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Genetically modified tree 转基因树木 Into the wildwood 进军森林 A GM species may soon be liberated deliberately 一种转基因树木不久或将大量种植，但很审慎 ONCE upon a time, according to folklore, a squirrel could travel through America s chestnutforests from Maine to Florida without ever touching the ground. 民间流传有这样的故事：很久很久以前，松鼠在穿过美国缅因州到福罗里达州的栗树林时，可以一直不触碰地面。 The chestnut population of North America was reckoned then to have been about 4 billiontrees. No longer. 估计北美那时的栗树约有40亿棵。现在却不复存在了。 Axes and chainsaws must take a share of theblame. 必须说，斧头锯子不乏其罪， But the principal culprit is Cryphonectria parasitica, the fungus that causes chestnut blight. 但栗疫病菌才是罪魁祸首，是这种真菌致栗树感染了栗疫病。 In the late 19th century, some infected saplings from Asia brought C. parasitica to NorthAmerica. By 1950 the chestnut was little more than a memory in most parts of the continent. 19世纪后期，一批亚洲来的感染栗疫病菌的树苗把该病菌带到了北美。到了20世纪50年代，北美大陆大部分地区的栗树便全部消失，成为了回忆。 | 
