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Recorded storm damage in Swedish forests 1901–2000
Abstract
Severe storm damage has been a recurring problem to the Swedish forestry sector since, at least, the start of the19th century. This short communication presents a regionally resolved time-series of storm damage in Swedish forests during the last century. Data on storm damage have been gathered from the National Board of Forestry, the Regional Forestry Boards and scientific reports.Storm damage in Swedish forests seems to have increased during the century with a peak around the 1980s. In total 110 million m3 forest were destroyed by 77 recorded wind storms, with the severe storms in 1954 and 1969 accounting for 49% of the total damage. Reported damage in southern Sweden was normalised against the area of productive forest with trees older than 40 years, for inter annual comparisons. The geostrophic wind was used to describe the regional wind direction during the storm events. Most damage occurred during NNW to SW winds, and by winds from NNE. Apart from a possible shift in storm intensity and frequency, the increase in storm damaged trees can be attributed to changes in regeneration and thinning regimes, variations in storm damage reporting system, increase in forest cover and various damage to root architecture.
... The primary purpose of this study was to present a flexible model framework for analyzing longitudinal wind-damage data that adequately addresses autocorrelation and inaccurate or incomplete data. This framework is particularly useful for long-term forest datasets, such as those maintained by universities, institutes, and federal or local governments (Nilsson et al., 2004;Usbeck et al., 2010;Brázdil et al., 2018). ...
... where D i is a binary variable taking a value of 1 if wind damage occurred in the target stands during the ith wind event and 0 otherwise, and is assumed to follow a Bernoulli distribution Bern(p i ); p i is the probability that the ith wind event will cause damage in the target stands; conditions during a wind event are described by wind speed (ve i ; continuous variable expressed in m s -1 ), mean stand volume (vo i ; continuous variable expressed in m 3 ha -1 ) for a decade (de i ; discrete variable), wind direction (di i ; discrete variable), and season (s i ; discrete variable); e 1 -e 2 are functions describing the effects of wind direction and season, respectively, whose values are autocorrelated with their neighboring values (explained below in detail); b 0 is an intercept term; b 1 and b 2 are the model parameters relating wind speed and mean stand volume to wind-damage probability, respectively; and logit is a logit function. Wind direction was included in the model because wind direction can modify the impact of winds depending on topographic and geographic conditions or the degree of acclimation of trees to wind (Ennos 1997;Nilsson et al., 2004). Season was included because it modifies the impact of wind through changes in soil conditions and phenology, i.e. the presence or absence of deciduous leaves (Nilsson et al., 2004;Usbeck et al., 2010;Brázdil et al., 2018). ...
... Wind direction was included in the model because wind direction can modify the impact of winds depending on topographic and geographic conditions or the degree of acclimation of trees to wind (Ennos 1997;Nilsson et al., 2004). Season was included because it modifies the impact of wind through changes in soil conditions and phenology, i.e. the presence or absence of deciduous leaves (Nilsson et al., 2004;Usbeck et al., 2010;Brázdil et al., 2018). Mean stand volume was included because the impacts of winds can vary with developmental status (Peterson, 2000;Albrecht et al., 2012). ...
Aim of study: To develop a statistical model framework to analyze longitudinal wind-damage records while accounting for autocorrelation, and to demonstrate the usefulness of the model in understanding the regeneration process of a natural forest.
Area of study: University of Tokyo Chiba Forest (UTCBF), southern Boso peninsula, Japan.
Material and methods: We used the proposed model framework with wind-damage records from UTCBF and wind metrics (speed, direction, season, and mean stand volume) from 1905–1985 to develop a model predicting wind-damage probability for the study area. Using the resultant model, we calculated past wind-damage probabilities for UTCBF. We then compared these past probabilities with the regeneration history of major species, estimated from ring records, in an old-growth fir–hemlock forest at UTCBF.
Main results: Wind-damage probability was influenced by wind speed, direction, and mean stand volume. The temporal pattern in the expected number of wind-damage events was similar to that of evergreen broad-leaf regeneration in the old-growth fir–hemlock forest, indicating that these species regenerated after major wind disturbances.
Research highlights: The model framework presented in this study can accommodate data with temporal interdependencies, and the resultant model can predict past and future patterns in wind disturbances. Thus, we have provided a basic model framework that allows for better understanding of past forest dynamics and appropriate future management planning.
Keywords: dendrochronology; tree regeneration; wind-damage probability model; wind disturbance.
Abbreviations used: intrinsic CAR model (intrinsic conditional autoregressive model); MCMC (Markov chain Monte Carlo); 16 compass points = N, NNE, NE, ENE, E, ESE, SE, SSE, S, SSW, SW, WSW, W, WNW, NW, NNW (north, north-northeast, northeast, east-northeast, east, east-southeast, southeast, south-southeast, south, south-southwest, southwest, west-southwest, west, west-northwest, northwest, north-northwest, respectively); UTCBF (the University of Tokyo Chiba Forest).
... A 60-year-long record of storm damage statistics over Sweden was extracted from the country-level European Forest Institute storm damage database from 1951 to 2010 ( Nilsson et al., 2004;Schlyter et al., 2006;Bengtsson and Nilsson, 2007;Gardiner et al., 2010). We refined this dataset with regional information. ...
... Within the study domain, this approaches reduced the standing biomass mainly in western Norway (not shown). Subsequently, the simulation experiment continued from 1951 to 2010, the period for which damage reports are available ( Nilsson et al., 2004;Schlyter et al., 2006; Bengtsson and Nilsson, 2007; Gardiner et al., 2010). The years 1981 to 2000, which were used for parameter tuning, were excluded from the evaluation. ...
... Figure 5. Sensitivity of the simulated storm damage over Sweden between 1981 and 2000 for different values for the relaxation parameter (R f ) and the gust factor adjustment G adj (a). Observed storm damage is extracted from Nilsson et al. (2004), Schlyter et al. (2006, Bengtsson and Nilsson (2007), and Gardiner et al. (2010). The relative model simulation error (calculated as (estimation−observation) / estimation) for the best-tuned case (b). ...
Earth system models (ESMs) are currently the most advanced tools with which to study the interactions among humans, ecosystem productivity, and the climate. The inclusion of storm damage in ESMs has long been hampered by their big-leaf approach, which ignores the canopy structure information that is required for process-based wind-throw modelling. Recently the big-leaf assumptions in the large-scale land surface model ORCHIDEE-CAN were replaced by a three-dimensional description of the canopy structure. This opened the way to the integration of the processes from the small-scale wind damage risk model ForestGALES into ORCHIDEE-CAN. The integration of ForestGALES into ORCHIDEE-CAN required, however, developing numerically efficient solutions to deal with (1) landscape heterogeneity, i.e. account for newly established forest edges for the parameterization of gusts; (2) downscaling spatially and temporally aggregated wind fields to obtain more realistic wind speeds that would represents gusts; and (3) downscaling storm damage within the 2500 km2 pixels of ORCHIDEE-CAN. This new version of ORCHIDEE-CAN was parameterized over Sweden. Subsequently, the performance of the model was tested against data for historical storms in southern Sweden between 1951 and 2010 and south-western France in 2009. In years without big storms, here defined as a storm damaging less than 15 × 106 m3 of wood in Sweden, the model error is 1.62 × 106 m3, which is about 100 % of the observed damage. For years with big storms, such as Gudrun in 2005, the model error increased to 5.05 × 106 m3, which is between 10 and 50 % of the observed damage. When the same model parameters were used over France, the model reproduced a decrease in leaf area index and an increase in albedo, in accordance with SPOT-VGT and MODIS records following the passing of Cyclone Klaus in 2009. The current version of ORCHIDEE-CAN (revision 4262) is therefore expected to have the capability to capture the dynamics of forest structure due to storm disturbance on both regional and global scales, although the empirical parameters calculating gustiness from the gridded wind fields and storm damage from critical wind speeds may benefit from regional fitting.
... qq qq qq qq q q q q q q q q q q q q q q q q q q q q q 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 (R f ) and the gust factor adjustment G adj . Observed storm damage is extracted from (Nilsson et al., 2004;Schlyter et al., 2006;Bengtsson and Nilsson, 2007;Gardiner et al., 2010) q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q Relaxation factor, R f (unitless) 6.0 6.0 6.0 6.0 6.0 ...
... Within the study domain, this approaches reduced the standing biomass mainly in western Norway (not shown). Subsequently, the simulation-experiment continued from 1951 to 2010, the period for which damage reports are available(Nilsson et al., 2004;Schlyter et al., 2006;Gardiner et al., 2010). The years 1981 to 2000 which were used for parameter tuning were excluded from the evaluation. ...
... Comparison of the storm damage simulated by the ORCHIDEE-CAN and the annual primary wood damage over the Sweden from 1951 to 2010. Observed storm damage is extracted from(Nilsson et al., 2004;Schlyter et al., 2006;Bengtsson and Nilsson, 2007;Gardiner et al., 2010) The dashed-line area is the period from 1981 to 2000, which was selected for parametrization. The RMSE of the estimated storm damage is 1.35 ×10 6 m 3 for the parametrization period and 5.05×10 6 m 3 during the evaluation period. ...
Earth System Models (ESMs) are currently the most advanced tools with which to study the interactions between humans, ecosystem productivity and the climate. The inclusion of storm damage in ESMs has long been hampered by their big-leaf approach which ignores the canopy structure information that is required for process-based wind throw modelling. Recently the big-leaf assumptions in the large scale land surface model ORCHIDEE-CAN were replaced by a three dimensional description of the 5 canopy structure. This opened the way to the integration of the processes from the small-scale wind damage risk model ForestGALES into ORCHIDEE-CAN. The resulting enhanced model was completed by an empirical function to convert the difference between actual and critical wind speeds into forest damage. This new version of ORCHIDEE-CAN was parametrised over Sweden. Subsequently, the performance of the model was tested against data for historical storms in Southern Sweden between 1951 and 2010, and South-western France in 2009. In years without big storms, here defined as a storm 10 damaging less than 15×106m3 of wood in Sweden, the model error is 1.62×106m3 which is about 100% of the observed damage. For years with big storms, such as Gudrun in 2005, the model error increased to 5.05×106m3 which is between 10% and 50% of the observed damage. When the same model parameters were used over France, the model reproduced a decrease in leaf area index and an increase in albedo, in accordance with SPOT-VGT and MODIS records following the passing of Cyclone Klaus in 2009. The current version of ORCHIDEE-CAN (revision 4262) is therefore expected to have the capability 15 to capture the dynamics of forest structure due to storm disturbance both at regional and global scales, although the empirical parameters calculating gustiness from the gridded wind fields and storm damage from critical wind speeds may benefit from regional fitting.
... Likewise, in Switzerland, windthrow was attributed to an increase in temperature, precipitation rate and wind speed [44]. In Sweden, strong gusts of wind from north-northwest and north-northeast [45] were considered to be the cause of damage [18]. ...
... Considering the fact that tree stands under the age of 40 are not seriously affected by windthrow, it could be stated that, until this age, trees grow sufficiently tall are capable of withstanding strong winds [45]. In the case of tree stands affected by large-scale windthrow, approximately 50% of the surface and volume affected are over 100 years old. ...
