Can trees talk? Yes, but not in words. Scientists have reasons to believe that trees do communicate with each other. Not long ago, researchers learned some surprising things. Some caterpillars(毛毛虫) attacked a willow tree(柳树) in the woods. The tree changed the chemistry of its leaves and the leaves tasted so terrible that the caterpillars stopped eating them. Then even more surprising, the tree sent out a special vapour (蒸气) a signal causing its neighbours to change the chemistry of their own leaves and make them less tasty.

    Communication, of course, doesn't need to be always in words. We can talk to each other by smiling, raising our shoulders and moving our hands. We know that birds and other animals use a whole vocabulary of songs, sounds and movements. Bees dance their signals, flying in certain patterns that tell other bees where to find nectar(花蜜) for honey. So why shouldn't trees have ways of sending messages?