《易传·象传下·升》
《升卦》的卦象是巽下坤上，而巽又象征高大树木，这样就成为地里边生长树木之表象。
地中生木，升；君子以顺德，积小以高大。
The hexagram image of Sheng Gua is Xun below and Kun above, and Xun also symbolizes a tall tree, so it becomes a representation of trees growing in the ground.