Around 2.3 billion people globally rely on biomass for cooking, contributing to severe health, environmental, and climate challenges, with household air pollution responsible for over 4 million deaths each year. This widespread dependence underscores the urgent need for accurate measurement of biomass consumption and associated emissions. The primary objective of this study is to enhance the understanding of household biomass energy use by quantifying the contributions of woody biomass and crop residues, examining seasonal consumption patterns, and estimating the resultant CO₂e emissions. The study’s novelty lies in its application of a digital, sensor-based system to continuously and accurately monitor biomass consumption across 420 households in Eastern Rwanda, conducted over three agricultural seasons. This approach generates high-resolution, region-specific data on the utilization of firewood, crop residues, and charcoal, while directly linking consumption patterns to CO₂e emissions. The findings indicate that firewood accounts for 86% of the total biomass used for cooking, followed by crop residues at 13% and charcoal at 0.8%. The estimated daily household consumption amounts to 3.1 kg of firewood, 0.47 kg of crop residues, and 0.03 kg of charcoal. The relatively high amount of crop residue suggests a chronic shortage of firewood, despite the intensive tree-planting campaigns. Firewood consumption remained stable during season A (short rainy) and season B (rainy), with a slight decrease in season C (dry). Crop residues decreased steadily from Season A to B, and further to C. The estimated annual CO2e emission from biomass combustion is 1.32 tons per household and 0.48 tons per capita. Digital methods provide precise, time-resolved data on fuel types and consumption, offering valuable insights for energy planning and carbon financing. Future research should integrate PM₂.₅ emissions to better assess health impacts and determine the sustainable balance between using crop residues as fuel and returning them to the soil.
Tag: biomass
A double-edged sword? Liana wood decomposes faster than tree wood
Lianas are increasing in many forests and show higher stem turnover rates and different chemical profiles compared with trees. However, liana deadwood decomposition dynamics have been overlooked. We redress this omission and hypothesize that liana wood decomposes faster than tree wood due to its larger vessels and higher nutrient content than trees, resulting in greater activity of both microbial and invertebrate decomposers. We tested this hypothesis in a common-garden decomposition experiment with deadwood of two size classes (2.5 and 4 cm diameter) belonging to 12 liana and 12 tree species in tropical China. Liana wood decomposed 28.6% faster than tree wood in the presence of invertebrates for large diameter but showed no significant difference for the smaller diameter. Initial contents of nitrogen, calcium, potassium and hemicellulose were higher for liana than tree wood. Likewise, liana bark had higher potassium and lignin contents than tree bark. The microbial contribution to decomposition based on mesh size exclusion of invertebrates, across lianas and trees, was similar. The presence of invertebrates more than doubled the decomposition rates for both lianas and trees. Overall, lianas decompose faster than trees, at least for larger diameter deadwood, and therefore may promote forest carbon and nutrient turnover rates.
Biomass fuel consumption and indoor air pollution from cooking appliances in refugee settings
Background
Indoor air pollution from reliance on firewood and charcoal remains a major health and environmental challenge in refugee and host communities. Although energy-efficient cooking technologies have the potential to reduce biomass fuel consumption and indoor air pollution, the comparative performance of different technologies under real-household conditions remains limited.
Objective
A study was conducted to quantify household cooking energy consumption and the resulting gas and particle concentrations from selected cooking technologies.
Methods
The study evaluated three cooking stoves: the Three-stone open fire, Lorena, and Traditional metallic stove (TMS), using firewood, charcoal, and briquettes. Eighteen cooking tests measured carbon monoxide (CO), carbon dioxide (CO2), fine particulate matter (PM₂.₅), fuel consumption, and cooking time.
Results
Firewood enabled the fastest cooking, while briquettes with the Lorena stove required twice the cooking time. The Lorena stove consumed slightly more firewood and substantially more briquettes than the TMS, but was more efficient with charcoal. CO levels when using firewood exceeded the World Health Organization (WHO) 1-hour guideline by 61% (Three-stone open fire) and 153% (Lorena), while briquettes remained within limits. Both ambient and cooking-related CO₂ concentrations remained below the Occupational Safety and Health Administration’s (OSHA) permissible exposure limit, whereas ambient PM₂.₅ concentrations averaged 28 µg/m³ , exceeding WHO air quality guidelines.
Conclusions
The study found context-dependent performance variations, challenging the assumption that improved cooking technologies are universally effective. Despite reducing cooking-related pollutants, briquettes and the Lorena stove alone cannot address elevated ambient PM₂.₅ levels, highlighting the need for integrated air quality interventions.
