Why Do Trees Have Rings? | Earth Science

You can tell how old a tree was by the rings in its trunk, but where do they come from? James May is here to answer. "Subscribe to Earth Science for more fascinating science videos - http://bit.ly/SubscribeToEarthLab All the best Earth Science videos http://bit.ly/EarthLabOriginals Best of BBC Earth videos http://bit.ly/TheBestOfBBCEarthVideos Here at BBC Earth Science we answer all your curious questions about science in the world around you. If there’s a question you have that we haven’t yet answered or an experiment you’d like us to try let us know in the comments on any of our videos and it could be answered by one of our Earth Science experts. "