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 73 oak, 2400 m Costa Rica DHJanzen101206.jpg high resolution
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| At the same elevation as the glacier face in image DHJanzen101203.jpg above, but at ten degrees north latitude (in the mountains of central Costa Rica), the vegetation is quite another matter. This oak (Quercus copaiensis, Fagaceae), separated from what was a continuous forest canopy 35 m tall by a recent logging operation, is several hundred years old and has far more resources than does the plant in image DHJanzen101205.jpg above. Call up the two images side by side and contemplate why and how they differ. Where this giant oak stood, a glacier scoured during the last Pleistocene glaciation of North America - but while it did it, this oak lived down near sea level only a few kilometers away. When the glaciers retreated away to nothing, this oak marched right back up the hill. | ||
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