美国加利福尼亚大盆地国家公园的刚针松林
刚针松林如图:http://earthobservatory.nasa.gov/Newsroom/NewImages/Images/schulman_iko_2003145_lrg.jpg
The bristlecone pines of California’s White Mountains are some of Earth’s oldest living things. The ancient trees—at least one over 4,700 years old—live in an otherwise barren environment. Cold and dry conditions limit the growth of bristlecones, and annual variations in temperature and precipitation are recorded in their growth rings. These rings form a record of past climate conditions. Scientists use the rings to reconstruct the climate history of the area. Bristlecone pine tree-ring records, derived from living and dead wood, extend back roughly 8,900 years.
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