Custom Villager trades based on biome

So I'm just curious, I'm creating a mod that overhauls the villager system, but for some professions such as a Lumberjack, I want the profession to trade a custom sapling/wood type depending on biome (So an acacia villager will trade Acacia Saplings/Logs). If you do have a custom procedure to do exactly that, then please reply to this with the procedure in a picture.