Figured wood occurrence in Acer pictum is related to tree form

Figured wood in Acer pictum is valued for furniture and musical instruments, yet its occurrence remains poorly understood because reliable assessment is difficult without felling trees. This study examined the relationship between the occurrence of figured wood (wavy and birdseye) and tree characteristics in 60 A. pictum trees within a 16.8 ha natural forest in northern Japan. Boards 30 cm in length were obtained from logs cut 3 m above ground, and the proportion of figured wood (PFW) was quantified. Structural equation modeling (SEM) was used to evaluate direct and indirect effects of stem crookedness (SC), fork height (FH), annual ring width (ARW), and basal area on PFW. Although 87% of trees exhibited figure, the mean PFW was low (7.0%, SD = 9.8%), and only 5% of trees showing PFW greater than 31%. Contrary to expectations that larger trees produce more figure, PFW decreased from pith to bark. SEM indicated that SC and FH were the strongest predictors of PFW, whereas ARW showed no significant effect. These results suggest that silvicultural interventions, such as thinning, may influence figure formation primarily through alterations to stem form rather than growth rate. We argue that retaining atypical tree form may improve the future commercial value of hardwood forests.