ROOT WEDGING AND ROCK DISINTEGRATION

Plants and their roots are very active in the process of rock disintegration and weathering. We are all familiar with sidewalks that have been lifted and cracked by tree roots. Most of us have seen concrete cracks widened by weed growth. Yet plant roots have been almost completely ignored by geomorphologists in their studies of weathering agents. Common opinion has been limited to the view that plants prevent erosion rather than cause it. The importance of plants in erosion control was given widespread popular recognition early in the nineteenth century after the Alpine torrents were blamed on the removal of vegetation by man. Modern stabilization programs for freeway slopes, sand dunes, and farm topsoil all now rely heavily on various sorts of plant cover. Concern for erosion prevention on unconsolidated surfaces has hindered the full appreciation of plant roots as agents in the disintegration of rock slopes.