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AUSTRALIAN FORESTERS in PAPUA NEW GUINEA 1900-1975

PNGAF MAGAZINE ISSUE # 9B - 3 of 29th March 2021 STRUCTURE OF RAINFOREST 1

Editor R B McCarthy2 2021

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Vanimo Rainforest. Photo credit Ian Whyte 1974. District Forester TPNG 1963-1975

TABLE OF CONTENTS “FORWOOD”

page 3

The Structure of Rainforest Trees in the Rainforest Richness of Rainforest Floristic Origin Composition of Rainforest Stands Forest Structural Formations

page 5 page 10 page 13 page 14 page 14 page 15

New Guinea Forests – Structure, Composition, & Management (Havel) Nature of Study Major Trends in Forest Types of PNG Moisture Gradient in the Lowlands Very Wet Sites Sites with Optimal Moisture Regimes Topographically Dry Sites Climatically Dry Sites Altitudinal Temperature Gradient Lower Altitudes Middle Altitudes Upper Altitudes

page 16 page 16 page 16 page 18 page 18 page 21 page 24 page 26 page 30 page 30 page 34 page 36

CSIRO Contribution to PNG’s Botanical Knowledge (Granger)

page 37

Forest Resources and Vegetation Mapping (Hammermaster & Saunders)

page 37

The Silvicultural Significance of Floristic Composition

page 39

Relation of Rainforest to other Vegetation Types. Riverine Associations Swamps

page 39 page 40 page 42

Bibliography

page 47

Acronyms

page 48

“FORWOOD” Rainforest is a most complex form of vegetation. Although, there are significant differences both between and within the rainforest formations, the wealth of species and the richness and variety of the life forms set rainforest apart from all other plant communities. The growth in rainforest is primarily woody. One of the outstanding features of rainforest is the dominance of tall, woody plants. The plant formation consists not only of trees but also shrubs, stranglers, woody vines, epiphytes, herbs, and other less conspicuous life forms. Most rainforest stands appear to support approximately 1000 trees per hectare larger than 50 cm diameter breast height. Among the tallest rainforest trees are the Araucaria spp (hoop and klinkii pine) found in PNG and eastern Australia. Some of the widest diameter trees are Ficus spp and Agathis spp. The most striking features of many rainforest trees, particularly in the tropics are the growth developments of the lower stem – the buttresses and the stilt roots. The richness of the flora appears to vary through two causes. One depending upon the wealth of the regional flora and the other upon the suitability of the site for the trees from this flora to grow. The origins of rainforest flora are recognized as probably coming from two sources, one of pan tropic origin and the other of southern or Antarctic origin. In general, the PNG vegetation classification is based on the structural formation of the vegetation. Six structural formations are recognized – forest, woodland, savanna, scrub, grassland, and mangrove communities. Havel3 published a detailed study4 in 1972 detailing the usefulness of forest typology to forest management in PNG. The purpose of this study was to point out the relevance of ecological studies to the management of the very varied forests of PNG. The forest types of PNG are arranged along two gradients; the moisture gradient in the lowlands and the temperature gradient in the Highlands. In the lowland moisture gradient, Havel described the lowland rainforest as the most complex type both structurally and floristically. Lowland rainforest is characterized by development of three tree strata, abundance of climbers and epiphytes and the prevalence of evergreen mesophyll species of many genera and families. With departure towards the wet or dry end of the moisture gradient, the result is a reduction in both floristic and structural complexity. The altitudinal gradient from sea level to the summit of Mt. Wilhelm (4500m) is rather complex as described by Havel. It incorporates not only marked changes in temperature, but also in insolation, humidity, and exposure. The rate of change is not uniform. The proportion of marketable species is high in all segments of the altitudinal gradient up to 3000 m. The chief limitation is access. In the Highland valleys, Havel reported that anthropogenic grasslands occupying former forest sites, were now being planted by the Dept. of Forests extension programs, with exotics 3

Joe Havel TPNG Forests1953-1965 including Inaugural Principal Bulolo Forestry College 1962-1964 J. J. HAVEL (1972) New Guinea Forests—Structure, Composition and Management, Australian Forestry, 36:1, 24-37, DOI: 10.1080/00049158.1972.10675567. 4

