Relationships of light environment to stand attributes in a stand of bamboo, Phyllostachys pubescens

We investigated the relationships between the light environment beneath a forest canopy and stand attributes, i.e., culm density and total basal area, in a stand of bamboo, Phyllostachys pubescens. Mazel ex Houz. based on a thinning experiment. A 15 m × 15 m plot was established in the stand and 10 successive thinning regimes were performed, so that thinning ratio by the number of culm for each thinning was approximately 5%. The digital hemispherical photographs were taken before and after each thinning, and the sky factor was computed as a measure of light environment from the photographs. The light environment became brighter and homogeneous as the thinning regimes progressed. The culm density was a good predictor of the light environment, and the relationship between sky factor and culm density could be well expressed by an exponential equation. Because of the larger culm sizes and total leaf area, the change in light environment with thinning was more sensitive in the P. pubescens stand than Phyllostachys bambusoides Sieb. et Zucc. stands examined in previous studies. This suggested that species characteristics should be carefully considered when elaborating culm density control for improving light environment in bamboo stands.