Estimation of soil carbon pools in the forests of Khyber Pakhtunkhwa Province, Pakistan

Abstract

Forest soils have high carbon densities compared to other land-uses. Soil carbon sequestration is important to reduce CO₂ concentrations in the atmosphere. An effective climate change mitigation strategy involves limiting the emissions of greenhouse gases from soils. Khyber Pakhtunkhwa is the most forested province of Pakistan, hosting about one-third of the country’s 4.5 × 10⁶ ha forest area. Soil organic carbon in the province’s forests was estimated through a field-based study carried out during 2014–17 covering the whole province. Data was collected from 373 sample plots laid out in different forest types using a stratified cluster sampling technique. The total quantity of soil organic carbon was estimated at 59.4 × 10⁶ t with an average of 52.4 ± 5.3 t/ha. About 69% of the total soil carbon is present in temperate forests. Subtropical broad-leaved and subtropical pine forests constitute 11.4% and 8.8% of the soil carbon stock respectively. Similarly, subalpine and oak forests have respective shares of 5.1% and 5.7% in the soil carbon pool. The lowest carbon stock (0.1%) was found in dry-tropical thorn forests. The highest soil carbon density was found in subalpine forests (69.5 ± 7.2 t/ha) followed by moist temperate forests (68.5 ± 6.7 t/ha) and dry temperate forests (60.7 ± 6.5 t/ha). Oak forests have carbon density of 43.4 ± 7.1 t/ha. Subtropical pine, subtropical broad-leaved and dry tropical thorn forests have soil carbon densities of 36.3 ± 3.7, 32.8 ± 6.2 and 31.5 ± 3.5 t/ha, respectively. The forests of the Khyber Pakhtunkhwa province have substantial amounts of soil carbon which must be conserved for climate change mitigation and maintenance of sound forest health.

Keywords

Soil carbon / Carbon sequestration / Climate change / Carbon sink / Forests / Khyber Pakhtunkhwa

References

[1] Agus F, Hairiah K, Mulyani A (2011) Measuring carbon stock in peat soils: practical guidelines. World Agroforestry Centre (ICRAF) Southeast Asia Regional Program, Indonesian Centre for Agricultural Land Resources Research and Development, Bogor, Indonesia, p 60

[2] Ali A. Forest cover mapping of Khyber Pakhtunkhwa, 2017, Peshawae: Pakistan Forest Institute 40

[3] Ali A (2019) Assessment of carbon stock and sequestration potential in forests of Khyber Pakhtunkhwa. (Ph.D. dissertation). Forestry and Range Management Department, PMAS Arid Agriculture, University, Rawalpindi, p 169

[4] Ali MK, Ahmad W, Malhi SS, Atta BM, Ghafoor A, Zia MH. Potential of carbon dioxide bio-sequestration of saline–sodic soils during amelioration under rice–wheat land use. Commun Soil Sci Plant Anal, 2013, 44: 2625-2635.

[5] Assefa G, Mengiistu T, Getu Z, Zewdiie S. Training Manual on Forest Carbon Pools and Carbon Stock Assessment in the Context of SFM and REDD+, 2013, Wondo Genet: College of Forestry and Natural Resources, Hawassa University 74

[6] Bukhari S, Haider A, Laeeq MT. Landcover atlas of Pakistan, 2012, Peshawar: Pakistan Forest Institute 140

[7] Chabhra A, Parlia S, Dadhwal VK. Soil organic carbon pools in Indian Forests. For Ecol Manag, 2003, 173(1): 187-199.

[8] Chisanga K, Bhardwaj DR, Pala NA, Thakur CL. Biomass production and carbon stock inventory of high-altitude dry temperate land use systems in North Western Himalaya. Ecol Process, 2018, 7: 22.

[9] EPA [Environmental Protection Agency]. Environmnetal profile of Khyber Pakhtunkhwa, 2017, Peshawar: Government of Khyber Pakhtunkhwa 570

[10] FAO [Food and Agricultural Organization] (2015) Forest Resource Assessment, Working Paper No. 180. Food and Agriculture Organization of the United Nations, Rome, Italy. http://www.fao.org/3/ap862e/ap862e00.pdf

[11] FAO [Food and Agricultural Organization] (2017) Soil organic carbon: the hidden potential. Food and Agriculture Organization of the United Nations, Rome, p 90

[12] Hartley J, Marchant J (1995). Methods of determining the moisture content of wood, Technical Paper No. 41. Research Division, State Forests of New South Wales, Sydney, p 61

[13] Hudson JM, Ghereni SA, Goldstein RA. Modelling the global carbon cycle: nitrogen fertilization of the terrestrial biosphere and the missing CO₂ sink. Glob Biogeochem Cycles, 1994, 8: 307-333.

