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Saginaw Forest in Ann Arbor, Michigan, includes the second-oldest eastern white pine plantation in the United States, with pioneering thinning experiments among the oldest in the country. With no additional silvicultural treatments occurring since at least the 1950s, we report on the current condition of four planting lots near their century mark to provide silvicultural, cultural, and historical perspectives. Stand density and tree diameter in 2017 were similar across the four lots, all having a significant number of trees > 50 cm diameter at breast height. Tree ring widths suggest that diameter growth was responsive to thinning treatments that occurred before 1955. Today, management geared towards site preservation as a cultural and historical landmark, with an emphasis on intensive invasive species and hardwood ingrowth control and native tree species regeneration, are likely more appropriate than a focus on silviculture. Study Implications Saginaw Forest in Ann Arbor, Michigan contains the second-oldest eastern white pine plantation in the United States. It underwent pioneering forest thinning experiments that pre-dated similar experiments in the oldest eastern white pine plantation at the Biltmore Estate in Asheville, North Carolina. Silvicultural treatments have not occurred since the 1950s, but the effects of historical thinning treatments are evident today across four planting lots. We summarize the current conditions of this important forestry site, noting a serious threat by invasive species and hardwood ingrowth that should be targeted as a means of preserving this important cultural and historical landmark. [ABSTRACT FROM AUTHOR]

Since the introduction of the invasive bark beetle emerald ash borer ( Agrilus planipennis Fairmaire, EAB) to southeastern Michigan, most native ash ( Fraxinus spp.) species such as white ash ( F. americana L.), black ash ( F. nigra Marsh.), and green ash ( F. pensylvanica Marsh. ) have suffered mortality rates exceeding 99% after infestation in mixed stands. EAB-caused mortality has reduced or eliminated ash seed sources, resulting in a depleted seed bank and a reduced potential for regeneration that has led many researchers to predict a grim future for ash in North America. Blue ash ( F. quadrangulata Michx.) is thought to be the most EAB-resistant of all North American ash species with observed mortality rates between 30% and 40%, but few data exist describing blue ash regeneration dynamics in the presence of EAB. We sampled blue ash-dominated stands at six different sites in southeastern Michigan, nearest the EAB introduction point. White ash stands at the same six sites were also sampled as the reference condition for ash in the presence of established EAB. Overstory mortality for blue ash ranged between 7 and 32% and was significantly lower than white ash across all sites. Post-EAB overstory blue ash was on average significantly older and larger than white ash across all sites and maintained a higher frequency of healthier crowns. Blue ash regeneration densities were found to be abundant at all sizes within all stands. New seedlings (<3 yrs old) were significantly more abundant for blue ash than white ash across all sites, suggesting that blue ash has not experienced the same seed bank depletion as white ash. Blue ash seedling growth rates were greater than or equal to associated non-ash tree species at all size classes and at all sites, and equal to white ash seedling growth rates at the majority of sites and size classes. Our results suggest that blue ash is currently maintaining a relatively healthy and dominant position in the canopy of several forests in southeastern Michigan, and that blue ash is still regenerating in a capacity that shows a high probability of canopy self-replacement and thus persistence in the presence of EAB. [ABSTRACT FROM AUTHOR]

Stand-replacing fires are part of the natural disturbance regime that maintain jack pine ( Pinus banksiana Lamb.) forests of northern Lower Michigan. Currently, the occurrence and extent of wildfire is much reduced relative to the past and young jack pine plantations specifically managed for Kirtland’s warbler ( Setophaga kirtlandii Baird) are a prominent feature on the landscape. Stringers, or patches of residual pre-fire forest, are a unique feature left behind after wildfires which are not often accounted for in plantation management. In this study, we examined the ecological value of stringers from an avian biodiversity perspective by comparing bird assemblages found within stringers to those in the surrounding forest (non-stringers). Our objective was to answer two research questions: (1) do stringers have unique bird communities relative to the surrounding vegetation (forest or plantation)?; and (2) how much of the variation in bird communities can be explained by differences in vegetation structure and composition between stringers and non-stringers? We conducted breeding and non-breeding season point counts and used abundance data to compare bird species found within stringers and non-stringers at seven sites grouped by time since disturbance. Species richness was significantly higher ( P = 0.01) in the stringers when the non-stringers were 30–40 years old, with 32 species discovered in the stringers and 29 species in the non-stringers. During the breeding season, bird assemblages differed between stringers and non-stringers when the non-stringers were <12 years old (multi-response permutation procedures; T = −10.11, A = 0.07, P = <0.00), but no differences were observed when non-stringers were 30–40 years old or >40 years old. Non-breeding bird communities differed between stringers and non-stringers only when the non-stringer was a recently planted (<5 years old) plantation ( T = −2.15, A = 0.09, P = 0.02). Differences in bird assemblages appear to be driven by the vegetation structure of stringers and non-stringers where fires were recent, but increasing similarity in vegetation structure occurs with time since fire; over time the importance of stringers for avian biodiversity is reduced. Our results suggest that stringers are important for bird communities, especially in recently disturbed areas, and that these biological legacies should be considered where jack pine management attempts to emulate natural patterns and processes. [ABSTRACT FROM AUTHOR]

