{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,31]],"date-time":"2025-10-31T22:06:14Z","timestamp":1761948374746,"version":"build-2065373602"},"reference-count":54,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2018,3,10]],"date-time":"2018-03-10T00:00:00Z","timestamp":1520640000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>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 \u201cSustainability and success monitoring in protection forests\u201d 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.<\/jats:p>","DOI":"10.3390\/rs10030433","type":"journal-article","created":{"date-parts":[[2018,3,12]],"date-time":"2018-03-12T13:13:48Z","timestamp":1520860428000},"page":"433","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["A Topography-Informed Morphology Approach for Automatic Identification of Forest Gaps Critical to the Release of Avalanches"],"prefix":"10.3390","volume":"10","author":[{"given":"Jochen","family":"Breschan","sequence":"first","affiliation":[{"name":"Department of Environmental Systems Science, ETH Zurich, 8092 Zurich, Switzerland"}]},{"given":"Andreas","family":"Gabriel","sequence":"additional","affiliation":[{"name":"Department of Environmental Systems Science, ETH Zurich, 8092 Zurich, Switzerland"}]},{"given":"Monika","family":"Frehner","sequence":"additional","affiliation":[{"name":"Department of Environmental Systems Science, ETH Zurich, 8092 Zurich, Switzerland"}]}],"member":"1968","published-online":{"date-parts":[[2018,3,10]]},"reference":[{"key":"ref_1","first-page":"23","article-title":"Management of protection forests in the European Alps: An overview","volume":"80","author":"Brang","year":"2006","journal-title":"For. Snow Landsc. Res."},{"key":"ref_2","unstructured":"Losey, S., and Wehrli, A. (2013). Schutzwald in Der Schweiz. Vom Projekt SilvaProtect-CH Zum Harmonisierten Schutzwald, Federal Office of the Environment FOEN."},{"key":"ref_3","unstructured":"McClung, D., and Schaerer, P. (1993). The Avalanche Handbook, The Mountaineers."},{"key":"ref_4","unstructured":"Meyer-Grass, M., and Schneebeli, M. (2018, March 04). Die Abh\u00e4ngigkeit der Waldlawinen von Standorts-, Bestandes-und Schneeverh\u00e4ltnissen. In Interpraevent 1992\u2014Conference Proceedings. Available online: http:\/\/www.interpraevent.at\/palm-cms\/upload_files\/Publikationen\/Tagungsbeitraege\/1992_2_443.pdf."},{"key":"ref_5","unstructured":"Frehner, M., Wasser, B., and Schwitter, R. (2007). Sustainability and Success Monitoring in Protection Forests\u2014Appendix 1: Natural Hazards, Federal Office for the Environment FOEN."},{"key":"ref_6","unstructured":"Margreth, S. (2008, January 28\u201329). Die Wirkung des Waldes bei Lawinen. Proceedings of the Forum f\u00fcr Wissen \u201cSchutzwald und Naturgefahren\u201d, Birmensdorf, Switzerland. Available online: https:\/\/www.waldwissen.net\/wald\/schutzfunktion\/schnee\/wsl_wald_lawinen\/wsl_wald_lawinen_originalartikel.pdf."},{"key":"ref_7","unstructured":"Courbaud, B., and Gauquelin, X. (2006). Guide des Sylvicultures de Montagne-Alpes du Nord Fran\u00e7aises, Office National des For\u00eats."},{"key":"ref_8","unstructured":"Margreth, S., Burkard, A., and Burri, H. (2008). Beurteilung der Wirkung von Schutzmassnahmen gegen Naturgefahren als Grundlage f\u00fcr ihre Ber\u00fccksichtigung in der Raumplanung, National Platform for Natural Hazards (PLANAT)."},{"key":"ref_9","unstructured":"Vacik, H., de Jel, S., Ruprecht, H., and Gruber, G. (2010). Waldtypisierung S\u00fcdtirol, Autonome Provinz Bozen-S\u00fcdtirol."},{"key":"ref_10","unstructured":"Hotter, M., Simon, A., and Vacik, H. (2013). Waldtypisierung Tirol."},{"key":"ref_11","unstructured":"Weir, P. (2002). Snow Avalanche Management in Forested Terrain."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"2921","DOI":"10.5194\/nhess-14-2921-2014","article-title":"Quantification of basal friction for technical and silvicultural glide-snow avalanche mitigation measures","volume":"14","author":"Feistl","year":"2014","journal-title":"Nat. Hazards Earth Syst. Sci."