Landslide-induced changes of vessel shape in Betula pendula roth. :a preliminary study

Abstract

Investigation of relationship between vessel structures and exogenous geomorphic processes like landslides, rockfalls, debris flows as well as snow avalanches are common in present dendrogeomorphology. However, very little is known yet about change of the shape characteristics of vessels of Betula pendula as a result of different mass movements. Analysis of vessel lumen length (LL) and width (LW) change on 49 microsections prepared from 15 landslide-disturbed-birches was the goal of this study. A relationship between LW and LL was reported for the year before (2010) and after (2011) landslide separately using equation of linear regression. To evaluate inter-annual variability of changes in shape parameters of tracheas, the proportions of LW and LL in year 2009 was also described for 8 disturbed trees. Slope of the regression line very well characterizes the relationship between LW and LL and evaluation of inter-annual change between LW and LL was carried out based on annual change index (ACI). ACI was defined as a value of percentage change in the slope of the regression lines before and after the landslide disturbance. There is statistically significant change in vessel shape parameters between the years 2010 and 2011. Overall, the highest values of ACI were calculated in microsections sampled in the direction of slope distribution - side of reaction wood production, where ACI2010/11 average value was higher than 43% which is twice more than values from other samples. Increasing of isodiametricity is also typical, while it was found at 65% of analysed disturbed samples.