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