Sonya Dewi

Influence of coastal vegetation on the 2004 tsunami wave impact in west Aceh

In a tsunami event human casualties and infrastructure damage are determined predominantly by seaquake intensity and offshore properties. On land, wave energy is attenuated by gravitation (elevation) and friction (land cover). Tree belts have been promoted as “bioshields” against wave impact. However, given the lack of quantitative evidence of their performance in such extreme events, tree belts have been criticized for creating a false sense of security. This study used 180 transects perpendicular to over 100 km on the west coast of Aceh, Indonesia to analyze the influence of coastal vegetation, particularly cultivated trees, on the impact of the 2004 tsunami. Satellite imagery; land cover maps; land use characteristics; stem diameter, height, and planting density; and a literature review were used to develop a land cover roughness coefficient accounting for the resistance offered by different land uses to the wave advance. Applying a spatial generalized linear mixed model, we found that while distance to coast was the dominant determinant of impact (casualties and infrastructure damage), the existing coastal vegetation in front of settlements also significantly reduced casualties by an average of 5%. In contrast, dense vegetation behind villages endangered human lives and increased structural damage. Debris carried by the backwash may have contributed to these dissimilar effects of land cover. For sustainable and effective coastal risk management, location of settlements is essential, while the protective potential of coastal vegetation, as determined by its spatial arrangement, should be regarded as an important livelihood provider rather than just as a bioshield.

Reducing emissions from land use in Indonesia: motivation, policy instruments and expected funding streams

Land-based emissions of carbon dioxide derive from the interface of forest and agriculture. Emission estimates require harmonization across forest and non-forest data sources. Furthermore, emission reduction requires understanding of the linked causes and policy levers between agriculture and forestry. The institutional forestry traditions dominated the emergence of the discourse on Reducing Emissions from Deforestation and forest Degradation (REDD+) while more holistic perspectives on land-based emissions, including agriculture, found a home in international recognition for Nationally Appropriate Mitigation Actions (NAMAs). We tested the hypothesis that, at least for Indonesia, the NAMA framework provides opportunities to resolve issues that REDD+ alone cannot address. We reviewed progress on five major challenges identified in 2007 by the Indonesian Forest Climate Alliance: 1) scope and ‘forest’ definition; 2) ownership and tenurial rights; 3) multiplicity and interconnectedness of drivers; 4) peatland issues across forest and non-forest land categories; and 5) fairness and efficiency of benefit-distribution mechanisms across conservation, degradation and restoration phases of tree-cover transition. Results indicate that the two policy instruments developed in parallel with competition rather than synergy. Three of the REDD+ challenges can be resolved by treating REDD+ as a subset of the NAMA and national emission reduction plans for Indonesia. We conclude that two issues, rights and benefit distribution, remain a major challenge, and require progress on a motivational pyramid of policy and polycentric governance. National interest in retaining global palm oil exports gained priority over expectations of REDD forest rents. Genuine concerns over climate change motivate a small but influential part of the ongoing debate.

Segregate or Integrate for Multifunctionality and Sustained Change Through Rubber-Based Agroforestry in Indonesia and China

Rubber (Hevea brasiliensis L.) production systems have conserved forest biodiversity in some parts of Asia and are a threat elsewhere. A holistic view on these two sides of the coin is needed. The roles planted trees and agroforestry play in the transformation of lives and landscapes depend on the stage of “forest transition” and the spatial configuration, segregation or integration, of the landscape. “Forest transitions” need to be understood at the level of the actual pattern of change, (one level up) at the level of drivers of change, and (one level down) at the level of consequences for ecosystem goods and services. To close the loop on a feedback mechanism, forest transitions also need to be understood at the level of mechanisms that link desirable or undesirable consequences of changes in tree cover to the drivers, providing positive or negative feedback. “Forest ecosystem services” can be partially fulfilled by agroforests as a form of domesticated forest. We revisit the theoretical framing of agroforests as part of forest transition and discuss a case study of the rise and decline of complex rubber agroforests in lowland Sumatra (Indonesia) and the recent expansion of monoculture rubber in China replacing agroforestry systems. Both cases indicate a complex of driving and conditioning factors but also a current lack of incentives to reverse the trend toward landscape segregation. Complex agroforests represent an intermediate stage of intensification, between natural forest and home garden, and may occupy an intermediate stage in the way landscapes develop under the influence of land users and other stakeholders. Although complex agroforests represent considerable value (biodiversity and carbon stocks) of relevance to external stakeholders, incentive systems for the land users need to match these values; otherwise, these systems will disappear when more intensified and simplified tree crop systems take over. Current analysis of the choices in land sparing versus land sharing, and segregation versus integration, emphasizes the convex or concave nature of the bifunctional trade-off curves.

