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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.

Damage caused by cloven-hoofed game and wild animals is a serious problem in Slovakia and neighboring countries. In 2022, the damage to forests in Slovakia was estimated at a level of almost EUR 2.9 million. Despite several implemented measures, the situation is so severe that successfully restoring some trees in some heavily attacked stands is impossible. This paper deals with the preventive elimination of damage caused by red deer in forest stands by the biological method of applying tannin-based mineral licks. Specifically, licks containing tannin obtained from the edible chestnut were used for testing. Several positive effects are attributed to tannins in developing livestock and animal fitness status. To date, however, the question of using tannins as biological agents for the possible protection of forest stands has not been addressed. Therefore, red deer damage was assessed at two localities with similar natural conditions in the central part of the Western Carpathians to explore such a possibility. After the initial sample measurement of the bark-stripping damage caused by the red deer in the autumn, mineral licks with tannin were placed in one selected study area over the winter. The levels of and differences in forest damage by deer between areas with the application of licks with tannin and without tannin were detected in spring of the following year. In the location treated with tannin, the number of damaged sample plots decreased, and the mean plot damage did not increase (no statistically significant differences were registered in mean plot damage between autumn and spring). Meanwhile, in the control location, the total amount of bark-stripped area doubled, mainly due to a statistically significant increase in mean plot damage between autumn and spring. Based on this, we conclude that tannin had a significant preventive effect and considerably reduced the extent of bark stripping. Such promising results indicate that tannin licks can effectively mitigate the problem of bark-stripping damage in areas heavily attacked by red deer. [ABSTRACT FROM AUTHOR]

The foraging behavior of ruminating ungulates significantly impacts forest ecosystems due to their nutritional requirements. This study focuses on inter-specific comparisons of bark browsing (stripping) between Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) and silver fir (Abies alba Mill.). Field measurements were conducted at the previously established research demonstration site "Husárik" in the Javorníky Mountains, north-western Slovakia. We measured the sizes of wounds on stems and assessed the dimensions of unrecovered parts of wounds, subsequently calculating areas of recovered bark patches. Then, the total areas of wounds recovered patches, and unrecovered parts were measured. Additionally, the percentages of wound areas, recovered areas, and unrecovered areas were expressed as proportions relative to the total bark surface. Influencing factors such as the position of wounds along the vertical stem profile and stem diameter class were analyzed using two- and three-way ANOVA followed by Fisher's LSD test. The results demonstrate the susceptibility of both tree species to bark browsing by ruminating ungulates, primarily red deer (Cervus elaphus L.) in our study site. Douglas fir exhibited slightly less intense browsing compared to silver fir, while silver fir had a slightly higher recovery rate. Specifically, 17.0% of the bark surface in Douglas fir and 21.5% in silver fir were browsed. The proportions of recovered areas on wounds were 62.5% and 69.6% in Douglas fir and silver fir, respectively. Regarding the vertical stem profile, the most intense browsing occurred at a height of 101–125 cm from the ground level, with rates of 40.7% in Douglas fir and 47.0% in silver fir. Browsing intensity showed negligible variation among diameter classes, which were classified as up to 35 mm, 35–50 mm, and over 50 mm. Our findings suggest that, as an introduced species, Douglas fir is not a suitable substitute for other commercially significant tree species in supporting sustainable forestry in European countries where ruminating ungulates are overabundant. [ABSTRACT FROM AUTHOR]

Aim of study: Pallas´s squirrel (Callosciurus erythraeus) is a harmful and generalist invasive mammal species that causes different problems in the forestry sector. The aim of this study was to evaluate the damage on the wood in three commercial tree species in Argentina, Eucalyptus dunnii, Populus deltoides and Pinus elliottii, due to debarking caused by this squirrel species. Area of study: ¨Liebres Fue¨ forest plantation, located in Luján District (Province of Buenos Aires, Argentina). Material and methods: We analyzed affected tissues and internal defects of wood associated with debarking signs. We randomly collected 74 stems of the three forest species with (N=62) and without debarking (N=12) between October 2016 and December 2017. Transversal cuttings (N=37) and longitudinal cuttings (N=37) of the stems were analyzed. Main results: The defects inside the wood related to the damage due to the debarking caused by Pallas´s squirrels are described. All the damaged samples presented affected wood tissues, with unfavorable healing forming ribbed cracks and ram`s horn scars and/or presence of some internal defect (crack, crack with abnormal coloration, crack with kino/resin or crack with bark included). None of the damaged pieces, according to the rules of visual classification of sawn woods, showed the highest quality grade (Premium). Research highlight: Pallas´s squirrel action causes wounds on the trees, leading to different responses by the trees that are transferred internally, showing abnormalities in the wood which diminish its value from a commercial point of view.

The occurrence of bark stripping associated with increased deer densities can severely damage forests. Identifying trends in bark stripping is crucial for forest management, but such data are often difficult to obtain through field surveys. Therefore, this study aimed to develop an efficient monitoring method using unmanned aerial vehicles (UAVs) that can detect the occurrence of bark stripping and enable long-term monitoring. The area around the Ochiai Pass in Higashi-Iya Ochiai, Miyoshi City, Tokushima Prefecture, Japan, was selected as the study area for the survey of Abies homolepis, which was found to be significantly bark-stripped by deer in the field. The location and root diameter of A. homolepis were measured, and the percentages of bark stripping and tree growth were visually determined. Simultaneously, normalized difference vegetation index (NDVI) and visible light orthomosaic images were produced using a UAV. A canopy polygon of A. homolepis was created, and the average value of the NDVI within the polygon was calculated. Where the bark stripping rate at the root edge was greater than 75%, the number of "partially dead" and "dead" trees increased significantly, indicating that bark stripping by deer was the primary cause of the death of A. homolepis in Ochiai Pass. In addition, the mean value of the NDVI was significantly lower, with a bark stripping rate of 75% or higher, indicating that the NDVI of the canopy of A. homolepis can be used to estimate individuals with a high bark stripping rate at the root tips, that is, those with a high probability of mortality. Furthermore, by extrapolating the results of the tree-by-tree survey to the nontarget A. homolepis, we detected 46 (8%) A. homolepis with an average NDVI value of 0.8 or less (i.e., those with a bark stripping ratio of 75% or higher and a high probability of mortality). Therefore, the utilization of remote sensing technology via UAVs, as demonstrated in this study, proves to be a potent means for monitoring the incidence of bark stripping. [ABSTRACT FROM AUTHOR]

