台风和树木倒塌

Urban trees in a densely populated environment may pose risks to the public’s safety in terms of the potential danger of injuries and fatalities, loss of property, impacts on traffic, etc. The biological and mechanical features of urban trees may change over time, thereby affecting the stability of the tree structure. This can be a gradual process but can also be drastic, especially after typhoons or heavy rainstorms. Trees may fall at any time with no discernible signs of failure being exhibited or detected. It is always a challenge in urban tree management to develop a preventive alert system to detect the potential failure of hazardous urban trees and hence be able to have an action plan to handle potential tree tilting or tree collapse. Few studies have considered the comparison of tree morphology to the tilt response relative to uprooting failure in urban cities. New methods involving numerical modeling and sensing technologies provide tools for an effective and deeper understanding of the interaction of root-plate movement and windstorm with the application of the tailor-made sensor. In this study, root-plate tilt variations of 889 trees with sensors installed during Typhoon Higos (2020) are investigated, especially the tilting pattern of the two trees that failed in the event. The correlation of tree response during the typhoon among all trees with tilt measurements was also evaluated. The results from two alarm levels developed in the study, i.e., Increasing Trend Alarm and Sudden Increase Alarm indicated that significant root-plate movement to wind response is species-dependent. These systems could help inform decision making to identify the problematic trees in the early stage. Through the use of smart sensors, the data collected by the alert system provides a very useful analysis of the stability of tree structure and tree health in urban tree management.

… A four-level likelihood of tree failure … five failure trees in Hong Kong, which had been constantly monitored lasting from ∼1 month to ∼22 months before their final failure during typhoons…

Background Trees 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. Objective In 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. Design We 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. Results Our 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. Conclusion Results 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.

… When the compression stress in the stem exceeds the compressive strength, failure, will occur even if the standing tree appears to be undamaged. Indeed, this is supported by the …

… typhoon in an urban green area dominated by Japanese elm. We measured the height of failure … that this fungus had penetrated the tree via stem wounds, thereby causing stem failure. …

… 0.49 major typhoons annually, and compared their resistance and resilience to those of forests in other regions. Typhoons cause remarkably few tree falls at FEF; multiple typhoons in …

Practitioners who assess the risk associated with urban trees often factor in the presence or absence of visual tree defects when determining whether a tree may fail. Although these defects are a main fixture in many tree risk assessment systems and best-management practices, the research supporting their usefulness in predicting tree failure during storms is limited. When looking at past research involving populations of storm-damaged trees, several defects have never predicted failure (or have been associated with reduced rates of failure). In this study, we took a closer look at four such defects: codominant branches; branch unions with included bark; multiple stems originating from the same point; and overextended branches. After Hurricane Ian, we revisited 1518 risk-assessed trees where one of these four defects was identified as the primary condition of concern. Fourteen of these trees experienced branch failure during the storm (which hit the study area as a downgraded tropical storm). Upon closer inspection, none of these failures occurred at the defect of concern. Our findings indicate that none of the defects assessed appeared to increase the likelihood of tree failure in the species tested. Our results are in line with past research on these defects derived from post-storm assessments and analysis.

… Typhoons significantly damage the urban forest ecosystem, especially impacting … tree roots. Three prominent ecosystem disservices from natural disasters are identified: power failures, …

Summary Tropical cyclones (TCs) sporadically cause extensive damage to forests. However, little is known about how TCs affect forest dynamics in mountainous terrain, due to difficulties in modelling wind flows and quantifying structural changes. Typhoon Mangkhut (2018) was the strongest TC to strike Hong Kong in over 40 yr, with gusts > 250 km h−1. Remarkably, the event was captured by a dense anemometer network and repeated LiDAR surveys across natural forests and plantations. We mapped long‐term mean and extreme wind speeds using CFD models and analysed corresponding changes in canopy height, which uncovered TC‐forest dynamics at unprecedented scales (> 400 000 pixels, 1108 km2). Forest height was more strongly limited by wind exposure than by background topography, a limitation attributable to a dynamic equilibrium between growth and disproportionate TC damage to taller forests. Counterintuitively, wind‐sheltered forests also suffered heavy damage. As a result, canopies of wind‐sheltered forests were more rugged, which contrasted with flat‐topped forests at wind‐exposed sites. Plantations were more susceptible to TCs compared to natural rainforests of similar stature (canopy height change −0.86 m vs −0.39 m). Our findings highlight TCs as important, often overlooked factor that fundamentally shapes forest structure and dynamics.

Urban trees are often more sun- and wind-exposed than their forest-grown counterparts. These environmental differences can impact how many species grow–impacting trunk taper, crown spread, branch architecture, and other aspects of tree form. Given these differences, windthrow models derived from traditional forest production data sources may not be appropriate for urban forest management. Additionally, visual abnormalities historically labeled as “defects” in timber production, may not have a significant impact on tree failure potential. In this study, we look at urban tree failures associated with Hurricane Irma in Tampa, Florida, USA. We used spatial analysis to determine if patterns of failure existed among our inventoried trees. We also looked at risk assessment data to determine which visual defects were the most common and the most likely to be associated with branch or whole-tree failure. Results indicate that there was no spatial pattern associated with the observed tree failures–trees failed or withstood the storm as individuals. While some defects like decay and dead wood were associated with increased tree failure, other defects such as weak branch unions and poor branch architecture were less problematic.

Category 5 Typhoon Odette, internationally known as Rai, devastated the Central Philippines in December 2021, causing immense damage to the country’s infrastructure, agriculture, and ecosystems. Coastal vegetative ecosystems, which include mangroves, are exposed to strong wind and wave energy during extreme weather events. Considering their importance in providing a myriad of ecosystem services to coastal communities, the post-typhoon assessment of mangroves will serve as a guide to future rehabilitation efforts. On August 13 and 14, 2024, 8 months after Typhoon Odette, the community structure characteristics (species composition, stem density, basal area, and regeneration potential) and damage severity of planted and natural mangrove forests were assessed in eight 10x10 m permanent plots located in Bais Bay, Central Philippines. Trees inside the plots were observed for signs of damage and were ranked in terms of damage severity. The differences in damage between natural and planted stands were statistically significant at χ2=5.113; p=0.02. There was a weak association between stand type (natural or planted) and damage incidence (φ= -0.110), with reforested sites being more associated with damaged trees. Rhizophora stylosa showed low resilience, having the highest mortality rate of 15 trees, 14 of which were in planted sites. Most of the R. stylosa stands also failed to show refoliation 8 months after the typhoon, in contrast to Sonneratia alba and Avicennia marina trees which displayed refoliation as well as new stem sprouts despite also sustaining damage. Results of the study indicate that future mangrove planting projects should aim to plant a diverse set of mangrove species while following the correct species zonation of the forest (i.e., storm-resilient Sonneratia alba and Avicennia marina in seaward zones and Rhizophora in midward zones) to increase resiliency, especially in areas vulnerable to typhoons. Adequate space conducive for lateral growth should also be provided between planted trees.

Abstract Quantifying ecosystem resilience is critical for predicting how shifts in disturbance regime affect ecosystem structure and function as a result of recent climate change. Studies of disturbance-ecosystem interactions often focus on one or a few disturbance events but the interactions may vary considerably among disturbance events. We used a 25-year LAI (leaf area index) record of the Fushan Experimental Forest (FEF) of northeastern Taiwan to explore forest LAI resilience to annual typhoon disturbance. The four typhoons of 1994 caused the most dramatic change of LAI in both the magnitude and the rate, as well as the longest time for a full recovery. However, typhoons varied in their effects, and not all intense typhoons caused major impact suggesting that result derived from one or a few disturbance events is unlikely to capture the full spectrum of disturbance effect. Using LAI of 4.26 measured following a non-typical year of no typhoon occurrence as a reference, it took 11─16 years before the predicted LAI to return to the reference level, which represents the resilience (time to return) of the forest LAI under minimal typhoon effects. Using the event-based analyses, the average degree of return was 0.86, with values as low as 0.45, suggesting that the LAI of the FEF is not always able to fully recover within the inter-typhoon time period (

Urban trees support human well-being, yet their benefits must be balanced against the risk of tree failure. Here, we propose a simple quantitative approach that practitioners can use to assess and manage urban treefall risk. We developed a simple mechanical model based on readily measured trunk diameter and height to calculate a hypothetical maximum compressive stress in the trunk for a given wind speed. This stress-based index was treated as a latent variable linking the mechanical and stochastic components of our framework. We then fitted a statistical model that predicts treefall probability from the latent stress index using empirically observed treefall records from Typhoons Faxai and Hagibis (2019). Unmodeled sources of variability and other unaccounted-for factors were implicitly incorporated through statistical calibration. The fitted model showed a statistically supported association between the latent stress index and treefall probability (broadleaved tree AUC = 0.94, conifer AUC = 0.77). Using extreme value analysis, we estimated the 30-year return level of maximum wind speed at the study site and assessed treefall risk for individual trees under this scenario. The model indicated higher risk for tall non-native trees (relative to local native species) and for conifers. Although available treefall data remain limited, to our knowledge, this study is among the first to predict future treefall probability using empirically observed treefall records and to provide a quantitative framework for practitioners to manage treefall risk.

