Tomicus Piniperda Research Articles

Performance ofTomicus yunnanensisandTomicus minor(Col., Scolytinae) onPinus yunnanensisandPinus armandiiin Yunnan, Southwestern China

Pine shoot beetles,Tomicus yunnanensisKirkendall and Faccoli andTomicus minorHartig (Col., Scolytinae), have been causing substantial mortality to Yunnan pine (Pinus yunnanensisFranch) in Yunnan, southwestern China, whereas only a few Armand pine (Pinus armandiiFranch) were attacked by the beetles. In order to evaluate the suitability ofP. armandiias host material for the twoTomicus, adults of bothTomicuswere caged on living branches and felled logs of the two pines during shoot feeding and trunk attack phase, respectively. More beetles survived on the living branches ofP. yunnanensisthan onP. armandii.Tomicus yunnanensisandT. minorproduced similar progeny in the logs of the two pines. The sex ratio and developmental period were not affected by host species, but the brood beetles emerging from Armand pine weighed less than those from Yunnan pine, suggesting thatP. armandiiare less suitable to be host ofT. yunnanensisandT. minor.

Crown transparency, tree mortality and stem growth of Pinus sylvestris, and colonization of Tomicus piniperda after an outbreak of Gremmeniella abietina

In the year 2000, large areas of forest in Sweden, mainly 30–50 year old Pinus sylvestris (L.) stands, were attacked by the fungus Gremmeniella abietina (Lagerb.) Morelet. The aims of this study were to investigate: (i) the relationship between G. abietina-induced tree crown transparency (CT) and P. sylvestris (L.) tree mortality; (ii) the influence of CT levels on stem growth; (iii) the recovery of the crown; and (iv) the association of CT and colonization by Tomicus piniperda (L.). Thirty-five permanent sample plots were established in five P. sylvestris stands (38–46 years old), infested by G. abietina, and 23 plots in four reference stands, not obviously infested. During the 5 years following the attack, the total mortality amounted to 454 trees ha −1 and 7.8 m 2 ha −1, on average, in the five infested stands, corresponding to 42% of the trees and 34% of the basal area at the time of the attack. Most of the mortality occurred within 2 years of the attack. The mortality of individual trees (2002–2005) was found to be related to the crown transparency (CT), the position of needle loss within the crown and the tree diameter at breast height. Based on our modeling, the probability of mortality was substantially increased if the initial CT-value was higher than 85%. Growth reductions were detected for individual trees with an initial CT of >c. 40%. In contrast, trees with a low initial CT (<c. 40%) were not affected and even exhibited increased growth. In the five infested stands, the reductions in basal area and volume increment were estimated to be 26–58%, and, 42–73%, respectively, during the five growing seasons after the attacks. The trees in the infested stands that were still alive in spring 2005 had started to recover in terms of CT. Breeding of T. piniperda on the P. sylvestris (L.) stems occurred almost exclusively on stems with a CT > 90%. The data from this study suggest that when a P. sylvestris (L.) stand has been attacked by G. abietina, trees with a CT above 80% should be felled; the remaining trees will have a high probability of survival and resistance to successful breeding by the T. piniperda.

A Study on the Growth and Management Status of Mansongjung forest in Hahoe, Andong

