Reforestation can sequester two petagrams of carbon in US topsoils in a century

Soils are Earth’s largest terrestrial carbon (C) pool, and their responsiveness to land use and management make them appealing targets for strategies to enhance C sequestration. Numerous studies have identified practices that increase soil C, but their inferences are often based on limited data extrapolated over large areas. Here, we combine 15,000 observations from two national-level databases with remote sensing information to address the impacts of reforestation on the sequestration of C in topsoils (uppermost mineral soil horizons). We quantify C stocks in cultivated, reforesting, and natural forest topsoils; rates of C accumulation in reforesting topsoils; and their contribution to the US forest C sink. Our results indicate that reforestation increases topsoil C storage, and that reforesting lands, currently occupying >500,000 km2 in the United States, will sequester a cumulative 1.3–2.1 Pg C within a century (13–21 Tg C·y−1). Annually, these C gains constitute 10% of the US forest sector C sink and offset 1% of all US greenhouse gas emissions.

Download Full-text

Continuous and discontinuous variation in ecosystem carbon stocks with elevation across a treeline ecotone

Biogeosciences ◽

10.5194/bg-12-1615-2015 ◽

2015 ◽

Vol 12 (5) ◽

pp. 1615-1627 ◽

Cited By ~ 10

Author(s):

J. D. M. Speed ◽

V. Martinsen ◽

A. J. Hester ◽

Ø. Holand ◽

J. Mulder ◽

...

Keyword(s):

Large Scale ◽

Mineral Soil ◽

Livestock Grazing ◽

Treeline Ecotone ◽

Soil C ◽

C Storage ◽

C Stocks ◽

C Stock ◽

The Impact ◽

Forest Line

Abstract. Treelines differentiate vastly contrasting ecosystems: open tundra from closed forest. Treeline advance has implications for the climate system due to the impact of the transition from tundra to forest ecosystem on carbon (C) storage and albedo. Treeline advance has been seen to increase above-ground C stocks as low vegetation is replaced with trees but decrease organic soil C stocks as old carbon is decomposed. However, studies comparing across the treeline typically do not account for elevational variation within the ecotone. Here we sample ecosystem C stocks along an elevational gradient (970 to 1300 m), incorporating a large-scale and long-term livestock grazing experiment, in the southern Norwegian mountains. We investigate whether there are continuous or discontinuous changes in C storage across the treeline ecotone, and whether these are modulated by grazing. We find that vegetation C stock decreases with elevation, with a clear breakpoint between the forest line and treeline above which the vegetation C stock is constant. C stocks in organic surface horizons of the soil were higher above the treeline than in the forest, whereas C stocks in mineral soil horizons are unrelated to elevation. Total ecosystem C stocks also showed a discontinuous elevational pattern, increasing with elevation above the treeline (8 g m−2 per metre increase in elevation), but decreasing with elevation below the forest line (−15 g m−2 per metre increase in elevation), such that ecosystem C storage reaches a minimum between the forest line and treeline. We did not find any effect of short-term (12 years) grazing on the elevational patterns. Our findings demonstrate that patterns of C storage across the treeline are complex, and should be taken account of when estimating ecosystem C storage with shifting treelines.

Download Full-text

Changes in carbon storage of broadcast burn plantations over 20 years

Canadian Journal of Soil Science ◽

10.4141/s06-012 ◽

2007 ◽

Vol 87 (1) ◽

pp. 93-102 ◽

Cited By ~ 6

Author(s):

J M Kranabetter ◽

A M Macadam

Keyword(s):