better able to cope with impoverished soils and grass competition, rather than the indigenous araucarias. In PNGAF Magazine Issue # 7 of the 11th of January 2021, Ken Granger5 described the contribution of CSIRO to PNG’s forest resource and botanical knowledge 1953-1969. The resulting reconnaissance-level regional survey reports and maps provided extensive baseline information for national development planning. PNGAF Magazine Issue # 8 page 42-43 described the forest resources and vegetation mapping project of PNG by Hammermaster6 and Saunders. It reflects the progress made in mapping PNG vegetation since the 1970’s with the advent of the computer era and associated digitisation. Different communities are apt to respond in different ways to a particular silvicultural technique and, by appreciating the differences in composition of rainforest within any area, adequate treatments can be applied to each with a greater likelihood of success. Rainforest does not exist in isolated condition. Often the junction between rainforest and its neighbour is a merging one that cannot be precisely defined. The vegetation types replacing or adjoining rainforest in sites subject to frequent inundation or constant sea-wind exposure are clearly the most complex. An understanding of their ecology is essential not only to forest management but to many aspects of sound land use. But perhaps to both ecologists and foresters, the most important point is that the effect of fire alone, probably determines a greater length of inland rainforest boundary than by all other factors together. Where suitable species are available to take advantage of this fire effect, as with Pinus and Eucalyptus, the resultant fire induced stands may be of great forestry importance. Here, the ecological similarity between Pinus and Eucalyptus is of interest to the forester as these two genera are those widely used in deliberate schemes throughout the world to convert sites capable of supporting rainforest to pure stands.

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Ken Granger TPNG Forests Technical Officer to Management Officer 1963 to 1970. Eric Hammermaster TPNG Forests Cadet Forester to Divisional Forester 1956-1979

THE STRUCTURE OF RAINFOREST By any standard, rainforest is a most complex form of vegetation. Although, there are significant differences both between and within the rainforest formations, the wealth of species and the richness and variety of the life forms set rainforest apart from all other plant communities. The growth in rainforest is primarily woody, and one of the outstanding features of rainforest is the dominance of tall, woody plants. The plant formation consists not only of trees but also shrubs, stranglers, woody vines, epiphytes, herbs, and other less conspicuous life forms. Shrubs are probably the most obvious group of rainforest plants, since they are the plants with which anyone working in the rainforest is almost constantly in contact. Where the shrubs have irritant properties, stinging hairs, thorns, or spines, or are myrmecophilous, this contact can not only be unpleasant, but can also influence silvicultural practices e.g., reluctance to eradicate stinging plants. One or two distinct shrub layers can usually be recognized in rainforest. These layers contain not only small individuals of taller trees, but also numerous species, which are restricted to shrub size. The small trees very characteristically have a single, unbranched stem, surmounted by a tuft of leaves, but this habit is also shown by many of the true shrubs. Besides the single-stemmed shrubs, rainforest usually also contains many heavily branched shrubs which cast dense shade. When present in any quantity, these exert a strong effect on the microclimate near the ground, and, like the wider spreading, low palms, can make difficult, the establishment of regeneration. The shrub layer also often contains some plants, which are large herbs. These are mostly monocotyledonous plants, and on various occasions, they may form thickets sufficiently dense to deter regeneration and to require special attention in silvicultural treatment. Plants such as these are a feature of the more open rainforest phases e.g., in southern Nigeria, and probably provide elephants with some of their preferred foods; so that the dominance of the monocots and the existence of the open patches both tend to be long lasting. Bamboos also may be present in the shrub layers of rainforest, and these too may require special silvicultural treatment. Ground herbs are usually present in rainforest, but as scattered plants rather than a continuous ground layer. Only where the overhead canopy is sparse do the herbs tend to become abundant. Ferns are the most common. By contrast, the rainforest climbers have very great silvicultural significance and probably constitute the worst of all groups of rainforest weeds. These form a distinct life form, through species suggesting a connecting stage with trees. They range from rather small, wiry vines restricted to the undergrowth to large vines which reach to the treetops and which may have stems as thick as a small tree. As a group, the climbers are strongly light demanding and for this reason tend to be most frequent in rainforest gaps or where the canopy has opened during silvicultural treatment. The climber phase that results from such disturbance poses the rainforest silviculturist with one of his most difficult problems because the vines can strangle small trees and saplings with consequent degrade of timber quality, weigh down and deform the young trees, and severely 5

depress the potential growth rate of the desirable stems by the sheer weight of competition and shading.

Well-drained Rainforest Open Bay TA. Photo credit Ian Whyte 1974. 6

Vanimo Rainforest understorey. Photo credit Ian Whyte 1974.

Vanimo Rainforest understorey. Photo credit Ian Whyte 1974. The cutting of climbers is therefore an important silvicultural operation in most, if not all, tropical rainforest treatments and one that is not without difficulties, since too early a cleaning after treatment often merely rejuvenates the climber phase. For up to five years after regeneration activities commence, it may be necessary to continue climber cutting.

