Variation in Heartwood and Sapwood Properties Among 10-Year-old Black Walnut Trees

Abstract

Ten-year-old black walnut trees from a half-sib progeny test were sampled for a study of heartwood and sapwood specific gravity in relation to color properties and total tree height. Average wood specific gravity for all 320 samples was 0.47. Sapwood specific gravity averaged 5 percent lower than heartwood specific gravity (0.46 and 0.48, respectively). Heritability of wood specific gravity was 0.35 for heartwood and 0.54 for sapwood, the lower heartwood value suggesting a greater environmental influence on heartwood formation. Heartwood specific gravity was negatively correlated with heartwood color and was positively correlated with total height. Sapwood specific gravity was not correlated with total height.