Climate change affects Thoreau's woods
Henry David Thoreau spent so much of his career working on his book Walden, which was his thoughts on his natural surroundings - in this case a pond in Massachusetts. He started his experiment in Simple Living on July 4, 1845, when he moved to Walden Pond. He uses the passage of the seasons to symbolize human development, but he also documented the plant and animal life there so closely that it is still useful today.
Indeed, it has proved useful employment for modern climate researchers. From 1852 to 1858, Thoreau kept meticulous records of the plants that bloomed in the Concord, Mass., woods near Walden Pond. Researchers who recently repeated those measurements have compared the findings, old and new, revealing the signature of climate change in Thoreau's woods.
Richard Primack and graduate student Abraham Miller-Rushing of Boston University surveyed the plants in woods near Concord from 2003 to 2007, recording the abundance of various species and what day they flowered each season. They combined these results with data collected by Thoreau in the 1850s and another naturalist in the late 1800s.
They found that 27 percent of Thoreau's species have disappeared from the area and another 36 percent are so rare now that they will most likely disappear soon. The temperature of the area has also risen by 4.3 degrees Fahrenheit in the last 100 years.
Results have shown that the plants in this area are reacting in different ways to the change and that not all plants are affected in the same way.
Thoreau provides part of the allure of studying the woods in Concord, but the location also happens to be a good test site because about 60 percent of natural areas there remain undeveloped and 35 percent of the landscape is protected, reducing the effect of habitat loss or urban development on the plants. This points the finger to climate change, Davis said.
It is not yet known why some flowers can adjust their flowering times and others can't, or why changing the time of flowering improves survival. It seems that Thoreau could still teach us a lot about climate change today.