SUSTAINABLE RESOURCE MANAGEMENT IN TROPICAL WATERSHEDS:

 Abstracts and excerpts from selected publications



MIXED TREE-VEGETATIVE BARRIER DESIGNS: EXPERIENCES FROM PROJECT WORKS IN NORTHERN VIETNAM

A. FAHLÉN1

1 Department of Physical Geography and Quaternary Geology,
Stockholm University,
S-106 91 Stockholm,
Sweden.

Land Degradation Develop. 13: 307-329, (2002)

ABSTRACT

There has been an increased interest in the use of vegetative barriers in acid-infertile upland management systems in Southeast Asia. This paper analyses the experimental designs and policies in early 1990s of using vetiver grass barriers (Vetiveria zizanioides L.) in micro-watersheds with short-rotation tree plantations in Vinh Phu Province, Vietnam. Four different mixed tree-vetiver models on degraded Ferric-Plinthic Acrisols are discussed. It is concluded that the institutional approach of demonstrating vetiver barriers as a model had a poor cost-wise performance, and that the model itself did not address the underlying issues of land degradation due to uncontrolled harvest of organic matter from the forest floors. The institutional approach was tainted with price distortions and 'disbursement-oriented' actions. Alternative and more flexible on-farm approaches, using V. zizanioides or the indigenous leguminous shrub Tephrosia candida (Roxb.) D.C. as vegetative barriers, were found to be more cost-effective and likely to have a higher rate of adoption among farmers. The institutional changes in land allocation policies (securing long-term usufruct users and transfer rights of agricultural and forest land) that took place in Vietnam in the early 1990s, in combination with a reorientation of programme policies to support needs of individuals and farmers' households, are hypothesised to have contributed more to the 're-greening' of the hills, than any single approaches of technical barrier designs by the Swedish-Vietnamese Forestry Co-Operation Programme in northern Vietnam.

KEY WORDS: land degradation, Vietnam; Vetiveria zizanioides L.; Tephrosia candida; micro-watershed; soil and water conservation; vegetative barriers

CONTRASTING VIEWS ON THE VALUATION OF TROPICAL FOREST RESOURCES

A. FAHLÉN1

1 Department of Physical Geography and Quaternary Geology, Stockholm University,
S-106 91 Stockholm,
Sweden.

EDSU Working Paper No. 41. 2001. Revised edition.

ABSTRACT

This paper discusses contrasting views on valuation methodologies used to assess impacts of changes in tropical forest resource use with particular reference to the uplands of Cambodia, Lao PDR, Philippines and Vietnam in Southeast Asia. Mainstream economic valuation techniques have recently been developed to be used as guiding instruments in decision-making of the optimal balances between nature-for-money conversions to yield monetary growth and ecosystem maintenance needs. Monetary-based valuation instruments have been used to identify that the development of markets and institutions that could value benefits from carbon sequestration capacity in tropical forests is a more promising step forward than to build conservation incentives from e.g. bioprospecting research and development benefits. Results from studies of the values of Non-Timber Forest Products (NTFP) are not consistent, problems with data acquisition are numerous and inconsistencies in applied methodology make it difficult to compare results (Godoy and Bawa, 1993). However, the surveys done by economists and ethnobotanists working on village levels have indicated that forest resources (both timber and non-timber assets) play an important role in subsistence household and village economies in rural areas (Kant, 1997). New drugs developed from NTFPs within the pharmacognosy industry represent large corporate benefits if immaterial property rights are included. On the other side, the local monetary value of the same resources are reported to be small, not substantially contributing to the land manager's willingness to conserve biodiversity (Mendelsohn and Balick, 1995). Mainstream resource economic theory, built around the discounted stream of monetary-based costs and benefits, has lately been challenged from both within and outside the centre of economic thinking. Odum (1996) and Darwin et al. (1996) have presented utilitarian valuation methodologies including multiple scales of causes and effects related to deforestation and tropical biodiversity reduction, and arguing that mainstream economic valuation techniques do not reflect the importance of limiting physical scale and distribution. Ecosystem-based viewers like Folke et al. (1994) have made contributions by identifying the importance of key species regulating essential life-support capacity in ecosystems. This school of ecosystem-based analysts is focusing on the resilience capacity of ecosystems and thus rank losses of ecosystem function as more severe than extinction of single individual species or genes per se. Another school of evaluators is increasingly concerned about the ethical, moral and cultural values that indigenous peoples' traditional skills and knowledge in sustainable forest management represent (Sharma, 1999). Bulte and Van Kooten identified the need for a safe minimum standard rather than preservation based on economic grounds. Brown (1994) added that cultural and social preferences of forest valuation among different interest groups have to be incorporated into the economic valuation approach. This author contributes with case studies that exemplify increasing resource competition between local and external stakeholders, and examples that illustrate that rational economic valuation principles are frequently sidestepped in the uplands of Southeast Asia due to collusive and corrupt chains of logging, wood processing and international trade. Therefore, the importance of building institutions that legitimate and secure local governance of resources, including capacity to resolve resource conflicts between actors, is recognised as a first step towards sustainable forest management in the uplands of Southeast Asia. Research has recently identified cases demonstrating that if local people are legitimated to develop self-organised institutions, they can effectively manage sustainable resource systems (Ostrom, 1999). Such a strategy could combine utilitarian use and non-use values for local peoples' livelihood as well as contribute with global ecosystem values. The issues are constrained and restricted by a time stamp, as several Southeast Asian countries are estimated to be effectively logged out within the next 5 to 30 years.