With a drastic decrease in their populations over the last decades, forest elephants Loxodonta cyclotis are facing increasing human pressure. Their decline will have serious ecological consequences, as they are key actors in shaping ecosystems. Whilst timber concessions host many mammal species, the interactions between selective logging and forest elephants remain unclear.Through an extensive literature review, we discussed the following: 1) the ecological and human factors that drive the distribution of forest elephants on a large scale as well as in the specific context of logged forests; 2) the contribution of forest elephants to the regeneration of timber species; and 3) the damage caused by forest elephants to timber species.Although human activities have the greatest impact on forest elephant distribution, it is the availability of food, water, and minerals that locally determines their use of the habitat. Under specific conditions, timber concessions may host large populations of forest elephants.As effective seed dispersers, forest elephants contribute to the regeneration of at least 41 timber species, such as Bobgunnia fistuloides (pao rosa), one of the most expensive woods on the market.Damage caused by forest elephants is diverse and affects a wide range of species. From branch breaking to bark stripping, at least 61 timber species are used by forest elephants, and little is known about the consequences for the tree's vitality and wood quality.The interactions between forest elephants and logging are complex and involve many variables, requiring additional research. Nevertheless, this review suggests that timber concessions constitute key areas for forest elephant conservation, provided that low‐impact logging and wildlife management are implemented. [ABSTRACT FROM AUTHOR]

The integration of genomic data into genetic evaluations can facilitate the rapid selection of superior genotypes and accelerate the breeding cycle in trees. In this study, 390 trees from 74 control-pollinated families were genotyped using a 36K Axiom SNP array. A total of 15,624 high-quality SNPs were used to develop genomic prediction models for mammalian bark stripping, tree height, and selected primary and secondary chemical compounds in the bark. Genetic parameters from different genomic prediction methods--single-trait best linear unbiased prediction based on a marker-based relationship matrix (genomic best linear unbiased prediction), multitrait single-step genomic best linear unbiased prediction, which integrated the marker-based and pedigree-based relationship matrices (single-step genomic best linear unbiased prediction) and the single-trait generalized ridge regression--were compared to equivalent single- or multitrait pedigree-based approaches (ABLUP). The influence of the statistical distribution of data on the genetic parameters was assessed. Results indicated that the heritability estimates were increased nearly 2-fold with genomic models compared to the equivalent pedigree-based models. Predictive accuracy of the single-step genomic best linear unbiased prediction was higher than the ABLUP for most traits. Allowing for heterogeneity in marker effects through the use of generalized ridge regression did not markedly improve predictive ability over genomic best linear unbiased prediction, arguing that most of the chemical traits are modulated by many genes with small effects. Overall, the traits with low pedigree-based heritability benefited more from genomic models compared to the traits with high pedigreebased heritability. There was no evidence that data skewness or the presence of outliers affected the genomic or pedigree-based genetic estimates. [ABSTRACT FROM AUTHOR]

Bark stripping by red deer (Cervus elaphus L.) is one of the most acute instances of damage wrought by these animals in a forest. Because of its location, bark stripping causes damage to the thickest and most valuable part of the tree trunk, which lowers the quality of the wood due to technical flaws. The research was conducted in 25 sampling sites of pine stands aged 35 years in a mixed, fresh forest habitat in south-western Poland. The study was aimed at assessing the influence of bark damage by deer on biometric parameters of pine stands (Pinus sylvestris L.). The assessment involved the diameter at breast height, height, basal area and volume of the tree stands. The results revealed a strong deer-specific pressure on the analysed pine stands. The share of bark stripped trees ranged from 65% to 96%. The number of bark damage instances (NBDI) on a given tree was found to significantly affect its diameter at breast height. The strip-damaged trees had breast height diameters lower by 23% on average, and their mean height was lower by 8.7% as compared with the trees without damage. The mean reduction in basal area increments ( G 1.3 ) of the trees was identified at 39%. In a similar way to the diameter at breast height and the basal area, the losses in tree stand volume growth caused by deer stripping were significant and oscillated at 41%. [ABSTRACT FROM AUTHOR]

The aim of the study was to analyse the changes in the infection rate development inside the beech stem as a result of browsing by deer (Cervus elaphus). The research materials were collected from three research plots located in the Polanów Forest Inspectorate from March to April 2020. For the study, 80 beech trees were selected, for which the size of the fallow tree, the percentage of the section taken from its centre infected with rot, and the number of years passed since the tree was wounded were determined. The study shows that the infection affects only the rings formed before the tree was injured. The average size of stem rot was 7.75% of its area, and it spread at the rate of 2.52% of the cross-sectional area per year. The analysis of the obtained results proved that both the size of the wound (splits) and the time elapsed since the tree was damaged are significantly correlated with each other. It is also possible to build a model for estimating the size of decay in stunted beech trees based on easy-to-determine predictors, such as maximum wound width and elapsed time since tree damage. [ABSTRACT FROM AUTHOR]

Bark stripping by red deer has a significant impact on the state of forest ecosystems throughout the range of this ungulate species. Range-wide, red deer eat the bark of more than 20 species of trees, often causing significant damage to forestry. In the south of the Russian Far East, Manchurian red deer Cervus elaphus xanthopygus feed on the bark of elms Ulmus sp. in autumn and spring. However, prior research on the ecology of Manchurian red deer contains no quantitative estimates of the removal of elm bark by this ungulate. This article presents, for the first time, quantitative data on the influence of such deer feeding behavior on the forest stand of Primorsky Region. Manchurian red deer mainly damage undergrowth and young trees up to 40 years old with diameters of 0.5–7.4 cm at breast height (M = 3.75 ± 0.069, n = 249). In Ulmus laciniata undergrowth, the damaged bark area was 0.01–0.45 m2 (M = 0.11 ± 0.096, n = 249). At the same time, the deer scraped more bark from large trees by area on average when converted to one tree.

Goats are being used increasingly to manage woody invasive plants in woodland habitats, but their specific impacts on those plants over a period of time during active, periodic browsing has not been documented. This study investigated bark-stripping by goats browsing on common buckthorn in savanna habitats (75 goats/hectare, 5 to 7 days), focusing on possible size-selective feeding and the cumulative effects of repeated, periodic browsing over a 3-year period. When surveyed after the first browsing period, bark was stripped selectively on buckthorn stems 20 to 60 mm in diameter. Approximately 60% of all stripped stems were completely girdled, but only 14–17% of stems were bark-stripped. After five browsing periods, 66% of standing stems displayed bark stripping and 39% were completely girdled. Buckthorn densities were reduced by 90% compared to the first browsing period, the decline resulting mostly from consumption of foliage and terminal shoots of small (< 20 mm) buckthorn and bark-stripping resulting in top-kill in intermediate-sized (20–60 mm) plants. Large buckthorn (> 60 mm) were largely unimpacted by goats. Relatively few (28%) seedling buckthorn were browsed by goats, although > 90% of 2nd-year plants were browsed. Buckthorn can be managed in part via goat browsing, but repeated, periodic browsing over 3 to 6 years may be necessary to produce a significant reduction in plant abundance, and other techniques will be needed to eliminate large, seed-producing plants. [ABSTRACT FROM AUTHOR]

