When kittens-game begins, our only option to obtain wood is by refinement. As the game continues, we have access to woodcutters, and they pretty clearly are more efficient than refining (see this question "When are Woodcutters more efficient than refining catnip?").
Later on however there are many upgrades to refining, with bio labs being one quite late and substantial upgrade (an additional 10% efficiency per lab). I noticed that a farmer's base rate for catnip is 5/sec and a woodcutter's base rate is 0.075/sec. It seems to me that it is already more efficient to refine than to chop.
I'm not always paying 100% attention, so I believe it is still a good idea to have a couple of woodcutters so that production is in the positive. All the rest of my woodcutters should be farmers, right?
I'm new to the late game. In late-game, are woodcutters obsolete? At what point does refining become more efficient than woodcutting?