350 



Note IV. Page 128. 



Opinions quite opposite to these are entertained by Dr. Yule, and 

 also by Sang, who is a nurseryman and a planter of some exjKJri* 

 ence ; but they arc not borne out by facts. The author of the Ency- 

 clopedia of Agriculture entirely agrees in the sentiment expressed in 

 the text, regarding the renovation of the tap-roots in trees. 



" The opinion (he observes), that young plants have not the power of 

 renewing their tap-roots, will, we believe, be found inconsistent with 

 fact ; and we may appeal to Sang, and other nurser3rmen, who raise the 

 oak and horsechestnut from the seed. It is customary, when these are 

 sowTi in drills, to cut off their taproots, without removing the plants, at 

 the end of the second year's growth ; and when, at the end of the third 

 and fourth year, they are taken up, they will be found to have acquired 

 other taproots, not indeed so strong as the first would have been, had 

 they remained, but sufficient to establish the fact of the power of re- 

 nctval. We may also refer to the experiments recorded by Forsyth, 

 which at once prove, that trees have the power of renewing their tap- 

 roots, and the great advantages resulting from cutting down trees, after 

 two or three years planting. Forsyth says, ' that he transplanted a bed 

 of oak plants, cutting the taproots near to some of the side-roots, or 

 fibres springing from them. In the second year after, he headed one 

 half of the plants down, and left the other half to nature. In the first 

 season, those headed down made shoots six feet long, and upwards, and 

 completely covered the head of the old stem, leaving only a faint cica- 

 trix, and produced nev) taproots, upwards of two feet and a half long." 

 — Encyclop. of Agricul. Part III. B. II. p. 572. 



The power, which taproots unquestionably possess, of renewal after 

 being cut, is a point of considerable interest to the art under discussion, 

 and it is important that it should be ascertained beyond controversy, 

 that the cutting of them under ground does no material injury to trees ; 

 otherwise it would follow, that all removal is materially injurious. 



Before we quit the subject of taproots, it is worthy of notice, that 

 the ingenious Mr. Knight, to whom phytological science is under so 

 many obligations, has suggested the notion that gravitation is the agent 

 employed by nature, to make the germcns of plants ascend in the air, 

 and their radicles go down into the earth ; and this doctrine he has en- 

 deavoured to estaltlish, on the ground of experiment. See Philosoph. 

 Trans. 180G, pp. 100, 101, et seqq. But it seems much more reasonable 

 to belicvi', that the radicles of trees possess energies quite capable of 



