Explanation: Wood is a porous material and will absorb moisture from the air. Moisture is attracted to the walls of the tubes that make up the wood. Wood will only decay if it is in contact with the ground or wetted by an external source of moisture, such as rain seepage, plumbing leaks, or condensation. Dry wood will never decay. Also, the drier the wood, the less likely it is to be attacked by most types of woodinhabiting insects.