Well, thanks to modern mapping, now we do. Formerly easy to hide and illegal activity like burning a bit of forest to get some farm land now stands out and we can track what happens or happened to bits of land. That's basically what the article is pointing out is actually happening. A few bits of information in there:
- Forest regeneration is slow but significant; up to 40% of forest thought to be lost over the past decades has in fact regrown. It's a slow process that takes up to 4 decades to fully restore bio diversity. But it's possible and happening at pretty significant scale.
- The whole process is basically driven by poor land management, ignorance, and incompetence. Farmers mismanage their soil, thus exhausting it and then burn more forest to solve their problem while abandoning their old land, which then starts regenerating if left alone.
- Mapping provides authorities better insight where this is happening or has happened and allows them to step up attempts to crack down on this to both protect regrowing forest and put a stop to new attempts to burn forests. Simply scaling up that effort could go a long way to fixing the problem. Farming by its very nature is very local. If authorities show up within weeks of you burning a forest to start growing stuff, it gets a lot more risky. Burning forest is the lazy option; it's only convenient if you can get away with it. Mapping can fix that.