Forests

摘要

@@Since the beginning of agriculture, 12,000 years ago, humans have had an uneasy relationship with forests. On one hand, the forests provided timber, and good hunting for game. But they also took up space where crops might be grown, and provided a refuge for malevolent creatures both real and imaginary. As farming spread out from its first heartlands in the Middle East, northern China and Central America, forests began to lose ground. Already by the time of ancient Greece 2,500 years ago, deforestation was so extensive that Plato lamented that some mountain lands that had yielded good stout timber were now "good only for bees". Evidence from pollen preserved in lake beds shows that the majority of Europe and China's natural forest was already cleared by this time. The remaining forest in both these regions continued a slow, halting decline and reached a low point some time in the last few centuries. A more recent burst of forest clearance occurred when European settlers arrived in North America from the 1600s onwards. At first, there were huge tracts of almost unbroken forest in the east, yet by the mid-1800s most of this forest had been cleared and replaced by farmland. For example, southern New England was more than 90% forested when settlers first arrived, but by 1870 there was less than 25% forest cover. In Midwestern areas such as the forested parts of Wisconsin, deforestation started later (in the 1830s) as settlers moved west, and reached a low point around 1900 with only about 10% forest cover. The character of the surviving forests was also very different. Uncut old-growth forest, which Thomas Jefferson had suggested held enough timber to last 500 years, was mostly gone by the mid-1800s and essentially disappeared in the eastern USA by the 1920s. In its place was younger, regrown forest