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Sweden's Tree Line Moving At Fastest Rate For 7,000 Years
Stockholm (AFP) Jan 16, 2007 Climate change over the past two decades has caused Sweden's tree line to move north at a faster rate than at any time in the past 7,000 years, Swedish researchers said on Tuesday. "The tree line has moved by up to 200 metres (656 feet) in some places. Trees have not grown at such high levels for around 7,000 years," Leif Kullman, a professor at Umeaa University's department of ecology and environmental science, told AFP. The tree line represents a limit in mountainous, northern and southern latitudes beyond which trees do not grow. "Recordings began in 1915 but the trend has intensified in the past 15 to 20 years," Kullman said. Sweden's climate in the past 20 years was as mild as it had been some 7,000 years ago, he added. While some of the change could be explained by natural phenomena such as the reduction in global volcanic activity -- allowing more sunlight to warm the Earth -- the trend was clearly provoked for the most part by man-made factors. "We can say that 75 percent of the change is due to the emergence of greenhouse gases," Kullman said. As the climate has become milder other plants and animals have ventured further north from their traditional habitat. "The number of plants and animals in Swedish forests has grown 100 percent in the last 50 years," Kullman said.
Source: Agence France-Presse Related Links Umeaa University Save the Forests at Wood Pile 
Soil Nutrients Shape Tropical Forests, Large-Scale Study Indicates
Champaign IL (SPX) Jan 12, 2007Tropical forests are among the most diverse plant communities on earth, and scientists have labored for decades to identify the ecological and evolutionary processes that created and maintain them. A key question is whether all tree species are equivalent in their use of resources - water, light and nutrients - or whether each species has its own niche. |
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