Windthrow is a phenomenon that causes major changes to tree stand evolution by blowing down or breaking either isolated trees or entire tree stands, with a strong ecological, social and economic impact. Both scattered and large-scale windthrow occurred in spruce (Picea abies (L.) Karst.) tree stands of Romania. They affected surfaces of various dimensions from harvestable forests. Such a phenomenon took place in the Curvature Carpathians in February 2020. Large-scale windthrow occurred in this area in 1995 as well, in the upper watershed of Bâsca river. Using the climate data from February 2020, this paper aims to identify the manner in which factors such as climate and site conditions together with tree stand characteristic and the anthropogenic factor impacted and influenced the occurrence of windthrow. The results showed that the intensity of this phenomenon had maximum effects when the wind coming from north/northeast reached the maximum speed of 32 m·s⁻¹. Pure spruce tree stands situated on slopes with an inclination between 16 and 30° were mainly affected. Their position was counter to the wind direction, at an altitude between 1300 and 1500 m, on cambisols and spodosols. The analysis and statistical interpretation of data in the case of scattered and large-scale windthrow from the two management units showed that the same factors studied influence the variation of windthrow intensity in a different manner, or sometimes they do not influence it at all or they can only account for a small part of this variation.
... An example of an index that represents the risk of frost damage is the daily difference between cold hardiness level and the daily minimum temperature (Rammig et al., 2010). The temperature sum needed before budburst is also of key importance in determining frost risk (Nilsson et al., 2004). Different thresholds for daily mean temperature and accumulated temperature sum are used to model budburst, but an example of an frost damage index that includes budburst is the frequency of minimum temp < 0 • C following an accumulation of 170 • -days > 5 • C (starting 1 Jan) for Norway spruce in southern Sweden Schlyter et al., 2006). ...
... The studies on storm damage typically include rather complex storm damage models. However, some climate indices could be derived from the wind damage models, e.g., annual maximum wind speed (Blennow et al., 2010a(Blennow et al., , 2010b, average wind distribution (Nilsson et al., 2004), and maximum value of 30 min mean wind speed for a specified period a time (e.g. 6 h) (Chen et al., 2018). ...
Climate information is an important support for national adaptation plan processes, but there is at the same time a general desire that climate information should be more relevant and appropriate in relation to decision-making contexts. An initial step in such a development towards tailored climate information would be to understand the currently available climate indices, their definitions and contexts. This study systematically reviews the scientific literature on climate indices and factors related to specific climate impacts, and in this way identifies currently available climate indices for Swedish forestry and agriculture. The identified indices are analysed relative to climate change impact categories from the vulnerability assessments and adaptation plans set out by the Swedish Forest Agency and the Swedish Board of Agriculture, to indicate development potentials and research gaps in climate indices.
The review identifies 79 definitions of climate indices for forestry and 63 indices for agriculture in Sweden. The reviewed literature has employed or developed climate indices for only 11 of the 25 types of climate impact emphasised as important by the two sectoral authorities. Most of the climate indices identified have been adopted for use in modelling forest growth or crop growth and productivity. The results of the review found indices lacking for a substantial number of impacts that are relevant for Swedish forestry and agriculture. The study shows that scientific literature on climate indices to a very limited degree addresses the specific tailoring of climate indices.
Potential reasons for the lack of climate indices are discussed, and the study suggests that there is a need to continue climate model development such that the models better represent relevant processes, to advance research on the co-design of indices together with sectoral stakeholders, and to enhance collaboration between adaptation, impact modelling and climatology research. The results of the study may be used in future research to analyse if and how the identified climate indices can be actionable for different stakeholders, and as a foundation to examine the demands and feasibilities of developing new tailored climate indices.
... Large catastrophic windthrow events can be a significant contributor to overall wind damage in a landscape from specific storms (Dobbertin, 2002, Peterson, 2007 or from cumulative effects over centuries (Schelhaas et al., 2003, Nilsson et al., 2004, Knapp and Hadley, 2012. There is little that can be done to prevent such damage, so it is generally acknowledged that managers need to focus on endemic windthrow and management practices that can decrease susceptibility of forests to wind damage. ...
... Catastrophic windthrow from major storm events can represent a sizeable proportion of total wind damage over long time periods. For example, two storms were responsible for 49% of wind damage over a century in Sweden (Nilsson et al., 2004); storms "Vivian" and "Lothar" only a decade apart (1990 and 1999, respectively) caused widespread damage in western and central Europe-the latter affecting 37% of long-term inventory plots in Switzerland (Dobbertin, 2002); and "Typhoon Freda" (October 12, 1962) caused unprecedented wind damage to forests on the PNW coast from California to British Columbia (Knapp and Hadley, 2012). Large areas of even-aged western hemlock-dominated forests on northern Vancouver Island originated from windthrow during a major storm on December 23, 1907(The Daily Colonist, 1907. ...
Conservation of biological diversity is a key criterion in all sustainable forest management certification schemes. A common strategy for maintaining stand-level diversity after forest harvesting on the coast of British Columbia is variable retention. This approach leaves diverse amounts, types and patterns of tree retention, ranging from single trees to large patches of the original forest. Variable retention contributes to diversity of stand structure; however, wind damage may have a significant effect on the value of retention for different organisms. Wind damage also influences perception of the approach by resource managers and the public. This study quantified the extent of wind damage on forest edges, patches and dispersed individual trees after harvesting retention cutblocks. We also investigated the qualitative and quantitative factors associated with wind damage. The geographic distribution of the study facilitated evaluation of regional variation in windthrow. We sampled 172 harvested areas over a 6-year period from southern Vancouver Island (VI) to Haida Gwaii (Queen Charlotte Islands). The study showed regional differences in wind damage for cutblocks after 2–5 wind seasons. Wind damage was measured as the total percentage of windthrown trees, broken stems and leaning trees within 25 m of forest edges. Average wind damage to cutblock edges (16%) ranged from 11% on southern VI to 25% on the northwest coast of VI. There was a similar regional trend with wind damage to trees retained in large patches and in smaller groups. The average damage along the edges of retention patches over 1 ha (24%) was lowest for southern VI and the BC coastal mainland (16%) and highest for Haida Gwaii (45%). Wind damage to entire groups averaging 0.22 ha in size (37%) varied from 23 to 53% among study areas. For strips of retained timber, wind damage averaged 32% in the 25 m edge sampled. Windward edges were more vulnerable to windthrow than other boundary exposures and damage differed significantly among biogeoclimatic subzones. Topographically exposed locations such as ridge crests and upper slopes experienced more wind damage than middle and lower slopes. The amount of wind damage also increased with increasing stand height and fetch distance. The distance that windthrow penetrated a stand edge was affected by some of the same factors as percent damage. Penetration along cutblock edges varied regionally from 6 m to 20 m. Our results suggest that designing variable retention for local site, stand and wind exposure conditions can reduce the potential for wind damage.
... However, during the last few decades the intensity and frequency of disturbances caused by storms, droughts, fires, pest insect outbreaks or wet snow events in central European forests has risen measurably (Schelhaas et al., 2003;Nilsson et al., 2004). Thus, approximately 16,000 ha or 0.15% of the total forest area in Germany are annually disturbed considering the time between 1950(EFI, 2013. ...
... At the European level such disturbances are equivalent to 8% of the total annual fellings (Schelhaas et al., 2003). Natural forest disturbances are thus a relevant aspect of central European forest management (Schelhaas et al., 2003;Nilsson et al., 2004;Majunke et al., 2008;Mantau, 2012;Albrecht et al., 2013;Kraus and Krumm, 2013). ...
... Auf der Basis bisheriger Ergebnisse aus Modellsimulationen ist es schwierig zu beurteilen, ob und wie sich eine ändernde nordatlantisch-europäische Sturmaktivität auf Sturmschäden in Wäldern auswirken könnte, da Faktoren wie Landnutzungsänderungen, Änderungen des Bestandesalters und Änderungen waldbaulicher Methoden schwer absehbar sind (z. B. MAYER und SCHINDLER, 2002;NILSSON et al., 2004;SCHINDLER und MAYER, 2003;SCHLYTER et al., 2006). Zudem ist in meist mit Wäldern bestocktem, topographisch komplexem Gelände die bodennahe mit der übergeordneten, großräumigen Strömung über eine Vielzahl von Mechanismen gekoppelt (WHITEMAN und DORAN, 1993). ...
... Diese Prozesse werden aufgrund ihrer kleinen zeitlichen und räumlichen Skalen bei vielen Untersuchungen zur Sturmwirkung auf Wälder bisher nicht berücksichtigt. Allgemein bekannt ist, dass marginale Änderungen der Sturmaktivität zu überproportional hohen Sturmschäden in Wäldern führen können (SCHLYTER et al., 2006) und dass wenige extreme Stürme extreme Schäden verursachen können (NILSSON et al., 2004). So könnte beispielsweise ein Anstieg der Böengeschwindigkeit um 2 Prozent in den Niederlanden zu einer Erhöhung der Gebäudeschäden um 50 Prozent führen (DORLAND et al., 1999). ...
... Investigations may centre on the impacts of individual windstorms (Bründl and Rickli, 2002;Fink et al., 2009;Nekovář and Valter, 1998;Schüepp et al., 1994;Usbeck et al., 2012), while several papers have addressed their impacts on forests in terms of decades or centuries. For example, Nilsson et al. (2004) analysed storm damage to Swedish forests during the 20th century. In Switzerland, Usbeck et al. (2010) demonstrated increasing storm damage to forests from 1858 to 2007; Stucki et al. (2014) created a catalogue of high-impact windstorms taking place after 1859; and Usbeck (2014) described forest damage done by winter storms in the 1865-2014 period. ...
... This is in general agreement with Usbeck et al. (2010), who found 17 times greater forest damage (expressed in m 3 of timber) caused by winter windstorms during the 1958-2007 period compared to the years 1908-1957 for Switzerland, and 22 times greater compared to the 1858-1907 period. Nilsson et al. (2004) also reported increased windstorm damage in Swedish forests during the 20th century, peaking around the 1980s; working with 77 recorded windstorms, those in 1954 and 1969 accounted for an extraordinary 49% of the total damage. This study is consistent with these findings of overall increases in forest damage, and this phenomenon is evident over an even more extended period of time, i.e. covering 215 years, back to 1801. ...
The long-term relationship between windstorms and forest disturbances in the Czech Lands is analysed in this
paper, covering a very long period of 215 years (1801–2015). Based on documentary evidence and instrumental
records, long-term series of severe windstorms in the summer half-year (April–September) and in the winter halfyear (October–March) are compiled. Severe windstorms were more frequent in the 1820s–1840s, 1900s–1930s, and 1960s–2000s, less so in the latter half of the 19th century and in the 1940s–1950s. Their long-term
variability is revealed with three differently-created series of forest damage for the periods of 1801–1900,
1900–1980 and 1963–2015. Based on these comparisons, 14 windstorms that did outstanding damage to forests are selected: 12 occurred in the winter half-year and two in July. They are further investigated with respect to their meteorological character and the damage done. In this sample, the high-impact winter half-year windstorms are typically related to very distinct (> 45 hPa) pressure gradients between low pressure systems over the North/Norwegian Sea and high pressure systems south-west of the Iberian Peninsula, which exhibits an eastward-shifted and tilted NAO pattern, inducing the passage of frontal waves across the Czech Lands. High temperatures arising from south-westerly airflow and wet ground before windstorms provided conditions conducive to extensive windthrow in forests, sometimes with damage exacerbated by subsequent bark-beetle calamities. The increase in windstorms with outstanding forest damage after 1950 may be attributed in part to the negative consequences of forest management that prioritises high, short-term profits over ecological well-being.
... Unfortunately, climate extremes have been affecting forests rapidly and frequently throughout Europe in the past decade [1,2]. Strong winds, followed by insect outbreaks or devastating forest fires, have left heavy ecosystem side effects and disruptions of abiotic conditions [3][4][5][6][7]. ...
