The photograph above shows the primitive grandeur of undisturbed old-growth forest in the northwest corner of the Mount Rainier National Park. If you were standing in this scene enjoying the panorama, you might think that this massive forest never ends. However, it does indeed end--in natural deserts, valley farmlands, and logged mountainsides--at the park's boundary, just beyond the mountains on the horizon. While gazing at the view, you might also imagine that this forest will endure forever, but that too is an illusion. This forest, and all forests like it, is a finite resource. None of the world's remaining old-growth forests will last even a short time without careful forest management because consumer demand for forest products is enormous and unyielding. For example, the equivalent of all the trees in this picture are cut down within the boundaries of the United States every few months. Photo: Courtesy of Michaela C. Myers.

Although forests can regrow, it takes 20 to 50 years for a regrowing forest to become commercially useful, and it takes 200 years or more for a clear-cut forest to return to an approximation of its original, complex state. However, a regrowing forest cannot even begin to approximate its original state unless a substantial part of the original forest, with all its native plant and animal species, is left standing. Clear-cutting reduces biodiversity by physically removing many species and destroying habitat for many others. Only if enough old-growth forest is left near a clear-cut area it is possible for the original species to return to the regrowing forest. The return of a forest is a slow process.

Clearly, the preservation of forests as a renewable resource for the indefinite future requires proper forest management and accurate information about forest conditions. It is difficult to get sufficient information quickly from our usual vantage point on the ground. Trees and topography block our view. In the photo above, you can see only to the mountains on the horizon just a few miles away. Aerial surveys and photographs provide a better view, and a faster means of gathering information. The best way to quickly see what is really happening to old-growth and regrowing forests is to look at them from space using satellite images. In the following activities, you will learn how to obtain vital information about forests from aerial and satellite images.

[ Viewing Forests from Space ] [ Virtual Ground Truthing ]
[ Forest Management from Space ] [ Forest Fragmentation ]
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