Mt Hikurangi

Forest and Bird, Volume 18, Issue 1, 1 February 1987, Page 12

Mt Hikurangi

by

Ron Adams

Alpine Bastion of the North

jd Mz it memorable’’. These words have stuck with me as the mark of a good school field trip. Pupils these days are privileged with a variety of outdoor experience — sports and cultural trips, adventure camps and field studies. Parents and pupils are asked often to dig deep to finance trips and may question the value of getting out into wilderness areas to experience and appreciate their diversity and beauty. As New Zealanders we should have little trouble.organising memorable field trips; our land still has many unique pristine habitats which can provide excellent once-in-a-lifetime memories. Uniqueness is a sound and basic idea in the presentation of conservation and exploring unique places makes trips memorable. Let me take you to such a unique place. At the northern end of our mountain axis lies the fifth peak in the North Island, often assumed to be the first place in ‘the world’ to see the sun. This claim is based on the height of Mt. Hikurangi (1752m) and its nearness to the 180th Meridian and International Date Line. However, precise calcu-

lations taking into account longitude, latitude, elevation and time of year, suggest that high points on Mahia Peninsula and certainly some offshore islands (Chathams, Bounty and Antipodes) may see the rising sun first during the summer solstice. Fortunately the uniqueness of Hikurangi need not rest solely on this claim. None the

less, the rising sun really does produce an imposing shadow reaching high into the western sky on a hazy morning, for Hikurangi is a tilted buttress that stands alone against a backdrop of the main Raukumara Range of which it is a part. The meaning of ‘Hikurangi’ is sometimes given as ‘fishtail in the sky’ (Hiku, tail of a fish; rangi, sky), a

description similar to that given by Cook in October 1769 when he called it a ‘remarkable double peak’.

Amazement stirred

As our school minibus enters the Tapuaeroa valley five bumps of land stand tall (and very distinctive when mantled in winter

snow) above the surrounding lowland. They are Taitai (700m) in the foreground, Wharekia (1106m), Aorangi (1272m) the steep southern slopes of which form the Aorangiwai Scenic Reserve, and Honokawa (Whanokao, 1618m) which flank as it were, the more massive and central Hikurangi. The geology of this area is a source of intrigue

and apparently not well understood; hard weathered sandstones overly the softer siltstone and mudstone (papa) sediments which typify the East Coast. The scenery looks unlike anywhere else in New Zealand. An environment like this stirs up amazement and evokes the questioning mind — of young and old alike. Such thoughts are

seeds that generate both the ideas necessary for a good field study and also the appreciation and conservation mindedness necessary to preserve these monuments for future generations. The long walk up to the Gisborne Canoe and Tramping Club hut at 1100m from 200m in the valley below, is across land ex-

tensively farmed by Pakihiroa station. It is dominated immediately to the east by the sparsely vegetated conical rock and surrounding apron of unfenced indigenous forest which makes up Wharekia. Westward, the view of Whanokao bluffs and alpine shrubland colours slowly takes on an enormous silhouette as we rise above the low ridge separating us from that mountain. Above the 100m contour 4 km of northern rock face forms steep bluffs and scars interlaced with threads of leatherwood and speargrass. Half a kilometre of montane forest (100 percent silver beech canopy) separates the farmed land and the alpine scrub that predominates to the summit itself. Our studies at Mt. Hikurangi centre on silver beech and mass movements of the rocks and soils, so we have occasion to climb the 200m to the timberline several times and also survey speargrass distribution and species diversity among the alpine shrubs (checking out statistical methods we learned in class). Living at this altitude, we are building up an affinity for the land and plants here. We readily sense differences in aspect and altitude ourselves, and have a birds-eye view of the surrounding land. We learn to interpret the land: the growth forms of plants and the shapes of valleys and ridges. We begin to see patterns in the ecology of these plants and movements of the land, and wonder if we are on the right tack. Finally we can do some counts (and measuring), have a closer look, and check ourselves out.

Writing by candlelight

Evenings see us crowded around the small table by candlelight for 2-3 hours writing it all up and reading material we have brought with us to help. Never did we each fill three quarters of a 1B5 Exercise book in three days before. Steadily we are gaining an overall impression of the features which make our study area unique. Being the most northerly habitat for truly alpine flora in New Zealand (montane flora and some alpine species inhabit Te Aroha and Moehau further north) Mt. Hikurangi is the abrupt northern limit for many alpine species. Some of the large alpine flowers like the foxgloves Ourisia macrophylla and O. caespitosa, Gentiana bellidifolia, Edelweiss, the speargrasses Aciphylla colensoi and A. squarrosa have their northern limit here. Apparently the forget-me-not Myosotis amabilis is confined to broken shingle on the summit of Mt. Hikurangi. Leatherwood and snowgrass also have their northern limit here. So also do the montane plants Olearia ilicifolia and mountain beech. Since Mt. Hikurangi is the place in New Zealand where the timberline reaches its highest altitude, and Latitude 38°S generally marks the southern limit of so many of the subtropical elements in our flora, it would not seem unreasonable to expect some of our northern species to reach their greatest altitudes on this mountain. According to botanist Peter Wardle, four of our beech trees (Nothofagus fusca, menziesii, solandri, s. cliffortoides) are found together on Mt. Hikurangi and the fifth (N. truncata) is present on the neighbouring slopes of Whanokao.

