Root Carbon Sequestration and Its Efficacy in Forestry and Agroforestry Systems: A Case of Populus euramericana I-214 Cultivated in Mediterranean condition
Poplar is one of the most popular species of forestry and agroforestry land-use worldwide. It is currently assuming a growing importance for timber, bioenergy production and Carbon sequestration. Soil Carbon accumulation is associated with root litter, whereas available studies are disproportionate on root system in this species. Therefore, the study aimed at finding how much root Carbon, a hybrid poplar species (Populus euramericana I-214) sequestered in Forest System (FRS) and Agroforest System (AFS) by using soil excavation and root coring methods. A suitable conversion factor was used to get sequestered Carbon estimated from biomass. Carbon was distributed in maximum length, breadth and depth through different root components of both the systems, AFS occupied more rooting volume. Total belowground sequestered Carbon was higher in AFS (59.2 kg tree-1) than FRS (54.7 kg tree-1). The pattern was similar in other components like fine roots, medium roots, coarse roots and stump roots. However, on hectare basis, FRS accumulated (11.1 Mg ha-1) more Carbon than AFS (8.2 Mg ha-1). Although FRS stored higher belowground Carbon (without grain production), AFS was more efficient on account of Carbon land equivalent ratio. Thus the two available management systems have their own advantages in terms of Carbon storage and grain production.
Addo-Danso SD, Prescott CE, Smith AR (2016). Methods for estimating root biomass and production in forest and woodland ecosystem carbon studies: A review. Forest Ecology and Management 359:332-351.
Ajit, Das DK, Chaturvedi OP, Jabeen N, Dhyani SK (2011). Predictive models for dry weight estimation of above and below ground biomass components of Populus deltoides in India: Development and comparative diagnosis. Biomass and Bioenergy 35(3):1145-1152.
Albuquerque ERGM, Sampaio EVSB, Pareyn FGC, Araujo EL (2015). Root biomass under stem bases and at different distances from trees. Journal of Arid Environments 116:82-88.
Al Afas N, Marron N, Zavalloni C, Ceulemans R (2008). Growth and production of a short-rotation coppice culture of poplar-IV: Fine root characteristics of five poplar clones. Biomass and Bioenergy 32(6):494-502.
Allen SC, Jose S, Nair PKR, Brecke BJ, Nkedi-Kizza P, Ramsey CL (2004). Safety-net role of tree roots: evidence from pecan (Carya illinoiensis K. Koch) – cotton (Gossipium hirsutum L.) alley cropping system in the southern United States. Forest Ecology and Management 192:395-407.
Anderson HW, Papadopol CS, Zsuffa L (1983). Wood energy plantations in temperate climates. Forest Ecology Management 6:281-306.
Arora GS, Chaturvedi R, Kaushal A, Nain S, Tewari N, Alam M, Chaturvedi OP (2014). Growth, biomass, carbon stocks, and sequestration in an age series of Populus deltoides plantations in Tarai region of central Himalaya. Turkish Journal of Agriculture and Forestry 38:550-560.
Arraiolos A (2006). Etude d'un peuplier preleve sur une parcelle agroforestiere de Vezenobre dans l'objectif de caliber un model de culture agroforestiere. UMR-SYSTEM. Montpellier, Master thesis: 23p. Montpellier.
Banerjee H, Dhara PK, Mazumdar D (2009). Bamboo (Bambusa spp.) based agroforestry systems under rainfed upland ecosystem. Journal of Crop and Weed 5(1):286-290.
Berhongaray G, Verlinden MS, Broeckx LS, Ceulemans R (2015). Changes in belowground biomass after coppice in two Populus genotypes. Forest Ecology and Management 337:1-10.
Bishopp A, Help H, Helariutta Y (2009). Cytokinin signaling during root development. International Review of Cell and Molecular Biology 276:1-48.
Black KE, Harbron CG, Franklin M, Atkinson D, Hooker JE (1998). Differences in root longevity of some tree species. Tree Physiology 18:259-264.
Block RMA (2004). Fine root dynamics and carbon sequestration in juvenile hybrid poplar plantations in Saskatchewan, Canada. M.Sc. Thesis, Univ. of Saskatchewan, Saskatoon, SK.
