In Massachusetts, open burning is generally allowed Jan 15 – May 1 between the hours of 10 am – 4 pm for brush/forestry debris, with permits from the local Fire Dept. Local rules override general state laws, so always check with your town. State fire wardens determine each day whether conditions are safe for open burning. Weather and air quality can change rapidly, especially in the spring, and fire departments can rescind permits when that happens.