Lunar rhythms in forestry traditions - Lunar-correlated phenomena in tree biology and wood properties

For more than 2000 years, certain forestry practices and rules regarding tr ee felling have been carried out in observance to Moon cycles. A general re view of the different types of rules followed (known in Europe and on other continents and stemming from both written sources and current practitioner s) shows that special timber uses are mentioned in relation to a specific f elling date which supposedly ensures advantageous wood properties. These empirical forestry traditions apply to a range of wood uses as divers e as building timber, shingles, wooden chimneys, fuel wood, resonance wood for harmony tables of violins, cheese-boxes, barrels and ploughs. In each o f these cases, felling at the "right date'' is thought to be an important f actor to ensure the required properties of the product. Moreover, the rafti ng of timber used to be limited to certain days of the Moon cycle, when the water was supposed to carry the wood in the best way. The second part presents scientific studies concerned, on the one hand, wit h "Moon phases'' factor. They deal with elements of tree biology such as ge rmination and initial growth of tropical trees (where strong and systematic variations and their complicating aspects have been observed), insect atta cks on trees and reversible fluctuations of stem diameters. On the other ha nd, some works concentrate on wood properties and the relation between wood and water. They deal with the durability of wood, with systematic density variations after kiln-drying and with variations in the compression strengt h of the corresponding samples. An overview tries to find a common link bet ween empirical practices and the scientific results.