The twigs of all trees are covered with buds which, especially in the case of broad-leaved trees which are without leaves in winter, are an important means of identification. Buds are actually embryonic shoots, containing immature leaves or flowers protected by scales.
Plants are a necessary condition of civilization, and of all life on Earth. Without plants, which are capable of’ producing organic material from chemical compounds and radiant energy from sunlight, there could be no life, no animals, not even man, for they provide the basic source of food and nourishment.
The trunks of conifers generally extend to the very tip of the slender, conical crown with layers of fairly thin branches usually growing out at right angles. This type of trunk and branching is characteristic of the spruce, fir, Douglas fir and most larches; in the broad-leaved trees it is to be found in the alder and the pyramidal forms of such species as the Lombardy poplar (Populus nigra).
A further good means of identification in some trees are the short, peg-like projections known as spurs (cherry, apple) on which the flower buds are borne. Some trees’ twigs have distinctive large or small leaf scars which remain after the leaves falhe horseshoe-shaped ones of horse chestnut are noteworthy.
The complex of a tree’s branches and twigs is called the crown, and the trunk or bole and crown combined form a characteristic shape or habit which enables the expert to identify them even from a distance. Frequently, however, the light and wind, have a conical trunk with a centre of gravity below the mid-point and a crown that reaches almost to the ground.
Vegetation, and, above all, trees are also important from the aesthetic viewpoint – refreshing both to the eye and spirit. How bleak and depressing a landscape without trees would be; and what a beautifying and softening effect wisely-placed greenery has, as it enhances modern buildings and constructions. That trees and forests are a source of profound aesthetic experience and inspirations is testified to by the works of prominent painters, composers as well as the motifs of popular folk songs. Today all civilized nations are making a concentrated effort to protect and increase greenery in cities and countryside. If we are to do a good job of protecting and propagating trees, however, . we must know more about them, learn their life secrets and their requirements. Equipped with the necessary knowledge about trees and shrubs we will be better able to select species suitable for a given environment, and will be rewarded by their good and healthy growth.