Trees symbolize stability.  Grandparents tell their grandchildren how they, too, played beneath that tree.  People feel at home when their trees bloom.  Analyzing why you want a tree before you buy one may lead to your selection becoming a "family tree."

What do you want from a tree?  Shade is probably your first request.  But also consider your overall landscape design, soil type, and climate.

Often, homeowners not only want shade, they want it fast.  Fast-growing trees, however, have some drawbacks.  The silver maple grows quickly, and its leaves have an attractive, silvery-gray underside.  But the silver maple also is called the soft maple.  Like many shade trees that grow rapidly, its large limbs can be broken easily by strong winds and ice storms.  Because such trees grow quickly, they need a lot of water, sometimes plugging sewer lines as the roots reach out to any available source of moisture.  Their large roots can also lift sidewalks if the trees are planted too close to them.

An alternative to trees that grow quickly are those maturing at a more moderate rate.  For example, the green ash is a vigorous tree while young, eventually slowing growth to develop a broad crown.

If you want shade in a short time, extra care can help any tree.  Fill around the roots with good soil at planting, keep it watered, and guard against pests.  With this care, even a slow-growing tree can produce shade faster than you might expect.

Trees can also enhance your landscape design.  Be sure you know the height of your choice when it's full-grown.  Those small evergreen trees, often sold as shrubs, can grow to be giants if they aren't suited to heavy pruning.  Lofty trees often blend with older homes on large lots, but low, ranch-style homes mix well with the horizontal branching of smaller trees.

Small shade trees, such as corkscrew willow (Salix matsudana 'tortuosa' ), Russian olive, or amur maple, work well on today's pocket-size properties.  They protect the house from the elements and cut down the summer temperature indoors.  A Japanese maple, for example, can fit into a nine square foot area without impeding traffic--and it doesn't require constant pruning to keep it in bounds.  Dogwood, redbud, and crab apple are also suitable.

Though not a conspicuous part of your design, the soil around your home helps to determine what will grow and what won't.  Marshall's seedless ash (a green ash variety) and the Japanese pagoda tree flourish in dry soils that are hard to keep watered--those with slopes or open southern exposures, for example.  Weeping willow, larch, holly, red maple, or sweet gum can thrive in low, wet ground.  Sandy soils often demand trees with deep roots, such as quaking aspens (Populus tremuloides), pignut hickory (Carya glabra), or scarlet oak.

Temperatures limit your selections, too.  Wind and cold are a ferocious duo, but some trees--such as white ash, white oak, Scotch pine, and Siberian elm--are hardy enough to survive both.

A special hardiness is required for trees in urban areas.  The ginkgo has been around for thousands of years but has been able to survive in modern air pollution.  Other smog-resistant trees include ash, cedar, and cypress.

Frequently, however, city trees need to be not only tough, but small enough to be planted near overhead power lines.  Hawthorns and crab apples fill these needs.