Drying and weathering behaviour of Norway Spruce (Picea abies Karst.) wood felled according to moon phases
2003
Zuercher, E. (Hochschule fuer Architektur, Bau und Holz, Biel (Switzerland). Fachbereich Holz)
In addition to a general study with statistical analysis of the relation between felling date (chosen in function of the lunar cycles according to forestry traditions) and the main physical properties of wood, the present publication deals in detail with some aspects of the wood-water-relation, and presents the effects of a prolonged weathering on samples issued from the main trial. For both sapwood and heartwood, it appears that in the second half of the tested period, the proportion of free water (easily extractible) compared to the bound water (which in association with the cell wall causes shrinkage during the drying process) varies systematically and significantly, depending on the felling date. The physical effect of the weather exposure apparently did not cancel out the significant differences initially observed: whether in a humid state as conditioned or oven-dried, a systematic alternance in the relative weight of the samples remained visible (for all six dates in sapwood samples/ only for the second half in heartwood samples). The «lunar effect» on compression strength of weathered samples remained only in the second half of the experimental period. The relative deformations of the compression-tested weathered samples showed a systematic variation in sapwood only. The decay symptoms (fungi, moulds, lichens) were clearly reduced on sapwood samples from December and January felling dates at waning/descending moon. These results are compared to similar studies and placed into a scientific context in accordance with the initial hypothesis.
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