Key message: In Pinus radiata, both primary and secondary compounds may play a role in defence against herbivory. Allocation of constitutive and induced primary and secondary compounds varies among needles, bark and roots. Responses to stresses are stronger in primary than secondary compounds and some responses of root chemistry to above-ground stressors were detected. The capacity of trees to cope with pests and pathogens depends in part on the variation of constitutive and induced chemical defences within the plant. Here we examined the constitutive and induced variation of primary (sugars and fatty acids) and secondary (mono-, sesqui- and di- terpenoids as well as volatile phenolics) metabolites in the needles, bark and, for the first time, roots of 2-year old Pinus radiata. A total of 81 compounds were examined. The plant parts differed significantly in constitutive levels of individual sugars, fatty acids, mono-, sesqui- and di- terpenoids as well as volatile phenolics. Overall, the bark had more compounds and a higher amount of most secondary compounds and the levels of compounds in the roots differed from that of the needles and bark. For example, glucose was the dominant sugar in the needles and bark whereas fructose dominated in the roots. Of the fully identified secondary compounds, monoterpenoids dominated in all plant parts but with different qualitative patterns. Following methyl jasmonate and bark stripping treatments, a marked reduction in sugars but weaker changes in secondary compounds were detected in the needles and bark. Responses in the roots were minor but the few that were detected were mostly in response to the bark stripping treatment. Changes in correlations among chemicals within plant parts and between the same compound across the different plant parts were also detected after stress treatments. Overall, results showed that the constitutive composition in the roots differs from that of the bark and needles in P. radiata and inducibility is stronger in the primary than secondary metabolites and differs between plant parts. This detailed assessment of Pinus radiata chemistry in the needles, bark and roots, including the compounds that respond to simulated biotic stress will potentially facilitate the identification of related chemical defence traits. [ABSTRACT FROM AUTHOR]

ABSTRACT Deer can show transitional use between agricultural fields and forests for foraging and shelter. Such transitional use may affect forest damage as nutrient balancing theory suggests that if deer ingest large amounts of nutrient‐rich food, complementary browse, such as bark, may be required to balance the diet. We investigated the relationship between the level of red deer Cervus elaphus bark‐stripping damage in 68 Norway spruce Picea abies stands and the presence of rapeseed Brassica napus fields – an energy‐rich crop preferred by red deer – in the surroundings, hypothesizing that damage increases with decreasing distance to rapeseed fields. We also considered other potentially influencing factors, such as supplemental feeding, alternative forage availability, and deer use of spruce stands as indexed by a pellet group count. Spruce stands closer to rapeseed had a significantly higher proportion of damaged stems. The increased level of bark‐stripping damage was not explained by a higher stand use of deer closer to rapeseed fields, indicating that deer increase their consumption of bark in order to balance their diet. Similarly, spruce stands closer to supplemental feeding stations had significantly higher damage levels. In line with earlier findings, damage levels were negatively related to the amount of available browse in the forest. This emphasizes the importance of alternative forage for reducing the damage risk in forest plantations. Our study shows that the availability of fields with nutrient‐rich food, such as rapeseed, as well as supplemental feeding needs to be considered when predicting the level of forest damage. With a high availability of nutrient‐rich food in the vicinity of forest stands, a higher damage level can be expected and counteractions could be taken such as increased disturbance, harvest or changed choice of both crop and supplemental feed types. These actions may also be combined with a push–pull strategy where the deer are steered to disturbance‐free zones insensitive to damage and with alternative forage. The importance of alternative forage availability on damage levels highlights the necessity for managers to actively promote tree and shrub forage within and around their production stands.

Questions: Ungulate herbivory and its impact on one plant species may be driven by other plants in the neighbourhood. Although such neighbourhood effects have long been recognized, there is limited understanding of how spatial variation in these effects relates to local plant density and distances between plants. Our goal was to examine if the density of or distance to conspecific and heterospecific neighbouring woody individuals produces neighbourhood effects on bark stripping by deer, and how these effects differ in spatial scale and type (reduce/increase herbivory). Location: Lowland old-growth forest, Czech Republic. Methods: Woody individuals were assessed for evidence of bark stripping and the level of damage done by deer in a square 4-ha plot, mapping all woody stems ≥1 cm diameter at breast height. The spatial distribution of stripping was used to examine neighbourhood effects using spatial point pattern methods. Results: The density and distance to neighbours and species identity of focal and neighbouring individuals contributed to a large spatial variation in neighbourhood effects (up to distances of 2-30 m from neighbours). Neighbourhood effects arose mainly from the interactions between neighbouring shrub species and all tree species, and interactions between individual species pairs. Neighbourhood effects more often increased than reduced the stripping of focal individuals. The stripping of Ulmus laevis, Acer campestre and Crataegus laevigata increased near conspecifics, while the stripping of all tree species was more likely near Ulmus laevis, Fraxinus angustifolia and shrubs. Heterospecific tree species were less susceptible to stripping near Tilia cordata and especially Carpinus betulus. Conclusion: Our study provides new insight into neighbourhood effects by showing how and at which spatial scales woody plant interactions modify deer herbivory. We advocate considering the life stage and relevant plant traits with multivariate spatial methods in order to elucidate the role of neighbourhood effects in complex plant communities. [ABSTRACT FROM AUTHOR]

Bark stripping by mammals is a major problem in managed conifer forests worldwide. In Australia, bark stripping in the exotic plantations of Pinus radiata is mainly caused by native marsupials and results in reduced survival, growth, and in extreme cases death of trees. Herbivory is influenced by a balance between primary metabolites that are sources of nutrition and secondary metabolites that act as defences. Identifying the compounds that influence herbivory may be a useful tool in the management of forest systems. This study aimed to detect and identify both constitutive and induced compounds that are associated with genetic differences in susceptibility of two-year-old P. radiata trees to bark stripping by marsupials. An untargeted profiling of 83 primary and secondary compounds of the needles and bark samples from 21 susceptible and 21 resistant families was undertaken. These were among the most and least damaged families, respectively, screened in a trial of 74 families that were exposed to natural field bark stripping by marsupials. Experimental plants were in the same field trial but protected from bark stripping and a subset were subjected to artificial bark stripping to examine induced and constitutive chemistry differences between resistant and susceptible families. Machine learning (random forest), partial least squares plus discriminant analysis (PLS-DA), and principal components analysis with discriminant analysis (PCA-DA), as well as univariate methods were used to identify the most important totals by compound group and individual compounds differentiating the resistant and susceptible families. In the bark, the constitutive amount of two sesquiterpenoids — bicyclogermacrene and an unknown sesquiterpenoid alcohol —were shown to be of higher levels in the resistant families, whereas the constitutive sugars, fructose, and glucose, as well individual phenolics, were higher in the more susceptible families. The chemistry of the needles was not useful in differentiating the resistant and susceptible families to marsupial bark stripping. After artificial bark stripping, the terpenes, sugars, and phenolics responded in both the resistant and susceptible families by increasing or reducing amounts, which leveled the differences in the amounts of the compounds between the different resistant and susceptible classes observed at the constitutive level. Overall, based on the families with extreme values for less and more susceptibility, differences in the amounts of secondary compounds were subtle and susceptibility due to sugars may outweigh defence as the cause of the genetic variation in bark stripping observed in this non-native tree herbivory system. [ABSTRACT FROM AUTHOR]