Although vines are most numerous in gaps and along rainforest margins (e.g., roads, river fronts, where the virtually continuous curtain of climbers have done much to perpetuate the myth of the impenetrable rainforest) they are also found in well developed, mature rainforest stands. The climbers in such sites are generally large, with their crowns extending over and through the higher tree canopies and thus making a larger contribution to the shadiness of the lower levels. These vines often tend to bind the trees so firmly together that sometimes a large tree can be cut through at the base and still not fall, or else in falling may bring many other trees with it. To avoid the dangers inherent in felling trees that are bound so close together, as well as to improve the lighting for regeneration purposes and to facilitate access, climber cutting ahead of logging is a common routine rainforest treatment. Baining Track 1968 Gazelle East New Britain. 1968. Photo credit Ian Whyte. Like many other light demanding rainforest plants, the seedlings of many climbers can germinate and survive for some years beneath dense shade, so that throughout the rainforest there is usually a reservoir of young vines waiting for the opportunity to assume active growth. Stranglers are an interesting and distinctive life form, which is largely confined to rainforest and rather unevenly distributed throughout it. These are trees which start life as epiphytes, their seeds germinating in the crowns of existing trees, often in branch angles where moisture and plant debris accumulate to provide a suitable seed bed. The young stranglers make slow early growth while sending their roots down from the host tree to the soil. Once contact with the soil is made, growth increases while the roots grow around the host. Probably in all cases, stranglers weaken the vigour of the host, and thus are to be regarded as weeds. In many instances the stragglers in time may kill the host by competition, strangulation of the stem and shading of the crown. When the host dies, the straggler remains as a tree, which can maintain an independent existence. Ficus spp are the most typical. The other life forms that are found in rainforest – epiphytes, parasites and semi-parasites, and saprophytes – are of little significance to rainforest management, although they contribute in no small measure to the distinctive appearance of rainforest and are of considerable interest ecologically.

Well-drained levee rainforest Gogol TA. Photo credit Ian Whyte. 9

TREES IN THE RAINFOREST The dominant life form of the rainforest is undoubtedly that of the trees, and to the forester concerned with managing and utilizing these communities.

Cloudy Bay Timber Area Abau. Photo credit Dick McCarthy. Although there are differences both between and within rainforest stands, most communities appear to support approximately 1000 trees per hectare larger than 50 cm diameter breast height. Except in young, even aged patches of rainforest, these trees are from a wide range of sizes, with the smaller size classes containing both trees, which, at maturity, are of small stature, and immature individuals of potentially large trees. The trees, from the smallest to the largest, tend to be arranged into several storeys. The taller trees as might be expected, experience a different microclimate to the smaller ones. Among the tallest rainforest trees are the Araucaria spp (hoop and klinkii pine) found in PNG and eastern Australia. Some of the widest diameter trees are Ficus spp and Agathis spp. In appearance, the trees are usually slender for their height, and show less taper than trees in most other types of plant communities. Crown shape is determined not only by its width and depth, but also by the manner and degree of branching, which can be quite characteristic for a given species. The almost whorled, wide angled branching of Terminalia superba, or the dense compact crown of Diospyros spp. Many rainforest trees coppice freely. The stem characteristics of rainforest trees are rather varied, and often provide useful diagnostic features for identification. e.g., Planchonella spp and Citronella spp are typically fluted for their entire length. The most striking features of many rainforest trees, particularly in the tropics are the growth developments of the lower stem – the buttresses and the stilt roots. Stilt roots are most frequently encountered in swampy sites, including mangrove forests, but can also occur in dryland rainforest.

Muyeng Basengke and stilt roots 1974 Vanimo. Photo credit Ian Whyte.

Terminalia archipelagi west end of New Ireland. Photo credit Mark Coode 1962. 11

Buttresses are a characteristic feature of many rainforest communities. They result from abnormal vertical growth made by large surface roots in the angle where these roots join the stem. Unlike stilt roots, buttresses are mostly found on species, which reach the upper sorties of the rainforest. Because of the difficulties, which these buttressed species create in measuring the trees accurately for forest assessment or growth studies, and in felling; they are of importance in rainforest management. e.g., Alstonia, Slonea, Shorea spp.

