Wave of fire: an anthropogenic signal in historical fire regimes across central Pennsylvania,USA

Abstract

Increasingly detailed records of long‐term fire regime characteristics are needed to test ecological concepts and inform natural resource management and policymaking. We reconstructed and analyzed twelve 350+ yr‐long fire scar records developed from 2612 tree‐ring dated fire scars on 432 living and dead pine (Pinus pungens, Pinus rigida, Pinus resinosa, Pinus echinata) trees from across central Pennsylvania. We used multiple spatial and time series analysis methods to quantify fire regime characteristics (frequency, seasonality, percentages of trees scarred, extent) and fire–climate–human associations. Prior to the 20th‐century fire suppression, fire regimes at the majority of sites consisted of frequent, low‐to‐moderate severity, dormant season fires. Fires were often regionally synchronous when preceded by significantly dry years. Using documentary archives, we provide the first description of a “wave of fire”—an anthropogenic signal in fire frequency that progressively moved across the region. This “wave of fire” reflects a changing progression of anthropogenic fire regimes from Native American occupation and depopulation, to Euro‐American settlement, to industrialization and declining fire use up to the 20th century era of fire suppression. The wave of fire provides a new perspective on historical and modern fire regime dynamics and identifies socio‐ecological impacts since North American colonization. Because the anthropogenic wave of fire exists at sites across North America, we emphasize the need for a broader determination of its geographic prevalence and variability as such determinations could influence historical ecology interpretations and perspectives on past and future roles of humans in managing ecosystems with fire.

Anthropogenic and lightning‐started fires are becoming larger and more frequent over a longer season length in the U.S.A.

“…The extent to which ignitions have limited fire across the country has varied over time and space. The prevalence of human‐started fire has fluctuated over time, from widespread use for land management activities by Native people, to declines in ignitions during industrialization, and further declines during the era of fire suppression in the 20th century, affecting fire characteristics through changes in fire frequency and fire return intervals (Van Lear & Harlow, ; Stambaugh et al, ; Taylor, Trouet, Skinner, & Stephens, ). Evidence for this so‐called ‘wave of fire’ exists in several places in North America, but it is still unknown to what extent it is geographically prevalent, which would influence our current interpretations of the influence of anthropogenic ignitions on contemporary fire regimes within the historical context of human fire‐use across broad landscapes.…”

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

“…Inventory records and dormant season aerial photos aided in identifying the locations of extant red pine stands in the landscape adjacent to the previously reported fire history study site (Stambaugh et al. ).…”

“…, Stambaugh et al. ) and reflecting modern seasonal trends in which most wildland fires occur during the early spring (Pennsylvania Department of Conservation and Natural Resources Wildfire Statistics ), fire scars were assigned to the calendar year of cambial response; therefore, dormant season fire scars (between annual rings) were assigned to the latter, rather than the preceding year. Fire event data were compiled for each tree and entered into FHX2 (Grissino‐Mayer ) and Fire History Analysis and Exploration System (FHAES; Brewer et al.…”

“…Stambaugh et al. () described temporal fire synchrony in step with Euro‐American settlement effects and the advent of modern fire‐suppression forest management policies and technology (circa 1915; Decoster ).…”

A Review on the Dynamics of Prescribed Fire, Tree Mortality, and Injury in Managing Oak Natural Communities to Minimize Economic Loss in North America

“…During the Holocene, increasing fire occurrence, often due to Native American land use practices, favored the dominance of oak-pine (Quercus/Pinus) natural communities such as forests, woodlands, and savannas in North America [5][6][7][8]. In historic times, fire frequency was highest in the oak region during the early European settlement period [9][10][11] when settlers saturated the landscape with fire and initiated a wave of fire that rolled from the eastern seaboard to the tallgrass prairies [12,13]. Widespread catastrophic fires, which burned in logging slash circa the 1850s to 1920s, caused severe destruction on millions of acres and took thousands of lives, bringing the need for wildfire control to national attention.…”