Influence of the tides on the wood properties of moon wood

For centuries, there have been traditional rules regarding felling times that are favourable for certain wood properties. These traditions often refer to different phases of the moon. This article presents an approach to scientifically explaining the relationship between the position of the sun and the moon at the time of felling and the properties of the wood. The moon and the sun create a tidal potential on Earth, which results from the gravitational and centrifugal forces between the celestial bodies. This tidal potential affects not only water masses, moors, ice surfaces, and parts of the Earth's crust, but also plant matter. To investigate whether the tidal potential at the time of felling also affects wood properties, a computer model was used to calculate the tidal potential for the location and felling times of an experiment conducted at ETH Zurich in 1998/1999. The values for some of the wood properties examined in this test correlate negatively with the tidal potential at the time of felling: the lower the tidal potential, the higher the values for the wood properties examined. The differences between the highest and the lowest values were 20% for the shrinkage of sapwood and 30% for the compressive strength of weathered sapwood, respectively, and are therefore relevant for practical use. Furthermore, this approach can explain the traditional “moon wood rules” that describe the position of the moon and sun. In the future, this approach and other open questions arising from it could be scientifically investigated in further studies.