Read and developeOnline version What can trees tell us about climate change? Quite a lot, actually! But to understand what the trees tell us, we first have to understand the difference between weather and climate. Weather is a specific event—like a rain storm or hot day—that happens over a short period of time. Weather can be tracked within hours or days. Climate is the average weather conditions in a place over a long period of time (30 years or more). Scientists at the National Weather Service have been keeping track of weather in the United States since 1891. But trees can keep a much longer record of Earth’s climate. In fact, trees can live for hundreds—and sometimes even thousands—of years! One way that scientists use trees to learn about past climate is by studying a tree’s rings. If you’ve ever seen a tree stump, you probably noticed that the top of the stump had a series of rings. It looks a bit like a bullseye. These rings can tell us how old the tree is, and what the weather was like during each year of the tree’s life. The light-colored rings represent wood that grew in the spring and early summer, while the dark rings represent wood that grew in the late summer and fall. One light ring plus one dark ring equals one year of the tree’s life. Because trees are sensitive to local climate conditions, such as rain and temperature, they give scientists some information about that area’s local climate in the past. For example, tree rings usually grow wider in warm, wet years and they are thinner in years when it is cold and dry. If the tree has experienced stressful conditions, such as a drought, the tree might hardly grow at all in those years. Scientists can compare modern trees with local measurements of temperature and precipitation from the nearest weather station. However, very old trees can offer clues about what the climate was like long before measurements were recorded. In most places, daily weather records have only been kept for the past 100 to 150 years. So, to learn about the climate hundreds to thousands of years ago, scientists need to use other sources, such as trees, corals, and ice cores (layers of ice drilled out of a glacier). by Mar Narváez 1 1. Select the events that you can relate to the weather Choose one or more answers a Winter b Summer c Droughts d Hurricane 2 What do the tree rings indicate? Choose one or more answers a Climate b The past of their habitat c age d Current state of the weather 3 What climatic conditions can be evidenced in the study of the tree rings? a Rain and Increase in temperature b Humidity and Cold c Fires and floods d All of the above 4 why do scientists need to study trees to learn about the weather of the past? Choose one or more answers a because they reveal secrets about climate change b because they can find information related to precipitation, temperature and other data for a specific year. c to know if there was a sudden change in temperature such as a fire d to know what type is the tree 5 5. Taking into account the reading that you can interpret from the rings of this log a The light-colored rings represent wood that grew in the spring and early summer, while the dark rings represent wood that grew in the late summer and fall. b The light-colored rings represent wood that grew in the spring and early summer c the tree is 48 years old d during the life of the tree there was a fire Feedback 1 great! 2 great! 3 great! 4 great! 5 great!
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