Tree definitions vary widely with minimum heights, often at maturity,
of 10, 12, 13, 15 or 20 feet or no specific minimum, just "tall." Some
limit trees to seed plants but seedless plants such as tree ferns,
giant horsetails and tree lycopods are usually considered trees. Most
definitions require that the stem be woody, which would probably
exclude banana, but at least one requires that a tree simply be tall.
Some definitions do not even require that a tree's main stem be
self-supporting so woody vines might qualify as trees by some of these
definitions.

http://www.google.com/search?hl=en&l...&q=define:tree
http://dictionary.reference.com/search?q=tree

The term tree can be applied to many bonsai but the definition of
bonsai itself includes a modification of plant size. The definition of
bonsai usually mentions a plant or tree that has been intentionally
miniaturized or dwarfed. The term miniaturized or dwarfed overrides
any height minimum in the definition of tree, as does "dwarf tree."
People may prefer to refer to a young specimen of a tree species as a
tree seedling, sapling or young tree to indicate that it had not yet
met the minimum height for a tree. In some areas, there are pygmy
forests where soils or environmental conditions limit mature tree
height to well below 10 feet. They are still trees but might better be
described as pygmy trees or dwarfed trees.

When used in tree rose, tree geranium, tree lantana, tree coleus, etc.
the meaning of tree is that the plant has a tree shape with a single
main stem and crown of foliage but does not necessarily meet the 10
foot-plus minimum height. Tree roses, tree geraniums, etc. are also
called standards. Woody vines, such as Wisteria spp. and Campsis
radicans, can be trained to have a single, self-supporting stem so
they look like trees but usually don't meet the 10 foot or more
minimum either.

So-called clump birch are sometimes the result of planting three
saplings in the same hole so they may represent multiple trees rather
than multiple trunks.

Welwitschia is often referred to as a tree or dwarf tree, which seems
reasonable.
http://www.google.com/search?hl=en&i...a+tree&spell=1



(Iris Cohen) wrote in message ...
most definitions of trees include some means of
distinguishing them from shrubs, generally height.

The one I am familiar with is that a shrub is a woody plant which is usually
under ten feet tall & has multiple stems. A tree is usually over ten feet tall
& usually has a single stem.
What about dwarf trees which are way under ten feet tall & might have multiple
trunks, like a dwarf birch? I would assume if the standard plant is a tree, the
dwarf form is also called a tree. Tsuga canadensis 'Minuta' is still a tree,
albeit 3" tall.

Iris,
Central NY, Zone 5a, Sunset Zone 40
"If we see light at the end of the tunnel, It's the light of the oncoming
train."
Robert Lowell (1917-1977)