The Scottish Highlands were once the site of extensive forests, but these forests have mostly disappeared and been replaced by peatbogs.
苏格兰高地曾经是大片森林的所在地,但这些森林大部分已经消失,取而代之的是泥炭沼泽。
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The researchers measured the retreat of the permafrost border byobserving hummocks known as "palsas, " which form naturally over icecontained in the soil of northern peatbogs.
There is probably some double-counting in the two sets of figures, because many peatbogs are found in forests, and are thus drained as those forests are cleared.