… The IoTT system includes tree motion sensors for capturing tree movement in terms of the tilt … of super typhoon Mangkhut in September 2018. In addition, trees having different failure …

Tropical cyclones are increasing in intensity and size and, thus, are poised to increase in importance as disturbance agents. Our understanding of cyclone ecology is biased towards the North Atlantic Basin, because cyclone effects do differ across oceanic basins. Cyclones have both short and long-term effects across the levels of biological organization, but we lack a scale-perspective of cyclone ecology. Effects on individual trees, such as defoliation or branch stripping and uprooting, are mechanistically linked to effects at the community and ecosystem levels, including forest productivity and stand regeneration time. Forest dwarfing via the gradual removal of taller trees by cyclones over many generations illustrates that cyclones shape forest structure through the accumulation of short-term effects over longer timescales.

… level damage and the impact of the cyclone on the most abundant tree species in each plot. … Prevailing winds are from the south-east, but tropical cyclones irregularly cross the coast …

… damage. We determined the factors associated with tree damage and 3-yr survival following Category 5 Cyclone … Previous studies in tropical cyclone-disturbed forests have not found a …

Each year, an average of 45 tropical cyclones affect coastal areas and potentially impact forests. The proportion of the most intense cyclones has increased over the past four decades and is predicted to continue to do so. Yet, it remains uncertain how topographical exposure and tree characteristics can mediate the damage caused by increasing wind speed. Here, we compiled empirical data on the damage caused by 11 cyclones occurring over the past 40 years, from 74 forest plots representing tropical regions worldwide, encompassing field data for 22,176 trees and 815 species. We reconstructed the wind structure of those tropical cyclones to estimate the maximum sustained wind speed (MSW) and wind direction at the studied plots. Then, we used a causal inference framework combined with Bayesian generalised linear mixed models to understand and quantify the causal effects of MSW, topographical exposure to wind (EXP), tree size (DBH) and species wood density (ρ) on the proportion of damaged trees at the community level, and on the probability of snapping or uprooting at the tree level. The probability of snapping or uprooting at the tree level and, hence, the proportion of damaged trees at the community level, increased with increasing MSW, and with increasing EXP accentuating the damaging effects of cyclones, in particular at higher wind speeds. Higher ρ decreased the probability of snapping and to a lesser extent of uprooting. Larger trees tended to have lower probabilities of snapping but increased probabilities of uprooting. Importantly, the effect of ρ decreasing the probabilities of snapping was more marked for smaller than larger trees and was further accentuated at higher MSW. Our work emphasises how local topography, tree size and species wood density together mediate cyclone damage to tropical forests, facilitating better predictions of the impacts of such disturbances in an increasingly windier world.

… intensity and frequency of tropical cyclones. Here, we calculated correlations between forest impacts (damaged trees and biomass loss) and the number of tropical storms or hurricanes, …

… patterns of damage and dynamics … , tropical cyclones not only cause extensive damage to trees, but also affect many aspects of the disturbed forests including individual tree growth, tree …

… Tropical Cyclone Larry was severe, as most individual trees within the forest remnants that we observed had some form of damage (ie minor damage, severe branch damage… all damage…

In the future with climate change, we expect more forest and tree damage due to the increasing strength and changing trajectories of tropical cyclones (TCs). However, to date, we have limited information to estimate likely damage levels, and nobody has ever measured exactly how forest trees behave mechanically during a TC. In 2018, a category-5 TC destroyed trees in our ongoing research plots, in which we were measuring tree movement and wind speed in two different tree spacing plots. We found damaged trees in only the wider spaced plot. Here, we present how trees dynamically respond to strong winds during a TC. Sustained strong winds obviously trigger the damage to trees and forests but inter-tree spacing is also a key factor because the level of support from neighboring trees modifies the effective “stiffness” against the wind both at the single tree and whole forest stand level.

Abstract Under scenarios of climate change the likelihood of more intensive extreme weather events like tropical cyclones is expected to increase and many tropical regions most at risk from cyclones are still developing economically. With increased urbanisation predicted over the next 20–50 years to cope with population growth, it is important that planning for urban development in these regions considers amelioration of danger, especially the impacts associated with cyclone damage. Approaches to risk management can learn a lot from past experiences with cyclonic events. The knowledge that was accumulated after the devastation of Darwin, Australia by Cyclone Tracy in 1974 provides important evidence that can contribute towards risk mitigation and disaster management in the future. Applying a mixed methods approach, this study examines historical information collected at the time of Cyclone Tracy to help understand the role of the urban forest and positioning of housing in reducing cyclone damage. It includes a review of whether the pattern of tree cover, which is influenced by geophysical and socio-cultural factors, mitigates or exacerbates cyclone damage. The results of the study show that although the relationship is complex, trees appear to have a role to play in ameliorating cyclone damage under certain conditions. This potential gain, along with the other benefits trees offer to tropical urban areas, means that trees are an important consideration for future urban planning in developing regions.

… of the tropical cyclone on savanna trees and put this in the context of tropical cyclones as … compared with historic records of tree damage owing to tropical cyclones in the north-west …

… hurricane damage to tree crowns and the subsequent increased mortality rate in this hurricane-prone tropical … Most studies are done within a few years of the impact of a cyclone …

Tropical cyclones (TCs) can have profound effects on the dynamics of forest vegetation that need to be better understood. Here, we analysed changes in forest vegetation induced by TCs using the normalized difference vegetation index (NDVI). We used an accurate historical database of TC tracks and intensities, together with the Willoughby cyclone model to reconstruct the 2D surface wind speed structure of TCs and analyse how TCs affect forest vegetation. We used segmented linear models to identify significant breakpoints in the relationship between the reconstructed maximum sustained wind speed (Wmax) and the observed changes in NDVI. We tested the hypothesis that the rate of change in damage caused by TCs to forest and recovery time would increase according to Wmax thresholds as defined in the widely used Saffir–Simpson hurricane wind scale (SSHWS). We showed that the most significant breakpoint was located at 50 m/s. This breakpoint corresponds to the transition between categories 2 and 3 TCs in the SSHWS. Below this breakpoint, damages caused to forest vegetation and the time needed to recover from these damages were negligable. We found a second breakpoint, with a sharp increase in damages for winds >75 m/s. This suggested that extremely intense tropical cyclones, which might be more frequent in the future, can cause extreme damages to forest vegetation. Nevertheless, we found high variation in the observed damages and time needed to recover for a given Wmax. Further studies are needed to integrate other factors that might affect the exposure and resistance to TCs as well as forests’ capacity to recover from these disturbances.

The heavy wind along with high rainfall of the catastrophic windstorm “Thane” cyclone cause defoliation, uprooting and snapping of stems and branches of trees in Pondicherry University Campus, Puducherry. A total of 1181 (20%) trees (>3.2 cm DBH) in Pondicherry University Campus were uprooted due to the Thane cyclone. Tree mortality (uprooted) and damage (broken) were observed more in Acacia auriculiformis than other species in response to Thane cyclone in Pondicherry University campus. In the present study, wood density did not show any significant relationship between the damage, mortality and resistance (standing with defoliation and minor branch fall). Acacia auriculiformis was more susceptible to Thane cyclone followed by Tectona grandis. However, Azadirachta indica and Mangifera indica were observed more resistance to thane cyclone. The greater uprooting in introduced plantation species such as Acacia auriculiformis and Tectona grandis was higher than native species Azadirachta indica and Mangifera indica which could be attributed to spread their roots in the surface soil and they do not penetrate deeper into the soil .

… This paper reports on the results of a survey of the type and suspected cause of damage to garden trees in Darwin during Cyclone Tracy, as well as observations on their recovery and …

Windstorms may have negative consequences on forest ecosystems, industries, and societies. Extreme events related to extra-tropical cyclonic systems remind us that better recognition and understanding of the factors driving forest damage are needed for more efficient risk management and planning. In the present study, we statistically modelled forest damage caused by the windstorm Klaus in south-west France. This event occurred on 24 January 2009 and caused severe damage to maritime pine (Pinus pinaster) forest stands. We aimed at isolating the best potential predictors that can help to build better predictive models of forest damage. We applied the random forest (RF) technique to find the best classifiers of the forest damage binary response variable. Five-fold spatial block cross-validation, repeated five times, and forward feature selection (FFS) were applied to the control for model over-fitting. In addition, variable importance (VI) and accumulated local effect (ALE) plots were used as model performance metrics. The best RF model was used for spatial prediction and forest damage probability mapping. The ROC AUC of the best RF model was 0.895 and 0.899 for the training and test set, respectively, while the accuracy of the RF model was 0.820 for the training and 0.837 for the test set. The FFS allowed us to isolate the most important predictors, which were the distance from the windstorm trajectory, soil sand fraction content, the MODIS normalized difference vegetation index (NDVI), and the wind exposure index (WEI). In general, their influence on the forest damage probability was positive for a wide range of the observed values. The area of applicability (AOA) confirmed that the RF model can be used to construct a probability map for almost the entire study area.