Lodgepole Pine ◽

Woody Debris ◽

Mineral Soil ◽

Biomass Accumulation ◽

Prescribed Burn ◽

Soil C ◽

C Storage ◽

C Stocks ◽

Mineral Soils ◽

Forest Floors

The extent of carbon (C) storage in forests and the change in C stocks after harvesting are important considerations in the management of greenhouse gases. We measured changes in C storage over time (from postharvest, postburn, year 5, year 10 and year 20) in logging slash, forest floors, mineral soils and planted lodgepole pine (Pinus contorta var. latifolia) trees from six prescribed-burn plantations in north central British Columbia. After harvest, site C in these pools averaged 139 Mg ha-1, with approximately equal contributions from mineral soils (0–30 cm), forest floors and logging slash. Together these detrital pools declined by 71 Mg C ha-1, or 51% (28% directly from the broadcast burn, and a further 23% postburn), in the subsequent 20 yr. Postburn decay in logging slash was inferred by reductions in wood density (from 0.40 to 0.34 g cm-3), equal to an average k rate of 0.011 yr-1. Losses in forest floor C, amounting to more than 60% of the initial mass, were immediate and continued to year 5, with no reaccumulation evident by year 20. Mineral soil C concentrations initially fluctuated before declining by 25% through years 10 and 20. Overall, the reductions in C storage were offset by biomass accumulation of lodgepole pine, and we estimate these plantations had become a net sink for C before year 20, although total C storage was still less than postharvest levels. Key words: C sequestration, forest floors; coarse woody debris; soil organic matter

Download Full-text

Soil development rates from an optically stimulated luminescence-dated beach ridge sequence in Northern Jutland, Denmark

Canadian Journal of Soil Science ◽

10.4141/cjss09020 ◽

2010 ◽

Vol 90 (2) ◽

pp. 295-307 ◽

Cited By ~ 6

Author(s):

A H Nielsen ◽

B. Elberling ◽

M. Pejrup

Keyword(s):

Mineral Soil ◽

C Sequestration ◽

Soil Development ◽

Optically Stimulated Luminescence ◽

Osl Dating ◽

Beach Ridge ◽

Soil C ◽

Development Rates ◽

C Stocks ◽

Osl Age

Rates of podzolic soil development in sandy, temperate soils were quantified based on 14 soil pedons with five substrata from a beach ridge chronosequence near Jerup, Northern Denmark (57°N). Soil pH, organic carbon (C) as well as extractable iron (Fe) and aluminium (Al) were measured. The age of each pedon and soil stratum was measured by optically stimulated luminescence (OSL) dating and used to estimate soil development rates. Soils were divided into five groups from Typic Haplorthods and Entic Alorthods with a mean OSL age of 2965 ± 294 yr to Typic Quartzipsamments with a mean OSL age of 22 ± 11 yr. Acidification rates during the first 200 yr were ~1.9 pH units per 100 yr in the A horizons and C-sequestration rates were ~25 g C m-2 yr-1 (excluding litter accumulation). After ~1500 yr, the mineral soil C stocks stabilised around 13.0 ± 2.0 kg C m-2. Translocation rates of Al into B horizons were ~0.3 kg Al m-2 per 1000 yr, while translocation rates for Fe were scattered. Our study illustrates the potential of OSL dating in chronosequence studies to quantify soil development rates.Key words: Soil development rates, chronosequence, OSL-dating, C-sequestration rates and translocation rates

Download Full-text

The potential for full inversion tillage to increase soil carbon storage following pasture renewal in New Zealand

10.5194/egusphere-egu2020-13082 ◽

2020 ◽

Author(s):

Mike Beare ◽

Erin Lawrence-Smith ◽

Denis Curtin ◽

Sam McNally ◽

Frank Kelliher ◽

...

Keyword(s):

