Life cycle carbon emissions of different land conversion and woody biomass utilization scenarios in Indonesia

Scenario analysis of supply- and demand-side solutions for circular economy and climate change mitigation in the global building sector

Residential and non-residential buildings are a major contributor to human well-being. At the same time, buildings cause 30% of final energy use, 18% of greenhouse gas emissions (GHGE), and about 65% of material accumulation globally. With electrification and higher energy efficiency of buildings, material-related emissions gain relevance. The circular economy (CE) strategies, narrow, slow, and close, together with wooden buildings, can reduce material-related emissions. We provide a comprehensive set of building stock transformation scenarios for 10 world regions until 2060, using the resource efficiency climate change model of the stock-flow-service nexus and including the full CE spectrum plus wood-intensive buildings. The 2020-2050 global cumulative new construction ranges from 150 to 280 billion m2 for residential and 70-120 billion m2 for non-residential buildings. Ambitious CE reduces cumulative 2020-2050 primary material demand from 80 to 30 gigatons (Gt) for cement and from 35 to 15 Gt for steel. Lowering floor space demand by 1 m2 per capita leads to global savings of 800-2500 megatons (Mt) of cement, 300-1000 Mt of steel, and 3-10 Gt CO2-eq, depending on industry decarbonization and CE roll-out. Each additional Mt of structural timber leads to savings of 0.4-0.55 Mt of cement, 0.6-0.85 Mt of steel, and 0.8-1.8 Mt CO2-eq of system-wide GHGE. CE reduces 2020-2050 cumulative GHGE by up to 44%, where the highest contribution comes from the narrow CE strategies, that is, lower floorspace and lightweight buildings. Very low carbon emission trajectories are possible only when combining supply- and demand-side strategies. This article met the requirements for a gold-gold JIE data openness badge described at http://jie.click/badges.

Beyond biomass production: Enhancing biodiversity while capturing carbon in short rotation coppice poplar plantations

Biodiversity is essential for the functioning of ecosystems and the provision of services. In recent years, the role of plantations in mitigating climate change through carbon sequestration has been highlighted. In the Mediterranean area, high-density poplar plantations in short-rotation with resprouting management (SRC) have been established for biomass purposes on mostly irrigated agricultural land, coexisting with rainfed and irrigated agricultural crops. This study aims to assess the contribution of these plantations to this type of agroforest ecosystem in terms of biodiversity. For this purpose, both flora and fauna diversity were evaluated both within and outside of the plantation. Additionally, the accumulated carbon in the biomass, as well as in the accompanying vegetation within the plantation, was assessed. Different indices were used to evaluate both the intrinsic diversity of the forest plantation and the degree of substitution and complementarity between the different communities of the landscape. Our findings reveal distinct biodiversity patterns in the land-use scenarios sampled. Specifically, we observed significantly higher flora-species richness in SRC plantations than in the adjacent agricultural land, whereas fauna richness showed a similar but slightly higher level in the forested area. A moderate level of complementarity between land uses was found for insects and mammals (around 45 %), contrasting with high complementarity for birds (87 %) and flora (90 %). This suggests substantial turnover and replacement among these ecological environments. Our results indicate that a second rotation (4 year) plantation could accumulate a total of 61.6 Mg C ha-1, and even though adventitious flora represents <2 % of the total carbon accumulated, its importance in providing ecosystem services is considerable. Hence, these findings evidence the fact that SRC poplar plantations can enhance biodiversity in Mediterranean agroforest ecosystems and actively contribute to various provisioning ecosystem services, including carbon sequestration, reflecting a multi-objective approach that extends beyond biomass production.

Assessing the potential of poplar short rotation plantations to contribute to a low-carbon bioeconomy under water-limited conditions

Poplar short rotation coppice (SRC) systems are important for biomass production and for short-to medium-term carbon (C) sequestration, contributing to a low-carbon bioeconomy and thus helping to mitigate global warming. The productivity and profitability of these plantations are, however, challenged under restrictive irrigation associated with climate change. This study compares the above- and below-ground C sequestration potential and economic viability of a 12-year plantation cycle (4 rotations of 3 years each) under Mediterranean conditions with optimum irrigation (T1) and 50% irrigation reduction (T2), analysing other promising biomass uses in the form of bioproducts. A total of 138 trees of the highly productive hybrid ('AF2') in a SRC-trial were sampled monthly (first rotation). Additionally, data from an extensive poplar plantation network (30 sites) was used to complete data for the plantation cycle. The average C content for above- and below-ground biomass was 17.04 Mg C ha-1 yr-1 (T1), falling by 24% in T2. The net present value (NPV) in T1 (6461 € ha-1) was 52% lower under T2 conditions. Extra payments for C sequestration increased the NPV to 8023 for T1 and 4331 € ha-1 for T2. Roots represent an important C storage in the soil, accumulating 29.9 Mg C ha-1 (T1) and 22.8 Mg C ha-1 (T2) by the end of the cycle in our study. The mitigation potential is strongly fortified when the share of bioproducts in biomass end-use increases. Assuming a distribution of 50% bioenergy and 50% bioproducts, emission were reduced between -114 Mg CO2eq ha-1 (T1) and -88 Mg CO2eq ha-1 (T2) compared to BAU until end of the century. This scenario plays a crucial sink-effect role by storing C contained in biomass, which is not immediately released into the atmosphere.

