Tree Carbon Sequestration Research Articles

Dynamics of standing dead wood and severe fire in north Australian savannas: implications for carbon management

Background Many fires in north Australian savannas are severe enough to cause canopy scorch, tree death and removal of stags. Better fire management may increase carbon sequestration in trees, perhaps including stags. Aims To describe and analyse dynamics of stags in tropical savannas (600–1000 mm annual rainfall) in relation to fire and better understand their role in biomass sequestration. Methods We monitored marked populations of live and dead trees over 12 years. Statistical models describing influences on stag creation and loss are applied in stag dynamics simulations. Key results Immediately following severe fire, stag biomass increases acutely because many more live trees are killed than stags removed. Between severe fires, stag losses exceed tree deaths, so peaks are quite short. Many ‘new’ stags are lost (fallen or consumed) quickly. Conclusions Between fires, stags comprise ~7.5–8.9% of standing above-ground biomass, more under dry conditions and during recovery from severe fire or other drivers of increased tree mortality. Fire management is unlikely to increase proportions of total woody biomass in stags unless it also reduces live biomass. Implications Reducing frequency of severe fires can increase total carbon sequestration in dry tropical savannas. Prediction uncertainties and management risks around sequestration present daunting challenges for policy-makers and fire management practitioners.

VISUAL TREE ASSESSMENT AND ESTIMATION OF TREE CARBON SEQUESTRATION FOR OUTDOOR STUDENT CENTRE

Environmental assessment is crucial for every project development, especially when the space is surrounded by many mature trees. Failing to understand the existing character and conditions of the site can result in design failures that may lead to the loss of ecosystem benefits. Many developments are constructed without consulting experts, leading to unstructured development. Therefore, this research aims to investigate the potential of a proposed outdoor space towards a better teaching and learning environment. This study analyses Visual Tree Assessment (VTA) and estimates the carbon sequestration of trees using qualitative and quantitative data. The objectives are to create a topographic layout map by assessing site conditions, examining tree species and their condition through limited VTA, and estimating the net carbon sequestration of the on-site trees. 59 trees were analysed, and a map was developed for overlay purposes. A composite map illustrates the correlation of comfort, movement, aesthetics, and social relations criteria for the Outdoor Student Centres. In conclusion, 82% of Pongamia pinnata trees are deemed unsuitable for the site and may be considered for removal for OSC development. The site's net tree carbon sequestration is estimated to sequester a minimum of 611 kg of carbon. Effective site planning is a crucial factor in this process to ensure optimal outcomes.

Carbon Sequestration of Common Garden Tree Species under the Carbon Neutrality Target in East China

The global warming phenomenon caused by greenhouse gas emission leads to the deterioration of the ecological environment. In urban spaces, the selection of garden tree species with high carbon sequestration rates can effectively contribute to carbon neutrality. In this study, we measured the height, diameter at breast height, and crown width of 643 ancient trees around the West Lake Scenic Spot, Hangzhou, China, and recorded their species and ages. By the biomass expansion factor method, the long-term carbon sequestration of the trees was calculated, and the corresponding statistical analysis indicated the following findings: (1) The maximum carbon sequestration of ancient trees varies with the species; the simple rational function has the best fit for the relationship between mean annual carbon sequestration and age. (2) For the five most common species in the Hangzhou area, the total individual amount of carbon sequestration per tree species can be ranked from high to low as follows: Celtis julianae, Cinnamomum camphora, Castanopsis sclerophylla, Liquidambar formosana, and Ginkgo biloba (tree age < 260 years). The ranking for trees aged above 260 years is as follows: Celtis julianae, Cinnamomum camphora, Liquidambar formosana, Castanopsis sclerophylla, and Ginkgo biloba. (3) The transient and mean annual carbon sequestration rate decreases as tree age increases; for most of the ancient trees in this research, the main growing period is 0–300 years. (4) Castanopsis sclerophylla, Liquidambar Formosana, and Osmanthus fragrans are recommended for urban landscape greening as they provide continuous long-term carbon sequestration and special landscape features.

