Intrafamily variation of grain spirality in a control-pollinated family of hybrid larch

Abstract

Intrafamily variation of grain spirality was investigated in 210 individual trees of a control-pollinated family of hybrid larch (Larix gmelinii var. japonica × L. kaempferi) at age 12. Grain spirality at each growth ring boundary was measured by applying the splitting method to specimens obtained at around breast height from the sample trees. Mean and maximum spiralities were 0.96º ± 0.58º and 2.72º ± 0.78º (mean ± standard deviation), respectively.These results indicated that, among various larch populations, the investigated family had low-spirality and that intrafamily variation was large even among full sibs. The analysis of interrelationships among various parameters of grain spirality revealed a relatively high correlation between grain spirality at the outermost ring and mean spirality, indicating that log sorting for grain spirality can be achieved when outermost ring spirality can be measured on the logs. In conclusion, the combination of the genetic improvements obtained via family selection and log sorting to select better individual logs from each family is a promising approach towards a more efficient wood utilisation and sustainable forestry development.