Acidic cove forest on a mountain creek

Figure 8. Lush forest grows where mountain creeks deposit eroded sediment. (Photograph by Dirk Frankenberg. More about the photograph)

The water that runs off the high slopes and off the Highlands Plateau is quickly organized into creeks and begins its descent towards the sea. The upper reaches of these creeks are too small to have great erosive power, but they can still carry sediments downstream and deposit them in places where the current slows.

Rocky ridges are the speed bumps of mountain creeks. When a creek reaches an erosion-resistant ridge, it either slows to form a pool or curves sharply around it. In either case, the flow slows and suspended sediment settles to the bottom. Changes in water level or the creek channel leave these sediment accumulations available for forest development.

Some of the most diverse, lush, and beautiful forests of the gorges occur along these creeks. One of these is shown in Figure 8. This is an example of an acidic cove forest which is characterized by a lower diversity of mesophytic trees (those that live in the middle range of soil moisture) than rich cove forests, and a shrub layer that often forms a thicket as shown here.

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