Current inequality and future potential of US urban tree cover for reducing heat-related health impacts

Excessive heat is a major and growing risk for urban residents. Here, we estimate the inequality in summertime heat-related mortality, morbidity, and electricity consumption across 5723 US municipalities and other places, housing 180 million people during the 2020 census. On average, trees in majority non-Hispanic white neighborhoods cool the air by 0.19 ± 0.05 °C more than in POC neighborhoods, leading annually to trees in white neighborhoods helping prevent 190 ± 139 more deaths, 30,131 ± 10,406 more doctors’ visits, and 1.4 ± 0.5 terawatt-hours (TWhr) more electricity consumption than in POC neighborhoods. We estimate that an ambitious reforestation program would require 1.2 billion trees and reduce population-weighted average summer temperatures by an additional 0.38 ± 0.01 °C. This temperature reduction would reduce annual heat-related mortality by an additional 464 ± 89 people, annual heat-related morbidity by 80,785 ± 6110 cases, and annual electricity consumption by 4.3 ± 0.2 TWhr, while increasing annual carbon sequestration in trees by 23.7 ± 1.2 MtCO2e yr−1 and decreasing annual electricity-related GHG emissions by 2.1 ± 0.2 MtCO2e yr−1. The total economic value of these benefits, including the value of carbon sequestration and avoided emissions, would be USD 9.6 ± 0.5 billion, although in many neighborhoods the cost of planting and maintaining trees to achieve this increased tree cover would exceed these benefits. The exception is areas that currently have less tree cover, often the majority POC, which tend to have a relatively high return on investment from tree planting.

Influence of Irrigation on Biomass Partitioning in Above- and Belowground Organs of Trees Planted in Desert Sites of Mongolia

Planting trees is considered a crucial factor in mitigating the increase in carbon emissions in the atmosphere by generating plant biomass. In addition to advancing our understanding of how tree biomass is allocated in desert environments, we explore potential variations in biomass partitioning based on the irrigation regimes (4, 8, and 12 L h−1) supporting the growth of these trees. Specifically, this study compares the pattern of biomass distribution between above-ground and belowground organs of 11-year-old trees (U. pumila, E. moorcroftii, and T. ramosissima) planted in a desert site in Mongolia. An interesting result of this study is the demonstration that biomass partitioning among roots of different diameter classes differs between the tree species tested, suggesting that each tree species establishes its own type of root/soil interaction. The differences in biomass partitioning in roots could determine specificity in the strength of anchorage and efficiency of nutrition for the trees. We also demonstrate that the presence of plantations influences certain chemical properties of the desert soil, with differences depending on the tree species planted. In addition to presenting a method for planting trees in desert sites, this study underscores that a reliable evaluation of atmospheric carbon sequestration in trees must necessarily include root excavation to obtain an accurate measurement of biomass stored in belowground structures. Assessing the overall biomass produced by these trees allows us to determine the potential for carbon sequestration achievable through plantations established in desert sites.

Assessing the benefits and management of urban forest in supporting low carbon city in Jakarta, Indonesia

