In order to properly take advantage of this, you must first have Cyrus and his support skill "Evasive Maneuvers" as well as Tressa with her starting ability to gather Leaves after leaving an area/zone. Head over to North Rippletide Coast situated southeast of Atlasdam city and northwest of Rippletide city. On the far right end side of the zone is a dungeon/cave called Undertow Cove which is a level 45 dungeon. Upon entering, there is a small loop/roundabout that you can walk just south of the entrance that brings you back to the entrance and out before being engaged with a random encounter. With Tressa's ability to snag Leaves after she exits the dungeon, you should net between 1,140-1,368 Leaves. Each run takes approximately 10-12 seconds walking or 7-8 seconds running. This nets approx. 6,840 Leaves every ten seconds. and if you're patient, up to approx. 410,000 Leaves an hour (Or for however long you plan to earn).