Silvicultural treatments alter fuel dynamics in forested systems, which may alter fire regime. Effects of thinning and prescribed fire on forest-floor fuels were studied in mixed-oak forests of south-eastern Ohio to examine fuel dynamics over time. Fuel characteristics were measured before, immediately after, and 3 years following fire and thinning treatments along 20-m transects (n = 432) following Brown’s planar intersect method. Measurements were taken to determine litter, duff, 1-h, 10-h, 100-h, and 1000-h sound (1000S) or rotten (1000R) fuel mass. Coarse woody debris (CWD) was sampled on 432 additional 80-m2 belt-transects. Repeated-measures analysis of variance with post-hoc Bonferonni comparisons was used to analyse the change in the fuels over time. The specific effects of silvicultural treatments varied over time with changes in larger, sound fuels (1000S and CWD) persisting longer than changes to finer (litter, duff, 1-h, 10-h, and 100-h) or less-sound (1000R) fuels, which appear to be more transient. Unlike in western North America where fuels accumulate over time, decomposition and productivity appear comparable in eastern mixed-oak forests. Aside from their impact on decomposition or productivity rates, silvicultural treatments appear to have little impact on fine-fuel loading in these systems.

Multiple factors interact to influence fire behavior. While the interactions of fuel moisture and fuel loading in western coniferous communities are well understood, few studies have examined fire behavior in eastern deciduous forests. In order to accurately predict fire behavior in mixed- oak forests, studies need to examine fire behavior in eastern deciduous forests. We conducted a fine-scale manipulative experiment to determine the specific effects that fine fuel moisture and load have on fire behavior in Ohio mixed-oak forests. Three fuel moisture levels (0, 4, and 15% moisture), and five field-simulated fuel loads were burned in a 3×5 factorial experiment. Thermocolor pyrometers were used to measure maximum temperature at 5 and 30 cm as an indicator of fire behavior. Additionally, amount and percent of fuel burned were determined for each set of conditions. As expected, fires burned hotter with decreasing fuel moisture, and with increasing fuel load. Percent of fuel burned and mean temperature at 5 and 30 cm were positively correlated. Interactive effects were not observed. Temperatures were similar to those found in prior field studies in Appalachian Ohio. Controlled experiments such as this will likely prove useful in future efforts to link fuel conditions and fire behavior as landscape-scale effects are modeled. In particular, our results can be used to verify and calibrate fire behavior models in eastern mixed-oak forests.

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