Forest [FAR1]

Invasive species such as European buckthorn and reed canarygrass are generally expected to benefit from longer growing seasons, disrupted ecosystems, and warmer temperatures, but it's hard to predict exactly how they may be affected by climate change.

Longer growing seasons and milder winters might allow populations of native forest pests to build more rapidly, and many pests have been shown to be more damaging when interacting with trees that are already stressed due to droughts or other impacts. It also seems very likely that the emerald ash borer will reduce the amount of green and black ash in northern Minnesota.

Multiple forest impact models tend to agree that these species are more likely to increase in suitable habitat and biomass across a range of climate scenarios by the end of the century. These forests also contain several species at their northern range limits, which may benefit from gene flow between southern populations. These species are generally adapted to thrive in riparian settings, so Floodplain Forests may be at a low risk to transition to other forest types.

Floodplain Forests are adapted to periodic disturbances and fluctuating soil moisture, so they might be capable of tolerating future changes to the hydrologic cycle. Heavy precipitation events have been increasing in Minnesota, and this trend is expected to continue under climate change. The possibility for warmer and wetter conditions and winter and spring might also leads to more flooding in these seasons. More flood events might not necessarily be harmful to Floodplain Forests, but some systems may be at risk of excessive waterlogging and downcutting of riverbanks.

Floodplain Forests are adapted to seasonal and annual floods. The regeneration requirements of several species within this system are also linked to these floods. If climate change results in shifts in the timing or volume of stream flows, this forest system could be impaired. This risk may be higher in watersheds that have already been altered with dams, river channelization, or developed floodplains.

Mesic Hardwood Forests that contain a diversity of species, age classes, and structures may be more resilient to changing conditions than forests with few species and uniform age classes and structure. Diversity in all of these features can give a forest more possible pathways to respond to changing or unexpected conditions.

The potential exists for negative interactions between stressors in this system, such as earthworms, herbivory, drought, and invasive species. Each of these stressors is generally expected to be more damaging under climate change, but it's hard to predict how they may act in combination.

The potential for climate change to increase the frequency of extended droughts poses a threat to these forests for multiple reasons, including increased moisture stress, wildfire occurrence, and susceptibility to other stress agents. Hardwood forests occurring on moist, rich soils may be buffered from short-term droughts or seasonal moisture stress. CO2 fertilization might also increase the water-use efficiency of some species, reducing the risk of moisture stress.

Longer growing seasons and milder winters might allow populations of native forest pests such as forest tent caterpillar to build more rapidly, and many pests have been shown to be more damaging when interacting with trees that are already stressed due to droughts or other impacts. The possibility also exists for new pests such as gypsy moth and Asian longhorn beetle to arrive in northern Minnesota.

Multiple forest impact models tend to agree that these species are more likely to increase in suitable habitat and biomass across a range of climate scenarios by the end of the century. These forests also contain several species at their northern range limits, such as sugar maple and northern red oak, which may benefit from gene flow between southern populations.