Social-life cycle assessment of oil palm plantation smallholders in Bengkulu province, Indonesia

Smallholders are often seen as a weak point in the development of oil palm plantation production. The quality and yield of their production are considered low according to world market standards; the continuity of their production is irregular; and finally, improving the welfare of farmers is difficult to achieve. However, smallholder plantations have an important and strategic role in achieving sustainable development. This study aims to assess the social life cycle assessment of smallholder oil palm plantations in Bengkulu Province by involving stakeholders consisting of workers, local communities, farm owners, and value chain actors. A total of 600 respondents were selected using quota sampling and interviewed using a structured questionnaire. Data analysis was conducted using social-life cycle assessment, involving various social issues and relevant social indicators for each stakeholder. The findings in our research show that smallholder oil palm plantations still do not meet the minimum wage for workers, and the equipment used by workers is still very minimal in terms of security and safety guarantees. The price of palm oil continues to fluctuate, and plantation policies are constantly changing, making it difficult for oil palm owners to meet the standards and various rules that are set for managing oil palm plantations. In addition, oil palm plantations are no longer a guarantee for the fulfillment of food security conditions for household owners, workers, communities, and actors involved in the oil palm institutional chain. Our finding is that, surprisingly, there is a low level of commitment by smallholders and the government to sustainability in oil palm plantations. The Indonesian Sustainable Palm Oil and Roundtable on Sustainable Palm Oil as standards for sustainable oil palm plantations, as well as global standards for oil palm plantations to demonstrate environmentally friendly production processes, have not been able to compel smallholders to implement sustainable development in oil palm. Various policies formulated by the Indonesian government are perceived to have not addressed the core issues faced by small-scale farmers. Policies supporting small-scale farmers, particularly those related to increasing productivity, fostering and monitoring the environmental management of palm oil plantation activities, and ensuring ownership of plantation, are necessary for the achievement of sustainable smallholder palm oil plantation development.

Do Land Use Structure Changes Impact Regional Carbon Emissions? A Spatial Econometric Study in Sichuan Basin, China

Human activities are closely related to carbon emissions and the mechanism of land-use structure change on carbon emissions is unclear. In this study, 143 counties in the Sichuan Basin of China were used as sample units, and the land use structure of each sample unit in the Sichuan Basin was measured by applying the information entropy theory, analyzing the spatial and temporal evolutionary characteristics and the influencing relationships of land use structure and carbon emissions in the Sichuan Basin, by spatial econometric analysis of panel data on carbon emissions and information entropy of land use structure over five time periods from 2000 to 2018. The results indicate that: the carbon emission intensity and information entropy of land use in the Sichuan basin are increasing over the years, and the cross-sectional data reflect inconsistent spatial distribution characteristics, with greater changes around large cities; both carbon emissions and land use structure are spatially auto-correlated, the information entropy of land use positively affects carbon emission intensity; carbon emissions have positive spillover effects, and changes in land use structure have no obvious regional impact on surrounding areas; there may be potential threshold areas for the impact of land-use structure change on carbon emissions. This study has certain reference value for land use planning and carbon emission reduction policies.

Defect Removal and Rearrangement of Wood Board Based on Genetic Algorithm

Defects on a solid wood board have a great influence on the aesthetics and mechanical properties of the board. After removing the defects, the board is no longer the standard size; manual drawing lines and cutting procedure is time-consuming and laborious; and an optimal solution is not necessarily obtained. Intelligent cutting of the board can be realized using a genetic algorithm. However, the global optimal solution of the whole machining process cannot be obtained by separately considering the sawing and splicing of raw materials. The integrated consideration of wood board cutting and board splicing can improve the utilization rate of the solid wood board. The effective utilization rate of the board with isolated consideration of raw material sawing with standardized dimensions of wood pieces and board splicing is 79.1%, while the shortcut splicing optimization with non-standardized dimensions for the final board has a utilization rate of 88.6% (which improves the utilization rate by 9.5%). In large-scale planning, the use of shortcut splicing optimization also increased the utilization rate by 12.14%. This has certain guiding significance for actual production.