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that, even with trees of a youtliful age, the roots and bi anclie:^ 

 are coextensive with each other ; or rather, that superior 

 extent is generally found on the side of the roots. 



In the more confined parts of the forest, the reverse of tliis 

 usually takes place, from the warmth generated by shelter, 

 and the injurious effects of evaporation being obviated. Here 

 roots, and especially fibres are of far less extent and strength, 

 and also fewer in number, than in open positions; and 

 hence the risk, arising from thickets or close plantations be- 

 ing too suddenly laid open, as above mentioned. The want 

 of a stronger system of root in such cases, is sufficiently ac- 

 counted for by the reasonings already given, and by a 

 deficient supply of the descending sap. 



In order to enable trees to withstand the wind, there is no- 

 thing more important than the taproot, or root that has its 

 determination directly downwards. Roots and branches, as 

 has been already observed, are relative and correlative ; and 

 I am inchned to think, that a striking resemblance of cha- 

 racter exists between the leading shoots and the taproots, 

 insomuch that they will be found not only analogous to, but 

 also coexistent with each other. While the tree continues 

 in full vigom", and has not as yet attained its ultimate height 

 or size, it has a leading shoot or shoots at top ; and at that 

 period we find, that there are, in like manner, underground, 

 a leading taproot of corresponding vigour. When the 

 leading shoots of the stem begin to lose their preeminence, 

 and gradually disappear among the other branches, the top 

 of the tree assumes a rounded form, and becomes what is 

 called clump-headed. At this period also the taproot, in 

 the same way, loses its preeminence, and begins to disappear 

 among the other roots : it loses likewise its power of going 

 downwards, and is no longer distinguished among the latter. 

 Thus we may perceive, how remarkable a resemblance the 

 roots and branches of trees bear to each other, not only in 

 respect to form, but also in respect to the period of their 



