I think it's really hard to burn a healthy tree. Water is good at controlling temperature. Even you use a blowtorch on a healthy tree. You will just make a black taint on it. And a big healthy have tons of water in it. Make it even more durable to fire.
To make a healthy tree burnable. You first need tons of heat source to prepare the wood itself so it is dry enough that actually burnable. But a healthy forest shouldn't have that level of heat source to make it doable (otherwise it will burn itself away someday, just like current situation of CA)
Prescribed burn here exists to remove the fuel, so it never pile up to the level that "Once it ignited, everything burns regardless of it is a healthy tree or what. And it burns forever because everything is burnable at this level of temperature".
To make a healthy tree burnable. You first need tons of heat source to prepare the wood itself so it is dry enough that actually burnable. But a healthy forest shouldn't have that level of heat source to make it doable (otherwise it will burn itself away someday, just like current situation of CA)
Prescribed burn here exists to remove the fuel, so it never pile up to the level that "Once it ignited, everything burns regardless of it is a healthy tree or what. And it burns forever because everything is burnable at this level of temperature".