Browsing by Browse by SEO 2008 "820104 Native Forests"

Rapid decline and death of rural Eucalypts trees of all ages and species have been reported in the farmscapes of regional Australia due to various environmental and farming management related factors. The identification of existing farm tree species is important for long term management strategies to provide ecosystem stability in the region. This study explored the feasibility of structural attributes of LiDAR and spectral and spatial characteristics of high resolution remote sensing data to identify and map Eucalyptus tree species. An object based image segmentation and rule-based classification algorithm were developed to delineate tree boundaries and species classification. The integration of two datasets improved the classification accuracy (65%) against their separate classification (52% and 41%, respectively). The identification of tree species will help in getting first-hand information on existing farm trees, which may be used in assessing tree condition in time series related to management practices and complex dieback problem.

Mixtures of 'Eucalyptus globulus' Labill. and 'Acacia mearnsii' de Wildeman are twice as productive as 'E. globulus' monocultures growing on the same site in East Gippsland, Victoria, Australia, possibly because of increased nitrogen (N) availability owing to N₂ fixation by 'A. mearnsii'. To investigate whether N2 fixation by 'A. mearnsii' could account for the mixed-species growth responses, we assessed N₂ fixation by the accretion method and the 15N natural abundance method. Nitrogen gained by 'E. globulus' and 'A. mearnsii' mixtures and monocultures was calculated by the accretion method with plant and soil samples collected 10 years after plantation establishment. Nitrogen in biomass and soil confirmed that 'A. mearnsii' influenced N dynamics. Assuming that the differences in soil, forest floor litter and biomass N of plots containing 'A. mearnsii' compared with 'E. globulus' monocultures were due to N₂ fixation, the 10-year annual mean rates of N₂ fixation were 38 and 86 kg ha⁻¹ year⁻¹ in 1:1 mixtures and 'A. mearnsii' monocultures, respectively. Nitrogen fixation by 'A. mearnsii' could not be quantified on the basis of the natural abundance of 15N because such factors as mycorrhization type and fractionation of N isotopes during N cycling within the plant confounded the effect of the N source on the N isotopic signature of plants. This study shows that 'A. mearnsii' fixed significant quantities of N₂ when mixed with 'E. globulus'. A decline in δ15N values of 'E. globulus' and 'A. mearnsii' with time, from 2 to 10 years, is further evidence that N2 was fixed and cycled through the stands. The increased aboveground biomass production of 'E. globulus' trees in mixtures when compared with monocultures can be attributed to increases in N availability.

The bark of eucalypt trees is a significant habitat attribute of forests and woodlands, with different bark types supporting varying populations of invertebrate and vertebrate fauna. Bark also contributes to fuel load in wildfires and hazard reduction burning, with a concomitant loss of habitat and modification of habitat resources. We compared the composition and abundance of tree trunk invertebrates inhabiting four eucalypt bark types and determined the impact of burning the bark on population abundance and community composition. Trees of four bark types (gum, box, stringy bark, iron bark) were selected at three sites and arthropod traps placed on burnt and unburnt trees of each type. Traps were left in place for 12 days and arthropod preferences for the four bark types (burnt and unburnt) were analysed. The total number of arthropods differed between bark types, with stringy bark and iron bark supporting the largest numbers of invertebrates and the most diverse communities. Burnt stringy bark and gum bark had reduced arthropod abundance compared to unburnt bark. The study highlights an ecological consequence of fire on an aspect of invertebrate habitat, with flow-on effects for vertebrates, that should be considered in fire management, as greater areas of land are subject to frequent hazard reduction burning in eastern Australia.

Laboratory measurements of the spectral reflectance of leaves from eleven common eastern Australian eucalypts were made over the 400-2400 nm range using an Infra-Red Intelligent Spectroradiometer (IRIS) spectroradiometer. Spectral differences among the different species were studied in terms of reflectance (550 nm, 630 nm, 800 nm, green peak maximum reflectance and chlorophyll well maximum absorption) and wavelength positions (red edge, green peak maximum reflectance, cholorophyll well maximum absorption and red edge inflection point). This paper discusses the differences between the species in the visible and red-edge regions only. Results indicate that, while spectra from different eucalyptus species appear similar in terms of shape and positions of absorption features, statistically significant differences do exist. These differences are in terms of absolute reflectance, depths of absorption features and the relative position of change in terms of the wavelength.

