《瓦尔登湖·第九章·湖·The Ponds》第7节
This rise and fall of Walden at long intervals serves this use at least; the water standing at this great height for a year or more, though it makes it difficult to walk round it, kills the shrubs and trees which have sprung up about its edge since the last rise, pitch-pines, birches, alders, aspens, and others, and, falling again, leaves an unobstructed shore; for, unlike many ponds and all waters which are subject to a daily tide, its shore is cleanest when the water is lowest. On the side of the pond next my house, a row of pitch pines fifteen feet high has been killed and tipped over as if by a lever, and thus a stop put to their encroachments; and their size indicates how many years have elapsed since the last rise to this height. By this fluctuation the pond asserts its title to a shore, and thus the shore is shorn, and the trees cannot hold it by right of possession. These are the lips of the lake on which no beard grows. It licks its chaps from time to time. When the water is at its height, the alders, willows, and maples send forth a mass of fibrous red roots several feet long from all sides of their stems in the water, and to the height of three or four feet from the ground, in the effort to maintain themselves; and I have known the high-blueberry bushes about the shore, which commonly produce no fruit, bear an abundant crop under these circumstances.
注释摘要
梭罗在这段文字里写出了瓦尔登湖一个极富个性的生态节奏：湖水以数年乃至十几年的长周期涨落，而不是随季节性的干湿简单变化。当湖水保持在高位一年甚至更久，它会淹死自上一次退水之后在岸边扎根的灌木与乔木——他点出了脂松、桦树、赤杨、山杨等新英格兰常见树种——等水位退去，就露出了一条干净的、没有植物侵占的湖岸线。这恰好与受每日潮汐影响的水体形成对照：潮汐水域在退潮时…