Long-term reconstruction of the fire season in the mixedwood boreal forest of Western Canada

1999 ◽  
Vol 77 (8) ◽  
pp. 1185-1188 ◽  
Author(s):  
E A Johnson ◽  
K Miyanishi ◽  
N O'Brien
Keyword(s):  
Boreal Forest ◽  
Pinus Banksiana ◽  
Fire Frequency ◽  
Fire Season ◽  
Climate Modelling ◽  
Fire Scars ◽  
Fire Cycle ◽  
Modelling Studies ◽  
Prince Albert National Park ◽  
In Fire

Climate modelling studies have predicted an increase in fire frequency with global warming as well as suggesting a longer fire season occurring later in the year. We used 160 years of fire scars in Pinus banksiana Lamb. dating from 1831 to 1948 and written fire records from 1927 to 1995 for Prince Albert National Park in the southern boreal forest to look for evidence of changes in the duration and timing of the fire season (defined as the months when large areas burn) that may have accompanied past changes in fire frequency. The Park's time-since-fire distribution had indicated two such changes: one around 1890 and the other around 1945, both in the direction of decreasing fire frequency. Both fire scars and written fire records indicated that the dominance of the spring fire season (April-June) has remained unchanged over the past 160 years. A small number of scars suggested that the fire season may have extended slightly into the summer (July) prior to 1890 when the fire cycle was much shorter and that the fire season may have shifted to a slightly earlier spring start after 1945 when the fire cycle was much longer.Key words: fire season, boreal forest, fire frequency.

Natural fire frequency for the eastern Canadian boreal forest: consequences for sustainable forestry

2001 ◽  
Vol 31 (3) ◽  
pp. 384-391 ◽  
Author(s):  
Yves Bergeron ◽  
Sylvie Gauthier ◽  
Victor Kafka ◽  
Patrick Lefort ◽  
Daniel Lesieur
Keyword(s):  
Boreal Forest ◽  
Forest Fires ◽  
Sustainable Forest Management ◽  
Fire Frequency ◽  
Ice Age ◽  
Eastern Canada ◽  
Entire Area ◽  
Fire Cycle ◽  
Clear Cutting ◽  
In Fire

Given that fire is the most important disturbance of the boreal forest, climatically induced changes in fire frequency (i.e., area burnt per year) can have important consequences on the resulting forest mosaic age-class distribution and composition. Using archives and dendroecological data we reconstructed the fire frequency in four large sectors along a transect from eastern Ontario to central Quebec. Results showed a dramatic decrease in fire frequency that began in the mid-19th century and has been accentuated during the 20th century. Although all areas showed a similar temporal decrease in area burned, we observed a gradual increase in fire frequency from the west to Abitibi east, followed by a slight decrease in central Quebec. The global warming that has been occurring since the end of the Little Ice Age (~1850) may have created a climate less prone to large forest fires in the eastern boreal forest of North America. This interpretation is corroborated by predictions of a decrease in forest fires for that region of the boreal forest in the future. A longer fire cycle (i.e., the time needed to burn an area equivalent to the study area) has important consequences for sustainable forest management of the boreal forest of eastern Canada. When considering the important proportion of overmature and old-growth stands in the landscape resulting from the elongation of the fire cycles, it becomes difficult to justify clear-cutting practices over all the entire area as well as short rotations as a means to emulate natural disturbances. Alternative practices involving the uses of variable proportion of clear, partial, and selective cutting are discussed.

