Carbon Accumulation and Partitioning Above and Belowground under Coppiced and Replanted Eucalypt Plantations

Abstract The extent to which the C sink strength of eucalypt plantations can be affected by coppicing or replanting remains unclear. To address this issue, we evaluated variations in C stocks under coppiced or replanted eucalypt stands formed by clones or seedlings. For each field assessment (0 [T0], 2.5, 3.5, 4.5, 5.5 and 7.0 years [at harvest]), tree biomass, litterfall, and soil C stocks (0–120 cm depth) were determined. At harvest, debarked stemwood productivity was similar under coppice or replanting, about 50.0 Mg C ha–1. Generally, coppiced stands favored subsoil C storage (40–100 cm), whereas replanted stands favored soil C accrual in topsoil (0–20 cm), depending on the genetic material. Relative to T0, soil C increased about 2.14, 1.91, and 1.84 Mg C ha–1 yr–1 under coppice, replanting with seedlings and clones, respectively. Coarse root biomass under these stands were about 17.3, 13.4, and 9.5 Mg C ha–1, respectively, equivalent to 50% of total harvest residues. Hence, inputs from coarse roots could represent a large contribution to soil C over multiple rotations under coppiced or replanted stands. Otherwise, short-term C losses can be high where stumps and coarse roots are harvested, especially following successive coppice cycles. Study Implications: Our findings have important implications for forest managers growing eucalypt plantations aiming to maximize C accumulation. Both coppiced and replanted stands can fix up to 50 Mg C ha−1 only in debarked stemwood over 7 years, with a comparatively higher C storage in coarse roots under coppice. Despite the increasing demand for forest residues in bioenergy production, harvesting stumps and coarse roots should be avoided, especially upon replanting eucalypt stands after successive coppice cycles.

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

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1719685115 ◽

2018 ◽

Vol 115 (11) ◽

pp. 2776-2781 ◽

Cited By ~ 33

Author(s):

Lucas E. Nave ◽

Grant M. Domke ◽

Kathryn L. Hofmeister ◽

Umakant Mishra ◽

Charles H. Perry ◽

...

Keyword(s):

National Level ◽

Mineral Soil ◽

C Sequestration ◽

The United States ◽

Forest Sector ◽

Soil C ◽

C Storage ◽

C Stocks ◽

The Us ◽

Land Use And Management

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.

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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.

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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

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Effects of seabird nitrogen input on biomass and carbon accumulation after 50 years of primary succession on a young volcanic island, Surtsey

Biogeosciences Discussions ◽

10.5194/bgd-11-6269-2014 ◽

2014 ◽

Vol 11 (5) ◽

pp. 6269-6302 ◽

Cited By ~ 6

Author(s):

N. I. W. Leblans ◽

B. D. Sigurdsson ◽

P. Roefs ◽

R. Thuys ◽

B. Magnússon ◽

...

Keyword(s):

Primary Succession ◽

Soil Depth ◽

Carbon Accumulation ◽

Volcanic Island ◽

N Accumulation ◽

Total N ◽

N Retention ◽

C Storage ◽

C Stocks ◽

N Input

Abstract. What happens during primary succession after the first colonizers have occupied a pristine surface largely depends on how they ameliorate living conditions for other species. For vascular plants the onset of soil development and associated increase in nutrient (mainly nitrogen, N) and water availability is especially important. Here, we report the relation between N accumulation and biomass- and ecosystem carbon (C) stocks in a 50 year old volcanic island, Surtsey, in Iceland, where N stocks are still exceptionally low. However, 27 year old seagull colony on the island provided nutrient-enriched areas, which enabled us to assess the relationship between N stock and biomass- and ecosystem C stocks across a much larger range in N stock. Further, we compared areas on shallow and deep tephra sands as we expected that deep-rooted systems would be more efficient in retaining N. The sparsely vegetated area outside the colony was more efficient in N retention than we expected and had accumulated 0.7 kg N ha−1 yr−1, which was ca. 60% of the estimated N input rate from wet deposition. The seagulls have added, on average, 47 kg N ha−1 yr−1, which induced a shift from belowground to aboveground in ecosystem N and C stocks and doubled the ecosystem "N use efficiency", determined as the ratio of biomass and C storage per unit N input. Soil depth did not significantly affect total N stocks, which suggests a high N retention potential. Both total ecosystem biomass and C stocks were strongly correlated with N stock inside the colony, which indicated the important role of N during the first steps of primary succession. Inside the colony, the ecosystem biomass C stocks (17–27 kg C ha−1) had reached normal values for grasslands, while the soil organic carbon stocks (SOC; 4–10 kg C ha−1) were only a fraction of normal grassland values. Thus, it will take a long time until the SOC stock reaches equilibrium with the current primary production; during which conditions for new colonists may change.

