Some good tips! It sounds like forest-burning is a bit random for you, when it ideally shouldn't be.
In case you're not aware, you can set up toxin scrubbers on top of burnt buildings. With that, you can afford to burn down more land than is minimally necessary (since it's hard to start multiple fires), and once you have achieved the required amount of forest, turn the remaining ash back into greenery with toxin scrubbers. That also can get you some additional land for beehives, if you need it.