An analysis of records kept by iconic naturalists Henry David Thoreau and Aldo Leopold has revealed evidence that some native plants in the eastern U.S. are flowering as much as much as a month earlier in spring than they did even just six decades ago. Writing in the journal PLoS ONE, scientists from Boston and Harvard universities and the University of Wisconsin-Madison report that many plant species found in and around Concord, Mass. — including serviceberry and nodding trillium — are now blooming an average of 11 days earlier than when Thoreau kept copious notes in the 1850s. In Wisconsin, where Leopold and his students collected comprehensive data on spring blooms from 1933 to 1945, the evidence of earlier flowering is even more pronounced: During the unusually warm spring of 2012, the study says, plants bloomed an average of one month earlier than they did 67 years earlier. Scientists say the findings could provide critical insights into the effects of climate change on native plants, and the long-term implications this could have on the plants and the animals and insects that depend upon them.