For this reason, a windbreak works best if it contains only sixty to eighty percent of the trees and plants that would be needed to make a solid line.

出于这个原因，如果防风林只包含60%到80%的可以组成一道坚固防线的树木或植物，它所起到的效果最好。

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Big and tall trees must be chosen to establish windbreak forests.

防风林一定要选用高大的树木品种。

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