THE CANADIAN FIELD-NATURALIST 



VOL. XXXV. 



GARDENVALE, QUE., MAY, 1921 



No. 5 



OVEKGROWTH OF STUMPS OF CONIFERS. 

 By C. C. Pemberton. 



Perhaps the most remarkable feature in 

 connection with the subject of the over- 

 growth of stumps of certain conifers is the 

 fact that many botanists /lave never heard 

 of the existence of this phenomenon. This 

 is all the more remarkable as it is a phase 

 of vegetable life which has been observed 

 in different parts of the world for a long 

 time and various authorities have, from 

 time to time, i)ublished references to it. 



The findings of those who have investi- 

 gated tjiis subject in one country often do 

 not seem to have been known to those in 

 another, later writers being apparently 

 unaware of previous investigations. Evi- 

 dently the references published in the past 

 have attracted little attention and the sub- 

 ject has been speedily forgotten. 



I have found that many plant physiolo- 

 gists, on learning of the phenomenon, in- 

 cline to the idea that the overgrowth is 

 the result of a mysterious power in the 

 reserve material of the stump which en- 

 ables it to eontiiuie indefinitely to form 

 woody matter without aid of foliage or or- 

 gans of assimilation of any kind. They 

 comment on the fact that broadleaf trees, 

 and even larch, can have their felled stems 

 make a limited amount of callous growth 

 in the spring following t^ie felling. Other 

 physiologists from the first /lave deemed 

 the reserve material explanation utterly 

 inadequate and have considered the con- 

 tinuity of vitality, healings and bulky for- 

 mations of cappings of new wood to be 

 possible only by parasitism of some sort 

 with a chlorophyll-pos.sessing host plant. 



Some years ago. when I took up the 

 study and investigation of the character- 

 istics of the native trees in the environ- 

 ment of Victoria, I found it impossible to 

 discover any authoritative writings on the 

 subject of these stumps, but by degrees I 

 learned that the matter had received at- 



tention from several writers. Unfortun- 

 ately the full texts of these publications 

 have never been obtainable here, and I 

 have, therefore, been unable to ascertain to 

 what extent investigations have been car- 

 ried. 



From Mr. A. D. Webster, whom I first 

 met when Jie was Superintendent of Reg- 

 ent "s Park, England, I have learned that 

 the English forester, Grigor, (who died 

 in 1848) had, in his book Arhoricultnre, 

 referred to the power of coniferous trees 

 to eontinue the formation of healings and 

 new wood after the loss of their stems and 

 foliage ; that while this statement had been 

 scoffed at by subseqvient; Frenc^i reviewers 

 of the book, Mr. Webster's father, Mr. 

 John Webster, who had noted the charac- 

 teristic in Larch, Silver Fir, Scotch Fir 

 and Spruce, had b}' production of actual 

 specimens been able to prove that Grigor 

 was correct in his assertions; and that the 

 findings of Mr. John Webster had then 

 been publis^ied in an essay "On the Growth 

 of Roots of Coniferous Trees After being 

 Felled," which appeared in the Transac- 

 iioHs of the Highland Agricultural So- 

 ciety", No. Ill, Fourth Series, 1870-1871. 



In Elwes and Henry, Trees of Great 

 Britain and Ireland (privately printed, 

 MCMIX) vol. IV, p. 726, I find that men- 

 tion is made of these overgrowths as being 

 the result of root graft, and in a foot-note 

 (No. 'i) reference is given to Mathieu, 

 Flore Forestiere, 529 (1897). 



W. Dallimore, in his article "Natural 

 Grafting of Branches and Roots", in Kew 

 Bulletin, Nos. 9 and 10 (1917), p. 305, 

 quotes the German authority, Sorauer, 

 {Handhuch der Pflanzenkrankheiten, Ber- 

 lin, 3rd Ed. 1909, Vol. 1, p. 774). From 

 perusal of a translation of a transcript 

 from Sorauer (kindly obtained for me by 

 Mr. G. B. Sudworth, dendrologist, U. S. 



