Biomass Carbon Storage Research Articles

Scaling up climate ambition post-2030: a long-term GHG mitigation analysis for Thailand

ABSTRACT Thailand’s Nationally Determined Contribution (NDC) submitted to the United Nations Framework Convention on Climate Change (UNFCCC) aims to reduce 20 to 25% of greenhouse gas (GHG) emissions with respect to the projected reference level of NDC in 2030, respectively, in its unconditional and conditional scenarios. The Intergovernmental Panel on Climate Change (IPCC) states that limiting global temperature rise to 1.5°C would require net zero carbon dioxide emissions globally by around 2050. Thailand’s current energy system is highly fossil fuel dependent and requires enormous transformations to achieve more stringent GHG emission reduction targets beyond its NDC. This paper seeks to estimate the level and the intensities of Thailand’s energy system and their economy-wide effects post-2030 under the business as usual and 16 GHG emission reduction scenarios ranging from 30 to 100% by 2050. A computable general equilibrium analysis using the AIM/Hub model is employed to estimate the macroeconomic impacts of meeting the unconditional and conditional emission reductions of Thailand’s NDC in 2030 along with varying GHG emission reductions in 2050. Results show that renewables – constituting solar, wind, biomass and hydro and carbon capture and storage (CCS) technologies account for more than 95% in the power generation mix by 2050, if 100% GHG emission reduction from the 2010 level is to be achieved. Electricity generation based on biomass both with and without CCS will occupy a major share in the investments by 2050 in all the conditional and unconditional NDC scenarios. A rapid increase in carbon sequestration occurs from 2040 onwards through the deployment of CCS and bioenergy with CCS (BECCS) technologies in all the conditional and unconditional NDC scenarios. Carbon prices lie in the range of 3.4–266.2 US$/tCO2eq during 2025–2050 to achieve 100% GHG emission reductions in 2050. Imposition of early stringent mitigation target lowers the carbon prices in the conditional scenarios towards 2050 when compared to the unconditional scenarios. The rapid uptake of CCS, energy efficiency improvements and electrification of the end-use technologies are identified to be the key measures to transform the energy system of Thailand. Key policy insights By 2050, the Thai economy would face a higher fall in both the GDP and household consumption in the unconditional scenarios than those in the conditional scenarios at all levels of GHG emission reduction. Results indicate that early mitigation efforts can be less costly than the delayed ones in the long-term. The cumulative investment needed to achieve decarbonization in Thailand is estimated to exceed 355 billion US$2005 over the period 2010–2050 in the 100% GHG reduction scenarios. The transmission and distribution investments in the power sector need to increase by 30–35% to attain 100% GHG emission reductions during 2010–2050. The trade deficit improves by up to 23–29% in the various GHG mitigation scenarios in 2050.

Carbon stocks and changes in biomass of Mediterranean woody crops over a six-year period in NE Spain

Carbon sequestration and storage in biomass is one of the most important measures to mitigate climate change. Mediterranean woody crops can sequestrate carbon in the biomass of their permanent structures for decades; however, very few studies have focused on an assessment of biomass and carbon sequestration in these types of crops. This study is the first to estimate above- and belowground biomass carbon stock in Mediterranean woody crops through a bottom-up approach in the NE Iberian Peninsula in 2013. Moreover, this is the first time that an assessment of the annual changes in carbon stock in the study area over a six-year period is presented. For this purpose, eight crop- and site-specific equations relating biomass or biometric variables to crop age were calculated. Most of the data were our own measurements, but unpublished data supplied from other authors as well as data from literature were also considered. Census of Agriculture data was used to scale results from individual data up to the municipality level at the regional scale. Results show that in woody cropland in NE Spain the total biomass carbon stock in 2013 was 5.48 Tg C, with an average value of 16.44 ± 0.18 Mg C ha−1. Between 2013 and 2019, although there was a 2.8% mean annual decrease in the area covered by woody crops, the carbon stock in the biomass of these crops increased annually by 3.8% due to the growth of the remaining woody cropland. This new estimation of carbon stocks may contribute to better understand carbon balances and serve as a baseline to global inventories. It may also serve to assess and manage carbon storage as an ecosystem service provided by Mediterranean woody cropland for mitigating climate change and, in combination with adaptive strategies, for supporting a productive and resilient agro-food system.

