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The introduction of non‐native tree species has become a global concern and may disrupt native communities and related ecosystem functions. Soil food webs regulate organic matter decomposition and nutrient cycling in forests with their feeding activities, but evaluating consequences of the introduction of tree species on soil invertebrates is challenging due to the complex trophic structure and wide range in body size of soil invertebrates. Here, we employed an energetic food web approach and estimated the energy flux in soil food webs using a four‐node model including soil meso‐ and macrofauna decomposers and predators. We examined pure and mixed stands of native European beech (Fagus sylvatica), introduced Douglas fir (Pseudotsuga menziesii) and native range‐expanding Norway spruce (Picea abies) across site conditions. Compared to native forests, introduced tree species reduced total fresh mass of macrofauna predators by 92% at sandy sites but not that of decomposers, suggesting trophic downgrading in soil food webs by Douglas fir. The energy flux in mixed forests was intermediate between respective monocultures, suggesting that tree mixtures mitigate potential negative impacts of introduced tree species on food web functioning. Across size classes, soil macrofauna responded more sensitively to changes in environmental conditions than soil mesofauna. Additionally, total energy flux positively correlated with species richness, pointing to the significance of soil biodiversity for trophic functionality. The energy flux through mesofauna outweighed that through macrofauna when considering energy loss to predators, highlighting the importance of mesofauna for decomposition processes in forest soil food webs. Overall, the study emphasizes the critical role of tree species composition, site conditions and soil biodiversity in driving energy flux through soil food webs and maintaining forest ecosystem functions. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

The digital image correlation (DIC) system is a powerful tool for measuring distributions of displacement and strain on the surface of a specimen. DIC systems are employed not only for homogeneous materials such as metals but also for heterogeneous materials such as wood. Although numerous validations of DIC system accuracy for metallic materials exist, the accuracy verification for wood, especially under multiaxial stress conditions, is less common. This study investigated the accuracy of a DIC system equipped with a bilateral telecentric lens on wood (Douglas fir). The accuracy verification in uniaxial stress fields was conducted through full compression testing, while verification in multiaxial stress fields was performed through partial compression testing. Additionally, compression tests on A6063 (aluminium alloy) were conducted to examine the differences in the DIC system accuracy between homogeneous and heterogeneous materials. The accuracy of the DIC system was assessed by comparing the results with those obtained from strain gauges. The results from the full compression tests indicate that the accuracy of axial strain measured by the DIC system was comparable for the specimens of A6063 and Douglas fir in the longitudinal (L) direction but was inferior for Douglas fir in the radial (R) direction. This is because the differences in the mechanical properties of earlywood and latewood produce high strain gradients. Furthermore, the differences in Young's modulus obtained from the DIC system and strain gauge for the specimens of A6063, Douglas fir (L), and Douglas fir (R) were − 1.23%, 2.26%, and − 12.5%, respectively. In the partial compression tests, the accuracy of strain components measured by the DIC system in the specimens of Douglas fir (R) was lower than that in A6063. In the partial compression tests, high strain gradients appear in multiple strain components, leading to a notable decrease in the accuracy of the DIC system compared to the full compression tests. [ABSTRACT FROM AUTHOR]

The mechanical properties of structural timber largely depend on the occurrence of knots and on fibre deviation in their vicinities. In recent strength grading machines, lasers and cameras are used to detect surface characteristics such as the size and position of knots and local fibre orientation. Since laser dot scanning only gives reliable information about the fibre orientation in the plane of board surfaces, simple assumptions are usually made to define the inner fibre orientation to model timber boards. Those models would be improved by better insight into real fibre deviation around knots. In the present work, a laboratory method is developed to evaluate growth layers geometries and fibre orientation, solely based on the fact that the fibers are parallel to the tree rings and without any further assumptions. The method simply relies on color scans and laser dot scans of Douglas fir (Pseudotsuga menziesii) timber specimen sections revealed by successive planing. The proposed method provides data on fibre orientation in 3D with an accuracy that is relevant for the calibration of detailed models. [ABSTRACT FROM AUTHOR]

AbstractSeedlings of 95 greenhouse-grown interior Douglas-fir half-sibling families originating from four breeding zones were subject to overwatering and periodic underwatering and compared to an optimally watered control (15 per family = 1425 seedlings total). Averaged over all trees, annual height was reduced by 4% and 11% compared to controls for overwatering and periodic underwatering, respectively. Family overwatered seedling height was 135–75%, and underwatered height was 100–75% of their respective control heights. Shorter families under stress grew like their control compared to taller families, but this was reversed in taller families when the watering conditions were ideal. A survival analysis indicated that after 30–50 days without water, family survival varied from 25% to 90%, and most trees died after 60 days. The breeding zone had little effect on the tolerance to suboptimal water or survival during complete water withdrawal and did not interact with watering treatments. Family traits for tolerance to overwatering favoured root biomass, traits for underwatering favoured reduced stem biomass, especially in ratio to roots, and traits for survival favoured belowground biomass over aboveground biomass. No tradeoffs between tolerance to over- and underwatering were found. Some families did well in all three conditions and some in one or the other. The study results suggest that variation in family growth and survival to suboptimal watering partly relate to root and stem biomass partitioning in the interior Douglas-fir population of British Columbia. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine suitable tree species to monitor and reduce Sn concentrations in the environment of Düzce province in Türkiye. A further goal was to test the hypothesis that, possibly due to air transport, the uptake of Sn in tree rings would show a significant and consistent dependency on compass direction. The timber samples were from the trunks of Tilia tomentosa (linden), Robinia pseudoacacia (black locust), Cedrus atlantica (cedar), Pseudotsuga menziesii (Douglas fir), and Fraxinus excelsior (European ash), which are commonly used in landscaping in Düzce province. Levels of Sn concentrations in annual rings were determined. Cedrus atlantica and F. excelsior were found to be suitable biomonitors that can be used to monitor changes in annual amounts of Sn contamination. Among the studied tree species, R. pseudoacacia had the highest average values and C. atlantica had the second-highest levels of Sn uptake. However, no consistent dependency on compass direction was found. It follows that rather than depending on the direction of prevailing winds, the uptake of metals to the xylem of trees must be due to direction-independent processes, such as transport via roots and xylem or absorption into leaves and subsequent transport via the phloem. [ABSTRACT FROM AUTHOR]

Mixed-species forests are, for multiple reasons, promising options for forest management in Central Europe. However, the extent to which interspecific competition affects tree hydrological processes is not clear. High-resolution dendrometers capture subdaily variations in stem diameter; they can simultaneously monitor stem growth (irreversible changes in diameter) and water status (reversible changes) of individual trees. Using the information on water status, we aimed to assess potential effects of tree species mixture, expressed as local neighborhood identity, on night-time rehydration and water stress. We deployed 112 sensors in pure and mixed forest stands of European beech, Norway spruce and Douglas fir on four sites in the northwestern Germany, measuring stem diameter in 10-min intervals for a period of four years (2019–2022). In a mixture distribution model, we used environmental variables, namely soil matric potential, atmospheric vapor pressure deficit, temperature, precipitation and neighborhood identity to explain night-time rehydration, measured as the daily minimum tree water deficit (TWDmin). TWDmin was used as a daily indicator of water stress and the daily occurrence of sufficient water supply, allowing for stem growth (potential growth). We found that species and neighborhood identity affected night-time rehydration, but the impacts varied depending on soil water availability. While there was no effect at high water availability, increasing drought revealed species-specific patterns. Beech improved night-time rehydration in mixture with Douglas fir, but not in mixture with spruce. Douglas fir, however, only improved rehydration at a smaller share of beech in the neighborhood, while beech dominance tended to reverse this effect. Spruce was adversely affected when mixed with beech. At species level and under dry conditions, we found that night-time rehydration was reduced in all species, but beech had a greater capacity to rehydrate under high to moderate soil water availability than the conifers, even under high atmospheric water demand. Our study gives new insights into neighborhood effects on tree water status and highlights the importance of species-specific characteristics for tree-water relations in mixed-species forests. It shows that drought stress of European beech can be reduced by admixing Douglas fir, which may point towards a strategy to adapt beech stands to climate change. [ABSTRACT FROM AUTHOR]

