Hearing that statement just made me extremely concerned for this place because a preserved forest wouldn't mean shit if the people preserving it wouldn't be there to witness it—but looking at it from a dark perspective, nature could simply survive on its own and the reason they needed to be preserved in the first place was because of us humans.
It could range from the need for space to build resorts or condo units to just simply needing firewood but yeah, I've said it many times before that if we just vanished or died right here, right now, the world would just thank us for it.
In any case, one might say that we could just simply encase part of the forest but that's practically impossible because it just extends for miles and as big or perhaps even bigger than Manila and it'd just defeat the purpose of it being a natural forest. However, that just might be one of my proposed solutions if these people wanted to keep the legacy of their ancestors alive.