Forests in Croatia are characterized by higher levels of biodiversity in species composition. Three significant events occurred in Croatian forests over the past ten years, all of which have a common denominator—sanitary felling. The challenge in the sustainable development of forests started with the ice storm of 2014 that amounted to damage and raised costs in forest stands to EUR 231,180,921. The second challenge was in 2017 when the bark beetle outbreak occurred in the Gorski Kotar region. In December 2017, a windstorm in the same area caused damage to approximately 500,000 m3 of wood stock. The third climate extreme was in the summer of 2023 when three storms with strong winds and heavy rain damaged even-aged forests of common beech and pedunculated oak. The damage was substantial: 3,954,181 m3 of timber was mostly broken and destroyed across 21,888.61 ha of area, and the most damage was in the pedunculate oak forests of Slavonia, i.e., Quercus robur subsp. Slavonica, at 1,939,175 m3. For the main meteorological stations in lowland Croatia, data on precipitation amounts (mm) and wind speeds (m/s) were collected for the period 1981–2023, and the results of our analysis for the last decade are presented. Meteorological drought was analyzed using the rain anomaly index RAI. Data regarding open space fires in the Mediterranean karst area of Croatia were collected from the Croatian Firefighting Association, and the calculation of the burned area index (BAI) was determined. Throughout the entire area of Gorski Kotar County, a sample of permanent plots was set and used to assess the extent of forest damage from the ice storm in 2014 and for the establishment of permanent monitoring of the recovery of trees and forests damaged by the ice storm. The monitoring of bark beetles in the Gorski Kotar region started in 1995 and is still in progress. The aftermath of bark beetle outbreaks in two uneven-aged silver fir stands was studied after a bark beetle outbreak and a sanitary felling of 4655.34 m3. In the area of lowland Croatia, a statistically significant and positive correlation was found between sanitary fellings, maximum wind speeds, and rain anomaly indices in even-aged forests. In conclusion, sustainable development will be at risk due to difficult recovery, rising costs, and overall climate change in the years to come.
... In recent decades, European coniferous forests, particularly Norway spruce forests, have witnessed a surge in windthrow disturbances, intensifying in both regularity and impact (Nilsson et al., 2004;Seidl et al., 2011). This phenomenon, coupled with the activities of the Eurasian spruce bark beetle (Ips typographus L.), constitutes a dual threat to these ecosystems. ...
This thesis examines the impact of climate-induced drought stress and bark beetle infestations on European spruce forests, particularly the Eurasian spruce bark beetle (Ips typographus L.) attacks on Norway and Siberian spruce. Utilizing satellite remote sensing, ground truth, and meteorological data, the study explores tree health assessment during various bark beetle infestation phases.
Four scientific publications form the core of this thesis. Two studies (Trubin et al., 2023; 2024) apply PlanetScope multispectral imagery and ground truth data to identify forest spectral characteristics before and during early bark beetle attacks. Key findings highlight the effectiveness of specific spectral vegetation indices (Enhanced Vegetation Index (EVI) and Visible Atmospherically Resistant Index (VARI)) in early detection of beetle-related tree decline, offering a novel approach to forest health monitoring.
The other two studies (Trubin et al., 2022 and Pirtskhalava-Karpova et al., 2024) focus on modeling tree mortality using meteorological variables. These studies identify key climatic factors influencing annual tree loss in forests with different spruce species. Results enhance predictive models for bark beetle outbreaks and highlight climatic patterns predictive of potential infestations.
Overall, this thesis contributes significantly to forest management and conservation strategies. By integrating satellite imagery with terrestrial and climatic data, it provides a comprehensive framework for early detection and continuous monitoring of bark beetle infestations. This proactive methodology aids in identifying vulnerable and affected areas, enabling timely and targeted interventions to reduce damage. Moreover, the developed mortality models using climatic variables empower forest managers to better anticipate and prepare for potential outbreaks, optimizing resource management and response tactics.
... The frequency and intensity of windthrow disturbances (that is, the consequences of a wind storm that breaks or overturns trees over large areas) of forest stands in Europe and around the world have been increasing since the late twentieth century (Nilsson et al. 2004;Senf and Seidl 2021). Accordingly, research is now targeting not only the consequences of stand disturbance but also various ways to support stand recovery (Schönenberger 2002;Hotta et al. 2021;Wohlgemuth et al. 2017). ...
The usual practice following a windthrow event is salvage logging of all damaged trees. This study was carried out in a pine stand affected by storms with varying disturbance severities in which no salvage logging was performed. Epigeic carabids(Coleoptera) were the test taxon. How does windthrow severity and disturbance legacies affect the abundance, richness and life traits of carabid assemblages? Two hypotheses were formulated: (1) the more severe the disturbance, the higher the abun-dance and species richness, and the lower the proportion of late-successional fauna in carabid assemblages, and (2) pine tree crowns lying on the ground support a higher proportion of late-successional carabid species, the effect of which should be more pronounced in more severely disturbed stands but will decrease as needles fall off over the next 3 years. To test the first hypothesis, 3 degrees of stand disturbance were distinguished. Both hypotheses were partially supported. Simultaneously, it was demonstrated that the importance of the leaf area index for carabids decreased over the 3 years, while the significance of the soil respiration rate and soil humidity increased. During the 3 years, the percentage of carabid forest species living under the fallen tree crowns remained at the same level. The findings indicate that there is a rationale for leaving fallen trees in place together with their crowns, while in tree stands where salvage logging is performed, whole crowns should be leftcut-off from trunks to provide shelter for forest species
(18) (PDF) Leaving windthrown stands unsalvaged as a management practice for facilitating late-successional carabid assemblages. Available from: https://www.researchgate.net/publication/367361151_Leaving_windthrown_stands_unsalvaged_as_a_management_practice_for_facilitating_late-successional_carabid_assemblages [accessed Jan 24 2023].
... Samuelsson et al., 2012;SMHI, 2014;Eriksson et al., 2015). Concerning the impact of windstorms, during the last half century there is a clear trend towards increasing wind damage Nilsson et al. (2004), Holmberg (2005), Nilsson (2008) despite the lack of a corresponding trend towards a more severe wind climate (see section 3). Thus, the main drivers for the increase of wind throw is instead increased forest area, more dense forests and changing forest management practices, as well as the trends toward less ground frost and wetter soils during the main storm season (Eriksson et al., 2015). ...
This report is a synthesis about climate extremes in Sweden. It addresses observed and possible future changes in major climate variables related to pre�cipitation, floods, droughts, wind and storminess inclu�ding thunderstorms and tornadoes, hailstorms, ice storms, freezing rain, heat waves and cold spells.
... Looking at the whole epiphyte-host system, how much impact does the increased frontal area and epiphyte load have on the swaying of the trees? The movement of the crown of tall trees is probably mainly initiated by the collective area the leaves expose to the wind (Duryea et al. 2007, Nilsson et al. 2004. Whether epiphytes significantly increase the exposed surface in comparison to the area of tree foliage remains unclear. ...
Several studies of hurricane damage on epiphyte communities implied that epiphytes might be in danger of being blown off their host when subjected to strong wind. There is very limited knowledge about the mechanical impact that wind may have on epiphytes. Using a wind-triggered camera set-up, we observed how epiphytic tank bromeliads are affected by wind. Despite offering a relatively large area of ‘attack’ to the airflow, bromeliads moved relatively little themselves. Rather than being directly moved by wind, the bromeliads in the upper crown of tall trees moved with the sway of the branches. Only when the substrate did not move, bromeliads with long broad leaves showed considerable disturbance due to wind. Our observations underline the complexity of the system and emphasise that our current understanding of the mechanical aspects of the epiphyte–host system is still very limited.
... Sugar (fructose, glucose, and sucrose) is used as the primary source of energy when bears emerge from the den during the late winter season [6,15]. A single black bear damaged 60-70 trees during foraging in the moist forest of western Washington [16]. Supplemental food sources and lures were used during the spring months to decrease forest (trees) damages. ...
Tree damage is one of the destructive behaviors of the Asiatic black bear (Ursus thibetanus G. (Baron) Cuvier, 1823), and this type of damage causes great economic loss to the forest. A survey about Himalayan white pine (Pinus wallichiana (A. B) Jacks, 1836) damages was conducted at Kaghan Valley, District Mansehra, Khyber Pakhtunkhwa, Pakistan. Field surveys were carried out within five major sites of Kaghan Valley, including Manshi reserve forest, Kamal Bann reserve forest, Malkandi reserve forest, Noori Bichla reserve forest, and some Guzara forests. Line transects and diameter at breast height (DBH) methods were selected for data collection. Eighteen transects were placed in different sites of the valley. A total of (n = 201) affected trees were observed from eighteen transects, along with a total population of 1081 trees with the encounter rate (ER: 0.657) and the mean DBH is x¯ = 71.97 cm. Among total damages, the most severe (n = 39: 19.4%) were fully damaged with a greater encounter rate. Bark stripping was made during the late winter season and used as foodstuff when natural food is limited in the area. In severe cases, the bear-stripped bark encircles from the entire tree trunk, which results in the drying of trees and, finally, falls. Among all five sites, Manshi reserve forest was greatly affected, where the highest number (n = 76) of tree damage, and (n = 21) the entire diameter of trunks were damaged. People of the study area claimed that the black bear causes great forest damage, as well as crop destruction that leads to high economic loss.
... Опасности зимнего периода, оказывающие влияние в основном на лесозаготовительную деятельность и вывозку древесины, изучены гораздо хуже, хотя около 80 % перевозок заготовленного древесного сырья производится по зимникам [Мохирев и др., 2018]. В этом вопросе наибольшую популярность получили исследования таких негативных факторов, как сильные ветры [Nilsson et al., 2004;, метели [Журавлев и др., 2019], неустойчивое состояние зимних лесовозных дорог [Лукашевич, 2013]. ...
... destruction . In total, 110 million (mil) m 3 of timber were lost to storms in Sweden in the twentieth century (Nilsson et al. 2004). However, studies showed that the damage could be reduced by 50% by decisive forest management practices in these conifer forests (Albrecht et al. 2015). ...
Key message
Windstorms have recently caused noteworthy destruction across the Northern forests of Turkey. The intensive forest management practices applied for more than 60+ years may unknowingly have resulted in wind-sensitive forests in the region. After a storm, the forest service salvages the losses, but no further precaution is taken against future storms. To our knowledge, there has not been any research looking into the cumulative effects of environmental factors on storm damage in Turkish forests. Maxent, which is an ecological niche model, might help decision-makers in developing forest management strategies against storms given its ease of use, known successful performance, and flexible variable evaluation approach. This study revealed that management preferences were mainly responsible for forest storm damage in Kastamonu Province, Turkey.
ContextExcessive wind cause serious damages to individual trees and forest stands. When unintentionally coupled with the forest management preferences, catastrophic levels of damage might be unavoidable.AimsThe main objective was to assess the environmental factors contributing to the impact of a strong windstorm that occurred between March 14 and 15, 2013 and resulted in 1.5-million m3 timber losses in the Kastamonu Regional Directorate of Forestry.Methods
Maximum entropy modeling (Maxent) and geographic information systems (GIS) were used to evaluate the factors contributing to the forest damage.ResultsStand type, diameter class, and elevation were the most important variables affecting the level of wind damage. The pure and mixed coniferous stands were the hardest hit when compared with the deciduous stands. The damage increased as the density of forest roads grew.Conclusion
It was concluded that windstorms pose serious threats to Turkish forests. Storm damage risks must therefore be integrated into forest management. In order to better understand the environmental factors contributing to the destructive effects of windstorms in forests, it would be best to focus on the telltale signs pointing the wrong-doing in forest management preferences at larger environmental scale rather than looking for reasons behind the occurrences of scattered small-scale damage.
