Timber, even after being cut, is still very much a living material, and its behaviour is greatly influenced by the weather—a frequently discussed topic in the UK! Come rain or shine, hot or cold, treated or untreated, timber will react in various ways. It's natural for timber to crack, warp, twist, split, as well as shrink and contract in dry conditions, and swell and expand in damp conditions. These are normal responses to environmental changes.