Abstract: This paper analyzed the manners of gap formation and the characteristics of gaps in the south subtropical evergreen broadleaved forest in Heishiding Reserve of Guangdong Province. The results showed that the most popular manner of gap formation in the forest was stem breakage (51.86% of the total), and the second, uprooting(39.98%). Most gaps were formed by two trees, averaging 2.63 trees per gap. The size of most expanded gaps was in the range of 100～300m², the gaps of 200～300m² occupied the biggest percentage in area, and those of 100～200m² occupied the biggest percentage in number. The size of most canopy gaps was under 100m², the gaps of 50～100m² had the biggest percentage in area, and those of <50m² had the biggest percentage in number. Most of the gaps were formed 40 years ago, and less than10 years were the most. The diameter at breast height of most gap makers was 20～30cm,and their height were 20～30m. The average area of expanded gap and canopy gap formed by one gap maker was 72.94m² and 25.06m², respectively.

Key words: Gaps, Canopy disturbance, South subtropical evergreen broadleaved forest, rectangular flush, maximum chlorophyll fluorescence under illumination, photosynthetic parameters, multiphase flush