Actually, trees and plants communicate with one another so that they can protect themselves from disease and insects. I remember reading that a tree which gets infected with a disease sends out some type of signal to other trees and they begin to take necessary steps to lessen the effect or prevent it on themselves....chemical warfare I believe.
I don't know how true this info is, but I do remember reading about it in some scientivic journal or other........so..........
Remember, plants and trees are living things.....quite different than what we would consider "living"......the reason for pain is to alert the body to illness or injury so that you can do something about it. I guess it's the same with trees and plants. They need to know there is something wrong so that they can take action against it if possible. Weither or not it's a conscience thing...anything living needs to be able to protect itself so that it can continue on.
Of course.....I'm not about to run out and hug my trees anytime soon..or try to "commune" with them....lol. I'm much too practical for that !