Rachel Sullivan swings through a canopy-level obstacle course in the Ourimbah State Forest.
There's nowhere to go but forward. I'm suspended from a cable high in the treetops and struggling to insert my feet in a pair of dangling stirrups - the only way I can propel myself across the yawning chasm between one tree and the next.
This is my third circuit, each more difficult than the last, and my courage is starting to flag. With one final, graceless, muscle-burning effort I clamber to the safety of the next ledge and find the next obstacle is an elevated scramble net, waving in the breeze 15 metres off the ground.
Although it's a bit hard to tell how many are there, by the sound of the voices up in the trees we've joined a big crowd at the TreeTop Adventure Park, in the Ourimbah State Forest on the Central Coast. Exercise at canopy level is a hugely popular activity in France, where it is known as acrobranching. In Australia, TreeTop Adventure Park is the only facility of its kind.
Opened in December last year, the course takes adventurers from tree to tree - at up to 15 metres above the ground - through a network oftightropes, rope bridges, suspended stepping stones, flying foxes and trapezes.
Climbers wearing safety helmets are attached to cables throughout the climb, using two carabiners: special metal clips used by cavers and rock climbers. All safety and other equipment are supplied and before going ape, climbers have to complete a safety induction, including practice sessions connecting and disconnecting their gear on a low-level test course. Then we're free to monkey around in the treetops.
I confess that I'm afraid of heights. Yet once I overcome my initial terror I find the course is an exhilarating experience.
There are five levels of difficulty, including a lower-height children's course designed for three- to 10-year-olds. Adults have to unhook themselves from one cable while hooking to the next but the children's course has a continuous belay system, similar to that used on the Harbour Bridge climb, so children cannot detach themselves by mistake.
After a nervous start, Alex, our five-year-old son, and his friends love the course. It's a bit too challenging for our three-year-old, Emma, and her friend, who twice have to be rescued by ladder-climbing staff.
For adults and older children, there are four graded high-wire courses, from the straightforward green course to the black one.
The park has 76 challenges high in the trees, including 12 flying foxes, and it takes about two to three hours to complete all four circuits, depending on your physical fitness and how many people are climbing at the time.
I don't start to feel the burn until we get to the red circuit, the third of the four courses, which underscores the minimal fitness needed to complete most of the park's activities. But by the end of the last red-level flying fox run through the trees, I'm ready for a cup of tea and a lie down.
Built in partnership with Forests NSW, TreeTop Adventure Park aims for minimal environmental impact. It has been designed so the platforms and other structures aren't drilled into the trees. All of the materials blend visually into the surroundings and it's easy to miss the park's unassuming entrance from the main road.
As if the thrill of tackling the challenges by day isn't enough, the park's operators have launched a world-first night course, , where the only light comes from the moon and miner's headlamps are worn by each adventurer. Those who've climbed the course at night say it is both chilling and exhilarating, especially the flying foxes and the Tarzan Jump. Scary enough in the daylight, the Tarzan Jump at night requires a big leap of faith in the darkness.
I'm not ready for the night course. I'll be back, however, to conquer the high black course - just as soon as I can move without pain.
TreeTop Adventure Park is about an hour's drive from Sydney, at 1 Red Hill Road, Wyong Creek, in the Central Coast's Yarramalong Valley. Open daily 9am-6pm. Book ahead to avoid disappointment. Bookings for night courses are essential, Adults, $36; children 10-17, $28; children 3-9, $18. Phone 4025 1008 or see treetopadventurepark.com.au.