Nature magic has the wonderful ability to be beautifully simplistic in its execution while being stunningly vast and complex in its scope. The magic might be tied to plant life, to the seasons and changes of season, to the weather, or to all of these things together.
The effects of celestial bodies are so subtle that we often don’t realize them in our daily lives, and yet they are there. If you live on or near a coast, you are probably more aware of them because of the daily ebb and flow of the tides, which are caused by the pull of the moon’s gravity on the earth.
No matter what type of magic exists in your world, or how it is utilized, knowledge of it will be accumulated and compiled. Magical knowledge is often treated a bit differently than academic knowledge in general, since in the wrong hands it might be very dangerous.