Iyo/Firewheel is an Official GemStone IV Document, and it is protected from editing.
As recorded from a speech given by the Iyo Crafter Uhlen:
Amongst the Iyo people, the firewheel trees are considered to be the heart of the Isle. The grove in which they flourish is unlike any other area on the entire island, and Aeydor himself has acted in the past to prevent it from being stolen away.
Firewheel trees are never harvested in the normal way. No Iyo would dare to take an axe to the heart of our home, after all. And any trees that fall naturally are left to return to the soil, nurturing the saplings which will come after. However, from time to time the storms that rage across the Isle will send fire from the skies and fell a firewheel tree. These trees are what are harvested and shared amongst the greatest craftspeople of the Iyo.
Weapons and instruments wrought from these firewheel trees, imbued with the fire of the sky, contain a piece of the heart of the Isle. Instruments forged from this rare wood are of the highest possible quality, and weapons contain both the innate fire of the tree and the might of the storm.
Firewheel is precious to the Iyo, and is always to be treated with respect. Only the greatest craftspeople are given access to the wood for crafting purposes, and to receive a gift of a firewheel weapon or instrument is the highest compliment that the Iyo can confer.