The occurrence of bark stripping associated with increased deer densities can severely damage forests. Identifying trends in bark stripping is crucial for forest management, but such data are often difficult to obtain through field surveys. Therefore, this study aimed to develop an efficient monitoring method using unmanned aerial vehicles (UAVs) that can detect the occurrence of bark stripping and enable long-term monitoring. The area around the Ochiai Pass in Higashi-Iya Ochiai, Miyoshi City, Tokushima Prefecture, Japan, was selected as the study area for the survey of Abies homolepis, which was found to be significantly bark-stripped by deer in the field. The location and root diameter of A. homolepis were measured, and the percentages of bark stripping and tree growth were visually determined. Simultaneously, normalized difference vegetation index (NDVI) and visible light orthomosaic images were produced using a UAV. A canopy polygon of A. homolepis was created, and the average value of the NDVI within the polygon was calculated. Where the bark stripping rate at the root edge was greater than 75%, the number of “partially dead” and “dead” trees increased significantly, indicating that bark stripping by deer was the primary cause of the death of A. homolepis in Ochiai Pass. In addition, the mean value of the NDVI was significantly lower, with a bark stripping rate of 75% or higher, indicating that the NDVI of the canopy of A. homolepis can be used to estimate individuals with a high bark stripping rate at the root tips, that is, those with a high probability of mortality. Furthermore, by extrapolating the results of the tree-by-tree survey to the nontarget A. homolepis, we detected 46 (8%) A. homolepis with an average NDVI value of 0.8 or less (i.e., those with a bark stripping ratio of 75% or higher and a high probability of mortality). Therefore, the utilization of remote sensing technology via UAVs, as demonstrated in this study, proves to be a potent means for monitoring the incidence of bark stripping.

Bark stripping by red deer (Cervus elaphus L.) is one of the most acute instances of damage wrought by these animals in a forest. Because of its location, bark stripping causes damage to the thickest and most valuable part of the tree trunk, which lowers the quality of the wood due to technical flaws. The research was conducted in 25 sampling sites of pine stands aged 35 years in a mixed, fresh forest habitat in south-western Poland. The study was aimed at assessing the influence of bark damage by deer on biometric parameters of pine stands (Pinus sylvestris L.). The assessment involved the diameter at breast height, height, basal area and volume of the tree stands. The results revealed a strong deer-specific pressure on the analysed pine stands. The share of bark stripped trees ranged from 65% to 96%. The number of bark damage instances (NBDI) on a given tree was found to significantly affect its diameter at breast height. The strip-damaged trees had breast height diameters lower by 23% on average, and their mean height was lower by 8.7% as compared with the trees without damage. The mean reduction in basal area increments (G1.3) of the trees was identified at 39%. In a similar way to the diameter at breast height and the basal area, the losses in tree stand volume growth caused by deer stripping were significant and oscillated at 41%.

The management of deer impacts on forested lands requires quantification of the negative factors (e.g., bark stripping) on tree survival in relation to other ecological variables (e.g., competition from neighboring trees). This study measured the effects of bark stripping by sika deer, Cervus nippon, and competition among trees on the survival of Abies veitchii in a subalpine coniferous forest in central Japan over 12 years. Most of the trees subjected to bark stripping by deer were small (< 10 cm in diameter at breast height); however, some trees were stripped repeatedly. Although light bark stripping did not strongly influence tree survival after 12 years, heavily stripped stems (i.e., > 65% of the stem circumference stripped) were severely affected. The effect on longevity for each tree after bark stripping was explained by maximum bark stripping intensity during the study period, rather than initial bark stripping intensity. When > 85% of the stem circumference had been stripped, survival rates decreased. Bark stripping influenced survival rates much more than competition from neighboring trees. Because bark stripping occurred repeatedly, frequent measurements are important to grasp the full effects caused by this action. Heavy bark stripping of a stem enhances tree mortality. Thus, management of bark stripping is an essential element of stand maintenance and species composition in subalpine coniferous forests in Japan. [ABSTRACT FROM AUTHOR]

Introduced squirrels threaten forest ecosystems by debarking, resulting in economic losses to the timber industry and additional damage mitigation and pest control costs. The Pallas's squirrel, also called the red-bellied squirrel. (Callosciurus erythraeus), originally from Asia, is the first squirrel species introduced to South America. In Argentina, C. erythraeus causes bark stripping damage in several tree species but their impact on tree growth and wood quality has not been evaluated yet. Field work was undertaken during 2016 in a forest establishment in Lujan district, Buenos Aires Province, Argentina. Samples were taken in plantations of Pinus elliottii, Eucalyptus dunnii and Populus deltoides. For each tree species, we sampled two plantations (1–3 ha) that belonged to two age classes comprised of young and mature trees. Two or three transects, 50 m apart, were set up within each plantation and data collected from individual trees. We evaluated affected tissues, percentage of girdling (percentage of circumference of stem with damage), wood volume and stem defects on damaged and undamaged trees. Wounds damaged live tissues and reached the xylem, causing deformations in the growth rings of all the evaluated trees. Partial girdling was prevalent in younger P. elliottii and P. deltoides (more than 40% on average) and in both ages of E. dunnii (more than 50% on average). Minimum damage caused by squirrels was statistically significant among age classes for both P. elliottii and P. deltoides at 3 m and 6 m tree height. This is the section of the tree most relevant to the wood market. The damage resulted in wood-volume losses between 20% and 58% with diameter at breast height and/or height reduction in some plantations. In E. dunnii and P. deltoides the stem breaks were significant. The results of this study suggest that the Pallas's squirrel may have an adverse impact on commercial forestry as a result of their continuous damage to trees, which leads to yield reduction and consequent economic losses. [ABSTRACT FROM AUTHOR]

