Fire suppression and ecosystem carbon storage
TL;DR: A 35-year controlled burning experiment in Minnesota oak savanna showed that fire frequency had a great impact on ecosystem carbon (C) stores, with most carbon stored in woody biomass.
Abstract: A 35-year controlled burning experiment in Minnesota oak savanna showed that fire frequency had a great impact on ecosystem carbon (C) stores. Specifically, compared to the historical fire regime, fire suppression led to an average of 1.8 Mg·ha−1·yr−1 of C storage, with most carbon stored in woody biomass. Forest floor carbon stores were also significantly impacted by fire frequency, but there were no detectable effects of fire suppression on carbon in soil and fine roots combined, or in woody debris. Total ecosystem C stores averaged ∼110 Mg/ha in stands experiencing presettlement fire frequencies, but ∼220 Mg/ha in stands experiencing fire suppression. If comparable rates of C storage were to occur in other ecosystems in response to the current extent of fire suppression in the United States, fire suppression in the USA might account for 8–20% of missing global carbon.
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TL;DR: In this paper, a machine learning analysis using random forests was performed in a spatio-temporal data set comprising a large number of savanna fires across 22 years and the results indicated that fire return interval was not an important predictor of fire spread rate or fire intensity, having a feature importance of 3.5%.
Abstract: Fire has been an integral part of the Earth for millennia. Several recent wildfires have exhibited an unprecedented spatial and temporal extent and their control is beyond national firefighting capabilities. Prescribed or controlled burning treatments are debated as a potential measure for ameliorating the spread and intensity of wildfires. Machine learning analysis using random forests was performed in a spatio-temporal data set comprising a large number of savanna fires across 22 years. Results indicate that fire return interval was not an important predictor of fire spread rate or fire intensity, having a feature importance of 3.5%, among eight other predictor variables. Manipulating burn seasonality showed a feature importance of 6% or less regarding fire spread rate or fire intensity. While manipulated fire return interval and seasonality moderated both fire spread rate and intensity, their overall effects were low in comparison with meteorological (hydrological and climatic) variables. The variables with the highest feature importance regarding fire spread rate resulted in fuel moisture with 21%, relative humidity with 15%, wind speed with 14%, and last years rainfall with 14%. The variables with the highest feature importance regarding fire intensity included fuel load with 21.5%, fuel moisture with 16.5%, relative humidity with 12.5%, air temperature with 12.5%, and rainfall with 12.5%. Predicting fire spread rate and intensity has been a poor endeavour thus far and we show that more data of the variables already monitored would not result in higher predictive accuracy.
3 citations
TL;DR: In this article, the recovery pattern of carbon pools in terms of size and the relative contribution of each pool to total ecosystem C along a fire chronosequence of tropical mixed pine-hardwood forest was analyzed.
Abstract: Aim of the study : To analyze the recovery pattern of carbon pools in terms of size and the relative contribution of each pool to total ecosystem C along a fire chronosequence of tropical mixed pine-hardwood forest. Area of the study : Las Joyas Research Station (LJRS), core zone of Sierra de Manantlan Biosphere Reserve (SMBR) in the state of Jalisco, central western Mexico. Materials and methods : Carbon stored in aboveground plant biomass, standing dead trees, downed woody debris, forest floor, fine roots and mineral soil, was compared with a nested analysis of variance (ANOVA) in post-fire stands of eight-year-old, 28- and 60-year-old stands of mixed Pinus douglasiana -hardwood forest. Main results : The total ecosystem carbon in eight-year-old stands was 50% lower than that of 60-year-old stands. Carbon content in the biomass and mineral soil increased with stand age. The carbon in the biomass recovered to the undisturbed forest in the 28 years of succession. The main C storage in the eight-year-old stands were the mineral soil (64%) and downed woody debris (18%), while in the 28- and 60-year-old stands, live tree biomass and mineral soil were the two largest components of the total C pool (43% and 46%, respectively). Research highlights : We found a significant effect of high-severity fire events on ecosystem C storage and a shift in carbon distribution. The relatively fast recovery of C in ecosystem biomass suggests that mixed Pinus douglasiana hardwood forest possess functional traits that confer resilience to severe fire events. Key words: chronosequence; carbon dynamics; mineral soil; Pinus douglasiana ; fire effects. Abbreviations used : LJRS, Las Joyas Research Station; DBH, diameter at breast height; DL, duff layer; LL, litter layer; DWD, downed woody debris; ANOVA, analysis of variance; CO 2 , carbon dioxide; SMBR, Sierra de Manantlan Biosphere Reserve; C, carbon. AGV, above ground vegetation.
