GARDENING : Project Has Shady Intentions

Why would public power companies develop a program to help their customers plant trees in their yards? The reason is simple: Shade trees planted on the south and west sides of a house can make hot summers cooler and cold winters warmer, which helps to conserve energy.

The goal of this ambitious project, called Treepower, is to plant 16 million trees (one for every public power customer in the nation). Co-sponsored by the American Assn. of Nurserymen and the American Public Power Assn., Tree-power also will provide other benefits to the environment, the groups say.

Trees serve as natural air filters, removing dust and carbon dioxide from the air. Root systems of trees can also stem soil erosion caused by wind and rain. This effort is intended to help make up for the great number of trees that are cut down each year; the group says four trees are now lost for each one planted.

As part of energy audits of homes, many public utilities are helping homeowners determine if they need trees.

In California, for example, the Sacramento Municipal Utility District has joined with the Sacramento Tree Foundation as part of its Treepower effort. After customers have an energy audit, they can request trees, which are delivered, planted and cared for by foundation volunteers.