CUNNINGHAM: A CENTURY OF CHANGE IN RUAHINE RANGE FORESTS 11
A CENTURY OF CHANGE IN THE FORESTS OF THE RUAHINE RANGE, N0RTH ISLAND, NEW ZEALAND : 1870-1970
A. CUNNINGHAM
New Zealand Forest Service, Napier
SUMMARY: Botanists describing the Ruahine Range prior to 1920 made no mention of the forest debility described by later writers. In the 1870s and 1880s the lowland forests were cleared from round the southern half of the range and grazing commenced on the northern and western plateaux. Opossums (Tricho.surus vulpecula) were liberated in the 1880s and red deer (Cervus elaphus) first entered the range about 1900. By the mid-1920s deer had modified forests; in the northern part of the range. By 1940 deer damage was extensive and opossum damage had been noted. During the 1950s some forest canopies were severely damaged by opossums, and considerable forest collapse occurred during the 1960s. There has been subsequent recovery in some places and continuing forest deterioration in others.
INTRODUCTION damaged by bark stripping by the Maori, in earlier The Ruahine Range (Fig. 1) runs from near the times. Ngaruroro-Taruarau River junction in the north to Between 1845 and 1852 the botanist William Wharite Peak in the south, a distance of some 90 km. Colenso crossed the Ruahine Range several times, Since 1870 considerable changes have occurred in his usual route being across the northern portion the forests of the Ruahine Range. Throughout the of the Mokai Patea Range, over Puketaramea to range forests have been modified, largely by intro- Te Atua Mahuru, and down the Makaroro River duced animals, particularly opossums (Trichosurus to Hawkes Bay. In his published account of vulpecula), deer (Cervus elaphus and Cervus nippon), these journeys (Colenso, 1884) he included detailed and goats (Capra hircus). In many parts of the range descriptions of the vegetation. Although he men- forest deteriorafon has occurred, particularly since tioned encountering dead, decaying, and windthrown 1920. Deterioration may consist of a greatly reduced trees, and fallen logs in riverbeds, there is nothing shrub tier; the loss of ferns, moss, and humus from in his text to suggest any form of unnatural or the forest floor; or defoliation, death and collapse spectacular forest debility. On the contrary, he of the forest canopy. In a simplified form, the wrote eloquentiy at times on the richness and health observations of changes are summarised in Table 1. of the vegetation. No objective measurement of these changes was Wild pigs (Sus scrofa) were liberated in the North made before 1970, and this paper attempts to Island in the 18th century and by 1840 were describe the patterns of change by examining in probably established in the Ruahine Range area. chronological order the field descriptions recorded Colenso (1884) mentioned that pig hunting had been by various people who have travelled or worked in conducted on the flanks of the Mokai Patea prior the range. Throughout this paper botanical names to his visit in 1848. He also recorded the presence, have been brought up ,to date and measurements prior to 1850, of landslides on both sides of the converted to metric. range. Recent work by Grant (1965) and Stephens (1977) provides further evidence of periodic storm THE FORESTS PRIOR TO 1870 damage and slope instability in the Ruahine Range Maori habitation of the Ruahine Range appears during the past few centuries. to have been light and sporadic. Pre-European fires The forests of the Ruahine Range prior to 1870 occurred in several places in the north-west Ruahine may be regarded as having been largely uninfluenced Range from the Mokai Patea through to the by European man or his introduced animals. Pohokura basin. Some of the burned areas were near known Maori routes across the range (Elder, THE PERIOD 1870 TO 1920 1965). Batley (1956) found that totara (Podocarpus Between 1870 and 1920 the forests in the region totara) in the north-west Ruahine Range had been of the Ruahine Range started to undergo consider-
New Zealand Journal of Ecology 2: 11-21 12 NEW ZEALAND JoU RNAL OF ECOLOGY, Vo.L. 2. 1979
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AUAHINE RANGE
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FIGURE l. Map of the Ruahine Range. CUNNINGHAM: A CENTURY OF CHANGE IN RUAHINE RANGE FORESTS 13
TABLE 1. The main changes in forests of the Ruahine Range from 1870 to 1970.
Period Main changes Causes Pre-1870 Forest generally healthy and complete, Maori fires and barkstripping. with only slight modification. Erosion scars present. Rainstorms. 1870 to 1920 Clearing of foothill forests, and European fires; also of some parts of the range. sheep and cattle grazing. Opossums and red deer enter the range; sheep and cattle present. 1920 to 1940 Severe modification of beech forests. Deer. Goats noted in south; opossums noted in north. 1940 to 1950 Canopy defoliation in rata-kamahi forests. Opossums. Damage to kaikawaka. Deer. 1950 to 1960 Heavy mortality in rata-kamahi forests. Opossums. Reduction or elimination of understorey species throughout range. Deer, goats. Defoliation of red beech. Insects. Widespread ill-thrift of kaikawaka. Unknown. Increase in frequency of "slips". Forest instability. 1960 to 1970 Widespread collapse of former rata-kamahi forest. Death, decay, wind. Introduction of conifers and willows for erosion control. Concern for stability. Continuing ill-thrift of kaikawaka. Unknown. Continuing high incidence of slips. Forest instability. Some indications of forest recovery. Decline in deer numbers.
