Quantifying Fire Cycle from Dendroecological Records Using Survival Analyses

Cyr, Dominic; Gauthier, Sylvie; Boulanger, Yan; Bergeron, Yves

doi:10.3390/f7070131

Cited by 15 publications

(26 citation statements)

References 53 publications

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“…Furthermore, our study is one of the first that analyzes the fire regime from empirical data in the area covered by the northern zones of transects C and D, thus making it difficult to compare our results with others. However, we assume our fire cycle estimates are realistic based on the overall consistency between our results and those of other studies as well as the reliability of the estimates produced by the Cox analyses [37].…”

Section: Fire Cyclementioning

confidence: 55%

“…This is a major advantage compared to regular fire cycle analyses, which strictly assume that TSF is given by the stand age, with no distinction in stands that have been attributed a minimum age. This often leads to an underestimation of the fire cycle that can be attenuated with survival analyses [37].…”

Section: Statistical Analysesmentioning

confidence: 99%

“…In terms of fire history, it means that since the model does not assume a constant risk of burning through time, it allows for variations in the fire regime that could have happened in the past, resulting, for example, from human activities or climate change. Those variations are therefore taken into account while calculating the fire cycle, giving a more precise fire history estimate [37]. The second part of the Cox model is parametric and is estimated using the method of partial likelihood [38].…”

Section: Statistical Analysesmentioning

confidence: 99%

“…The estimated cumulative hazard of burning (baseline hazard function) could then be extracted for each transect zone [41], representing the accumulated hazard of burning through time. The time it takes for the cumulative hazard to reach 1 is equivalent to the fire cycle [37,39]. To estimate the fire cycle, the time at which the cumulative hazard reached or exceeded 1 was then divided by its associated cumulative hazard.…”

Section: Fire Cyclementioning

confidence: 99%

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Fire Regime along Latitudinal Gradients of Continuous to Discontinuous Coniferous Boreal Forests in Eastern Canada

Portier

Gauthier

Leduc

et al. 2016

Forests

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Abstract:Fire is the main disturbance in North American coniferous boreal forests. In Northern Quebec, Canada, where forest management is not allowed, the landscape is gradually constituted of more opened lichen woodlands. Those forests are discontinuous and show a low regeneration potential resulting from the cumulative effects of harsh climatic conditions and very short fire intervals. In a climate change context, and because the forest industry is interested in opening new territories to forest management in the north, it is crucial to better understand how and why fire risk varies from the north to the south at the transition between the discontinuous and continuous boreal forest. We used time-since-fire (TSF) data from fire archives as well as a broad field campaign in Quebec's coniferous boreal forests along four north-south transects in order to reconstruct the fire history of the past 150 to 300 years. We performed survival analyses in each transect in order to (1) determine if climate influences the fire risk along the latitudinal gradient; (2) fractionate the transects into different fire risk zones; and (3) quantify the fire cycle-defined as the time required to burn an area equivalent to the size of the study area-of each zone and compare its estimated value with current fire activity. Results suggest that drought conditions are moderately to highly responsible for the increasing fire risk from south to north in the three westernmost transects. No climate influence was observed in the last one, possibly because of its complex physical environment. Fire cycles are shortening from south to north, and from east to west. Limits between high and low fire risk zones are consistent with the limit between discontinuous and continuous forests, established based on recent fire activity. Compared to the last 40 years, fire cycles of the last 150-300 years are shorter. Our results suggest that as drought episodes are expected to become more frequent in the future, fire activity might increase significantly, possibly leading to greater openings within forests. However, if fire activity increases and yet remains within the range of variability of the last 150-300 years, the limit between open and closed forests should stay relatively stable.

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Section: Fire Cyclementioning

confidence: 55%

Section: Statistical Analysesmentioning

confidence: 99%

Section: Statistical Analysesmentioning

confidence: 99%

Section: Fire Cyclementioning

confidence: 99%

See 2 more Smart Citations

Fire Regime along Latitudinal Gradients of Continuous to Discontinuous Coniferous Boreal Forests in Eastern Canada

