Impacts of reforestation approaches on runoff control in the hilly red soil region of Southern China

Vegetation structure and soil properties are not only correlated with forest management practices, but also affect soil and water loss significantly. To estimate the long-term influences of regenerating forest cover on soil and water loss from degraded land, the runoff and soil loss in the context of different forest restoration approaches, including a control plot (CL) and plantations of slash pine (Pinus elliottii), Chinese fir (Cunninghamia lanceolata), tea-oil camellia (Camellia oleifera), and natural secondary forest, were monitored in runoff plots over a 4-year period (2000–2003) in a hilly red soil region in Southern China. Relevant ecological factors and management intensity, were also measured. The results indicated that the four forest restoration approaches decreased surface runoff by 63.0–88.1% and soil erosion by 75.5–97.1% compared to the control. Moreover, runoff and soil erosion in tea-camellia plantation (TCP) and natural secondary forest (NSF) plots were significantly lower than with other treatments. Canopy cover, litter fall, plant roots, plant life forms, soil properties, and vegetation structure are important ecological factors that determine the magnitude of soil loss. Vegetation structure and plant life forms are the main factors reducing surface runoff and the movement of sediments. Effective control of soil and water loss in NSF and TCP are closely related to multiply stratified communities and the presence of specific plant life forms (the herbaceous keystone species Dicranopteris linearis), respectively. In addition, the above mentioned factors were sensitive to forest management patterns, including improper mechanical cultivation. Management practices should attempt to minimize disturbances to these factors to control runoff and soil erosion in each forest management unit. In particular, mechanical cultivation should loosen the soil around the base of a tree only, instead of over the entire ground surface, in the early stages of forest restoration.