Innovative methods of non-destructive evaluation of log quality

For the sustainability of an important renewable resource, such as wood, it is important to significantly increase the efficiency of its processing. A large part of this raw material ends up in the wood processing industry, where it is used for the production of pulp, paper, construction and furniture timber, floors and others. Therefore, it is very important to gain the knowledge needed for optimal valuation of raw wood material, through quality detection and classification into quality classes. There are many defectoscopic methods working on different physical principles. The most familiar of these methods are semi-destructive and non-destructive, as they do not cause damage to the tree or wood during assessment. The aim of this article is to describe, assess and compare known semi-destructive and non-destructive methods for the assessment of wood properties. This article describes basic visual inspection, basic semi-destructive methods (Pilodyn, Resistograph) and advanced semi-destructive methods (SilviScan®, DiscBot®) as well. Non-destructive methods use mostly acoustic wave motion (acoustic, ultrasonic), high-frequency waves (using georadar, microwave) and methods based on visual evaluation (image, laser). At last, there are X–ray methods with the latest technology using three-dimensional (3D) computed tomography (CT). The implementation of modern non-destructive methods is of great importance for the application of principles of Industry 4.0, where these methods provide collecting of data on the material properties, in its entire production flow of log processing.

Flight performance of Monochamus sartor and Monochamus sutor, potential vectors of the pine wood nematode

Flight performance of Monochamus sartor and Monochamus sutor, two potential vectors of the pine wood nematode, Bursaphelenchus xylophilus was evaluated in laboratory flight mill tests. Beetles emerging from logs infested in the laboratory and incubated under outdoor conditions as well as field collected beetles were used. The maximum distance flown by M. sartor in a single flight was 3,136.7 m. Mean distances (per beetle) per flight ranged from 694.6 m in females to 872.5 m in males for M. sartor. In 75% of all individual flights M. sartor flew less than 1 km; only 3.7% flew distances longer than 2 km. The mean cumulative distance travelled by M. sartor beetles throughout their lifespan was 7.5 km. The smaller M. sutor beetles flew faster and longer distances. The maximum distance per flight was 5,556.5 m; mean distances ranged from 1,653.6 m in females to 1178.3 m in males. The number of available laboratory reared beetles was too low for quantification of lifetime flight capacity for M. sutor. The findings are compared to published data from Monochamus galloprovincialis recorded on the same type of flight mill as well as to field data from mark-release-recapture studies. The high flight capacity of Monochamus beetles illustrates the importance of considering dispersal of the vectors when planning control measures against the pine wood nematode.

Extremely low infection levels of pathogens and nematodes in Trypodendron spp. (Coleoptera: Curculionidae)

The striped ambrosia beetles Trypodendron lineatum and T. domesticum are timber forest pests in the Palearctic region and North America. Because only a few pathogens are known for Trypodendron species, the aim of this work was to determine the spectrum of pathogen species of T. lineatum, T. laeve, and T. domesticum. Trypodendron species were collected in pheromone traps at nine localities in the Czech Republic, five localities in Poland, and one locality in Austria. In total, 2,439 T. lineatum, 171 T. domesticum, and 17 T. laeve beetles were dissected and examined. Infection was found in only two of the 17 specimens of T. laeve and in only two of the 171 specimens of T. domesticum; in all four cases, the parasites were nematodes. Parasitisation of T. lineatum by nematodes was found in T. lineatum at eight localities with a mean (± SE) parasitisation level of 8.1 ± 4.7%. A Chytridiopsis sp. was detected in cells of the midgut epithelium of one T. lineatum specimen, and Gregarina sp. was detected in the midgut lumen of two T. lineatum specimens; no other pathogens were found in T. lineatum. The low infection rates and the tendency for infection by nematodes can be explained by the monogamy of Trypodendron spp. and their feeding on fungi in short galleries that are not connected to the galleries of conspecifics.