... Nevertheless, tuning windthrow parameters remained necessary for gustiness, maximum damage rate (which is a parameter to account for the large simulations units, i.e. 2500 km 2 , in OR-CHIDEE versus the small scale at which storm damage occurs) and the relaxation factor for the damage function (R f in Eq. 12 in Chen et al., 2018, which is the parameter that converts the difference between the critical and actual wind speed into a damage rate). To achieve this, Swedish data from 1981 to 2000(Nilsson et al., 2004), a period characterized by the absence of major storms in Sweden, was selected. Tuned parameters reproduced the annual storm damage in Sweden between 1981 to 2000 with a root-mean-square error of 1.3 Mm 3 yr −1 , as well as the observed damage from windstorm Gudrun in 2005 (75 Mm 3 of reported damage versus 77 Mm 3 of simulated damage) ( Chen et al., 2018). ...
Strong winds may uproot and break trees and represent a major natural disturbance for European forests. Wind disturbances have intensified over the last decades globally and are expected to further rise in view of the effects of climate change. Despite the importance of such natural disturbances, there are currently no spatially explicit databases of wind-related impact at a pan-European scale. Here, we present a new database of wind disturbances in European forests (FORWIND). FORWIND is comprised of more than 80 000 spatially delineated areas in Europe that were disturbed by wind in the period 2000–2018 and describes them in a harmonized and consistent geographical vector format. The database includes all major windstorms that occurred over the observational period (e.g. Gudrun, Kyrill, Klaus, Xynthia and Vaia) and represents approximately 30 % of the reported damaging wind events in Europe. Correlation analyses between the areas in FORWIND and land cover changes retrieved from the Landsat-based Global Forest Change dataset and the MODIS Global Disturbance Index corroborate the robustness of FORWIND. Spearman rank coefficients range between 0.27 and 0.48 (p value < 0.05). When recorded forest areas are rescaled based on their damage degree, correlation increases to 0.54. Wind-damaged growing stock volumes reported in national inventories (FORESTORM dataset) are generally higher than analogous metrics provided by FORWIND in combination with satellite-based biomass and country-scale statistics of growing stock volume. The potential of FORWIND is explored for a range of challenging topics and scientific fields, including scaling relations of wind damage, forest vulnerability modelling, remote sensing monitoring of forest disturbance, representation of uprooting and breakage of trees in large-scale land surface models, and hydrogeological risks following wind damage. Overall, FORWIND represents an essential and open-access spatial source that can be used to improve the understanding, detection and prediction of wind disturbances and the consequent impacts on forest ecosystems and the land–atmosphere system. Data sharing is encouraged in order to continuously update and improve FORWIND. The dataset is available at 10.6084/m9.figshare.9555008 (Forzieri et al., 2019).
... Nevertheless, tuning windthrow parameters remained necessary for gustiness, maximum damage rate (which is a parameter to account for the large simulations units, i.e. 2500 km 2 , in OR-CHIDEE versus the small scale at which storm damage occurs) and the relaxation factor for the damage function (R f in Eq. 12 in Chen et al., 2018, which is the parameter that converts the difference between the critical and actual wind speed into a damage rate). To achieve this, Swedish data from 1981 to 2000(Nilsson et al., 2004), a period characterized by the absence of major storms in Sweden, was selected. Tuned parameters reproduced the annual storm damage in Sweden between 1981 to 2000 with a root-mean-square error of 1.3 Mm 3 yr −1 , as well as the observed damage from windstorm Gudrun in 2005 (75 Mm 3 of reported damage versus 77 Mm 3 of simulated damage) ( Chen et al., 2018). ...
Strong winds may uproot and break trees and represent one of the major natural disturbances for European forests. Wind disturbances have intensified over the last decades globally and are expected to further rise in view of the climate change effects. Despite the importance of such natural disturbances, there are currently no spatially-explicit databases of wind-related 45 impact at Pan-European scale. Here, we present a new database of wind disturbances in European forests (FORWIND). FORWIND comprises more than 80,000 spatially delineated areas in Europe that were disturbed by wind in the period 2000-2018, and describes them in a harmonized and consistent geographical vector format. Correlation analyses performed between the areas in FORWIND and land cover changes retrieved from the Landsat-based Global Forest Change dataset and the MODIS Global Disturbance Index corroborate the robustness of FORWIND. Spearman rank coefficients range between 0.27 and 0.48 50 (p-value<0.05). When recorded forest areas are rescaled based on their damage degree, correlation increases to 0.54. Wind-damaged growing stock volumes reported in national inventories (FORESTORM dataset) are generally higher than analogous metrics provided by FORWIND in combination with satellite-based biomass and country-scale statistics of growing stock volume. Overall, FORWIND represents a valuable and open-access spatial source to improve our understanding of the vulnerability of forests to winds and develop large-scale monitoring/modelling of natural disturbances. Data sharing is 55 encouraged in order to continuously update and improve FORWIND. The dataset is available at https://doi.org/10.6084/m9.figshare.9555008 (Forzieri et al., 2019).
... In natural boreal forests, dead wood volumes are large (Esseen et al. 1997;Siitonen 2001) and typically vary between 40-170 m 3 per hectare (Aakala 2010). Much larger volumes can be present after stand-replacing disturbances such as storms (Nilsson et al. 2004), fires (Spies et al. 1988), or bark beetle outbreaks . In managed boreal forests, by contrast, the amount of dead wood is usually more than ten-fold smaller (Siitonen 2001; but see Eräjää et al. 2010). ...
Dead wood profile of a forest is a useful tool for describing forest characteristics and assessing forest disturbance history. Nevertheless, dead wood profiles, including both coarse and fine dead wood, are rare as well as studies on the effect of sampling intensity on the dead wood estimates. In a semi-natural boreal forest, we measured every dead wood item over 2 cm in diameter from 80 study plots. From eight plots, we further recorded dead wood items below 2 cm in diameter. Based on these data we constructed the full dead wood profile, i.e. the overall number of dead wood items and their distribution among different tree species, volumes of different size and decay stage categories. We discovered that while the number of small dead wood items was immense, their number dropped drastically from the diameter below 1 cm to diameters 2-3 cm. Different tree species had notably different abundance-diameter distribution patterns: spruce dead wood comprised mainly of the smallest diameter fractions, whereas aspen dead wood had larger share of large-diameter items. Considering volume, most dead wood was large (>10 cm in diameter), out of which 62% was birch. We also observed that the variation in the dead wood estimates was small for the numerically dominant tree species and smallest diameter categories, but high for the sub-dominant tree species and larger size categories. In conclusion, the more the focus of the dead wood inventory is on rare tree species and large dead wood items, the more comprehensive should the sampling be.
... Ecological studies after such disturbances have therefore focused primarily on plant-community development, tree regeneration, and the re-establishment of closed forest canopies [7][8][9]. Windstorms, however, have also destroyed forests in national parks and reserves across Europe that were developed to conserve the biodiversity of rare habitats, e.g., primeval forests or wetlands, and to encourage tourism and economic and social development in rural areas [5,[10][11][12][13]. Two strong windstorms in 2004 and 2014 destroyed thousands of hectares of spruce forest in the Tatra National Park, Slovakia, both leading to extensive outbreaks of bark beetles [14,15]. ...
Windstorms can often decrease the diversity of native local biota in European forests. The effects of windstorms on the species richness of flora and fauna in coniferous forests of natural reserves are well established, but the effects on biotas in productive deciduous forests have been less well studied. We analyzed the impact of windstorms on the diversity and abundance of soil nematode communities and microbial activity and their relationships with the succession of plant species and basic soil physicochemical properties 12 and 36 months after a windstorm in Fagus sylvatica forests. The relationships were investigated in cleared early-successional forest ecosystems and at undamaged forest sites as a control. The windstorm significantly affected total nematode abundance, number of nematode species, and the diversity and abundance of all nematode functional guilds, but no functional guilds disappeared after the disturbance. The abundance of several nematode taxa but not total nematode abundance was positively correlated with soil-moisture content. Indices of the nematode communities were inconsistent between sites due to their variable ability to identify ecosystem disturbance 12 months after the storm. In contrast, the metabolic activity of various functional groups identified ecosystem disturbance well throughout the study. Positive correlations were identified between the number of plant parasites and soil-moisture content and between carnivore abundance and soil pH. Positive mutual links of some nematode genera (mainly plant parasites) with the distribution of dominant grasses and herbs depended on the habitat. In contrast, microbial activity differed significantly between disturbed and undisturbed sites up to 36 months after the storm, especially soil basal respiration, N mineralization, and microbial biomass. Our results indicated different temporal responses for two groups of soil organisms to the destruction of the tree canopy. Soil nematodes reacted immediately, but changes in the microbial communities were visible much later after the disturbance.
... Whereas climate projections do not provide clear indications of altered frequencies or intensities of storms in Sweden (Kjellström et al. 2014), windthrow increases with wet, mild winters with less soil freezing. Over the last century storm damage has increased in Sweden (Nilsson et al. 2004), largely due to the increased use of spruce monocultures (Schlyter et al. 2006). Because spruce is vulnerable to storm damage (Valinger and Fridman 2011), the increased use of spruce may increase storm damage risks (Blennow et al. 2010), as has occurred in Germany (Griess et al. 2012) and Finland (Suvanto et al. 2016). ...
The choice of tree species used in production forests matters for biodiversity and ecosystem services. In Sweden, damage to young production forests by large browsing herbivores is helping to drive a development where sites traditionally regenerated with Scots pine (Pinus sylvestris) are instead being regenerated with Norway spruce (Picea abies). We provide a condensed synthesis of the available evidence regarding the likely resultant implications for forest biodiversity and ecosystem services from this change in tree species. Apart from some benefits (e.g. reduced stand-level browsing damage), we identified a range of negative outcomes for biodiversity, production, esthetic and recreational values, as well as increased stand vulnerability to storm, frost, and drought damage, and potentially higher risks of pest and pathogen outbreak. Our results are directly relevant to forest owners and policy-makers seeking information regarding the uncertainties, risks, and trade-offs likely to result from changing the tree species in production forests.
... The difference in stand structure (even aged or uneven aged) was the cause of differences in disturbed areas between the Hyrcanian and Camaldoli forest sites. However, other factors can also affect soil disturbance levels, such as wind speed and duration, tree species, and soil depth (Valinger and Pettersson 1996;Nilsson et al. 2004;Zubizarreta-Gerendiain et al. 2012;Coates et al. 2018). ...
One of the main problems in close-to-nature management of high forests is linked to the ecological and economic aspects of salvage logging. This research involved analysing soil disturbance from salvage logging in four mountain forests, managed with close-to-nature silviculture: the Hyrcanian forest (three forest compartments in Iran), using extraction by skidder, and the Camaldoli forest (one parcel in Italy), using extraction by tractor. The point transect method was used for assessing soil disturbance and also included further measurements of ruts’ size and selected physical soil parameters on skid trails after operation. After a windstorm, more than 94% and 17% of the area were undisturbed in the Hyrcanian and Camaldoli forests, respectively. Bulk density, penetration resistance, and pH did not show any significant differences with their average values specifically between disturbed and undisturbed soil after a windstorm. Related only to the effect of salvage logging, more than 80% of the area was undisturbed. The results were significantly lower in terms of the average values of soil variables such as bulk density, penetration resistance, and total porosity in disturbed soil than in undisturbed soil. For all the sites that were studied, bulk density and penetration resistance increased with the increasing number of machines that passes, while total porosity decreased. The results showed significant positive correlations between bulk density and penetration resistance, bulk density and pH value, and total porosity and pH value and significant negative correlations between bulk density and total porosity and penetration resistance and total porosity. The results indicated that the point transect method of assessing soil disturbance provides a rapid assessment of soil conditions for monitoring soil disturbance after salvage logging. Our results also indicated that to reduce impacts to soil during salvage logging, if the volume of windthrow timber is low, salvage logging is not always necessary because of the broad ecological importance as well as the economic aspects of dead wood in forest ecosystems.
