Quantifying the Organic Carbon Held in Forested Soils of the United States and Puerto Rico *

Johnson, Mark G.; Kern, J.

doi:10.1201/9781420032277-4

Cited by 8 publications

(5 citation statements)

References 1 publication

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“…In the tropics, forests on drained peatland have been found to be about 25% more productive than upland forests in a similar climate (Hirano et al , 2007). While not all coastal plain soils are rich in organic matter, many of them have C densities up to an order of magnitude higher than upland soils (Johnson & Kern, 2003). And even on sandy soils, intensively managed commercial forests show net productivity up to four times higher than naturally regenerated stands (Powell et al , 2008).…”

Section: Introductionmentioning

confidence: 99%

Response of carbon fluxes to drought in a coastal plain loblolly pine forest

Noormets

Gavazzi

McNulty

et al. 2009

Global Change Biology

137

104

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Full accounting of ecosystem carbon (C) pools and fluxes in coastal plain ecosystems remains less studied compared with upland systems, even though the C stocks in these systems may be up to an order of magnitude higher, making them a potentially important component in regional C cycle. Here, we report C pools and CO 2 exchange rates during three hydrologically contrasting years (i.e. 2005-2007) in a coastal plain loblolly pine plantation in North Carolina, USA. The daily temperatures were similar among the study years and to the long-term average, whereas the amount and timing of precipitation differed significantly. Precipitation was the largest in 2005 (147 mm above normal), intermediate in 2006 (48 mm below) and lowest in 2007 (486 mm below normal). The forest was a strong C sink during all years, sequestering 361 AE 67 (2005), 835 AE 55 (2006) and 724 AE 55 (2007) g C m À2 yr À1 according to eddy covariance measurements of net ecosystem CO 2 exchange (NEE). The interannual differences in NEE were traced to drought-induced declines in canopy and whole tree hydraulic conductances, which declined with growing precipitation deficit and decreasing soil volumetric water content (VWC). In contrast, the interannual differences were small in gross ecosystem productivity (GEP) and ecosystem respiration (ER), both seemingly insensitive to drought. However, the drought sensitivity of GEP was masked by higher leaf area index and higher photosynthetically active radiation during the dry year. Normalizing GEP by these factors enhanced interannual differences, but there were no signs of suppressed GEP at low VWC during any given year. Although ER was very consistent across the 3 years, and not suppressed by low VWC, the total respiratory cost as a fraction of net primary production increased with annual precipitation and the contribution of heterotrophic respiration (R h ) was significantly higher during the wettest year, exceeding new litter inputs by 58%. Although the difference was smaller during the other 2 years (R h : litterfall ratio was 1.05 in 2006 and 1.10 in 2007), the soils lost about 109 g C m À2 yr À1 , outlining their potential vulnerability to decomposition, and pointing to potential management considerations to protect existing soil C stocks.

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Section: Introductionmentioning

confidence: 99%

Response of carbon fluxes to drought in a coastal plain loblolly pine forest

Noormets

Gavazzi

McNulty

et al. 2009

Global Change Biology

137

104

View full text Add to dashboard Cite

show abstract

“…This is not surprising because effects of afforestation and deforestation in the model are represented as proportions of the average regional soil carbon density value for each forest type, so variation in this parameter directly affects the predicted mass of carbon gain or loss. The soil carbon density values currently used in our model are based on published estimates derived by Johnson and Kern (2003) from the STATSGO soils database. More recent analyses of this database for the states of Maine and Minnesota by Amichev and Galbraith (2004) derive values of forest soil carbon density that are considerably lower than those of Johnson and Kern (2003).…”

Section: Model Sensitivity and Key Assumptionsmentioning

confidence: 99%

“…The soil carbon density values currently used in our model are based on published estimates derived by Johnson and Kern (2003) from the STATSGO soils database. More recent analyses of this database for the states of Maine and Minnesota by Amichev and Galbraith (2004) derive values of forest soil carbon density that are considerably lower than those of Johnson and Kern (2003). The authors attribute these differences to the assumption of a log-normal distribution of soil carbon density values within each forest type and to improved estimates of the volume of rock fragments.…”

Section: Model Sensitivity and Key Assumptionsmentioning

confidence: 99%

Land Use Change Effects on Forest Carbon Cycling Throughout the Southern United States

2006

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We modeled the effects of afforestation and deforestation on carbon cycling in forest floor and soil from 1900 to 2050 throughout 13 states in the southern United States. The model uses historical data on gross (two-way) transitions between forest, pasture, plowed agriculture, and urban lands along with equations describing changes in carbon over many decades for each type of land use change. Use of gross rather than net land use transition data is important because afforestation causes a gradual gain in carbon stocks for many decades, while deforestation causes a much more rapid loss in carbon stocks. In the South-Central region (Texas to Kentucky) land use changes caused a net emission of carbon before the 1980s, followed by a net sequestration of carbon subsequently. In the Southeast region (Florida to Virginia), there was net emission of carbon until the 1940s, again followed by net sequestration of carbon. These results could improve greenhouse gas inventories produced to meet reporting requirements under the United Nations Framework Convention on Climate Change. Specifically, from 1990 to 2004 for the entire 13-state study area, afforestation caused sequestration of 88 Tg C, and deforestation caused emission of 49 Tg C. However, the net effect of land use change on carbon stocks in soil and forest floor from 1990 to 2004 was about sixfold smaller than the net change in carbon stocks in trees on all forestland. Thus land use change effects and forest carbon cycling during this period are dominated by changes in tree carbon stocks.

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“…Stocks for the GIS approach are approximately 20 percent larger than stocks derived from the regression approach. The regression approach may underestimate the SOC density and stocks relative to the GIS method due to the fact that the regression-derived SOC density is applied to a multi-state region in which Wisconsin has some of the largest SOC concentrations (Johnson and Kern, 2003). Figure A5.…”

Section: Comparison Of Gis and Regression Resultsmentioning

confidence: 99%

“…The stock estimates are then adjusted based on assumptions of rates of change in stocks due to changes in land cover. The GIS-based SOC estimates have been the preferred methodology for recent studies (Amichev B. Y. and Galbraith, 2003, Heath et al, 2003b, Johnson and Kern, 2003, Ney et al, 2002.…”

Section: Regionmentioning

confidence: 99%

Optimal recovery of regional CO2 surface fluxes by data assimilation of anthropogenic and biogenic tracers

Campbell¹

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Quantifying the Organic Carbon Held in Forested Soils of the United States and Puerto Rico *

Cited by 8 publications

References 1 publication

Response of carbon fluxes to drought in a coastal plain loblolly pine forest

Response of carbon fluxes to drought in a coastal plain loblolly pine forest

Land Use Change Effects on Forest Carbon Cycling Throughout the Southern United States

Optimal recovery of regional CO2 surface fluxes by data assimilation of anthropogenic and biogenic tracers

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