Alpine shrub growth follows bimodal seasonal patterns across biomes – unexpected environmental controls

Under climate change, cold-adapted alpine ecosystems are turning into hotspots of warming. However, the complexity of driving forces of growth, associated biomass gain and carbon storage of alpine shrubs is poorly understood. We monitored alpine growth mechanisms of six common shrub species across contrasting biomes, Mediterranean and tundra, using 257 dendrometers, recording stem diameter variability at high temporal resolution. Linking shrub growth to on-site environmental conditions, we modelled intra-annual growth patterns based on distributed lag non-linear models implemented with generalized additive models. We found pronounced bimodal growth patterns across biomes, and counterintuitively, within the cold-adapted biome, moisture, and within the drought-adapted biome, temperature was crucial, with unexpected consequences. In a warmer world, the Mediterranean alpine might experience strong vegetation shifts, biomass gain and greening, while the alpine tundra might see less changes in vegetation patterns, minor modifications of biomass stocks and rather browning.

Sequestration of carbon in commercial plantations and farm forestry

Commercial plantations and farm forestry have the potential to increase the average carbon storage in woody biomass through afforestation, integration of belt plantings into farms, or increasing the average length of harvest rotations. In Australia, such increases in carbon storage are estimated at national- and project-scale through application of the stand-level carbon accounting model FullCAM, with predictions predominantly influenced by an input layer of biomass potential and calibrated yield curve parameters. Recent revision of the biomass potential input layer in FullCAM necessitated a refinement of yield curve calibrations for plantations and farm forestry, and therefore provided an opportunity to expand the capability of the model. Here we collated and analysed 16,749 observations of yields of above-ground biomass (AGB, Mg DM ha−1) from 8,749 independent plantation stands to assess whether growth differed between regions, species, management regimes and planting configurations and inform grouping of calibration sites into 17 different categories of tree plantings across Australia, with each having unique yield curve calibrations. Eight of the categories comprised species (or hybrids) that are commonly established in Australia, while other species (for which there were less AGB data) were grouped into generic multi-species categories based on plant functional type and/or planting configuration (block or belt). In revising the model calibrations, the trade-off between model accuracy and utility was considered. Across all plantation categories, stand age and biomass potential alone explained an average of 60% of the variation in observed AGB, with little (<10%) additional variation explained by factors such as region, species in the multi-species categories, or whether considering differences in yields from new plantings vs. regrowth post coppice harvesting. Although predictions were unbiased overall, they may nonetheless provide erroneous predictions at a given site. Although individual over- and under-predictions will tend to cancel out for carbon accounting at the national-scale, at the project-scale where carbon offsets are monetarised, discounting for uncertainty may be implemented.

The global potential for increased storage of carbon on land

Constraining the climate crisis requires urgent action to reduce anthropogenic emissions while simultaneously removing carbon dioxide from the atmosphere. Improved information about the maximum magnitude and spatial distribution of opportunities for additional land-based removals of CO2 is needed to guide on-the-ground decision-making about where to implement climate change mitigation strategies. Here, we present a globally consistent spatial dataset (approximately 500-m resolution) of current, potential, and unrealized potential carbon storage in woody plant biomass and soil organic matter. We also provide a framework for prioritizing actions related to the restoration, management, and maintenance of woody carbon stocks and associated soils. By comparing current to potential carbon storage, while excluding areas critical to food production and human habitation, we find 287 petagrams (PgC) of unrealized potential storage opportunity, of which 78% (224 PgC) is in biomass and 22% (63 PgC) is in soil. Improved management of existing forests may offer nearly three-fourths (206 PgC) of the total unrealized potential, with the majority (71%) concentrated in tropical ecosystems. However, climate change is a source of considerable uncertainty. While additional research is needed to understand the impact of natural disturbances and biophysical feedbacks, we project that the potential for additional carbon storage in woody biomass will increase (+17%) by 2050 despite projected decreases (−12%) in the tropics. Our results establish an absolute reference point and conceptual framework for national and jurisdictional prioritization of locations and actions to increase land-based carbon storage.

