Thinning, burning, and bees: Evaluating pollinator responses to forest management in Utah's Uinta Mountains

Decades of wildfire suppression have left forests across the U.S. overgrown and laden with potential fuel for wildfires. In Utah’s Uinta Mountains, the U.S. Forest Service is conducting a multi-year project involving forest thinning and pile burning to reduce fuel loads and improve forest health. After selected trees are removed, the woody material is placed into slash piles, which are later burned under appropriate conditions. This project has two main objectives: (1) to compare native bee abundance and diversity across thinned, thinned-and-burned, and untreated sites, and (2) to evaluate slash piles as potential nesting habitat for cavity-nesting bees and determine burn timing that minimizes disruption to their life cycles.
To investigate the latter, we installed screened enclosures over slash piles of three age classes and fitted them with blue vane traps to passively collect insects emerging from the piles. Cavity-nesting bees in this region depend on preexisting cavities, often created by wood-boring beetles such as Buprestids and Cerambycids, making the age of felled wood an important factor. While the broader goal is to assess how forest treatments affect native bee communities, we are particularly interested in the potential of slash piles to serve as nesting habitat for cavity-nesting species. Ultimately, this research aims to inform land managers on how fuel reduction strategies—specifically thinning and pile burning—can be aligned with pollinator conservation goals. By integrating ecological insights into forest management practices, we hope to support both wildfire mitigation and biodiversity preservation in managed forest landscapes.