Human have set life time and removing chakra also shorten that time. No children will be born and the tree existed before Humans is get its power from the Universe it self in Nature chakra.Please read the below scan. The Shinju uses humans as a power source and keeps them alive like in the Matrix movie, if you ask me. Literally they are all slaves to the Genjutsu but the Shinju will never let them die which would make the whole technique's purpose void.
You must be registered for see images