A village forest is a place for intentional purposes with natural and ecological grounds including history, culture and faith. The study investigates and analyzes land use, soil status, flora, vegetation, disease and insects, uses and management of Mansongjeong (pine tree) forest in Hahoe, Andong designated as natural monument for the purpose of preserving the Village forest. This diagnoses current vegetation of the forest and secures basic information to propose sustainable management. The land use analysis showed that wetlands and streams around the forest accounted for 44.2%, peripheral environment with high humidity and the soil analysis stated that the pH was proper but organic materials, total nitrogen and effective phosphorous reached below the average or overfeeding. The flora consists of 119 kinds including 37 families, 13 varieties, 1 species and 1 frost aster (Aster pilosus Willd) and there are 22 naturalized species. The vegetation stated that there were 859 Pine trees (Pinus densiflora), 6 zelkovas (Zelkova serrata), 1 nut tree (Castanea crenata) and 1 plum tree (Prunus mume), showing that the pine trees dominated in the upper part of the forest. There shall be consideration for new or existing forest with tree planting by excluding factors which may affect traditional tree-planting pattern in region with old trees and forming natural generation congress in the future. Pest research discovered that there were 9 kinds including Rhyacionia duplana (Hubner), aphids, mites, Tomicus piniperda (Linne) and zelkova silverfish. Usage and management results showed that the number of visitors was small but sharply increased during the festival season of Hahoe Village and there were 14 facilities in 2 kinds. A project on protecting the forest was designated and performed once in 2006. Systemic and pest managements considering ecological features of shade intolerant trees like pine trees through proper light penetration and adjusting crowd rates and regulating number of visitors are required to sustain the Mansongjeong Forest.

Use of pheromone traps against Tomicus piniperda and Tomicus minor in the Kazbegi National Park, Georgian Republic

In the forested lands of Georgia Kazbegi National Park, some kinds of insects have been significantly harming the bark beetle of trees as their population increases. The most harmful species within the 100 ha area of the national park, where Pinus sylvestris L. var.hamata (Steven) (Scots Pine) trees settle have been identified as Tomicus piniperda (L.) and Tomicus minor (Hartig) using bio-technic method (pheromone traps), has been implemented against them. The damages of T. piniperda and T. minor were measured from all the Scots Pine in Kazbegi National Park in 2008. One of the newly developed control methods used in the field with intensive T. piniperda and T. minor populations is the bio-technic method. Prepared pheromone traps were hung up on trees located in various places and captured insects were counted and the results recorded in 2008. T. piniperdaand T. minor trapped in pheromone traps, hung from the pines of the Scots Pine outbreak area were significantly greater in study area (109.5±2.1 and 118.2±1.8 beetle/trap, both species respectively). Key words: Tomicus piniperda, Tomicus minor, pheromone trials, Kazbegi National Park, Georgia.

Bark beetle fauna (Coleoptera: Scolytinae) of the coniferous forests in the Mediterranean region of Western Turkey, with a new record for Turkish fauna

Scolytinae (Coleoptera: Curculionidae) species and their host plants of coniferous forests of the Mediterranean region of Western Turkey were determined between 2006 and 2008. A total of 27 species of Scolytinae were collected from 59 different sites in Afyonkarahisar, Antalya, Burdur, Denizli, Isparta, and Muğla provinces. Hylastes angustatus (Herbst), H. linearis Erichson, Tomicus destruens (Wollaston), Hylurgus ligniperda (Fabricius), Pityogenes calcaratus (Eichhoff), P. pennidens Reitter, Orthotomicus robustus (Knotek), and O. suturalis (Gyllenhal) were recorded as new species for the Scolytinae fauna of the Mediterranean region of Western Turkey. Orthotomicus robustus (Knotek) was recorded for the first time from Turkey.

Prothallonema tomici n. sp. (Tylenchida: Sphaerulariidae) parasitising Tomicus piniperda (Coleoptera: Curculionidae: Scolytinae) in Bulgaria

AbstractProthallonema tomici n. sp. (Tylenchida: Sphaerulariidae) is described as a parasite of the bark beetle Tomicus piniperda (Linnaeus) (Coleoptera: Curculionidae: Scolytidae). The new species is characterised by the relatively short body (0.3-0.5 mm) and short prolapsed uterus ((0.16-0.44) × (0.065-0.15) mm), relatively anterior position of the vulva (83.8-85.5%), stylet with fine asymmetrical basal knobs, hemizonid and hemizonion, four incisures, subterminal phasmids and tail terminus always curved dorsad. The entomoparasitic and mycetophagous generation were observed in the body cavity of T. piniperda. Comparing the two generations of J4 showed that the mycetophagous generation had a longer and more robust body, shorter pharynx and tail, longer reproductive system and vulva located further posteriorly. It can be concluded that, in the haemocoel, the entomoparasitic generation can develop through all stages whilst the mycetophagous generation develops to the J4 and then dies.

