Abstract: This paper deals with the canopy disturbance regimes and gap regeneration in a Korean pine-broadleaved forest in the nature reserve of Jiaohe Forest Farm, northeast China. The results showed that the percentages of expanded and canopy gaps in the forest landscape is 18.09% and 12.51% respectively. The return interval of canopy disturbance is about 700a. The average size of CG is about 69% of EG size. The range of EG size is 17~284m², with an average of 75.49m². The range of CG size is 10~234m², with an average of 51.98m². The average diameter of most gaps are about 20-60% of the average height of canopy trees. Most gaps were formed by one gap maker, and the most important manners of gap formation were breakage at trunk base and uprooting. Major gap makers in the forest were Pinus koraiensis, Abies holopylla, Betula costata and Picea jezoensis. The DBH of most gap makers were 40~80cm, and their heights 25~30m. The distribution pattern of gaps in the forest landscape belongs to the uniform type. The quantitative characteristics of different tree species in gaps and non-gap stands are different. With the alternation of gaps and non-gap stands, the relative dominance of different species changed correspondently. Tree species were classified into three regeneration response types according to the difference of orders of importance values in gaps and in non-gap stands. Diversity characteristics of species were also different in gaps and non-gap stands.

Key words: Canopy disturbance, Gap regeneration, The Korean pine-broadleaved forest