Nature's dust mops

Without trees our earth would be bald. The landscape would appear as though a blight had swept over it. Most song birds would disappear, and planet earth would heat up to an unbearable temperature. The atmosphere would be a constant haze of dust and pollutants.

Nature's dust mops - some over 200 feet tall - would be gone from the scene. Human life would probably be nonexistent.

Without trees, noise would have few barriers, and stress on the ear would triple. Air would be dry, and daily changes from hot during the day to drastically cold at night would be the norm. Damage because of lack of trees as wind barriers is almost beyond comprehension.

One of the questions we ask children when we do Earth Care Workshops with them is: ``Why does temperature on the moon change from more than 200 degrees Fahrenheit during the day to minus 240 degrees Fahrenheit at night?''

Sometimes we take them to a blacktopped parking lot on a hot summer day and have them take the temperature. Afterward, we gather beneath the outstretched arms of a friendly tree and ask them to note the difference. The children's comments and their awakened enthusiasm are amazing.

Though trees do all this good for humanity, historically we haven't paid much attention to them. This is due partly to the quick urbanization of our society as it changed from an agrarian base to an industrial one.

Trees and grass were replaced with ugly factories and tenements. Children of industrial workers grew up without trees. Well-kept grounds were thought to be frills for the rich. As country schools were overtaken and centralized into town and city schools, subjects other than those relating to plants were considered more important.

Now, however, attention to trees and their value is on the upswing. People are demanding more trees along highways and in shopping plazas. They are asking builders to leave existing trees and are seeking the expertise of landscapers. The landscape industry is one of the fastest growing businesses in America, yet job opportunities are begging for qualified personnel.

The United States has some of the best nursery professionals in the world. Most can tell you that a well-placed shade tree in good health can add up to $2,000 or more to the value of your home. A tree that costs $50 today can be worth $400 or more in additional value for your property five years hence.

A properly located shade tree has immense practical value as well. It can reduce summer room temperature by as much as 20 degrees F. Trees not only eliminate ``attic furnace'' in summer, but can cut fuel bills by as much as 30 percent in winter, as they act as windbreaks.

In summer a large tree can have the cooling effect of 10 room-size air conditioners running 20 hours a day, and it takes not one kilowatt to run it!

Unfortunately, trees in the US are dying at the rate of one million a year. Man-made causes are mostly responsible. De-icing salt runoff, lowering of the water table, careless builders, acid rain, and other air pollution are some of the causes. We need at least three trees for each person on earth just to fight air pollution alone.

Motor vehicles greatly contribute to air pollutants. Trees help purify the air by taking out carbon dioxide and giving off oxygen. We should plant 10 trees for every 100 cars and 100 trees for every truck. It takes 100,000 trees to offset the pollution given off by one jet on a round trip from New York to Los Angeles and back. Most US cities are in dire need of more trees. New York City, for example, has only one-quarter a tree per person.

Since noise is also a form of pollution, it is good to know that trees can cut noise by 75 percent. Each 100-feet width of trees absorbs six to eight decibles. Some states wisely mandate extensive plantings of trees along heavy traffic highways.

Some property owners who have trees already on their land may feel that hiring a tree specialist to trim or feed a specimen is money wasted. But if neglected, an injured limb can decay and drop, leaving a stub or hole in the trunk, endangering the whole tree, and making it necessary to eventually remove it. If an arborist is called in promptly, a tree can often be saved, allowing it to serve its purpose for years to come.

Plan before you plant. Once grown to mature height, a tree will probably be there for a lifetime. Take time to select the right kind of tree, and plant it in the right location. They can be planted almost any time of year since most are containerized or root-ball wrapped.

The mature size of the tree should always be taken into account. Large species of shade trees should be placed well away from the house to avoid later maintenance problems. Strong-wooded trees, such as oaks, should be planted no closer than 25 feet from a building; soft-wooded trees even farther. Large shade trees should be planted about 50 feet from each other; medium-size trees, about 35 feet apart. Small trees, such as dogwood, redbud, and hawthorn, may be planted 15 to 20 feet apart, and no closer than eight feet from the house. Avoid weak-wooded types with brittle branches that break easily in storms.

The way you plant a tree today may affect its life 20 years from now. If the tree is containerized, remove the container even if it's papier-m^ach'e (pressed paper). If shrubs are balled and burlapped, be sure to cut the twine and slash the mesh wrapping. Most wrapping is made of nylon, which does not disintegrate. Many trees are girdled because nylon twine is left around the trunk.

Make sure the hole is large enough so roots can be spread out. If roots are tangled and intercrossed at planting time, they will girdle themselves and strangle the tree.

Trees with trunks three inches or more in diameter should be supported by stakes or iron piping. Small trees moved with a ball of earth normally need no stakes. Be sure to water trees thoroughly when planting. Repeat weekly, if rainfall is inadequate, until tree is established.