![]() ![]() ![]() The economic impacts to both the forestry industry and woodland landowners manifests through reduced timber values. In the upper Midwest, the duration of frozen ground conditions suitable for winter harvest has been shortened by 2 to 3 weeks in the past 70 years, and the contraction of winter snow cover and frozen ground conditions has increased seasonal restrictions on forest operations in these areas. The timing of suitable conditions for forestry operations has become shorter and more variable. Warming winters already have economic impacts on the forest industry. Populations of the emerald ash borer, a destructive invasive insect pest that attacks native ash trees, will increase due to warming winters in the region. Mortality of black ash trees, which are important for traditional basket-making for many tribes, is likely as winter temperatures continue to rise. Many tree species on which tribes depend for their culture and livelihoods-paper birch, northern white cedar, and quaking aspen, for example-are highly vulnerable to temperature increases. The arrival and spread of these beetles has prompted many states and provinces to set up EAB programs to protect their ash trees and the ecosystems that depend upon them.Ĭhanging climate conditions cause both cultural and economic impacts in the Midwest, and it’s very likely these impacts will worsen in the future. Discovered in Michigan in 2002, this invasive species is highly destructive to North American ash trees. The emerald ash borer (EAB), a species native to Asia, apparently arrived in North America in ash wood used for shipping purposes. With projected shifts in forest composition in the central hardwood region (southern Missouri, Illinois, Indiana, and Ohio) by the end of the century under a higher emissions scenario, substantial declines in wildlife habitat and the economic value of timber (a projected decline of up to $788 billion in 2015 dollars) may be expected by the end of the century. However, the fragmentation of the forests and the flatness of the terrain may limit the ability of particular species to shift to future suitable habitats. Changes in climate and other stressors will likely result in changes in forest types and composition as tree species at the northern limits of their ranges decline and southern species experience increasingly suitable habitat. Forests with lower tree diversity are more susceptible to widespread mortality and declines in productivity. Reduced diversity results in an increased risk to the negative effects of climate change, given the reduction in the number of tree species and age classes that are resistant to biological stressors. Impacts from human activities such as logging, fire suppression, and agricultural expansion have lowered the diversity of the Midwest’s forests. ![]() Overall, the increasing stress on trees from rising temperatures, drought, and frost damage raises the susceptibility of individual trees to the negative impacts from invasive plants, insect pests, and disease agents. The negative effects of insect pests and tree pathogens are anticipated to intensify as winters warm, increasing winter survival of pests and allowing them to expand into new regions. Warming winters will reduce snowpack that acts to insulate soil from freezing temperatures, increasing frost damage to shallow tree roots and reducing tree regeneration. Rising growing-season temperatures will increase the frequency of drought stress from drier soils and air (see the figure), and will likely result in reduced tree growth and widespread tree mortality.Īn increase in the mortality of younger trees, which are particularly sensitive to drought, may result in a shift in the composition and structure of Midwest forests. (b, c) The maps show the percent change in the moisture deficit of the air based on the projected maximum 5-day VPD by the late 21st century (2070–2099) for (b) lower and (c) higher emission scenarios. (a) Cooler air can maintain less water as vapor, putting less demand for moisture on plants, while warmer air can maintain more water as vapor, putting more demand for moisture on plants. Increased VPD has a drying effect on plants and soils, as moisture transpires (from plants) and evaporates (from soil) into the air. VPD is the difference between how much moisture is in the air and the amount of moisture in the air at saturation (at 100% relative humidity). As air temperature increases in a warming climate, vapor pressure deficit (VPD) is projected to increase. ![]()
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