Effects of natural and planting regeneration on soil properties, forest productivity and economic feasibility 20 years after a forest fire in Goseong

The large-scale forest fires in Goseong and Korea's eastern coastal region in 1996 and 2000 caused extensive ecological and socio-economic damage.In response, natural regeneration (NAT) and planting regeneration (PLT) were applied, and permanent plots were established to monitor long-term changes.This study evaluated soil properties, forest productivity, and economic feasibility 20 years after the fire.Soil analyses across three depths (0 -30 cm) showed that NAT maintained higher pH (6.0), organic matter (2.5%), and nitrogen (0.06%), while PLT had greater bulk density (1.4 gcm -3 ), available phosphorus (14.4 mgkg -1 ), and cation exchange capacity (CEC; 14.9 cmol c kg -1 ).Compared with immediate post-fire conditions, soil fertility partially recovered, with increases in pH (+11%), available phosphorus (+188%), and CEC (+44%), but declines in organic matter (-22%) and nitrogen (-42%).Forest structure also differed that NAT supported higher tree density and seven hardwood species, whereas PLT promoted faster growth, larger diameter at breast height (DBH), and greater leaf biomass.Total aboveground biomass did not differ significantly between NAT and PLT (p = 0.565), despite contrasting stand structure and biomass allocation.Economic evaluation over a 50-year rotation revealed a benefit-cost ratio of 1.24 for PLT, which was more than double that of NAT (0.58).These results indicate that planting regeneration enhances tree growth and economic returns, while NAT sustains soil fertility and species diversity.A complementary approach that integrates both methods may therefore guide more effective regeneration strategies and long-term forest management planning after large-scale fires.