Background/Question/Methods
In the Central Harwood Region of the eastern U.S., anthropogenic fire exclusion has contributed to upland oak (Quercus spp.) regeneration failure and a compositional shift towards shade-tolerant, fire-sensitive species (i.e., mesophytes). Because oaks are fire-adapted and relatively shade-intolerant, prescribed fire is often used as a management tool to decrease competition from mesophytes and increase understory light with the goal of promoting advanced oak regeneration. However, in practice, prescribed fire alone often fails to open the canopy sufficiently to improve oak competitive status, suggesting that multiple repeated fires and/or canopy manipulations are necessary to create the desired conditions for oak success. To examine the potentially interacting roles of multiple prescribed fires and canopy gaps, we measured upland oak and mesophyte density within two size classes, seedlings (< 1 m height) and saplings/midstory (1-7 m height), growing in gap and non-gap areas treated with no fire, a single fire, or multiple fires (2-3x) during summer 2017 at Bernheim Arboretum and Research Forest in western Kentucky.
Results/Conclusions
In the seedling size class, red maple (p = 0.0041), red oak (p = 0.0017), and white oak (p = 0.0276) density was significantly higher in gaps compared to non-gaps, but burn treatment had no impact on their densities (p = 0.0985, p = 0.9137, p = 0.8772, respectively). In the sapling/midstory size class, gaps interacted with burn treatment, leading to reduced mesophyte density (p = 0.0399) inside gaps treated with multiple burns. Single burns increased red maple sapling/midstory density (p = 0.0004) compared to unburned and multiple burns regardless of gap presence. in single and multiple burns compared to unburned areas (p = 0.0023),