Forested watershed

Sphagnum moss, the primary source of peat in these systems, may be susceptible to warmer conditions. Warmer growing seasons may increase evapotranspiration rates and reduce the rate of peat accumulation in these forests, and peat layers may begin to erode as decomposition rates increase.

Lowland conifer forests function in a relatively narrow window of water table conditions. Climate change has the potential to alter the precipitation patterns and soil moisture regimes in low-lying areas across the Upper Midwest. Roads and other watershed modifications are already harming lowland conifer forests in some areas. Water table impacts may be intensified as the hydrologic cycle becomes more episodic. Larger lowlands may be able to withstand a wider range of conditions than small, isolated depressions.

Low species diversity gives these forests few alternatives if conditions shift beyond tolerable limits, and low genetic diversity is a concern for red pine in particular.

Under a high emissions scenario, researchers forecast more insect pest damage in northern forests due to increased metabolic activity in active periods and increased winter survival. Drought-stressed trees are also typically more vulnerable to insect pests and diseases. The possibility exists for new pests such as western bark beetles to arrive in Michigan.

White pine can tolerate a wide range of soil and moisture conditions. This species may do well with a moderate amount of future warming, but models indicate that white pine will fare worse under hotter, drier climate scenarios.

This species is already near its southern range limits in Michigan. Multiple forest impact models tend to agree that red pine is likely to decline in suitable habitat and biomass across a range of climate scenarios by the end of the century. Red pine may be limited by warm temperatures, so projected warming may exceed the physiological limits of this species. Management has maintained red pine across much of the assessment area, and regeneration of this species usually relies on planted seedlings.

Runoff is expected to increase due to an increase in heavy precipitation events, leading to soil erosion. Erosion may be a concern especially in the western part of the assessment area, where glades are located on steeper slopes. Soil erosion may be less of an issue in glades east of the Mississippi, which are on more level terrain.

Red and white pine can thrive with regular surface wildfires. Conditions that promote wildfires are generally projected to become more common in northern Michigan by the end of the century. Greater wildfire activity could be positive for these forest types. The on-going shift toward mesic species in these forests is a current threat, and this trend may continue if fire suppression activities remain constant and broadleaf species like red maple and black cherry increase under climate change.

Forest impacts models do not project a substantial change in habitat suitability for eastern redcedar under a range of climate scenarios. However, eastern redcedar is already expanding in the area due to fire suppression and will likely expand further.

Climate change impact modeling under multiple scenarios suggests that habitat suitability for post oak will increase over the next century.