Native oak communities are at risk in Southwest Iowa for a variety of reasons. Urban development, invasive species, and agricultural production have eliminated much of the native prairies, savannas, and woodland ecosystems in the Loess Hills landform and surrounding areas. Blight, pests, and disease are also harming oak communities. Many of the oak communities that exist today have old-growth trees but lack middle-aged and young trees that are necessary for future viability. When people purchase oak trees at local nurseries, they are likely buying saplings grown from seed that is not native to the region. This decreases the chances of long-term success for the plant. This project aims to build capacity for utilizing local ecosystem native seed to establish new and enhance existing oak communities on both public and private lands in Southwest Iowa.
Oak communities have always been an important part of Iowa’s landscape. Native Americans relied on them for food, tools, and shelter. Many early settlements and homesteads were built near oak communities, as can be seen in community names like Red Oak and Oakland (originally called Big Grove). Oaks can help reduce soil erosion on steep slopes and streambanks, improving soil and water quality. They provide shade in many of our parks, public spaces, and backyards. When properly maintained, oak savannas can provide excellent land for grazing livestock. Oak is the official state tree of Iowa, yet it is surprisingly difficult to find an oak tree grown from locally-sourced seed in most local nurseries.
According to Iowa’s Forest Health Report, the state has lost an average of 4,500 acres of oak woodland each year since 1990. Oak woodlands could be completely eliminated from the state in 160 years if we do not act to save them. The Iowa Department of Natural Resources has data on native oak savannas and woodlands in Southwest Iowa, and this project will utilize that information to identify some of the highest-quality oak communities on public lands in the region. This data will also be used to identify public areas with the greatest decline in oak savannas and woodlands, which will help prioritize locations for tree plantings. The loss of oak trees has had and will continue to have significant detrimental impacts on the state’s economy. Many factors contribute to these losses. Bur oak blight, a fungal disease that harms and can even kill oaks, has been recorded in most Southwest Iowa counties. Bur oak blight is projected to cost Iowa’s wood products industry $19 million. Further, the community services lost due to oak blight will cost an estimated $600 million. Removal and replacement costs for dead and dying trees, decreased landscape values, and loss of wildlife habitat will cost many more millions of dollars across the state.
Oak wilt, a fungus that kills oak trees over a period of several weeks to a few years, is present in most Southwest Iowa counties. Oak wilt seems to proliferate during wet springs, which are predicted to become more common in Iowa’s future based on recent trends. Oak tatters, which can cause major damage over time, is also becoming more common across the state. While gypsy moths have not yet reached Southwest Iowa, they have reached other parts of the state and could someday impact the region’s oak woodlands and savannas. Buildings, roads, and other infrastructure often remove existing tree communities or hinder root development. Herbicide drift from farms and lawns is also harming oak trees and communities. Fires were an important part of the region’s ecology, but have been eliminated in most savannas and woodlands post-settlement. This has led to understory growth that harms the oak communities and reduces the chances for young oak trees to become established. Another potential risk, although not yet identified in Iowa, is Sudden Oak Death (phytophthora ramorum). Purchasing oaks from those areas and growing them in Iowa increases the risk of introducing this deadly invasive species to Midwest oak communities.
Oak trees provide habitat for many species of birds, insects, fungi, and mammals. Acorns are the most important food source for many animals in Iowa woodlands. Acorns are a preferred source of food for deer. When acorns are scarce, deer are more likely to consume crops, which can have devastating impacts for farmers. Forestry is also an important industry for the state’s economy, with oak being one of the public’s most preferred trees in Iowa. Quercus, the genus to which oaks belong, support at least 534 different species of butterflies and moths, which is more than any other genus. Awareness for pollinators has largely focused on specific bees and monarch butterflies. While those are absolutely important, oaks are being overlooked despite being crucial to a wider variety of pollinators. More information about oak trees' faunal associations can be found here. Information about pollinators can be found in Iowa DNR's publication "Iowa's Woodlands: Vital Habitat for Native Pollinators." By propagating acorns harvested from native oaks growing in local ecosystems, oak communities will thrive again in this region. Southwest Iowa features three distinct ecosystems: the Missouri Alluvial Plain, the Loess Hills, and the Southern Iowa Drift Plain. Acorns from any of these ecosystems may not grow well just a few miles away in one of the other ecosystems, so knowing the source of seed is crucial for long-term viability. Further, one species of oak known to grow in one county may not grow in the adjacent county. Verifying local provenance is crucial for sustaining and reestablishing oak communities. This project is important for Iowa because it would be a unique pilot project. While several organizations and many individuals are working to restore oak savannas and woodlands, we need an organized effort to grow new trees for oak savanna and woodland conservation, preservation, and restoration. The importance of oak trees for at-risk pollinators should also not be overlooked.
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