Tree Damage Research Articles

Canopy gap patterns in Mediterranean forests: a spatio-temporal characterization using airborne LiDAR data

ContextIn the last century European forests are experiencing tree damage and mortality rise and it is expected to continue due to increased disturbances under global change. Disturbances generally creates canopy gaps, which leads to secondary succession, compositional changes and landscape mosaic transformations. Forest gap characterization has traditionally been performed in light-limited tropical and boreal forests, but no studies have been found on water-limited Mediterranean forests. Characterising canopy gaps and their dynamics in Mediterranean forests will help to better understand their dynamics across landscapes under ongoing global change.ObjectivesWe aimed to characterize canopy gaps and quantify their dynamics identifying hotspots of openings and closings in Mediterranean forests.MethodsWe used low density multitemporal airborne LiDAR data between 2010 and 2016, over a large region (Madrid, Spain, 1732.7 km2) with forests ranging from monospecific conifer and broadleaved to mixed forests, to delineate canopy gaps. The characterization was made through its Gap Size Frequency Distribution (GSFD) by forest type and year. We analysed canopy gap dynamics and identified statistically significant hotspots of gap openings and closings in each forest type.ResultsThere were major differences between conifers and broadleaved forest in terms of gap characteristics and GSFD. In general, we found a great dynamism in Mediterranean forests with high rates of forest openings and closings, but a net closing trend. A high spatial heterogeneity was observed finding hotspots of gap openings and closings across the entire study area.ConclusionsWe characterised for the first-time large-scale structure and dynamics of canopy gaps in Mediterranean forests. Our results represents the characterisation of the GSFD of Mediterranean forests and could be considered a benchmark for future studies. The provision of up-to-date periodic maps of hotspots of gap opening, closing and net change help to understand landscape mosaic changes as well as to prioritise forest management and restoration strategies.

Predictors of tropical cyclone-induced urban tree failure: an international scoping review

BackgroundTrees are critical components of rural and urban ecosystems throughout the world. While they have adapted to the historic conditions of their native environments, climate change, urbanization, and human-assisted range expansion may test the storm resiliency of many tree species.ObjectiveIn this global multilingual scoping review, we investigate a range of intrinsic (i.e., tree characteristics) and external (i.e., environmental and management) factors which have been used to predict tree failure during tropical cyclones.DesignWe searched online databases and journals in English, Chinese, French, Japanese, Portuguese, and Spanish to find peer-reviewed papers and dissertations. We retained papers that used ground-based methods to study tree damage following a tropical cyclone and conducted a statistical analysis of factors that influence tree resistance to damage. From each paper we extracted details of study methods, and the relationships between damage and predictors.ResultsOur efforts generated 65 peer-reviewed papers and dissertations that met our final criteria for inclusion (i.e., data on the relative proportion of trees failed/intact as assessed no more than a year after the storm event). Of these papers 37 independent variables were assessed to predict tree failure. Research in both urban and rural settings tends to be concentrated in regions frequently impacted by tropical cyclones. Characteristics of species such as wood density have been studied in rural environments and are also relevant predictors for tree failure in urban trees. Environmental characteristics unique to urban settings such as planting areas surrounded by pavement need further research. Several urban studies demonstrate that risk assessment methods can predict tree failure during a storm.ConclusionResults can be used by future storm researchers to identify both predictors may warrant inclusion in their models as well as predictors which have yet to be tested. Results can also inform planning and activities that can mitigate tropical cyclone damage to the urban forest.

Insect wood borers on commercial North American tree species growing in China: review of Chinese peer-review and grey literature.

