Most people grossly underestimate how wild and pretty much lawless inland rain-forest regions are in the Brazilian state of Amazonas. There are small pockets of settlements everywhere but except for Manaus there is very sparse infrastructure, Police will take days to get somewhere by boat, Healthcare deep in the forest is pretty much a death sentence if you happen to need urgent critical care. You have people that have never been registered with social security, etc.
My point is that having a piece of paper saying that a specific rosewood tree belongs to IKEA or <NGO> would mean nothing, by the time you try to enforce this, the tree would have been fellen, cut, and shipped on a boat to the highest bidder.
If you want actual change in the region you need to develop the local economy with jobs that allow these people to be productive in a way that is somehow more profitable than the existing illegal activities. But the practicalities of this are much harder to implement then simply blank buying forest land.