Domestication of the New Zealand flora—an alternative view

NewZealand Journal a/Crop andHorticultural Science, 1992, Vol. 20: 257-2710114-067119212003-m57 $2.50/0 © The Royal Society of New Zealand 1992

Review

Domestication of the NewZealand flora-an alternative view

257

W.HARRIS*

P. B. HEENAN*

Botany InstituteDSIR Land ResourcesPrivate Bag, Christchurch, New zealand

*Present address: Native Plants and Animals Division,ManaakiWhenua, Landcare Research New ZealandLtd, P.O. Box 69, Lincoln, Canterbury, NewZealand.

Abstract We present some outcomes of attemptsmade to develop the economic uses of New Zealandplant species by their domestication, particularly withreference to a paper by Haase (1990) on the potentialplant genetic resources of the New Zealand flora.Particular attention is given to the development ofNew Zealand plants as ornamentals to illustrate thatconsiderable progress has been made in developingthe economic use of many New Zealand plants forgarden and landscape use. Haase's (1990) opinionthat the small number of cultivated plants derivedfrom the native flora is due to the short period ofhuman occupation of New Zealand is contradictedby the history of the development of introduced plantsthat has accompanied the conversion of large areas ofindigenous vegetation to pastoral, arable, and forestrysystems. Biogeographical factors, particularly theabsence of an indigenous land mammal fauna and amild oceanic climate, are suggested as the reasonswhy the New Zealand flora has not providedsignificant esculent plants. Reference is made to theintroduction of plants to Aotearoa-New Zealand byMaori and what remains of these introductions.Considerable scope remains for the exploration ofNew Zealand plants focuses other than food. However,market factors will remain as major determinants forany future development of economic products fromNew Zealand plants.

H92029Received 13 May 1992; accepted 5 June 1992

Keywords New Zealand; indigenous flora;biogeography; economic uses; plant domestication;ornamental plants; esculent plants; plant selectionand breeding; Maori; traditional uses; Phormium;Solanum; Cordyline; Broussonetia

INTRODUCfION

In a recent publication, Haase (1990) reviewed thepotential for development"of economic uses of theNew Zealand flora. In our view there are some errorsof fact and emphasis in this paper, and from ourstandpoint we would draw rather different conclusionsto Haase on both the extent to which domesticationhas taken place and on the reasons for the paucity ofesculent plants.

Haase (1990) gives the impression that the NewZealand flora has been subjected to little explorationand investigation as to its potential for economicplant products. He does not make reference to anextensive review on economic native plants of NewZealand in Economic Botany (Brooker et al. 1989),and a book on the same subject by these authors(Brooker et al. 1988) reviewed in Economic Botanyby Shultes (1990). This book contains 483 referencestowork: relevant tothe economic uses of New Zealandnative plants.

As the subject area covered in the article byHaase (1990) has already been comprehensivelycovered in the reviews by Brooker et al. (1988, 1989)it is not our intention to cover it again in detail here.Instead we intend to build on Haase's review bycorrecting errors of fact, by providing more up todate information on the outcomes of domesticationfor economic uses of native plants he refers to, and bydrawing attention to some of the key references whichprovide information on the physical environment andplant resource of New Zealand. This is needed tobetter understand the limitations and potentials offurther domestication for economic use of the NewZealand flora. Because of our special interest in theuse of native plants as ornamentals, we trace thehistory of development of this particular use in moredetail.

258 New Zealand Journal of Crop and Horticultural Science, 1992, Vol. 20

THE PHYSICAL ENVIRONMENT

The physical environment of New Zealand has beenwell characterised in numerous scientific publications,and this information has been collated in severalbooks. Examples of these books are those on climate(Gamier 1958), geophysics (Stevens 1980), geology(Gage 1980), geomorphology (Soons & Selby 1982),and soils (Molloy 1988).

The major fault zone that extends in a SW-NEdirection through both the South and North Islands ofNew Zealand is subjected to tectonic movementsover its entire length, and not just in the North Islandsection as stated by Haase (1990). Although thegeneral incidence offrost on the main islands of NewZealand decreases with decreasing latitude andaltitude, the northernmost region contained in theAuckland Peninsula is not, as Haase (1990) suggests,frost free. While the occurrence of frost in manycoastal situations of the Peninsula is negligible, itoccurs at levels in other parts of the Peninsula whichcan be damaging to frost sensitive plants (NewZealand Meteorological Service 1980). Harris &Decourtye (1991a) have shown that populationsfrom North Auckland of the widespread shrubLeptospennum scoparium JoR et G. Forst can toleratemild frosts and that there is a clinal increase in thecold tolerance of this species as the latitude andaltitude of origin of populations increase.

MAIN FEATURES OF THE NATIVE FLORAAND VEGETATION

Since Captain James Cook's first voyage ofrediscovery to New Zealand which arrived in 1769,there has been considerable foreign interest in, andscientific investigation of the flora and vegetation ofthe country. Cook, and the botanists on the shipEndeavour, took a keen interest in uses of the plantsthey found, and several were put to immediate use toprovide food, beverage, medicinal use, and shiprefurbishing. Others were transported back to Europeand quickly introduced into cultivation, mostly ashighly valued ornamentals. However, Joseph Banks,a member of Cook's voyage, noted in his journal thepaucity of esculent plants and fruits available to theindigenous Maori. The most important ofthe esculentplants he recorded were subsequently confirmed ashaving been introduced to New Zealand from tropicalPacific Islands by the Polynesian settlers of NewZealand. Banksnoted the value ofNew Zealand trees"fit for any kind of building" and emphasised thevalue of New Zealand flax (Phormium tenaxJ. R. et

G. Forst.) as a fibre plant (Brooker et al. 1988; Harris& Decourtye 1991).

The systematic description of the New Zealandflora was begun by the Swedish botanist DanielSolander, another member of Cook's first voyage toNew Zealand. His manuscript, Primitae Florae NovaeZealandiae, described some 360 species. Althoughthis work was not published, it was a source of namesand descriptions for later published Floras. Annals oftaxonomic research on New Zealand traeheophytaare given in the modem series of the Flora of NewZealand. These Floras have the objective of providinga definitive account of the indigenous and naturalisedplants of New Zealand (Allan 1961; Moore & Edgar1970; Healy & Edgar 1980; Webb et al. 1988).Ongoing work by both New Zealand and foreigntaxonomists is progressively refining the definitionof the country's flora.

