Regional climax forest has a better water conservation function than pine plantation: A comparative study in humid subtropical China

Currently, there is a global trend of rapid expansion of planted forests. However, the effects of plantation forests on hydrological processes, water resource output, and water conservation function (the ability of an ecosystem to intercept, penetrate, and store precipitation in ecosystem) are still unclear. Therefore, we conducted a 4 -year comparative monitoring of hydrological variables (precipitation redistribution, topsoil moisture (0-15 cm), litter moisture, and surface and total runoff) in two distinct forest types in humid subtropical China: a pine plantation (PF) and regional climax monsoon evergreen broad-leaved forest (MEBF). The annual precipitation was comparable in the PF (1841.5 +/- 272.3 mm) and MEBF (2005.4 +/- 268.4 mm). The MEBF had a significantly higher annual stemflow but a slightly lower annual throughfall than the PF. The quantity and proportion of canopy interception loss in the MEBF group were significantly higher than those in the PF group (P < 0.05). Moreover, the MEBF exhibited a greater moisture content in its topsoil and litter than the PF across the yearly, seasonal, and monthly intervals. The annual surface and total runoff were not significantly different between the MEBF and PF during the study period; however, the total runoff in the MEBF during the dry season was approximately 8.4 -fold higher than that in the PF. Overall, the coefficients of variation for the topsoil moisture content, litter moisture content, and total runoff in the MEBF were consistently lower than those in the PF at several temporal scales. The results of this study indicate that the regional climax has a greater capacity for water conservation than the pine plantation, considering the regulation of precipitation redistribution, water storage, and runoff water yield.