Knowing java is a bit of a pre-requisite for Modding. Googling the relevant part of the error
Will probably tell you what you need to do. By method signature I mean the name, parameters, keywords (access / static / final - public in your case) and return type (void in your case). Did you change it at all?
Does the class that you’re extending provide that method?
That tells you the problem in plain English. Did you change the method signature? Did you copy /paste the code from somewhere else? If you did the name of the method could have changed
World gen has changed a lot over time, I think if you want to have mod that provides this your best bet would be to grab the world datafixers from all versions & condense them
Can you post your code as a GitHub repository? It will save you from losing your work if you accidentally delete your entire project (this is actually relatively common) and will allow other people to view and review your code
About the obfuscation
Notch - obfuscated name
SRG - stays the same between versions, named after Searge who invented the system
MCP - deobfscated, translated from SRG with mappings, can change between mappings.
A great site is http://mcp.thiakil.com/
Your log should be telling you the errors (FileNotFound, MissingVariant)
https://github.com/Cadiboo/Example-Mod/
Cubicoder’s tutorials are pretty good, there are also links in the README of that repo
Write to NBT - write your data to a NBTTagCompound for serialisation (saving)
Read from NBT - read your data from a NBTTagCompound for deserialisation (loading)
There are a lot of conventions and practices that are unique to modding, most of which are outlined in the forge docs. Other than that, it’s just java. You should probably learn about Reflection because a lot of minecraft code isn’t directly accessible. You can use Forge’s ObfuscationReflectionHelper or ReflectionHelper to easily deal with that stuff.
How does the apocalypse work? If I were you I would subscribe to the event that fires when a chunk is finished loading from file or a new chunk is finished generating and I would check the surface of the chunk for blocks that have a material of leaves/vines and put fire in neighboring air blocks.