PLANTING. 21 



From these facts we may conclude that soluble substances, chiefly 

 vegetable extract, mucilage and carbon, with water as a vehicle and a 

 component, presented to the roots of plants under circumstances varyino* 

 according- to the chemical constitution, and mechanical texture of soils, 

 adapted to the peculiar habits or natural wants of different species of trees, 

 as the oak for instance, and the larch, constitute the food of trees supplied 

 by the soil to the roots; and that atmospheric air of a certain temperature, 

 and degree of moisture, and with freedom of circulation, constitutes that 

 other essential part of the nourishment of trees, which is taken up by the 

 leaves or green system of the plant. 



Air, like water, requires a certain freedom from stagnation or confinement 

 to render its nourishing and invigorating properties available to the leaves 

 of trees; when comparatively stagnant, its valuable properties become lost 

 to plants. This is indicated by the disappearance of the green colour from 

 the leaves, which soon drop off, and are riot reproduced, but the branches 

 die ; a few remaining alive at the top of the stem, may continue the 

 existence of the tree for a few years, but without adding to its girth or 

 solidity of contents. These are the invariable effects of stagnant air, the 

 most common and indeed the only cause of which in plantations is the. 

 neglect of seasonable thinning of the v trees, and the removal of dead and 

 decaying vegetable matter as it is produced. 



The putrefactive fermentation of spray and brushwood left in close 

 plantations where the circulation of the air is confined, produces fetid 

 gaseous matters, alike hurtful to animal and to vegetable life ; the growth 

 of moss on the bark of trees is promoted by it, and whenever this becomes 

 general in a plantation, the progress of the trees is greatly retarded. 

 We cannot better illustrate the importance of attending to this principle of 

 practice in the planter's art, than by stating an instance kindly com- 

 municated to us by high authority* on the subject: in many places over 

 an extent of upwards of a thousand acres of the plantations at Blair Adam 

 the prunings of spray and brushwood, and the loppings of the trees 

 thinned out, for which there is no sale in this country, had been allowed 

 to accumulate for many years. The injurious effect was so remarkable, 

 that the proprietor determined to have the accumulation removed. This 

 was done at an expense not very considerable. Ever since the accumulation 

 has been prevented by having a squad of women and boys, to clear away 

 and brush after the woodcutters or pruners. The expense of this operation 

 has been overpaid by the increase of growth, and it is evident that it has 

 added greatly to the value and beauty of the woods, as well as to the 

 growth of underwood f. 



To have entered more minutely into the details of the vegetable 

 physiology would have been incompatible with the scope and design of 

 this essay, and to have dwelt less on those principles which bear directly 

 upon every operation of the planter's art, would have rendered the practical 

 details which follow, more obscure and less instructive, 



* The Right Hon. Lord Chief Commissioner Adam. 



t We have had the gratification lately of examining a considerable part of these 

 plantations, and at the same time of witnessing the triumph of art in rearing valuable 

 timber on situations of great elevation, and in many places more or less elevated, \i\ 

 which wet and undrained land presented difficulties to be encountered and overcome, 