... The main result of the study is the development of the GIS database on large-scale fireand wind-induced forest disturbances in the Ural region, occurring in 2000-2014. This is one of the first such studies for the territory of Russia, unlike European countries, which have developed long-term data series on natural forest disturbances more than 10 years ago (Schelhaas et al. 2003;Nilsson et al. 2004). ...
Large-scale wildfires and windstorms are the most important disturbance agents for the Russian boreal forests. The paper presents an assessment of fire-related and wind-induced forest losses in the Ural region of Russia for 2000‒2014. The assessment is based on the use of Landsat images, Global Forest Change dataset (Hansen et al. in Science 342:850–853, 2013. https://doi.org/10.1126/science.1244693) and other space imagery data. The total area of stand-replacement fires and windthrows in the Ural’s forests was estimated at 1.637 million ha, which is 1.56% of the total forest-covered area. The contribution of wildfires and windthrows is 96.4% and 3.6%, respectively. The highest frequency of large-scale wildfires was observed behind the Northern Ural ridge, where the fire scars of 2000‒2014 covered 10–14% of the forested area. The storm-related forest damage is significant only on the western part of the Ural. A few catastrophic wildfires and windthrows (with an area > 5000 ha) make up 35% of the entire damaged area. The number of wildfires, windthrows and their damaged area vary significantly from year to year. For 2000–2014, it is impossible to find a statistically significant trend of the fire- and storm-damaged area. The seasonal maximum of large-scale wildfires and windthrows was observed in July. Also, we identified the statistically significant relationships of fire- and wind-related forest damage with environmental variables. The occurrence of large-scale wildfires is related mainly to the species composition of forests, and also to the altitude, the mean annual precipitation and the population density. The spatial distribution of massive windthrows has a strong correlation with the species composition of forests, the mean annual precipitation and partially with the wind effect parameter.
... Moreover, there are several examples that bark beetles on spruce following wind, fire, drought, snow or ice (Groot et al. 2018) was subsequently more dangerous pest than previous primary agents ( Christiansen & Bakke 1988;Kunca et al. 2011;Nikolov et al. 2014;). Catastrophic bark beetle outbreak after windstorms have occurred in the Czech republic in the Šumava Mountains after windstorms of 1868 and 1870 (Pfeffer & Skuhravy 1995), in Sweden in 1969(Nilsson et al. 2004) or recently in Sweden in 2005(Langström et al. 2009), in Lithuania (Zolubas & Dagilius 2009) or in Far East Russia (Soukhovolsky 2009;Tarasova 2009 (Koreň 2005;, the broken and uprooted trees were not processed completely by the beginning of the growing season 2007. Slovak law on nature conservation prevented that kind of management of damaged wood, so secondary damaging agents, mainly European spruce bark beetle, started to multiply its population abundance (Kunca et al. 2011;Nikolov et al. 2014). ...
Global climate change also influences the forest damaging agents occurrence and thus a forest health. Forest trees that are damaged by agents are in managed forests processed by salvage felling. The amount of an annual salvage felling represents the occurrence of a damaging agents occurrence in a certain year. In 2015, the area of forests in Slovakia reached 2.014 mil. ha. Within the 20 years (from 1998 to 2017), the total felling reached 162.52 mil. m3, out of this 47.99 % were ascribed to a salvage felling. Abiotic agents were the most damaging agents (42.28 mil. m3 of damaged wood), out of it a wind was the most important one. Biotic damaging agents were the second important group (32.165 mil. m3), whereas bark beetles on spruce were the most important. The third group and the less damaging one was anthropogenic agents group (3.555 mil. m3) with an air pollution as the most important damaging agent. There was no statistically significant difference in the volume of processed trees within salvage felling caused by abiotic and biotic damaging agents. However, these two groups caused significantly higher damages than the third group of anthropogenic damaging agents. There were two major wind damages, Alžbeta in 2004 and Žofia in 2014 with damaged wood 5.3 mil. m3 and 5.2 mil. m3, respectively. They occurred in southern, central and northern part of Slovakia. As damaged wood was not processed from strict nature conservation areas, the secondary damaging agents, mostly Ips typographus on Norway spruce reproduced as much that after some years it cumulatively reached or even exceeded damages from those two major windthrows episodes.
... Belated treatment of breaks is unambiguously linked with one of the most serious Ips typographus outbreaks in Šumava (Jelínek 1988;Skuhravý 2002). Similarly, breaks are also mentioned as the cause of Ips typographus outbreaks in other countries, for example in Sweden in 1969 (Nilsson et al. 2004) as well as in and 2007Langström et al. 2009), in Lithuania (Zolubas & Dagilius 2009) and Siberia (Soukhovolsky 2009;Tarasova 2009). The situation was similar also in Slovakia after the Alžběta windstorm in 2004 (Koreň 2005;Kunca 2005;Kunca & Zúbrik 2006). ...
The incidence of salvage felling is a significant indicator of stands‘ health and stability. Health is mainly indicated by biotic and anthropogenic factors, while abiotic effects are primarily an indicator of a stand’s stability. All these factors influence each other and subsequently they can result in salvage felling. For the Czech Republic, there have been relevant data for the period since 1964. Actually, recent data cover approximately 70% of the Czech Republic´s area in the twenty-year period assessed in this text. During this period, the volume of salvage felling amounted to 89.2 million m3 which represents 28.4% of total felling in this period. The largest share is caused by abiotic effects (18.6%), next by biotic agents (9.6%) and anthropogenic are only responsible for 0.2%. In the last two years, the volume of salvage felling caused by biotic agents was higher than the volume of salvage felling caused by abiotic and anthropogenic agents for the first time. In terms of biotic agents, almost the whole volume is represented by bark beetle wood as a result of spruce stands infestation by the European spruce bark beetle – Ips typographus (L.) and double-spined bark beetle – Ips duplicatus (Sahl.), and to a small extent also by other species of bark beetles on spruce, pine and occasionally other wood tree species. In the last three years, mainly the incidence of the Ips typographus L., has concentrated in North Moravia and Silesia. Currently, it is also spreading in South Moravia and Bohemia and in districts along the state borders with Austria and Germany, with the most serious situation in this region being the one in the Bohemian-Moravian Highlands.
... Windthrows are natural hazards and a significant body of literature has been published on this particular issue (Ulanova, 2000;Klaus et al., 2011;Nilsson et al., 2004;Schliemann & Bockheim, 2011;Boon, 2012). Nowadays, windthrows are included into the large concept of natural disturbances (Popa, 2008), along with wildfires, droughts, and insects' attacks. ...
Aim of study: To better estimate the annual allowable cut reserve (AACR), taking into consideration the endemic windthrows (EW), we combined a series of existing algorithms into a coherent methodology to use the data available at district level, without any additional fieldworks.
Area of study: The algorithm was tested on the EW occurred in the last 20 years in Brosteni FD (Eastern Carpathians, Romania) that covers 21,013 ha and we found that every year from an AAC of 37,000 m3 no more than 2,700 m3 shall be spared for EW that might occur next year.
Material and methods: We considered three EW enabling factors (stand slenderness, location on pits and mounds, and the vicinity of canopy gap) and three contingency tables of the EW produced between 1999 and 2008, one for each 40-year age group. Then we calculated a Bayesian model for all six permutations of enabling factors, each of them being tested on the data referring to 2008-2017 period
Results: Plugging the posterior EW likelihoods into a Markov chains (MC) model, we produced a formula that enables a better estimation of the optimal AACR that could be replaced with salvage cuttings every next year. Other options of using the EW likelihoods are also presented at length, such as the type of age-class structure that requires no AACR, that is a “U” shape age structure, as well as a rough assessment of the additional demand for seedlings needed to re-plant the stands affected by EW. The relatively short period of time the input data refer to, which is ten years, equals the time window of the forest planning and this parity allows a ten-year forecast period, enough for modeling the stationary age-structure of even-aged forests.
Research highlights: A new model for optimizing the annual allowable cut (AAC) in even-age forests in the context of endemic windthrows (EW) scenario has been developed and evaluated.
Keywords: Bayes’ rule, forest management planning, endemic windthrows.
... Ips typographus is the most destructive insect pest of mature Norway spruce [Picea abies (L.) Karst] in Europe, and may kill millions of trees during outbreaks (Seidl et al., 2011;Marini et al., 2017), which may be triggered by storm disturbances, warm summers or precipitation deficits (Marini et al., 2013(Marini et al., , 2017. Storm is the most frequent disturbance factor in Swedish forests, felling large volumes of trees, and Norway spruce is an especially vulnerable tree species (Nilsson et al., 2004;Mason & Valinger, 2013). Thus, major storms leave large numbers of storm-felled Norway spruce trees with weak defences, thereby creating abundant ideal breeding material for I. typographus, in which reproductive success is high (Komonen et al., 2011). ...
The North American lodgepole pine Pinus contorta has been planted on 660 000 ha in Sweden.
We compared the performance of Ips typographus and Pityogenes chalcographus in storm‐felled and standing pheromone‐baited trees of the historical host species Norway spruce ( Picea abies ) and lodgepole pine.
In the first summer after a storm, I. typographus colonized 0.2% and P. chalcographus colonized 2.4% of the storm‐felled lodgepole pines compared with 31% and 25%, respectively, of the storm‐felled Norway spruces. In the second summer 1.6% and 41.5% of the lodgepole pines were colonized by I. typographus and P. chalcographus , respectively. The reproductive success of I. typographus was five‐fold higher in Norway spruce than in lodgepole pine. Other species colonizing lodgepole pine were Ips duplicatus , Orthotomicus proximus , Orthotomicus laricis , Monochamus sutor and Pissodes pini .
The male attack densities of both bark beetle species required to overcome defences of standing pheromone‐baited trees were much higher in lodgepole pine than in Norway spruce. The reproductive success of I. typographus and P. chalcographus was approximately five‐ and 14‐fold higher, respectively, in Norway spruce than in lodgepole pine.
Larvae of the most important groups of bark beetle enemies were present in both storm‐felled and standing pheromone‐baited lodgepole pines colonized by I. typographus and P. chalcographus . In the standing trees, the densities of enemy larvae were lower in lodgepole pine than in Norway spruce, whereas the opposite was true for storm‐felled trees.
... Hilker et al. [51] used a fusion model incorporating Landsat and MODIS data for detecting forest disturbances with high temporal and spatial resolution. As different types of forest disturbances often exhibit a distinct seasonality, such as windthrows [53,54], insect outbreaks [55,56] or fires [57,58], information on the timing of disturbance events within a year may potentially help to infer the underlying disturbance agent [13]. ...
