Visualization of past forest conditions from historical aerial photography

T. M. Williams 1, B. Song 1 and D. J. Lipscomb 2

Baruch Institute of Coastal Ecology and Forest Science, Clemson University (1)
Department of Forestry and Natural Resources, Clemson University (2)

Most trees have life spans that are many times that of human beings. For many species, a middle aged stand will not change appreciably during a human lifetime. To be successful forest education must first counter the emotional predisposition to view forests as eternal. Forestry professionals are trained to visualize forests from tables of data on tree species, size, and density. This ability allows professionals to understand forest conditions occurring long before their birth and predict consequences of their actions that will occur long after they have died. Recent advances in computer gaming allow near photographic quality reproduction of three-dimensional objects. Past or future forests can now be rendered as three-dimensional views on a computer screen. Data contained in forest histories or in growth models can be used to create scientifically valid representations of forest conditions. A professional forester now has a tool to communicate century long visions of the forest to the general public. Historical aerial photographs are views of the entire forest and accurately represent the size and distribution of trees at a point in time. We now have remote sensing and GIS techniques to remove distortion of historical aerial photographs as well as semi - automated methods to identify tree crowns. Aerial photography can provide tree position and relative tree size. Stand records can then be used to correlate relative tree size to actual tree sizes and develop a realistic map. With such a map, we can produce a visualization of the forest with realistic trees with the same species, size, and position as the actual forest at the time of the photograph. We will demonstrate these techniques on Hobcaw Forest , Georgetown County, SC. The impacts of Hurricane Hugo will be represented by visualizations in 1975 and 1991.

Keywords: Silviculture, Extension, three-dimensional views

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