Total Ecosystem Carbon Stocks Research Articles

Structural diversity and carbon stocks in a tropical semi-evergreen forest in Bangladesh

Tropical forests are well-known as highly productive terrestrial ecosystems, which contribute significantly to the global carbon (C) cycle. Studies indicate a correlation between the structural diversity of forests and carbon stocks in the overall forest carbon stocks, and this relationship varies across tropical ecosystems. Understanding this connection is crucial to preventing the transfer of threats to unprotected areas when safeguarding specific forests. The present study was conducted in the undisturbed natural forests of Rema Kalenga Wildlife Sanctuary, Habigonj, Bangladesh. The study aimed to estimate C stocks within the soil-vegetation system of this forest ecosystem and elucidate relationships with stand structural diversity, focusing on vertical stratification and spatial association of tree species. Stand-level C stock models, constructed through tree-level carbon stocks using allometric equations, were based on stand variables such as basal area and mean or dominant tree height. Results identified five canopy strata, with strata two and three accounting for 60% of C stocks. The importance value index of tree species demonstrated a significant association with the C stocks contribution of tree species. The total ecosystem carbon stock ranged from 185 to 220 Mg ha−1, with aboveground 103 to 132 Mg ha−1, belowground 21 to 26 Mg ha−1, litter 2.4 to 4.4 Mg ha−1, dead wood 0.5 to 4.9 Mg ha−1 and soil 11 to 44 Mg ha−1. Species diversity indices exhibited weaker relationships with C stocks, while Pielou's evenness index demonstrated a strong negative relationship (P < 0.05) to C stocks. This comprehensive assessment provides insights into the C dynamics of the forest ecosystem. It offers valuable information for policymakers devising climate change mitigation strategies through the conservation management of tropical forests as crucial C sinks.

The inclusion of Amazon mangroves in Brazil’s REDD+ program

The Legal Amazon of Brazil holds vast mangrove forests, but a lack of awareness of their value has prevented their inclusion into results-based payments established by the United Nations Framework Convention on Climate Change. Based on an inventory from over 190 forest plots in Amazon mangroves, we estimate total ecosystem carbon stocks of 468 ± 67 Megagrams (Mg) ha−1; which are significantly higher than Brazilian upland biomes currently included into national carbon offset financing. Conversion of mangroves results in potential emissions of 1228 Mg CO2e ha−1, which are 3-fold higher than land use emissions from conversion of the Amazon rainforest. Our work provides the foundation for the inclusion of mangroves in Brazil’s intended Nationally Determined Contribution, and here we show that halting mangrove deforestation in the Legal Amazon would generate avoided emissions of 0.9 ± 0.3 Teragrams (Tg) CO2e yr−1; which is equivalent to the annual carbon accumulation in 82,400 ha of secondary forests.

Carbon stocks and effluxes in mangroves converted into aquaculture: a case study from Banten province, Indonesia

Aquaculture is one of the main drivers of mangrove loss across Southeast Asian countries. The conversion of mangroves to aquaculture generates substantial loss of carbon stocks and reduces carbon storage capacity. Here, we present total ecosystem carbon stocks (TECS), carbon dioxide (CO2) and methane (CH4) effluxes obtained from mangrove forests (fringe and interior mangroves), silvofishery aquaculture ponds (dense and sparse mangroves), and non-silvofishery aquaculture ponds in Sawah Luhur, Banten, Indonesia. We found no significant difference in TECS across five land uses, ranging from 261 ± 14 Mg C ha-1 in non-silvofishery ponds to 574 ± 119 Mg C ha-1 in fringe mangroves. Most of these stocks were found in the soil carbon pool (87%) in fringe and interior mangroves. However, the conversion of mangroves to aquaculture ponds resulted in soil carbon loss from -6% to 60%. The highest soil CO2 effluxes during dry and wet seasons were observed in interior mangroves (151 ± 12 mg CO2 m-2 h-1). The highest soil CH4 effluxes were found in fringe mangroves with 0.13 ± 0.04 mg CH4 m-2 h-1. The highest aquatic CO2 and CH4 effluxes were found in dense silvofishery ponds, at 118 ± 7 mg CO2 m-2 h-1 and 0.38 ± 0.04 mg CH4 m-2 h-1, respectively. Our findings suggest that land use that includes mangroves (i.e., mangrove forest and/or silvofishery ponds) tends to have higher carbon stocks, soil, and aquatic CO2 and CH4 effluxes, compared to aquaculture ponds without mangroves. It is therefore crucial to maintain mangroves for natural carbon capture and storage through carbon stock enhancement.

