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

摘要

The existence of non-serotinous, non-sprouting species in fire regimes whereserotiny confers an adaptive advantage is puzzling, particularly when thesespecies recruit poorly from soil seed banks or from burn edges. In thispaper, white spruce (Picea glauca (Moench) Voss) was used to showhow the timing of fire relative to seed development may permit non-serotinousspecies to recolonize burned areas from the aerial seed banks of fire-killedtrees. To estimate survival of seeds within closed cones during crown fires,cone heating was simulated using a one-dimensional conduction modelimplemented in a three-dimensional computational fluid dynamics fire behaviormodel. To quantify the area burned when germinable seed would be containedwithin closed cones during a mast year, empirical fire occurrence and seeddevelopment (germinability and cone opening) data were compared for multiplelocations across the white spruce range. Approximately 12% of conescontained viable seed following crown fire simulations (0.072 m s?1mean spread rate; 9147 kW m?1 mean intensity), and roughly half of thehistorical area burned resulted from fires that occurred when closed coneswould contain germinable seed. Together, these results suggest thatnon-serotinous species may recolonize burned areas from in situ aerial seedbanks, and that this may be an important cause of their existence in fireregimes to which they otherwise seem poorly suited.