Highlights • Bears strip bark in conifer plantations and cause serious damage. • Standing trees wrapped with biodegradable material netting receive little damage. • We studied the effects of net installation on damage to neighboring trees. • Installing these materials can also curb damage in surrounding stands. Abstract Bark stripping by Asian black bears (Ursus thibetanus) has a serious impact on conifer plantations in Japan. Prevention strategies tend to be implemented on a tree-by-tree basis by wrapping standing trees in biodegradable tape or netting. It remains unclear, however, whether installing these materials has a beneficial effect on untreated trees in surrounding stands. The aim of this study was to clarify the effects of installing these materials on bark stripping by bears in neighboring areas. The study was conducted in eastern Gunma Prefecture, central Japan. We selected 113 stands of Cryptomeria japonica and Chamaecyparis obtusa treated with these materials and 162 untreated stands (7963 trees). In untreated stands, we established square plots and calculated the rates of damage by bears. Generalized linear mixed models were used to analyze the effects of various factors on bark stripping, and segmented regression analysis was used to determine whether the rate of bark stripping in untreated stands had increased after material installation in treated stands. The rates of damage to Japanese cedar and Japanese cypress by bears in treated stands 1 or 2 years after material installation were 0% and 0%, respectively. In contrast, rates of damage to Japanese cedar and Japanese cypress in untreated stands surrounding the treated stands were 2.6% ± 1.8% and 2.7% ± 1.2%, respectively, at 1 year and 2.7 ± 1.5% and 2.8 ± 1.2%, respectively, at 2 years after material installation. We found that bark stripping by bears tended to occur in untreated stands far from treated stands at 1 or 2 years after installation. The segmented regression models showed that the rate of occurrence of bark-stripping damage at 1 and 2 years after treatment was markedly lower in untreated stands close to treated stands than in those beyond the breakpoints, and it increased only weakly in farther stands. Our findings indicate that installing tape or netting in selected stands can curb the occurrence of bark-stripping damage in surrounding stands within a certain distance. That is, material installation in individual stands did not lead to displaced bark-stripping activity in surrounding areas. [ABSTRACT FROM AUTHOR]

Due to biotope fragmentation and changes in landscape structure, opportunities for forest animals to migrate and obtain food are diminishing, especially during extreme winter conditions. The main objective of this research was an assessment of ungulates, impact on woody species, evaluation of damage forms and bark renewal phases of affected woody plants. The study area is located in western Slovakia in the southeast part of Male Karpaty Mts. After the very cold and long winter of 2012/2013, 34% of woody plants were damaged by bark stripping and biting on the forest locality and 53% of evaluated trees and shrubs were damaged by biting off shoots in the non-forest locality. Together, 262 woody plants belonging to 15 species were evaluated; the girth of tree trunks and stripped bark patches were measured. The most severely affected tree species, suffering from bark stripping and bitten-off sprouts, was Fraxinus excelsior; Acer campestre was also significantly affected. Results showed that woody plants provide a significant part of hoofed mammal nutrition (especially Capreolus capreolus and Cervus elaphus). The stripped bark dendromass per forested area of 625 m2 reached 3 m2. After the mild winter in 2014, the majority (93.7%) of previously affected Fraxinus excelsior trees in the forest locality had only old damages with renewed bark in different phases of regeneration. In the non-forest locality, 96% of young Fraxinus excelsior, damaged in the winter of 2013, shot up new sprouts. The mortality of affected trees was minimal (4−5%).

Highlights • Extent and intensity of deer browsing was higher on felled than standing rowans. • Browsed mass on trees, especially on felled ones, increased with their height. • Cut timing and after-cut arrangement may substantially mitigate browsing. Abstract Because red deer (Cervus elaphus) forage extensively on woody plants, browsing is a serious problem in forest stands especially in initial growth stages. In Slovakia, rowans (Sorbus aucuparia) are the most attractive tree species for red deer, and when present, they may serve to divert the attention of foraging red deer from commercial forest stands. In this study we compared the extent of herbivory by red deer on standing and freshly-felled rowans within a mixed conifer forest. We quantified the biomass of stem bark, branch bark and whole branches consumed by red deer on 60 rowans between 200 and 600 cm tall within young stands that regenerated after a large scale windstorm in the Tatra National Park, Northern Slovakia. We calculated the dry biomass of browsed branches using allometric relationships with branch diameter and browsed bark biomass from the product of the area of consumed bark and specific surface mass of bark. We found that the extent and intensity of browsing was much higher on felled than standing rowans. The number of patches of stripped bark on stems was twice as high (12 ± 6 bites/stem) on felled than on standing trees (6 ± 2 bites/stem). Similarly, red deer consumed more total biomass (i.e., bark stripping on both stem and branches and browsed whole branches) from felled (45 ± 41 g) than standing (28 ± 22 g) rowans. Red deer consumed more mass from stem bark than branches. Total browsed mass on trees (especially on felled ones) increased with their height. Based on our findings, we recommend cutting rowans after most trees exceed 500 cm in height and leaving them in the site. However, if rowans have been intensively damaged by browsing and the forage potential of the stem bark and branches is reduced, trees can be felled before they reach 500 cm. We concluded that cut timing and after-cut arrangement of rowans, and likely other non-commercial tree species attractive to red deer, may substantially mitigate red deer browsing on commercial tree species in young stands. [ABSTRACT FROM AUTHOR]

Key message: Two artificially debarked Afrotemperate tree species showed different trade-offs between wound closure and compartmentalisation of decay in the stem. One species had a relaxed trade-off but inefficient defence, and the other showed more efficient defence but a substantial trade-off. Abstract: Bark stripping for medicinal use is a common cause of damage in several indigenous tree species in natural forests of South Africa. Ocotea bullata and Curtisia dentata are in high demand for their bark for medicinal purposes. The study aimed at revealing intra-specific and inter-specific differences of tree growth rates wound closure and decay containment responses ten years after experimental bark harvesting. The results obtained on computer tomography scans of twenty trees showed that C. dentata had significantly higher decay percentages compared to O. bullata, indicating that O. bullata was able to more efficiently contain decay than C. dentata. While decay in O. bullata was confined at the wounded tissues, decay in the C. dentata extended below and above the wounded area. Intra-specifically, O. bullata showed strong positive correlations between tree growth rates and wound closure rates, and wound closure rates with relative volume of decayed wood, indicating that individuals with higher rates of growth and wound closure suffered higher percentages of decay. Results confirmed an intra-specific trade-off between growth rate and defense investment, with fast growing trees showing high percentage decay (poor compartmentalization of decay). Inter-specifically, however, growth versus defense trade-off did not present itself. For C. dentata, no correlations were found between rates of wound closure and percentage decay. The findings and conclusions derived from this study reveal complex, species-specific responses to damage. This study highlights the need to gain an in-depth understanding of underlying morphological, phylogenic, physiological characteristics of species to further explain the observed species differences. [ABSTRACT FROM AUTHOR]

The North Island kākā (Nestor meridionalis septentrionalis), a threatened New Zealand native parrot, was successfully reintroduced to an urban sanctuary in Wellington, New Zealand. Conflict has recently begun to emerge with Wellington City residents due to tree damage caused by kākā sap foraging. Little is known about sap foraging behavior of kākā, and this study aimed to gain a greater understanding of this behavior, and to test hypotheses that sap feeding is predominantly a female activity and that one technique, forming transverse gouges through bark, may be restricted to adult kākā. We used instantaneous scan sampling to record the behavior of kākā during 25 60–100 minute observation periods at Anderson Park, Wellington Botanic Garden, and during 13 opportunistic observations of sap feeding kākā in Wellington City. Forty-one observations of sap feeding were made of 21 individually-identified birds. Sap feeding birds were predominantly young and, based on estimated sex, females were no more likely to sap feed than males (exact binomial test p = 0.868). Twenty of the 21 identified sap feeding kākā utilized supplementary feeding stations at Zealandia-Karori Wildlife Sanctuary. Kākā were observed defending sap feeding sites from tui (Prosthemadera novaeseelandiae) and conspecifics. Sap appears to be an important resource for kākā across sexes and life stages, and provision of supplementary food is unlikely to reduce sap feeding and tree damage in Wellington City.

