Using only his iPhone, photographer Mark Hirsch captured the ever-changing world of a bur oak tree in a cornfield. The photos, taken daily for a year, revealed a universe of subtle wonders and a therapeutic adventure of self-discovery, inspiration, and enlightenment. Hirsch posted the evolving photo journal on Facebook, attracting thousands of followers. The images are the subject of the widely loved photo book, That Tree. Visit the gallery and experience That Tree's edifying life lessons.