The best way to plant trees.

We at the American Forestry Association propose that the new decade inaugurated this year be called the Decade of the Tree.

During the 1990s major changes are needed in public policy and personal lifestyle to improve the ecological health of the planet. Tree planting is one of the simplest ways to start the decade on the right foot.

Perhaps no other action is more direct: Plant a tree and cool the globe. This call to action by the American Forestry Association offers each of us an opportunity to change the direction of our personal lifestyle.

Planting trees around our own homes is the logical place to start. It's a personal action that boosts our property value and does something for the environment at the same time. In addition to providing benefits ranging from aesthetics to erosion control, trees help reduce the energy needed for heating and cooling-and thus the fossil fuels burned by power plants. One result is the production of less gas.

Here at AFA we take the job of tree planting very seriously. We believe that major changes are needed in the way people think about trees and plant them. The American Forestry Association has drawn up new guidelines for how to plant a tree, and unless you've been reading a lot of research information lately, you will find many surprises-such as don't dig a planting pit and don't add soil amendments to the planting hole.

We'll admit up front that tree planting is a more involved process than we once thought. The new information we've developed requires more than just digging a hole that fits the root ball. It requires more labor, but the result is also very rewarding. We estimate young trees will grow twice as fast when planted correctly and will live at least twice as long as trees improperly set out.

Planting a tree is a positive action that is made even more positive when the species and individual specimen are carefully selected, the tree is strategically located on the lot, and-what concerns us most in this article-the sapling is properly planted.

Studying the health and survival of community trees, plus working with city foresters around the world, has led us to make new recommendations on how to go about planting. The old standards suggested digging a hole six inches wider and deeper than the root ball. Up until a couple of years ago, the experts also suggested that community tree planters mix peat moss and other soil amendments with the soil backfill. None of this is recommended today.

Over the last few years we have been searching for clues to the declining health of community trees, and we are coming to believe that planting methods are a major culprit. Some oldtimers wrinkle their foreheads and look skeptical when the old methods are challenged. They can take you out and show you tree after tree that survived and is doing fine, thank you.

So why do we feel so confident that planting techniques need updating? The main reason is that home construction has changed greatly since the good old days. Bigger earth-moving equipment and less hand labor are used in creating today's housing developments. Because of the heavier construction equipment, the soil in the average yard is less fertile and more compacted.

Digging a hole in dense, compacted soil and filling the hole with peat moss and other soil amendments is like creating a pot for the tree. The roots grow outward in the soil amendments, and the tree does fine until the roots reach the original soil and the outward growth stops. Instead of spreading into the yard, the roots encircle the planting pit. The "pot" soon fills with roots, and the health of the tree declines.

The crown continues to grow, but the roots do not. Once the tree becomes root bound, its ability to maintain itself during a drought or survive a flood is limited-leading to decline that is often terminal,

So what do we propose? Plant so that roots have a chance to grow into the surrounding soil and produce healthy, vigorous branches, foliage, and roots. Instead of a planting hole, what's needed is a large planting area that is wide but not deep, where the soil is loose and suited for root growth. The larger the area, the better. Here is how it is done (see figure 1):

After selecting a suitable location, mark out a planting area that is five times the diameter of the planting ball. Use a rototiller or shovels to loosen and mix the soil in this entire area to a depth of about 12 inches. Organic matter can be added to the loosened soil so long as the new material is used uniformly throughout the area.

In the center of the prepared area, dig a shallow hole to set the tree, root ball and all. The hole should allow the root ball to sit on solid ground rather than loose soil. Once the ball is set in the hole, its upper surface should be level with the existing soil.

After the tree is properly situated, cut and remove the rope or wires holding the burlap in place and securing any part of the tree. Position the tree so that it is perpendicular to the ground, so the main stem will grow straight up.

Backfill around the root area and gently step the soil to prevent major air pockets, but it is a mistake to pack the soil too hard. Water can be used instead of your foot to help the soil settle and prevent overpacking. Rake the soil even over the entire area and lay mulch on the area using two to four inches of bark, wood chips, old sawdust, pine needles, leaf mold, or the like. Some mulches decompose quickly and will have to be replenished once or twice a year. Maintaining the mulch layer carefully will improve tree growth substantially.

Some planting recommendations suggest mounding the soil at the outer edge of the planting ring to form a water-holding berm. The berm will help hold water, but it may also encourage the root growth to remain within the berm, close to the tree. So berms are not recommended here mulch should hold the water adequately.

If needed, support the tree with a flexible stake so that the trunk can sway in the wind. The movement is necessary for building the trunk's strength. Remove the stake and rope after one year since leaving rope around the tree can kill it.

We hope to have spurred your interest in planting-especially in doing it right. Our focus here is planting, but we don't want to leave you without a few words on selecting a suitable planting location, which is the first step in the whole process.

Paramount in this consideration is energy conservation. Research by Dr. Hashem Akbari of the Lawrence Berkeley Building Laboratory in Berkeley, California, shows that energy savings can run as high as 50 percent when vegetation is properly located.