Abstract. Aulia R, Kaswanto, Arifin HS, Mosyaftiani A, Syasita N, Wahyu A, Wiyoga H. 2023. Assessing the benefits and management of urban forest in supporting low carbon city in Jakarta, Indonesia. Biodiversitas 24: 6151-6159. Climate change is a phenomenon that has become a global concern including in urban areas. Jakarta is one of the most populated cities in Indonesia, reaching 10.56 million people in 2020 with high emissions levels due to high human activities. Thus, efforts to reduce carbon emissions to mitigate climate change are necessary in Jakarta one of which is through the concept of low carbon city and manifested in the establishment of Green Open Space (GOS), including urban forests. Urban forests aim to sequester and store carbon, and improve the urban microclimate. This research aimed to assess the benefits of urban forests in Jakarta in term of their capacity in carbon sequestration using i-Tree Eco tool, and analyse the management of urban forests related to the applicable regulations. To collect data on trees, this study created 49 plots scattered across Srengseng Urban Forest, Cipayung Urban Forest, Munjul Urban Forest, Rawa Malang Urban Forest, and Pondok Labu Urban Forest. Tree species, Diameter at Breast Height (DBH), total tree height, live tree height, crown base height, crown width, percent crown loss, and crown light exposure were all gathered. Furthermore, in-depth interviews with urban forest managers were performed to gather additional information on present management, including questions derived from Jakarta's green open space legislation to assess management efficacy. The results of the analysis of urban forest quality show that the health status of trees is one of the factors that indicate the quality of urban forests at the five study sites, with more than 50% of the total trees in fair condition (75- 90% health). The gross carbon sequestration of trees in five urban forests Jakarta is about 184.8 metric tons of carbon per year. Additionally, the in-depth interviews also test the mortality of the urban forest, a decent indicator of current management with estimates over the next 10 years, showing a slight increase in carbon sequestration and storage capacity. However, the mortality scenario leads to a trend toward a decrease in leaf area and the number of tree categories, especially in the Srengseng Urban Forest.

Growth and carbon sequestration in biomass of Cordia alliodora in Andean agroforestry systems with coffee

Timber production and carbon sequestration in trees in agroforestry systems (AFS) are key to productivity and climate change mitigation. There are no studies about dynamics of growth and carbon sequestration of Cordia alliodora during all plantation cycle. The objective of this study was to develop models for diametric growth and carbon sequestration in aboveground biomass of C. alliodora in AFS with coffee in Líbano, Tolima, Colombia. Nonlinear models of growth and carbon sequestration in aboveground biomass of C. alliodora in AFS with coffee were developed. A total of 90 trees, ranging in age from 1 to 19 years, were randomly selected in farms and measured (diameter at breast height -dbh- and total height -h) in AFS with a basal area of C. alliodora between 0.22 and 17.8 m2/ha. Timber volume and aboveground biomass were estimated with allometric models, while carbon was estimated by multiplying aboveground biomass by 0.47. The best-fit models were selected according to the coefficient of determination (R2), Akaike's information criterion (AIC), predicted residual error sum of squares (PRESS), biological logic and a residual analysis. The highest growth rate of this species was reached at 4–6 years for dbh and h (3.6 cm/year and 2.9 m/year, respectively) and at 20 years for timber and carbon (0.60 m3/tree/year and 88.9 kg C/tree/year, respectively). In 20 years, a C. alliodora tree would store 1.1 Mg C and a AFS with 60 trees/ha would sequester between 260 Mg CO2/ha in aboveground biomass. The results show that C. alliodora trees could be maintained in the field for more than 20 years, thus increasing the volume per individual and carbon sequestration for a longer time. This demonstrates the importance of this species mainly when timber production and carbon sequestration are priorities for its profitability.

The Decline and Possible Return of Silvipastoral Agroforestry in Sweden

Silvipastoral agroforestry in the form of forest grazing and wooded semi-natural pastures has historically been very important for the Swedish supply of food and wood products for local use. Since the end of the 1800s, this form of combined production system has greatly decreased and now covers only 1% of Sweden’s land area. However, in recent decades it has gained increased relevance for reasons of landscape, biodiversity and climate. Agroforestry’s decline and possible future increase are described through reviews of statistics and the literature read by farmers and politicians whose decisions are behind the development. Especially when it comes to biodiversity and climate, this review also includes the scientific literature. Surveys on Swedish citizens’ valuation of silvipastoral agroforestry landscapes compared to treeless pasture and closed forest are also reviewed. It is possible that efforts to increase Sweden’s low self-sufficiency in beef and lamb meat, the coming requirements according to the EU’s nature restoration law and the need to limit climate change through carbon sequestration in trees may again increase the area of silvipastoral agroforestry. For this to be economically feasible, large grazing areas can be created out of remaining small scattered wooded semi-natural pastures and intervening forestland, which historically may have been grazed forests.

