Index

ABSTRACT

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.

Keywords: Carbon sequestration, Agroforestry tree species, Biomass.

DOI: 10.20448/803.5.2.153.159

Citation | Ahmed, M.; Miah, M.M.U.; Abdullah, H. M.; Hossain, M.S.; Rubayet, M.T. (2020). Measurement of Sequestered Standing Carbon Stock in Major Agroforestry Tree Species. Canadian Journal of Agriculture and Crops, 5(2): 153-159.

Copyright: This work is licensed under a Creative Commons Attribution 3.0 License

Funding : The authors are very much pleased to Research Management Committee (RMC), BSMRAU for financial support (Grant No. 61/2007/641).

Competing Interests: The authors declare that they have no competing interests.

History : Received: 9 June 2020 / Revised: 13 July 2020 / Accepted: 17 August 2020 / Published: 3 September 2020.

Publisher: Online Science Publishing

1. INTRODUCTION

Carbon dioxide (CO2) emission has increased by 18% with an alarming rate in the environment by reaching to the highest level after 1750 [1]. In recent decades (2009-2010) CO2 level increased per year by 2.3ppb which was 1.5ppb in 1990-2000 and 2ppb in 2001-2009 [2]. Climate change as well as global warming were occurred as a results of CO2 emission, discussed in Kyoto protocol at Japan (1997)[3]. Kyoto protocol especially addressed the increasing carbon emissions around the world, which is now a major global issue [4, 5].

Greenhouse gas emissions can be reduced by controlling emissions primarily, and by storing carbon. Carbon sequestration in growing forests and other land use systems is known to be a cost-effective option for global warming and climatic change mitigation. Sequestration is the method of carbon dioxide reduction in the atmosphere with the aim of reducing world climate change. Trees i.e. biomass production play an important role in the reduction of CO2 from atmosphere by carbon sequestration. Active absorption of CO2 from the atmosphere by the photosynthetic process helps to store biomass in different plant parts and ultimately increases the carbon sequestration [4, 6]. Carbon stocks are composed of aboveground and belowground biomass with living and dead plants, and wood products, litter, and soil organic matter etc. are the major carbon pools in any ecosystem[7-9] .

In the sub-urban area of Gazipur District (Bangladesh), multiple industries releases CO2 in the atmosphere, which causes air pollution in the environment. In this district, Bangabandhu Sheikh MujiburRahman Agricultural University (BSMRAU) and Bhawal National Park act as a carbon pool with lot of agroforestry tree species. Agroforestry is a popular land management system in many countries, where forest resources are depleted. According to the state of world forest[10] Bangladesh is among the 15 countries, where both forest and agricultural land are decreasing. Agroforestry act as a tool for clean development mechanism to reverse land degradation and increase the carbon sequestration. Agroforestry species can be utilized as a source of wood and forest product demand, which can reduce the burden of natural forest. So, the improvement of urban green spaces with agroforestry trees is one of the possible ways to mitigate the adverse effects of urbanization in an ecological manner, making cities more beautiful and calm to live in [11]. Several ecosystem services are provided from trees including removal of atmospheric pollutants, biodiversity conservation, oxygen regeneration, reduction of noise pollution, microclimate regulation, mitigation of urban heat, prevention of soil erosion, groundwater recharge, and carbon sequestration [2]. Trees are important sinks for atmospheric carbon i.e. CO2 where 50% of tree standing biomass is carbon. Importance of green spaces for carbon sequestration is already accepted and well documented. But hardly any attempts have been made to study the potential of trees in carbon sequestration from sub-urban areas of Gazipur district. At the same time quantitative information on the agroforestry tree species is needed to know the contribution of agroforestry in carbon sequestration. So, this study intended to clarify the carbon sequestration by different agroforestry tree species in BSMRAU campus of Gazipur district.