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The impact of harvesting native forests on vegetation and soil C stocks, and soil CO2, N2O and CH4 fluxes

Australian Journal of Botany ◽

10.1071/bt11207 ◽

2011 ◽

Vol 59 (7) ◽

pp. 654 ◽

Cited By ~ 6

Author(s):

K. L. Page ◽

R. C. Dalal ◽

R. J. Raison

Keyword(s):

Primary Production ◽

Time Course ◽

Management Practices ◽

Diverse Range ◽

Soil C ◽

C Storage ◽

Native Forests ◽

C Stocks ◽

Ch4 And N2o ◽

The Impact

Australia’s harvested native forests are extremely diverse in terms of species-mix, disturbance history and ecology, forest productivity and C storage. Our understanding of the effects of harvesting on C storage and greenhouse gas (GHG) emissions from these systems is incomplete, and this paper consolidates current Australian knowledge, places this in a global context, and identifies areas requiring further study. The uptake of CO2 and the re-accumulation of forest C stocks after harvesting or other disturbance is largely dependent on forest primary production. However, in Australian native forests, knowledge of rates of primary production for the diverse range of species and management practices present is poor. Soil respiration rates following harvest have also been largely unquantified for Australian systems. It is essential that both these parameters are quantified if estimates of net ecosystem production (NEP) are to be made. It is generally acknowledged that harvested forests have a negative NEP, and thus are sources of C, immediately following harvest, but attain a positive NEP as the forest regrows and photosynthetic capacity increases. The magnitude and time course of these changes are largely unknown for most Australian forest systems. In addition, little data are available to quantify the effect on soil C storage, and where estimates have been made these are often subject to methodological uncertainty and are thus highly contentious. Following harvest, the changes that occur to soil structure, moisture content, and N cycling may also influence CH4 and N2O flux, although these fluxes also remain largely unquantified in harvested Australian forests. Given the significant changes to NEP, CH4 and N2O fluxes observed after forest harvest in international studies, it is expected that GHG fluxes would typically increase from Australian native forests following harvest, and then slowly decrease over time as biomass accumulates, and N2O and CH4 fluxes return to background levels. However, it is currently difficult to quantify the magnitude and time course of these changes due to a lack of both gas flux and primary production measurements. Clearly, further research effort to quantify these parameters throughout Australia is required in order to obtain a more reliable picture of the effects of harvesting and other disturbances on forest GHG balance.

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Optimal soil carbon sampling designs to achieve cost-effectiveness: a case study in blue carbon ecosystems

Biology Letters ◽

10.1098/rsbl.2018.0416 ◽

2018 ◽

Vol 14 (9) ◽

pp. 20180416 ◽

Cited By ~ 3

Author(s):

Mary A. Young ◽

Peter I. Macreadie ◽

Clare Duncan ◽

Paul E. Carnell ◽

Emily Nicholson ◽

...

Keyword(s):

Soil Depth ◽

Linear Equations ◽

Cost Effective ◽

Blue Carbon ◽

Climate Mitigation ◽

Sampling Effort ◽

Natural Ecosystems ◽

Soil C ◽

C Storage ◽

C Stocks

Researchers are increasingly studying carbon (C) storage by natural ecosystems for climate mitigation, including coastal ‘blue carbon’ ecosystems. Unfortunately, little guidance on how to achieve robust, cost-effective estimates of blue C stocks to inform inventories exists. We use existing data (492 cores) to develop recommendations on the sampling effort required to achieve robust estimates of blue C. Using a broad-scale, spatially explicit dataset from Victoria, Australia, we applied multiple spatial methods to provide guidelines for reducing variability in estimates of soil C stocks over large areas. With a separate dataset collected across Australia, we evaluated how many samples are needed to capture variability within soil cores and the best methods for extrapolating C to 1 m soil depth. We found that 40 core samples are optimal for capturing C variance across 1000's of kilometres but higher density sampling is required across finer scales (100–200 km). Accounting for environmental variation can further decrease required sampling. The within core analyses showed that nine samples within a core capture the majority of the variability and log-linear equations can accurately extrapolate C. These recommendations can help develop standardized methods for sampling programmes to quantify soil C stocks at national scales.

