Does wifi affect the environment?

It probably does.  Everything mankind does eventually affects something, either positively and often negatively.

Hard for me to imagine with all these radio air waves floating inside earths atmosphere, that it doesn't have some kind of effect. That said ...read on ---

Wifi and Electromagnetic fields

Andrew Goldsworthy. Oct. 2008

We are constantly being misled by elements of the mobile phone and electronics industries (who have huge vested interests in the infrastructure) into believing that the pulsed microwaves used in cell phones and Wifi are harmless. Their sole justification for this is that the radiation is too weak to generate significant heat when they are absorbed by living tissues.

http://sunilkhemaney.wordpress.com/2008/11/02/how-wifi-and-electromagnetic-fields-influence-body-chemistry/

I think so... Although I don't think it has that much effect to our environment.

"The research, which took place in the Dutch city of Alphen aan den Rijn, found that the radiation from Wi-Fi networks could have an adverse effect on nearby trees and plants. The study, which went on for three months, found that trees near to Wi-Fi access points showed increased damage, cracks and discolouration, as well as slower growth and delayed flowering, compared to trees away from the Wi-Fi networks. These effects were found on trees 50-100cm of a 100 MW radiation source." - skillstrain

yes..i think