Block RMA, Van Rees C.J, Knight JD (2006). A review of fine root dynamics in Populus plantations. Agroforestry Systems 67:73-84.
Brahim BM, Gavaland A, Cabanettes A (2000a). Generalized allometric regression to estimate biomass of Populus in short-rotation coppice. Scandinavian Journal of Forest Research 15:171-176.
Brahim BM, Gavaland A, Gauvin J (2000b). Growth and yield of mixed polyclonal stands of Populus in short-rotation coppice. Scandinavian Journal of Forest Research 15:605-610.
Bungart R, Huttl R (2004). Growth dynamics and biomass accumulation of 8-year-old hybrid poplar clones in a short-rotation plantation on a clayey-sandy mining substrate with respect to plant nutrition and water budget. European Journal of Forest Research 123:105-115.
Cairns MA, Brown S, Helmer EH, Baumgardner GA (1997). Root biomass allocation in the world’s upland forests. Oecologia (Berlin) 111:1-11.
Callesen I, Harrison R, Stupak I, Hatten J, Raulund-Rasmussen K, Boyle J, Clarke N, Zabowski D (2016). Carbon storage and nutrient mobilization from soil minerals by deep roots and rhizospheres. Forest Ecology and Management 359:322-331.
Chambers JQ, dos Santos J, Rebeiro RJ, Higuchi N (2001). Tree damage, allometric relationships, and aboveground net primary production in central Amazon forest. Forest Ecology and Management 152:73-84.
Chan YH (1982). Storage and release of organic carbon in peninsular Malaysia. International Journal of Environmental Studies 18:211-222.
Chaudhry AK (2003). Comparative study of different densities of poplar in wheat based agroforestry system in Central Punjab. Ph D Thesis. University of Agriculture, Faisalabad, Pakistan.
Chauhan SK, Gupta N, Walia R, Yadav S, Chauhan R, Mangat PS (2011). Biomass and carbon sequestration potential of Poplar-wheat intercropping system in irrigated agro-ecosystem in India. Journal of Agricultural Science and Technology A 1:575-586.
Chauhan SK, Brar MS, Sharma R (2012). Performance of poplar (Populus deltoides Bartr) and its effect on wheat yield under agroforestry system in irrigated agro-ecosystem, India. Caspian Journal of Environmental Sciences 10(1):53-60.
Chauhan SK, Sharma R, Singh B, Sharma SC (2015). Biomass production, carbon sequestration and economics of on-farm poplar plantations in Punjab, India. Journal of Applied and Natural Science 7(1):452-458.
Chen W, Zhang Q, Cihlar J, Bauhus J, Price DY (2004). Estimating fine-root biomass and production of boreal and cool temperate forests using aboveground measurements: A new approach. Plant and Soil 265:31-46.
Christersson L (2010). Wood production potential in poplar plantations in Sweden. Biomass and Bioenergy 34(9):1289-1299.
Coleman MD, Dickson RE, Isebrands JG (2000). Contrasting fine-root production, survival and soil CO2 efflux in pine and poplar plantations. Plant and Soil 225:129-139.
Cooper CF (1983). Carbon storage in managed forests. Canadian Journal of Forest Research 13:155-166.
Danial O, Vitorino ACT, Alovisi AA, Mazzochin L, Tokura AM, Pinheiro ER, De-Souza EF (1997). Phosphorus application to Acacia mangium Willd. seedlings. Revista Arvore 21:163-168.
Das DK, Chaturvedi OP (2005). Structure and function of Populus deltoides agroforestry systems in eastern India: I. Dry matter dynamics. Agroforestry System 65:215-221.
Dowell RC, Gibbins D, Rhoads JL, Pallardy SG (2009). Biomass production physiology and soil carbon dynamics in short-rotation-grown Populus deltoides and P. deltoides x P. nigra hybrids. Forest Ecology and Management 257:134-142.
Dougherty MC, Thevathasan NV, Gordon AM, Lee H, Kort J (2009). Nitrate and Escherichia coli NAR analysis in tile drain affluent from a mixed tree intercrop and monocrop system. Agriculture Ecosystem and Environment 131:77-84.
Douglas G, McIvor I, Potter JF, Foote L (2010). Root distribution of poplar at varying densities on pastoral hill country. Plant and Soil 333(1-2):147-161.
