: Dix, B.; Roffael, E.

Abstract
Poplar heartwood and sapwood of the clones of Muhle-Larsen and Oxford show distinct differences in fibre length and chemical properties. NSSC-pulps from sapwood are of higher degree of whiteness and tear resistance but of lower yield compared to heartwood pulps; however, no significant differences in the tensile and burst strength were observed between NSSC-pulps of heart- and sapwood. Strength properties of sulphate pulps prepared from both heart- and sapwood were significantly influenced by pulping conditions. Heartwood pulps are generally of higher yield and ash content than those made from sapwood. Definite differences in the degree of whiteness as well as in the strength properties between heart- and sapwood pulps were detected. Moreover, clonedependent differences in the properties of pulps from heart- and sapwood do exist.