3 citations
Cites background from "Fire suppression and ecosystem carb..."
...Therefore, has been a common perception that fire suppression decrease the rate of release of CO2 caused by burning and maximize C storage in ecosys tem pools (Tilman et al., 2000; Hurteau & Brooks, 2011)....
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TL;DR: In this paper, the characteristics of fire regimes that prevent or reverse woody plant encroachment, maintain native species richness and minimise exotic plant invasion in temperate grassland at the Surrey Hills Tasmania, where a fire management plan with variable prescriptions had been implemented for two decades.
Abstract: Natural temperate grasslands are endangered throughout their range, largely because of their almost complete conversion to agriculture, and by changes in fire and grazing regimes. Woody encroachment by shrubs is a global threat to the structure, function and composition of grasslands. We wished to determine the characteristics of fire regimes that prevent or reverse woody plant encroachment, maintain native species richness and minimise exotic plant invasion in temperate grassland at the Surrey Hills Tasmania, where a fire management plan with variable prescriptions had been implemented for two decades. We collected floristic, fire regime and environmental data from 105 quadrats (1 × 10 m) in 2016/2017, and compared the data from 2016/2017 to that from a 1994 survey using the same methods. A high frequency and cover of native shrubs characterised areas unburned for at least 20 years before 2017, but not those unburned in the 20 years before 1994. Shrub cover began to strongly increase after a decade without fire and was greater on larger plains. Native species richness declined with an increasing minimum interval between fires and increased with elevation. It began to decline at the quadrat scale when shrub cover attained 40%. In the data set as a whole, 17 of the 67 most abundant taxa were absent from all quadrats unburned for 20 years before 2017, indicating a high potential for loss of species at a landscape scale in the absence of fire. Exotic species cover was randomly distributed in relation to fire regimes and environment. The current fire management regime has largely been at a sufficient frequency and minimum interval (approximately a decade between fires) to maintain the grassiness and native species richness of treated plains, which is fortunate given that recent land-use change appears to have resulted in increased frequency of shrubs independent of their cover.
3 citations
TL;DR: In this paper, the authors used a 29-yr fire occurrence database to show how spatial variance changes with respect to grain as postulated by Wiens (1989) when reporting fire patterns within the Great Plains, USA.
Abstract: The emergence of large-scale fire classifications and products informed by remote sensing data has enabled opportunities to include variability or heterogeneity as part of modern fire regime classifications. Currently, basic fire metrics such as mean fire return intervals are calculated without considering spatial variance in a management context. Fire return intervals are also only applicable at a particular grain size (defined as the spatial unit of interest) even though they are typically applied homogeneously. In this study, we utilized a 29-yr fire occurrence database to show how spatial variance changes with respect to grain as postulated by Wiens (1989) when reporting fire patterns within the Great Plains, USA. We utilized data from the Monitoring Trends in Burn Severity database of fire occurrence for the years 1984–2012. We analyzed median numbers of fire along with their variance at four spatial grains ranging from small units (e.g., plots at 3 9 3 km resolution) to large units (e.g., landscapes at 1500 9 2700 km resolution). Median number of fire occurrences was consistently low, irrespective of grain. Despite the consistency in low median numbers of fires across grain, variance in the numbers of fires between units decreased. Variance within units, however, did not change as grain increased indicating fire-pattern-scale inconsistencies. Fire pattern interpretations depended entirely on the scale at which it is calculated. Given that the Great Plains region has a large disparity in fire patterns (i.e., some regions burn often, while others may never burn), fire regime classifications will benefit from including scale-specific variance estimates as a foundation for understanding changes in fire regimes and corresponding social–ecological and policy responses.
3 citations
01 Jan 2009
3 citations
Cites background from "Fire suppression and ecosystem carb..."
...Hardwood forests can be dominated by early and mid-successional species like oak and pine with a constant exposure to fire (Tilman et al., 2000; Black et al., 2006) Palynologic studies can be successfully used to reconstruct the vegetation history, including the external disturbances on flora in…...
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...Extrapolation of Stalagmite δ13Ccalc δ13Ccalc records of the BCC-002 calcite stalagmites were reconstructed based on the assumption that stalagmite Sr/Ca ratios positively correlate with δ13Ccalc when drip water residence times and CO2 degassing rates depend on the local climate....
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...The amount of vegetation cover can also affect the carbon dioxide partial pressure (PCO2) in soils....
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...Carbon content in a burnt soil forest floor can be lowered up to 9% compared to un-burnt soil (Tilman et al., 2000)....
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...Absence of vegetation can decrease the soil carbon dioxide partial pressure compared to the cave PCO2 and decrease or cease stalagmite growth (Baldini et al., 2008)....
