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Research | Open Access

Natural forests in New Zealand - a large terrestrial carbon pool in a national state of equilibrium

Thomas Paul1 ( )Mark O. Kimberley2Peter N. Beets3
Scion, Private Bag 3020, Rotorua, 3046, New Zealand
Environmental Statistics Ltd, Whangapararoa, 0930, New Zealand
retired (previously Scion), Rotorua, 3010, New Zealand
Show Author Information

Abstract

Background

Natural forests cover approximately 29% of New Zealand's landmass and represent a large terrestrial carbon pool. In 2002 New Zealand implemented its first representative plot-based natural forest inventory to assess carbon stocks and stock changes in these mostly undisturbed old-growth forests. Although previous studies have provided estimates of biomass or carbon stocks, these were either not fully representative or lacked data from important pools such as dead wood (coarse woody debris). The current analysis provides the most complete estimates of carbon stocks and stock changes in natural forests in New Zealand.

Results

We present estimates of per hectare carbon stocks and stock changes in live and dead organic matter pools excluding soil carbon based on the first two measurement cycles of the New Zealand Natural Forest Inventory carried out from 2002 to 2014. These show that New Zealand's natural forests are in balance and are neither a carbon source nor a carbon sink. The average total carbon stock was 227.0 ± 14.4 tC·ha-1 (95% C.I.) and did not change significantly in the 7.7 years between measurements with the net annual change estimated to be 0.03 ± 0.18 tC·ha-1·yr-1. There was a wide variation in carbon stocks between forest groups. Regenerating forest had an averaged carbon stock of only 53.6 ± 9.4 tC·ha-1 but had a significant sequestration rate of 0.63 ± 0.25 tC·ha-1·yr-1, while tall forest had an average carbon stock of 252.4 ± 15.5 tC·ha-1, but its sequestration rate did not differ significantly from zero (-0.06 ± 0.20 tC·ha-1·yr-1). The forest alliance with the largest average carbon stock in above and below ground live and dead organic matter pools was silver beech-red beech-kamahi forest carrying 360.5 ± 34.6 tC·ha -1. Dead wood and litter comprised 27% of the total carbon stock.

Conclusions

New Zealand's Natural Forest Inventory provides estimates of carbon stocks including estimates for difficult to measure pools such as dead wood and roots. It also provides estimates of uncertainties including effects of model prediction error and sampling variation between plots. Importantly it shows that on a national level New Zealand's natural forests are in balance. Nevertheless, this is a nationally important carbon pool that requires continuous monitoring to identify potential negative or positive changes.

References

 
Allen RB (1993) A permanent plot method for monitoring changes in indigneous forests: a field manual. Manaaki Whenua, Chrischurch, p 24
 
Beaglehole H (2012) Fire in the hills: a history of rural fire-fighting in New Zealand. Cantebury University Press, Christchurch
 

Beets P, Kimberley M, Paul T, Oliver G, Pearce S, Buswell J (2014) The inventory of carbon stocks in New Zealand's Post-1989 natural Forest for reporting under the Kyoto protocol. Forests 5(9): 2230-2252. https://doi.org/10.3390/f5092230

 

Beets PN, Brandon AM, Goulding CJ, Kimberley MO, Paul TSH, Searles N (2011) The inventory of carbon stock in New Zealand's post-1989 planted forest for reporting under the Kyoto protocol. Forest Ecol Manag 262(6): 1119-1130. https://doi.org/10.1016/j.foreco.2011.06.012

 

Beets PN, Brandon AM, Goulding CJ, Kimberley MO, Paul TSH, Searles N (2012a) The national inventory of carbon stock in New Zealand's pre-1990 planted forest using a LiDAR incomplete-transect approach. Forest Ecol Manag 280: 187-197. https://doi.org/10.1016/j.foreco.2012.05.035

 
Beets PN, Kimberley MO, Goulding CJ, Garrett LG, Oliver GR, Paul TSH (2009) Natural forest plot data analysis: carbon stock analyses and re-measurement strategy. Scion, Rotorua
 

Beets PN, Kimberley MO, Oliver GR, Pearce SH, Graham JD, Brandon A (2012b) Allometric equations for estimating carbon stocks in natural forest in New Zealand. Forests 3(3): 818-839. https://doi.org/10.3390/f3030818

