Objective The study aims to explore the effects of different tending methods on understory water-holding capacity of Pinus massoniana plantations in the hilly region of central Hubei Province for providing a theoretical basis to improve the water conservation function of Pinus massoniana plantation forest ecosystem.

Method Based on Pinus massoniana plantations in hilly region of central Hubei Province five different tending methods including control, thinning intensity of 15%, 30%, 45% and structured management were applied. The understory water-holding capacity of understory shrub, herb, litter and different soil layer (0～10、10～20、20～30、30～40、40～60 cm) were evaluated through the indoor soaking method and ring knife method, respectively. And the total understory water-holding capacity was evaluated through the construction of a comprehensive index system (including 3 system layers, 5 standard layers and 28 index layers).

Result Thinning and structured management significantly improved the water-holding capacity of shrub and herb layer. Meanwhile, structured management significantly improved the effective storage capacity (0.61 ± 0.14 t·hm⁻²) and effective retention rate (69.90 ± 32.39%) of shrub, and a thinning intensity of 15% significantly improved the water-holding capacity of herbs. With the increase of thinning intensity, both the maximum water-holding capacity and effective storage capacity of litter layer increased first and then decreased, peaking at 30% thinning intensity. Tending treatments significantly reduced both the natural and field water-holding capacity of soil. Under different tending methods, the total water-holding capacity of understory under thinning intensity 30% (0.546) was the highest, followed by control (0.502), structured management (0.494), thinning intensity of 15% (0.473) > 45% (0.423).

Conclusion A thinning intensity of 30% is recommended for enhancing the understory water conservation function in Pinus massoniana plantations in hilly region of central Hubei Province.