able change. In the south, extensive tracts of forest evidence that erosion and instability were features were cleared on both sides of the range, and by of the Ruahine Range before the deer build-up of 1900 the present pattern of farming in the Manawatu about 1920. Alexander McKay (1888) observed that and southern Hawkes Bay had emerged. Apart from the Mangaatua Stream used to spread widely when localised fires and incursions of cattle, the forest on in flood, and deposited large quantities of shingle the flanks of the southern Ruahines remained largely and boulders over the higher part of the alluvial intact. However, removal of forest from adjacent flat. In a later paper (McKay, 1900, he described piedmont fans prior to 1920 contributed to river large landslips in the headwaters of the Makaretu instability in this region in later decades (Mosley, River. Kennedy (1914) mentioned slips in the moun- 1978). In the north and west the easier and more tains as being a source of shingle in the Ngaruroro, open country was grazed from the 1880s and and Aston (1914) referred to the extensive shingle burning of the grass and scrubland, and some slips of the Ruahine tops. forest, was associated with this. A serious fire also Apart from the changes caused by fires and destroyed much forest in the upper Tukituki localised storms there is no evidence that the (Moorcock) area in the 1880s (Elder, 1965). Ruahine forests were seriously damaged or Opossums were liberated in the Pohangina Valley unhealthy before 1920. Two well-known botanists, in 1883 (Pracy, 1962). During the same year red B. C. Aston and F. Hutchinson, spent three days deer were liberated at Matapiro, about 25 km east in the Makaretu headwaters in 1913 and crossed of the north-eastern Ruahines (Logan and Harris, the northern Ruahines near Colenso's route in 1967) and probably entered the Ruahine Range January 1914. Aston made a solo trip to Wharite about 1900. By 1918 deer were common in the Peak two months later (Aston. 1914). Although they northern Ruahines (Elder, 1957). Further red deer had observed kamahi (Weinmannia racemosa), rata liberations were made on the western flanks of the (Metrosideros robusta), tree fuchsia (Fuchsia range between 1902 and 1922. Although some of excorticata) and kaikawaka (Libocedrus bidwillii, all the Ruahine erosion has been attributed to the of which showed widespread mortality or ill-thrift development of high deer populations, there is also 50 years later, they made no mention of any 14 NEW ZEALAND JOURNAL OF ECOLOGY, VOL. 2. 1979 damage. In fact, Aston (1914) noted that at 823 m occurred on flats down the Waikamaka; on one on the Mokai Patea ridge such plants as tree fuchsia, such flat under red beech the following description broadleaf (Griselina littoralis) and lacebark (Hoheria was made: ". . . practically all undershrubs except sexstylosa) ".. . flourish in a marvellous manner." ee fuchsia, Coprosma rhamnoides and Pseudo- Given the observational powers of Colenso, panax anomalus have been killed; mahoe (Melicytus Hutchinson, and Aston, and the fashion in those ramiflorus) and broad leaf torn to the ground; days towards written detail, it is difficult to bel:eve fivefinger (Pseudo panax arboreus) barked completely that such forest debility as was later described to 1.5 or 1.8 m in height and of course dead; a could have escaped notice or gone unrecorded. It scene of desolation. A few minute herbs and the must be concluded that before 1920 the Ruahine grass Microlaena avenacea remain on the forest Range forests were generally in a healthy condition. floor." Kean and Newcombe (1937) described in con- THE PERIOD 1920 TO 1940 siderable detail the destruction by deer of kiokio By the mid-1920s there was a high deer population (Blechnum capense) and the importance of its on the northern Ruahine plateau. At that time rhizomes in stabilising loose slopes, and stated: (Elder, 1965) the forest floor was bared, roots were "On one place where recent slipping had occurred exposed, and by 1932 the mountain beech (Notho- on previously fixed steep scree slopes the area fagus solandri var. cliffortioides) forest was already immediately adjacent was found to still have traces a shell on the slopes of the north-eastern plateau, of the fern on it. It may be safely assumed in this which was the area of the densest deer population. case that deer had been responsible for the Nearly all undergrowth had then been browsed out commencement of the slipping." They described deer in some basins. Elder (1965) also reported that by damage to sub-alpine scrub as particularly severe, 1935 there was sign of deer along the whole line and noted browsing on tutu (Coriaria sp.), mountain of tops from the Ngamoko Range to Kereru. flax (Phormium cookianum), koromiko (Hebe High deer populations dur;ng the period 1930 to salicifolia), Coprosma robusta, Senecio elaeagni- 1940 arrested beech seedling development in the folius, and Astelia nervosa. Aciphylla plants were north-eastern Ruahines. This was demonstrated by particularly badly damaged and it appeared as W!ddowson (1960) after a study of age-class though many would die. Pseudopanax colensoi was distribution of mountain beech and red beech in many cases killed, while "mountain wineberry" (Nothofagus fusca) pole stands. (Aristotelia fruticosa?), and broadleaf ". . . were Photographs of the Mangapuaka (Kumeti) Stream badly knocked about." They described groups of taken in the mid-I920s and in 1936 illustrate that trees and shrubs which had been killed by the forest canopy had an unthrifty appearance in ringbarking, including ". . . Pseudopanax colensoi, those years. Mosley (1977) quotes the photographer broadleaf, "mountain wineberry", Senecio elaeagni- (Mr G. Miller) as recalling that the forest under- folius, Hoheria populnea, and Pittosporum