… trees with a damaged taproot were vulnerable to heavy wind during the cyclone. Fruit … Tropical Cyclone Sidr’s powerful category 4 winds lashed Bangladesh on November 14 and 15. …

Many natural forests in Southeast Asia are degraded following decades of logging. Restoration of these forests is delayed by ongoing logging and tropical cyclones, but the implications for recovery are largely uncertain. We analysed meteorological, satellite and forest inventory plot data to assess the effect of Typhoon Doksuri, a major tropical cyclone, on the forest landscapes of central Vietnam consisting of natural forests and plantations. We estimated the return period for a cyclone of this intensity to be 40 years. Plantations were almost twice as likely to suffer cyclone damage compared to natural forests. Logged natural forests (9–12 years after cessation of government-licensed logging) were surveyed before and after the storm with 2 years between measurements and remained a small biomass carbon sink (0.1 ± 0.3 Mg C ha−1 yr−1) over this period. The cyclone reduced the carbon sink of recovering natural forests by an average of 0.85 Mg C ha−1 yr−1, less than the carbon loss due to ongoing unlicensed logging. Restoration of forest landscapes in Southeast Asia requires a reduction in unlicensed logging and prevention of further conversion of degraded natural forests to plantations, particularly in landscapes prone to tropical cyclones where natural forests provide a resilient carbon sink. This article is part of the theme issue ‘Understanding forest landscape restoration: reinforcing scientific foundations for the UN Decade on Ecosystem Restoration’.

Tropical cyclones have direct and indirect repercussions in many coastal areas worldwide. In coastal regions, several studies have identified the driving factors of cyclonic hazards and their associated impacts. However, previous studies have focused little on cyclone-induced damage and loss, consequences, and adaptation strategies. As a result, it is critical to explore the global focus areas of cyclone-related studies. This review systematically examined cyclone-induced damage and loss, its consequences, adaptation strategies in coastal regions, and associated research gaps. Results revealed eight main types of cyclone-induced damages and losses. About 46 % of studies focused on vegetation damages, followed by water and sanitation (11 %), crop damages (8 %), income or business losses (8 %), health and injuries (8 %), land use and land cover changes (8 %), infrastructural damages (5 %), and mixed damages and losses (5 %). These damages and losses led to further consequences, including disruption of biocenoses, fish death because defoliated leaves carried carbon into the water, changes in forest structure and composition, loss of timber plantation confidence, hampering the steady supply of safe drinking water, raising drinking water costs, unsanitary circumstances, an increase in infectious diseases, a decrease in protein consumption, and business and supply chain interruptions. Approximately 35 % of the studies addressed one or more of the thirteen adaptation strategies identified in this review. Most of these studies documented the use of natural regeneration and tree planting as responses to vegetation damage and water purification and the distribution of emergency-safe water in response to water and sanitation damage. The findings have led to a proposal for an adaptation framework for cyclone-induced damage and loss. This review recommended investigating cyclone-induced land use and land cover change, damage to vegetation functional traits and patterns, health and injuries, service networks, and infrastructural damages.

BACKGROUND Many mangrove ecosystems are periodically exposed to high velocity winds and surge from tropical cyclones and often recover with time and continue to provide numerous societal benefits in the wake of storm events. SCOPE This review focuses on the drivers and disturbance mechanisms (visible and functional) that tropical cyclones of various intensities have on mangrove ecosystem properties from around the world, as well as the potential ecosystem services role offered by mangroves along storm-ravaged coastlines. When viewed together, studies describe repeatable types of impact and a variety of responses of mangroves that make them ecologically resilient to high velocity winds, and which have served to advance the notion that mangroves are disturbance-adapted ecosystems. CONCLUSIONS Studies have documented massive tree mortality and forest structural shifts as well as high variability of spatial effects associated with proximity and direction of tropical cyclone trajectory that influence biogeochemical processes, recovery of individual trees, and forest regeneration and succession. Mangroves provide coastal protection through surge and wind suppression during tropical cyclones, and yet are able to overcome wind effects and often recover unless some alternate environmental stress is at play (e.g., hydrologic alteration or sedimentation). Structural elements of mangroves are influenced by the legacies imposed by past tropical cyclone injury, which affect their current appearance, and presumably function of mangroves, at any point in time. However, much is yet to be discovered about the importance of tropical cyclones on these fascinating botanical ecosystems including the role of storm-based sediment subsidies, and much more effort will be needed to predict future recovery patterns as frequency and intensity of tropical cyclones potentially change.

… , or the proportion of uprooted basal area explained 84–85% of the variation in hurricane-… soil turnover period from tree uprooting by Puerto Rican hurricanes is between 1600 and …

ABSTRACT During a moderate to severe hurricane more than 5% of trees snap or uproot, depending on the strength and duration of the storm, causing considerable damage to nearby property, housing, and power lines. This study aims to specify the mechanics of trunk damage and possible repair mechanisms. Field data are assembled from trees after hurricane damage to the trunk. Allometric scaling parameters based on trunk diameter (D ^ exp) are determined for the damaged trees’ height, weight, Safety Factor S.F. and critical wind velocity Vcrit. 55% snap via stress fracture of the trunk, 45% by uprooting of the entire tree. Hurricane boundary layer profiles, shear layer forces, Safety Factor (SF), and critical wind velocity Vcrit are determined. Power law exponents (D ^ exp) predict tree height (0.84), weight (2.68), Safety Factor S.F. (0.74), and critical wind velocity Vcrit (0.33) in terms of trunk diameter, with correlation coefficients r = 0.94 to 0.99. Critical velocity Vcrit (wind velocity above which the tree will fail) is found to scale as the Safety Factor S.F.^ (1/2). In conclusion, strategic use of clamps, bolts, tree sap and cables allows restoration of uprooted or snapped trunks for some hurricane damaged trees. Success rate for repair is 67%, average longevity after repair 5.6 years for medium-sized commercially valuable trees.

… (57.3%) than uprooted trees (39.1%) up to 68 weeks after Hurricane Hugo. The differences … snapped trees (16-104 weeks after the hurricane) and the current study, where uprooting …

… Although survival in year 1 was greatest in larger trees, subsequent mortality in large, uprooted trees produced a significant relationship between diameter and mortality (logistic …

… to the hurricane was 9%. Mortality among trees was primarily due to uprooting and broken stems… Many surviving trees sprouted new branches following the hurricane, indicating that this …

… tree, certain cutting practices, and (or) low soil cohesion and shear strength. The root plate of an uprooted tree … and the amount of backward displacement during uprooting. This paper (i) …

Several hurricanes struck Florida, U.S. in 2004 and 2005 causing widespread damage to urban and rural areas. We measured the impacts of five of these hurricanes on the urban forest and combined these results with four other hurricanes to present an assessment of wind resistance for southeastern United States coastal plain tree species. Urban forest loss was positively correlated with wind speed. Tree species demonstrating the highest survival in winds were sand live oak (Quercus geminata), American holly (Ilex opaca), southern magnolia (Magnolia grandiflora), live oak (Quercus virginiana), wax myrtle (Myrica cerifera), sweetgum (Liquidambar styraciflua), crapemyrtle (Lagerstroemia indica), dogwood (Cornus florida), and sabal palm (Sabal palmetto). In a statistical comparison of sand live oak, live oak, and laurel oak (Quercus laurifolia) survival after four panhandle hurricanes, laurel oak had significantly poorer survival than both live oak and sand live oak. Among all species, larger trees lost more branches than medium and smaller trees. Leaf loss had a positive relationship with survival; losing leaves during the hurricane meant higher survival. Trees growing in groups or clusters had greater survival than those growing as individual trees. Tree species with higher wood density had greater survival. Tree species categorized as having dense crowns lost more branches than those with moderate and open crowns; however, contrary to the literature, dense-crowned species survived best. A survey of arborists, scientists, and urban foresters ranked species for their wind resistance. Using our results from hurricane measurements and incorporating results from the survey and the scientific literature, we have developed lists of relative wind resistance for tree species in the southeastern coastal plain. These lists should be used with caution with the knowledge that no species and no tree is completely windproof. In addition, local considerations such as soil, cultural practices, tree age and health, and other urban forest conditions need to be taken into account.

