Fire history, related to climate and land use in three southern Appalachian landscapes in the eastern United States

Abstract

Fire-maintained ecosystems and associated species are becoming increasingly rare in the southern Appalachian Mountains because of fire suppression policies implemented in the early 20th century. Restoration of these communities through prescribed fire has been hindered by a lack of information on historical fire regimes. To characterize past fire regimes, we collected and absolutely dated the tree rings on cross sections from 242 fire-scarred trees at three different sites in the southern Appalachian Mountains of Tennessee and North Carolina. Our objectives were to (1) characterize the historical frequency of fire in southern Appalachian mixed pine-oak forests, (2) assess the impact of interannual climatic variability on the historical occurrence of fire, and (3) determine whether changes in human culture and land use altered the frequency of fire. Results demonstrate that fires burned frequently at all three sites for at least two centuries prior to the implementation of fire suppression and prevention in the early to mid 20th century. Composite mean fire return intervals were 2-4 yr, and point mean fire return intervals were 9-13 yr. Area-wide fires that burned across multiple stands occurred at 6-13-yr intervals. The majority of fires were recorded during the dormant season. Fire occurrence exhibited little relationship with reconstructed annual drought conditions. Also, fire activity did not change markedly during the transition from Native American to Euro-American settlement or during the period of industrial logging at the start of the 20th century. Fire activity declined significantly, however, during the fire suppression period, with a nearly complete absence of fire during recent decades. The characterization of past fire regimes should provide managers with specific targets for restoration of fire-associated communities in the southern Appalachian Mountains. The fire chronologies reported here are among the longest tree-ring reconstructions of fire history compiled for the eastern United States and support the hypothesis that frequent burning has played a long and important role in the development of forests in the southern Appalachian Mountains.

Fire Regimes of Remnant Pitch Pine Communities in the Ridge and Valley Region of Central Pennsylvania, USA

“…MFIs did not differ statistically between sites or time periods, except for the pre-European and European settlement time periods at SGL 107 (Table 1). During the pre-European time period, SGL 107 had two significantly long fire intervals (1664-1701, 1701-1729; Figure 3); interestingly, both The fire frequencies reported here are comparable to those of two previous studies conducted in yellow pine forests of the Ridge and Valley Province [65,66], located approximately 750 and 420 km to the south, respectively. Another study, also to the south, but closer (approximately 180 km) on the Appalachian Plateau, also reported similar fire frequencies from white oaks [67].…”

Forest Disturbance History from ‘Legacy’ Pitch Pine (Pinus rigida) at the New River Gorge, West Virginia

“…Land use change, including a reduction in grazing activities, and a decrease in population density coincided with fire cessation in this mountain landscape. Farther south at sites in the Blue Ridge Mountains of North Carolina and in the Ridge and Valley and Blue Ridge physiographic regions of eastern Tennessee, fire cessation dates were in the 1950s, 1960s, and 1930s, respectively (Flatley et al 2013). In each case, it was shown that fires occurred regularly from the late 1700s through the end of the industrial logging era.…”

“…The prevalence of anthropogenic fires throughout the fire record may have masked a stronger climate-fire association (McEwan et al 2007;Flatley et al 2013). Fire events generally occurred during dry years (see Figure 5a) and there was a significant association between drought and growth release events (Figure 5b), suggesting that fire was driven by periodic drought, in addition to early settlement and industrial activities.…”

Spring and Autumn Phenological Variability across Environmental Gradients of Great Smoky Mountains National Park, USA

“…and hickory (Carya spp.) [56,57]. Virginia pine (P. virginiana) is locally common, especially in xeric, low elevation sites that are regenerating from past agricultural clearing.…”