rigidum." storey was more open in the early 1930s than Kean and Newcombe also referred to an unusual in 1977. This suggests that the canopy, though prevalence of tree mortality in mountain beech unthrifty, still provided a substantial cover. forests of the Waikamaka and Kawhatau which In 1937, R. Kean and F. Newcombe of the they attributed to causes other than deer. They Department of Internal Affairs crossed the range speculated on the possibility of fire or insect via Waipawa Saddle and the Kawhatau and Wai- damage. kamaka headwaters and were in no doubt about The Department of Internal Affairs carried out the severity of deer damage. They noted (Kean the first Ruahine deer destruction operation in the and Newcombe, 1937) that in the head of the summer of 1938-39, killing 4718 deer. Reporting Waikamaka large tussock grasses amongst fallen on this in 1939, Field Officer E. B. Davidson com- timber in the bush had been entirely eaten and they mented "It was found that certain portions of the observed that Pseudopanax colensoi and Senecio bush, such as the Gull Stream, Big Hill Stream, elaeagnifolius plants had been killed by heavy deer Koau Stream, and the Mangatera River with its browse. They recorded that in a forested flat in tributaries were pretty well eaten out by deer; the the Kawhatau headwaters all leaf mould had Kawhatau not so much, and progressively less in van:shed from the forest floor, the roots lying on the rivers to the south of the Kawhatau." Near bare sand and shingle. All the ferns were gone, the Lake Colenso ". . . the bush is completely bare of only trace being small stumps, probably of Poly- any undergrowth in the lower portions, and I have stichum vestitum, and all undershrubs were killed, never seen so much damage done in any part of many having been de-barked. Similar damage even the South Island bush." He noted that opossum 15 CUNNINGHAM: A CENTURY OF CHANGE IN RUAHINE RANGE FORESTS signs were seen in quantity in forests in the had suffered considerably from the inroads of deer. Mangatera Valley, especially near Lake Colenso, Ample indication of the presence of opossums was and also on the eastern side of the range north of also clearly visible. In 1953 an anonymous writer the Waipawa River. quoted Mr A. P. Druce as reporting that: "Round the base of the cliffs (of Mount Aorangi) appears THE PERIOD 1940 TO 1950 to be a favourite haunt for deer, which have done In 1940 botanist A. P. Druce noted that kamahi considerable damage to the flora there." (Anon, along the track up to Wharite Peak appeared to 1953). be in poor condition, but at that date the possibility In the southern Ruahines in 1951, Elder observed of defoliation by opossums was not considered heavy mortality of rata in the Tamaki valley and (Elder, 1958). noted that by 1952 canopy defoliation was becoming A brief (one page) account of the Ruahine conspicuous from the plains (Elder, 1958). Pracy vegetation was published in a Wellington Botanical returned to the southern Ruahines in 1953 and considered Soc:ety Bulletin in 1944 and although a paragraph that opossum distribution was complete is devoted to the kamahi-rata-rimu (Dacrydium throughout the area and that they were at peak cupressinum) forests of the southern Ruahines, no density in some localities around the lower forest mention was made of any sign of ill health. fringe. There was also increased deer sign (Pracy, 1963). He Similarly, kaikawaka and pink pine (Dacrydium made a further survey in 1955 (op. cit.) biforme) are mentioned without any comment on and noted severe defoliation extending throughout ill health. the forest. A further nine plants were added to his The first report of damage to kaikawaka come list of species which could be killed by repeated From Department of Internal Affairs Field Officer defoliation. They are: rata, tawa (Beilschmiedia A. Douglas who in 1947 wrote of the Mangatera taw a), mamaku (Cyathea medullaris), hekatara catchment: "The largest stand of kaikawaka in the (Olearia ram), raurekau (Coprosma australis), moun- Ruahines grows here; deer do not eat it but use tain totara (Podocarpus hallii), pokaka (Elaeocarpus the young whippy trees for antler rubbing." Douglas hookerianus), Senecio elaeagnifolius, and Olearia also described heavy deer use in the Ikawetea: arborescens. He recorded moderate to heavy damage "Both sides of the river are covered with beech on mahoe, hinau (Elaeocarpus dentatus), pate (Schefflera (Nothofagus) and the undergrowth is eaten right digitata), Pseudopanax simplex, rata vine out." (Metrosideros fulgens), bush lawyer (Rubus aust- In 1947 another Field Officer, L. T. Pracy, ralis), supplejack (Rhipogonum scan dens), and inspected the southern Ruahine Range and reported kaikomako (Pennantia corymbosa). He also observed heavy opossum populations in the lower reaches a severe attack of white scale insect (Anoplaspis of stream catchments and around the periphery of metrosideri) on rata in the Tamaki catchment. Opossums the range (Pracy, 1963). He also reported the were noted as be~ng in poor condition in presence of goats, cattle and deer in various catch- many catchments, with animals feeding in daylight, ments. He noted "considerable" defoliation of the and dead animals found. In some catchments canopy in some lower catchments and made the there was extensive bark biting of peppertree following list of ". . . species recorded as killed by (Pseudowintera colorata). These various observations constant defoliation": tree fuchsia, wineberry suggest that in the mid-1950s the opossum (Aristotelia serrata), tree tutu (Coriaria arborea), population in the southern Ruahines had exceeded fivefinger, kamahi; lace bark, rangiora (Brachyglottis its food supply and that animals were utili sing a repanda), toro (Myrsine salicina), Senecio kirkii, wide range of foods intensively