Spatial variability of historical fires across a red pine–oak landscape, Pennsylvania,USA

Abstract

Long‐term, ecosystem‐specific fire regime information improves natural community restoration and management by providing a basis for scientifically reasoned fire management prescriptions. Historical fire regimes can be reconstructed to sub‐annual resolution using fire‐scarred trees, and while such reconstructions have become increasingly prevalent across the eastern USA, little information regarding how they vary at landscape scale is available. Most studies report fire regime characteristics (i.e., frequency, seasonality) at site‐composite levels, commonly at ≤1 km2 spatial resolution. In this study, we analyzed the historical spatial variation of fire regime characteristics over the past four centuries (1620 CE to present) in a red pine/oak landscape (30.75 km2) in north‐central Pennsylvania, USA. Fire event data were reconstructed based on fire scars and locations of 192 living and dead red pines. The spatial and temporal distributions of fire scars revealed a historical fire regime dominated by frequent, dormant season fires most often detected at relatively small spatial extents and by relatively few trees. There was, however, evidence of less frequent, relatively large fires that scarred high percentages of trees. These fire regime characteristics likely resulted in a spatially and temporally transient patchwork of varying vegetation age and structures resulting in a heterogeneous landscape. At the landscape scale, fire frequency changed with human cultures, while fire spatial extent and scarring patterns appeared to be modulated by drought conditions. Results from this study show historical precedence for landscape‐scale burning across a broad range of drought conditions and spatial extents, which should be considered when designing fire‐management and ecosystem restoration objectives.

Revealing historical fire regimes of the Cumberland Plateau, USA, through remnant fire-scarred shortleaf pines (Pinus echinata Mill.)

“…For fires between SAV and AAFB specifically, prevailing westerly winds and upslope directions from the Eastern Highland Rim towards the Cumberland Plateau means that fires could have spread to the Plateau and have some commonality in fire years. Further expansion of sampling fire-scarred trees at new locations within the Savage Gulf landscape would aid in determining the spatial extent of fires beyond a single site (e.g., Marschall et al 2019) and making more robust linkages to the AAFB sites.…”

Reviewing Fire, Climate, Deer, and Foundation Species as Drivers of Historically Open Oak and Pine Forests and Transition to Closed Forests

“…Evidence continues to accumulate that frequent surface fires occurred historically every 2 to 25 years in most of the eastern United States, based on studies of fire scars, charcoal, contemporaneous accounts, and dominance by fire-tolerant trees ranging back 12,000 years, until fire exclusion during the first half of the 1900s (Gleason, 1922;Bromley, 1935;Day, 1953;Delcourt and Delcourt, 1987;Wade et al, 2000;Parshall and Foster, 2002;Williams, 2005;Stambaugh et al, 2015Stambaugh et al, , 2018Hanberry and Nowacki, 2016;Abadir et al, 2019;Abrams and Nowacki, 2019;Hutchinson et al, 2019;Marschall et al, 2019). The eastern United States has areas of great lightning strike frequency and in pre-industrial societies, fire was the primary tool to clear forests for shifting agricultural cultivation as well as to open forests for plants and associated game animals and for ease of movement (Fuller et al, 1998;Brown, 2000;Brose et al, 2001;Whitney and DeCant, 2003;Williams, 2005;Bowman et al, 2013;Varner et al, 2016a).…”

Pre-Columbian red pine (Pinus resinosa Ait.) fire regimes of north-central Pennsylvania, USA

“…Tree-ring and fire-scar chronologies developed from dead trees (i.e., remnant wood in the form of stumps or snags) have the capacity to provide such information. These archives provide sub-annually precise, spatially explicit fire occurrence information that can be analyzed across a range of spatial scales (e.g., tree to landscape) (Farris et al 2010;Marschall et al 2019;Rolstad et al 2017), allowing for improved understanding of historical fire regimes, vegetative community structure and composition, and associated ecological processes and vegetation community outcomes (Swetnam et al 1999). Such records can also help clarify the relative influences of climate and Native American land use practices as fire regime controls (Abrams and Nowacki 2021; Oswald et al 2020).…”

“…Existing research indicates that considerable potential exists to develop temporally long fire-scar chronologies using red pine (P. resinosa Ait.) remnant wood (e.g., Brose et al 2013Brose et al , 2015Kipfmueller et al 2021;Mann et al 1994;Marschall et al 2019). Red pine is an ideal tree species for fire-scar chronology development due to its abilities to survive and record low-to-moderate severity fires (Hauser 2008), and to persist as remnant wood for centuries post-mortem.…”

“…In the landscape included in this study, fire-scar chronologies previously developed extend to 1620 AD (Marschall et al 2019;Stambaugh et al 2018). Results from these studies showed that before fire suppression and exclusion efforts began circa 1915, fires occurred on average every two to three years at the landscape scale and were generally dormant season, small-scale events, with fire extent and scarring synchrony modulated by antecedent drought (Marschall et al 2019). Fire frequency from the seventeenth to twentieth centuries was closely associated with changes in human populations and culture (Stambaugh et al 2018).…”