Trees, Healing, and Hope

Then the angel showed me the river of the water of life, bright as crystal, flowing from the throne of God and the Lamb through the middle of the street of the city. On either side of the river is the tree of life with its twelve kinds of fruit, producing its fruit each month; and the leaves of the tree are for the healing of the nations.
-Revelation 22:1-2

Rivers and trees. The Bible begins and ends with rivers and trees: Genesis 1-2 and Revelation 21-22. Why is this striking fact not more well known among followers of Christ? What might this latter text teach us about hope in Advent 2014?