in the Cultivation of Forest Trees. 459 



two of our most practical men, sometimes write nonsense, and 

 Withers always. In a word, it is this want of indispensable 

 scientific information that has kept arboriculture, in all its 

 branches, down to the low rank of a mechanical art. I should 

 earnestly advise our planters and writers on planting to unite 

 their best efforts in bringing about a new era in this neglected 

 art. They should endeavour, at length, to learn that a tree is 

 not, as many suppose, an inanimate substance, but a living being 

 like themselves ; that in its constituent parts it possesses the 

 same chemical principles as they do, though with different pro- 

 perties and under different laws of organisation. 



Without reviewing the prize essays, it may be stated that 

 both Mr. Grigor's and Mr. Gorrie's are inconsistent in practice, 

 and destructive to the healthy growth of trees. 



The proportions of the stem to the top of the trees are 

 more inconsistent than Pontey's ; his is 50 ft. to 22 ft., theirs is 

 50 ft. to 25 ft., and Gorrie's, 50 ft. to 16 ft. 8 in. the top of the 

 tree. The thinning out of the branches in the top of the tree 

 is injudicious in practice. Such pruning close to the stem, 

 when the diameter is not one inch, carries disease into the 

 pith, and in the course of a few years the trees are decayed in 

 the centre, which may be completely avoided by shortening the 

 branches till the trees are about 18 ft. in height, and, when close 

 pruning takes place, about 15 in. in circumference. The system 

 of said essays puts science at complete defiance. 



The most consistent system, whether it will be found agree- 

 able to science, will be found in accordance with reason, that all 

 trees should have heads conformable to the length of the trunk, 

 and conical longer than spreading heads ; and to show the cor- 

 rectness of my statements, I shall make a few extracts from 

 Professor Lindley's Introduction to Botany, 1839, p. 382. " We 

 see in practice the more plants are exposed to light, when grow- 

 ing naturally, the deeper is their green, the more robust their 

 appearance, and the greater the abundance of their odours or 

 resins ; and we know that all the products to which these ap- 

 pearances are owing are highly carbonised. On the contrary, 

 the less a plant is exposed to the sun's light, the less its lustre, 

 the fainter its smell, and the less its flavour. 



" The fixing of carbon by the action of light contributes in an 

 eminent degree to the quality of timber, a point of no small im- 

 portance to all countries. It is, in a great degree, to the carbon 

 incorporated with the tissue, either in its own proper form, or as 

 resinous or astringent matter, that the different quality in the 

 timber of the same species of tree is principally owing. Isolated oak 

 trees, fully exposed to the influence of light, form a tougher and 

 a more durable timber than the same species growing in dense 