Well-drained rainforest Open Bay TA 1974. Photo credit Ian Whyte. 12

Most rainforest trees tend to be shallow rooted, and the feeding roots are usually confined to the top few inches of the soil. Buttressed trees usually lack long taproots. In most rainforest communities, a variety of leaf sizes and shapes can be found. The flowering habits of rainforest trees fit less to a pattern than do the leaves. There is great variety. However, there is one type of flowering, which is virtually confined to rainforest trees in the tropical lowlands. This is where the flowers are born not on the small twigs, but on larger branches and even stems. This is called cauliflory. As the rainfall is lowered and the period of water stress extended, the height of the stands is lowered, fewer stories can be recognized, deciduous species become more common, and epiphytes are fewer as shown by evergreen seasonal and semievergreen rainforest. More adverse soil conditions also result in simplification of the structure, again with lower height and fewer stories, and usually with appreciably smaller trees which, however, tend to be evergreen. The nature of the soil greatly affects the incidence of buttressing and other butt formations on the trees as shown by xeromorphic and swampy rainforest. Reduced temperatures react less markedly on rainforest structure, but leaf size becomes smaller, buttressing decreases and in sites that are appreciably exposed, the height is lowered. These changes extend beyond the tropical rainforest formation into temperate rainforest, which often merges imperceptibly into the adjoining submontane and subtropical rainforest stands. The storeys are further reduced in number, leaves become still smaller, buttressing disappears, while where there is a marked cold winter, deciduousness again becomes evident. Richness of rainforest It has already been indicated that rainforest is phenomenally rich in species of trees, while other life forms add to its floristic complexity. However, there is considerable variation between individual stands of rainforest. The richness of the flora appears to vary through two causes – one depending upon the wealth of the regional flora and the other upon the suitability of the site for the trees from this flora to grow.

Well drained rainforest Gogol TA. Photo credit Ian Whyte. Floristic Origin The origins of rainforest flora are recognized as probably coming from two sources – one of pan tropic origin and the other of southern or Antarctic origin. In tropical rainforest, few tree species are common to any of the great regions of occurrence. Some as Slonea spp, diospyros spp, are common to three or more sites. Composition of Rainforest Stands. Rainforest is of a very mixed and complex composition. In tropical rainforest, many species occur but only a few are common. Hence, ecologists often refer to rainforest communities as forest types. In general, the PNG vegetation classification is based on the structural formation of the vegetation. Six structural formations are recognized – forest, woodland, savanna, scrub, grassland, and mangrove communities. While the greater proportion of rainforest communities (or forest types) are of very mixed composition, there are several instances but not in PNG of stands with a tendency towards single species dominance. The dominant species in these stands is characteristically the larger trees (a feature which attracts foresters). More often it is the dominance of several related species as the frequent occurrence e.g., in Malaysian forests, the dominance of the family Dipterocarpaceae.

Forest Structural Formations Within the forest structural formation, several forest types are recognized. Low altitude forests on plains and fans below 1000m

Forest types range from large to medium crowned forest with species as Pomeria, Octomeles, Alstonia, Ficus, to open forest with species as Planchonia, Instia, Vitex, Nauclea to small-crown forest with species as Casuarina, Instia, Campnosperma to Terminalia brassii forest.

Low altitude forests on uplands below 1000 m

Forest types range from large, crowned forest, with species as Pometia, Canarium, Anisoptera, Cryptocarya, terminalia, Syzygium, Ficus, Celtis, Dysoxylum to medium crown with to small-crowned forest

Lower montane forest above 1000 m

Forest types range from small, crowned forest with species as Nothofagus, Lithocarpus, Castanopsis, to small, crowned forest with conifers as Araucaria sp or Podocarpus.

Montane forest – above 3000 m

Forest types with exceedingly small, crowned forest

Dry seasonal forest

Forest type – dry evergreen forest including species as Acacia, Syzygium, Mangifera, Flindersia, Grevillea

Littoral forest

Forest types range from mixed forest to forest with Casuarina or Melaleuca

Seral forest

Forest types range from riverine mixed successions to successions with Casuarina or Eucalyptus deglupta or Terminalia brassii

Swamp forest

Forest types range from mixed swamp forest to swamp forest with Melaleuca or terminalia or Campnosperma

Estuarine communities

Mangrove forest type

New Guinea Forests – Structure, Composition and Management. (Havel) Havel7 published a detailed study8 in 1972 detailing the usefulness of forest typology to forest management in PNG. The purpose of this study was to point out the relevance of ecological studies to the management of the very varied forests of PNG.

Joe Havel with students studying botanical specimens at the PNG Forestry College Bulolo1964. Photo credit Dept. of Forests Port Moresby. Nature of Study The structure and composition of each of the major forest types of PNG was illustrated by a representative profile, and its management problems discussed, particularly those relating to utilisation and silviculture. Major Trends in Forest Types of PNG. The forest types of PNG are arranged along two gradients: the moisture gradient in the lowlands and the temperature gradient in the Highlands.

In this study, Joe Havel acknowledged the assistance of staff and students of the Bulolo Forestry College for assistance in the collection of field data.

Moisture Gradient in the Lowlands The factors determining the moisture regime are the magnitude and seasonality of rainfall, operating on a regional scale, and topography and soil texture, operating on a local scale. Very Wet Sites At the wet end of the lowland series are the mangroves, which reach their optimum development in the delta of the southern rivers, as the Purari, Kikori and Fly. See Figure 2A below.