Review of Lepidoptera with trophic relationships to Picea abies (L.) in the conditions of Czechia

Trophic relationships of Lepidoptera (Insecta) occurring in the territory of Czechia to the Norway spruce (Picea abies L.) was evaluated on the basis of the excerption and critical evaluation of literature. Each species was classified into the following categories – spruce as the host plant, regular development on spruce, narrow trophic relationship, indirect relationship and episodical occurrence. The particular taxa were also characterized according to their distribution and the form of larval life was specified. The development on spruce was documented in 96 species of Lepidoptera, which represented less than 3% of taxa belonging to this group and being reported from Czechia. Of that, spruce was a common host plant for 67 species, 23 species were polyphagous and might develop on spruce, and 6 species belonged to soil species damaging spruce roots, mainly in forest nurseries. Among the species of Lepidoptera, which regularly develop on spruce in the Czech conditions, 55 species were classified. As narrow specialists with special trophic relationship to spruce, 33 taxa could be considered. There were 15 spruce species with forestry importance, which were able to outbreak their populations regularly or irregularly. Among spruce species it was possible to classify 16 taxa as rare. The provided information on Lepidoptera with trophic relationship to spruce is applicable also for other Central European areas. Besides the species with importance for forest pest management, also rare taxa, which can become endangered by climate change or by forest management, were indicated.

Defence reactions of mature Norway spruce (Picea abies) before and after inoculation of the blue-stain fungus Endoconidiophora polonica in a drought stress experiment

We performed an inoculation experiment using the blue-stain fungus Endoconidiophora polonica at the Rosalia Roof study site, which was set up to study drought effects on Norway spruce susceptibility to attacks by the European spruce bark beetle Ips typographus. Tree resistance parameters such as resin flow rate and extent of hypersensitive wound reaction in the phloem were investigated prior to and after fungal infection. Sample trees with different drought treatments (trees fully covered or semi-covered by roofs, control trees) were inoculated with E. polonica in July 2014. In order to check for areas of phloem necrosis, the outer bark around the inoculation holes was scratched off 6 weeks later. We recorded the amount of resin exudation within 12 hours overnight in August and September 2013 and 2014. Although wound reaction zones did not differ in size between tree collectives of the various treatments, fully covered trees tended to exhibit larger necrotic areas compared to control trees. The least water supplied trees showed lowest resin flow rates prior to fungal inoculation, but were the only group to show significantly enhanced resin flow five weeks after the evaluation of defence reactions. Our results agree with earlier findings that wounding and few fungal inoculations can increase tree resistance in the medium term given not too severe water stress. Further investigations will clarify how water stress affects the availability of non-structural carbohydrates for secondary metabolism, when depletion of resources eventually occurs, and at which point trees are most susceptible to bark beetle attack.

Foraging strategy and food preference of Formica polyctena ants in different habitats and possibilities for their use in forest protection

Food availability is an important factor influencing the lives of ant colonies. Wood ants consume protein-rich and sugary foods. Protein-rich food is comprised primarily of insects, a considerable proportion of which the ants acquire by direct predation. They therefore play an important function in biological protection of forests. The objective of our study was to determine if workers activity is dependent on habitat type, size of the nest, bait size and food type (sugar, protein). We selected 23 nests in a spruce forest and placed food baits of various sizes and types near each nest. The results obtained show that the number of individuals on the baits was substantially higher in clearings than within mature forest. The number of worker ants recorded on the baits was slightly higher for larger nests. Bait size and type had no influence on the number of workers present. Because wood ants do not focus solely on food of a certain size or quality, they can effectively decrease the abundance of forest pests.

Infection levels of pathogens in the European spruce bark beetle Ips typographus (Coleoptera: Curculionidae) at managed and unmanaged forest locations: a meta-data analysis

Forest management greatly affects the population density of the European spruce bark beetle, Ips typographus. In this study, a meta-analysis was used to determine whether infection levels of pathogens of I. typographus differ between managed and unmanaged spruce stands. The analysis used data from 10 publications and a total of 61 locations. The results indicated that infection levels of the most common pathogens (ItEPV, Gregarina typographi, and Mattesia schwenkei) are higher in unmanaged than in managed locations. The only exception is the microsporidium Chytridiopsis typographi, which is more common in managed than in unmanaged locations. Our meta-analysis indicates that pathogen levels are generally higher in unmanaged than in managed locations.