General non-site-specific allometric relationships are required for the conversion of forest inventory measurements to regional scale estimates of forest carbon sequestration. To determine the most appropriate predictor variables to produce a general allometric relationship, we examined 'Eucalyptus pilularis' aboveground biomass data from seven contrasting sites. Predictor variables included diameter at breast height (dbh), stem volume, dbh² × H, dbh × H and height (H). The data set contained 105 trees, ranging from 6 to over 20,000 kg tree⁻¹, with dbh ranging from 5 to 129 cm. We observed significant site differences in (1) partitioning of biomass between the stem, branch wood and foliage; (2) stem wood density and (3) relationship between dbh and height. For all predictor variables, site had a significant effect on the allometric relationships. Examination of the model residuals of the site-specific and general relationship indicated that using dbh alone as the predictor variable produced the most stable general relationship. Furthermore, the apparent site effect could be removed by the addition of a constant value to the measured diameter (dbh + 1), to account for the differing diameter distribution across the seven sites. Surprisingly, the inclusion of height as a second predictor variable decreased the performance of the general model. We have therefore demonstrated that for 'E. pilularis' a general allometric relationship using dbh alone as the predictor variable can be as accurate as site-specific allometry, whilst being applicable to a wide range of environments, management regimes and ages. This simplifies regional estimates of aboveground biomass from inventory measurements, eliminating the need for site-specific allometric relationships or modifiers such as height, wood density or expansion factors.

Calcium oxalate (CaOx) crystals are a common natural feature of many plant families, including the Leguminosae. The functional role of crystals and the mechanisms that underlie their deposition remain largely unresolved. In several species, the seasonal deposition of crystals has been observed. To gain insight into the effects of rainfall on crystal formation, the morphology, distribution and accumulation of calcium oxalate crystals in phyllodes of the leguminous 'Acacia' sect. 'Juliflorae' (Benth.) C. Moore & Betche from four climate zones along an aridity gradient, was investigated. The shapes of crystals, which include rare Rosanoffian morphologies, were constant between species from different climate zones, implying that morphology was not affected by rainfall. The distribution and accumulation of CaOx crystals, however, did appear to be climate-related. Distribution was primarily governed by vein density, an architectural trait which has evolved in higher plants in response to increasing aridity. Furthermore, crystals were more abundant in acacias from low rainfall areas, and in phyllodes containing high concentrations of calcium, suggesting that both aridity and soil calcium levels play important roles in the precipitation of CaOx. As crystal formation appears to be calcium-induced, we propose that CaOx crystals in Acacia most likely function in bulk calcium regulation.

In many plant species osmotic-adjustment (OA) is an important drought tolerance mechanism. Most research into OA has investigated cropping and forage species, by comparison little is known about the process in non-agronomic plants. The 'Acacia' genus is one of the most widespread and species rich taxons of woody plants in Australia. Members of the genus display morphological and physiological traits that augment their general utility; including rapid growth (enhanced carbon sequestration), nitrogen fixing capacity and above average drought/dehydration tolerance (reduced water consumption). A limited number of 'Acacia' species are cultivated on a global basis to provide a food source and raw materials for various industries. Given the potential of the genus and in the context of currently accepted climate change paradigms, a more complete knowledge of 'Acacia' ecophysiology is required. As water availability becomes progressively limited, a superior capacity to tolerate drought is evidently important. Capacity to recover from water deficit, however, and grow efficiently under conditions of restricted and often punctuated water availability is justifiably of greater significance. This study investigated the fundamental physiological responses of several 'Acacia' species to water stress and subsequent recovery. Particular attention was given to the drought tolerance mechanism of osmotic-adjustment and its relationship to the ecology of 'Acacia'. A separate section of this research surveyed seasonal and climate zone induced changes in leaf/phyllode solute composition and osmotic potential for a cohort of endemic Australian 'Acacia' species. These species were selected to cover a climatic gradient from semi-arid to sub-tropical/coastal habitats. Aspects including the degree of xeromorphy, the ecology and evolutionary heritage of the species and the influence of these factors on resultant physiological responses during drought and recovery were considered.

