The 2001 Banks Memorial Lecture Graeme C. Platt

The place of kauri () in the Six-Stage Sequential Order of Forest Succession/Progression

The Banks Memorial Lecture was given by Graeme Platt at a meeting of the RNZIH held at the Rutherford Hotel, Nelson in November 2001.

At first glance a mixed-species, potential as a forest giant. The light demanding Stage Three kanuka closed-canopy rainforest gives the pathway to fully understanding how (Kunzea ericoides) woody colonising impression of being a totally the bush works, and species to establish in the midst of a disorganised scramble of plants and the location of the kauri (or any herb, damp shady Stage Six climax broad- trees. The word "jungle" evolved to shrub, tree or fern) becomes apparent leaved forest. Both of these tree communicate the apparent confusion when the rules are fully understood. species are constituents of the same that exists when describing these The circumstances that dictate the forest. The Six-Stage Sequential Order magnificent forests. Closed-canopy place of any particular plant in the of Forest Succession/Progression is rainforests are not lawless jungles bush are firmly held by the a response to the fact that each where trees, shrubs, ferns, herbs and environmental tolerances that any separate stage of forest development grasses grow wherever a seed particular plant or tree species has to changes the environment by its own chances to fall. A strong set of rules the collective and ever-changing existence, creating a different set of firmly dictates the place of each environmental conditions. The environmental conditions. With the species. All species are sequentially changes in the ecology are created exception of Stage Six, the juvenile relegated by the changing by the constant relegation of species seedlings from any particular stage in circumstances created by each in the Six-Stage Sequential Order of the sequence cannot establish and separate stage of the six, clearly Forest Succession/Progression. The survive in the conditions that their defined stages that dictate exactly very existence of a tree species respective mother trees created. when and where any particular modifies its own preferred habitat to New Zealand is one of the most species will be offered an opportunity such an extent that its own offspring remarkable, if not the most to establish and grow to maturity. The cannot establish and grow at the same remarkable, place on earth to observe hold any species has on its preferred location. For example, a dry seeded and study sequential forest ecology. location is both temporary and woody colonising tree species, Although the surviving floral tenuous, before it is ultimately requiring an open sunny location to inheritance that is New Zealand's relegated to a location of adversity by establish and grow at its preferred natural bush today is a highly modified species from subsequent stages in location, will, by its own existence, and hugely depleted Ice Age relict of the Six-Stage Sequential Order of create a dense shady place where its a once rich Gondwana-base, it is a Forest Succession/Progression. own offspring don't stand a chance. unique microcosm of the global The location of kauri (Agathis The shady space under the tree will floristic picture. The latitudinal position australis) - or the specific ecology of then be occupied by a wet-seeded, of New Zealand, located half-way any particular plant or tree species in shade-tolerant species from between the Equator and the Pole, the New Zealand bush - is dictated subsequent stages that are dependent has allowed remnants from both the by the total dynamics of the entire on damp shade to establish and grow ancient Paleozoic and Mesozoic and ecology of the bush, that is best seen to maturity. As the light-demanding their modifications to survive as a single living organism. The Stage Three woody coloniser trees regardless of the deprivations of the location of any particular species in succumb naturally to old age, they Cainozoic Ice Ages. The New Zealand the bush at any particular time is are replaced with shade-tolerant flora constitutes a uniquely balanced dictated by the combined influence species from the subsequent Stage ecology that is very rare elsewhere. of all the other constituent species. It Four in the sequence. Also, the New Zealand bush has a is not possible for a simple grass to It is all but impossible for a wet- reasonably balanced number of establish randomly in the bush, any seeded Stage Five softwood kauri effective species in each of the more than it is possible for, say, a tree to germinate and establish out in separate stages, therefore the ecology mighty kauri tree to establish and grow an open Stage Two dry grassy field, is not dominated by any single stage. out in a grassy field and reach its just as it's equally impossible for a Furthermore, the diverse geophysical

