Like the legendary beasts who race around Johto, so does the Shifting Forest travel through Hoenn, never in the same place long enough to be found and documented, and often dismissed as an unusually persistent and similarly described myth. This forest does not solely get its name from its frequent journeys, to which many other words could equally apply, but also from the large population of wild Shiftry which patrol its edges. Whenever a passing human is spotted, the Shiftry in unison wave their giant, leafy fan-hands, and with such precision that they do not cut a single root, send the forest, dirt and all, flying on the winds to its next location.
Some have speculated that the reason Shiftry so zealously guard their forest from human interlopers is a fear of loggers, while others claim poachers or pokemon trainers to be a far greater concern; surely, few lumberjacks in the age this forest was first recorded could have stood up to Shiftry in battle. A brave few have entered the forest over the centuries; some by descending from flying pokemon, others by abusing quirks of teleportation, or digging, or simple expert stealth.
What they find in it, without fail, is less interesting than the Shiftry themselves. The lumber is brittle, the pokemon primarily Seedot, with a few others no less common thrown in; if a rare and powerful pokemon is truly at its center, it is even better than the forest itself at evading contact. It appears to man at this point that the Shifting Forest is simply a display of power and soltitude, motivated less by the riches of which treasure-seekers dream than the wish of wild pokemon to grow powerful without trainers, to show off their wind-based attacks, and to create their own legend.