Can trees "communicate?"

[bhb]

I had one of those smile and nod conversations the other day. The person I was conversing with was explaining to me how trees can “talk to each other” and that modern science couldn’t explain it. There was one point in his conversation which I had heard in the past, the assertion was that when a tree is infected it sends out some sort of a distress signal and nearby trees try to build up their immunity to it. Is there any validity to his claims and specifically to the one I mentioned?

[Q.E.D]

Chemical communication is not confined to the animal kingdom since plants do some pretty strange things too. Watson describes how the acacia tree responds to browsing, or being beaten with a stick, by increasing the levels of tannin in its leaves within minutes. Remarkably, the tannin levels then rise in neighbouring trees, and, due to its bitter taste, repel the browsers before they can do any further damage. This example of plant communication is not restricted to acacia trees, and has been demonstrated in other plants as well as between plants and animals.

From here. So, some plants can communicate chemically, but I wouldn’t go so far as to call it “talking”.