2. MATERIALS AND METHODS

2.1. Study Area

The study conducted in Bangabandhu Sheikh MujiburRahman Agricultural University, Gazipur, Bangladesh. BSMRAU is located at the latitude 24o09” N and longitude 90o25” E. The average day temperature ranges from 86.9oF to 67.7oF. The study area is similar to the Bhawal National Park in term of soil properties and topography. The average annual rainfall in Gazipur city and adjoining area is 2036 mm [12]. The total 187 acres (75.55 ha) area of BSMRAU campus was selected for the carbon sequestration study which divided into seven sectors Figure 1. Representative tree species were selected for sampling from each sector of the study areaTable 1.

2.2. Biophysical Measurements

The height and diameter at breast height (DBH) are two important biophysical measurements for each tree sample. The height of the tree species was measured by Hypsometer instrument. The tree diameter at breast height (DBH) was measured by using diameter measure tape as well as alloy tree calipers.

2.3. Estimation of Aboveground Biomass (AGB)

All living biomass above the soil considered as aboveground biomass (AGB). The aboveground biomass (AGB) was calculated by multiplying the volume of biomass and wood density of tree species [13].
The calculated volume was based on diameter and height of trees, whereas the wood density value for the tree species obtained from web site (www.worldagroforestry.org).
Above ground biomass, AGB (g) = Volume of biomass (cm3) × Wood density (g/cm3)
Finally, the biomass of all tree species from all sectors (t) were calculated for total area (tha-1).

2.4. Estimation of Belowground Biomass (BGB)

The biomass of living roots excluding fine roots having <2mm diameter are considered as belowground biomass (BGB) [14]. The belowground biomass (BGB) was calculated by multiplying aboveground biomass taking 0.26 as the root to shoot ratio [13, 15].

Belowground biomass, BGB (tha-1) = 0.26 × Aboveground biomass, AGB (tha-1)
The carbon sequestration is multiplied by factor of 3.67 to get the carbon dioxide (CO2) because 1 ton carbon is equal to 3.67 tons of CO2 [16].

2.5. Data Analysis

The graphical presentation and calculations of data were implemented by the Excel software (version 2016) and the mapping of BSMRAU campus was created using ArcGIS 10 software (Environmental Systems Research Institute, Redlands, California, USA). GIS is widely used in land use land cover (LULC) monitoring in Bangladesh and elsewhere in the world [17, 18].

3. RESULTS AND DISCUSSION

The aboveground and belowground biomass in selected tree species were estimated by calculating carbon percentage and by measuring the tree height, DBH and wood density. The standing biomass stalks in agroforestry trees of seven sectors in BSMRAU campus were shown in Table 2. The highest aboveground, belowground and total biomass were observed in the trees species of sector 6 (7.49 tha-1, 1.95 tha-1 and 9.44 tha-1) followed by sector 7 (7.11 tha-1, 1.85 tha-1, 8.96 tha-1), sector 1 (4.76 tha-1, 1.24 tha-1, 6.00 tha-1), sector 5 (4.19 tha-1, 1.09 tha-1, 5.28 tha-1), sector 2 (2.80 tha-1, 0.73 tha-1, 3.53 tha-1), and sector 4 (2.14 tha-1, 0.56 tha-1, 2.70 tha-1). The lowest was observed in sector 3 (1.48 tha-1, 0.38 tha-1, 1.86 tha-1). In total, the aboveground and belowground biomass of agroforestry trees were 29.97 tha-1, 7.79 tha-1, respectively, while total biomass of agroforestry trees in 75.55 ha area was 37.76 tha-1. Generally, the carbon concentration of different tree parts assumed to be 50% of the dry weight [14, 19, 20] as the carbon content in any woody biomass of forest is around 50% of dry matter [14, 19, 21, 22] .

Note:AGB, Aboveground Biomass; BGB, Belowground Biomass; TB, Total Biomass; AGC, Aboveground Carbon; BGC, Belowground Carbon; TC, Total Carbon; tCO2, TonCO2.