In view of these known records alone we are surprised that some form of permanent protection has not already been secured for this unique mountain.

No beech seedlings

We further check out the effects of humans on this part of the biosphere (as the form 7 biology prescription dictates) and are amazed by what we see. Beech trees normally have about two good seed falls every ten years and this season is an excellent one, yet on the forest floor we are hard pressed to find any beech seedlings at all from previous years’ seed, even where there has been windthrow and sufficient light penetrates the forest floor. Cattle tracks are very evident throughout the silver beech and through the alpine shrubland. Through the leatherwood, cedar and divaricating coprosmas on the southern slopes of the mountain there is a maze of these tracks 20cm deep. Within 300m of the summit we disturb three sheep. Experience tells that such destruction of this unique alpine habitat will lead to accelerated erosion. Indeed, in 1947, a fire swept through most of the scrub on Hikurangi’s western slopes. This caused such severe erosion that a tarn was completely silted up within four years. Unfortunately this author had hoped that if the Raukumara Range became a Forest Park (it was gazetted in 1979) all of its unique vegetation types be preserved from fire, and other damage. In his description of a walk in to Hikurangi mountain in 1897, botanist James Adams relates "that the way up the mountain is over a landslip, and that save in the stream itself the soil is so loose that it makes the ascent difficult and the descent in some places really dangerous. The mountain itself seems to be rapidly falling away. Large slips appear on all sides of it, ending abruptly in precipices."’ The situation is not improved; the land here is very unstable, and depends on continued vegetation cover to remain intact. In addition to the erosion being initiated by livestock, it is apparent that the alpine vegetation is also being selectively grazed, the more succulent plants being cropped and the less palatable ones gaining dominance. No fences separate the farmed landbelow 1100m from the forest or from the alpine vegetation. Further to this anomaly,

the summit ridge of Mt. Hikurangi marks the boundary between the Raukumara State Forest Park to the southwest and the freehold land of Pakihiroa station to the northeast of the ridge. This must mean that half of the unique alpine ecosystem is legitimately grazed anyway. Though no fence prevents cattle from entering the S.F.P., the NZFS has recently announced its intention to begin another wild animal control programme in the Park. It is acknowledged that ‘‘the cattle are having a detrimental effect on the forest understorey, notably in the . . . Tapuaeroa valley and Mt. Hikurangi.’’ Reasons given why past culling of feral cattle was not continued were largely economic ones: ‘‘the meat was unsaleable’ the article said. Recently, however, the State Forests Scientific Reserves Advisory Committee have expressed concern about the damage being caused to vegetation by livestock and at the evidence of accelerated soil erosion probably caused by this grazing pressure. The committee has recommended ecological area Status for the State Forest portion of Mt. Hikurangi and I have been assured that investigations with the landowners on various methods of protecting land above 1300m are being made. The field work has come to an end. On returning home, young minds struggle to come to terms with conflicting ideas concerning a fleeting experience and lasting memories; concerning the grandeur of an ancient environment and the future rapid changes to that environment through continued grazing, possible clearing, erection of translators; concerning the enjoyment and learning experienced and the uncertainty that the same experience will be there for their children. To all visitors of Mt. Hikurangi today, the flora, fauna and natural landforms are not only unique but are of national importance and represent a coveted part of our national heritage. To the Ngati Porou of the East Coast, Hikurangi is also their mountain, their mana and much of their legendary past. The name Hikurangi is an ancient one that occurs in mythology; in the paridisial land of Hawaiki there is a mountain named Hikurangi which the light rests upon, a place of eternal life where death is unknown. In Aotearoa many prominent peaks were called after this first tapu mountain, with the mythic Hikurangi and the local one being closely associated or perhaps completely identified. Certainly this happened with Mount Hikurangi on the East Coast. . . In the 1930s a Pakeha trader travelling near this mountain found that the countryside round about was so seldom traversed as to be pathless, its only inhabitants innumerable birds and lizards that were believed to be spirits. As well, the summit was thought to be the home of a solitary moa, which stood there on one leg and fed on only the wind. (from The Natural World of the Maori, by Margaret Orbell (Collins). I write this with anticipation that some form of permanent protection such as the maintenance of adequate fencing adjacent to the indigenous forest or adequate boundary fencing at least can be agreed upon and be assured for this northern bastion of New Zealand's alpine plants. eo