Lower levels of CO2 are also a signal for the
mycelium to create
fruit bodies. Again, in nature when the
mycelium reaches the outside of the dung pile, there is much more fresh air than inside the pile. The more (clean) fresh air you can get into your
fruiting chamber the better, so long as you are able to keep the proper level of humidity. Also, some contaminants thrive in stale air with high CO2 levels, so FAE is also important for avoiding conditions favorable to some molds and bacteria.