I remember from a Learning Channel discussion or something of that nature,
where certain species of trees will "communicate" via pheramones to one
another if a member is under insect attack. IE, a tree becomes infested
with gypsy moths (sake of argument), so it responds by producing a toxic
It also releases a pheremone that other trees of the same species recognize,
so they start producing the chemicals in advance to ward off infestation.
I'm interested in the species of trees that do this, and also some links
about it as well.