Prescribed fire is an increasingly common and effective management tool for ecological restoration of wetlands in the US Midwest. Prescribed fire is reported to have adverse effects on sensitive wetland fauna such as reptiles and amphibians, but surprisingly few empirical data are available to support management recommendations meant to protect herpe-tofauna from prescribed burning. We examined the effects of prescribed fires one day and one month after burning in eight wetlands across two wetland types in southeastern Michigan using abundance, species richness, and diversity of herpetofauna as metrics. Most amphibian communities returned to pre-bum levels of the three metrics by one month after the burn; reptile communities appeared to be more negatively affected by prescribed fire although sample sizes were extremely low. Response of individual species to burning was more variable; two previously detected amphibians and four previously detected reptiles were not detected by the end of the project, suggesting that some herpetofauna may respond negatively to fire while the most common species are unaffected. Only one individual of the 126 herpetofauna located in this study apparently experienced direct mortality after fire. We noted differences in species richness and diversity between wetland types that were probably attributable to differences in these metrics prior to burning. Although in some cases amphibian communities experienced few or only short-lived negative impacts of fire, we caution that fire effects are likely to be species-specific, such that prescribed burns should always be planned thoughtfully from this perspective. [ABSTRACT FROM AUTHOR]

Human–wildlife interactions in urban areas are widely reported by ecologists to be the result of human encroachment on wildlife habitat. Highly mobile species, however, have been documented by both wildlife biologists and casual observers to occupy areas heavily populated by humans. Range expansion and population growth of coyotes (Canis latrans) has led to their increased presence in metropolitan Detroit, Michigan, where poor economic conditions over the last several decades have resulted in the reversion of numerous recreational areas and abandoned parcels to more wooded or vegetated conditions that have provided potential wildlife habitat. We performed an extensive survey for coyote evidence (i.e., carcasses, den sites, scats, sightings, or tracks) across metropolitan Detroit to examine distribution across both the general region and specific land cover types. We found 58% of all coyote evidence on unpaved trails, paths, and unimproved roads within edge habitats (e.g., grassland adjacent to urban non-vegetative land cover), with den sites and tracks the only types of evidence found strictly in interior habitats. Land cover around evidence points included more wooded land cover than expected in suburban areas, suggesting the importance of tree cover for coyote occupancy, and more open space and wooded land cover than expected in urban areas, highlighting the coyotes' avoidance of heavily populated areas. We speculate that habitat characterized by tree cover has likely never been limiting within metropolitan Detroit, and that reoccupation of southeastern Michigan by coyotes is more likely a consequence of expanding coyote populations outside of suburban and urban areas rather than newly available habitat resulting from land cover change. [ABSTRACT FROM AUTHOR]

Abstract: On the dry, flat, jack pine (Pinus banksiana Lamb.)-dominated ecosystems of the northern Lake States and eastern Canada, wildfire behavior often produces narrow, remnant strips of unburned trees that provide heterogeneity on a landscape historically shaped by stand-replacing wildfires. We used landscape metrics to analyze a chronosequence of aerial imagery to examine these “stringers” of mature trees within historical wildfires in northern Lower Michigan. Our major objective was to describe the natural range of variability of stringer patterns and their persistence and change during the fire-free interval. Field studies were then used to examine stringer composition and structural variability. Stringers were found to occur in all fires >1000ha, in about one-third of wildfires >80ha, but never in fires <80ha, likely because of the lack of fire intensity on smaller fires that is necessary for stringers to be formed. Stringers were typically composed of many small, well-aggregated patches that represented 3–14% of the area within the burn perimeter, and stringer formation was relatively independent of pre-fire forest structure or composition. Stringer patterns changed mostly in the first decade after the fire that created them and then stabilized. Major changes that occurred in stringer patterns after this period were most often due to human activities, highlighting their natural persistence through the fire-free interval. The historical persistence and importance of these features also highlights their importance on modern fire-prone landscapes, particularly in northern Lower Michigan where a high proportion of land management is focused on jack pine plantations for breeding habitat for Kirtland’s warbler (Dendroica kirtlandii Baird), an endangered species. [Copyright &y& Elsevier]

Abstract: The emerald ash borer (EAB) has killed millions of ash trees in Michigan and at least fourteen other states since its first detection near its introduction point in metropolitan Detroit in 2002. Despite overstory ash mortality near 100% in many areas, ash seedling and saplings remain unaffected and provide the potential for ash re-establishment into the canopy of deciduous forests of the region. We examined the potential for ash re-establishment in areas of heavy mortality by measuring the status and change of ash regeneration at 45 sites across southeastern Lower Michigan in 2007 and 2009. Ash regeneration was found to be abundant in all forest types, particularly in the smallest height classes, though it was more abundant in ash species of upland forests compared to those of lowland forests. New seedlings 1–2 years old were less common than other regeneration size classes, and declined substantially between 2007 and 2009, suggesting a depletion of the ash seed bank in these forests. Regeneration density was not explained well by the presence of overstory ash prior to EAB introduction, suggesting that competitive interaction with other tree species in higher canopy strata is an important driver of ash regeneration density. Regeneration is sufficient to replenish overstory ash to pre-EAB levels in upland forests, though ecological changes caused by overstory ash mortality in lowland areas may affect local hydrology in a way that reduces opportunities for tree regeneration. Despite abundant ash regeneration, it remains unclear whether ash will recover to the overstory of forests in southeastern Michigan because of uncertainties in the future dynamics of EAB in the region. [ABSTRACT FROM AUTHOR]

Presents a landscape ecosystem approach to identify two adjacent landform-level ecosystems located at different elevations within the area burned by the 1975 Bald Hill fire in Crawford County, Michigan. Consideration of the Kirtland's warbler, Dendroica kirtlandii Baird, an endangered songbird that nests in northern Lower Michigan in ecosystems dominated by young jack pine; Findings that jack pines in the high-elevation landform exhibited faster growth and were colonized first by the warbler; Status of physical site factors as well as vegetative characteristics.