1. The goods and services forests provide should be incorporated into economic assessments as well, not just the value of their board feet of lumber.
What is "board feet of lumber"?
2. And here's another thought: forests that are owned by the communities that actually live in them tend not to be cut down. So local ownership could help forests survive.
"live in them tend", why use "them" instead of "their"? What's the meaning of it?
3. So what could be done to save the 13 million plus square kilometers of untouched forests?
PLUS here is equal to MORE? Right?