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Windthrow

Windthrow, also known as blowdown, is the uprooting, bole snapping, or top breakage of trees caused by strong winds, often acting as a key natural disturbance regime in boreal and temperate forest ecosystems.^[1]^[2] This event typically involves the failure of the tree at the soil-root interface due to wind forces exceeding the anchorage provided by the root system, resulting in trees toppling with their root plates exposed.^[3] Windthrow can affect individual trees or vast areas, creating canopy gaps that range from small openings of tens of square meters to expansive blowdowns covering thousands of hectares, depending on storm intensity and local conditions.^[1]^[2] The primary cause of windthrow is high wind speeds, sustained generally exceeding 90 km/h (Beaufort force 10 or higher) during intense storms such as hurricanes, derechos, or extratropical cyclones, which generate mechanical forces that trees cannot withstand.^[2] These events are exacerbated by predisposing factors, including shallow or poorly drained soils that limit root depth and anchorage, as high water tables reduce soil strength and promote shallow rooting patterns.^[3]^[4] Tree-specific vulnerabilities, such as decay in the root collar or excessive height relative to root spread, further increase susceptibility, with dead or weakened trees being most at risk.^[1] Stand-level conditions like dense spacing, recent thinning, or even-aged monocultures amplify the risk by creating uniform vulnerabilities across the forest, while topographic exposure on ridges or coastal areas heightens wind impacts.^[4] Climate change is projected to intensify windthrow through more frequent and severe storms, increased winter rainfall leading to soil saturation, and faster tree growth that outpaces root development in suitable conditions.^[4] Ecologically, windthrow plays a vital role in forest dynamics by promoting biodiversity through the creation of heterogeneous habitats, including coarse woody debris that supports fungi, insects, and wildlife, and by facilitating nutrient cycling and species succession in the resulting gaps.^[2] However, it also poses challenges, such as opening pathways for invasive pests like bark beetles, which can trigger secondary outbreaks leading to further mortality, and altering carbon storage as disturbed forests may temporarily shift from net sinks to sources.^[1]^[2] Economically, windthrow causes substantial losses in forestry, with annual damages in North America exceeding $2 billion (as of the 2010s) from associated pest epidemics and reduced timber quality, while increasing harvesting costs and safety risks in affected stands.^[2] Management strategies focus on mitigation through site preparation like mole drainage to improve soil stability, species selection for wind-firmness, and diversified planting to reduce uniform risk.^[3]^[4]

Definition and Characteristics

Definition

Windthrow specifically refers to the uprooting of trees due to the mechanical forces exerted by strong winds, representing a form of structural failure at the soil-root interface in forested ecosystems. This distinguishes windthrow from windsnap (bole snapping) or other wind damage such as defoliation or minor branch breakage, though the term is sometimes used more broadly for major wind-induced failures. Events can occur as isolated incidents affecting single trees or as widespread disturbances impacting entire stands, with affected trees often aligned parallel to the prevailing wind direction.^[5]^[6]^[7] The scale of windthrow varies considerably, ranging from individual trees in localized gaps to extensive blowdowns covering hundreds of hectares, depending on factors like storm intensity and forest structure. As a recurrent natural disturbance, windthrow shapes forest dynamics across biomes, with larger events more frequent in regions prone to extreme weather.^[8]^[9] The related term "windfall" dates to the 15th century in early English usage, originally describing trees or fruit felled by wind, while "windthrow" emerged in early 20th-century forestry literature, particularly in European texts from the 19th century onward as a standard descriptor for storm-induced tree uprooting, reflecting observations of widespread forest losses during that period.^[10]^[11]^[12] Quantification of windthrow typically involves assessing the spatial extent through affected area in hectares, timber volume loss in cubic meters, number of impacted trees, or percentage of stand mortality. These metrics, often derived from field surveys or remote sensing, provide essential data for evaluating disturbance severity and informing forest management.^[13]^[14]^[15]