Volume I of the series, which covers theindigenous tracheophyta except monocotyledons(Allan 1961), provides descriptions of 1457 species.Volume IV (Webb et al. 1988), which covers theequivalent groups of naturalised plants in Volume I,provides descriptions of 1470 species or speciesequivalents. Volumes II and III, which cover theindigenous and naturalised monocotyledons exceptgrasses, include 339 and 168 species respectively.The checklist for the .Grass Flora which is inpreparation, includes c. 190 indigenous and c. 220naturalised species (E. Edgarpers. comm. 1991). Aninteresting feature of the grass flora is that 66 of thenaturalised species are annual whereas all theindigenous species are perennial. As mentioned byHaase (1990), the overwhelming dominance ofperennial species is also a feature of the indigenousdicotyledon flora.

Inaddition to the indigenous and naturalised florasthere is a considerable introduced cultivated flora forwhich there is no comprehensive census. Althoughthe larger proportion of this cultivated flora consistsof ornamental species, it includes a significant numberof species of considerable economic value. Thesecultivated economic species, as well as the economicspecies which have become fully naturalised, providean immediate point of comparison with any attemptto economically utilise or develop products from theindigenous flora.The capacity internal toNew Zealandto develop plants for economic use has beendemonstrated for many species. Notable examplesfor the horticultural, forestry, and pastoral industriesrespectively are kiwifruit (Actinidia deliciosa (A.Chev.) C. F. Liang et A. R. Ferguson) from China(Warrington & Weston 1989), Monterey pine (Pinus

Ranis & Heenan-Domestication of the New Zealand flora 259

radiata D. Don) from California (Kininmonth &Whitehouse1991),and whiteclover(Trifolium repensL.) from Europe (Baker & Williams 1987).Researchand development earned out in New Zealand haslargely been responsible for these species providingproducts whichhave become internationalarticlesoftrade.

New Zealand taxonomists recognise thatknowledge of the country's indigenous flora is farfrom complete. Changes in the nomenclature ofindigenous New Zealand angiosperms and gymnosperms are recorded in a Nomina Nova series, themost recent in the series recording changes in theperiod 1960-86 (Connor & Edgar 1987). As well,there is an unpublished checklist of the indigenoushigher plants of New Zealand compiled by A. P.Druce which is widely circulated among planttaxonomists in New Zealand. The revision of thischecklistcompiled in July 1991lists 2414 taxa at thespecies level, and the calculated number of unnamedspecies is 470. It is estimated that the number ofindigenous plant species in New Zealand will cometo lie somewhere between 2350 and 2450 (A. P.Druce pees. comm. 1991), a number significantlyhigher than the 2000given by Haase (1990).

Explanationof thefactorsdetermining thenumberof New Zealand indigenous species is not as simpleas that put forwardby Haase (1990) viz. a lower thanexpected number of species relative to climaticvariation due to latitudinal and altitudinal rangesexplainedas due to thelong isolationof NewZealandfrom Australia and Antarctica since the UpperCretaceous. The reference to which Haase refers,Godley(1975),alsoincludestheexplanation providedbyMillener (1960)that the lowlandflora in particularwasdecimated in the glacial periodsbecause it couldnot move away as a consequenceof insular isolation.The effect of glaciation on the diversity anddistribution of theNewZealandflorahas beendebatedin recent years e.g., Wardle (1963),McGlone (1985).McGlone (1985), from the information that theindigenousflora is more diverseon theolder surfacesof New Zealand, gives more emphasis to tectonicexplanations.The relativeextent of edaphic variationin New Zealand, compared to other biogeographicregions,shouldalso be consideredas well as climaticinfluenceson the extent of speciation.

The absence of land mammals, apart from threespecies of bat, before the arrival of man late in thefirst millennium A.D.,both with respect to their foodpreferences and the disturbance they cause, is also alikelyfactorin the directionanddiversityof speciationof plants in New Zealand. The disturbance to

vegetation caused by man and the animals heintroduced provided niches for a large-scaleimmigrationandnaturalisation of plants.Esler (1988)considers thatNew Zealand's largestcity, Auckland,has the largest naturalised flora of any city in theworld.

The comprehensiveaccount of the vegetationofNew Zealand by Cockayne (1928) has a modemcounterpart in the book by Wardle (1991). Wardleincludes information on vegetation composedpredominantly ofnaturalised plants.andas wellbringsup to date the information Cockayne provided onindigenousvegetation.

Details in Haase's (1990) summary account ofthe vegetation of New Zealand which requiremodification are as follows. The native nikau palm,Rhopalostylis sapida Wendl. etDrude, and thekiekie,Freycinetia baueriana Endlssp.banksii (Cunn.) Stonedo not occur in the forests of most coastal regions asthey are absent from a significantpart of the coast ofthe southern part of the South Island. As well as theareas of indigenous lowland grassland that Haase(1990)indicatesas having beenconverted topasturesof introducedgrassesand legumes,considerableareasof other indigenous plant communities have alsobeen cleared for pastoral, horticultural, and exoticforestry uses important to the current economy ofNew Zealand. To the grass species Poa litorosaCheeseman and P. foliosa (HookJ.), which Haase(1990) lists as main species on the SubantarcticIslands,shouldalsobe added Ctuonocnloa antarctica(Hook.f.)Zotov which is importanton the AucklandIslands (Wardle 1991).

UTll..ISATION OF PLANT RESOURCESDURING THE POLYNESIAN ERA

Early Polynesian plant introductions

Rather than there being indications (Haase 1990), itis usually accepted that the Polynesian settlers ofAotearoa-New Zealand successfully introducedkumara or sweet potato (Ipomoea batatas (1..) Lam),taro (Colocasia esculenta (1..) Schott), uwhi or yam(Dioscorea sp.), hue or gourd (Lagenatia sicearia(Molina)StandI.), ti pore or cabbage tree (Cordylinefruticosa (1..) Chev. (syn. C. terminalis (1..) Kunth.)),and aute or paper mulberry (Broussonetia papyri[era(1..) Vent.).

