Relationship between above-ground biomass allocation and stand density index in Populus × euramericana stands

摘要

The relationships between above-ground stem, branch, leaf masses and stand density index (SDI) were analysed in Populus × euramericana (Dode) Guinier stands in Jiangsu Province, China. The allometric equations developed in this study accurately estimated masses of above-ground and specific above-ground tree components in stands with different SDIs. The relationship between the mean above-ground mass w and the ratio of stem to the above-ground (w_S/w) was examined. With increasing w, the stem mass ratio w_S/w increased. Mean masses of above-ground and tree components decreased significantly with increasing SDI at age 9 years, indicating the presence of competition-induced limitations to growth. The mean above-ground mass–SDI and mean component mass–SDI were strongly correlated with above-ground mass-SDI and tree component mass–SDI, respectively. An equation describing the relationship between the mean leaf area u and SDI was developed, which fitted well for the u-SDI data. Stem mass increment exponentially increased with increasing leaf area index.