Types and Patterns

Windthrow events manifest in distinct types based on the mode of tree failure, which determines the physical form of damage observed in affected forests. The primary modes include uprooting, where the entire root plate is lifted from the soil, exposing a characteristic mound and pit; stem breakage (windsnap), in which the trunk snaps at varying heights, often due to bending forces exceeding wood strength; and crown stripping, involving the loss of branches, foliage, or entire upper canopies without trunk failure. Uprooting is the most common mode in saturated soils, accounting for a significant portion of damage in temperate and boreal forests, while stem breakage predominates in denser stands where leverage from height amplifies stress. Crown stripping typically occurs in exposed or isolated trees, reducing aerodynamic drag but leaving the stem intact. These modes are not mutually exclusive and can occur simultaneously within a single event, influencing post-disturbance regeneration patterns. Spatial patterns of windthrow vary widely, reflecting interactions between wind direction, topography, and forest structure, and range from scattered to extensive configurations. Mosaic patterns feature isolated gaps or clusters of fallen trees interspersed with intact forest, often forming irregular patches that enhance structural heterogeneity at the stand level. Linear strips commonly align with forest edges, ridges, or wind corridors, where abrupt exposure increases vulnerability, as seen in cutblock boundaries where damage extends 10–50 meters inward. Large-scale blowdowns, covering areas exceeding 100 hectares, produce uniform clearings resembling harvested zones, such as the Great Storm of 1987, which devastated around 16,500 hectares in the UK and additional areas in France. These patterns arise from edge effects, where wind penetration is amplified at boundaries, leading to progressive failure from perimeter trees inward.^[16] Windthrow operates across scales from micro- to landscape-level, with patterns emerging from localized vulnerabilities to regional storm dynamics. At the micro-scale, individual trees or small groups (<1 hectare) succumb in sheltered interiors, often due to inherent weaknesses, creating pinpoint gaps that minimally disrupt canopy continuity. Landscape-scale events, conversely, encompass thousands of hectares, as in Amazonian blowdowns from convective storms, where fan-shaped clearings follow wind trajectories and alter regional carbon dynamics. Edge effects exemplify scale-dependent pattern formation, with wind speed doubling at forest margins and triggering sequential failures that propagate inward, particularly in fragmented landscapes. Temporally, windthrow can be acute, resulting from a single intense storm that causes immediate, widespread failure, or chronic, involving repeated exposure to lower-intensity winds that cumulatively weaken trees over seasons or years. Acute events, like hurricanes, dominate in tropical and coastal regions, felling vast areas in hours and initiating rapid successional shifts. Chronic patterns prevail in windy but storm-poor environments, such as coastal boreal forests, where ongoing gusts erode stability through iterative minor damage, fostering a steady-state mosaic of disturbance rather than abrupt clearings.

Causes and Mechanisms

Meteorological Factors

Windthrow is primarily initiated by extreme wind forces that exceed the structural stability of trees, with critical thresholds typically involving gust speeds surpassing 150 km/h for mature trees in exposed conditions. These gusts create overturning moments through drag forces acting on the tree canopy, which, when leveraged over the stem height, generate torque that can uproot or snap the tree if it overcomes anchorage or bending strength. Turbulence and wind shear amplify this effect; turbulent eddies in the atmospheric boundary layer increase dynamic loading on crowns, while vertical shear enhances gust persistence, prolonging exposure to high winds. Gust factors, often 1.9 times the mean hourly wind speed, further elevate peak loads during storm passages.^[17] The primary storm types driving windthrow are extratropical cyclones, hurricanes, derechos, and downbursts, each generating distinct wind profiles that produce overturning moments. Extratropical cyclones, common in mid-latitudes, deliver sustained high winds over large areas through cyclonic circulation, with gusts amplified by frontal boundaries creating shear layers that apply asymmetric forces on forest canopies. Hurricanes and tropical cyclones impose rotational winds with radial inflow, leading to intense, localized gusts that twist and uplift trees, particularly in coastal zones where forward storm motion adds translational speed. Derechos, associated with mesoscale convective systems, propagate straight-line winds via evaporatively cooled downdrafts, producing horizontal roll vortices that exert uniform but severe shear across swaths of forest, often exceeding 45 m/s. Downbursts, smaller-scale features within these systems, release concentrated downdrafts that diverge at the surface, creating divergent wind fields that maximize torque on individual trees.^[2]^[9]^[17] Synoptic conditions interact with local topography to intensify windthrow risk, as orographic enhancement accelerates airflow over elevated terrain, funneling and compressing winds to produce locally higher gusts. For instance, when storm systems approach ridges or hillslopes, air acceleration upwind can substantially increase local wind speeds compared to flat areas, heightening overturning moments in upland forests. Climate patterns like El Niño-Southern Oscillation (ENSO) modulate storm frequency; during El Niño phases, weakened easterly trades in the tropics reduce convective activity in regions like the Amazon, potentially lowering windthrow incidence, whereas La Niña strengthens these trades, fostering more frequent mesoscale convective storms and associated downdrafts. In extratropical zones, El Niño can shift storm tracks southward, increasing gale frequency in southern Europe and North America.^[17]^[18]^[19] Historical data from major events underscore these dynamics, with European gales often recording gusts over 200 km/h; for example, Storm Lothar in 1999 produced gusts up to 216 km/h across France, Switzerland, and Germany, resulting in widespread windthrow from extratropical cyclone forces enhanced by topographic channeling in the Jura Mountains. Similarly, derechos in North American forests have generated gusts of 42-46 m/s, sufficient to threshold stability in mature stands, as observed in southern Indiana events where slight gust increases (e.g., 0.8 m/s) amplified damage by 38%. In the Amazon, convective storms during La Niña years like 1999 correlated with elevated windthrow densities, driven by high convective available potential energy (CAPE) exceeding 1000 J/kg.^[20]^[17]^[18]

