Forests play a vital role in the global carbon balance and combating global climate change by sequestering and retaining carbon from the atmosphere in their biomass and soil. Thus, this study aims to estimate the carbon stocks in the biomass and soil along with various environmental factors in the Geramo forest in southern Ethiopia. Ninety-six plots (20 × 20 m2) were laid at a distance of 250 m along 16 line transects that were laid 300 m apart. Five 1 × 1 m2 subplots (4 at the corner and 1 at the center) were laid inside each main plot for LHG and soil data collection. The results revealed that the estimated total carbon stocks and mean carbon stock densities of the study forest were 57994 Mg h−1and 604 ± 344 Mg h−1, respectively, with a mean CO2 equivalent of 2217 ± 1262 Mg h−1. This result indicates the remarkable role of the Geramo forest in carbon stock and sequestration potential compared with other remnant forests in Ethiopia. Thus, the Geramo forest plays a crucial role in climate change mitigation through carbon sequestration, and hence, this forest can generate carbon credits as financial benefits to the nearby population in the future. The results also revealed that anthropogenic disturbances were negatively associated with the carbon stocks of the forest. Therefore, sustainable forest conservation activities are needed to conserve forest resources, protect the forest from growing anthropogenic disturbances, and sustain its current global climate change mitigation and adaptation benefits.
Tag: carbon sinks
Intensive field sampling increases the known extent of carbon-rich Amazonian peatland pole forests
Peatland pole forest is the most carbon-dense ecosystem in Amazonia, but its spatial distribution and species composition are poorly known. To address this knowledge gap, we quantified variation in the floristic composition, peat thickness, and the amount of carbon stored above and below ground of 102 forest plots and 53 transects in northern Peruvian Amazonia. This large dataset includes 571 ground reference points of peat thickness measurements across six ecosystem types. These field data were also used to generate a new land-cover classification based on multiple satellite products using a random forest classification. Peatland pole forests are floristically distinctive and dominated by thin-stemmed woody species such as Pachira nitida (Malvaceae), Platycarpum loretense (Rubiaceae), and Hevea guianensis (Euphorbiaceae). In contrast, palm swamps and open peatlands are dominated by Mauritia flexuosa (Arecaceae). Peatland pole forests have high peat thickness (274 ± 22 cm, mean ± 95% CI, n = 184) similar to open peatlands (282 ± 46 cm, n = 46), but greater than palm swamps (161 ± 17 cm, n = 220) and seasonally-flooded forest, terra firme, and white-sand forest where peat is rare or absent. As a result, peatland pole forest has exceptional carbon density (1,133 ± 93 Mg C ha−1). The new sites expand the known distribution of peatland pole forest by 61% within the Pastaza-Marañón Foreland basin, mainly alongside the Tigre river, to cover a total of 7540 km2 in northern Peruvian Amazonia. However, only 15% of the pole forest area is within a protected area, whilst an additional 26% lies within indigenous territories. The current low levels of protection and forest degradation but high threat from road paving projects makes the Tigre river basin a priority for conservation. The long-term conservation of peatland pole forests has the potential to make a large contribution towards international commitments to mitigate climate change.
Effects of diverse mangrove management practices on forest structure, carbon dynamics and sedimentation in North Sumatra, Indonesia
For decades, mangrove forests have been under tremendous pressure due to deforestation and conversion. To sustainably manage the mangroves that remain, an ecosystem approach to management is essential. Two different management regimes – conservation and restoration – were assessed, looking at their respective effects on forest structure and carbon cycling capacity, when compared with degraded mangrove. We found that mangrove restoration enhanced tree density, while mangrove conservation was able to maintain species diversity. In terms of carbon budgets, aboveground carbon was lower in restored mangrove (79.40 ± 37.41 Mg C ha−1) when compared with conserved mangrove (92.26 ± 22.65 Mg C ha−1), but was almost double that found in degraded mangrove (39.89 ± 27.49 Mg C ha−1). Although conserved mangrove had higher aboveground carbon, lower amounts of soil carbon were found in conserved mangrove (127.49 ± 33.21 Mg C ha−1) than in restored and degraded mangrove (236.26 ± 20.33 Mg C ha−1 and 139.17 ± 25.44 Mg C ha−1, respectively). The elevation change was highest in degraded mangrove (41.7 ± 24.0 mm yr−1), followed by restored (20.7 ± 14.6 mm yr−1) and conserved mangrove (12.2 ± 3.9 mm yr−1). Carbon burial in conserved mangrove (1.20 ± 1.90 Mg C ha−2 yr−1) was double that of degraded mangrove (0.63 ± 0.60 Mg C ha−2 yr−1). Ultimately, we conclude that although a conserved mangrove is not always the end result of mangrove restoration and sustainable management, finding balance between structural development and ecosystem function is essential to serve different objectives, including biodiversity maintenance.
