牠们有又重又直的树干。
温带林地火灾火焰干烈、蔓延迅速，有时会一直沿着树干烧至树冠。
Temperate-forest fires burn hot and fast, and sometimes all the way up to the crown of a tree.
游客们一直摘树叶，并把他们的名字刻在树干上。
Thee tourists have been picking the leaves and cutting their names on the tree-trunk.
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