wilidlife | trees and woodlands
history
how trees
live and grow
ancient woodland
trees
in Berkshire
how trees live and grow
trees are land plants with woody stems that have the power to grow steadily larger over long spans of years. They are distinguished from shrubs by their distinct main trunks, which develop because of the tallest shoots gains dominance over its competitors, and is therefore called the "leader".
The secret of a trees continued growth lies partly in the winter resting buds at the tips of twigs, which enable the shoots to grow longer each year, and partly in a sheath of tissue called the cambium. The cambium, one cell thick, surrounds every woody stem, and even extends to the underground roots. During the summer, it adds a fresh layer of woody tissue to the stem it surrounds. Thus, each Spring, the cambium adds a narrow light, pale-coloured wood to the outside of the trees woody core. This early springwood, is followed by a darker, denser and stronger zone of summerwood, and the two together form on annual ring. In this way all tree stems get thicker as they grow older, and the base of the tree expands to support the weight of the growing branches and foliage above.
In their natural state trees rarely stand alone. Usually they form plant communities, sometimes of one kind of tree, but often including several kinds, which we call copses, woods or forests, according to their size. Where conditions are right for one tree, other are likely to thrive also. In most natural woodlands, trees of varied sizes and ages, as well as different species, commonly grow together, and compete among themselves for living space.
Natural woodlands have much greater biodiversity than planted forests, where space and tree species are regulated by the forester. Natural woodlands support a large number of plants, insects and animals (flora and fauna). Those of greatest ecological value are specifically designated as Sites of Special Scinetific interest (SSSI) or as National Nature Reserves (NNR's).