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References
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Book•
06 Mar 1997
TL;DR: In this paper, the authors present a perspective of the global cycle of nitrogen and phosphorous, the global water cycle, and the global sulfur cycle from a global point of view.
Abstract: Part 1 Processes and reactions: origins the atmosphere the lithosphere the terrestrial biosphere biogeochemical cycling on land biogeochemistry in freshwater wetlands and lakes rivers and estuaries the sea. Part 2 Global cycles: the global water cycle the global carbon cycle the global cycle of nitrogen and phosphorous the global sulfur cycle a perspective.
3,871 citations
TL;DR: Slowing deforestation, combined with an increase in forestation and other management measures to improve forest ecosystem productivity, could conserve or sequester significant quantities of carbon.
Abstract: Forest systems cover more than 4.1 x 109 hectares of the Earth9s land area. Globally, forest vegetation and soils contain about 1146 petagrams of carbon, with approximately 37 percent of this carbon in low-latitude forests, 14 percent in mid-latitudes, and 49 percent at high latitudes. Over two-thirds of the carbon in forest ecosystems is contained in soils and associated peat deposits. In 1990, deforestation in the low latitudes emitted 1.6 ± 0.4 petagrams of carbon per year, whereas forest area expansion and growth in mid- and high-latitude forest sequestered 0.7 ± 0.2 petagrams of carbon per year, for a net flux to the atmosphere of 0.9 ± 0.4 petagrams of carbon per year. Slowing deforestation, combined with an increase in forestation and other management measures to improve forest ecosystem productivity, could conserve or sequester significant quantities of carbon. Future forest carbon cycling trends attributable to losses and regrowth associated with global climate and land-use change are uncertain. Model projections and some results suggest that forests could be carbon sinks or sources in the future.
3,175 citations
"Fire suppression and ecosystem carb..." refers background or methods in this paper
...…biomass creates ;20–25% of annual anthropogenic CO2 (Andreae 1991, Schimel 1995), modifications of fire frequency may significantly change regional and global C budgets (e.g., Fahenstock and Agee 1983, Andreae 1991, Stocks 1991, Dixon and Krankina 1993, Dixon et al. 1994, Sohngen and Haynes 1997)....
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...This work was supported by National Science Foundation Grant 9411972 and by the Andrew Mellon Foundation....
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...Our work supports the proposal that increased fire suppression and decreased anthropogenic burning of vegetation could significantly influence global carbon dynamics (Dixon et al. 1994, Sampson and Clark 1995, Sohngen and Haynes 1997, San Jose et al. 1998)....
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...Dixon et al. (1994) calculated that fire management in Russia could lead to long-term C storage of 0.6 3 1015 g C/yr....
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TL;DR: The terrestrial biosphere plays an important role in the global carbon cycle as mentioned in this paper, which is the fluxes of carbon among four main reservoirs: fossil carbon, the atmosphere, the oceans, and the terrestrial Biosphere.
Abstract: The terrestrial biosphere plays an important role in the global carbon cycle. In the 1994 Intergovernmental Panel Assessment on Climate Change (IPCC), an effort was made to improve the quantification of terrestrial exchanges and potential feedbacks from climate, changing CO2, and other factors; this paper presents the key results from that assessment, together with expanded discussion. The carbon cycle is the fluxes of carbon among four main reservoirs: fossil carbon, the atmosphere, the oceans, and the terrestrial biosphere. Emissions of fossil carbon during the 1980s averaged 5.5 Gt y−1. During the same period, the atmosphere gained 3.2 Gt C y−1 and the oceans are believed to have absorbed 2.0 Gt C y−1. The regrowing forests of the Northern Hemisphere may have absorbed 0.5 Gt C y−1 during this period. Meanwhile, tropical deforestation is thought to have released an average 1.6 Gt C y−1 over the 1980s. While the fluxes among the four pools should balance, the average 198Ds values lead to a ‘missing sink’ of 1.4 Gt C y−1 Several processes, including forest regrowth, CO2 fertilization of plant growth (c. 1.0 Gt C y−1), N deposition (c. 0.6 Gt C y−1), and their interactions, may account for the budget imbalance. However, it remains difficult to quantify the influences of these separate but interactive processes. Uncertainties in the individual numbers are large, and are themselves poorly quantified. This paper presents detail beyond the IPCC assessment on procedures used to approximate the flux uncertainties.
Lack of knowledge about positive and negative feedbacks from the biosphere is a major limiting factor to credible simulations of future atmospheric CO2 concentrations. Analyses of the atmospheric gradients of CO2 and 13 CO2 concentrations provide increasingly strong evidence for terrestrial sinks, potentially distributed between Northern Hemisphere and tropical regions, but conclusive detection in direct biomass and soil measurements remains elusive.
