Tree production technologies for the Philippines and tropical Australia

• Department of Environment and Natural Resources, Philippines
• Visayas State College of Agriculture, Philippines
• Department of Environment and Natural Resources, Philippines
• Philippine Council for Agriculture, Forestry and Natural Resources Research and Development, Philippines
• University of the Philippines at Los Banos, Philippines

Extensive logging in the Philippines over the last 40 years has caused rapid deforestation and a shortfall in the supply of timber for the domestic market. With demand increasing along with the population, the logging of natural forests will be unable to supply the country's requirements without eroding the native forest stock. In addition, widespread clearing of trees on slopes has led to rapid land degradation and costly siltation of waterways and dams.
Planting trees can help treat these problems. But valuable native forest species are difficult to propagate and hence have not yet been feasible for use in large scale plantings. Several introduced species have been planted but results are often poor unless the sites are chosen carefully.
The main use for timber in the Philippines is fuelwood. This project investigated fast-growing species that are suitable for fuelwood, as a first step towards establishing plantations to supply much of the country's timber requirements. Where tree growth was severely limited by degraded soils on the sites chosen for the plantations this aspect was also studied.
Australia has also lost forest cover in its tropical and sub-tropical areas and thus more plantation options were needed for these areas.

This project replaced ACIAR project FST/1992/008, which concluded in June 1996. It had arisen following requests for research support in forestry from the Philippines. The current project followed on from the earlier work and was designed to improve the productivity of planted trees in the Philippines and parts of tropical and subtropical Australia. It evaluated tree and shrub species on different sites to develop a better understanding of the soil and climate requirements of particular species or provenances. The project included research to improve diagnosis of the nutrient status of selected tree species and to devise ways of treating nutrient disorders that retard growth. It also developed management practices for cost-effective establishment and growth of planted trees and shrubs

The completed ACIAR project FST/1992/008 had tested Australian and native species at a range of sites in the Philippines but more detailed trials of the best-performing species were needed. Two-year testing took place, and data from this and from the previous trials were used to project timber yields and the costs of production.
At the same time, appropriate management practices for growing planted trees were tested, to help develop and demonstrate the best techniques for the particular species in use. As part of this process field-tests were undertaken of bare-rooted stock for community planting and of suitable potting mixtures.
As inadequate plant nutrition frequently causes low productivity, ways of identifying soil problems (such as trace element deficiencies or toxicities) by means of plant appearance, chemical analysis of foliage, or fertiliser trials were tested. Where the species being assessed for plantation suitability were capable of nitrogen fixation; the amount of nitrogen fixed was also measured. The progress of seedlings planted during the earlier project was used as an indicator of the effectiveness of root inoculation with symbiotic organisms (fungi or bacteria).
The detailed techniques to be used for most of this work had been tested and refined in project FST/1992/008.

The project worked successfully through a network of collaborators in both the Philippines and Australia.
Network interaction occurred through annual planning and review meetings and site visits. The successful networking of institutions has led to the free flow of information and skill sharing.
The Project developed ways to identify deficiencies/toxicities of trees through visual symptoms, chemical analyses of foliage, and fertiliser trials. Commercial companies have used the results to remedy severe nutritional problems in their plantations.
The nutrient status of the foliage of many of the exotic tree species growing well in the Philippines was measured as well as that of plants showing signs of nutrient deficiency. Some of the same trees growing well in Australia have also been sampled and this databank enables assessment of the nutrient status of other planted trees. The 'yellow mangium' syndrome common through Southeast Asia can now be explained in terms of nutrient deficiencies.
Australian project staff worked with communities to improve the performance of a failed planting of 13,000 hectares established under a loan from the Asian Development Bank for the Philippine Forest Development Project Ilocos Norte. In much of the site the trees, mainly Eucalyptus camaldulensis, had grown very little in the 12 years since planting. The researchers found this was due to toxicity of nickel and chromium, which accumulated in the leaves at about 10 times the concentration found in normally growing plants
Spectacular growth was achieved in on-farm trials and in plantations (more than 20 metres in 4.5 years), with tree thinnings being harvested for cash and personal use by three years. The project sites are being maintained by the local government authorities and will continue to serve as a living record of the growth potential of different species.
The project has introduced nursery techniques for growing Australian hardwood species being introduced into the Philippines. This involved the development of new potting media, development of root training techniques using copper based paints, selection of micro symbionts, and appropriate fertilising regimes.
Philippine- and Australian-based root symbiont work focused on the mass production of endomycorrhiza and ectomycorrhiza strains. The effectiveness of five different strains was tested on a range of Acacia and Eucalyptus species, in the glasshouse and in the field. Rhizobium strains for the acacias had been selected and field tested in the earlier project and were routinely used in the nursery in the Philippines. The 15N natural abundance technique for measuring N fixation was shown to be useful for field-grown trees and a comprehensive review of the technique published.
The project showed that pasture lands in Australia cleared of trees many years previously had only very small populations of the beneficial ectomycorrhiza root fungi (ECM) propagules, which enhance the growth of trees planted as part of a reforestation program. For such sites, formation of ECM in the nursery is likely to have a beneficial effect on performance after outplant.
One of the initiatives of the project was to establish interactions with five community groups, three in Leyte, two in Cebu and one in Luzon. In each case local farmers indicated that they wished to plant trees identified by the project as being fast growing and suitable for the particular location and end use. Project collaborators provided technical advice, and seed was supplied by the project for site x species evaluation of on-farm trials.