l]fi HEART-ROT 



Tho frcqiioncy of heart -rot in plantations which form the 

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

 tions havi' shown tliat lieart-rot is es]ieoially to be appre- 

 hended in eonifei'ons woods when they are planted as the 

 first forest rotation on land wliieli has been previously 

 cultivated. The same applies, though in a lesser degi*ee, to 

 first plantations on commons and heaths. I have personally 

 seen ]ilantations of larch damaged in this way on the Tintern 

 estate, at Terringham Wood near C'inderford, in tlie 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 jilanted as 

 a pioneer rotation, though the second rotation is usually 

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

 for this j)henomenon, I made a special study of a number 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 ]iath 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 ' ])rimary I'ot ' were rotted equally 

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

 the wood had i-eached th(^ pale yellow spongy stage, or had 

 in some cases lu-en destroyed by worms, tlie cavity sur- 

 louiidcd hy the hollow Wark being filled with the worm- 

 easts. Others showed only ' secondary rot ", i. e. they were 

 i-otted only in the centre, like the trunk; the. rot was in 

 an earlier stage, and the rotted wood was surrounded by 

 a layer of gnni. Outside this the young wood and phloem 

 were living and active, it is reasonable to suppose that 

 tlu^ roots which show tiie jn'imary rot are those through 



^ Miitlios (1011) correctly ascrihcd root-rot to the ]uc.scncc of dead 

 roots iuid dead roots to poor mil lit ion imkI soil lUTiUion. 8co also Leslie 

 (19ir.) and I ! iMM-nl i-op (I'.tOS). 



