The Tsitsikamma Big Tree is a giant Outeniqua yellowwood reached by a short boardwalk through indigenous forest just off the N2. The tree itself is impressive, but the better reason to stop is the forest around it: damp, green, and full of the filtered light that makes this part of the Garden Route feel older than the road running beside it.
The same permit area gives access to the Plaatbos and Goesa forest walks, so it can be more than a quick photo stop if you have time.