The ongoing climate change calls for managing forest ecosystems in temperate regions toward more drought‐resistant and climate‐resilient stands. Yet ecological consequences of management options such as planting non‐native tree species and mixing coniferous and deciduous tree species have been little studied, especially on soil animal communities, key in litter decomposition and pest control. Here, we investigated the taxonomic and trophic structure of soil macrofauna communities in five forest types including native European beech (Fagus sylvatica), range‐expanding Norway spruce (Picea abies) and non‐native Douglas fir (Pseudotsuga menziesii) as well as conifer‐beech mixtures across loamy and sandy sites in northern Germany. Abundance of primary decomposers (feeding predominantly on litter) was high in Douglas fir and beech forests, benefiting from less acidic soil and more favorable litter resources compared to spruce forests, while secondary decomposers (feeding predominantly on microorganisms and microbial residues) reached highest densities in spruce forests. Differences in abundance and species richness among forest types generally varied between regions and were most pronounced in Douglas fir of the sandy region. However, trophic guilds differed more between regions than between forest types, indicating that environmental factors outweigh the importance of forest type on soil macrofauna communities. The analysis of stable isotopes (δ15N and δ13C values) supported the general robustness in trophic position of macrofauna trophic guilds against variations in forest types and regions, but indicated reduced detrital shifts and food‐chain lengths in coniferous compared to European beech forests with mixtures mitigating these effects. Overall, for evaluating consequences of future forest management practices on the structure and functioning of soil animal communities, regional factors need to be considered, but in particular at loamy sites the taxonomic and trophic structure of soil macrofauna communities are resistant against changes in forest types. [ABSTRACT FROM AUTHOR]

Suillus (order Boletales) is a diverse genus of epigeous, mushroom-forming fungi native to temperate forests across the Northern Hemisphere; however, some species are also present in areas where Pinaceae has been introduced in the Southern Hemisphere. Unlike the closely related genus Rhizopogon, there are no described hypogeous, sequestrate species of Suillus. Here, we describe Suillus hypogaeus, the first known species of the genus with hypogeous, sequestrate sporocarps. Collections were made on Marys Peak in Benton County, Oregon, USA, at an elevation of 800 m in forests dominated by Pseudotsuga menziesii var. menziesii. The peridium is white, quickly staining pink to purple-reddish where bruised or cut. The gleba is pale yellow when young, becoming purple with maturity, and the basidiospores are obovoid, light yellow in KOH, and amyloid in Melzer's reagent. Multilocus molecular phylogenetic analyses support the placement of S. hypogaeus among the Larix specialists in the spectabilis group of Suillus. Although Larix and Pseudotsuga are sister genera, Larix does not occur on Marys Peak or elsewhere in western Oregon. Suillus hypogaeus, therefore, represents both an independent origin of the hypogeous, sequestrate sporocarp within the Boletales and an independent host shift between Larix and Pseudotsuga within the genus Suillus. [ABSTRACT FROM AUTHOR]

Summary: Ectomycorrhizal (ECM) fungi distribute tree‐derived carbon (C) via belowground hyphal networks in forest ecosystems. Here, we asked the following: (1) Is C transferred belowground to a neighboring tree retained in fungal structures or transported within the recipient tree? (2) Is the overlap of ectomycorrhizal fungi in mycorrhizal networks related to the amount of belowground C transfer?We used potted sapling pairs of European beech (Fagus sylvatica) and North‐American Douglas‐fir (Pseudotsuga menziesii) for 13CO2 pulse‐labeling. We compared 13C transfer from beech (donor) to either beech or Douglas‐fir (recipient) and identified the ECM species. We measured the 13C enrichment in soil, plant tissues, and ECM fractions of fungal‐containing parts and plant transport tissues.In recipients, only fungal‐containing tissue of ectomycorrhizas was significantly enriched in 13C and not the plant tissue. Douglas‐fir recipients shared on average one ECM species with donors and had a lower 13C enrichment than beech recipients, which shared on average three species with donors.Our results support that recently assimilated C transferred belowground is shared among fungi colonizing tree roots but not among trees. In mixed forests with beech and Douglas‐fir, the links for C movement might be hampered due to low mycorrhizal overlap with consequences for soil C cycling. [ABSTRACT FROM AUTHOR]

Non‐native tree species and mixed forests have been increasingly employed in forestry practice as a safeguard against climate change and as a tool to foster biodiversity while providing economic benefits. Though these changes in forest composition may affect animal communities and ecosystem processes, they are seldom studied through a plant–animal interaction perspective.Here we investigated how forests with varying proportions of a native broadleaf (Fagus sylvatica) and two conifers (introduced Pseudotsuga menziesii and native Picea abies) affect rodents and their interactions with seeds. We surveyed terrestrial small mammal communities, estimated species' densities, assessed seed preference by rodents, collected data on environmental variables (understory density and tree basal area), measured Fagus sylvatica seed production and tracked 1200 seeds of Fagus sylvatica in 20 different forest plots in northern Germany in a mast and non‐mast year for Fagus sylvatica.Forest composition influenced the interactions between rodents and seeds. In forests with a lower proportion of broadleaves, beech seeds were harvested faster and in greater quantities, had diminished survival and were less often cached. These results are in agreement with three other findings: (a) seed fate responded to the proportion of broadleaves and conifers irrespective of conifer tree identity, (b) rodents preferred nutritious beech seeds over small conifer seeds, and (c) higher proportions of seeds were harvested during the period when beech seeds were scarce (non‐mast year).Synthesis and applications: This work provides evidence of how forest composition can affect plant–animal interactions without necessarily altering animal communities or population densities. Specifically, we found no differences between forests with native and non‐native conifer trees regarding small mammal community, seed‐rodent interactions or seed fate. Furthermore, rodents may provide a service in mixed forests by primarily preying upon seeds of Fagus sylvatica, a superior‐competitive species, and thus mitigate beech dominance over conifer species. [ABSTRACT FROM AUTHOR]

Decay levels of wooden components in the Yang former residence were classified using polarized light and fluorescence methods. Analysis of the decay cause was conducted based on external conditions and wood species characteristics. The polarization and fluorescence effects revealed that there were varying degrees of decay in larch (Larix potaninii var. australis), spruce (Picea brachytyla), lace-bark pine (Pinus bungeana), Masson pine (Pinus massoniana), Chinese Douglas fir (Pseudotsuga sinensis), Chinese fir (Cunninghamia lanceolata), poplar (Populus tomentosa), and elm (Ulmus pumila). The primary factors contributing to decay included the inherent low natural durability of the wood species and adverse external conditions, such as damaged roofs, missing dripping water and tiles causing water leakage, uneven indoor and outdoor ground levels, contemporary tile paving indoors, and inadequate ventilation. This study aims to establish a scientific basis for subsequent conservation strategies. [ABSTRACT FROM AUTHOR]

