Stephen J. Leisz

The Demise of Swidden in Southeast Asia? Local Realities and Regional Ambiguities

Abstract Swidden farmers throughout Southeast Asia are rapidly abandoning traditional land use practices. While these changes have been quantified in numerous local areas, no reliable region-wide data have been produced. In this article we discuss three linked issues that account for at least some of this knowledge gap. First, swidden is a diverse, complex, and dynamic land use that data gatherers find difficult to see, define and measure, and therefore often relegate to a “residual category” of land use. Second, swidden is a smallholder category, and government authorities find it difficult to quantify what is happening in many dynamic and varied smallholdings. Third, national policies in all countries of Southeast Asia have tried to outlaw swidden farming and to encourage swiddeners to adopt permanent agriculture land use practices. Drawing on specific, local examples from throughout the region to illustrate these points, we argue that an accurate assessment of the scale and pace of changes in swidden farming on a regional level is critically important for identifying the processes that account for these shifts, as well as evaluating their consequences, locally and regionally.

Carbon outcomes of major land‐cover transitions in SE Asia: great uncertainties and REDD+ policy implications

Policy makers across the tropics propose that carbon finance could provide incentives for forest frontier communities to transition away from swidden agriculture (slash-and-burn or shifting cultivation) to other systems that potentially reduce emissions and/or increase carbon sequestration. However, there is little certainty regarding the carbon outcomes of many key land-use transitions at the center of current policy debates. Our meta-analysis of over 250 studies reporting above- and below-ground carbon estimates for different land-use types indicates great uncertainty in the net total ecosystem carbon changes that can be expected from many transitions, including the replacement of various types of swidden agriculture with oil palm, rubber, or some other types of agroforestry systems. These transitions are underway throughout Southeast Asia, and are at the heart of REDD+ debates. Exceptions of unambiguous carbon outcomes are the abandonment of any type of agriculture to allow forest regeneration (a certain positive carbon outcome) and expansion of agriculture into mature forest (a certain negative carbon outcome). With respect to swiddening, our meta-analysis supports a reassessment of policies that encourage land-cover conversion away from these [especially long-fallow] systems to other more cash-crop-oriented systems producing ambiguous carbon stock changes - including oil palm and rubber. In some instances, lengthening fallow periods of an existing swidden system may produce substantial carbon benefits, as would conversion from intensely cultivated lands to high-biomass plantations and some other types of agroforestry. More field studies are needed to provide better data of above- and below-ground carbon stocks before informed recommendations or policy decisions can be made regarding which land-use regimes optimize or increase carbon sequestration. As some transitions may negatively impact other ecosystem services, food security, and local livelihoods, the entire carbon and noncarbon benefit stream should also be taken into account before prescribing transitions with ambiguous carbon benefits.

Geospatial revolution and remote sensing LiDAR in Mesoamerican archaeology

The application of light detection and ranging (LiDAR), a laser-based remote-sensing technology that is capable of penetrating overlying vegetation and forest canopies, is generating a fundamental shift in Mesoamerican archaeology and has the potential to transform research in forested areas world-wide. Much as radiocarbon dating that half a century ago moved archaeology forward by grounding archaeological remains in time, LiDAR is proving to be a catalyst for an improved spatial understanding of the past. With LiDAR, ancient societies can be contextualized within a fully defined landscape. Interpretations about the scale and organization of densely forested sites no longer are constrained by sample size, as they were when mapping required laborious on-ground survey. The ability to articulate ancient landscapes fully permits a better understanding of the complexity of ancient Mesoamerican urbanism and also aids in modern conservation efforts. The importance of this geospatial innovation is demonstrated with newly acquired LiDAR data from the archaeological sites of Caracol, Cayo, Belize and Angamuco, Michoacán, Mexico. These data illustrate the potential of technology to act as a catalytic enabler of rapid transformational change in archaeological research and interpretation and also underscore the value of on-the-ground archaeological investigation in validating and contextualizing results.

EFFECTS OF SWIDDEN CULTIVATION, STATE POLICIES, AND CUSTOMARY INSTITUTIONS ON LAND COVER IN A HANI VILLAGE, YUNNAN, CHINA

A study of air photographs and satellite imagery of a Hani village (Mengsong) in southwestern Yunnan between 1965 and 1993 showed that swidden cultivation did not lead to permanent conversion of forest land to agriculture but rather a conversion of a fairly homogeneous secondary closed-canopy forest into a highly heterogeneous land cover of different stages of forest succession. An analysis showed a direct correlation between government policies on producing food from hilly lands and the destruction of forest cover. This analysis also showed that since the Household Responsibility System was introduced in late 1979, allowing farmers the right to decide where, what, and how much to plant, farmers have decreased the amount of land farmed and intensified their farming methods.