… Tree size was related to hurricane damage. Diameters and heights of trees that uprooted were … Only four percent of all trees left upright after the hurricane died, while most trees that …

… Fiftynine of the 62 mounds and pits on the present research area have been attributed to uproot ings resulting from winds of hurricane origin. The more extensive the observations of …

Abstract Understanding hurricane resistance and resilience in tree species is a challenge to the management and conservation of coastal tropical forests. Tree responses to hurricanes partly depend on species attributes related to architecture and resource use strategy; however, few studies have used multiple traits to identify the role of functional trade-offs in tree resistance and resilience. In this study, we apply a functional traits approach to explore how characteristics involved in tree shape, size and function influence the type and severity of damage by hurricane winds, and examine the potential for recovery by re-sprouting. We tested the hypothesis that traits involved in the fast-slow trade-off mediate tree responses to hurricanes. Eighteen months after the passing of a category 2 hurricane, we assessed the damage types found in 993 trees of dbh > 10 cm, from 36 dominant tree species in a tropical dry forest on the Mexican Pacific coast that was impacted by the event, and measured five functional traits related to species size, architecture and resource acquisition strategy. In addition, the sectional area recovered by re-sprouting in main tree trunks or branches was measured in 16 species. The results indicated that several traits could serve as good indicators of resistance and resilience. Maximum height, wood density and specific leaf area correlated positively with severe damage (together accounting for up to 47% of the variance in uprooting). In turn, re-sprouting recovery was positively associated with maximum height and specific leaf area but negatively with wood density and slenderness (together informing ca. 50% of the variance). We found evidence that the fast-slow continuum of resource use strategies can mediate the capacity of trees to resist and recover following hurricane winds; however, contrary to expectation, the consequences of the fast-slow syndrome for the response to hurricanes seem to vary with the axis of plant strategies considered. Our results challenge the notion that dense-wooded trees of the tropical dry forest should resist hurricanes better, and suggest that these climatic events may actually favor light-wooded, wide-stemmed trees.

In 1998 when Hurricane Georges (177 km/h) crossed over the entire island of Puerto Rico, and in 2004 when Hurricanes Jeanne (193 km/h) and Charley (233 km/h) struck south Florida, U.S., we measured the impacts of these hurricanes on the urban forest composed of tropical and subtropical species. In addition, we also used previous published data for Hurricane Andrew for some analyses. The percent urban forest loss ranged from 13% for Georges to 16% for Jeanne to 18% for Charley. In Hurricanes Jeanne and Charley, palms survived significantly better than all other trees. Some of the best surviving species in Florida’s hurricanes were gumbo limbo (Bursera simarouba), sea grape (Coccoloba uvifera), strangler fig (Ficus aurea), live oak (Quercus virginiana), laurel oak (Quercus laurifolia), and baldcypress (Taxodium distichum). Of the species measured in Puerto Rico, the species with the highest survival and least branch damage were Santa Maria (Calophyllum calaba), Caribbean pine (Pinus caribaea), schefflera (Schefflera actinophylla), and West Indian mahogany (Swietenia mahogani). Losing leaves during these hurricanes had no relationship with how well trees survived. In Hurricanes Jeanne, Charley, and Georges, 3%, 4%, and 11%, respectively, of the trees that fell damaged property. Native tree species survived better than exotic species in Hurricanes Jeanne and Charley but not in Hurricane Georges. Trees growing in groups had greater survival and less branch loss in Hurricane Jeanne than those growing individually. Wood density was not related to survival or branch loss for tree species in Hurricanes Jeanne, Charley, Georges, or Andrew. Two other measurements of wood strength, modulus of elasticity and modulus of rupture, were related to survival and branch loss in Jeanne but not Charley. Tree species with dense crowns had greater survival and less branch loss than moderate- or open-crowned species. Tree species with decurrent growth form survived better than excurrent trees in Hurricane Jeanne with no difference in Charley. Trees with the most rooting space (>7 m2) had the lowest branch loss and the greatest survival in Hurricane Georges. A reanalysis of seven dicot species and their survival in Hurricane Andrew showed that survival for pruned trees was 73% compared with 47% for unpruned trees. A survey of 85 arborists, scientists, and urban foresters ranked species for their wind resistance. Using our results from hurricanes and incorporating results from the survey and the scientific literature, we have developed lists of relative wind resistance for tropical and subtropical tree species. These lists are presented with the caveat that no tree is completely windproof and that other factors such as soil conditions, wind intensity, cultural practices, and tree health and age also contribute to wind firmness.

… after Hurricane Joan to negligible in parts of Jamaican montane forest after Hurricane Gilbert; felling of trees by uprooting and snapping (80% in Nicaragua to 14% in Jamaica); and tree …

… 2 Stems uprooted by the hurricane (if they were ? 40? from their pre-hurricane position and if … the root plate, or if snaps had been caused in surrounding stems by the uprooted stem). …

… Windthrows reduced tree density by 19–39% and basal area (BA) by 30–53% … uprooted (17–38% of all trees) versus broken below 1.8 m height (0–3%). Most species were uprooted in …

Tropical cyclones are expected to intensify under a warming climate, with uncertain effects on tropical forests. One key challenge to predicting how more intense storms will influence these ecosystems is to attribute impacts specifically to storm meteorology rather than differences in forest characteristics. Here we compare tree damage data collected in the same forest in Puerto Rico after Hurricanes Hugo (1989, category 3), Georges (1998, category 3), and María (2017, category 4). María killed twice as many trees as Hugo, and for all but two species, broke 2- to 12-fold more stems than the other two storms. Species with high density wood were resistant to uprooting, hurricane-induced mortality, and were protected from breakage during Hugo but not María. Tree inventories and a wind exposure model allow us to attribute these differences in impacts to storm meteorology. A better understanding of risk factors associated with tree species susceptibility to severe storms is key to predicting the future of forest ecosystems under climate warming. Given the potential for increasingly common and intense tropical storms, it is important to understand their effects on island forest communities. Here, the authors show that Hurricane María’s strength and rainfall had larger effects on tree mortality than other less severe storms, and that large trees and species with low-density wood were most susceptible.

Hurricane Igor was a Category 1 hurricane when it passed the island of Newfoundland, Canada, causing extensive damage. Hurricanes are uncommon at northern latitudes, and boreal species are not adapted to hurricane-force winds. Moreover, much of the storm damage was in the urban area of the City of St. John’s, where there are also numerous non-native trees. This research tested whether there were attributes of trees (e.g., height, diameter at breast height, slenderness, species, age, or distance to nearest tree) that may have influenced whether a tree fell or was left standing. The study authors sampled 70 trees and found that DBH was a significant predictor of tree fall (snapping or uprooting). Conifers were no more or less likely to fall in the storm than deciduous trees, nor were native trees more or less susceptible to wind damage than non-natives. These results suggest that for a boreal, urban ecosystem, there are no target species available that could be planted strategically to minimize risk of tree fall in a major wind event. Thus, to minimize storm damage to human-built infrastructure in regions where hurricanes are rare, the best strategy would be to avoid having large trees located in close proximity to infrastructure.

… , felling of trees by snapping and uprooting, and standing tree mortality … trees under windstorm conditions. A field survey indicated that post-hurricane stem condition (snapped, uprooted, …

… major hurricane in broadleaf and pine stands in Northern Nicaragua. First, we described tree … effects: branch loss, snapping and uprooting. Secondly, to assess the potential influence of …

… wind speed is sufficient to break the tree and we can predict the critical wind speed for stem breakage (… However, for the fluctuating wind conditions in a storm, we have to account for the …

Research Highlights: Simulations of treefall patterns during tornado events have been conducted, enabling the coupled effects of tornado characteristics, tree properties and soil conditions to be assessed for the first time. Background and Objectives: Treefall patterns and forest damage assessed in post-storm surveys are dependent on the interaction between topography, biology and meteorology, which makes identification of characteristic behavior challenging. Much of our knowledge of tree damage during extreme winds is based on synoptic storms. Better characterization of tree damage will provide more knowledge of tornado impacts on forests, as well as their ecological significance. Materials and Methods: a numerical method based on a Rankine vortex model coupled with two mechanistic tree models for critical wind velocity for stem break and windthrow was used to simulate tornadic tree damage. To calibrate the models, a treefall analysis of the Alonsa tornado was used. Parametric study was conducted to assess induced tornadic tree failure patterns for uprooting on saturated and unsaturated soils and stem break with different knot factors. Results: A power law relationship between failure bending moments and diameter at breast height (DBH) for the hardwood species provided the best correlation. Observed failure distributions of stem break and windthrow along the tornado track were fitted to lognormal distributions and the mean of the critical wind speeds for windthrow were found to be higher than that for stem break. Relationships between critical wind speed and tree size were negatively correlated for windthrow and positively correlated for stem break. Higher soil moisture contents and lower knot factors reduced the critical wind speeds. The simulations show varying tree fall patterns displaying forward and backward convergence, different tornado damage widths and asymmetry of the tracks. These variations were controlled by the relative magnitudes of radial and tangential tornado velocities, the ratio between translational speed and maximum rotational wind speed and the mode of failure of the trees. Conclusions: The results show the complexity of predicting tornadic damage in forests, and it is anticipated that this type of simulation will aid risk assessments for insurance companies, emergency managers and forest authorities.