PG 12 The 2001 Banks Memorial Lecture features of New Zealand's "fussy" landscape create many small microclimates where all six stages can often be observed at a single location, without having to travel thousands of kilometres to see each stage in its pure form. The purity of each stage is often very clearly defined, to such an extent that at times it may be seen with clear demarcation lines drawn across the countryside between the separate stages. Every tree, shrub, fern, and herb in the New Zealand flora can be allocated a proper place into one of the separate stages. To qualify for a place in a particular stage, all species have certain physiological and climatic tolerances in common, e.g. the grasses and herbs of Stage Two are all highly light-dependent plants of the Cainozoic era, which are tolerant to extremes of heat, wind and sunlight, and have dry seeds. The physiological tolerances of all plants to the parameters of climatic adversities are a direct correlation to the climatic conditions that existed on earth at the time of their basic evolution. Trees and plants of any particular stage are only able to germinate and establish when the conditions collectively created by the total mass of plants in that particular stage are equal to the conditions that existed on earth at the time of the plants basic evolutionary development. The exact stage of development any particular patch of bush has attained is ascertained by the numerical dominance of the listed The majestic kauri indicator species representative for that stage. As the process is a eventually succeeding it. When streamsides and shady cliffs etc. sequential transition, where plants any genus has more than one The New Zealand bush sequences and trees from one stage are relegated variation, each variation is a separate through six separate Stages before by the plants from a subsequent adaptation to a different set of terminating as Stage Six broad-leaved stage, species from two separate ecological circumstances. No two climax forest. However, each separate stages will be mixed during the variations within a genus are equal, Stage may terminate and become transitional period from one stage to and each variation occupies a climax at locations of adversity. For another. separate location in the environment. example, where conditions are so Stage Three woody colonising For example, Phormium tenax is a adverse, Stage One will remain species in the Sequence move over light-demanding variation of permanently free of plants, creating the top of the preceding Stage Two Phormium growing out in open sunny a desert. While New Zealand doesn't grasses and herbs. All subsequent locations, while Phormium have any great deserts, there are many stages move in under the shady cookianum is more shade-tolerant, small locations of adversity where canopy of the preceding Stages with a habitat in shady locations along plants are denied a change, such as

The 2001 Banks Memorial Lecture PG 13 in the high mountain nival zone, where mountains and the wet areas of the into locations of adversity by the permanent ice and snow create Southern Alps are significant subsequent stages. The Stage Six conditions so hostile plants cannot examples of climax Stage Three broad-leaved climax forest trees are survive. Mobile sand dunes, solid woody coloniser forests. Another the only species that are able grow rock, vertical cliff faces and the littoral example is the Southern rata forest on in perpetuity at locations of salt sea spray zone are all locations (Metrosideros umbellata) on Campbell luxuriation, while all of the other tree of adversity, often devoid of plants. Island in the Sub-Antarctic Island and plant species in the preceding Mineral toxicity, as a result of volcanic group. These forests are protected stages are relegated to sites of action, creates some of the larger from progression by the adversity of adversity. The reality is that all plants permanent Stage One sites of bare their location, as are terminal woody growing to maturity in New Zealand ground where plant life cannot coloniser forests. Nothofagus are wet- native bush have been relegated into establish and grow to maturity. seeded Mesozoic species that occupy hostile sites of adversity by the Stage Stage Two Herbaceous Colonisers a place as Stage Three woody Six climax broad-leaved hardwood terminate as climax tussock colonisers. New Zealand's highly forest species, which are honoured grassland, where and when conditions modified Cainozoic variations of the with the privilege of a permanent are so adverse that Stage Three wet-seeded Mesozoic southern habitat in a location of luxuriation. woody colonisers cannot establish beeches survive today as great Stage (The early settler farmers of Northland and grow. The magnificent Stage Two Three forests because they have wet understood this with the saying, tussock grasslands on the eastern seeds, and are capable of surviving "Never purchase land unless it is side of the Southern Alps are in cold wet locations where there is covered with puriri, (Vitex lucens), dominant because the environment no effective competition. Where the karaka (Corynocarpus laevigatus) and is so adverse that Stage Three woody site is drier, the dry-seeded Cainozoic taraire (Beilschmiedia taraire) trees". colonisers are denied a chance to tea trees kanuka and manuka These trees are Stage Six climax move in and sequentially replace dominate as the Stage Three woody broad-leaved species. The farmers them. This situation is the reality with colonisers. The magnificent Stage observed that Stage Six tree species all separate stages of the sequence. Three woody coloniser forest of only occupy the good land. All other Stage Three woody coloniser species pohutukawa (Metrosideros excelsa) species have only one chance to will terminate as climax forest where on Auckland's Rangitoto Island is not occupy their preferred location of conditions are so adverse that they a climax forest. The pohutukawa trees luxuriation, before they are relegated cannot be superseded by Stage Four are being sequentially replaced with out into a location of adversity by the primary broad-leaved forest, and so other species in the correct order, due species from subsequent stages in on through the sequence. to Rangitoto Island being a site of the sequence. The superb Southern Beech luxuriation. In a few hundred years The Stage Four primary broad- (Nothofagus) forests in the cooler from now, pohutukawa trees on leaved tree species may be observed Rangitoto Island will only occupy the in their purest state under the canopy coastal fringe, as they do elsewhere. of exotic plantations of radiata pine Each stage in the sequence of and eucalypts. When these exotic Forest Succession/Progression has plantations are nearing maturity at two separate states: a state of about fifty years and are correctly luxuriation and a state of adversity. spaced, it is extremely difficult for any As with the Chinese academic other species to grow under them concept of Yin-Yang, the continuum except the wet-seeded Mesozoic joining the two states is a graduated species from Stage Four of the scale of ever-increasing divergence. sequence. Not only is shade essential At one end of the scale a specific for the survival of the Mesozoic plant will grow to perfection, but as it species of Stage Four, the moist nears the other end there is a point organic litter on the forest floor is where its survival becomes essential to create the conditions for impossible. Species from all stages their wet seeds to remain viable and (except Stage Six) are confronted with germinate. severe competition in locations of The shade-dependent Paleozoic luxuriation. Consequently, they are ferns, especially the tree ferns, relegated into locations of adversity colonise and establish in the shady near the very brink of survival. conditions within Stage Four Primary The more luxuriant a particular broad-leaved forest. While tree ferns location is, the quicker the species remain a highly visual feature within manuka contained within it are relegated out the latter Stage Five and Stage Six

