The results of research into utilizing grinded beech bark in order to substitute commonly used fillers in urea formaldehyde (UF) adhesive mixtures to bond plywood are presented in the present study. ...Four test groups of plywood with various adhesive mixtures were manufactured under laboratory conditions and used for experimentation. Plywood made using the same technology, with the common filler (technical flour), was used as a reference material. Three different concentrations of grinded beech bark were used. The thermal conductivity of the fillers used, viscosity and its time dependence, homogeneity and the dispersion performance of fillers were evaluated in the analysis of adhesive mixture. The time necessary for heating up the material during the pressing process was a further tested parameter. The produced plywood was analyzed in terms of its modulus of elasticity, bending strength, perpendicular tensile strength and free formaldehyde emissions. Following the research results, beech bark can be characterized as an ecologically friendly alternative to technical flour, shortening the time of pressing by up to 27%. At the same time, in terms of the statistics, the mechanical properties and stability of the material changed insignificantly, and the formaldehyde emissions reduced significantly, by up to 74%. The utilization of bark was in compliance with long-term sustainability, resulting in a decrease in the environmental impact of waste generated during the wood processing.
A foliar nematode, Litylenchus crenatae ssp. mccannii, is associated with beech leaf disease (BLD) symptoms. Information about the types of tissues parasitized and how nematode populations fluctuate ...in these tissues over time is needed to improve surveys as well as understand the nematodes role in BLD. During this study, the nematode was detected throughout the known range of BLD by researchers at both Canadian and US institutions using a modified pan method to extract nematodes. Monthly collections of symptomatic and asymptomatic leaves during the growing season (May–October), and leaves and buds between growing seasons (November–March), revealed that nematodes were present in all tissue types. Progressively larger numbers of nematodes were detected in symptomatic leaves from Ohio and Ontario, with the greatest detections at the end of the growing season. Smaller numbers of nematodes were detected in asymptomatic leaves from BLD‐infected trees, typically at the end of the growing season. The nematode was detected overwintering in buds and detached leaves. The discovery of small numbers of nematodes in detached leaves at one location before BLD was detected indicates that nematodes may have been present before disease symptoms were expressed. Other nematodes, Plectus and Aphelenchoides spp., were infrequently detected in small numbers. Our findings support the involvement of the nematode in BLD and indicate that symptoms develop only when certain requirements, such as infection of buds, are met. We also found that the nematode can be reliably detected in buds and leaves using the modified pan extraction method.
•Fagus orientalis was introduced to a northern German forest stand ca. 100 years ago.•F. orientalis hybridizes with autochthonous F. sylvatica in the introduced range.•Both species can act as pollen ...and seed parent.•The necessity and suitability for assisted gene flow management should carefully be evaluated.
Fagus sylvatica L., one of the most common Central European deciduous tree species, is one of the species globally suffering from changing and stressful environmental conditions. It has shown symptoms of crown damage, a reduction in growth and increased mortality following recent severe droughts. Fagus orientalis Lipsky, a closely related species with higher drought tolerance, originates from southeastern Europe, Turkey, the Greater Caucasus region, and the Hyrcanian forest. For Germany, F. orientalis has been proposed as an alternative to F. sylvatica by translocation of pre-adapted planting material as a tool to mitigate negative effects of climate change in certain locations. This approach can be beneficial but might also harbor risks.
We studied admixtures between the two beech species and the direction of gene flow, taking advantage of F. orientalis trees planted over 100 years ago in the forest district of Memsen, Germany. Additionally, we used a range-wide dataset of F. sylvatica and F. orientalis provenances to determine the origin of the introduced trees. Using a combination of nuclear microsatellites and one chloroplast marker with species-specific variants, we showed that interspecific gene flow was going in both directions. In most cases, F. sylvatica was the pollen donor, likely due to its greater abundance and production of vast amounts of pollen. The planted trees from Memsen originated from the Greater Caucasus region and showed strong genetic divergence from German F. sylvatica populations, clearly differing in leaf morphological traits. In the future, the suitability of different provenances for the mitigation of climate change impacts should be carefully assessed by testing gene flow patterns as well as hybrid performance in additional stands and in comparison to F. sylvatica provenances from southern Europe.
•To determine the effects of beech leaf disease (BLD) on forests, a plot network was established in the Great Lakes region of North America.•Beech leaf disease is replacing beech bark disease (BBD) ...as the primary pest of beech adjacent to Lake Erie.•Forest structure and composition changes are expected as BLD and BBD advance.•To conserve beech, research, breeding, and active management are imperative.