… – in particular Norway spruce – are more vulnerable to winter storms than broadleaved deciduous trees, which have shed their leaves. Stem breakage and uprooting also depend on …

… we use an innovative wind–tree interaction model, which allows for large deflection and tree breakage, to … Firstly, initial damage is caused by the impact of strong downward wind gusts. …

… history affect the likelihood of tree failure. Species, height, diameter … trees had been pruned or nearby trees removed were recorded on trees at campsites in a park affected by the storm…

… The relationship of risk of damage to size of tree was very different between events, rising … , uprooted trees created root pits proportional to the size of the tree, and the pit size–tree size …

… life and infrastructures resulting from tree failure in past wind storms, researches on disruptions … There are two failure modes for a tree under strong winds: stem breakage and uprooting. …

… Moreover, retrospective approaches that employ tree demography and dendrochronology … of these storms. To improve predictions of changes in the climatology of these storms, we …

… wind speeds needed to break or uproot the average tree of a forest stand. Based on these models, we developed a wind damage module for the individual tree … For a given wind speed …

ABSTRACT This paper presents a review of our current understanding of the process of wind damage to trees and forests, with a particular, but not exclusive focus, on planted and managed forests. It makes a direct comparison with the state of knowledge just over 50 years ago when systematic research on wind damage to forests was beginning and discusses how our knowledge has changed over that period. The paper starts with a discussion of the types of severe winds that cause damage and then explores the effect of a number of factors on the risk of wind damage. These include species differences, the influence of different tree characteristics, and the effect of tree competition, tree spacing, gaps and edges in the forest, and soil and site preparation. There is then a section dealing with wind damage at a variety of spatial and temporal scales and the processes occurring at these different scales. The penultimate part of the paper describes the actual physical mechanisms of stem damage and uprooting, how this understanding can be used to develop wind damage risk models, and then how the different parts of the overall wind damage problem can be brought together to form a holistic view. Finally, there is a brief review of the advance in our understanding over the last few decades, the continued areas of uncertainty or that require further work, and recommendations of subjects and topics that could be a focus for future research.

… Tree failures under extreme gusts could exacerbate storm damages to critical infrastructures, … Only tree failure from stem breakage was considered at present (Lu and Zhang 2022a), …

… size and thinning could be applied to future versions of semi-mechanistic models to assess storm damage risk to individual trees in forests with heterogeneous structures. …

… of log defects resulting from storm damage. A significant … of breakage was established, with the smaller diameter trees more … breakage along the stem and the dbh of the trees was found. …

Tree-covered urban green spaces, including streets, parks, and other public areas, are vital for urban sustainability and people’s well-being. However, such trees face threats from the occurrence of extreme weather. In this study, we investigated wind damage to urban trees in the city of Debrecen, Hungary, during two severe windstorms in July 2025. Field surveys were conducted across three distinct urban zones, covering approximately 515,000 m2 in total. We assessed 201 damaged and 325 undamaged trees and recorded the species, size, damage type, and contextual landscape features associated with them being damaged or not. Damage type to trees consisted primarily of broken branches, whilst uprooting and trunk breakage were recorded less often. Most tree characteristics (trunk circumference, height, systematic position, nativity) and the proximity and height of buildings upwind of focal trees were significant predictors of their vulnerability to windstorms. In addition, we surveyed 150 residents in person and received comments from 54 people via online questionnaires and explored their perceptions of storm frequency, the causes of storms, and mitigation measures. Most respondents noted increased storm frequency and attributed that to climate change, and they suggested mitigation measures focused on urban tree management and environmental protection. Some people expressed scepticism about the presence of climate change and/or their ability to address such damage on an individual basis. Our study is the first to integrate assessments of storm-related impacts on urban trees with the opinions of residents living in proximity to them. Our findings highlight the need for climate-adaptive and mechanically robust urban forestry planning and offer insights that guide the management of trees in urban areas globally. Specifically, we propose to undertake the following: (1) Prioritise structurally resilient, stress-tolerant tree species adapted to extreme weather conditions when planting new trees. (2) Integrate wind dynamics, microclimatic effects and artificial stabilisation techniques into urban design processes to optimise tree placement and their long-term stability. Urban planners, builders, developers, and homeowners should be informed about these stabilising practices and incorporate the needs of trees early in the design process, rather than as decorative additions. (3) Develop regionally calibrated risk models and early-warning systems to support proactive and data-driven tree management and public safety. (4) Promote climate literacy and public participation to strengthen collective stewardship and resilience of urban trees.

Widespread degradation of tropical forests is caused by a variety of disturbances that interact in ways that are not well understood. To explore potential synergies between edge effects, fire and windstorm damage as causes of Amazonian forest degradation, we quantified vegetation responses to a 30‐min, high‐intensity windstorm that in 2012, swept through a large‐scale fire experiment that borders an agricultural field. Our pre‐ and postwindstorm measurements include tree mortality rates and modes of death, above‐ground biomass, and airborne LiDAR‐based estimates of tree heights and canopy disturbance (i.e., number and size of gaps). The experimental area in the southeastern Amazonia includes three 50‐ha plots established in 2004 that were unburned (Control), burned annually (B1yr), or burned at 3‐year intervals (B3yr). The windstorm caused greater damage to trees (>10 cm DBH) in the burned plots (B1yr: 13 ± 9% of 785 trees; B3yr: 17 ± 13% of 433) than in the Control plot (8 ± 4% of 2,300; ± CI). It substantially reduced vegetation height by 14% in B1yr, 20% in B3yr and 12% in the Control plots, while it reduced above‐ground biomass by 18% of 77.7 Mg/ha (B1yr), 31% of 56.6 (B3yr), and 15% of 120 (Control). Tree damage was greatest near the agricultural field edge in all three plots, especially among large trees and in B3yr. Trunk snapping (70%) and uprooting (20%) were the most common modes of tree damage and mortality, with the height of trunk failure on the burned plots often corresponding with the height of historical fire scars. Of the windstorm‐damaged trees, 80% (B1yr), 90% (B3yr), and 57% (Control) were dead 4 years later. Trees that had crown damage experienced the least mortality (22%–60%), followed by those that were snapped (55%–94%) and uprooted (88%–94%). Synthesis. We demonstrate the synergistic effects of three kinds of disturbances on a tropical forest. Our results show that the effects of windstorms are exacerbated by prior degradation by fire and fragmentation. We highlight that understorey fires can produce long‐lasting effects on tropical forests not only by directly killing trees but also by increasing tree vulnerability to wind damage due to fire scars and a more open canopy.

In much of the central and eastern United States, tree damage is typically the most common damage indicator available to National Weather Service meteorologists estimating wind speeds from convective storms. Unfortunately, most meteorologists have little or no formal training in the susceptibility of trees to high winds, and the Enhanced Fujita scale does not address many of the various factors that affect the wind tolerance of trees. This study attempts to describe these factors and to provide a strategy for integrating them when estimating wind speeds based on tree damage. Several case studies are used to illustrate the problems and possibilities in deriving a more detailed damage scale than currently exists.

… In this study, we investigate the consistency of damage risk factors among storms as well as … categories: uprooted, breakage, leaning and leaned on. All of the tree data were compiled …

Arborists and urban foresters are increasingly concerned with tree risk management. The aerodynamic drag equation is a potentially useful management tool. Some sources question the form of equationspecifically, the velocity exponentthat should be applied to trees. For the tree risk manager, concerned with public safety and legal liability, this is more than an academic curiosity. Uncertainty about the appropriate exponent questions the reliability of the conventional form. This paper reviews the literature, reports on modeling of both equation forms, and concludes that the conventional formvelocity squaredis appropriate for trees. Detailed analysis is presented for the researcher or advanced practitioner. A summary explanation is provided for the typical practitioner.

Abstract Urban trees can play a crucial role in developing sustainable, safe and resilient cities, but at the same time they can pose risks. The study deals with a procedure able to quantify the risk that a tree subjected to the action of a windstorm, without or with ongoing precipitations (a rainstorm), can cause by falling on potential targets located over its area of influence. The procedure has a modular structure: it is based on the combination of four components (hazard, exposure, vulnerability and damage) that can be developed and/or adapted to different case studies by maintaining the same configuration. Two concepts are introduced and discussed: the “Scale”, concerning the spatial extension over which the analysis is performed, and the “Degree of Knowledge” (DoK), on the accuracy devoted to estimate each component involved in the risk definition. Firstly, each procedure component is described, and the principles behind its division in four DoKs are explained. Then, the risk-analysis procedure is tested by means of a practical example. Results obtained with different DoKs in defining the hazard component are compared and discussed. The procedure is able to quantify the risk, but the lack of literature data seems to affect its reliability. Thus, aiming at the development of a tool as less subjective as possible, some topics where further research is needed are identified.

