The transition from forest to treeless tundra on a mountain slope is often a dramatic one.

从森林到山坡上没有树木的苔原的过渡通常会十分突然和明显。

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But the zone is largely treeless, studded with house-size rocky chunks, called hummocks, that broke off the top of the mountain when it exploded.

然而这个区域还是基本上光秃秃的，布满了房子般大小的岩石块，形成一个个的小山岗，这些都是火山喷发的时候从山顶滚落下来的。

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But the zone is largely treeless, studded with house-size rocky chunks, called hummocks, that broke off the top of the mountain when it exploded.

然而这个区域还是基本上光秃秃的，布满了房子般大小的岩石块，形成一个个的小山岗，这些都是火山喷发的时候从山顶滚落下来的。

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