The sequestered carbon stalks in agroforestry trees of BSMRAU campus are also given in Table 2. Similar to the biomass, the highest carbon content was sequestered as aboveground, belowground and total carbon in sector 6 (3.75 tha-1, 0.97 tha-1, 4.72 tha-1), followed by sector 7 (3.56 tha-1, 0.92 tha-1, 4.48 tha-1), sector 1 (2.38 tha-1, 0.62 tha-1, 3.00 tha-1), sector 5 (2.10 tha-1, 0.54 tha-1, 2.64 tha-1), sector 2 (1.40 tha-1, 0.36 tha-1, 1.76 tha-1), and sector 4 (1.07 tha-1, 0.28 tha-1, 1.35 tha-1). The lowest was found in sector 3 (0.74 tha-1, 0.19 tha-1, 0.93 tha-1).

The total sequestered carbon stalk in aboveground and belowground biomass of agroforestry tree species were 14.99 tha-1 and 3.90 tha-1 respectively, while total sequestered carbon of agroforestry trees in 75.55 hectares area was 18.88 tha-1. In BSMRAU campus, the total carbon dioxide intake by agroforestry trees was 69.29 tons CO2.

Figure 2 showed cumulative percentage of carbon dioxide intake (tCO2) in agroforestry trees in seven sectors of BSMRAU campus. The highest carbon dioxide sequestration was observed in sector 6 (25%) followed by sector 7 (24%), sector 1 (16%), sector 5 (14%), sector 2 (9%), sector 4 (7%) and lowest was observed in sector 3 (5%). The Gazipur district is densely populated area with a lot of commercial activities and developing as a prominent suburban area near Dhaka capital. In most places of Gazipur district, the natural vegetation is being replaced by the concrete industries and housing sectors. The vegetation of BSMRAU campus remain undisturbed in this situation for a long time which strongly helps in carbon sequestration. Moreover, growing more trees would be the only viable solution to maintain carbon sequestration balance in the study area.

4. CONCLUSION

The BSMRAU campus stored 37.76 tha-1 total standing biomass in different agroforestry tree species which cumulatively intake 69.29 tonsCO2 and helps in establishing a green campus with carbon sequestration, microclimatic modification etc. The highest carbon sequestration was observed in sector 6 and 7 due to wide range of agroforestry tree species coverage.

REFERENCES

[1]          B. Chavan and G. Rasal, "Total sequestered carbon stock of Mangifera indica," Journal of Environment and Earth Science, vol. 2, pp. 37-48, 2012.

[2]          S. Gharge and G. S. Menon, "Carbon stock sequestered by trees in Sadhu Vaswani Garden, Ulhasnagar," Journal of Environmental Science, Computer Science and Engineering & Technology, vol. 6, pp. 455-463, 2017.

[3]          UNTC (United Nations Treaty Collection), "Kyoto protocol to the United Nations framework convention on climate change. Retrieved from https:// https://treaties.un.org/pages/ViewDetails.aspx?src=TREATY&mtdsg_no=XXVII-7-a&chapter=27&lang=en. [Accessed 15 Jan 2020]," 2011.

[4]          B. Chavan and G. Rasal, "Sequestered standing carbon stock in selective tree species grown in University campus at Aurangabad, Maharashtra, India," International Journal of Engineering Science and Technology, vol. 2, pp. 3003-3007, 2010.

[5]          C. H. Wang, M. H. Ko, and W. J. Chen, "Effects of kyoto protocol on CO2 emissions: A five-country rolling regression analysis," Sustainability, vol. 11, pp. 2-20, 2019. Available at: http://doi:10.3390/su11030744 .

[6]          C. Jansson, S. D. Wullschleger, U. C. Kalluri, and G. A. Tuskan, "Phytosequestration: Carbon biosequestration by plants and the prospects of genetic engineering," Bioscience, vol. 60, pp. 685-696, 2010. Available at: https://doi.org/10.1525/bio.2010.60.9.6.

[7]          M. Saket, A. Branthomme, and M. Piazza, FAO NFMA – support to developing countries on national forest monitoring and assessment. Rome, Italy: Food and Agriculture Organization of the United Nations, 2005.