Current regional-to-global terrestrial ecosystem models with coupled carbon and nitrogen cycles represent the effects of CO2 fertilization differently, but all suggest longterm responses to CO2 that are substantially smaller than potential leaf- or laboratory whole plant-level responses. Analyses of emissions and biogeochemical fluxes consistent with eventual stabilization of atmospheric CO2 concentrations are sensitive to the way in which biospheric feedbacks are modeled by c. 15%. Decisions about land use can have effects of 100s of Gt C over the next few centuries, with similarly significant effects on the atmosphere.
Critical areas for future research are continued measurements and analyses of atmospheric data (CO2 and 13CO2) to serve as large-scale constraints, process studies of the scaling from the photosynthetic response to CO2 to whole-ecosystem carbon storage, and rigorous quantification of the effects of changing land use on carbon storage.
1,510 citations
"Fire suppression and ecosystem carb..." refers background or methods in this paper
...2680 Key words: carbon storage; fire suppression; missing carbon; oak savanna....
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...San Jose et al. (1998) calculated that fire suppression, by causing the transformation of the 2.8 3 107 ha Venezuelan Orinoco Llanos from grassland to semideciduous forest, could lead to a C sink of 0.08 3 1015 g C/yr....
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...Atmospheric CO2 is currently accumulating at ;3.2 3 1015 g C/yr (Schimel 1995)....
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...Dixon et al. (1994) calculated that fire management in Russia could lead to long-term C storage of 0.6 3 1015 g C/yr....
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...Because the burning of ecosystem biomass creates ;20–25% of annual anthropogenic CO2 (Andreae 1991, Schimel 1995), modifications of fire frequency may significantly change regional and global C budgets (e.g., Fahenstock and Agee 1983, Andreae 1991, Stocks 1991, Dixon and Krankina 1993, Dixon et al.…...
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TL;DR: The first edition of Schlesinger's Biogeochemistry in 1991 was an early entry in the field of Earth system science/global change, and has since gained sufficient popularity and demand to merit a second, extensively revised edition.
Abstract: Compared to the well-established disciplines, the field of Earth system science/global change has relatively few books from which to choose. Of the small subset of books dealing specifically with biogeochemical aspects of global change, the first edition of Schlesinger's Biogeochemistry in 1991 was an early entry. It has since gained sufficient popularity and demand to merit a second, extensively revised edition.
The first part of the book provides a general introduction to biogeochemistry and cycles, and to the origin of elements, our planet, and life on Earth. It then describes the functioning and biogeochemistry of the atmosphere, lithosphere, biosphere, and hydrosphere, including marine and freshwater systems. Although system function and features are stressed, the author begins to introduce global change topics, such as soil organic matter and global change in Chapter 5, and landscape and mass balance in Chapter 6.
1,075 citations
"Fire suppression and ecosystem carb..." refers background or methods in this paper
...This work was supported by National Science Foundation Grant 9411972 and by the Andrew Mellon Foundation....
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...Moreover, the immense global extent of tropical savanna and woodland, 2.45 3 109 ha (Schlesinger 1997), suggests that even moderate fire suppression in this ecosystem type could provide a globally significant C sink....
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TL;DR: The rates at which lands in the United States were cleared for agriculture, abandoned, harvested for wood, and burned were reconstructed from historical data for the period 1700-1990 and used in a terrestrial carbon model to calculate annual changes in the amount of carbon stored in terrestrial ecosystems, including wood products.
Abstract: The rates at which lands in the United States were cleared for agriculture, abandoned, harvested for wood, and burned were reconstructed from historical data for the period 1700-1990 and used in a terrestrial carbon model to calculate annual changes in the amount of carbon stored in terrestrial ecosystems, including wood products. Changes in land use released 27 +/- 6 petagrams of carbon to the atmosphere before 1945 and accumulated 2 +/- 2 petagrams of carbon after 1945, largely as a result of fire suppression and forest growth on abandoned farmlands. During the 1980s, the net flux of carbon attributable to land management offset 10 to 30 percent of U.S. fossil fuel emissions.
1,035 citations
"Fire suppression and ecosystem carb..." refers background or methods in this paper
...Houghton et al. (1999) estimated various sources of C storage in the United States....
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...Because fire suppression might lead to a period of C accumulation (Houghton et al. 1999), current fire suppression in the United States (Fig....
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...This work was supported by National Science Foundation Grant 9411972 and by the Andrew Mellon Foundation....
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...2680 Key words: carbon storage; fire suppression; missing carbon; oak savanna....
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