Disentangling the factors influencing the climate sensitivity of trees is crucial to understanding the susceptibility of forests to climate change. Reducing tree-to-tree competition and mixing tree species are two strategies often promoted to reduce the drought sensitivity of trees, but it is unclear how effective these measures are in different ecosystems. Here, we studied the growth and physiological responses to climate and severe droughts of silver fir and Douglas-fir growing in pure and mixed conditions at three sites in Switzerland. We used tree-ring width data and carbon (δ13C), oxygen (δ18O) and hydrogen (δ2H) stable isotope ratios from tree-ring cellulose to gain novel information on water relations and the physiology of trees in response to drought and how tree species mixture and competition modulate these responses. We found significant differences in isotope ratios between trees growing in pure and mixed conditions for the two species, although these differences varied between sites, e.g. trees growing in mixed conditions had higher δ13C values and tree-ring width than trees growing in pure conditions for two of the sites. For both species, differences between trees in pure and mixed conditions regarding their sensitivity to temperature, precipitation, climatic water balance and vapor pressure deficit were minor. Furthermore, trees growing in pure and mixed conditions showed similar responses of tree-ring width and isotope ratios to the past severe droughts of 2003, 2015 and 2018. Competition had only a significantly negative effect on δ13C of silver fir, which may suggest a decrease in photosynthesis due to higher competition for light and nutrients. Our study highlights that tree species mixture may have only moderate effects on the radial growth and physiological responses of silver fir and Douglas-fir to climatic conditions and that site condition effects may dominate over mixture effects. [ABSTRACT FROM AUTHOR]

The flexural behavior of hybrid timber–steel encased beams comprising coniferous radiata pine (Pinus radiata) (MGP10) and Douglas fir (Pseudotsuga menziesii) (F8) timber lamellae with bonded-in steel bars is studied. The effect of cross-section depth, steel bar size, timber species/grade, and steel bar arrangements (only bottom and top-and-bottom) on the hybrid beams' stiffness, failure mode, ductility, and load-carrying capacity were investigated. The flexural capacity and stiffness of the doubly (top-and-bottom) reinforced beams are increased by 127% and 71%, respectively. However, in the singly (bottom) reinforced beams, the flexural capacity and stiffness are increased only by 41% and 25%, respectively, highlighting the important role of the compressive bars. The failure of all beams was associated with tensile flexural failure of timber, but the steel bars improved the ductility of the beams. The maximum coefficient of variation of the peak load in hybrid beams (CoV=14.3%) is lower than that of the bare timber beams (CoV=21.7%). Two analytical models were developed based on a linear and a bilinear stress–strain relationship for timber. The analytically predicted peak load and stiffness agree well (less than 13% and 12% difference) with the experimental results. [ABSTRACT FROM AUTHOR]

In this study, the effects of defoliation caused by fungal pathogens on the tree vitality and growth of a 33-year old Douglas-fir (Pseudotsuga menziesii) provenance plantation in northwestern Bulgaria was presented. The results of the conducted surveys in 2011 and 2020 showed that there were significant differences between the individual provenances of Douglas-fir concerning their susceptibility to the needle cast diseases, caused by the fungal pathogens Rhabdocline pseudotsugae and Phaeucryptopus gaeumannii. The extent of damage, expressed as the amount of Douglas-fir needles cast, varied among provenance groups in individual years. A serious degree of defoliation was assessed among all continental provenances. In 2011, all examined trees from the group of continental provenances had severe symptoms of the needle cast disease. In 71.5% of them, the defoliation of the crowns was over 25% – moderately to severely affected. The average degree of defoliation varied from 18.3% (32 Wаrm Springs) to 89.3% (55 Alamogordo). In 2020, severe defoliation was found among all continental provenances. Both fungal pathogens were found as causes of the defoliation of 64.3% of the trees. The growth indicators: average height, average diameter at breast height, average height- and diameter increment for survived provenances in 2011 (at age 24) and 2020 (at age 33) were evaluated. The loss of needles and the reduced physiological function of the trees affected their vitality in the following years. Relationships between the average current annual height and diameter increment by provenance groups for 2003–2011 and 2011–2020 were calculated. It was found that with an increase in the degree of defoliation, the height and diameter increment of the provenances decreases. [ABSTRACT FROM AUTHOR]

Dental fear and anxiety (DFA) is known as an immense challenge in oral healthcare, which can result in compromised oral health, pain, and uncomfortable treatment. The objective of this study was to analyze the effect of essential-oil vaporization on acute anxiety of patients in dental practices. Four dental practices used five weekly cycles of vaporization with each scent: Orange (Citrus sinensis), Swiss Pine (Pinus cembra), Good Mood (blended essential oils: Citrus sinensis, Citrus aurantifolia, Citrus limon, Osmanthus fragrance (5%)), Forest Walk (blended essential oils: Abies grandis, Pinus cembra, Myrtus communis c. t. 1,8-cineol, Abies alba, Citrus paradisi, Abies sibirica, Pseudotsuga menziesii, Vetiveria zizanoides), and water. Acute anxiety was the primary outcome (state-trait-anxiety inventory (STAI-S)). Secondary outcomes were trait anxiety (STAI-T), dental anxiety (Kleinknecht dental fear survey), and pain perception in treatment (numeric rating scale). Across all patients (n = 486), STAI-S was slightly higher in the control group (40.7 ± 11.6) than in the intervention groups (38.4 ± 10.5). Post-hoc analyses revealed that the effect is only robust for the subgroup of female patients (n = 296, p = 0.044). We also conducted a post-hoc additional analysis on a subpopulation with an increased level of STAI-T ≥ 42 (n = 131 patients). For this group the difference in acute anxiety between the control group (51.1 ± 11.9, n = 30) vs. the intervention groups (46.8 ± 9.6, n = 118) was significant (T = 4.39, p = 0.0379). The results of the study indicate a promising potential of essential-oil vaporization to alleviate dental anxiety, particularly in the subgroups of patients with a high level of trait anxiety, and particularly in female patients. The calming effects of the essential-oil vaporization were also highlighted by the anecdotical statements of the dental-practice staff. The anxiety-reducing role of essential-oil vaporization alone and as one part of combined techniques to counter DFA should be further explored using multi-perspective methodological approaches in research. [ABSTRACT FROM AUTHOR]

The conversion of biomass into bio-oil through the pyrolysis process offers numerous benefits, such as bio-fuel and bio-resin synthesis. However, for bio-oil usage for any application, understanding its composition is vital. Therefore, this study investigated the effects of different commonly available woody biomass (Douglas fir, eucalyptus, and poplar) on bio-oil composition. The bio-oil was produced through fast pyrolysis at 500 °C in a fluidized bed reactor and collected using an electrostatic precipitator. The chemical composition was analyzed using gas chromatography–mass spectroscopy, and the hydroxyl groups were quantified using phosphorous-31 nuclear magnetic resonance. The poplar bio-oil had the most significant proportion (67 area%) of lignin-derived compounds and the highest OH concentration (6 mmol g−1). However, the proportion of carbohydrate-derived compounds was the largest (44 area %) in bio-oil produced from Douglas fir. Based on the OH concentration, poplar would be the most suitable feedstock for resin synthesis among the three feedstocks tested. [ABSTRACT FROM AUTHOR]

