Vergleichende Untersuchungen über einige physikalische und technologische Eigenschaften des Kern und Splintholzes der mitteleuropäischen Eiche

Summary

On oakwood from 17 trees the properties density, swelling, compression strength, modulus of clasticity at compression, tensile strength, shear strength, impact strength, Brinell hardness, and wear, were investivated and statistically examined. A comparison of the property values leads to the significant result that sapwood has somewhat less density than the bordering heartwood. This difference is, however, greatly constituted in the fact that the old wood (near the pith) is heavier than the younger wood (near the bark). As the other physical and technological properties are correlated with the density of oakwood, the effect of heartwood formation was studied by the determination of these correlations. It could be demonstrated that by heartwood formation the following properties are changed to the same extent as would be expected by the stated difference in density: maximum swelling in radial, tangential, and longitudinal direction, compression strength, shear strength, Brinell hardness, and wear. In contrast to previous statements, sapwood shows somewhat less maximum volumetric swelling than heartwood. Maximum swelling parallel to grain diminishes with heartwood as well as with sapwood when density of the oakwood is increasing. As general result of the investigations it can be stated that between the most important physical and technological properties tested of heart- and sapwood of European oak there are no essential differences. Hence, for all purposes where natural durability is either of minor importance or is compensated by proper wood protection measures, sapwood can be processed.