Midterm Response of Understory Plant Communities after Different Regeneration Treatments in Temperate Hardwood Forests of Quebec, Canada
| Authors: | Romain Jaeger, Sylvain Delagrange, Isabelle Aubin, Gilles Joanisse, Patricia Raymond, David Rivest |
| Year: | 2023 |
| Type: | Proceedings - Paper |
| Station: | Northern Research Station |
| DOI: | https://doi.org/10.2737/NRS-GTR-P-211-paper41 |
| 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: 203–211. |
Abstract
Short-term effects of disturbances intensity on understory plant communities are well documented, however, only few studies have examined longer term effects. While increased intensity of soil and canopy disturbances tend to increase species richness in the short term due to early seral-species establishment, those competitive-pioneer species emerging from early stages of succession can become recalcitrant, which can alter patterns of natural regeneration especially by being detrimental to rarer species and such functional groups associated with closed forest habitats. We measured taxonomic and functional diversity indices and soil properties using four levels of disturbance intensity in six temperate hardwood forests of Quebec distributed along a longitudinal gradient. Reference forests—i.e., control forests with no silvicultural treatment known for ≥80 years (control: CON, n=21)—were compared to 20-year-old single-tree selection cuts (SIN, n=13), 20-year-old group-selection cuts (GRP, n=15), and 20-year-old group-selection cuts with soil scarification (GRPS, n=17). Species richness in group-selection treatments was higher than that in reference forests. Plant equitability and beta diversity among sites in GRP and GRPS were lower than in SIN and CON forests. More intense treatments (i.e., GRP and GRPS) contributed to the midterm persistence of early-successional competitor species (i.e., Rubus idaeus, Prunus pensylvanica) whereas sensitive species (e.g., Monotropa uniflora, Dryopteris spinulosa) occurred less often in stands with soil scarification. Of the 20-year-old treatments studied, single-tree selection cutting appears to be the most appropriate silvicultural treatment for maintaining heterogeneous understory plant communities with compositions and structures like natural forests—while more intense treatments maintain and expand for at least 20 years—species that are better adapted to a wider range of environmental conditions, including open environments.