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1 prefer deducing from llic facts already stated this proposition : that 

 whatever tends to increase the wood in a greater degree than what is 

 natural to the species, when in its natural state, must injure the quality 

 of the timber. Pjuning tends to increase this in a considerable degree ; 

 and, therefore, it must be a pernicious practice, in as far as it is used in 

 these cases. — In this Section, I have not considered pruning in regard 

 to eradicating diseases, preventing injuries, or increasing the natural 

 character and tendency of trees. For those purposes it is of great ad- 

 vantage. 



" Mr. Knight has shown in a very striking manner, that timber is pro- 

 duced, or rather, that the alburnum or sapwood is rendered ligneous, by 

 the motion of the tree, during the descent of the true (or proper) sap. 

 It is also sufficiently known to all, who have attended to the physiology 

 of vegetables, and is greatly confirmed by some experiments recently 

 laid before the Royal Society (Philosop. Trans. 1803-1804), that the 

 solid texture of the wood greatly depends upon the quantity of sap 

 which must necessarily descend, and also on the slowness of its descent. 

 Now, both these requisites are materially increased by side-branches, 

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

 occasion a contraction, and tvdsted direction of the vessels, which ob- 

 structs the progress of the (proper) juice. That this is true in fact, is 

 well known to those, accustomed to make wine from maple or birch- 

 trees: for in this business it is found, that those trees, which have 

 fewest side-branches, bleed more freely than the others, but during a 

 much shorter space of time. These hints, therefore, afford additional 

 evidence against pruning, and particularly against pruning fir-trees; 

 which, as Mr. Knight justly observes, have larger vessels than the 

 others; and therefore, when in an improved soil and climate, side- 

 branches for the purposes above mentioned are essentially necessary to 

 them, if solid, resinous, and durable timber be the object in view. 



" From the foregoing remarks, I think the following conclusions may 

 be drawn, respecting the management of trees. 



" First ; That trees should be planted as much as possible in soils, 

 situations, and climates, analogous to those of their natural state ; and 

 that it is chiefly in this state, or where there are some defects relative 

 to it, that pruning and culture can be exercised with advantage. 



" Secondly ; That in proportion to the superiority of the soil, &c. 

 in which trees are placed, over the natural soil of those trees ; in the 

 same proportion pruning ought to be avoided, and thinning encouraged. 



" Thirdly ; That particular regard should be had to the soil and situa- 

 tion, where either larches, or any other of the pine tribe are planted, to 



