Browsing Damage Research Articles

Wildlife damage to forest stands in the context of climate change – a review of current knowledge in the Czech Republic

Abstract Wildlife damage to forests has become an increasingly serious problem in recent years, and its impact is exacerbated by ongoing climate change. Rising temperatures, prolonged droughts, uneven precipitation distribution, and other factors affect forest ecosystems, which, in turn, affect cloven-hoofed animal populations, their food preferences, and ultimately, the extent of damage they cause. Based on 133 references, this review article focuses on the relationships between wildlife damage and climate change and presents possible strategies to address this issue in the Czech Republic. Wildlife damage includes not just browsing and fraying in natural and artificial regeneration but also damage to trees from bark stripping and the lesser-known rooting of seedlings. Concerning tree species, browsing is most damaging to silver fir (Abies alba Mill.) and sycamore maple (Acer pseudoplatanus L.). The enticement to wildlife increases as the proportion of the tree species in the stand decreases. Browse damage is more severe at the edge of the stand. Bark stripping and secondary rot cause the most damage to the production quality of Norway spruce (Picea abies [L.] Karst.). Total wildlife damage increases with elevation. Combined with the progress of climate change, game-induced damage significantly restricts close-to-nature forest management practices and limits the use of adaptive measures in response to climate change. In addition, mixed forests with species that attract wildlife and the rapid increase in the number of clearings following bark beetle salvage logging significantly increase game pressure. This is primarily the result of the overpopulation of native and introduced game species and the considerable inconsistency between forest and hunting management practices, with the latter not respecting the principle of ecologically tolerable game damage.

Impact of salvage logging on short-term natural regeneration in montane forests of the Alps after large windthrow events

Wind disturbances are one of the main drivers of forest dynamics in Europe, shaping forest stands and modifying the ecosystem services provisioning. Salvage logging is often most common strategy adopted after a high-severity disturbance in managed stands. Understanding natural regeneration dynamics including their interaction with the logging operations, is crucial to understand how forests will be changing under a climate with increasing variability and to design adequate adaptive post-disturbance management strategies. In this study, we focused on 148 stands damaged by storm Vaia (2018). The aim was to analyze natural regeneration dynamics under different logging systems and to investigate influences of site characteristics and disturbance legacies on sapling growth and seedling emergence. The sampling protocol consisted of one transect per stand, perpendicular to one of the intact forest edges, and with a length of 80 m. Along the transect, we collected soil cover, natural seedling and sapling stem density, and deadwood quantity in four sample plots of 3 m radius each at distances of 0, 20, 40, and 80 meters from the edge (592 plots in total). Regeneration species composition was mainly driven by previous stand composition, with some exceptions depending on seed dispersal strategy. Distance from the edge significantly influenced seedlings and saplings occurrence in large gaps and affected the browsing damage percentage, together with deadwood presence. According to GLM’s models, distance from the edge, elevation, and logging methods influenced seedling establishment. At the same time, species characteristics, edge structure, deadwood and logging damages significantly influenced pre-storm seedlings and saplings presence and health. In conclusion site factors, disturbance legacies, and logging strategies are key points to consider in post-disturbance management for a fast forest recovery.

An economic analysis of management practices to mitigate butt rot and deer browse of planted western redcedar

We consider the economic feasibility of silviculture investments to reduce butt rot (through stump removal) and ungulate browse damage (stand establishment strategies), which are the most serious impacts to planted western redcedar (Thuja plicata Donn ex D. Don) stands in coastal British Columbia, Canada. We find mixed support for these investments, even if carbon sequestration benefits are included. We do find butt rot causes significant material damage to volumes, but such damage tends to occur well into the future of the stand diminishing the negative impact on stand value. As such, given the high costs of stump removal, and despite losses of high-quality logs, we find little support for stump removal except under very low discount rates (2%). Deer browse impacts are found to occur in the early stages of stand development, and projected stands should sufficiently recover volumes and value by harvest age. However, under positive carbon prices, because deer browse mitigation measures have an immediate impact on biomass accumulation in the early stages of stand development, we find some conditions for which low-cost deer browse mitigation options might be economically supported on forestlands. Finally, we found that increased planting of seedlings is likely a low-cost, financially attractive option under a broad set of conditions, even on sites without risk to damage, meaning a possible no-regrets strategy to mitigate damages from either deer browse or decay. The benefits of planting highlight the feasibility of using tree breeding to increase growth, resistance to deer, decay, and drought. The methods developed in the paper to evaluate the impact of both root rot and ungulate browsing could be applied to other ecosystems elsewhere.