Soils and Carbon Pools on the Shungite Rocks of South Karelia under Different Types of Land Use

The azonal organo-accumulative soils (Umbrisols) on shungite rocks and the effect of land use on their properties and ecosystem carbon stock have been studied. The changes in soil profile morphology, main agrochemical and microbiological characteristics of the upper horizons, Corg and Cmic stocks in the 100-cm soil layer, and the structure of carbon pools are analyzed. Pine forest (control), arable land, hayfield, young alder stand, and middle-aged mixed forest are examined. In contrast to zonal soils, a change in land use does not considerably transform the properties of shungite soils. The removal of stones has the greatest effect, leading to the formation of developed arable horizons. The soils are characterized by highly skeletal shallow weakly differentiated profile, low bulk density, and pH close to neutral. A wide range of the Corg content (1.6 to 11.7%) results from a heterogeneous composition of the parent rock. Agricultural development contributes to the accumulation of exchangeable bases and available potassium and phosphorus, the contents of which are initially elevated in shungite soils. Characteristic of all examined sites is a high rate of organic matter mineralization (C/N ratio ≤17). A low Cmic content (84–245 mg C/kg) is recorded in the soils, which is explainable with a low availability of the substrate determined by a lithogenic nature of carbon and increased concentrations of heavy metals and lanthanides in shungite rocks. Soil Corg stock varies in the range of 17–251 t C/ha and Cmic stock, of 6–43 g C/m2. The total ecosystem carbon stock is the highest in hayfield (259 t C/ha) and lowest in young forest (74 t C/ha). The total carbon stock in the arable sites, middle-aged forest stand, and control forest is within 169–211 t C/ha.

Blue carbon stock heterogeneity in Brazilian mangrove forests: A systematic review

This is the first systematic review and meta-analysis of blue carbon stocks in Brazilian mangroves. We evaluated the effect of characteristics and site status (impacted versus non-impacted) on carbon stocks found in the various compartments on total ecosystem carbon stock (TECS). TECS followed an inverse trend with the latitudinal position: the highest values were found on the North coast (mean 511 Mg C ha−1), followed by the Northeast and Southeast. A similar latitudinal trend was observed for sediment and above-ground biomass carbon stocks. Site status also significantly affected TECS and sediment carbon stocks. The heterogeneity observed in carbon stocks suggests that tidal regime, latitudinal position, climate, and human impacts jointly drive the processes related to sequestration and storage. Brazilian mangroves store ~0.44 PgC, representing 10–12 % of the world TECS. This highlights Brazilian mangroves as a global blue carbon hotspot, and as an efficient nature-based solution for carbon dioxide removal.

Carbon sequestration and storage capacity of Chinese fir at different stand ages

In southern China, Chinese fir Cunninghamia lanceolata is one of the most important native conifer trees, widely used in afforestation programs. This area has the largest forestland atmospheric carbon sink, and a relatively young stand age characterizes these forests. However, how C. lanceolata forests evolved regarding their ability to sequester carbon remains unclear. Here we present data on carbon storage and sequestration capacity of C. lanceolata at six stand ages (5−, 10−, 15−, 20−, 30− and 60 − year−old stands). Results show that the carbon stock in trees, understory, vegetation, litter, soil, and ecosystem significantly increased with forest age. The total ecosystem carbon stock increased from 129.11 to 348.43 Mg ha−1 in the 5− and 60 − year−old stands. The carbon sequestration rate of C. lanceolata shows an overall increase in the first two stand intervals (5–10 and 10–15), peaks in the 15–20 stand intervals, and then decreases in the 20–30 and 30–60 stand intervals. Our result revealed that carbon sequestration rate is a matter of tree age, with the highest sequestration rates occurring in the middle age forest (15–20 − year−old). Therefore, this information may be useful for national climate change mitigation actions and afforestation programs, since forests are primarily planted for this purpose.

