504 ON USEFUL AND BOOK I. 



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 in- 

 creased by side branches, which retain a large quantity of sap, 

 and by their junction with the stem occasion a contraction and 

 twisted direction of the vessels, which obstructs the progress of 

 the juice. That this is true in fact, is well known to those accus- 

 tomed to make wine from maple or birch trees ; for in this bu- 

 siness it is found that those trees which have fewest side branches 

 bleed more freely than the others, but during a much shorter 

 space. These hints, therefore, afford additional evidence against 

 pruning, and particularly against pruning fir-trees, which, as 

 Mr. Knight justly observes, have larger vessels than most others; 

 and therefore, when in an improved soil and climate, side 

 branches for the purposes above mentioned are essentially neces- 

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



From the foregoing remarks, I think, the following conclu- 

 sions may be drawn respecting the management of trees : 



1. 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. 



