You first need to enter the volcano, and when you are on top you need to walk to the edge of the volcano and then you will see a gray colored path of grass, and if you follow it, it will bring you to the biome, plus you can't get there with a car so you'll need to walk.
In the middle of the biome lies a river of lava, so if you want to get over it you will need to use a long wooden plank. If you jump in it you will die just like in the Volcano.
There also is a tiny path leading to a higher lying piece of land, which you will also need a long plank or a piece of wood to get to the top for harvesting.
The biome consists of shale grey rocks with grey grass where the Fanon:Volcano Rock Wood grows, and a ledge where the biome opens into the inside of the Volcano. It is a semi-biome so it is small, but it can grow more than one tree.
Since this biome is open to the lava river, if you get too close you would slowly lose health from the particles coming from the river.
The Fanon:Volcano Rock Wood is the only type of wood that grows in this biome. It is assumed that every other type of wood burns up and becomes ashes, thus giving the name of the Ash Delta. Only the Fanon:Rock Wood survives this biome, thus adapting from the heat to become Volcano Rock Wood.