Herb bonus for trees.

All right, I just checked, and it looks like I was grossly mistaken. Based on my check, it looks like anything that has a boosting effect must be within one tile (either diagonally or horizontally) of the item it is affecting. That means that if there is a tile of space between the two, they won't be boosted. So, here's a diagram, if I can get it working:

+-+-+-+-+-+-+-+-+-+-+-+
| | | | | | | | | | | |
+-+-+-+-+-+-+-+-+-+-+-+
| |i|i|i|O|O|O|i|i|i| |
+-+-+-+-+-+-+-+-+-+-+-+
| |i|i|i|O|O|O|i|i|i| |
+-+-+-+-+-+-+-+-+-+-+-+
| |i|i|i|O|O|O|i|i|i| |
+-+-+-+-+-+-+-+-+-+-+-+
| |O|O|O|X|X|X|O|O|O| |
+-+-+-+-+-+-+-+-+-+-+-+
| |O|O|O|X|X|X|O|O|O| |
+-+-+-+-+-+-+-+-+-+-+-+
| |O|O|O|X|X|X|O|O|O| |
+-+-+-+-+-+-+-+-+-+-+-+
| |i|i|i|O|O|O|i|i|i| |
+-+-+-+-+-+-+-+-+-+-+-+
| |i|i|i|O|O|O|i|i|i| |
+-+-+-+-+-+-+-+-+-+-+-+
| |i|i|i|O|O|O|i|i|i| |
+-+-+-+-+-+-+-+-+-+-+-+
| | | | | | | | | | | |
+-+-+-+-+-+-+-+-+-+-+-+

In this, the X would be the location of the boosting item, and the i and O would be the location of anything to be boosted. (i and O were both used to help make it at least a little more readable) The blank spots are areas where nothing would be boosted. Keep in mind, this is assuming that both the boosting item and the boosted item are 3x3, which I'm unsure is true for everything. What I'm trying to say is that the items have to be directly touching, I suppose.