In north-eastern New South Wales (NSW) the Regional Forest Agreement process has transferred more than 400 000 ha of state forests to national park, and restricted silviculture to 'single tree selection' and a light form of 'Australian group selection'. While these silvicultural systems are theoretically well suited to ecologically sustainable forest management, there is concern that in their current form they are not achieving adequate regeneration or optimising the growth of that regeneration. This is of particular concern for mixed-species blackbutt forest, for which there is no quantitative research concerning the growth and composition of regeneration within group-selection gaps. We address this issue by: (1) quantifying the effect of gap size, and other gap characteristics including distance from gap edge, on the growth of regeneration; and (2) assessing the effect of gap size on the composition of regeneration. We use the answers to these questions to recommend a gap size for group selection silviculture in mixed-species blackbutt forests in north-eastern NSW. We measured attributes describing the growth and composition of regeneration in nine circular group-selection gaps in mixed-species blackbutt forest near Coffs Harbour and Wauchope. These gaps contained 14.5-15.5-y-old regeneration and provided three replicates of small (0.27-0.3 ha). medium (0.45-0.67 ha) and large (0.93-0.97 ha) gaps. ANOVA testing indicated significantly ('P' < 0.05) lower height, diameter and volume growth of dominant blackbutt stems up to five metres from gap edge. Outside this zone growth remained fairly constant, indicating dominant blackbutt trees were susceptible to suppression only in close proximity to gap edges. Multiple regression analysis confirmed the relatively short distance from gap edges over which suppression occurred, with distance to closest gap edge explaining a small proportion of the variation in the models fitted for tree- and plot-level growth. The origin of blackbutt regeneration within gaps was a significant effect in tree-level growth models, with planted stems having increased diameter and volume growth compared with stems regenerated from natural seedfall. Gap size had no significant effect on the composition of regeneration. We conclude that for the range of gaps tested, 1-ha gaps are optimal for growth because they minimise the proportion of gap within 5 m of the retained forest edge, without altering composition. Larger gaps have also been shown to have operational and economic benefits compared with smaller gaps.

Significant increases in aboveground biomass production have been observed in mixed plantations of 'Eucalyptus globulus' and 'Acacia mearnsii' when compared to monocultures. However, this positive growth response may be enhanced or lost with changes in resource availability. Therefore this study examined the effect of the commonly limiting resources soil N, P and moisture on the growth of 'E. globulus' and 'A. mearnsii' mixtures in a pot trial. Pots containing two 'E. globulus' plants, two 'A. mearnsii' plants or one of each species were treated with high and low levels of N and P fertiliser. After 50 weeks, 'E. globulus' plants grew more aboveground biomass in mixtures than monocultures. 'A. mearnsii' were larger in mixtures only at low N, where both species were similar in size and the combined aboveground biomass of both species in mixture was greater than that of monocultures. At high N and both high and low levels of P fertiliser 'E. globulus' appeared to dominate and suppress 'A. mearnsii'. In these treatments, the faster growth of 'E. globulus' in mixture did not compensate the reduced growth of 'A. mearnsii', so mixtures were less productive than (or not significantly different from) E. globulus monocultures. The greater competitiveness of 'E. globulus' in these situations may have resulted from its higher N and P use efficiency and greater growth response to N and P fertilisers compared to 'A. mearnsii'. This trial indicates that the complex interactions between species in mixtures, and thus the success of mixed plantations, can be strongly influenced by site factors such as the availability of N and P.

