Question: What was the role of fire in montane pineoak (Pinus-Quercus) stands under changing human land uses on a temperate forest landscape in eastern North America? Location: Mill Mountain in the central Appalachian Mountains, Virginia, US. Methods: A dendroecological reconstruction of fire history was generated for four stands dominated by xerophytic pine and oak species. The fire chronology began under presettlement conditions following aboriginal depopulation. Subsequent land uses included European settlement, iron mining, logging, and US Forest Service acquisition and fire protection.
A dendroecological fire history study was conducted for The Nature Conservancy's Narrows Preserve on Peters Mountain, Virginia, where the predominant vegetation is oak (Quercus L.)-dominated forest containing some other hardwoods and pines (Pinus L.). The site encompasses all the known habitat of the endangered and endemic Peters Mountain mallow (Iliamna corei Sherff.), a perennial herb that requires fire for seed germination and habitat maintenance. Fire scars from 73 pines indicate frequent burning in the past (Weibull median composite fire interval = 2.2 years), primarily during the dormant season. Fire frequency exhibited little temporal variability from the beginning of the fire chronology in 1794 until the 1940s, despite changing land uses. However, the incidence of fire declined subsequently with the advent of effective fire protection measures. Ageing trees near the mallow population indicates that the fire-tolerant chestnut oak (Quercus montana Willd.) recruited relatively continuously under frequent fire, but that other species were established primarily during the fire protection era. The decline in burning appears to have permitted an increase in tree density that likely inhibits the growth and recruitment of mallow plants. Our results suggest that reintroducing frequent fire would be an appropriate technique for managing the mallows and the greater Peters Mountain landscape. [
Aim
Our aims were to: (1) reconstruct the fire history of pine–oak forests in the central Appalachian Mountains, USA, with an annual resolution over as long a time period as possible using dendroecological techniques; (2) estimate the frequency of fire in the study area before the fire‐suppression era; and (3) investigate how variations in land use and climate have affected the occurrence of fire in the study area.
Location
Temperate forests at three study sites within the central Appalachian Mountains, Virginia, USA.
Methods
Cross‐sections were taken (sawn) from fire‐scarred pine (Pinus L.) trees growing in pine‐dominated patches within a hardwood forest matrix. Dendroecological techniques were used to date the scars, which were used to calculate fire intervals. A variety of analyses were carried out: Pearson correlation analysis, to investigate whether fire activity varied over time (under changing land uses); Kruskal–Wallis analysis, to examine whether fire frequency varied spatially (among study sites); chi‐square analysis, to test whether scar seasonality changed temporally; and superposed epoch analysis, to explore whether fire activity was associated with interannual climatic variations in moisture, as characterized by the Palmer drought severity index (PDSI).
Results
Fire scars dated back to the 17th or early 18th century (depending on site). The filtered composite fire interval, considered to be a particularly reliable estimate of fire interval, averaged between 6 and 8 years. Fire frequency remained fairly constant from the beginning of the record until effective fire suppression began in the early 20th century, after which burning virtually ceased. Fire occurred more frequently at the easternmost site, which was located in the Blue Ridge province of the Appalachian Mountains, than at the other two sites, in the Ridge and Valley province. Scar seasonality showed no discernible trend over time. Fire was associated with low PDSI (i.e. dry years) at two of the study sites.
Main conclusions
Fire occurred frequently at these central Appalachian study sites during the period of aboriginal depopulation that preceded European colonization, and throughout the periods of European settlement and industrialization (with mining, logging and railroads) that followed. Our results match those from other fire‐history sites in the central and southern Appalachian Mountains, and suggest that fire was an important factor influencing vegetation development in the temperate forests covering this region.
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