Causes and consequences of large-scale windthrow on the development of fir-beech forests in the Dinaric mountains

We investigated several aspects of windthrow that are relevant to our understanding and management of forest ecosystems. As an example, we used an extreme event in December 2017, when the strongest storm in recent history occurred in the Slovenian Dinaric High Karst. We examined influential factors such as soil properties, wind speed, precipitation and ecological consequences for the affected forests. Soil properties were measured around standing and fallen silver fir trees at all three research sites. Tree species composition in the regeneration was observed on plots with chemical and acoustic ungulate deterrents and on control plots without deterrents. Economic estimates of yield loss due to damage were calculated at the national level. A model of the potential threat from windthrow was also developed based on data collected from windthrow events and meteorological data over the past 20 years. Our results indicate that soil depth and mineral fraction depth were similar at sites with and without damaged trees and were not the determining factors for tree toppling. Plots with acoustic deterrents showed the most effective regeneration development, the least decline in silver fir and the greatest increase in noble hardwood seedlings, while plots with chemical deterrents showed the least browsing damage. The estimated economic loss of €16.1 million is 6.6% less than the harvest under normal conditions. The economic loss was relatively low due to the nature of the storm, with the predominant type of damage being uprooted trees with no damaged trunks. The windthrow hazard model revealed that a large number of consecutive events with strong winds in each section weakened the stand, which was subsequently knocked down during the next extreme wind and rainfall event.

Future browsing damage in seedling stands according to projected forest resources and moose population density

Future browsing damage in seedling stands according to projected forest resources and moose population density

Rapid increase in sensitive indicator plants concurrent with deer management in an oak forest landscape

AbstractWildlife managers are implementing programs to reduce abundant populations of large herbivores, such as white‐tailed deer (Odocoileus virginianus) in eastern North America, with renewed research interest in understanding these programs' ecological effects. To examine plant community change following culling of white‐tailed deer in oak (Quercus spp.) forests in Ohio, USA, we measured browse severity on tree seedlings and cover of 43 deer‐sensitive, native indicator plant species across 20 years spanning pre‐ (2002–2015) and post‐ (2016–2021) deer culling periods. After culling halved deer abundance from 16.7 deer/km2 to 8.6 deer/km2, browse patterns on tree seedlings reversed from most seedlings exhibiting browse damage to most being undamaged. Cover of deer‐sensitive indicator plants increased 7‐fold in the 6 years after deer culling. Five of 6 indicator plant groups (e.g., Liliaceae) and 32 of 43 indicator species (74%) increased in cover after deer culling. Rhizomatous, clonally reproducing and early flowering (May–Jun) species were generally most responsive. The rapid increase in deer‐sensitive plants after deer culling in our study is among the fastest and largest reported among eastern North American studies. The plant community resilience observed in this study could partly relate to the relatively short duration (~10 yr) that deer populations were elevated before culling began, allowing persistence of local plant regeneration potential. Deer culling enabled a moderate deer population to coexist with a rising sensitive plant population.

