Trees and shrubs are perennial plants whose stems become woody and last for many years. Trees usually have a single erect stem or trunk which at a certain height branches out to form a crown, whereas shrubs branch from near to, or at, ground level.

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.

In other words, tree with buds arranged in spirals has the leaves also arranged in spirals. Buds are protected against drying out and frost damage by modified leaves known as scales; either by just single scale (willow or plane tree), two scales (alder), or several scales (beech, hornbeam and oak). Distinguishing features of the scales are colour and pubescence. Some trees that bloom in early spring can be identified by the flower buds, which are of different shapes, e.g. willow, elm, poplar and cherry.

Today, metals, ceramics and plastics made by chemical processes have in many instances replaced wood. But wood’s importance and consumption throughout the world is not declining, quite the contrary. Every year the wood from our trees and forests gives us millions of tons of paper.

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.

Broad-leaved trees grown under the same conditions have a short, thick trunk with a broad, low-placed crown. Only certain light-demanding trees such as the pine, larch, birch and aspen, have the lower half of the bole clear of branches and the crown placed high even when grown in the open.