Woody species diversity and carbon stock potentials in homegarden agroforestry and other land use systems, northern Ethiopia

Homegarden agroforestry (HGAF) provides wider ecosystem services in the agricultural landscapes in the tropics. However, the potentials of the homegardens for floristic species conservation and climate change mitigation were less empahsized. The present study was designed to investigate woody species diversity, carbon stock, and the relationships between woody plant species and carbon stock in the HGAF and other land use types. Three land use types were purposively selected, totalling 60 nested sample plots. The stand structure and woody plant species diversity were determined. Biomass carbon stocks were estimated employing appropriate allometric equations. Soil Organic Carbon (SOC) stocks (at 0–30 and 30–60 cm layers) were calculated. The result of the study showed a total of 38 woody plant species recorded from both HGAF and exclosures, but no report from cropland. The abundance, basal area, stem density, species richness, and Shannon and Simpson diversity indices were significantly higher in the HGAF than in exclosures. The mean SOC stock was the highest in HGs (122.13 ± 19.12 Mg ha-1). The estimated mean total ecosystem carbon stock of HGAF, cropland, and exclosure was 171.17 ± 37.25, 78.06 ± 11.97, and 92.5 ± 17.33 Mg ha-1, respectively, which was statistically significant among land use types. A positively significant correlation was observed between diversity, richness, and abundance of woody species and carbon stocks both in the HGAF and exclosure land use systems. The current study confirmed that increased woody species diversity in HGAF enhanced carbon sequestration. The HGAF land use in the northern parts of the country is scanty as compared to the southern part, where there is a rich woody species diversity. Therefore, it is recommendable to promote HGAF across agricultural landscapes of the study area, which enhances biodiversity conservation and mitigation of climate change impacts.

Does age matter? Unravelling the effects of replanted mangrove forests on the total ecosystem carbon stocks

Mangrove replanting is a fundamental approach for restoring the ecosystem services in the mangrove ecosystems. This study assesses and compares the total ecosystem carbon stock (TECS) in different stand ages of replanted mangrove forests (1, 2, 5, 9, 10 and 21 years old and an Intact/Undisturbed Forest as the control) in the west coast of Peninsular Malaysia. The preferred species for planting are Rhizophora mucronata, R. apiculata and Bruguiera parviflora, while the Intact Forest only has one species, Avicennia marina. Most sites recorded additional species recruits after a few years. The study determines the total ecosystem carbon stock (TEC) based on the above-ground standing trees, below-ground, dead wood and soil, uses the established allometric equations to calculate the biomass and carbon stock in vegetation, and determines the soil carbon using the LI method. In general, the results showed a linear relationship between the TECS and stand age (R=0.86, y=70.993x + 353.51). The ten-year-old stand had the highest TECS (875.79 Mg C ha −1), the one-year-old had the lowest (376.91 Mg C ha −1), and the Intact Forest was moderate at 530.57 Mg C ha −1. In all cases, soil contributed the highest percentage of 75%–98% to the TECS. The Principal Component Analysis (PCA) revealed that the primary determiners of the TECS are the stand age, followed by mangrove tree structure and soil carbon accumulation capacity.