EROSION PROCESSES AND SOIL AND WATER CONSERVATION IN THE TROPICS:
A STATE OF THE ART REVIEW.

A. FAHLÉN1

1 Department of Physical Geography and Quaternary Geology, Stockholm University,
S-106 91 Stockholm,
Sweden.

EDSU Occasional Paper No. 5. Revised Edition. 2001.

INTRODUCTION

The magnitude of land degradation processes

Land degradation is as ancient as the processes of denudation of landscape surfaces1, chaotic natural events (e.g. volcanic disruptions), and the redistribution of soil constituents by rain splash energy and moving shear forces of water and wind. Thus, natural rates of erosion are ruled by geological and climatic processes, in combination with temporal and spatial distribution of vegetative cover and biological feedback loops.

Human-induced land degradation is at least known to have existed for several thousands of years (Jacobsen and Adams, 1958). Since the scale and effects of human-induced land degradation are an aggregated result of world population growth, increases in economic activity, and man-made land use changes over time, it is reasonable to assume that the problem has been magnified in modern times. However, there is surprisingly little validated information at the global scale of risks and rates of human-induced land degradation. The Global Assessment of Land Degradation (GLASOD) made a first attempt in 1990 to summarise the vulnerability of land resources in sub-humid, semi-arid, and arid zones, to human-induced water and wind erosion (Middelton and Thomas, 1997). According to this study, 8.3% of the total susceptible dryland areas classified (46 million km2) are degraded, from low to very high rates of impacts, due to human-induced water erosion, and 13.2% experience accelerated wind erosion. Reich et al. (1999), used population density in combination with soil and climatic attributes, as proxies of the vulnerability of water and wind erosion at the global scale. They found that the relative distribution of high to very high erosion vulnerability classes of land are frequent in poorer countries in the South, dominant between e.g. the southern frontier zone of the Sahara and the humid zone in Africa, and thus being areas at risk of facing significantly reduced food security. Further, Reich et al. (1999) and UNEP (1999) found that much of total estimated soil loss caused by water erosion on arable land originates from areas in the inter-tropical zones having fragile ecosystems, high population densities and high financial debts, and low-input land management technology.