Invasive insect wood borers are a threat to global forests and tree-related industries as they can damage trees and spread plant pathogens. Reports of damages by wood borers on plants that were planted overseas may facilitate the identification of potential invaders and speed up risk assessment. However, much of this information remains unavailable to the international plant protection community due to language barriers, lack of digitization, or limited circulation of regional literature. Here, we investigated reports of wood borers on 7 important North American commercial tree species planted in China (Carya illinoinensis, Liquidambar styraciflua, Pinus elliottii, Pinus taeda, Quercus texana, Quercus rubra, and Quercus virginiana) in peer-reviewed as well as "grey" (nonpeer-reviewed) Chinese literature. A total of 60 unique wood borer records were found, yielding reports of 4 orders, 39 genera, and 44 species of insect wood borers. Among Coleoptera, longhorned beetles (Cerambycidae) were the most commonly reported colonizers of North American trees in China. Chinese peer-reviewed reports of pests on alien plants are a valuable tool to survey for potential wood-boring invaders of North America, and wherever North American trees are planted and have the potential to encounter Asian invasive insects. Digitization and dissemination of non-English literature are essential for contemporary risk assessment. On the other hand, the nonpeer reviewed "grey" literature, primarily agency reports and student theses, provided only 5% of the records; many incidental observations were unreliable.

Recovering the urban forest: The role of trees, tree culture, and place attachment before and after Hurricane Harvey

Trees can be powerful symbols that contribute to the production and consumption of places. Disaster events, such as hurricanes, alter the physical landscape, causing tree damage and loss. In places with strong tree cultures, the reforestation of damaged landscapes becomes an implicit element of recovery plans; however, less is known about the implications of tree loss to community recovery. In 2017, Hurricane Harvey made landfall near the coastal communities of Rockport and Fulton, Texas. Rockport-Fulton, known for its beach tourism, is home to a remnant live oak (Quercus virginiana) forest shaped by coastal onshore winds. Many of Rockport-Fulton’s windswept oaks were damaged or lost along with native and non-native palm trees. Rockport-Fulton’s history is imbued with stories situated around its oak forest. Drawing from multiple sources and participant observations from repeated site visits, we analyzed references to Rockport-Fulton’s trees in news media, organizational communications, and public exhibits before and after Harvey to understand the area’s tree culture and its associated discourses. We also interviewed tourists, business owners, and community members nine months after Harvey to understand their perceptions of recovery efforts. Our findings show that tree narratives pre- and post-Harvey amplify social-ecological systems definitions of resilience and that tree loss was a dominant theme in the recovery process for all participants. Yet we also found that tourists discussed the damage to palm trees, whereas community members focused on the loss of live oaks. Despite these preferences, trees available through replanting efforts contained few live oak and palm species; furthermore, recovery plans did not amplify trees in recovery strategies. Overall, our findings highlight the importance of replanting trees during the disaster recovery process in a way that not only enhances local biodiversity but also reaffirms place characteristics to meet community members’ and visitors’ expectations.

Dynamic response and breakage of trees subject to a landslide-induced air blast

Abstract. Landslides have been known to generate powerful air blasts capable of causing destruction and casualties far beyond the runout of sliding mass. The extent of tree damage provides valuable information on air blast intensity and impact region. However, little attention has been paid to the air blast–tree interaction. In this study, we proposed a framework to assess the tree destruction caused by powerful air blasts, including the eigenfrequency prediction method, tree motion equations and the breakage conditions. The tree is modeled as a flexible beam with variable cross-sections, and the anchorage stiffness is introduced to describe the tilt of the tree base. Large tree deflection is regarded when calculating the air blast loading, and two failure modes (bending and overturning) and the associated failure criteria are defined. Modeling results indicate that although the anchorage properties are of importance to the tree eigenfrequency, tree eigenfrequency is always close to the air blast frequency, causing a dynamic magnification effect for the tree deformation. This magnification effect is significant in cases with a low air blast velocity, while the large tree deflection caused by strong air blast loading would weaken this effect. Furthermore, failure modes of a specific forest subject to a powerful air blast depend heavily on the trunk bending strength and anchorage characteristics. The large variation in biometric and mechanical properties of trees necessitates the establishment of a regional database of tree parameters. Our work and the proposed method are expected to provide a better understanding of air blast power and to be of great use for air blast risk assessment in mountainous regions worldwide.

Time course of inducibility of indirect responses in an ant-defended plant.

