ἐν μέσῳ τῆς πλατείας αὐτῆς· καὶ τοῦ ποταμοῦ ἐντεῦθεν καὶ ἐκεῖθεν ξύλον ζωῆς ποιοῦν καρποὺς δώδεκα, κατὰ μῆνα ἕκαστον ἀποδιδοῦν τὸν καρπὸν αὐτοῦ, καὶ τὰ φύλλα τοῦ ξύλου εἰς θεραπείαν τῶν ἐθνῶν (Revelation 22:2, WH).
BDAG seems to indicate that XULON in Rev. 22:2b refers to trees by the water. Conversely, Tyndale renders the passage:
"and on either side of the river was there wood of life . . . and the leaves of the wood served to heal the people withal."
On the other hand, commentator David Aune suggests:
"On each side of the river there were trees of life" and he makes these comments:
"The term XULON, 'tree,' is a collective referring to numerous trees found along banks of the river" (Revelation, 52C:1177).
Examples of XULON being used collectively are found in Gen. 1:11-12; 3:8; Lev. 26:20; 1 Chron. 16:32; 2 Chron. 7:13; Eccl. 2:5; Jer. 17:2.