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Soil organic matter turnover rates increase to match increased inputs in grazed grasslands

Biogeochemistry ◽

10.1007/s10533-021-00838-z ◽

2021 ◽

Author(s):

Shane W. Stoner ◽

Alison M. Hoyt ◽

Susan Trumbore ◽

Carlos A. Sierra ◽

Marion Schrumpf ◽

...

Keyword(s):

Climate Change ◽

Management Practice ◽

Turnover Rates ◽

Decomposition Rates ◽

Soil C ◽

C Storage ◽

Trade Offs ◽

Soil Organic Matter Turnover ◽

C Stocks

AbstractManaged grasslands have the potential to store carbon (C) and partially mitigate climate change. However, it remains difficult to predict potential C storage under a given soil or management practice. To study C storage dynamics due to long-term (1952–2009) phosphorus (P) fertilizer and irrigation treatments in New Zealand grasslands, we measured radiocarbon (14C) in archived soil along with observed changes in C stocks to constrain a compartmental soil model. Productivity increases from P application and irrigation in these trials resulted in very similar C accumulation rates between 1959 and 2009. The ∆14C changes over the same time period were similar in plots that were both irrigated and fertilized, and only differed in a non-irrigated fertilized plot. Model results indicated that decomposition rates of fast cycling C (0.1 to 0.2 year−1) increased to nearly offset increases in inputs. With increasing P fertilization, decomposition rates also increased in the slow pool (0.005 to 0.008 year−1). Our findings show sustained, significant (i.e. greater than 4 per mille) increases in C stocks regardless of treatment or inputs. As the majority of fresh inputs remain in the soil for less than 10 years, these long term increases reflect dynamics of the slow pool. Additionally, frequent irrigation was associated with reduced stocks and increased decomposition of fresh plant material. Rates of C gain and decay highlight trade-offs between productivity, nutrient availability, and soil C sequestration as a climate change mitigation strategy.

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Impacts of poplar and alder on soil carbon in pasture-tree systems

NZGA: Research and Practice Series ◽

10.33584/rps.16.2016.3231 ◽

2016 ◽

Vol 16 ◽

pp. 197-202

Author(s):

G.B. Douglas ◽

R.E. Vibart ◽

A.D. Mackay ◽

M.B. Dodd ◽

I.R. Mcivor

Keyword(s):

Carbon Sequestration ◽

Soil Carbon ◽

Greenhouse Gas ◽

Open Systems ◽

Ghg Mitigation ◽

Soil C ◽

Hill Country ◽

C Storage ◽

C Stocks ◽

Significant Difference

Wide-spaced trees on pastoral land (pasture-tree (PT) systems) are a widespread feature of many farmed landscapes. They offer the potential to increase carbon (C) storage, with implications for reducing atmospheric CO2-C. The effect of PT systems on soil C stocks to 1 m depth was determined for trees aged 14-16 years at densities of 73-111 stems per hectare at four North Island sites (two with poplar, two with alder). Across sites, mean soil C concentration was 1.9-8.5% and mean total soil C mass was 120-455 tonnes C/ha. For alder systems, total C mass of PT was 37% less than adjacent pasture (Open) at Poukawa (120 versus 189 tonnes C/ha), whereas at Ruakura, there was no significant difference between systems. Total C mass of PT systems involving poplar did not vary significantly from adjacent Open systems at Tikokino (328 versus 352 tonnes C/ha) and Woodville (154 versus 202 tonnes C/ha). Soil at 0.3-1.0 m depth comprised up to half of total C mass. Results suggested that poplar and alder had different effects on soil C. Keywords: pastoral hill country, wide-spaced trees, carbon sequestration, greenhouse gas (GHG) mitigation

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No change in topsoil carbon levels of Great Britain, 1978–2007

Biogeosciences Discussions ◽

10.5194/bgd-7-2267-2010 ◽

2010 ◽

Vol 7 (2) ◽

pp. 2267-2311 ◽

Cited By ~ 14

Author(s):

P. M. Chamberlain ◽

B. A. Emmett ◽

W. A. Scott ◽

H. I. J. Black ◽

M. Hornung ◽

...