Portier

Gauthier

Leduc

et al. 2016

Forests

Self Cite

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“…Independently reconstructed forest age structures at the landscape scale have previously been used to evaluate fire activity changes in Eastern North America, following the termination of the Little Ice Age (LIA) (Bergeron & Archambault, 1993;Bergeron et al, 2001;Girardin et al, 2013). The stand initiation map represents an outcome of dendrochronological dating of cohort establishment dates over an area considerably exceeding the size of single disturbance events (> 10 3-4 ha and above) (Cyr et al, 2016;van Wagner, 1978). The resulting stand age distribution can be viewed as a distribution of time passed since the last stand Figure 1a, black lines delimit the areas analyzed for changes in fire cycles (supporting information Table S1).…”

Section: Analysis Of Stand Initiation Mapsmentioning

confidence: 99%

Strong Gradients in Forest Sensitivity to Climate Change Revealed by Dynamics of Forest Fire Cycles in the Post Little Ice Age Era

et al. 2017

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The length of the fire cycle is a critical factor affecting the vegetation cover in boreal and temperate regions. However, its responses to climate change remain poorly understood. We reanalyzed data from earlier studies of forest age structures at the landscape level, in order to map the evolution of regional fire cycles across Eastern North American boreal and temperate forests, following the termination of the Little Ice Age (LIA). We demonstrated a well‐defined spatial pattern of post‐LIA changes in the length of fire cycles toward lower fire activity during the 1800s and 1900s. The western section of Eastern North America (west of 77°W) experienced a decline in fire activity as early as the first half of the 1800s. By contrast, the eastern section showed these declines as late as the early 1900s. During a regionally fire‐prone period of the 1910s–1920s, forests in the western section of Eastern boreal North America burned more than forests in the eastern section. The climate appeared to dominate over vegetation composition and human impacts in shaping the geographical pattern of the post‐LIA change in fire activity. Changes in the atmospheric circulation patterns following the termination of the LIA, specifically changes in Arctic Oscillation and the strengthening of the Continental Polar Trough, were likely drivers of the regional fire dynamics.

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Landscape‐scale patterns of eastern spruce budworm outbreak risk: Defoliation onset vs. tree mortality

McNie,

Kneeshaw,

Filotas

2023

Ecosphere

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The stand‐level risk of both defoliation and mortality due to the spruce budworm (Choristoneura fumiferana, Clem., SBW) is mainly linked to the quality of the resource such that stands dominated by the primary host species, balsam fir (Abies balsamea [L.] Mill.), are considered the most vulnerable. At the landscape scale, insect dispersal suggests that both configuration and resource availability should influence the onset and subsequent mortality of an outbreak. However, outbreak risk at this scale is yet to be quantified for the SBW, one of the most studied forest pest defoliators in the world. We aim to determine the risk of both SBW defoliation onset and resultant tree mortality at a landscape scale due to factors that have been associated with SBW defoliation at the stand scale. We used Cox proportional hazard models to quantify the relative risk of different landscape configuration and species composition patterns on defoliation onset and risk of mortality of the current SBW outbreak in Eastern Canada. In particular, we measured the risk associated with primary host proportion, relative amounts of secondary host and hardwood trees to fir trees, the structure of balsam fir in the landscape, and the structure of the forest overall. We show that defoliation onset is more related to the configuration of the landscape than to the species composition while the risk of ensuing mortality increases as the proportion of the primary host increases. Defoliation onset risk is increased by a more complex configuration of fir patches in the landscape. Mortality risk, however, is unaffected by fir configuration but is reduced where there is more black spruce (Picea mariana [Mill.] B.S.P.) or a decrease of balsam fir in the landscape. The usefulness of survival analysis for assessing risk for insect outbreaks has been overlooked and can quantify the effect of relevant factors to guide management and mitigation strategies. The results of our analysis suggest that forest management strategies should avoid clear cuts and the development of fir monocultures and instead maintain or increase the proportion of black spruce and improve forest connectivity across large forested landscapes to delay defoliation onset and reduce SBW‐related mortality.

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Quantifying Fire Cycle from Dendroecological Records Using Survival Analyses

Cited by 15 publications

References 53 publications

Fire Regime along Latitudinal Gradients of Continuous to Discontinuous Coniferous Boreal Forests in Eastern Canada

Fire Regime along Latitudinal Gradients of Continuous to Discontinuous Coniferous Boreal Forests in Eastern Canada

Strong Gradients in Forest Sensitivity to Climate Change Revealed by Dynamics of Forest Fire Cycles in the Post Little Ice Age Era

Landscape‐scale patterns of eastern spruce budworm outbreak risk: Defoliation onset vs. tree mortality

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