Monitoring Fire Effects for Managed Burns and Wildfires: Coming to Terms with Pseudoreplication

van Mantgem, Phillip; Schwartz, Mark; Keifer, Marybeth

Collecting unbiased monitoring data on fire effects is often problematic. Samples collected for assessing the effects of managed (prescribed) fires and wildfires are often "pseudoreplicated" because it is impossible to replicate the disturbance event. Furthermore, monitoring data for managed fires and wildfires may be confounded because it is difficult to randomize the effects of fires not under strict experimental control. It is not possible to replicate or randomize large-scale events such as wildfires and many prescribed fires, yet there are techniques that can account for some of the bias introduced by these problems. Since monitoring usually involves repeated observations, this paper discusses simple time-series analysis, along with two common modifications: impact/reference designs and before/after comparisons. While there are many possible monitoring strategies, most monitoring efforts are covered by these broad categories. In this paper we attempt to outline the assumptions, strengths, and limitations of these methods. We recommend four primary strategies to improve the confidence of findings when assessing fire effects: (1) acknowledge pseudoreplication in the data when it exists; (2) expand the use of managed fire and wildfire data for quantifying fire effects; (3) increase the use of unburned reference sites to improve the confidence of analyses of fire effects; and (4) in some instances, consider treating data taken from multiple fires as independent replicates. The concepts discussed in this paper are illustrated by examples taken from data sets for prescribed fire effects in Sequoia and Kings Canyon National Parks, California, USA.

Monitoring Fire Effects for Managed Burns and Wildfires: Coming to Terms with Pseudoreplication

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