… and the measured wind speed is not enough to evaluate wind damage to trees and other … Wind Damage to Urban Trees The effects of windstorms on urban trees also depend on the …

The failure of urban street trees caused by strong winds and has several adverse effects on urban functions and public safety. This study developed a wind fragility model based on the mechanical analysis of urban street trees. The uncertainty of the important parameters involved in this model was quantified for species of interest. Specifically, the vine copula function was used to estimate the joint probability distribution of the geometric parameters. Furthermore, the tree fragility curves were obtained and then validated by the historical measured date. The proposed model may help in effectively identifying high-risk streets and regions.

As an important part of the urban environment, trees have certain risks while living in harmony with humans. For example, the failure of trees in extreme weather may cause casualties and damage to public and private; the decline and death of old and valuable trees can have an impact on the diversity and cultural value of trees. This paper outlines the theories related to tree risk and the development of tree risk assessment, evaluates the advantages and disadvantages of various tree risk assessment methods in existing studies, and explains some factors affecting the bearing capacity and related applications using knowledge of tree mechanics. Approaches in modern probing techniques are applied to study the response and loading of tree crowns and branches under wind loads, the application of different non-destructive testing techniques in visual assessment for detecting internal defects and root distribution of trees, and the role and impact of objective quantitative test results on tree risk assessment. Finally, the future development direction of tree risk assessment is predicted, which provides an important reference for research on tree risk assessment.

Focusing on the prediction of urban tree destruction during rainstorms, this study proposes a tree destruction model for wind and rain coupled environments considering the effects of …

… Urban trees play a critical role in regulating urban wind environments and enhancing city resilience, while simultaneously being vulnerable to wind… damage and risk evaluation criteria. …

Typhoons are an extreme weather disaster that strikes coastal cities in south-eastern China every year. This study was based on a tree management project counter measuring to typhoon disasters in a park in Guangzhou, China. Based on the tree risk assessment methods, the research group tempted to explore a much more precise management basing on the wind field characters of the park. Thus, this study conducted some explorations on computational fluid dynamic (CFD) methods on extreme strong wind simulations in the urban environment to find out the field character and support the tree management works in future. Main results were found out in this research: (1) The CFD simulation revealed that the main risk area of the Central Park lied at the southern area, west-northern area, and both paths on the eastern and western sides; (2) The peak wind speed at the height of 5 m and 10 m could reached the wind scale of level 9 to level 11 when the boundary wind speed was set at 24 m/s; (3) With the overlapping of tree locations and wind risk areas, this study could support the tree management in a much more precise way in future. Thus, this study provided a CFD method on urban extreme wind assessment for tree management, which would be valuable for other similar problems in urban environments.

… , it is important to study the wind resistant of urban trees in order to address outdoor natural … and wind tunnel experiment can only model the simplified street canyon with roadside trees, …

… to identify wind angles at which trees offer protection … of trees in risk assessment models. The study offers insights for enhancing urban planning and improving disaster resilience in tree-…

… coarse-grained soil on tree stability were investigated in this study… modeling were performed to study tree stability in an improved soil. … the maximum wind force needed to uproot the tree. …

… in wind loading on trees due to tree spacing and wind speed was examined in the field and in the wind … The wind tunnel measurements were made with dynamically correct 20-cm tall …

… related to tree-pulling and wind tunnel experiments and mechanistic modeling approaches to increase our understanding of the mechanical stability of trees under static loading. Wind, …

… Recent research on the measurement of dynamic wind loads and the effect on tree stability … of how different trees cope with winds. Dynamic loads have been measured on trees with …

… ► Tilt of tree root plates in high winds to assess tree stability. ► … load tests may not represent dynamic wind loading. ► Measuring root plate tilt is a useful method to assess tree stability …

The dynamic forces on tree structures during periods of high winds is being studied in order to determine the loads on trees and the responses of the trees to those dynamic loads. Field measurements of dynamic forces on trees, branches, and cables have been conducted on urban trees in an attempt to quantify the magnitude of these forces and to provide a basis for evaluating tree stability. Equipment was constructed to measure the dynamic wind loads on tree trunks and branches in situ. This equipment is described, and results are presented which indicate that tree structure is loaded by highly variable wind gusts and responds by behaving in a complex dynamic manner, which minimizes the energy transfer from the wind to the tree structure. The dynamic response of the tree involves a complex interaction of the natural frequencies of each component of the tree, including the trunk, main branches, sub-branches, and smaller sections. A dynamic model of trees is presented and includes mass damping that minimizes the sway energies and combines with the drag forces of the canopy to help the tree cope with large wind forces. A discussion of windthrow and tree dismantling is presented, based on the information collected from these studies.

… In this review, we demonstrate the basic biomechanical considerations of tree stability in form of a case study looking at a Norway spruce tree which was uprooted in a storm presumably …

… tree within uniform stands. This paper presents measurements made of wind loading on trees … structure and management history, but all well-acclimated to current wind conditions. Each …

The parameterization of hybrid-mechanistic storm damage models is largely based on the results of tree pulling tests. The tree pulling tests are used for imitating the quasi-static wind load associated with the mean wind speed. The combined effect of dynamic and quasi-static wind loads associated with wind load maxima is considered by either linearly increasing the quasi-static wind load by a gust factor or by using a turning moment coefficient determined from the relationship between maxima of wind-induced tree response and wind speed. To improve the joint use of information on dynamic and quasi-static wind loading, we present a new method that uses the coupled components of momentum flux time series and time series of stem orientation of a plantation-grown Scots pine tree. First, non-oscillatory tree motion components, which respond to wind excitation, are isolated from oscillatory components that are not coupled to the wind. The non-oscillatory components are detected by applying a sequence of time series decomposition methods including bi-orthogonal decomposition and singular spectrum analysis. Then, the wind-excited tree response components are subjected to dynamic time warping, which maximizes the coincidence between the processed data. The strong coincidence of the time-warped data allows for the estimation of the wind-induced tree response as a function of the effective wind load using simple linear regression. The slope of the regression line represents the rate of change in the tree response as the effective wind load changes. Because of the strength of the relationship, we argue that the method described is an improvement for the analysis of storm damage in forests and to individual trees.

Quantifying wind loads acting on forest trees remains a major challenge of wind-tree-interaction research. Under wind loading, trees respond with a complex motion pattern to the external forces that displace them from their rest position. To minimize the transfer of kinetic wind energy, crowns streamline to reduce the area oriented toward the flow. At the same time, the kinetic energy transferred to the trees is dissipated by vibrations of all aerial parts to a different degree. This study proposes a method to estimate the effective wind load acting on plantation-grown Scots pine trees. It evaluates the hypothesis that the effective wind load acting on the sample trees can be estimated using static, non-destructive pulling tests, using measurements of stem tilt under natural wind conditions and static, non-destructive pulling tests. While the analysis of wind-induced stem displacement reconstructs the temporal tree response dynamics to the effective wind load, results from the pulling tests enable the effective wind load quantification. Since wind-induced stem displacement correlates strongly with the sample trees’ diameter at breast height, the effective wind load estimation can be applied to all other trees in the studied stand for which diameter data is available. We think the method is suitable for estimating the effective wind load acting on trees whose wind-induced response is dominated by sway in the fundamental mode.

To persist and survive in any environment, a tree must be mechanically reliable and achieve a reasonable factor of safety. This safety factor, which must be adjusted over the course of plant growth, can be computed for stems and roots based on the quotient of the working load and load-bearing capacity of each organ. This method is illustrated for the stems of cherry trees (Prunus serotina) and for the root systems of an arborescent columnar cactus (Pachycereus pringlei) differing in size. The factor of safety of these organs decreases with increasing plant size. The susceptibility of stems and roots to mechanical failure thus increases as plants grow in mass or height. However, the risk of wind-induced tree failure is reduced in the case of cherry trees by the selective wind-failure of small peripheral branches, which reduces the overall drag forces and bending moments acting on trunks. In the case of the columnar cactus, the demand for root water absorption/storage may take precedence over anchorage as plants increase in overall size. These two case studies illustrate that manifold factors of safety must be considered and ranked simultaneously in terms of the probability of damage or death for different environmental risk factors.

