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Z dendrogeomorfološko analizo priraščanja ekscentričnih branik smo na območju plazu Urbas, ki se nahaja na Potoški Planini v severozahodnem delu Karavank, rekonstruirali reaktivacije plazenja v zadnjih 138 letih. Raziskava je temeljila na dendrokronološkem vzorčenju navadne smreke (Picea Abies Karst.) na območjih različne intezitete plazenja. Na podlagi nenadne spremembe indeksa ekscentričnosti 82 ukrivljenih dreves smo identificirali 138 rastnih motenj ter datirali 15 reaktivacij plazu v obdobju med leti 1880 in 2017 (1943, 1944, 1956, 1971, 1977, 1988, 1991, 1992, 1994, 1995, 2007, 2008, 2009, 2012, 2016) s povratno dobo plazenja 9,2 leta. Z uporabo podatkov lidarskega snemanja smo spremembe v izoblikovanosti površja digitalnega modela reliefa (DMR) med časovnim obdobjem 2014 in 2017 primerjali s spremembami ekscentričnosti dreves na isti lokaciji. Povezave med vrednostjo ekscentričnosti in spremembe v površju za obdobje med leti 2014 in 2017 nismo zaznali. Na podlagi časovnih sprememb v indeksu ekscentričnosti in prostorske interpolacije smo rekonstruirali aktivnost plazenja za obdobje od leta 1918 do 2017. Ugotovili smo, da se stopnja plazenja povečuje v osrednjem delu plazu. Nenazadnje smo na podlagi ekscentričnosti predlagali razdelitev oblike debel na sedem kategorij glede na njihovo ukrivljenost. With the dendrogeomorphological analysis of the growth of eccentric tree-rings, we reconstructed the reactivation of landsliding in the last 138 years in Urbas landslide, located on the Potoška planina in the northwestern part of the Karavanke Mountains. The research was based on the dendrochronological sampling of the Norway spruce (Picea Abies Karst.) in areas of varying landsliding intensity. On the basis of a sudden change in the eccentricity index of 82 curved trees, we identified 138 growth disturbances and 15 landslide reactivations between 1880 and 2017 (1943, 1944, 1956, 1971, 1977, 1988, 1991, 1992, 1994, 1995, 2007, 2009, 2012, 2016) with a landslide return period of 9,2 years. Using the data of lidar scanning, the changes in the surface of the digital terrain model (DTM) were compared with the changes in the eccentricity of trees at the same location in the period from 2014 and 2017. No links between the eccentricity or surface changes were detected for this period. On the basis of temporal changes in the eccentricity index and by using spatial interpolation, landsliding activity was reconstructed for the period from 1918 to 2017. We found that the intensity of landsliding increases in the central part of the landslide. Lastly, we proposed a categorization of tree trunk shapes into seven categories with respect to their stem curvature on the basis of their eccentricity. |
