Relationship of Black Walnut Wood Color to Soil Properties and Site

This investigation is the first to provide information for any species on the magnitude of quantitative wood color differences between individual trees and between groups of trees at specified locations. It is also the first to report on the effects of specific environmental factors on wood color. Larger differences were found between black walnut (Juglans nigra L.) trees in heartwood luminance (lightness) than in dominant wavelength (hue) or purity (percentage of principal hue). Indiana-grown walnut heartwood had higher luminance than Missouri-grown. The relationship of heartwood color to soil properties was greater than it was either to tree age or to diameter-growth rate (rings per inch)