Forest Terrain

Most forests are filled with trees, or something akin to trees, which provide partial cover to those standing in the same square as a tree. An average tree has an AC of 4, a hardness of 5, and 150 HP (see page 409 for rules on smashing an object). A successful DC 15 Athletics check is enough to climb most trees.

Fungal blooms, vines, roots, and short bushes cover much of the ground in a forest. Undergrowth counts as difficult terrain (see page 257), provides concealment (20% miss chance), and increases the DCs of Acrobatics and Stealth checks by 2. Squares with undergrowth are often clustered together. Undergrowth and trees aren’t mutually exclusive; it’s common for a 5-foot square to have both a tree and undergrowth.

In a sparse forest, the maximum distance at which a creature can succeed at a Perception check to detect the presence of others is 3d6×10 feet. In a medium forest, this distance is 2d8×10 feet, and in a dense forest it is 2d6×10 feet.

Because any square with undergrowth provides concealment, it’s usually easy for a creature to use the Stealth skill to hide. Logs and massive trees provide cover, which also makes hiding possible.

The background noise of a forest makes Perception checks that rely on sound more difficult, usually increasing the DC of the check at the GM’s discretion.