[8]          IPCC (Intergovernmental Panel on Climate Change), Good practice guidance or land use, land-use change and forestry. Hayama, Japan: Institute for Global Environmental Strategies (IGES), 2003.

[9]          IPCC (Intergovernmental Panel on Climate Change), Guidelines for national greenhouse gas inventories vol. 4. Hayama, Japan: Agriculture, Forestry and other land use (AFLOLU): Institute for Global Environmental Strategies, 2006.

[10]        FAO (Food and Agricultutre Organization), "State of the world’s forests 2016. Forests and agriculture: Land-use challenges and opportunities Rome, Italy," pp. 1-107, 2016.

[11]        K. De Ridder, V. Adamec, A. Bañuelos, M. Bruse, M. Bürger, O. Damsgaard, J. Dufek, J. Hirsch, F. Lefebre, and J. Pérez-Lacorzana, "An integrated methodology to assess the benefits of urban green space," Science of the Total Environment, vol. 334-335, pp. 489-497, 2004. Available at: https://doi.org/10.1016/j.scitotenv.2004.04.054.

[12]        A. Merkel, "Climate data.org. Retrieved from https://en.climate-data.org/asia/bangladesh/dhaka-division/gazipur-969817/#climategraph. [Accessed 12 Jan 2020]," 2012.

[13]        N. H. Ravindranath and M. Ostwald, "Carbon inventory methods handbook for greenhouse gas inventory," Carbon Mitigation and Round Wood Production Projects. Springer, vol. 29, pp. 1-304, 2008.

[14]        B. L. Chavan and G. B. Rasal, "Potentiality of carbon sequestration in six year ages young plant from university campus of Aurangabad," Global Journal of Researches in Engineering, vol. 11, pp. 15-20, 2011.

[15]        M. A. Cairns, S. Brown, E. H. Helmer, and G. A. Baumgardner, "Root biomass allocation in the world's upland forests," Oecologia, vol. 111, pp. 1-11, 1997. Available at: https://doi.org/10.1007/s004420050201.

[16]        S. Jasmin and V. Birundha, "Adaptation of climate change through forest carbon sequestration in Tamilnadu, India," International Journal of Research in Commerce & Management, vol. 1, pp. 36-40, 2011.

[17]        H. M. Abdullah, M. G. Mahboob, M. M. Rahman, and T. Ahmed, "Monitoring natural Sal forest cover in Modhupur, Bangladesh using temporal Landsat imagery during 1972–2015," International Journal of Environmental, vol. 5, pp. 1-7, 2015.

[18]        H. M. Abdullah, I. Islam, M. G. Miah, and Z. Ahmed, "Quantifying the spatiotemporal patterns of forest degradation in a fragmented, rapidly urbanizing landscape: A case study of Gazipur, Bangladesh," Remote Sensing Applications: Society and Environment, vol. 13, pp. 457-465, 2019. Available at: https://doi.org/10.1016/j.rsase.2019.01.002.

[19]        B. Chavan and G. Rasal, "Carbon sequestration potential of young Annona reticulate and Annona squamosa from University campus of Aurangabad," International Journal of Physical and Social Sciences, vol. 2, pp. 193-198, 2012.

[20]        B. K. Jana, S. Biswas, M. Majumder, P. K. Roy, and A. Mazumdar, "Comparative assessment of carbon sequestration rate and biomass carbon potential of young Shorea robusta and Albizzia lebbek," International Journal of Hydro-Climatic Engineering, vol. 1, pp. 1-15, 2009.

[21]        E. Paladinić, D. Vuletić, I. Martinić, H. Marjanović, K. Indir, M. Benko, and V. Novotny, "Forest biomass and sequestered carbon estimation according to main tree components on the forest stand scale," Periodicum Biologorum, vol. 111, pp. 459-466, 2009.

[22]        B. L. Chavan and G. B. Rasal, "Carbon sequestration potential of Mangifera indica in its various growth phases," presented at the 99th Indian Science Congress, Bhuvaneshwar, India, 2012.