The Carbon Neutral Potential of Forests in the Yangtze River Economic Belt of China

Prediction of forest carbon sink in the future is important for understanding mechanisms concerning the increase in carbon sinks and emission reduction, and for realizing the climate goals of the Paris Agreement and global carbon neutrality. Based on stand volume data of permanent monitoring plots of the successive national forest inventories from 2004 to 2018, and combined with multiple variables, such as climatic factors, soil properties, stand attributes, and topographic features, the random forest algorithm was used to predict the stand volume growth-loss and then calculated the forest biomass and its carbon sink potential between 2015 to 2060 in the Yangtze River Economic Belt of China. From 2015 to 2060, the predicted forest biomass carbon storage and density increased from 3053.27 to 6721.61 Tg C and from 33.75 to 66.12 Mg C hm−2, respectively. The predicted forest biomass carbon sink decreased from 90.58 to 73.98 Tg C yr−1, and the average forest biomass carbon storage and sink were ranked in descending order: Yunnan, Sichuan, Jiangxi, Hunan, Guizhou, Hubei, Zhejiang, Chongqing, Anhui, Jiangsu, and Shanghai. The forest biomass carbon storage in the Yangtze River Economic Belt will increase by 3.67 Pg C from 2015 to 2060. The proportion of forest C sinks on the regional scale to C emissions on the national scale will increase from 2.9% in 2021–2030 to 4.3% in 2041–2050. These results indicate higher forest carbon sequestration efficiency in the Yangtze River Economic Belt in the future. Our results also suggest that improved forest management in the upper and middle reaches of the Yangtze River will help to enhance forest carbon sink in the future.

Tree diversity and carbon important species vary with traditional agroforestry managers in the Indian Eastern Himalayan region.

Traditional agroforestry systems, one of the time tested and dominant land use from tropical to sub-tropical regions, were recognized for their contributions to food production, biodiversity conservation, and atmospheric carbon sequestration. Their management often varies from region to region. However, these systems frequently mimic economically managed land uses due to increased pressure on the monetary requirement of their managers. The present study aims to evaluate (i) tree density, (ii) tree diversity indices, and (iii) identify the biomass carbon important tree species managed by different communities of the Indian Eastern Himalayan region. We found that the Mizo community harbored the highest number of tree species (35) in the traditional agroforestry system with the highest tree diversity index (3.47). Total biomass carbon of tropical agroforestry systems managed by different communities ranged between 4.72Mgha-1 (Meitei) and 29.26Mgha-1 (Bengali). Similarly, in the sub-tropical traditional agroforestry system, the highest and the lowest biomass carbon was observed in Mizo- (10.93Mgha-1) and Angami- (6.05Mgha-1) managed systems. Of the 31 biomass carbon, important species found across the traditional agroforestry systems,Artocarpus heterophyllus, had the highest occurrence (50%), followed byParkia timoriana(37.5) andAmoora rohituka,Delonix regia,Mangifera indica,andToona ciliata(25% for each species). Farmers' preference to cash return of a species, trees density, and basal area were the determinant factors in the carbon stock potential of these systems. The present study suggests that the farmers' preferred and dominant species in their agroecosystems have a limited scope of enhanced biomass carbon storage. Therefore, improvement of traditional agroforestry systems through selective incorporation of biomass carbon important tree species is recommended to enhance the carbon sink capacity of these systems.

