498 



Canadian Forcslry Journal, December, 1919 



AN ODD STUDY OF TREE STUMPS 



Grafted Roots Form Underground Pipe Lines to Keep Alive the 



Defoliated Trunk. 



By C. C. Pemberton, Victoria, B.C. 



The overgrowth on stumps of Douglas and 

 Grand Fir is a very noticeable feature in the 

 woods of the vicinity of Victoria, British Col- 

 umbia, and first attracted my attention many 

 years ago. 



Behevmg that foliage was necessary to mam- 

 tam life m a tree and always finding these 

 stumps more or less m the neighborhood of other 

 standing foliage trees of the same species, I 

 concluded that a union of roots between the 

 stumps and tree was the cause. 



When, however, a few years ago, I began 

 to assemble photographic studies of character- 

 istics of our native trees for the Natural History 

 'Society of British Columbia, one of •^he first 

 things I sought to learn through correspondence 

 with authorities on the subject was the ascer- 

 tained, scientific explanation of the matter. 

 Many conjectures and opinions were expressed, 

 but not a single account of actual investigations 

 was given. 



Among foresters, lumbermen, farmers, etc., 

 to whom I first spoke and who had observed 

 these stumps, the prevailing opinion seemed to 

 be that the growth of new wood was caused by 

 reserve material in stump, and the idea of its 

 being due to root-union was doubted. 



Many botanists to whom I wrote and sent 

 photographs, held that the callus formation was 

 due to reserve material in the stump, while 

 others again expressed the opinion that such 

 vigorous growth was impossible without foliage 

 or root connection with a tree possessing foliage. 



A EUROPEAN VIEW. 



The first person from whom I obtained au- 

 thentic information was Professor Somerville, 

 of Cambridge University, to whom Mr. James 

 R. Anderson, of Victoria, hed sent some of the 

 photographs of these stumps. 



In a letter to Mr. Anderson, April 23rd, 1919, 

 he says (referring to these stumps) : 



"This is the condition of things we often 

 find in the larch in Europe, which, of course, 

 is a deciduous tree, as contrasted with the 

 evergreen character of the Douglas fir. So 

 far as I have observed, the larch is the only 

 conifer indigenous to Europe, which fre- 



quently shows this condition of things, and 

 it is usually attributed to the inarching of 

 roots of adjoining trees, the stump of one 

 that has been felled, procuring a good deal 

 of nourishment from the roots of one or 

 more adjoining trees that have been left 

 growing. 



"I do not know that this subject has been 

 exhaustively investigated, but it would be in- 

 teresting to make an examination of a large 

 number of larch trees which have stood well 

 removed from other individuals of the same 

 species and which have been felled some 

 years before. In such cases, one would not 

 expect callusing of the stools for, if the 

 theory is well founded, it is only where other 

 trees of the same species are left to grow in 

 the immediate neighborhood of one or more 

 that has been felled, that one would expect 

 to find this phenomenon. 



"That the roots of trees in a wood grow 

 together to a large extent is an undoubted 

 fact, and the photographs that you have sub- 

 mitted show this very conclusively. Of 

 course, one can have a certain amount of 

 growth taking place in a stem which has 

 been severed from the stump, provided the 

 stem is laid in a cool, moist place, in which 

 event the cambium becomes active in the 

 spring, and ten per cent or more of an an- 

 nual wood-ring can be formed in the en- 

 suing season. Ihave found this notably in 

 the larch, but I doubt not it occurs in other 

 species." 



MR. PEMBERTON's FINDINGS. 



Whilst, as already related, I sought infor- 

 mation through correspondence with author- 

 ities, I also took every opportunity of investi- 

 gating the characteristic of overgrowth of 

 stumps as well as that of the frequency and 

 cause of root-union. 



I examined a multitude of overgrown Doug- 

 las and Grand fir stumps in the vicinity of Vic- 

 toria, not only those in which root systems were 

 already exposed to view, but by uncovering 

 many others with root systems deeply buried 

 in the soil. 



