Kim Carpenter, age 11, of Campbellsburg, Kentucky, for her question:

Is it true that trees fight pollution?

The plant world thrives on decayed organic material in the soil and converts our waste carbon dioxide into fresh breathable oxygen. This is what nature intended, and these recycling systems worked successfully through the ages. But nowadays, the human population is producing more wastes than nature can handle. And some are pollutants that harm plants as well as animals and people.

It would be nice if the plant world could dispose of all our messy pollutants. We could relax and continue to dump our foul wastes into the streams, the air and the soil. But obviously the trees and other plants cannot cope with the problem. Otherwise our world would not have become polluted. It is true that trees can dispose of some of our wastes, but they cannot continue to do so without a lot of human help.

Trees and other plants can dispose of our kitchen garbage. But this organic waste must be properly processed and mixed with the soil. Many cities have seen the light in this respect. They have started sensible systems to collect kitchen garbage and fallen leaves. Instead of sending this organic material to incinerators to add smokey pollutants to the air, they ship it out to the farms. There it is mixed with the soil, where nature's worms and multitudes of micro organisms are waiting to decompose it. By this modern method, a previous pollutant becomes a valuable fertilizer, eagerly consumed by trees and other plants.

The green world also removes our waste carbon dioxide from the air. But some people think that the leafy trees also can remove all sorts of air pollutants. This is far from true. Some of these noxious gases are deadly dangerous to the plant world. In regions of dense smog pollution, many of the trees wither and die and smaller plants fail to grow.

At present, pollution has the upper hand and nature's recycling systems cannot continue without human help. It is up to us to provide cleaner air and water. Then the trees can survive to dispose of our organic garbage and waste carbon dioxide  just as nature intended. But we cannot depend upon them to dispose of our noxious pollutants as long as we continue to pour them into the air, water and soil.

Fortunately we have started to mend our messy habits before pollution became a hopeless problem. As things improve, let's plant more trees and let's not forget to cherish the ones we have. Our survival depends on the survival of the green plant world. When a tree absorbs waste carbon dioxide, it converts it into a fresh supply of breathable oxygen. And countless green trees are eager to co operate  because this is how they get their basic food.