Fang S, Xu X, Lu S, Tang L (1999). Growth dynamics and biomass production in short-rotation poplar plantations: 6-year results for three clones at four spacings. Biomass and Bioenergy 17:415-425.
Fang S, Xue J, Tang L (2007). Biomass production and carbon sequestration potential in poplar plantations with different management patterns. Journal of Environmental Management 85:672-679.
Fang S, Xie B, Liu J (2008). Soil nutrient availability, poplar growth and biomass production on degraded agricultural soil under fresh grass mulch. Forest Ecology and Management 255:1802-1809.
FAO (2012). Improving lives with poplars and willows. Synthesis of country progress reports. 24th session of the International Poplar Commission, Dehradun, India. 30 Oct-2 Nov 2012. Working Paper IPC/12. Forest Assessment Management and Conservation Division FAO Rome.
Fierer N, Schimel JP, Holden PA (2003). Variations in microbial community composition through two soil depth profiles. Soil Biology and Biochemistry 35(1):167-176.
Fonseca W, Alice FE, Rey-Benayas JM (2011). Carbon accumulation in aboveground and belowground biomass and soil of different age native forest plantations in the humid tropical lowlands of Costa Rica. New Forest 43(2):197-211.
Fortier J, Gagnon D, Truax B, Lambert F (2010a). Biomass and volume yield after 6 years in multiclonal hybrid poplar riparian buffer strips. Biomass and Bioenergy 34:1028-1040.
Fortier J, Gagnon D, Truax B, Lambert F (2010b). Nutrient accumulation and carbon sequestration in 6-year-old hybrid poplars in multiclonal agricultural riparian buffer strips. Agriculture, Ecosystems and Environment 137(3-4):276-287.
Fortier J, Truax B, Gagnon D, Lambert F (2013). Root biomass and soil carbon distribution in hybrid poplar riparian buffers, herbaceous riparian buffers and natural riparian woodlots on farmland. SpringerPlus 2:539.
Fortier J, Truax B, Gagnon D, Lambert F (2015a). Biomass carbon, nitrogen and phosphorus stocks in hybrid poplar buffers, herbaceous buffers and natural woodlots in the riparian zone on agricultural land. Journal of Environmental Management 154: 333-345.
Fortier J, Truax B, Gagnon D, Lambert F (2015b). Plastic Allometry in Coarse Root Biomass of Mature Hybrid Poplar Plantations. BioEnergy Research 8(4):1691-1704.
Fukaki H, Tasaka M (2009). Hormone interactions during lateral root formation. Plant Molecular Biology 69(4):437-449.
Gao Y, Cheng J, Ma Z, Zhao Y, Su J (2014). Carbon storage in biomass, litter, and soil of different plantations in a semiarid temperate region of northwest China. Annals of Forest Science 71(4):427-435.
Gary GRA (2000). Root distribution of hybrid poplar in a temperate agroforestry intercropping system. Master Thesis. University of Guelph, Canada.
Gill RA, Jackson RB (2000). Global pattern of root turnover for terrestrial ecosystem. New Phytologist 147:13-31.
Gower ST, Krankina O, Olson RJ, Apps M, Linder S, Wang C (2001). Net primary production and carbon allocation patterns of boreal forest ecosystems. Ecological Applications 11:1395-1411.
Graefe S, Hertel D, Leuschner C (2008). Fine root dynamics along a 2,000-m elevation transect in South Ecuadorian mountain rainforests. Plant and Soil 313(1-2):155-166.
Guo D, Li H, Mitchell RJ, Han W, Hendricks JJ, Fahey TJ, Hendrick RL (2008). Fine root heterogeneity by branch order: exploring the discrepancy in root turnover estimates between minirhizotron and carbon isotopic methods. New Phytologist 177:443-56.
Guy RD, Benowicz A (1998). Can afforestation contribute to a reduction in Canada’s net CO2 emissions? Report prepared for Canadian Pulp and Paper Association. Mimeograph, March. Department of Forest Sciences, University of British Columbia, Vancouver, BC.
Hofmann-Schielle C, Jug A, Makeschin F, Rehfuess KE (1999). Short-rotation plantations of balsam poplars, aspen and willows on former arable land in the Federal Republic of Germany. I. Site–growth relationships. Forest Ecology and Management 121:41-55.
