Effects of post-fire vegetation recovery on soil erosion in vulnerable montane regions in a monsoon climate: a decade of monitoring

Abstract

In areas with frequent fires and erosive soils under monsoon climate, we aimed to determine the long-term dynamics of soil loss during vegetation recovery and to examine elapsed time for soil stabilization. Runoff plots were installed in Pinus densiflora forests affected by stand-replacing fires on the East Coast of South Korea, which occurred in spring 2000. Runoff plots measured runoff and sediment yields for 11 years (2003-2013) during which time, vegetation cover of low-, intermediate-, and high-vegetation cover plots increased from 21 to 44%, 49% to 69%, and 87% to 95%, respectively. Vegetation was effective in preventing runoff and sediment yield. Nevertheless, to stabilize to below baseline load, it took 7 years at low and intermediate cover plots and only 3 years at high cover plots. For 7 years, 7.06 (5.2-fold) and 4.29 (3.1-fold) kg m2 of soil were lost at the low and intermediate cover plots, respectively, compared to the high cover plots (1.37 kg m2). Sediment loss fluctuated more than runoff following extreme rainfall events. We suggest that for the slow recovery area (<70% cover), appropriate measures should be introduced to prevent soil erosion immediately after a fire, and logging should be postponed until the soil is stabilized for 3 years even in fast recovery areas (>70% cover).