},{"key":"ref_13","unstructured":"Margreth, S. (2007). Lawinenverbau im Anbruchgebiet, Federal Office for the Environment."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1002\/hyp.3360050103","article-title":"Digital Terrain Modeling\u2014A Review of Hydrological, Geomorphological, and Biological Applications","volume":"5","author":"Moore","year":"1991","journal-title":"Hydrol. Process."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Maltamo, M., Naesset, E., and Vauhkonen, J. (2014). Forestry Applications of Airborne Laser Scanning: Concepts and Case Studies Preface, Springer.","DOI":"10.1007\/978-94-017-8663-8"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1321","DOI":"10.5194\/nhess-13-1321-2013","article-title":"Automated identification of potential snow avalanche release areas based on digital elevation models","volume":"13","author":"Buhler","year":"2013","journal-title":"Nat. Hazards Earth Syst. Sci."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"305","DOI":"10.1016\/j.geomorph.2004.09.018","article-title":"STARTER: A statistical GIS-based model for the prediction of snow avalanche susceptibility using terrain features\u2014Application to Alta Val Badia, Italian Dolomites","volume":"66","author":"Ghinoi","year":"2005","journal-title":"Geomorphology"},{"key":"ref_18","unstructured":"Maggioni, M. (2005). Avalanche Release Areas and Their Influence on Uncertainty In Avalanche Hazard Mapping. [Ph.D. Thesis, University of Zurich]."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"323","DOI":"10.1016\/S0734-189X(84)80011-0","article-title":"The extraction of drainage networks from digital elevation data","volume":"28","author":"Mark","year":"1984","journal-title":"Comput. Vis. Gr. Image Process."},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Soille, P. (2003). Morphological Image Analysis Principles and Applications, Springer. [2nd ed.].","DOI":"10.1007\/978-3-662-05088-0"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"3049","DOI":"10.1080\/01431160310001657786","article-title":"Quantifying the spatial properties of forest canopy gaps using LiDAR imagery and GIS","volume":"25","author":"Koukoulas","year":"2004","journal-title":"Int. J. Remote Sens."},{"key":"ref_22","unstructured":"Strobl, J., Blaschke, T., and Griesebner, G. (2012). Erkennung von Waldstrukturen aus flugzeuggest\u00fctzten Fernerkundungsdaten\u2014Vergleich von Airborne Laserscanning und digitaler Photogrammetrie. Angewandte Geoinformatik 2012: Beitr\u00e4ge zum 24. AGIT-Symposium Salzburg, Wichmann Verlag."},{"key":"ref_23","first-page":"1209","article-title":"Laser altimetry: From science to commercial lidar mapping","volume":"67","author":"Flood","year":"2001","journal-title":"Photogramm. Eng. Remote Sens."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"863","DOI":"10.14358\/PERS.80.9.863","article-title":"Generating pit-free canopy height models from airborne lidar","volume":"80","author":"Khosravipour","year":"2014","journal-title":"Photogramm. Eng. Remote Sens."},{"key":"ref_25","first-page":"104","article-title":"Generating spike-free digital surface models using lidar raw point clouds: A new approach for forestry applications","volume":"52","author":"Khosravipour","year":"2016","journal-title":"Int. J. Appl. Earth Obs. Geoinf."},{"key":"ref_26","first-page":"45","article-title":"Lidar point cloud based fully automatic 3D single tree modelling in forest and evaluations of the procedure","volume":"37","author":"Wang","year":"2008","journal-title":"Int. Arch. Photogramm. Remote Sens. Spatial Inform. Sci."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1065","DOI":"10.1016\/j.rse.2010.12.011","article-title":"Airborne discrete-return LIDAR data in the estimation of vertical canopy cover, angular canopy closure and leaf area index","volume":"115","author":"Korhonen","year":"2011","journal-title":"Remote Sens. Environ."