CLINTON, Md., Nov. 13 (UPI) -- Regions across the Southern United States are seeing leaves appear later in spring, possibly because of the warmer climate, a researcher said.
Expressing surprise, Xiaoyang Zhang of Earth Resources Technology in Camp Springs, Md., said, "Nobody had noticed how warming temperatures can delay the green-up."
Zhang spotted the irregularity when he examined satellite images of seasonal changes in vegetation color across the United States from 1982 to 2005, New Scientist reported Tuesday. In areas of northern latitudes, plants came into bloom an average of 0.32 days per year earlier during the study period. But in other places, plants bloomed an average 0.15 days later.
Zhang said he thought some plants need exposure to a short cold snap to sprout. Plants at northern latitudes still get this, but those in more southerly latitudes don't, causing them to sprout later.
