Physical Characteristics of Seasoning Discolorations in Sugar Maple Sapwood

摘要

Gross and microscopic characteristics of sugar maple sapwood that has undergone color changes and discolorations of a chemical nature during seasoning are described and illustrated. The discolorations include reddish browning, interior graying, and sticker staining. The form of the colored matter in ray and axial parenchyma cells of reddish-browned lumber was mostly amorphous and that in the parenchyma cells of interior-grayed and sticker-stained lumber was mostly plasmatic. Quantitative values for color, of the International Commission on Illumination System, are given for reddish-browned and non-discolored material. Color variation usually was associated with variations in kiln-drying conditions. Discolorations such as interior graying and sticker staining were associated with slow air drying under mild conditions or improperly controlled kiln drying. Fungus infection was found in some specimens with interior graying.