scholarly journals Timing of fire relative to seed development controls availability of non-serotinous aerial seed banks

2012 ◽  
Vol 9 (11) ◽  
pp. 16705-16751 ◽  
Author(s):  
S. T. Michaletz ◽  
E. A. Johnson ◽  
W. E. Mell ◽  
D. F. Greene
Keyword(s):  
Seed Development ◽  
Picea Glauca ◽  
White Spruce ◽  
Fire Regimes ◽  
Seed Banks ◽  
Conduction Model ◽  
Area Burned ◽  
Spread Model ◽  
In Fire ◽  
Germinable Seed

Abstract. The existence of non-serotinous, non-sprouting species in fire regimes where serotiny confers an adaptive advantage is puzzling, particularly when these species recruit poorly from soil seed banks or from burn edges. In this paper, white spruce (Picea glauca (Moench) Voss) was used to show that the timing of fire relative to seed development can control aerial seed bank availability for non-serotinous species. To estimate seed survival in closed cones during crown fires, cone heating was simulated using a one-dimensional conduction model implemented in a computational fluid dynamics (Navier–Stokes) fire spread model. To quantify the area burned when germinable seed would be contained in closed cones, empirical fire occurrence and seed development (germinability and cone opening) data were compared for multiple locations across the white spruce range. Approximately 12% of cones contained viable seed following crown fire simulations (0.072 m s−1 mean spread rate; 9147 kW m−1 mean intensity), and roughly half of the historical area burned resulted from fires that occurred when closed cones would contain germinable seed. Post-fire recruitment from in situ aerial seed banks can occur for non-serotinous species, and may be an important cause of their existence in fire regimes to which they otherwise seem poorly suited.

scholarly journals Timing of fire relative to seed development may enable non-serotinous species to recolonize from the aerial seed banks of fire-killed trees

2013 ◽  
Vol 10 (7) ◽  
pp. 5061-5078 ◽  
Author(s):  
S. T. Michaletz ◽  
E. A. Johnson ◽  
W. E. Mell ◽  
D. F. Greene
Keyword(s):  
Seed Development ◽  
Fire Behavior ◽  
White Spruce ◽  
Fire Regimes ◽  
Seed Banks ◽  
Conduction Model ◽  
Burned Areas ◽  
Area Burned ◽  
In Fire ◽  
Germinable Seed

Abstract. The existence of non-serotinous, non-sprouting species in fire regimes where serotiny confers an adaptive advantage is puzzling, particularly when these species recruit poorly from soil seed banks or from burn edges. In this paper, white spruce (Picea glauca (Moench) Voss) was used to show how the timing of fire relative to seed development may permit non-serotinous species to recolonize burned areas from the aerial seed banks of fire-killed trees. To estimate survival of seeds within closed cones during crown fires, cone heating was simulated using a one-dimensional conduction model implemented in a three-dimensional computational fluid dynamics fire behavior model. To quantify the area burned when germinable seed would be contained within closed cones during a mast year, empirical fire occurrence and seed development (germinability and cone opening) data were compared for multiple locations across the white spruce range. Approximately 12% of cones contained viable seed following crown fire simulations (0.072 m s−1 mean spread rate; 9147 kW m−1 mean intensity), and roughly half of the historical area burned resulted from fires that occurred when closed cones would contain germinable seed. Together, these results suggest that non-serotinous species may recolonize burned areas from in situ aerial seed banks, and that this may be an important cause of their existence in fire regimes to which they otherwise seem poorly suited.

Parental environment aftereffects on germination, growth, and adaptive traits in selected white spruce families

1998 ◽  
Vol 28 (3) ◽  
pp. 418-426 ◽  
Author(s):  
Michael U Stoehr ◽  
Sylvia J L'Hirondelle ◽  
Wolfgang D Binder ◽  
Joe E Webber
Keyword(s):  
British Columbia ◽  
Seed Development ◽  
Picea Glauca ◽  
White Spruce ◽  
Seed Orchard ◽  
Field Season ◽  
Germination Traits ◽  
Reproductive Processes ◽  
Progeny Performance ◽  
Needle Primordia