Biological and Site Factors

Biological factors significantly influence tree susceptibility to windthrow, primarily through structural attributes that affect mechanical stability. The height-to-diameter ratio (H/D) at breast height serves as a key indicator of tree slenderness, with ratios exceeding 80 indicating heightened vulnerability to uprooting or snapping under wind loads, as slender trees experience greater leverage from gusts.^[6] Root architecture further modulates this risk; shallow-rooted species, such as many conifers, are more prone to anchorage failure compared to deep-rooted hardwoods, where extensive lateral roots provide superior resistance to overturning moments.^[21] Species-specific vulnerabilities also play a role, with Norway spruce (Picea abies) exhibiting particularly high susceptibility—up to 6.8 times greater than oaks (Quercus spp.)—due to its brittle wood and shallow rooting habits, whereas oaks demonstrate greater resilience through robust stem form and root systems.^[22] Site conditions amplify these biological traits by altering soil-tree interactions and wind exposure patterns. Saturated or poorly drained soils, such as those with high water tables or clay textures, reduce root-soil cohesion, increasing the likelihood of uprooting during storms by promoting soil saturation and plate failure.^[4] Shallow or rocky soils similarly constrain root depth, limiting anchorage and elevating windthrow risk, particularly on exposed sites. Slope angles contribute by influencing wind acceleration and soil stability; steeper slopes (e.g., >30°) can channel winds and erode root support, while leeward positions offer partial shelter. Stand density affects microclimate and load distribution, with dense canopies reducing individual tree exposure through mutual sheltering, but overly sparse stands increasing vulnerability by allowing unimpeded wind penetration.^[23] Forest management practices can either mitigate or exacerbate these predispositions. Uniform age-class stands, often resulting from even-aged silviculture, heighten risk by synchronizing tree dimensions and reducing structural diversity, making entire cohorts more uniformly susceptible as they reach critical heights. Previous disturbances like logging create abrupt edges that expose previously sheltered trees to full wind profiles, substantially elevating windthrow rates in adjacent stands—up to several times higher along clearcut boundaries. Disease-weakened trees, affected by root or stem decay from pathogens such as Armillaria spp., further compromise stability by reducing wood strength and root integrity, rendering them prone to failure at lower wind speeds.^[6]^[24] Quantitative models of critical wind speeds incorporate these factors to predict thresholds for damage, emphasizing tree slenderness as a primary determinant; for instance, mechanistic approaches like those in ForestGALES simulate the wind velocity required for failure based on H/D ratios, rooting depth, and site exposure, highlighting how H/D values above 80 can lower critical speeds by 20-30% in vulnerable species.^[25]

