Repel Wood

This spell creates a flow of energy in a direction the caster sets when the spell is cast. All wooden objects are then pushed away in that direction for the duration of the spell. Any wooden object greater than three inches in diameter that is fully anchored in place will resist the spell. Any wooden object three inches in diameter or less that is anchored will shatter, and its pieces will be pushed away. All affected objects are pushed at a speed of 40 feet per round. Any objects that are carried will push their bearer unless dropped or released. Any spear braced against the spell will shatter. Even magic items with wooden components are pushed away. Once the spell is cast, the path of the flow of energy is set and the caster does not need to do anything to maintain it.