Abstract
China has long been the world's largest producer of pine resin. Pinus massoniana Lamb. It is a significant afforestation and timber species in southern China, accounting for more than half of the forest stock in southern China， It proliferates, with high resin yield, making it an essential component of forestry operations south of mountainous areas and a pillar industry in forestry. However, studies on the impact of resin tapping on biomass allocation and height-diameter allometric growth dynamics of Pinus massoniana are unclear. This study focused on Pinus massoniana plantations in the South Subtropical Region of Guangxi to explore the effects of resin tapping on biomass allocation patterns and allometric growth relationships. Whole-tree harvesting was used to collect samples, with diameter at breast height, tree height, and ground diameter as essential variables to construct allometric biomass models suitable for Pinus massoniana forests under resin tapping disturbance. We constructed allometric growth models for aboveground and belowground parts and between organs to reveal the best biomass models and predictive variables. The results showed that resin tapping disturbance significantly reduced the biomass of various organs in Pinus massoniana, with reductions in stem, bark, root, aboveground, and total biomass statistically significant (P<0.05). However, the changes in leaf and branch biomass were insignificant (P>0.05), indicating that the impact of resin tapping is selective among different organs. The goodness-of-fit of allometric growth models showed that models for resin-tapped Pinus massoniana had better fit than those for non-resin-tapped trees. In the developed and tested regression models, except for leaf biomass and root biomass models, the remaining models achieved acceptable performance statistics. Models for stem, bark, and aboveground biomass performed best (models 4, 4, and 7). These models have critical applications in forestry management, providing scientific evidence for biomass estimation and management of Pinus massonianaplantations under resin tapping disturbance.