Standörtliche Variabilität von subalpinen Fichtenwäldern

ISSN:1422-808

Untersuchungen über den Einfluss unterschiedlicher Kleinstandorte und der Pflanztechnik auf Fichtenpflanzungen in subalpinen Lawinenschutzwäldern

ISSN:1422-114

A Topography-Informed Morphology Approach for Automatic Identification of Forest Gaps Critical to the Release of Avalanches

Human assets in Alpine regions are prone to gravitational natural hazards such as rock fall, shallow landslides and avalanches. Forests make up a substantial share in that landscape and can mitigate those hazards. Management of avalanche protection forests must cope with avalanches potentially released in forest gaps, which can damage downslope forests. The Swiss guidelines “Sustainability and success monitoring in protection forests” prescribe forest-gap extents in slope-line direction critical to the release of avalanches in forested areas. This article proposes a topography-informed morphology approach (TIMA) to automate the detection of critical gaps based on a digital terrain model and a canopy height model (CHM) derived from airborne LiDAR-data. TIMA uses complementary information about topography to probe forest gaps computed from the CHM with templates meeting critical-gap extents adjusted to local topography. The method was applied to a test site in Klosters-Serneus (Switzerland). The comparison of a critical-gap map with the results of a field assessment at 19 sample locations resulted in 84% overall accuracy. Moreover, plausibility of gap detection could be improved by including linear features forest roads and torrent channels in TIMA to account for decoupled snow layer resulting from abrupt breaks on the hillslope. If the TIMA concept can be successfully applied to the case of avalanches, this would encourage its use in assessing other gravitational natural hazard processes.ISSN:2072-429

Laubwälder der Bündner Südtäler

ISSN:1422-808

Participatory modelling of upward shifts of altitudinal vegetation belts for assessing site type transformation in Swiss forests due to climate change

Aims Climate change is expected to markedly change site factors, tree species composition and finally ecosystem services provided by forests. Here, we describe the development of a framework for modelling how these changes may transform forest site types. Site types capture information on site conditions like climate, topography and soil, all factors with strong influence on tree species occurrence. Location Switzerland. Methods We elicited expert knowledge and followed a participatory modelling approach for quantifying upward shifts of altitudinal vegetation belts and the changes in the zonal distribution of main tree species, as a basis for assessing transformation pathways of forest site types for three climate projections. Results The model results show marked range shifts of altitudinal vegetation belts. The change in the vegetation belt and a rule base for forest site type transformations allow for assessing the location-specific and long-term transformation pathway from the current to a future forest site type. Conclusions The resulting maps enable forest managers to take climate change into account when selecting tree species. The presented method complements statistical distribution models as it considers more site information, integrates expert knowledge and is based on a forest site type classification which is already widely used by forest practitioners