In the past, open burning of wood or wood products was a common practice, in part because there weren't many options for disposing of waste materials. We now know that open burning can harm the environment by releasing fine particulate matter and other airborne contaminants to the air. The emissions produced by open burning can also have an effect on human health, particularly for those with respiratory conditions.
Today, we have more environmentally appropriate alternatives for disposing of waste materials, and so it is best to avoid open burning whenever possible.