"As climate changes, garden zone map does too"
Found this in the Environment/Energy Group, from DUer bloom:
As climate changes, garden zone map does too
James Willhite
Columbia News Service
May. 18, 2006 12:00 AM
NEW YORK -- With their yellow flowers marooned in the February ice, the daffodils of Manhattan's Morningside Park looked out of sync with their frosty surroundings. But as peculiar as it was to see flowers poking through snow, they were only doing what they always do: responding to warmer soil by springing to life.
In early February, the National Oceanic and Atmospheric Administration announced that the average U.S. temperature for January had been the highest ever. And the daffodils weren't the only ones to notice. In March, The New York Times reported that because of the warm January the maple trees in New York state that produce syrup began growing too early, which could slash this year's syrup output by 40 percent.
Against the backdrop of these shifts, the U.S. Department of Agriculture is now in the process of redrawing the USDA Plant Hardiness Zone Map, a tool used by gardeners to determine what trees, flowers and food crops will survive in what zone. The map, created in 1960 by Henry T. Skinner (then director of the U.S. National Arboretum in Washington) codes the country into 11 regions, determined by the duration of cold weather and lowest winter temperatures in each zone...
And so, as gardeners across the country wait for the newest official USDA zone map, the National Arbor Day Foundation has published its own revised version, based on the same data used by the abandoned AHS map--data that shows in some parts of the Northeast an increase of as much as 8 degrees in winter temperatures."
http://www.azcentral.com/home/garden/articles/0518garde...check out "See a comparison of changes between 1990 and 2004.):
http://www.arborday.org/media/zones.cfm