Tree climbing is a recreational or functional activity consisting of ascending and moving around in the crown of trees.
A rope, helmet, and harness can be used to ensure the safety of the climber. Other equipment can also be used depending on the experience and skill of the tree climber. Some tree climbers take special hammocks called "Treeboats" and Portaledges with them into the tree canopies where they can enjoy a picnic or nap, or spend the night.
Some tree-climbers employ a mixture of techniques and gear derived from rock climbing and caving. These techniques are also used to climb trees for other purposes: tree care (arborists), animal rescue, research, and activism.
Children commonly climb trees for play without the use of equipment.
Tree climbing as an organized recreational activity using modern climbing equipment emerged in the early 1980s in USA. In 1983, Peter "Treeman" Jenkins, an active arborist and retired rock climber, founded Tree Climbers International, Inc. TCI eventually developed written safety and training rules for tree climbing which are used to this day. Now there are numerous organizations promoting tree climbing around the world (Japan, USA, France, UK, Canada, Taiwan, Australia, Malaysia, Indonesia, China etc.).
In 2007, a meeting of experienced tree climbing facilitators and instructors, including Peter Jenkins, and organized by Harv Teitelbaum of Tree Climbing Colorado and Abe Winters of Tree Climbing USA, took place in Colorado, USA to discuss the formation of the first democratic umbrella organization dedicated to serving the recreational, adventure, experiential and educational tree climbing communities. From those initial meetings, GOTC (Global Organization of Tree Climbers) was formed and incorporated as a charitable, nonprofit organization. Today, GOTC provides training curricula and safe climb guidelines in use worldwide and adopted by experiential organizations including the AEE (Association for Experiential Education).
Climbing a tree every day for a year, (a 365 project), or for longer, has become a challenge taken up by several artists, Todd Smith from Louisville, KY, USA, climbed a tree every day for 3 years. Henrik G Dahle, invited people to climb with him and interviewed people in the canopy of trees, including former 365 tree climber Leo Murray of Monkeydo, who now facilitates tree top adventures. Other artists include Christopher B Gray from Connecticut, USA, Kamila Wajda from Przybowka, Poland and Cecylia Malik from Kraków, Poland who has published a book on her year climbing trees.
Many different techniques (free climbing, self-belayed climbing with a doubled-rope technique, single-rope technique, and lead climbing) are used to climb trees depending on the climber's individual style, purpose, and preferences. Of course free tree climbing has been practiced throughout the history of the human race, and is much more common than using any kind of technological aid.
Technologically-aided tree climbing is performed by lapping a long rope over a limb and ascending the fallen end using a friction knot tied from initial tie's excess "tail." The difficulty of any particular climb depends on many factors: the regularity of branching, the brittleness of dead wood in some species, whether the bark is rough or smooth, the width of the trunk and branches, the height of the tree, the location of the tree, and the weather are all factors.
The first obstacle is getting into the tree, which may employ techniques of aid climbing such as ascending a fixed rope, ladder or etrier, or else free climbing up limbs or other structures into the tree, but generally the throwline technique which is used. This is done remotely from the ground utilizing a throw weight and line. The throw weight is a small canvas sack filled with shot and adorned with a ring on one end for attaching a lightweight pilot line. The weight is swung from its attached line as a pendulum, with the line either held between two fingers of one hand at hip level, or in a basket configuration achieved by running a bight of the line back through the ring that is held in the other hand, with the weight being swung between the legs in a wide stance. It is then launched toward the targeted branch. Once over the branch, the weight must return to the ground, and may have to be manipulated so as to isolate a single anchor point (doubled rope technique), or for SRT into an optimal redirect. The throw bag is then removed; the climbing line is tied on, and pulled through the canopy and back down again, at which point the climbing system may be installed.
The doubled-rope technique (DRT or DdRT) is used to self belay the climber in such a way that the rope can be retrieved without going back up the tree. One end of the rope is fastened to the climber's saddle (harness), from there the rope passes around the tree and back to a friction hitch, which is also attached to the climber. This system allows the climber to easily adjust the rope to provide a belay if free-climbing, or to go up or down if hanging on the rope. As long as the climber is below the anchor and there is minimal slack in the system, any fall will be restrained. This system can be placed into the tree from the ground, or the climber can advance the rope up the tree over the course of the climb.
The single-rope technique (SRT) is used mainly for getting to the top of large trees that cannot be easily free-climbed. With the adequate hardware, a throw line, an attached weight, and a launching system (e.g., a bow or slingshot), a climbing rope can be anchored to a branch very high in the tree. This is done by launching the weight (with the throw line attached) over the desired limb and tying the climbing rope to the unweighted end. The climbing rope is then hauled over the branch by pulling on the throw line. The line is anchored to the trunk or to the high limb itself by running one end through a closed bight made in the other end. The climber then ascends the rope using a set of friction hitches or mechanical ascenders) to obtain the desired limb. With practice, this method is typically fastest and requires the least amount of hardware. One drawback is that it does not necessarily involve directly ascending the tree itself, as the vast majority of the time spent climbing is ascending the rope, and not the tree itself. Additionally, it can provide greater safety to a climber over DRT or lead climbing techniques, as the climber can rig the rope over multiple limbs when using a ground-level trunk anchor. In the event that one limb breaks, the lower limbs may stop the fall.
Lead climbing is employed by climber where points of protection are formed by girthing the tree's limbs with slings. Once the lead climber ascends the tree, he or she may create a belay or top rope anchor or else simply rappel down. In the event that an anchor is created, other climbers can subsequently climb the tree on belay without having to lead. Drawbacks to this method include the probability of hitting a lower limb or the main trunk in the event of a fall.