},{"key":"ref_28","unstructured":"Holmgren, J., Johansson, F., Olofsson, K., Olsson, H., and Glimsk\u00e4r, A. (2008, January 17\u201319). Estimation of crown coverage using airborne laser scanning. Proceedings of the SilviLaser, Edinburgh, UK."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"355","DOI":"10.5589\/m06-030","article-title":"A rigorous assessment of tree height measurements obtained using airborne lidar and conventional field methods","volume":"32","author":"Andersen","year":"2006","journal-title":"Can. J. Remote Sens."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"650","DOI":"10.5589\/m03-023","article-title":"Quantifying canopy height underestimation by laser pulse penetration in small-footprint airborne laser scanning data","volume":"29","author":"Gaveau","year":"2003","journal-title":"Can. J. Remote Sens."},{"key":"ref_31","first-page":"459","article-title":"Integration of tree allometry rules to treetops detection and tree crowns delineation using airborne lidar data","volume":"10","author":"Hlasny","year":"2017","journal-title":"iFor. Biogeosci. For."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"9975","DOI":"10.3390\/rs70809975","article-title":"aTrunk\u2014An ALS-based trunk detection algorithm","volume":"7","author":"Lamprecht","year":"2015","journal-title":"Remote Sens."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"969","DOI":"10.1109\/36.921414","article-title":"A segmentation-based method to retrieve stem volume estimates from 3-D tree height models produced by laser scanners","volume":"39","author":"Hyyppa","year":"2001","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_34","first-page":"925","article-title":"Detecting and measuring individual trees using an airborne laser scanner","volume":"68","author":"Persson","year":"2002","journal-title":"Photogramm. Eng. Remote Sens."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"71","DOI":"10.1016\/S0168-1699(02)00121-7","article-title":"Estimating plot-level tree heights with lidar: Local filtering with a canopy-height based variable window size","volume":"37","author":"Popescu","year":"2002","journal-title":"Comput. Electron. Agric."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"357","DOI":"10.14358\/PERS.72.4.357","article-title":"Detection of individual tree crowns in airborne lidar data","volume":"72","author":"Koch","year":"2006","journal-title":"Photogramm. Eng. Remote Sens."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"950","DOI":"10.3390\/rs4040950","article-title":"An International Comparison of Individual Tree Detection and Extraction Using Airborne Laser Scanning","volume":"4","author":"Kaartinen","year":"2012","journal-title":"Remote Sens."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"27","DOI":"10.1093\/forestry\/cpr051","article-title":"Comparative testing of single-tree detection algorithms under different types of forest","volume":"85","author":"Vauhkonen","year":"2012","journal-title":"Forestry"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"583","DOI":"10.1109\/34.87344","article-title":"Watersheds in Digital Spaces\u2014An Efficient Algorithm Based on Immersion Simulations","volume":"13","author":"Vincent","year":"1991","journal-title":"IEEE Trans. Pattern Anal. Mach. Intell."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"378","DOI":"10.1016\/j.rse.2013.07.044","article-title":"An efficient, multi-layered crown delineation algorithm for mapping individual tree structure across multiple ecosystems","volume":"154","author":"Duncanson","year":"2014","journal-title":"Remote Sens. Environ."},{"key":"ref_41","first-page":"302","article-title":"Assessment of forest parameters by means of laser scanning","volume":"34","author":"Schardt","year":"2002","journal-title":"Int. Arch. Photogramm. Remote Sens. Spatial Inform. Sci."