I wonder if a wood powered tractor for farming would be more practical than a wood powered car for transportation
Historically, they weren't that common, as large-scale use of wood gas was mostly a thing in Europe during WWII, and during that period continental European agriculture was still mostly horse-driven. After WWII when agricultural mechanization really picked up, fuel was again available so there was no big motivation to put up with the disadvantages of wood gasifiers.
A tractor can certainly work well on wood gas.