Over the past century, beech bark disease has dramatically altered the composition and structure of stands containing American beech (Fagus grandifolia). Management of beech bark disease has focused on reducing beech thickets and identifying resistant trees in aftermath forests. Beech leaf disease is a recently detected invasive disease, now also affecting beech forests. In 2019, a plot network was established in central North America to examine the extent of beech leaf disease spread and the severity of effects on trees and forests. Here, data from this plot network was used to determine the extent to which American beech is exposed to beech leaf disease, beech scale (Cryptococcus fagisuga), and beech bark disease (C. fagisuga and Neonectria spp. complex) in forests surrounding the Great Lakes in southwestern Ontario, northeastern Ohio, western Pennsylvania, and western New York. Beech leaf disease and scale were found to be well established, not only among sites but also in the different canopy layers. Beech bark disease was present, but occurrence was low. Pest accumulation differed between overstory and sapling layers. Beech leaf disease was the primary pest of saplings while both beech leaf disease and beech scale dominated in the overstory. Forest composition was similar throughout the study range; American beech, sugar maple, red maple, and white ash were abundant and common in the sapling and seedling layer. Few invasive plants were evident among saplings and seedlings. Sugar maple and red maple will likely fill small canopy gaps following beech decline or mortality. Intervention should be considered in stands with potential for increasing tree diversity or promoting beech leaf disease-resistant American beech trees to the overstory. New strategies are needed for beech conservation along with research to determine the extent of beech leaf disease resistance in American beech.
In this review, the phytogeography and history of Japanese beech (Fagus crenata Blume and F. japonica Maxim.) forests are re‐examined in light of recent phytogeographical and palaeobotanical research ...advances. I explain the floristics and the climatic and geological contrasts between Japanese beech forests on the Sea of Japan side and the Pacific side of the Japanese archipelago. We also review recent studies on the origin of dwarf evergreen shrub species occurring along the Sea of Japan. The old scenario that these dwarf evergreen shrub species diverged directly from counterpart species occurring on the Pacific coast of Japan is no longer supported. We propose more intricate speciation processes, including phylogenetic relations to extant Chinese species and inter‐species hybridization. We also review the results of recent palaeobotanical studies of forests on the Japanese islands in the Quaternary. The long persistence of beech forests through glacial/interglacial cycles of the Quaternary—with repeated spread and contraction of the geographical range—is confirmed. In addition, we briefly explain the phytosociological classification system of the Japanese beech forest and the geographical ranges of each vegetation type. We review studies of the geographic distribution of F. crenata and F. japonica at the population level, highlighting the need for further ecological and genetic studies of population dynamics near the range limits to understand historic migration processes better.
The phytogeography and history of Japanese beech (Fagus crenata Blume and F. japonica Maxim.) forests are re‐examined in light of recent phytogeographical and palaeobotanical research advances. We briefly explain the phytosociological classification system of the Japanese beech forest and the geographical ranges of each vegetation type. We review studies of the geographic distribution of F. crenata and F. japonica at the population level, highlighting the need for further ecological and genetic studies of population dynamics near the range limits to understand historic migration processes better.
Summary
The intensity and frequency of droughts events are projected to increase in future with expected adverse effects for forests. Thus, information on the dynamics of tree water uptake from ...different soil layers during and after drought is crucial.
We applied an in situ water isotopologue monitoring system to determine the oxygen isotope composition in soil and xylem water of European beech with a 2‐h resolution together with measurements of soil water content, transpiration and tree water deficit. Using a Bayesian isotope mixing model, we inferred the relative and absolute contribution of water from four different soil layers to tree water use.
Beech took up more than 50% of its water from the uppermost 5 cm soil layer at the beginning of the 2018 drought, but then reduced absolute water uptake from the drying topsoil by 84%. The trees were not able to quantitatively compensate for restricted topsoil water availability by additional uptake from deeper soil layers, which is related to the fine root depth distribution. Absolute water uptake from the topsoil was restored to pre‐drought levels within 3 wk after rewetting.
These uptake patterns help to explain both the drought sensitivity of beech and its high recovery potential after drought release.
•Thermogravimetry coupled with Fourier transform infrared analysis was applied.•Estimation of kinetic parameters of beech wood by three model-free methods.•K-K method was used to predict the peak ...locations of three main components.•The gases evolved were identified by the spectra.•The heating rate had little influence on the produced composition.