New Zealand ◽

Management Practices ◽

Management Practice ◽

Mineral Soil ◽

C Sequestration ◽

Atmospheric Concentration ◽

Soil C ◽

C Stocks ◽

Soil C Sequestration ◽

Accumulation Efficiency

The global atmospheric concentration of CO2 and other greenhouse gases (GHG) is steadily increasing. It is estimated that, worldwide, soil C sequestration could offset GHG emissions by 400&#8211;1200 Mt C per year. Relative to 1990, New Zealand&#8217;s CH4 and N2O emissions in 2013 had increased by 7% and 23% respectively, which translates to an annual emission increase of 1.09 Mt C that could be offset by a similar annual increase in soil C stock. Recent research has shown that some New Zealand pastoral soils are under-saturated in SOC. Subsurface soils (15&#8211;30 cm depth) typically have a greater soil C saturation deficit than topsoil (0-30 cm) because plant C inputs (roots) are lower. Using management practices that expose more of the under-saturated soil to higher C inputs could result in increased soil C storage and stabilisation.Pasture renewal (destruction and re-establishment of pasture) is promoted to livestock farmers to improve pasture performance. This typically involves shallow cultivation or direct drilling to establish new grass. Whereas shallow cultivation of soil typically results in a loss of SOC, deeper full inversion tillage (FIT) of soil would result in the burial of C-rich topsoil in closer proximity to mineral material that has a higher stabilisation capacity.&#160; Buried SOC is expected to have a slower decomposition rate owing to less variable temperatures and more anoxic conditions. Deep FIT would also bring under-saturated mineral soil to the surface, where the deposition of SOC from high producing pastures could increase the stabilisation of SOC.&#160; Both the slower turnover of buried SOM and greater stabilisation of new carbon on under-saturated minerals at the soil surface are expected to result in increased SOC sequestration. There is a lack of experimental data to directly address the effect of FIT on soil C stocks in pastoral soils. We applied a simple empirical model to predicting changes in soil C stocks following a one-off application of FIT (30 cm) during pasture renewal. The model accounts for the decomposition of SOC in buried topsoil and the accumulation of C in the new topsoil (inverted subsoil). The model was used to derive national estimates of soil C sequestration under different scenarios of C accumulation efficiency, farmer adoption of FIT and pasture renewal rates.Our modelled estimates suggest that 32 Mt C could be sequestered over 20 years following a one-time application of FIT (0-30 cm) to 2 M ha of High Producing Grasslands on suitable New Zealand soils. This estimate is based on 100% accumulation efficiency (i.e. topsoil C stocks are returned to pre-inversion levels within 20 years) and a 10% annual rate of pasture renewal. In the absence of direct experimental evidence, a more conservative estimate is warranted, where topsoil C stocks are projected to return to 80% of pre-inversion levels, thus sequestering 20 Mt C. This paper will present our modelled estimates of SOC sequestration during FIT pasture renewal and discuss the potential benefits and adverse effects of deploying this management practice.

Download Full-text

Evaluation of forest management effects on the mineral soil carbon pool of a lowland, mixed-species forest in Maine, USA

Canadian Journal of Soil Science ◽

10.1139/cjss-2015-0136 ◽

2016 ◽

Vol 96 (2) ◽

pp. 207-218 ◽

Cited By ~ 9

Author(s):

Joshua J. Puhlick ◽

Ivan J. Fernandez ◽

Aaron R. Weiskittel

Keyword(s):

Forest Management ◽

Management Strategies ◽

Mineral Soil ◽

Primary Objective ◽

Significant Treatment ◽

Soil C ◽

C Storage ◽

C Stocks ◽

C Stock ◽

Post Hoc

Concerns about climate change have increased interest in ways to maximize carbon (C) storage in forests through the use of alternative forest management strategies. However, the influence of these strategies on soil C pools is unclear. The primary objective of this study was to test for differences in mineral soil C stocks among various silvicultural and harvesting treatments that were initiated in the 1950s and have been maintained since on the Penobscot Experimental Forest in central Maine, USA. Five mineral soil cores below the surface organic horizon to a depth of 1 m were collected from each replicate (n = 2) of selection, shelterwood, and commercial clearcut treatments. For these treatments, the mean mineral soil C stock was 47.7 ± 16.4 Mg ha−1 (mean ± SD). We found no significant differences in average mineral soil C stocks among treatments. However, a post hoc power analysis indicated that the probability of detecting a significant treatment effect was only 6%. We determined that 98 stands per treatment would be required to be 80% certain that the F test would detect a difference in average mineral soil C stocks whenever any pair of treatments had C stocks differing by more than 5 Mg ha−1.

Download Full-text

Continuous and discontinuous variation in ecosystem carbon stocks with elevation across a treeline ecotone

Biogeosciences Discussions ◽

10.5194/bgd-11-15435-2014 ◽

2014 ◽

Vol 11 (11) ◽

pp. 15435-15461

Author(s):

J. D. M. Speed ◽

V. Martinsen ◽

A. J. Hester ◽

Ø. Holand ◽

J. Mulder ◽

...

Keyword(s):