Integration of supply chain management of hybrid biomass power plant with carbon capture and storage operation

Bioenergy Carbon Capture and Storage (BECCS) is thought to be one of the most important technologies to realize the deep carbon emission reduction. An integrated model that combines biomass inventory management and carbon capture and storage (CCS) construction is built to analyze the operation management of BECCS plants. Biomass supply level and structure, operation costs, warehousing scale, and application restrictions are considered in the inventory management. The operation costs, learning effects, investment path, and capture efficiency of CCS are considered in the process of CCS construction. These two processes are integrated to maximize the total profit for biomass power plants under inter-temporal conditions. Jiangsu Province is selected for numerical simulation. The results show that the supply level of biomass has a great influence on the results, and the corresponding CCS technology needs to fully consider this factor for expansion. In addition, under strict carbon emission constraints, to avoid the high cost of CCS, policymakers are more inclined to achieve emission reduction targets by reducing power generation levels. Therefore, appropriate policy subsidies are needed to ensure the development of BECCS at this time.

Aboveground carbon responses to experimental and natural hurricane impacts in a subtropical wet forest in Puerto Rico

AbstractClimate change and disturbance make it difficult to project long‐term patterns of carbon sequestration in tropical forests, but large ecosystem experiments in these forests can inform predictions. The Canopy Trimming Experiment (CTE) manipulates two key components of hurricane disturbance, canopy openness and detritus deposition, in a tropical forest in Puerto Rico. We documented how the CTE and a real hurricane affected tree recruitment, biomass, and aboveground carbon storage over 15 years. In the CTE treatments, we trimmed branches, but we did not fell trees. We expected that during the 14‐year period after initial canopy trimming, regrowth of branches and stems and stem recruitment stimulated by increased light and trimmed debris would help restore biomass and carbon loss due to trimming. Compared to control plots, in the trimmed plots recruitment of palms and dicot trees increased markedly after trimming, and stem diameters of standing trees increased. Data showed that recruitment of small trees adds little to aboveground carbon, compared to the amount in large trees. Nevertheless, this response restored pretreatment biomass and carbon in the experimental period. In particular, the experimental additions of trimmed debris on the forest floor seemed to stimulate increase in aboveground carbon. Toward the end of the experimental period, Hurricane Maria (Category 4 hurricane) trimmed and felled some trees but reduced aboveground carbon less in the plots (including untrimmed plots) than experimental trimming had. Thus, it appears that the amount of regrowth recorded after experimental trimming could also restore aboveground carbon in the forest after a severe hurricane in the same time span. However, Hurricane Maria, unlike the trimming treatments, felled large trees, and it may be that with predicted, more frequent severe hurricanes, that the continued loss of large trees would over the long term decrease aboveground carbon stored in this Puerto Rican forest and likewise in other tropical forests affected by cyclonic storms.

Carbon Storage in Biomass and Soil after Mountain Landscape Restoration: Pinus nigra and Picea abies Plantations in the Hyrcanian Region

Forest plantations have significantly more potential for carbon storage than non-forested areas. In this study, the amount of carbon stored in the biomass (trees, shrubs, herb, litter, and deadwood) and soil of 25-year-old plantations with P. nigra and P. abies species was measured and compared with the non-planted adjacent area (control) in a mountainous region of northern Iran. The results show that the amount of carbon stored in the biomass of P. nigra and P. abies plantations was 4.4 and 3.3 times higher than the value of the control (4.59 C Mg ha−1), respectively. In addition, the amount of carbon stored in soil was 1.5 and 1.2 times higher than the value at the control site (47.91 C Mg ha−1), respectively. Of the total carbon stored in the biomass of plantations, the highest level was observed in trees (86.5–88.5%), followed by shrubs (4.6–6.5%), litter (2.7–2.8%), the herbaceous layer (1.8–2.5%), and deadwood (1.7–2.4%), while 45.5%, 34.6%, 10.8%, 5.8%, and 3.3% of the total carbon stored in the biomass of the control site were in shrubs, trees, the herbaceous layer, litter, and deadwood, respectively. The soil carbon sequestration rate (SCSR) in soil depths of 0–10 and 10–20 cm was 0.46 and 0.44 C Mg ha−1 yr−1 in the P. nigra plantation and 0.15 and 0.23 C Mg ha−1 yr−1 in the P. abies plantation, respectively. According to the results, we conclude that the restoration of the landscape by tree plantation has a substantially determining impact on the acceleration of carbon sequestration.

