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because from their situation they acquire roots, branches, and 

 stems suited to them ; but trees in narrow belts, from being 

 in a thicket while young, acquire great length of stem, but 

 roots and tops proportionally small, so that when thinned out, | 

 from the narrowness of the belt, they become exposed nearly 

 as much as in the single row, and therefore become sickly, 

 from a delicacy of constitution unsuited to this exposure, and 

 from a deficiency of roots to draw moisture commensurate to 

 the increased evaporation. ^i 



The extension of the root is inversely as the induration ; 

 rapid while it remains herbaceous, but slow as it is converted 

 into wood : hence moisture and shade are the circumstances 

 of all others the most favourable to elongation, because they 

 prevent induration, or retard it. Mr. Knight shows that 

 timber is produced, or rather the sap-wood is rendered lig- 

 neous, by the motion of the tree during the descent of the 

 sap. It is also shown that the solid texture of the wood 

 greatly depends on the quantity of sap, which must necessarily ■ 

 descend, and also on the slowness of the descent. Both these 

 requisites are materially increased by side branches, which 

 retain a large quantity of sap by their junction with the stem, 

 and occasion a contraction or twisted direction of the vessels 

 which obstructs the progress of the sap ; the maple and birch 

 which have fewest side branches, bleed more freely than any 

 other. These hints afford additional evidence against pruning ; 

 any deformed branch may be taken off without dressing up 

 trees like broomsticks. 



The forest pruners may stick to their axes and saws and 

 pruning hooks, spite of nature, reason and argument : I will 

 on the present occasion, in obedience to nature and reason^ 

 try to prove by argument, both theoretical and practical, the 

 truth of the maxim, " Prune not at all, if you can help it." 

 The subject only requires a little observation, conducted with 

 common sense. The most inveterate of weeds may be killed 



