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Key messageRed cedar chlorophyll fluorescence remains high during the nongrowing season, while transpiration is reduced.Evergreen trees retain their leaves during the winter and thus can photosynthesize when conditions permit. Eastern red cedar (Juniperus virginiana) is widely distributed in the eastern USA and is known to transpire and photosynthesize outside of the growing season. However, most recent work has been done in the Great Plains, which red cedar has recently invaded, while little work has been done in its original range. I hypothesized that red cedar would behave like other conifers from summer drought-free areas and show reduced chlorophyll fluorescence and transpiration during the winter. Four red cedar trees at a site near the Ohio River in Kentucky were equipped with Granier sap flow probes, while solar irradiance, temperature, relative humidity, and soil volumetric water content (VWC) were measured at the site. Dark chlorophyll fluorescence (Fv/Fm) was measured on northern and southern aspects on an approximately weekly basis from early 2019 through mid 2021. High values of Fv/Fm were measured in both growing (April-September) and nongrowing (October-March) seasons; median values in the nongrowing season were 94% of those in the growing season, which did not support my hypothesis. Fv/Fm data were fit to a Michaelis–Menten curve that used minimum temperature of the previous two nights, aspect, and maximum irradiance on the day of measurement taken before fluorescence was measured. Sap flow was explained by maximum daily temperature, vapor pressure deficit (VPD), mean daily irradiance, and VWC. Sap flow in the nongrowing season was 74% of that seen in the growing season, due to lower values of temperature, VPD, and irradiance, supporting my hypothesis. Thus, red cedar remains physiologically active during the nongrowing season. However, it does not appear to behave like other conifers from summer drought-free areas.

Amur honeysuckle (Lonicera maackii) is a widespread invasive species in North America with extensive effects on native ecosystems. Since 2012, there have been extensive outbreaks of the native leaf fungal pathogen, honeysuckle leaf blight (Insolibasidium deformans), on L. maackii. This pathogen infects leaves in the late spring/early summer and eventually kills the leaves. Our objective was to describe patterns of blight occurrence on L. maackii growing in both the forest understory and in the open in northern Kentucky, USA. Smaller shrubs had a larger fraction of blighted leaves, because they allocated more production to long shoots, which are more susceptible to leaf blight. Overall, blight occurrence was as high as 8% on the smallest shrubs, though it was an order of magnitude lower on the largest shrubs sampled. Leaf blight appears to be an emerging pathogen that fits the Pathogen Accumulation Hypothesis. We developed a growth model that suggested small (< 5 cm basal diameter) open shrubs would be most affected by blight. Thus, future work should focus on comparison of the survival and growth of small infected versus uninfected L. maackii plants, as they appear to be most affected by the leaf blight.

Amur honeysuckle (Lonicera maackii (Rupr.) Herder) is recognized as one of the most important invasive species in the Ohio River Valley. Since 2012, outbreaks of the native pathogen honeysuckle leaf blight in the region have been observed, coincident with the report of high levels of L. maackii dieback in an open-grown stand in northern Kentucky. The purpose of this study was to quantify the extent of dieback in the area and to determine whether dieback was also present in stands growing under forest canopies (forest-understory). Data were collected from plots placed along transects for eight open-grown and six forest-understory sites in northern Kentucky and nearby southwestern Ohio in 2014–2016; diameters at stump height (25 cm) of all live and dead woody stems were measured in the plots. For L. maackii in open-grown stands, 30% and 23% of stem density and basal area, respectively, were dead, which was higher than that seen for associated shrubs and small trees; it was also higher than that reported in the 1980s for L. maackii in open-grown stands in the region. Mortality in the larger-size classes was higher than that seen in the 1980s. By contrast, stem mortality of L. maackii in forest-understory stands varied little from that seen in the 1980s. Basal area mortality was similar to associated species. The possible role of leaf blight in the decline of open-grown L. maackii requires further investigation.