PG 14 The 2001 Banks Memorial Lecture forest types, they decline significantly, relegated into shady locations in the numerically as the forest progresses Cainozoic. through to Stages Five and Six. The major exception to the rules The epiphytes that perch high are the many tangled, wiry, divaricating amongst the branches of mature variations of shrubs that exist within Stage Five softwoods and the Stage the New Zealand flora. This Six broad-leaved climax forest trees, phenomenon of tangled growth is one are, in reality, mostly species from of the most interesting evolutionary Stages Three and Four taking adaptations known in botanical advantage of the appropriate space science. Sadly, it has been pathetically created on the old trees. The mature trivialised for many years by claims Stages Five and Six trees have, in that the giant - and now extinct - matai fact, created the correct "terrestrial" flightless Moa created these variations sites for the species from the earlier by constantly picking leaves off them. divaricating juvenile form with small stages high amongst their branches. All of the tangled, divaricating plants leaves, that reverts to its larger adult Northern rata (Metrosideros robusta) are modern adaptations of ancient foliage after the tree has attained a is a Stage Three woody coloniser. Mesozoic Stage Four wet seeded height of about two metres, allowing Puka (Griselinia lucida) is a Stage Four genera, trying to move forward and it a move forward into Stage Four. On primary broad-leaved species, as is adapt into the modern dry seeded the other hand, Sophora prostrata is Pittosporum cornifolium. The blade- Cainozoic Stage Three ecology. a dry seeded Stage Three woody leaved monocotyledons, such as Furthermore, a number of tree genera colonising shrub, rarely reaching three Collospermum hastatum and Astelia have variations that also have a metres in height, that remains a solandri, which festoon the mature tangled, wiry, juvenile stage, allowing permanent constituent of Stage Three. Stages Five and Six trees as them to temporarily occupy a place Each tree genus that has a variation epiphytes, are wet-seeded, shade- in the modern adverse Cainozoic with a tangled divaricating juvenile dependent Mesozoic plants fighting Stage Three ecology. However, when growth and small foliage also has a for their correct place in Stage Four. the forest has progressed to Stage non-divaricating opposite: matai Prior to the evolutionary development Four, the foliage of these trees revert (Prumnopitys taxifolia) and miro of the sun-tolerant plants of the back into their true and proper adult (Prumnopitys ferruginea); pokaka Cainozoic, these shade-dependent form, to occupy their correct place (Elaeocarpus hookerianus) and hinau plants of the Mesozoic would have within the sequence. This (Elaeocarpus dentatus); Plagianthus occupied open locations in much the phenomenon is an evolutionary issue divaricatus and Plagianthus regius; same way as primary herbaceous of the greatest interest. These modern Streblus heterophyllus and Streblus colonisers do today. Cainozoic adaptations are actually banksii; Pennantia corymbosa and There may appear to be exceptions jumping back and forth across the Pennantia baylisiana, etc. The large- to the rules: parataniwha (Elatostema Mesozoic-Cretaceous/Tertiary- leaved variants of every genus are the rugosum) is a herb that occupies very Cainozoic evolutionary boundary line. Mesozoic evolutionary base, while the shady wet, places in Stage Six broad- They commence life out in the open tangled, wire-like divaricating leaved climax forests. However, this as small leaved Stage Three Woody variations with small leaves are the herb is very shade-tolerant and follows Colonisers and revert to their correct modern Cainozoic adaptations. With all the rules. Parataniwha is a large leaved Stage Four Primary the shrubs Corokia buddleioides is Mesozoic herb with wet seeds, and Broad-leaved form when the bush the Mesozoic variation occupying its cannot occupy a place alongside the collectively reaches Stage Four. correct place within Stage Four, and modern Cainozoic sun-tolerant, dry The juvenile leaves on New Corokia cotoneaster is the Cainozoic seeded herbs and grasses of Stage Zealand Stage Six trees are larger adaptation struggling to occupy a Two. Orchids are wet seeded than the mature adult leaves, in place in Stage Three. Coprosma Mesozoic herbs that probably occupy accordance with the global norm. grandifolia is the shade-dependent just about every shady ecology However, the juvenile leaves on many Mesozoic variation, and Coprosma known. A number of wet-seeded, of New Zealand's wet seeded Stage acerosa is one of the many modern blade-leaved herbaceous Four are smaller than the mature adult sun and cold wind-tolerant Cainozoic monocotyledons of the Mesozoic are leaves, due to the Cainozoic enforced adaptations of coprosma. also included in this group: Xeronema, adaptations of these Mesozoic The off-shore islands, particularly Collospermum and Astelia. While species. the northern groups of the Poor these ancient herbs may appear to Kowhai (Sophora microphylla) is a Knights, Three Kings, and Hen and be violating all of the Sequential Order dry seeded tree species that correctly Chickens, are the refuges for the of Succession/Progression rules, they establishes out as a dry seeded oldest and least modified variations are wet seeded Mesozoic herbs woody coloniser with a very tangled of the flora. The large-leaved Mesozoic