Seed orchards for the production of conifer seed in British Columbia are usually located in areas favorable (warm and dry) for flowering and seed development, often considerably south of the source location of the parent trees. Differences in environmental conditions between seed orchard location and location of origin can affect progeny performance. It is suspected that this is caused by environmental factors that affect reproductive processes of parent trees and lead to altered physiological traits (aftereffects). This study examined if aftereffects are present in white spruce (Picea glauca (Moench) Voss). Control pollinations were made at two locations, Red Rock, near Prince George (53°N) in central British Columbia, and Kalamalka, near Vernon (50°N) in southern British Columbia, on five female trees using a four-male polymix. Identical genotypes through grafting were present at the two locations. Pollen maturing at each site was only used in the polymix at that particular location. Progeny were raised and germination traits, number of needle primordia, greenhouse and field heights, and frost hardiness were evaluated in a common environment. The location of seed development significantly affected all traits evaluated. Height growth aftereffects in the second field season were much less than those observed in the first field season. These results suggest that aftereffects are detectable in white spruce progeny performance in British Columbia.

scholarly journals Modelling long-term fire regimes of southern California shrublands

2011 ◽  
Vol 20 (1) ◽  
pp. 1 ◽  
Author(s):  
Seth H. Peterson ◽  
Max A. Moritz ◽  
Marco E. Morais ◽  
Philip E. Dennison ◽  
Jean M. Carlson
Keyword(s):  
Southern California ◽  
Fire Regime ◽  
Fire Regimes ◽  
Fire Spread ◽  
Computationally Efficient ◽  
Interval Maps ◽  
Spread Model ◽  
Wind Events ◽  
In Fire

This paper explores the environmental factors that drive the southern California chaparral fire regime. Specifically, we examined the response of three fire regime metrics (fire size distributions, fire return interval maps, cumulative total area burned) to variations in the number of ignitions, the spatial pattern of ignitions, the number of Santa Ana wind events, and live fuel moisture, using the HFire fire spread model. HFire is computationally efficient and capable of simulating the spatiotemporal progression of individual fires on a landscape and aggregating results for fully resolved individual fires over hundreds or thousands of years to predict long-term fire regimes. A quantitative understanding of the long-term drivers of a fire regime is of use in fire management and policy.

Potentially limited detectability of short-term changes in boreal fire regimes: a simulation study

2010 ◽  
Vol 19 (8) ◽  
pp. 1140 ◽  
Author(s):  
Juha M. Metsaranta
Keyword(s):  
Sustainable Forest Management ◽  
Null Model ◽  
Fire Regimes ◽  
Late 20Th Century ◽  
Fire Cycle ◽  
Early 21St Century ◽  
Boreal Plains ◽  
Area Burned ◽  
Wide Range ◽  
In Fire

Climate change is expected to increase area burned in the boreal plains ecozone of Canada in the early 21st century (2001–50). I examined the influence of inter-annual variability in area burned and short observed time series on the probability of detecting if an increase has occurred, using a null model of present and future fire regimes. A wide range of fire cycles are consistent with annual area burned in the late 20th century (1959–99). Fire cycles estimated from the reciprocal of the average annual burn fraction over a 50-year period are not very precise, and overestimate the fire cycle if years with large annual area burned have not recently occurred. Under the default assumptions, the probability of detecting a doubling of annual area burned during 2001–50 is 73% if it occurred instantaneously, but only 31% if it occurred gradually. Imprecise estimates and uncertainty in the ability to detect changes in fire cycles poses challenges for implementing aspects of sustainable forest management. Alternate empirical or model-based statistics, such as return periods for annual areas burned of a given magnitude, may be useful for inferring frequencies and magnitudes of large fire years that have not yet been observed.