 

Birdsey R, Pregitzer K, Lucier A (2006) Forest carbon management in the United States: 1600-2100. J Environ Quality 35(4): 1461-1469. https://doi.org/10.2134/jeq2005.0162

 

Brando PM, Balch JK, Nepstad DC, Morton DC, Putz FE, Coe MT, Silvério D, Macedo MN, Davidson EA, Nóbrega CC, Alencar A, Soares-Filho BS (2014) Abrupt increases in Amazonian tree mortality due to drought-fire interactions. PNAS 111(17): 6347-6352. https://doi.org/10.1073/pnas.1305499111

 
Brienen RJW, Phillips OL, Feldpausch TR, Gloor E, Baker TR, Lloyd J, Lopez-Gonzalez G, Monteagudo-Mendoza A, Malhi Y, Lewis SL, Vásquez Martinez R, Alexiades M, Álvarez Dávila E, Alvarez-Loayza P, Andrade A, Aragaõ LEOC, Araujo-Murakami A, Arets EJMM, Arroyo L, Aymard CGA, Bánki OS, Baraloto C, Barroso J, Bonal D, Boot RGA, Camargo JLC, Castilho CV, Chama V, Chao KJ, Chave J, Comiskey JA, Cornejo Valverde F, Da Costa L, De Oliveira EA, Di Fiore A, Erwin TL, Fauset S, Forsthofer M, Galbraith DR, Grahame ES, Groot N, Hérault B, Higuchi N, Honorio Coronado EN, Keeling H, Killeen TJ, Laurance WF, Laurance S, Licona J, Magnussen WE, Marimon BS, Marimon-Junior BH, Mendoza C, Neill DA, Nogueira EM, Núñez P, Pallqui Camacho NC, Parada A, Pardo-Molina G, Peacock J, Penã-Claros M, Pickavance GC, Pitman NCA, Poorter L, Prieto A, Quesada CA, Ramírez F, Ramírez-Angulo H, Restrepo Z, Roopsind A, Rudas A, Salomaõ RP, Schwarz M, Silva N, Silva-Espejo JE, Silveira M, Stropp J, Talbot J, Ter Steege H, Teran-Aguilar J, Terborgh J, Thomas-Caesar R, Toledo M, Torello-Raventos M, Umetsu RK, Van Der Heijden GMF, Van Der Hout P, Guimarães Vieira IC, Vieira SA, Vilanova E, Vos VA, Zagt RJ (2015) Long-term decline of the Amazon carbon sink. Nature 519(7543): 344-348. https://doi.org/10.1038/nature14283
 

Brown JA, Robertson BL, McDonald T (2015) Spatially balanced sampling: application to environmental surveys. Procedia Environ Sci 27: 6-9. https://doi.org/10.1016/j.proenv.2015.07.108

 

Carey EV, Sala A, Keane R, Callaway RM (2001) Are old forests underestimated as global carbon sinks? Glob Change Biol 7(4): 339-344. https://doi.org/10.1046/j.1365-2486.2001.00418.x

 

Ciais P, Tan J, Wang X, Roedenbeck C, Chevallier F, Piao SL, Moriarty R, Broquet G, Le Quéré C, Canadell JG, Peng S, Poulter B, Liu Z, Tans P (2019) Five decades of northern land carbon uptake revealed by the interhemispheric CO2 gradient. Nature 568(7751): 221-225. https://doi.org/10.1038/s41586-019-1078-6

 

Clark DB, Clark DA (2000) Landscape-scale variation in forest structure and biomass in a tropical rain forest. Forest Ecol Manag 137(1-3): 185-198. https://doi.org/10.1016/S0378-1127(99)00327-8

 

Coomes DA, Allen RB, Scott NA, Goulding C, Beets P (2002) Designing systems to monitor carbon stocks in forests and shrublands. Forest Ecol Manag 164(1-3): 89-108. https://doi.org/10.1016/S0378-1127(01)00592-8

 
Davis MR, Wilde RH, Garrett LG, Oliver GR (2004) New Zealand carbon monitoring system: soil data collection manual. Caxton Press, Christchurch
 