in the competition raukawa (Pseudopanax edgerleyi) and titoki (Alec- for survival. Subsequent events indicated that this tryon excelsum). He recorded severe defoliation on was the period of demise of large areas of kamahi- nine other species and light defoliation on a further dominated forest canopy of mid-valley slopes. five species. Pracy returned to the southern Ruahines Further north Kelman and Kelly (1953), after a soil in 1949 (op. cit.) and noted an increase in the extent conservation survey of the upper Tukituki, also of foliage damage and also noticed more sign of commented on the changes wrought by deer: "The deer and goats, the latter being numerous in composition of the forests has changed considerably favourable habitats. s:nce the introduction of deer and other wild- life. Many species have virtually been eliminated, including tree fuchsia, wineberry, and various THE PERIOD 1950 TO 1960 species of Coprosma, Uncinia, and Pseudopanax. In 1950 R. A. Batley, after inspecting the western This reduction of secondary species has resulted slopes of Aorangi, noted that the forest undergrowth 16 NEW ZEALAND JOURNAL OF ECOLOGY, VOL. 2. 1979 in the opening up of the forest beneath the By the mid- I 950s opossums were cstablishe1I up canopy , ..". to timberline in forests of the Tukituki catch1licn1. Not all chnnge was atcributed to animals. N. L. Grnnt (1956) described intensive bark chewing by Elder was actively observing and recon.ting in the opossums on red beech and miro (Potlocarp11s 1950s nnd in an early report (1955 ) he referred to ferr11gi11e11s), and on mou11t11 in beech up to 920 m. mountain beech timberline retreat and to a general leading to dead foliage on affected brnnches. In deterioration in mountain beech forest, and sought Lhe same year, Elder ( 1957a) observed opossum to relate these phenomena 10 chan_gcs in climate or b-rowsing in subo lpine scruh at 1250 m in the Oroua microcll111atc. The c oncept was further developed headwaters. During the winter of 1958 abundant in his 1965 pubEcatioo, and he concluded that 11 opo~um sign was repealedly recorded along the considerable amount of the vegetation change hr1d Ruahinc R:1 ngc l(lPS at the 1220-1370 m level from occurred during the past 200 years. About the Nomans Hut lo Howletts Hut (Elder, 1960b). m,d-1950-s he al~o SlMfcd rcpo,·ting widespread On the Wc$itern side of the range. Jackson ( 1957) bearlroL in kaikawaka, and a general absence c:,f noted 1hat in the W11 ikamak:a cacchmcnt opossums seedlings or saplings in tJ1e upper part of the had praclically elimina ted Pse11dop(l1u1x species :-t lliludinal range. A high proportion of. dead crowns (e.xccp t P. si11 ,._.fairiiJ and they l'\ppenred to be largely was noted in some areas of kaikawalca or concentrated in gullies (where tree fuchsia w:1s being kaikawaka-red beech forest. One of Eider's com rapidly killed out) and io wincberry areas along panions described the si1ualion succinctly (Jackson, 1he clisturbeo forcsr margins. He also described 1957): "Much of the red beech above 975 m is localised intensive deer browse on one site on the ovcrmaturc. stagheaded. and frequently dead. On Mokai J>ntea Range: ". . . all young beech are the southern face of T i1npu the ca nopy cover is clipped close: larger trees have their laterals frequently Jess than 25 'X, . The slopes from Colcoso reduced 10 stubs; Pseudo1,a11(1x species l!nd the down to the Kawhatau River show poor regenera preferred coprosmas have been eliminated: PoJy tion, largely due to a very heavy ground cover of .r,id//lm lefl as residual tufts; Copro.tm "Abundant dead kamahi, rata, fuchsia, and wine- He noted that for some localities, however, deer berry. Defoliation and bark chewing also noted on damage was only part of the story. mahoe, lacebark, hinau, tawa, hekatara, and maire After an inspection of the Pohangina catchment (i.e., Nestegis sp.) (Cunningham, 1971). in 1966, McKelvey (1966) noted the importance Elder (1957a) noted a characteristic paucity of of deer in preventing recovery of slip faces : "Noxious bird life in the Ruahines by comparison with the animals are precluding the revegetation slips by forest; their ranges further north, and viewed this as an important activities induce swards of grass and fern which are ecological factor in seed distribution and inadequate to stabilize the slopes and there is much evidence insect control. of old slips, now covered in grass and fern, becoming active Although much of the forest deterioration in the again. Nowhere was there seen old slips in stages Ruahines was attributed to opossums and ungulates, of reversion to high forest." the presence of rodents was not overlooked. A significant development of the mid-1960s was Elder (1957a) recorded large numbers of mice in the use of introduced plants for erosion control. A beech forests late in 1955, following a heavy seed small area near Pohangina Saddle had been planted faIl the previous autumn. Pracy (1959) took the rat with pines and spruces in 1953 but heavy browsing population into account when planning bait for a by deer, sheep and hares had prevented their large operation to poison opossums in the Opawe development. From 1965 onwards, poplars, willows, catchment that year, and EIlis (1960) noted the pines and other conifers were planted in the head- presence of rats and mice in the Makaroro forests. waters of southern Ruahine catchments, in an Defoliation of red beech by the caterpiIlar of attempt to arrest erosion. Similar planting was done Epichorz'sta emphanes was reported from various on a small scale in the Tukituki headwaters in the catchments (Oroua, Kawhatau, Tukituki, Ikawatea) late 19608. between 1956 and 1958 (N.Z. Forest Service, 1966). Elder (1965) drew attention to the common THE PERIOD 1960 TO 1970 occurrence throughout the Ruahine red beech During