Pamela Nelson, age 14, of Austin, T<ex., for her question:

WHEN WAS CONSERVATION FIRST RECOGNIZED?

Conservation is the wise use of natural resources such as soils, water, plants, animals and minerals. Although the conservation of natural resources has been recognized as desirable by many peoples since ancient times, frequently the basic principles of sound land use have been ignored, with disastrous results.

One of the first steps toward an official conservation policy was the petition to Congress in 1873 by the American Association for the Advancement of Science to halt unwise use of natural resources.

Highlights in conservation history thereafter include the creation of the federal forest reserves (later called the national forests) in 1891, the development of the national park system, starting with Yellowstone National Park in 1872, and the establishment in 1899 of the United States Soil Survey.

The period of drought and soil erosion in the 1930s further stimulated conservation measures. The Soil Conservation Service was established in 1933 to aid in the management of private lands.

With the establishment of the Natural Resources Commission in 1934, a continuing survey of natural resources was begun to recommend plans for their efficient use.

Much significant legislation has been enacted since the 1940s, and in 1970 the Environmental Protection Agency was established.

Conservation of forest trees involves the principles of protecting the tree crop from fires, insects and diseases. Next, the proper harvesting methods    including the replanting of seedlings to replace trees that have been cut    must be used. Finally, complete use of all trees harvested is an important part of the forest trees conservation program.

Conservation of grazing lands and watersheds is also of vital importance.

One of the basic principles of modern wildlife conservation involves the provision of adequate natural food and shelter to maintain the population of each species. The habitat usually determines which wildlife population can exist in a given area.

Among the basic measures for soil conservation currently in use is the zoning of land by capability classes. in this system, the more level and stable soils are designated as suitable for annual crops and other areas are designated for perennials, such as grass and legumes, or for use as grazing or forest lands.

Another conservation method involves the use of soil building plants in crop rotations. Such crops hold and protect the soil during growth and, when plowed under, supply much needed organic matter to the soil.

Special methods for erosion control include contour farming in which cultivation follows the contours of sloping lands and ditches and terraces are constructed to diminish the runoff of water.