Pine Shoot Beetle, Tomicus piniperda (Linnaeus) (Insecta: Coleoptera: Curculionidae: Scolytinae)

Revised! EENY-321, a 6-page illustrated fact sheet by Michael C. Thomas, Wayne N. Dixon, and Thomas R. Fasulo, is part of the Featured Creatures collection. It describes this serious pest of pines in Europe that is considered a potential threat to some of the pine species cultivated in Florida — distribution, identification, biology, economic importance, survey, and management. Includes references. Published by the UF Department of Entomology and Nematology, September 2010. EENY-321/IN596: Pine Shoot Beetle, Tomicus piniperda (Linnaeus) (Insecta: Coleoptera: Curculionidae: Scolytinae) (ufl.edu)

Species Composition, Seasonal Activity, and Semiochemical Response of Native and Exotic Bark and Ambrosia Beetles (Coleoptera: Curculionidae: Scolytinae) in Northeastern Ohio

In 2007, we surveyed the alien and endemic scolytine (bark and ambrosia beetles) fauna of northeastern Ohio, and for the most abundant species, we characterized their seasonal activity and response to three semiochemical baits. In total ,5,339 scolytine beetles represented by 47 species and 29 genera were caught in Lindgren funnel traps. Three species constituted 57% of the total catch, including Xylosandrus germanus (Blandford), Tomicus piniperda (L.), and Dryocoetes autographus (Ratzeburg). Of the total captured, 32% of the species and approximately 60% of the individuals were exotic, suggesting that exotic species numerically dominate the scolytine fauna in some urban areas. More native and exotic species were caught in traps baited with ethanol alone than in traps baited with other lures. However, significantly more individuals, especially of T. piniperda, D. autographus, Gnathotrichus materiarius (Fitch), and Ips grandicollis (Eichhoff), and species were caught in traps baited with ethanol plus alpha-pinene than in traps baited with ethanol alone or the exotic Ips lure. This suggests that among these baits, the ethanol plus alpha-pinene baits may be useful in maximizing scolytine beetle catches of these species within this region. Species diversity and richness for both native and exotic beetles was greatest in traps baited with ethanol alone. The period of peak trap capture varied depending upon species: X. germanus was most abundant in traps in mid-May and early-August; T. piniperda in mid-May; D. autographus in early June, mid-July, and mid-September; Anisandrus sayi Hopkins and G. materiarius in mid-May, mid-July, and early September; and I. grandicollis in early April, mid-July, and late September.

Response of &lt;I&gt;Tomicus yunnanensis&lt;/I&gt; (Coleoptera: Scolytinae) to Infested and Uninfested &lt;I&gt;Pinus yunnanensis&lt;/I&gt; Bolts

Tomicus yunnanensis Kirkendall and Faccoli (Coleoptera: Curculionidae: Scolytinae) is a newly described pine shoot beetle found in southwestern China. This beetle has affected >200,000 ha of Pinus yunnanensis (Franchet) forests over the past 30 yr. After maturation feeding in the shoots, adults attack the boles in December to produce a new generation. A hanging bolt study was initiated in November 2006 to detect the beetle flight patterns and to test if dispersing beetles respond to infested and uninfested material. Treatments tested were females only, males only, male and female pairs, and uninfested bolts. Beetles were collected on the bolts between 9:30 and 18:30, with peak catch in the afternoon between 14:00 and 18:30. No beetles were collected during the dark. Though trunk attacksin the field were observed in November, beetles were first collected on the bolts in January. No beetles were captured after March. Differences in numbers of beetles collected between treatments with infested bolts varied by month, but uninfested bolts always attracted fewer adults.

