Analyses of charcoal records from lake sediments have been used to produce reconstructions of long-term local and regional fire histories. These histories often provide important information about regional paleoenvironmental conditions, ecosystem characteristics and climatic fluctuations. Previous studies have focused on differences in charcoal particle deposition between lakes with differences related to multiple processes, including the heterogeneity of landscape burning and charcoal transport processes. Variations within an individual lake basin, however, are not well understood. This study investigates the consistency of lake sediment charcoal records from an individual lake by addressing the following questions: 1) Do three cores from the same lake register consistent charcoal records? 2) What are the potential factors that influence variations in charcoal deposition within a basin?
This investigation compares the charcoal data from three cores extracted from Hidden Lake, Colorado during a single field sampling session. Each core spans the past 1500-2000 years. Two cores were sampled at one-centimeter intervals while the third was sampled at 0.5-centimeter intervals. An age model for Hidden Lake has been developed based on radiocarbon dates obtained from two of the cores, and the sample ages were used to convert the original charcoal counts to estimates of charcoal influx through time.
Results/Conclusions
Preliminary results from the three Hidden Lake cores show some synchronicity of trends in the charcoal record with several fire events registering consistently in each core record. Variations in the frequency of inferred fire events appear to be similar among cores. Patterns of charcoal influx vary, however, at the scale of specific peaks with some charcoal peaks offset in time or absent from various cores. Differences do not appear to be solely the result of potential errors in age-depth model calculations, but are instead real differences in the number and magnitude of charcoal peaks in each core. Important factors may include fire intensity and type, fire location on the lake margin, wind direction during or after fires, and basin topography. The final results from this study will provide important insight into the interpretation and comparison of lake-sediment charcoal records.
