Tree establishment technologies in the Philippines

• Visayas State College of Agriculture, Philippines
• Ecosystems Research and Development Services, Philippines
• Bukidnon Forests Inc, Philippines
• Department of Environment and Natural Resources, Philippines
• Department of Forest Biological Sciences, Philippines
• University of Queensland, Australia

Forest cover in the Philippines has been reduced by about half since 1950, confronting the country with some major problems. These include shortages of timber and fuelwood, and increased erosion leading to reduced soil fertility on sloping land, silting of major dams and rivers, and an increase in the incidence of severe flooding.

Recognising the seriousness of the problem, the Philippines government has given high priority to tree planting - so much so that reforestation is now one of the main activities of its Department of the Environment and Natural Resources (DENR). An estimated 6 million ha of degraded upland are considered suitable for reforestation, which is being pursued through encouragement of large commercial plantations, large plantings by the DENR itself, subsidies for tree establishment by smallholders, and promotion of agroforestry development by farmers.

The effectiveness of reforestation efforts has, however, been limited by a lack of information on the most suitable trees for particular areas, poor tree growth in nurseries, and low survival and growth rates after the trees are planted out. This project, which originated with a request from DENR to ACIAR for research collaboration in its reforestation program, will address each of those issues.

Specific objectives of the project are to:

. evaluate species and provenances of trees and shrubs for forestry, fuelwood and agroforestry uses in the Philippines, comparing species of Australian origin with those available locally;

. develop appropriate establishment and cultural techniques for reforestation and agroforestry in the Philippines; and

. develop diagnostic criteria for evaluating the nutritional status of selected tree species, and develop appropriate ameliorative procedures.

Field trials will provide, across a range of environments, initial screening and evaluation of species selected - on the basis of experience in ACIAR trials elsewhere - as likely to be suitable. The trees' performance will be compared with that of species now used locally. Further trials will evaluate performance within promising species, with the aim of identifying the most productive provenances.

Research to improve tree establishment - on rooting mixtures, size and form of container, fertiliser additions, hardening-off protocols and microbial inoculation - will be conducted at major nurseries in three regions. Work on nursery containers and hardening techniques will also be conducted at the University of Queensland. Planting out methods and timing will be investigated in the field, as will fertiliser regimes and weed control methods. On-farm trials will assess the agroforestry potential of various introduced species.

Work on nutrition will begin with field tests for soil deficiencies. Fertiliser requirements will be assessed, and solution and soil culture techniques will identify deficiency symptoms and assess critical nutrient levels. The possibility of using fertiliser to boost the initial slow growth of Acacia species will be examined at the University of Queensland, as will the tolerance of host species' rhizobia and mycorrhiza to soil acidity. The amount of nitrogen fixed by the trees will be estimated using a method developed under ACIAR PN 8800.

Results of the research will flow directly to user groups associated with DENR reforestation programs and to contract reforestation groups. Information on fuelwood potential will used by regional extension officers to develop recommendations for on-farm fuelwood production. Pulpwood plantation companies have expressed interest in conducting collaborative trials and making use of the project research results.

As improved management techniques have the potential to double tree growth rates, the project should produce substantial returns quite quickly. Farmers in the Philippines uplands will benefit, as will industrial plantations. For the community as a whole, the major benefits will be reduced run-off and flooding resulting from effective tree planting in catchment recharge areas.

Many of the research findings will be directly relevant to tree planting in northern Australia. The information acquired on growth rates and costs of production will allow improved assessment of returns on investment in tropical tree plantations in Australia.