How does forest structure affect root reinforcement and susceptibility to shallow landslides?

Moos, Christine; Bebi, Peter; Graf, Frank; Mattli, Josias; Rickli, Christian; Schwarz, Massimiliano (2016). How does forest structure affect root reinforcement and susceptibility to shallow landslides? Earth Surface Processes and Landforms, 41(7), pp. 951-960. John Wiley & Sons 10.1002/esp.3887

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Forests can decrease the risk of shallow landslides by mechanically reinforcing the soil and positively influencing its water balance. However, little is known about the effect of different forest structures on slope stability. In the study area in St Antönien, Switzerland, we applied statistical prediction models and a physically‐based model for spatial distribution of root reinforcement in order to quantify the influence of forest structure on slope stability. We designed a generalized linear regression model and a random forest model including variables describing forest structure along with terrain parameters for a set of landslide and control points facing similar slope angle and tree coverage. The root distribution measured at regular distances from seven trees in the same study area was used to calibrate a root distribution model. The root reinforcement was calculated as a function of tree dimension and distance from tree with the root bundle model (RBMw). Based on the modelled values of root reinforcement, we introduced a proxy‐variable for root reinforcement of the nearest tree using a gamma distribution. The results of the statistical analysis show that variables related to forest structure significantly influence landslide susceptibility along with terrain parameters. Significant effects were found for gap length, the distance to the nearest trees and the proxy‐variable for root reinforcement of the nearest tree. Gaps longer than 20 m critically increased the susceptibility to landslides. Root reinforcement decreased with increasing distance from trees and is smaller in landslide plots compared to control plots. Furthermore, the influence of forest structure strongly depends on geomorphological and hydrological conditions. Our results enhance the quantitative knowledge about the influence of forest structure on root reinforcement and landslide susceptibility and support existing management recommendations for protection against gravitational natural hazards.

Item Type:	Journal Article (Original Article)
Division/Institute:	School of Agricultural, Forest and Food Sciences HAFL > Multifunctional Forest Management
Name:	Moos, Christine; Bebi, Peter; Graf, Frank; Mattli, Josias; Rickli, Christian and Schwarz, Massimiliano0000-0003-4652-8102
Subjects:	G Geography. Anthropology. Recreation > GE Environmental Sciences S Agriculture > SD Forestry
ISSN:	01979337
Publisher:	John Wiley & Sons
Language:	English
Submitter:	Simon Lutz
Date Deposited:	17 Dec 2019 11:53
Last Modified:	18 Dec 2020 13:29
Publisher DOI:	10.1002/esp.3887
ARBOR DOI:	10.24451/arbor.8443
URI:	https://arbor.bfh.ch/id/eprint/8443