The classic account of the Maori agriculturaluseof theseplantsis thatby Best (1925).AlmostcertainlytheMaori wouldhaveendeavouredto introduceotherplants from the Pacific Islands from which they

260 New Zealand Journal ofCrop and Horticultural Science, 1992, Vol. 20

migrated, butthe tropical characteristicsoftheseplantswould have operated against their chances of survivalin temperate New Zealand. The adaptation ofkumaraculture by Maori, to what are the absolute southerlylimits ofeven the most adaptable of tropical crops, isregarded as a considerable achievement (Yen 1990).It was Yen who in the 1950s assembled a collectionof more than 600 cultivars of sweet potato fromthroughout the Pacific. Four of these were consideredto be cultivars grown by Maori before their contactwith Europeans (Yen 1963a,b). Others were cultivarsintroduced by Europeans, adopted as crop plants byMaori, and given Maori names. A similar story appliesto the early introductions of potato (Solanumtuberosum L.) by Europeans, and several old varietieswere retained in cultivation by Maori and are nowknown by Maori names. The possible history ofintroduction of a kumara cultivar 'Waina', atransliteration of the "vine" characteristic of thiscultivar, is recorded by Berridge (1913).

Commercial growing of kumara in New Zealandat present is largely based on a mutant of 'Waina'named 'Owairaka Red' . In 1988/89 the New Zealandkumara industry produced 16000 t of roots from 640ha, 90% of the production coming from the region ofNew Zealand north of Auckland (Lewthwaite inpress).

Yen's sweet potato collection was transferred toJapan in 1966 when administrative decisions withdrewsupport for its maintenance in New Zealand. It wasan outcome of the resurgence ofconfidence by Maoriin their cultural heritage that the cultivars importantto Maori were "repatriated" in 1989 (Campbell 1988).However the agronomic characteristics of the "Maoricultivars" are such that they are unlikely to be able tocompete in commercial production with newercultivars. Further development of the New Zealandkumara industry will rely on the introduction ofcultivars which have been more recently selectedoverseas (Lewthwaite in press).

The hue is still grown and can be found for sale inmarkets in Auckland. Relics of the cultivation of tarocan still be found in the northern regions of the NorthIsland. Recent immigrants from the Pacific Islandshave used plants from this source, and also plantsfrom Tonga, to grow taro as a crop in the far north ofthe North Island. This has produced sufficient leaf forpreparation of a traditional Polynesian dish, but rootproduction has been unsatisfactory (Fale 1990).

It seems that the yam, uwhi, cultivated by Maoribecame extinct soon after European contact (Best1925), and the ti pore almost so. Walsh (1900) givesan account of plants of Cordyline fruticosa found at

Ahipara and Waimate North in North Auckland latein the 19th Century, and considered these were theonly known survivors at that time of theplant fonnerlygrown and known by the Maori as ti pore. EarlierCheeseman (1896) described the same plant fromwhere he saw it in the garden ofa MeReid at Abipara.Kirk (1898) described this plant as a new species,Cordyline cheesemanii, an error that was correctedby Walsh (1990).

It is not known whether these relics of ti poresurvive today. There is a plant collected as C.terminalis by Nancy M. Adams in 1961 from thegarden of E. Adams at Thames presently growing inthe Experimental Garden of the Botany Institute,DSIR Land Resources, Lincoln, which has as itsdetail of origin: "Garden plant believed to haveoriginated from those collected in the wild(?) NorthCape District, Cheeseman & Adams c.1897". (BotanyDivision Garden accession no. G2905, CHR 68997).E. Adams was the son of James Adams whoaccompanied Cheeseman on the expedition to theNorth Cape where the C. fruticosa at Ahipara wasencountered. However this living plant has smallerand narrower leaves, and lacks the distinct petiole,characteristic of C.frutieosa,given in the descriptionsby Kirk (1898) and Walsh (1900). It is also distinctlydifferent from a herbarium specimen of the plantfrom Ahipara collected by R. H. Matthews in 1899(CHR 295138) which conforms to the Kirk and Walshdescriptions. The leaf of the plant from the Adam'sgarden in Thames most closely resembles leaves ofC. rubra Otto & A.Dietr., a species often confusedwith two other Australian species, C. strieta (Sims)Endl. and C. eongesta (Sweet) Steudel (pedley 1986).Plants similar to these species are often seen growingin Auckland gardens.

Best (1925) recounts Captain Cook's encounterwith aute in the Bay of Islands in December 1769,and the remark in Cook's JournaI-"This plant mustbe very scarce among them, as the Cloth made fromit is only worn in smaIl pieces by way of Ornamentsin their ears, and even this we have seen but veryseldom."-indicates that it was very rare then.Probably the relics of these plants introduced by thePolynesians survived only a short time after thisencounter. The story of aute is curious becauseBroussonetia papyrifera is indigenous to regions ofJapan and China with winter climates considerablycolder than northern New Zealand where the speciescould be expected to grow well. Sykes (1969) givesan accountofsuccessfully growing plants from Japanoutdoors at PrebbIeton near Christchurch, and twopopulations from seed obtained from China have

Harris & Heenan-Domestication of the New Zealand flora 261

grown vigorously outdoors in the Botany InstituteGarden at Lincoln since sowing in 1987. This hasindicated these introductionsare well adapted to frosty,temperate climatic conditions. Sykes (1969)emphasises that aute is not a tropical plant and tendsto die out in hotter climates ifnot actively cultivated.A plausible explanation for the Polynesian introducedaute not thriving in New Zealand is that in its longhistory ofbeing carried through the tropical Pacific itunderwent selection that lost the cold resistance thespecies has in its natural area of origin.

Polynesian exploitation of the native flora

The extent of use by Maori of the indigenous florawas considerable and clearly was done with referenceto plant species they knew in the Islands from whichthey migrated (Best 1925; Biggs 1990). Doubling ofa name, which is a feature of the Maori names forseveral indigenous plants, is indicative of a plantbeing similar to a plant previously known (Biggs1990). For example, the Maori name kawakawa forMacropiper exelsum (Forst. f.) Miq. indicates, asmentioned by Haase (1990), Maori association ofthis plant with the related species PipermethysticumForst. f. which is the source of kava. Almost certainlyMaori would have investigated if kawakawa hadnarcotic properties, particularly as PipermethysticumForst. f. has been selected for different expressions ofthese properties in the various regions of the Pacificwhere it is grown (Lebot & Levesque 1990).