Mangrove selective logging sustains biomass carbon recovery, soil carbon, and sediment
West Papua’s Bintuni Bay is Indonesia’s largest contiguous mangrove block, only second to the world’s largest mangrove in the Sundarbans, Bangladesh. As almost 40% of these mangroves are designated production forest, we assessed the effects of commercial logging on forest structure, biomass recovery, and soil carbon stocks and burial in five-year intervals, up to 25 years post-harvest. Through remote sensing and field surveys, we found that canopy structure and species diversity were gradually enhanced following biomass recovery. Carbon pools preserved in soil were supported by similar rates of carbon burial before and after logging. Our results show that mangrove forest management maintained between 70 and 75% of the total ecosystem carbon stocks, and 15–20% returned to the ecosystem after 15–25 years. This analysis suggests that mangroves managed through selective logging provide an opportunity for coastal nature-based climate solutions, while provisioning other ecosystem services, including wood and wood products.
Taking the pulse of Earth’s tropical forests using networks of highly distributed plots
Tropical forests are the most diverse and productive ecosystems on Earth. While better understanding of these forests is critical for our collective future, until quite recently efforts to measure and monitor them have been largely disconnected. Networking is essential to discover the answers to questions that transcend borders and the horizons of funding agencies. Here we show how a global community is responding to the challenges of tropical ecosystem research with diverse teams measuring forests tree-by-tree in thousands of long-term plots. We review the major scientific discoveries of this work and show how this process is changing tropical forest science. Our core approach involves linking long-term grassroots initiatives with standardized protocols and data management to generate robust scaled-up results. By connecting tropical researchers and elevating their status, our Social Research Network model recognises the key role of the data originator in scientific discovery. Conceived in 1999 with RAINFOR (South America), our permanent plot networks have been adapted to Africa (AfriTRON) and Southeast Asia (T-FORCES) and widely emulated worldwide. Now these multiple initiatives are integrated via ForestPlots.net cyber-infrastructure, linking colleagues from 54 countries across 24 plot networks. Collectively these are transforming understanding of tropical forests and their biospheric role. Together we have discovered how, where and why forest carbon and biodiversity are responding to climate change, and how they feedback on it. This long-term pan-tropical collaboration has revealed a large long-term carbon sink and its trends, as well as making clear which drivers are most important, which forest processes are affected, where they are changing, what the lags are, and the likely future responses of tropical forests as the climate continues to change. By leveraging a remarkably old technology, plot networks are sparking a very modern revolution in tropical forest science. In the future, humanity can benefit greatly by nurturing the grassroots communities now collectively capable of generating unique, long-term understanding of Earth’s most precious forests.
Impact of land use and land cover changes on carbon storage in rubber dominated tropical Xishuangbanna, South West China
Land use and land cover (LULC) play a significant role in carbon regulation. South-China accounts for ~65% of China’s carbon sink. In Xishuangbanna (South-China), rubber is expanding rapidly creating an urgent need to understand and monitor LULC change and how spatial variation affects carbon storage (CS). This is vital for the formation and implementation of better land use management practices. We studied LULC changes of 22-year period; addressing how these changes have affected the CS. We quantified LULC changes between1988 and 2010 using remote sensing methods and calculated CS changes using InvEST. Results showed that between 1988 and 2010, the rate of deforestation accelerated to 203.2 km2 y−1 and ~23% of forest were lost. Conversion of natural forest to rubber was responsible for 78% of this deforestation. Rubber expansion rate was 153.4 km2 y−1. Changes to LULC drove a temporal CS reduction 0.223 Tg C/km2. Local stakeholders have strong economic interest in converting land to more profitable plantations. Government efforts is required to control land conversion through new policies and incentives to retain natural forest. Assessment of specific potential land use change will be required to avoid promoting the conversion of high carbon storage land uses to low carbon storage land uses.
Soils, sinks, and smallholder farmers: Examining the benefits of biochar energy transitions in Kenya
Besides reducing fuel demands and indoor air pollution, pyrolytic cooking stoves produce a by-product (biochar) that can improve soil fertility and serve as a sink for carbon sequestration. Most smallholder farmers in Africa depend on wood for fuel, suffer from exposure to smoke and soils in their cultivated farms are deteriorating. Biochar (bio-charcoal) production has potentials to reduce energy requirement, diminish exposure to smoke, improve soil health and ease household activities traditionally associated with female labour. However, introducing new technologies and behaviours that tackle existing problems without creating new ones is a complex endeavour. Transitions need to be anticipatory, comprehensive and inclusive. Having this in mind, a trans-disciplinary study was conducted from 2013 to 2019 with 150 households in three agro-ecological zones of Kenya. The socio-economic conditions, the uses of fuels and stoves, the crops grown and fertilizers used, as well as the labour division within households were documented. Selected households were given pyrolitic cooking stoves and trained in applying biochar to the soil. After two years of using the cooking stoves and applying biochar, studies were conducted to assess the feasibility and preliminary impacts based on the households own perceptions and experiences. The results showed that the strategy represented a viable option to deal with fuel use efficiency, exposure to indoor smoke and soil degradation, as well as easing the burden on female labour.
