For a sizable factory, massive spaces must be dedicated to renewable energy, which means obliterating lots of pests. And building the renewable infrastructure--mines, crude pumping, transit, smelting, refining, manufacturing, landfilling lakes, bot deployments, defense--are massively expensive and polluting. By comparison, nuclear (or even coal!) is much easier on the wildlife.

If the trees didn't look so depressing in this game, there would be motivation for reforesting (beyond reducing pest problems) - making your factory look nice, with an ordered mix of nature and high-tech industry.