The 2001 Banks Memorial Lecture PG 15 species from Stages Four, Five and correct sequence. If the hole in the of the South Island are dominated by Six that exist on the islands, with their Stage Six climax bush is very relatively Cainozoic Stage Two herbs and relatively stable maritime climates, small, it may be filled with tree species grasses. The beech forests, covering have been least affected by the from Stage Six, bypassing all the the cooler, wetter parts of the South adversities of the Cainozoic, such as preceding Stages. Island and the lower North Island, the privations of recurring Ice Ages The importance of the Six Stage represent Stage Three primary woody and periods of dryness. The variations Sequential Order of Forest colonisers. The lower North Island is of each genus with smallest leaves Succession/Progression in ecological dominated by species from both are generally located in the southern, studies cannot be over-emphasised. Stage Four primary broad-leaved cold, frosty, exposed wind swept Not only is the Six-Stage Sequence forest and Stage Five softwood forest Mountain valleys and hillsides. the order of forest development at trees. The upper North Island through The Six-Stage Sequential Order of any specific location, it is also the to the equator is dominated by the Forest Succession/Progression altitudinal sequence from the top of Mesozoic Stage Six climax broad- cannot be reversed, except by a mountain to its lowland base. All six leaved species. While the demarcation destructive force - such as stages of the sequence may, at times, lines between the various stages experienced as the result of a bush be clearly visible as separate altitudinal through the length of New Zealand fire or a windstorm, sending trees strata across the sides of high are rather vague and often crudely crashing to the ground. Any holes mountains: Stage One is the snowy, defined, the dominance of Antarctica created in the forest are reoccupied ice-capped nival zone permanently (as representing Stage One with no again, with plants and trees in the devoid of plants; Stage Two plants), and the hot closed canopy correct order as per the Six-Stage herbaceous colonisers occupy the rainforest at the equator (representing Sequence. While it is impossible for zone between the snow-cap and the Stage Six climax broad-leaved the Six-Stage Sequence to be tree-line, where the shrubs and woody hardwoods forest species of the reversed, stages may be, and often colonising trees of Stage Three are Mesozoic), is more than clearly are, skipped over completely. Stages fighting their way up the mountainside; evident. are only skipped over and missed out Stage Four primary broad-leaved The continuous landmass of South at locations of luxuriation. This often species occupy the lower slopes, America running from the Equator to happens in Northland, where Stage clearly indicated with their dense edge of Antarctica is the prime One bare ground is colonised directly green foliage and by the presence of location to observe this situation. by Stage Three woody colonisers, a multitude of tree ferns; Stage Five Amazonia in equatorial Brazil is such as manuka and kanuka, Stage softwoods occupy the warmer lower dominated by Stage Six Climax Two herbaceous colonisers being ridges; and Stage Six climax broad- Broad-leaved tree species. Parana completely bypassed. This situation leaved forest tree species are and Santa Catarina states located only takes place at locations where dominant in the sheltered, fertile slightly south of the equatorial region conditions are perfect for direct valleys at the lowland base of the is the home of the Stage Five occupation by the appropriate stage. mountains. Softwood Araucaria angustifolia and In the mountains, snow, ice and rock The relegation of all species into the podocarps with an under story of avalanches crashing down the locations at the very limit of their Stage Four Primary Broad-leaved mountainsides into the bush can leave physiological tolerances, within the species. Stage Three dry seeded a path of destruction that is so fertile development of any single patch of woody colonising trees and shrubs and sheltered by the trees in the bush bush, is also repeated latitudinally. dominate the open sunlit flora of on each side that it is occupied by The six stages in the sequence also Northern Argentina. Patagonia in Stage Four primary broad-leaved run in a graduated line from the South Southern Argentina is dominated by species, completely missing out both Pole to the Equator, marked with a massive Stage Two primary Stages Two and Three. Holes in the dominance of plants from each Stage herbaceous grasslands and Antarctica bush, created by senile old trees falling at separate latitudes. Antarctica can represents Stage One land bare of over or wind damage in Stage Six be seen to represent Stage One vegetation. broad-leaved climax forest, are always devoid of any plants. The Sub- replaced by plants and trees in the Antarctic Islands and the drier parts