Conditions for optimal pretreatment of eucalypt ('Eucalyptus dunnii') and spotted gum ('Corymbia citriodora') forestry thinning residues for bio ethanol production were empirically determined using a 33 factorial design. Up to 161 mg/g xylose (93% theoretical) was achieved at moderate combined severity factors (CSF) of 1.0-1.6. At CSF > 2.0, xylose levels declined, owing to degradation. Moreover at high CSF, depolymerisation of cellulose was evident and corresponded to glucose (155 mg/g, ~33% cellulose) recovery in pre hydrolysate. Likewise, efficient scarification with Cellic® CTec 2 cellulase correlated well with increasing process severity. The best condition yielded 74% of the theoretical conversion and was attained at the height of severity (CSF of 2.48). 'Saccharomyces cerevisiae' efficiently fermented crude 'E. dunnii' hydrolysate within 30 h, yielding 18 g/L ethanol, representing a glucose to ethanol conversion rate of 0.475 g/g (92%). Based on our findings, eucalyptus forest thinnings represent a potential feedstock option for the emerging Australian bio fuel industry.

'Eucalyptus' plantations cover more than 20 Mha worldwide and are almost exclusively monospecific. However, in native forests 'Eucalyptus' species often grow in mixtures. Mixed species stands of trees can be more productive than monospecific stands but despite the implications of this effect, for plantations and native 'Eucalyptus' forests, the effects of mixing eucalypts has received little attention. The aim of this study was to examine whether two species that naturally coexist ('Eucalyptus grandis' W. Hill and 'Eucalyptus pilularis' Sm.) grow faster in mixtures than their respective monocultures. Monocultures and 1:1 mixtures, and stands of two initial planting densities (1250 and 2500 trees ha⁻¹), were used to compare the productivity and stand structures of mixtures and monocultures and to quantify inter- and intra-specific competition. Interactions between these 'Eucalyptus' species increased their relative yields in mixtures by 10-30%. This was associated with changes in stand structure where the diameter distributions of both species became less positively skewed (lower proportions of small trees). Mixing effects were relatively consistent as the stands developed suggesting that if this complementarity effect is used in plantations there is considerable silvicultural flexibility, such that these mixed plantations could be used on both shorter rotations for biomass or pulp-logs as well as longer rotations for solid wood products. This study also suggests that interactions between co-occurring 'Eucalyptus' species in natural forests might actually facilitate individual tree growth, in addition to simply enabling co-existence.

The Forgotten Trade examines the effects of a trade of economic and geopolitical significance arising from the role of gutta percha in submarine telegraphy. The study documents relationships and processes along stages of the gutta percha commodity chain, taking into account the peculiarities of the commodity, the actors involved in it, and the environment in which it was found. In that sense the study could be considered a trade ecology: a study of the interaction between a community of actors and the habitat that shaped the particular commodity trade. The thesis considers the effect of global economic forces on local collectors of a forest product. Evidence from commercial archives and trade data collated from contemporaneous colonial and local government reports reveal a history of gutta percha trade that was shaped by the powerful yet idiosyncratic decisions of metropolitan consumers who left control of much of the trade in the hands of others. This dependence helped shape the formation of power positions within the trade, leaving regional and local actors in control of collection and supply. In the Southeast Asian region and in Sarawak, prevailing conditions that included effective trade networks, better local knowledge, and colonial administrations that relied upon local elites, lay the ground for the operation of the trade and power positions within it. Economic and social interests as well as geographic and political forces shaped local strategies as the gutta percha trade brought local communities more closely into the world economic system. The study shows how local actors actively sought the opportunities provided by this global trade. It proposes a re-assessment of aspects of nineteenth century Sarawak history, revealing the previously unrecognized way in which the operation of the trade altered communities, and the political economy. It emphasizes the role and responsiveness of local actors and intermediary traders at the so-called periphery of the global trade network. Harnessing world-system, commodity chain and social capital theories, the thesis concludes that the modes and strategies adopted by local collectors and traders were shaped by geographic, political, social and cultural factors. The study also concludes that in order to comprehend the nature of global trade and its effects, we need to understand global to local relationships and responses. It reveals how the theme of an exploiting metropole and exploited periphery tells only part of the story: the so-called periphery may be vulnerable to the external economy but plays a significant role with its own complex responses.