Mud, muddle and models in the knowledge value-chain to action on tropical peatland conservation

Tropical peatlands are known not only for their high, area-based, carbon emissions in response to land-use change but also as hot spots of debate about associated data uncertainties. Perspectives are still evolving on factors underlying the variability and uncertainty. Debate includes the ways of reducing emissions through rewetting, reforestation and agroforestry. A knowledge value-chain that is long and complex links (a) fundamental understanding of peat and peatland processes leading to sciencebased quantification and default values, (b) willingness and (c) ability to act towards emission reduction, and ultimately (d) to local, national and global actions that effectively provide rules, incentives and motivation to conserve peat and reduce emissions. We discuss this value chain, its stakeholders and issues that still remain partially unresolved. We conclude that, to shorten the denial and conspiracy-theory stages of debate that otherwise slow down steps B and C, networks of international and national scientists have to be involved at the early stage of identifying policysensitive environmental issues. Models span part of the knowledge value-chain but transition of analysis units requires specific attention, from soil volumes through area and commodity flows to opportunities for reductions. While drainage of peatlands triggers landscape-scale increases in emissions, factors beyond drainage depth, including nutrient supply, may have a major influence on decomposition rates. Attempts to disentangle the contributions of plant and peat-based respiration in surface flux measurements involve assumptions that cannot be easily verified in comparisons between land uses. With progress on A leading to new internationally accepted defaults and with resistance on step B reduced, the reality of C and lack of working solutions for D is currently constraining further progress.

Tropical forest-transition landscapes: a portfolio for studying people, tree crops and agro-ecological change in context

ABSTRACT Nudging the development trajectory of tropical landscapes towards sustainability requires a global commitment and policies that take diverse contexts and forest transitions into account. Out-scaling and upscaling landscape-level actions to achieve sustainable development goals globally need to be based on understanding of extrapolation domains and interconnectivity of products and services. We evaluated three portfolios of tropical landscape observatories and quantified extrapolation domains across ecological zones, stages of forest transition, human development index (HDI), population density and potential prominence of four dominant tropical tree crops (arabica coffee, cacao, rubber and oil palm). The ASB Partnership for Tropical Forest Margins portfolio was focussed on active humid forest margins and the Poverty and Environment Network on early stages of forest transition. The portfolio of sentinel landscapes of the Forests, Trees and Agroforestry (FTA) research programme provides a 5% sample of pantropical area, 8% of people, 9% of tree cover and 10–12% of potential tree crop presence, with quantified biases across zones, transition stages and HDI. In the ‘water tower’ configuration, relatively high population density coincides with biodiversity, coffee expansion and contested ecosystem services. The extrapolation domain of the FTA portfolio includes trade-off (tree loss) and synergy (restoration) phases of tropical forest transition. EDITED BY Paolo Omar Cerutti

Can intensification reduce emission intensity of biofuel through optimized fertilizer use? Theory and the case of oil palm in Indonesia

Closing yield gaps through higher fertilizer use increases direct greenhouse gas emissions but shares the burden over a larger production volume. Net greenhouse gas (GHG) footprints per unit product under agricultural intensification vary depending on the context, scale and accounting method. Life cycle analysis of footprints includes attributable emissions due to (i) land conversion (‘fixed cost’); (ii) external inputs used (‘variable cost’); (iii) crop production (‘agronomic efficiency’); and (iv) postharvest transport and processing (‘proportional’ cost). The interplay between fixed and variable costs results in a nuanced opportunity for intermediate levels of intensification to minimize footprints. The fertilizer level that minimizes the footprint may differ from the economic optimum. The optimization problem can be solved algebraically for quadratic crop fertilizer response equations. We applied this theory to data of palm oil production and fertilizer use from 23 plantations across the Indonesian production range. The current EU threshold requiring at least 35% emission saving for biofuel use can never be achieved by palm oil if produced: (i) on peat soils, or (ii) on mineral soils where the C debt due to conversion is larger than 20 Mg C ha−1, if the footprint is calculated using an emission ratio of N2O–N/N fertilizer of 4%. At current fertilizer price levels in Indonesia, the economically optimized N fertilizer rate is 344–394 kg N ha−1, while the reported mean N fertilizer rate is 141 kg N ha−1 yr−1 and rates of 74–277 kg N ha−1 would minimize footprints, for a N2O–N/N fertilizer ratio of 4–1%, respectively. At a C debt of 30 Mg C ha−1, these values are 200–310 kg N ha−1. Sustainable weighting of ecology and economics would require a higher fertilizer/yield price ratio, depending on C debt. Increasing production by higher fertilizer use from current 67% to 80% of attainable yields would not decrease footprints in current production conditions.

Palm oil expansion in tropical forest margins or sustainability of production? Focal issues of regulations and private standards

Palm oil expansion captures headlines, primarily out of concern that encroachment to tropical forest causes environmental problem and ignites social issues. Cascading ecological and social issues cause loss of trust, (threats of) consumer boycotts and multiple standards and certification responses. However, diverse sustainability issues should be taken into account within the issue-attention cycle. Most of current production (89%) occurs in SE Asia, with Indonesia in the lead. Peru and Cameroon are examples of current expansion elsewhere. In Indonesia two phases of new establishment of palm oil coexist within a forest transition gradient: (i) (industry-led) expansion into new forest margins with many social and ecological consequences; and (ii) (often farmer-led) conversion of existing agroforestry and tree crop (often rubber-based) or pasture economies in mosaic landscapes. External consumer concerns refer to the expansion phase, rather than to production sustainability or issues of smallholder concern. However, certification standards are only partially adjusted to the latter. After a ‘voluntary industry standards’ phase of differentiation with and shifting blame to non-certified others, government involvement in Malaysia and Indonesia suggests that standards and certification can trickle down to enforceable good practice standards for all. This leads to ineffective policies that does not address the real issues in local context. On the other hand, subnational jurisdictional entities are the scale at which oil palm production can be balanced with other goals, such as forest conservation and smallholder welfare.