Change Biome

You permanently change the biome of a 25 mile area around yourself. You must be outdoors to cast this spell, and create a nexus that anchors the focus.  This nexus is typically a detailed representation of the new biome, and it must remain intact during and for a period after the spell is cast (see below).

When you cast the spell, you change the biome to one of your choice (ie, desert, forest, grassland etc).  This does not change the underlying terrain.  Over the course of 5d6 days the new conditions take effect, causing changes in weather conditions, vegetation and the distribution of wild animals. 

While the change is still taking effect it can be paused by disturbing the nexus, or stopped mid-change by destroying the nexus (AC 10, immune to damage other than disintegrate). Once the change has taken effect, only another casting of this spell, the wish spell or divine intervention can reverse the changes.