Du E, de Vries W (2018) Nitrogen-induced new net primary production and carbon sequestration in global forests. Environ Pollut 242(Pt B): 1476-1487. https://doi.org/10.1016/j.envpol.2018.08.041

 

Easdale TA, Richardson SJ, Marden M, England JR, Gayoso-Aguilar J, Guerra-Cárcamo JE, McCarthy JK, Paul KI, Schwendenmann L, Brandon AM (2019) Root biomass allocation in southern temperate forests. Forest Ecol Manag 453: 117542. https://doi.org/10.1016/j.foreco.2019.117542

 

Fisher JI, Hurtt GC, Thomas RQ, Chambers JQ (2008) Clustered disturbances lead to bias in large-scale estimates based on forest sample plots. Ecol Lett 11(6): 554-563. https://doi.org/10.1111/j.1461-0248.2008.01169.x

 

Friedlingstein P, Jones MW, O'Sullivan M, Andrew RM, Hauck J, Peters GP, Peters W, Pongratz J, Sitch S, Le Quéré C, Bakker DCE, Canadell JG, Ciais P, Jackson RB, Anthoni P, Barbero L, Bastos A, Bastrikov V, Becker M, Bopp L, Buitenhuis E, Chandra N, Chevallier F, Chini LP, Currie KI, Feely RA, Gehlen M, Gilfillan D, Gkritzalis T, Goll DS, Gruber N, Gutekunst S, Harris I, Haverd V, Houghton RA, Hurtt G, Ilyina T, Jain AK, Joetzjer E, Kaplan JO, Kato E, Klein Goldewijk K, Korsbakken JI, Landschützer P, Lauvset SK, Lefèvre N, Lenton A, Lienert S, Lombardozzi D, Marland G, McGuire PC, Melton JR, Metzl N, Munro DR, Nabel JEMS, Nakaoka SI, Neill C, Omar AM, Ono T, Peregon A, Pierrot D, Poulter B, Rehder G, Resplandy L, Robertson E, Rödenbeck C, Séférian R, Schwinger J, Smith N, Tans PP, Tian H, Tilbrook B, Tubiello FN, van der Werf GR, Wiltshire AJ, Zaehle S (2019) Global carbon budget 2019. Earth Syst Sci Data 11(4): 1783-1838. https://doi.org/10.5194/essd-11-1783-2019

 

Garrett LG, Kimberley MO, Oliver GR, Parks M, Pearce SH, Beets PN, Paul TSH (2019) Decay rates of above-and below-ground coarse woody debris of common tree species in New Zealand's natural forest. Forest Ecol Manag 438: 96-102. https://doi.org/10.1016/j.foreco.2018.12.013

 

Goldstein A, Turner WR, Spawn SA, Anderson-Teixeira KJ, Cook-Patton S, Fargione J, Gibbs HK, Griscom B, Hewson JH, Howard JF, Ledezma JC, Page S, Koh LP, Rockström J, Sanderman J, Hole DG (2020) Protecting irrecoverable carbon in Earth's ecosystems. Nat Clim Chang 10(4): 287-295. https://doi.org/10.1038/s41558-020-0738-8

 

Gundersen P, Thybring EE, Nord-Larsen T, Vesterdal L, Nadelhoffer KJ, Johannsen VK (2021) Old-growth forest carbon sinks overestimated. Nature 591(7851): E21-E23. https://doi.org/10.1038/s41586-021-03266-z

 

Hall GMJ, Wiser SK, Allen RB, Beets PN, Goulding CJ (2001) Strategies to estimate national forest carbon stocks from inventory data: the 1990 New Zealand baseline. Glob Change Biol 7(4): 389-403. https://doi.org/10.1046/j.1365-2486.2001.00419.x

 

Hetzer J, Huth A, Wiegand T, Dobner HJ, Fischer R (2020) An analysis of forest biomass sampling strategies across scales. Biogeosciences 17(6): 1673-1683. https://doi.org/10.5194/bg-17-1673-2020

 

