ilO JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



forester's command, where dealing with large wooded areas, of 

 improving the shape or " form " of the boles. A perfect clear 

 bole, so far as form is concerned, would be of the same diameter 

 just below the crown and immediately over the surface of the 

 ground — that is to say, it would be a cylinder. Although such a 

 bole is very seldom met with, at least when of any considerable 

 length, it is the ideal form that should constantly be kept in view. 

 The more the bole of a tree deviates from the shape of a cylinder 

 — that is to say, the more rapidly it tapers from base to crown — • 

 so much the more wood must be sacrificed as slabs in manu- 

 facturing the timber. Now, a very brief consideration of the 

 laws of growth will show that in the sylvicultiiral treatment of 

 woods the forester has the power of very considerably modifying 

 and improving the form of trees. The material from which 

 wood and other plant-tissues are formed comes down from the 

 crown, and according as this nourishing stream is great or small 

 so will the total amount of wood formed be much or little. If a 

 tree occupies an isolated position, and possesses a large low- 

 reaching crown, it will be able to produce so much formative 

 material that the cambium at the base of the stem will be as 

 well nourished, and be able to form as broad rings, as the 

 cambium situated higher up. This being the case, it is evident 

 that little if any improvement in form can be expected in such a 

 stem. It may increase very rapidly in volume, but it will always 

 retain a form that necessitates much waste when manipulated in 

 the saw-mill. Trees situated in a wood where a proper amount 

 of closeness has been preserved grow somewhat differently from 

 isolated trees. In their case the crown is confined to the upper 

 half or upper third of the stem, and the sun has free access to it 

 only from above, instead of from all sides. The amount of 

 formative material is thus considerably restricted, being sufficient 

 to afford normal nourishment to the cambium near the source 

 of supply — that is to say, near the crown — but being insufiicient 

 to satisfy the wants of the cambium nearer the base of the stem. 

 The result in this case is that the stem increases in thickness at 

 a greater rate immediately beneath the crown than at any point 

 lower down, and so the tendency is constantly in the direction of 

 improvement of form. Suppose the case of a Scotch Pine which 

 at the age of thirty years, has a diameter of 12 inches at the 

 distance of 4 feet above the surface of the ground, and of 3 inches 