African elephants (Loxodonta africana) are ecosystem engineers in that they substantially alter the environment through their unique foraging and feeding habits. At high densities, elephants potentially have negative impacts on the environment, specifically for large trees. Because of this, recent increases of elephants in the Associated Private Nature Reserves (APNR) on the western boundary of the Kruger National Park (KNP), South Africa, have caused concern regarding the survival of several tree species. Our objective was to assess the effectiveness of wrapping protective wire netting around the trunk of the tree for preventing and reducing bark stripping, branch breaking, and felling by elephants. We assessed 2668 trees – 1352 Sclerocarya birrea (marula), 857 Acacia nigrescens (knobthorn), and 459 Lannea schweinfurthii (false marula) – for elephant impact in the APNR, 1387 (52%) of which had previously been wrapped in protective wire netting (789, 548 and 50, respectively). Wire netting was effective in reducing the severity of bark stripping and the relative proportion of trees that were bark stripped. In addition, wire netting had an effect on the level of impact, with a higher relative frequency of wire-net-protected trees found in lower impact categories compared with unprotected trees. Since tree mortality has been attributed to high levels of elephant impact, the use of wire netting could serve to maintain individual trees or populations particularly vulnerable to elephant impact in areas with locally high densities of elephants. Conservation implications: Since wire netting is a relatively low cost and ecologically unobtrusive strategy, it could be used to reduce elephant impact in problem areas. This method focuses on protecting trees rather than some other strategies such as environmental manipulation, translocation, contraceptives, and culling that instead focus on reducing elephant numbers. Keywords: Elephant impact; bark stripping; large trees; wire netting; mitigation measures

Bark stripping damage is a serious problem in some forest hunting grounds in Serbia. This study aimed at assessing the incidence and intensity of bark stripping by red deer in the fenced rearing centre “Lomnička Reka“ (Mt. Veliki Jastrebac, central Serbia). The data were collected by detailed surveying of the entire rearing centre over spring and autumn 2008, 2009 and 2010. Our results show that, in spring and summer, it is exclusively broadleaf tree species that are bark stripped by red deer, mainly beech (86.3% or 536 trees) and hornbeam (10.1% or 63 trees). The incidence and intensity of bark stripping were the highest in the diameter class of 20-39.9 cm. Damaged trees were identified in all parts of the rearing centre, at all aspects and at different slopes. Beech bark was stripped over the period May-August, with the focus in June or July.

The systematic study and assessment of the damage by big game in forest hunting grounds in Serbia was infrequent, although the damage was evident. The objective of this paper is to identify the rates and types of damage by red deer and wild boar at three localities: (1) fenced part of the hunting ground 'Crni Lug' (Srem), (2) fenced part of the hunting ground 'Podunavsko Lovište Plavna' (Southwestern Bačka), and (3) fenced rearing centre 'Lomnička Reka' (Mt. Veliki Jastrebac). The damage was not recorded on locality (1). The damage on locality (2) (new polar plantations) and locality (3) (beech forests) was caused by red deer. The main causes of the damage were excessive density and disturbed population structure (sex and age), nonharmonised forest and hunting management, shortage of natural food, especially of pasture areas.

Debarking by ungulates has various effects on stem development and forest tree composition. Selectivity for debarking may prevail based on tree species and stem girth. We investigated this selective utilization based on species and size composition of available and debarked stems. Measurements were taken on 2100 sampling points in different temperate deciduous forests of Mátra Mountains region, Hungary. We distinguished specific stem injuries from each other. Factors influencing debarking (stem density and diversity, understory browsing) were also studied. Frequency of debarking was very low (5 % of sampling points). It was the lowest in beech forests (0.2 %) and the highest in Turkey oak-sessile oak forests (6 %). The proportion of injured stems varied between 0.001 % in beech forests to 0.04 % in Turkey oak-sessile oak forests. Ash, linden and maple trees were the most utilized; ash was revealed as significantly preferred species. Most of the injured stems had a perimeter between 12 and 21 cm, proved as preferred stem size interval. Trunks larger than 50 cm girth were generally avoided. Bark stripping and antler rubbing occurred mainly on thinner ash stems, whereas bark rubbing on larger oak stems. Understory density and diversity was significantly higher at debarked sampling points than intact ones. Ungulate debarking is functioning as selective natural disturbance. As a driver of forest vegetation dynamics, its total elimination should not be targeted from forest ecosystems. We recommend maintaining a diverse forest composition to ensure selective stem utilization of ungulates and reduce damage on major tree species of economic importance. [ABSTRACT FROM AUTHOR]

Bark stripping by Asiatic black bears ( Ursus thibetanus ) has a serious impact on conifer plantations in Japan, resulting in physical damage to the tree trunks and reduction of the value of the timber. The aim of this study was to clarify whether these plantations are more prone to damage by bears at particular times and sites, to more effectively prevent this damaging behavior. The study was conducted at Kusaki University Forest of Tokyo University of Agriculture and Technology in Gunma Prefecture, central Japan. To determine where, when, and how frequently bears strip the bark, we established circular plots in each of 65 stands and felled all trees that had been damaged by bears. In total, we felled 1639 damaged trees, analyzed 1490 samples ( Cryptomeria japonica : 1236, Chamaecyparis obtusa : 254) across the 65 study stands, and calculated the timing of bark stripping for each by counting the number of annual growth rings in each tree. Generalized linear mixed models were then used to examine the effects of various spatiotemporal factors on bark stripping. In terms of temporal variation, we found no relationships between the occurrence of bark stripping by bears and the meteorological conditions from the previous November to the previous March. In terms of spatial variation, there was no relationship between the occurrence of bark stripping by bears and the environmental characteristics of the stands. We did, however, find that stands that experienced bear damage in the previous year were more prone to experiencing bear damage in the current year, and furthermore, the rate at which damage of trees spread during the 10 years after the first occurrence of a damaged tree was significantly faster in young stands. These findings will allow forest managers to predict the conditions that make conifer stands more prone to bear damage, allowing them to make effective forest management plans. Additionally, to reduce bear damage, foresters should focus on direct protection efforts that they would like to protect from bears. [ABSTRACT FROM AUTHOR]

In 2002-2003, we conducted a detailed inventory of bark stripping damage in Forest District (FD) Mořkov (Forest Enterprise Frýdek-Místek) and in Forest Range (FR) Proklest (Training Forest Enterprise Křtiny). In total, 3,988 trees were examined in FD Mořkov and 1,512 trees in FR Proklest; in detail, 52 and 38 sample trees in FD Mořkov and FR Proklest, respectively. The rot spread in stems in the Proklest RD by an average rate of 15.6 cm/year, in FD Mořkov by an average rate of 23.8 cm/year. The rate of the rot spread decreases with the increasing period of parasitizing. The stem length affected by the rot ranged most frequently between 2.5 and 4.5 m (Proklest) or 2 and 3 m (Mořkov). The rot damaged on average 38.8 and 42.4% of the sample tree volume in RD Proklest and FD Mořkov, respectively. The proportion of trees affected by the rot decreased with the stand age. The observed extent of wound rot significantly decreases mechanical stability of stands and their adaptation potential.