Researchers Gordon Heisler in Pennsylvania and jack Parker in Florida have helped identify specific optimum locations. The basic model calls for shade trees on the south-facing side of a house, with the southeastern and southwestern sides being the most important locations in terms of summer cooling. The detrimental effects of winter winds are addressed by planting evergreens (pine, spruce, fir, or hemlock) on the northeastern section of your lot. (See figure 2.)

Deciduous trees are the best choice for summer shading since the foliage adds cooling benefits during the hot months, while the leaf drop in fall allows the sun to reach the windows of the house and contribute solar heat gain during the winter.

A minimum of three trees are recommended. They should be sited so they can grow vigorously; allow space for both roots and branches to develop. Species selection should be geared toward producing medium to large trees for these strategic spots so that both the roof and the sides of the building receive shade. As the trees mature, the low winter sun will be able to reach the house from underneath the branches. Evergreen windbreaks work best as group plantings containing at least four trees, but the more the better. Spacing between the trees should be six to 10 feet, which gives the trees some room to grow but allows branches to meet and form a windbreak as the trees mature.

As your knowledge of the landscape increases, you will be able to make many other energy-saving plantings around the home. Trees that shade air conditioners are most effective at improving the efficiency of the cooling units. Trees and shrubs can also be located to direct summer breezes through open windows, shade walls, or create air movement where ventilation is needed. Although strategic location is the most important consideration, the impact of the vegetation is also directly related to its overall size and abundance. The effectiveness of the landscaping at moderating the climate will be increased by filling available space with small, medium, and large plants. Each plant has its niche, so it is the job of the landscaper to review site conditions and select plants that fit the local needs.

When it comes to actual selection, don't assume that the cheapest tree is the best tree. It is usually the worst. One planting recommendation that has remained unchanged over the years is that a quality tree is the best investment.

First, you need to decide which species is the right one for your spot. Be sure to get some help here if you don't know. Some trees grow well on wet sites, and others do better on dry sites. Know the conditions and find out what trees 4o best in your area. Matching a tree to a site is a problem that must be addressed locally. To find answers, ask for information at your state forestry office or Cooperative Extension Service, or go to a local arboretum, garden center, or nursery.

Nurseries offer a tremendous range in quality of trees. Not all the trees are good ones. Two things must be considered by the buyer: First, is this the right tree for my site, and second, is it in good condition and ready for transplanting into the cold, cruel world?

Scientists are working with nurserymen to develop genetically superior trees, and with each passing year, better specimens will become available. As a buyer, you need to be assured that the improved genetic line has been passed along to the young plants. Selecting trees by named varieties or cultivated variety will address some of these problems.

To determine the health and condition of a tree, eyeball the trunk, branches, and root ball for signs of damage, and use the guidelines supplied by the American Association of Nurserymen (see below) to determine if the nursery has handled the tree properly. Nursery growers will refer to their management techniques as cultural practices.

Trimming will give the crown a strong structure and raise the branching up the trunk. Pruning the branches on the main stem needs to be done carefully. The branches help the tree put on caliper (diameter) growth, but if they are left on too long, the wound from pruning can cause considerable damage to the tree. Roots require pruning that produces a fibrous and compact system.

By the time a tree leaves the nursery, its shape, size, and direction of growth have been modified by the nursery's cultural practices to help it survive transplanting and remain healthy.

If a tree isn't properly root-pruned, for example, most of the roots needed for survival will be lost during transplanting. The tree may survive, but it will grow slowly and require a great deal of care. There is a long list of things that need to be done by the nursery to prepare a tree for street planting. The buyer can learn a lot about the quality of a tree by asking one question: Is this tree grown to nursery standards? If no one at the nursery knows what you're talking about, the tree may not be a good choice.

The following is what you should look for when buying a tree. These recommendations are an abbreviated review of the standards published by the American Association of Nurserymen (1250 I St., NW, Washington, DC 20005).

The standard measure for balled and-burlapped trees is caliper, or the diameter measured six inches above the ground (for trees larger than one half inch and smaller than four inches in diameter).

A proper relationship of height to caliper assures that the tree's size is in proportion to the strength of its trunk. The average height of a two-inch-caliper tree is 12 to 14 feet, and the maximum height is 16 feet. The tree pictured in the accompanying sketch is drawn to scale and fits the standards. The tree is 1 1/2 inches caliper and about 10 feet tall.

The amount of roots left on the tree is critical to survival. For bare-root trees, a two-inch-caliper tree should have a minimum root spread of 32 inches. If the tree has a root baH, the ball must be of a diameter and depth to encompass enough fibrous roots for full recovery of the plant. The ball diameter for a two-inch tree is 24 inches, and its depth is about 16 inches.

If all these directions are followed nursery standards, careful selection of species, proper location on your lot, and our new planting recommendations-then you'll have a solid chance of nurturing a healthy tree. Of course, you must water it when necessary, stand guard against errant vehicles, and-just to cover an bets-talk to it occasionally. A kind word never hurt anyone. AF