Ecological Impacts

Immediate Effects on Forests

Windthrow events cause abrupt physical alterations to forest structure, primarily through the uprooting or snapping of trees, which creates large canopy gaps that can range from small patches to expansive clearings spanning several hectares. These gaps result from the mechanical failure of trees under high wind forces, leading to the immediate exposure of the forest floor to direct sunlight and altered wind patterns. Additionally, fallen trees generate substantial accumulations of coarse woody debris, including trunks, branches, and snapped limbs. Uprooted trees also produce distinctive soil disturbances in the form of root plates—elevated mounds of soil and roots—and corresponding pits, which disrupt the soil profile, mix organic and mineral layers, and expose subsurface materials, often resulting in 34% lower soil carbon content and 11% higher soil pH in severely impacted sites within the first year.^[26]^[27] At the stand level, windthrow leads to a rapid reduction in basal area, as mature trees comprising the bulk of the stand's biomass are toppled or broken. This structural change sharply increases light penetration into the understory in gap centers compared to intact canopy areas. Initial microclimate modifications follow, including warmer temperatures and fluctuating humidity levels in the gaps due to reduced shading and increased airflow, which can stress surviving vegetation and alter evaporation rates in the short term.^[26]^[2] Wildlife experiences immediate disruptions from these changes, with arboreal species such as canopy-dependent birds and insects facing temporary habitat loss as interconnected tree crowns are fragmented, potentially reducing nesting sites and foraging opportunities in affected zones. Conversely, ground-foraging animals, including certain mammals and invertebrates like carabid beetles, gain enhanced access to previously shaded areas, where the new pit-and-mound topography and debris piles create diverse microhabitats that boost species richness for open-habitat foragers within months. Insect communities shift quickly, with saproxylic species exploiting fresh deadwood, though bark beetle outbreaks can emerge, increasing mortality in bordering trees.^[28]^[2] The scale of these effects varies by storm intensity, but moderate blowdowns—such as those from gusts of 150-200 km/h—typically result in 10-50% stand mortality, as observed in southern boreal forests where species like black spruce and paper birch suffered 12-82% losses across dominant trees in a single event.^[29]^[26]

Long-term Biodiversity Changes

Following windthrow disturbances, ecological succession begins in the created gaps, where pioneer species such as light-demanding herbs, shrubs, and advance regeneration rapidly colonize due to elevated light levels and reduced competition from the former canopy.^[30] Over subsequent decades, these areas transition from dominance by early seral, light-demanding flora to more shade-tolerant species as lateral canopy ingrowth and vertical growth lead to partial closure, fostering a phased recovery toward pre-disturbance conditions.^[31] This dynamic process is evident in temperate and boreal forests, where species like rowan (Sorbus aucuparia) and Norway spruce (Picea abies) often dominate initial regeneration.^[32] These succession patterns generally enhance biodiversity by promoting structural heterogeneity across the forest landscape, with windthrow gaps forming a mosaic that supports varied microhabitats and edge effects beneficial to understory diversity.^[33] Edge habitats emerging from such disturbances foster increased colonization by understory plants and invertebrates, while the accumulation of decaying wood from uprooted trees bolsters nutrient cycling through gradual decomposition, releasing nitrogen, phosphorus, and other elements while serving as substrate for fungi and detritivores.^[34] In central European beech forests, for instance, this leads to elevated herb and beetle richness during mid-succession phases.^[35] However, prolonged or frequent windthrow can introduce negative outcomes, such as the establishment of invasive species in open gaps, where increased light and soil exposure initially favor exotics like certain understory invasives before native competitors recover.^[36] If disturbances recur before full succession, they may promote habitat homogenization by favoring resilient pioneer or grass-dominated communities over diverse late-seral assemblages, potentially delaying recovery to complex forest structures.^[37] Research indicates that windthrow-affected areas often exhibit 17-33% higher species richness in plants and arthropods compared to undisturbed stands after 10-20 years, with diversity peaking early post-event and remaining elevated for two decades before stabilizing.^[38]^[39] In one long-term study of arthropod communities, species numbers remained elevated two decades after disturbance, underscoring the lasting biodiversity boost from such events in mountain spruce forests.^[40]

Human and Economic Dimensions

Forestry and Timber Losses

Windthrow imposes substantial economic burdens on the forestry sector worldwide, with annual global losses estimated in the tens of millions of cubic meters of timber volume due to storm damage. In Europe, a key region for timber production, wind damage alone affects approximately 46 million m³ of timber each year, representing about 46% of total disturbance-related losses and contributing to average annual economic costs of around €1.7 billion from windstorms and related disturbances. These figures underscore the scale of disruption, where major storms can amplify losses to €1-2 billion in direct timber value and associated expenses across affected countries.^[41]^[42] The timber industry faces immediate operational challenges from windthrow, including disruptions to planned harvest schedules as resources shift to urgent salvage logging, which incurs 10-30% higher costs than standard operations due to tangled stems and difficult access. Windthrown trees are prone to rapid quality degradation, such as blue staining from fungal invasion and structural damage that reduces usable wood volume, often lowering the value per cubic meter by 20-50% if not processed within months. This oversupply of lower-grade timber floods markets, triggering price fluctuations; for example, post-storm roundwood prices in the United States and Europe have declined by 1-4% annually on average, with sharper drops of up to 50% in severely impacted areas, affecting supply chains and profitability for sawmills and exporters.^[43]^[44]^[45] Regional events highlight the magnitude of these losses, such as the 1999 Lothar and Martin storms, which felled 193 million m³ of roundwood across France, Germany, Switzerland, and other countries—equivalent to two years of normal harvest volume in the affected regions and causing timber value losses exceeding €3 billion. In France and Germany specifically, these storms damaged over 140 million m³ combined, severely straining local industries and requiring multi-year salvage efforts.^[46] Forest insurance and government policies provide critical buffers against these economic shocks, covering timber value losses, salvage costs, and replanting expenses in countries like France and Sweden. However, uptake varies; following the 2005 Gudrun storm in Sweden, where many owners lacked coverage, the government disbursed approximately €300 million in compensation to stabilize the sector. European frameworks, including EU-coordinated response plans, facilitate insurance claims processing and market interventions to prevent price collapses, though challenges persist in insuring high-risk stands predisposed to wind exposure.^[44]^[47] Climate projections indicate that annual economic costs from forest disturbances in Europe could rise to €2.8–3.7 billion by 2076–2100 under different emissions scenarios (RCP4.5 and RCP8.5), driven largely by intensified windstorms.^[42]