The paper deals with the determination of the rate of damage by deer barking and browsing, the subsequent rot caused by Stereum sanguinolentum and the rate of its progress, elucidates causes of damage and quantifies volume and financial losses in the region of Forest Range Mořkov, Forest District Frenštát pod Radhoštěm. In the most damaged 2nd age class, decay by Stereum sanguinolentum was recorded in 59% of damaged trees. The progress of rot ranged from 1 to 70 cm/year. The high number of red deer is considered to be the main reason of extensive damage by bark stripping in the Forest Range Mořkov. The actual financial loss caused by depreciation of wood by the rot is greatest in the 5th age class amounting to CZK 64,320 per ha.

Negative influences on the establishment and persistence of large trees used by tree-nesting birds as nesting sites represent a potential threat to vultures and raptors. We monitored large trees and their surrounding vegetation and analysed whether trees with nesting sites are at risk due to elephant impact. Trees with nests did not differ in elephant impact from control trees without nests, and the survival rates of trees with nests and the actual nests within the trees showed that nests decreased at a faster rate than the trees themselves. Elephant damage did not affect the persistence of nests over the 5-year monitoring period. However, the presence of insects and fungus on large trees was negatively related to tree survival, thereby indicating that elephant impact could indirectly facilitate insect and fungus attack and shorten the lifespan of a tree. [ABSTRACT FROM AUTHOR]

Bark and exudates are widely commercialized non-timber forest products. However, the ecological impacts of the harvesting of these products have seldom been studied. The aim of this study is to investigate the relationship of tree resilience to harvesting intensity in Himatanthus drasticus, a tree that is highly exploited in the Brazilian savanna (Cerrado) for its medicinal latex. Although the traded product is the latex, the traditional harvesting systems involve the removal of the bark of the trees to allow exploitation. A 3-year experiment was conducted in two different Cerrado ecosystems (open savanna and savanna woodland). Trees were debarked at four debarking intensities to simulate the effects of traditional management systems. Measurements of bark growth were taken every 6 months, and quantitative and qualitative indexes of bark regeneration were obtained. The mortality of the debarked trees was low and could not be related to the intensity of harvesting. No signs of attack by fungi or insects were recorded. Compared with other species exploited for bark, H. drasticus is very resilient to harvesting; however, bark regeneration is relatively slow. In both analyzed ecosystems, the regeneration indexes showed higher values in the controls than in the treatments, indicating that 3 years is not sufficient for total recovery of the rhytidome. Bark regeneration occurred primarily by sheet growth and was more rapid in open savanna than in savanna woodland. No differences in the rate of bark recovery were found among management treatments. Based on the results, sustainable harvesting guidelines are suggested for the species. [ABSTRACT FROM AUTHOR]

The North Island kākā (Nestor meridionalis septentrionalis), a threatened New Zealand native parrot, was successfully reintroduced to an urban sanctuary in Wellington, New Zealand. Conflict has recently begun to emerge with Wellington City residents due to tree damage caused by kākā sap foraging. Little is known about sap foraging behavior of kākā, and this study aimed to gain a greater understanding of this behavior, and to test hypotheses that sap feeding is predominantly a female activity and that one technique, forming transverse gouges through bark, may be restricted to adult kākā. We used instantaneous scan sampling to record the behavior of kākā during 25 60--100 minute observation periods at Anderson Park, Wellington Botanic Garden, and during 13 opportunistic observations of sap feeding kākā in Wellington City. Forty-one observations of sap feeding were made of 21 individually-identified birds. Sap feeding birds were predominantly young and, based on estimated sex, females were no more likely to sap feed than males (exact binomial test p = 0.868). Twenty of the 21 identified sap feeding kākā utilized supplementary feeding stations at Zealandia-Karori Wildlife Sanctuary. Kākā were observed defending sap feeding sites from tui (Prosthemadera novaeseelandiae) and conspecifics. Sap appears to be an important resource for kākā across sexes and life stages, and provision of supplementary food is unlikely to reduce sap feeding and tree damage in Wellington City. [ABSTRACT FROM AUTHOR]

Incidence and intensity of bark stripping of trees by ungulates was investigated at no bamboo ( Fargesia nitida (Mitford) Keng f. ex Yi) (B-) site and understory bamboo dominant (B+) site of a subalpine Abies faxoniana Rehder & E. H. Wilson forest, southwest China. The percentage of damaged trees in B-site was higher than in B+ site. Bark stripping obviously occurred more frequently on Abies faxoniana compared to other tree species. Appearance of stripped bark and dead stems of the trees in different size-classes of A. faxoniana strongly depended on the density of dwarf bamboo at the site, and also on the size and bark structure of the trees, with highest damage rates occurring on the smaller DBH classes (10-40 cm) in B-site. The bark stripping intensity of A. faxoniana decreased significantly with higher density and coverage of F. nitida around damaged trees. Therefore, there is an indirect negative effect of the distribution of dwarf bamboo, F. nitida, on bark stripping of tree species. We suggest the indirect effects of dwarf bamboo species should be taken into account while considering the succession and regeneration of natural forests. [ABSTRACT FROM AUTHOR]

• Context: Over the past few decades, the impact of large herbivorous ungulates on forest vegetation has been clearly highlighted. Among those impacts, bark stripping of coniferous trees is one of the most damaging. Bark stripping leads to rot development, inducing serious loss of timber value. • Aims: The present study aimed firstly at evidencing the factors explaining the variations observed in fresh bark peeling rate for spruce and Douglas-fir in southern Belgium and secondly at identifying the key factors to consider when setting up a deer management plan. • Method: Fresh bark peeling rate was recorded with a systematic sampling survey from 2004 to 2007. The covered territory was then divided into 63 distinct hunting zones of area ranging from 1,000 to 25,000 ha. About 5,000 plots were monitored annually. Each zone was characterized with a large number of explanatory variables. The explanatory variables were integrated firstly into fixed linear models using a stepwise procedure, and then into a mixed model. • Results: The significant variables included in the model ( R = 44 %) are (by decreasing order of importance) red deer densities, proportion of coniferous stands and agricultural areas, snow cover, distance to urban habitats, and species diversity in the understory. • Conclusion: The models revealed the impacts of several factors on bark peeling: deer density, deer-carrying capacity of the territory, landscape structure, and severity of winter conditions. The adjusted model allowed subtracting the impact of winter conditions in order to produce a relevant indicator for hunting management. In addition, the model was used to assess the sensitivity of a forested area to bark peeling based on its environmental characteristics. [ABSTRACT FROM AUTHOR]

