Application of Pilodyn method in predicting the basic density of standing trees of Pinus massoniana Large-diameter Wood

The resistance value of Pinus massoniana large diameter wood at a breast diameter of 35 years was measured using a Pilodyn instrument. The wood samples were divided into three age groups: inner(0～10 years), middle(11～20 years), and outer(21～35 years). Wood cores were collected in the north-south direction, passing through the pith, using a growth cone. The study analyzed the change in wood basic density in each age group, examined the relationship between Pilodyn measured values and wood basic density, and established a Pilodyn prediction model. The results indicated that the basic density of P. massoniana large diameter wood initially decreased and then increased from the pith to the outside. In all age groups, there was a significant or very significant negative correlation between Pilodyn measurements and wood basic density. Notably, the correlation coefficient(R) between wood basic density and wood basic density in the 21～35 year age group reached -0.807. The correlation progressively weakened from the outer to the inner regions. Furthermore, there was a very significant positive correlation among wood basic density in all age groups. The regression analysis yielded a coefficient of determination(R²) of 0.4315 for the regression equation established by Pilodyn and the average wood basic density across all ages. The regression equation for the wood basic density of the 21～35 year age group had the highest R² value of 0.6535. These findings contribute to the understanding of the Pilodyn method's application in the rapid and non-destructive testing of wood basic density in large diameter P. massoniana wood.