Carbon stock in different ecological types of mangroves in a karstic region (Yucatan, México): an opportunity to avoid site scale emissions

Mangroves are coastal ecosystems recognized by their capacity to store organic carbon, even more so than tropical and temperate forests. Therefore, they contribute to the local adaptation and mitigation of climate change. Mangroves have different characteristics that origin mangrove ecological types. There are few studies on mangroves in karstic environments, where there is spatial heterogeneity associated with topography-hydroperiod-nutrient interactions. To estimate the total carbon stock in mangroves and determine whether carbon storage differs according to the mangrove ecological type in a natural protected area in the karstic region of the Yucatan Peninsula (northern Ria Celestun Biosphere Reserve), a study was conducted following the recommendations of the IPCC Good Practice Supplement for wetlands and standardized methods used in mangroves studies around the world. According to the results, mangroves associated with springs, called “petenes” or hammock mangroves, showed higher total ecosystem carbon stock (683.7 Mg C ha–1) than fringe, basin, and dwarf mangrove ecological types (429, 385, and 214 Mg C ha–1, respectively). Above- and below-ground carbon stock was different between mangrove ecological types. Carbon stock variation was related to environmental hydrology variables (flooding level, interstitial water salinity, and redox potential). According to the δ13C analysis from the surface soil, carbon accumulated in mangrove sediments in a karstic scenario is mainly autochthonous and predominantly originates from mangrove leaves. Carbon stock in mangroves in the northern Ria Celestun Biosphere Reserve was 9.7 Tg C, of which 40.7% comes from dwarf mangroves due to their extension. These results could be used as a tool for developing specific management actions at regional or local scales for mangrove restoration and conservation.

The potential of bamboo forests as a carbon sink and allometric equations for estimating their aboveground biomass

AbstractBamboo forests in Colombia and the Andean region of South America represent high-value ecosystems that provide ecological and economic benefits with local and global impacts. One of the ecosystem services provided by these forests is associated with their capacity to store carbon. In this study, data collected from monitoring plots were used to estimate the carbon content in different pools. Bamboo biomass (Bba), tree biomass (Btree), litter (Cli) and soil organic carbon (SOC) were assessed. The approximate total ecosystem carbon stock (TECaprox) ranged from 198.4 Mg C ha−1 to 330.9 Mg C ha−1 and bamboo carbon Cba represents approximately 50%. In addition, considering the relevance of developing tools to facilitate bamboo inventory and biomass estimates, allometric equations (AE) to estimate bamboo aboveground biomass (AGB) were fitted using the diameter of culms at breast height (dbh) and the total culm length (l) as predictor variables. The fitted AEs included the weighted linear, weighted log-transformed and weighted nonlinear fixed effect models. To compliance the additivity of biomass components a simultaneous systems of biomass equations (seemingly unrelated regressions) were also fitted. The precision and accuracy were assessed considering the residual diagnostic plots and statistics, such as the root-mean-square error (RMSE), RMSE percentage error (RMSEPE) and the Furnival’s index (Fln) for weighted log-transformed models and cross-validation. The performance of the models was similar with an RMSE of approximately 10 kg and 26% of RMSEPE, with slightly lower error for the weighted log-transformed model for the fitting and validation phases. A proper performance was also evidenced for the simultaneous approach for predicting AGB. Bamboo forests showed high relevance as carbon sinks and therefore might be considered strategic tropical ecosystems for climate change mitigation. On the other hand, the fitted AE exhibited proper performance and therefore provided reliable possibilities for estimating the AGB of bamboo during inventories. For practical reasons, the use of models with dbh as a predictor variable is recommended.

Carbon stocks and sequestration rate in mangroves and its major influencing factors from highly urbanised port city, southern India

