Pruning Trees. 555 



overturned, on the same principle as any weight or force acts on 

 a lever. When wind is of such force as to be equal to a pressure 

 of from 12 lb. to 17 lb. on the square foot, the pine and fir tribe 

 are often so injured that they show symptoms of decay and die. 

 Larch, of all trees, is most susceptible of injury from high winds 

 and the neglect of thinning. Spring should be well advanced, 

 and the trees breaking out into leaf, before the thinning of 

 neglected plantations commences ; being pardy exposed by the 

 thinning, the action of light and air contributes, in an eminent 

 degree, to the strength and quality of the timber. It is said that 

 isolated oaks, fully exposed to the influence of light, form a more 

 durable timber than the same species which have grown in dense 

 forests : so with other species. 



Different opinions undoubtedly prevail regarding the sub- 

 ject of distances in planting, some preferring one distance and 

 some another; the same with respect to the time and modes of 

 thinning: but, being convinced by experience of the utility of my 

 method, I should like to have the reasons of opposition from 

 those who disagree with me. 



Biggar, Sept, 1841. 



Art. V. On Pruning Trees. By Peter Mackenzie. 



We are informed by old writers that the ancients held the 

 pruning of trees to be of so much benefit that they had a god- 

 dess who presided over the operation. Her Ladyship would 

 probably be installed into that office by old Sylvanus, the re- 

 puted deity of the woods and forests ; and in their deep recesses 

 they could say — 



" Lucis habitamus opacis." 



[We dwell in shady groves.] 



Whether her local habitation was in the Lucus Petelinus, or 

 in the groves of Pontus, or in merry Sherwood, or in the Sylva 

 Caledonia, I am not informed; but one thing is certain, if ever 

 there were such persons, real or imaginary, they have long since 

 forsaken this part of the world, and gone I know not whither, 

 perhaps to the celestial empire, and left us under the influence 

 of Discordia. It is not to be wondered at that our arboriculturists 

 should differ so much both in opinion and practice regarding the 

 cutting of a branch, when they divide and continue to diverge so 

 far concerning the junction of a leaf. 



Mr. Cree tells us of the large healthy leaves produced by 

 his system of pruning, and shows us, upon physiological prin- 

 ciples, that by means of them a large increase of wood is pro- 



