The plants and trees are living organizations and contain fluids. These fluids - as all the materials - follow the same gravity laws. However, when there is full moon the gravity force from the moon is so strong that makes the fluids in the plants move upwards, within the plant. If we choose this period of time to cut a tree in order to produce furniture, then the pieces of wood we collect will have fluid within them. This causes them to rotten very quickly and if furtiture is produced from them, it will not be stable. Whereas, if we choose to cut trees at some other time, when the gravity force from the moon is not strong, then the fluids in the plants will not be forced to move upward, since the only power forced upon them will be the gravitation from the earth. So, if we collect wood at a time when the gravitation from the moon is weak, then the pieces will not contain much - if any - fluids, therefore, they should not rotten and will be safe for use.
This submission was not accepted into the wiseGEEK Writing Contest because it does not meet the minimum length requirement.