Tidal Mangrove Forests Cloudy Bay T A near old Robinson River Plantation submerged wharf. Photo Credit Dick McCarthy.

Mangrove Forests Gulf of Papua Delta. Photo credit Dick McCarthy.

Abau Island

Mangrove Forests Cloudy Bay T A. Photo credit Dick McCarthy. 19

Figure 2 B above, details a swamp forest inundated by stagnant fresh water. Common dominants include Dillenia spp, Terminalia brassii, and Planchonia timorensis.

Swamp forest Cloudy Bay T A. Note stagnant water Photo credit Dick McCarthy.

Swamp forest Cloudy Bay T A. Note decaying vegetation. Photo credit Dick McCarthy.

Sites with Optimal Moisture Regimes

Figure 3 A (p 21) depicts undisturbed lowland rainforest of three strata of trees, abundant epiphytes, and climbers as well as relatively poorly developed shrub and herb layer. Here no species is of overwhelming importance, instead there is a rich mixture of species, genera, and families.

Vanimo lowland rainforest. Photo credit Ian Whyte 1974. Figure 3 B (p 21) represents riverine forest. This can be species as Eucalyptus deglupta forest or Octomeles sumatrana forest. It is characterised by good drainage and only temporary flooding. It is essentially a seral stage, colonising river deposits and eventually giving way to lowland rainforest. Both species also colonise new deposits of volcanic ash.

Natural E., deglupta (Kamarere) regeneration Puwani River Vanimo 1974. Photo credit Ian Whyte.

E. deglupta stand New Britain. Photo credit John Davidson 1968.

Photo One

Photo two

Photo one. Kamarere Forest New Britain. Photo credit I Whyte 1968. Photo two. Kamarere forest (E. Deglupta) North Coast New Britain. Photo credit New Horizons 1973 Dept of Forests PNG. 23

Topographically Dry Sites

A drier variant of the lowland rainforest occurs on porous volcanic deposits and on ridges as described in figure 4 (p 24). There is a tendency towards one-species dominance resulting in better overall utilisation and easier regeneration. The dominants tend to vary from region to region. In mainland New Guinea the most important species is Anisoptera polyandra. In New Britain, the main species is Pometia tomentosa and by two species of Calophyllum in Bougainville.

Pometia tomentosa drier lowland rainforest Cloudy Bay TA. Photo credit Dick McCarthy.

Anisoptera polyandra forest near Lae, Morobe District. Photo credit New Horizons 1973.

Climatically Dry Sites

Laloki River riverplain forest near Port Moresby like monsoon forest from Brown River with accompanying dried forest of Eucalypt woodland. Photo credit D McCarthy.

Laloki River riverplain forest near Port Moresby like monsoon forest from Brown River with accompanying dried forest of Eucalypt woodland. Photo credit D McCarthy. 27

The drier forests depicted in figure 5A and 5 B (p 26), present a bewildering floristic mixture comprising Australian Acacias and native rainforest species. In both these forests, the leaves tend to be more leathery, and they accumulate in thicker layers than the lowland rainforest. These forests have in common relatively open tree strata and poor development of epiphytes.

Eucalypt Savannah near Port Moresby. Photo credit Dick McCarthy.

Interspersed with monsoon belt is the transition zone and widespread across the dry sites is the eucalypt savannah woodland, as depicted in figure 5C (p 26).

Fresh water swamp

Eucalypt savannah woodland

Lowland monsoon rainforest

Mixture of Eucalypt savannah woodland, freshwater swamp, and lowland monsoon rainforest along water courses along Papuan South Coast. Photo credit D McCarthy.

In the lowland moisture gradient, the lowland rainforest is the most complex type both structurally and floristically. Lowland rainforest is characterized by development of three tree strata, abundance of climbers and epiphytes and the prevalence of evergreen mesophyll species of many genera and families. With departure towards the wet or dry end of the moisture gradient results in reduction of both floristic and structural complexity.

Altitudinal Temperature Gradient The altitudinal gradient from sea level to the summit of Mt. Wilhelm (4500m) is rather complex. It incorporates not only marked changes in temperature, but also in insolation, humidity, and exposure. The rate of change is not uniform. Lower Altitudes

The lowland ridge forest, dominated by Anisoptera and Hopea, in most of the high rainfall areas merges at its upper limit into a type dominated by Fagaceae, such as Castanopsis acuminatissima. It may contain Araucaria emergents as Araucaria cunninghamii, A, hunsteinii and Agathis alba. Figure 6 (p 30) depicts all three situations.

Bulolo airstrip and Su su’s in background. Photo credit Ian Whyte 1975.

Kinoi felling a klinkii pine on the Bulolo – Watut ridge. CNGT logging operations. 1969. Photo credit Ross Lockyer.