This study estimated the total ecosystem carbon stock (TECS) and sediment carbon sequestration rate through burial for fragmented mangrove habitats of Kochi, south-west coast of India. The mean TECS of Kochi mangroves was estimated at 335.33 ± 184.47 t C ha−1, with above ground biomass of 171.68 ± 104.42 t C ha−1, belowground biomass of 83.30 ± 41.98 t C ha−1, litterfall carbon as dead biomass of 7.12 ± 2.81 t C ha−1 and soil carbon stock of 73.22 ± 39.40 t C ha−1. The average historical soil carbon sequestration rate of Kochi mangroves was also estimated as 2.95 t C ha−1 yr−1. The study revealed that there was significant variability in TECS and sediment carbon burial rate among riverine, estuarine and marine mangrove habitats and it appears that, the biological factors especially mangrove plant structure, species, age, litterfall production, crab density, mangrove conversion to aquaculture ponds and other urban pressure played major roles in driving the variability in carbon stocks and storage. While the sediment particle size, bulk density and the environmental settings played a secondary role. Very low TECS and soil carbon sequestration rate was found in aquaculture converted mangrove habitat. The CO2e of ecosystem carbon stock (496311.20 t CO2 e) and soil CO2 burial (10.62 t CO2 e ha−1 yr−1 respectively) of mangroves of Kochi, revealed that even with high urban pressure and anthropogenic activities which resulted in fragmented distribution, they are still potent in long term carbon sequestration unless it is not further disturbed. Therefore, conservation and restoration of mangrove habitats based on understanding of the regional controlling factors of carbon stock and carbon burial is a need for scientific climate change mitigation efforts. The study will also contribute to fill the gaps in global mangrove carbon stock assessments for avoiding uncertainties.

Korelasi indeks keanekaragaman dan kerapatan tegakan dengan simpanan karbon mangrove Estuari Perancak

Land use change is a huge threat for mangrove ecosystems,which are known for their high carbon sequestration and storage capacity.Vegetation restoration efforts are often undertaken, but fail to restore optimal ecosystem carbon sequestration. The mangrove forest of Perancak Estuary with a history of restoration project was made the subject of this research. The objectives include: (i) estimation of mangrove biomass and sediment carbon stock; (ii) comparison of restored, mixed and natural mangroves’ total carbon stock; (iii) correlational analysis between stand density and diversity indices with ecosystem carbon stock. Nine sampling points were determined within three mangrove categories (mixed, natural, restored). Stand characteristics and diameter at breast height (DBH) were measured to allometrically estimate biomass carbon. Sediment carbon was analyzed with Loss on Ignition (LOI) method. Correlational analysis was done with Pearson’s correlation coefficient. Total ecosystem carbon stock is 4472,93 tonnes ha-1 (biomass C: 4046,31 tonnes ha-1; sediment C: 426,62 tonnes ha-1). Highest carbon stock value was found on restored mangroves due to high contribution of sediment C offsetting its low biomass C. Lowest carbon stock value was found on natural mangroves due to decreased root biomass production and increased decomposition due to change in tidal regimes. There is a strong positive correlation between stand density and biomass carbon. Simpson index of diversity has a stronger (though non significant) correlation with biomass carbon than Shannon-Wiener index.

Belize Blue Carbon: Establishing a national carbon stock estimate for mangrove ecosystems

Mangrove ecosystems are among the most economically and ecologically valuable marine environments in the world. Mangroves are effective at long-term carbon storage within their sediments and are estimated to hold 12 billion metric tons of carbon worldwide. These ecosystems are therefore vitally important for carbon sequestration and, by extension, climate change mitigation. As part of the Paris Agreement, participating countries agree to provide plans to reduce their carbon emissions, or nationally determined contributions (NDCs). However, despite mangroves being recognized as important nature-based solutions, many countries still lack national data on carbon stocks and must use global or regional averages, which may not be sufficiently accurate. Here, we present the national carbon stock estimate of mangrove ecosystems for the NDC of Belize, acquired through a collaborative approach involving government agencies and NGOs. We conducted a comprehensive sampling of mangroves across the country, including a range of mangrove ecotypes. The mean total ecosystem carbon stock (TECS) for the nation was 444.1 ± 21.0 Mg C ha−1, with 74.4 ± 6.2 Mg C ha−1 in biomass stocks, and 369.7 ± 17.7 Mg C ha−1 in sediment stocks. Combining these data with a recent mapping effort, we provide the first national comprehensive mangrove carbon stock estimate of 25.7 Tg C. The national mean from this study varies from previous global analyses, which can under- or overestimate TECS by as much as 0.6 Tg C and 16.5 Tg C, respectively, depending on the study. These data supported the NDC update of Belize, and can be used to inform the country's mangrove protection and restoration commitments. The collaborative approach of this work should serve as a blueprint for other countries seeking to conserve natural blue carbon sinks as a strategy to achieve their climate targets.