Blue carbon storage in Fijian seagrass meadows: First insights into carbon, nitrogen and phosphorus content from a tropical southwest Pacific Island

Seagrasses provide vital ecosystem services which include the accumulation and storage of carbon and nutrients in sediments and biomass. Despite their importance in climate change mitigation and adaptation, seagrass ecosystems have been poorly studied, particularly in the Pacific. Therefore, the present study assessed variability in sedimentary and vegetative C, N and P storage in three monospecific seagrass meadows (Halophila ovalis, Halodule pinifolia and Halodule uninervis), reporting baseline data for the first time. Sediment Corg stocks ranged from 31 to 47 Mg C ha−1 and varied (p < 0.001) between seagrass meadows, unvegetated areas and locations. Comparison of N and P storage between vegetated meadows and unvegetated areas revealed differences (p < 0.05); implying seagrass meadows function as C, N and P sinks. Differences in species composition and environmental conditions, may play a key role in estimating C, N and P stocks, which are valuable data for conservation and monitoring of seagrass ecosystems.

Plant phosphorus-use and -acquisition strategies in Amazonia.

In the tropical rainforest of Amazonia, phosphorus (P) is one of the main nutrients controlling forest dynamics, but its effects on the future of the forest biomass carbon (C) storage under elevated atmospheric CO2 concentrations remain uncertain. Soils in vast areas of Amazonia are P-impoverished, and little is known about the variation or plasticity in plant P-use and -acquisition strategies across space and time, hampering the accuracy of projections in vegetation models. Here, we synthesize current knowledge of leaf P resorption, fine-root P foraging, arbuscular mycorrhizal symbioses, and root acid phosphatase and organic acid exudation and discuss how these strategies vary with soil P concentrations and in response to elevated atmospheric CO2 . We identify knowledge gaps and suggest ways forward to fill those gaps. Additionally, we propose a conceptual framework for the variations in plant P-use and -acquisition strategies along soil P gradients of Amazonia. We suggest that in soils with intermediate to high P concentrations, at the plant community level, investments are primarily directed to P foraging strategies via roots and arbuscular mycorrhizas, whereas in soils with intermediate to low P concentrations, investments shift to prioritize leaf P resorption and mining strategies via phosphatases and organic acids.

Allometric Equation for Aboveground Biomass Estimation of Mixed Mature Mangrove Forest

The disturbance of mangrove forests could affect climate regulation, hydrological cycles, biodiversity, and many other unique ecological functions and services. Proper biomass estimation and carbon storage potential are needed to improve forest reference on biomass accumulation. The establishment of a site-specific allometric equation is crucial to avert destructive sampling in future biomass estimation. This study aimed to develop a site-specific allometric equation for biomass estimation of a mix-mature mangrove forest at Sungai Pulai Forest Reserve, Johor. A stratified line transect was set up and a total of 1000 standing trees encompassing seven mangrove tree species were inventoried. Destructive sampling was conducted using the selective random sampling method on 15 standing trees. Five allometric equations were derived by using diameter at breast height (D), stem height (H), and wood density (ρ) which were then compared to the common equation. Simulations of each allometric equation regarding species were performed on 1000 standing trees. Results showed that the single variable (D) equation provided an accurate estimation, which was slightly improved when incorporated with the H variable. Both D and H variables, however, gave inconsistent results for large-scale data and imbalance of sampled species. Meanwhile, the best fit either for small-scale or large-scale data, as well as for imbalanced sample species was achieved following the inclusion of the ρ variable when developing the equation. Hence, excluding the H variable while including the ρ variable should be considered as an important determinant in mixed mangrove species and uneven-aged stand for aboveground biomass estimation. This valuation can both improve and influence decision-making in forest development and conservation.

