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Reverse engineering (RE) aims at the reproduction of products following a detailed examination of their construction or composition. Nowadays, industrial applications of RE were boosted by combining it with additive manufacturing. Printing of reverse-engineered elements has become an option particularly when spare parts are needed. In this paper, a case study was presented that explains how such an approach can be implemented in the case of products with asymmetric mechanical properties and using replacement materials. In this case study, a reverse engineering application was conducted on a textile machine spare part. To this end, the nearest material was selected to the actual material selection and some mechanical tests were made to validate it. Next, a replacement part was designed by following the asymmetric push-in pull-out characteristic. Finally, the finite element analysis with Additive Manufacturing was combined and validated experimentally.

Pheromone traps are used for monitoring I. typographus populations in Norway spruce stands of the Tatra National Park (TPN) in Poland. The presented study is based on the set of pheromone traps of precisely known location (23) located in the whole area of the TPN and operated continuously in 2010–2019. The data on the captures of beetles were compared with two kinds of data concerning the mortality: the area covered by standing dead trees (airborne photographs) in the no-intervention zone, and the volume of trees infested by bark beetles processed in the active protection zone. No relationship was found between the mean numbers of beetles captured yearly in all pheromone traps in the whole TPN area and the volume of infested trees removed from the stands in the active protection zone. The captures in the two selected study areas were correlated with the area of spots with dead trees in the 500 m circle around the traps, however, this correlation is not statistically significant. There is no relation of captures to the volume of processed infested trees. The captures decreased in the growing seasons after the wind damage, and increased markedly after the drought started in 2015. The results of pheromone trapping are affected by several factors, as wind damage and defence potential of trees resulting from their physiological status. Pheromone traps represent valuable source of information about the bark beetle I. typographus population dynamics, although the collected data do not enable direct definition of its population level, especially in the protected areas with different and unstable (changed in 2017) approach to the protection of stands. As most of the information on beetles is captured in the first half of the growing season, the data collected till the end of July are sufficient for monitoring purposes; thus, the trapping should be reduced to the period May–July.

Pine sawflies (Hymenoptera: Diprionidae) belong to the most common pests of Scots pine Pinus sylvestris L. in the area of the Regional Directorates of State Forests in Toruń and Gdańsk. The two most destructive species, Diprion pini L. in the area of Puszcza Bydgoska and Gilpinia virens (Klug) in Bory Tucholskie, were investigated in this study. Our main aim was to characterise the two species in the Bydgoszcz Forest District in RDSF in Toruń and Kaliska in RDSF in Gdańsk, respectively, based on data gathered during outbreaks between 1991 and 2011. For this purpose, a geometric database was created, containing information about the year of outbreak, number of larvae observed after tree felling as well as selected stand and site features including stand age and species composition, stocking index, canopy closure, site index, humidity and fertility. By analysing the occurrence of both species in relation to stand and site features, we were able to determine their environmental requirements, which are quite different from one another. D. pini preferred older stands, with a stocking index between 0.8–0.9, growing on fresh and dry coniferous sites, while species composition (share of pine), canopy closure or site index did not have any influence on its abundance. G. virens preferred middle-aged pure pine stands, with relatively open canopies, on fresh coniferous sites and poorer soils. The stocking index did not affect its occurrence.

In 2013–2014, a set of 30 pheromone traps baited with synthetic lures attracting I. duplicatus (Duplodor – 15 traps) and I. cembrae (Cembrodor – 15 traps) was installed in 6 altitudinal transects (1000–1400 m a.s.l., every 100 m of elevation) in the eastern, central and western part of the Tatra National Park (TPN) in Poland and operated during the entire growing season. The main aim of the survey was to check if and to what vertical extent these two species of bark beetles, not yet recorded, are presently distributed in TPN. Collected insects, including non-target Scolytinae and Cerambycidae, were determined. Overall 1896 Scolytid bark beetles belonging to 13 species, all occurring in the whole elevation range, were collected. I. duplicatus (28 specimens in total) was collected in the whole elevation profile, similarly as I. cembrae (718 specimens in total). Among Cerambycidae (282 individuals) belonging to 19 species, Rhagium inquisitor and Pidonia lurida, found on all elevations, were the most abundant; 8 species were collected on the highest locality. Pogonocherus decoratus was found for the first time in the Tatra. Results indicate the upward spreading of the studied insects as a possible effect of climate change and the resulting environmental conditions favourable for those organisms.

