Oh hey, its the university I went to! I discovered this game through itch.io, so I was rather surprised to see the emblem. Played a couple of rounds, I got neutral and then physician for my runs. I dont seem to get when a forest tile will spawn more trees, so I can´t build the cleansing forest of my dreams. My preferred strategy in my own words is removing the new growth in the early game for cash, which I spend on increasing the number of farms to be on par with the population. Removing new growth has the benefit of keeping those new farms safer, and this gives me the money to cleanse the land and even plant forests in the later game. I only used chicken culling once, since it really hampers the money generation, and the dead population regenerates so fast. I will try some more maps to check if I can get a more forest based playstyle if I have less mouths to feed
Currently when you end your turn, each forest that isn't "mature" (has the full set of 4 trees on it) either has a chance of spawning a disease OR of growing a new tree.
Once it's a full mature forest, it won't spawn disease, and you have to weigh up if you want to cut down a tree to get more money, but take a chance that disease may spawn from the empty spot.