Temporal dynamics of carbon storage in a Mediterranean mountain scrubland managed by prescribed fire

Farmland abandonment and reduction of grazing activity, mainly in mountain areas with remote access and ageing population, have been contributing to shrub encroachment in such territories and, consequently, to increase fuel load available for triggering wildfires. Accordingly, it is necessary to use vegetation management practices in order to reduce wildfire risk, prescribed fire being one of the most common techniques used in the Mediterranean region. This research focused in the effects of a prescribed fire (PF) applied in Montesinho Natural Park (PNM), NE Portugal, on the temporal dynamics of carbon storage in mineral soil, litter layer (organic horizon), and shrub biomass. Before PF and thirty-six months after PF, aboveground shrub biomass was collected in areas of 1 m2 in 11 plots randomly distributed in the experimental shrub area. Also, in the same plots, litter thickness was measured and soil samples were collected before, two, six and thirty-six months after PF, in order to assess carbon concentration, bulk density and coarse elements content. Despite low to moderate fire intensity, carbon storage changes were observed in all compartments evaluated. Thirty-six months after PF, carbon storage in aboveground biomass of shrub species (7.4 Mg C ha−1) was roughly two-thirds of that recorded prior to PF, and in litter layer (1.6 Mg C ha−1) it was about half of that in the original situation (before PF). In contrast, the mineral soil showed a 10% carbon increase (6.4 Mg C ha−1). Based on the balance between losses (shrub species and litter layer) and gains (mineral soil), at the end of the monitoring period (36 months), there was an annual positive rate of carbon storage, equivalent to 0.2 Mg C ha−1 year−1. Even after anthropogenic disturbances, such as prescribed fire, shrub communities constitute important terrestrial carbon pools; hence, these ecosystems might play an important role in mitigating climate change.

Are northern German Scots pine plantations climate smart? The impact of large-scale conifer planting on climate, soil and the water cycle

Increasing temperatures and rising atmospheric vapor pressure deficits are exposing forests around the globe to increasing drought and heat stress, demanding a shift to climate-smart forestry for increasing the stress resistance and resilience of production forests and to enhance their climate change mitigation potential. Based on measurements in paired pine and beech forests and the review of literature data, we analyse the biophysical consequences and the carbon cycle impact of large-scale Scots pine (Pinus sylvestris L.) plantations in northern Germany in the face of a warming and aridifying climate. We quantified canopy surface albedo and surface temperature, evapotranspiration and deep seepage, carbon (C) storage in biomass and soil and annual C sequestration, and soil acidification of pine plantations in comparison to beech forests (Fagus sylvatica L.), the natural forest vegetation. We find that near-infrared (NIR, 700–3000 mn) canopy surface albedo is higher by 5.2 percentage points during summer over beech as compared to pine forest, resulting in a 9 % higher net radiation and a 0.6 K higher surface temperature of the pine canopy. Deep seepage is on average by 68 mm yr−1 smaller under pine than beech forest (66 mm yr−1 vs. 134 mm yr−1) due to the higher evapotranspiration of pine. C storage in biomass and soil is by ∼ 48 Mg C ha−1 higher in beech than pine forests, reflecting the higher productivity of beech, demonstrating an unfavorably low C sequestration potential of Scots pine plantations. We conclude that the large-scale Scots pine plantations in northern Germany (>1.7 million ha) are neither environmental-friendly nor climate smart, given their enhancement of climate-warming, low climate change mitigation potential, and negative effect on groundwater recharge. Replacing pine plantations by beech (or other hardwood) forests in northern Germany and adjacent regions is urgently needed for achieving the goals of climate-smart forestry.

Impacts of Site Conditions and Stand Structure on the Biomass Allocation of Single Trees in Larch Plantations of Liupan Mountains of Northwest China

Understanding the determinants of tree biomass allocation patterns among organs is crucial for both predicting the rate and potential of forest carbon sinks and guiding future multifunctional forest management. However, it is still not clear how the site conditions (e.g., elevation) and stand structure (e.g., tree dominance, stand density) affect the biomass allocation of single trees in forests. This study was implemented in the Liupan Mountains of the Loess Plateau of Northwest China by collecting the related information of biomass data of 110 sample trees with different dominance and influencing factors within 23 sample plots of larch plantations set up along the elevation gradient. Based on these data, the response tendency and functions of biomass allocation of single trees to individual influencing factors of site conditions and forest structure were analyzed. Moreover, the results illustrated that the ratio between root biomass and aboveground biomass decreased significantly with rising stand age and tree density, but increased significantly with rising elevation, and there was no significant relationship with the dominance of individual trees. The results of this study revealed the importance of considering the influencing factors of site conditions and stand structure when developing dynamic models of tree biomass allocation. The results and research methods used in this study provide useful tools for quantifying the biomass allocation and carbon storage partitioning in the study area and other similar regions.

