Hey all, I've always wanted to help on a project like this and traps are somewhat of a specialty of mine so it you want some help I'd be more than willing. Besides, swamps are one of my favorite environments.

Just off the top of my head....

Crushing Vine Trap

Mechanical; Location Trigger; Manual Reset.

Description: When a wire is tripped a heavy counter weight is dropped pulling taunt a number of vines. These vines pin the target against a nearby tree and crush them should they be unable to escape.

Reflex DC13 Negates

On a failed save the target is considered pinned and will begin taking crushing damage each round it remains trapped. Each round the target takes 1d6+1 damage from the crushing force of the vines. A DC 14 strength check will prevent damage for that round while a DC 18 Strength check or Escape artist check will free the target. Alternatively, someone may make a full round action with a slashing weapon to free the target or to make the Strength check for them.

Search DC 18, Disable device DC 14.

I've no idea for the CR and I will revise it when I'm not rushing out the door.