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[Anual Report 96 :
Table of Contents]

Plantation Forestry on Degraded
and Low-potential Sites

Alternative socio-economic approaches to reclaiming degraded lands in China are being applied to the joint problems of poverty and land degradation. The Chinese Academy of Forestry has produced several technological solutions for degraded lands, but now seeks appropriate socio-economic structures to efficiently achieve their wide-scale application. Degraded lands in mountainous and hilly regions account for 60 per cent of China's total land area and their populations have very low incomes. All levels of government in China aim to encourage productive use of degraded lands through popular participation in forestry: new rights and responsibilities on land given to State farm employees or free enterprise on lands re-allocated to farmers. Smallholder tree planting may offer solutions but there are concerns about the ecological, economic and social sustainability of tree planting on such lands.

Socio-economic surveys to evaluate existing production systems have been completed at five selected sites. Research at two other sites investigated the processes resulting in site deterioration and productivity decline (part of a CIFOR network of research sites in Asia and Africa.

West Kalimantan, Indonesia, is inhabited by farmers who practise shifting cultivation in forest margins and so contribute to the expansion of Imperata grasslands. One option to make these lands economically viable again is to cultivate crops which withstand low-input farming practices (fertilisation and tending). As a pioneer species on Imperata land, Vitex pubescens can be expected to grow in plantations, but cultivation methods and growth capacity of the species are largely unknown. CIFOR is testing Vitex pubescens tolerance for low-input cultivation practices, the economic returns to be expected from producing high-quality charcoal, and whether such tree plantations will be acceptable to smallholders.

Research on the catalytic effect of tree planting on the rehabilitation of forest biodiversity on degraded tropical lands is investigating: whether tree plantations can enhance biodiversity of indigenous and naturalised plant species; how management intensity and species selection affect re-colonisation by indigenous species within plantations; if tree plantations can restore faunal biodiversity; and how land-use practices, proximity to natural forest and degree of site degradation influence biodiversity within plantations. Field studies have been carried out in the Congo and South Africa. The former included observations on litter and soils, bird and mammal populations, and changes in soil fauna and micro-fauna. CIFOR's collaborators presented their work at a IUFRO-World Bank-USDA Forest Service workshop.

Site management and productivity in tropical forest plantations and the long-term impact on site productivity must be well understood and monitored if plantations as a land-use technology are to be sustainable. Do the changes in soil characteristics induced by intensive plantation management lead necessarily to site degradation? How can changes in soil characteristics be influenced by silvicultural and harvesting practices? Can successive, equally productive crops of trees be harvested from a site in perpetuity? A network of partnerships in Indonesia, Malaysia, Australia, Congo, China, India and South Africa is using a multi-site approach with a set of treatments common at all locations. Additional treatments are tailored to each site to maximise the value from this research to each specific region.

Dipterocarps are the most important family of tropical trees in Asia but most knowledge remains fragmented. The potential benefits of this family of trees have not been fully recognised. Thirteen leading scientists have contributed to an overview of the state of knowledge on Dipterocarps which identifies the main questions still to be answered. The book will be published in 1997.

Another multi-authored book produced in collaboration with CSIRO Division of Forestry and Forest Products will be published by ACIAR in early 1997. It will improve understanding of the role of nutrients and water, and their interaction, in problems of tree growing and of sustaining forest production in tropical and sub-tropical environments.

In the Amazonian forests 41.5 million hectares have been converted to other uses, 17.5 million hectares to pastures. About half of this area has become unproductive only a few years after establishment and is now abandoned land. In many instances, reforestation is the only way to restore these wastelands. Soils in these areas have been severely disturbed ­ low levels of organic matter and nutrients have become limiting factors. Tree species which could adapt to this new environment need to be found. Developing new tools to enhance species/site matching capabilities and to streamline the species and provenance testing process is a priority. In the Amazonian region, EMBRAPA and CIFOR are jointly adapting and testing a model, PLANTGRO, which predicts tree performance on untested sites using notional relationships between trees and site conditions, and soil and climate variables. A course was held for fifteen Brazilian collaborators (Manaus, June 1996) and data files were prepared for 25 plantation species (20 native and 5 exotic).

Tropical acacias are important for reforestation in South and South-east Asia where over one million hectares have already been planted. Recent reports suggest that productivity of some important species may be affected by fungal pathogens including leaf spot, shoot blight, stem canker, heart rot and gall rust. A series of disease surveys was undertaken in native Australian stands and trials, social forestry planting and large-scale industrial plantations in India, Indonesia, Malaysia and Thailand, to assess fungal pathogens as a potential threat to tropical acacia growth and productivity, and the relative importance of individual fungal pathogens. CIFOR's collaborators presented their results at a workshop in May 1996 at an Indonesian reforestation company in Sumatra. Following publication in 1997 of this benchmark in current knowledge of the pathology of the four most important acacia species currently grown in the region, CIFOR will undertake a second phase with support from ACIAR.

Principal Collaborators:
Australia: Australian National University (ANU), CSIRO Division of Forestry and Forest Products, Queensland Forestry Research Institute, Institute for Horticultural Development, Plant Soft Service;
Brazil: Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA);
Canada: International Development Research Centre (IDRC);
China: Chinese Academy of Forestry (CAF), Ministry of Forestry, Zhejiang Forestry College, Central-South Forestry University, Forestry Department of Central-China Agriculture University, Fujian Forestry College;
Congo: Centre National de Recherche Forestière (CNRF), Direction Générale de la Recherche Scientifique et Technique (DGRST), U.R.2P.I Pointe-Noire, Office de la Recherche Scientifique et Technique Outre-Mer (ORSTOM), University of Brazzaville;
France: Centre Nationale de la Recherche Scientifique (CNRS), INRA-Centre de Nancy Unité Ecosystèmes Forestiers, ORSTOM, Association Forêt-Cellulose (AFOCEL);
India: Kerala Forest Research Institute, French Institute of Pondicherry; Centre of Minor Forest Products;
Indonesia: Center for Agro-Socioeconomic Research (CASER), Yayasan Dian Tama - Pontianak, Tanjugpura University, Institut Pertanian Bogor, PT Musi Hutan Persada; Malaysia: Department of Forestry, Forest Research Institute Malaysia (FRIM);
Philippines: SEAMEO Regional Center for Graduate Study and Research in Agriculture; South Africa: Institute for Commercial Forestry Research;
Thailand: International Board for Soil Research and Management (IBSRAM), Royal Forestry Department;
UK: International Mycological Institute, Royal Botanic Garden Kew;
USA: USDA Forest Service, Southern Forest Experiment Station (Pineville), University of Massachusetts, Yale University.

CIFOR Project Team:
Christian Cossalter, Shigeo Kobayashi, John Turnbull, Allan Tiarks, Neil Byron