scholarly journals Soil respiration in a fire scar chronosequence of Canadian boreal jack pine forest

2009 ◽  
Vol 6 (5) ◽  
pp. 8725-8773
Author(s):  
D. R. Smith ◽  
J. D. Kaduk ◽  
H. Balzter ◽  
M. J. Wooster ◽  
G. N. Mottram ◽  
...  
Keyword(s):  
Soil Respiration ◽  
Forest Fires ◽  
Jack Pine ◽  
Fire Scars ◽  
Exponential Relationship ◽  
Fire Scar ◽  
Young Forest ◽  
C Cycle ◽  
Quantitative Understanding ◽  
Fire Intervals

Abstract. To fully understand the carbon (C) cycle impacts of forest fires, both C emissions during the fire and post-disturbance fluxes need to be considered. The latter are dominated by soil respiration (Rs), which is still subject to large uncertainties. This research investigates Rs in a boreal jack pine fire scar chronosequence at Sharpsand Creek, Ontario, Canada. During two field campaigns in 2006 and 2007, Rs was measured in a chronosequence of fire scars aged between 0 and 59 years since the last fire. Mean Rs per fire scar was adjusted for soil temperature (Ts) and soil moisture (Ms) (denoted RST,M). RST,M ranged from 0.56 μmol CO2/m2/s (32 years post fire) to 8.18 μmol CO2/m2/s (58 years post fire). The coefficient of variation (CV) of RST,M ranged from 20% (16 years post fire) to 56% (58 years post fire). Across the field site, there was a statistically highly significant exponential relationship between Rs adjusted for soil organic carbon (Cs) and Ts (P<0.00001; Q10=2.21) but no effect of Ms on Rs adjusted for Cs and Ts for the range 0.21 to 0.77 volumetric Ms (P=0.702). RST,M decreased significantly (P=0.030) after fire (4 to 8 days post fire) in mature forest, though no significant (P>0.1) difference could be detected between recently burned (4 to 8 days post fire) and unburned young forest. There were significant differences in RST,M between recently burned (4 to 8 days post fire) scar age categories that differed in their burn history, with between-fire intervals of 32 vs. 16 years (P<0.001) and 32 vs 59 years (P=0.044). There was a highly significant exponential increase in RST,M with time since fire (r2=0.999; P=0.006) for the chronosequence 0, 16 and 59 years post fire, and for all these age categories, RST,M was significantly different from one another (P<0.05). The results of this study contribute to a better quantitative understanding of Rs in boreal jack pine fire scars and will facilitate improvements in C cycle modelling. Further work is needed in quantifying autotrophic and heterotrophic contributions to Rs in jack pine systems; in monitoring Rs for extended time periods after fire; and in measuring different fire-prone forest types.

scholarly journals Soil surface CO<sub>2</sub> flux increases with successional time in a fire scar chronosequence of Canadian boreal jack pine forest

2010 ◽  
Vol 7 (5) ◽  
pp. 1375-1381 ◽  
Author(s):  
D. R. Smith ◽  
J. D. Kaduk ◽  
H. Balzter ◽  
M. J. Wooster ◽  
G. N. Mottram ◽  
...  
Keyword(s):  
Forest Fires ◽  
Soil Surface ◽  
Co2 Flux ◽  
Jack Pine ◽  
Future Research ◽  
Fire Scars ◽  
Fire Scar ◽  
C Cycle ◽  
Meta Analyses ◽  
In Fire