Comment—A re-examination of the effects of fire suppression in the boreal forest

2001 ◽  
Vol 31 (8) ◽  
pp. 1462-1466 ◽  
Author(s):  
K Miyanishi ◽  
E A Johnson
Keyword(s):  
Boreal Forest ◽  
Fire Management ◽  
Fire Suppression ◽  
Fire Frequency ◽  
Stand Age ◽  
Reliable Estimate ◽  
Fire Size ◽  
Fire Cycle ◽  
Large Fires ◽  
In Fire

A report by Ward and Tithecott (P.C. Ward and A.G. Tithecott. 1993. Ontario Ministry of Natural Resources, Aviation, Flood and Fire Management Branch, Publ. 305.) is frequently cited in the literature as providing evidence of the effects of fire suppression on the boreal forest. The study is based on 15 years of fire data and stand age data from Ontario, Canada. A re-examination of this report reveals serious flaws that invalidate the conclusions regarding effects of fire suppression on fire size and fire frequency. The fire-size data from the unprotected zone are censored in the small size classes because of detection resolution, invalidating comparisons of shapes of the distributions between the protected and unprotected zones. Use of different plotting scales gives the false appearance of large differences in the number of large fires between the two zones. Stand age data are used to show a change in fire frequency in the 20th century, and this change is attributed to fire suppression. However, no evidence is presented to conclude that this change in fire frequency is attributable to fire suppression and not to climate change. The estimate of the current fire cycle is based on too short a record to give a reliable estimate given the variation in annual area burned. Therefore, this report does not present sound evidence of fire suppression effects and should not be cited as such.

scholarly journals Resilience of the boreal forest in response to Holocene fire-frequency changes assessed by pollen diversity and population dynamics

2010 ◽  
Vol 19 (8) ◽  
pp. 1026 ◽  
Author(s):  
Christopher Carcaillet ◽  
Pierre J. H. Richard ◽  
Yves Bergeron ◽  
Bianca Fréchette ◽  
Adam A. Ali
Keyword(s):  
Boreal Forest ◽  
Boreal Forests ◽  
Frequency Control ◽  
Regional Scale ◽  
Fire Regimes ◽  
Fire Frequency ◽  
Frequency Changes ◽  
Fire Intervals ◽  
In Fire

The hypothesis that changes in fire frequency control the long-term dynamics of boreal forests is tested on the basis of paleodata. Sites with different wildfire histories at the regional scale should exhibit different vegetation trajectories. Mean fire intervals and vegetation reconstructions are based respectively on sedimentary charcoal and pollen from two small lakes, one in the Mixedwood boreal forests and the second in the Coniferous boreal forests. The pollen-inferred vegetation exhibits different trajectories of boreal forest dynamics after afforestation, whereas mean fire intervals have no significant or a delayed impact on the pollen data, either in terms of diversity or trajectories. These boreal forests appear resilient to changes in fire regimes, although subtle modifications can be highlighted. Vegetation compositions have converged during the last 1200 years with the decrease in mean fire intervals, owing to an increasing abundance of boreal species at the southern site (Mixedwood), whereas changes are less pronounced at the northern site (Coniferous). Although wildfire is a natural property of boreal ecosystems, this study does not support the hypothesis that changes in mean fire intervals are the key process controlling long-term vegetation transformation. Fluctuations in mean fire intervals alone do not explain the historical and current distribution of vegetation, but they may have accelerated the climatic process of borealisation, likely resulting from orbital forcing.

scholarly journals The pyrogeography of eastern boreal Canada from 1901 to 2012 simulated with the LPJ-LMfire model

2018 ◽  
Vol 15 (5) ◽  
pp. 1273-1292 ◽  
Author(s):  
Emeline Chaste ◽  
Martin P. Girardin ◽  
Jed O. Kaplan ◽  
Jeanne Portier ◽  
Yves Bergeron ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Net Primary Productivity ◽  
General Pattern ◽  
Fire Frequency ◽  
Spatiotemporal Patterns ◽  
Eastern Canada ◽  
Time Step ◽  
Dynamic Global Vegetation Model ◽  
Fire Activity ◽  
In Fire

