Tree Uprooting:  Review of Types and Patterns

of Soil Disturbance

 

Randall J. Schaetzl, Scott F. Burns, Thomas W. Small

and Donald L. Johnson

 

            This paper reviews the processes of tree uprooting, examines the classification of pit and mound microtopography and assesses the effects of tree uprooting on soil mixing and genesis.  The processes by which soil-horizon clasts are mixed as they slump off the root plate, and the ultimate patterns of soil horizonation within mounds, are primary foci of the paper.  Longevity of treethrow mounds can exceed 2000 years, making these landforms more lasting features than is often assumed.  Because of their great longevity, the pits and mounds formed by uprooting have lasting effects on soil morphology.  Soils of these microsites often classify in different soil orders or suborders than do adjacent, less disturbed soils.  The importance of tree uprooting to mass movement processes is examined.  In some areas uprooting may be the primary mass wasting mechanism.  Nonetheless, estimates of the amount of sediment moved and the net distance of transport vary greatly and may in some cases be overestimated.