CONSERVATION issues have grown more complex with changing human activity, but the original question of environmental ideology still resonates: What is the relationship between man and nature? The two men who galvanized the modern conservation movement early in this century were John Muir and Gifford Pinchot. Mr. Muir poetically articulated the concept of preservation; Mr. Pinchot set in motion the machinery of conservation.
Muir urged protection for two reasons: He saw the mountains as sacred temples; and he found nature's right to exist in and of itself. He was ``a harbinger of modern conservation in terms of the rights of nature irrespective of humans,'' says Roderick Nash, author of ``The Rights of Nature.''
Pinchot's concern was to protect resources from wasteful development. ``Conservation means the wise use of the earth and its resources for the lasting good of men,'' he wrote in his autobiography, ``Breaking New Ground.''
Although the two men clashed in one of the fiercest of wilderness battles, both Muir and Pinchot were against destruction of wilderness. ``They were two guys working different constituencies,'' says John Wanamaker, an early president of the Nature Conservancy. ``But they weren't working [at] crosspurposes.''
Rachel Carson and Aldo Leopold put the question of man's relation to nature in scientific terms. Miss Carson in 1962 exposed the dangers of the pesticide DDT in her book ``Silent Spring.'' A decade earlier, Mr. Leopold's posthumously released book ``A Sand County Almanac'' firmly rooted conservation in the science of ecology. These works argued that nature is an interdependent system. Today, on the eve of Earth Day 1990, the struggle between humans and land continues.