Seasonal variations and emission fluxes of monoterpene emitted from coniferous trees in East Asia: focused on Pinus rigida and Pinus koraiensis

This study was carried out to understand the characteristic of biogenic volatile organic compounds emitted from coniferous trees. The measured amounts of monoterpenes emitted from Pitch pine (Pinus rigida) and Korean pine (Pinus koraiensis) by season were generally in the order of: spring > summer ≈ fall > winter. The standard emission rate (the monoterpene emission rate at a standard temperature of 30 °C) from the coniferous trees decreased in fall and winter. In particular, the standard emission rates in winter were 1.2–6 times less than those during other seasons. In addition, the standard emission rates of P. koraiensis were significantly lower (3–30 times) than those of other coniferous species. α-Pinene, β-pinene, myrcene, and α-terpinene were the most abundant chemicals generated from P. rigida. However, the contribution of individual compounds to P. koraiensis displayed a different pattern from those from P. rigida and was dominated by α-pinene, d-limonene, and myrcene emissions. The monoterpene emission flux (EF) from P. koraiensis was 3–4 times lower than that from P. rigida.