Parenchyma cells of maple wood may live for more than a century though a considerable proportion die earlier. A few cells succumb each year making "heartwood" formation gradual. Post mortem deposits, primarily in the parenchyma cells, account for the deepened color of older maple wood. The pH, water content, and mineral content of the wood do not change appreciably with aging. Maple wood often becomes deeply stained. The stain is due to deposits in the parenchyma cells which, if killed before senescence sets in, produce a post mortem deposit which is darker and larger than that produced by cells dying of old age. Stained wood is distinctly alkaline and contains substantial amounts of minerals which accumulate in the stained region. These regions also have a higher moisture content than normal wood. The consistency with which stain is produced in advance of spreading decay fungi suggests that staining and the related chemical changes exert a considerable influence on decay in sugar maple.