Callery pear (Pyrus calleryana Decne.), a native of eastern Asia, has recently emerged as an important woody invader in much of the eastern United States. Little is known about its ecology in its new range. Its shade tolerance may be an important indicator of areas it is likely to invade. In this study, allometric equations were first developed to predict aboveground biomass components, including wood, branches, bark, leaves, and fruit, from diameter at stump height (dsh; 25 cm), by destructively harvesting 13 trees, ranging from 0.1 to 19.3 cm dsh. Then, a total of 23 wild-grown stands in the northern Kentucky/southwestern Ohio region were surveyed, with diameters of all woody stems sampled. Pyrus calleryana density, basal area, aboveground biomass, stand density index, size distribution inequality, and importance value were calculated for each site. Two-factor Weibull distributions were fit to diameter distributions. Allometric equations provided good fits for total aboveground biomass as well as individual components. Aboveground biomass levels fell below mean levels of native forest stands found in the United States. Stand density indices yielded values typical of shade-intolerant or midtolerant species. Stands with smaller trees generally had steeply declining monotonic diameter distributions, while stands with larger trees trended toward positively skewed monotonic distributions. These findings are consistent with a species that is either shade-intolerant or midtolerant. Thus, while this species is expected to invade open or disturbed areas, it is not expected to be an important invader under forest canopies. However, its extended deciduous habit is one shared by other understory woody invaders, and so this may allow it to survive under forest canopies.

Lonicera maackii (Rupr.) Herder (Amur honeysuckle) is one of the most important invasive plants in the Ohio Valley. Because of its phenology and dense canopy, L. maackii can exclude native herbs and interfere with regeneration of woody plants. In 2005, in a county park in southwest Ohio, I established modified Whittaker plots in four stands with a gradient of L. maackii cover ranging from 24 yr old to 40 yr old. The L. maackii canopies were removed by herbicides in fall 2005. Plant cover was monitored from 2005 to 2013. After 8 yr, there was an increase in species richness and herbaceous cover at all sites. Herbaceous species turnover was generally greater at sites with greater initial L. maackii cover. All of the most-common herbaceous species increased or maintained their coverage; most of the species that increased were those that bloom in late spring or summer. The abundances of other invasive species also increased, including Alliaria petiolata (M. Bieb.) Cavara & Grande (garlic mustard). However, A. petiolata abundance peaked 2–6 yr after L. maackii removal, suggesting that this increase, frequently seen after L. maackii removal, may be transitory. Previous studies have not shown such a decline after an initial increase in A. petiolata, but few studies have extended over this length of time. Ash (Fraxinus L.) decline caused by the emerald ash borer may now be affecting the recovery of these stands.

Amur honeysuckle (Lonicera maackii (Rupr.) Herder) is recognized as one of the most important invasive species in the Ohio River Valley. Since 2012, outbreaks of the native pathogen honeysuckle leaf blight in the region have been observed, coincident with the report of high levels of L. maackii dieback in an open-grown stand in northern Kentucky. The purpose of this study was to quantify the extent of dieback in the area and to determine whether dieback was also present in stands growing under forest canopies (forest-understory). Data were collected from plots placed along transects for eight open-grown and six forest-understory sites in northern Kentucky and nearby southwestern Ohio in 2014–2016; diameters at stump height (25 cm) of all live and dead woody stems were measured in the plots. For L. maackii in open-grown stands, 30% and 23% of stem density and basal area, respectively, were dead, which was higher than that seen for associated shrubs and small trees; it was also higher than that reported in the 1980s for L. maackii in open-grown stands in the region. Mortality in the larger-size classes was higher than that seen in the 1980s. By contrast, stem mortality of L. maackii in forest-understory stands varied little from that seen in the 1980s. Basal area mortality was similar to associated species. The possible role of leaf blight in the decline of open-grown L. maackii requires further investigation.

