Initial Publication Date: October 13, 2017

Part 1: Exploring Tree-Ring Sites Around the World

Take a look at the sheer number of tree-ring chronologies (green triangles) that have been made publically available by the scientists who originally collected them. Tree-ring scientists contribute their data to the International Tree-Ring Databank (ITRDB) to make the data available to other researchers and to be sure that there is minimal overlap of their research efforts. There are thousands of tree-ring chronologies collected from around the globe, although you can see that most of them come from North America and Europe. Notice that there also places where there is very little data (parts of South America and Africa for example). Sometimes this is because old trees don't grow in these regions, or the trees that do grow there do not produce annual rings making them unsuitable for tree-ring studies. It is also possible that it the logistics of collecting old trees in these regions can be extremely difficult.

Let's explore this tree-ring data a bit more. In this activity, you will focus on tree-ring data from the northern latitudes where trees are sensitive to changes in summer temperature, and you will learn how to find this data in the ITRDB. You will then use online resources to do some background research on the scientific investigators that contributed to ITRDB by searching for peer-reviewed literature about the tree-ring sites that you choose to investigate.


1. Explore the International Tree-Ring Databank (ITRDB)

Right click to open the International Tree-Ring Databank (ITRDB) site in a new window.

2. Scroll to the "Interactive Map" link and click on it.

3. One you are in the Paleoclimatology Data Map, click on the "identify" option in the "Paleo Network Tools" box.

4. Choose three tree-ring sites to explore that are located in different regions of the northern latitudes or boreal regions (look at the map of the boreal forest in Part 1 of this lab if it is helpful. Look in Alaska, northern Canada, Siberia, etc.). When you are in the "identify" tool, you can just click on a tree-ring site (green triangle) that is of interest. Once you click on a site, the metadata for that site will appear on the left hand side in the results tab. Record the name of each site, the investigator's name, and its coordinates (latitude and longitude) in the table provided in your answer sheet.

5. Select one of your three sites for further study. After choosing the site, click on "Access Data" to reveal the details of the science expedition. Record the following information on your answer sheet.

  • Elevation of the site scientists were investigating
  • Data span of tree-ring cores at the site
  • Species of trees cored at the site
  • 6. Researching the literature with Google Scholar

    All scientists and graduate students do a literature review before they start a new research project. Scientists first ask "What has already been done?", and then figure out how to build upon that work (or work to disprove it). In this section, you will do some additional research on what has been published about the sites you chose. Right click to open Google Scholar in a new window. This site is a search engine that students and scientists use to research what has already been published on a topic.

    7. Type in the name of one of the investigators that you identified in the Paleoclimatology Data Map in the Search box. Add the words "tree ring" after the name. One of the first things to note is how many times a publication has been cited in papers published by the scientific community. See the figure below for example. The paper with O. Solomina as a co-author has been cited by other publications 356 times, a measure of the impact a paper has on the scientific community. 356 citations is a lot of citations! You can also click the "related articles" tab, which is a handy feature. If you include the region the data came from in the search box, you can narrow down the number of publications, for example, typing in "O Solomina tree ring Kamchatka" will result in a smaller list of related publications specific to that region.

    8. Click on a few of the article links from your Google Scholar search for each investigator that you identified on the Paleoclimatology Data Map and try to identify related articles. Read several of the abstracts. Write the title of one of the papers that interests you, and describe in a few sentences (in your own words) what the study is about.

    Stop and Think

    1.1 List the name of each site, investigator, and site coordinates (latitude and longitude) that you found from the ITRDB activity above.

    1.2 List the expedition details from question 5 here.

    1.3 Place your abstract summary, or a brief description of the research, here.