Comparative Assessment of Tree Carbon Sequestration Potential and Soil Carbon Dynamics of Major Plantation Crops and Homestead Agroforestry of Kerala, India

Designing sustainable food and agricultural systems is a pressing need at a time when we already are at the low end of achieving SDG 13 (Climate Action) of reducing carbon emissions. In such a scenario, this study has the potential to provide an insightful framework for policymakers. The major objective of this study is to estimate the carbon sequestration of tree crops, and soil analysis in homestead agroforestry systems (AFS), monocropped rubber plantations, and monocropped coconut plantations in the Alappuzha and Kollam districts of Kerala. The soil carbon parameters analyzed were soil organic carbon (SOC) and labile carbon. Other parameters, such as pH and electrical conductivity of soil, were also measured. The soil of rubber plantations had the least pH (4.8) and EC (79 µS/cm). We found the tree carbon sequestration of rubber trees in the plantations to be the highest (13.8 t C ha−1 year −1) followed by homestead AFS (2.68 t C ha−1 yr−1) and coconut tree plantation (2.08 ± 0.53 t C ha−1 year−1). The tree carbon sequestration potential was significantly (p = 0.003) influenced by the treatments. In soil, the SOC content was highest in the homestead AFS (2.48%). The labile carbon was also found to be higher in the homestead AFS (0.06%) but was least in rubber plantation (0.04%). These results indicate that even though the tree carbon sequestration of homestead AFS is lesser compared to that of large tree plantations such as rubber. The soil carbon pools and other physical and chemical properties of soil promote the valuable contribution that homestead can play in the sustainability of the environment and ensuring food security.

Afforestation of semi-arid regions of Mongolia: carbon sequestration in trees and increase of soil organic carbon

This work examines the variation of carbon sequestration (considered as the sum of above- and below-ground plant biomass production added to soil organic carbon) occurring in two sites (named respectively BN and ER) characterized by a semi-arid climate after planting three tree species (Populus sibirica, Ulmus pumila, and Hippophae rhamnoides). Soil organic carbon (SOC) was analyzed at four different depths (from 0–60 cm). In these two sites, the three tree species contributed differently to carbon sequestration. We found that above-ground plant biomass (leaf, branch, stem) was higher at the BN site whereas at the ER site prevailed below-ground biomass. That is probably due to the low tree density in BN site and the higher soil moisture content present in ER site. Among the three tree species considered, P. sibirica showed the highest biomass value. The SOC values were highest in the topsoil layer (0-40 cm) and decreased with depth. This works clearly shows that in semi-arid lands carbon sequestration depends on the environmental factors that characterize the site, the tree density, and the tree species selected.

Do Managed Hill Sal (Shorea robusta) Community Forests of Nepal Sequester and Conserve More Carbon than Unmanaged Ones?

Nepalese community forests are globally recognized for sustainable forest management and improving the livelihoods of forest-dependent communities, but their contribution to carbon sequestration in trees and soil is rarely studied. This study was performed to understand the effect of management practices on carbon stock of two community forests (CFs) - Taldanda (managed) and Dangdunge (unmanaged) - dominated by Sal (Shorea robusta) in the mid-hills of Nepal. Twenty-one concentric sample plots, each of 250 m2, were laid out in each forest to estimate different carbon pools and a stratified random sampling intensity of 0.5% used to collect data. Results showed significant (p<0.05) differences in above and below-ground biomass and carbon sequestration potential between the two CFs. The managed and unmanaged forests had total carbon stock of 269.3±27.4 and 150.0±22.7 ton/ha, respectively, demonstrating 1.79 times higher carbon stock in the former than the latter. The managed forest had significantly (p<0.05) greater mean soil organic carbon (SOC) stock than the unmanaged forest. The SOC was highest in the upper soil layer (0-10 cm), with a steady decrease as the soil depth increased. All other measured carbon pools values were higher in managed compared to unmanaged forest. The difference in carbon stock was due to the manipulation of different forest management activities, including thinning, timber extraction, fire control, grazing, and fuel wood/fodder extraction. The study suggests that the implementation of proper forest management would be necessary for enhancing carbon stock in forest trees and soils.