Agroforestry Practices for Woody Species Diversity and Woody Biomass Carbon Stock Enhancement in Northwestern Tigray, Ethiopia
Agroforestry plays an indispensable role in biodiversity conservation and ecosystem services. However, research on the ecological roles of different agroforestry practices in northwestern Tigray remains limited. This study to investigate the role of three agroforestry practices: homestead, parkland and woodlot in enhancing biodiversity and woody biomass carbon stock. A total of 68 sample plots representing 37 plots of parkland, 25 homestead, and 6 woodlots, were established from the purposively selected sites and households. 38 woody species from 22 families and 36 genera were recorded. Among these species, 26% were recorded in homestead, while 36.8% shared between homestead and parkland, and 18.4% across all land use types. Indigenous species accounted for 57.9%, with exotics represented 36.84% and invasive species 5.26%. The highest species diversity was found in homestead (H’ = 1.36), with significant variation among agroforestry types (p = 0.011). The total woody biomass were 32.36 ± 5.26, 17.74 ± 7.71 and 4.62 ± 0.76 Mg C ha-1 in homestead, woodlot and parkland agroforestry respectively. Cordia africana and Faidherbia albida and Ziziphus spina -christi were dominant in homestead and parkland agroforestry land use, whereas Eucalyptus camaldulensis and Acacia lahai dominated in the woodlots. Population structure analysis revealed low seedling regeneration in parklands due to agricultural disturbances. Woodlots in the study area are mostly established in productive farmlands thereby increasing competition with food production. Despite the competition of woodlots with agricultural crops for the productive lands, the findings generally indicate that homestead agroforestry is effective in enhancing ecological sustainability and mitigate climate change impacts. Thus, promoting agroforestry and proper woodlot establishment through engaging communities are essential for fostering community well-being and ensuring sustainable conservation of biodiversity.
Assessment of mangrove structures and biomass on islands along the Java Sea: a case study on Bawean Islands and Karimunjawa Islands
Mangroves on the islands along the Java Sea play a crucial role in supporting biodiversity, protecting coastlines, and sequestering carbon. However, there is a lack of information on mangrove structure and biomass in the area. This study aimed to assess the mangrove structures and biomass on Desa Daun, located on the Bawean Islands, and Kemujan Island, located on the Karimunjawa Islands, respectively. The study utilized a combination of line transect and quadrant plot methods with a size plot of 10×10 m. We established 7 line transects and 28 quadrant plots in the mangrove forest of Desa Daun and similarly set up 7 line transects and 21 quadrant plots on Kemujan Island. Within each quadrant, the mangrove species were identified, and their diameters at breast height (DBH) were recorded. To assess the relative significance of each species, the importance value index (IVI) was calculated, and allometric equations were applied to estimate biomass and carbon storage in the trees. PlanetScope imagery was also used to quantify the carbon stock of mangroves on those islands. In Desa Daun, 13 mangrove species were identified, while 12 species were recorded on Kemujan Island. The species Nypa fruticans and Excoecaria agallocha exhibited the highest IVI in Desa Daun and Kemujan Island, respectively. Notably, Rhizophora apiculata demonstrated the greatest biomass in both locations, with measurements of 43.08 Mg B/ha in Desa Daun and 102.22 Mg B/ha in Kemujan Island. Overall, mangrove stands on Desa Daun stored biomass of 113.60 Mg B/ha and carbon of 50.98 Mg C/ha, whereas mangrove stands on Kemujan Island stored biomass of 295.04 Mg B/ha and carbon of 131.95 Mg C/ha. Mangrove stands of the whole Bawean Islands sequestered 22,941 Mg C, while Karimunjawa Islands hold much higher C stocks, 79,451 Mg C. Despite being smaller in size, the Karimunjawa Islands have more extensive mangrove coverage compared to the Bawean Islands due to their geomorphological characteristics, which in turn influence their mangrove structures and carbon stocks. However, the loss of mangroves in the Karimunjawa Islands due to aquaculture expansions could increase carbon loss in the islands.
Tree biomass equations from terrestrial LiDAR: A case study in Guyana
Large uncertainties in tree and forest carbon estimates weaken national efforts to accurately estimate aboveground biomass (AGB) for their national monitoring, measurement, reporting and verification system. Allometric equations to estimate biomass have improved, but remain limited. They rely on destructive sampling; large trees are under-represented in the data used to create them; and they cannot always be applied to different regions. These factors lead to uncertainties and systematic errors in biomass estimations. We developed allometric models to estimate tree AGB in Guyana. These models were based on tree attributes (diameter, height, crown diameter) obtained from terrestrial laser scanning (TLS) point clouds from 72 tropical trees and wood density. We validated our methods and models with data from 26 additional destructively harvested trees. We found that our best TLS-derived allometric models included crown diameter, provided more accurate AGB estimates (R2 = 0.92-0.93) than traditional pantropical models ( R2 = 0.85-0.89), and were especially accurate for large trees (diameter > 70 cm). The assessed pantropical models underestimated AGB by 4 to 13%. Nevertheless, one pantropical model (Chave et al. 2005 without height) consistently performed best among the pantropical models tested (R2 = 0.89) and predicted AGB accurately across all size classes-which but for this could not be known without destructive or TLS-derived validation data. Our methods also demonstrate that tree height is difficult to measure in situ, and the inclusion of height in allometric models consistently worsened AGB estimates. We determined that TLS-derived AGB estimates were unbiased. Our approach advances methods to be able to develop, test, and choose allometric models without the need to harvest trees.