},{"key":"ref_42","doi-asserted-by":"crossref","unstructured":"Dougherty, E.R., and Lotufo, R.A. (2003). Hands-on Morphological Image Processing, SPIE Press.","DOI":"10.1117\/3.501104"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"181","DOI":"10.1006\/jvci.1994.1017","article-title":"An efficient algorithm for drainage network extraction on DEMs","volume":"5","author":"Soille","year":"1994","journal-title":"J. Vis. Commun. Image Represent."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"183","DOI":"10.5194\/isprsarchives-XL-3-183-2014","article-title":"Morphological operation based dense houses extraction from DSM","volume":"40","author":"Li","year":"2014","journal-title":"Int. Arch. Photogramm. Remote Sens. Spatial Inform. Sci."},{"key":"ref_45","unstructured":"Andersen, H.E., Reutebuch, S.E., and Schreuder, G.F. (2001, January 17\u201320). Automated individual tree measurement through morphological analysis of a LIDAR-based canopy surface model. Proceedings of the 1st International Precision Forestry Symposium, Seattle, WA, USA."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"2309","DOI":"10.1016\/j.rse.2007.10.003","article-title":"Identification of gaps in mangrove forests with airborne LIDAR","volume":"112","author":"Zhang","year":"2008","journal-title":"Remote Sens. Environ."},{"key":"ref_47","doi-asserted-by":"crossref","unstructured":"Congalton, R.G., and Green, K. (2009). Assessing the Accuracy of Remotely Sensed Data Principles And Practices, CRC Press. [2nd ed.].","DOI":"10.1201\/9781420055139"},{"key":"ref_48","unstructured":"S\u00e4rndal, C.E., Swensson, B., and Wretman, J. (2003). Model Assisted Survey Sampling, Springer."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"338","DOI":"10.1016\/S0019-9958(65)90241-X","article-title":"Fuzzy Sets","volume":"8","author":"Zadeh","year":"1965","journal-title":"Inform. Control"},{"key":"ref_50","unstructured":"Evans, J.S., Oakleaf, J., Cushman, S., and Theobald, D. (2018, March 04). An ArcGIS Toolbox for Surface Gradient and Geomorphometric Modeling, version 2.0-0; 2014. Available online: http:\/\/evansmurphy.wixsite.com\/evansspatial\/arcgis-gradient-metrics-toolbox."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"159","DOI":"10.2307\/2529310","article-title":"The measurement of observer agreement for categorical data","volume":"33","author":"Landis","year":"1977","journal-title":"Biometrics"},{"key":"ref_52","first-page":"418","article-title":"A universal soil-loss equation to guide conservation farm planning","volume":"1","author":"Wischmeier","year":"1960","journal-title":"Trans. 7th int. Congr. Soil Sci."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"216","DOI":"10.1016\/j.procs.2011.04.023","article-title":"Ridge Detection with the Steepest Ascent Method","volume":"4","author":"Koka","year":"2011","journal-title":"Procedia Comput. Sci."},{"key":"ref_54","doi-asserted-by":"crossref","unstructured":"Riedl, A., Kainz, W., and Elmes, G.A. (2006). Use of Plan Curvature Variations for the Identification of Ridges and Channels on DEM. Progress in Spatial Data Handling: 12th International Symposium on Spatial Data Handling, Springer.","DOI":"10.1007\/3-540-35589-8"}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/10\/3\/433\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T14:56:33Z","timestamp":1760194593000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/10\/3\/433"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2018,3,10]]},"references-count":54,"journal-issue":{"issue":"3","published-online":{"date-parts":[[2018,3]]}},"alternative-id":["rs10030433"],"URL":"https:\/\/doi.org\/10.3390\/rs10030433","relation":{},"ISSN":["2072-4292"],"issn-type":[{"type":"electronic","value":"2072-4292"}],"subject":[],"published":{"date-parts":[[2018,3,10]]}}}