[SunkenCiv]

The main obstacle has been Clovis-first-and-Only, which requires that the Americas were settled just once, fairly recently, and from north to south.

[SunkenCiv]

[chesley]

I read about this in the book 1491, recently. I forget who wrote it, but it was quite an interesting read, if a little bit PC.

[blam]

Rainforest Researchers Hit Pay Dirt (Farming 11K Years Ago - South America)

[Dustbunny]

Slash and burn was a high temperature fire that emitted a lot of gas and didn't add much to the soil. Slash and char was a much lower-temperature, smoldering method that added more carbon and organic material to the soil. Practitioners likely burned vegetation while it was still green, resulting in a slow burning fire, then added more wet, green vegetation to keep it that way.

Guess they found a book on how and why to burn and char. /sarc