To quantify the climate change impacts of forestry and forest management options, we must consider the entire forestry system: the carbon dynamics of the forest, the life cycle of harvested wood products, and the substitution benefit of using biomass and wood products compared to more greenhouse gas intensive options. This paper presents modelled estimates of the greenhouse gas balance of two key native forest areas managed for production in New South Wales for a period of 200 years, and compares it to the option of managing for conservation only. These two case studies show that forests managed for production provide the greatest ongoing greenhouse gas benefits, with long-term carbon storage in products, and product substitution benefits critical to the outcome. Thus native forests could play a significant part in climate change mitigation, particularly when sustainably managed for production of wood and non-wood products including biomass for bio-energy. The potential role of production forestry in mitigating climate change, though substantial, has been largely overlooked in recent Australian climate change policy.

Efforts to support farmers living near forests to achieve sustainable agriculture and natural resource conservation have predominantly focused on services or schemes such as agricultural extension and community-based forest management, with little attention being focused on farmers' local soil knowledge (LSK). This paper provides insights into farmers' LSK, their agricultural and soil conservation practices and economic reliance on natural forests. Household survey (n = 146) and key informant interviews (n = 24) with farmers was conducted in two communes of the buffer zone of Bach Ma National Park, Central Vietnam. The results indicated that 70% of farmers had reasonable LSK, and farmers with comprehensive LSK (21%) were more familiar with their soils and the relationships between essential soil properties that reflect soil problems. Most farmers used soil colour to allocate crop types because of its association with soil fertility or plant yields. Erosion was identified as a major production constraint, yet less than a fifth of farmers had placed soil erosion control measures into practice. However, low-cost techniques, such as growing native plant cover (e.g.“lồ ô” (Bambusa balcooa)), were suggested by a few farmers to address soil loss. The Katu farmers had greater potential to secure LSK as the next generation are continuing to farm, while the Kinh farmers' LSK is threatened by a lack of engagement in farming by the younger generation. However, Katu farmers have less opportunity to use their LSK due to limitations in farm size and cropping options. These findings have raised different challenges to the succession of farmers' LSK for sustainable agriculture and natural resources conservation in the two communes. Finally, this study highlighted the importance of involving farmers' LSK in the early stages of designing and conducting research through forums or workshops to improve relevance and adoption of practices developed so they align with local people's understanding and practice.

There is growing evidence that collection of non-timber-forest products (NTFPs) remains an essential part of livelihoods for people living near protected areas in developing countries. This study examined the nature and level of livelihood reliance of households on the collection and use of NTFPs and alternative income streams for three ethnic groups (Chau Ma, Stieng and Kinh) in a village in the buffer zone adjacent to Cat Tien National Park, Dong Nai province, Vietnam. Household surveys (n = 150) and key informant interviews (n = 10) were conducted to collect data on forest usage, household socio-economy, and collection of NTFPs. About one-third of Chau Ma and Stieng households had a high reliance on NTFPs, while Kinh households having no reliance on NTFPs for their livelihood. The dependence on NTFPs for Chau Ma and Stieng people was a result of limited opportunities for other livelihood options due to a complex set of factors, including among others low education levels and imposed fundamental changes to their traditional livelihoods. For Chau Ma and Stieng people struggling to adjust from a subsistence forest-based livelihood to living outside the forest, around 42% continued to visit the forest for cultural reasons including traditional food and ceremonies, albeit at low to moderate levels (63%). It is proposed that government authorities acknowledge the livelihood role for local people of low-level traditional use of NTFPs. In addition, for those people who are highly reliant on NTFPs, alternative livelihood strategies should be developed further, to better engage their local knowledge and skills in the co-management of the Park forest.