Holdaway RJ, Easdale TA, Carswell FE, Richardson SJ, Peltzer DA, Mason NWH, Brandon AM, Coomes DA (2017) Nationally representative plot network reveals contrasting drivers of net biomass change in secondary and old-growth forests. Ecosystems 20(5): 944-959. https://doi.org/10.1007/s10021-016-0084-x

 
Holdaway RJ, Easdale TA, Mason NWH, Carswell F (2014) LUCAS natural forest carbon analysis. Lincoln, Landcare Research
 

Houghton RA, Baccini A, Walker WS (2018) Where is the residual terrestrial carbon sink? Glob Change Biol 24(8): 3277-3279. https://doi.org/10.1111/gcb.14313

 
Intergovernmental Panel on Climate Change (IPCC) (2006) 2006 IPCC guidelines for national greenhouse gas inventories. Institute for Global Environmental Strategies, Hayama
 

Jarvis PG (1989) Atmospheric carbon dioxide and forests. Philos T Roy Soc B 324(1223): 369-392

 

Keith H, Lindenmayer D, MacKey B, Blair D, Carter L, McBurney L, Okada S, Konishi-Nagano T (2014) Managing temperate forests for carbon storage: impacts of logging versus forest protection on carbon stocks. Ecosphere 5(6): 1-34

 

Keith H, Mackey BG, Lindemayer DB (2009) Re-evaluation of forest biomass carbon stocks and lessons from the world's most carbon-dense forests. PNAS 106(28): 11635-11640. https://doi.org/10.1073/pnas.0901970106

 
Kimberley MO, Beets PN (2016) Methods of estimating height increments in the natural forest inventory. Contract report prepared for the Ministry for the Environment by Scion. Ministry for the Environment, Wellington
 

Kimberley MO, Beets PN, Paul TSH (2019) Comparison of measured and modelled change in coarse woody debris carbon stocks in New Zealand's natural forest. Forest Ecol Manag 434: 18-28. https://doi.org/10.1016/j.foreco.2018.11.048

 

Kurz W, Dymond C, Stenson G, Rampley G, Carroll A, Ebata T, Safranyik L (2008) Mountain pine beetle and forest carbon feedback to climate change. Nature 452(7190): 987-990. https://doi.org/10.1038/nature06777

 
Lal R, Lorenz K (2012) Carbon sequestration in temperate forests. In: Lal R, Lorenz K, Hüttl R, Schneider B, von Braun J (eds) Recarbonization of the biosphere. Springer, Dordrecht, pp 187-202. https://doi.org/10.1007/978-94-007-4159-1_9
 

Lewis SL, Lopez-Gonzalez G, Sonké B, Affum-Baffoe K, Baker TR, Ojo LO, Phillips OL, Reitsma JM, White L, Comiskey JA, Djuikouo KMN, Ewango CEN, Feldpausch TR, Hamilton AC, Gloor M, Hart T, Hladik A, Lloyd J, Lovett JC, Makana JR, Malhi Y, Mbago FM, Ndangalasi HJ, Peacock J, Peh KSH, Sheil D, Sunderland T, Swaine MD, Taplin J, Taylor D, Thomas SC, Votere R, Wöll H (2009) Increasing carbon storage in intact African tropical forests. Nature 457(7232): 1003-1006. https://doi.org/10.1038/nature07771

 

Lewis SL, Wheeler CE, Mitchard ETA, Koch A (2019) Restoring natural forests is the best way to remove atmospheric carbon. Nature 568(7750): 25-28. https://doi.org/10.1038/d41586-019-01026-8

 

Li W, Zhang P, Ye J, Li L, Baker PA (2011) Impact of two different types of El Niño events on the Amazon climate and ecosystem productivity. J Plant Ecol 4(1-2): 91-99. https://doi.org/10.1093/jpe/rtq039

 

Luyssaert S, Schulze ED, Börner A, Knohl A, Hessenmöller D, Law BE, Ciais P, Grace J (2008) Old-growth forests as global carbon sinks. Nature 455: 213

 

Malhi Y, Phillips OL, Baker TR, Phillips OL, Malhi Y, Almeida S, Arroyo L, Fiore AD, Erwin T, Higuchi N, Killeen TJ, Laurance SG, Laurance WF, Lewis SL, Monteagudo A, Neill DA, Vargas PN, Pitman NCA, Silva JNM, Martínez RV (2004) Increasing biomass in Amazonian forest plots. Philos T Roy Soc B 359(1443): 353-365