Bulolo Forest Vegetation. Photo credit Ian Whyte 1975.

Bulolo Forestry College Mensuration Classes lower montane forest. Photo credit Leon Clifford. 33

Middle Altitudes Merging with upper limit of the Castanopsis dominated forest is a forest dominated by Nothofagus. Figure 7A below comes from an altitude of 2210 m on Mt Kaindi.

Nothofagus forest located about 2850 m above sea level. Photo credit New Horizons, Dept of Forests PNG 1973.

Upper Altitudes From approximately 3,000 m above sea level, low heavily mossed thicket forests of Decaspermum, Rapanea, Olearia and scattered individuals of Podocarpus.

Moss forest – Finisterre Range, 3084 m above sea level. Photo credit New Horizons, Dept of Forests PNG 1973. The proportion of marketable species is high in all segments of the altitudinal gradient up to 3000 m. The chief limitation is access. In the Highland valleys, anthropogenic grasslands occupying former forest sites, were now being planted by the Dept. of Forests extension programs, with exotics better able to cope with impoverished soils and grass competition, rather than the indigenous araucarias. 36

CSIRO Contribution to PNG’s Botanical Knowledge [Granger] In PNGAF Magazine Issue # 7 of the 11th of January 2021, Ken Granger (TPNG forests 1963-1970) described the contribution of CSIRO to PNG’s forest resource and botanical knowledge 1953-1969. Ken described the fourteen integrated land resource surveys that CSIRO undertook during the period 1953-69, with the aim of identifying areas suitable for accelerated development. The resulting reconnaissance-level regional survey reports and maps provided extensive baseline information for national development planning. Substantial botanical collections carried out during the surveys contributed greatly to the Papua New Guinea National Collection at the Lae Herbarium. Forest Resources and Vegetation Mapping (Hammermaster TPNG Forests 1956-1979) & Saunders

Forest Resources and Vegetation Mapping E T Hammermaster and J C Saunders CSIRO/PNGRIS 1995.

Hammermaster ET and Saunders J C 1995 FOREST RESOURCES AND VEGETATION MAPPING OF PAPUA NEW GUINEA PNGRIS publication #4. ISBN 0642196087 prepared by CSIRO for AusAID.

PNGAF Magazine Issue # 8 page 42-43 described the forest resources and vegetation mapping project of PNG by Hammermaster and Saunders. It reflects the progress made in mapping PNG vegetation since the 1970’s with the advent of the computer era and associated digitisation.

10Forest

Zones of PNG Map prepared by Hammermaster ET and Saunders J C 1995.

The Silvicultural Significance of Floristic Composition The forester responsible for managing rainforest with the primary aim of producing timber with a ready market is most affected by the composition of the rainforest. Apart from the obvious importance of knowing which merchantable species are present and in what quantities, the recognition of forest types can greatly simplify the practice of sound silviculture. Different communities are apt to respond in different ways to a particular silvicultural technique and, by appreciating the differences in composition of rainforest within any area, adequate treatments can be applied to each with a greater likelihood of success. Stands showing a tendency towards single species dominance have a particular appeal to the forester. Such stands are usually easier to treat than forests of more mixed composition. Relation of Rainforest to other Vegetation Types. Rainforest does not exist in isolated condition. Often the junction between rainforest and its neighbour is a merging one that cannot be precisely defined.

FOREST RESOURCES AND VEGETATION MAPPING OF PAPUA NEW GUINEA PNGRIS publication #4. ISBN 0642196087 p

Most rainforest occurs on well-drained soils. Riverine Associations

Pit and first colonising trees Gogol TA. Photo credit Ian Whyte 1971.

Pit floodplain secondary forest and dry terrace rainforest Gogol TA. Photo credit Ian Whyte 1971.

E. deglupta stands.

E. deglupta stand New Britain. Photo credit John Davidson 1968.

Itam with a girth stick measuring T. brassii Mom Hill swamp, September 1964.

