Seasonal Changes in the Concentrations of Terpenic Compounds Contained in the Leaves of Coniferous Trees

The study compared terpene compounds in five species of coniferous trees and found that Pinus densiflora and Pinus koraiensis did not have high concentrations in their leaves compared to others. However, when volatilized, these species showed high concentrations of terpenes: 8 in Pinus densiflora, 16 in Pinus koraiensis, 10 in Abies holophylla, 1 in Chamaecyparis obtusa, and 2 in Chamaecyparis pisifera. Seasonal analysis revealed that 21 terpene compounds had high concentrations in spring, except for Abies holophylla, which peaked in summer. Overall, terpene concentrations were higher in spring and summer, suggesting these seasons are optimal for extracting essential oils from coniferous trees.