 

Mason N, Beets P, Payton I, Burrows L, Holdaway R, Carswell F (2014) Individual-based allometric equations accurately measure carbon storage and sequestration in shrublands. Forests 5(2): 309-324. https://doi.org/10.3390/f5020309

 

McGlone MS (1989) The Polynesian settlement of New Zealand in relation to environmental and biotic changes. New Zeal J Ecol 12: 115-129

 

McGuire AD, Zhu Z, Birdsey R, Pan Y, Schimel DS (2018) Introduction to the Alaska carbon cycle invited feature. Ecol Appl 28(8): 1938-1939. https://doi.org/10.1002/eap.1808

 

McKinley DC, Ryan MG, Birdsey RA, Giardina CP, Harmon ME, Heath LS, Houghton RA, Jackson RB, Morrison JF, Murray BC, Pataki DE, Skog KE (2011) A synthesis of current knowledge on forests and carbon storage in the United States. Ecol Appl 21(6): 1902-1924. https://doi.org/10.1890/10-0697.1

 

McMahon SM, Arellano G, Davies SJ (2019) The importance and challenges of detecting changes in forest mortality rates. Ecosphere 10(2): e02615. https://doi.org/10.1002/ecs2.2615

 
Ministry for the Environment (2012) Land use and carbon analysis system post-1989 natural forest data collection manual. Ministry for the Environment, Wellington
 
Ministry for the Environment (2018) Land use and carbon analysis system: natural forest data collection manual, version 2.8. Ministry for the Environment, Wellington
 
Ministry for the Environment (2020) LUCAS NZ land use map 1990 2008 2012 2016 v008. Ministry for the Environment, Wellington
 
New Zealand Government (1977) Reserves Act 1977. https://www.doc.govt.nz/about-us/our-role/legislation/reserves-act/. Accessed 15 May 2020
 

O'Sullivan M, Spracklen DV, Batterman SA, Arnold SR, Gloor M, Buermann W (2019) Have synergies between nitrogen deposition and atmospheric CO2 driven the recent enhancement of the terrestrial carbon sink? Global Biogeochem Cy 33(2): 163-180

 

Pan Y, Birdsey RA, Fang J, Houghton R, Kauppi PE, Kurz WA, Phillips OL, Shvidenko A, Lewis SL, Canadell JG, Ciais P, Jackson RB, Pacala SW, McGuire AD, Piao S, Rautiainen A, Sitch S, Hayes D (2011) A large and persistent carbon sink in the world's forests. Science 333(6045): 988-993. https://doi.org/10.1126/science.1201609

 

Paul TSH, Kimberley MO, Beets PN (2019) Thinking outside the square: evidence that plot shape and layout in forest inventories can bias estimates of stand metrics. Methods Ecol Evol 10(3): 381-388. https://doi.org/10.1111/2041-210X.13113

 
Payton IJ, Moore JR, Burrows LE, Goulding CJ, Beets PN, Dean M, Herries DL (2008) New Zealand carbon monitoring system planted forest data collection manual, version 3. The Caxton Press, Christchurch
 
Payton IJ, Newell CL, Beets PN (2004a) New Zealand carbon monitoring system: indigenous forest and shrubland data collection manual. Caxton Press, Christchurch, pp 1-68
 
Payton IJ, Newell CL, Beets PN (2004b) New Zealand carbon monitoring system: indigenous forest and shrubland data collection manual. Ministry for the Environment, Christchurch
 

Pugh TAM, Lindeskog M, Smith B, Poulter B, Arneth A, Haverd V, Calle L (2019) Role of forest regrowth in global carbon sink dynamics. PNAS 116(10): 4382-4387. https://doi.org/10.1073/pnas.1810512116

 

Rao JNK (1973) On double sampling for stratification and analytical surveys. Biometrika 60(1): 125-133. https://doi.org/10.1093/biomet/60.1.125

 

