Characteristics of Throughfall Erosivity in an Abandoned Moso-bamboo Forest

Ji-Won Park1*, Seonghun Jeong1,2

(1Department of Forest Environmental Resources, Gyeongsang National University,

2Institute of Agriculture and Life Science, Gyeongsang National University)

Abstract: Throughfall kinetic energy (TKE) is widely used as an indicator to evaluate rain drop erosion, the initial stage of soil erosion, and varies depending on stand canopy structure. Bamboo spreads rapidly and invades existing forests, inducing changes in stand structure; however, no study on raindrop erosion in bamboo forests has been done. We investigated TKE using splash cups installed inside and outside a study plot (10 m × 10 m) (inside: n = 30, outside: n = 5), and collected its data at the event scale. To determine influential factors of canopy structures, almost all canopy structures such as plant area index (PAI), canopy cover (CC), distance from a bamboo to a splash cup (Dmin), and first branch height (Hl) were measured. Additionally, a Monte Carlo approach was applied to evaluate stand-scale splash cup sampling strategies. During the study period, throughfall (TF) accounted for 76.3% of total rainfall, and a strong correlation between TKE (J m-2) and TF (mm) was observed (R²= 0.98). TKE was 1.8-fold higher than that of free kinetic energy (FKE). Stand-scale unit TKE (13.6 J m-2 mm-1) was within low values reported in previous studies for other coniferous and broadleaved species. Monte Carlo analysis indicated that at least 15 splash cups were required to achieve reliable  stand-scale TKE measurements, with a coefficient of variation below 5-10%. Our findings implied that the moso-bamboo forests rather than other forest types could have resistance against soil erosion.

Keyword: Bamboo, Raindrop erosion, Throughfall, Throughfall kinetic energy

Acknowledgement: This study was carried out with the support of ´R&D Program for Forest Science Technology (Project No. "RS-2025-02213493") provided by Korea Forest Service(Korea Forestry Promotion Institute).