A doubling of aboveground biomass production has been observed in mixtures of 'Eucalyptus globulus' Labill. and 'Acacia mearnsii' de Wildeman when compared with monocultures after 11 years of growth. This study examined to what extent increased nitrogen (N) availability and accelerated rates of nutrient cycling may contribute to increased growth in mixtures. Monocultures of 'E. globulus' (E) and 'A. mearnsii' (A) and mixtures of these species were planted in a species replacement series: 100% E, 75% E + 25% A, 50% E + 50% A, 25% E + 75% A, and 100% A. Litterfall mass increased with aboveground biomass production and was highest in 50:50 mixtures and lowest in monocultures. Owing to higher N concentrations of 'A. mearnsii' litter, N contents of annual litterfall were at least twice as high in stands containing A. mearnsii (32-49 kg·ha¹·year–¹) as in 'E. globulus' monocultures (14 kg·ha¹·year¹). Stands with 'A. mearnsii' also cycled higher quantities of phosphorus (P) in annual litterfall than 'E. globulus' monocultures. This study demonstrated that mixing 'A. mearnsii' with 'E. globulus' increased the quantity and rates of N and P cycled through aboveground litterfall when compared with 'E. globulus' monocultures. Thus, mixed-species plantations appear to be a useful silvicultural system to improve nutrition of eucalypts without fertilization.

Mixed plantations of a 'Eucalyptus' species with a nitrogen-fixing tree species can produce significantly higher quantities of aboveground biomass than monocultures. However, if species or sites are not chosen correctly, one species may suppress the growth of the other and mixtures may be less productive than monocultures. Based on a study of 'Eucalyptus globulus' and 'Acacia mearnsii', this paper discusses the species attributes and site factors that should be considered to improve the probability of increasing biomass production using mixed-species plantations. In an 11-year-old mixed-species trial of 'E. globulus' and 'A. mearnsii' in southeastern Australia aboveground biomass production was twice as high in mixtures containing 50% 'E. globulus' and 50% 'A. mearnsii' than in 'E. globulus' monocultures. There are three main types of interactions that led to this growth outcome: competition, competitive reduction and facilitation. Facilitation occurred as 'A. mearnsii' fixed significant quantities of N, both in monoculture and when mixed with 'E. globulus'. In addition, not only rates of N but also those of P cycling through litterfall were significantly higher in mixed stands than 'E. globulus' monocultures, pointing to the importance of selecting a nitrogen-fixing species that is capable of N fixation and subsequent fast nutrient cycling through litterfall. Mixed stands developed stratified canopies, such that 'E. globulus' eventually overtopped 'A. mearnsii' after 9 years. This resulted in an increase in light capture at the stand level and a reduction in competition for light for 'E. globulus', a relatively shade intolerant species. This illustrates the importance of selecting species based on their height growth dynamics and relative shade tolerances, to ensure that neither species is suppressed by the other and that the less tolerant species is not overtopped by the more shade tolerant species. In addition to species attributes, site factors, such as soil nitrogen, phosphorus and water availability, play an important role in the interactions and processes occurring in mixtures. In a pot trial containing monocultures and mixtures of 'E. globulus' and 'A. mearnsii', mixtures produced more biomass than monocultures of either species at low levels of N fertiliser. However, at high levels of N fertiliser 'E. globulus' suppressed 'A. mearnsii' and the biomass production of mixtures was not significantly different to that of 'E. globulus' monocultures. This suggests that mixtures should only be planted on sites where the processes and interactions between species will increase the availability of, or reduce competition for, a major limiting resource for growth at that site. The accurate prediction of successful mixed-species combinations and sites is difficult due to the limited number of studies on mixtures. A mechanistic approach is required to examine the interactions and processes that occur in mixtures and to demonstrate why certain combinations are successful on some sites and not others.