Browsing Damage on Scots Pine: Direct and Indirect Effects of Landscape Characteristics, Moose and Deer Populations

Reducing browsing damages from cervids (Cervidae) on economically valuable tree species is a challenging task in many countries. Apart from cervid abundance, landscape characteristics, such as forest composition, land use, forage availability and climatic conditions, may affect the degree of browsing through both direct and indirect effects. A better understanding of basic mechanisms in this complex system is needed to design efficient and convincing management strategies. Focusing on Sweden as a case, which has been widely studied using regression analyses only, we applied path analysis to test the validity of a model on the indirect and direct links between landscape characteristics, cervid populations, and browsing damages on Scots pine (Pinus sylvestris). Our results validated the tested model in which moose (Alces alces) density and pine availability directly influence browsing damages. Increasing amounts of pine forests, preferred deciduous trees, and young forest had positive direct effects on moose densities and thereby indirectly contributed to increased browsing damages. The density of smaller deer species showed no direct effect on browsing damages on pine. Path analysis corroborated our attempt to disentangle direct and indirect potential causal drivers of browsing damages and shows that the choice of statistical method may alter the understanding of mechanistic driving forces.

Moss cover and browsing scores as sustainability indicators of mountain ungulate populations in Mediterranean environments

Here, we aimed to define ecological indicators of environmental change for monitoring the effect of a reintroduced species, the Iberian ibex (Capra pyrenaica), over the vegetation of a natural protected area with contrasting habitats. This species was reintroduced 30 years ago in the Sierra de Guadarrama National Park, Spain, and its population has since grown exponentially, reaching high densities in some areas. We tested the suitability of two complementary indicators: browsing damage on woody species and the percentage of moss cover loss on rocky outcrops. For this purpose, we used a mathematical approach to zone the natural protected area according to the historical presence of the species and established five different Iberian ibex pressure classes (Classes I–V). Our results showed a direct link between Iberian ibex pressure and vegetation status. Model predictions suggested 10% moss loss in the areas with low pressure (Class I) but 64% loss in the areas with high pressure (Class III), mostly due to ungulate trampling on rocks. Similarly, browsing damage increased with increasing pressure classes for different woody species. Low palatable plant species such as Pinus spp. showed little change in browsing damage for increasing ungulate pressure whereas more palatable plants (e.g., Erica arborea) showed significantly greater browsing damage variation across pressure classes (i.e., high sensitive to herbivory pressure). Both, moss cover on rocks and widely distributed palatable woody plants proved useful ecological indicators for monitoring ungulate populations in mountainous areas with a diverse array of habitats (e.g., rocky vs. woody). This methodology may help select the most suitable indicators for each type of ecosystem or dominant habitat in ungulate-dominated ecosystems.

Associational effects, landscape context, and plant height affect white‐tailed deer (Odocoileus virginianus) browse selectivity in oak woodlands

AbstractQuestionsLarge spatial variation in damage intensity is a pervasive, but poorly explained, feature of herbivore–plant interactions. To predict herbivore effects on plant communities, ecologists need greater understanding of the mechanisms and relative importance of processes driving variation in damage at the spatial scales of individual plant, plant community, and landscape. We ask: (1) what are the relative strengths of traits of individual plants versus landscape context in affecting white‐tailed deer (Odocoileus virginianus) browsing on saplings in oak woodlands; and (2) is browsing intensity on post oak (Quercus stellata) influenced by associational effects related to density or frequency of more‐selected or less‐selected species?LocationDry oak‐dominated woodlands, Kansas, USA.MethodsWe sampled deer browsing on saplings in three woodlands, each containing five transects, with 21 10‐m2 plots per transect. Transects ran from woodland–grassland edges into woodlands. In each plot, we identified saplings to species, measured variables in individual‐plant (height) and landscape contexts (distance from edge and proximity to deer trails), and quantified proportion of stems browsed per sapling.ResultsBrowsing intensity varied greatly among the 18 tree species encountered. Browsing increased with sapling height and decreased with distance from woodland edges. The effect size of distance from edge was twice that of sapling height, although both effect sizes were small. Browsing on post oaks increased with local frequency of saplings of more‐selected species.ConclusionsOur comparison of individual‐plant versus landscape context variables and our assessment of associational effects supports a substantial role for coarse‐scale foraging decisions in explaining browsing damage. However, sapling species identity was most influential. Associational susceptibility of a less‐selected species, post oak, near more‐selected neighbors is consistent with a mobile herbivore choosing between patches. The pre‐eminence of frequency of more‐selected species in mediating associational susceptibility may reflect decreased handling time in pure patches and/or attempts to balance nutrients.