PG 16 The 2001 Banks Memorial Lecture The Six-Stage Sequential Order of Forest Succession/Progression Each Stage is listed with the predominant indicator species representative of that Stage.

STAGE ONE: Bare Ground Bare Stage One ground is land that is free of vegetation after a destructive event, such as a bush fire, volcanic eruption, mobile sand invasion, landslip, silt inundation etc. Any location that is free of vegetation for whatever reason. While Stage One has no visible plants, land in this state is occupied with an innumerable assortment of micro-flora and fauna in the form of bacteria, yeasts, fungi and lichens.

STAGE TWO: Primary Herbaceous Colonisation (Grassland) Stage Two plants are light-dependent, all are very tolerant to the extremes of sunlight, wind, dryness, and cold, and all evolved and developed in the modern Cainozoic era. All species have dry seeds, with extended periods of viability lasting at times for many years.

Carex Cortaderia Cyperus Festuca Acaena Scirpus Aciphylla Chionochloa Spinifex Danthonia Linum Raoulia Celmisia Haloragis Juncus Gahnia

STAGE THREE: Woody Colonisers All trees and shrubs evolved and developed in the Cainozoic era, all are light-demanding angiosperms with dry seeds that at times remain viable for many years. New Zealand's Nothofagus are highly modified Cainozoic variations of a wet seeded Mesozoic genus, occupying cold wet sites as a Stage Three woody coloniser.

Leptospermum Hebe Carmichaelia Kunzea Sophora Pomaderris Metrosideros Brachyglottis Pachystegia Dracophyllum Cassinia Weinmannia Epacris Dodonaea Olearia Nothofagus

STAGE FOUR: Primary Broad-leaved Forest All Stage Four trees, shrubs and ferns are shade tolerant. Many are extremely intolerant of bright sunlight, all the ferns have their origins in the Paleozoic and the broad-leaved species of the Mesozoic era. They all have wet seeds contained within juicy fruit, drupes and berries (or are ferns with spores). Wet seeds have a very short period of viability, lasting from between two weeks to three months, and must germinate and establish within one season. Fern spores cannot germinate in direct short-wave light, and are dependent on total shade and moisture to reproduce, establish and grow to maturity.