Management and Mitigation Strategies

Silvicultural practices play a central role in reducing windthrow vulnerability by promoting stand stability and resilience. Thinning operations must be carefully managed to avoid increasing windthrow risk; for instance, maintaining spacings less than 2 meters in high-risk areas can decrease damage risk by providing mutual support among trees, without overly compromising growth.^[4] Diversifying species and age classes within stands enhances overall resistance, as mixed-species forests with deep-rooting trees like oaks or spruces are less prone to uniform failure compared to monocultures of shallow-rooted species such as poplars.^[4] Retaining windbreaks, such as irregular forest edges or buffer strips of mature trees, shields interior stands from prevailing winds; in coastal British Columbia, retention systems leaving trees within one tree-height of harvest edges effectively maintain protective cover.^[48] Technological aids enable proactive risk assessment and planning. Windthrow risk modeling tools, such as ForestGALES, integrate mechanistic and empirical data to calculate critical wind speeds for stands, achieving 70-80% accuracy in predicting damage vulnerability across landscapes.^[49] Geographic Information Systems (GIS) facilitate exposure mapping by overlaying topographic, soil, and wind pattern layers; for example, empirical models in mountainous forests use logistic regression within GIS to identify high-hazard zones based on slope and aspect.^[50] Early warning systems leverage meteorological forecasts from services like national weather agencies to alert forest managers of impending storms, allowing temporary measures such as securing equipment or delaying operations in exposed areas.^[4] Post-event responses focus on rapid recovery to minimize further losses and restore ecosystem function. Salvage logging protocols prioritize the removal of windthrown timber to prevent secondary issues like bark beetle infestations; in Finland, guidelines under the Forest Damage Prevention Act mandate salvage if damage exceeds 20 m³/ha for spruce (or 10 m³/ha for pine), using efficient harvesters to optimize productivity despite 20-30% higher costs compared to undamaged stands.^[43] Replanting emphasizes resilient species adapted to local wind regimes, such as those with strong anchorage, combined with natural regeneration to accelerate stand re-establishment; monitoring post-salvage windthrow, with thresholds like >20% damage triggering reassessment, ensures ongoing stability.^[48] Policy integration embeds these strategies within sustainable forest management frameworks. Certifications like the Forest Stewardship Council (FSC) and Sustainable Forestry Initiative (SFI) require risk assessments and adaptive practices in management plans, such as adjusting harvest boundaries to avoid high-exposure edges, aligning with broader goals of biodiversity and long-term productivity.^[48] Economic incentives, including subsidies for windfirming treatments like crown topping, encourage adoption of these measures in certified operations.^[48]