The attribution of forest disturbances to disturbance agents is a critical challenge for remote sensing-based forest monitoring, promising important insights into drivers and impacts of forest disturbances. Previous studies have used spectral-temporal metrics derived from annual Landsat time series to identify disturbance agents. Here, we extend this approach to new predictors derived from intra-annual time series and test it at three sites in Central Europe, including managed and protected forests. The two newly tested predictors are: (1) intra-annual timing of disturbance events and (2) temporal proximity to windstorms based on prior knowledge. We estimated the intra-annual timing of disturbances using a breakpoint detection algorithm and all available Landsat observations between 1984 and 2016. Using spectral, temporal, and topography-related metrics, we then mapped four disturbance classes: windthrow, cleared windthrow, bark beetles, and other harvest. Disturbance agents were identified with overall accuracies of 76–86%. Temporal proximity to storm events was among the most important predictors, while intra-annual timing itself was less important. Moreover, elevation information was very effective for discriminating disturbance agents. Our results demonstrate the potential of incorporating dense, intra-annual Landsat time series information and prior knowledge of disturbance events for monitoring forest ecosystem change at the disturbance agent level.
... Windstorms are among the most significant types of disturbance event affecting woodlands in many parts of the world (Webb 1999;Lugo 2008;Mitchell 2013). Because of this special threat, they are often analysed with respect to their effects on forests (Brázdil 1998;Nekovář and Valter 1998;Schelhaas et al. 2003;Nilsson et al. 2004;Falťan et al. 2009;Gardiner et al. 2010;Usbeck et al. 2010;Brůna et al. 2013;Usbeck 2014). ...
One of the most disastrous windstorms to take place over the Czech Lands occurred on the night of 26/27 October 1870. It is here analysed through the use of documentary data (narrative sources, newspapers, forestry journals, printed documents) and systematic meteorological observations (wind force and direction). ombining this evidence with information derived from an atmospheric reanalysis dataset allows the severity of the windstorm to be attributed to the passage of a cold front, a frontal system associated with a secondary low in a typically storm-prone synoptic environment. Its social impacts were characterised by great material damage, particularly to buildings and other structures, trees and forests. These are recorded not only for 174 places around the countryside and lesser settlements of the Czech Lands, but also for 28 city quarters in Prague, the capital city. The windstorm occurred in the night hours, so only a few people were killed or injured. However, the 1870 windstorm totally devastated many forested areas of the Šumava Mts. in south-west Bohemia. Damage to forests in other parts of the Czech Lands was also severe, but difficult to quantify exactly for lack of high-resolution spatial data. Because this windstorm followed only shortly upon a previous similarly disastrous wind event on 7 December 1868, the enormous quantity of windthrown wood in forests, which simply could not be fast-processed, contributed significantly to a subsequent bark-beetle infestation calamity in the 1870s. In certain forest stands, imprints of these aggregate effects appear to this day. The central-European scale of 1870 windstorm is also well documented by meteorological and documentary data from Germany, Austria and Slovakia.
... It is important to note that such figures do not take into account the potential for exceptionally strong wind events to damage large areas of forest land, and thus open up large areas for regeneration. Over the last century, Götaland has experienced greater forest losses to such events than northern Sweden (Nilsson et al., 2004). In January of 2005 a storm (Gudrun) fell almost 75 million cubic meter of timber, amounting to almost a year's harvest for the entire country. ...
This article was submitted without an abstract, please refer to the full-text PDF file.
... Over the last few decades, windthrow disturbances have increased in frequency and severity in European coniferous forests (Nilsson et al., 2004;Seidl et al., 2011). The abundance of windthrown Norway spruce trees triggers population growth of the bark beetle, Ips typographus L. (Marini et al., 2013;Økland and Berryman, 2004;Wermelinger, 2004), as Norway spruce is the bark beetle's main host (Sauvard, 2004). ...
Natural disturbances such as windthrow and bark beetle Ips typographus L. outbreak often affect protected areas with non-intervention type of management located in close proximity to managed forest stands. This raises concerns about the migration of the beetle outbreak from non-intervention zones to adjacent managed forests. In this study we analyzed the spatiotemporal dynamics of large-scale disturbances by intervention and non-intervention type of management in the Tatra mountains (Central Europe). We collected a time series of Landsat images from 2003 to 2014, and applied maximum likelihood classification to map the extent of forest, windthrow, clear-cuts, beetle outbreak and fire. Our classified maps achieved high overall accuracies: 0.93 ± 0.03 ⩽ OA ⩽ 0.96 ± 0.03. The extent of forest declined over the study period. We found higher rate of beetle induced tree mortality in non-intervention versus intervention zone. Within two growing seasons after the windthrow, beetle infestation occurred in close proximity to uncleared windthrow (<∼250 m), which suggest the positive effect of salvage logging (removal of windthrown trees) on lowering the risk of beetle outbreak. The two times higher sum of disturbances in intervention then in non-intervention zone indicated the limited impact of sanitation felling (removal of standing beetle infested trees) to reduce beetle population. However, sanitation felling highly contributed to the decline of the forest cover. Overall, our results document the dynamics of windthrow, bark beetle and clear-cuts by type of management, and limited impact of logging activities in reducing beetle outbreak in neighboring areas with intervention and non-intervention type of management.
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... Forested areas started to come under national administration around the same time all over Europe (e.g. 1848 in the Czech Lands for Bohemia and a year later for Moravia and Silesia - Nožička, 1957), enabling the assessment of windstorm impacts on forestry for both historical and recent periods (Nilsson et al., 2004;Gardiner et al., 2010;Usbeck et al., 2010). In addition to inappropriate forest management measures with respect to species mix, stand height and age, certain hydrometeorological effects such as wet, unfrozen soils have been found to facilitate the uprooting of trees (e.g. ...
An extreme windstorm that took place on 7 December 1868 in the Czech Lands is analysed by means of rich documentary evidence from narrative sources, damage records, forestry journals and newspapers. Early meteorological measurements and a numerical atmospheric reanalysis support the documentary reconstruction. The windstorm reached hurricane-force over the Czech Lands between 0900 and 1600 of local mean time and was related to the passage of a cold front. The high winds, achieving hurricane-force, led to loss of human lives and many other casualties, as well as to severe damage to buildings and other structures. In particular, the documentary sources facilitate a quantitative reconstruction of the massive windthrow that occurred in forested areas across the Czech Lands, where the windstorm damaged at least 8 million m3 of timber, which is arguably more than has been lost to any single similar event since. Reasons for the extreme windthrow, apart from wind forces and destabilization arising from wet and thawed soils, were found in increased vulnerability arising out of old, dense and mono-species conifer stands and inadequate clear-cutting and thinning measures. For the Czech Lands, this event was the most damaging windstorm in the 19th century. Moreover, damage reports are found from the British Isles, the Netherlands, Belgium and Germany to Austria, the Czech Lands and Poland, documenting its disastrous effects on a (sub-)continental scale.
In Central Europe, the focus of forest restoration is less on increasing the forest area than on increasing or improving the multifunctionality and ecosystem services of existing forests, particularly through an appropriate and sustainable silvicultural management. Forest history, forest ecology and vegetation as well as the ecosystem services of Central European forests are outlined. Specific strategies and measures of forest restoration are addressed. A focus is put on the conversion of anthropogenic coniferous forests into near-natural mixed broad-leaved forests. As a case study, the successful forest restoration in the north-western German lignite mining area after approximately 80 years is documented.
Storms constitute one of the major natural disturbances in Sweden and its associated damages appear to be in an upward trend during the last 35 years in Europe. In addition, storm damages are expected to increase in the future due to the shortening of the soil frost period during the winter caused by climate change. Here we present a new optimization model to be used in forest planning for decreasing the wind exposure for storms over time through the minimization of vulnerable edges between neighbouring stands in a forest property. Three different cases were investigated where height differences of 5, 10 and 15 m between neighbouring stands were used to identify vulnerable edges in the property. The model, which accounts for the higher sensitivity of spruce compared to other tree species, was formulated as a mixed integer programming problem and solved using a branch and bound algorithm in a case study for a forest property in southern Sweden. In the case study, we investigated the trade-off between minimizing the length of vulnerable stand edges and the net present value from wood production. Our results show that it is possible to decrease vulnerable edge length with relatively moderate declines in the maximum achievable net present value, resulting in a clustering of dominant heights of neighbouring stands. Larger decreases in vulnerable edge length led to larger decreases in net present value, and an increased area proportion of forest older than 80 years. This model can easily be adapted to other planning problems in which edge effects are important.
The study analyzes the major adverse factors that caused destruction of forest stands in Novgorod region over the past 10 years based on the data on monitoring the state of forest ecosystems. Adverse effects such as weather conditions, fires, forest diseases, and insect forest pests were considered. The crucial reason of forest stand mortality in the region over the period under study was revealed. The features and patterns of the mortality of forest stands were studied with regard to their taxation characteristics and confinement to the natural landscapes of the region.
Tree planting has been widely touted as an inexpensive way to meet multiple international environmental goals for mitigating climate change, reversing landscape degradation and restoring biodiversity restoration. The Bonn Challenge and New York Declaration on Forests, motivated by widespread deforestation and forest degradation, call for restoring 350 million ha by 2030 by relying on forest landscape restoration (FLR) processes. Because the 173 million ha commitments made by 63 nations, regions and companies are not legally binding, expectations of what FLR means lacks consensus. The frequent disconnect between top-level aspirations and on-the-ground implementation results in limited data on FLR activities. Additionally, some countries have made landscape-scale restoration outside of the Bonn Challenge. We compared and contrasted the theory and practice of FLR and compiled information from databases of projects and initiatives and case studies. We present the main FLR initiatives happening across regional groups; in many regions, the potential need/ opportunity for forest restoration exceeds the FLR activities underway. Multiple objectives can be met by manipulating vegetation (increasing structural complexity, changing species composition and restoring natural disturbances). Livelihood interventions are context-specific but include collecting or raising non-timber forest products, employment and community forests; other interventions address tenure and governance.
Severe winds are among the main causes of disturbances in boreal and temperate forests. Here, we present a new geographic information system (GIS) database of stand-replacing windthrow events in the forest zone of European Russia (ER) for the 1986–2017 period. The delineation of windthrow areas was based on the full Landsat archive and two Landsat-derived products on forest cover change, namely the Global Forest Change and the Eastern Europe's forest cover change datasets. Subsequent verification and analysis of each windthrow was carried out manually to determine the type of related storm event, its date or date range, and geometrical characteristics. The database contains 102 747 elementary areas of damaged forest that were combined into 700 windthrow events caused by 486 convective or non-convective storms. The database includes stand-replacing windthrows only with an area > 0.05 and > 0.25 km2 for the events caused by tornadoes and other storms, respectively. Additional information such as weather station reports and event descriptions from media sources is also provided. The total area of stand-replacing windthrows amounts to 2966 km2, which is 0.19 % of the forested area of the study region. Convective windstorms contribute 82.5 % to the total wind-damaged area, while tornadoes and non-convective windstorms are responsible for 12.9 % and 4.6 % of this area, respectively. Most of the windthrow events in ER happened in summer, which is in contrast to Western and Central Europe, where they mainly occur in autumn and winter. Due to several data and method limitations, the compiled database is spatially and temporally inhomogeneous and hence incomplete. Despite this incompleteness, the presented database provides a valuable source of spatial and temporal information on windthrow in ER and can be used by both science and management. The database is available at 10.6084/m9.figshare.12073278.v6 (Shikhov et al., 2020).
