Most states do not specifically prohibit ownership of tracers.
All states specifically prohibit reckless use of tracers.
Most states specifically prohibit casual use of tracers.
To my knowledge, you are free to shoot them on private property.
So these statements are to characterize my opinion if you are caught shooting them, you'll probably be told to stop. At the most, a ticket and confiscation. They might even confiscate if you possess them in a prohibited area.
I have been shooting tracers from many, many years. No one has ever said anything to me about it. But I don't shoot tracers where they are specifically prohibited either. Never during fire season and never in areas prone to a fire hazard.
I have never started a fire. But I mostly shoot in the air...long range. Yes they do burn, even when they sit there and burn for awhile, they usually go out. Most of the time they do not start a fire. You must always be prepared to put out a fire if you shoot tracers. Unless you shoot in a dry, parched grass/leaves, you don't have much to worry about. Tracers fires don't usually start in the dirt and the rocks. Better to shoot tracers when it cool or moist.
But I know tracers will start huge fires because we started them everytime we shot them in the military on the range. If you shoot tracers, be prepared to take responsibility. Check your local laws.