Abstract
Lowland conifer forests dominated by black spruce (Picea mariana) and tamarack (Larix laricina) typically occur in peatlands in the boreal North American forest with near-surface water tables throughout the year. These forests are ecologically and economically important resources that may be impacted by climate change. However, information characterizing effects of forest disturbance, such as even-aged harvest on water table dynamics is needed to evaluate which forest tree species cover types are most hydrologically susceptible to even-aged harvest and changes in precipitation. We used a chronosequence approach to evaluate water table fluctuations and evapotranspiration across four stand age classes (<10, 15–30, 40–80, and >100-years old) and three distinct forest cover types (productive black spruce, stagnant black spruce, and tamarack) for a period of three years in Minnesota, USA. In general, there is limited evidence for elevated water tables in the younger age classes; the <10-year age class had no significant difference in mean weekly water table depth compared to the older age classes across all cover types. Estimated actual daily evapotranspiration (ET) generally agreed with the water table observations, with the exception of the tamarack cover type where ET was significantly lower in the <10-year age class. Productive black spruce sites that are 40–80-years old had higher evapotranspiration, and lower water table, possibly reflecting increased transpiration associated with the stem exclusion stage of stand development. Tamarack in the 40-80-year age class had higher water tables but no difference in ET compared to all other age classes, indicating that other external factors are driving higher water tables in that age class. To evaluate susceptibility to changing climate, we also assessed the sensitivity and response of water table dynamics to pronounced differences in growing season precipitation that occurred across study years. In general, tamarack forests are more sensitive to changes in precipitation compared to the two black spruce forest cover types. These findings can inform expected responses of site hydrology for a range of precipitation scenarios that may occur under future climate and be used by forest managers to evaluate hydrologic impacts of forest management activities across lowland conifer forest cover types.
Original language | English |
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Article number | 117783 |
Journal | Journal of Environmental Management |
Volume | 339 |
DOIs | |
State | Published - Aug 1 2023 |
Externally published | Yes |
Funding
This research was funded by the Environmental and Natural Resources Trust Fund as recommended by the Legislative Citizen Commission of Minnesota's Resources. We would like to thank Alan Toczydlowski, Josh Bednar, Steve Kolbe, Laura Rueling, Mike Tuma for assisting with site selection, instrumentation, and measurement. Special thanks to Leslie Brodie for producing Fig. 1. We also gratefully acknowledge the Minnesota Department of Natural Resources for partnering with us and providing the sites involved in this study. Finally, we would like to thank the anonymous reviewers that have improved the quality of this manuscript. This research was funded by the Environmental and Natural Resources Trust Fund as recommended by the Legislative Citizen Commission of Minnesota's Resources. We would like to thank Alan Toczydlowski, Josh Bednar, Steve Kolbe, Laura Rueling, Mike Tuma for assisting with site selection, instrumentation, and measurement. Special thanks to Leslie Brodie for producing Fig. 1 . We also gratefully acknowledge the Minnesota Department of Natural Resources for partnering with us and providing the sites involved in this study. Finally, we would like to thank the anonymous reviewers that have improved the quality of this manuscript.
Funders | Funder number |
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Legislative Citizen Commission of Minnesota | |
Minnesota Department of Natural Resources | |
Minnesota Environment and Natural Resources Trust Fund |
Keywords
- Climate change
- Evapotranspiration
- Hydrology
- Peatland
- Water table