Haase (1990) mentions that the roots of thecabbage tree (Cordyline spp.) were a source ofcarbohydrate for Maori. Best (1925) documentsinformation on Maori use of Cordyline, and one ofthe indigenous species, C. pumilio Hook. f. wasdomesticated as a cultivated crop. Another cultivar,known to Maori as ti tawhiti, and documented byBest (1925), has recently been rediscovered by Harris& Heenan (1991) as a plant that was adopted at anearly stage by European settlers in their use of NewZealand plants as ornamentals (potts & Gray 1870).As ti tawhiti has never been observed to flower itstaxonomic status remains uncertain.

Carbohydrates were extracted from the youngstems as well as the roots of Cordyline australis(Forst. f.) EndI. in the form of fructose produced bythe hydrolysis of fructans through long steaming inlarge earth ovens called umu-ti (Fankhauser & Brasch1985; Fankhauser 1990). The extraction of the sweetcompound, called kauru, was an important activity ofthe Ngai Tabu tribe/of the Canterbury region of theSouth Island. There it was probably more importantas a confectionery and food flavouring to make other

vegetable matter such as fern root (Pteridiumesculentum (Forst.f. Cockaynej) more palatable, thanas acarbohydrate source.Fankhauser & Brasch (1985)considered that Cordyline australis warranted furtherinvestigation as a source of fructose and other byproducts including fibre and linoleic acid.

The statement by Haase (1990) that "Theindigenous food and fibre sources were almostcompletely abandoned after the introduction ofEuropean crops" is quite incorrect, particularly so forfibre plants. The commercial development of a flaxfibre industry is discussed later. The Maori usedmany other plants as sources of fibre in addition toPhormium tenaxJ.R. et G. Forst. and Cordyline spp.which Haase (1990) indicates as being "the almostuniversal fibre sources in Maori culture". Goulding(1971) lists 13 species of fibre-plants found in NewZealand archaeological excavations. Many of theseplants are used in contemporary Maori craft(pendergrast 1984). Plants most commonly used byMaori for fibre work at present are various varietiesof harakeke and wharariki (Phormium tenaxand P.cookianum Le Jolis) (Scheele & Walls 1988), kiekie(Freycinetia baueriana Endl. ssp. banksii (Cunn.)Stone),and pingao (Desmoschoenus spiralis (A.Rich.)HookJ.).

The statement by Haase (1990) that many nativeplants were utilised by Maori for their medicinalproperties needs to be qualified by differences ofopinion as to the extent of this use before and afterEuropean contact. Brooker et al. (1981) discuss thismatter and conclude that the old-time Maori usedexternal remedies, but use of internal medicines didnot become important until after European settlement.This was a factor of the introduction of diseases byEuropeans to which Maori had poorly developedresistance, and the consequent need to use Europeanherbal remedies and practices leading to theinvestigation of New Zealand plants for theirmedicinal properties. There remains a considerablerequirement for the authentication of the indicatedmedicinal properties of New Zealand plants, as veryfew have been subjected to appropriateclinical testing.

PLANT GENETIC RESOURCES OF NEWZEALAND AND OFFSHORE ISLANDS

The plants considered under this heading by Haase(1990) could be considerably extended by referenceto the work of Brooker et al. (1988, 1989). We addfurther information to that given by Haase forPhormium and Solanum bringing up todate thehistoryof the domestication of species of these genera. As a

decreased with increased tree density. The estimatedcost of a tree was Dfl 5.35 at 2000 treeslha and Dfl4.48 at 4000 trees/ha. The estimated cost of a stakewas Dfl 2.99 at 2000 trees/ha and Dfl 2.57 at 4000trees/ha. There was some evidence to suggest thatthiswas because ofdiscounts available for large orders.

A linear relationship was also evident betweenthe time (bIha) taken to plant the trees and treedensity/ha (Y =23.5 + 0.043X R2 =0.37, P < 0.01)(Fig. 4). Estimated planting time per tree decreasedwith increased tree density from 3.3 min at 2000trees/ha to 2.9 min at 4000 trees/ha.




correction, it is noted that the most importantremaining wild populations of Clianthus puniceus(G. Don) Sol. ex Lindl. are on the eastern part ofmainland North Island (Wilson & Given 1989), andnot on offshore islands as reported by Haase (1990).It is also noted that Tetragonia tetragonioides (Pallas)Kuntze, the New Zealand spinach which Haase (1990)lists as one of the four indigenous New Zealandplants which are cultivated for purposes other thanornamental use, has been sold in markets in the UnitedStates (R. L. Bieleski pers. comm. 1992).

SoUmumspp.

Haase (1990) makes mention of three species ofSolanum, S. aviculare Forst. f., S. laciniatum Aiton,and S. nodijlorum Jaq. indicating that they are widelyspread in New Zealand except for the extreme south.This is the information given in Allan (1961), but themore recent treatment of these species (Webb et al.1988) indicates that S. laciniatum occurs in the mostsouthern region of the South Island and also StewartIsland. The status of S. nodijlorum as an indigenousspecies is uncertain, and it is regarded as synonymouswith S. americanum Miller, which is also indigenousto America, Africa, South East Asia, and the Pacific(Webb et al. 1988).

Haase (1990) reports that "Solanum laciniatumand S. aviculare are now grown commercially inNew Zealand for the production of the alkaloidsoIasodine, which forms the base for steroid hormonesynthesis". The up-to-date information is thatsolasodine production from these species ceased in1981. The failure of this industry was largely theresult of the availability ofcheaper alternative sourcesof supply from synthetically produced steroids, andsoIasodine produced from Dioscorea batatas Decne.which was being sold on the world market by Chinaat half the New Zealand break-even price (WynnWilliams & Logan 1985).

The account of the research on the New Zealandspecies of Solanum from 1964 to 1982, and the briefperiod of commercial production from 1977 to 1981(Wynn-Williams & Logan 1985), provides a salutarywarning of the difficulties faced by attempts todomesticate and develop the plant genetic resourcesof New Zealand.