Toward a Beech-Dominated Alternative Stable State in Dinaric Mixed Montane Forests: A Long-Term Study of the Pecka Old-Growth Forest

In the last century, a synchronous beech expansion has been observed for many mixed mountain forests in southeastern Europe. This change is associated with the interaction of various disturbances. We analyzed structural changes in the Pecka old-growth forest in Slovenia during the last century, using several inventories of the tree layer, regeneration, and site factors. Throughout the observation period, the density of silver fir in the regeneration layer and in the overstory steadily decreased. In 1893, silver fir accounted for about 60% of the growing stock, whereas in 2013 it accounted for less than 13%. This is likely because of silver fir’s decline in the canopy layer due to air pollution, successive windthrows, and overbrowsing. However, climate change may also have played an important role, as silver fir also declined in southeastern European old-growth forests where air pollution was less pronounced and ungulate densities were low. A gradual decline of silver fir in the overstory resulted in a decrease of overall tree density to 231 trees ha–1, while growing stock remained relatively high at 712 m3 ha–1. Median diffuse light at 1.3 m was 3.7% and regeneration density was 19,954 ha–1. Beech was dominant (94%), followed by silver fir (4%), and sycamore maple (2%). No silver fir seedlings larger than 0.2 m were recorded. Silver fir, sycamore maple, and beech regeneration showed 87, 76, and 45% browsing damage, respectively. Regression models indicated some evidence of niche partitioning between silver fir and beech. However, many processes may be masked by the silver fir’s avoidance strategy. Given current red deer densities, climate change, and existing forest structure, the Pecka old-growth forest will likely reach an alternative stable state dominated by beech in a few decades. This calls for immediate reduction of ungulate populations. Despite the interaction of multiple disturbances, the Pecka old-growth forest has maintained a relatively high overall growing stock, a favorable microclimate, and succession pathway with shade-tolerant beech. This indicates the intrinsic resilience of natural forests. The mechanisms discussed here can be applied to the future governance of old-growth and managed montane mixed forests.

Toward Identifying Alternatives to Fencing for Forest Restoration: Tube Shelters Outperform Mesh Shelters for Deer Browse Protection of Live Oak, Quercus virginiana

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.

Moth declines are most severe in broadleaf woodlands despite a net gain in habitat availability.

While agricultural intensification and habitat loss are cited as key drivers of moth decline, these alone cannot explain declines observed in UK woodlands – a habitat that has expanded in area since 1968.We quantified how moth communities changed across habitats and regions and determined how species traits interacted with habitat in predicting moth abundance change. We hypothesised that, in woodlands, species more vulnerable to shading and browsing by deer (species specialising on forbs, shrubs and shade‐intolerant plants) had declined more severely than other species, and that moth decline in woodlands was more severe at sites more susceptible to deer damage.We modelled abundance, biomass, species richness and diversity from 1968 to 2016 and explored how these interacted with habitat and region. We also modelled the interaction between habitat and two moth species traits: larval feeding guild and shade‐tolerance of hostplant.Moth declines were consistently highest in broadleaf woodland. Abundance, biomass, species richness and diversity declined significantly by −51%, −52%, −14% and −15% in woodlands, respectively, compared to national trends of −34%, −39%, −1% (non‐significant) and +10%. Declines were no greater in woodlands more susceptible to deer browsing damage. Traits based analysis found no evidence that shading and intensive browsing by deer explained moth declines in woodland.Moth decline was more severe in broadleaf woodlands than in intensively managed farmlands. We found no evidence that deer browsing or increased shading has driven these trends: the primary cause of the decline of moths in woodlands remains unclear.

