Example full definition
Here is the full definition of 'tree' from the A-Z of tree terms: A companion to British arboriculture. Terms in bold face have their own entries in the A-Z.
The definition of ‘tree’ is a composite of tree species, tree form and tree size.
Legislation and legal cases addressing the definition have concentrated on tree size. The blue book offers the following: 'A perennial plant with a self-supporting woody main stem, usually developing woody branches at some distance from the ground and growing to a considerable height and size'.
This definition has the three main elements in general form: a woody perennial plant (tree species), ‘having a self-supporting main stem usually developing branches at some distance from the ground’ (tree form), and ‘growing to a considerable height and size’ (tree size).
A plant may satisfy only one or two of the three main elements, in which case it approximates more or less closely to a tree. For example, a stunted clonal jungle of a freely suckering species such as white poplar (Populus alba), say on an exposed coastal site, has tree species but not tree form or tree size; a tall grass such as wild cane (Gynerium sagittatum), which reaches a height of 14m, has tree size but not tree species or tree form; while a piece of broccoli has tree form but not tree species or tree size.
A tall hedge may have tree species and tree size but not tree form; tree seedlings and bonsai have tree species and tree form but not tree size; and numerous kinds of plants such as palms and tree ferns have tree size and tree form but not tree species.
Compare it with the abridged online definition here.