Ten new taxa of gymnosperms are added to the non-indigenous woody flora of Tunisia, after almost two decades of botanical surveys. Four of them (Cryptomeria japonica, Pinus brutia var. pityusa, Pseudotsuga menziesii var. glauca, Taxodium distichum var. distichum) are also new for the flora of North Africa. Pinus coulteri is here first reported for the Mediterranean Basin. Three genera (Cryptomeria, Pseudotsuga and Taxodium) are firstly recorded for the non-native vascular flora of Africa whereas two genera (Cedrus and Platycladus) are reported for the first time only for the woody flora of Tunisia. Brief descriptions together with filed photographs, global distributions and habitats at national scale are provided. Some taxonomic comments on their distinguishable features as well as updated keys are also presented. [ABSTRACT FROM AUTHOR]

In IUFRO experimental plots of 1969–1970, two 'Italian' provenances, I11 and I15, of unknown genetic origins, have consistently exhibited remarkable performance and stability over time and space in previous studies. It was deemed essential to acquire knowledge about the genetic origin area and conduct a genetic characterization of these two Italian provenances for their formal registration. Considering the observed intraspecific genetic variation across the American geographic cline, it was imperative to ensure that the selected provenances adequately represented diverse eco-physiological regions within the species range. To achieve this, most likely American provenances were selected, building upon historical document hypotheses and aiming to cover various geo-climatic areas. Specifically, five coastal variety and three interior variety provenances were chosen, two for each major geo-climatic region. The results obtained, using seven microsatellites, through four genetic structure analysis methods, predominantly attributed I11 to the area around 1080 origin, Washington Cascades region and 1094, Oregon Coast area. Similarly, I15 was primarily attributed to the area around the 1096 provenances, the Oregon Cascades region, compared to other coastal areas it appeared to differ. Among the three interior origins, 1162 from Arizona, Interior South area, exhibited intermediate genetic characteristics between the two varieties, despite its geographical location falling within the range of the interior variety. Similar to our expectations, comparing the distinct characteristics of the origin areas for each Italian provenance, it becomes feasible to complete their certification as 'seed stands' and to plan an appropriate management strategy for the species' diffusion. [ABSTRACT FROM AUTHOR]

Forest soils are a critical component of terrestrial ecosystems and host a large number of animal decomposer species. One diverse and abundant decomposer taxon is oribatid mites (Acari: Oribatida), whose species composition varies with forest type and tree species composition. We used functional traits that indicate different niche dimensions, to infer assembly processes of oribatid mite communities in monocultures and mixed forests of native and introduced tree species. We found that coexisting species differed more in the resource‐related niche dimension, i.e., reproductive mode and trophic guild, than in the morphological dimension, e.g., body length and width, sclerotization and concealability. These results suggest that both filtering and partitioning processes structure oribatid mite communities. In native European beech forests, but not in non‐native Douglas fir forests, oribatid mites were mainly structured by filtering processes acting via traits related both to environmental tolerance and to resources. Furthermore, oribatid mite trait diversity, but not phylogenetic diversity, differed significantly between monocultures and mixed forests, demonstrating that multidimensional diversity indices provide additional information on soil biodiversity. Overall, the study provides evidence that traits representing different niche dimensions need to be considered for understanding assembly processes in soil animal communities and thereby soil biodiversity. [ABSTRACT FROM AUTHOR]

Douglas‐fir [Pseudotsuga menziesii (Mirb.) Franco] is the predominant forest plantation species in the Pacific Northwest (PNW), with site productivity and fertilizer response influenced by climate and soil variations. This study investigates the utility of in situ 12‐week supply measurements of nitrogen (N), calcium (Ca), and phosphorus (P) to ion‐exchange resins (specifically Plant Root Simulator [PRS] probes) to estimate carbon (C):N ratios, soil nutrient contents (0–1 m), foliar nutrient concentrations, Douglas‐fir productivity (site index and basal area mean annual increment), and fertilizer volume response. PRS nutrient supply rates were correlated with N, Ca, and P soil nutrient contents (0–1 m), C:N ratios, and foliar nutrient concentrations. Low PRS NO3 supply rates (<25 mg N·m−2·burial period−1) were correlated with lower Douglas‐fir productivity and greater fertilizer volume response. PRS NO3 supply rates performed as well as total soil N contents and foliar N concentrations at estimating volume growth response to fertilizer. Twelve weeks after fertilization, PRS NO3, NH4, and Ca supply rates were significantly elevated compared to the unfertilized treatment. This research found that PRS probes were an effective in situ tool and are recommended for understanding N, Ca, and P nutrient availabilities, site productivity, and fertilizer response in Douglas‐fir plantations and for developing fertilizer prescriptions. Core Ideas: Plant Root Simulator (PRS) ion‐exchange resins estimated N, Ca, and P availability in Douglas‐fir forests.Soils with low PRS NO3 resulted in lower Douglas‐fir site index and basal area mean annual increment.Greater fertilizer response of Douglas‐fir was found on soils with low PRS NO3 and soil total N.Urea fertilization increased PRS NO3, NH4, and Ca supply rates after 12 weeks.In a subset of installations, PRS NO3 and NH4 were reduced to control levels after 32 weeks. [ABSTRACT FROM AUTHOR]

To increase the resilience of forests to drought and other hazards, foresters are increasingly planting mixed stands. This requires knowledge about the drought response of tree species in pure and mixed-culture neighborhoods. In addition, drought frequently interacts with continued atmospheric nitrogen (N) deposition. To disentangle these factors for European beech, Norway spruce and Douglas fir, we conducted a replicated 3-factorial sapling growth experiment with three moisture levels, (high, medium, and low), two N levels (high and ambient), and pure and mixed-culture neighborhoods. We measured biomass, stomatal conductance (GS), shoot water potential (at predawn: ΨPD, midday, and turgor loss point: ΨTLP), branch xylem embolism resistance (Ψ50) and minimum epidermal conductance (G min). The three species differed most with respect to G min (10-fold higher in beech than in the conifers), hydroscape area (larger in beech), and the time elapsed to reach stomatal closure (TΨGS90) and ΨTLP (TTLP; shorter in beech), while Ψ50 and ΨTLP were remarkably similar. Neighborhood (pure vs mixed-culture) influenced biomass production, water status and hydraulic traits, notably G S (higher in Douglas fir, but lower in spruce and beech, in mixtures than pure culture), hydraulic safety margin (smaller for beech in mixtures), and TΨGS90 and TTLP (shorter for spruce in mixture). High N generally increased GS , but no consistent N effects on leaf water status and hydraulic traits were detected, suggesting that neighbor identity had a larger effect on plant water relations than N availability. We conclude that both tree neighborhood and N availability modulate the drought response of beech, spruce, and Douglas fir. Species mixing can alleviate the drought stress of some species, but often by disadvantaging other species. Thus, our study suggests that stabilizing and building resilience of production forests against a drier and warmer climate may depend primarily on the right species choice; species mixing can support the agenda. [ABSTRACT FROM AUTHOR]

We assessed the impacts of three approaches to thinning from below with varying spatial patterns on several stand and individual tree variables for interior Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco), interior spruce (Picea glauca (Moench) Voss × Picea engelmannii Engelm.), and lodgepole pine (Pinus contorta Dougl. Ex Loud. var. latifolia Englem.) in central British Columbia, Canada. The three thinning treatments were two experimental "clumped" treatments (3 m Clumped and 5 m Clumped) and the Standard (more uniform spacing) thinning treatment that was employed operationally at that time. We used long-term data from 24 plots measured five times over 21 years. Thinning increased stand basal area increment, with the plots that received the 5 m Clumped treatment having significantly higher periodic annual relative basal area increment than the unthinned Control plots. The responses for the two clumped treatments were not any lower than the Standard. The 3 m Clumped treatment was best if one is concerned about fast recovery of the growing space; however, the 5 m Clumped spacing treatment may be preferable if higher individual tree vigour is needed for resistance and resilience to fire, insects, and disease. [ABSTRACT FROM AUTHOR]