Phormium spp.

Brooker et al. (1988) provide a useful summary ofthe history of economic use of the New Zealand flaxspecies Phormium tenax and P. cookianum alsoknown by the Maori names harakeke and wharariki

respectively.More comprehensive accounts,reflectingthe considerable importance of Phormium fibre inthe economy of New Zealand in the 19th and early20th century, are given by Hector (1872)and Atkinson(1922). For a time in this period, flax fibre providedthe most valuable source of export income for NewZealand.

Maori used Phormium as their principle fibreplant. The Maori names, harakeke and wharariki, arecognative of the joined Polynesian names for speciesof Pandanus and Freycinetia. This indicates that theearly Maori recognised Phormium as having theproperties of these plants which they had used in thePacific Islands. Split green leaves were used to makekits, nets, mats, cloaks, sandals, ropes, carrying straps,and sieves. Dressed and dyed strips of flax weremade into decorative patterned kits and decorativetuku tukupanels for the ornamentation of buildings.The dressed fibre, obtained by hand-scraping, wasused to make fine mats and cloaks. Cultivars of thespecies were selected according to their suitabilityfor these different uses, and there have been stepstaken to identify and conserve these cultivars (Scheele& Walls 1988). Traditional Maori uses of flax arethriving today as part of the resurgence of the ethnicidentity and culture of the Maori people.

From c. 1820 flax fibre prepared in the traditionalway became an important article of trade as Maoriendeavoured to acquire goods offered for sale byEuropeans. This trade had a particularly significanteffect on the marked decline of numbers of the Maoripopulation in the course of the 19th century. ManyMaori shifted their habitation to less healthy locationsclose to the wetlands where flax grew naturally inabundance.This change of habitation increasedfurtherthe level ofmortality which was already high becausethe Maori population had not developed immunity tohuman diseases newly introduced to New Zealand byEuropean settlers. The trade in flax was closely linkedwith the trade in arms and ammunition which Maoriused in inter-tribal conflicts and in the wars withEuropean settlers. The efficiency of the newlyacquired weapons over traditional weapons furtherincreased the decline of the Maori population.

Throughout its history the economic viability ofthe New Zealand flax industry was markedlyinfluenced by international terms of trade. The earlyreputation of Phormium as a high quality fibre, basedon the material hand prepared in a very slow andlaborious way by Maori, was undermined by poorquality fibre produced by Europeans who imitatedthe Maori technique of preparation in unskilled andcareless ways. Although early attempts were made to

Harris& Heenan-Domestication of the New Zealandflora 263

mechanisethe processof preparing Phormium fibre,it was not until after 1860, when the outbreakof theMaori War markedly reduced trade production byMaori, that successful development of processingmachines occurred. There were several cycles ofprosperity in the industry, the last being during theFirst World War when in 1916 the greatestquantityof flax in the history of the trade was exported.However,by the generaldepression of the 1930stheflax export trade had virtually collapsed and neverrecovered.

Productionfor use in New Zealandof Phormiumfibre continued on a relatively large scale into the19708 with the last main area of productioncentrednear Foxton on the West Coast of the North Island.McLintoek(1966)recordsthatin the 1960satFoxtonthe fibre was manufacturedinto woolpacks, cardedhemp for the plasterers' trade, carpet underfelt,padding for upholsterers, and twine and ropemanufacture. The Phormium industry wassupportedby researchcarriedout by the BotanyDivisionof theNew ZealandDepartmentof Scientificand IndustrialResearch and the Department of Agriculture. Thiswasdirectedtoimprovequality control andprocessingtechniques, investigateby-productssuchas cellulose,ethanol, and fertiliser, and overcomepest problems.The devastation of the Phormium resource by theinsect transmittedyellow-leafdisease mentionedbyHaase (1990) was largely overcome by periodicflooding of the Phormium stands and selection ofresistantcultivars.It is certain thatbad themarketforPhormium remained viableitscropperformance couldhavebeen further improved.

Studiesin the 19708of alternative usesof thelandnear Foxton on which the Phormium was grownindicated that dairying provided a more economicalternative. Consequently a programme, completedintheearly1980s,wascarriedoutbytheNewZealandDepartmentofLandandSurveytoclearthePhormiumand drain the swamps to convert them to pasturesupporting dairyunits.An attemptwasmadetorevivethe Phormium industryon a small scale in the early1980s usingmachinery salvaged fromtheoldindustry,but fire destroyed the enterprise involved, BondedFelts Ltd, in 1985. Notes of an interview in 1985betweenBillHoskins,Managerof BondedFeltsLtd,and Richard Cassels, Curator of the ManawatuMuseum, Palmerston North, which are held by theMuseum, provide a brief record of the fmal years oftheflax industry. As wellascompetition fromcheaperimportednaturalfibres, whichHaase (1990)indicatesas the cause of the final collapseof the flax industry,competition fromsyntheticfibreswascertainlymore

important. Today,syntheticfibressubstitute manyofthe former uses of Phormium fibre. The historicalrecord indicatesthat the final blow to the Pharmiumindustrywas theinsistencebyJapanesepurchasers ofwool that wool packs made with Phormium fibrebesubstituted with packsmanufactured in Taiwan withsyntheticmaterial.

GENETIC RESOURCES OF NATIVE TREESFOR PRODUCTION FORESTRY

Haase (1990) observes that overseas visitors havecommentedon the apparent lack of interestof NewZealandforest scientists in selectingand developingsuitable indigenous treespeciesfortimberproduction.However, it shouldnot be taken from this that NewZealand forest scientists have not considered thispossibility and assessed the likelihoodof successofresearchto developthe wood production potentialofNew Zealand species. Brooker et al. (1988) in anoutline of the utilisation of native timbers in NewZealand, concludedby noting that in 1921 LeonardCockaynecommentedon the possibility of selectionfor improved timber trees after observing hybridsbetween theNewZealandbeech(Nothofagus) species.Because of the established economic value of thespecies,production forestresearchin NewZealandisoverwhelmingly dominatedby workonPinusradiata:However, work on the productioncharacteristics ofnative species has not been entirely neglected. andexamples, in addition to that of Wardle (1984)citedby Haase, are studies by Barton & Horgan (1980),Smale & Kimberley(1986), and Ledgard & Norton(1988).