Population density and plant availability interplay to shape browsing intensity by roe deer in a deciduous forest

Browsing damage in forests relies on a complex interaction between herbivore density and forest understory composition and relative availability. Although variation in the amount of browsed twigs is sometimes used to assess abundance of large herbivores, the potential confounding effect of resource availability on this relationship has not been investigated yet. To fill the gap, we measured how browsing intensity of the woody plants varied in response to changes in both roe deer (Capreolus capreolus) abundance and vegetation availability from an intensive long-term monitoring. We estimated plant availability and consumption by roe deer from a modified Aldous method throughout a 14 year-long period during which we experimentally manipulated population density. The functional response was strongly non-linear and density-dependent. When plant availability was low (<12.5%), browsing intensity strongly increased with plant availability with an increasing rate of roe deer density, whereas beyond this threshold, browsing intensity slightly increased with both plant availability and population density in an additive way. Thus, forest susceptibility to browsing increases with increasing competition for food, especially when plant availability is low. Moreover, the interplay between browsing intensity and population density at low plant availability prevents the use of browsing intensity to monitor roe deer abundance when plant availability is low. Our findings provide clear evidence that relying on key ecological concepts such as functional responses improves the accuracy of management tools when monitoring changes of the herbivore-plant system over time.

Survival and growth of Japanese cedar (Cryptomeria japonica) planted in tree shelters to prevent deer browsing: a case study in southwestern Japan

ABSTRACT Tree shelters are used in forestry to prevent large herbivores from browsing on young trees. Although tree shelters can generally prevent browsing damage while the young trees are within the tree shelters, they have been observed to fail in some cases. In this study, to clarify the protective capacity of tree shelters against damage due to deer browsing, the condition of tree shelters on planted Japanese cedar (Cryptomeria japonica) seedlings 2 to 7 years after installation was investigated at 42 sites in southwestern Japan where the density of sika deer (Cervus nippon) is high. The results showed that tree shelters failed for three reasons. Firstly, the shelter had collapsed or incline and could no longer protect the saplings within. Secondly, the saplings in the shelters died relatively shortly after they were planted. Thirdly, and possibly most importantly, the saplings are browsed upon by deer after they extended beyond the top of the shelter. Since there was no correlation between the damage rate and the number of years after planting, it is likely that the damage occurred immediately after the young trees protruded form the shelter. Shelters with a height of only 140 cm, which are widely used in Japan, may be too short to completely prevent herbivory damage by deer.

Status surveys of Helonias bullata (swamp pink) in New Jersey: Long-term declines from deer browse and hydrological change1

Systematic field surveys were conducted in 2010–13 for the threatened, globally rare plant species, Helonias bullata L. (swamp pink: Liliaceae) in New Jersey, which contains 60% of known populations. A total of 90 sites were visited, including 56% of extant populations, focusing on the highest quality, largest, and most geographically representative populations in the state in order to comprehensively assess the species' status. A complete census and threat assessment was conducted for each population, using standardized methods adopted during previous surveys in 1997–2001, and population trends were determined by comparing results between data sets. The results found declines in 83% of Helonias populations in the past 10 yr, including severe declines (> 67%) in 53% of populations, and another 26% experiencing declines of 20% or more. Analyses of past and present data sets found the primary cause of declines appeared to be herbivory by white-tailed deer (Odocoileus virginianus), which had not been previously regarded as a significant threat to the species, followed by hydrological changes caused by human development and/or water consumption. Browse damage to Helonias was directly observed in 84% of populations, with an average of 40% of Helonias clusters exhibiting recent damage at each site. Concern for observer bias was also explicitly addressed in the methods and analyses providing further confidence in the results. Implications for the conservation and recovery of Helonias are discussed, as well as the benefits and limitations of the standardized methods used for long-term studies of this and other rare plant species in the future.

