Fagus Silvatica Research Articles

Pull-compression tests on glued-in metric thread rods parallel to grain in glulam and laminated veneer lumber of different timber species

Ongoing development of timber and timber products made from European hardwoods like ash and beech influences the selection of acceptable methods for connecting these elements and thus demands validation and application of current design methods for softwood and glulam. For the last 20 years, despite many national and international research projects and practical applications of glued-in rods in timber structures, there is still no universal standard with respect to their design. The use of adhesives available for bonding rods and timber is limited to softwood. This work shows the performance of different timber species Norway spruce (Picea abies Karst.), European ash (Fraxinus excelsior L.) and European beech (Fagus silvatica L.) and engineered timber products (laminated veneer lumber made of Norway spruce and European beech) based on comprehensive pull-compression tests of glued-in rods. For characterizing the elastic and elastic-plastic behavior, failure loads as well as stiffness and ductility were considered whereby the rod diameter and anchorage length were maintained constant. The aim of the research was to show that glued-in rods cannot only be used in softwoods and glulam members but also in hardwoods and in wood-based products such as LVL.

Wybrane zagadnienia z morfogenezy liści drzew. II. Występowanie młodocianych form liści w koronach drzew buka zwyczajnego (Fagus silvatica L.) [Studies on the mohprogenesis of tree-leaves. II. The occurrence of juvenile forms of leaves in the crowns of beech trees (Fagus silvatica L.)

It was fairly often observed that <em>Fagus silvatica</em> L. leafed twice during one vegetational season. This secondary growth occurred on all trees, when the first leaves underwent destruction, e.g. in consequence of late spring frost. The leaves of secondary growth differed pronouncedly from normally developed ones by their shape and irregular nervation and were similar to the juvenile leaves of one-year-old seedlings of beech. Observations of leaf buds showed that the nerves appeared in leaf-primordia of <em>Fagus silvatica</em> as late as the latter part of July and if the secondary leaves developed at the end of July, they were normal in shape and bad regular nervation. Leaf-primordia compelled to an earlier development gave leaves of different form and irregular nervation.

The Influence of Adhesion Temperature to the Shear Strength of Width Glued Wooden Elements

This paper examined the effect of temperature of pressing on the strength of width glued elements during the process of production of solid wood panels. It has been used the polyvinylacetate D3 adhesive and solid beech wood (Fagus silvatica). Time of pressing has been determinate separately for each level of temperature of bonding, which amounted to (30o, 40°, 50°, 60°, 70o C). For each level has been formed 20 samples in order to determinate the value of the shear strength of bonded joint. The results were processed using the Student's t-test. This research showed that with increasing the temperature and pressing time increases the shear strength of the bonded joint, but non-linear.

Observation of changes of cambial domain patterns on the basis of primary ray development in Fagus silvatica L.

The high multiseriate primary rays that occur in young stems of <i>Fagus silvatica</i> L. undergo splitting during cambium development. Segments of the split primary rays remain close to each other and form characteristic strands. Within these strands, sections can be observed in which the rays are split in the same direction, either in configuration Z or S. The configuration of other cambial cellular events neighboring the primary rays under consideration is in agreement with the configuration of the splitting of these rays. The arrangement of the rays on the surface of the wood after debarking a young stem makes it possible to decipher the domain pattern on a surface of any given size. As the stem segment ages, the borders between domains migrate and new borders are formed, changing their course from longitudinal to transverse.

Bursaphelenchus fagi sp. n. (Nematoda: Parasitaphelenchidae), an insect-pathogenic nematode in the Malpighian tubules of the bark beetle, Taphrorychus bicolor (Herbst.) (Coleoptera: Curculionidae, Scolytinae), in European beech, Fagus silvatica L.