Plants have evolved inducible defenses that allow them to minimize costs associated with the production of constitutive defenses when herbivores are not present. However, as a consequence, some plants might experience a period of vulnerability between damage and the onset of defense and/or between the cessation of damage and relaxation of defense. Few studies have examined the time course in the inducible protective mutualism between ants and extrafloral nectary (EFN)-bearing plants. None has compared the inducibility of EFNs on vegetative versus reproductive parts or in response to different levels of herbivore damage. Here, we disentangle the inducibility process by evaluating extrafloral nectar production and ant attendance over time, the time course of inducibility on different plant parts, and the time course of inducibility in response to different levels of foliar damage in a Brazilian tree, Qualea multiflora (Vochysiaceae). Using simulated herbivory on leaves and flowers, we found that (a) the production of extrafloral nectar from foliar and floral EFNs, as well as ant attendance, exhibited a lag between the moment of damage and the peak of response, followed by a response peak (usually 24 h after damage) at which the defense remains at its maximum level, then declines to prestimulus levels; (b) the time course of inducibility and the peak activity did not differ between EFNs located in vegetative versus reproductive parts, except for sugar concentration, which was higher in EFNs on vegetative parts; and (c) the time course of inducibility of foliar EFNs depended on damage level. Although considered a cost-saving strategy, inducible defenses can be disadvantageous since they can leave plants vulnerable to attack for extended periods. Our results illuminate the dynamics of the induced response and the underlying mechanisms that might mediate it, ultimately providing new insights into defense strategies employed by plants.

Do the foraging strategies of Odontotermes horni (Wasmann)workers on various organic matter depend on the weather parameters?

The investigation delved into how worker termites of O. horni search for food sources under varying weather conditions in an undisturbed forest ecosystem. The result indicated that the maximum atmospheric temperature had a significant negative correlation with foraging patches < 25 cm. The minimum atmospheric temperature exhibited a significant negative correlation with tree damage and the height of earthen sheeting construction by the termite workers. Moreover, the maximum atmospheric relative humidity showed a significant negative correlation with tree damage and the height of earthen sheeting by the workers. Similarly, the minimum atmospheric relative humidity had a significant negative relationship with tree damage and the height of earthen sheeting construction by the workers, but a positive significant relationship with foraging patches < 25 cm. Lastly, rainfall had a significant negative relationship with tree damage and the height of earthen sheeting on the trees, while sunshine hours showed a significant positive relationship with tree damage by the workers.

Lianas increase lightning-caused disturbance severity in a tropical forest.

Lightning is an important agent of plant mortality and disturbance in forests. Lightning-caused disturbance is highly variable in terms of its area of effect and disturbance severity (i.e. tree damage and death), but we do not know how this variation is influenced by forest structure and plant composition. We used a novel lightning detection system to quantify how lianas influenced the severity and spatial extent (i.e. area) of lightning disturbance using 78 lightning strikes in central Panama. The local density of lianas (measured as liana basal area) was positively associated with the number of trees killed and damaged by lightning, and patterns of plant damage indicated that this occurred because lianas facilitated more electrical connections from large to small trees. Liana presence, however, did not increase the area of the disturbance. Thus, lianas increased the severity of lightning disturbance by facilitating damage to additional trees without influencing the footprint of the disturbance. These findings indicate that lianas spread electricity to damage and kill understory trees that otherwise would survive a strike. As liana abundance increases in tropical forests, their negative effects on tree survival with respect to the severity of lightning-related tree damage and death are likely to increase.

Occurrence of brown root rot in Ocean Expo Park, Okinawa, Japan: Infection route and preventive control measures

AbstractOcean Expo Park, established in 1976 on subtropical Okinawa Island, Japan, has approximately 8000 planted or naturally grown trees in an area of 77.2 ha. Windfall of these trees occurs mainly due to typhoons; wood chips made from the trunks and roots of windfall trees are commonly used as mulching material throughout the park areas, despite possible infection by pathogenic fungi such as Phellinus noxius, the pathogen causing brown root rot. P. noxius is distributed in tropical and subtropical areas worldwide and has a broad host range. The fungus can infect host plants with mycelia via root‐to‐root contact or with basidiospores. Here, we report the current status of tree damage caused by brown root rot in the park and infer the infection routes of P. noxius based on microsatellite markers. Among a total of 294 trees surveyed in the park, P. noxius was isolated from 13 trees of five species. P. noxius was observed more frequently on Ficus microcarpa than on other tree species. Ficus superba var. japonica was identified as a new host species, and Bombax ceiba was first recorded as a host plant of P. noxius in Japan. Among the 13 P. noxius isolates from the diseased trees, 2 isolates from adjacent diseased trees were considered to be of the same genet, while the other 11 isolates were different genets, indicating that infection by basidiospores occurred frequently among trees in the entire park, although spread via root systems also occurred between at least two adjacent trees. An identical genet was not detected at distant locations, which suggests that the disease does not spread via chips. However, mulching with chips can lead to wood decay due to decaying fungi other than P. noxius. Therefore, in accordance with the precautionary principle, the park currently prohibits the chipping and mulching of windfall or damaged trees and is considering disposal methods such as burning.