Hu YL, Zeng DH, Ma XQ, Chang SX (2016). Root rather than leaf litter input drives soil carbon sequestration after afforestation on a marginal cropland. Forest Ecology and Management 362:38-45.
Jha KK, Gupta C (1991). Intercropping of medicinal plants with poplar and their phenology. Indian Forester 117:335-544.
Jha KK, Srivastava PC, Varma RS, Prasad D (1991). Choice of spacing poplar in Tarai. Indian Journal of Forestry 14(3):163-168.
Jha KK (2009). The carbon balance of a poplar-cereal agroforestry system: A crossed modelling and measure approach. Masters Thesis, AgroParisTech-ENGREF, Montpellier, France.
Jha KK (2015). Carbon storage and sequestration rate assessment and allometric model development in young teak plantations of tropical moist deciduous forest, India. Journal of Forestry Research 26(3):589-604.
Jha KK (2017). Root structure and belowground biomass of hybrid poplar in forestry and agroforestry systems in Mediterranean France. Notulae Scientia Biologicae 9(3):422-432.
Johansson T, Karacic A (2011). Increment and biomass in hybrid poplar and some practical implications. Biomass and Bioenergy 35:1925-1934.
Johnsen KH, Wear JD, Oren R, Teskey RO, Sanchez F, Will R, Butnor J, Markewitz D, Richter D, Rials T, Allen HL, Seiler J, Ellsworth D, Maier C, Katul G, Dougherty PM (2001). Meeting global policy commitments: Carbon sequestration and southern pine forests. Journal of Forestry 99(4):14-21.
Kanime N, Kaushal R, Tewari SK, Raverkar KP, Chaturvedi S, Chaturvedi OP (2013). Biomass production and carbon sequestration in different tree-based systems of Central Himalayan Tarai region. Forest Trees and Livelihoods 22:38-50.
Kell DB (2012). Large-scale sequestration of atmospheric carbon via plant roots in natural and agricultural ecosystems: why and how. Philosphical Transaction of Royal Society B 367:1589-97.
Kern CC, Friend AL, Johnson JMF, Coleman MD (2004). Fine root dynamics in a developing Populus deltoides plantation. Tree Physiology 24:651-660.
Koerper G, Richardson C (1980). Biomass and net annual primary production regression for Populus grandidentata on three sites in northern lower Michigan. Canadian Journal of Forest Research 10:92-101.
Kort J, Turnock R (1998). Carbon reservoir and biomass in Canadian prairie shelterbelts. Agroforestry Systems 44(2-3):175-186.
Kutsokon NK, Jose S, Holzmueller E (2015). A Global Analysis of Temperature Effects on Populus Plantation Production Potential. American Journal of Plant Science 6(1):23-33.
Lackner KS (2003). A guide to CO2 sequestration. Science 300:1677-1678.
Laclau P (2003). Root biomass and carbon storage of ponderosa pine in a northwest Patagonia plantation. Forest Ecology and Management 173(1-3):353-360.
Levillain J, M’Bou AT, Deleporte P, Saint-Andre L, Jourdan C (2011). Is the simple auger coring method reliable for belowground standing biomass estimation in Eucalyptus forest plantation? Annals of Botany 108:221-230.
Liski J, Kaasalainen S, Raumonen P, Akujarvi A, Krooks A, Repo A, Kaasalainen M (2014). Indirect emissions of forest bioenergy: detailed modeling of stump root systems. GCB Bioenergy 6(6):777-784.
Lodhiyal LS, Lodhiyal N (1997a). Variation in biomass and net primary productivity in short rotation high density central Himalayan poplar plantations. Forest Ecology and Management 98(2-3):167-179.
Lodhiyal LS, Lodhiyal N (1997b). Aspects of productivity and nutrient cycling of Poplar (Populus deltoides Marsh) plantation in the moist plain area of the central Himalaya. Oecologia Montana 6(1-2):28-34.
Lodhiyal LS, Singh RP, Singh SP (1995). Structure and Function of an Age Series of Poplar Plantations in Central Himalaya: Dry Matter Dynamics. Annals of Botany 76:191-199.
