Abstract: Based on the investigation at 54 different size gaps of Quercus liaotungensis forest in Ziwuling Mountain, the regeneration niches of different tree species in the forest were analyzed. The results showed that with the variation of gap size, the dominance of the tree species in Q. liaotungensis forest had greater difference. According to their niche breadth in the gaps, the main tree species were classified into 4 types, i.e., wide, medium, comparatively narrow, and narrow, and most of them belonged to the type of narrow niche breadth. The main tree species in the gaps had a smaller niche overlap, with the smallest one in 100-200 m² gaps. The importance value and niche breadth of Q.liaotungensis were higher in 100-200 m² gaps than in 0-100 and 200-300m² gaps, indicating that 100-200 m² gaps were the good habitats for the natural regeneration of Q. liaotungensis.

Key words: Hopea hainanensis, Dipterocarpaceae, Arbuscular mycorrhizal fungi, Frequency, Spore density, Relative abundance