GIS‐analysis of tree‐line elevation in the Swiss Alps suggests no exposure effect

摘要: . Counter intuition, an analysis of tree-line position across the Swiss Alps based on a geographical information system (GIS) with spatial resolution 100 m (2.5 million points) revealed no difference in climatic altitude slope exposure. Through step wise discrimination procedures our accounts for anthropogenic depression. Any land cover bias affects frequency GIS-points corresponding to forests rather than mean elevation such points, captured by analysis. We explain this phenomenon (1) absence significant drought effects (no disadvantages southwest slopes), (2) fact that tree tops, unlike low stature vegetation, do not profit from greater radiation warming south slopes during growing season but are thermally coupled free air circulation, and (3) preliminary data root zone temperatures season, which differ between north slopes, as long soil is screened closed forest canopy. The overall length snow cover, often seen does seem affect explains natural fragmentation slopes. It patchiness (avalanche tracks, beds etc.) have nourished idea generally lower limit growth lines at northern These results line recently developed theory, suggests elevations humid climates correspond similar isotherms, irrespective latitude thus, length.