Bursaphelenchus fagisp. n. is described from the bark of European beech,Fagus silvatica. All propagative stages of the nematode are numerous in larval galleries of the beech bark beetle,Taphrorychus bicolor, while dauer juveniles aggregate in Malpighian tubules of adult beetles. The new species is characterised by the body length of 871 (763-1110) μm in female and 852 (718-992) μm in male, very slender body (a = 56.8 (50.4-67.1) and 64.5 (56.5-73.8) in female and male, respectively), and spicules 15.2 (14.0-17.0) μm long. The extended anterior vulval lip in female, lateral fields with four incisures, and number (7) and arrangement of male caudal papillae may indicate thatB. fagisp. n. is closely related to thexylophilusgroup. It differs from this group by the relatively small, claw-like spicules with narrow capitulum, indistinct condylus in almost continuous line with dorsal lamina, and lack of distinct cucullus at the spicule tip. The close relation ofB. fagisp. n. with thexylophilusgroup has been confirmed by DNA sequencing and phylogenetic analysis of the 28S rDNA region.Bursaphelenchus fagisp. n. most closely resemblesB. tokyoensisandB. idius, but can be separated by differences in the arrangement of the male caudal papillae, a unique feature for each species. The taxonomic separation of the new species is also confirmed by the unique molecular profile of the ITS region (ITS-RFLP). The mass presence of dauer juveniles ofB. fagisp. n. in Malpighian tubules of adultT. bicolorleads to degradation of the tubule cellular epithelium and local expansion of its basement membrane. These changes clearly indicate direct pathogenicity of the nematode to its vector insect. In laboratory rearing,B. fagisp. n. can grow and reproduce onBotryotinia fuckelianacultures.

Transformation of the domain pattern in the development of Fagus silvatica L. cambium

The domain pattern of cambium during the first year of its function in <i>Fagus silvatica</i> L. resembles a checkerboard. The longitudinal line along the leaf trace, its corresponding line on the opposite side of the internode and nodes comprise the domain borders. Starting from the formation of the first annual ring, this checkerboard pattern begins to undergo gradual transformation. A transitional domain pattern appears during the first few years; in each internode, due to the alternate disappearance of Z and S domains, a fragmentary domain of one type and an expanded domain of the opposite type occur in pairs. After further transformations, a regular pattern of transverse bands of domains moving along the stem appear on older stems (over ten years-old). This pattern is commonly found in other studied species of trees.

Comparative adhesion analysis at glue joints in European beech and Norway spruce wood by means of nanoindentation

To gain a better insight into the delamination behaviour of glue joints in hardwood, the adhesion at the cell wall level was investigated. By the use of nanoindentation techniques, the adhesion, hardness and Young's modulus of adhesively bonded European beech wood (Fagus silvatica L.) was analysed. To highlight differences between soft- and hardwood adherends, Norway spruce wood (Picea abies KARST.) was also investigated. One-component polyurethane (PUR) and phenol resorcinol formaldehyde resin (PRF) were used for bonding. Untreated and aged samples (artificially and naturally weathered) were analysed and compared to silylated samples as reference, assuming the silylation reduces the adhesion to a minimum. From the gathered results it can be concluded that artificial ageing has the same effect as natural weathering on, both, adhesion and the properties of the single components of a bond. In beech wood, weathering increases the adhesion of PUR significantly. For PUR in spruce wood, the adhesion is not affected by any treatment. Tensile shear tests signified a reduced adhesion in all silylated samples. Additionally, the stiffness and hardness of both adhesives were found to be reduced by approximately 10%. As a consequence, the applied silylation is not considered as adequate treatment for reference samples.

Natural regeneration of shade-tolerant Abies alba Mill. in gradients of stand species compositions: Limitation by seed availability or safe microsites?

