SREL Reprint #2189

 

 

 

The relationships between vegetation type and topography in Lassen Volcanic National Park

J. E. Pinder III1, G. C. Kroh2, J. D. White2* & A. M. Basham May2,**
1Savannah River Ecology Laboratory, Drawer E, Aiken, SC 29802, USA
2Department of Biology, Texas Christian University, P.O. Box 32916, Forth Worth, TX 76129, USA
Current address:
*School of Forestry, University of Montana, Missoula, Montana 59812, USA
**Union Pacific Resources, Ft. Worth, TX 76102-6803, USA

Abstract

The relationships between topographic features and the relative abundances of vegetation types were analyzed for the mid-montane conifer forests, the upper montane conifer forests and the alpine areas of Lassen Volcanic National Park in the Cascade Range of northern California using Landsat Thematic Mapper data. Vegetation types were identified from Landsat Thematic Mapper data and included pine, fir, montane chaparral, willow/alder and herbaceous communities. Topographic features including aspect, slope steepness, slope configuration (i.e., convex, straight or concave) and slope position (i.e., ridge top to valley bottom) were computed from USGS Digital Elevation Models. The distribution of montane chaparral was consistent with its dependency on fire with chaparral communities being more abundant on more xeric aspects and on steeper and more xeric slope configurations. Slope position was important in determining the distribution of willow/alder communities which were more abundant in valley bottom locations. Both slope steepness and slope position affected the abundance of herbaceous communities. Herbaceous communities were: (1) more prevalent on steeper slopes due to the distribution of dicotyledonous forb species; and (2) more abundant in valley bottoms due to the distribution of monocotyledonous species in wet meadows. Pines arid firs were separated along a gradient of slope steepness with the firs being more abundant on steep slopes and the pines being more abundant on shallow slopes. In the alpine areas above 2350 m, the abundance of most vegetation types declined with increasinglymesic aspects. This decline may be related to the prolonged persistence of snow in areas of less intense solar radiation.

Key words - Aspect, Chaparral, Conifer, Elevation, Slope, TRMI

 

SREL Reprint #2189

Pinder, J.E., III, G.C. Kroh, J.D. White, and A.M.B. May. 1997. The relationships between vegetation type and topography in Lassen Volcanic National Park. Plant Ecology 131:17-29.

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