Water stress affects Tomicus destruens host pine preference and performance during the shoot feeding phase

• The effect of water stress on host selection and performance during the shoot feeding phase, by the Mediterranean pine shoot beetle Tomicus destruens, was studied.• Young potted Pinus pinaster plants were subjected to two water supply regimes: (i) well watered; (ii) 4–5 months of moderate drought stress. Plant volatile organic compound (VOCs) emissions were collected by SPME and analysed by GC/MS. • In tests with paired plants, the number of holes and tunnels excavated by beetles in well watered pines was significantly larger than in stressed plants, whereas in no-choice tests no differences occurred.• Beetle survival was significantly higher on well watered, than on stressed pines ( p = 0.006), while fat contents also increased ( p = 0.09).• Plants could be assigned to treatments based on VOCs emissions, stressed pines emitting more myrcene and less β-pinene than well watered ones.• It is concluded that during the shoot feeding phase, T. destruens preferentially attacks non-stressed plants, in detriment of stressed ones, upon which a higher fitness is attained.• The role of pines VOCs emissions under moderate drought stress, in the host selection and colonization process by the pine shoot beetle, is discussed.

Predators of Scolytinae (Coleoptera: Curculionidae) species of the coniferous forests in the Western Mediterranean Region, Turkey.

Scolytinae (Coleoptera: Curculionidae) species cause economically damage every year in coniferous forests of the Western Mediterranean Region of Turkey. Among these species especially Orthotomicus erosus (Wollaston), Orthotomicus tridentatus Eggers, Tomicus destruens (Wollaston), Tomicus minor (Hartig), Ips sexdentatus (Boerner) and Pityokteines curvidens (Germar) are the most common. The number of trees being killed by Scolytinae species has increased significantly in recent years throughout the region. Predator species are important factors in the dynamics of these pests. In this study, it was aimed to determine predator species of bark beetles in the coniferous forests of Western Mediterranean Region. Specimens were collected from 24 sites throughout the region between 2006 and 2008. Totally nineteen predator species of Scolytinae belonging to ten families of three orders were presented from the Western Mediterranean Region of Turkey in bark beetle galleries on coniferous trees. Among these species Plegaderus vulneratus (Panzer), Nemosoma pliginskyi Reitter and Nemosoma cornutum Sturm were the first records for the Turkish fauna. Aulonium ruficorne (Olivier), Corticeus fraxini (Kugelann), Thanasimus formicarius (Linnaeus), Raphidia ophiopsis Linnaeus, Rhizophagus depressus (Fabricius) and Temnochila coerulea (Olivier) were found as the most common predator species.

Extensive tree health monitoring networks are useful in revealing the impacts of widespread biotic damage in boreal forests

We surveyed the regional distribution of conifer defoliation in Finland with an extensive monitoring network during 1995-2006 (EU Forest Focus Level I). The average defoliation in the whole Finland was 10.3% in pine and 19.9% in spruce. The sharp changes were often related to abiotic and biotic factors. The mean age of the stand explained more than one half of the between-plot variance in defoliation. In a variance component analysis, the main effect of years was negligible, while most of the random variation was due to plot main effect and plot x year interaction. About one fifth of the defoliation could be attributed to abiotic or biotic damage, and there were strong local correlations, e.g., between the changes in defoliation and degree of pine sawfly (Diprionidae) damage. There were clear temporal and spatial patterns in the incidence of the most important causes [Scots pine: Scleroderris canker (Gremmeniella abietina), pine shoot beetles (Tomicus sp.), and pine sawflies (Diprion pini, Neodiprion sertifer); Norway spruce: rust fungi (primarily Chrysomyxa ledi)]. Our results suggest that extensive monitoring networks can reveal useful information about the widespread outbreaks of pest organisms (insects and fungi) already in their increase phases, giving some time for management decisions. In a changing climate, large-scale, regular monitoring of tree health, including abiotic and biotic causes, is more important than ever before.