In March 2017, in the eastern part of the Tatra National Park in Poland, large windthrowns affected the passively and actively protected Norway spruce Picea abies stands. In early 2018, a set of 12 small research plots (20 trees on each plot) was established in the Norway spruce stands next to the windblown area – 6 in the stands under active nature protection (broken and fallen trees processed in 2017), and 6 in the stands under passive nature protection (trees left on the ground). Living trees on the plots were regularly checked during the growing season in order to identify and register the spruces infested by Ips typographus, which were dissected in 2 or 4 half-meter sections. 155 spruces (64%) infested by I. typographus were recorded on all 12 plots: 118 out of 120 (98%) in passive and 37 out of 120 trees (31%) in active protection. Mean infestation density calculated on 128 samples from 47 trees was higher under passive than under active protection (1.23 and 0.92 mating chamber per 1 dm2, respectively). Among 1709 gallery systems, those with 2 maternal galleries prevailed (63.0%); the mean share of females was higher in passive than in active protection zone (63.1 and 59.6% respectively). The mean number of progeny per one female was higher in active than in passive protection zone (20.23 and 19.12 respectively). I. typographus attack on standing trees had lower intensity in the stands previously subjected to the processing and removal of fallen and broken trees, which indicates positive effect of implemented active protection procedures. The parameters describing I. typographus population on attacked trees, as well as low activity of natural enemies, demonstrate its reproduction potential and resulting high risk of a new outbreak, according to the pattern known earlier from the other areas in Poland and Europe.

The low-cycle deformation of 304L austenitic stainless steel was examined in terms of energy conversion. Specimens were subjected to cyclic loading at the frequency of 2 Hz. The loading process was carried out in a hybrid strain–stress manner. In each cycle, the increase in elongation of the gauge part of the specimen was constant. During experimental procedures, infrared and visible-range images of strain and temperature fields were recorded simultaneously using infrared thermography (IR) and digital image correlation (DIC) systems. On the basis of the obtained test results, the energy storage rate, defined as the ratio of the stored energy increment to the plastic work increment, was calculated and expressed in reference to selected sections of the specimen. It was shown that, before the specimen fracture in a specific area, the energy storage rate is equal to zero (the material loses the ability to store energy), and the energy stored during the deformation process is released and dissipated as heat. Negative and close-to-zero values of the energy storage rate can be used as a plastic instability criterion on the macroscale. Thus, the loss of energy storage ability by a deformed material can be treated as an indicator of fatigue crack initiation.

At the end of 2013, strong wind destroyed spruce stands on large areas of Kościeliska Valley in Tatra Mts. in Poland. In 2015–2017, 304 bark samples were collected from 106 spruces; 25 cm × 25 cm large samples were taken from 2 or 4 sections of infested trees in July/August each year. The infestation density, sex ratio, length of maternal galleries, number of progeny and impact of natural enemies were recorded. The infestation density in individual years was 0.79–0.86 mating chambers per dm2, the average length of maternal gallery (55.2–56.6 mm) did not differ between years, The average number of progeny per female from 3-year pooled data was 18.22, the highest in 2015 (27.4) then collapsed to 15.5–16.8. The gallery systems with 2 females, in which the reproduction success was the highest, dominated (62.6%). The frequency of parasitoids or entomopathogens was very low (2–20% mortality rate in 19 bark samples). Possible reasons of relatively low reproduction success regardless generally favourable breeding conditions and its collapse after first year, such as high infestation density and low survival rate of larvae because of climatic conditions (drought), are discussed. Taking into account the described population features, very intense tree mortality and mechanisms known from the other wind events, further development of the outbreak can be expected in this area.

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.

Spruce bark beetle Ips typographus (L.) (Col.: Curculionidae, Scolytinae) outbreaks occur in managed and protected forests alike, but although known of for a long time, management and control of this insect is a controversial subject due to the forests’ diverse nature and protection status. In this paper, an overview of the bark beetle, conditions leading to outbreaks, natural enemies and the efficiency of control measures is presented and put into perspective with regards to the current controversies concerning outbreak management. The Białowieża Primeval Forest is central to this discussion, because the area remains divided into parts with different nature protection statuses. Ideas concerning the current but also future outbreak progress and possible issues with the management of natural resources in this area are presented.

Norway spruce trees weakened by soil drought and progressive die-off of mycorrhizas in root systems become susceptible to infection by rhizomorphs of Armillaria spp. The developing mycelium of this necrotroph induces resin channels in wood, and the induced resin releases some volatile compounds which falsely signal bark beetles that it is safe to invade the host. As a result of the developing beetle outbreak, host trees die, becoming a long-term stock of substrate for the fungus in its saprotrophic stage. This hypothesis is discussed as a fungal survival strategy.