This paper analyses the effect of selected site and stand variables on the natural regeneration of the late-successional species Abies alba Mill. in a sequence of stands with increasing partition of three other tree species: light-demanding early-successional Pinus sylvestris (L.), moderately shade-tolerant Picea abies (L. Karst.), and shade-tolerant late-successional Fagus silvatica (L.). The data used originated from inventories carried out in publicly owned forests in southern Poland on a total of 2262 stands in a 30,700ha area. First, the effect of geographic location, altitude, slope, aspect, site trophism, stand age, stand volume and proportion of admixed species on the occurrence of A. alba regeneration was analysed using generalised linear models (GLZ). The empirical associations derived from these models were then compared with the expected outcomes for two scenarios of seedling over-dispersion given a decreasing number of trees producing seeds and a neutral effect of admixed species. The highest regeneration coverage was found in pure A. alba stands. In the mixed stands, regeneration coverage decreased with a decreasing proportion of A. alba, although at a lower rate than might be expected given a neutral effect of admixed species. The survival rate modelled in close to mono-specific stands (i.e., those with 90%) of P. abies, F. sylvatica and P. sylvestris was 3.0–8.5 times higher than in pure A. alba stands. Nevertheless, the reduced seed availability resulting from a lower number of seed producers in mixed stands might not be fully balanced by more advantageous microsite conditions. In stands with a high percentage of the early-successional species P. sylvestris, regenerative conditions were no more advantageous than in stands with a high percentage of late-successional species. The higher modelled survival rate of A. alba regeneration in stands of late-successional P. abies and F. sylvatica than in stands of con-specific trees may be viewed as an increase-when-rare mechanism. The question remains, however, of whether it is an intrinsically anthropogenic mechanism (e.g., increased herbivory pressure) or a natural mechanism capable of maintaining the mixed species composition of climax communities undisturbed by man.

Hydrological effects of Norway spruce and European beech on snow cover in a mid-mountain region of the Polana mts., Slovakia / Hydrologický vplyv smreka obyčajného a buka lesného na snehovú pokrývku v stredohorských polohách pohoria poľana na slovensku

The paper evaluates the results of a 6-year-monitoring of the eco-hydrological influence of Norway spruce (Picea abies (L.) Karst.) and European beech (Fagus silvatica L.) forest stands on the hydro-physical properties of snow cover. The experiment was carried out in the artificially regenerated 20-25-year-old forest stands approaching the pole timber stage in the middle mountain region of the Polana Mts. - Biosphere reserve situated at about 600 m a.s.l. during the period of maximum snow supply in winters of years 2004 - -2009. Forest canopy plays a decisive role at both the snow cover duration and spring snow melting and runoff generation. A spruce stand is the poorest of snow at the beginning of winter. High interception of spruce canopy hampers the throughfall of snow to soil. During the same period, the soil surface of a beech stand accumulates greater amount of snow. However, a spruce stand accumulates snow by creating snow heaps during the periods of maximum snow cumulation and stand´s microclimate slows down snow melting. These processes are in detail discussed in the paper. The forest stands of the whole biosphere reserve slow down to a significant extent both the snow cover melting and the spring runoff of the whole watershed.

Shape stability of laminated veneer products – An experimental study of the influence on distortion of some material and process parameters

A shortcoming of the laminated bending process is that the products may become distorted after moulding and during use. In this study, we have examined the influence of different UF-adhesive systems, adhesive distribution, and veneer properties such as species, moisture content, and fibre orientation. Two different species were studied: beech (Fagus silvatica L.) and birch (Betula pubescens Ehrh.). Distortion was determined directly after moulding and after storage in a changing relative humidity. The aim of the work was to study how the above-mentioned material and process parameters influence the distortion. The results show that the material and process parameters and the storage in a changing relative humidity had a clear impact on distortion. Fibre orientation, differences in moisture content between veneers, and the moisture gradient in the final product are identified in this study as being the most important parameters influencing the distortion and shape stability of laminated veneer products.

Cutting force variability as a consequence of exchangeable cleavage fracture and compressive breakdown of wood tissue

In the present study, the conditions of chip propagation or fracture in orthogonal oblique cutting of beech wood (Fagus silvatica) in the 90°–0° direction for a type-I chip has been investigated. The force required for orthogonal wood cutting is pronouncedly variable, which is the consequence of exchangeable different ways of material breakdown. The chip formation process is discontinuous because of interrupted splitting of the material in front of the cutting tool. A 10-mm-thick specimen was cut at a rake angle of 31° and 42° with chip thicknesses ranging from 0.1 to 0.3 mm. The chip segment length increased with the chip thickness. A chip of varying length and thickness was modelled using the finite element method. For each case, the bending or compressive stress in the chip and the stress intensity factor at the crack tip was calculated. The segment length of the chip can be calculated by taking into account the condition that a crack propagates when the stress intensity factor KI at the crack tip equals the critical stress intensity factor KIC, and the bending or compressive stress σx in the chip is smaller than the strength σu. Good agreement between the calculated and the measured values was observed. The chip segment length can change considerably already with small changes in the bending strength and critical stress intensity factor. This large sensitivity is also confirmed by the fluctuation of the measured chip segment lengths by as much as 400%.