The grey squirrel, Sciurus carolinensis Gmelin, was introduced into sites in England, Wales, Scotland and Ireland from the United States and Canada between 1876 and 1929. Soon after its introduction there were reports of damage to trees by seasonal bark stripping activity. Surveys in state and private forests since 1954 have monitored their distribution and impacts. Two surveys also gathered information on control efforts used to minimise damage. Grey squirrel population range has expanded significantly in Britain over the last 50 years and continues to do so. Survey results show high variability between years in damage recorded, consistent with the understanding that damage is triggered by high numbers of juveniles entering the population following a good breeding season. Results also show high variability between tree species in levels of damage recorded, but that thin-barked tree species are most at risk of damage from grey squirrels. Further, results show that the economic cost of damage can be high and that control measures will be ineffective if not appropriately targeted. The findings support suggestions that grey squirrels in mainland Europe should be eradicated to prevent future population expansion and any accompanying impacts on commercial timber crops. © Crown copyright 2013. Reproduced with permission of Her Majesty's Stationery Office. Published by John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In forest stands, Picea abies is commonly subjected to logging and bark stripping injuries. Most mechanical wounds do not exceed 300 cm, but their pathological consequences are unclear. The aim of the study was to estimate the rate of wound occlusion and the probability of decay in P. abies stems in relation to initial wound size and wounding season. The study included forty-five stems with 1-, 2-, 3-, 4- and 5-cm-wide by 15-cm-long wounds (15-75 cm), and eighty-three stems with 15-cm-wide by 20-cm-long wounds (300 cm), made either in January or in August. After 19-21 years, each wound was assessed for occlusion rate and the presence of decay. All 1- to 2-cm-wide wounds were occluded, compared to 58-70% of the 3- to 4-cm-wide wounds, 25% of the 5-cm-wide wounds, and 0% of the 15-cm-wide wounds. On average, it took 3.6, 5.5, 10.4, 12.7 and 14.7 years to occlude wounds ranging in size from 1- to 5-cm-wide, respectively. After 21 years, the observed size of wounds comprising an initial area of 300 cm ranged between 14 and 481 cm. Wounding season and stem DBH had no impact on wound healing. Wound decay incidence correlated positively with the initial width of injury ( r = 0.925; P < 0.05). All 1- to 2-cm-wide wounds lacked any decay, while the proportions of decay among 3-, 4-, 5- and 15-cm-wide wounds were 58.3, 50.0, 83.3 and 100%, respectively. Length of decay comprised 35-225 cm. Consequently, wounds on P. abies stems greater than 5 cm width are unlikely to be occluded and more prone to decay development. [ABSTRACT FROM AUTHOR]

Abstract: Bark is a greatly coveted non-timber forest product (NTFP). Its overexploitation from medicinal tree species threatens an essential source of medication for rural populations. Despite the relevance of bark, not much information is available on the ecological impact of bark harvesting. In Benin, West Africa, we investigated how various harvesting techniques affect the bark re-growth of 12 tree species and the survival of debarked trees. Trees were debarked following a combination of three factors: (i) season of bark harvesting (dry or rainy season), (ii) size class of the tree (three stem diameter classes) and (iii) intensity of debarking (seven different percentages of trunk circumference debarked). Measurements of edge growth and survival were taken every 6months during 2years. Ring-barking (100% of trunk circumference debarked) did not allow the sustainable exploitation of any species, while all trees with 75% of debarked circumference remained alive and produced edge growth. Whatever the bark harvesting technique, 5 out of the 12 species had a bark recovery rate below 1cm/year, rendering the wound closure very unlikely. On the other hand, five species showed good to very good bark recovery rates (>7cm/year) and for these species the combination of debarking factors (season, dbh and intensity) allowing the highest edge growth was determined. This experimental bark stripping revealed the complexities involved in decision-making for sustainable tree management. Studying the patterns of bark recovery rates provides a relevant tool to assess for each species the delay for achieving closure of a specific wound area. [ABSTRACT FROM AUTHOR]

For 345 stands of deciduous hardwood forest in Hyogo Prefecture, Western Japan, we assessed the decline of shrub-layer vegetation due to sika deer in each stand by using the shrub-layer decline rank (SDR), determined by combining the shrub-layer vegetation cover and the presence of signs of grazing by sika deer in a stand. Since there was a geographical correlation between SDR and sighting per unit effort (SPUE), which is an index of the relative density of sika deer, it appeared that decline of shrub-layer vegetation in a stand can be accurately evaluated by SDR. There were correlations between SDR and several variables that indicate the status of components in forests (presence of saplings of tall trees, occurrence of bark stripping of tall trees, proportion of bark-stripped stems of Clethra barvinervis, decline of subtree-layer vegetation by bark stripping, cover of litter on the ground, and area of soil surface erosion). These results indicate that the status of these components changes with decline of shrub-layer vegetation by sika deer grazing. It is thought that such synchronizations are caused by sika deer grazing or a direct or indirect effect by decline of shrub-layer vegetation due to sika deer. Therefore, it is reasonable to assess decline in physical structure due to sika deer for stands of deciduous hardwood forests according to SDR. [ABSTRACT FROM AUTHOR]

• European bison was the most important debarking agent. • Severe debarking occurred in stands located closer to feeders. • Severe debarking occurred in stands with open canopies. • Coniferous stands were most frequently debarked. • Wisent can debark older trees than deer species. The damage to trees that is caused by ungulate species is a natural result of their presence in ecosystems. High densities of ungulates may have a negative effect on biodiversity and the regeneration and survival of trees. The aim of this study was to identify the factors that affect the probability of the occurrence of damage in forest stands as a result of the presence of European bison (Bison bonasus). We collected data on the presence of European bison in given locations in winter and spring of 2020; this data also concerned damage to trees, forest stand characteristics, and densities of other ungulates. European bison was the most important debarking agent. Within the home range of the European bison, 344 forest stands were damaged, which represented 43.5% of all stands. The most frequent damage was bark stripping, 35.9%. The most important factors in terms of bark damage were canopy cover, dominating tree species, dominating tree age, and distance to a feeder. More debarking occurred in stands with open canopies, and coniferous species were more likely to be damaged than broadleaved species. Frequency of damage in forest stands with dominating Norway spruce was higher than 0.5, whereas for forest stands with silver fir and Scots pine it was over 0.4. Other coniferous species also presented a relatively high proportion of damage (0.38). The results of our study indicate a need for rational damage-prevention measures in the ranges of other free-living wisent populations that live in managed forests. [ABSTRACT FROM AUTHOR]