A modified pipe model improved the accuracy of crown biomass estimation in a larch (Larix olgensis) plantation forest in northeast China

Pipe model theory has the potential to be widely applied in the estimation of tree allometry parameters, although it remains uncertain whether it can provide accurate estimation of the crown biomass of plantation forest. In this study, an improved pipe model was used for the first time to estimate the crown biomass of Larix olgensis plantations in northeast China. The results of linear regression analysis showed that crown biomass could be accurately estimated from the stem area at the crown base, which could be calculated using the tree height, crown base height, and stem area at breast height. Furthermore, covariance analysis was applied to analyze the differences in site-related factors that affect crown biomass. There was no significant difference between sites in the crown biomass of L. olgensis plantations in the research area, while the effect of tree age on crown biomass estimation should be considered. Our study showed that a modified pipe model could accurately estimate the crown biomass of larch plantations in northeast China, which has great significance for the determination of crown biomass in Chinese plantations using pipe model theory.