the 1960s the animal/plant relationships forests, of a predominance of large old trees form- became even more complex as forests recovered ing a discontinuous canopy. The forest floor is in some areas but deterioration continued in others. frequently dense with Dicksonia lanata or Blechnum However, a start was made towards quantifying the discolor and there is often a paucity of young changes. red beech trees or seedlings. Elder considered that The Forest Research Institute was active in the the Dicksonia lanata had only become widespread area about the beginning of the decade. In the since the introduction of deer. Although he noted summer of 1960-61 field parties collected data for that this dense fern cover inhibits seedling develop- the forest type maps subsequently published in 1970 ment he also pointed out that neither species of fern (Nicholls, 1970). Unpublished Forest Service reports flourishes in full sunlight and suggested that further from this period contain many photographs opening of the canopy would give rise to major illustrating forest deterioration (McKelvey, 1960; changes. In 1969 J. Ogden of Massey University Nicholls, 1962). In the following year plots were commenced a series of studies in this class of forest established throughout the range to monitor future on the slopes of Mt. Colenso, aimed at understand- changes in the vegetation, and during the course ing the mechanics of change. This work subsequently of this work comprehensive notes were made on led tcr; publications by Ogden (1971) and June and forest condition. These were later assembled in Ogden (1975, and 1978). unpublished reports (Wallis, 1966; Cunningham, Accumulated observations from the Ruahine 1966). Range in the 19608 made it clear that except in the The outstanding contribution of the decade was north-west, kaikawaka was generally unthrifty, that Elder's 1965 publication on vegetation of the heart rot was common even in young trees, and that range, in which he presented observations and re- seedlings were rare at altitudes above 1070 m. Dead cords accumulated over several decades. He trees were common, and in some areas whole stands had touched on the relationship between deer damage died: "The ridge dividing the north-west branch and slope instability and considered that in the of the Mangaatua from the Whareroa once carrieda Waipawa headwaters the increase of slip faces could kaikawaka-pink pine forest with a canopy at 6 to fairly certainly be attributed to deer. Slips frequently 9 m. These trees are now dead but still standing. started where deer had congregated on sunny slopes, The present discontinuous canopy is now 3 to their trampling destroying the moss and root cover, 4 m tall." (Cunningham, 1966). There is still no after which the exposed rock began to disintegrate. 18 NEW ZEALAND JOURNAL OF ECOLOGY, VOL. 2. 1979 clear explanation for the widespread debility of places: "Up Takapari from West Tamaki/Cattle kaikawaka. Creek Saddle-lower scrub line of kamahi, broadleaf, A heavy snowfall in the winter of 1961 caused Pseudopanax colensoi, leatherwood, fuchsia, pink considerable damage to western Ruahine forests pine; this heavily tracked and browsed by deer, from the southern Ngamoko Range to the Manga- many plants dying as a consequence. . . . Main tera. "Limbs and branches up to 15 cm diameter divide north of Wharite trig: leatherwood were torn off red and mountain beech, and to a association canopy intact, but shrub tier and floor lesser extent from kamahi, mahoe, fuchsia, and cover show serious damage from deer and goats. more rarely pink pine, Hall's totara and kaikawaka. Fuchsia present in gullies. South from Wharite trig In some places even sub-canopy peppertree was -cover of leatherwood (many dying) and peppertree damaged." (Cunningham, 1966). plus waterfern (i.e., Histiopteris incisa)/microlaena In a report on beech regeneration in cut-over interspersed by dead kaikawaka and dead or dying forest north of the Makaroro River, Ellis pink pine." (Cunningham, 1971). (1960) recorded ghost moth (Aenetus virescens), Cunningham (op. cit.) also noted that at lower the buprestid bark beetle Nascioides enysi and levels in 1962 forest deterioration was in some places Pseopholax sp. on red and mountain beech pole well advanced: "From Mid-Pohangina Hut east- stands and considered that they were responsible ward up spur. From 550 m to 600 m all kamahi for some mortality. He recorded Navomorpha dead, leaving a dense sward of Microlaena, sulcatum larvae defoliating wineberry, and Elder Blechnum discolor, Uncinia, and waterfern plus (1960a) also noted that insect damage to wineberry scattered broadleaf and occasional rimu. Above was extensive in this area. Nascioides enysi was 670 m most kamahi trees are still alive but the shrub found to be associated with damaged beech forest tier is seriously depleted, and the forest floor is bare canopy at lower elevations of Ohara Stream in 1961 except for scattered Blechnum discolor." (Wallis, 1966). Pook (1962) reported widespread In 1964 a helicopter flight in the Pohangina and mortality of red and mountain beech in the Maka- Oroua catchments provided opportunity for further roro headwaters. A wide range of size and comment: ". . . down Pohangina and round to dominance classes was represented, and Nascioides Piripiri, generally about 80-100 m above the river enysi was found to infest the underbark of all trees and slightly on the eastern side. Forest deterioration examined. (Later studies suggest that in such cases becomes increasingly evident on the mid and lower beech mortality may be attributed to Platypus rather valley slopes as one proceeds down-valley, but the than to Nascioides-Milligan, 1972). most striking features are the dead and dying beech In 1963 Pracy reviewed his earlier observations trees on most of the