TUSTIN — As the initiated can attest, the passage of time feels different at ground level than it does perched in a tree. Harv Teitelbaum calls it “tree time.” “You’re in a different world and a different time,” said Teitelbaum, who is a longtime member of the Global Organization of Tree Climbers, which is holding its annual International Recreational Tree Climbers Rendezvous later this month in Osceola County.

Teitelbaum has been climbing trees for 25 years, starting shortly after the Sept. 11, 2001 World Trade Center terrorist attacks — an event that sparked him to seek out more meaningful pursuits in his life. “I wanted to get out and do something that was more in touch with who I was .

.. we shouldn’t be wasting our lives for things that don’t mean a lot,” said Teitelbaum, who first witnessed tree climbing as a recreational activity on television; it looked so compelling to Teitelbaum that he immediately tracked down the climber he saw on TV and began training with him in Georgia.

In 2007, Teitelbaum and a handful of other climbers started the non-profit tree-climbers organization. Teitelbaum served as the club’s first president. While the annual gathering of tree climbers is something that has been happening since 1999, Teitelbaum said the techniques of tree climbing first were developed decades before, in the mid-1980s.

Like other popular climbing activities such as rock climbing or wall climbing, tree climbing has its own set of best-practices to.