The standard emission rate(ERs) of isoprene was quantitatively measured in situ from Quercus mongolica Fischer that dominates more than about 85% of domestic oak trees. The ERs values in spring and summer were similar to 64.4 and 58.1 (㎍C/gdw/hr), respectively. The ERs in autumn, 7.06(㎍C/gdw/hr), was about 8～9 times lower than those in spring and summer. The coefficient of determination (r2) between ERs and CL․CT ranged from 0.593 to 0.836. The correlation coefficients between the ERs and PAR, the ER and temperature suggested that ERs have strong correlation with PAR(photosynthetically active radiation) and temperature. In addition, the high values of PAR, temperature, and ERs were found in the time zone of 15:00 ～17:00(spring), 15:00 ～ 16:00(summer), and 14:00 ～ 15:00(autumn).

In order to investigate the compositions and the emission rates of monoterpenes emitted from coniferous trees, those from Larix leptoleis (Sieb. et Zucc.) Gordon were measured. In spring and summer, the major monoterpenes were α-terpinene, α-pinene, myrcene; however, α-pinene and α-terpinene were most abundant in fall. The total mean monoterpene emission rates were 0.455 (㎍C/gdw/hr) during the whole period. The higher monoterpene emission rates were found in fall compared to those in spring and summer. In addition, the slopes (β value) between emission rate and temperature were two times lower in fall than those in spring and summer. It was also found that Larix leptoleis (Sieb. et Zucc.) Gordon had lower monoterpene emission rates than P. densiflora and P. rigida.