Analysis of Tree Health in the Pematangsiantar Animal Park, North Sumatra Province

This study aims to determine acquire data on the species composition and structure of trees, as well as to analyze the health of trees growing in the Pematangsiantar Animal Park. Using the census approach, data collection was conducted. The health state of trees was determined using the Forest Health Monitoring (FHM) method, which measures tree health by categorizing the kind and severity of damage per every plant. Two indicators are utilized to measure tree health: tree damage and tree crown condition. The method of data collection was conducted on trees with a minimum diameter of 20 centimeters. Techniques of data analysis consisting of descriptive and weighted scoring. At the Pematangsiantar Animal Park, there are 49 species of trees and a total of 153 unique trees. Mahogany (Swietenia mahagoni) is the most prevalent tree species, with 21 specimens. The health state of the trees in the Pematangsiantar Animal Park included 48 trees with a healthy status, 93 trees with bad (unhealthy) status, and 12 trees with a sick status, however none were discovered to be in a very sick condition

Differentiating effects of salvage logging and recovery patterns on post-fire boreal forests in Northeast China using a modified forest disturbance index

ABSTRACT Forests are resilient to a range of disturbances, but combinations of severe natural and anthropogenic disturbances (e.g. wildfire and logging) may inhibit forest recovery and lead to forest degradation. Recent studies have explored long-term forest-disturbance detection and forest-recovery dynamics by using free and open-access remote-sensing images. However, mapping consecutive multiple disturbance agents is challenging using existing automated change-detection algorithms because the reduced canopy reflectance and the smoothing of consecutive disturbance signals mean that the initial disturbance cannot be spectrally separated from the second disturbance. Furthermore, uncertainty remains about post-disturbance vegetation dynamics and the effects of forest recovery under the interaction of burn severity, biological-legacy management, and active forest restoration (i.e. artificial regeneration and assisted natural regeneration). This contributes to biases in long-term forest-recovery monitoring, which are not conducive to the guidance of post-fire vegetation recovery. Here, we propose a modified disturbance index to separate the spectral characteristics of fire and forest logging using normalized tasseled-cap components (brightness and wetness) and detect the spatiotemporal distribution of post-fire logging by means of an index threshold and image differencing. On this basis, the recovery patterns of the post-fire forest are differentiated by considering the cumulative effect of fire, post-fire logging, and recovery approaches. The method is tested in the burn areas of the 5.6 Fire in the Greater Hinggan Mountain area (the largest forest fire in recorded history in China), giving an overall accuracy of 85% in post-fire forest logging mapping. Our results confirm that biological legacies (i.e. trees, logs, and snags) were removed across many areas in the fire, with activities peaking in the second year after the fire and located chiefly in areas of moderate and high burn severity. By identifying post-fire logging, the fluctuation and high disturbance index of the conventional temporal trajectory in the early stage of forest recovery are explained. The large-scale salvage logging slowed the recovery of the post-fire forest ecosystem and influenced the recovery process through the interaction of burn severity and active forest restoration. In areas of high burn severity, assisted natural regeneration (i.e. natural regeneration with artificial aids such as clearing the snags, weeding, digging pits, and supplemental planting) preserved biological legacies and achieved a higher proportion of forest recovery, second only to non-logged areas where natural regeneration (i.e. forestry recovering naturally without any artificial intervention) occurred. By contrast, salvage logging followed by artificial regeneration (i.e. clear-cutting all dead or damaged trees followed by tree planting or artificial seeding) hindered vegetation recovery in the early stage, but it improved the recovery rate in years 10–20 and approached the recovery proportion of non-logged areas where natural regeneration occurred as the recovery progressed and habitat conditions improved. The proposed method is shown to offer important advantages in detecting post-fire salvage logging, and it provides improved guidance for forest managers in developing strategies for forest recovery.