Large Scale ◽

Mineral Soil ◽

Livestock Grazing ◽

Treeline Ecotone ◽

Soil C ◽

C Storage ◽

C Stocks ◽

C Stock ◽

The Impact ◽

Forest Line

Abstract. Treelines differentiate vastly contrasting ecosystems: open tundra from closed forest. Treeline advance has implications for the climate system due to the impact of the transition from tundra to forest ecosystem on carbon (C) storage and albedo. Treeline advance has been seen to increase above-ground C stocks as low vegetation is replaced with trees, but decrease organic soil C stocks as old carbon is decomposed. However, studies comparing across the treeline typically do not account for elevational variation within the ecotone. Here we sample ecosystem C stocks along an elevational gradient (970 to 1300 m), incorporating a large-scale and long-term livestock grazing experiment, in the Southern Norwegian mountains. We investigate whether there are continuous or discontinuous changes in C storage across the treeline ecotone, and whether these are modulated by grazing. We find that vegetation C stock decreases with elevation, with a clear breakpoint between the forest line and treeline above which the vegetation C stock is constant. In contrast, C stocks in organic surface horizons of the soil increase linearly with elevation within the study's elevational range, whereas C stocks in mineral soil horizons are unrelated to elevation. Total ecosystem C stocks also showed a discontinuous elevational pattern, increasing with elevation above the treeline (8 g m−2 m−1 increase in elevation), but decreasing with elevation below the forest line (−15 g m−2 m−1 increase in elevation), such that ecosystem C storage reaches a minimum between the forest line and treeline. We did not find any effect of short-term (12 years) grazing on the elevational patterns. Our findings demonstrate that patterns of C storage across the treeline are complex, and should be taken account of when estimating ecosystem C storage with shifting treelines.

Download Full-text

Modeling Experiments for Evaluating the Effects of Trees, Increasing Temperature, and Soil Texture on Carbon Stocks in Agroforestry Systems in Kerala, India

Forests ◽

10.3390/f10090803 ◽

2019 ◽

Vol 10 (9) ◽

pp. 803

Author(s):

Ann E. Russell ◽

B. Mohan Kumar

Keyword(s):

Soil Texture ◽

Growth Form ◽

C Sequestration ◽

Agroforestry Systems ◽

Individual Factors ◽

Agricultural Systems ◽

Soil C ◽

C Storage ◽

C Stocks ◽

Increasing Temperature

Research Highlights: Agroforestry systems in the humid tropics have the potential for high rates of production and large accumulations of carbon in plant biomass and soils and, thus, may play an important role in the global C cycle. Multiple factors can influence C sequestration, making it difficult to discern the effect of a single factor. We used a modeling approach to evaluate the relative effects of individual factors on C stocks in three agricultural systems in Kerala, India. Background and Objectives: Factors such as plant growth form, management, climate warming, and soil texture can drive differences in C storage among cropping systems, but the relationships among these factors and their effects are complex. Our objective was to use CENTURY, a process-based model of plant–soil nutrient cycling, in an experimental mode to evaluate the effects of individual factors on C stocks in soil and biomass in monocultures (annuals or trees) and agroforestry systems. Materials and Methods: We parameterized the model for this region, then conducted simulations to investigate the effects on C stocks of four experimental scenarios: (1) change in growth form; (2) change in tree species; (3) increase in temperature above 20-year means; and (4) differences in soil texture. We compared the models with measured changes in soil C after eight years. Results: Simulated soil C stocks were influenced by all factors: growth form; lignin in tree tissues; increasing temperature; and soil texture. However, increasing temperature and soil sand content had relatively small effects on biomass C. Conclusions: Inclusion of trees with traits that promoted C sequestration such as lignin content, along with the use of best management practices, resulted in the greatest C storage among the simulated agricultural systems. Greater use and better management of trees with high C-storage potential can thus provide a low-cost means for mitigation of climate warming.

Download Full-text

Organic carbon stocks in Mediterranean soil types under different land uses (Southern Spain)

Solid Earth ◽

10.5194/se-3-375-2012 ◽

2012 ◽

Vol 3 (2) ◽

pp. 375-386 ◽

Cited By ~ 74

Author(s):

M. Muñoz-Rojas ◽

A. Jordán ◽

L. M. Zavala ◽

D. De la Rosa ◽

S. K. Abd-Elmabod ◽

...

Keyword(s):