Carbon Sequestration Decision-Making Management Based on Model Construction

Nowadays, forests are integral to mitigating climate change. Fully exerting the carbon sequestration capacity of forests is related to whether the concentration in the atmosphere can be reduced and the trend of global warming can be restrained. Because forest composition, climate, population, interests, and values vary widely around the world, it is impractical to develop a model of forest management that applies to all regions, and the optimal management strategy for each forest is different. Modeling the carbon footprint of forest areas, from which the carbon sequestration of trees, understory vegetation and forest litter per unit area can be obtained, and trees can be further divided into young forests, middle-aged forests, and near-mature forests according to their age , mature forest and over-mature forest, comprehensively evaluate the established indicators through the entropy weight method, establish 3 first-level indicators and 6 second-level indicators, and combine the Pearson correlation coefficient to formulate the most relevant indicators. The maintenance of ecological balance is a forest management plan in Carbon dioxide sequestration in the Greater Khingan Range is the most efficient.

Biomass production and carbon stocks of poplar-based agroforestry with canola and wheat crops: a case study

Poplar (Populus deltoides Bartr. ex Marsh.) produce a large amount of biomass per unit area and is important fast-growing species in different planting systems. However, the appropriate space between poplar trees is essential to high-performance productivity in diverse regions. The present study monitored the effect of different spacing configurations (A: 4 × 3 m; B: 4 × 3 m (pure poplar); C: 6 × 3 m; D: 8 × 3 m; E: 10 × 3 m and F: pure crop) of poplar-based agroforestry with two canola (Brassica napus L.) and wheat (Triticum aestivum L.) cropping system on biomass production and carbon storage. Over the eight years, the total poplar biomass production was significantly different (P ≤ 0.05) in poplar-based configurations and ranged from 9.1 to 13.4 mg ha–1. The highest carbon storage of 6.5 mg ha–1 was observed in configuration E. Crop production of canola and wheat in configurations B, C, D, and E, did not show a significant difference with pure crop cultivation, while configuration A was significantly lower. Our result indicated that configuration E, with the highest total biomass production but no significant difference in crop production, is the optimum system of poplar-based agroforestry in regions with similar temperate climate conditions of Northern Iran. Finally, poplar-based agroforestry provides high efficiency of carbon sequestration in trees which can conserve all market and non-market benefits. Keywords: aboveground biomass, carbon concentration, crop yield, productivity, Populus deltoides, Northern Iran

Quantifying the CO2 Emissions of Motor Vehicles and the Urban Tree Carbon Sequestration Potential in the Lusaka Central Business District, Zambia

Quantifying the CO2 Emissions of Motor Vehicles and the Urban Tree Carbon Sequestration Potential in the Lusaka Central Business District, Zambia

Drought impacts on tree carbon sequestration and water use - evidence from intra-annual tree-ring characteristics.

Summary The impact of climate extremes on forest ecosystems is poorly understood but important for predicting carbon and water cycle feedbacks to climate. Some knowledge gaps still remain regarding how drought‐related adjustments in intra‐annual tree‐ring characteristics directly impact tree carbon and water use.In this study we quantified the impact of an extreme summer drought on the water‐use efficiency and carbon sequestration of four mature Norway spruce trees. We used detailed observations of wood formation (xylogenesis) and intra‐annual tree‐ring properties (quantitative wood anatomy and stable carbon isotopes) combined with physiological water‐stress monitoring.During 41 d of tree water deficit, we observed an enrichment in 13C but a reduction in cell enlargement and wall‐thickening processes, which impacted the anatomical characteristics. These adjustments diminished carbon sequestration by 67% despite an 11% increase in water‐use efficiency during drought. However, with the resumption of a positive hydric state in the stem, we observed a fast recovery of cell formation rates based on the accumulated assimilates produced during drought.Our findings enhance our understanding of carbon and water fluxes between the atmosphere and forest ecosystems, providing observational evidence on the tree intra‐annual carbon sequestration and water‐use efficiency dynamics to improve future generations of vegetation models.

