Dun in a Day
16 August 2023
Great Rides App – Dun Mountain Trail
Story Gary Patterson Photos Gary Patterson and as credited
Dun in a day? Well, this is a welcome change from the multi-day mountain-bike rides I had undertaken to collect data for the Great Rides App. Not only is it a day trip; the Dun Mountain Trail is a glorious loop! Few of the 22 NZ Great Rides are single-day cycling trips and most of the trails are either lineal or network layouts. So, after arriving in Nelson, I was really looking forward to the simplicity of riding the only Great Ride that is both a loop and day trip.
Simplicity though, does not mean easy-peasy. While it is simple to pedal out of central Nelson, the 17-kilometre hillclimb rising 900 vertical metres above Tasman Bay is a challenge that will keep me busy for the next few hours. My climb is made easier with heritage seemingly pulling me up the benched track, much like wagons were drawn up by horses that once worked this line. I say ‘line’ because the trail formation is on NZ’s first railway line, built in 1862. Horse-drawn empty wagons were pulled up the mountain to the mineral belt above, which is where I am heading. In some places my tyres bobble over a railway sleeper or two – the last remnants of the 20,000 timbers that once supported the now-disappeared iron tracks.
The former railway line unlocked mineral resources on the mountain top. As I swing around a corner I find myself running parallel with a modern, flash-looking fence line that locks out predators. This is the tall boundary fence of the Brook Waimarama Sanctuary, a community-based initiative that creates a pest-free wildlife reserve near the heart of Nelson. At times the trail runs right beside the 14-kilometre predator-proof fence that protects all sort of native wildlife. I enjoy peering into the sanctuary as I climb through the forest high above the city. The forest here is dense, lush and massive, giving the trail a real sense of remoteness despite being on the fringe of the town belt. The trail explores the dark recesses of the hillside where I ford small creeks before continuing up, up, up into the clouds.
I pass a few historic points, including the sites of former railway houses now reclaimed by the forest, before reaching an aptly named Windy Point. Crikey! Make sure your helmet is strapped on tight here, folks. This is where the trail breaks out of the forest and I am exposed to the full power of the natural elements of both geology and meteorology. The elevated view stretches out west over Tasman Bay. No longer protected by the forest, my body sways in the gale as the wind forces its way through the bend at Windy Point. Geology bares its pale orange face too, as I have reached the Dun Mountain Ophiolite Belt. Ophiolite (‘Ophio’ is Greek for snake, while ‘lite’ means rock) is formed deep in the earth’s mantle and has slithered its way to the surface via powerful tectonic forces. The same mineral belt sequence is found in Fiordland 700 kilometres south – the Nelson region having been displaced that far northward over geological time by the carving nature of the Alpine Fault shearing the earth apart. The land up here is almost devoid of vegetation, the iron and magnesium in the rock making the soils poisonous for most plant communities. The landscape makes interesting riding, offering a low-altitude sub-alpine experience as I ride towards Coppermine Saddle.
I enjoy the openness of the trail that winds along rocky faces towards the saddle. Upon reaching the high point I get off my own saddle to appreciate this north-facing viewing window. Straight ahead I peer down into the Maitai Valley where I can see the bike trail descend; to my left I can see a faint line in the hillside that once led to the mining area, and to my right is Dun Mountain (1129m) cloaked in a veil of cloud. Dun Mountain was named by early residents as a result of the hillside’s ‘dunn’ colour – an Old English term for dingy brown. In 1859 German–Austrian geologist Ferdinand von Hochstetter was employed by the government to map the geology of our country. He discovered that Dun Mountain was made up of dense igneous rock of olivine and chromite which he called dunite – a name now applied to all rocks of this type around the world. His discoveries and mapping resulted in von Hochstetter becoming known as the father of NZ geology. Today he has a mountain, an endemic frog, snails and takahē named after him. Interestingly, quite recently the mining of dunite to spread over land to advance its weathering has been considered as a potential method of capturing some of the growing global carbon dioxide levels in our air.
The former railway terminated at the saddle where I stand. Remarkably the line was built in one year by 200 men wielding picks and shovels … yet closed only four years later when the chromite was exhausted. The word chromite is taken from the Greek ‘chroma’ meaning colour, and at the time chromite was used for dye pigments; today we know it as the source for the thin shiny metallic coating on machinery called chrome plating. Turning to look back down the gradients I had just climbed, it would have made a thrilling gravity-powered ride for the brakemen on the descending ore-filled wagons. It took two-and-a-quarter hours to ride the wagons to Nelson – brakemen taking a shorter time could be dismissed. It is interesting to note that the trail has seen bike riders on its surface longer than it saw the ride of ore-filled wagons for which it was constructed. At least the line’s legacy continues.
Not keen on staying a moment longer with the air at the saddle starting to cool, I hop back on my bike and drop into the Maitai Valley. This section of trail is a grade harder than what I have experienced on the climb. I love the tight, twisty and technical descent. What an amazing job the trail builders have done over the years to create this cycle trail. Fabulous! While the former railway line provided a relatively good benched track to Coppermine Saddle (with a number of hike-a-bike spots on the open tops) it was not until early 2000 that pioneer mountain bikers started weekend works to cut a rough track down off the tops into the Maitai Valley. Their efforts were later supported by local bike clubs and councils who upgraded the track significantly to make it fully rideable. In 2011, the trail opened as the third Great Ride of the NZ Cycle Trail.
The descent is thrilling. It does not take long to reach the bushline where the trail starts to straighten up, and where my bike seems to have a life of its own picking up pace and jostling me in the saddle like riding an unbroken horse. The trees become a blur as I crank up a gear to enter cycling hyper-drive; my eyes start to water. These are tears of joy! I pass a junction to a limestone cave. Had I detoured I may have seen one of the rarest miniature snails (1.7mm by 1.2mm) in the world, endemic to only one small pond in the cave. However, my steed has other plans; I continue to hang on tight and frantically freewheel to the valley floor on one of NZ’s longest mountain bike descents. It’s good fun.
Then, suddenly, the gradient eases as I reach the Matai River and follow its flowing course downstream to the Maitai Dam. Once I pass the dam that provides the city’s water supply, urbanity starts to assemble with the occasional dwelling appearing in this scenic forested valley. I pass a sign to Tantragee Saddle, a shortcut on the loop, but I continue on, enjoying the trail beside the sweeping river bends. From here the ride is gentle, and I cycle carefree into Nelson past swimming holes before turning a bend to complete the ride. I stop to check my GPS units, save the data and note that the loop took me several hours.
As I rest at the trailhead and I scroll through my trip photos, I reflect on the memories I had just collected on this trail.
The Dun Mountain Trail is a complete day ride. Normally ridden in the direction I travelled, the anticlockwise loop has a gentler climb on the track of the former railway line. I enjoyed starting near the coast, leaving the city for the wild, and climbing the benched track of the former railway line that is steeped in history to reach the sub-alpine tops, before the descent to complete the loop. While an advanced grade trail, this has to be one of the easier rides in the country to go from sea level to the sub-alpine tops and is now my favourite day ride. What Dun had done for me is to leave a permanent grin on my face to carry me though my multi-day rides ahead. In my view, Dun equals fun and I will return to enjoy Dun in a day!
43km Advanced Trail (Grade 4)
Official Links: heartofbiking.org.nz/our-trails/dun-mountain-trail
Great Rides App: Use App logo and QR Code together
Article kindly provided by nztoday.co.nz
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