Would an Army using a controlled fire surrounding an opposing army in a heavily forested area be an effective way to destroy said army?

Question

Imagine a scenario where Army A has received intel of the movement of Army B in a heavily forested area. Army A decides to spring a trap where in it sets fire to the forest encircling Army B, intending for the spread of it to boil Army B alive.

Having fallen for this trap and assuming conditions are palatable for the spread of fire, what tools would a readily equipped medieval army be capable of using to survive or reduce casualties? Would the same apply to a poorly prepared army? Are there any real world examples from any time period to draw from? Assume no substantial bodies of water nearby.

For future reference, please be aware that asking more than one question is literally a reason to close questions (Needs More Focus). Please focus future posts on just one issue, and be sure the post title and the question in the post match. Thanks. — JBH, Dec 23 '23 at 16:42
@DavidR : and how to prevent them from breaking out? If numbers are equal, they can concentrate all their forces at one point while you are spread out widely. Besieging and starving them out only works if you have a large numerical advantage. — vsz, Dec 23 '23 at 21:34
@Sphennings OK then, I'll vote to close all questions that ask how can someone reach X goal. Don't be surprised you have a huge list of pending questions to be closed, though. — Tortliena - inactive, Dec 25 '23 at 19:20
@Tortliena If a question is asking about in world decisions of a character or organization then it should be closed, regardless of the number of questions asked. — sphennings, Dec 25 '23 at 20:13
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@sphennings questions about strategy are explicitly on-topic. — M S, Dec 28 '23 at 16:54
@sphennings Capabilities of characters within a world and creation of groups of characters (like nations) are on-topic, but questions must focus on what is possible or likely to develop, and Similarly asking for techniques or strategies can be on topic (if insufficiently constrained close as too broad).. — M S, Dec 28 '23 at 18:02

score 9 · Accepted Answer · answered Dec 23 '23 at 06:18

Fire has been used as a weapon many times, as has forests. If done properly your medieval army is dead bbq. Their best recourse is to try and find a clearing and chop down everything around it. Which then leaves them as sitting ducks huddled together and easy to take care of. Or they can panic (most likely scenario) and run around like headless chickens and get slaughtered piecemeal.

One method where a forest was a weapon was used by the Gauls against the Romans. Shortly after the battle of Cannae a force was sent to punish the Gauls for aiding Hannibal and had to pass through a forest. In the Battle of Silva Litana the Gauls cut partway through the trees along the route then toppled them on the Roman columns which lost cohesion and were slaughtered ending with their commanders skull being lined with gold and used as a cup and apparently only a dozen or less survived.

Then the Battle of The Teutoborg Forest was a great ambush. Neither of these bothered with fire though. Fire was often used to herd people or animals towards a killing zone or trap. A good forest fire travels faster than a human though so unless trained to survive them it's unlikely your army will make it. Even trained fire fighters sometimes don't. The main problem is targeting the army with it. You can't light all around, that will create an already burnt area they can go into because fire will travel with the winds direction. And in fact this is how it's handled in forest fires, they will burn an area ahead of them and move into it hopefully before the fire behind gets them.

With the right conditions though the army will be toast.

score 2 · Answer 2 · answered Dec 23 '23 at 03:38

Counter-fire: Any large fire creates a current of air towards the fire. If you time things precisely, you can start a new fire in front of the advancing fire. The current of air pulls the new fire TOWARDS the existing fire, creating a safe (burnt-out) area

Just make trenches: Make a "safe island" by removing existing trees, bushes etc. and possibly digging a trench.

score 1 · Answer 3 · answered Dec 24 '23 at 05:09

No, but not for the reason you would think. Medieval armies follow roads and these roads are for all intents and purposes the only way for an army to know where it is and where it is going. the Roads serve as a Fire break, and as the roads must be wide enough for both their wagons and their marching formation it is unlikely for the fire to cross the road.

It might be possible to light two fires in such a way to pincer them but that is well beyond the capabilities of a Medieval army. The Romans might have been able to attempt something on that caliber, but they have no reason to do so; Romans for most of their history have the best army around and they can just beat you without the circumstances.

All this to point out one more subtle point a forest isn't a strong point for an army, armies with their large quantities of men are hungry. Forests cannot feed them in sufficient quantities for it to matter. This means that if an army is in a forest it is moving though it temporarily. Besides armies only fight in this period to raid or to deliver a siege. Figure out which you opponent is trying to do and if you can create a plan to stop them you'll will win the conflict.

Would an Army using a controlled fire surrounding an opposing army in a heavily forested area be an effective way to destroy said army?

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