Fire suppression has increased competitive tree encroachment of Oregon white oak (Quercus garryanna Douglas ex Hook) ecosystems, threatening maintenance of this important species. Restoration of oak ecosystems is ideal to address this threat but not always possible, giving rise to a need for novel treatments that will allow oak to persist on an altered landscape. We tested the effect of three release treatments centered around individual Oregon oak trees within four forested sites that had developed following encroachment and overtopping by Douglas‐fir (Pseudotsuga menziesii [Mirb.] Franco var. menziesii). The release treatments entailed removal of competitive tree species (>10 cm dimaeter at breast heigh [DBH]) within zero (as control), half, or full distance of the associated Oregon oak trees' height. There was no effect of release treatment on height, but diameter was significantly increased in the full release treatment relative to both the control and half release treatments. The effect on diameter increased up to year 10 and then decreased to year 20. Growth response to canopy damage from an ice storm in year 12 of the study varied significantly with treatment; growth was negatively related to the percent crown damage in both release treatments but not the control treatment. Full release treatments around individual Oregon oak trees can have long‐term positive effects on growth, providing managers with an option to maintain oak within altered ecosystems. [ABSTRACT FROM AUTHOR]

Studying the species diversity and condition of monumental trees contributes to their preservation and is important for public awareness of their role in ecosystems and the country's ecological heritage. The purpose of the study was to reveal the significance of such trees for society. The task of the work was to research the characteristics of monumental trees in Ukraine. The history of environmental protection is analysed and the features of monumental tree preservation in Ukraine are presented. The beginning of environmental protection activity related to the preservation of trees in Ukraine and the most active periods have been revealed of it. The national features of the popularization of monumental trees are given. Based on the analysis of botanical natural monuments cadastres of Ukraine and Kyiv, quantitative and species composition of monumental trees were established. The most common (Quercus robur), common, less common and rare (Buxus sempervirens, Catalpa bignonioides, Metasequoia glyptostroboides, Pseudotsuga menziesii, Rhododendron myrtifolium, Sequoiadendron giganteum and others) species of monumental trees have been established, and important issues regarding their conservation are indicated. According to the types of street plantings, the majority (68%) are single trees. To assess the awareness of the population about ancient trees, the method of sociological survey of respondents was used. The most significant values of monumental trees for the population were studied. The importance of the populations' awareness of old trees through the development of an emotional connection with them, which contributes to their protection, has been established. The obtained results can be used in future environmental protection activity, exchanging of scientists' experience from different countries regarding the preservation of such trees, enrichment of information about growth characteristics, historical facts or other issues related to these trees [ABSTRACT FROM AUTHOR]

Bark residues from Douglas fir are an abundant resource that is currently used primarily in low-value energy recovery or is landfilled. Bark extractives are rich in diverse compounds like terpenes, fatty acids, phenols, and sugars with potential uses in a variety of high value applications. The study explores the potential of enzymatic hydrolysis to improve phenolic compounds from Douglas fir bark. It also assesses differences in chemical composition among rhytidome, phloem, and comingled bark fractions from an industrial waste pile. Phloem fractions exhibit higher yields of extractives, rhytidome fractions have elevated lignin levels, while the comingled fraction lies between the two except in ash content which was higher than in the separated fractions. Fungal decay tests with Gloeophyllum trabeum and Coniophora puteana on extract treated wood suggest potential for growth inhibition in extracts, about 58–31 % and 30–7% mass loss (in average) respectively, but due to high mass loss at low concentrations an enzymatic modification approach seems crucial for enhanced inhibition. Growth responses in whole-cell fermentation approach display variability depending on the participating microorganisms. Enzymatic hydrolysis with beta-glucosidase improved the antioxidant properties of bark extracts and holds promise for altering the chemical composition and enhancing bioactivity. [ABSTRACT FROM AUTHOR]

Mixed-species forests can provide higher levels of ecosystem functions and services and can be more resistant and resilient in the face of global change. While many studies focus on the growth and yield of mixed forests, fewer have examined the underlying processes. Inter- or intra-specific differences and interactions influence tree- and stand-level light absorption by determining the vertical structure of stratified canopies, stand density, leaf area index, and the size or allometry of trees. While canopy light absorption is a very important process, it is difficult to quantify it for individual species within a mixture and is rarely examined. A detailed tree-level model (MAESTRA) was used in combination with measurements of tree sizes and stand structures to examine effects of mixing on absorbed photosynthetically active radiation (APAR) in 41–63-year-old stands of Pseudotsuga menziesii and Fagus sylvatica at three sites in Bavaria, Germany. The effects of initial stand density on APAR were analysed in 46-year-old P. menziesii stands of a spacing experiment at two sites. At the tree level, mixing increased mean height and leaf area, growth (185% higher) and APAR (85% higher) of P. menziesii at all sites. Mean tree heights and crown sizes of F. sylvatica were larger in mixtures, while recent growth rates and APAR were not significantly different to monocultures. Planting density did not influence mean tree variables (e.g. height, leaf area, crown volume), because any initial spacing effects had been gradually removed by thinning across all treatments. At the stand level, there were no differences in growth, basal area or in the annual growth per annual APAR (light use efficiency, LUE) between monocultures and mixtures. The highest APAR values were observed in P. menziesii monocultures, while the lowest APAR values were observed in F. sylvatica monocultures. While mixing these species may not increase stand-level growth during later phases of development, mixing accelerated initial growth of individual trees and reduced the time to reach target diameters, which are both important aspects in adapting forests to global change. [ABSTRACT FROM AUTHOR]

Phytophthora pluvialis is an oomycete that primarily infects Pinus radiata and Pseudotsuga menziesii causing the destructive foliar disease red needle cast (RNC). Recent observations show that P. pluvialis can also infect western hemlock inducing resinous cankers. High-throughput and reproducible infection assays are integral to find key information on tree health and oomycete pathogenicity. In this protocol, we describe the propagation and spore induction of P. pluvialis, followed by detached needle assays for verification and quantification of virulence of P. pluvialis in P. radiata needles. These needle assays can be employed for high-throughput screening of tree needles with diverse genetic backgrounds. In downstream analysis, Quantitative PCR (qPCR) was utilized to assess relative gene expression, as exemplified by candidate RxLR effector protein PpR01. Additional techniques like RNA sequencing, metabolomics, and proteomics can be combined with needle assays and can offer comprehensive insights into P. pluvialis infection mechanisms. [ABSTRACT FROM AUTHOR]

Fire injury stresses Douglas-fir trees (Pseudotsuga menziesii) that survive a wildfire event, allowing subsequent Douglas-fir beetle (Dendroctonus pseudotsugae) infection to kill trees that may have otherwise survived. This study aimed to determine how fire injury, stand, and tree characteristics drive Douglas-fir beetle host tree selection five years post-fire. We paired 28 adjacent beetle-infected and uninfected stands (infected N = 14) and 140 Douglas-fir trees (infected N = 70) within the 416 Fire burn area in Southwest Colorado. We found no statistically significant differences between infected and uninfected stand characteristics. Individual tree height, DBH, and bark char severity index were significantly higher in infected versus uninfected trees. We created a regression decision tree model to determine the influence of fire injury and tree characteristics on the probability of infection. Trees with a height ≥ 27 m, bark char height < 2.3 m, and DBH < 80 cm had the greatest probability of attack (100%). Trees with a height < 27 m, bark char severity index < 5.5, and DBH < 49 cm had the lowest probability of attack (3.7%). Understanding the influence of fire on Douglas-fir beetle host selection allows land managers to model potential epidemic outbreaks and guide proactive management actions that may reduce beetle outbreak severity or preserve high-value trees not killed by fire. [ABSTRACT FROM AUTHOR]