Effects of degraded grassland conversion to mango plantation on soil CO2 fluxes
Land use changes are of serious concern due to its effects on soil carbon stock, which is second largest anthropogenic source of atmosphere CO2. To better understand these effects in typical and fragile ecosystems like dry-hot valley regions, we quantified changes in soil properties (pH, organic carbon, total nitrogen, phosphorus, microbial biomass carbon contents, activities of β-glucosidase, beta-N-acetyl-glucosaminidase, acid phosphatase) and CO2 efflux before (degraded grassland) and after (mango plantation) land use change in a dry-hot valley region. Most soil chemical properties remained unaffected after conversion due to generally low regional nutrient levels. Principal component analysis revealed the decline of soil heterogeneity of the selected properties (pH, SOC, TN, TP, AP), which will be useful for future unified management. Compared to grassland, CO2 efflux in mango plantation increased by 20–69% after land use change, more factors and their interactions were responsible for CO2 efflux from soil in mango plantations. The temperature sensitivity (Q10: 0.68–1.98) of CO2 efflux in both land use types was low due to the low soil moisture at high temperatures. Soil water content was the primary factor affecting CO2 efflux in the dry-hot valley region, followed by microbial biomass carbon. In summary, the CO2 efflux increased shortly after the land use change (within first year), even though absence of significant quantitative change of soil properties, and low temperature sensitive (Q10) before and after conversion and its difference between land use types is opposite in dry and wet season.
Ten golden rules for reforestation to optimize carbon sequestration, biodiversity recovery and livelihood benefits
Urgent solutions to global climate change are needed. Ambitious tree-planting initiatives, many already underway, aim to sequester enormous quantities of carbon to partly compensate for anthropogenic CO2 emissions, which are a major cause of rising global temperatures. However, tree planting that is poorly planned and executed could actually increase CO2 emissions and have long-term, deleterious impacts on biodiversity, landscapes and livelihoods. Here, we highlight the main environmental risks of large-scale tree planting and propose 10 golden rules, based on some of the most recent ecological research, to implement forest ecosystem restoration that maximizes rates of both carbon sequestration and biodiversity recovery while improving livelihoods. These are as follows: (1) Protect existing forest first; (2) Work together (involving all stakeholders); (3) Aim to maximize biodiversity recovery to meet multiple goals; (4) Select appropriate areas for restoration; (5) Use natural regeneration wherever possible; (6) Select species to maximize biodiversity; (7) Use resilient plant material (with appropriate genetic variability and provenance); (8) Plan ahead for infrastructure, capacity and seed supply; (9) Learn by doing (using an adaptive management approach); and (10) Make it pay (ensuring the economic sustainability of the project). We focus on the design of long-term strategies to tackle the climate and biodiversity crises and support livelihood needs. We emphasize the role of local communities as sources of indigenous knowledge, and the benefits they could derive from successful reforestation that restores ecosystem functioning and delivers a diverse range of forest products and services. While there is no simple and universal recipe for forest restoration, it is crucial to build upon the currently growing public and private interest in this topic, to ensure interventions provide effective, long-term carbon sinks and maximize benefits for biodiversity and people.
Variation in vegetation and ecosystem carbon stock due to the conversion of disturbed forest to oil palm plantation in Peruvian Amazonia
Peruvian national and regional plans promoting oil palm have prompted a rapid expansion of the crop in the Amazonian region. This expansion has taken place primarily at the expense of forest, both undisturbed and disturbed. Assessments of carbon emissions from forest-to-oil palm conversion have essentially been confined to Southeast Asia, and research on Peruvian Amazonian forests has mainly targeted undisturbed sites. This study characterizes the vegetation structure and composition of disturbed forests and smallholder oil palm plantations and evaluates the change in ecosystem (that is, phytomass and soil) carbon stocks associated with forest-to-oil palm conversion. Inventories were conducted in four degraded forest sites neighboring six oil palm plantation sites in Ucayali. Time-averaged carbon stocks over the 30-year oil palm rotation were computed from models developed upon the sampled chronosequence (1 to 28 years old). Disturbed forests harbored species typical of primary forests, pioneer species and gaps opportunistic species. Their tree basal area (18.7 ± 1.4 m2 ha-1) and above-ground C stock (71.3 ± 4.2 Mg C ha-1) were, respectively, 50 and 60% of the values of undisturbed forests from the literature. The growth curve for oil palm above-ground biomass was consistently below models developed for plantations in Indonesia. Thirty-year time-averaged ecosystem C stock (Mg C ha-1) in oil palm plantations (78.2 ± 2.0) represented 55% of the stock in disturbed forest (140.9 ± 5.8), resulting in a 62.7 ± 6.1 loss from such conversion. These results reinforce recommendations to redirect oil palm expansion toward low-carbon degraded lands, sparing disturbed and undisturbed forests.