May, 1921. j 



The Canadian Field-Naturalist. 



87 



sprouts or whether it has the overgrowth 

 tenden'cy. (It would be interesting to 

 learn what the effect of t^iis extensive 

 continuity of root systems had on the 

 stabilizing of the trees in the gale of last 

 winter (Jan. 1921) which did such exten- 

 sive damage uprooting valuable coniferous 

 timber on tlie coasts of British Columbia, 

 Washington and Oregon). At Rouvray, in 

 Fraiyge, while with the Canadian Forestry 

 Corps, I particularly noted that the graft- 

 age of t,he roots of the Pines (Sylvestris, 

 I think), was very noticeable. (Strangely 

 enough, in one case where the bases of the 

 stems of three pines w^ere united and one 

 tree had been felled some time previouslj^ 

 the stump .showed no signs of vitality or 

 overgrowth.) On the other hand I have 

 seen the roots of coniferous trees inter- 

 mingle without apparent graftage ensu- 

 ing, and one often finds the stump of one 

 Douglas Fir tig.htly pressed against the 

 stem of a growing tree -but no sign of vi- 

 tality or overgrowth in the stump. From 

 this I judge that contact and pressure will 

 not always be followed by graftage. The 

 cause of natural graftage of roots was con- 

 sidered by Mr. Dallimore to be mainly 

 pressure, and Prof. Newins assigns the 

 cause to pressure and affinity of species 

 combined with other physical factors. In 

 Elwes and Henry the fact that the bark 

 remains alive to an advanced age is said 

 to account for the vitality and consequent 

 overgi-owth of stumps of Silver Fir. 



The feasibility of utilization of the won- 

 drous creative biological power shown in 

 t^ie continuity of vitality and healing-over 

 of these stumps of coniferous trees does 

 not seem to have ever been contemplated 

 in horticulture or silviculture. 



Living fence posts can be grown, for 

 they do naturally grow, and it should be 

 easy to ensure the graftage of roots art- 

 ificially. Metal or concrete caps fashioned 

 for ornament or use could be placed on 

 the stumps when cut and these would read- 

 ily become enveloped by t^e overgrowth. 

 These posts would last forever. Prof. 

 Xewins menti(ms an instance of an over- 

 growth having 200 rings, and at Stan- 

 ley Park, Vancouver City, close to the 

 "Seven Sisters' there is a capped-over 

 Douglas Fir stump which must be nine or 

 ten feet high. The foster-tree could be re- 

 newed from time to time if it became too 

 bulky. 



It is certain that trees retaining foliage 

 canopy can, by direct root-graft and also 

 apparently by indirect root-graft, trans- 

 mit elaborated sap to remote stumps. The 

 converse might be equally true, and the 

 roots of stumps in moist rich soil might, 

 by root graft, be able to maintain trees in- 

 places of droug^ht and paucity of soil. 



As ordinary grafting is said to be readily 

 a.('('<)m])lished in conifers the retentioTi of 

 vitality by the stumps and roots might be 

 practically turned to account in silvicul- 

 ture and in forestry, and rotation similar 

 to coppice culture attained by grafting 

 sturdy leaders of felled trees on the living 

 stnm])s or roots. This might be especially 

 useful in selecting cuttings in protection 

 forests or parklands. 



I feel convinced that the phenomenon of 

 the root-graft and overgrowth of stumps 

 of conifers is well worthy of greater study 

 and experimental investigation than has. 

 been L'iven to it. 



