Southwest of Taupo and south of Rangipo in the Kaimanawa Forest Park, the 17km Tree Trunk Gorge track (aka Kaimanawa Road) is an awesome bush singletrack. The route passes through some loamy, dense forest.
To reach the mountain biking trailhead from Turangi, head south on SH1 for 10.3km to Rangipo. Continue south on SH1 past SH46 for 11.8km to Tree Trunk Gorge Road. Turn left heading east on Tree Trunk Gorge Road for 5.2km across the gorge bridge. The signed trailhead starts on the left. There is roadside parking for a few vehicles.
Overall, Tree Trunk Gorge Track is the 6th most popular mountain bike trail of all 41 mountain biking rides in New Zealand.