Fuchsia Melicytus Cyathodes Pseudopanax Aristotelia Schefflera Pittosporum Elaeocarpus Myrsine Coprosma Dicksonia Myoporum Hoheria Cyathea Geniostoma Griselinia Corokia Nestegis

The 2001 Banks Memorial Lecture PG 17 STAGE FIVE: Softwood Forest Stage Five softwood trees are all Gymnosperms of the Podocarpaceae, , or Cupressaceae, originating in the early Mesozoic, and producing either wet-seeded fruit, or cone-bearing softwood trees with wet seeds. While seeds of Agathis, Podocarpus and Libocedrus may superficially appear to produce dry seeds, they are wet, with a very short, one-season period of viability.

Agathis Lepidothamnus Dacrycarpus Podocarpus Libocedrus Prumnopitys Halocarpus Phyllocladus Lagarostrobos Dacrydium

STAGE SIX: Climax Broad-leaved Forest The trees of Stage Six are all broad-leaved hardwood angiosperms with wet seeds produced in large juicy fruit, except Laurelia with its windborne seeds, which must fall on very wet ground and germinate within two or three weeks to survive and germinate as new seedlings. The broad-leaved Angiosperms, trees from Stage Six, evolved during the Cretaceous period of the Late Mesozoic. The Arecaceae is represented in Stage Six by Rhopalostylis. Tree species from Stage Six have an extremely shade-tolerant juvenile stage of growth.

Hedycarya Dysoxylum Litsea Syzygium Rhopalostylis Pouteria Beilschmiedia Vitex Laurelia Corynocarpus Alectryon

The place of kauri Kauri often achieves numerical The predominant location of the As shown above, kauri is a Stage Five dominance on ridges, creating an bulk of the twenty recognised softwood forest species, with a illusion that ridges are its preferred variations of Agathis at the at the edge preferred natural habitat in rich, moist, habitat. of the wet tropics, otherwise on lowland valley floors where it attains The three largest surviving kauri mountainsides or high ridges within a massive size. However, it is relegated trees in New Zealand each have a the tropics coincides perfectly with to poorer soils on exposed ridges and theoretical timber capacity of over their place as a Stage Five softwood hillsides. Kauri trees are sequentially two hundred cubic metres. These are species in the Six-Stage Sequential replaced out of their preferred habitat Tane Mahuta with 244.5 cubic metres, Order of Forest by the more shade-tolerant juvenile Te Matua Ngahere with 208.1 cubic Succession/Progression. The plants from Stage Six climax broad- metres, and the Phantom Tree with equatorial forests are occupied by the leaved forest trees. Additional approximately 208 cubic metres. late Mesozoic Stage Six tropical evidence that New Zealand's Stage These giant trees, located in the broad-leaved hardwood tree species, Five kauri trees are relegated into , are all growing in relegating the Stage Five softwood locations of adversity by Stage Six very wet ground surrounding a great slightly south or higher up climax broad-leaved species is swamp. This situation is clearly visible the cooler mountainsides. precisely recorded in the annual from the air, if not from the ground. Many conservation and forest growth rings of trees growing in the The large number of huge, deep- management strategies are very two respective locations. Kauri trees reaching peg roots that support these seriously flawed, as they are all based growing in their preferred location of trees, penetrate to a depth of three on the false assumption that the luxuriation in rich, moist, valley floors to four metres under the tree into the natural habitat of a particular species may at times have between one and water-table, maintaining moisture is its preferred habitat. The reality is five annual growth rings to the stability within the trees. While large that all plants are marginalised into centimetre. Kauri trees forced out into kauri trees at times grow high up on sites of adversity by species in the locations of adversity may have as hillsides, these large trees are always subsequent stages in the Six-Stage many as twenty-five or thirty-five located in wetter locations in gullies Sequential Order of Forest growth rings to the centimetre. Trees or beside watercourses, where the Succession/Progression. The concept growing in warm valleys with rich, natural rainfall is concentrated beyond of selectively logging Stage Five moist soils can grow up to ten times the natural precipitation by being softwood timber tree species faster than those on exposed ridges. funnelled into the root range of trees. (including kauri) on a sustainable yield