Abstract. To fully understand the carbon (C) cycle impacts of forest fires, both C emissions during the fire and post-disturbance fluxes need to be considered. The latter are dominated by soil surface CO2 flux (Fs), which is still subject to large uncertainties. Fire is generally regarded as the most important factor influencing succession in the boreal forest biome and fire dependant species such as jack pine are widespread. In May 2007, we took concurrent Fs and soil temperature (Ts) measurements in boreal jack pine fire scars aged between 0 and 59 years since fire. To allow comparisons between scars, we adjusted Fs for Ts (FsT) using a Q10 of 2. Mean FsT ranged from 0.56 (± 0.30 sd) to 1.94 (± 0.74 sd) μmol CO2 m−2 s−1. Our results indicate a difference in mean FsT between recently burned (4 to 8 days post fire) and non-burned mature (59 years since fire) forest (P < 0.001), though no difference was detected between recently burned (4 to 8 days post fire) and non-burned young (16 years since fire) forest (P = 0.785). There was a difference in mean FsT between previously young (16 years since fire) and intermediate aged (32 years since fire) scars that were both subject to fire in 2007 (P < 0.001). However, there was no difference in mean FsT between mature (59 years since fire) and intermediate aged (32 years since fire) scars that were both subjected to fire in 2007 (P = 0.226). Furthermore, there was no difference in mean FsT between mature (59 years since fire) and young scars (16 years since fire) that were both subjected to fire in 2007 (P = 0.186). There was an increase in FsT with time since fire for the chronosequence 0, 16 and 59 years post fire (P < 0.001). Our results lead us to hypothesise that the autotrophic:heterotrophic soil respiration ratio increases over post-fire successional time in boreal jack pine systems, though this should be explored in future research. The results of this study contribute to a better quantitative understanding of Fs in boreal jack pine fire scars and will facilitate meta-analyses of Fs in fire scar chronosequences.

Fire histories in ponderosa pine forests of Grand Canyon are well supported: reply to Baker

2006 ◽  
Vol 15 (3) ◽  
pp. 439 ◽  
Author(s):  
Peter Z. Fulé ◽  
Thomas A. Heinlein ◽  
W. Wallace Covington
Keyword(s):  
Ponderosa Pine ◽  
Grand Canyon ◽  
Pine Forests ◽  
Fire Scars ◽  
Surface Fire ◽  
Ponderosa Pine Forests ◽  
Fire Scar ◽  
Study Sites ◽  
Fire Intervals ◽  
Old Trees

Fire scars and other paleoecological methods are imperfect proxies for detecting past patterns of fire events. However, calculations of long fire rotations in Grand Canyon ponderosa pine forests by Baker are not convincing in methodology or assumptions compared with fire-scar evidence of frequent surface fires. Patches of severe disturbance are a possible hypothesis to explain the relatively short age structure at the park, where ~12% fewer trees were older than 300 years compared with another unharvested northern Arizona site. However, mapped patterns of old trees as well as the evidence for frequent surface fire from fire scars, charcoal deposition studies, and evolutionary history are more consistent with the dominance of surface fire prior to c. 1880. The most relevant available evidence of fire recurrence at a given point, mean point fire intervals, had median values <16 years at all five study sites, close to filtered composite fire interval statistics (~6–10 years), but much lower than Baker’s calculated fire rotation values (55–110 years). The composite fire interval is not a uniquely important statistic or a numerical guideline for management, but one of many lines of evidence underscoring the ecological role of frequent surface fire in ponderosa pine forests.

Fire history in a Sequoiasempervirens forest at Salt Point State Park, California

1989 ◽  
Vol 19 (11) ◽  
pp. 1451-1457 ◽  
Author(s):  
Mark A. Finney ◽  
Robert E. Martin
Keyword(s):  
Fire History ◽  
Moving Average ◽  
Fire Scars ◽  
Coast Redwood ◽  
Fire Scar ◽  
Point Data ◽  
Substantial Bias ◽  
Fire Intervals ◽  
Redwood Forest ◽  
Composite Data

Fire occurrence data between the 12th and 20th centuries were obtained from analysis of fire scars on coast redwood (Sequoiasempervirens (D. Don.) Endl.) and bishop pine (Pinusmuricata D. Don.). Mean fire intervals were calculated for settlement and presettlement periods from fire scar samples individually (point data) and from composites of samples aggregated within three approximately 200-ha study areas. Mean fire intervals from point data (20.5 to 29.0 years) were more than three times greater than mean intervals from composite data (6.1 to 9.3 years). Mean fire intervals derived from point data compared well with values previously reported, although substantial bias ascribed to point data suggests that these values for mean fire intervals in redwood forest communities are too large. A period of significantly longer fire intervals during the 17th century was suggested by analysis of fire intervals by century and using a moving average.

