Tree selection an inexact science Sunlight, soil top deciding factors

In fall, our attention naturally is drawn to the thousands of beautiful trees that line the roads and cover the hills of our state. Maine is one of only a handful of states in the United States that is blessed with a cacophony of color in autumn.

A mature, healthy tree can be a thing of beauty. In a season where our attention is focused on these majestic timbers, we might dream of what our yards could look like with the perfect woody plant projecting its beauty around our landscape.

A reader recently wrote, “What do you recommend for shade trees on a city house lot, particularly if one does not want an oak or a maple? Are the new elms practical? How would a sycamore do in Maine?

Consider the following factors when choosing a tree for your site:

. Sunlight and soil: A good, general rule of thumb is this: Think not what tree you’d like in your yard, but what tree would be happy living under the conditions in your yard. This is perhaps the single most important factor in selecting any plant. Don’t try to force a tree whose characteristics you enjoy to live in your yard. You’ll find yourself in an uphill struggle trying to acquiesce the tree or manipulate the environment. A better strategy is to do an inventory on the light, soil, water and air quality and then to select a tree that is tolerant of the site specifications.

. Rate of growth: What role would you like the tree to play in your yard? Do you want to create long-term shade or simply a quick screen from an unpleasant sight? Are you willing to wait years – maybe decades – for the tree to reach its mature height or would you rather have an effect over a shorter span of time? Answer these questions and then research for trees that are a suitable match.

. The level of roadside salt pollution: If winter road crews apply salt to the road you live on, consider carefully where in your yard residual salt might occur. Some trees are more tolerant of salt than others. Deciduous trees such as the Norway maple might be a good selection under heavy salt conditions. Avoid planting evergreens – especially white pines – in areas where there is heavy salting. Remember that evergreens respire and grow – albeit at a very slow rate – even in winter. Salt spray from a passing truck can burn the prickly leaves of the evergreen and cause severe decline or death.

. The effect on your neighbor’s property of planting a tree in your yard: Some city ordinances will do this work for you. Check with your local planning board, town office or city hall for requirements and restrictions that might pertain to tree planting. Some cities detail height restrictions and buffer zones between neighboring lots, in an effort to minimize visual disruption from lot to lot and prevent shade and debris from trees on one lot from affecting the entire neighborhood.

Elms make suitable shade trees in urban settings. The scotch elm, Chinese elm and the Siberian elm are considered fast-growing, very adaptable and easy to transplant.

The sycamore, also known as American planetree, is hardy to Zone 4, reaches 75-100 feet tall and has a fast growth rate. Sycamores are susceptible to anthracnose, a serious disease that spreads rapidly during times of high moisture and affects developing leaves and stems. Disease symptoms known as “witches brooms” often result from this disease. This unsightly illness aside, a sycamore might be a fine choice in a city landscape.

By far the largest group of trees used in an urban setting are members of the linden family. This group of deciduous shade trees has a medium growth rate – they shouldn’t be considered slow growing, but they don’t speedily add height in the way a poplar would, for example.

One linden in particular is spectacular. Know as American basswood, this enormous tree may in fact be too tall for some city house lots, but it’s worth mentioning. At maturity it usually reaches to 60 or 80 feet, although some specimens may stretch to more than 100 feet. This gorgeous specimen has gray bark and a graceful vase-shaped canopy dappled with leaves that are bigger than your hand. Other, shorter lindens, including the littleleaf linden, the Crimean linden and European linden are hardy and durable in an urban landscape.

Diana George Chapin is the NEWS garden columnist. Send horticulture questions to Gardening Questions, RR1, Box 2120, Montville 04941, or e-mail them to dianagc@ctel.net. Selected questions will be answered in future columns. Include name, address and telephone number.