This book is a printed edition of the Special Issue "Understanding and Managing Emerald Ash Borer Impacts on Ash Forests" that was published in Forests

The emerald ash borer (EAB) is rapidly spreading throughout Eastern North America and devastating ecosystems where ash is a component tree. This rapid and sustained loss of ash trees has already resulted in ecological impacts on both terrestrial and aquatic ecosystems and is projected to be even more severe as EAB invades ash dominated wetlands of the western Great Lakes region. We propose a Special Issue that will address current research documenting ecological impacts of EAB in forest ecosystems, as well as management approaches to mitigate those impacts. Prospective authors are invited to contribute original researches to this Special Issue of Forests. Topics may include, but are not limited to: Managements of ash forests and potential replacements, nutrient and vegetation dynamics, greenhouse gas emissions and carbon sequestration and cycling, hydrologic impacts, and pre or post-infestation silvicultural approaches or management strategies.

The introduction of exotic species is the inevitable consequence of an expanding global society that relies heavily on international trade of goods and services. These introduced species have negative effects on biodiversity and disrupt native communities. In fact, the spread of non-native species is the second greatest threat to the loss of biodiversity next to habitat destruction. The emerald ash borer (EAB), Agrilus planipennis Fairmaire (Buprestidae), is a recent example of an exotic forest pest species. EAB completes its life cycle on ash trees (Fraxinus spp.) including larvae feeding on cambium tissue which interferes with water and nutrient translocation. Once ash trees become infested with EAB, mortality is>99%. This dissertation was initiated after EAB was discovered and attempts to understand how EAB affects long-term forest community dynamics in order to provide practical applied conservation strategies. These research projects are designed to identify the ecological impacts of EAB and to determine long-term community changes to native deciduous forests. The research objectives are: (1) to identify consequences of EAB eradication efforts, (2) to determine altered community composition under different disturbance intensities (tree removal management recommendations) and (3) to design effective ex situ conservation protocols for future ash tree preservation. EAB causes a disturbance to native forest by creating large light gaps through ash tree dieback; yet, EAB eradication efforts magnified the scale of disturbance through time and space which facilitated the establishment of invasive plant species. The tracked vehicles used during eradication also caused significant soil compaction. Management efforts applied to EAB-infested forests should prioritize appropriate tree removal techniques to minimize the disturbance to the surrounding community. Ash stands in close proximity to roads or edges, or near established invasive populations may benefit from proactive removal of invasive species. This research contributes to ash conservation efforts by providing a guideline for ex situ collection methods. By understanding diversity and spatial genetic structure of green ash (Fraxinus pennsylvanica), a seed collection protocol has been constructed that optimizes the likelihood of capturing all alleles in a population while minimizing collection efforts. This cumulative research provides effective forest management recommendations and prioritizes ash conservation.

As non-native forest pests disperse across the United States, the emerald ash borer, Agrilus planipennis (EAB), has emerged as one of the most costly and destructive invaders. In response to EAB, forest management practices, including pre-salvage logging, "phloem reduction" (large ash removal), and strategies to improve future ash regeneration, have been implemented to meet economic, ecological, cultural, and safety objectives. Although many studies have quantified the impacts of EAB on mortality of ash trees (Fraxinus spp.), less is known about the short- and long-term ecological impacts of forest management in response to this pest. In summer 2020, we measured forest structure and composition at sites across New England that included white ash harvests motivated by the threat of EAB impacts. Management responses varied from selective ash removals to capture potential economic losses to group selection harvests designed to recruit new ash cohorts. Informed by our findings, we modeled three approaches to ash management under three potential future climate regimes, along with EAB and natural wind disturbance for a 100-year period in northern Bennington County, Vermont. This dual approach allowed us to examine both the immediate aftermath of forest management responses to EAB, and the future outcomes of these management practices on ash trees and their natural communities, in the context of other important drivers of forest dynamics such as climate change. In our observational study, we found a lower proportion of white ash basal area in harvested study sites compared to unharvested control sites. However, white ash regeneration at the seedling and sapling stages was higher in harvested than in unharvested plots. In addition, our modeling of ash management practices projected more white and black ash biomass present in 2120 forests when harvests and chemical treatments prioritizing ash retention and regeneration were implemented compared to typical current practices, and less ash biomass in 2120 following more aggressive salvage and pre-salvage harvests removing white ash. Climate also played a significant role in next-century forest composition, as more drastic climate projections compared to current conditions favored warmer-adapted species in the region. Our findings indicate that forest management practices that align with ash species' silvics, such as the greater light availability needed to successfully recruit new white ash cohorts, can bolster ash regeneration and perpetual presence in New England forests. Although EAB remains a significant threat, our work confirms the importance of implementing a variety of management approaches, supported by recent findings that ash survival and resistance to EAB is more prevalent, and more variable, than previously thought. This work will help inform future management decisions in response to this invasive pest that ensure long-term ecological and economic options are maintained on site.

This book was written by undergraduate students at The Ohio State University (OSU) who were enrolled in the class Introduction to Environmental Science. The chapters describe some of Earth's major environmental challenges and discuss ways that humans are using cutting-edge science and engineering to provide sustainable solutions to these problems. Topics are as diverse as the students, who represent virtually every department, school and college at OSU. The environmental issue that is described in each chapter is particularly important to the author, who hopes that their story will serve as inspiration to protect Earth for all life.