Swamps Rainforest often extends into swampy sites, where the vegetation is still able to maintain a rainforest structure. These communities have been classed as swampy rainforest, a rather broad type that should probably be divided into several distinct sub functions on structural grounds. When the extent of inundation becomes more severe, the structure changes and results in many distinct plant communities, which depend on their existence on such features as the depth and period of inundation, the degree of water movement, and the minute local changes into topography. Freshwater swamp series, The permanent swamp sequence occurs where the water-table is always or near the surface. The boundary with rainforest is sharp, the sequence commencing with a tall, two-layered swamp forest in which understory usually contains Metroxylon sagu, the sago palm. Sometimes, the over story consists of almost pure Campnosperma spp, but more usually it is of mixed composition. This gives way in turn to a lower, more open swamp woodland, than a swamp savannah of scattered trees over a dense, tall grass layer, and finally to an herbaceous swamp of various Cyperaceae, up to 12 ft high, bound together with pitcher plants (Nepenthes spp). The fluctuation swamp sequence is found on mineral soil in areas fed by streams, which flood frequently. This merges gradually into rainforest on the better-drained sites. The sequence, which starts with a tall, two storied seasonal swamp forest, which passes to open seasonal swamp forest as the upper storey (up to 90feet high) becomes more scattered over the dense under storey. The upper storey finally disappears to leave seasonal swamp woodland consisting of a single, dense storey of Metroxylon up to 40 feet high: The “sago swamps.” This in turn gives way to an herbaceous swamp, here composed of Phragmite karka and other grasses up to 12ft in height. The semi-seasonal swamp sequence occurs in very low-lying areas which, however, receive little influx of water during the dry season. The sequence is like the fluctuating swamp series, in that it passes from seasonal swamp forest to open seasonal swamp forest, seasonal swamp woodland and finally to herbaceous swamp. However, in the earlier stages Pandanus spp replace the Metroxylon, while the herbaceous swamp is dominated by sedges, not grasses. The seasonal swamp sequence found on mineral soil subject to distinct seasonal inundation. It often contains small permanent swamp of Saccharum spp, up to 3 ft high. This community in turn is enriched by the entry of scattered trees and then changes rapidly to a seasonal dry land forest. Saltwater Swamp Series The tidal mangrove sequence, which occurs between the dry land rainforest and the sea. The boundary with the rainforest is sharp, passing to a one or less commonly two-storied mangrove forest up to 80 ft high. On the New Guinea coast the mangrove forest shows a floristic zonation, with Heritiera littoralis dominating the stands nearest the dry land, then Bruguiera gymnorrhiza and finally Rhizophora mucronata at the seaweed edge, which it bounds a lower, more open, mangrove woodland dominated by Ceriop tagal.

Abau Island

Abau Island and mangroves. Cloudy Bay TA. Photo credit Dick McCarthy. Within the mangrove forest region, a separate series, the mangrove marsh sequence occurs, apparently under the influence of changing salinity. The communities here are all dominated by Avicennia alba c.f. marina and vary from dense singled storied mangrove woodland up to 40 ft high to a rather inaptly named mangrove thicket of scattered trees up to 20 feet high with extensive areas of bare swamp between the trees. The brackish water sequence is found in the transition between some of the freshwater swamp forest and mangrove forests with a mangrove fern savannah. Brackish water interface swamp vegetation Papa Lea Papuan Coast. Photo credit Dick McCarthy.

The estuarine sequence occurs near the mouth of rivers where there is a frequent fresh water and salt water. It is typified by swamp thicket of Nipa fruticans occurring as a narrow strip along the rivers. Although not dependent on poor drainage for its occurrence, mention should be made here of the narrow strip of littoral woodland found facing the sea in areas where well drained sandy shores occur. These are typified by the “Barringtonia formation” of the southwest Pacific, a dense thicket up to 60 ft in height, and occasionally taller, dominated by Barringtonia speciosa and containing many other trees and numerous vines. On the seaward side this faces the even more widespread (pantropic) Ipomoea pes-caprae community of sand-binding vines along the beach; inland it merges into rainforest. Its occurrence is determined by the salt-laden sea winds. Casuarina quisetifolia is a common species dominating extensive well-drained coastal areas in pure stands. It appears, to result from disturbance. The Casuarina replacing the littoral woodland on recently exposed sand ridges or where fire has destroyed the Barringtonia community.

Natural stand Casuarina equisetifolia Cloudy Bay TA Photo credit D McCarthy.

1917 avenue planting Casuarina equisetifolia Ela Beach Roadway Port Moresby by H W Champion. Photo credit Dick McCarthy. More deliberate activity by man has resulted in large areas of coconut palms also having replaced littoral woodland.

Sagarai Gadaisu TA Mariawatte Plantation 1976. Photo credit Ian Whyte.

The vegetation types replacing or adjoining rainforest in sites subject to frequent inundation or constant sea-wind exposure are clearly the most complex. An understanding of their ecology is essential not only to forest management but to many aspects of sound land use. Many of the natural communities are of considerable economic value: some of the forest which can be classified as rainforest provide valuable timber species; mangrove forests yield among the highest financial returns per acre of tropical forest; while to the native inhabitants the many palms of these swamp communities yield a host of necessary products, ranging from thatch for their homes and starch (sago) as a staple food-stuff to “cigarettes” from the young Nipa leaves, palm wine and toddy for their solace. For the forester, there is interest in the fact that many of the associated communities, although occurring under less favourable conditions, are of greater value than the rainforest itself. For example, many of the pine and eucalypt-dominated forest are cases in point. Here, the ecological similarity between Pinus and Eucalyptus is of interest to the forester. It is coincidence that these two genera are those widely used in deliberate schemes throughout the world to convert sites capable of supporting rainforest to pure stands. But perhaps to both ecologist and forester the most important point brought out is the effect of fire on determining that probably a greater length of inland rainforest boundary is determined by fire than by all other factors together. Where suitable species are available to take advantage of this fire effect, as with Pinus and Eucalyptus, the resultant fire induced stands may be of great forestry importance. Where such species are lacking, the resultant vegetation may be nothing but a serious problem to the forester. The importance of fire in limiting rainforest distribution can never be overstressed.

