Ungulate herbivory poses global challenges to forest regeneration. Deer, in combination with other biotic and abiotic factors, threaten to shift forest composition away from palatable hardwoods, such as oaks (Quercus spp.), and cause regeneration failure in some cases. Many studies have assessed methods to reduce or manage browse, but comprehensive analyses of the relative effectiveness of these techniques among published experiments are lacking. We synthesized the literature describing the results of methods to reduce deer browsing impacts, and assessed the effectiveness of deer browse management methods in controlling damage to hardwood forest regeneration. Specifically, we systematically analyzed results from 99 studies that used repellents, physical barriers, lethal population control, timber harvests, facilitation by neighboring plants, or fertilizer to affect browse, survival, or height growth of hardwood seedlings. Across studies, browse was reduced (mean effect size and confidence intervals) with the following: Fencing −3.17 (CI: −4.00–−1.31), shelters −1.28 (CI: −2.02–−0.67), cages −1.48 (CI: −3.14–−0.62), facilitation from neighboring plants −0.58 (CI: −1.11–−0.13), repellents −0.45 (CI: −0.56–−0.21), hunting −0.99 (CI: −1.51–−0.26). These methods each had positive effects on seedling height growth (except for repellents), and cages, timber harvests, fences, and mesh sleeves had positive effects on survival. Logging slash had no effect on browse incidence (−0.05, CI: −0.97–0.19). Fertilizer applied during seedling establishment increased browse (0.13, CI: 0.11–0.21), and did not affect height growth. We conclude that fences or other physical barriers best control for the effects of deer, but facilitation by surrounding vegetation, logging slash, hunting, habitat management through timber harvest, and certain repellents may also be moderately effective. Discrepancies between browse effectiveness and relative costs suggest that economic analyses should be developed to help to guide prescriptions for management.

Herbivory is a common forest regeneration challenge across ecosystems. While fencing effectively reduces animal browse damage, it can be impractical. Tree shelters are an alternative forest restoration tool to protect seedlings from herbivory that may also provide a favorable microclimate. Yet, regeneration responses to tree shelters often vary among tree species, environmental conditions, and shelter specifications. To restore the once dominant Quercus virginiana (live oak) and its associated conservation values to subtropical U.S. maritime forests, control of animal browsing is critical. We evaluated the effects of tube and mesh tree shelters to exclude animal browse, combined with the use of controlled-release fertilizer to promote Q. virginiana seedling growth. After two growing seasons, mean seedling survival was 83% for protected seedlings, either from tube or mesh shelters, compared to 68% with non-sheltered seedlings. Seedlings in solid-wall tube shelters had significantly less browse incidence compared to both seedlings in mesh shelters and non-sheltered seedlings. Seedlings in tube shelters had greater height and diameter, followed by mesh shelters, and lastly, the no shelter treatment. Fertilizer resulted in higher browsing incidence and greater seedling height and diameter after the first growing season only, with no shelter treatment interactions. Our findings illustrate the efficacy of tree shelters to improve early regeneration success of Q. virginiana and may have application to the restoration of other forest ecosystems.

Despite decades of research and practice restoring forests on surface coal mines, success is still variable, and failures often occur. To better understand how variation in site factors and management affects the success of restoration of coal mines, we conducted a survey of tree performance for mine sites in the Illinois Basin across Indiana, USA, reclaimed between 2008 and 2018. We explored the impacts of climate and soil conditions on the survival and growth of planted trees, as well as the cover of associated vegetation. Average overall survival (21%) was relatively low compared to typical unmined sites. Organic matter had one of the most consistent and largest effects on most oak species, with the highest performance between 3 and 5%. Soil phosphorus content was the most important factor determining whether a planting totally failed and affected the growth of White oak (Quercus alba) and Swamp white oak (Q. bicolor), though its effect on White oak was nonlinear. Rainfall in the year of planting had large positive effects on the survival and growth of Persimmon (Diospyros virginiana), and Black walnut (Juglans nigra) and temperature in the year of planting had large positive effects on the growth of Bur oak (Q. macrocarpa) and Persimmon. Planting a diverse mix of species is the best option both for approximating natural conditions, and for avoiding problems from the failure of individual species. While conditions vary, successful forest restoration on former coal mines can occur; this study reveals some of the most important factors affecting such success.