You can heal yourself using sunlight.
Benefit: You can temporarily draw energy from the sun to heal your wounds. Once per day while you are using change shape to assume a plant form, you can activate this ability as a free action to gain fast healing 1 for a number of rounds equal to your Hit Dice, as long as you are in an area of bright, natural sunlight.
When you rest in plant form in bright, natural sunlight, you are healed of twice the normal amount of hit point damage and ability score damage.
Pathfinder Roleplaying Game Ultimate Wilderness © 2017, Paizo Inc.; Authors: Alexander Augunas, John Bennett, Robert Brookes, John Compton, Dan Dillon, Steven T. Helt, Thurston Hillman, Eric Hindley, Mikko Kallio, Jason Keeley, Isabelle Lee, Jason Nelson, Stephen Radney-MacFarland, Alex Riggs, David N. Ross, David Schwartz, Mark Seifter, Jeffery Swank, and Linda Zayas-Palmer.