The birch tree has white bark, and this tough protective outer layer of the tree, this white bark, is waterproof.

桦树有白色的树皮，树上这个坚硬的保护外层，这个白色的树皮，是防水的。

youdao

I'd like to go climbing a birch tree, and climb black branches along a snow-white trunk toward heaven, till the tree could bear no more.

我想去爬白桦树，沿着雪白的通向天堂的树干，爬上乌黑的树枝，直到树身再支撑不住。

youdao

The white tree,. The birch (also the ash).

白色的树，。桦树(即白杨树)。

youdao

I'd like to go by climbing a birch tree, And climb black branches up a snow-white trunk toward heaven, till the tree could bear no more, But dipped its top and set me down again.

我真想去爬白桦树，沿着雪白的树干，爬上乌黑的树枝，爬向那天心，直到树身再支撑不住，树梢碰着地，把我放下来。

耶鲁公开课 - 现代诗歌课程节选

His senior project involved testing the sugar content of various birch varieties, and he found that white birch New Hampshire's state tree was the sweetest.

WSJ: Birch syrup explored as add-on to maple industry