Abstract: The niche characteristics and dynamics of Pinus koraiensis population were calculated and analyzed by methods of Levin’s niche breadth, Hurlbert niche breadth, and Pianka niche overlap in different forest types on Changbai Mountain. The results showed that P. koraiensis population was dominant in original broadleaved and Korean pine forests and the order of niche breadth in the three forest types was: primary forest (OP) > birch forest (BF) > broad leaved and larch mixed forest (MF). Compared with other populations, shadetolerant trees had a higher niche breadth than intolerant trees in OP and it was contrary in the two secondary forests. Additionally, P. koraiensis partially overlapped with other populations in all forest types, and it had an obvious trend of resource sharing with other species in OP and BF. P. koraiensis had the same or similar demands for resource with Acer mono, Tilia amurensis, Acer tegmentosum, Betula platyphylla in OP, Acer mono, B. platyphylla in BF, and Tilia amurensis, Quercus mongolica, Larix olgensis in MF, and would compete with one another under resource shortage.

Key words: sowing date, indica- rice, air temperature, solar radiation, spikelet differentiation and degeneration.