Ludovici KH, Zarnoch SJ, Richter DD (2002). Modelling in pine root decomposition using data from a 60-year chronosequence. Canadian Journal of Forest Research 32:1675-1684.
Magnussen S, Reed D (2004). Modelling for estimation and monitoring. (FAO-IUFRO, 2004).
McCormack ML, Adams TS, Smithwick EAH, Eissenstat DM (2012). Predicting fine root lifespan from plant functional traits in temperate trees. New Phytologist 195:823-831.
McKenney DW, Yemshanov D, Fox G, Ramlal E (2004). Cost estimates for carbon sequestration from fast growing poplar plantations in Canada. Forest Policy and Economics 6:345-358.
Mead DJ, Willey RW (1980). The concept of “land equivalent ratio” and advantage in yields from intercropping. Experimental Agriculture 16:217-228.
Mulia R, Dupraz C (2006). Unusual fine root distributions of two deciduous tree species in southern France: What consequences for modelling of tree root dynamics? Plant and Soil 281(1-2):71-85.
Mulia R (2005). Modelisation tri-dimensionelle de la croissance du systeme racinaire des plantes en milieu heterogene avec l'approche de l'automate voxellaire. Universite de Montpellier II. Ph D Thesis: 86p.
Nielsen UB, Madsen P, Hansen JK, Nord-Larsen T, Nielsen AT (2014). Production potential of 36 poplar clones grown at medium length rotation in Denmark. Biomass and Bioenergy 64:99-109.
Nowak DJ, Crane DE (2002). Carbon storage and sequestration by urban trees in the USA. Environmental Pollution 116(3):381-389.
Oelbermann M, Voroney PR, Gordon AM (2004). Carbon sequestration in tropical and temperate agroforestry systems: a review with examples from Costa Rica and southern Canada. Agriculture Ecosystems and Environment 104:359-377.
Pallardy SG, Gibbins DE, Rhoads JL (2003). Biomass production by two-year-old poplar clones on floodplain sites in the Lower Midwest, USA. Agroforestry Systems 59(1):21-26.
Peichl M, Thevathasan N, Gordon A, Huss J, Abohassan R (2006). Carbon sequestration potentials in temperate tree-based intercropping systems, Southern Ontario, Canada. Agroforestry Systems 66:243-257.
Perry TO (1989). Tree roots: Facts and Fallacies. Arnoldia 49(4):3-29.
Pingale B, Bana OPS, Banga A, Chaturvedi S, Kaushal R, Tewari S, Neema (2014). Accounting biomass and carbon dynamics in Populus deltoides plantation under varying density in Tarai of central Himalaya. Journal of Tree Science 33(2):1-6.
Powlson DS, Smith P, Coleman K, Smith JU, Glendining M, Korschens M, Franko U (1998). A European network of long-term sites on soil organic matter. Soil and Tillage Research 47(3-4):263-274.
Pregitzer KS, Friend AL (1996). The structure and function of Populus root systems. In: Stettler RF (Ed.) Biology of Populus and its implications for management and conservation. NRC Research Press, Ottawa pp 331-354.
Puri S, Singh V, Bhushan B, Singh S (1994). Biomass production and distribution of roots in three stands of Populus deltoides. Forest Ecology and Management 65:135-147.
Raizada A, Jayaprakash J, Rathore AC, Tomar JMS (2013). Distribution of fine root biomass of fruit and forest tree species raised on old river bed lands in north western Himalaya. Tropical Ecology 54(2):251-261.
Reisner Y, de Filippi R, Herzog F, Palma J (2007). Target regions for silvoarable agroforestry in Europe. Ecological Engineering 29(4):401-418.
Rurak GA, Bockheim JG (1988). Biomass, net primary production and nutrient distribution for an age sequence of Populus tremuloides ecosystems. Canadian Journal of Forest Research 18(4):435-443.
Rytter R (1999). Fine root production and turnover in a willow plantation estimated by different calculation methods. Scandinavian Journal of Forest Research 14(6):526-537.
Rytter R (2012). The potential of willow and poplar plantations as carbon sinks in Sweden. Biomass and Bioenergy 36:86-95.
Schlesinger WH (1991). Biogeochemistry, an Analysis of Global Change. New York, USA: Academic Press.