Agent‐based modelling of shifting cultivation field patterns, Vietnam

Shifting cultivation in the Nghe An Province of Vietnams Northern Mountain Region produces a characteristic land‐cover pattern of small and larger fields. The pattern is the result of farmers cultivating either individually or in spatially clustered groups. Using spatially explicit agent‐based modelling, and relying on empirical data from fieldwork and observations for parameterization of variables, the level of clustering in agricultural fields observed around a study village is reproduced. Agents in the model act to maximize labour productivity, which is based on potential yield and labour costs associated with fencing of fields, and are faced with physical constraints. The simulation results are compared with land‐cover data obtained from remote sensing. Comparisons are made on patterns as detected visually and using the mean nearest‐neighbour ratio. Baseline simulation outputs show high degrees of spatial clustering and similarity to the land‐cover data, but also a need for further calibration of model variables and controls.

Using Traditional Swidden Agriculture to Enhance Rural Livelihoods in Vietnam's Uplands

Abstract Research in Vietnams uplands shows that poverty alleviation and environmental protection can be most readily achieved by communities building, protecting, and using their own assets more effectively. This approach starts by looking at what poor people already have, not what they lack. By contrast, government development policies often seek to modernize the rural sector through the introduction of new agricultural technology and improved marketing without taking existing local capacities into account. Such policies often fail to achieve their objectives. Traditional composite swidden agriculture (CSA), by contrast, may be more environmentally sustainable and better able to enhance household food security than many “modern” agricultural systems. Therefore, improvement of existing systems of composite swiddening in combination with adoption of new ventures, such as cattle raising, may achieve greater success than attempts to replace swidden agriculture with completely new “modern” farming systems.

Shifting Cultivation Without Deforestation: A Case Study in the Mountains of Northwestern Vietnam

To assess the role of shifting cultivation as a driving force of land cover change we examined the social, cultural, economic, and spatial dynamics of land use in a Vietnamese village. Instead of the denuded landscapes associated with shifting cultivation, the landscape of Tat hamlet is composed of a heterogeneous mosaic of fields, pastures, and forest patches in various stages of secondary succession. Failure to see secondary forests, let al.one the benefits of secondary forests, has led to government policies encouraging permanent agriculture — most of which have failed. Failure to account for the effects of landscape heterogeneity also means that significant effects of land cover change are not being recognized.

Geodetic imaging: A new tool for Mesoamerican archaeology

On 15 May 2012, Honduran President Porfirio Lobo convened a press conference to announce that researchers mapping areas of the Mosquitia region of Honduras, using airborne light detection and ranging (lidar), had discovered what appeared to be an extensive complex of archaeological ruins hidden beneath the dense canopy of rain forest that shrouds the terrain [UTL Scientific, LLC, 2012]. President Lobo released preliminary images of the ruins derived from the airborne lidar observations (Figure 1a) but withheld information about their precise location so that measures could be taken to protect and preserve this newly discovered cultural heritage. The coordinates of the ruins, determined from the lidar observations with an accuracy of a few decimeters, will enable archaeological teams to use the Global Positioning System to navigate through the dense forest directly to features of interest.

Mapping fallow lands in Vietnam's north-central mountains using yearly Landsat imagery and a land-cover succession model

The objective of this article is to investigate whether it is possible to use Landsat data together with ancillary data and temporal context to accurately identify land covers found in the fallow areas of Montane Mainland Southeast Asias (MMSEAs) difficult-to-map swidden landscapes. A rule-based non-parametric hybrid classification method that integrates knowledge about the vegetation regrowth patterns in these landscapes with analysis of Landsat imagery is developed. The method is applied to three upland districts of the Nghe An Province, Vietnam. The results show that the hybrid classification approach, with an overall accuracy of 90%, is superior to using a traditional maximum likelihood classifier, which generated an overall accuracy of 68%. The hybrid classification results indicate that the landscape is dominated by bush and bamboo, while the maximum likelihood classification suggests a landscape that is predominantly grass covered. The hybrid classification results are in agreement with local knowledge and information from fieldwork-based reports and articles on swidden systems in the study area and other parts of MMSEA.

Identifying Ancient Settlement Patterns through LiDAR in the Mosquitia Region of Honduras

The Mosquitia ecosystem of Honduras occupies the fulcrum between the American continents and as such constitutes a critical region for understanding past patterns of socio-political development and interaction. Heavy vegetation, rugged topography, and remoteness have limited scientific investigation. This paper presents prehistoric patterns of settlement and landuse for a critical valley within the Mosquitia derived from airborne LiDAR scanning and field investigation. We show that (i) though today the valley is a wilderness it was densely inhabited in the past; (ii) that this population was organized into a three-tiered system composed of 19 settlements dominated by a city; and, (iii) that this occupation was embedded within a human engineered landscape. We also add to a growing body of literature that demonstrates the utility of LiDAR as means for rapid cultural assessments in undocumented regions for analysis and conservation. Our ultimate hope is for our work to promote protections to safeguard the unique and critically endangered Mosquitia ecosystem and other similar areas in need of preservation.