Tree climbers. (TCI ®) is a worldwide organization of people who love to climb trees. Climbing and aerial rescue classes for professional arborist and recreational tree climbers. . We do this safely and with utmost care for the trees we climb. Tree Climbers International ®, Inc. Tree Climbers International -- Everything you want to know about tree climbing. TCI is also the world's first school for recreational tree climbers. Information about tree climbing, tree climbing gear, tree climbing training, and more from the world’s first school and organization for recreational tree climbers. Information about tree climbing, tree climbing gear, tree climbing training, and more from the world’s first school and organization for recreational tree climbers. axptl wohh nf eteu it o23qw strz kc0emq aeygeb kb