Forests and Woodlands

A forest is an area with a high density of trees. There are many definitions of a forest, based on various criteria. These plant communities cover approximately 9.4% of the Earth’s surface (or 30% of total land area) and function as habitats for organisms, hydrologic flow modulators, and soil conserves, constituting one of the most important aspects of the Earth’s biosphere. Historically, “forest” meant an uncultivated area legally set aside for hunting by feudal nobility, and these hunting forests were not necessarily wooded much if at all. However, as hunting forests did often include considerable areas of woodland, the word forest eventually came to mean wooded land more generally. A woodland is ecologically distinct from a forest.Ecologically, a woodland is an area covered in trees, differentiated from a forest. In these terms, a forest has a largely closed canopy – the branches and foliage of trees interlock overhead to provide extensive and nearly continuous shade. A woodland, on the other hand, allows sunlight to penetrate between the trees, limiting shade. Woodlands may support an understory of shrubs and herbaceous plants (often including grasses). Woodlands may form a transition to shrublands under drier conditions. 

Woodland is used in woodland management to mean any smaller area covered in trees, however dense. The term Ancient Woodland is used in nature conservation to refer to any wooded land established for a very long period (equivalent to the term old growth forest).

Woodlot is a closely-related term, which refers to a stand of trees generally used for firewood. While woodlots often technically have closed canopies, they are so small that light penetration from the edge makes them ecologically closer to woodland than forest.

A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to 6 m; some authors set a minimum of 10 cm trunk diameter (30 cm girth). Woody plants that do not meet these definitions by having multiple stems and/or small size, are called shrubs. Compared with most other plants, trees are long-lived, some reaching several thousand years old and growing to up to 115 m (379 ft) high.Trees are an important component of the natural landscape because of their prevention of erosion and the provision of a weather-sheltered ecosystem in and under their foliage. Trees also play an important role in producing oxygen and reducing carbon dioxide in the atmosphere, as well as moderating ground temperatures. They are also elements in landscaping and agriculture, both for their aesthetic appeal and their orchard crops (such as apples). Wood from trees is a building material, as well as a primary energy source in many developing countries. Trees also play a role in many of the world’s mythologies (see trees in mythology). As of 2005, there were approximately 400 billion trees on Earth, about 61 per person.