Stem-nodulating legumes as relay-cropped or intercropped green manures for lowland rice
Green manures have consistently shown positive contributions to tropical rice (Oryza sativa) production, but will be produced on a substantial scale only when they fit into appropriate niches in the cropping system. We examined the effects of intercropped and relay-cropped Sesbania rostrata and Aeschynomene afraspera as green manures (GM) on the companion and succeeding rice crops for three consecutive seasons in an environment where two rice crops are grown each year. Pregerminated seeds of the legumes were sown between rice rows immediately after transplanting or at the ripening stage of the rice crops. They also were broadcast at the ripening stage of hill-planted rice. The effects of the GM on rice, with or without added urea, were compared with the effects of varying urea-N rates in the absence of the GM.Surface water was detrimental to pregerminated GM seeds. A. afraspera was more damaged by flooding because it emerged 4 d later than S. rostrata. Green manure effects on either the companion or succeeding rice crops varied as a function of GM crop stand and biomass production. Green manure biomass yield was greater with broadcasting than with row seeding.Green manure relayed into dry-season rice grew vigorously and increased the grain yield of the succeeding rice crop equivalent to the application of 30 kg urea-N/ha. The growth of GM relayed into wet-season rice was suppressed by the short photoperiod in that season. A urea-N topdress application did not improve the effect of GM on rice yield. The effect of relayed GM on the succeeding wet-season rice crop also was equivalent to or exceeded the effect of 60 kg urea-N/ha. The results indicated the potential feasibility of relaying GM in a rice cropping system when the turnaround time is too short to raise a preceding monocrop GM.
Growth and biomass production of Inga edulis in the Peruvian Amazon
Growth and biomass production of some Leucaena leucocephala accessions grown at Makoka, Malawi
Growth, coppicing, and biomass production was compared of 17 accessions of Leucaena leucocephala widely distributed for planting in East and Southern Africa by National Tree Seed Centres in Malawi, Tanzania, Zambia and Kenya. A widely used accession in alley cropping in West Africa was also included. Seed origins were sites in Malawi, Zambia, Nigeria, Kenya and Tanzania. The trial was established in 1989 on a sandy loam soil in a subhumid unimodal rainfall area at Makoka, Malawi. Assessments were done for survival at 3 months, and at 15 and 30 months after establishment for height, diameter at the root collar, number of branches and biomass production. Survival was generally good for most accessions (>90%) with the exception of an accession from Machakos, Kenya (No. 84511) which had a survival of only 67%. Fifteen months after establishment, accessions from Yimbo (Kenya), and 2 K8 accessions from Kasama (Zambia) and Machakos (Kenya) achieved the best height (>3.2 m). Poor accessions included No. 84511 from Machakos (Kenya), Peru (ex. Makoka, Malawi), and the West African accession from IITA (Nigeria) whose height was <2.5 m. At 15 months, 12 of the accessions tested showed high total biomass production (dry weight, 25-38 t/ha). The foliage biomass (leaves, twigs and pods) yields exceeded 10 t/ha in all but one accession from Makoka, Malawi and another from Korogwe, Tanzania. After clear cutting, all the Leucaena accessions coppiced and grew exceptionally well, achieving very high biomass production in only 15 months. The highest yields were produced by accessions from Isiolo, Kenya (47.7 t/ha), Namiyanga, Malawi (42.2 t/ha), Yimbo, Kenya (36.3 t/ha) and accession Pursa from Kasama, Zambia (35.6 t ha-1). Poor accessions yielded less than 20 t/ha and included local seed sources of Peru and Cunningham from Makoka, Malawi and the West African accession from IITA, Ibadan, Nigeria.
Does Biochar Application Improve Paddy Productivity and Net Returns? An On-Farm Evidence and Farmers’ Perceptions in India
Transforming agricultural waste into biochar can potentially generate renewable energy, capture carbon, improve soil health, and mitigate climate change. However, its adoption is still minimal due to ambiguity in the realisation of associated benefits, as the evidence of its impact on crop yield based on on-farm data is very limited. In this study, we analysed a comprehensive dataset of 962 households across three states of India, viz. Madhya Pradesh, Maharashtra, and Odisha. Findings show that the application of biochar had a positive and significant effect on crop yield enhancement (4.34%) and net return (29.34%), and a reduction in cost of cultivation (1.52%). However, the effect size is much smaller than that reported in experimental studies conducted in controlled conditions. Farmers who are more experienced in farming, have irrigation facilities, and diversify crops and enterprises perceive benefits from biochar. Improvement in soil fertility is the primary benefit farmers perceive from biochar, whereas the limited availability of biochar and lack of incentives are the major constraints in adoption. The study suggests strategies and policies for outscaling and creating enabling environments for biochar production in Indian agriculture.