Despite their important ecosystem services, most wetlands in Kentucky and the surrounding region have been lost. Many restoration attempts have occurred, but the success of seeding or planting, which is often done after restoration, is unclear. To our knowledge, seeding success relative to other propagule inputs has never been quantified. We measured the restoration success of a four-year-old emergent open-canopy wetland, with seven adjacent ponds near the banks of the Ohio River in Kentucky. Potential restoration plant origins include (a) from the seedbank and surrounding area, (b) a native seed mix designed for upland and wetland restorations, and (c) from the onsite prerestoration wetland. We tested the hypotheses that elevation and distance from an established wetland pond are driving factors to establish species that dominate the wetland vegetative cover. Plant cover and relative elevation were determined in 78 1-m² plots. Although most species (73%) came either from seedbank or offsite sources, the remainder appear to have come from seeding (14–16%) and the prerestoration wetland (11–14%), and the latter two sources accounted for almost 50% of the total cover at the site. Ordination supported the hypotheses that distance from the prerestoration pond and relative elevation were the two most important factors determining patterns of plant cover. Despite its modest contribution to plant diversity, the prerestoration pond had an important effect on plant patterns. While the site falls into Kentucky Wetland Rapid Assessment (KY-WRAM) Category 1 (most disturbed), prevalence index (PI) scores, which are based on species wetland classifications, appear to be similar to or higher than those of other created wetlands in the United States.

Despite their important ecosystem services, most wetlands in Kentucky and the surrounding region have been lost. Many restoration attempts have occurred, but the success of seeding or planting, which is often done after restoration, is unclear. To our knowledge, seeding success relative to other propagule inputs has never been quantified. We measured the restoration success of a four-year-old emergent open-canopy wetland, with seven adjacent ponds near the banks of the Ohio River in Kentucky. Potential restoration plant origins include (a) from the seedbank and surrounding area, (b) a native seed mix designed for upland and wetland restorations, and (c) from the onsite prerestoration wetland. We tested the hypotheses that elevation and distance from an established wetland pond are driving factors to establish species that dominate the wetland vegetative cover. Plant cover and relative elevation were determined in 78 1-m2 plots. Although most species (73%) came either from seedbank or offsite sources, the remainder appear to have come from seeding (14–16%) and the prerestoration wetland (11–14%), and the latter two sources accounted for almost 50% of the total cover at the site. Ordination supported the hypotheses that distance from the prerestoration pond and relative elevation were the two most important factors determining patterns of plant cover. Despite its modest contribution to plant diversity, the prerestoration pond had an important effect on plant patterns. While the site falls into Kentucky Wetland Rapid Assessment (KY-WRAM) Category 1 (most disturbed), prevalence index (PI) scores, which are based on species wetland classifications, appear to be similar to or higher than those of other created wetlands in the United States.

The invasive shrub, Lonicera maackii, is known to change forest ecosystem communities and functions; however, few have studied the potential for this prolific invader to return after forest restoration. We studied the forest understory, canopy, seed bank, and incoming L. maackii seed rain in a riparian urban forest five to nine years after L. maackii removal and restoration efforts. We found the restored areas maintained a native canopy, but by nine years post-management efforts, L. maackii was becoming more important along multiple transects due to many small individual seedlings. The restored areas had greater herbaceous cover and species richness when compared to the control area (L. maackii-dominated). Lonicera maackii was not common in the seed bank during the study but was more prevalent in the seed rain of the restored forest with a tree canopy than in the restored open field without a tree canopy. While our results support the premise that removing L. maackii returns the community to a more native state, the study also shows that the native state would not last without additional minor intervention. Monitoring beyond ten years post-removal will be key to telling the whole reinvasion story, but management efforts every five to ten years could suffice to keep a restored forest dominated by native species.

Invasive shrubs can increase ecosystem transpiration and potentially affect hydrology in forested ecosystems. We examined two adjacent sites in a wetland forest in northern Kentucky, USA. One site contained little Lonicera maackii (Amur honeysuckle), while the other contained considerably more. Using Granier (thermal dissipation) and heat balance probes, transpiration was determined for trees, vines and shrubs at the two sites. Tree and vine transpiration in 2009 was usually 1–2 mm day −1 , typical of that seen in humid temperate forests. Additional transpiration from L. maackii was roughly proportional to its basal area, and it totaled 1.0% of tree and vine transpiration from the site with less L. maackii cover and 6.0% from the site with considerable cover. This additional transpiration amounts to roughly 10% of stream flow draining the study area. As L. maackii basal areas at these sites are at the lower end of that seen in other invaded forests in the region, regional impacts on transpiration and hydrology may be larger than those reported here. We expect L. maackii to shorten the lives of ephemeral ponds and streams in wetlands and cause adverse impacts on the organisms, such as amphibians, that require these aquatic environments to complete their life cycle.