Fire-regime changes in Canada over the last half century

2019 ◽  
Vol 49 (3) ◽  
pp. 256-269 ◽  
Author(s):  
Chelene C. Hanes ◽  
Xianli Wang ◽  
Piyush Jain ◽  
Marc-André Parisien ◽  
John M. Little ◽  
...  
Keyword(s):  
Fire Regime ◽  
Fire Regimes ◽  
Fire Season ◽  
Western Canada ◽  
Half Century ◽  
Regime Changes ◽  
Area Burned ◽  
Active Fire ◽  
Large Fires ◽  
In Fire

Contemporary fire regimes of Canadian forests have been well documented based on forest fire records between the late 1950s to 1990s. Due to known limitations of fire datasets, an analysis of changes in fire-regime characteristics could not be easily undertaken. This paper presents fire-regime trends nationally and within two zonation systems, the homogeneous fire-regime zones and ecozones, for two time periods, 1959–2015 and 1980–2015. Nationally, trends in both area burned and number of large fires (≥200 ha) have increased significantly since 1959, which might be due to increases in lightning-caused fires. Human-caused fires, in contrast, have shown a decline. Results suggest that large fires have been getting larger over the last 57 years and that the fire season has been starting approximately one week earlier and ending one week later. At the regional level, trends in fire regimes are variable across the country, with fewer significant trends. Area burned, number of large fires, and lightning-caused fires are increasing in most of western Canada, whereas human-caused fires are either stable or declining throughout the country. Overall, Canadian forests appear to have been engaged in a trajectory towards more active fire regimes over the last half century.

Pathways for climate change effects on fire: Models, data, and uncertainties

2011 ◽  
Vol 35 (3) ◽  
pp. 393-407 ◽  
Author(s):  
Amy E. Hessl
Keyword(s):  
Climate Change ◽  
Fire History ◽  
Wildland Fire ◽  
Fire Severity ◽  
Empirical Studies ◽  
Large Body ◽  
Fire Regimes ◽  
Area Burned ◽  
Frequency Changes ◽  
In Fire

Fire is a global process affecting both the biosphere and the atmosphere. As a result, measuring rates of change in wildland fire and understanding the mechanisms responsible for such changes are important research goals. A large body of modeling studies projects increases in wildfire activity in future decades, but few empirical studies have documented change in modern fire regimes. Identifying generalizable pathways through which climate change may alter fire regimes is a critical next step for understanding, measuring, and modeling fire under a changing climate. In this progress report, I review recent model-, empirical-, and fire history-based studies of fire and climate change and propose three pathways along which fire regimes might respond to climate change: changes in fuel condition, fuel volume, and ignitions. Model- and empirical-based studies have largely focused on changes in fuel condition with some models projecting up to 50% increases in area burned under a 2 x CO2 climate. Fire history data derived from tree-rings, sediment charcoal, and soil charcoal have helped identify past trajectories of change in fire regimes and can point to possible future conditions. However, most fire history research has focused on changes in area burned and fire frequency. Changes in fire severity may be equally important for the earth system and require further attention. Critical research needs include next generation dynamic vegetation models (DGVMs) that consider changes in vegetation alongside changes in human activities and long fire history records from a variety of vegetation types suitable for validating these DGVMs.

scholarly journals Classification of Post-Fire Responses of Woody Plants to include Pyrophobic Communities

Fire ◽  
2020 ◽  
Vol 3 (2) ◽  
pp. 15 ◽  
Author(s):  
Lynda D. Prior ◽  
David M. J. S. Bowman
Keyword(s):  
Woody Plants ◽  
Seed Banks ◽  
Classification Systems ◽  
Woody Vegetation ◽  
General Category ◽  
Conifer Species ◽  
Soil Seed Banks ◽  
Obligate Seeder ◽  
In Fire

Developing standardised classification of post-fire responses is essential for globally consistent comparisons of woody vegetation communities. Existing classification systems are based on responses of species growing in fire-prone environments. To accommodate species that occur in rarely burnt environments, we have suggested some important points of clarification to earlier schemes categorizing post-fire responses. We have illustrated this approach using several Australasian conifer species as examples of pyrophobic species. In particular, we suggest using the term “obligate seeder” for the general category of plants that rely on seed to reproduce, and qualifying this to “post-fire obligate seeder” for the narrower category of species with populations that recover from canopy fire only by seeding; the species are typically fire-cued, with large aerial or soil seed banks that germinate profusely following a fire, and grow and reproduce rapidly in order to renew the seed bank before the next fire.

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