Streamside forests are preserved from clear-cut logging in production forests and protected with uncut buffer strips in many countries. However, buffer strips often remain narrow due to economic reasons and, therefore, provide weak protection against adverse edge effects of clear-cuts and are vulnerable to windthrow. Selective logging of buffer strips is sometimes allowed to reduce their costs, but the decreased tree density may expose the buffer to higher occurrence of windthrow. We used a replicated two-factor experiment to assess the effects of buffer width (15 m or 30 m) and selective logging (0% or 30% of the basal area removed) on the risk of windthrow in boreal streamside forests in Finland. We examined the windthrown trees 12 years after experimental logging at 29 sites and at seven unlogged control sites. In addition, we studied the influence of topography and the extent of clear-cut logging in the surrounding forests on windthrow risk. The proportion of windthrown spruces at sites with 15 m buffer strips was, on the average, six times higher than at control sites and 2.5 times higher than at sites with 30 m buffer strips. In contrast, the proportion of windthrown spruces did not differ between sites with 30 m buffer strips and control sites. Selective logging did not increase the risk of windthrow strongly. However, sites with selectively logged 30 m buffers were slightly more prone to windthrow than control sites. The proportion of windthrown trees tended to increase with the extent of the adjacent clear-cut areas on both sides of the stream. We conclude that a 15 m buffer strip is not wide enough to protect streamside forests from substantial windthrow, while a 30 m buffer strip is sufficient in most cases. Selective logging of 30 m buffers may be undertaken at sites that are not under a high risk of windthrow. If selective logging enables a wider buffer strip, it may be a better option for protecting the streamside habitat from substantial windthrow than leaving a narrow buffer strip. Moreover, clear-cut harvesting on both sides of the stream should be avoided if the aim is to prevent excessive windthrow.
The demographic change is on rise across the world with globalization. Urbanization is unfolding along the spatial distribution of each nation’s territory. Their interlinkange with geophysical and climatic hazards and remedies to be offered for their adverse impact would require knowledge of geophysical conditions modulating the urban growth for appropriate mitigations and adaptative measures. This chapter attempts to understand the urbanization pattern in different geographical setups and its vulnerability with changing climate. It dwells upon the extent of new hazard, risk and vulnerabilities arising out of geophysical condions of new habitats and their mutation with changing climatic conditions and tries to underline the crucial elements for policy makers to get them factored in their prospective urban plan.
Abstract. Severe winds are among the main causes of natural disturbances in boreal and temperate forests. Here, we present a new GIS database of stand-replacing windthrows in the forest zone of the European Russia (ER) for the 1986–2017 period. Delineation of windthrows was based on the full archive of Landsat images and two Landsat-derived products on forest cover change, namely the Global Forest Change and the Eastern’ Europe Forest Cover Change datasets. Subsequent verification and analysis of each windthrow was carried out to determine a type of related storm event, its date or date range, and geometrical characteristics. The database contains 102 747 elementary areas of damaged forest that were combined into 700 windthrows caused by 486 convective or non-convective storm events. The database includes stand-replacing windthrows only, which an area > 5 ha and > 25 ha for events caused by tornadoes and other storms, respectively. Additional information contained weather station reports and event description from media sources is also provided. The total area of windthrows amounts to 2966 km2, that is 0.19 % of the forested area of the study region. Convective windstorms contribute 82.5 % to total wind-damaged area, while tornadoes and non-convective windstorms are responsible for 12.9 % and 4.6 % of this area, respectively. Most of windthrows in the ER happen in to summer that is in contrast to Western and Central Europe, where windthrows mainly occur in autumn and winter. The compiled database provides a valuable source of spatial and temporal information on windthrows in the ER and can be successfully used both in forest science and severe storm studies. The database is available at https://doi.org/10.6084/m9.figshare.12073278.v3 (Shikhov et al., 2020).
A study of carabid assemblages (Coleoptera, Carabidae) was performed in pine stands disturbed by windthrow (Lipusz Forest, North Poland) in 2018, i.e. one year after the disturbance, in five treatments representing different classes of disturbance severity: least disturbed stands (canopy cover of 60–80%), moderately disturbed stands (canopy cover of 20–40%) and severely disturbed stands (canopy cover 0%). Moderately and severely disturbed stands were further subdivided into those with tree crowns lying on the ground and those without, or rather located between broken crowns. Based on the abundance and rarefied number of carabid species, the data did not confirm the hypothesis of higher abundance and species number in assemblages inhabiting the lying tree crowns compared with open windthrown stands without tree crowns. However, results based on carabid ecological traits confirmed the hypothesis of a higher contribution of late-successional species in assemblages under broken tree crowns than in assemblages living between such crowns. This association became stronger with the increasing severity of the windthrow disturbance. These results provide a rationale for leaving at least some lying tree crowns in windthrown stands so that the forest fauna can find refuge under the crowns.
Alongside fires, windthrows are among the strongest forest disturbances, which is why research on the regeneration of windthrown forests is so important for silviculture. While there have been many studies devoted to the regeneration of windthrown boreal spruce forests, few have dealt with the regeneration of Scots pine forests in the temperate zone.
In Pisz Forest (northern Poland), the State Forests administration left 475.6 ha of pine stands disturbed by windthrow for research on spontaneous ecosystem recovery, leaving all broken trees untouched. For the 11-year study (beginning in 2008, six years after the windthrow, when saplings became more abundant), 10 × 10 m research plots were established in pine stands with different classes of severity of windthrow disturbance: severely disturbed stands (canopy cover up to 30%), moderately disturbed stands (canopy cover of 40–60%) and the least disturbed stands (canopy cover of 70–90%). Each year all saplings on the plots were recorded, with measurements of their height, diameter at breast height, and changes in the percentage cover of forest floor vegetation and its species composition. Selected environmental variables were measured as well. Density of pine saplings in the severely disturbed stands was lower than in the moderately and least disturbed stands, while the density of birch saplings was higher in the moderately disturbed stands than in the least disturbed stands. Moss P. schreberi particularly favored spontaneous regeneration of pine saplings, while the nitrophilous grass D. flexuosa, overgrowing entire surfaces, impeded it. Soil cover by a litter layer alone also significantly hampered the emergence of tree saplings. An elevated content of nitrogen in the soil was conducive to rapid coverage of the area by D. flexuosa, while limiting cover by moss P. schreberi. Moss P. schreberi and shrubs V. vitis-idaea preferred soil with a high respiration
rate, while grass D. flexuosa avoided it. Two directions of spontaneous regeneration of windthrown stands were shown, depending on cover by grass or mosses and on the initial content of nitrogen in the soil, which provided the basis for indicating two different forest management strategies in windthrown pine forests.
The paper presents a long-term analysis of fire-related and storm-induced forest disturbances in the northeast European Russia for 1985–2016. The forest disturbances are identified with the use of Landsat images, Global Forest Change data (for 2000–2014) and Eastern’Europe Forest Cover Change data (for 1985–2000). We created the database which contains the data on forest disturbances (burned areas and windthrows) with a total area of 572 thousand ha; 82.4 % of them are burned areas, and the remaining 17,6 % include storm-, tornado- and snow-induced forest damage. The comparison of the identified burned areas with official forest fire data for Komi Republic (for 1996–2016) shows their high degree of coincidence. In 1985–2016, more than 5 % of forest-covered areas were damaged by wildfires in the northwestern and central parts of Komi Republic, and also in the northwest of Perm Krai. Storm-induced forest damage was the most significant in the western part of Kirov region, in the northeast of Perm Krai and southeast of Komi republic. It is shown that the fire-related and storm-induced forest damage increases in the last 30 years. However, the linear trends are statistically insignificant. The estimated trends of forest damaged areas differ from previously published estimates for the entire European Russia. These differences may be related to our more detailed analysis of Landsat images for 1985–1999, because we discovered many previously unknown burned areas and windthrows. Also, we estimated the influence of weather condition of summer season on fire-damaged area based on the data of 15 weather stations. The number of days with maximum temperature higher than +25 and +30 °C, and also the hydrothermal coefficient, averaged for June and July, have the strongest correlation with fire-related forest damage. © 2018 Space Research Institute of the Russian Academy of Sciences. All Rights Reserved.
The pine shoot beetle, Tomicus piniperda (L.), is considered one of the most destructive pests of Scots pine, Pinus sylvestris (L.), in Europe. At high population densities, its feeding in the shoots of living pine trees may lead to substantial shoot and subsequent growth losses. After a storm‐felling in southern Sweden in January 2005, there were high amounts of breeding material and a subsequent risk for bark beetle outbreaks. To study the beetle's reproductive success, population levels and risks for growth losses, we analysed bark samples of colonized trees, and counted fallen pine shoots. During the first season after the storm‐felling, the pine shoot beetle population level was low. However, due to high reproductive success beetle numbers markedly increased in the second season, and there were high rates of successful colonization of available host material in following years. Shoot damage levels concomitantly rose in 2005–2006, then declined in 2007 and 2008. However, the accumulated shoot losses do not indicate any subsequent growth losses, as the recorded shoot damage levels were below those earlier seen in connection with growth reductions in damaged pine stands.
A windthrow disturbance alters the functioning and structure of a forest ecosystem and causes substantial economic losses.
A 10-year pitfall study of carabid assemblages (Coleoptera, Carabidae) was carried out in pine stands disturbed by windthrow (Pisz Forest, North Poland) in the first year after the disturbance, with different classes of severity: severely disturbed stands (canopy cover up to 30%), moderately disturbed stands (canopy cover of 40–60%) and least disturbed stands (canopy cover of 70–90%).
Based on the number of carabid species and their ecological traits, I confirmed the hypothesis that the amplitude of changes in carabid assemblages inhabiting severely and moderately disturbed stands would be greater than in the least disturbed stands. Variation in carabid assemblages was also linked to soil pH and to carbon and nitrogen content in the soil.
The study confirmed my hypothesis regarding the delayed replacement of late successional carabid fauna by early successional fauna, which was linked to the broken pines lying on the soil, allowing late successional fauna to survive in the first few years after the windthrow.
The principal response curve analysis identified three phases of post-disturbance succession in carabid assemblages: (i) slight changes in the number of species and their ecological traits, lasting for 4 years; (ii) ‘rapid’ changes, lasting for 3 years, involving an increase in the number of species and rapid replacement of late successional carabid fauna by early successional fauna; and (iii) the slow recovery of late carabid successional fauna.
Using reports of forest losses caused directly by large scale windstorms (or primary damage, PD) from the European forest institute database (comprising 276 PD reports from 1951–2010), total growing stock (TGS) statistics of European forests and the daily North Atlantic Oscillation (NAO) index, we identify a statistically significant change in storm intensity in Western, Central and Northern Europe (17 countries). Using the validated set of storms, we found that the year 1990 represents a change-point at which the average intensity of the most destructive storms indicated by PD/TGS > 0.08% increased by more than a factor of three. A likelihood ratio test provides strong evidence that the change-point represents a real shift in the statistical behaviour of the time series. All but one of the seven catastrophic storms (PD/TGS > 0.2%) occurred since 1990. Additionally, we detected a related decrease in September–November PD/TGS and an increase in December–February PD/TGS. Our analyses point to the possibility that the impact of climate change on the North Atlantic storms hitting Europe has started during the last two and half decades.
Within the WASA project (von Storch et al. 1998; Bull Am Meterol Soc 79(5):741-760) an extensive data set containing station pressure values was used to calculate geostrophic winds (Alexandersson et al. 1998; Global Atmos Ocean Syst 6:97-120). Geostrophic winds were analysed in terms of percentiles to give a measure of long-term variations in synoptic-scale storminess. In this paper an update to 1998 is presented. In the Scandinavia, Finland and Baltic Sea area the most recent years, especially the cold and calm year 1996, seem to have brought an end to the stormy period centred on 1990. In the more westerly British Isles, North Sea and Norwegian Sea area, storminess is still at high levels compared with the less intense period between 1930 and 1980. The long-term increasing trend in NW Europe storminess that started in the 1960s seems to have been broken.