Evaluation of Plant Growth and Potential of Carbon Storage in the Restored Mangrove of an Abandoned Pond in Lubuk Kertang, North Sumatra, Indonesia

Mangrove forest in Lubuk Kertang Village, West Brandan sub-district has been converted around 20 ha annually (1996–2016) into various non-forest land use. Rehabilitation can be a solution to restore the condition of the ecosystem so that it can resume its ecological and economic functions. This paper discusses the evaluation of mangrove rehabilitation carried out by planting 6000 propagules in December 2015 and 5000 seedlings in May 2016 with Rhizophora apiculata species in abandoned ponds. Monitoring was carried out every 6 months from 2016 to 2022. In the restored area, 11 true mangrove species and 3 associated mangrove species were found. The percentage of plants that survived after seven years was 69.42% for planting using propagules and 86.38% for planting with seedlings. The total biomass carbon stocks stored by 7-year-old plants using propagules was 51.18 Mg ha−1, while the carbon stored by planting using seedlings was 56.79 Mg ha−1. Soil carbon stocks at the planted site with propagules were 506.89 ± 250.74 MgC ha−1, and at the planted site with seedlings were 461.85 ± 102.23 MgC ha−1. The total ecosystem carbon stocks (including aboveground carbon) in the planted site using propagules were 558.07 MgC ha−1, while planting using seedlings were 518.64 MgC ha−1. The dataset and findings on the carbon storage evaluation of mangrove rehabilitation will be useful for blue carbon research community and policymakers in the context of the climate change mitigation strategy for Indonesia.

Blue carbon sinks in South Africa and the need for restoration to enhance carbon sequestration

Blue carbon ecosystems (mangroves, salt marshes, and seagrasses) contribute towards climate change mitigation because they are efficient at sequestering atmospheric CO2 into long-term total ecosystem carbon stocks. Destruction or disturbance therefore reduces sink capacity and leads to significant CO2 emissions. This study reports the first national estimates of: 1) total carbon storage, 2) CO2 emissions from anthropogenic activities, 3) the potential for restoration to enhance carbon sequestration for blue carbon ecosystems in South Africa. Mangrove ecosystems have the greatest carbon storage per unit area (253–534 Mg C ha−1), followed by salt marshes (100–199 Mg C ha−1) and seagrasses (45–144 Mg C ha−1). Salt marshes are the most extensive and contribute 67 % to the national carbon stock of 4000 Gg C. Since 1930, 6500 ha has been lost across all blue carbon ecosystems (26 % of the natural extent), equivalent to losing 1086 Gg C from the national carbon stock. Historic CO2 emissions were estimated at an average rate of 30,266 t CO2e yr−1. Despite losses, a total of 3998 ha could be restored to increase carbon sequestration and CO2 removals of 14,845 tCO2e.yr−1. Extractive activities have declined rapidly in recent decades, but abiotic pressures on estuarine ecosystems (flow modification, reduced water quality, and artificial breaching) have been increasing. There is an urgent need to quantify the potential impact of these pressures and include them in estuarine management and restoration plans. Blue carbon ecosystems cover a relatively small area in South Africa, but they are valued for their multiple ecosystem services that contribute towards climate change adaptation and biodiversity co-benefits. These ecosystems need to be included in national policies driving climate change response in the Agriculture, Forestry and Other Land-Use (AFOLU) sector, such as incorporating them into the wetland subcategory of the national GHG inventory.

