Trees: you can climb them, pick fruit off them, chop them down for wood, or just gaze at them admiringly. And they serve just as many symbolic purposes, too.
Paul D thinks that "trees [are] inviting; things you could trust and be near; talk to if you wanted to as he frequently did since way back when he took the midday meal in the fields of Sweet Home" (2.4). Sure they are—for him. Trees, to Paul D, become signs of a second life, a second chancel like when the Cherokee direct him to follow the blossoming trees all the way up to Cincinnati and 124 (10.31-34).
For Denver, trees—or more specifically, bushes—signal a safe place, like her "five boxwood bushes, planted in a ring" (3.1), a place where "Denver's imagination produced its own hunger and its own food, which she badly needed because loneliness wore her out" (3.3).
Sounding pretty good, right? Not so fast. Trees have a totally different meaning for Sethe, whose back Amy Denver calls a "chokecherry tree" (1.153). Her "tree" is more a sign of the past—and not a very pleasant one. Actual trees also bring up some pretty dark thoughts for her, like the whole dead-man—Oh! Is that Paul A?—hanging-from-a-tree thing (19.217).