CHAP. I. AS COMPONENT PARTS OF GENERAL SCENERY. 195 
may be produced, by the receding or advancing of the terminations of the 
branches ; by the forms of these terminations ; by the manner in which they are 
clustered together ; and by their being open or compact, regular or irregular, 
densely clothed with foliage, or only loosely covered. 
Light and shade. The torm of a tree or shrub is generally indicated by its 
outline against the sky; but that outline does not convey such a correct idea 
of the form as where the space enclosed by it exhibits both light and shade, 
which alone can give it the appearance of substance. 
The capacities of different trees for receiving light vary according to the 
density of the masses of foliage. A compact round-headed tree, like the Sér- 
bus A’ria, will receive and reflect the light in one large mass ; a tree or shrub, 
the general form of which is composed of numerous smaller masses, more or 
less separated from each other, will reflect the light in smaller masses ; and a 
thin tree, which, in many parts, may be seen through, will not reflect the light 
from any part in a conspicuous manner.. In proportion as the light is reflected 
from one side of a tree, the other side will appear dark ; and a tree or shrub 
thinly clothed with foliage will appear to be equally in light and shade throughout. 
Most light and graceful trees are of this description; but the want of the beauty 
produced by light and shade is compensated by the wavy direction of the stem, 
which gives the idea of gentle motion, and by the variety and intricacy of the 
tuftings, outline, and disposition of the smaller branches, spray, and leaves. 
The colours of trees and shrubs vary not only according to the kinds, but ac- 
cording to the season of the year, the climate, soil, situation, age, and other 
circumstances. In general, the colours of spring, when the tree is leafing, are 
more fixed and determinate than those of autumn, when it is losing its leaves ; 
because, in the former case, it depends chiefly on the nature of the tree, while 
in the latter it is materially affected by the weather, and also by the soil. The 
birch, the leaves of which, in most soils, in a wet autumn, will die off of a yel- 
low colour, in a dry autumn will assume a deep red; and, on a peat bog, birch 
leaves generally die off of a pale yellow, while on a granitic soil they generally 
assume a bright red or purple. On the side of the tree next the sun, the leaves 
of all trees are of a brighter colour than on the shady side. Those trees and 
shrubs which vary least in colour, whether in summer or autumn, are the ever- 
greens; and those which vary most are the oaks, the acers, and the thorns. 
The trunks of trees vary as much as their heads ; not only naturally, according 
to the kind of tree, but accidentally, according to the circumstances in which 
it has been placed by nature, or by the hand of man. In general, a detached 
tree exhibits a trunk clothed with branches from the ground upwards; but 
trees grown in masses generally exhibit naked trunks to a considerable height. 
In some species, as in the pine and fir tribe, the length of naked trunk is 
great, in proportion to the size of the head; in others, as in the oak and 
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