Natural and prescribed fires play an important role in managing and maintaining most ecosystems in the western US. The high soil temperatures associated with fire influence forests and their ability to regenerate after a fire by altering soil properties and soil chemistry and by killing soil microbes, plant roots, and seeds. Because prescribed fire is frequently used to reduce surface fuels, it is important to know how fuel conditions, soil moisture, and soil properties interact to determine the nature and extent of the soil heat pulse and the response of the soil biota. This report presents the results of experimental tests of a high temperature soil heat flux plate and a high temperature soil moisture probe. These sensors are intended to provide data before, during, and after a prescribed burn and to support long term monitoring of soil microbial response to fires. In both experiments the upper 2 cm of soil was heated to about 400 C while each sensor had a nominal depth of 5 cm. Results suggest (1) that the soil heat flux plate, rated to at about 750 C, performed successfully and (2) that a simple redesign of the soil moisture probe, which is rated to about 250 C, should permit it to survive higher temperatures than achieved during these preliminary tests. Nevertheless, the soil moisture probe did provide some of the first observations of soil moisture dynamics during and after a controlled burn.