The role of fire during climate change in an eastern deciduous forest at Devil's Bathtub, New York

Annual records of charcoal and sedimentation rate were compared with fossil pollen to investigate the role of fire in eastern deciduous forest around Devil's Bathtub, New York, USA. Changes in peak and background charcoal suggest that changes in fire regime have accompanied the principal vegetation and climatic changes of the last 10400 yr. A distribution of return times (50-200-yr intervals) similar to parts of modern boreal Canada prevailed when late-Glacial spruce woodland dominated the site. Expansion of Pinus banksiana appears to have altered the fire regime to one of crown fires with high particulate emissions, but return intervals similar to those of the preceding Picea forest. Expansion of Pinus strobus might be linked to change in fire occurrence, but the broad dispersal of Pinus pollen makes interpretation difficult. If Pinus strobus expansion around the site is reflected in its pollen curve, then that expansion coincides with a time of frequent fire. Alternatively, if increasing pollen abundance precedes the local expansion of trees, as has been observed elsewhere, then local expansion might correspond to an abrupt decline in fire frequency and in regional importance of fire. An abrupt decline in background charcoal follows a fire and coincides (±100 yr) with the expansion of hardwood taxa such as Fagus. The decline in background charcoal occurs over several years, suggesting that it may be linked to effects of hardwood expansion on fuels. Fires do not appear to have occurred during the time of hardwood dominance, suggesting that fire may not be an explanation for maintenance of species diversity in this deciduous forest. However, frequent occurrence of thick varves during the latter half of the Holocene suggests that the frequency of other types of disturbance may have increased.

Duke Scholars

Author James S. Clark Environmental Sciences and Policy