Provenance variations in wood traits of Larix kaempferi (Lamb.) Carr. and their relationships with growth parameters

Understanding genetic variation in wood traits and their relationships with dynamic growth is essential for the genetic improvement of forest tree species. This study investigated genetic control of 15 wood traits and their associations with dynamic growth patterns in Japanese larch ( Larix kaempferi (Lamb.) Carr.), using a 22-year-old common garden experiment in Hubei Province, China. Through analysis of 450 trees from 84 families across six provenances, we demonstrate that growth parameters derived from logistic nonlinear models effectively capture temporal growth dynamics. Linear mixed model was used to estimate the genetic parameters of traits. The bivariate mixture model and Pearson correlation analysis were used to estimate genetic correlations of wood traits and growth parameters. Tracheid dimensions showed high genetic regulation and exhibited positive correlations with asymptotic growth parameters of tree height and diameter at breast height, height growth rate displayed negative correlations with earlywood tracheid width. These findings establish that growth parameters effectively characterize ontogenetic growth patterns while tracheid size is closely linked to these developmental processes. The demonstrated connections between tracheid size and growth parameters provide new breeding objectives in L. kaempferi breeding programs.