Since this doesnt really works with "Dryad strikes back" i will put into a different thread.
20x20 area from where Dryad has spawned can gain a temporarly quality boast random from 1-25 with double deplation rate when harvesting the stuff. This affects foragables, soil, and trees, but does not affect non forest stuff like grassland, moor, rock, stone, etc..
Spotting Dryad does not mean area right where he is walking is booasted, it indicates you are probably near a temporarly booasted area since its based on his spawn tile. =P
Could implement other "guardian" type creatures for the sea, mountian, etc that offers same type of temp boast since they are usualy a rare sighting.
If you are lucky, it might even spawn one day ontop of your good node boosting quality to something amazing for a few minutes, etc.