After updating to build 100 of botania(Congratulations on this milestone, Botania has been a wonderful mod to use) , a strange crash occurred. While I have tweaked biomes on my map a bit(Adding in a desert, swamp, tundra, and jungle), there was nothing here apart from vanilla biomes.

Here is a link to the crash log: http://pastebin.com/C9kD24wm

Minecraft version 1.7.2
Botania version 100
Forge 10.12.2.1147

Doesn't seem like this is my issue. Probably has to do with your biome tweaks.

Strange, only tweaks I have made have been long standing and a simple edit of "This area is now X biome". I'll look into it a bit more, but this has only occurred once after updating botania.