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Directional Positive Feedback and Pattern at an Alpine Tree Line
Kathryn J. Alftine and George P. Malanson
Journal of Vegetation Science
Vol. 15, No. 1 (Feb., 2004), pp. 3-12
Published by: Wiley
Stable URL: http://www.jstor.org/stable/3236489
Page Count: 10
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The spatial pattern at alpine tree line may be part of a feedback process in which wind plays a central role. The basic aspects of such a feedback were embedded in a cellular automaton. Spatial metrics of the patterns generated by this simulation and those of observed patterns at a windy tree line site were ordinated using Principal Component Analysis. Only the simulations that included a directionally weighted feedback fell close to the observed sites in ordination space. MANOVA indicated that the directionally weighted feedback is most important in structuring the tree line pattern, but that random hotspots for establishment and the overall steepness of the environmental gradient from forest to tundra in space also have an effect. The importance of wind in determining feedback with the spatial pattern of a canopy indicates that nonlinear reactions to climatic change are likely.
Journal of Vegetation Science © 2004 Wiley