Copper is a non-biodegradable heavy metal, and high levels in water bodies cause serious environmental and health issues. Douglas fir biochar has a higher number of carboxylic, phenolic, and lactonic groups, which provide suitable active sites for copper removal. Douglas fir biochar (BC) was modified using 20% solutions of KOH (KOH/BC), H2SO4, (H2SO4/BC), and Na2CO3 (Na2CO3/BC). All materials were characterized using SEM, SEM-EDS, FTIR, TGA, XRD, BET, and elemental analysis. These modifications were done to compare the activations of those sites by measuring copper removal efficiencies. KOH/BC, H2SO4/BC, and Na2CO3/BC materials gave surface areas of 389.3, 326.7, and 367.9 m2 g−1, respectively, compared with pristine biochar with a surface area of 578.9 m2 g−1. The maximum Langmuir adsorption capacities for Na2CO3/BC, KOH/BC, BC, and H2SO4/BC were 24.79, 18.31, 17.38, and 9.17 mg g−1, respectively. All three modifications gave faster kinetics at 2 mg/L initial copper concentrations (pH 5) compared with pristine BC. The copper removal efficiency was demonstrated in four different spiked real water matrices. The copper removals of all four water matrices were above 90% at 2 mg/L initial concentration with a 2 g/L biochar dosage. The competitive effects of Pb2+, Zn2+, Cd2+, and Mg2+ were studied at equimolar concentrations of Cu2+ and competitive ions for all four materials. [ABSTRACT FROM AUTHOR]

In an effort to ameliorate the impacts of climate change, forest managers in Central Europe increasingly turn to conifer species that produce higher yields and are better adapted to projected future climatic conditions. Though small mammals are an important component of the forest ecosystem, the impacts of enriching native broadleaf forests with conifers on small mammal communities are not well understood. We conducted mark–recapture surveys of small mammals to ascertain differences in their community structure among stands of two conifers (native Norway spruce Picea abies and non-native Douglas fir Pseudotsuga menziesii) and the dominant broadleaf in the region, European beech (Fagus sylvatica). After estimating the density of two common species, the yellow-necked mouse Apodemus flavicollis and bank vole Clethrionomys glareolus, we found that the population density of each is positively related to the proportion of beech and negatively to the proportion of conifers in each stand, though these effects of stand composition are smaller than the positive effect of herb cover. Increasing Norway spruce proportion reduced monthly survival of small mammals, while Douglas fir proportion had a positive effect on survival. We conclude that the two conifer species have similar impacts on small mammal density, though overall small mammal survival was significantly lower on plots with Norway spruce. This suggests that increasing the proportion of Douglas fir at the expense of Norway spruce may be possible without significantly changing local patterns of small mammal population density, but further research is necessary to elucidate the exact impacts of these two conifer species on small mammal demography and behavior. [ABSTRACT FROM AUTHOR]

Nowadays, an increased concern regarding using natural products for their health benefits can be observed. The aim of this study was to assess and compare several phenolic compounds found in 15- to 60-year-old Douglas fir, silver fir, larch, pine, and spruce needle and bark extracts and to evaluate their antioxidant and antimicrobial activities. Spectrophotometric assays were used to determine the total polyphenol content and the antioxidant activity that was assessed by using the DPPH• radical scavenging assay (RSA), the ferric reducing antioxidant power assay (FRAP), and the ABTS•+ radical cation scavenging assay (ABTS). The phytochemical content was determined by using high-performance liquid chromatography, and the antimicrobial activity was determined by assessing the minimal inhibition concentration (MIC). The results of the study show a total polyphenol content of 62.45–109.80 mg GAE/g d.w. and an antioxidant activity of 91.18–99.32% for RSA, 29.16–35.74 µmol TE/g d.w. for FRAP, and 38.23–53.57 µmol TE/g d.w. for ABTS. The greatest quantity of phenolic compound for most of the extracts was for (+)-catechin, and it had values between 165.79 and 5343.27 µg/g d.w. for these samples. The antimicrobial inhibition for all the extracts was the strongest for Staphylococcus aureus (MIC 62.5–125 µg/mL). The extracts analyzed could be used for their bioactive potential after further investigations. [ABSTRACT FROM AUTHOR]

Douglas-fir (Pseudotsuga menziesii (Mirbel) Franco) is the most important commercial timber species in the United States Pacific Northwest (US PNW). Owing to its significance, Douglas-fir has been the subject of long-term tree improvement. First-generation and second-generation progeny tests are available for wood property evaluation, but aside from specific gravity (from increment cores) and stiffness (usually determined on standing trees using acoustics), the estimation of genetic parameters has been limited. There is interest in evaluating trees for wood stiffness, but the cost of evaluation is generally a barrier. Near infrared hyperspectral imaging (NIR-HSI) may provide a rapid technique for the estimation of a variety of wood properties, providing wood property data is available for building predictive models. In this study, SilviScan was used to assess tracheid properties (wall thickness, coarseness, specific surface and radial and tangential diameter), air-dry density, microfibril angle (MFA) and stiffness for 40 calibration samples, 20 each from two progeny tests aged ten and twelve years, respectively (500 samples in all, one test site from each of two independent first-generation breeding programs). Wood properties were measured on sections of increment cores representing the five growth rings adjacent to the bark. Based on the NIR-HSI and SilviScan data from the 40 calibration samples, models were built to predict wood properties of all samples. These data were used to estimate heritabilities and trait-to-trait genetic correlations. Results from this preliminary study are encouraging and the technique can be explored on larger, multi-site, datasets. [ABSTRACT FROM AUTHOR]

Tree-ring δ15N may depict site-specific, long-term patterns in nitrogen (N) dynamics under N2-fixing species, but field trials with N2-fixing tree species are lacking and the relationship of temporal patterns in tree-ring δ15N to soil N dynamics is controversial. We examined whether the tree-ring δ15N of N2-fixing red alder (Alnus rubra Bong.) would mirror N accretion rates and δ15N of soils and whether the influence of alder-fixed N could be observed in the wood of a neighboring conifer. We sampled a 27-year-old replacement series trial on south-eastern Vancouver Island, with red alder and coastal Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) planted in five proportions (0/100, 11/89, 25/75, 50/50 and 100/0) at a uniform stem density. An escalation in forest floor N content was evident with an increasing proportion of red alder, equivalent to a difference of ~750 kg N ha−1 between 100% Douglas-fir versus 100% alder. The forest floor horizon also had high δ15N values in treatments with more red alder. Red alder had a consistent quadratic fit in tree-ring δ15N over time, with a net increase of |$\sim$| 1.5‰, on average, from initial values, followed by a plateau or slight decline. Douglas-fir tree-ring δ15N, in contrast, was largely unchanged over time (in three of four plots) but was significantly higher in the 50/50 mix. The minor differences in current leaf litter N content and δ15N between alder and Douglas-fir, coupled with declining growth in red alder, suggests the plateau or declining trend in alder tree-ring δ15N could coincide with lower N2-fixation rates, potentially by loss in alder vigor at canopy closure, or down-regulation via nitrate availability. [ABSTRACT FROM AUTHOR]

