Bark Beetle Ips Typographus Research Articles

Current Problems and Tasks of Forest Protection in Poland

Abstract Current problems of forest protection concern the declining health of forest stands due to climate change and the resulting extreme weather events such as heat waves, droughts, hurricane winds, heavy rainfalls and floods. Repeated impacts of these factors increase susceptibility of forest stands to pest insects and fungal pathogens. Norway spruce (Picea abies [L.] H. Karst) is sensitive to high air temperatures and water shortage. Long lasting droughts during the last two decades, have been one of the reasons behind Norway spruce dieback due to severe outbreak of European spruce bark beetle Ips typographus (L.) in the mountainous regions of southern Poland. In the Scots pine (Pinus sylvestris L.) stands, water balance disorders have enhanced the colonization of weekend trees by steelblue jewel beetle Phaenops cyanea (F.) and engraver beetle Ips acuminatus (Gyll.), as well as contributed to the spread of fungal diseases caused by Gremmeniella abietina (Lagerb.) Cenangium ferruginosum Fr. and Sphaeropsis sapinea Fr. fungi. Water related stress leads to weakening of oak stands, which are attacked by Agrilus spp. beetles and pathogens from the genus Phytophthora. It is possible that long lasting droughts initiated the spread of infectious ash disease caused by Hymenoscyphus fraxineus (= Chalara fraxinea), which resulted in the epidemic of ash dieback throughout Europe. Until recently, the use of plant protection products was the most common method of forest protection against pest insects and pathogens. Poland’s accession to the European Union has affected the marketing and use of plant protection products in the country. The implementation of the EU legislation (Directive 91/414/EEC, Directive 2009/128/ EC and Regulation No 1107/2009) has resulted in decreased assortment of pesticides registered for the protection of forests. High costs and long registration process considerably limited the interest of producers in placing the plant protection products on the market. Systematic decrease in the number of plant protection products possible to register for use in forestry, as well as the principles of integrated plant protection established in the EU in 2014 call for seeking plant protection methods based on the natural enemies of pests, such as pathogenic microorganisms, parasites and predators. Therefore, contemporary forest protection requires the advancement of integrated methods for pest insect and disease control through developing methods of forecasting forest dangers, the use of natural enemies and agro-technical methods for regulation of pests, as well as the development of decision support systems as a tool facilitating introduction of integrated forest protection principles. Such support systems help to establish optimal terms for the implementation of protection measures, so as to increase their efficiency while limiting the use of chemical pesticides to an absolute minimum.

Modelling the predisposition of Norway spruce to Ips typographus L. infestation by means of environmental factors in southern Finland

New measures for effective monitoring and controlling of bark beetle infestations are needed as a response to intensified outbreaks caused by the climate change. Various environmental factors affect tree health and susceptibility, as well as stand predisposition to bark beetles. European spruce bark beetle Ips typographus L. abundance and outbreak frequency in Finland has significantly increased during the last decade. The ability to identify sites under a high risk of infestation would facilitate adaptation to this new situation and help target limited forest health management resources. Accordingly, our goal was to investigate the importance of various stand, soil and topographic characteristics in the assessing predisposition of Norway spruce dominated urban forest in southern Finland to I. typographus infestations. Information on the environmental factors was assessed in the field in 2014 and derived from a digital elevation model. Ips typographus infestation intensity was classified into three infestation index classes based on tree-wise symptoms of resin flow, discoloration and defoliation. Cumulative logit link models were utilized for investigating stand-level infestation probability. The best explanatory factors were aspect, slope, site type and soil texture. Models with the highest cumulative probabilities for severe infestation were linked with eastern aspect, moderate steep slope and rich site type fertility (0.72) and eastern aspect, shallow soil and rich site type fertility (0.71). Higher soil C/N ratios with east aspect and rich site type fertility was associated with an increased risk of severe infestation in a third model. The lowest risk was associated with southern and southwestern aspects, fine soil texture, moderate site fertility and gentle slopes.