Two very strong storms made some important damages in France, in December 1999. The meteorological stations compared the mean wind speeds and maximum gust speeds recorded by the French meteorological office to previous observations. A new map of 50 years return period mean wind speed is proposed.
A 240 yr run of the ECHAM4/OPYC3 coupled ocean-atmosphere model with transient greenhouse gas (GHG) forcing according to the IPCC IS92a scenario is examined with respect to simulated changes in boreal winter cyclone activity and 10 m wind speeds over Europe, the North Atlantic and Eastern North America. It is found that simulated cyclone activity undergoes a pronounced north- and eastward shift over Europe and the Northeast Atlantic. This shift is accompanied by a decrease in the number of weak cyclones and an increase in deep cyclones (with core pressures below 970 hPa) in this area. The cyclone signal corresponds to the changes in storm track activity and upper-tropospheric baroclinicity. Increases of mean wind speeds and of wind speed extremes are identified over Northern Europe and parts of the East Atlantic. The wind signal is due to an increase in wind speed variability and an intensification of the westerly mean current connected with an enhanced mean pressure gradient. It is shown that the rising number of extreme wind events in the GHG simulation is connected to the augmented occurrence of deep cyclones over Northern Europe and the adjacent ocean areas. There are also strong wind speed increases over Hudson Bay and the Greenland Sea. They are restricted to the planetary boundary layer and appear to be connected to the reduction in winter mean sea-ice cover, which leads to locally decreased static stability and-over the Greenland Sea-also to a reduction in surface roughness.
In a network of permanent observation plots in Switzerland,the storm Lothar uprooted 18.7% of Fagussylvaticaand 14.8% of Picea abies. The percentage of uprootingwas significantly inversely correlated with actual soil basesaturation (NH4Cl-extract). At a base saturation of40% (calculated as an average over 0–40cm depth) uprootingwas increased by a factor of 4.8 in beech and by a factor of3.6 in Norway spruce compared to less acidic soils. In beech,the percentage of uprooted trees was also significantlycorrelated with nitrogen concentration in the leaves(positively) and with coarse pore volume in the soil(negatively). There was neither a relation with seasonalozone dose nor a relation with crown transparency, stemdiameter, crown size, slenderness, social position andposition within the stand. The results suggest thatanthropogenic stress factors play an important role in theextent of the Lothar damages in Switzerland.
The present article portrays root growth and root system development with special reference to Picea abies. Root phenology and ontogeny are depicted, and the biological responses of the roots to adverse growing conditions appraised. Norway spruce is regarded as a species which is able to grow under a wide range of soil physical and chemical conditions, provided sufficient soil aeration is guaranteed. The root system of spruce is however sensitive to any dislocation of its primary taproot. Nursery handling and planting damage often affect the root system development of the young tree. Soil acidity and Al-toxicity represent other significant restraints to root growth of spruce. Rooting patterns and mycorrhizal communities are influenced by atmospheric deposition of nitrogen and acidity. Root system spread is closely related to the tree’s competitive status in the forest stand and responds to forest management practices. The preference of Norway spruce roots for humus-rich soil horizons and patches is repeatedly reported. Though, a general characterisation of P. abies as a primary ‘surface-rooter’ has been disproved. Different structures and functions of long and short roots can be identified. Periodic shedding of small and fibrous root structures is a natural phenomenon and is influenced by ambient (i.e. climatic) conditions. Nonetheless, adverse growing conditions result in an increased frequency of adventitious root formation. Permanent root system damage will occur when such root replacement strategies fail. The resulting occurrence of root derangement points and the loss of ramification orders, advances from the fine- to the coarse-root structures. The result is an irregular arrangement of the structural root system, with increasing frequency of damaged roots and disturbance of the root system symmetry. Damaged coarse roots are characterised by discolouration following decay. A damage class scheme for Norway spruce that depicts general stages of root system vitality and decay is provided. The work illustrates that root parameters are good indicators of the sustainability of forest sites.
Storms occasionally bring havoc to Northwest Europe. At present, a single storm may cause damage of up to 7 billion U.S.$, of which a substantial part is insured. One scenario of climate change indicates that storm intensity in Northwest Europe could increase by 1-9% because of the doubling of CO2 concentrations in the atmosphere. A geographic-explicit, statistical model, based on recent storms and storm damage data for the Netherlands, shows that an increase of 2% in wind intensity by the year 2015 could lead to a 50% increase in storm damage to houses and businesses. Only 20% of the increase is due to population and economic growth. A 6% increase could even triple the damage. A simpler model - based on national average data and combined with a stochastic storm generator - shows that the average annual damage could increase by 80% with a 2% increase in wind intensity. A 6% wind intensity increase could lead to an average annual damage increase of 500%. The damage in Northwest Europe is about a factor 6 higher than the damage in the Netherlands. Little potential seems to exist for reducing the vulnerability to storms in the Netherlands. More attention should be given to planning at the government level for disaster relief and to the development of coping strategies.
Storms occasionally bring havoc to Northwest Europe. At present, a single storm may cause damage of up to 7 billion U.S.$, of which a substantial part is insured. One scenario of climate change indicates that storm intensity in Northwest Europe could increase by 1–9 % because of the doubling of CO2 concentrations in the atmosphere. A geographic-explicit, statistical model, based on recent storms and storm damage data for the Netherlands, shows that an increase of 2 % in wind intensity by the year 2015 could lead to a 50 % increase in storm damage to houses and businesses. Only 20 % of the increase is due to population and economic growth. A 6 % increase could even triple the damage. A simpler model – based on national average data and combined with a stochastic storm generator – shows that the average annual damage could increase by 80 % with a 2 % increase in wind intensity. A 6 % wind intensity increase could lead to an average annual damage increase of 500%. The damage in Northwest Europe is about a factor 6 higher than the damage in the Netherlands. Little potential seems to exist for reducing the vulnerability to storms in the Netherlands. More attention should be given to planning at the government level for disaster relief and to the development of coping strategies. 1.
We describe the construction of a 10′ latitude/longitude data set of mean monthly surface climate over global land areas, excluding Antarctica. The climatology includes 8 climate elements-precipitation, wet-day frequency, temperature, temperature, diurnal temperature range, relative humidity, sunshine duration, ground frost frequency and windspeed-and was interpolated from a data set of station means for the period centred on 1961 to 1990. Precipitation was first defined in terms of the parameters of the Gamma distribution, enabling the calculation of monthly precipitation at any given return period. The data are compared to an earlier data set at 0.5° latitude/longitude resolution and show added value over most regions. The data will have many applications in applied climatology, biogeochemical modelling, hydrology and agricultural meteorology and are available through the International Water Management Institute World Water and Climate Atlas (http://www.iwmi.org) and the Climatic Research Unit (http://www.cru.uea.ac.uk).
Fine root distribution and turnover were investigated in ca. 40-year-old pure Norway spruce (Picea abies Karst.) stands in Germany, growing on four sites that differed in soil acidity (Ebergötzen < Barbis < Fichtelgebirge = Harz). The density of fine root biomass and necromass in different soil horizons differed among the sites. At one of the most acidic sites (Harz), fine root density in the humus layer was more than twice that at the least acidic site (Ebergötzen). At the two most acidic sites, Fichtelgebirge and Harz, the ratio of biomass to necromass was significantly lower than at Ebergötzen and Barbis, particularly in the subsoil layer. In each stand, clear vertical gradients in fine root length density and root tip density were observed. Most of the roots and the root tips were in the humus layer and in the first mineral soil horizon (0-10 cm). There was a significantly different decrease in specific root length (cm gDM (-1)) and specific root tip density (root tips gDM (-1)) in the more acidified stands Fichtelgebirge and Harz compared with Ebergötzen and Barbis. Fine root production estimated by ingrowth cores and a net method was approximately twice as high in the more acidic stands Fichtelgebirge and Harz compared with Ebergötzen and Barbis. Rates of living fine root biomass turnover were higher at the Fichtelgebirge and Harz sites than at the Ebergötzen site. Rates of necromass turnover were similar at all sites. The results suggest that the accumulation of necromass was not due to a slower disappearance at the more acid sites, but to earlier root death. Roots contributed 46% to root + needle litter and 32% to root + total aboveground litter at the Harz site in 1997.
Extensive damages in forests in southwest Germany were caused by the storm "Lothar" around noon and in the early afternoon of December 26th, 1999, respectively. For its forest meteorological analysis, general forms and important physical fundamentals of storm damages in forests are put together. Based on modelled wind loads on trees, critical wind speeds for windthrow and stem breakage can be derived. Characteristics of "Lothar" are comparatively small diameter, relatively high transfer speed, short-term extreme changes of air pressure and extremely strong gusts at its southwestern flank. Therefore, critical turning moments and wind speeds for windthrow and stem breakage were extensively exceeded in the regions south of the low pressure center of "Lothar". Recent models for the simulation of the windthrow risk of trees are related only to stationary conditions. They have to be extended by the dynamic component to consider effects of gusts and tree vibrations. By use of these improved models consequences of strategies for the reduction of the windthrow risk of trees can be simulated in an appropriate manner.
This paper, based on a literature review, presents a quantitative overview of the role of natural disturbances in European forests from 1850 to 2000. Such an overview provides a basis for modelling the possible impacts of climate change and enables one to assess trends in disturbance regimes in different countries and/or periods. Over the period 1950–2000, an annual average of 35 million m3 wood was damaged by disturbances; there was much variation between years. Storms were responsible for 53% of the total damage, fire for 16%, snow for 3% and other abiotic causes for 5%. Biotic factors caused 16% of the damage, and half of this was caused by bark beetles. For 7% of the damage, no cause was given or there was a combination of causes. The 35 million m3 of damage is about 8.1% of the total fellings in Europe and about 0.15% of the total volume of growing stock. Over the period 1961–2000, the average annual area of forest fires was 213 000 ha, which is 0.15% of the total forest area in Europe. Most types of damage seem to be increasing. This is partly an artefact of the improved availability of information. The most likely explanations for an increase in damage from disturbances are changes in forest management and resulting changes in the condition of the forest. Forest area, average volume of growing stock and average stand age have increased considerably, making the forest more vulnerable and increasing the resources that can be damaged. Since forest resources are expected to continue to increase, it is likely that damage from disturbances will also increase in future.
Wind-speed data from four sites in Denmark have been analyzed in order to obtain estimates of the basic wind velocity, defined as the 50 yr wind speed (10 min averages) under standard conditions, i.e., 10 m over a homogeneous terrain with the roughness length 0.05 m. The sites are Skjern (15 yr), Kegnæs (7 yr), Sprogø (20 yr), and Tystofte (16 yr). The measured data are wind speed, wind direction, temperature and pressure. The wind records are cleaned for terrain effects by means of WASP (Mortensew et al., Technical Report I-666 (EN), Risø National Laboratory, 1993. Vol. 2: User's Guide): assuming geostrophic balance, all the wind-velocity data are transformed to friction velocity and direction at standard conditions by means of the geostrophic drag law for neutral stratification. The basic wind velocity in 30° sectors are obtained through ranking of the largest values of the friction velocity pressure taken once every two months. The main conclusion is that the basic wind velocity is significantly larger at the west coast of Jutland than at any of the other sites . These results are in agreement with those obtained by Jensen and Franck (Technical Report, Danish Technical press, 1970) and by Abild (Technical Report R-522 (EN), Risø National Laboratory, 1994). A short discussion of the wind storm on the 3rd of December 1999 is included. It is demonstrated how the data can be applied to non-standard situations where the roughness length depends on the direction.
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