Publication Date:
2000-02-29
Description:
Summary In the present study, the biological, chemical and mechanical wood properties of “Wulstholz” as a response to mechanical stress of spruce trees (Picea abies [L.] Karst.) were investigated. “Wulstholz” is formed locally on the compression side of overstressed tree trunks after slip planes were initiated. It is characterized by an increased xylem production leading to bulges. The S2-layers of “Wulstholz”-tracheids are thicker than the corresponding cell wall layers in normal wood, and the cell lumen diameter is significantly reduced. The tracheid length decreases gradually from an average of 4 mm to 2.5 mm compared to normal wood, and the tracheids conspicuously are shifted against each other longitudinally. “Wulstholz” contains a higher concentration of lignin than normal wood, whereas the concentration of glucose in the hydrolysates is reduced. The hemicelluloses-concentration, particularly the mannose-content, is significantly higher compared to normal wood. The compression strength and the modulus of elasticity, despite a higher density, are significantly reduced in “Wulstholz” in comparison to normal wood. But due to the specific anatomical and chemical properties, “Wulstholz”-tracheids can be deformed and compressed considerably without fracturing. The investigations demonstrate that “Wulstholz” can restabilize wind-exposed trees.
Print ISSN:
0018-3830
Electronic ISSN:
1437-434X
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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