Pyrolysis of beech wood (Fagus sylvatica) was investigated based on thermogravimetric analysis coupled with Fourier transform infrared spectrometry analysis at heating rates from 20K/min to 60K/min. The various activation energies were estimated at different conversions by three model-free methods and were in the range of 146.84–174.44kJ/mol. The peak locations of three main components (hemicellulose, cellulose and lignin) were predicted more exactly by the K-K method. The absorbance spectra corresponding to the three peak locations were basically the same at different heating rates, indicating that the heating rate had little influence on the produced composition. During the whole pyrolysis process, the evolution of gas components (CO, CO2, methane, methanol and formaldehyde) was consistent with the trend of derivative thermogravimetric curves, and possible formation pathways of main gases were tentatively presented. The amount of these five components produced in the order of most to least produced was formaldehyde>CO2 or methanol>methane>CO. In particular, the amount of formaldehyde was almost triple the amount of methanol and ten times the amount of methane at the maximum peak.
Root exudation is a key plant function with a large influence on soil organic matter dynamics and plant–soil feedbacks in forest ecosystems. Yet despite its importance, the main ecological drivers of ...root exudation in mature forest trees remain to be identified.
During two growing seasons, we analyzed the dependence of in situ collected root exudates on root morphology, soil chemistry and nutrient availability in six mature European beech (Fagus sylvatica L.) forests on a broad range of bedrock types.
Root morphology was a major driver of root exudation across the nutrient availability gradient. A doubling of specific root length exponentially increased exudation rates of mature trees by c. 5-fold. Root exudation was also closely negatively related to soil pH and nitrogen (N) availability. At acidic and N-poor sites, where fungal biomass was reduced, exudation rates were c. 3-fold higher than at N- and base-richer sites and correlated negatively with the activity of enzymes degrading less bioavailable carbon (C) and N in the bulk soil.
We conclude that root exudation increases on highly acidic, N-poor soils, in which fungal activity is reduced and a greater portion of the assimilated plant C is shifted to the external ecosystem C cycle.
Methods used to restore lapsed beech pollards by pruning were compared across four sites in northern Spain. Tree response, between five and 10 years after cutting, was compared with information about ...the cutting techniques used. The results provide further information about the techniques that maximise the success of working trees with this history of management in the Basque region of Spain, and furthers our understanding of managing these types of trees wherever they occur. When restoring lapsed pollards, choose trees in moderate shade with many branches. Retain at least three uncut branches spread around the tree, avoid cutting too close to the bolling and leave some foliage. If possible, cut branches less than 30 cm in diameter and with good epicormic growth. Cutting close to the bolling brings greater risks. A flow chart is provided to help the decision process.
•A new hybrid PSO-GA algorithm is proposed to gain advantages of PSO and GA.•Genetic evolution is incorporated into PSO to increase its population diversity.•TGA results of two pseudo solids and ...beech wood are analyzed.•Convergency efficiency and accuracy are both improved in PSO-GA.•Compensation effect is found in parameterizing pyrolysis model of wood.
A hybrid optimization algorithm, combining both Particle Swarm Optimization (PSO) and Genetic Algorithm (GA), is proposed to gain the favorable features of each individual algorithm when determining the pyrolysis kinetics of biomass. High convergence efficiency and the capability of avoiding being trapped in local optimal solution are primarily associated with PSO and GA, respectively. Gene operations in GA, including selection, crossover and mutation, are partially incorporated into PSO to increase the population diversity. Pyrolysis of beech wood was experimentally studied at three heating rates, and a numerical solver was established to simulate the pyrolysis details. In order to demonstrate the improved performance of PSO-GA, two pyrolysis models with given reaction schemes and kinetic parameters were adopted to create the acritical thermogravimetric analysis (TGA) curves. Then the kinetics was estimated using PSO-GA and individual GA and PSO. Subsequently, the experimental data were analyzed with the same manner. The results show that PSO-GA has the highest possibility of obtaining desired outcomes followed by PSO and then GA. With fixed population size, PSO-GA converges to a lower fitness function value, corresponding to higher accuracy. The attained kinetics of wood falls into the reported ranges in the literature. In some scenarios, the optimized results of hemicellulose and lignin contradict with the existing conclusions even though the global curves match the experimental measurements well. This implies the general concept of the pyrolysis process should also be given adequate consideration to avoid potential compensation effect when encountering complex issues.
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