Bibliography George Baur. The Ecological Basis of Rainforest Management. Andre Mayer Fellowship 1961-62. FAO. Barry Conn and Kipiro Damas. Trees of Papua New Guinea Vol 1-3 www.pngtrees.com Dept of Forests PNG. New Horizons. Jacaranda Press 1973 ISBN0701681845. Hammermaster ET and Saunders J C 1995 FOREST RESOURCES AND VEGETATION MAPPING OF PAPUA NEW GUINEA PNGRIS publication #4. ISBN 0642196087 J. J. Havel (1972) New Guinea Forests—Structure, Composition and Management, Australian Forestry, 36:1, 24-37, DOI: 10.1080/00049158.1972.10675567 T C Whitmore 1990. An Introduction to Tropical Rain Forests. ISBN 0194424480

ACRONYMS ACT AEC AFS AFPNG AIF AMF ANBG ANGAU ANU APMF APPM ASIO ASOPA BCOF “Beer Time” BFC BGD BUC C cm CALM CFA CNGT CRE CRE

CSIRO CHAH DASF DEPT DOF E.g. Etc FAO F &TB FPRC Forkol GIS ha IBRD IFA ITTO L of N

Australian Capital Territory Administrators Executive Committee Australian Forestry School Association of Foresters of PNG Australian Infantry Forces Australian Military Forces Australian National Botanical Gardens Australian New Guinea Administrative Unit Australian National University Australian Paper Manufacturers Forestry Pty Ltd Australia Paper and Pulp Manufacturers Australian Security Intelligence Organisation Australian School of Pacific Administration British Commonwealth Occupational Force 1945-52 Any time. Bulolo Forestry College Bulolo Gold Dredging Company Bulolo University College Commonwealth Centimetre Western Australian Department of Conservation and Land Management Commonwealth Forestry Association Commonwealth New Guinea Timbers Bulolo Commander Royal Engineers CRE is a term inherited by RAE from RE and is the term for the Commanding Officer of a RAE unit which is headed by a Lt Col. Although the officer is called the CRE the name is also used for the name of his unit. E.g., CRE Aust Forestry Group or 1(NG Forests). Commonwealth Scientific and Industrial Research Organisation Council of Heads of Australasian Herbaria Dept of Agriculture, Stock and Fisheries Department Department of Forests For example et cetera (more of the same) Food and Agriculture Organisation Forest and Timber Bureau Canberra Forest Products Research Centre Hohola Bulolo Forestry College Geographic Information Systems Hectare International Bank for Reconstruction and Development Institute of Foresters of Australia International Tropical Timber Organization League of Nations 48

m3 MM NAA NARI NB no. NG NGF NGIB NGVR NZ NSW P or p PIB PIR PNG PNGAA PNGAF PNGFA PNGFIA PNGRIS PNGUT POM Q QF RAE RPC SFM SP UK UN Unasylva UNE UNI UNITECH UNRE UPNG UQ US USA TPNG TUBL TA TA TRP VSF WA WB WW2

cubic metre Military Medal National Archives Australia National Agriculture Research Institute New Britain Number New Guinea New Guinea Forces (relates to plant collection of Lae Herbarium) New Guinea Infantry Battalion New Guinea Volunteer Rifles New Zealand New South Wales page Papuan Infantry Battalion Pacific Islands Regiment Papua New Guinea Papua New Guinea Australia Association Papua New Guinea Australian Foresters Magazine Series Papua New Guinea Forest Authority PNG Forest Industries Association Papua New Guinea Resource Information System PNG University of Technology Port Moresby Queensland Queensland Forestry Royal Australian Engineers/Australian Army Royal Papuan Constabulary Sustainable Forest Management South Pacific United Kingdom United Nations Journal of FAO of UN University of New England Armidale NSW University University of Technology Lae PNG University of Natural Resources and Environment University of Papua New Guinea University of Queensland United States United States of America Territory of Papua and New Guinea Territory United Brewery Ltd Timber Area Timber Authority Timber Rights Purchase Victorian School of Forestry Western Australia World Bank WORLD WAR 2