Comparing methods of reconstructing fire history using fire scars in a southwestern United States ponderosa pine forest

2006 ◽  
Vol 36 (4) ◽  
pp. 855-867 ◽  
Author(s):  
Megan L Van Horne ◽  
Peter Z Fulé
Keyword(s):  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Fire History ◽  
Sampling Methods ◽  
Fire Regime ◽  
Fire Frequency ◽  
Fire Scars ◽  
Fire Scar ◽  
Targeted Sampling ◽  
Fire Intervals

Fire scars have been used to understand the historical role of fire in ponderosa pine (Pinus ponderosa Dougl. ex P. & C. Laws.) ecosystems, but sampling methods and interpretation of results have been criticized for being statistically invalid and biased and for leading to exaggerated estimates of fire frequency. We compared "targeted" sampling, random sampling, and grid-based sampling to a census of all 1479 fire-scarred trees in a 1 km2 study site in northern Arizona. Of these trees, 1246 were sufficiently intact to collect cross-sections; of these, 648 had fire scars that could be cross-dated to the year of occurrence in the 200-year analysis period. Given a sufficient sample size (approximately n ≥ 50), we concluded that all tested sampling methods resulted in accurate estimates of the census fire frequency, with mean fire intervals within 1 year of the census mean. We also assessed three analytical techniques: (1) fire intervals from individual trees, (2) the interval between the tree origin and the first scar, and (3) proportional filtering. "Bracketing" fire regime statistics to account for purported uncertainty associated with targeted sampling was not useful. Quantifying differences in sampling approaches cannot resolve all the limitations of fire-scar methods, but does strengthen interpretation of these data.

Spatial interpolation and mean fire interval analyses quantify historical mixed-severity fire regimes

2017 ◽  
Vol 26 (2) ◽  
pp. 136 ◽  
Author(s):  
Gregory A. Greene ◽  
Lori D. Daniels
Keyword(s):  
Fire Regimes ◽  
Spatial Modelling ◽  
Sensitivity Analyses ◽  
Tree Age ◽  
Fire Scars ◽  
Fire Scar ◽  
Distance Weighted ◽  
Mean Fire Interval ◽  
Fire Intervals ◽  
Inverse Distance

Tree-age data in combination with fire scars improved inverse-distance-weighted spatial modelling of historical fire boundaries and intervals for the Darkwoods, British Columbia, Canada. Fire-scarred trees provided direct evidence of fire. The presence of fire-sensitive trees at sites with no fire scars indicated fire-free periods over their lifespan. Sensitivity analyses showed: (1) tree ages used in combination with fire-scar dates refined fire boundaries without biasing mean fire return intervals; and (2) compared with derived conservative, moderate and liberal thresholds (i.e. minimum burn likelihood cut-off values), fixed thresholds generated area burned estimates that were most consistent with estimates based on the proportion of plots that recorded historical fires. Unweighted and weighted spatial mean fire intervals (50–56 and 58–68 years respectively) exceeded dendrochronological plot-level (38-year) estimates based on fire scars only. Including tree-age data from fire-sensitive trees to calculate landscape-level fire interval metrics lengthened the mean return intervals, better representing historical high-severity fires. Supplementing fire scars with tree ages better reflects the spatiotemporal diversity of fire frequencies and severities inherent to mixed-severity fire regimes.