[14] IPCC [Intergovernmental Panel on Climate Change] (2003) Good practice guidance for land use, land-use change and forestry. Intergovernmental Panel on Climate Change, p 590

[15] Khan I. Comparative fertility evaluation of agricultural forest and rangeland soils at Hilkot Watershed, Battal, district Mansehra, 2000, Peshawar: Department of Soil Science, NWFP Agriculture University 1 15

[16] Khattak R, Hussain Z. Evaluation of soil fertility status and nutrition of orchards. Soil Environ, 2007, 26(1): 22-32.

[17] Lal R. Soil management and restoration for carbon sequestration to mitigate the accelerated greenhouse effect. Prog Environ Sci, 1999, 4(1): 307-326.

[18] Liu Y, Li S, Sun X, Yu X. Variations of forest soil organic carbon and its influencing factors in east China. Ann For Sci, 2016, 73(2): 501-511.

[19] Maren I, Karki S, Prajapati S, Yadav R, Shresta B. Facing north or south: does slope aspect impact forest stand characteristics and soil properties in a semiarid trans-Himalayan valley?. J Arid Environ, 2015, 121: 112-123.

[20] Morisada K, Ono K, Kanomata H. Organic carbon stocks in forest soils in Japan. Geoderma, 2004, 119: 21-32.

[21] Nafees M, Jan MR, Khan H, Ali A. Status of soil texture and required associated soil conservation measure of river swat catchments area, NWFP, Pakistan. Sarhad J Agric, 2008, 24(2): 251-259.

[22] Nelson DW, Sommers LE. Sparks DL. Total carbon, organic carbon, and organic matter. Methods of soil analysis, part III, chemical methods, 1996, Madison: American Society of Agronomy Inc. 961 1010

[23] Nizami S (2010) Estimation of carbon stocks in subtropical managed and unmanaged forests of Pakistan. Ph.D. dissertation. PMAS Arid Agriculture University Rawalpindi, Rawalpindi, p 150

[24] Rehman M, Holmes A, Deurer M. Comparison of three methods to estimate organic carbon in allophanic soils in New Zealand, 2011, Tauranga: Horticulture Innovation Centre 1 4

[25] Saeed S, Ashraf MI, Ahmad A, Rahman Z. The Bela forest ecosystem of District Jhelum, a potential carbon sink. Pak J Bot, 2016, 48(1): 121-129.

[26] Sarfaraz H, Khan AA, Javed N, Ahmad S, Rahim I, Rafique M (2016) Khyber Pakhtunkhwa Biodiversity Strategy and Action Plan. Islamabad: Conservation and Sustainable Management of Biodiversity in Khyber Pakhtunkhwa, Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH, p 165

[27] Schumacher B (2002) Methods for the determination of total organic carbon (TOC) in soils and sediments. United States Environmental Protection Agency, Environmental Sciences Division National Exposure Research Laboratory, Las Vegas, p 25

[28] Shah S, Iqbal S, Ahmad A, Khan A. Soil organic carbon stock estimation in range lands of Kumrat Dir Kohistan KPK, Pakistan. J Ecol Nat Environ, 2015, 7(11): 277-288.

[29] Sheikh M. Trees of Pakistan, 1993, Peshawar: Pakistan Forest Institute 151

[30] Sheikh MA, Kumar M, Bussmann RW. Altitudinal variation in soil organic carbon stock in coniferous subtropical and broadleaf temperate forests in Garhwal Himalaya. Carbon Balance Manag, 2009, 4(6): 1-6.

[31] Shrestha BP, Devkota BP. Carbon stocks in the Oak and Pine Forests in Salyan District, Nepal. Banko Janakari, 2004, 23(2): 30-36.

[32] Siddiqui MF, Shaukat SS, Ahmed M, Siddiqui A. Influence of soil chemical properties, altitude and slope on the distribution and growth of coniferous species in moist temperate areas of Himalayan and Hindukush region of Pakistan. J Apol Environ Biol Sci, 2014, 4(9s): 130-140.

[33] Subedi B, Pandey S, Pandey A, Rana E, Bhattarai S, Banskota T. Forest carbon stock measurement: guidelines for measuring carbon stocks in community-managed forests, 2010, Kathmandu: International Centre for Integrated Mountain Development 79