Breeding performance of Tomicus destruens at different densities: the effect of intraspecific competition

AbstractIn many bark beetles (Coleoptera: Curculionidae: Scolytinae), intraspecific competition is a limiting factor governing their population dynamics. The aim of this study was to evaluate the effect of increasing infestation densities on the breeding performance of Tomicus destruens (Wollaston), one of the main pests of Mediterranean pine forests. Six densities (ranging from 0.25 to 1.50 females dm−2) were tested under laboratory conditions on stone pine logs, assessing the mortality of eggs, larvae, and pupae, and recording the number of emerging adults. Density significantly affected the fertile tract of the maternal galleries, i.e., those containing eggs, which was shorter at densities higher than 0.75. Numbers of eggs, larvae, pupae, and adults per female decreased markedly when density increased from 0.25 to 1.5, although differences were statistically significant only at a density of 0.75 and higher. The lowest mortality was found in larvae reared at a density of 0.25 (17.7%) and the highest in pupae at 1.5 (84.8%). Increasing density affected the pre‐emergence stages in different ways, with pupae and larvae suffering the highest increases in mortality (39.5 and 163.6%, respectively). The breeding performance of T. destruens (number of eggs laid reaching adulthood) progressively decreased from 17 to 4% with increasing densities, although at low infestation, the mean number of emerging adults per dm2 of bark increased with density, showing a positive trade‐off between female fecundity and female density. In conclusion, breeding densities higher than 0.75 female dm−2 decreased female fecundity and elicited high mortality, mainly in larvae.

Complex postglacial history of the temperate bark beetle Tomicus piniperda L. (Coleoptera, Scolytinae)

Tomicus piniperda is an economically important pine bark beetle infesting European Pinus spp. stands. We sequenced and analyzed 797 bp of the mitochondrial genome from individuals obtained from 34 populations sampled throughout the European range. We obtained 36 haplotypes, from which a haplotype network was constructed. In the Iberian Peninsula, high-genetic variability was detected with numerous endemic haplotypes. In contrast, the other European populations were less diverse with a single haplotype predominating from the Pyrenees to Scandinavia. Nevertheless, even within Europe, a few populations showed significant amounts of diversity. Four groups were obtained by Spatial Analysis of Molecular Variance, illustrating the regional characteristics of the species. T. piniperda had multiple fragmented refugia in the Iberian Peninsula. These currently isolated populations only partly contributed to postglacial re-colonizations of Northern Europe during interglacials. Nevertheless, few long-range migration events up to Northern Europe were detected, mostly originating from the Pyrenees. In the rest of Europe, the phylogeographical patterns were unclear, because of repeated cycles of contraction and expansion. The genetic analysis showed one glacial refugium in North-Central Europe, whereas other refugia most likely occurred in the Southern Alps, Apennine and the Balkans. The phylogeographical pattern depicted here reflects partly the postglacial history of the beetles' main host tree P. sylvestris.

Description of the Yunnan shoot borer, Tomicus yunnanensis Kirkendall & Faccoli sp. n. (Curculionidae, Scolytinae), an unusually aggressive pine shoot beetle from southern China, with a key to the species of Tomicus

Description of the Yunnan shoot borer, Tomicus yunnanensis Kirkendall & Faccoli sp. n. (Curculionidae, Scolytinae), an unusually aggressive pine shoot beetle from southern China, with a key to the species of Tomicus

Responses of the Mediterranean Pine Shoot Beetle Tomicus destruens (Wollaston) to Pine Shoot and Bark Volatiles

