Analysis of landslide movement using tree ring-width variation: An example from the Usubetsu-gawa Landslide, Hokkaido, Japan

Abstract

In May 2000, a very substantial landslide occurred in Sapporo. It was later named the Usubetsu-gawa Landslide. A dendrochronological study using the tree ring-width of living trees in this landslide area was used to examine the response of the rings to disturbances owing to previous landslides. The tree ring-width chronologies in the active landslide area were poorly correlated with the average Usubetsu-gawa chronology made using living trees growing outside the landslide area. This was explained as resulting from repeated landslides that altered tree thickening owing to root breakage caused by surface cracking and to canopy gaps produced by fallen or tilted surrounding trees. The variation in the tree ring-width chronologies on various slopes and micro-landforms suggests differences in the movement history within the same landslide area.