Gluability of thermally modified beech (Fagus silvatica L.) and birch (Betula pubescens Ehrh.) wood

One of the main disadvantages of wood is hygroscopicity resulting from its polar character. The sorption–desorption of water causes unwanted swelling and shrinkage in wood. Thermal modification substantially reduces this inconvenient feature. Unfortunately, the same chemical changes that reduce water sorption alter the polar character of the material and result in poorer wetting of thermally treated wood by waterborne adhesives. Gluability of thermally modified beech (Fagus silvatica L.) and birch (Betula pubescens Ehrh.) wood with two commercial amino resins, melamine–urea–formaldehyde (MUF) and melamine–formaldehyde (MF), and a two-component polyurethane (PUR) adhesive was investigated. Both wood species were modified according to two temperature regimes: 160°C and 190°C. Shear strengths of the joints were then determined according to EN 205:2003 standard. The results showed that thermally modified beech and birch wood can be effectively glued not only with commercially available PUR adhesives, but also with aqueous MF and MUF resins. The resultant shear strengths of the joints were limited by the strength of the thermally modified substrate.

Effects of root trenching of overstorey Norway spruce (Picea abies) on growth and biomass of underplanted beech (Fagus sylvatica) and Douglas fir (Pseudotsuga menziesii) saplings

In Central Europe, the conversion of pure Norway spruce stands (Picea abies [L.] Karst.) into mixed stands with beech (Fagus silvatica L.) and other species like e.g. Douglas fir (Pseudotsuga menziesii [Mirb.] Franco) is accomplished mainly by underplanting of seedlings beneath the canopy of overstorey spruce trees after partial cutting treatments what means exposure to shade and below-ground root competition by the overstorey to the seedlings. Particularly about the second factor, our knowledge is limited. Therefore, we carried out a below-ground competition exclusion experiment by root trenching and investigated the effects on soil resources, growth, and biomass partitioning of underplanted beech and Douglas fir saplings under target diameter and strip cutting treatments. The exclusion of overstorey root competition by trenching increased the soil water potential in the second year that had a fairly dry growing season and led to significantly higher foliar concentrations of most nutrients, particularly in Douglas fir, indicating an amended nutrient supply. Both improvements were accompanied by an increase in length and diameter increment of the underplanted saplings, appearing in both species only after having surpassed a species-specific threshold light value (Douglas fir 16% of above canopy radiation, beech 22%). We also found significant interactions between trenching and light for specific fine root length and further biomass and morphological parameters. Judged by the much steeper increase in height and diameter growth with increasing light after release from below-ground competition, Douglas fir saplings appeared to be more sensitive to root competition than beech saplings what conforms to older findings for beech. According to our results, a strip cutting seems to be more appropriate than a target diameter cutting treatment to replace a pure spruce stand by a mixed stand with beech and Douglas fir.

Comparison of the severity of selection among beech leaves prior to egg-laying between a leaf-mining and two gall-inducing insects

Quantitative behavioural traits associated with egg-laying, such as the level of selectivity for host-supports and the size of egg clutches, are generally thought to be of great importance for the subsequent survival and development of offspring. These quantitative traits, however, are often difficult to assess reliably by direct observation in the field. This is particularly the case when the insects are very tiny, which is the case for most galling and leaf mining insects. However, a new approach, the Melba procedure, allows the indirect inference of these quantitative traits, using easily recorded field-data only. Application of this diagnostic procedure to a large series of samples of beech leaves (Fagus silvatica), harbouring either a leaf miner, Phyllonorycter maestingella (Lepidoptera: Gracillariidae) or one or the other of two galling insects, Mikiola fagi or Hartigiola annulipes (Diptera: Cecidomyiidae) indicates that the leaf miner differs significantly from the two species of galling insect in term of combined values of host-acceptance ratio and average clutch-size, while the two gall-inducing species remain substantially undistinguishable from each other according to these traits. Thus, the galling insects (i) show stronger selectivity for a host than does the miner at any given average clutch-size and (ii) show larger average clutch-size at any given level of selectivity. That is, for at least these three species, the galling insects show a greater level of selectivity when choosing leaves to oviposit on but, then, tend to lay larger egg-clutches. These differences may be due (i) to the gall-inducing process requiring far more of leaf tissues than being simply palatable, which makes it likely that galling species will be more selective in their choice of leaves than leaf miners and (ii) to the capacity of galls to become nutrient sinks, which may help explain why the galling insects laid larger egg clutches. However, whether these trends can be regarded as general rather specific to this particular case, depends on the outcome of future studies on other groups of insects with similar life histories.