Total ecosystem blue carbon stocks and sequestration potential along a naturally regenerated mangrove forest chronosequence

Naturally regenerated (NR) mangroves offer an excellent passive approach for climate change mitigation and adaptation under UN decade of restoration program. However, the support of NR mangroves on total ecosystem carbon (TEC) stocks and sequestration potential remained unclear across forest stand development process that can significantly vary spatially and temporally due to regeneration age. Using the ‘space for time’ approach, this study quantified the TEC stocks along the Merlimau - Kuala Sebatu fringing mangrove habitat expansion chrono-sequence that comprised of 3, 6, 12, 18, 25 years age and intact stands. We also estimated the carbon (C) sequestration potential of each stand-age by comparing with un-vegetated mudflats as control. We collected aboveground tree, belowground root, downed woody debris, litterfall and soil core up to 2 m for TEC quantification and C sequestration. Mean TEC stocks ranged from 232 ± 69 to 296 ± 49 Mg C/ha for NR3 and NR25 respectively at the study area. TEC stocks from different aged NR and intact mangroves were not significantly different from each other and therefore did not affect by age. Aboveground trees C and downed wood C pools were significantly affected by stand-age. In contrast, sediment C stocks (representing up to 80 %) remained generic over many years, driving the constant of TEC stocks in this study. Equally affected by age, the NR mangroves sequestered total C of 2.28 to 17.38 (mean ± SE: 7.36 ± 1.88 Mg C/ha yr−1), with younger stands (NR3) holding almost six times higher total C sequestration rates than older mangroves (NR25). Our study suggests that highly suspended sediments driving from upstream, especially in the younger mangrove stands at a lower elevation, supports higher bulk density and C accumulation rate in the sediment as they expand seaward. This study proves that NR mangroves comprised primarily of younger mangrove stands can be a C sequestrator powerhouse that promises nature-based climate solutions through avoidance and management. Though, future research is needed to understand how better management and conservation practices can affect or towards increasing trend of TEC especially sediment carbon stock that holds almost 80 % of total TEC.

Harvesting Intensity and Aridity Are More Important Than Climate Change in Affecting Future Carbon Stocks of Douglas-Fir Forests

Improved forest management may offer climate mitigation needed to hold warming to below 2°C. However, uncertainties persist about the effects of harvesting intensity on forest carbon sequestration, especially when considering interactions with regional climate and climate change. Here, we investigated the combined effects of harvesting intensity, climatic aridity, and climate change on carbon stocks in Douglas-fir [Pseudotsuga menziesii Mirb. (Franco)] stands. We used the Carbon Budget Model of the Canadian Forest Sector to simulate the harvest and regrowth of seven Douglas-fir stand types covering a 900 km-long climate gradient across British Columbia, Canada. In particular, we simulated stand growth under three regimes (+17%, −17% and historical growth increment) and used three temperature regimes [historical, representative concentration pathways (RCP) 2.6 and RCP 8.5]. Increasing harvesting intensity led to significant losses in total ecosystem carbon stocks 50 years post-harvest. Specifically, forests that underwent clearcutting were projected to stock about 36% less carbon by 2,069 than forests that were left untouched. Belowground carbon stocks 50 years into the future were less sensitive to harvesting intensity than aboveground carbon stocks and carbon losses were greater in arid interior Douglas-fir forests than in humid, more productive forests. In addition, growth multipliers and decay due to the RCP’s had little effect on total ecosystem carbon, but aboveground carbon declined by 7% (95% confidence interval [−10.98, −1.81]) in the high emissions (RCP8.5) scenario. We call attention to the implementation of low intensity harvesting systems to preserve aboveground forest carbon stocks until we have a more complete understanding of the impacts of climate change on British Columbia’s forests.

