Longitudinal contraction of reaction and opposite wood during drying process
Reaction beech wood has different anatomical and also chemical characteristics than normal (opposite) wood. The difference in density is conditioned by percentage of G–layer. Fibers cells in reaction beech wood have a different cell wall structure and a different chemical composition, as well. Longitudinal contraction was noticeable in reaction (tension) samples, where it was several times higher, what could be expected considering the physical properties of reaction beech wood. Our measurements confirmed that drying time has remarkable effect on longitudinal contraction. Higher longitudinal contraction was measured in temperature 60°C and 120°C, which had almost identical drying time. The issue of variability initial moistures did not affect the drying process and samples reached approximately equal final moisture content. Reaction beech wood is a very serious problem in nowadays wood production.