Kolima Forest

Kolima Forest is a dungeon area that occurs after the party passes Bilibin. It is more usually beaten before going to Imil, but it is quite possible to beat Mercury Lighthouse and recruit Mia beforehand. Kolima Forest features some log-rolling puzzles, and when you beat it, it turns out to be only a lead-up to the dungeon inside Tret.

Walkthrough
Begin by taking the rightmost path and pushing the log into the water. It will float, making an extra platform that can be stood on. Head north, and then push one more log to take the exit on the left into a new map.

First, walk over to the tree (by pushing the log in front of you out of the way) and use Catch to grab the nut off of it. Push the log back to its original position and head down the path that it was blocking. Go to the left side of the map and you will see two logs at 90 degree angles to each other, separated by one character-width. Push the horizontal log down, and then pass through the path opened up to move past the vertical log without rolling it. Follow this path until it leads to an exit at the north.

This is where things start to get complicated. Head along a path to the right side (it's partially obscured by trees) until you are standing near the only vertical log. Push it to the left. Go up the northern path that was just opened until you are standing north of the horizontal log that the previous one just ran into. Push it south, then push the vertical log back to its original position. Now, head along the section that the vertical log was formerly blocking to push the second horizontal log down (it should only move 1 character width.) Now, push the first horizontal log to the north; this will clear the way so that you can push the vertical log into the water. Jump across the water by standing on the now-submerged vertical log, and follow the path up the stairs and back to the right. This will lead to another map.

On this map, several horizontal logs are floating in a pool of water, creating a bridge across; the only problem is that currently, they don't lead anywhere at all, but instead point to a stump on the opposite shore that you can't jump to. At the south edge of this map is a gate with a sign that reads, "Floodgate switch - Do not touch!" Well, to advance you're going to have to break this rule. Let all the water out, and you'll be able to roll the logs. There's also an item on the opposite shore; to reach it, you'll have to create a different path than you would to get across the water.

To get the item, roll both horizontal logs to the north, then move both of the vertical logs as far right as possible. Go up, and roll the rightmost horizontal log down so that it runs into it. Now, push the southernmost vertical log to the left, then push the leftmost horizontal log down so that it is even with the rightmost one. Close the floodgate and jump across. The item is the Fur Coat, a water-resistant equip. Once you have it, you can reset the logs by exiting the map and coming back in. Then follow the normal directions below.

To pass through, lower the floodgate switch. Roll the northernmost vertical log over one spot, then carefully exit, so as not to disturb the other logs. refill the water and jump across. In the next map, you will see Laurel, a giant tree that was seen talking to Tret in Kolima's cutscene. You can talk to him, but he doesn't have much to say. Walk to the right and you will see Tret. Again, you can talk but he has little of importance. Climb the vine next to him to begin the second portion of the maze.

After completing the second portion, you will be required to use an item called Hermes' Water on Tret outside, an item which is only found after completing Mercury Lighthouse in a separate event. If you happened to complete that dungeon before this, then you can use the water on Tret's face on the tree right away. If not (which would be typical), you would leave the forest and come back much later.

Once Hermes' Water is in your inventory, return to Kolima Forest and navigate the forest once more, and return to Tret and use the item. He will become restored, and then return everyone who is a tree back to their human state. You discover in doing so that it was the Psynergy stones blown out of Mt. Aleph during its' eruption that gave him the power to turn people into trees. When the people of Bilibin came to Kolima for materials for Lady McCoy's house, they incited his rage and everyone in range became a tree. Monsters no longer appear in Kolima Forest once this is completed, and the residents of Kolima are back to normal. You should pay them a visit.

Items
Nut - Dangling on a tree in the middle of the second area. Use Catch to grab it.

Fur Coat - At the end of the water-and-dam puzzle.

Story
When Lord McCoy of Bilibin's wife wishes for a new manor to be built for her use, the Lord commissions the lumberjacks of Kolima to harvest wood for the building. This goes so far as to even threaten the "holy" tree at the centre of the forest, Tret. These actions cause the tree to feel agony and sadness, as well as overriding rage, in much the same way a parent would when their children are in danger. It is at this time that Mt. Aleph erupts, raining Psynergy Stones across Weyard. Many of these fragments fall upon Tret's foliage, turning his rage into a monstrous entity, which consumes and possess him. This newfound rage is exacerbated as the Psynergy Stones give Tret the ability to utilise Psynergy, making him a dangerous force to anyone within his range of power. Unfortunately for the citizens of Kolima, this includes them, and Tret turns the entire populous stationed there into trees. Mortally wounded by the previous timber-collecting, Tret begins to die, and as he does, so does the entire forest, which now include the residents of Kolima. Fortunately for them, Isaac's party was forced to take this route south as the only other route to Venus Lighthouse, the bridge to Kalay, was severed by the same eruption that triggered Tret's mutation. As the party travels into this forest, they discover that as Adepts they are able to withstand the curse and defeat Tret's rage, though by this stage he is too weak to undo his spell, seemingly dooming the Kolima Forest. However, due to Saturos' party's actions at Mercury Lighthouse, the Water of Hermes once again began to fill the fountain at the Lighthouse's base. This water's miraculous healing properties gives Isaac's party the ability to revive Tret, ending his curse and restoring tranquillity to the area.