Junipers enable heavily browsed rowan saplings to escape ungulates in boreal forest

Recent increases in ungulate herbivore populations have intensified browsing pressure in northern forest ecosystems. High browsing pressure affects recruitment into tree populations and saplings are among the most impacted and critical tree stages. This calls for research on factors that enhance sapling survival and promote recovery of herbivore preferred species. One understudied factor in ungulate dominated boreal forests is the ability of young trees to escape large herbivores by utilising “nurse plants”. First, we examined the impact of ungulate browsing on the abundance and size of rowan (Sorbus aucuparia), a functionally important tree species in an old-growth boreal pine forest, western Norway. The responses were compared between exclosures and ungulate-access plots over ten years (2001–2011) combined with investigations along a browsing intensity gradient (Exp. A). In a second experiment we investigated whether rowan saplings escape browsing and enhance growth and survival by growing within nurse plants. Consequently, we planted rowan saplings in ungulate browsing areas, inside and outside coniferous juniper (Juniper communis) bushes, and analysed the treatment effect on browsing, growth, and survival of rowan saplings across five years (2013–2018; Exp B). Excluding large herbivores resulted in a large increase in rowan saplings which were six times more abundant in exclosures (0.44 ind./m2) compared to ungulate-access plots (0.07 ind./m2) after ten years (Exp. A). The abundance of rowan saplings also decreased with higher browsing intensity. Moreover, the rowans in exclosures grew to almost twice the height of the ungulate-access rowans. The protected rowan saplings experienced significantly less browsing damage, and only 25% of the protected plants experienced heavy browsing or died after the first winter, compared to 70% of the unprotected plants (Exp. B). After five years, 50% more unprotected than protected plants experienced heavy browsing or mortality, and growth in protected plants was nearly 50% greater over the period. The negative impact of ungulate browsing on abundance and growth of rowans can be counteracted by positive plant-plant interactions. Rowan saplings growing within nurse plants showed significantly less browsing and better performance indicating high functional importance of the forest understorey. Forest managed with multi-layered and multi-species understoreys may therefore also be beneficial for tree recruitment in browsed boreal forest landscapes.

Large-scale spatial distribution of deer browsing damage to young tree plantations

The economic loss caused by herbivore browsing in forest plantations is a concerning problem in many areas around the world. Information on the spatial distribution of browsing damage is important for forest owners when selecting locations for new plantations, because planting trees in areas of high browsing pressure increases economic losses. Although it is difficult to survey browsing damage across large areas, sporadic sampling data on browsing damage are often collected by foresters, governments, and researchers. Thus, in this study, we applied a generalized additive model (GAM) for analysis of sporadic data to reveal large-scale spatial variation in deer (Cervus nippon) browsing damage. A map of browsing pressure produced by a GAM that used years after planting (plantation age) and location as independent factors showed a few areas of high browsing pressure. In addition, browsing damage increased with increasing plantation age, and plantation stands aged 2+ years showed more browsing damage. Areas with high browsing damage estimated based on plantation stands aged 2+ years generally coincided with areas of high deer abundance, with some exceptions. Thus, this model reflects large-scale browsing damage relatively well and will help forest owners to avoid locating new plantations in areas of high browsing pressure.

Effect of biofuel waste, urea, deer browsing, and vegetation control on Pinus banksiana seedling growth on a dry upland site in central Canada

Ash from biofuels and nitrogen fertilizer are increasingly being used as soil amendments. While this can increase tree growth, it can also increase mammalian grazing and competition with vegetation. We applied moderate amounts of ash (1.5 t·ha−1·year−1) and urea (74 kg N·ha−1·year−1) in each of 2 years to a well-drained site in southeastern Manitoba, planted with Pinus banksiana Lamb. Subplots received deer browsing and (or) vegetation control. The ash resulted in an increase in pH in the upper 15 cm of mineral soil from ∼5.7 to 6.6, and the urea created short-term spikes in soil inorganic nitrogen (NH4 and NO3) levels. Urea combined with ash significantly increased seedling relative growth rates in the first 2 years, with seedlings being largest with urea, with or without ash. However, by the fourth year, seedling growth and size did not differ between the amendments. Urea application increased browsing damage to 91%, but only when vegetation was mowed. Browsing guards resulted in seedlings having 1.6 times greater shoot mass by the end of the fourth growing season. These results suggest that on sandy soils in the dry region of central Canada, P. banksiana may get little benefit from ash applications.

