Impacts of a Hickory Decline Event and Implications for Bitternut Hickory
| Authors: | Kelsey A. Bakken, Jodi A. Forrester, David J. Mladenoff, Zakiya Leggett, Jennifer Juzwik, Robert M. Jetton |
| Year: | 2023 |
| Type: | Proceedings - Paper |
| Station: | Northern Research Station |
| DOI: | https://doi.org/10.2737/NRS-GTR-P-211-paper49 |
| Source: | In: Kern, Christel C.; Dickinson, Yvette L., eds. Proceedings of the first biennial Northern Hardwood Conference 2021: Bridging science and management for the future. Gen. Tech. Rep. NRS-P-211. Madison, WI: U.S. Department of Agriculture, Forest Service, Northern Research Station: 231–235. |
Abstract
Between 2010 and 2016, rapid and extensive mortality of bitternut hickory (i.e., 35 percent year-1) was observed within a long-term experimental site in Wisconsin. The purpose of this study was to document and quantify the mortality, investigate stem-density impacts on mortality, and assess remaining hickory regeneration. Similar mortality has been reported in the midwest and northeast United States, and a pathogenic fungus (Ceratocystis smalleyi Johnson and Harrington) and hickory bark beetle (Scolytus quadrispinosus Say) were identified as the causal agents, herein investigated via a post hoc analysis. Larger hickory stems (i.e., ≥20 cm d.b.h.) experienced higher mortality rates than smaller stems (i.e., 10 to <20 cm d.b.h.). Density (i.e., percent hickory), crown class, and diameter were statistically important in predicting hickory mortality. Maintaining this species is increasingly important, especially as other dominant species, such as ash, are also decreasing. Management actions such as selective thinning will be important in mitigating these rapid hickory declines.