First assessment of the blue carbon storage of Rhizophora and Bruguiera mangrove stands on the island of Mauritius (western Indian Ocean)

Blue carbon has gained recognition as a strategy to mitigate climate change. Mangroves allow significant amounts of carbon to be sequestered and stored and are considered an important component in the offset of greenhouse gas emissions. Despite this, little is known about the ecosystem-level carbon storage of the mangrove stands of Mauritius, western Indian Ocean. We conducted an inventory of mangrove stands to characterise forest stand structure and estimate carbon stocks in terms of aboveground biomass and soil carbon at two sites, Ferney and Pointe d’Esny. Different allometric equations relative to species (for areas dominated by Rhizophora mucronata or Bruguiera gymnorrhiza) were used for aboveground biomass, and the loss-on-ignition method was used for estimating soil carbon. The results showed that aboveground biomass ranged from 54.57 Mg ha−1 to 328.71 Mg ha−1, and soil carbon from 99.11 ± 18.35 Mg ha−1 to 133.45 ± 30.35 Mg ha−1. The total ecosystem carbon stock ranged from 402.35 ± 19.29 Mg ha−1 to 427.81 ± 18.35 Mg ha−1 at Ferney, and from 188.03 ± 30.35 Mg ha−1 to 189.72 ± 19.27 Mg ha−1 at Pointe d’Esny. Our results underscore the importance of mangrove forest stands and highlight the need for in-depth and broader spatial-scope research on blue carbon ecosystems in Mauritius.

Integrating Economic Value of Environmental Services and Carbon Stock: A Case Study from Bogani Nani Wartabone National Park

As a conservation area, national parks play essential roles in environmental services provision and have the potential to support the REDD+ program. This study aims to estimate appropriate incentives for national parks based on carbon units by integrating the economic value of environmental services and carbon stock provided by the lowland dry forest ecosystem in Bogani Nani Wartabone National Park (BNWNP) consisted of North Sulawesi and Gorontalo areas. Carbon stock was estimated by establishing sample plots, including five carbon pools. While the economic valuation of environmental services includes biodiversity using the market approach, ecotourism using the zonal travel cost method, and water service using simulation water regulation services method and market approach. The total ecosystem carbon stock in BNWNP is estimated at 73.67 Mton. Meanwhile, the estimation of the economic value of environmental services is about IDR 70.57 trillion. Based on these results, the appropriate carbon values are IDR 683,308 and IDR 1,304,238 per ton carbon for the lowland dry forest ecosystem in Gorontalo and North Sulawesi areas. This result indicates that given its essential environmental services, the incentive for protecting national parks may exceed the carbon value used in result-based payment scheme in REDD+ initiatives that have been implemented.

Total Ecosystem Carbon Stocks of Mangroves in Lamu, Kenya; and Their Potential Contributions to the Climate Change Agenda in the Country

Mangroves are carbon-rich ecosystems found in tropical and subtropical areas around the world. However, they are threatened by a combination of natural and human-induced factors. When mangroves are lost or degraded, their co-benefits to human society are greatly diminished along with the ecosystem’s ability to sequester carbon. The current study assessed mangrove cover and cover change, as well as measuring carbon stocks and their emissions levels from the mangroves of Lamu County, Kenya. We sampled above-and below-ground carbon pools, including soil organic carbon (SOC), in 191 plots distributed throughout the study area. Lastly, we evaluated the economics of avoiding mangrove deforestation based on the carbon-offset market. The total carbon stock of mangroves in Lamu was estimated at 20 million Mg C, with an average density of 560.22 ± 79.79 Mg C ha–1. Southern swamps recorded significantly higher carbon densities (p &amp;lt; 0.05) than other mangrove management blocks in Lamu. At least 1,739 ha of mangroves in Lamu were lost between 1990 and 2019 due to anthropogenic activities, representing a decline of 60 ha yr–1. Total emissions from loss and degradation of mangroves in Lamu is estimated at 140.1 Mg C ha–1; which translates to 30,840.1 Mg CO2e yr–1. Assuming an offset price of US$10/Mg CO2e, the estimated costs of avoided emissions in Lamu is US$308,401 yr–1 plus other co-benefits such as fishery functions and shoreline protection. Mainstreaming mangroves and associated blue carbon ecosystems into national development and climate change agenda could accelerate Kenya’s achievements of both Sustainable Development Goals (SDGs) and the Paris Agreement.