Synthetic RapidEye data used for the detection of area-based spruce tree mortality induced by bark beetles

Tree mortality caused by outbreaks of the bark beetle Ips typographus (L.) plays an important role in the natural dynamics of Norway spruce (Picea abies L.) stands, which could cause far-reaching changes in the occurrence and duration of vegetation phenology. Field-based early detection of tree disturbances is hampered by logistic, terrain, and technical shortcomings, and by the inability to continuously monitor disturbances over large areas. Despite achievements in remote mapping of bark-beetle-induced tree mortalities, early warning has been mostly unsuccessful mainly because of the lack of spectral sensitivity and discrepancies in definitions of field- and image-based disturbance classes. Here we applied a method based on inter-annual phenology of Norway spruce stands derived from synthetic multispectral data to part of the Bavarian Forest National Park in Germany. We fused temporally continuous Moderate Resolution Imaging Spectroradiometer and discrete RapidEye data using a flexible spatiotemporal data fusion method to achieve validated 8-day RapidEye-like composites of normalized difference vegetation index for 2011. We assumed that the dead trees delineated on 2012 aerial photographs were those in which bark beetle infestations were initiated in 2011. Samples were drawn with variable-sized buffering to represent the areas prone to infestations and their surroundings. We applied a conditional inference random forest to select the best image date among the entire 46 synthetic datasets to best discriminate between the core infestation patches and their surroundings from the subsequent year. Of the discrete time points identified, day 281 of the year represented the highest discrepancy between aerial image-based dead trees and their surroundings. Classification results were significantly correlated with beetle count data obtained using pheromone traps. Our method provided valuable information for management purposes and enabled wall-to-wall mapping of stands prone to infestation and its uncertainty. The results offer potential implications for rapid and cost-effective monitoring of bark beetle outbreaks using satellite data, which would be of great benefit for both management and research tasks.

First record of the genus Microdispodides (Acari: Heterostigmata: Pygmephoridae) in Palaearctic, with description of a new species from Western Siberia, Russia

A new species, Microdispodides moseri sp. nov. (Acari: Pygmephoridae), from alcohol sediments containing bark beetle Ips typographus Linnaeus (Coleoptera: Curculionidae: Scolytinae) collected in pheromone traps in Western Siberia, Russia, is described. The genus Microdispodides Vitzthum, 1914 is recorded from Palaearctic for the first time. A key to species of Microdispodides is provided.

Application of optical unmanned aerial vehicle-based imagery for the inventory of natural regeneration and standing deadwood in post-disturbed spruce forests

ABSTRACTDisturbances caused by the European spruce bark beetle (Ips typographus L.) infestations are amongst the main drivers of forest ecosystem dynamics in stands dominated by Norway spruce (Picea abies [L.] Karst.). Monitoring the post-disturbance stand development including establishment of the new tree cohorts (regeneration) is of particular importance, and is conventionally done by time-intensive field surveys. Efficiency of techniques such as airborne light detection and ranging (LiDAR) or stereo photogrammetry is constrained due to their quality or costs in small-scaled and substantially heterogeneous post-disturbed areas. Small, multi-rotor unmanned aerial vehicles (UAVs) offer alternatives via their lower cost, temporal flexibility and high spatial resolution. We investigated the Digital Surface Models (DSM) derived from the UAV for inventories in post-disturbed sites of the Bavarian Forest National Park, Germany. We compared the numbers and structural attributes of detected living trees and snags from UAV data with standard stereo aerial photogrammetry using conventional field survey as a reference. Moreover, we processed the UAV data both by manual and automated tree recognitions. The results differentiated for individual tree classes (Living Spruce/Standing Deadwood and Individual/Grouped) showed varying performance with best results achieved for Standing Deadwood of moderate height. The UAV products were superior to aerial photography for the height retrieval: UAV-based data showed in average the root mean square error (RMSE) = 1.56 m, coefficient of determination R2 = 0.74 and bias = −0.73 m, compared to the aerial photogrammetry RMSE = 2.71 m, R2 = 0.17 and bias = −1.27 m. In particular, the heights of tall snags were more biased. Furthermore, the UAV data provided good results in crown diameter determination (RMSE = 0.13 m, R2 = 0.87, bias = 0.05 m). The automated recognition method was associated with qualitative and quantitative drawbacks compared to the manual method. Detection rates for trees and regeneration growing individually (60.7% and 39.1% for manual and automated method, respectively) were higher compared to regeneration in groups (28.6% and 17.8%). To conclude, the UAV-based inventory has clear advantages over aerial photogrammetry, especially for inventory of sites dominated by larger individual trees with sparse understorey. However, it cannot fully replace the field survey in post-disturbed sites with dense regeneration, where the performance can be augmented by combining UAVs with reduced fieldwork in different stand structural classes.

