Elisabeth Windeisen

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Thermal treatments of beech wood with different temperature loads on the wood cause characteristic changes in the chemical composition. The determination of specific changes was carried out by means of suitable methods, both wet chemical and instrumental analyses. It could be confirmed that in addition to the degradation of polyoses, lignin, known as the(More)
Material and methods Investigations were carried out on 20 cultivated larch trees (hybrid test area ‘‘Bomigrain’’ forestry district Rothenbuch) selected according to phenotypic criteria. These trees formed the basis of a new breeding program to improve the growth, stem shape and especially the wood quality of larch trees. Two parts of a stem disc taken from(More)
Quality assessment of thermally modified spruce (Picea abies (L.) Karst) and beech (Fagus sylvatica L.) wood and of the corresponding reference samples was carried out by means of non-destructive FT-NIR spectroscopic measurements and PLS regression. Oven-dry and basic density as well as MOE and MOR determined by 3-point bending tests were evaluated. The(More)
Friction welding is a new technology in the course of which wood pieces are subjected to circular or linear movements in a welding machine. The wood in the contact zone is heated and melted. Aiming at a better understanding of the thermal alteration of wood and the formation of a viscous layer acting as adhesive, the thermally changed material was taken to(More)
To test the effects of calcium on wood formation, Populus tremula x Populus tremuloides clones were supplied with Hoagland solution modified in its calcium contents. Energy-dispersive X-ray analysis (EDXA) revealed an increase in calcium in the phloem, the cambium and the xylem elongation zone with increasing Ca(2+) supply in the nutrient solution. Using(More)
The lignin distribution in cell walls of spruce and beech wood was determined by high-voltage transmission-electron-microscopy (TEM) in sections stained with potassium permanganate as well as by field-emission-scanning-electron-microscopy (FE-SEM) combined with a back-scattered electron detector on mercurized specimens. The latter is a new technique based(More)
Im Rahmen einer größeren Untersuchung besonders wertvoller Hochzucht-Lärchen war eine direkte Korrelation zwischen dem Extraktstoffgehalt und der Dauerhaftigkeit festgestellt worden. Zur weiteren chemischen Charakterisierung wurden die beiden Lärchenbäume mit dem niedrigsten sowie dem höchsten Extraktstoffgehalt herangezogen und die Hauptverbindungen(More)
Relevant parameters for the hardening of acid catalyzed and water based adhesives (e.g. MUF) are certain wood characteristics such as water absorption capacity, pH-value, buffering capacity towards acid and extractive content. This study was performed to characterize these parameters for beech (Fagus sylvatica L.) and ash (Fraxinus excelsior L.) with and(More)