the Zombies eat tree because the zombie apocalypse began in a laboratory where scientists tried to genetically modify a virus. And while doing that they Also added Beaver genes to a deadly virus to make it more water resistant. The next night a scientist sneaked into the facility and stole one virus to sell it to a northkorean terror group. This one virus was the one with the beaver genes. Unfortunately though the terrorists immediately used the virus and set it free in New York city. The virus spread instantly and after a short while the whole world was infected. Unfortunately the Virus had the side effect to reawake the ones who had died to it. These People are the Zombies and the beaver genes caused them to eat all the trees they would find. Thats why the tree in the game is the last one on earth and the zombies are trying to get this last tree now too.
Thanks for the inspiration my game has LORE now lol