Then he stepped onto the leaves of the fallen tree, and began singing.

然后，他踩在倒下的树的叶子上，开始唱歌。

youdao

The road was partially blocked by a fallen tree.

倒下的一棵树挡住了部分道路。

《牛津词典》

We backfill, kick some leaves around, drag over a small fallen tree.

然后我们把土填回坑里，踢过来一些树叶在上面，又拖过来一棵小枯树。

youdao

With the furs on his back, and his gun in his arms, he stepped out on the fallen tree.

VOA: special.2010.06.26

If you ever tried to walk on a fallen tree log, you understand what the expression means.

VOA: special.2009.06.07

"It gives drivers sufficient time to react if there is, for example, a fallen tree on the line, " she said.

BBC: NEWS | UK | England | Power supplies cut by high winds

Rachel McDonald, the pub's owner, said there was "lots of mud everywhere" and said the river had been blocked by a fallen tree trunk.

BBC: Homes in Somerset are flooded as river bursts

One used mushrooms on mossy bark harvested from a fallen tree.

WSJ: Greenery, With Hints of the Forest and Desert