Abstract: The CO₂ concentration in broad-leaved Korean pine forest of Changbai Mountains was measured continuously with a CO₂ infra-red analyzer in 2003. The results showed that the CO₂ concentration in the forest had striking characteristics of temporal-spatial variations, which were mainly influenced by the physiological processes of plants, soil respiration, and intensity of turbulence exchange. In growing season, the daily maximum and minimum CO₂ concentration appeared mostly on the surface floor at about 5:00 in the early morning and at canopy location at about 15:00 in the afternoon, respectively. There was an obviously process of forest CO₂ emission when the inversion broke at dawn. The average CO₂ concentration in forest was 377 μmol·mol^-1 in 2003, the maximum of monthly average appeared in January as 388 μmol·mol^-1, and the minimum of monthly average appeared in August as 352 μmol·mol^-1. The forest acted as CO₂ source in night time and turned to sink in daytime, during growing season. In non-growing season, the forest acted as CO₂ source in both daytime and night time, but still had a clear evidence of CO₂ assimilation at noon, with canopy location during non-growing season.

Key words: Decapitating, Grazing, Cutting, Artificial grassland, Adaptability