Integrated pest management of Hypsipyla robusta shoot-tip borer (Lepidoptera: Pyralidae) in Chukrasia tabularis (Sapindales: Meliaceae).

Chukrasia tabularis A. Juss produces a valuable timber but plantations are susceptible to attack by the shoot-tip borer Hypsipyla robusta Moore. An integrated pest management (IPM) approach is desirable to limit the extent of damage. Therefore, this study was undertaken to evaluate the deployment of IPM measures in plantations in Vietnam. Data on tree damage and the biology of H. robusta were gathered in 4 provinces over one year and used to build an investigation schedule. Two preliminary IPM trials were then established in which Bacillus thuringiensis and Metarhizium anisopliae were applied to the foliage when the damage incidence (P%) was in the range 5-10%; and insecticides (Carbaryl, Carbosulfan) were applied when the P% exceeded 10%. In addition, larvae and pupae were removed manually over time. In the first trial, the combination of manual and biological control methods reduced the damage index (DI) of trees from 4 tolerant families by 82% compared to the untreated control plots. In the second trial using standard planting stock, application of insecticides was required to reduce the DI by 83%. Six extended IPM trials were undertaken using the same IPM protocols and these reduced the DI to the same extent as in the preliminary trials. Over an 18-month period, the deployment of IPM increased height growth by 19-22% and diameter growth by 38-41% compared to the controls. These findings highlight the value of planting improved seed and the benefit of adopting an IPM approach to manage the shoot-tip borer.

Orientus ishidae (Hemiptera: Cicadellidae): Biology, Direct Damage and Preliminary Studies on Apple Proliferation Infection in Apple Orchard.

The mosaic leafhopper, Orientus ishidae (Matsumura), is an Asian species widespread in Europe that can cause leaf damage in wild trees and transmit disease phytoplasmas to grapevines. Following an O. ishidae outbreak reported in 2019 in an apple orchard in northern Italy, the biology and damage caused by this species to apples were investigated during 2020 and 2021. Our studies included observations on the O. ishidae life cycle, leaf symptoms associated to its trophic activity, and its capability to acquire "Candidatus Phytoplasma mali," a causal agent of Apple Proliferation (AP). The results indicate that O. ishidae can complete the life cycle on apple trees. Nymphs emerged between May and June, and adults were present from early July to late October, with the peak of flight between July and early August. Semi-field observations allowed for an accurate description of leaf symptoms that appeared as a distinct yellowing after a one-day exposure. In field experiments, 23% of the leaves were found damaged. In addition, 16-18% of the collected leafhoppers were found carrying AP phytoplasma. We conclude that O. ishidae has the potential to be a new apple tree pest. However, further studies are required to better understand the economic impact of the infestations.

Modeling Tree Damages and Infrastructure Disruptions under Strong Winds for Community Resilience Assessment

Tree failures under extreme gusts could exacerbate storm damages to critical infrastructures, including the power delivery system, transportation network, or residential buildings. Nevertheless, the effects of tree damages have largely been excluded in existing community resilience assessment frameworks. To this end, presently, a model integrating tree failure consequences with community-level resilience evaluation is proposed for improved damage and recovery projections, considering the interconnected transportation, power delivery, and residential building systems. Tree failure probabilities are estimated based fragility analysis of the tree structural response under gusts. Proximity analysis is conducted to quantify the threat of trees striking critical infrastructures. The tree and wind risk assessments are integrated with fragility analysis of the power distribution system timber utility poles and the vulnerability analysis of low-rise wooden residential buildings. The methodology is carried out on a case study of a community in the northeastern US. The results indicate utility pole failures and roadway debris accumulations and blockages initiate when wind speeds reach around 40 m/s (90 mi/h). Although the inclusion of tree failures increase pole failure probability failure, tree-induced damages to residential buildings were found minimal due to the relatively lower heights of the sparser trees in the studied suburban region. Storm impacts are linked to the household level, including structural damages and their restoration times, increases in travel time to the main road, and probability of losing power. Vegetation management strategies are found to effectively reduce the building and powerline damages and debris buildup on roads.