Ungulate-adapted forestry shows promise for alleviating pine browsing damage

High densities of ungulates can increase human-wildlife conflicts. Where forestry is an important economy, intensive browsing can lead to browsing damage, resulting in volume losses, poor stand regeneration, and reduced timber quality. The forestry industry thus looks for practical, long-term measures to mitigate browsing damage. We tested the effect of two mitigation measures on moose (Alces alces) browsing behaviour and damage to Scots pine (Pinus sylvetris): (1) ungulate-adapted slash piles (i.e., palatable species only) created during felling to increase short-term food availability and (2) intensified soil scarification to increase long-term food availability (collectively, ‘ungulate-adapted forestry’). Our study occurred in southern Norway where we established fixed vegetation and moose faecal pellet plots at varying distances from conventional and ungulate-adapted slash piles and scarified stands. We evaluated the effects of ungulate-adapted slash piles and intensified scarification on the density of undamaged Scots pine, moose bite diameters, browsing pressure, and moose faecal pellet density. To assess the effect of spatial scale, we created 250 m, 500 m, and 1000-m radius buffers centered on each plot. We found that ungulate-adapted logging near our plots increased the density of undamaged pines, as compared to no and conventional logging. We found that logging in general led to smaller bite diameters. We also found that plots near conventional logging had higher browsing pressure, whereas browsing pressure near ungulate-adapted logging was similar to unlogged stands. For scarification, density of undamaged pine increased when the ungulate-adapted stand aged whereas undamaged pine decreased as conventional scarification stands aged. Browsing pressure showed a response at the smallest spatial scale only for ungulate-adapted scarification. Peak moose habitat use near conventional and ungulate-adapted scarified stands differed by stand age and distance from scarification. The overall effects of ungulate-adapted forestry were most pronounced at the smallest spatial scale (250 m). Our results support ‘ungulate-adapted’ forestry as a practical solution to mitigate browsing damage but uncertainty in some of our estimates suggest further research on the area treated is needed.

Matching species traits and microsites improves regeneration in mixed oak woodlands

AbstractQuestionWorldwide, mixed oak woodlands regenerate poorly due to different anthropogenic impacts. Our question is whether spatial distribution (regeneration microsite) of oak recruits is determined by different biotic and abiotic stress agents and whether recruits of co‐occurring oak species may respond differently to each source of stress.LocationMediterranean California mixed oak woodlands.MethodsWe recorded the main regeneration microsites of four co‐occurring oak species (Quercus lobata, Q. douglasii, Q. kelloggii and Q. agrifolia) in 25 belt transects in a nature reserve and identified the main stress agent for each species and microsite. We also analyzed their response to stress through physiological parameters (chlorophyll, flavonol, anthocyanin and nitrogen).ResultsQ. agrifolia and Q. lobata seedlings mostly established under shrubs and trees, respectively. The other species did not have a prime regeneration microsite. Biotic stress occurred more frequently than abiotic (drought) stress for all species. Regarding biotic sources of stress, the deciduous Q. lobata, Q. douglasii and Q. kellogii showed high browsing damage; insect damage was light and occurred mostly in the evergreen Q. agrifolia whereas fungal damage was significantly lower in Q. douglasii. Physiologically, all oak species responded similarly to stress agents although Q. douglasii and Q. kelloggii showed higher chlorophyll content than Q. agrifolia and Q. lobata, which might be related to differences in resilience.ConclusionsDeciduous oaks are particularly vulnerable to overgrazing whereas the evergreen Q. agrifolia seems more affected by fungal and insect damage. Management aimed at the co‐existence of deciduous and evergreen oaks should consider the enhancement of microsites that best ameliorate the impact of predicted stress agents but also the oak physiological responses (i.e. resilience) to each stress agent. We suggest keeping low ungulate densities and carefully consider the species selection in assisted regeneration projects depending on the predominant stress agent and microsite.