Effectiveness of pheromone traps for the European spruce bark beetle: a comparative study of four commercial products and two new models

Six types of pheromone traps were tested between 2012 and 2014 in the High Tatra Mountains, northern Slovakia. Traps were baited with lures for attracting the European spruce bark beetle (Ips typographusL.) (Coleoptera: Curculionidae, Scolytinae). Among the tested traps, four types are commercial products; Theysohn (T-trap), Ecotrap (E-trap), Lindgren funnel trap (L-trap), BEKA trap (B-trap) and two are our newly developed models; Funnel trap (P-trap) and Cross trap (K-trap). The traps were set up on ten selected sites and tested during three growing seasons (2012, 2013 and 2014). The newly developed models were compared to the commercially available models for trapping efficiency of target pest, easy to use and impact on non-target insect species. We found that the best commercially available model is the L-trap, however the bottom of L-trap is considered too shallow resulting in an accumulation of rainwater that increases the traps attractiveness for Silphids. In our experiment, the newly developed models; P-trap and K-trap performed better compared to commercially used models. P-trap caught 28% moreI. typographusand K-trap caught 57% more beetles compared to T-trap in 2014. There are additional advantages of the newly developed traps such as easy handling, good rainwater drainage, higher collection container volume, and scale marking within the collection container. The results of this study have encouraged us to patent P-trap and K-trap as utility models.

Ultrasonic technique for evaluation of initial stadium of wood degradation in exterior conditions without ground contact

The experiment evaluate the possibility of using non-destructive measure techniques of the mechanical properties of wood using ultrasonic to determine the initial stages of degradation by biotic and abiotic factors in the outdoors without ground contact. Nine tree species were tested: spruce, pine, Douglas fir, larch, oak, black locust, maple, poplar and alder. Test specimens were exposed to the exterior according to EN 927-3, Prague-Suchdol in the Czech Republic. Measuring changes in velocity of ultrasonic using the apparatus Ultrasonic Timer and moisture content change were measured after 1, 2, 3, 4 and 6 months. Certain ways of detecting the initial stages of damage have been demonstrated to trees oak, larch and spruce. The initial stages of damage by molds at non-durable maple, alder and poplar had not a clear impact on the decrease in the speed of ultrasonic, as well as hairline surface cracks at the Douglas fir.

Evaluation of winter food quality and its variability for red deer in forest environment: overwintering enclosures vs. free-ranging areas

Populations of European ungulates have grown substantially over recent decades, resulting in considerable environmental and socio-economic impacts. Availability and quality of natural and supplemental food sources are among the main factors driving their population dynamics. Detailed knowledge of food quality of management-targeted species is therefore of primary importance for their successful management. The main aim of this study was to evaluate winter food quality and its variability for an important ungulate species in the Czech Republic - i.e. red deer, using faecal indices (faecal nitrogen, faecal acid detergent fibre, faecal neutral detergent fibre) and near infrared reflectance spectroscopy. We compared food quality for red deer and its possible differences between overwintering enclosures (i.e. fenced areas where red deer spend harsh winter conditions) and neighbouring unfenced free-ranging areas within two study areas. The results obtained showed that winter food quality and its variability for red deer are of different quality and variability in the overwintering enclosure and neighbouring free-ranging area. The observed differences in concentrations and amounts of variation of faecal indices are most probably related to animal densities at individual study areas. Wildlife managers should therefore keep animals in overwintering enclosures at moderate densities and to provide high quality forage to all individuals in order to balance nutrition of both the individuals inside and outside the enclosures. Nevertheless, further studies are needed in order to provide deeper knowledge on red deer food quality and its variability in space and time.