Value ‘generalisation’ in ecosystem accounting - using Bayesian networks to infer the asset value of regulating services for urban trees in Oslo

In this paper, we demonstrate value generalisation from a sample of ecosystem assets – municipally managed trees - to all tree assets within an urban ecosystem accounting area. A Bayesian network model is used to machine-learn non-parametric correlation patterns between biophysical site condition variables and output variables of an ecosystem service model – here iTree Eco for modelling the regulating services of urban forests. The paper also demonstrates the use of spatial Bayesian network modelling to quantify the reliability of value generalisation for accounting purposes. Value generalisation entails inferring ecosystem service values for all locations in an ecosystem accounting area, where the accounting practitioner has less information about the asset and its context, than in an available sample of managed sites within the accounting area. The modelling is carried out as a “proof-of-principle” of potential value generalisation and uncertainty analysis methods for ecosystem accounting. It does not cover all regulating ecosystem services of urban forests, nor cultural services. While noting that wide confidence intervals for generalised values pose challenges for using monetary accounts for the accounting purpose of change detection, we find that tree-specific asset valuation is possible in an urban accounting setting. Our findings serve the purpose of raising awareness about asset values of urban green infrastructure, to bring them more on a par with grey infrastructure in urban planning. We also argue that the reliability of the asset value of individual trees is also good enough to be used for non-accounting purposes, such as municipal tree damage assessments.

Graffiti Paint on Urban Trees: A Review of Removal Procedures and Ecological and Human Health Considerations

Mature trees play a fundamental role in nature and are crucial to maintaining good air quality in the urban ecosystem where they reduce air pollution, lower the surface temperature, and emit medicinal volatile organic compounds which combine to improve human health and mental wellbeing. From an aesthetic and cultural point of view, they are true living monuments to be preserved. In both rural and city environments, it takes numerous years for trees to become mature enough to have a significant impact on our health and the current global climate changes together with high levels of pollution in urban environments and other anthropic factors such as vandalism constitute important obstacles to new tree growth. This clearly makes existing trees, especially old growth, far more valuable than we often realize. Regardless of their artistic quality and in some instances their positive messages, graffiti are still unacceptable on living organisms, especially older urban trees. They also have a significant environmental impact due to the emissions related to graffiti that are primarily based on anthropogenic volatile organic compounds (VOCs) which contribute to the formation of ground-level ozone. We reviewed the literature on graffiti and paintings applied on tree bark and ultimately found that oil-based paints in particular can damage tree life support systems. We herein also discuss graffiti prevention, the potential impact on human health related with graffiti removal, as well as methods for tree bark cleaning including, as suggested by different urban forestry specialists, the application of citrus-based products for 20–60 min before rubbing and rinsing or multiple 1–2 h treatments, in the case of recent or old graffiti, respectively.

Tree insect pests and pathogens: a global systematic review of their impacts in urban areas

Trees contribute greatly to urban environments and human well-being, yet relatively little is known about the extent to which a rising incidence of tree insect pests and pathogens may be affecting these contributions. To address this issue, we undertook a systematic review and synthesis of the diverse global empirical evidence on the impacts of urban tree insect pests and pathogens, using bibliographic databases. Following screening and appraisal of over 3000 articles from a wide range of fields, 100 studies from 28 countries, spanning 1979–2021, were conceptually sorted into a three-part framework: (1) environmental impacts, representing 95 of the studies, including those reporting on tree damage, mortality, reduced growth, and changes in tree function; (2) social impacts were reported by 35 of studies, including on aesthetics, human health, and safety hazards; and (3) economic impacts, reported in 24 of studies, including on costs of pest management, and economic losses. There has been a considerable increase in urban impact studies since 2011. Evidence gaps exist on impacts on climate-regulating capacity, including temperature regulation, water retention, soil erosion, and wind protection, but also on specific hazards, nuisances, human well-being, property damages, and hazard liabilities. As a knowledge synthesis, this article presents the best available evidence of urban tree insect / pathogen impacts to guide policy, management and further research. It will enable us to better forecast how growing threats will affect the urban forest and plan for these eventualities.

