Tree Regeneration Response to Variable-Sized Group Selection Harvest Gaps in Northern Wisconsin
| Authors: | David K. Schnake, Jodi A. Forrester, Andrew J. Sanchez-Meador, David J. Mladenoff, Craig Lorimer |
| Year: | 2023 |
| Type: | Proceedings - Paper |
| Station: | Northern Research Station |
| DOI: | https://doi.org/10.2737/NRS-GTR-P-211-paper8 |
| 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: 32–37. |
Abstract
We established a field experiment in an even-aged, second-growth northern hardwood forest in north-central Wisconsin, testing the response of tree regeneration to deer exclusion and group-selection harvesting where small (50 m2), medium (200 m2), and large (380 m2) gaps were created. We measured occurrence and height of saplings 9 years post-treatment and modeled incoming solar radiation in gaps to assess light distribution across the gap environments. Densities of tolerant and midtolerant saplings were similar in medium and large gaps but tolerant saplings outnumbered midtolerants approximately four to one in small gaps. However, tolerant saplings averaged two meters taller than midtolerants across gap sizes. Deer exclusion increased midtolerant-sapling density but did not influence tolerant-sapling density. Modeled light levels decreased with gap size and varied by position within gaps. We attribute the increases in tree diversity in gaps over 200 m2 to higher light levels across medium and large gaps.