Preliminary Estimation of Soil Carbon Sequestration of China's Forests during 1999–2008

The National Forest Inventory (NFI) is an important resource for estimating the national carbon balance (These data were unpublished data, and we could only obtain the data before 2008 through data search by now). Based on the data from sample plots, the literature, and NFI, as well as the relationships between volume, biomass, annual litterfall and soil respiration of different forest types, the net ecosystem production (NEP), changes in forest biomass carbon storage (ΔCbiomass) and non-respiratory losses (NR) of China's forests during 1999–2008 were estimated, and the forest soil carbon sequestration (ΔCsoil) was assessed according to the carbon balance principle of the forest ecosystem (ΔCsoil = NEP – NR – ΔCbiomass). The results showed that the total NEP, ΔCbiomass, NR and ΔCsoil values for China's forests were 157.530, 48.704, 31.033 and 77.793 Tg C yr–1 respectively, and average NEP, ΔCbiomass, NR, and ΔCsoil values were 101.247, 31.303, 19.945 and 49.999 g C m–2 yr–1 respectively. There were large spatial differences in forest soil carbon sequestration in different parts of China. The forest soil in Jiangxi, Hunan, Zhejiang, Fujian, Anhui, Shanxi, Shaanxi, Guangxi and Liaoning served as carbon sources and the carbon released was about 25.507 Tg C yr–1. The other 22 provinces served as carbon sinks and the average carbon sequestration by forest soil came to 103.300 Tg C yr–1. This research established a method for evaluating soil carbon sequestration by China's forests based on the NFI, which is a useful supplement to current statistical data-based studies on the forest ecosystem carbon cycle, and can promote comparable studies on forest soil carbon sequestration with consistent research methods at the regional scale.

Ecological roles and importance of sea cows (Order: Sirenia): a review and prospectus

Sirenians (manatees Trichechus spp. and the dugong Dugong dugon) are large-bodied and almost exclusively herbivorous aquatic mammals occurring in coastal and freshwater habitats of most tropical and subtropical regions. Although sirenian ecology, habitat use, and abundance have been investigated across their range, little is known about the roles and impacts of these megaherbivores outside of the trophic relationships of 2 relatively well-studied species (T. manatus, D. dugon). This knowledge gap limits our understanding of how sirenians affect communities and ecosystem dynamics. We review the literature on the ecological roles and importance of sirenians in aquatic ecosystems, including the extinct Steller’s sea cow Hydrodamalis gigas. Our review reveals that sirenian herbivory and disturbance can markedly affect species biomass, productivity, and composition in macrophyte communities, thereby indirectly influencing other community members (e.g. invertebrates) and carbon storage in macrophyte biomass and sediments. Sirenians may also couple disparate ecosystems via their movements, compete with other herbivores, and serve as prey for, and be responsive to, predators, including humans. We also identify key knowledge gaps, including (1) the ecology of Amazonian T. inunguis and African T. senegalensis manatees, (2) experimental investigations of the magnitude of trophic impacts and their potential to cascade to other species and carbon dynamics, (3) the roles and impacts of sirenians as omnivores, and (4) the non-consumptive effects of predators on sirenians other than dugongs. Finally, we highlight crucial avenues for future sirenian research, including changes to their ecology in the face of ongoing seagrass declines and climate change.

长江经济带林地和其他生物质碳储量及碳汇量研究

长江经济带林地和其他生物质碳储量及碳汇量研究

Soil Properties, Litter Dynamics and Biomass Carbon Storage in Three-Bamboo Species of Sub-Himalayan Region of Eastern India

Soil Properties, Litter Dynamics and Biomass Carbon Storage in Three-Bamboo Species of Sub-Himalayan Region of Eastern India