Fungi help Chinese trees stand tall
Firewood is so scarce, explained Professor Dell, that every twig and branch is precious. "Everything that falls onto the ground is picked up," he said.Appreciating the harshness of life in parts of China helps put in perspective the significance of the work being done by Murdoch University to improve the productivity of eucalypt trees in China.Professor Dell, professor of plant science at Murdoch's School of Biological Sciences, has been working on eucalypt productivity in China for the past seven years, mainly in Yunnan Province in south west China and in Guangdong Province in southern China.The project is being carried out in collaboration with the Commonwealth Scientific Industrial Research Organisation (CSIRO) Forestry and Forest Products. It is funded by the Australian Centre for International Agricultural Research (ACIAR), which uses Australian aid money to promote agriculturally-based projects in developing countries using Australian expertise.Expertise in eucalypt forest management is one area in which Murdoch has established a reputation. Murdoch University was specifically sought out by the Chinese to help with their eucalypt productivity levels.Eucalypt forests are prevalent in southern China and there are plans to increase this forest area to up to one million hectares by the year 2000. Compare the size of this with the total area of hardwood plantations in Australia which is estimated at only about 159,000 hectares. However Chinese eucalypts are small compared with their international counterparts, yielding only 15 to 20 per cent of the world productivity average.Apart from its impact on the lives of ordinary villagers who depend on the trees for fuel and construction, low eucalypt productivity also has implications for industries relying on the tree, such as the Chinese eucalypt oil industry and timber industry and it impacts on plans to establish pulp mills, to produce products as basic as toilet paper.One of the main reasons for poor eucalypt productivity in China is the poor soils of the mountain scapes where the trees grow - the result of centuries of subsistence farming. Another reason is the lack of ectomycorrhizal fungi in Chinese soils -- and this is where Australian expertise is particularly relevant.Certain higher fungi, such as toadstools, puffballs, mushrooms and truffles, are known as ectomycorrhizal fungi. These fungi have a beneficial association with eucalypts, helping them to grow on infertile soil.
Ectomycorrhizal fungi grow in the soil as fine strands of hyphae, gathering water and nutrients, which are transferred to the tree. The fungus in fact acts like a pipeline for the tree, said Professor Dell.Research had shown that ectomychorrhizal fungi made a significant contribution to the biomass of forest ecosystems in terms of nutrient uptake and cycling, he said.The relationship between the fungi and trees is symbiotic because the fungi get carbon from the tree in return for supplying mineral nutrients and water.But not all ectomycorrhizal fungi are able to recognise and colonise eucalypt roots. Many native fungi in China evolved with northern hemisphere trees such as pines and oaks and do not form beneficial associations with eucalypts. The eucalypt ectomycorrhizal fungi have evolved with eucalypts in isolation in Australia.The challenge then, explained Professor Dell, was to establish Australian strains of ectomycorrhizal fungi in Chinese nurseries and then to transplant ectomycorrhizal seedlings into the eucalypt plantations.The team from CSIRO and Murdoch set up programs to select ectomycorrhizal fungi and then to inoculate eucalypt seedlings with them before outplanting into the field.An integral part of this program was ensuring good nursery management of the ectomycorrhizal-inoculated eucalypts. This included know-how on choice and preparation of potting mixes, type of containers, drainage and hygiene. The Australian team also oversaw the field trials of ectomycorrhizal-inoculated eucalypts and analysed the results. Other research focused on improving eucalypt productivity by remedying nutrient deficiencies in the soil with fertiliser application.Apart from affecting the growth of the trees directly, nutrient deficiency can also affect ectomycorrhizal development and tree response to inoculation, said Professor Dell.The end result of the field trials by the Australian team was bigger eucalypts,
by up to 50 per cent.It will be several years before China's eucalypt plantations begin to bear the fruit of Australian input but the promising results are already there for all to see."I've really enjoyed the work because we can see immediately the benefits of what we are doing," said Professor Dell."And it's a two-way thing, both sides have learnt from each other."The official ACIAR project ends this year but the team from CSIRO and Murdoch University have left a valuable legacy.Via workshops and manuals, staff on China's eucalypt plantations have been invested with the valuable know-how of improving the productivity of their trees via nutrient applications and ectomycorrhizal inoculation. They have been trained in all aspects of eucalypt management -- from identifying nutrient disorders to conducting field trials.According to Professor Dell there has been a blossoming of activity on the Chinese eucalypt plantations. The future looks bright in terms of improving the productivity of commercial plantations and the sector has earned kudos from Chinese government for the progress they have made.ACIAR's project funding of nearly $1.8 million ($300,000 of which went to Murdoch) has been spent well.But for Professor Dell, it is not just about research funding or commercial returns."It is always in the back of my mind, that image of old ladies walking miles and miles to collect leaves and twigs," he said."It's also about improving the living conditions for all those people and ensuring that trees can be grown sustainably for future generations."
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Associate Professor Bernie Dell School of Biological Sciences and Biotechnology Telephone (08) 9360 2875 email dell@central.murdoch.edu.au |
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