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 ${alpha}-terpinene,;{alpha}-pinene$, myrcene; however, ${alpha}-pinene;and;{alpha}-terpinene$ were most abundant in fall. The total mean monoterpene emission rates were $0.455;({mu}gC/gdw/hr)$ during the whole period. The higher monoterpene emission rates were found in fall compared to those in spring and summer. In addition, the slopes (${eta};value$) 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.) Cordon had lower monoterpene emission rates than P. densiflora and P. rigida.