Successful reproduction and pheromone production by the spruce bark beetle in evolutionary naïve spruce hosts with familiar terpenoid defences

Abstract The European spruce bark beetle Ips typographus is a damaging pest on spruce in Europe. Beetle interactions with tree species originating outside the natural range of the beetle are largely unknown and may be unpredictable because trees without a co‐evolutionary history with the beetle may lack effective defences. The terpenoid composition and breeding suitability for I. typographus of the historic host Norway spruce Picea abies were compared with two evolutionary naïve spruces of North American origin that are extensively planted in North‐West Europe: Sitka spruce Picea sitchensis and Lutz spruce Picea glauca x lutzii. The bark of all three species had a similar chemical composition and similar levels of total constitutive terpenoids, although Norway spruce had higher total induced terpenoid levels. Beetles tunnelling in the three spruce species produced similar amounts of aggregation pheromone. Controlled breeding experiments showed that I. typographus could produce offspring in all three species, with a similar offspring length and weight across species. However, total offspring production was much lower in Sitka and Lutz spruce. Overall, the results of the present study suggest that I. typographus will be able to colonize Sitka and Lutz spruce in European plantations and in native spruce forests in North America if introduced there.

Effects of γ radiation on the reproduction and enteroendocrine cells of the spruce bark beetle Ips typographus and prospects for its control

The European spruce bark beetle Ips typographus is one of the most important pests of spruce forests in Europe. The present study investigated the feasibility of a sterile insect technique (SIT) for this pest control. Laboratory-reared males were exposed to various doses of γ radiation (0, 10, 30, 50, 70 and 90 Gy) and allowed to mate with laboratory-reared untreated females. The radiation significantly affected the number of viable offspring. Although females oviposited on average 16.0–18.8 eggs per maternal tunnel in all treatments, the number of larval tunnels per maternal tunnel observed after 4 weeks of development decreased from 17.3 in the control (0 Gy) to 4.5 in the 90-Gy group. Numerous oviposition sites without larval tunnels were observed in galleries when males received high doses (70 and 90 Gy) of γ radiation. Comparison of the sperm viability in the control and irradiated males did not reveal any statistically significant differences. Side effects of the irradiation were examined by immunostaining of the enteroendocrine cells. Two distinct types of cells were revealed with antibodies to neuropeptides allatostatin A and tachykinin in the midgut. The alimentary tracts of males receiving a high dose of radiation (90 Gy) showed a significantly decreased number of tachykinin-like immunoreactive enteroendocrine cells. This observation suggests potential radiation-induced damage of the digestive system, which could lead to a reduction in male fitness. The implications of these findings for successful use of SIT in spruce bark beetle control are discussed.

Comparison Analysis of Species Composition of Entomopathogenic Fungi Isolated from Bark Beetles (Coleoptera: Scolytidae)

The monitoring outbreaks of bark beetles, flight activity of imago and development of larvae were conducted with pheromone traps and trap logs. We found more than 50 dead adults with symptoms white muscardine from several points under the bark. Healthy adults of Ips typographus without any pathogenic symptoms collected from pheromone traps and trap logs under bark in the forest Czech Bohemian Switzerland (?eske Svýcarsko). For adaptation bark beetles Ips typographus in the laboratory conditions and excluded any other abiotic factors as a potential reason for their mortality. They were placed in bark in the Petri plates with filter paper and treated by 1 ml of entomopathogenic fungi conidial suspensions.The isolates Bcz38 and Inc2 showed low level of mortality of Ips typographus . But the isolate Bcz2, Bcz8, Bcz9, Bcz12-Bcz25 of B . bassiana and Bcz31 B . pseudobassiana had high virulence against of Ips typographus 100%.

