How do I get to Rut'Theran village in the Breaking Waves of Change quest:

The summary of the Night Elf version of this quest is:

Use the teleportation tree in western Darnassus to reach Rut'theran Village, then speak to Vesprystus to secure a ride to Lor'danel.

And the quest text states, in part:

Please, hunter, use the western tree to reach Rut'theran, then speak to Vesprystus to secure a flight to Lor'danel.

If you go west from the bank which is in the center of Darnassus, you run directly into this tree. It has a purple glow at the bottom of it, which you run into. It's also the only tree (or the only much of anything) in the western part of the city.

The Worgen version of this quest doesn't bother to explain how to use the tree, since you would have already used the tree once to enter the city only a few minutes prior to getting this quest, and thus presumably would remember where it is. The quest itself makes reference to this:

You must travel back down to Rut'theran Village, where we first arrived, and speak to Vesprystus to secure a ride to Lor'danel.

In either case, there is now an additional flight master in Darnassus next to that same tree, who will also fly you to Lor'danel, if for some reason you can't find the tree she's standing next to. But flying from here takes extra time compared to taking the tree portal; it flies over Teldrassil, not through the portal.

Above the "T" in Temple Gardens on a map of Darnassus is a tree. Underneath this tree is a purple glowing area. Entering this will cause you to teleport to Rut'Theran village. In Rut'Theran village you'll see a similar tree you can use to teleport back.