The trees didn't disappear all at once. Losing the forest took generations and even though the Mushroom People knew the foreigners presented a danger, they rarely acted to stop them. Sometimes the foreigners wouldn't even be in the forest. On the occasions when they'd load up their sleds and drag the long corpses down the mountain and across the valley to their ships, the People would indulge in the relief of a silent forest, quickly forgetting that the silence had only returned to them temporarily.
But ultimately the trees did disappear. Unhealthy species of weak, soft trees took their place. Or bushes that barely qualified as trees at all. Or, in places, little more than grass and mud and stink. The Mushroom People relied on the trees for they provided homes for the mushrooms, the trees relied on the mushrooms for they connected the trees in vast networks, and the mushrooms relied on the people for they knew the seasons of the mushrooms and would spread spores to the farthest reaches of the forest at exact