Looks like this is from Shōbōgenzō (13th century). It is too difficult for me to explain the Zen philosophy behind this sentence, but if it is simply to be interpreted literally as a Japanese sentence, as you requested, the most faithful English translation would be "In a human tree, a flower is present. In a human flower, a flower is present" or "There are flowers in human trees. There are flowers in human flowers". (Plurality is not indicated, so it can be either "a tree" or "trees".)
There is no explicit "and" in 人樹 and 人華, so the straightforward interpretations of these compounds would be "human tree" and "human flower" (don't ask me what they are). But if the context clearly tells otherwise, "human and tree" and "human and flower" are possible interpretations.
So this is the original text:
This is why various grasses all bear flowers and fruit. All kinds of tree bear flowers and fruit. Goldtrees, silvertrees, coppertrees, irontrees, coraltrees and crystaltrees, et cetera, they all bear flowers and fruit. Earthtrees, watertrees, firetrees, windtrees and skytrees, they all bear flowers and fruit. Humantrees bear flowers. (In turn, such) humanflowers bear (yet another) flower. (Even) dead trees bear flowers.
The text is basically saying all elements in the world are actually like trees, and thus bear fruit and flowers. Here the kanji 樹 is clearly used as a kind of suffix meaning "-tree", as shown above. I know "humantree" and "humanflower" are not common words, but this 人樹 is indeed "humantree" or "tree of human" rather than "human and tree".