116 HEART-ROT 



The frequency of heart-rot in plantations which form the 

 first rotation on cultivated soil. A large number of observa- 

 tions haye shown that heart -rot is especially to be appre- 

 hended in coniferous woods when they are planted as the 

 first forest rotation on land which has been previously 

 cultivated. The same applies, though in a lesser degree, to 

 first plantations on commons and heaths. I have personally 

 seen plantations of larch damaged in this way on the Tintern 

 estate, at Terringham Wood near Cinderford, in the Forest 

 of Dean, on two separate plantations on the Duke of Bed- 

 ford's estate at Endsleigh, near Tavistock, and two or three 

 more near Brentor in Devon, where in every case the larch 

 was a first forest crop. Other instances have been reported 

 in Britain, and Sir William Schlich tells me that in Germany 

 heart-rot commonly affects the spruce, which is planted as 

 a pioneer rotation, though the second rotation is usually 

 free from it. As no adequate explanation has been advanced 1 

 for this phenomenon, I made a special study of a mimber of 

 trees at Terringham Wood. Thirteen trees were uprooted 

 with the object of finding out through what part of the root 

 system the fungus entered. It was found possible to locate 

 the path of infection, for, although all the roots of diseased 

 trees were rotted to a certain extent, the rotted roots could 

 be divided into two markedly distinct classes. Those which 

 had what I shall term ' primary rot ' were rotted equally 

 from the centre to the cambium ; the bark was dead and 

 the wood had reached the pale yellow spongy stage, or had 

 in some cases been destroyed by worms, the cavity sur- 

 rounded by the hollow bark being filled with the worm- 

 casts. Others showed only * secondary rot ', i. e. they were 

 rotted only in the centre, like the trunk ; the rot was in 

 an earlier stage, and the rotted wood was surrounded by 

 a layer of gum.' Outside this the young wood and phloem 

 were living and active. It is reasonable to suppose that 

 the roots which show the primary rot are those through 



1 Mathes (1911) correctly ascribed root-rot to the presence of dead 

 roots and dead roots to poor nutrition and soil aeration. See also Leslie 

 (191f>) and Rihtontrop (1008). 