Outbreaks of the European spruce bark beetle Ips typographus kill extensive areas of Norway spruce forests in Central Europe, affecting both protected areas and neighboring commercial forests. In protected areas, uncontrolled (non-intervention) management allows natural beetle-induced tree mortality, while in commercial forests infested trees are salvage-logged in order to lower I. typographus numbers and stabilize wood production. However, the effects of active pest controls on I. typographus population are often ambiguous, and little is known about how antagonists, beetle density, or intraspecific competition help terminate I. typographus outbreaks. To answer this question, we studied I. typographus population development, breeding performance, and natural antagonists under intervention and non-intervention management in the High Tatra Mts. from 2014 to 2017. We used sentinel logs and windthrown trees, following the current legislation in Tatranský narodný park (TANAP, Slovakia) and Tatrzanski Park Narodowy (TPN, Poland). Both parks are mountainous, are covered by Norway spruce forests that have been extensively affected by windthrows and extensive I. typographus outbreaks over the last 20 years, and are zoned under intervention and non-intervention types of management. We found that I. typographus was a dominant species and that its numbers gradually increased during the study, but that the numbers of maternal galleries in sentinel logs (from 50 to 300 per m2) and sex ratio (1 male:2.5 females) remained the same among years. The length of maternal galleries and egg production (per m2 of bark), however, gradually declined, and breeding performance decreased from 10 daughter beetles per female in 2014 to almost zero in 2017. These parameters did not significantly differ between intervention and non-intervention sites. Antagonists were not abundant and had limited effects on I. typographus numbers. Active intervention did not affect I. typographus population dynamics or rates of parasitism but increased numbers of Thanasimus beetles, which are predators of bark beetles. In other words, intervention increased the numbers of some natural enemies of I. typographus but did not affect I. typographus population dynamics. Because control measures did not reduce I. typographus numbers in the intervention zone, the natural ecological processes crucial for maintaining ecosystem functioning and biodiversity were evidently preserved.

The study estimated the efficacy of a net coated with alpha-cypermethrin used to protect Norway spruce [Picea abies (L.) H. Karst] wood against bark beetle infestations. The inside of the net was coated with 100 mg/m2 of alpha-cypermethrin. The studies carried out in 2010 and 2011 took place in southern Poland in the Beskid Żywiecki and Beskid Sądecki mountains in P. abies stands threatened by Ips typographus (Linnaeus, 1758). The research material consisted of wood logs taken off of 70–80-year-old P. abies trees. The logs were wrapped in the net in the early spring before spring swarming of bark beetles. The unwrapped logs were considered as the study controls. An evaluation of the treatments was performed after 2 months. The evaluation was based on the counting of bark beetles galleries found after removing the bark from the wrapped and unwrapped logs. There were no insect galleries on the wrapped logs. The net was a barrier, on which bark beetles died. About 10 dead I. typographus beetles were found on 0.01 m2 of the net surface. On the bark from the unwrapped-control logs there were 3,156 galleries/entrance holes of bark beetles, in total, of which 73% belonged to I. typographus, 13% to Pityogenes chalcographus (Linnaeus, 1761), and almost 10% to Xyloterus lineatus (Oliv.). These results indicated the high efficacy of the net coated with alpha-cypermethrin used for the protection of Norway spruce wood against the bark beetles. At the same time, the net was found to have a negative effect on non-target entomofauna, mainly Hylobius spp., Thanasimus formicarius (L.), and Tetropium castaneum (F.). However, the use of a net did not affect other predatory (Carabidae) and parasitic (Ichneumonidae and Tachinidae) entomofauna.

International audience; AbstractKey messageUnder an outbreak scenario in a buffer zone of a protected area, bark beetle-caused tree mortality was modulated by earlier natural disturbances (wind and bark beetles), sanitary management and seasonal temperature. In buffer zones, the effects of sanitary management on tree mortality remained limited due to the migration of bark beetles from unmanaged areas.ContextThe European spruce bark beetle (Ips typographus L.) is regarded as an economically significant pest of Norway spruce (Picea abies [L.] Karst). However, in protected areas, it is regarded as a keystone species for biodiversity. This results in two contrasting management strategies that meet in buffer zones of protected areas.AimsTo assess which environmental and management variables are most important for tree mortality in an ongoing bark beetle outbreak and to gain a better understanding of the challenges and recommendations for buffer zone management under the influence of nearby unmanaged stands in a protected area.MethodsNorway spruce tree mortality was assessed in 419 forest stands in the High Tatra Mountains. To account for spatial and temporal autocorrelations, generalized additive mixed models (GAMM) were used, and an information-theory (I-T) approach was adopted for model selection to test the influence of environmental variables, natural disturbances and the previous year’s sanitary cutting on bark beetle-caused tree mortality.ResultsIn buffer zones, P. abies tree mortality caused by I. typographus was positively correlated to natural disturbances and sanitary cutting in the previous year.ConclusionThe previous year’s sanitary cutting, maximum temperature sums, wind disturbance and trees left in no-intervention stands contributed to tree mortality in buffer zones. In these zones, the decrease of tree mortality in response to sanitary management remained limited due to the migration of bark beetles from unmanaged areas. However, sanitary management in buffer zones remains necessary for the isolation of bark beetle outbreaks in unmanaged areas.

The current nature of forest management in Poland reflects its history and more than 100 years of economic activity affecting forests since independence in 1918. Before that time, different forest management models were used, related to the nature of the Prussian economy in the north of the country, the Russian economy in the central-eastern part, and the Austrian economy in south-eastern Poland. The consequence of these management models, as well as the differing climate zones in which they were used, resulted in varied forest health. Since the end of World War II, forest coverage within Poland‘s new borders has increased from 20.8% to currently 29.6%, mainly as a result of afforestation of wastelands and former agricultural lands. This paper describes changes in the health of forests and their biological diversity in Poland in the context of weather extremes, species composition, forest management, the forest industry, and damage from insects and pathogenic fungi over the last 30 years.