steep faces just above the river, of opossums in the southern Ruahines and and the riparian slip activity or poor condition commented that the situation there had been riverside vegetation. Seriously damaged forest aggravated by goats, cattle, pigs and deer. These continues round into the Piripiri headwaters. ground-browsing ungulates had, by depleting the Amazed at uniformity and severity of forest damage shrub tier vegetation and opening up tracks, in Coal, Cone, and Umutoi Creeks. The original improved access to food and nesting for opossums, high canopy has almost gone and is replaced by a and changed a relatively restrictive habitat to a lower vegetation itself severely damaged and in favourable one. In the mid-1960s there were still poor health. The predominant colour is not green, some palatable plants available for opossums, for but brown. This continues round the upper part of example Cunningham (1971) observed that there the southern Oroua catchment." (Cunningham, were still many pockets of healthy kamahi left in 1971). Elsewhere, (op. cit., p. 41) it was suggested the upper Pohangimi in 1966. that deterioration of the kamahi canopy was causing The southern Ruahines attracted increasing com- deterioration of associated emergent trees, due to ment and concern throughout the 1960s. After a exposure. reconnaissance flight over the range, Jackson (1961a) J. L. Nicholls (1970), writing explanatory notes noted: ". . . devastation by opossums on western to the Ruahine Forest Class map, included the slopes of the southern Ruahines on a most extensive following comments related to the southern scale from the Pohangina south. The leatherwood Ruahines: "Rimu-General Hardwoods: . . . in this (i.e., Olearia colensoi) belt of the southern Ruahines region most rata have died during the last 15 years, appeared to be virtually intact and conspicuously with many of the formerly abundant kamahi." And healthy." Ground inspection proved the latter to be ". . . large standing dead rata, among groves of generally true, but in 1962 even the leatherwood skeletal kamahi." Of the "Highland and Steep land belt was being penetrated by animals in some Softwoods-Hardwoods" which lie in the southern CUNNINGHAM: A CENTURY OF CHANGE IN RUAHINE RANGE FORESTS 19 third of the range his comments include: ". . . with tier was sparse or virtually absent, and the forest scaHered often dead or dying Hall's totara . . ." floor consisted of bare soil or greywacke parent and". . . large areas of standing dead kamahi." material. He reported that in the Ikawatea the forests During the 1960s descriptions of forest deteriora- generally were far from satisfactory and the scrub tion further north also occurred in many reports. hardwood forest of the gullies was in extremely Some examples follow. N. L. Elder visited Colenso poor condition throughout with heavy opossum Lake in 1961, and after describing the botany of the damage, running shingle common beneath the trees, lake region he commented: "Generally the area and active slips at higher levels. Cunningham (1966) appears to have had a long history of deer use and reported that during the summer of 1961-62 forest more recentiy of opossum. Dead fuchsia still stands, survey parties saw about 30 to 40 deer per day in most wineberry is dead, with heavily browsed the headwaters of the Makirikiri (a tributary of the survivors, and alliacebarks were hard browsed." A Ikawatea). little further south, Cunningham (1971) described There were, however, some indications of crossing the Pourangaki Valley to the Oroua recovery in the I 960s. Jackson (1961b) reported: in January 1962: "From Wooden Peg across "Considerable seedling regeneration and regrowth Pourangaki to Maungamahue. Leatherwood belt in of palatable species such as the broad leaved good condition, but below this the kaikawaka- coprosmas is apparent on the Waipawa terraces." kamahi belt has been completely opened up Keating (1964) described red beech regeneration by browsing and trampling; a few scattered, after logging in the Makaroro area, and noted that divaricating non-palatables form the shrub tier- it could be improved by machine scarifying, the floor a maze of bare tracks amongst a sward particularly just after seedfall. Cunningham (1971) of waterfern. Mountain beech on the steep upper described a 1964 visit to Opawe Ridge: "Up slopes is severely modified-only scattered pepper- Opawe Ridge to exclosure plots. Canopy fairly open tree in the shrub tier; considerable snow break to but in good health. Opossum sign not abundant. canopy, forest floor almost completely bare loose Around lower exclosure recovery is good; ground soil and rocks. Further down in the red beech/Hall's cover in particular is much improved, many totara zone the condition is better, with improved unpalatables and some palatables (mahoe, pigeon- shrub tier and ground cover, but canopy very open wood i.e. Hedycarya arborea, putaputaweta i.e. after the heavy winter snowfall. From Pourangaki Carpodetus serratus) up to knee or waist height all River up steep ridge to Maungamahue-red beech along track. Tawa seedlings and saplings are forest with canopy opened up by snow damage. thriving. Under the former kamahi forest (standing Light tracking; shrub tier of peppertree, wine- dead trees) is good growth of sedges and unpalatable berry, Dicksonia lanata, waterfern, and with spp., while inside the lower exclosure plot species fuchsia common in gullies. Upper valley slopes such as Cordy line banksii, C. indivisa, Coprosma with kaikawaka/mountain beech has been severely robusta, C. foetidissima, pigeonwood, and mahoe opened out and trampled by animals-looks like a are about 1.2 m high. Up to top exclosure plot the cattle yard! At the timberline is an area of 1 or canopy is more open-chiefly toro and peppertree, 2 hectares damaged