The Global Environment Outlook (GEO-2000), by UNEP (1999), gives some qualitative data on changes in deforestation rates at the global scale. Some 80% of original forest cover2 has been affected by man-made impacts (WRI, 1997), and 56 million ha of forests were lost (mainly in tropical and subtropical zones) during the 1990 to 1995 period alone (UNEP, 1999). The report indicates that human-induced forest degradation at the global scale now has an increasing share of total land degradation processes caused by man (including altered feedback loops between the terrestrial/land/atmosphere interfaces).

At the regional scale, the International Food Policy Research Institute concluded in their year 2020 vision report that land degradation may cause 'hot spots' due to food deficits, trade deficits, and malnutrition in Central America, forest margin areas of the lower Amazon Basin, northeast India, Bangladesh and Myanmar, East and West Africa, semi-arid zones of Africa, West Asia, Southeast Asia, and periurban areas around major cities in the South (IPFRI, 1999).

Scale-related issues of concern

The consequences of ongoing rates of human-induced land degradation are real and significant. However, land degradation assessments are confronted with the need of improved validation methodologies at multiple scales, including improved predictions of interrelated effects as well as the need to account for new sources of human-induced impacts. At present, scale-related differences in assessment methodologies will yield highly contrasting results of the magnitude and importance of the problem. Present large-scale assessments based on coarse grid cell resolutions, e.g. CGMs, do not accurately describe effects, due to land use changes, of important biogeochemical processes at the micro- and watershed scales, like soil fertility changes, e.g. soil nutrient immobilising reactions, and changes in tropical hill slope hydrology, e.g. water vapour transfer between tree roots in deeper soil layers and the atmosphere. On the other hand, in situ sampling methodologies, e.g. soil conductivity measurements, at the micro-scale do not capture water flow processes at the watershed scale, e.g. soil macro-pore networks created by tree root growth (Bonell, 1998).

The multidisciplinary of land degradation analysis

The geomorphologist may find the explanation that land degradation has a 'high and long-lasting background level' in humid tropical zones as fully sufficient as vulnerable Tertiary and Quaternary deposits are exposed to present-day climate and economic activities. The agronomist tends to focus on interrelated effects of land degradation on crop productivity at the micro- and field-scales. Social-oriented scientists, on the other hand, generally place human-induced impacts and institutional arrangements as their prime overlay in any land degradation analysis. Economists have a keen interest by discipline to convert prime data on changes in land resources into a temporary stream of monetary and discounted costs and benefits (often in combination with a reiteration of prime data from micro-scale to national or larger scales). The present methodology of bringing multiple views together piece-by-piece is increasingly unsatisfactory as it is realized that prime data is frequently either of poor quality or unconsciously transferred between different scales and disciplines without proper validation.

Nevertheless, human-induced land degradation analysis is a multidisciplinary subject and has to develop an integrated approach including a multiple of scales, impacts, stakeholders, and expert disciplines3. New directions in multidisciplinary land degradation analysis include the identification and recognition of asymmetrical links (physiographical, economic, institutional, and ecological) between e.g. affected headwater areas and off-site downstream areas at the watershed and larger scales. Recent development in software-based natural resource management systems, like WaterWare (Environmental Software and Services GmbH, 1999), provides technology that can bring multiple data and views into a comprehensive format.

Albeit such advancements, the development of sustainable land management systems is still crucially dependent on the effective engagement of local land users in the planning and implementation of soil and water conservation projects, watershed management, etc. During the 1990s, local participation and strengthened local governance of land and water resources started to be commonly viewed as essential (but not sufficient) ingredients to yield success in any multi-client affairs of land degradation.

The evolution of soil loss-yield-time predictions

Soil erosion researchers have traditionally devoted their interest to study and quantify rates of soil loss and runoff under various local climate-land-water regimes. During the 1980s and beyond a substantial shift in erosion research objectives has occurred. It is now widely accepted that more attention should be directed to qualitative assessments of effects of land degradation (e.g. soil loss-yield-time predictions). The development of process-based and fundamental mathematical relationships of erosion processes during the last decades has promises to move beyond the limitations given by empirical prediction formulas. Likewise, it is increasingly important to scientifically address and validate the interrelated effects and feedback mechanisms caused by deforestation and biodiversity loss on land capability.