We consider it unlikelythat the manipulation ofgenesofNewZealandtimberspecies tocontrol growthrate or to hybridise native and exotic species, assuggested by Haase, will result in tree selectionsimproving the economicsof their wood productionto a level comparable with that acheivedwith Pinusradiata and other fast growing exotic species.Although the prospect of increased use of nativespecies in plantings for production forestry is notpromising, therehas beenan encouraging increaseintheir use in revegetation and amenity plantings inrecent decades, and there has been some researchtowards aiding this use (Evans 1983;Pollock 1986).Several Department of Conservation nurseriesproduce large numbers of native plants for amenityandrevegetation plantings, payingparticularattentionto provenanceto minimisegeneticcontamination ofwild populations of plants, and providing plantmaterialsappropriate for successional plantings. The

264 New ZealandJournalof Cropand Horticultural Science, 1992, Vol.20

160 .,--~--~------~--~----------,

140

120

~'£;100"3(,)

'0 805)

..0E 60::lZ

40

20

o ~- Leptospermum6 - Metrosideroso - Coprosma

Fig. 1 Trends in the release ofornamental cultivars of NewZealand species of the generaLeptospermum.Meterosideros, andCoprosma.

2000198019601920 1940Years

19001880o t 0 e~ ~; 6: ~ I1860 .

sameapproach iscarried outby theAuckland RegionalCouncil Parks Department in their management ofextensiveforestparks in theregion.

NATIVE PLANTS WITH ORNAMENTALVALUE

New Zealandplantshave a welldocumented historyofcultivation asornamentals, andthisbasbeenbrieflyreviewed by Brooker et a1. (1988). Additionalinformation is presented here to enlarge theinformation presented by Haase (1990), as he doesnot adequately report on the achievements ofhorticulturists in developing the national andinternational use of New Zealand native plants asornamentals.

Important selection and breeding programmeshave been established for several genera that arehighlyregardedasornamental plants(Wratt& Smith1983). Theseprogrammeshaveledto thedevelopmentand the naming of many cultivars for each of thefollowing genera: Leptospermum (Humm 1937;Lammerts1945; Powell1974; Edwards 1989a); Hebe(MetcaIf1987;Chalk1988;Hobbs1990); Phormium(Mole 1968; Heenan 1991a); Coprosma (Brockie1973); Metrosideros (Redgrove 1983; Hutchinson1988; Edwards 1987a, 1989b, 1991); Sophora(Butcher & Bicknell 1986; Redgrove 1986); andPittosporum (Metcalf1987). "

Artificial hybridisation has also been used inscientific research programmes and covers a broad

spectrum ofgeneraincluding: Coprosma (Allan 1926,1929); Epilobium (Brockie 1966, 1970); Phormium(Allan & Zotov 1937); Agropyron (Connor 1956);and Cortaderia (Connor1983).

The horticultural significance of New Zealandnative plant cultivars has been recognised by theInternational Horticultural Congress which hasconfirmed the Royal New zealand Institute ofHorticulture (RNZIH) as the International CultivarRegistration Authority for the genera Coprosma,Hebe, Leptospermum, Phormium, and Pittosporum.In addition, the RNZIHis the National RegistrationAuthority for all cultivars of nativeplants. The firstcultivar checklist to be published was for Leptospermum (Metcalfet aI. 1963)whichlisted76names.At November 1991, a database on Leptospennumcultivars, held by P. B. Heenanlists 140 names, an84% increasein only 28 years.

Two recent checklists are Phormium (Heenan1991a)and Cordyline (Heenan 1991b) whichlist 190and 33 cultivar names respectively. A cultivarchecklist inpreparation forHebe listsover700names(Metcalf1991). Manyof thesecultivars areavailabletodayfromcommercial nurseries andgarden centres.A livingcollection established at theBotanyInstituteDSIR, Lincoln, New Zealand, includes almost 120Hebe and over 80 Phormium cultivars.

With the exception of Leptospermum (Lammerts1945), manycultivarsof Newzealand plantsnamedbeforec.1960wereselectedbecausetheywereeithera new formor weredeviantfromthe typicalspecies.

Harris & Heenan-Domestication of the New Zealand flora 265

They were not necessarily better garden plants.However, development of objective orientatedbreeding and selection programmes has resulted inthenamingof cultivarsthataresuperiorgardenplants.Figure 1 illustrates the number of cultivars that havebeen selected and bad their names published from1860 for three genera-Leptospermum, Coprosma,and Metrosideros. Of particular interest is thesignificant increase in numbers since c. 1960 whichhas come about as a result of specific selection andbreeding work. The exact total of named cultivars ofNew Zealand plants is unknown but they numbermany hundreds, a number much greater than thatwhichcouldbe impliedfrom Haase's (1990)commentthat "several horticultural varieties are alreadyavailable (Metcalf 1987)". Metealfs book on thecultivation of New Zealand trees and shrubs listsover 350 cultivars of ornamentalnative plants.

Theseexamplesconfirmthatthepotentialofnativeplants for ornamental horticulture has already beenextensively explored and developed by the nurseryindustry. This development has been due to threedistinct but related aspects of the industry. First,gardeners continually demand new and differentvarieties; second, the nursery industry historicallyhas selected and named any variant; and fmally, inrecent years the plant breeder has been hybridisingand selecting to specificobjectives and criteria.

