date: Mon, 11 Feb 2002 15:20:17 +0000 from: Juliette Shackleton subject: Tree rings Mark 2 to: k.briffa@uea.ac.uk Keith Just in case you've not had a look at the piece I sent through late last week, here's a second version (after it has been improved by our editor). I've attached it and also pasted it in below - in case you've got any problems opening the attachment. Many thanks Juliette S Chapter 3: Before records began: Tree rings Page 1 What can chunks of old wood tell scientists about historical climate change? If you've ever seen a tree stump you'll have noticed the growth rings - new wood added around the trunk each year in the growing season. Each tree's rings provide a year-by-year climate record, because their thickness is affected by the weather. Dendrochronolosit Keith Briffa tells antenna more. Page 2 'Rather than cutting down trees, we work by drilling a small core through the tree. It doesn't harm the tree and we get the record.' But translating what the rings tell scientists about the climate isn't easy - because climate isn't the only thing that can affect how thick the annual rings grow. 'It isn't just about sunshine and rainfall. It's also things like how fertile the soil is, how old the tree is, and whether there has been any insect attack. We have to separate all these things out to see what the climate signal is.' Page 3 To work out which years the rings in any one core belong to, Dr Briffa has to compare and align rings from one tree to those of another tree of similar age from the forest, looking for certain rings that he knows represent years of fast growth. By doing this, scientist build libraries of tree records based on average growth widths for each area. In some cases, they can even match trees up from overlapping historical periods to get a very long record. Page 4 'We have used fossilised trees from peat bogs to get a timeline that goes back thousands of years, even though individual trees that make up the record only lived for a few hundred years. ' 'Using tree rings, we can take a serious look at natural changes in the climate, before man had much influence. They are the only detailed records we have before records began. ' Page 5 'The tree rings really back up the climate change message - that what we're seeing this century is really unusual warming. We've seen nothing like it in the past thousand years and more.' Keith Briffa, Climatic Research Unit, UEA Other natural indicators including corals, stalactites and ice cores also show year-by-year changes in climate - put together, they point at today's climate changes being quicker than ever before. ******************************************************************** This e-mail and attachments are intended for the named addressee only and are confidential. If you have received this e-mail in error please notify the sender immediately, delete the message from your computer system and destroy any copies. Any views expressed in this message are those of the individual sender and may not reflect the views of the National Museum of Science & Industry. The NMSI website can be found at http://www.nmsi.ac.uk ********************************************************************* Attachment Converted: "c:\eudora\attach\Keith Briffa Mark2.doc" Dr Juliette Shackleton Wellcome Wing Project National Museum of Science and Industry Science Museum Exhibition Road South Kensington London, SW7 2DD. Tel: 0207942 4819 Fax: 0207 942 4241 http://www.sciencemuseum.org.uk/wellcome-wing/ ***** Science Museum - Voted London Visitor Attraction of the Year 2001*****