A new species and new records of pygmephoroid mites (Acari: Scutacaridae, Neopygmephoridae, Pygmephoridae) associated with Ips typographus (Coleoptera: Curculionidae: Scolytinae) from Western Siberia, Russia

ABSTRACTA total of six pygmephoroid mite species are recorded in alcohol sediments containing bark beetle Ips typographus Linnaeus (Coleoptera: Curculionidae: Scolytinae), collected by pheromone traps in Western Siberia, Russia. A new species Scutacarus pseudoplurisetus sp. nov. (Scutacaridae) and little-known species Coleopygmephorus bogenschutzi (Mahunka and Moser, 1982) comb. nov. (from Pseudopygmephorus Cross, 1965) (Neopygmephoridae) are described and redescribed, respectively. Coleopygmephorus bogenschutzi is recorded from Russia for the first time. Scutacarus scolyti Mahunka and Moser, 1982 (Scutacaridae), Coleopygmephorus hylophilus (Cooreman, 1963) (Neopygmephoridae), and Elattoma crossi Khaustov, 2000 (Pygmephoridae) are recorded from Asia for the first time. Scutacarus muscocicola Sevastianov, 1983 (Scutacaridae) and Elattoma crossi are recorded for the first time as associates of Ips typographus. A key to the species of Coleopygmephorus is provided.http://www.zoobank.org/urn:lsid:zoobank.org:pub:0622B6D2-4DBA-4932-9218-F0E0EA3F9E49

European spruce bark beetle (Ips typographus, L.) green attack affects foliar reflectance and biochemical properties

The European spruce bark beetle Ips typographus, L. (hereafter bark beetle), causes major economic loss to the forest industry in Europe, especially in Norway Spruce (Picea abies). To minimise economic loss and preclude a mass outbreak, early detection of bark beetle infestation (so-called “green attack” stage – a period at which trees are yet to show visual signs of infestation stress) is, therefore, a crucial step in the management of Norway spruce stands. It is expected that a bark beetle infestation at the green attack stage affects a tree’s physiological and chemical status. However, the concurrent effect on key foliar biochemical such as foliar nitrogen and chlorophyll as well as spectral responses are not well documented in the literature. Therefore, in this study, the early detection of bark beetle green attacks is investigated by examining foliar biochemical and spectral properties (400–2000nm). We also assessed whether bark beetle infestation affects the estimation accuracy of foliar biochemicals. An extensive field survey was conducted in the Bavarian Forest National Park (BFNP), Germany, in the early summer of 2015 to collect leaf samples from 120 healthy and green attacked trees. The spectra of the leaf samples were measured using an ASD FieldSpec3 equipped with an integrating sphere. Significant differences (p<0.05) between healthy and infested needle samples were found in the mean reflectance spectra, with the most pronounced differences being observed in the NIR and SWIR regions between 730 and 1370nm. Furthermore, significant differences (p<0.05) were found in the biochemical compositions (chlorophyll and nitrogen concentration) of healthy versus green attacked samples. Our results further demonstrate that the estimation accuracy of foliar chlorophyll and nitrogen concentrations, utilising partial least square regression model, was lower for the infested compared to the healthy trees. We show that early stage of infestation reduces not only foliar biochemical content but also their retrieval accuracy. Our results further indicate that remote sensing measurements can be successfully used for the early detection of the bark beetle infestation. We demonstrated that bark beetle infestation at the green attack stage effects leaf spectral response as well as leaf biochemical properties and their retrievals from hyperspectral measurements.

A new species of Dolichocybe (Acari: Dolichocybidae) from Western Siberia, Russia

A new species, Dolichocybe sibiriensis sp. nov. (Acari: Dolichocybidae), collected in alcohol sediments containing bark beetle Ips typographus Linnaeus (Coleoptera: Curculionidae: Scolytinae), collected in pheromone traps in Western Siberia, Russia, is described. A key to species of Dolichocybe Krantz, 1957 is provided.

