Vegetation damage, post-disaster change degree and driving factors in the cold temperate wind disaster area of Changbai Mountain, China.

Abstract

The typhoon outbreaks of 1986 caused many gaps in the cold temperate coniferous forest and Betula errmanii forest on the western and southern slopes in the Changbai Mountain. In 2017, a research area at the 1600-1800 m altitude in Changbai Mountain was established to explore the damage and changes of forest vegetation disturbed by the typhoon in cold temperate zone and to reveal the regulation of damage on vegetation and post-disaster change as well as the driving factors. The remote sensing data were used to classify research area based on the degree of vegetation damage and post-disaster change. A total of 40 plots were set up for vegetation survey. According to the damage degree of forest structure, three levels of severity of damage to vegetation in the cold temperate zone of Changbai Mountain were classified including gently, moderately, and severely damaged, in which moderately damaged area was largest, followed by gently damaged area and severely damaged area. Tree damage significantly differed among three level areas, with 20%, 50% and 85% reduction of the abundance of dominant trees in gently, moderately and severely damaged areas, respectively. The wind resistance ability of B. errmanii was higher than that of Picea jezoensis. The wind resistance ability of B. errmanii with larger diameter grade was higher than that of those with smaller diameter grade. The severity of damage to vegetation was strongly correlated with slope, with lower severity on the steeper slop area. From 1987 to 2017, the vegetation of wind disaster area significantly changed. The study area could be classified into three levels based on the degree of changing: fast, medium, and slow, with largest area in medium changed, followed by slowly and fast changed. The degree of vegetation changes was strongly correlated with altitude, with slower change at higher altitude area. The recovery rate of trees was slow, with P. jezoensis recovering slightly quicker than B. errmanii. The vegetation change mainly occurred in shrub and herb layers. Shrub layer recovered better than the herb layer in the fast changed area, while herb layer recovered better than the shrub layer in the medium changed area. In the slowly changed area, herb layer was generally low and dense with varying shrub layer.