Carbon storage and sequestration rates of trees inside and outside forests in Great Britain

Efforts to abate climate change heavily rely on carbon sequestration by trees. However, analyses of tree carbon dynamics often neglect trees outside of forests (TOFs) and spatially detailed information about tree carbon sequestration rates are largely missing. Here we describe a new method which combines remote sensing with forest inventory data from 127 358 sites to first estimate tree age and site productivity, which we then used to estimate carbon storage and sequestration rates for all trees inside and outside forests across Great Britain. Our models estimate carbon storage and sequestration rates with R 2 values of 0.86 and 0.56 (root-mean-square errors of 70 tCO2e ha−1 and 3.4 tCO2e ha−1 yr−1). They also reveal the important finding that 17% (165.6 MtCO2e) of the total carbon storage and 21% (3.4 MtCO2e yr−1) of the total carbon sequestration rate of all trees in Great Britain come from TOF, with particularly high contributions in England (24.3% and 34.1%), followed by Wales (12.5% and 17.6%) and Scotland (2.6% and 1.8%). Future estimates of carbon status and fluxes need to account for the significant contributions of TOF because these trees, often found in field margins and hedgerows are potentially an important carbon offset. Our novel approach enables carbon baseline assessments against which changes can be assessed at management relevant scales, improving the means to measure progress towards net zero emissions targets and associated environmental policies.

Understanding the economic barriers to the adoption of agroforestry: A Real Options analysis

Agroforestry has a potentially important role in helping agriculture address both the climate and biodiversity crises. It provides a means of producing additional marketable goods from agricultural land and enhancing biodiversity at the same time as increasing carbon sequestration and, in silvo-pastural systems, reducing carbon emissions if livestock stocking rates are reduced. However, the uptake of agroforestry in the UK has been limited. This paper adopts Real Options techniques to explore how the decision to adopt agroforestry is influenced by the relative levels of returns from agriculture, forestry and the price of carbon under the scenario where there are financial penalties from livestock Greenhouse Gas (GHG) emissions, financial benefits from carbon sequestration in trees and reversibility in land use decisions. The results are compared to the equivalent findings from a Land Equivalent Value capital budgeting approach to agroforestry adoption. Analysis is based on data from a case study upland livestock farm in Scotland, comparing the impacts of introducing agroforestry into the hill sheep enterprise or the low ground cattle and sheep enterprise. The results suggest that the adoption of agroforestry is far less likely than would be suggested by standard budgeting approaches, especially in more extensive upland enterprises (hill area) where sequestration benefits are low relative to more productive farmland areas (low ground area). Upfront support payments are shown to increase the likelihood of agroforestry adoption. They also have the effect of reducing the rotation length of forestry in such systems.

Assessment of Biomass Storage, Net Accumulation and Carbon Sequestration in Chir-Pine (<i>Pinus roxburghii</i> Sarg.) Dominated Community Forests of Kumaun Himalaya in relation to Climate Change

The present study deals with the vegetation analysis, biomass storage and carbon sequestration at three different aspects of Van Panchayat (Community) forest sites around Nainital district of Kumaun Himalayas. All three aspects, viz; south-east (SE), east (E) and south (S) of Van Panchayat forests are dominated by Pinus roxburghii Sarg. The density of trees across all aspects of community forests varied from 450 to 670 individuals ha -1 . The basal area values reported varied from 31.16 to 56.32 m 2 ha -1 . The species diversity across aspects ranged from 0.440 to 1.389, 1.656 to 2.319 and 1.962 to 3.152 for trees, shrubs and herbs, respectively. Total biomass storage values of trees across all aspects ranged from 155.83 to 333.77 t ha-1. Net biomass accumulation by trees was 10.53 t ha -1 yr -1 on SE aspect (Chir-Pine forest), 8.05 t ha -1 yr -1 on E aspect (Chir Pine forest) and 7.96 t ha -1 yr -1 on S aspect (Chir-Pine forest). Net annual carbon sequestration of trees varied between 3.54 and 4.36 t C ha -1 yr -1 . The density, biomass storage, net annual biomass accumulation as well as carbon sequestration values reported are higher on SE aspect. It can be predicted that South-East aspect (mixed aspect) plays a significant role in forest growth and maturity as compared to East and South (singal) aspects. In general, strong rules and regulations and effective enforcement must have minimized degradation and deforestation of forests in this Van Panchyat. This will certainly help in increasing forest cover and reducing carbon emission which will lead to minimise rise in CO 2 level of the atmosphere.