by fire many years ago-50% a few kamahi still alive. Kaikawaka. mostly of trees are dead, and ground cover comprises unhealthy and regeneration of them absent, but short turf. Alpine grassland up to Maungamahue is seedlings of pink pine are common. On a 1969 visit in good condition, there are few slips, and several to the Pohangina, .Cunningham (op. cit.) noted that of these show signs of healing. Inspected northern- forest canopy on mid- and lower-valley slopes most headwaters of Oroua, just E of Maungamahue. appeared healthier probably because a lot of the Grassland and sub-alpine scrub in good condition, dead trees had collapsed. There was a warning note, upper forest of kaikawaka/pink pine with red however: "General impression of trends in the beech downslope, this very heavily browsed, tracked, Pohangina is that in spite of encouraging signs of and trampled. Shrub tier reduced to scattered improvement in the canopy cover, the former peppertrees, forest floor bare, many rocks exposed. stability provided by kamahi will diminish as the River headwaters heavily aggraded. Many tributary dead roots decay, and further-possibly extensive- rivulets in the upper headwaters are deeply incised slipping can be expected within the next two guts." decades. " Wallis (1966) described the red beech forests of the north-east Ruahines as being in very poor FROM 1970 TO THE PRESENT condition. Near their upper limits, in gullies and The period since 1970 has been notable for the on northern faces, regeneration was poor, the shrub quantity of written material on the Ruahine Range. 20 NEW ZEALAND JOURNAL OF ECOLOGY, VOL. 2. 1979 At least 48 reports (18 of them published) have ANON. 1953. The effort to preserve Aorangi. Forest and been produced since 1969 describing changes in the Bird 109: 7. vegetation and aspects of erosion. Most have been ASTON, B. C. 1914. Notes on the Phanerogamic flora written by Forest Service, Ministry of Works and of the Ruahine mountain chain, with a list of the Development, University, or Catchment Board staff. plants observed thereon. Transactions and Proceed- ings of the New Zealand Institute 46: 40-54. It is not intended to try and unravel the complex AUSTIN, N. J. 1975 (Unpublished). Tukituki River changes revealed by these reports. The generalisation headwaters-vegetation, animals, and erosion. New is that a new phase of growth has occurred Zealand Forest Service report. throughout much of the range, but that in many BATLEY, R. A. L. 1950. The food trough of Tarinuku. places forest deterioration is continuing and the area Forest and Bird 98: 5-6. of exposed subsoil and rock is increasing. BATLEY, R. A. L. 1956. Some practical aspects of Considerable progress has been made towards dendrochronology in New Zealand. Journal of the measuring forest condition and change, and in this Polynesian Society 65(3): 232-44. respect reports by James and Beaumont (1971), COLENSO, W. 1884. In memorium. An account of visits Austin (1975), and Cuddihy (1977) are major con- to and crossings over, the Ruahine mountain range, tributions. The studies by Ogden (1971) and June New Zealand, and of the natural history of that and Ogden (1975 and 1978) on beech forests region. Daily Telegraph. Napier. flanking Mt. Colenso have also added greatly to our CUDDIHY, M. J. 1977 (Unpublished). Forests, understanding of the mechanics of change. Since grasslands. 1975 monthly observations of kamahi forest have and animals of the southern Ruahine Range. New been made on two sites in the southern Ruahin~s, Zealand Forest Service report. and results indicate that once opened, the for~t CUNNINGHAM, A. 1966 (Unpublished). Catchment canopy can suffer sustained physical damage condition in the Ruahine Ranges, 1962. New from strong winds (Stoodley, 1978). From the Zealand Forest Service report. meteorological station at Wharite Peak we know CUNNINGHAM, A. 1971 (Unpublished). Field notes that the winds there are exceptionally strong and from the North Island ranges. 1959-1970. New Zealand sustained (827 km/day average). Mosley (1977; 1978) Forest Service report. reviewed the situation in the southern Ruahines in CUNNINGHAM, A.; STRffiLlNG, P. W. 1978. The terms of erosion and sediment, and Cunningham Ruahine Range. A situation review and proposals for and Stribling (1978) attempted a similar review for integrated management of the Ruahine Range and the range as a whole. the rivers affected by it. Water & Soil Technical Publication No. 13. DAVIDSON, E. B. 1939 (Unpublished). Ruahine Range- CONCLUSIONS report on deer destruction operations 1938-39. The main changes in the Ruahine Range forests Department of Internal Affairs report. from 1870 to 1970 are summarised in Table 1. The DOUGLAS, A. 1947 (Unpublished). Central North Island observational evidence suggests that although 1ong- deer district operations of 1946-47. Department of term climatic changes may have adversely affected Internal Affairs report. mountain beech and kaikawaka at high elevations, ELDER, N. L. 1955 (Unpublished). Forest typing, central the forests of the Ruahine Range were generally and southern Ruahine Range. New Zealand Forest in good health before 1920. Between 1920 and 1930 Service report. the influence of introduced animals became apparent, ELDER, N. L. 1957a (Unpublished). Ecological report and between 1920 and 1960 deer, goats and on northern and central Ruahine Range. New opossums had a profound and deleterious effect on Zealand Forest Service report. the forests throughout the range. In the southern ELDER, N. L. 1957b (Unpublished). Death of rata- Ruahines, opossums, in particular, severely damaged kamahi forest. New Zealand Forest Service report. the forest canopy to such an extent that wind-related ELDER, N. L. 1958 (Unpublished). Southern Ruahine physical forces have inhibited recovery. It is possible Range: ecological report. New Zealand Forest that. there has been an increase in the effects of Service report. fungal and insect pathogens as a consequence of ELDER, N. L. 196Oa (Unpublished). Makaroro mill these accumulated changes. workings. New Zealand Forest Service report ELDER, N. L. 1960b (Unpublished). Waipawa Forks- Smiths Creek. New Zealand Forest Service report. ELDER, N. L. 1961 (Unpublished). Colenso's lake. REFERENCES New Zealand Forest Service report. ANON. 1944. The vegetation of the Ruahine mountains. ELDER, N. L. 1965. Vegetation of the Ruahine Range, Wellington Botanical Society Bulletin No. 10: 5. an introduction. Transactions of the Royal Society of New Zealand. (Botany) 3(3): 13-66. CUNNINGHAM: A CENTURY OF CHANGE IN RUAHINE RANGE FORESTS 21 ELLIS, L. J. 1960 (Unpublished). 