Microcapsule-Based Autonomous Self-Healing of Electrical Damage in Dielectric Polymers Induced by In Situ Generated Radicals.

Dielectric polymers are playing important roles in electrical and electronic industries. However, aging under high electric stress is a main threat to the reliability of polymers. In this work, we demonstrate a self-healing method for electrical tree damage based on radical chain polymerization, which is initiated by in situ radicals that are generated during electrical aging. Acrylate monomers contained in microcapsules will be released and flow into hollow channels after the capsules are punctured by electrical trees. Autonomous radical polymerization of the monomers will heal the damaged regions, which is triggered by radicals resulting from polymer chain scissions. After optimizing the healing agent compositions by evaluating their polymerization rate and dielectric properties, the fabricated self-healing epoxy resins showed effective recovery from treeing in multiple aging-healing cycles. We also expect the great potential of this method to heal tree defects autonomously without the need to switch off operating voltages. This novel self-healing strategy will shed light on building smart dielectric polymers with its broad applicability and online healing competence.

Widespread stem snapping but limited mortality caused by a category 5 hurricane on the Caribbean Island of Dominica

Hurricanes are projected to increase in frequency and severity over the coming century, and predicting the effects of strong hurricanes on forest communities requires an understanding of the damage patterns caused to individual trees and what drives those damage patterns. To better understand damage patterns caused by a category 5 hurricane, we censused nine permanent vegetation plots across the island of Dominica, West Indies, nine months after Hurricane Maria took a direct path over the island. We measured size, damage, and mortality for all adult trees, and measured wood density and carbon content for the 44 most common species to calculate biomass and carbon relocation from the hurricane. Despite widespread major tree damage (76% of trees), mortality nine months after the hurricane was relatively low (10% of trees). The most common damage types were stem snapping (40% of trees) and major branch damage (26% of trees), but the damage types with the highest rates of mortality were uprooting and being crushed by a neighboring tree (33% and 47% of uprooted and crushed trees died, respectively). Larger individual trees and species with lower wood density were more susceptible to snapping, uprooting and mortality, and trees on steeper slopes were more prone to being crushed by neighboring trees. Hurricane Maria caused an average loss of 44 Mg ha−1 of aboveground carbon and 90.3 Mg ha−1 of aboveground biomass. Synthesis – Trees in these hurricane-prone forests show a strong ability to survive extremely strong storms even when severely damaged, but substantial amounts of forest carbon are redistributed to the forest floor even when mortality rates are relatively low. Our data suggest that these hurricane-prone forests will continue to shift toward smaller, high wood-density species with increasing hurricane frequency and intensity.

Woodboring Beetle (Buprestidae, Cerambycidae) Responses to Hurricane Michael in Variously Damaged Southeastern US Pine Plantations

Abstract In October 2018, catastrophic Hurricane Michael caused $1.7 billion in damage to standing timber in Florida, USA. To inform recovery efforts, varying levels of damaged (low, moderate, and high) slash pine (Pinus elliottii Engelm) stands were sampled for woodboring beetles (Coleoptera: Buprestidae; Cerambycidae). These beetles generally colonize stressed and damaged trees, and their larval tunneling activities reduce the value of timber salvaged post disturbance. From 2019 to 2020, 3,810 adults of 32 species were trapped. Acanthocinus obsoletus Olivier and Monochamus sp. complex (M. titillator Fabricius; M. carolinensis Olivier) comprised 86% of all catches. Approximately 50% and 60% more woodborers, especially Monochamus sp., were trapped in moderate-damage stands in 2019 than in high- and low-damage stands, respectively. This trend was not present in 2020. From 2019 to 2020, total catches increased by ~29%, reflected by increases in Monochamus sp. and Xylotrechus sagittatus Germar. In 2019, high-damage stands had the greatest species richness, followed by low- and moderate-damage stands. Species composition in 2019 did not differ among variously damaged stands, but was more heterogeneous in low-damage than high-damage stands in 2020. Results indicate that timely salvage harvesting of moderate- and high-damage stands after catastrophic wind disturbances may lower the economic impacts by subcortical woodboring beetles.