Our climate's changing, and so are hardiness maps (Maine)

[jpak]

http://bangornews.com/news/t/lifestyle.aspx?articleid=156106&zoneid=14

For eight years during the 1850s, Thoreau observed the phenology of flowering plants growing in the fields and woods around Concord, Mass. He entered detailed observations into monthly charts, recording the first flowering dates of several hundred species. He was fanatic about this project, a trait that prompted his friend Ralph Waldo Emerson to suggest that he had wasted his life away in the woods. "I cannot help counting it a fault in him that he had no ambition," Emerson said. "Instead of engineering for all America, he was the captain of a huckleberry party."

Sixteen years after Thoreau’s death, a Concord shopkeeper, Alfred Hosmer, continued Thoreau’s work. From 1888 to 1902, Hosmer recorded the first flowering dates of more than 700 species. Like his predecessor, he created handwritten tables from his field notes. Hosmer died in 1903.

A century later, Boston University scientists Richard Primack and Abe Miller-Rushing initiated their own study of flowering dates, copies of both Thoreau’s and Hosmer’s records in hand. According to an article in the October 2007 issue of Smithsonian magazine, "Primack and Miller-Rushing compared three years of their results with those of Thoreau and Hosmer, focusing on the 43 plant species with the most complete records. They learned that some common plants, such as the highbush blueberry and a species of sorrel, were flowering at least three weeks earlier than in Thoreau’s time. On average, they found, spring flowers in Concord were blooming a full seven days earlier than in the 1850s — and their statistics clearly showed a close relationship between flowering times and rising winter and spring temperatures."

Like Thoreau and Hosmer, who observed plants in the wild, veteran gardeners have noticed that garden plants are blooming earlier. So have the creators of the National Arbor Day new 2006 arborday.org Hardiness Zone Map. Based on the most recent 15 years’ data available from the National Oceanic and Atmospheric Administration, this new map shows that many areas of the U.S. have become warmer since the 1990 USDA Hardiness Zone Map was published.

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