Any transfer of erosion prediction technology from North to South has to be accompanied with a judicious verification of results and comprehensiveness. A specific problem, recently identified, occurs when empirical concepts based on long-term average climate data is applied in environments dominated by chaotic and event-based rainfall patterns. In the future it is likely that modelling of rainfall erosivity instead will be based on energy flux density (ASAE, 1995).

Notes on this publication

It is the author's belief that researchers and planners in the South are frequently hampered to get on-line to the computerized and well-informed research society in the North. An operating linkage where ideas can be exchanged from one country to another - concerning successes and failures in soil conservation, about research methodology and applied technology, socioeconomics, etc. - seems to be of major importance. Though just another piece of text, this review supports the idea of a visual exchange-office where soil and water conservation measures and research methodologies can be looked at as the sum of cumulative human efforts in regions with different ecological, political and economic conditions between themselves. The reader must ultimately judge what may be transferable from one place to another and what cannot be.

It is felt that the ongoing and multilingual debate among researchers in the important fields outlined above, is fundamental as to allow for a wider social and economic attraction of sustainable land management among decision-makers and stakeholders.

Acknowledgement

A previous version of this text was prepared by financial support from the Departments of Human and Physical Geography, Stockholm university, which is here acknowledged. Professor Carl Christiansson and Dr. Peter Schlyter, Dept. of Physical Geography, Stockholm university, have both contributed with constructive criticism and valuable improvements of an earlier draft. Participants at various national/international courses at Stockholm university, Stockholm, and Swedish University of Agricultural Sciences, Uppsala, have also made important comments which are here gratefully acknowledged.

Any remaining faults and imperfections are solely the responsibility of the author.

References

ASAE. 1995. Abstract of ASAE paper 95-378. URL:http//asae.org/mtgs/am95/events/abstract/ 378.html. The Internet.

Bonell, M. 1998. Possible Impacts of Climate Variability and Change on Tropical Forest Hydrology. Climatic Change 39:215-272.

Brookfield, M.E. 1993. Miocene to Holocene uplift and sedimentation in the Northwestern Himalaya and Adjacent Areas. Schroeder, J.,F., Jr. (ed.). Himalya to the Sea. Routledge, London and New York. pp. 43-71.

Environmental Services and Software GmbH. 1999. WaterWare: A Water Resources Management Information System. URL: http://www.ess.co.at/ WATERWARE/. The Internet.

Hurni, H. 1997. Concepts of sustainable land management. Special Issue: Geo-Information for Sustainable Land Management (SLM). ITC-Journal. 1997, No. 3-4, 210-215.

IFPRI. 1999. Backgrounder: "Hot Spots" of Erosion, Pollution, Deforestation and Other Land Degradation Hit Poor Areas Hardest, Threatening Food Supplies and Increasing Poverty. URL:http://www.cigar/org/ ifpri/2020/backgrnd/land.htm

Jacobsen, T., and Adams, R.M. 1958. Salt and Silt in Ancient Mesopotamian Agriculture. Science, Vol.128 (3334):1251-1258.

Middleton, N., and Thomas, D. 1997. World Atlas of Desertification. Published for Unesco by Arnold Publ. 2nd edition. London.

Reich, P., Eswaran, H., and Beinroth, F. 1999. Global Dimesions of Vulnerability to Wind and Water Erosion.URL:http://www.nhq.nrcs.usda.gov/WSR/ Landdeg/papers1/ersnpaper.html. The Internet.

UNEP. 1999. Global Environmental Outlook (GEO-2000). URL: http//www.unep.org/geo2000/ english/0043-0046.htm. The Internet.

1 for example, Brookfield (1993) estimated that an average width of 150 km has been eroded from the southern front zone of the Himalayas since the Miocene due to fluvial processes

2 estimated forest cover some 8 000 years before significant human impacts occurred and assuming present climate

3 Hurni (1997) identified a 'multi-level stakeholders approach' as to achieve sustainable land management



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