Simulating bark beetle population dynamics in response to windthrow events

The relationship between windthrow disturbance and outbreaks of European spruce bark beetle Ips typographus L. in European Norway spruce forests has been the focus of recent studies. However, the nature in which the spatial characteristics of windthrow events influence bark beetle population dynamics is rarely examined. This represents a significant gap in the literature, as our understanding of how spatial windthrow patterns influence bark beetles can be useful for management efforts to help mitigate large-scale bark beetle disturbance. The objective of this study is to simulate how windthrow events facilitate bark beetle population state transitions from endemic and epidemic levels using a spatially explicit agent-based model. We examined how the spatial extent of windthrow events and the size of tree clusters impacted by windthrow influence this state transition. The results show that the beetle population transition slows with increasing spatial extent of a windthrow event and with larger clusters of windthrown trees, while scattered patterns of windthrown trees accelerate the timing of this transition. This study contributes to our understanding of the role of large-scale wind disturbance in European bark beetle outbreaks. Moreover, it provides a basis for further research to discover the impact of potential forest management applications aiming to mitigate the risk of bark beetle outbreaks.

Comparative evaluation of pheromone activity for the European spruce bark beetle Ips typographus (L.) (Coleoptera, Scolytidae) and methods of their application

Comparative assessment of attractiveness of different pheromone products is presented and the possibility of using pheromone-baited sticky traps for identification of the pest foci and monitoring of its abundance is considered. The test variants showed high selectivity in the territory of the Tsarskoye Selo open-air museum. Pheromone with the addition of a-pinene and limonene was more effective when using barrier traps. During the season, 2636 beetles were captured in standard traps, 2431 beetles, in standard traps with the addition of a-pinene, and 2469 beetles, in standard traps with the same components and limonene. Comparison of the barrier and sticky traps showed the same tendency in the pest population dynamics revealed by the two types of traps (correlation coefficient 0.8862). The use of additional components increased the duration of pheromone activity. Thus, improvement of the component composition of pheromones and the types of traps is required for using them as tools to monitor the European spruce bark beetle abundance and assess the risk of damage to trees.

Diapause and overwintering of two spruce bark beetle species.

Diapause, a strategy to endure unfavourable conditions (e.g. cold winters) is commonly found in ectothermic organisms and is characterized by an arrest of development and reproduction, a reduction of metabolic rate, and an increased resistance to adversity. Diapause, in addition to adaptations for surviving low winter temperatures, significantly influences phenology, voltinism and ultimately population growth. We review the literature on diapause and overwintering behaviour of two bark beetle species that affect spruce‐dominated forests in the northern hemisphere, and describe and compare how these strategies can influence population dynamics. The European spruce bark beetle Ips typographus (L.) (Coleoptera, Curculionidae) is the most important forest pest of Norway spruce in Europe. It enters an adult reproductive diapause that might be either facultative or obligate. Obligate diapausing beetles are considered strictly univoltine, entering this dormancy type regardless of environmental cues. Facultative diapausing individuals enter diapause induced by photoperiod, modified by temperature, thus being potentially multivoltine. The spruce beetle Dendroctonus rufipennis (Kirby) (Coleoptera: Curculionidae) infests all spruce species in its natural range in North America. A facultative prepupal diapause is averted by relatively warm temperatures, resulting in a univoltine life cycle, whereas cool temperatures induce prepupal diapause leading to a semivoltine cycle. An adult obligate diapause in D. rufipennis could limit bi‐ or multivoltinism. We discuss and compare the influence of diapause and overwinter survival on voltinism and population dynamics of these two species in a changing climate and provide an outlook on future research.

The stability of the pheromones of xylophagous insects to environmental factors: An evaluation by quantum chemical analysis

The ground and excited states of the pheromone molecules produced by xylophagous insects (the bark beetle Ips typographus L., the black fir sawyer beetle Monochamus urussovi Fisch., and the black pine sawyer M. galloprovincialis Oliv.) were modeled using a quantum chemical method utilizing DFT (density functional theory) with the B3LYP functional. The absorption wavelengths (energies) and dipole moments were calculated; the transitions of electrons from occupied to empty molecular orbitals were considered. The computed data were used to assess the stability of pheromone molecules exposed to environmental factors, such as solar radiation and humidity.