Abstract. Wildland fires are the main natural disturbance shaping forest structure and composition in eastern boreal Canada. On average, more than 700 000 ha of forest burns annually and causes as much as CAD 2.9 million worth of damage. Although we know that occurrence of fires depends upon the coincidence of favourable conditions for fire ignition, propagation, and fuel availability, the interplay between these three drivers in shaping spatiotemporal patterns of fires in eastern Canada remains to be evaluated. The goal of this study was to reconstruct the spatiotemporal patterns of fire activity during the last century in eastern Canada's boreal forest as a function of changes in lightning ignition, climate, and vegetation. We addressed this objective using the dynamic global vegetation model LPJ-LMfire, which we parametrized for four plant functional types (PFTs) that correspond to the prevalent tree genera in eastern boreal Canada (Picea, Abies, Pinus, Populus). LPJ-LMfire was run with a monthly time step from 1901 to 2012 on a 10 km2 resolution grid covering the boreal forest from Manitoba to Newfoundland. Outputs of LPJ-LMfire were analyzed in terms of fire frequency, net primary productivity (NPP), and aboveground biomass. The predictive skills of LPJ-LMfire were examined by comparing our simulations of annual burn rates and biomass with independent data sets. The simulation adequately reproduced the latitudinal gradient in fire frequency in Manitoba and the longitudinal gradient from Manitoba towards southern Ontario, as well as the temporal patterns present in independent fire histories. However, the simulation led to the underestimation and overestimation of fire frequency at both the northern and southern limits of the boreal forest in Québec. The general pattern of simulated total tree biomass also agreed well with observations, with the notable exception of overestimated biomass at the northern treeline, mainly for PFT Picea. In these northern areas, the predictive ability of LPJ-LMfire is likely being affected by the low density of weather stations, which leads to underestimation of the strength of fire–weather interactions and, therefore, vegetation consumption during extreme fire years. Agreement between the spatiotemporal patterns of fire frequency and the observed data across a vast portion of the study area confirmed that fire therein is strongly ignition limited. A drier climate coupled with an increase in lightning frequency during the second half of the 20th century notably led to an increase in fire activity. Finally, our simulations highlighted the importance of both climate and fire in vegetation: despite an overarching CO2-induced enhancement of NPP in LPJ-LMfire, forest biomass was relatively stable because of the compensatory effects of increasing fire activity.

scholarly journals Variability in Fire Frequency and Forest Composition in Canada's Southeastern Boreal Forest: A Challenge for Sustainable Forest Management

1998 ◽  
Vol 2 (2) ◽  
Author(s):  
Yves Bergeron ◽  
Pierre J.H. Richard ◽  
Christopher Carcaillet ◽  
Sylvie Gauthier ◽  
Mike Flannigan ◽  
...  
Keyword(s):  
Forest Management ◽  
Boreal Forest ◽  
Sustainable Forest Management ◽  
Fire Frequency ◽  
Forest Composition ◽  
In Fire

Fire return intervals within the northern boundary of the larch forest in Central Siberia

2013 ◽  
Vol 22 (2) ◽  
pp. 207 ◽  
Author(s):  
Vyacheslav I. Kharuk ◽  
Mariya L. Dvinskaya ◽  
K. Jon Ranson
Keyword(s):  
Little Ice Age ◽  
Fire History ◽  
Fire Frequency ◽  
Ice Age ◽  
The Arctic ◽  
Fire Scars ◽  
Lightning Strikes ◽  
Larch Forests ◽  
History Of ◽  
In Fire

A fire history of northern larch forests was studied. These larch forests are found near the northern limit of their range at ~71°N, where fires are predominantly caused by lightning strikes rather than human activity. Fire-return intervals (FRIs) were calculated based on fire scars and dates of tree natality. Tree natality was used as an approximation of the date of the last fire. The average FRI was found to be 295±57 years, which is the longest reported for larch-dominated stands. Prior studies reported 80–90-year FRIs at 64°N and ~200 years near the latitude of the Arctic Circle. Comparing data from fires that occurred in 1700–1849 (end of the Little Ice Age, LIA) and 1850–1999 (post-LIA warming) indicates approximately twice as many fires occurred during the latter period. This agrees with the hypothesis that observed climatic warming will result in an increase in fire frequency. Our results also indicate that fires that did not leave visible fire scars on the tree stem may be identified based on the date of growth release revealed from dendrochronology.

