Charster is designed to ease the exploratory analysis of lake-sediment or bog/peatland charcoal records when the purpose is to identify peaks in the charcoal record that result from nearby fires. Charster provides a few statistical tools that help characterize the variability in the charcoal record and whether identification of peaks is warranted. Charcoal time series may be manipulated in various ways before placing a threshold to identify peaks.
Charster is most helpful for analysis of charcoal records that display distinct peaks. Recent collaboration among several labs has led to agreement on the conditions that yield such a record (see also Whitlock and Larsen 2002; Whitlock and Anderson 2003):
The general approach of this analysis is to "decompose" a time series into two components: a slowly varying background and a high frequency peak component (Long et al., 1999). One may make different assumptions regarding the behavior of these two components (i.e., nature of variability over time, relationship to local fires, etc.), prompting different methods of analysis. The purpose of Charster is to allow one to easily explore these options and their impact on the final interpretation.
Comparison with CharAnalysis
by Phil Higuera, grew out of the analyses in Charster.
CharAnalysis provides many more diagnostic statistics for
in charcoal records, including the ability to define thresholds using
local criteria and analyze fire-interval distributions. Some
other practical differences between the programs are 1) Data input
format and treatment of missing data-gaps, 2) Charster's capacity to do
simple analyses on non-interpolated data (while interpolation is
necessary for more complex analyses in Charster and is the default in
CharAnalysis), and 3) Many useful graphs produced by CharAnalysis.
This software was written by Daniel Gavin. Please read my software disclaimer.
updated 25 April 2008