Influence of landscape structure on patterns of forest fires in boreal forest landscapes in Sweden

2004 ◽  
Vol 34 (2) ◽  
pp. 332-338 ◽  
Author(s):  
Erik Hellberg ◽  
Mats Niklasson ◽  
Anders Granström
Keyword(s):  
Boreal Forest ◽  
Forest Fires ◽  
Landscape Structure ◽  
Fire Regime ◽  
Spatial And Temporal Patterns ◽  
Fire Scars ◽  
Maximal Interval ◽  
Landscape Types ◽  
Fire Intervals ◽  
Cross Dating

To analyze the effect of landscape structure (viz. amount of wetlands) on the past forest fire regime in boreal Sweden, we reconstructed detailed fire histories by cross-dating fire scars in living and dead Scots pine (Pinus sylvestris L.) in two different landscape types: mire-free landscapes with a low proportion (1%–2%) of mires and mire-rich landscapes with a high proportion (21%–33%) of mires. Two localities were selected and at each one, adjacent mire-free and mire-rich areas of 256–601 ha were sampled. Over the studied 650-year period, the two landscape types differed primarily in the fire intervals and sizes of fires. In the mire-rich landscapes, fires had frequently stopped against mire elements. The net effect was significantly longer fire intervals in the mire-rich than in the mire-free landscape (on average, 32 versus 56 years). The mire-rich areas also had a tail of very long fire intervals lacking in the mire-free areas (maximal interval 292 years). We conclude that mires can have a profound effect on both spatial and temporal patterns of forest fires in the boreal forest, but only when they are effective fuel breaks (i.e., they are wet enough) at the time the fires burn and if they truly dissect the nonmire portion of the forest landscape.

scholarly journals Dwarf Blackgum (Nyssa sylvatica) Contains Datable Fire Scars that Complement an Existing Fire History

Fire ◽  
2019 ◽  
Vol 2 (4) ◽  
pp. 61
Author(s):  
Thomas Saladyga
Keyword(s):  
Tree Species ◽  
Fire History ◽  
Fire Regime ◽  
Wide Distribution ◽  
Tree Age ◽  
Fire Scars ◽  
Fire Scar ◽  
Nyssa Sylvatica ◽  
Fire Intervals ◽  
In Fire

Blackgum (Nyssa sylvatica) is a “consummate subordinate” hardwood tree species consigned to the mid-canopy of many eastern North American forests. Despite its wide distribution and ecological amplitude, blackgum is an underutilized tree species in fire history reconstructions within its range. In this study, I analyzed cross-section samples collected from 19 fire-scarred blackgum trees at a dry, nutrient-poor ridgetop study area in northeastern Pennsylvania. All but two of these samples were successfully crossdated, each containing between one and six fire scars. Fires recorded by blackgum occurred frequently, with site-level mean fire intervals between approximately three and five years. There was an increase in blackgum growth within two years following fire events, but this increase was not statistically significant and it was dependent on local fire regime characteristics. In addition, the blackgum fire-scar data increased the temporal and spatial resolution of an existing local fire history. These results provide evidence for the potential use of blackgum in fire history reconstructions, but applications may be limited by tree age, complacent growth that prevents crossdating, and the degree of rot resistance after scarring.

scholarly journals Distinct patterns in the diurnal and seasonal variability in four components of soil respiration in a temperate forest under free-air CO<sub>2</sub> enrichment

2011 ◽  
Vol 8 (10) ◽  
pp. 3077-3092 ◽  
Author(s):  
L. Taneva ◽  
M. A. Gonzalez-Meler
Keyword(s):  
Soil Respiration ◽  
Seasonal Variability ◽  
Ecosystem Respiration ◽  
Co2 Efflux ◽  
Diurnal Variability ◽  
Soil C ◽  
Free Air ◽  
C Cycle ◽  
Strong Control ◽  
Average Contribution

