Walk description

This track is closed until further notice due to the extensive road works near the summit of the Rimutaka Hill Road (SH2).

• 1 hour return
• strenuous

 The Rimutaka Trig Track gives the easiest access in the Wellington region to a wide variety of native subalpine plants. Six interpretive sites along the track are described below. Each is indicated by a numbered peg. See the map for thelocations of the individual sites.

1. Low forest

The more sheltered lower portion of the track passes through low forest with a stream close by. Compared with the rest of the track, this is a more favourable site for forest to re-establish. The main canopy tree is kamahi (Weinmannia racemosa), along with tall manuka (Leptospermum scoparium), five-finger (Pseudopanax arboretum) and broadleaf (Griselinia littoralis). Note the size of the kamahi trees and their leaves, then compare them with the stunted specimens which you will find at site 4 (see map).

2. Silver beech and shrubland

Silver beech (Nothofagus menziesii) would have been a common tree in the original forest that covered this site before the fires. This wind-sheared specimenis probably more than 50 years old (note the base which is at least 20cm in diameter) yet it is still only the height of the surrounding shrubs. Here the shrubs are tightly packed to provide mutual protection from the northwest winds. There are few gaps in this ground-hugging cover of stunted broadleaf, manuka, shrubby Coprosma, Hebe stricta, and two shrubby 'tree daisies', heketara (Olearia rani) and O. arborescens, each a mass of white flowers in spring.

3. Divaricating shrubs

'Divaricating shrubs' is the name usually given to a puzzling shape adopted by many of New Zealand's native plants. These shrubby forms have a densely-interlaced network of highly-branched twigs which only carry very small leaves. Two divaricating species are found at this site - Raukaua anomalaand Coprosma rhamnoides, each hardy and able to withstand the climatic extremes.

Manuka is still widespread but has become quite stunted compared with the lower sites. Mountain flax (Phormium cookianum) is now common and more light can reach the ground surface, allowing a profuse mat of Lycopodium club moss to develop and silvery carpets of Stereocaulon lichen to line the rocky sides of the track.

4. Snow grass

The gully below you contains many conspicuous large tussocks of a snow grass with large seed heads. This is a 'forest-dwelling' species (Chionochloa conspicua) of the snow grasses which are a feature of the low alpine parts of the southern Tararua Range. The snow grass probably prefers the moisture and better soils of the gully. Like the other plants on this mountain slope with parallelveined 'grass-like' leaves (the flaxes, Astelia nervosa and A. fragrans, and the cabbage trees Cordyline banksii and C. indivisa), its tufted shape is ideal for withstanding the severe winds. Note that the kamahi is reduced to a series of small-leaved shrubs which hug the ground as a carpet (compare with site 1).

5. Inanga shrubland

Here inanga (Dracophyllum longifolium) dominates the vegetation. The erect tips of the inanga leavesbecome quite red in autumn and winter and impart a welcome warmth to the slopes. Looking back from this point, the remnant silver beech forest can be seen on the ridge to the west and pockets can be seen regenerating to the north across the Rimutaka Hill Road. In summer, a number of flowering herbs shelter among the shrubs - gentians, eyebrights, and orchids (especially species of Microtis and helymitra).

6. Rimutaka Trig

The rocky summit of Rimutaka Trig provides an outstanding view of the Wairarapa Plain and the Aorangi Mountains to the east. The trig marks the northern end of the Rimutaka Range, the southernmost of the line of uplifted ranges that form the backbone of the 'Fish of Maui' (Te Ika a Maui), that part of the North Island running from the Raukumara Range near East Cape to Cook Strait. The Ruamahanga River and Lake Wairarapa occupy the lowest part of the down-faulted depression beyond the Wairarapa Fault which cuts across the eastern base of the Rimutaka Range.

Note the thick tall shrubland on the shadier southeastern slopes below the trig. On the exposed Upper Hutt side of the trig you can see the wind funnelling effect reflected in the parallel lines of shrubland. In addition to the shrubs indicated at the other sites, this site carries small shrubs of the bush snowberry Gaultheria antipoda - a mass of red fleshy berries in summer - and the mountain cottonwood Cassinia vauvillersii. The mountain daisy Brachyglottis lagopus, with its attractive yellow flowers,is also a feature of this site in summer.