Historical and Global Perspectives

Notable Events and Storms

One of the earliest recorded major windthrow events in North America was the White Hurricane of 1913, which impacted Ontario and the broader Great Lakes region from November 7 to 10. The storm developed as a rapidly intensifying extratropical cyclone over Lake Superior, tracking southeastward across Lakes Huron and Erie with sustained winds of 70 mph (113 km/h) and gusts up to 90 mph (145 km/h). These conditions caused widespread uprooting and breakage of trees along shorelines and inland forests in southern Ontario, contributing to the storm's overall devastation that included blocked roadways and damaged infrastructure across the province.^[51]^[52] In Europe, the Great Storm of 1987 stands as a benchmark for windthrow damage in the United Kingdom, occurring on October 15–16. Originating in the Atlantic near the Bay of Biscay, the extratropical cyclone moved northeastward across southern England and into the North Sea, producing gusts exceeding 100 mph (161 km/h) in southeast England for several consecutive hours. The event felled an estimated 15 million trees, equivalent to approximately 4 million cubic meters of timber volume, with broadleaved species comprising the majority of losses in privately owned woodlands. Forestry assessments documented the damage through ground surveys, revealing that 72% of affected trees were in non-commercial settings, prompting immediate salvage operations by the Forestry Commission.^[53]^[54]^[55] More recently, Cyclone Christian in 2013, also referred to as St. Jude's Storm, caused extensive conifer blowdowns across northern Europe from October 27 to 28. The storm formed off Greenland and tracked eastward across the UK, Denmark, Germany, and Scandinavia, with peak gusts of 120 mph (194 km/h) recorded in southern Denmark and 99 mph (159 km/h) on the Isle of Wight. It resulted in the felling of around 10 million trees and damage to approximately 2 million cubic meters of standing timber, particularly impacting spruce and pine stands in commercial forests. Post-event evaluations using satellite imagery from EUMETSAT helped map the extent of blowdown areas, showing concentrated damage in coastal and upland regions.^[56]^[57] In 2022, Storm Eunice struck the UK on February 18, generating gusts up to 122 mph (196 km/h) and felling an estimated 8 million trees during a severe winter storm season, causing widespread disruption to forests and infrastructure.^[58] In 2023, Storm Ciarán affected western Europe on November 1–2, with gusts exceeding 100 mph (161 km/h) in parts of France, the UK, and Iberia, leading to significant localized windthrow, including hundreds of trees downed in areas like Jersey and Brittany.^[59]^[60] These notable events underscore the vulnerability of monoculture plantations to extreme winds and have influenced forestry practices globally. For instance, following the 1999 storms Lothar and Martin, which devastated over 180 million cubic meters of timber across France, Switzerland, and Germany with gusts up to 115 mph (185 km/h), European countries implemented policy shifts toward species diversification and structural improvements to enhance tree stability. In France, post-storm strategies included delaying timber market release to stabilize prices and promoting mixed-species stands to mitigate future windthrow risks, as detailed in UNECE forestry reports. Similar adaptations, informed by damage assessments from ground inventories and remote sensing, have been adopted in the UK and Scandinavia to build resilience against intensifying storm patterns linked to broader climate trends.^[61]^[46]^[62]

Regional Variations and Climate Influence

Windthrow exhibits significant regional variations influenced by local climate patterns, forest types, and disturbance regimes. In boreal forests of North America, windthrow is a recurring disturbance driven by maritime influences and extratropical storms, with return intervals varying from decades to centuries depending on stand age and soil conditions, often altering soil chemistry more substantially than other factors like nitrogen deposition.^[63]^[64] In contrast, Southeast Asian forests, particularly in coastal and mangrove areas, experience higher windthrow frequencies from tropical cyclones, where typhoon winds exceeding 32 m/s frequently damage degraded stands, leading to alternative forest dynamics in wind-sheltered versus exposed sites.^[65]^[66] Temperate European forests, especially in central and mountain regions, are prone to widespread windthrow from gales and storms, accounting for about 46% of natural disturbances, while Mediterranean ecosystems face compounded risks from windstorms interacting with seasonal droughts, creating canopy gaps in drought-prone pine plantations.^[67]^[68] Climate change is projected to exacerbate windthrow through intensified storm events and interacting stressors. According to IPCC assessments, tropical cyclone intensity is expected to increase by 5-10% by 2050 under high-emission scenarios, with higher peak wind speeds and rainfall, amplifying windthrow in vulnerable regions like Southeast Asia.^[69] In Europe and North America, extratropical storm tracks may shift poleward, leading to small but regionally variable increases in extreme wind speeds, with models projecting increases in disturbance rates due to warmer conditions.^[70]^[42] Droughts, increasingly frequent in warming climates, weaken tree anchorage and hydraulic systems, making forests more susceptible to wind damage; for instance, drought-stressed stands show positive interactions with storm strength, elevating stem breakage risks by up to 78% in carbohydrate reserves.^[71]^[72] Adaptation challenges vary by forest location, with coastal areas facing heightened vulnerability from intensified cyclones and sea-level rise, compared to inland forests where drought-wind synergies dominate. Coastal ecosystems, exposed to hurricanes and tornados, experience more frequent uprooting due to saturated soils post-rainfall, while inland temperate and boreal stands suffer from reduced wind resistance after prolonged dry periods.^[2]^[73] Long-term monitoring reveals increasing windthrow rates in warming climates; European Forest Institute reports indicate disturbances have significantly increased since the 1950s, with wind as the primary agent (46% of damage), and projections suggest further rises in annual losses by 2050 due to climate-driven vulnerability.^[74]^[75]^[76]