Senga Y, Hiroki M, Terui S, Nohara S (2015). Variation in microbial function through soil depth profiles in the Kushiro Wetland, northeastern Hokkaido, Japan. Ecological Research 30:563-572.
Shelton M, Switzer G, Nelson L, Baker J, Mueller C (1982). The development of cottonwood plantations in alluvial soils. Mississippi State University Technical Bulletin 113:1-45.
Singh B, Sharma KN (2007). Tree growth and nutrient status of soil in a poplar (Populus deltoides Bartr.) based agroforestry system in Punjab, India. Agroforestry Systems 70:125-134.
Singh P, Lodhiyal LS (2009). Biomass and Carbon Allocation in 8-year-old Poplar (Populus deltoides Marsh) Plantation in Tarai Agroforestry Systems of Central Himalaya, India. New York Science Journal 2(6), ISSN 1554-0200.
Singh P, Singh B (2016). Biomass and nitrogen dynamics of fine roots of poplar under differential N and P levels in an agroforestry system in Punjab. Tropical Ecology 57(2):143-152.
Specht A, West PW (2003). Estimation of biomass and sequestered carbon on farm forest plantations in northern New South Wales, Australia. Biomass and Bioenergy 25:363-379.
Swamy SL, Mishra A, Puri S (2006). Comparison of growth, biomass and nutrient distribution in five promising clones of Populus deltoides under an agrisilviculture system. Bioresource Technology 97(1):57-68.
Teleniusa BF (1999). Stand growth of deciduous pioneer tree species on fertile agricultural land in southern Sweden. Biomass and Bioenergy 16:13-23.
Terakunpisut J, Gajaseni N, Ruankawe N (2007). Carbon sequestration potential in aboveground biomass of Thong Pha Phum national forest, Thailand. Applied Ecology and Environmental Research 5(2):93-102.
Tjoelker MG, Craine JM, Wedin D, Reich PB, Tilman D (2005). Linking leaf and root trait syndromes among 39 grassland and savannah species. New Phytologist 167:493-508.
Tufekcioglu A, Raich J, Isenhart T, Schultz R (1999). Fine root dynamics, coarse root biomass, root distribution, and soil respiration in a multispecies riparian buffer in central Iowa, USA. Agroforestry Systems 44:163-174.
Tufekcioglu A, Raich JW, Isenhart TM, Schultz RC (2003). Biomass, carbon and nitrogen dynamics of multi-species riparian buffers within an agricultural watershed in Iowa, USA. Agroforestry Systems 57(3):187-198.
Updegraff K, Baughman MJ, Taff SJ (2004). Environmental benefits of cropland conversion to hybrid poplar: economic and policy considerations. Biomass and Bioenergy 27:411-428.
Wang GG, Van Lear DH, Hu H, Kapeluck PR (2012). Accounting carbon storage in decaying root systems of harvested forests. Ambio 41:284-291.
Winans KS, Tardif AS, Lteif AE, Whalen JK (2015). Carbon sequestration potential and cost-benefit analysis of hybrid poplar, grain corn and hay cultivation in southern Quebec, Canada. Agroforestry Systems 89(3):421-433.
Wullschleger SD, Yin TM, DiFazio SP, Tschaplinski TJ, Gunter LE, Davis MF, Tuskan GA (2005). Phenotypic variation in growth and biomass for two advanced-generation pedigrees of hybrid poplar. Canadian Journal of Forest Research 35:1779-1789.
Yadava AK (2010). Biomass production and carbon sequestration in different agroforestry systems in Tarai region of Central Himalaya. Indian Forester 136(2):234-244.
Yocum WW (1937). Root development of young delicious apple trees as affected by soil and cultural treatment. University of Nebrasca Agriculture Experiment Station, Research Bulletin, 95:1-55.
Zabek L, Prescott C (2006). Biomass equations and carbon content of aboveground leafless biomass of hybrid poplar in Coastal British Columbia. Forest Ecology and Management 223(1-3):291-302.
Zan CS, Fyles JW, Girouard P, Samson RA (2001). Carbon sequestration in perennial bioenergy, annual corn and uncultivated systems in southern Quebec. Agriculture Ecosystem and Environment 86(2):135-144.
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