Schimel D, Stephens BB, Fisher JB (2015) Effect of increasing CO2 on the terrestrial carbon cycle. PNAS 112(2): 436-441. https://doi.org/10.1073/pnas.1407302112

 

Schlegel BC, Donoso PJ (2008) Effects of forest type and stand structure on coarse woody debris in old-growth rainforests in the Valdivian Andes, south-Central Chile. Forest Ecol Manag 255(5-6): 1906-1914. https://doi.org/10.1016/j.foreco.2007.12.013

 

Smithwick EAH, Harmon ME, Remillard SM, Acker SA, Franklin JF (2002) Potential upper bounds of carbon stores in forests of the pacific northwest. Ecol Appl 12(5): 1303-1317. https://doi.org/10.1890/1051-0761(2002)012[1303:PUBOCS]2.0.CO;2

 

Stephenson NL, Das AJ, Condit R, Russo SE, Baker PJ, Beckman NG, Coomes DA, Lines ER, Morris WK, Rüger N, Álvarez E, Blundo C, Bunyavejchewin S, Chuyong G, Davies SJ, Duque Á, Ewango CN, Flores O, Franklin JF, Grau HR, Hao Z, Harmon ME, Hubbell SP, Kenfack D, Lin Y, Makana JR, Malizia A, Malizia LR, Pabst RJ, Pongpattananurak N, Su SH, Sun IF, Tan S, Thomas D, van Mantgem PJ, Wang X, Wiser SK, Zavala MA (2014) Rate of tree carbon accumulation increases continuously with tree size. Nature 507(7490): 90-93. https://doi.org/10.1038/nature12914

 
Tomppo E, Gschwantner T, Lawrence D, McRoberts RE (2010) National forest inventories: pathways for common reporting. Springer, New York. https://doi.org/10.1007/978-90-481-3233-1
 
Tomppo E, Gschwantner T, Lawrence M, McRoberts RE (2009) National forest inventories. Business Media, Dordrechthttps://doi.org/10.1007/978-90-481-3233-1
 

Wagner F, Rutishauser E, Blanc L, Herault B (2010) Effects of plot size and census interval on descriptors of forest structure and dynamics. Biotropica 42(6): 664-671. https://doi.org/10.1111/j.1744-7429.2010.00644.x

 
Wiser S (2016) Vegetation classification of all measurements of the LUCAS natural forest plots. Contract report prepared for the Ministry for the Environment. Ministry for the Environment, Wellington
 

Wiser S, Bellingham PJ, Burrows L (2001) Managing biodiversity information: development of New Zealand's National Vegetation Survey databank. New Zeal J Ecol 25(2): 1-17

 

Wiser S, De Cáceres M (2013) Updating vegetation classifications: an example with New Zealand's woody vegetation. J Veg Sci 24(1): 80-93. https://doi.org/10.1111/j.1654-1103.2012.01450.x

 

Wiser SK, De Cáceress M (2018) New Zealand's plot-based classification of vegetation. Phytocoenologia 48(2): 153-161. https://doi.org/10.1127/phyto/2017/0180

 

Wiser SK, Hurst JM, Wright EF, Allen RB (2011) New Zealand's forest and shrubland communities: a quantitative classification based on a nationally representative plot network. Appl Veg Sci 14(4): 506-523. https://doi.org/10.1111/j.1654-109X.2011.01146.x

 

Xu CY, Turnbull MH, Tissue DT, Lewis JD, Carson R, Schuster WSF, Whitehead D, Walcroft AS, Li J, Griffin KL (2012) Age-related decline of stand biomass accumulation is primarily due to mortality and not to reduction in NPP associated with individual tree physiology, tree growth or stand structure in a Quercus-dominated forest. J Ecol 100(2): 428-440. https://doi.org/10.1111/j.1365-2745.2011.01933.x

Forest Ecosystems
Article number: 34
Cite this article:
Paul T, Kimberley MO, Beets PN. Natural forests in New Zealand - a large terrestrial carbon pool in a national state of equilibrium. Forest Ecosystems, 2021, 8(3): 34. https://doi.org/10.1186/s40663-021-00312-0

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Received: 04 May 2020
Accepted: 20 May 2021
Published: 02 June 2021
© The Author(s) 2021.

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