Climate Central: The spring of 2012 was the earliest recorded across the U.S. since 1900. In many states, signs of spring arrived almost three to four weeks earlier than expected. Unseasonable warmth prompted unusually early blooms, particularly on fruiting trees in the Northeast and Great Lakes regions. Observers in Massachusetts and Wisconsin reported that flowering came earlier than it had since Henry David Thoreau took note of when plants began to bloom near Walden Pond in the 1850s or since Aldo Leopold observed...