The ornamental and aesthetic values and thecultivationrequirementsof New Zealandplants havebeen the subjects of much writing. This has been indirect response to the interest and keen enthusiasmwith which native plants are grown by both nativeplantspecialistsandhomegardeners. The publicationslisted below indicate the variety and diversity ofwriting. Significantgeneralearlyarticlesare thosebyPotts& Gray(1870),Baber(1872,1885),Hay(1872),Thomson (1901), and Travers (1911). Importantwritings on New Zealand plants cultivated outsideNew Zealand are by Boscawen (1923), Williams (c.1935),Wall (1929),Cockayne(1914),Cheek (1979),andWright (1983).Generalgardeningbooks byNewZealandhorticulturists,for New Zealand conditions,includeimportantchapterson thecultivationofnativeplants such as those by Tannock (1924), Young &Hay (1926),McPherson (1943),and Murphy (1907).Significant publications specifically devoted to thecultivationof native plants includeCockayne(1923),Jackson (1965), Metcalf (1972, 1987 2nd Ed.),Matthews (1979, 1987), Fisher et al. (1978), andChalk (1988). /

Haase (1990) states that New Zealand's alpineplants are also "further potential resources as

ornamentals". There have been several publicationson the cultivation of alpine and rock garden plantswhich have a specialist following. These includeThomson & Simpson (1936, 1938, 1940, 1942),Brockie (1945), Philipson & Hearn (1962), andCartman (1985).New Zealand ferns provide anotherspecialist interest and accounts by Fisher & Ward(1976), Fisher (1984), and Brownsey & SmithDodsworth (1989) provide information on theircollectionand cultivation.

Native grasses, particularly the tussock grasses,and sedges,havebecomea distinctivefeatureof NewZealand landscapeplantings. There appears to be nogeneralaccount of their use for this purpose. Herbert& Oliphant (1991) provide information on thecultivationof pingao (Desmoschoenus spiralis), theendemic monotypic golden sand sedge, which isvalued for its uses in traditional Maori weaving andsand dune rehabilitation.

In addition,the New ZealandmonthlymagazinesCommercial Horticulture and The New ZealandGardener regularly feature articles on native plantsby a wide variety of authors. These numerous andvaried writings indicate the high esteem and keeninterest people have in native plants. Consequentlythe use of native plants for ornamental horticultureoccurson a nationalscale and is not local as statedbyHaase (1990). The commercial production of nativeplants is a significant small industry supporting atleast 12specialistnurseriesscatteredthroughoutNewZealand and at least one in Britain. General plantwholesale nurseries also produce large numbers ofindigenous plants and these are retailed at virtuallyeverygardencentre.Nativeplantsare usedextensivelyfor landscaping by localauthorities, regionalcouncils,universities, hospitals, and schools,andare commonlygrown in home gardens. Frequently these areplantsof the selected cultivars specially chosen because oftheir contributionto the colour, form, and texture ofgarden layouts and landscapes.

Botanic Gardens in the cities of Auckland,Christchurch, Timaru, and Dunedin all havesignificant native plant collections. At Wellingtonthe Otari Open Air Native Plant Museum wasestablished to cultivate a comprehensive livingcollection of New Zealand plants (Cockayne 1932).The AucklandRegionalBotanicGardenhas a currentprogramme selecting, evaluating, and promotinggarden use of ornamental cultivars developed fromindigenousspecies.The gardensof Timaru,Dunedin,and Christchurch produce an Index Seminumexclusive to New Zealand native plants. Smallercentres such as Taupo, Invercargill, Oamaru, and


Blenheim. to name but four, also have significantcollections of indigenous plantings in their publicgardens.

Internationally, 2.5 million Hebe are grown aspotted plants in Denmark (Edwards 1990) andCoprosma is becoming established in the UnitedStates (Edwards 1987b). Hebe has been the recipientofintensive research to determine the flower initiationand development requirements when grown as apotted crop plant (Kristensen & Adriansen 1988) anda commercial production package has been developedfor Leptospermum as dwarf potted plants (Bicknell1985). The Laboratory for the Improvement ofOrnamental Trees and Shrubs, Angers, France hasalso recognised the value of New Zealand nativeplants and is assessing the ornamental potential of aselect range of species, hybrids, and cultivars(Decourtye et al. 1991). Particularly in temperatecoastal regions of the Northern Hemisphere, forexample the southern British Isles, the Mediterraneancoast of France, and the coastal parts of California,New Zealand plants are commonly used inlandscaping. Cabbage trees (Cordyline australis) andflaxes (Phormium tenax) are often very conspicuoussubjects in these landscape plantings.

Historically Britain has a strong interest in NewZealand plants as is evidenced by writings in theirgardening and horticultural publications and thenumber of horticulturists who visit New Zealand tostudy the flora. The establishment of the Hebe Societyin Britain was a first for a New Zealand genus. NewZealand plants are regularly awarded honours by theAwards Committee of the Royal Horticultural Society(Mathew 1981; HalliweUl981; Anon. 1987).

From the evidence presented it is apparent thatNew Zealand native plants have received considerableattention to develop their use as ornamental plants.Significant potential has already been realised bothhorticulturally and commercially and the resource isnot under-developed as implied by Haase (1990).However, despite the achievements to date there isstill much hybridising and selection that can be done(Metcalf 1987), particularly in continuing furtherscientiftc approaches to plant breeding and selection.

CONSERVATION STATUS OF THE NEWZEALAND FLORA; POTENTIAL THREATS

Haase (1990) correctly emphasises the threats thatcontinue to affect the New Zealand flora, and indicatessteps that Bave been taken to offset these. Wilson &Given (1989) provide descriptions of 97 of the 151

New zealand plants classifted as threatened. Of these9 are presumed extinct, 46 are endangered, and 96vulnerable. Conservation strategies are discussed inthe introduction under the headings ofdocumentationand monitoring, reservation, cultivation, and genebanks, legislation, and education.

Wilson & Given (1989) point out that use ofplants for economic purposes may eitherpose a threator be a positive factor in the conservation of plantspecies. Thus, if economically valuable they can beexploited in a non-sustainable way, as has been thecase for the New Zealand native timbers, or they canbe brought into cultivation and used in a sustainableway as has been the case with the use ofnative plantsas ornamentals. Wilson & Given (1989) emphasisethat the availability of plants through propagationundertaken as part of commercial horticulture maybe a powerful weapon in combatting illegal trade inendangered plants. However, although conservationof attractive and easy to grow plants can be favouredby this process, cultivation of less attractive plantsfrom specialised habitats requires special attention.

CONCLUSIONS

Haase (1990) concludes that the small number ofcultivated plants derived from the New Zealand nativeflora is due to the short period of human occupationof the country. He suggests this has not given enoughtime for the selective breeding and cultivation ofindigenous plants. We can not agree with thisconclusion, and believe it gives a misleadingperception of the economic potential of the NewZealand flora and what has been achieved in NewZealand towards the development of economic plantuses.

