Knotty alder can be cheaper than clear alder boards, but the knots will pose certain problems for cutting and creating a smooth surface. One danger that should be considered when using knotty alder is that saws can respond unpredictably when they come into contact with knots. Sudden jumps or directional deviations can occur while cutting because the knots are significantly more difficult to cut than the surrounding board surface. Also, knots can unexpectedly fall out of a board and create a hole. While knotty alder is great for achieving a rustic look, it should be avoid in all other circumstances.