The humans lived their life and so did the cloud people, eventually the people forgot about the cloud people and began to cut down trees for their homes.
The sky people were very angry with the people and created "natural" disasters in hopes that the people would stop cutting down their homes.
But that did not stop the people from destroying the cloud peoples homes, they just kept building and cutting down the cloud peoples homes.
The cloud people tried to stop the humans, but it only made it worse.
Quit destroying our homes!!!
Their attempts only scared the humans into war with the cloud people
The cloud people only saw one way to fix the problem, they turned half of the human population into trees causing the war to stop and when the surviving people saw what had hapend they never cut down a single tree again