Mixed species plantations have the potential to exceed the biomass production of monocultures. This study examined the productivity of three mixed species plantations in southeastern Australia. Two of these trials contained a 'Eucalyptus' sp. ('E. saligna' Smith or 'E. nitens' [Deane & Maiden] Maiden) planted with 'Acacia mearnsii' De Wild., and the other contained 'Pinus radiata' D. Don with 'A. mearnsii', 'A. decurrens' Willd., 'E. benthamii' Maiden & Cambage, or 'E. smithii' R. Baker. Each trial contained both monocultures and mixtures, and was replicated three or four times. Tree diameters or heights were smaller in mixture than monocultures for some species (P. radiata diameters of 5.9 cm and 7.0 cm in 2:1 mixtures with 'A. mearnsii' and monocultures, respectively) but tended to increase (not significantly) for other species ('E. nitens' diameters of 10.6 cm and 8.5 cm and 'A. mearnsii' diameters of 9.2 cm and 8.8 cm in 1:1 mixtures and monocultures, respectively). As a result, mixtures were intermediate in aboveground biomass production between monocultures of the mixed species in each trial, or they were not significantly different from the monocultures. Competition for resources other than nitrogen (N), such as light, soil moisture, or other nutrients, appeared to balance any positive effects that might have occurred, such as through increased N availability. For example, foliar N concentrations of 'E. saligna' were higher in mixture (23.1 mg g⁻¹) than monoculture (17.7 mg g⁻¹); however, this did not result in greater aboveground tree biomass. The range of different growth responses from mixing different species in this study and in other studies shows that a fundamental understanding of the underlying processes is required to enable a greater predictive capacity of the circumstances under which mixtures can be successful.

'Acacia' s.s. comprises approximately 1020 species (i.e. just under one-third of all mimosoid legumes) and is almost entirely restricted to, although widespread, on the Australian continent. We investigated variation in the wood anatomy of 12 species from temperate New South Wales in a study concentrating on four recognised taxonomic sections ('Botrycephalae', 'Juliflorae', 'Phyllodineae' and 'Plurinerves'), to elucidate which characteristics are consistent within the sections, having removed climatic effect as much as possible. The sections had great utility in species identification, whereas none of the wood characters reflected the hypothesised phylogeny of the genus. The main consistent difference among species was in ray width (uniseriate versus 1-3 cells wide). All species had distinct growth rings. The vessels had alternate vestured pitting and simple perforation plates. Fibres were generally thick-walled, and many fibres had a gelatinous inner wall (tension wood fibres) and were inconsistently distributed. Axial parenchyma was mainly paratracheal, ranging from vasicentric to confluent and varied greatly in abundance. Prismatic crystals were usually present in chambered fibres and axial parenchyma strands, and also varied in abundance. The variation in these qualitative characters obscures taxonomic differences, but may allow inferences to be made about environmental adaptation.

Whitewood ('Endospermum medullosum') is native to Vanuatu and has been designated as a priority species for plantation development by the Vanuatu Government for timber production after exhaustion of available natural forest supplies. Domestication is well advanced, with first and second-generation seed orchards and considerable silvicultural research having been accomplished, yet development of a plantation estate has been slow. This study analyses the value chain of whitewood on the two main islands of Efate and Santo that have land suitable for growing whitewood, most of the existing processing facilities and the main markets for whitewood products. The value chain is described and pricing along the chain is presented. Interviews with stakeholders identified impediments to the expansion and development of whitewood plantations. Despite a value-added chain existing, the price available to growers often reflects native forest timber prices that are inadequate given the input costs associated with plantation development, therefore providing little motivation to grow whitewood. There is a trend in the market for the highest profits to be taken by owners of key timber processing plant such as portable sawmills, kiln dryers and preservation vessels. However, prices achieved for processed whitewood products generally do not match those of radiata pine products, indicating potential for greater returns for growers and other stakeholders. As a result, landholder participation in plantation establishment is low and is dispersed as many small woodlots. Small-scale growers and processors face technical challenges, including growing of high quality and value stems and timely treatment of sawn timber. Greater capacity for consistency of product quality and the development of new products to maximise utilisation will improve revenue flows to growers.