Tree restoration and ecosystem carbon storage in an acid and metal impacted landscape: Chronosequence and resampling approaches

Tree restoration on degraded land has been identified as an effective and affordable capture carbon strategy but it is unclear if carbon sequestration rates are comparable to rates on non-industrially impacted silvicultural forests. To this end, we resampled a jack pine (Pinus banksiana) and red pine (P. resinosa) chronosequence 16 years after the initial measurement to quantify carbon pools following ca. 40 years of regreening on an acid and metal impacted landscape. Measured carbon pools were then compared to those reported in an unpublished study to determine how carbon sequestration rates have changed over time and if repeated sampling at the stand level validates temporal trends estimated by the chronosequence. Total ecosystem carbon (TEC) within the stands ranged from 55 to 136 Mg ha−1 with a regional mean of 90.2 ± 9.6 Mg ha−1. On average, tree and soil organic pools (SOC) were the two largest carbon pools, representing 47% and 42% of TEC, respectively. Compared with unplanted sites, tree restoration resulted in a significant increase in the mean TEC among all sites of 54.4 ± 10.2 Mg ha−1 with a corresponding sequestration rate of 1.7 ± 0.3 Mg ha−1 yr−1. The chronosequence approach was only able to consistently detect a change in the tree carbon pool. In contrast, repeated sampling at the stand level identified changes in carbon sequestration rates within SOC, LFH and shrub carbon pools and showed that the chronosequence tree carbon sequestration rate was underestimated by a factor of 2.3. Chronosequence studies assume study sites have similar landscape history and environmental conditions, which may not be reasonable in highly degraded landscapes where past events (e.g., pollution, erosion, restoration) influence multiple landscape characteristics (e.g., local hydrology and topography). We conclude that tree restoration on impacted landscapes can sequester carbon at a rate comparable to silvicultural plantations in a similar climatic region and that reforestation of industrially damaged landscapes could be part of an effective carbon capture strategy.

Measurement of Sequestered Standing Carbon Stock in Major Agroforestry Tree Species

In the present investigation, the aboveground and belowground carbon sequestration potential of agroforestry tree species from seven sectors of Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU) campus was measured as a proxy of carbon fixation of agroforestry trees in Bangladesh. This campus occupies the area of 75.55 ha. Carbon emission has been increasing day by day due to anthropogenic activities and contributing to global climate change. Biomass production in different forms, i.e., aboveground biomass (AGB), belowground biomass (BGB), total biomass (TB), plays an essential role in carbon sequestration in trees. We estimated these biomasses by the nondestructive method to calculate the aboveground carbon (AGC), belowground carbon (BGC), total carbon (TC), and total CO2 of the study area. We found that the standing aboveground biomass and belowground biomass of agroforestry trees were 29.97 tha-1 and 7.79 tha-1 respectively, while the total standing biomass of agroforestry trees in 75.55 ha area was 37.76 tha-1. In the case of carbon, we observed that the total carbon sequestration and total carbon dioxide intake of agroforestry trees were 18.88 tha-1 and 69.29 tons CO2, respectively, in the study area. The highest carbon dioxide sequestration was observed in sector 6 (25%), and the lowest was observed in sector 3 (5%). The findings of carbon sequestration obtained from this study will be helpful for policymakers to take necessary steps against the adverse effect of global warming through carbon emission.