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.

Key Words:

• indicator kriging
• inverse distance weighting
• paleo-fire
• ponderosa pine
• ROC plot

Notes

Note: Record=trees capable of recording fire; Scar=number of trees scarred by fire; Train=number of trees in the training data set; and Thresh=the threshold used to define fire maps.

Note: All p values are <0.001. IK=indicator kriging; IDW=inverse distance weighting; TP=Thiessen polygons.

Additional information

Notes on contributors

Amy Hessl

An Assistant Professor

Jennifer Miller

An Assistant Professor

James Kernan

An instructor of geography

David Keenum

A forester

Don McKenzie

A research ecologist