worst feature, for it often renders entire plantations perfectly 

 worthless for any useful purpose before their twentieth year, 

 whereas merely blistered trees are often as sound and durable 

 as any. 



As already said, no definite conclusions appear to have 

 been arrived at as to the cause of this disease, beyond the 

 fact that it is due to soil. Had it been caused by a specific 

 parasite, no doubt its life-history would have been worked 

 out by half a dozen investigators, and we should have had 

 scientific controversies over it in abundance. But forestry 

 scientists rarely help us much in cases of this kind, and when 

 mere everyday influences are at work we have to fall back 

 on practical experience. 



Our ovra belief is that heart-rot is due to defects in the 

 chemical and physical properties of the soil, and that the 

 disease is merely the first stage of that premature decay 

 which results from imperfect nutrition, and, later on, fungoid 

 infection takes place and accelerates the process, probably 

 Polypori of various kinds being the common source of infection. 

 Of the two, it is much more common on dry soils than wet, 

 unless the former are subjected to a wet climate ; and it is a 

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