A one-dimensional model of water flow in soil-plant systems based on plant architecture

The estimation of root water uptake and water flow in plants is crucial to quantify transpiration and hence the water exchange between land surface and atmosphere. In particular the soil water extraction by plant roots which provides the water supply of plants is a highly dynamic and non-linear process interacting with soil transport processes that are mainly determined by the natural soil variability at different scales. To better consider this root-soil interaction we extended and further developed a finite element tree hydro-dynamics model based on the one-dimensional (1D) porous media equation. This is achieved by including in addition to the explicit three-dimensional (3D) architectural representation of the tree crown a corresponding 3D characterisation of the root system. This 1D xylem water flow model was then coupled to a soil water flow model derived also from the 1D porous media equation. We apply the new model to conduct sensitivity analysis of root water uptake and transpiration dynamics and compare the results to simulation results obtained by using a 3D model of soil water flow and root water uptake. Based on data from lysimeter experiments with young European beech trees (Fagus silvatica L.) is shown, that the model is able to correctly describe transpiration and soil water flow. In conclusion, compared to a fully 3D model the 1D porous media approach provides a computationally efficient alternative, able to reproduce the main mechanisms of plant hydro-dynamics including root water uptake from soil.

Insights into fry-drying process of wood through a simplified approach of heat and mass transport phenomena

Fry-drying process of wood involves intense water vaporization. The pressure at a sample core increases over 250 kPa. Under such pressure conditions, vapour transport driven by Darcy's law should be considered as the prevailing phenomenon in a simplified heat and mass transport model. The latter was developed in the absence of mechanical deformation and oil penetration, in a 2D rectangular geometry and solved numerically with commercial finite element software. Free and bound water were distinguished in the energy equation. Despite the directions of vapour flux being orthogonal to the simulation plane, the use of only two adjusted permeabilities (9 × 10 −15 and 9 × 10 −16 m 2) allowed the characterisation of a large amount of wood, regardless of sample size and permeability variability. The model was experimentally validated with local pressure and temperature measurements at the core, temperature alone at three locations and with overall water loss. Beech ( Fagus silvatica), oak ( Quercus pedonculae) and maritime pine ( Pinus pinaster) were considered at both laboratory (0.3 m in length) and industrial (2 m in length) scales in the temperature range from 103 to 180 °C. Evidence of mechanical degrade or cracks was observed at 180 °C due to the sudden decrease in water boiling point and by fluctuations in temperature kinetics.

Changes in Pelagic Bacteria Communities Due to Leaf Litter Addition

In many limnetic systems, the input of allochthonous organic matter, e.g., leaf litter, is a substantial source of dissolved organic carbon (DOC) for pelagic bacteria, especially in fall and winter when autochthonous DOC production is low. However, relatively little is known about community changes of pelagic lake bacteria due to leaf litter input which includes both the release of leaf leachates and microorganisms from the leaf litter into the surrounding water. Therefore, we have experimentally studied the effects of different types of leaf litter (Betula pendula, Fagus silvatica, and Pinus silvestris) on the pelagic bacterial community composition by adding leaves to different treatments of epilimnic water samples (unfiltered, 0.2 µm and 5.0 µm-pre-filtered) from humic Lake Grosse Fuchskuhle (Northeastern Germany). The addition of leaf litter led to a significant increase in DOC concentration in lake water, and each leaf litter type produced significantly different amounts of DOC (p = <0.001) as well as of specific DOC fractions (p = <0.001), except of polysaccharides. DGGE banding patterns varied over time, between types of leaf litter, and among treatments. Bacteria belonging to known bacterial phylotypes in the southwest basin of Lake Grosse Fuchskuhle were frequently found and even persisted after leaf litter additions. Upon leaf litter addition, α-proteobacteria (Azospirillum, Novosphingobium, and Sphingopyxis) as well as β-proteobacteria (Curvibacter and Polynucleobacter) were enriched. Our results indicate that supply of leaf litter DOM shifted the bacterial community in the surrounding water towards specific phylotypes including species capable of assimilating the more recalcitrant DOC pools. Statistical analyses, however, show that DGGE banding patterns are not only affected by DOC pools but also by treatment. This indicates that biological factors such as source community and grazing may be also important for shifts in bacterial community structure following leaf litter input into different lakes.