Climate Change ◽

Land Use ◽

Arable Land ◽

C Sequestration ◽

Southern Spain ◽

Organic C ◽

Soil C ◽

C Stocks ◽

Mediterranean Systems ◽

Land Use And Management

Abstract. Soil C sequestration through changes in land use and management is one of the sustainable and long-term strategies to mitigate climate change. This research explores and quantifies the role of soil and land use as determinants of the ability of soils to store C along Mediterranean systems. Detailed studies of soil organic C (SOC) dynamics are necessary in order to identify factors determining fluctuations and intensity of changes. In this study, SOC contents from different soil and land use types have been investigated in Andalusia (Southern Spain). We have used soil information from different databases, as well as land use digital maps, climate databases and digital elevation models. The average SOC content for each soil control section (0–25, 25–50 and 50–75 cm) was determined and SOC stocks were calculated for each combination of soil and land use type, using soil and land cover maps. The total organic C stocks in soils of Andalusia is 415 Tg for the upper 75 cm, with average values ranging from 15.9 Mg C ha−1 (Solonchaks under "arable land") to 107.6 Mg C ha−1 (Fluvisols from "wetlands"). Up to 55% of SOC accumulates in the top 25 cm of soil (229.7 Tg). This research constitutes a preliminary assessment for modelling SOC stock under scenarios of land use and climate change.

Download Full-text

Higher stand densities can promote soil carbon storage after conversion of temperate mixed natural forests to larch plantations

European Journal of Forest Research ◽

10.1007/s10342-020-01346-9 ◽

2020 ◽

Author(s):

Meng Na ◽

Xiaoyang Sun ◽

Yandong Zhang ◽

Zhihu Sun ◽

Johannes Rousk

Keyword(s):

Forest Management ◽

Soil Carbon ◽

Stand Density ◽

C Sequestration ◽

Tree Density ◽

Natural Forests ◽

Soil C ◽

C Storage ◽

Soil C Storage ◽

Soil C Sequestration

AbstractSoil carbon (C) reservoirs held in forests play a significant role in the global C cycle. However, harvesting natural forests tend to lead to soil C loss, which can be countered by the establishment of plantations after clear cutting. Therefore, there is a need to determine how forest management can affect soil C sequestration. The management of stand density could provide an effective tool to control soil C sequestration, yet how stand density influences soil C remains an open question. To address this question, we investigated soil C storage in 8-year pure hybrid larch (Larix spp.) plantations with three densities (2000 trees ha−1, 3300 trees ha−1 and 4400 trees ha−1), established following the harvesting of secondary mixed natural forest. We found that soil C storage increased with higher tree density, which mainly correlated with increases of dissolved organic C as well as litter and root C input. In addition, soil respiration decreased with higher tree density during the most productive periods of warm and moist conditions. The reduced SOM decomposition suggested by lowered respiration was also corroborated with reduced levels of plant litter decomposition. The stimulated inputs and reduced exports of C from the forest floor resulted in a 40% higher soil C stock in high- compared to low-density forests within 8 years after plantation, providing effective advice for forest management to promote soil C sequestration in ecosystems.

Download Full-text

Comparison of carbon and nitrogen storage in mineral soils of graminoid and shrub tundra sites, western Greenland

Arctic Science ◽

10.1139/as-2015-0023 ◽

2016 ◽

Vol 2 (4) ◽

pp. 165-182 ◽

Cited By ~ 5

Author(s):

Chelsea L. Petrenko ◽

Julia Bradley-Cook ◽

Emily M. Lacroix ◽

Andrew J. Friedland ◽

Ross A. Virginia

Keyword(s):

Vegetation Type ◽

Mineral Soil ◽

Biotic Interactions ◽

The Arctic ◽

Soil C ◽

N Storage ◽

C Storage ◽

Arctic Soils ◽

C Pools ◽

C And N

Shrub species are expanding across the Arctic in response to climate change and biotic interactions. Changes in belowground carbon (C) and nitrogen (N) storage are of global importance because Arctic soils store approximately half of global soil C. We collected 10 (60 cm) soil cores each from graminoid- and shrub-dominated soils in western Greenland and determined soil texture, pH, C and N pools, and C:N ratios by depth for the mineral soil. To investigate the relative chemical stability of soil C between vegetation types, we employed a novel sequential extraction method for measuring organo-mineral C pools of increasing bond strength. We found that (i) mineral soil C and N storage was significantly greater under graminoids than shrubs (29.0 ± 1.8 versus 22.5 ± 3.0 kg·C·m−2 and 1.9 ± .12 versus 1.4 ± 1.9 kg·N·m−2), (ii) chemical mechanisms of C storage in the organo-mineral soil fraction did not differ between graminoid and shrub soils, and (iii) weak adsorption to mineral surfaces accounted for 40%–60% of C storage in organo-mineral fractions — a pool that is relatively sensitive to environmental disturbance. Differences in these C pools suggest that rates of C accumulation and retention differ by vegetation type, which could have implications for predicting future soil C pool storage.

Download Full-text