In these instances the ground is the principal consideration: but previous to any enquiry into the greater effects of wood, when it is itself an object, an examination of the characteristic differences of trees and shrubs is necessary. I do not mean botanical distinctions; I mean apparent, not essential varieties; and these must be obvious and considerable, to merit regard in the disposition of the objects they distinguish.

Trees and shrubs are of different shapes, greens, and growths.

The varieties in their shapes may be reduced to the following heads.

Some thick with branches and foliage have almost an appearance of solidity, as the beech and the elm, the lilac and seringa. Others thin of boughs and of leaves seem light and airy, as the ash and the arbele, the common arbor vitae and the tamarisk.

There is a mean betwixt the two extremes, very distinguishable from both, as in the bladder-nut, and the ashen-leaved maple.

They may again be divided into those whose branches begin from the ground, and those which shoot up in a stem before their branches begin. Trees which have some, not much clear stem, as several of the firs, belong to the former class; but a very short stem will rank a shrub, such as the althaea, in the latter.

Of those whose branches begin from the ground, some rise in a conical figure, as the larch, the cedar of Lebanon, and the holly; some swell out in the middle of their growth, and diminish at both ends, as the Weymouth pine, the mountain ash, and the lilac; and some are irregular and bushy from the top to the bottom, as the evergreen oak, the Virginian cedar, and Guelder rose.

There is a great difference between one whose base is very large, and another whose base is very small, in proportion to its height: the cedar of Lebanon, and the cypress, are instances of this difference; yet in both the branches begin from the ground.

The heads of those which shoot up into a stem before their branches begin, sometimes are slender cones, as of many firs: sometimes are broad cones, as of the horse-chesnut; sometimes they are round, as of the stone pine, and most sorts of fruit trees; and sometimes irregular, as of the elm.