Minerals management in silvopastoral system of karst pasture

A survey of mountain pasture topsoil was undertaken first to set up field experiment in karst region on effects of applied P on minerals concentration in herbage. Content of SOM, C, N, CEC of soil and its base saturation are presented in the article. Great variability in depth, pH value and K level was found in soil. Low base saturation and high deficit of P was more common for all soil samples. Six different plant species presenting a great portion of herbage available for grazing and browsing at different occasions during grazing season were sampled and analysed for macro- and some microminerals. Concentration of P was very low in perennial grasses (1.1 g P kg−1 of DM). In leaves of common hazel (Corylus avellana L.) and common beech (Fagus silvatica L.) the concentration of P was identical as in white clover (Trifolium repens L.) and the level was high enough to cover animal needs when intake of herbage was sufficient. Leaves of woody plants were high in Mn concentration, but still below the levels that reduced growth rate in lambs. Application of P fertilizer had only small effect on increase of P in herbage, but large one on decrease on concentration of Ca in herbage. There was not clear effect of added P on concentration of Zn, Mn, Fe and Cu. Higher yield of DM induced with added fertilizer had not have any dilution effect on concentration of those minor elements in herbage.

The resistance of surfaces treated with oils and waxes to the action of dry heat

Surface treatment of wood can be done with different coatings, and the choice of the appropriate system of processing depends on several factors, such as technological, aesthetic, economic and ecological. Raising awareness of the need to preserve the living and working environment has had a crucial impact on the increase in the use of natural materials for surface treatment of wood - oil and wax. The application of oils and waxes allows surface treated wood to keep the natural look, while protecting it from different influences, which can cause degradation and deterioration of the final product. The paper presents the results of testing the resistance of beech surface (Fagus silvatica L.) processed with linseed oil and beeswax to the action of dry heat. In order to compare the quality of surface treated with oil and/or wax, beech wood treated with 2K-polyurethane coating is taken as a reference of surface treatment of wood. Surfaces treated with beeswax are less resistant to dry heat than those treated with linseed oil, and both showed significantly less resistance than surface treated with 2K-polyurethane coating.

Sorption dynamics of N 2 and O 2 in carbon monoliths from spruce, beech and oak affected by activation

Three series of activated carbon monoliths have been prepared from logs of different trees (spruce ( Picea abies), beech ( Fagus silvatica), oak ( Quercus robur)) by pyrolization in nitrogen flow at 700 °C and then by steam activation at 900 °C for different duration of the conversion. The characterization of carbon skeleton in the samples was performed by small angle X-ray scattering (SAXS), atomic force microscopy (AFM) and scanning electronmicrography (SEM). The carbonized xylem retained the original tracheal structure of the wood. Biological diversity of wood precursors reflected in the nanometer range likewise than in micrometer range. The evolution of the microporosity has been followed by static gas adsorption (N 2 at −196 °C). The characterization of dynamic adsorption properties took advantage of the unique potentials of the frequency response (FR) technique (N 2 or O 2 at −78 °C). The obtained three-dimensional carbon frames exhibit low transport diffusional resistance due to the wide straight transport channels of micron size. All of the three wood types displayed nearly identical dependence of burn-off upon activation time, which in view of their similar cellulose composition, is not entirely unexpected. The shape of the isotherms indicates the presence of both micro and mesopores and the history of the activation is crucial for the developing porosity. The changes in the adsorption capacities of micropores reflect the differences of precursors and length of activation time. Compared to other methods FR technique seems to be more sensitive to distinguish such differences.