Internal nutrient recycling through retranslocation (resorption) is important for meeting the nutrient demands of new tissue production in trees. We conducted a comparative study of nutrient retranslocation from leaves of five tree species from three genera grown in plantation forests for commercial or environmental purposes in southern Australia—Acacia mearnsii De Wild., Eucalyptus globulus Labill., E. fraxinoides H. Deane & Maiden, E. grandis W. Hill ex Maiden and Pinus radiata D. Don. Significant amounts of nitrogen, phosphorus and potassium were retranslocated during three phases of leaf life. In the first phase, retranslocation occurred from young leaves beginning 6 months after leaf initiation, even when leaves were physiologically most active. In the second phase, retranslocation occurred from mature green leaves during their second year, and in the third phase, retranslocation occurred during senescence before leaf fall. Nutrient retranslocation occurred mainly in response to new shoot production. The pattern of retranslocation was remarkably similar in the leaves of all study species (and in the phyllodes of Casuarina glauca Sieber ex Spreng.), despite their diverse genetics, leaf forms and growth rates. There was no net retranslocation of calcium in any of the species. The amounts of nutrients at the start of each pre-retranslocation phase had a strong positive relationship with the amounts subsequently retranslocated, and all species fitted a common relationship. The percentage reduction in concentration or content (retranslocation efficiency) at a particular growth phase is subject to many variables, even within a species, and is therefore not a meaningful measure of interspecific variation. It is proposed that the pattern of retranslocation and its governing factors are similar among species in the absence of interspecies competition for growth and crown structure which occurs in mixed species stands.

In Sumatra and Kalimantan in Indonesia and Sabah in Malaysia, the spread of two diseases, aggravated by damage by fauna, and by the humid tropical environment, has forced a change of planted species from Acacia mangium to Eucalyptus pellita and related interspecific hybrids, at a scale unprecedented in the history of plantation forestry. This experience highlights the risks of relying on any single species for large contiguous plantation estates in environments with endemic biotic and abiotic stresses. There is a need to transition to multiple-species plantation forestry, adopting the opportunities for changeover of species and varieties in short-rotation systems. Industry’s responses for coping with this rapid change have been helped by earlier collaborative research on acacia which promoted management practices that conserved site resources and avoided site degradation during the critical harvesting and inter-rotation phase. The current growth rates of E. pellita and its hybrids are lower than that of A. mangium. Estimates of production from plantations and expanding capacity of the pulp and paper mills highlight a risk of significant shortfalls in wood production. Improving the quality and consistency of forest operations and revision and refocussing of research and development are critical to set and achieve realistic targets for stable, incremental improvements in productivity. Each company should consider investing systematically in contemporary adaptive research for developing and applying integrated management practices that are efficient and feasible on large scales and suitable for their circumstances. There is also a critical need for research to understand the dynamics of local human capital and its relationships with the forestry sector, with focus on improving access to a stable labour force.

Vietnam’s forestry sector is facing rising demands for wood to support national and rural economies, and rural livelihoods. A feasible option to meet this demand is to improve productivity in the current plantation estates, especially in those owned by thousands of small growers. Growers have invested in short-rotation acacia plantations primarily for the woodchip market, but are being urged through government policies and pressured by certification bodies and some NGOs to shift to longer rotations, preferentially, for growing saw logs. In this context, we examined the productivity of an Acacia auriculiformis plantation in South Vietnam, over four successive rotations, spanning 25 years. We show that it is possible to increase and sustain wood production in the long term, by applying simple but integrated management practices, recognizing that the conservation of site resources is critical for sustainability. Practices which depleted site organic matter and nutrients lead to a hidden, but high, cumulative loss of production. Given the site and soil damaging practices prevalent in the country, it is likely that production foregone in those sites may be equivalent to the yield from one in every four or five rotations harvested. With sound management including the conservation of site resources, planting the best germplasm, appropriate stocking and judicious use of herbicide, total wood production and the proportion of saw logs (50–70% of the commercial wood at about 7 years of age) can be increased substantially. At the same time, these practices also can promote understory development and diversity in the stand. Such holistic benefits are possible without extending the rotation length and/or thinning, which are likely to raise the levels of risks for small growers, who are not covered by any insurance. Investments and support for small growers to enable higher productivity and value per unit area in their holdings, through sustainable management, would offer practical and low-risk options for the benefits of growers, processors and ecosystems.

Forests are a renewable resource and wood is a valuable and sustainably useable product that contributes to national economies. This value from the forests can be realised in harmony with the functions of forests in the global carbon cycle and as long-term carbon repositories as well as providing other environmental values. This important understanding is missed or ignored in many global forestry forums. After more than two decades of so-called ‘pro-poor’ forestry policies backed by large amounts of research preferentially targeted to advance non-timber forest products and payment for ecosystem services including Reducing Emissions from Deforestation and Forest Degradation, it is difficult to find evidence to back any contention that in any tropical region they have advanced the economic status of forest-dependent or rural communities enabling them to come out of poverty in an enduring way. It is argued here that the sustainable management of native and planted forests, including wood production and processing in rural regions, and greater use of wood products by all of us, can play a much greater role than has been recognised so far for dealing with two major interrelated global challenges. These are poverty reduction in rural forest landscapes, notably in the subtropics and tropics, and to make modest contributions to climate change mitigation globally, especially by recognising the roles of both forests and wood products in the carbon cycle. It is time for a revised narration in the global agenda to raise the potential role of forests as a sustainably manageable resource, free from overzealous calls for forest conservation, but with a more balanced and holistic recognition of the contributions that forests, forestry and the wood-products sector can make to economic and social development. This should be brought effectively into the deliberations of the forthcoming UN Sustainable Development Goals. This would require efforts by the UN and other bodies to bring the private and public sectors into symbiotic partnerships, not as opposing forces as has often been the case.

We report on experimental studies conducted in South Sumatra with interrelated objectives to (i) examine the trends in production covering 30 years, including three rotations of Acacia mangium followed by Eucalyptus pellita which replaced A. mangium for managing the widespread threat of diseases; (ii) understand the effects of inter-rotation slash and litter management applied to acacia (legacy effects) on E. pellita growth; (iii) assess the long term changes in the top soil layer arising from above; (iv) evaluate, through a network of experiments, across the landscape, the nature and extent of growth responses to additional phosphorus. This data was also used to explore some of the critical site and stand variables which determine the variations in productivity and responses to management. The current growth rates of E. pellita are lower than those achieved in A. mangium. The management-legacy effects by conserving site resources provides a sustainable base for the growth of E. pellita, but for further increase in productivity, additional management actions are necessary. Changes in soil pH, carbon, N and extractable P were relatively small after four rotations. Supply of P at planting gave wood volume gains at harvest, ranging from 16 to 66% across sites. The plinthite layer in the soil profile was related to productivity, with higher growth rates of E. pellita occurring when the plinthite was at deeper layers. There is much scope for increasing productivity per unit area in this landscape, and available knowledge can be synthesized into a package of best practices for application. Management should aim to improve the quality of inter-rotation management to ensure more than 90% survival, and fast growth rates during the first 2 years. We provide a framework for further research and for refining management to produce the much needed additional domestic wood supply for the local industry.

(2010). Sustainability of eucalypt plantations in Australia is failing. Australian Forestry: Vol. 73, No. 4, pp. 207-208.