Effects of mixture on mineral elements and essential oil composition of Phoebe bournei

To investigate the effects of stand age and organ differences on mineral element allocation, essential oil yield, and major components of Phoebe bournei under mixed planting with Cunninghamia lanceolata, this study selected 5;10;and 15 year old C. lanceolata-P. bournei mixed forests and pure P. bournei forests of the same ages in Jindong Forest Farm, Yongzhou, Hunan Province. The mineral element contents, essential oil yields, and major components in the leaves, branches, stems, and roots of P. bournei were determined. The results showed that mixed planting significantly altered the mineral element contents and allocation patterns among different organs of P. bournei. Meanwhile, mixed planting reduced the essential oil yields of leaves and branches, but increased those of stems and roots, with the highest essential oil yield observed in roots from the 15 year old C. lanceolata-P. bournei mixed forest. Essential oil yield and major components were jointly affected by organ type, stand age, and mixed planting. Among the major components, β-caryophyllene, α-pinene, and calarene showed significant changes. Overall, C. lanceolata-P. bournei mixed planting can markedly affect mineral element uptake and allocation, essential oil yield, and the composition of major components; however, the response patterns varied among organs and stand ages.