Through the application of the Douglas Fir Group's transdisciplinary framework, this study investigated how three levels of mutually dependent influence (i.e., the micro level of social action and interaction, meso level of sociocultural institutions and communities, and macro level of ideological structures) operate across time and space to shape a bilingual heritage language learner's study‐abroad (SA) experiences. Data were collected from standardized proficiency tests; language contact profiles; pre‐ and midprogram surveys; and interviews with the learner, classroom instructors, tutor–roommates, host family members, and the director of the SA program. The transdisciplinary framework enabled this study to expand its research focus and analytical scope, demonstrating that language learning was mediated by the three levels of mutually dependent influence in a dynamic and complex manner. This study has generated a richer understanding of multilayered complexity in heritage language development, advanced bilingual performance and proficiency, and bilingualism in language education and society. [ABSTRACT FROM AUTHOR]

Intraspecific macromolecule variation in stemwood, knotwood, and branchwood was studied using analytical pyrolysis with the intention of introducing a rapid working method to assess the variance in lignin content using analytical pyrolysis and highlight variability markers. The study was performed on Picea abies, Abies alba, and Pseudotsuga menziesii. Lignin determined via analytical pyrolysis–GC/MS (Py-lignin) can be used to identify variations in lignin content, compared to using classical Klason lignin values as a reference method for lignin determination, which requires a correction factor. Principal component analysis (PCA) was performed to identify biopolymer pyrolysis product markers for different species, tissues, or heights that could help highlight structural differences. Douglas fir was differentiated from spruce and silver fir in the levoglucosan amount. Guaiacol was more present in spruce wood, and creosol was more present in Douglas fir. Knotwood was structurally close to stemwood in spruce and silver fir, but there was a clear transition between stemwood and branchwood tissue in Douglas fir. Knotwood was differentiated by higher furan compounds. Branchwood was clearly separate from stemwood and knotwood and presented the same markers as compression wood in the form of phenylpropanoid lignins (H-lignin) as well as isoeugenol and vinyl guaiacol, the two most produced lignin pyrolysis products. [ABSTRACT FROM AUTHOR]

This paper addresses the problem of timber board positioning within the log where they were sawn from. The method takes as input log and board end cross-section images. It uses a two-step image matching method based on scale invariant feature transform and normalized correlation coefficient (NCC). In the first step, the scale factor and rotation angle of board end images are estimated from the board images that are correctly identified on the log end image by SIFT. Then, the accurate position of each board within the log end image is achieved by the NCC method. The method has been tested on 70 different log images and the 798 corresponding board images of various visual aspects and coming from three different species (Douglas fir, Norway spruce, and oak). The results fully demonstrate that the proposed method is not only rotation and scale invariant, but also has high accuracy properties. [ABSTRACT FROM AUTHOR]

Field-based learning is central to education in the biogeosciences, but COVID-19 and perennial challenges of large classes, short class times, and crowded schedules make exploration of alternative tools for field education more urgent than ever. Augmented reality (AR) is one candidate, allowing students to visit sites on their own time using a mobile app that guides them through a field trip via geolocationally triggered audio, images, and other media. Research into AR's pedagogical effectiveness is in its infancy, seldom directly comparing delivery of the same field learning activity via AR versus in person, or investigating AR's pedagogical value beyond the cognitive domain. To address this gap, we developed an AR version of an existing forest ecology field trip to a Douglas fir forest remnant in Vancouver, British Columbia, in a large undergraduate biogeoscience course, and compared student experiences of both versions. The study showed that AR can overcome obstacles to effective field education in large courses and deliver significant pedagogical benefits compared to conventional field trips, including engagement, enjoyment, flexibility, accessibility, and learning supports. With effective instructions and technological contingency planning, AR can be an effective tool for geoscientific field education and help address some larger pedagogical issues facing higher education. [ABSTRACT FROM AUTHOR]

The Douglas fir (Pseudotsuga menziesii) is a conifer native to North America that has become increasingly popular in plantations in France due to its many advantages as timber: rapid growth, quality wood, and good adaptation to climate change. Tree genetic improvement programs require knowledge of a species' genetic structure and history and the development of genetic markers. The very slow progress in this field, for Douglas fir as well as the entire genus Pinus, can be explained using the very large size of their genomes, as well as by the presence of numerous highly repeated sequences. Proteomics, therefore, provides a powerful way to access genomic information of otherwise challenging species. Here, we present the first Douglas fir proteomes acquired using nLC-MS/MS from 12 different plant organs or tissues. We identified 3975 different proteins and quantified 3462 of them, then examined the distribution of specific proteins across plant organs/tissues and their implications in various molecular processes. As the first large proteomic study of a resinous tree species with organ-specific profiling, this short note provides an important foundation for future genomic annotations of conifers and other trees. [ABSTRACT FROM AUTHOR]

The extractive contents of three softwood species largely used in the wood industry, namely Abies alba (Silver fir), Picea abies (spruce) and Pseudotsuga menziesii (Douglas fir), have been determined quantitatively for knots and at different points chosen along their branches, before analysis using high-performance liquid chromatography coupled with Mass Spectrometry (HPLC-MS). The results indicated that branchwood samples located in close proximity to the stem present high contents of extractives similar to those recorded for the knots. HPLC analysis showed quite similar chemical compositions, indicating that first cm of the branches could be considered as an additional source of knotwood. The antibacterial, antifungal and antioxidant activities of knot's extractives have been investigated with the dual objective of better understanding the role of high levels of secondary metabolites present in the knot and evaluating their potential for biorefinery applications. The antioxidant activity study showed that crude extracts of Douglas fir knotwood presented higher radical scavenging activity levels than the extracts of Silver fir and spruce, which presented more or less the same activities. Silver fir and spruce knotwood extracts presented higher antibacterial activity levels than the Douglas fir knotwood extracts did, while Douglas fir knotwood extracts presented more fungal growth inhibition than the spruce and fir knotwood extracts did. The structure–activity relationships indicate that radical scavenging and antifungal activities are associated with a higher relative quantity of flavonoids in the crude extracts, while higher relative quantities of lignans are associated with antibacterial activity. [ABSTRACT FROM AUTHOR]

To further understand calicioid communities and their habitat and substrate requirements, we conducted a study on the Colville National Forest of northeastern Washington State, U.S.A. We hypothesized that calicioid composition would vary depending on age and type of substrate, and that species diversity would be higher on older trees and in older stands, as found by previous research. To test these hypotheses, we searched for calicioids on plots established by the USDA Forest Service's Forest Inventory and Analysis (FIA) program. Because individual trees on FIA plots are tagged, we could relate recorded tree species and age to calicioid composition. We investigated calicioid species diversity in relation to host species; live, dead or burnt trees; and dominant forest type. Our analyses show that calicioid abundance and diversity do increase with tree age. Thuja plicata hosted the highest number of calicioid species in our study and also had the highest rate of occupancy with 70% of all investigated boles inhabited. In an analysis of the effect of forest type (series), we found the Thuja plicata series to host the highest number of species while the Pseudotsuga menziesii series had the lowest number of species. Only 3.4% of burnt trees sampled hosted calicioids while 43.6% of unburnt trees did, suggesting that fire does negatively impact calicioid communities. Three species, Chaenotheca obscura, Chaenothecopsis haematopus, and C. nigra and were found only on snags. Of the 17 species of shrubs sampled, only Alnus, Amelanchier, Salix, and Holodiscus hosted calicioid lichen or fungi. Species that have rarely been reported from Washington include Chaenothecopsis haematopus and C. ochroleuca. [ABSTRACT FROM AUTHOR]

