The Abnaki, naturally being Earth-lovers, discover how to use methane from cow manure to power an engine. They then figure out how to hook it up the a device with wheels...and voila! They have the tractor! Since they have invented the tractor, they have make plowing much more faster and efficient. Also, the tractor makes carrying heavy loads much, much faster and easier.
By inventing the first tractor, the Abnaki Tribe shapes how their history will turn out.