PG 18 The 2001 Banks Memorial Lecture basis is a very seriously flawed Succession/Progression. New The time-scale of the Six Stages, concept, as the damage caused by Zealand kauri is relegated out of its based on the warm northern kauri the felling of kauri trees reverts the preferred natural habitat in the warm, forest sequence, climaxing as Stage bush back to Stage One, where the moist, valley floors by the Stage Six Six, with taraire, puriri, karaka, and Six-Stage Sequence commences broad-leaved hardwood climax tree kohekohe being the dominant broad- afresh. Any clearings created in the species. leaved tree species. bush where kauri is felled will be Kauri is a shade-tolerant species colonised by Stage Two herbaceous during its juvenile phase. However, Stage One colonisers and Stage Three woody optimum growth potential is only Bare ground colonisers, such as manuka and realised when the correct spacing has kanuka, and not Stage Five softwood been won by the young adolescent Stage Two After a fire, bare ground will be species such as kauri. trees, gaining access to high light. carpeted with herbs and Only Stage Three woody colonising Agathis australis has a tall erect apical grasses for1-3 years trees and shrubs can be harvested in growing shade tolerant juvenile form, perpetuity on a sustainable yield basis, a direct inheritance from having its Stage Three and only at locations of luxuriation roots in the Mesozoic and a bushier Woody colonisers establish 1- (and using the correct tree-felling disordered crown in response to the 10 years after a fire, and have regimes that retain mature seed trees variable conditions of the modern generally eliminated all herbs in adequate quantities to allow for the Cainozoic Four Season Solar ecology. and grasses within 15 years. proper dispersal of seed). The bush Due to its genetic inheritance The life span of average Stage Three kanuka in the Auckland clearings where Stage Three woody forced on it during the Cainozoic Ice and lower Northland is colonisers have been felled will be Ages, New Zealand kauri is capable approximately 60-120 years recolonised by their own kind from of growing in cooler conditions than within Stage Three. The Stage Three those experienced in its natural habitat Stage Four species manuka and kanuka can be of today. Kauri, under conditions of Stage Four species commence harvested as bakery-grade fuel-wood cultivation, are performing establishing 12-15 years after and source of essential oils, and considerably better further south in the Stage Three woody several Nothofagus as sources of Taranaki than it does in its natural colonisers first establish. As the saw-wood, wood products and wood habitat of northern New Zealand. Stage Four species progress fibre. While the Agathis australis gene concurrently with Stages Three The continuous relegation of pool was decimated as a result of and into Five, they have a major species into locations of adversity at over one hundred years of reckless influence on the length of time the extreme limits of their ability to and uncontrolled logging practices for forest progression survive in the conditions created by from the mid 19th to the mid 20th Stage Five the natural Six-Stage Sequential Order century, quality gene stock is available The life span of average large, of Forest Succession/Progression, is over a very wide area of the original 2 m diameter kauri is 450 - 750 the prime cause of so many species habitat in many actively regenerating, years. At a location of being catalogued as "endangered small, scattered groves. New Zealand luxuriation, softwoods are species". Translocating "endangered kauri today is actively recolonising generally establishing well, 50- species" to their preferred location of the bush in a fully functioning natural 80 years after the Stage Three luxuriation, into the correct stage of ecology, occupying its correct place woody colonisers have the Six-Stage Sequential Order of in the Six-Stage Sequential Order of established Forest Succession/ Progression, is Forest Succession/ Progression. The Stage Six the only practical way to ensure their future of New Zealand kauri is secure Climax broad-leaved forest is survival. Species are forced towards without great acts of active human the only forest type able to extinction because they have been intervention. However, it is vital that regenerate in perpetuity at a relegated to a location of adversity these areas of naturally regenerating location of luxuriation. Stage where their survival is often difficult, kauri be left to grow in peace, with Six forest is fully established if not impossible. total protection for all time. when all of the softwoods have Kauri is a long-lived tree species Future conservation policy of all completed their life cycle and maturing as a very large tree, with a naturally occurring tree species should have been replaced by natural habitat in New Zealand forests be based on the concept that "if it hardwoods (calculated as 810 north of 37 degrees south. Kauri is a wasn't planted by man, then it should years) Stage Five tree species in the Six- not be harvested by man". Stage Sequential Order of Forest

The 2001 Banks Memorial Lecture PG 19