With respect to food plants, Partridge & Harris(1988) considered that there are two peculiar featuresof New Zealand's biogeographic past that haveprevented the development ofesculent plants suitablefor human consumption. The first feature, alreadymentioned, is the absence of an indigenous landmammalian fauna apart from threebats. The absenceof large mammals leads to the assumption that therewas little selection pressure in the direction of largeedible fruits.Most fleshy fruits ofNew Zealand speciesare small and are used as food by the many smallpasserine birds found in New Zealand.

The now largely extinct fauna of ratite birds,characterised by the giantMoa (Dinomis spp.), appearto have been predominantly grazers of leaves andshoots. The effect of this extinct avifauna on the

Harris & Heenan-Domestication of the New Zealandflora 267

evolutionof NewZealandplantshas beena matterofconsiderable debate in recentyears e.g., Atkinson&Greenwood (1989). This debate has particularlyfocusedon the adaptivesignificanceof thedivaricateshrub form which is characteristic of a significantlyhigh proportion of shrubs in the flora. Certainly thehistoricalrecordshowsthatmanyNewZealandplantspecies were poorly adapted to tolerate grazing byintroduced mammals, and this lack of grazingtolerancehas been an importantfactor in the seriousdeterioration of the indigenous tussock grasslands(Daly 1990). Despite the prime importance of thepastoral industry to the New Zealand economy, noNew Zealand grass or herb has found a place inintensive pastureproduction systemsasa sownforageplant (Langer 1990).

Thesecondfeature proposed byPartridge & Harris(1988) relates to the rarity of New Zealand plantswith edible vegetativeparts, especiallyundergroundstorage organs. This can be related to the generallymild,moistoceanicclimateofNewZealandin whichfew nativeplants showmarkedseasonaldiebackandconsequently have no need for substantial storageorgansfor theirsurvival. The fewnativeplantswhichdo have such storage organs e.g., Pteridiumesculentum, Cordyline australis, wereintensively usedby Maori even though they were difficult to harvestand required elaborate preparation to render thempalatable. Their inconvenience as a food source wasthe reason why Maori largelyabandonedtheiruse ascropplantsandreplacedthemwiththeesculentplantsintroduced byEuropeans. Itis importanttoemphasisethattwoof themostsignificantof theseintroductions,potato (Solanum tuberosum) and maize (Zea maysL.), had been introduced to Europe from SouthAmericaless than 300 yearsbefore theirintroductionto New Zealand. For maize it has been establishedthatMaori developedtheirown uniquevarieties andused the species in a distinctive way to produce atraditional fermented com product, kaanga wai(Rhodes & Eagles 1984; Asmundson et al. 1990).Recentlyan industryhas beenestablished to producekaangawai usingmodem fermentation techniques.

The shortperiodof New Zealandhistorysinceitssettlementby Europeanshas beenremarkable for therapidity in which plant producing potential of thecountry has been converted from one supporting anindigenous vegetation inhabited most distinctivelyby an indigenous avifauna, to one predominantlysupporting an introduced flora of economic plantsmany of which are esculentplants for direct humanconsumption or for feeding mammalian livestock.This change has been achieved through significant

changes to soil fertility, the adaptation to the NewZealandenvironmentof many importedagriculturalsystems,and thedevelopment of severalnewones.Anumber of the systems developed in New Zealandhavebeensubsequently exportedtootherpartsof theworlde.g., deer farming, kiwifruitproduction, Pinusradiata based forestry. Introduction of plantgermplasm, plant selection, and plant breedinghaveplayed an important part in the transformation ofNew Zealandland use (Wratt& Smith 1983).As hasbeen describedfor the use of New Zealandplantsasornamentals, wheretherehas beentangibleeconomicend uses identified for a New Zealand plant,considerable progress has been' made in realisingtheseuses.

We are in agreement with Haase (1990) that theNew Zealand flora includesmany plants which stillprovideopportunities for furtherinvestigation of theireconomic potential and their suitability fordomestication. Although Brookeret al.(1988) indicatemany potential uses, very few have received theinvestment to undertake the necessary research,development, and marketing required to establishdefinitively whether theywillprovideviableeconomicproducts. Recentworkundertakenby the NewZealandDepartmentof Scientificand IndustrialResearch hasincludeda systematicsurveyof thepharmacologicalactivity of native plant extracts (S. 1. Bloors pers.comm. 1991),and evaluationof the essentialoils oftheNewZealandtea trees,Leptospermum scopariumand Kunzea ericoides (A. Rich.)1.Thompson(N. G.Porter pers. comm, 1991). Both of these areas ofinvestigation have shown promising prospects forthe provisionof new economicproducts. However,they are immediately confronted by marketimpediments such as the intention of chemicalindustries to synthesise chemical analogues ofpharmacologically activecompoundsrather than usenatural products, and conservative standards oforganoleptic perceptionin international essentialoilmarkets.

To conclude,it is appropriate to reiteratethat thefeatures that most strikinglydistinguish the biota ofNew Zealandfromothersignificantlandareasof theworldare theabsenceof an indigenous landmammalfauna and the late arrival of man. This has beenlinked to the paucity of esculent plants suitable forhumanconsumption. However, thefloradoesincludespecies which provide excellent materials for thetextile, shelter, and craft requirements of humans,and others useful for health and recreational needs.However, it is aesthetic values, linked to theuniqueness that arises from the short-term influence

268 New ZealandJournal of Cropand Horticultural Science, 1992, Vol.20

of man. that give the New Zealandflora its greatestvalue.Theparks andreserves systemin NewZealandisnecessary fortheprotection of theseaesthetic values(Kelly1980). Thissystemhas an important economicrealisation through the recreational and tourismactivities it supports. It is through theirconservationin natural communities by long term support andfurther enhancement of the New Zealandparks andreserves system, and their increased use in gardenand landscape plantings, that New Zealand nativeplantswill have theirgreatesteconomic realisation.

ACKNOWLEDGMENTS

We are grateful to Dr P. Wardle, Dr M. J. Parsons, and MsSue Scheele for bringing to our attention informationincluded in the paper and to Drs T. R. Partridge and R. L.Bieleski for constructive comments on the paper.

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Domestication of the New Zealand flora—an alternative view