Area III, this time I failed. Didn't expect there to be a change of buildings that can be planted on stage II. I think the mission briefs needs to be improved in order to prepare player of what to comes later in the stage.
Why yes I do. Focus on building a huge green area first, connected to a tree. Build a bee hive on top of the tree, which produces a field of flowers. Burn it down. Then after all that lefts are ashes, build some arbotorium, only some, don't cover the whole area with it, left some space to build the bee hives. I recommend you to build the arbotorium in the middle of the burned area so that you can surround it with the bees.
To recover burned down area, you can just put a toxin scrubbers on top of burned down buildings. But remember that it must be near an energy sources aka the turbine.