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Functionally, decaying wood is related to nutrient cycling through its role as either a sink or source of nutrients [9]. Coarse woody debris is also a site ...
[33]
Long‐term development of species richness in a central European ...
Aug 16, 2021 · Disturbances, such as windthrow, insect infestation, flooding, or fire, are a significant element of the natural forest dynamic (Čada et al., ...
[34]
Effects of forest windstorm disturbance on invasive plants in ...
Jul 11, 2019 · Invasive plant populations respond positively to light increase from windstorm-caused canopy damage, but are typically out-competed over time as ...
[35]
Salvage-Logging after Windstorm Leads to Structural and Functional ...
The retreat of late-successional species in favour of grasses can lead to structural and functional homogenization of habitat and to delayed succession towards ...
[36]
(PDF) Windthrow-induced changes in faunistic biodiversity in alpine ...
Aug 7, 2025 · During the observed period of succession following the first assessment after the storm, the species richness further increased by 17% in both ...
[37]
[PDF] Post‐windthrow salvage logging increases seedling and understory ...
While salvage logging shifted the distribution of stem heights to smaller sizes, it increased woody species seedling diversity by 33% and total plant richness ...
[38]
Two decades of arthropod biodiversity after windthrow show ...
Jan 9, 2025 · Wind disturbance with selective logging thus significantly increases arthropod biodiversity at the landscape scale (Bouget & Duelli, 2004; Thorn ...2 Materials And Methods · 3.2 Dynamics Of Functional... · 4 Discussion
[39]
Wind damages expected to increase in a warmer climate | slu.se
May 30, 2025 · The amount of timber yearly affected by such disturbances in Europe increased ten-fold between 1950 and 2020, from 10 million cubic meter to ...Storms And Rot · Risks After Harvest · High Risk Vs High Growth
[40]
Rising cost of disturbances for forestry in Europe under climate change
Sep 18, 2025 · Here we show that disturbance-induced losses for Europe's timber-based forestry could increase from the current €115 billion to €247 billion ...
[41]
Evaluation of Salvage Logging Productivity and Costs in ... - MDPI
The results revealed that the cutting productivity of windfalls was 19–33% lower than that of undamaged stems. The cutting costs of windthrown stems with a ...
[42]
The Management Response to Wind Disturbances in European ...
Nov 16, 2021 · The perspectives on windthrown timber differ throughout Europe, ranging from leaving trees on site to storing them in sophisticated wet storage ...Missing: origin | Show results with:origin
[43]
Unraveling the Impacts: How Extreme Weather Events Disrupt Wood ...
Sep 5, 2024 · Average annual wind damage contributes downward pressure on roundwood prices between 1% and 4% in the United States, and this effect is ...
[44]
The storm Lothar 1999 in Switzerland–an incident analysis
High wind speeds and heavy gusts were characteristic of both storms, which caused great damage to forests, buildings and infrastructures. More than 12 million m ...
[45]
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2024EF004742
[46]
[PDF] Windthrow Management SOP - Gov.bc.ca
Apr 27, 2023 · Windthrow damage at the site and landscape level requires a management strategy for Timber Sale License (TSL) development, both generally, and ...
[47]
Interview: how ForestGALES is the essential tool for wind risk
May 21, 2024 · ForestGALES is Forest Research's leading wind risk modelling tool, used across the UK and internationally. Here, Tom Locatelli, Senior ...
[48]
Application of GIS to Empirical Windthrow Risk Model in Mountain ...
This paper deals with an empirical windthrow risk model based on the integration of logistic regression into GIS to assess forest vulnerability to wind- ...
[49]
Remembering the November 1913 "White Hurricane"
Nov 7, 2013 · The simulation captured wind gusts over 80 mph and frequent waves to 36 feet on southern and western Lake Huron on the evening of November 9, ...Missing: 1930 Ontario windthrow extent path
[50]
White Hurricane – The Great Storm of 1913 | Escarpment Magazine
Hurricane strength winds of 90 mph drove blinding snow and sleet, piling waves into roaring black 40-foot mountains that mauled vessels and shorelines. Giant ...
[51]
The Great Storm of 1987 - Met Office
With winds gusting at up to 100mph, there was massive devastation across the country and 18 people were killed. About 15 million trees were blown down.
[52]
[Archive] The 1987 storm: impacts and responses - Forest Research