scholarly journals Century-Scale Fire Dynamics in a Savanna Ecosystem

Fire ◽  
2019 ◽  
Vol 2 (3) ◽  
pp. 51 ◽  
Author(s):  
Leys ◽  
Griffin ◽  
Larson ◽  
McLauchlan
Keyword(s):  
Tree Ring ◽  
Fire Regime ◽  
Fire Regimes ◽  
Landscape Fragmentation ◽  
Fire Frequency ◽  
Relative Role ◽  
Fire Dynamics ◽  
Fire Scars ◽  
Tree Ring Reconstruction ◽  
In Fire

(1) Background: Frequent fire, climate variability, and human activities collectively influence savanna ecosystems. The relative role of these three factors likely varies on interannual, decadal, and centennial timescales. Here, we tested if Euro-American activities uncoupled drought and fire frequencies relative to previous centuries in a temperate savanna site. (2) Methods: We combined records of fire frequency from tree ring fire scars and sediment charcoal abundance, and a record of fuel type based on charcoal particle morphometry to reconstruct centennial scale shifts in fire frequency and fuel sources in a savanna ecosystem. We also tested the climate influence on fire occurrence with an independently derived tree-ring reconstruction of drought. We contextualized these data with historical records of human activity. (3) Results: Tree fire scars revealed eight fire events from 1822–1924 CE, followed by localized suppression. Charcoal signals highlight 13 fire episodes from 1696–2001. Fire–climate coupling was not clearly evident both before and after Euro American settlement The dominant fuel source shifted from herbaceous to woody fuel during the early-mid 20th century. (4) Conclusions: Euro-American settlement and landscape fragmentation disrupted the pre-settlement fire regime (fire frequency and fuel sources). Our results highlight the potential for improved insight by synthesizing interpretation of multiple paleofire proxies, especially in fire regimes with mixed fuel sources.

Mixed-severity fire regimes: How well are they represented by existing fire-regime classification systems?

2013 ◽  
Vol 43 (7) ◽  
pp. 658-668 ◽  
Author(s):  
Hélène M. Marcoux ◽  
Sarah E. Gergel ◽  
Lori D. Daniels
Keyword(s):  
Field Data ◽  
Sustainable Forest Management ◽  
Fire Regime ◽  
Natural Disturbance ◽  
Fire Regimes ◽  
Fire Frequency ◽  
Classification Systems ◽  
Fire Scars ◽  
Natural Fire ◽  
In Fire

Maps depicting historic fire regimes provide critical baselines for sustainable forest management and wildfire risk assessments. However, given our poor understanding of mixed-severity fire regimes, we asked if there may be considerable errors in fire-regime classification systems used to create landscape-level maps. We used dendrochronological field data (fire scars and tree establishment dates) from 20 randomly selected sites in southern British Columbia to evaluate two classification systems (Natural Disturbance Type (NDT) and Historical Natural Fire Regime (HNFR)) used by managers to map fire regimes. We found evidence of mixed-severity fires at 55% of sites. Each classification system made considerable and contrasting errors predicting mixed-severity regimes (relative to field data), and the discrepancies varied with elevation. The NDT system underrepresented low-to-moderate-severity fires at lower elevations, whereas the HNFR system overpredicted their occurrence at higher elevations. Errors are attributed to underlying assumptions about disturbances in the two classification systems, as well as limitations of the research methods used to estimate fire frequency in mixed-severity regimes (i.e., methods more relevant to high- versus low-severity regimes). Ecological heterogeneity created by mixed-severity regimes potentially influences decisions related to conservation, silviculture, wildfire, and fuel mitigation. Thus, understanding underlying assumptions and errors in mapping fire regimes is critical.

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