Abstract. Soil respiration (RS) is a major flux in the global carbon (C) cycle. Responses of RS to changing environmental conditions may exert a strong control on the residence time of C in terrestrial ecosystems and in turn influence the atmospheric concentration of greenhouse gases. Soil respiration consists of several components oxidizing soil C from different pools, age and chemistry. The mechanisms underlying the temporal variability of RS components are poorly understood. In this study, we used the long-term whole-ecosystem 13C tracer at the Duke Forest Free Air CO2 Enrichment site to separate forest RS into its autotrophic (RR) and heterotrophic components (RH). The contribution of RH to RS was further partitioned into litter decomposition (RL), and decomposition of soil organic matter (RSOM) of two age classes – up to 8 yr old and SOM older than 8 yr. Soil respiration was generally dominated by RSOM during the growing season (44% of daytime RS), especially at night. The contribution of heterotrophic respiration (RSOM and RL) to RS was not constant, indicating that the seasonal variability in RR alone cannot explain seasonal variation in RS. Although there was no diurnal variability in RS, there were significant compensatory differences in the contribution of individual RS components to daytime and nighttime rates. The average contribution of RSOM to RS was greater at night (54%) than during the day (44%). The average contribution of RR to total RS was ~30% during the day and ~34% during the night. In contrast, RL constituted 26% of RS during the day and only 12% at night. About 95% of the decomposition of soil C older than 8 yr (Rpre-tr) originated from RSOM and showed more pronounced and consistent diurnal variability than any other RS component; nighttime rates were on average 29% higher than daytime rates. In contrast, the decomposition of more recent, post-treatment C (Rpre-tr) did not vary diurnally. None of the diurnal variations in components of RH could be explained by only temperature and moisture variations. Our results indicate that the variation observed in the components of RS is the result of complex interaction between dominant biotic controls (e.g. plant activity, mineralization kinetics, competition for substrates) over abiotic controls (temperature, moisture). The interactions and controls among roots and other soil organisms that utilize C of different chemistry, accessibility and ages, results in the overall soil CO2 efflux. Therefore understanding the controls on the components of RS is necessary to elucidate the influence of ecosystem respiration on atmospheric C-pools at different time scales.

Late-summer carbon fluxes from Canadian forests and peatlands along an east–west continental transect

2006 ◽  
Vol 36 (3) ◽  
pp. 783-800 ◽  
Author(s):  
Carole Coursolle ◽  
Hank A Margolis ◽  
Alan G Barr ◽  
T Andrew Black ◽  
Brian D Amiro ◽  
...  
Keyword(s):  
Large Scale ◽  
Ecosystem Respiration ◽  
Late Summer ◽  
Ecosystem Productivity ◽  
Diurnal Courses ◽  
Continental Scale ◽  
Young Forest ◽  
C Cycle ◽  
Use Efficiency ◽  
East West

Net ecosystem productivity (NEP) during August 2003 was measured by using eddy covariance above 17 forest and 3 peatland sites along an east–west continental-scale transect in Canada. Measured sites included recently disturbed stands, young forest stands, intermediate-aged conifer stands, mature deciduous stands, mature conifer stands, fens, and an open shrub bog. Diurnal courses of NEP showed strong coherence within the different ecosystem categories. Recently disturbed sites showed the weakest diurnal cycle; and intermediate-aged conifers, the strongest. The western treed fen had a more pronounced diurnal pattern than the eastern shrub bog or the Saskatchewan patterned fen. All but three sites were clearly afternoon C sinks. Ecosystem respiration was highest for the young fire sites. The intermediate-aged conifer sites had the highest maximum NEP (NEPmax) and gross ecosystem productivity (GEPmax), attaining rates that would be consistent with the presence of a strong terrestrial C sink in regions where these types of forest are common. These results support the idea that large-scale C cycle modeling activities would benefit from information on the age-class distribution and disturbance types within larger grid cells. Light use efficiency followed a pattern similar to that of NEPmax and GEPmax. Four of the five recently disturbed sites and all three of the peatland sites had low water use efficiencies.

scholarly journals Preliminary results of soil respiration in beech, spruce and grassy stands

2013 ◽  
Vol 59 (3) ◽  
Author(s):  
Tibor Priwitzer ◽  
Jozef Capuliak ◽  
Michal Bošela ◽  
Matej Schwarz
Keyword(s):  
Soil Respiration ◽  
Terrestrial Ecosystems ◽  
Forest Stands ◽  
Preliminary Results ◽  
Young Forest

AbstractSoil respiration constitutes the second largest flux of carbon between terrestrial ecosystems and the atmosphere. This study provides the preliminary results of soil respiration (Rs) observations in three different stands, including two types of young forest stands (beech and spruce) and grassy clearings. The average values of Rs ranged from 0.92 to 15.20 μmol CO

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