heartwood defined in 1951 yearheartwood - heartwood;
heartwood - Central mass of xylem tissue in trunks of trees, with no living cells (such as xylem parenchyma and medullary ray) and no longer functioning in water conduction but only for mechanical support; with its elements frequently blocked by tyloses and often dark-coloured, e.g. oak, ebony, impregnated with various substances (tannins, resins, etc.) that render it more resistant to decay than surrounding sapwood.
near heartwood in Knolik
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