Occurrence of Ips typographus (L.) after wind damage in the Kościeliska Valley of the Tatra National Park

Abstract At the end of 2013, Norway spruce stands in the area of the Tatra National Park were severely damaged by strong storms especially in the Kościeliska Valley region. In the following spring of 2014, a survey recording the occurrence of the spruce bark beetle Ips typographus (Coleoptera, Curculionidae, Scolytinae) was initiated in order to describe the dynamics of beetle reproduction in relation to protection measures executed in wind-damaged stands. Ten research plots with 20 trees each were established in a socalled active protection zone, where the broken and fallen trees had been processed and removed in 2014, and in a passive protection zone, where no actions were taken, and the dynamics of Norway spruce mortality due to bark beetle infestation including quantitative parameters (infestation density, sex ratio of beetle populations) were examined. The entomological analyses were performed on 25 × 25 cm large bark samples taken from four (active zone) or two (passive zone) tree sections. In the first year of the survey, no infested standing trees were recorded on the plots and the colonisation of fallen and broken trees was very weak. In the second year (2015), infestations appeared in larger numbers on the plots with passive compared to active protection but the infestation density was 0.89 mating chambers per 1 dm2 regardless of the protection status. In the third year (2016), most of the remaining living spruces had been infested with a mean density of 0.82 m.ch. per 1 dm2. In 2015, the proportion of females in the beetle population was 65.8% being higher in the active (68.4%) than the passive (64.0%) protection zone, while in 2016 the proportion was 63.5% and in this case slightly higher in the passive protection zone (63.9% as compared to 63.2%). These results are in accordance with patterns observed in wind-damaged Norway spruce stands of other areas in Poland and Europe and demonstrate the usefulness of forest management procedures in mitigating I. typographus outbreaks.

Storms, temperature maxima and the Eurasian spruce bark beetle Ips typographus—An infernal trio in Norway spruce forests of the Central European High Tatra Mountains

Norway spruce forests (Picea abies Karst.) of the Carpathian High Tatra Mountains have been subject to unprecedented tree mortality caused by attacks of the Eurasian spruce bark beetle (Ips typographus L.) in recent decades. The outbreaks were preceded and accompanied by wind throw events and periods of increased seasonal temperature.We obtained climatic data and data on tree mortality due to storm throw and bark beetles by using a combination of direct dead tree inventory and remote sensing techniques, and examined annual tree loss change over a 26-year period in a forest district of the Slovak High Tatra National Park. In particular, we found that the combination of the previous year’s maximum daily temperature sum, tree mortality caused by wind, and bark beetle-caused tree mortality best explained the annual tree loss change in nonlinear regression models. The number of trees infested by bark beetles clearly increased with maximum air temperature sums ranging from 2850 to 3150° days, but declined below or above this thermal optimum. Annual tree mortality clearly increased subsequent to years associated with seasonal temperature sums allowing for the development of sister broods. Given consistently favourable future climatic conditions for development of I. typographus populations in the study area, a possible shift from the now predominantly uni-voltine to multi-voltine bark beetle populations might increase attack pressure also at high elevation sites.

Is it possible and necessary to control European spruce bark beetle Ips typographus (L.) outbreak in the Białowieża Forest?

Abstract In response to the information published in ‘Forest Research Papers’ (vol. 77(4), 2016), regarding the problem of the European spruce bark beetle Ips typographus (L.) in the Białowieża Forest, we present our viewpoint on this issue. The role of the European spruce bark beetle in the Białowieża Forest is discussed based on the experience gained in Europe’s forests. We present the effects of I. typographus outbreaks on forest biodiversity as well as outbreak mitigation in the context of the processes taking place in semi-natural forests.

Interactions between windthrow, bark beetles and forest management in the Tatra national parks

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 (<∼250m), 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.

The Red-belted Bracket ( Fomitopsis pinicola ) colonizes spruce trees early after bark beetle attack and persists

Abstract The Red-belted Bracket (Fomitopsis pinicola) is one of the major decomposers of coniferous wood in Europe and can reach high densities after outbreaks of bark beetles. However, factors of dead wood type and decay stage, which determine the growth of reproductive biomass, i.e. basidiomes, remain unclear. In 2013, we surveyed 1280 dead wood objects and vital trees in spruce stands killed by the bark beetle Ips typographus in 2012, 2002, 1992 and in undisturbed stands for the presence, number, mean basidiome size and total volume of basidiomes. Living basidiomes were equally abundant on dead wood 1, 11, and 21 y after bark beetle outbreak, but were lacking on living trees. Our results indicate that F. pinicola is an effective early colonizer of the huge resource pulse of dead wood caused by the outbreak of bark beetles and basidiomes can persist for 21 y.