Mar 31, 1989 · Broadleaved trees predominated and 72% of the damage occurred to privately owned woodlands and trees. The Forestry Commission set up a Forest ...
[53]
Revisiting The Great Storm Of 1987 | the Blackout report
Oct 16, 2020 · Impact Of The Great Storm. The ferocious winds damaged buildings across the country, while 15 million trees (4 million m3) were blown over ...Missing: volume | Show results with:volume
[54]
St Jude storm may have killed around 10 million trees - The Guardian
Nov 29, 2013 · The amount of standing timber affected is approximately 2 million metres cubed, measured against an annual UK harvest of 10.5 million metres ...
[55]
Storm St Jude batters the UK | EUMETSAT - User Portal
Gusts of 159km/h (99mph) were recorded on the Needles, Isle of Wight as the storm swept west to east across Southern England, the Midlands and parts of South ...
[56]
Biggest windthrow volumes - Timber Online
Timber-Online's editorial team gathered data on the biggest windthrow volumes recorded in European forests since 1990 and ranked them.
[57]
[PDF] Effects of the December 1999 Storms on European Timber Markets
Highlights. • Severe windstorms felled 193 million m3 of roundwood in December 1999, the equivalent of 2 years' harvest in affected countries.
[58]
25 Years After Anatol, Lothar and Martin: Lessons Learned ...
According to the French Federation of Insurance Companies (FFSA), insured losses totaled about EUR 6.8 billion (including hazards covered by the French public ...
[59]
Relative frequency of windthrow return intervals for each ...
Therefore, our results indicate that windthrows could potentially alter the North American boreal forest soil chemistry much more than elevated N deposition ...
[60]
Windthrow modelling in old-growth and multi-layered boreal forests
May 10, 2016 · Windthrow is a recurring disturbance process in regions that are influenced by maritime climates, including boreal forests.
[61]
Forest dynamics where typhoon winds blow - Wiley Online Library
Dec 14, 2024 · Wind-sheltered forests had rugged structures due to higher vulnerability to tropical cyclones. Forests had two alternative strategies ...
[62]
Implications of tropical cyclones on damage and potential recovery ...
Many natural forests in Southeast Asia are degraded following decades of logging. Restoration of these forests is delayed by ongoing logging and tropical ...
[63]
Natural disturbances risks in European Boreal and Temperate ...
Apr 1, 2022 · The economic losses have been estimated to be around 800 million euros per year (Woodward et al., 1998). However, this estimation is based ...
[64]
Effects of Windthrows on Forest Cover, Tree Growth and Soil ... - MDPI
Jun 22, 2021 · Windthrows reduced tree cover and enhanced growth, particularly in the P. halepensis site, which was probably more severely impacted.
[65]
[PDF] Weather and Climate Extreme Events in a Changing Climate - IPCC
... wind speed changes are expected to be small, although poleward shifts in the storm tracks could lead to substantial changes in extreme wind speeds in some ...
[66]
Chapter 11: Weather and Climate Extreme Events in a Changing ...
Widespread observed and projected increases in the intensity and frequency of hot extremes, together with decreases in the intensity and frequency of cold ...
[67]
Coupled effects of wind-storms and drought on tree mortality across ...
In some stands, we found positive interaction between drought and storm strength most likely because drought weakens trees, and they became more prone to stem ...
[68]
Windthrow causes declines in carbohydrate and phenolic ...
May 28, 2024 · Windthrown trees experienced a decrease of 78% and 37% of sugar and phenolic concentrations, respectively. This strong decline was especially pronounced for ...
[69]
[PDF] The Influence of Forest Management on Vulnerability of Forests to ...
Soil saturation is an important factor affecting the prob- ability of windthrow. When hurricanes or other wind storms pass through an area following periods ...
[70]
Increased forest disturbances require better reporting and data ...
Mar 7, 2023 · A new EFI Policy Brief looks at the key trends in forest disturbances since the 1950s and makes recommendations for better reporting and data collection.Missing: rates warming
[71]
Impacts on and damage to European forests from the 2018–2022 ...
Jan 6, 2025 · This study consolidates data on drought and heat damage in European forests from 2018 to 2022, using Europe-wide datasets.
[72]
[PDF] Global warming and windstorm impacts in the EU
By 2050, wind storm annual losses are projected to grow to ... Even though that wind hazard and risk will likely not strongly rise with global warming ...