Keyword(s):

Land Use ◽

Great Britain ◽

Land Use Change ◽

Monitoring Program ◽

Vegetation Composition ◽

Soil C ◽

National Monitoring ◽

C Storage ◽

C Stocks ◽

Soil Component

Abstract. Soil is an important store of carbon (C) and there has been recent concern that accelerated loss of carbon from the soil may be reinforcing climate change. There is therefore a need to both track current trends in soil C storage and to identify how soil can contribute to carbon emission reduction targets. Countryside Survey (CS) is an integrated national monitoring program in which vegetation, topsoil, water and land use measurements are made across Great Britain (GB). The soil component of CS is unique as topsoil C concentrations have been measured at three time points (1978, 1998 and 2007) together with topsoil bulk density (2007 only), vegetation composition (all years), and land use (i.e. Broad Habitat, 1998, 2007). The combined dataset allows estimates of change in topsoil C stock over time and the influence of land use change on topsoil C to be investigated. Results indicate that although there was a small increase (8%) in topsoil C concentration between 1978 and 1998 and small decrease (6.5%) between 1998 and 2007, there was no significant change in GB topsoil C concentration (in g kg−1), density (in t ha−1) or stock (in Tg) between 1978 and 2007. Within individual habitats some consistent trends were observed and by examining plots which had consistent vegetation composition since 1978 we demonstrate that land use change was not responsible for the few significant changes that were found. These results are comparable with the few other estimates of recent topsoil C concentration and stock changes in W. Europe, with the exception of a previous study in England and Wales which reported significant topsoil C losses of up to 50% over a similar period. Possible reasons for the contradictory findings are discussed. An extra 220–730 Tg of C would be stored in topsoil C stocks if all GB soils were optimised at the top 5–25% C densities as recorded for each habitat in 2007.

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Elevated CO2 increases plant growth but reduces soil C storage under N limiting conditions

10.5194/egusphere-egu2020-22452 ◽

2020 ◽

Author(s):

Lucia M. Eder ◽

Enrico Weber ◽

Johannes Rousk ◽

Marion Schrumpf ◽

Sönke Zaehle

Keyword(s):

Plant Growth ◽

Root Exudation ◽

Beech Forest ◽

Coarse Roots ◽

Soil System ◽

Soil C ◽

N Nutrition ◽

N Limitation ◽

C Storage ◽

C And N

Rising atmospheric CO2 concentrations may induce or aggravate nitrogen (N) limitation to plant growth. To overcome this limitation, plants may invest their newly assimilated carbon (C) into N acquiring strategies, such as root growth, root exudation or C allocation to mycorrhizal symbionts. These shifts in C allocation can increase the turnover of soil organic matter by stimulating microbial activity. As these processes are poorly quantified, their net effects on ecosystem C storage remain uncertain.To gain a better quantitative understanding of these processes, we assessed the effect of elevated CO2 on plant C and N allocation in a mesocosm experiment. For four months of one growing season, 64 saplings of Fagus sylvatica L. were grown in a natural beech forest topsoil. Plants were exposed to near ambient (390 ppm) or elevated (560 ppm, eCO2) CO2 concentrations at two levels of continuous 13CO2 enrichment (&#948;13C +50 or +150&#8240;). At the end of the experiment, we determined dry biomass, C and N concentrations and isotopic compositions for all leaves, buds, twigs, stems and fine and coarse roots for all plants. For all plants, C and N budgets and the amount of newly incorporated C were evaluated.We found a positive effect of eCO2 on tree growth, with the highest growth response in fine root biomass. In both CO2 treatments, newly fixed C was preferentially allocated to roots compared to other plant compartments, but under eCO2, we found a shift in C allocation patterns towards higher belowground C allocation. These results suggest enhanced plant investments into belowground resource acquisition. Decreased N concentrations in all plant organs of these trees under eCO2 may indicate plant N limitation and suggest that the effect of increased belowground C allocation was insufficient to fulfil the plants N demand. Still, the observed increase in C allocation to microbial biomass in these soils may be a mechanism to enhance plant N nutrition. CO2 concentrations also affected C allocation within the whole plant-soil-system: Under eCO2, more C was stored in tree biomass and less C was stored in soils. Overall, there was no effect of CO2 treatment on total mesocosm C. We will discuss these findings with regard to the N mining hypothesis.

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