Influence of fire refugia spatial pattern on post-fire forest recovery in Oregon's Blue Mountains
Authors:Downing, William M.Krawchuk, Meg A.Meigs, Garrett W.Haire, Sandra L.Coop, Jonathan D.Walker, Ryan B.Whitman, EllenChong, GenevaMiller, Carol
Source:LANDSCAPE ECOLOGY
Volume:34
DOI:10.1007/s10980-019-00802-1
Published:2019
Document Type:Article
Abstract:ContextFire regimes in many dry forests of western North America are substantially different from historical conditions, and there is concern about the ability of these forests to recover following severe wildfire. Fire refugia, unburned or low-severity burned patches where trees survived fire, may serve as essential propagule sources that enable forest regeneration.ObjectivesTo quantify the influence of fire refugia spatial pattern and other biophysical factors on the process of post-fire tree regeneration; in particular examining both the proximity and density of surrounding refugia to characterize the landscape of refugial seed sources.MethodsWe surveyed regeneration at 135 sites in stand-replacement patches across a gradient of fire refugia density in eastern Oregon, USA. We characterized the influence of refugial seed source pattern and other environmental factors on the abundance of regenerating seedlings, and examined the relationship between post-fire climate and the temporal pattern of ponderosa pine seedling establishment.ResultsTree seedlingswere present in 83% of plots 12-17years post-fire, and densities varied substantially (0-67800 stems ha(-1), median=1100). Variation in seedling abundance was driven by the spatial patterns of refugial seed sources. Despite widespread post-fire shrub cover, high-severity burned forests have not undergone a persistent type conversion to shrublands. Ponderosa pine seedling establishment peaked 5-11years after fire and was not closely associated with post-fire climate.ConclusionsFire refugia and the seed sources they contain fostered tree regeneration in severely burned patches. Management practices that reduce refugia within post-fire landscapes may negatively influence essential forest recovery processes.
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Reprint Address:Downing, WM (corresponding author), Oregon State Univ, Dept Forest Ecosyst & Soc, Corvallis, OR 97331 USA.
Addresses:[Downing, William M.; Krawchuk, Meg A.; Meigs, Garrett W.] Oregon State Univ, Dept Forest Ecosyst & Soc, Corvallis, OR 97331 USA. [Haire, Sandra L.] Haire Lab Landscape Ecol, Belfast, ME 04915 USA. [Coop, Jonathan D.; Walker, Ryan B.] Western Colorado Univ, Sch Environm & Sustainabil, Gunnison, CO 81231 USA. [Whitman, Ellen] Nat Resources Canada, Canadian Forest Serv, Northern Forestry Ctr, Edmonton, AB, Canada. [Chong, Geneva] US Geol Survey, Northern Rocky Mt Sci Ctr, Jackson, WY 83001 USA. [Miller, Carol] US Forest Serv, Aldo Leopold Wilderness Res Inst, Rocky Mt Res Stn, USDA, Missoula, MT 59801 USA.
E-mail Addresses:willmdowning@gmail.com