1959-60 Makaroro MCKELVEY, P. J. 1960 (Unpublished). Brief report on assessment, Part S.F. 24. New Zealand Forest eastern Ruahine protection forests. New Zealand Service report. Forest Service report. GRANT, P. J. 1956. Notes on opossum damage in beech McKELVEY, P. J. 1966 (Unpublished). Traverse of forests, Ruahine Range, Hawkes Bay. New Zealand Pohangina catchment, southern Ruahine Forest. Journal of Forestry 7(3); 111-13. New Zealand Forest Service report. GRANT, P. J. 1965. Major regime changes of the Tukituki MILLIGAN, R. H. 1972. A review of beech forest River, Hawkes Bay, since about 1650 AD. Journal pathology. New Zealand Journal of Forestry 17(2): of Hydrology (New Zealand) 4(1): 17-30. 201-11. JACKSON, D. S. 1957 (Unpublished). Forest recon- MOSLEY, M. P. 1977 (Unpublished). Southeastern naissance of Waikamaka-Mokai Patea-Kawhatau Ruahine investigation report on erosion and sedi- area. New Zealand Forest Service report. mentation. Manawattu Catchment Board report. JACKSON, D. S. 1961a (Unpublished). Flight recon- MOSLEY, M. P. 1978. Erosion in the south-eastern naissance; Ruahine and eastern Kaweka Ranges. Ruahine Range: its implications for downstream New Zealand Forest Service report. river control. New Zealand Journal of Forestry JACKSON, D. E. 1961b. (Unpublished). Northern Ruahine 23(1); 21-48. -forest inspection. New Zealand Forest Service NEW ZEALAND FOREST SERVICE. 1966 report. (Unpublished). Working plan for Ruahine State Forests JAMES, I. L.; BEAUMONT, P. E. 1971 (Unpublished). A 1964-69. New Zealand Forest Service report. survey of the vegetation of the southern Ruahine NICHOLLS, J. L. 1962 (Unpublished). Forest types of the Range. New Zealand Forest Service report. Ruahine Range. New Zealand Forest Service JUNE, S. R.; OGDEN, J. 1975. Studies on the vegetation report. of Mount Colenso, New Zealand. 3. The population NICHOLLS, J. L. 1970. Ecological survey of New dynamics of red beech seedlings. Proceedings of Zealand's indigenous forests. New Zealand Forest the New Zealand Ecological Society 22: 61-6. Service, Forest Research Institute. Mapping Series 6 JUNE, S. R.; OGDEN, J. 1978. Studies on the vegetation Sheet No. 13, Ruahine. (Ruahine Forest Class of Mount Colenso, New Zealand. 4. An assessment Map.). of the process of canopy maintenance and OGDEN, J. 1971. Studies on the vegetation of Mount regeneration strategy in a red beech (Nothofagus Colenso, New Zealand. I. The forest continuum. fusca) forest. New Zealand Journal of Ecology 2. The population dynamics of red beech. Proceed- 1: 7-15. ings of the New Zealand Ecological Society 18: KEAN, R.; NEWCOMBE, F. L. 1937. Investigation of 58-75. portion of Ruahine Range. Department of Internal POOK, E. W. 1962 (Unpublished). Notes made on the AUairs, extract from Annual Report for 1936-37. incidence of recent (1961) mortality of beech in the KEATING, B. 1964 (Unpublished). The effect of Makaroro River catchment. New Zealand Forest scarification on beech regeneration in S.F. 24. Service report. New Zealand Forest Service report. PRACY, L. T. 1959 (Unpublished). Aerial poisoning trial. KELMAN, E. H. H.; KELLY, D. 1953 (Unpublished). Soil Opawe-Mangatuatou Stream catchment, southern conservation survey of the upper Tukituki River Ruahine Range. State Forest 25. 3 Feb. to 10 Mar. catchment, Hawkes Bay, New Zealand. Ministry of 1959. New Zealand Forest Service report. Works and Development report. PRACY, L. T. 1962. Introduction and liberation of the KENNEDY, C. D. 1914. Shingle action in Hawkes Bay, opossum (Trichosurus vulpecula) into New Zealand and particularly as affecting the mouth of the New Zealand Forest Service Information Series No. Ngaruroro River. Institute of Local Government 45. Engineers Proceedings Vol. 2. PRACY, L. T. 1963 (Unpublished). Opossums; southern LOGAN, P. C. 1955 (Unpublished). Inspection report- Ruahine Range. New Zealand Forest Service District 2, Zone D. Department of Internal Affairs report. report. STEPHENS, P. R. 1977. Erosion in the upper West LOGAN, P. C.; HARRIS, L. H. 1967. Introduction and Tamaki catchment. New Zealand Society of Soil establishment of red deer in New Zealand. New Science. 25th Jubilee Conference Field Excursion Zealand Forest Service, Information Series, No. 55. handbook. McKAY, W. A. 1888. On the copper ore at Maharahara, STOODLEY, M. A. 1978 (Unpublished). Kamahi dieback near Woodville. New Zealand Geological Survey study, F.R.I. Project F 20/68, interim report. New reports of geological exploration 1887-88 19: 6-9. Zealand Forest Service report. McKAY, W. A. 1901. Report on a copper lode in the WALUS, F. P. 1966 (Unpublished). Report on a survey Ruahine Range, near Norse,wood. Appendix to the of the condition of the forests, scrublands, and Journal of the House of Representatives C-1O: grasslands of the upper Ngaruroro catchment. New 26-28. (Also: New Zealand Mines Record 4: Zealand Forest Service report. 415-17). WIDDOWSON, D. 1960. Beech regeneration and deer in the northeast Ruahine Range. New Zealand Journal of Forestry 8(2): 335-6.