… There have been considerable advances in our understanding of the interactions between wind and trees, particularly the mechanical stability of trees subjected to strong winds, over …

… 7.20 shows how the stress distribution changes with the loading point. A tree pulled from too … the Gardiner Average Tree probably has a growth-experience of wind loading with a centre …

… The loads imposed by the wind on a tree's anchorage are not static, however. Wind speed varies rapidly with time, so that the forces acting on a tree change and the tree itself sways. A …

… We report on a wind-tunnel study with 1 : 75 scale model trees designed to examine the influence of canopy structure on the formation of turbulent gusts above forests. This was to test …

… a basis for evaluating tree stability. The results … wind loads exerted on model and real prototype trees tested for a typical vegetated building envelope. Wind loads on model-scale trees …

… ability of trees to develop stronger anchorage with specific root traits as a biomechanical response to the wind. We therefore have to provide a tool capable of predicting tree stability by …

… To this purpose, this study investigates tree vulnerability to wind load downwind from leading edges designed with various treatments: sharp, tapered, sparse, dense, tall and small …

… in field tests on trees that were statically loaded, then on trees subject to natural wind conditions. The … Under natural wind conditions the maximum root plate tilt recorded was 0.88. Some …

Abstract Typhoons of varying intensities severely impact ecosystem functioning in tropical regions and their increasing frequencies and intensities due to global warming pose new challenges for effective forest restoration. This study examines the impact of a super-typhoon (Mangkhut) on the regenerating native secondary forest and exotic monocultural plantations in the degraded tropical landscape of Hong Kong. The super typhoon, which hit Hong Kong on 16 September 2018 lasted for 10 h (09:40–19:40) and was the most severe storm affecting Hong Kong over the past 100 years. Hong Kong's secondary forest is a mosaic of forest patches recovering through natural succession since 1945, and plantation stands of exotic monocultural species. We determine the loss in biomass by performing NDVI (Normalized Difference Vegetation Index) difference analysis using two Landsat-8 multispectral images acquired before and after the typhoon. This the assessment of typhoon impacts according to successional age group, structural stages of vegetation, landscape topography, and on stands of exotic plantations. Results indicate that hilltops, open shrubland and grassland were hard hit, especially on southwest and southeast facing slopes, and almost 90% of the landscape showed abnormal change. Patches of exotic monoculture plantation (Lophostemon confertus, Melaleuca quinquenervia, and Acacia confusa) were the most severely damaged by the typhoon, showing more than 25% decrease in NDVI, followed by young secondary forest. Field observations confirmed that in exotic plantations, almost the entire canopy was destroyed and there is no generation of young under story trees to replace those lost. The affected young forests and shrublands are mainly dominated by fast growing, soft wooded early successional species such as Mallotus paniculatus or Machilus chekiangensis as well as weak, multi-trunked, fungus infected, or other structurally deficient trees, which were uprooted or seriously damaged by typhoon gusts. The net effect of typhoons in Hong Kong's degraded landscape, appears to reinforce the arrested succession of dense, less diverse stands of weaker early successional species due to the absence of late and middle successional species and native dispersal agents. In order to obtain a stronger, more resilient forest, it would be necessary to enhance biodiversity by artificially planting a species mix, which resembles primary forests in the region. This could be achieved by thinning of young secondary forest followed by enhancement planting of pockets of high diversity forest.

Abstract The extent and state of ecosystem health of Philippine mangroves are affected by the occurrences of typhoons (ca. 20 per year). While severe damages (and sometimes even total forest collapse) are commonly reported, there are some cases where mangroves are less damaged and easily recovered implying that some mangroves are either highly vulnerable or resilient. Most studies on effects of typhoons in mangroves (including post-typhoon recovery) are mainly focused on vegetation but rarely on changes in sediment and faunal composition and activities. Also, these studies are mostly short-term and rapid (

… of mangrove forests, vegetation in permanent plots was surveyed at 1, 12, and 24 months after … diameter and tree height, and a negative correlation with the tree density. S. apetala, A. …

… happened within the first year post-typhoon. By the 2010 … the extra light reaching the post-typhoon forest continued for … We suggest that medium-sized trees survived best because …

The frequency and intensity of typhoons have increased due to climate change. These climate change-induced disasters have caused widespread damage to forests. Evaluation of the …

In December 2021, a severe typhoon caused widespread damage to forest ecosystems across Northern Mindanao, including the Dinagat Islands, an ecologically significant area yet subjected to ongoing mining activities. This study presents a post-disturbance floristic and biomass assessment conducted two years later within a 226-hectare Mineral Production Sharing Agreement site in Cagdianao, Dinagat Islands, Philippines. The objective was to evaluate early forest regeneration, species diversity, and biomass dynamics in a disturbed tropical mining landscape. Vegetation was dominated by young regrowth, primarily sapling-stage trees. Using a quadrat-transect design with 10 × 10 m plots spaced at least 250 m apart, the survey documented 48 tree species from 42 genera and 28 families, with an overall Shannon–Wiener diversity index (H’) of 3.142, ranging from 0.974 to 2.424 across sampling stations. The understory vegetation comprised 69 taxa representing 40 families, indicating a heterogeneous plant community in early succession. Conservation assessments identified nine species listed on the IUCN Red List and seven categorized as threatened under DENR DAO 2017-11. Remote sensing analysis using ESA Biomass data revealed that 51.4% of the area experienced biomass loss immediately after the typhoon, resulting in a net decline of 4.28%, but partial recovery of 25.63% was observed in 2022. These findings underscore the importance of integrating floristic assessments with satellite-derived biomass monitoring to track post-disturbance ecosystem dynamics. The study contributes to evidence-based biodiversity conservation, ecological monitoring, and the development of sustainable post-mining rehabilitation strategies in typhoon-prone tropical ecosystems.

With drastic changes to the environment arising from global warming, there has been an increase in both the frequency and intensity of typhoons in recent years. Super typhoons have caused large-scale damage to the natural ecological environment in coastal cities. The accurate assessment and monitoring of urban vegetation damage after typhoons is important, as they contribute to post-disaster recovery and resilience efforts. Hence, this study examined the application of the easy-to-use and cost-effective Unmanned Aerial Vehicle (UAV) oblique photography technology and proposed an improved detection and diagnostic measure for the assessment of street-level damage to urban vegetation caused by the super typhoon Mangkhut in Shenzhen, China. The results showed that: (1) roadside trees and artificially landscaped forests were severely damaged; however, the naturally occurring urban forest was less affected by the typhoon. (2) The vegetation height of roadside trees decreased by 20–30 m in most areas, and that of artificially landscaped forests decreased by 5–15 m; however, vegetation height in natural forest areas did not change significantly. (3) The real damage to vegetation caused by the typhoon is better reflected by measuring the change in vegetation height. Our study validates the use of UAV remote sensing to accurately measure and assess the damage caused by typhoons to roadside trees and urban forests. These findings will help city planners to design more robust urban landscapes that have greater disaster coping capabilities.

… Post-typhoon DBH distribution of the major tree species in a 3.3-ha plot. standing live trunks … In this study plot, different post-typhoon regeneration patterns will refill the different sized …

Urban vegetation plays a vital role in developing sustainable cities via essential urban ecoservices. Potential threats, however, from natural disturbances to urban vegetation and its resilience remain unclear at local scales. Taking the super typhoon Mangkhut in 2018 as an example, this study aimed to develop a resilience index to evaluate the impacts of super typhoons on urban vegetation in Hong Kong at the species level. The typhoon impacts and canopy recovery of four tree species were assessed by integrating field and remote sensing data. First, we discussed the specific influencing factors of the typhoon. Second, we constructed a normalized seasonal difference vegetation index (NSDVI) to identify and characterize the distribution of tree species. Then, a seasonal resilience index was developed at the species level to investigate the severity and recovery of the vegetation after the typhoon. The results demonstrated that strong wind was the leading cause of damage. NSDVI improved tree species identification by more than 10 percent compared with conventional methods. In terms of the resilience analysis, 87.25 percent of the trees were affected by the typhoon. Royal palm (Roystonea regia) performed well among the four species during the typhoon, suffering minor losses. A total of 47.95 percent of the trees recovered to their pretyphoon state two years after the typhoon. The recovery speed of Hainan ormosia (Ormosia pinnata) was the fastest. This research provides a scientific reference for the planning of urban vegetation species to increase their resilience and ability to provide ecoservices despite natural disturbances.

