Acacia crassicarpa : a tree in the domestication fast lane
Stephen Midgley
Portfolio Manager, Tree Improvement and Genetic Resources Program

The process of species' domestication provides the main theme for a substantial part of the work of CSIRO Forestry and Forest Products' Australian Tree Seed Centre (ATSC). Domestication is a broad process that covers work in areas including biogeography, environmental limitations, natural variation and propagation needs, selection and breeding, leading to some valuable social use. The ATSC is currently playing a role in the domestication process for more than 100 tree species. Some are well studied and domestication is relatively advanced (although well behind that for most agricultural crop plants) - Eucalyptus globulus, E. grandis, E. nitens, Melaleuca alternifolia, Pinus radiata and Acacia mangium are a few examples.Other species are less well known, and the domestication process proceeds at varying rates.

I recently had the opportunity to visit some commercial forest plantations on the island of Sumatra in Indonesia, and became acquainted with the expanding plantations of Acacia crassicarpa - a resource for the pulp industry in the region and one of our targets for domestication. Over 40 000 ha of plantation have been established, primarily on highly organic soils that have a low pH and can be occasionally waterlogged. Whilst A. crassicarpa on these wetlands generally gives a lower mean annual increment (MAI) than A. mangium on dry land, it has a higher wood basic density and similar pulp yield, so the yield of pulp per hectare remains acceptable.

In its natural stands in north Queensland and Papua New Guinea (PNG), A. crassicarpa is a moderately large tree of up to 30 metres height. Its natural occurrence and apparent vigour on poorly drained, slightly elevated plateau of open grassland suggested to people such as Doug Boland and John Turnbull, who were examining the potential for lesser-known species, that it could have a broader use in the humid tropics.

In 1980 the species was of almost insignificant commercial importance from native forests, and was best known by botanists and ecologists and through its close association with its more glamorous cousins A. mangium, A. aulacocarpa and A. auriculiformis. ATSC made the first research seed collections of A. crassicarpa in north Queensland in 1981. Overseas collaborators in FAO and Danida (the Danish aid agency) shared an enthusiasm for the potential of tropical acacias as species for reforestation, and in 1982 supported John Turnbull, ATSC and partners at the PNG Forest Research Institute in completing collections in Australia and PNG. A number of major collections of a suite of tropical Acacia species followed over the next 10 years with support from both the Australian Agency for International Development (AusAID) and the Australian Centre for International Agricultural Research (ACIAR). Landowners and managers in Queensland and PNG were very supportive in this early exploratory work. The PNG Department of Forests (now the National Forest Service of PNG) supported the work and made the collections possible.

Interest in the species grew rapidly once high quality, source-identified seed was available from natural provenances. By 1990 the ATSC had sent out over 500 research seedlots, primarily to research partners in SE Asia and China, many of whom were CSIRO partners in ACIAR-supported initiatives. In 1991 and 1992 CSIRO, with Chinese collaborators, reported on research tests on the pulping and paper-making qualities of A. crassicarpa (and other species) grown in trials.

By 1993 the species had demonstrated excellent survival and vigor in trials across a range of sites in the humid tropics, and was recorded by the Consultative Group for Research and Development of Acacias (COGREDA) as the third most important tropical acacia in SE Asia. Its suitability for peaty soils and the superiority of the PNG provenances had been demonstrated. The ongoing interest in the species, and the positive results from a wide body of research, prompted Lex Thomson to complete an annotated bibliography for the species in 1994. Maurice McDonald began a taxonomic assessment of A. crassicarpa and its close relatives at that time, and this was completed earlier in 2000. More recently, molecular studies of genetic diversity were completed by scientists at University Putra Malaysia and seed orchards established with CSIRO research partners in Vietnam and the Philippines.

It has been a short 15 years since the first species/provenance trials of A. crassicarpa were established. In that time the natural variation within the species has been assessed, breeding programs established, molecular marker technologies established, taxonomy clarified, silvicultural studies completed and wood and fibre properties assessed. Such rapid progress in the domestication of a tree species is remarkable.

Acacia crassicarpa plantations in Sumatra, Indonesia (courtesy of PT Arara Abadi, Indonesia)

Based on current world prices for Kraft pulp, the 40 000 ha plantation resource of A. crassicarpa on Sumatra represents an asset worth more than a billion dollars (US) to Indonesia. It is offering opportunities for employment and economic development for many Indonesians, and industrial opportunities for larger companies. The plantations reflect a great deal of collaborative work between many scientists and managers in many companies and research institutes and CSIRO. Organisations such as ACIAR, AusAID, Danida and FAO can justifiably be pleased with the results of their support to Asian research partners, partners in PNG and CSIRO, and with the close scientific relationships this has fostered.

For further information, contact: Stephen Midgley, E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.