Herb bonus for trees.

I'm not entirely sure that it's distance based within your homestead. I had assumed that it just meant "near" as in "within the confines of the homestead" instead of near to each other with a fading effect if you put it across the homestead. To be fair, it should have the same effect as the other boosting items, so lemme double check the success rate of my refining when I put my furnace across my homestead from its booster, as opposed to right next to each other.