Forests provide valuable resources for households in the Philippines, particularly in poor and upland communities. This makes forests an integral part of building resilient communities. This relationship became complex during extreme events such as typhoon occurrence as forests can be a contributor to the intensity and impact of disasters. However, little attention has been paid to forest cover losses due to typhoons during disaster assessments. In this study, forest damage caused by typhoons was measured using harmonic analysis of time series (HANTS) with Landsat-8 Operation Land Imager (OLI) images. The ΔHarmonic Vegetation Index was computed by calculating the difference between HANTS and the actual observed vegetation index value. This was used to identify damaged areas in the forest regions and create a damage map. To validate the reliability of the results, the resulting maps produced using ΔHarmonic VI were compared with the damage mapped from PlanetScope’s high-resolution pre- and post-typhoon images. The method achieved an overall accuracy of 69.20%. The accuracy of the results was comparable to the traditional remote sensing techniques used in forest damage assessment, such as ΔVI and land cover change detection. To further the understanding of the relationship between forest and typhoon occurrence, the presence of time lag in the observations was investigated. Additionally, different contributing factors in forest damage were identified. Most of the forest damage observed was in forest areas with slopes facing the typhoon direction and in vulnerable areas such as near the coast and hill tops. This study will help the government and forest management sectors preserve forests, which will ultimately result in the development of a more resilient community, by making it easier to identify forest areas that are vulnerable to typhoon damage.

… Our results demonstrate the value of harmonized multi-temporal LiDAR for landscape-scale monitoring of biomass recovery and highlight delayed but substantial post-typhoon carbon …

… Mangrove areas were mapped prior to Haiyan using 30 m Landsat imagery and a supervised decision-tree classification. A time sequence of 250 m eMODIS data was used to monitor …

This study compared the effects of super typhoons and earthquakes on forest succession at the slopes of the Rokko Mountains in Japan. According to changes in the enhanced vegetation index (EVI), the super typhoon in 1991 caused severe, widespread damage to topographically distinct forest stands across the mountains. A major earthquake in 1995 with a magnitude of Mj = 7.2 caused moderate effects on the EVI. The 1994 super typhoon and the 1995 major earthquake exhibited similar spatial damage patterns, with impacts concentrated on the northern slopes. Although the 2018 super typhoon recorded higher wind speeds, there was no reduction in forest stands across the mountains, indicating an increase in forest resilience. Nevertheless, detailed observations revealed localized, patchy impacts in 2018, specifically the death of some evergreen trees on the northern slopes. The 1991 typhoon diminished up to 14% (conf. int. 95%: ±3%) of the pre-typhoon EVI values for the most negatively affected forest stands. Hence, the typhoons were thought to be the primary driving force that accelerated the forest succession by eliminating vulnerable trees. This elimination enhanced the increasing dominance of broadleaved evergreen laurel tree species, which are known to have stronger root systems than the vulnerable conifers. In addition, it was revealed for the first time that multiple vegetation types on slopes under the same topographical conditions were commonly damaged by multiple super typhoons within a 27-year period, during which typhoon-enhanced forest succession was strongly pronounced. The findings offer beneficial prospects for proactive climate-resilient forest management and disaster mitigation strategies tailored to slope-specific vulnerabilities. This study is the first to compare the effects of super typhoons and a major earthquake on forest stands.

… mechanical stress conditions for an environment. However, to clarify the stress as applied to a tree in this chapter, wind … tissues which resist the effect of the wind, and return the tree to its …

Many of the features of trees represent arrangements that minimize the chance that they will uproot when exposed to high winds. At least four schemes, singly or in combination, keep the bases of trees from rotating in the face of the turning moment imposed by the drag of their leaves. Trunks and petioles are relatively more resistant to bending than to twisting, giving good support but permitting drag-reducing reconfiguration in high winds. Leaves curl and cluster in a variety of ways, all of which greatly reduce the drag they incur relative to the values for ordinary thin and flexible objects such as flags. However, information derived from measurement and experimentation about such mechanical matters is still quite limited.

Survival in variable conditions of wind exposure depends on the strategy of trees in adapting to environmental constraints. There are many studies investigating the effect of wind on the adaptation of trees, but little attention is paid to the properties of the wood, particularly within-stem variability. In the present work, an analysis was made of within-stem variability of the density and mechanical properties of Scots pine wood from parts of stands with different wind exposure (stand edge, forest interior). The research was carried out in north-western Poland, in seven selected pine stands (without other species in the canopy) aged from 82 to 87 years. In each stand, three trial plots were marked, each at a different distance from the edge of the stand. The first plot was immediately adjacent to the edge (0–20 m), the second was at a distance of 30–50 m, and the third was at a distance of 60–80 m. Generally, wind exposure, defined by the distance from the windward edge, did not significantly affect the tree morphology and wood properties. A statistically significant difference was found only for the modulus of elasticity (MOE), between stand edge and forest interior. Trees growing at a distance from the stand edge compensate for their greater stem slenderness with higher elasticity. A certain growth response to wind loads is also represented by the within-stem variability of wood. We found that within-stem variability of wood at the stand edge is higher than in the forest interior. At various points along the stem, the wood density and strength were generally higher on the eastern radius (on the leeward side of the stem). Different wind resistance requirements at the stand edge and in the interior lead to combinations of tree architecture and wood properties that enable the best resistance to wind loads.

In urban areas, typhoons frequently cause the tilting and uprooting of trees, resulting in damage to city infrastructure. During periods of intense rainfall, at shallow soil depths, soil water content is typically high, reducing the anchoring resistance of tree roots in the soil. Tree root systems play an important role in providing anchoring resistance against severe winds during typhoons. In this study, we examined the influence of high soil saturation on the turning resistance of trees by conducting winching tests on three tree species found in urban areas. In highly saturated soils, the maximum resisting moment of camphor trees (Cinnamomum camphora (L.) J. Presl.) is 35–50% lower than in soils with low saturation levels. A tree’s maximum resisting moment (TMmax) exhibits a linearly positive relationship with its diameter at breast height (DBH) in near-saturated soil conditions. The ratio of TMmax values to DBH in near-saturated soils is noticeably lower than in low-moisture soils. Our research establishes a relationship between the DBH of trees and the strength of the wind that they can resist during typhoons, as measured on the Beaufort scale.

… wind loading from the predicted wind profile within or in front of the forest and the canopy frontal area, whereas in GALES, the wind loading on trees … continuum of mechanical behaviour. …

… end uses to trees based on their exposure to wind conditions, ensuring optimal utilization. … of current knowledge on tree responses to mechanical loading by wind, with particular …

… Studies of the mechanical stability of trees have historically focused primarily on height–diameter relationships as key functional traits, based on assumptions derived from dynamic …

… larger trees to let the wind penetrate, thereby reducing wind-… to and response to wind as well as from mechanical constraints. … This feature of leaves may reduce wind resistance (drag) of …

… approach to quantify how tree mechanical response to wind varies as the geometrical and … Notwithstanding, other strategies exist in nature to reduce the crown resistance to the flow. …

Aims China is one of the countries in the world most seriously affected by typhoons, which pose a great threat to the eucalyptus plantation industry. However, few studies have comprehensively accounted for the impact of key traits on the wind damage/resistance of eucalyptus. Methods To identify the key factors affecting the wind resistance of eucalyptus, 20 eucalyptus genotypes were selected; a total of 18 traits, including the wind damage index, growth traits, and wood traits, were measured, and the wind resistance was determined via the tree-pulling test. Results Correlation, principal component, canonical correlation, and path analyses were performed to evaluate these traits. Correlation analysis revealed that the wind resistance of eucalyptus plants was related to the tree height, volume, and duration of stress wave propagation. Principal components and tree-pulling variables were further used for correlation and path analyses. Canonical correlation analysis and the PA-OV model showed that holocellulose and lignin contents and fiber width, as well as growth traits, were important factors affecting the stability of standing trees under typhoon conditions. The key traits influencing the wind resistance of Eucalyptus camaldulensis, which may provide a reference for evaluating the wind resistance of Eucalyptus varieties for forest management, were identified. Conclusion This study provides a knowledge base for forest management and planning in typhoon-prone coastal areas, and provides a theoretical basis for the breeding and genetically improving eucalyptus stocks based on wind resistance characteristics.

Abstract This review of tree biomechanics covers recent research publications that offer new insights into how trees respond to mechanical loads and resist failure, especially in winds. Biomechanical studies using dynamic rather than static structural methods are showing that the form of the tree influences dynamic response in winds and differences in tree morphology can produce extreme behaviours such as very little or nearly critical dissipation of stem oscillations. Biomechanical studies on trees that measure the forces, stresses and strains are reviewed including a new method of optical strain measurement where small dots (speckle) sprayed on tree surfaces show the strain distribution of trunks and branches under load. The role of stress and strain in tree growth is currently an important research question and the review includes papers that are indicating that strain may be the factor, more than stress, in triggering adaptive growth response. The importance of the form of trees influencing their wind loading is leading to investigations of the importance of branches, especially in winds where they act like coupled oscillators attached to an oscillating trunk to modify sway behaviour. Branch unions are being studied and new concepts on their attachment are also reviewed. Collectively, these developments are leading to a better understanding of tree biomechanics and the complex dynamic response of trees in wind.

… Susceptibility of trees to wind was computed in terms of tree … Analyses of the mechanical design of trees should also be … aid in explaining trends in wind resistance with tree size. …