By Earthscope Reporter, Jillian Johns
Trees can live for centuries, learning along the way. Much as humans become older and wiser, trees do too. However, increasing global temperatures and climate change are causing more frequent fires and droughts which in turn cause long-lived trees to die due to lack of water.
We can learn from trees because they are full of scientific evidence on the climate as recorded during the many years a single tree may have been alive. These pieces of evidence allow for scientists to discover climate information up to thousands of years longer than the technology we have now. These technologies have only been around for about 75 years, giving us only a glimpse of how the climate has changed, but not a fuller image, as the trees give. The area of scientific research titled dendrochronology is just this: the study of trees and their tree rings in order to find how the moisture levels in soils based on recent precipitation and temperatures (also known as PDSI - Palmer Drought Severity Index) has been changing throughout the years.
Daniel Griffin, a dendrochronologist teaching at the University of Minnesota, conducted the Blue Oak Study* in which he and his colleague extracted data from the blue oak trees’ rings to discover how the climate has changed over the past 1,200 years.
By studying the tree rings inside the trunks of trees, Griffin was able to find that we are currently in a state of drought that is the worst in these last 1,200 years. As each ring represents one year of tree growth, the width of the ring tells us how much water the tree had access to during that time. If the ring is thinner, for example, that year must have been much drier. Rings over the past few years, especially in 2012, have been particularly thin compared to rings throughout the preceding years.
This new data will help us to understand the range and severity of the drought as well as what the future has in store. As Griffin said, “The tree ring data can be an important and powerful catalyst for reshaping popular conception about drought and about water in California,” and that information is key to the sustainability of our future generations.
This is a very important study that shows us that we should not take the drought for granted. About 1,200 years ago, the indigenous tribe of Mayans in Central America had a mass die off. Based on recent studies, many scientists believe that this was due to a severe drought. While I am sure we will not face the same end, we do need to be very careful about our decisions on how we manage and care for our water resources at this time.
This new data will help us to understand the range and severity of the drought as well as what the future has in store. As Griffin said, “The tree ring data can be an important and powerful catalyst for reshaping popular conception about drought and about water in California,” and that information is key to the sustainability of our future generations.
This is a very important study that shows us that we should not take the drought for granted. About 1,200 years ago, the indigenous tribe of Mayans in Central America had a mass die off. Based on recent studies, many scientists believe that this was due to a severe drought. While I am sure we will not face the same end, we do need to be very careful about our decisions on how we manage and care for our water resources at this time.
http://www.pbs.org/time-team/experience-archaeology/dendrochronology/
By examining the tree ring width and constructing a timeline using these rings, dendrochronologists are able to find years in which the area with the studied trees may have been in a drought.
* To learn more about Griffin's study, go to http://www.reportingclimatescience.com/news-stories/article/study-californias-drought-worst-in-1200-years.html
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