Mapping Paleo-Fire Boundaries from Binary Point Data: Comparing Interpolation Methods

Abstract

Fire history studies have traditionally emphasized temporal rather than spatial properties of paleo-fire regimes. In this study we compare four methods of mapping paleo-fires in central Washington from binary point data: indicator kriging, inverse distance weighting, Thiessen polygons, and an expert approach. We evaluate the results of each mapping method using a test (validation) dataset and receiver operating characteristic plots. Interpolation methods perform well, but results vary with fire size and spatial pattern of points. Though all methods involve some subjectivity, automated interpolation methods perform well, are replicable, and can be applied across varying landscapes.

Topography affected landscape fire history patterns in southern Arizona, USA

“…Relative area burned for each widespread fire year was estimated based on the proportion of recording plots scarred. This measure is similar to the area burned index used by Taylor and Skinner (2003) in their landscape/fire analyses and provides estimates similar to other area burned indices (Heyerdahl et al, 2001;Iniguez, 2006;Hessl et al, 2007). Fire size differences between landscapes were compared using chi-square goodnessof-fit test.…”

“…By ''spatially explicit'' we mean intensively studied landscapes where firescarred trees were systematically and/or randomly sampled in fine-scale grids and networks. Such sampling designs enable spatial estimates of the extent of individual fires within a study area, and provide a more robust data set for statistical assessment of fire interval distributions and tests for differences in measures of central tendency (e.g., Heyerdahl et al, 2001;Taylor and Skinner, 2003;Hessl et al, 2007).…”

Climate drivers of regionally synchronous fires in the inland Northwest (1651 - 1900)

“…Over the past decade, a network of crossdated surface-fire chronologies has been developed from fire scars across the inland Northwest, with 15 sites sampled over 7 degrees of latitude in the interiors of Oregon, Washington and British Columbia (Everett et al 2000;Heyerdahl et al 2001Heyerdahl et al , 2007Daniels and Watson 2003;Hessl et al 2004;Wright and Agee 2004). The climate drivers of fire have been analysed for many of these sites individually or in small groups of sites Daniels and Watson 2003;Hessl et al 2004;Wright and Agee 2004).…”

Modern calibration and historical testing of small-area, fire-interval reconstruction methods

“…Fortunately, sequential low-severity fires may keep scars from healing for long periods (McBride 1983;Baker and Dugan 2013). Also, firerotation errors should be minimal given accurate area-burned interpolation methods (Hessl et al 2007) and a sufficient sample of trees; 15-25 trees were adequate in a study of scarring in northern Arizona (Baker and Dugan 2013).…”

“…However, it is unclear whether there is an advantage to generally using these small-area methods, as landscape-scale methods that reconstruct fire-year maps to estimate fire rotation (e.g. Farris et al 2010) are reliable and spatially explicit (Hessl et al 2007). Managers tasked with restoring fire across large, variable landscapes, such as the South Rim of GCNP (e.g.…”