The pine shoot beetle Tomicus destruens has two dispersal phases per generation. In the first, mature adults move toward trunks of dying pines to lay eggs; in the second, callow adults move toward the shoots of healthy pines for maturation feeding. However, there is no information on the chemical stimuli that govern host selection by T. destruens adults. The aims of this study were: (1) to identify the volatiles released by shoots and bark of stone pine that are behaviorally and electrophysiologically active on T. destruens; (2) to verify which blends and concentrations of such volatiles are differently active on males and females, as well as on callow and mature adults, during the two host search phases (breeding and feeding). A four-arm olfactometer was used to test the behavior of walking T. destruens adults toward various sources of volatiles including fresh shoots and bark, their collected volatiles, and two synthetic blends. For each odor, the behavior of both callow and mature males and females was recorded individually. Shoot and bark extracts were analyzed by coupled gas chromatography and mass spectrometry (GC-MS), and tested by gas chromatography coupled with electroantennography (GC-EAD) on T. destruens males and females. Two blends of two (alpha-pinene and beta-myrcene; blend A) and three (alpha-pinene, beta- myrcene, and alpha-terpinolene; blend B) synthetic compounds, chosen among those that induce EAD responses and known to be attractive for other bark beetle species, were tested in the olfactometer at five concentrations. Insect behavior was affected by the degree of sexual maturation but not by sex. Callow insects were attracted by shoots and their extracts, while mature individuals by bark and its extracts. Six extracted compounds were active on T. destruens antennae: limonene, (Z)-3-hexen-1-ol and beta-caryophyllene, alpha-pinene, beta-myrcene, and alpha-terpinolene. alpha-Terpinolene, released only by bark, was active only on mature insects, whereas (Z)-3-hexen-1-ol, released only by shoots, was active only on callows. Males and females showed similar EAD responses. Of the six extracted volatiles, two were attractive for callow adults (blend A) and three for matures (blend B). In both cases, responses were positively correlated with blend concentration, although a repellent effect was noted at the highest concentrations.

Kairomonal responses of Tomicus destruens (Col., Scolytidae) to host volatiles α‐pinene and ethanol

AbstractThe Mediterranean pine shoot beetle Tomicus destruens is one of the most damaging bark beetles attacking Mediterranean pine forests in southern Europe and north Africa. We studied the attractiveness of the host volatiles α‐pinene and ethanol at a range of release rates, alone or in combination, to T. destruens, in order to develop an attractive lure for the management of this beetle. T. destruens was attracted slightly to the host volatile α‐pinene, but a strong synergistic effect was found in the attraction towards monoterpene when ethanol was added to the bait. The highest catches of T. destruens were obtained by the optimal blend releasing 300 mg/day of α‐pinene and 900 mg/day of ethanol. In contrast to data reported for the related species T. piniperda, Mediterranean pine shoot beetles were clearly attracted to baits releasing ethanol alone (1350 mg/day). trans‐Verbenol, which was also added to host volatiles in some tests, did not affect the response. The use of the attractive blend proposed would have a low impact on the natural enemy population of Thanasimus formicarius because of asynchronies in flight periods. Other non‐target insects, such as the facultative predator or competitor Oxipleurus nodieri, were also significantly attracted. These results allow the development of an operative lure for the effective monitoring of T. destruens, although improvements by the addition of other host volatiles should be studied.

Description of the Yunnan shoot borer, Tomicus yunnanensis Kirkendall &amp;amp; Faccoli sp. n. (Curculionidae, Scolytinae), an unusually aggressive pine shoot beetle from southern China, with a key to the species of Tomicus

We describe a new and highly aggressive species of pine shoot beetle, Tomicus yunnanensis Kirkendall &amp; Faccoli, which has been decimating Pinus yunnanensis forests in southwest China for almost three decades. This species was confused with T. piniperda until recent molecular studies showed the SW China populations to be quite divergent from T. piniperda of northeast China and Europe. The clearest morphological differences between these two species lie in the surface sculpture of the elytra: the new species has more widely spaced interstrial granules on the elytral disc, the punctures of interstria 2 on the declivity arranged irregularly and those of striae 1 and 3 smaller. The new species also has dense small hairs on the tip of the antennal club, while T. piniperda has only scattered small hairs on that segment. Mature T. piniperda specimens are uniformly black, while those of T. yunnanensis have the bulk of the elytra lighter than the base of the elytra and the pronotum. The new species is actually more similar to the Mediterranean species T. destruens, which differs in geographical distribution and in having the punctures of interstria 2 dense on the declivity and light-colored antennae. Species of Tomicus are of general concern to foresters because of their impact on conifer growth, but good illustrations for many species are lacking. We here provide a detailed key to all seven species of the genus (T. minor, T. piniperda, T. destruens, T. brevipilosus, T. yunnanensis and the virtually unknown T. puellus and T. pilifer) as well as diagnostic photographs and drawings. We summarize the biological differences between the new species and T. piniperda and recommend improved communication between taxonomists and forest entomologists, as avoidable taxonomic confusion such as that of T. yunnanensis and T. destruens with T. piniperda hinders the combatting of outbreaks of forest insects.

