Characterization of Alpine Treeline Ecotones: an Operational Approach

Publication from Digital

Hill, Granica K., Smith, Schardt M.

Operational Tools in Forestry Using Remote Sensing Techniques, Forestsat 2005, 31st May - 3rd June 2005, Boreas, Sweden, 2006


An ecotone is a zone of vegetation transition between two communities,
 which can result from natural or anthropogenic environmental gradation
 or a positive feedback between vegetation community and environment.
 The transition with altitude from dense subalpine forest to alpine
 meadow or even tundra represents an ecotonal gradient relating to
 increasingly harsh environmental conditions. We demonstrate the use
 of class probability mapping to produce a soft classification of
 an alpine treeline ecotone in Austria using a SPOT 5 HRG image. The
 partitioning of class membership probabilities from a Maximum Likelihood
 algorithm between classes partially reflects the land-cover composition
 of mixed pixels in the ecotone. By identifying thresholds in the
 membership probability scores we map the alpine treeline ecotone
 as a zone of transition. This approach supplies more detailed information
 relating to alpine forests in this treeline ecotone than is displayed
 in a standard hard classification (Core Service Landcover map).

Keywords: soft classification, probability, SPOT, ecotone, alpine treeline