Choppa
Attachment. Weapon.
"Attach to a target unit in your battlefield.
Attached unit gains PP."

Questions:
1) What happens if the attached unit is Forced Marched to the Kingdom Zone ? Does the attached unit still gain two power from the Choppa ?
2) Does the Choppa provide power to collect resources or it only works during combat ?

The unit only has to be in the battlefield when the card is attached, if it's subsequently moved it retains the additional power since it's still attached.