ROLE OF PLANT ENEMIES IN THE FORESTRY OF INDIGENOUS VS. NONINDIGENOUS PINES

Plantations of rapidly growing trees are becoming increasingly common because the high productivity can enhance local economies, support improvements in educational systems, and generally improve the quality of life in rural communities. Landowners frequently choose to plant nonindigenous species; one rationalization has been that silvicultural productivity is enhanced when trees are separated from their native herbivores and pathogens. The expectation of enemy reduction in nonindigenous species has theoretical and empirical support from studies of the enemy release hypothesis (ERH) in the context of invasion ecology, but its relevance to forestry has not been evaluated. We evaluated ERH in the productive forests of Galicia, Spain, where there has been a profusion of pine plantations, some with the indigenous Pinus pinaster, but increasingly with the nonindigenous P. radiata. Here, one of the most important pests of pines is the indigenous bark beetle, Tomicus piniperda. In support of ERH, attacks by T. piniperda were more than twice as great in stands of P. pinaster compared to P. radiata. This differential held across a range of tree ages and beetle abundance. However, this extension of ERH to forestry failed in the broader sense because beetle attacks, although fewer on P. radiata, reduced productivity of P. radiata more than that of P. pinaster (probably because more photosynthetic tissue is lost per beetle attack in P. radiata). Productivity of the nonindigenous pine was further reduced by the pathogen, Sphaeropsis sapinea, which infected up to 28% of P. radiata but was absent in P. pinaster. This was consistent with the forestry axiom (antithetical to ERH) that trees planted "off-site" are more susceptible to pathogens. Fungal infections were positively correlated with beetle attacks; apparently T. piniperda facilitates S. sapinea infections by creating wounds and by carrying fungal propagules. A globally important component in the diminution of indigenous flora has been the deliberate large-scale propagation of nonnative trees for silviculture. At least for Pinus forestry in Spain, reduced losses to pests did not rationalize the planting of nonindigenous trees. There would be value in further exploration of relations between invasion ecology and the forestry of nonindigenous trees.

Do restoration fellings in protected forests increase the risk of bark beetle damages in adjacent forests? A case study from Fennoscandian boreal forest

Gap fellings are used to promote multi-cohort structures and to restore other natural forest structures and processes in protected areas that have been altered by anthropogenic activities. Gaps and felled trees may also provide breeding material for species that in high numbers can cause significant tree mortality, growth reduction and consequent economic losses in surrounding production forests. In this study, the effect of restoration gap fellings on feeding intensity of Tomicus spp. (pine shoot beetles) was evaluated by counting fallen pine shoots at different distances from gaps in a protected area in eastern Finland. Gap fellings had a clear effect on the feeding intensity of the beetles. The average density of fallen shoots m −2 was 17 within a 10-m distance from gaps but decreased rapidly to around 4 at the distance of 50 m and beyond. The distance decay in shoot feeding is described well by the negative exponential models. Our results suggest that gap fellings have only a localized effect on shoot feeding by Tomicus in the forests surrounding the restoration gaps. In practical restoration, a buffer zone of 100–200 m around the gap fellings, as implemented here, is enough to minimize economically significant growth reduction in surrounding production forests. As shown in this study, restoration of natural forest structures and dynamics to protect biodiversity is not necessarily in conflict with forest hygiene objectives in production forests.