Climate change poses severe pressures to European conifer forests. Using non‐native tree species, such as Douglas fir (Pseudotsuga menziesii), is one proposed strategy to circumvent adverse effects for forest management. However, novel forest health risks can impair the cultivation of non‐native trees. In 2022, we observed large Douglas fir trees (approximately 40–50 years old, diameter at breast height (dbh) 21–41 cm) that had recently died in spring or summer 2022 in three forest stands in Eastern Austria. Intensive resin flow, blue‐staining of the sapwood and the absence of bark‐ and wood‐boring insects indicated a fungal infection. Isolations from blue‐stained sapwood of the dead trees consistently yielded cultures of the opportunistic pathogen Diplodia sapinea. In a greenhouse wound inoculation experiment, seven D. sapinea isolates obtained from Douglas fir caused phloem necrosis, blue‐staining of sapwood and mortality and thus displayed pathogenicity towards seedlings of both Ps. menziesii and its common host, Scots pine (Pinus sylvestris). Diplodia sapinea produced significantly longer areas of blue‐stain as well as higher and faster mortality in Ps. menziesii compared to P. sylvestris. We conclude that D. sapinea substantially contributed to the death of seven of the 13 examined large Douglas fir trees. While this fungus has been described as a pathogen of young Douglas fir trees before, this is the first report that it can potentially kill large individuals of this conifer species under drought conditions. Thus, our results indicate that D. sapinea could represent a severe threat to the cultivation of Ps. menziesii in European forestry. [ABSTRACT FROM AUTHOR]

Fire is a major cause of tree injury and mortality worldwide, yet our current understanding of fire effects is largely based on ocular estimates of stem charring and foliage discoloration, which are error prone and provide little information on underlying tree function. Accurate quantification of physiological performance is a research and forest management need, given that declining performance could help identify mechanisms of—and serve as an early warning sign for—mortality. Many previous efforts have been hampered by the inability to quantify the heat flux that a tree experiences during a fire, given its highly variable nature in space and time. In this study, we used a dose–response approach to elucidate fire impacts by subjecting Pinus monticola var. minima Lemmon and Pseudotsuga menziesii (Mirb.) Franco var. glauca (Beissn.) Franco saplings to surface fires of varying intensity doses and measuring short-term post-fire physiological performance in photosynthetic rate and chlorophyll fluorescence. We also evaluated the ability of spectral reflectance indices to quantify change in physiological performance at the individual tree crown and stand scales. Although physiological performance in both P. monticola and P. menziesii declined with increasing fire intensity, P. monticola maintained a greater photosynthetic rate and higher chlorophyll fluorescence at higher doses, for longer after the fire. Pinus monticola also had complete survival at lower fire intensity doses, whereas P. menziesii had some mortality at all doses, implying higher fire resistance for P. monticola at this life stage. Generally, individual-scale spectral indices were more accurate at quantifying physiological performance than those acquired at the stand-scale. The Photochemical Reflectance Index outperformed other indices at quantifying photosynthesis and chlorophyll fluorescence, highlighting its potential use to quantify crown scale physiological performance. Spectral indices that incorporated near-infrared and shortwave infrared reflectance, such as the Normalized Burn Ratio, were accurate at characterizing stand-scale mortality. The results from this study were included in a conifer cross-comparison using physiology and mortality data from other dose–response studies. The comparison highlights the close evolutionary relationship between fire and species within the Pinus genus, assessed to date, given the high survivorship of Pinus species at lower fire intensities versus other conifers. [ABSTRACT FROM AUTHOR]

Our knowledge of the endophytic fungal community associated with needles of Sitka spruce (Picea sitchensis) is rather limited, which contrasts with the importance of this tree species for forestry in the UK. In our study, we focused on the detailed characterization of multiple isolates tentatively placed into the genera Nothophaeocryptopus and Rhizosphaera that were obtained from needles of Sitka spruce and co‐occurring Norway spruce (Picea abies) and Douglas fir (Pseudotsuga menziesii) at four sites in Scotland and Wales. After a thorough analysis of their phenotype and analysis of two nuclear regions (ITS rDNA and gene for β‐tubulin), we propose two species new to science and one new combination. Nothophaeocryptopus piceae was isolated from healthy green or brown needles from spruces and is currently known only as a sterile culture, but the taxonomic novelty is well supported by host affinity and results of molecular data analysis. Rhizosphaera minteri may also be distinguished based on the combination of host and molecular data, but morphologically, it is similar to R. pini. Finally, Hormonema merioides and R. pseudotsugae are found to be conspecific and a new combination R. merioides is proposed following the phylogenetic placement of this species. Our study highlights the importance of multiple approaches used in the identification of microfungi associated with coniferous needles. It is evident that morphologically identical fungi may represent distinct species differing in their host range and severity on the host. This study also provides a basis for future monitoring of these fungi associated with important coniferous forestry trees in the UK. [ABSTRACT FROM AUTHOR]

Calicium sperlingiae is described as new from Oregon, U.S.A. It was collected on the bark of Pseudotsuga menziesii on lands managed by the Bureau of Land Management, United States Department of the Interior. It is placed in Calicium based on morphology (stalked apothecia with black mazaedia and brown 2-celled, ellipsoidal ascospores) and molecular data. Phylogenetic relationships are inferred using the ITS region. The species is characterized by its superficial and well-developed, grayish-white, granular to leprose thallus, I– apothecia, moderately white-pruinose mazaedia, and relatively short clavate asci. A key to the North American species of Calicium is provided. [ABSTRACT FROM AUTHOR]

The number of non-native invasive pests and pathogens has increased dramatically in recent years, with disastrous consequences for the health of forests worldwide. Multiple studies have shown that mixed forests may suffer less damage from insect pests than single species forest. This "associational resistance" can be notably explained by the fact that heterospecific neighbours make it more difficult for herbivores to locate and then exploit their host tree. However, the validity of these findings in the case of nonnative, invasive pests and pathogens remains to be demonstrated. In this study, we monitored over two hundred Douglas firs in pure and mixed plots of a tree diversity experiment to assess the damage from the non-native gall midge Contarinia pseudotsugae and the non-native needle cast Nothophaeocryptopus gaeumannii. The probability of Swiss needle-cast infection was lower in Douglas fir trees surrounded by heterospecific neighbours. Gall midge damage was lower on Douglas firs surrounded by taller neighbours, consistent with the hypothesis of reduced host Apparency. Douglas fir trees that were more damaged by C. pseudotsugae were also more often infected by N. gaeumannii. Our study thus provides partial support of the associational resistance hypothesis of mixed forests against exotic pests and pathogens. Promoting forest species diversity at the stand level could, therefore, offer interesting prospects for reducing the impact of biological invasions, especially those involving both pests and pathogens. [ABSTRACT FROM AUTHOR]

Bamboo is a fast-growing biobased building material with a high strength-to-weight ratio, and the combination of bamboo and wood provides an environmentally friendly alternative for building construction. A new type of laminated bamboo–timber composite column was proposed to improve the compressive performance of timber columns, which was expected to obtain better mechanical performance. Bamboo scrimber and Douglas fir were combined to form laminated bamboo–timber composite columns for the experimental study. Axial compression tests were carried out on 5 groups of 15 composite columns. The failure modes of the composite columns were assessed. The laws of axial displacement, lateral displacement, axial strain, ultimate bearing capacity and stiffness were analyzed. Finally, the bearing capacity of the composite columns was calculated by referring to the design specification for timber structures. The results indicated that the composite columns exhibited three failure characteristics. The ultimate bearing capacity and stiffness of the bamboo–timber composite columns increased with increasing amount of bamboo scrimber. The ultimate load of the bamboo–timber composite columns was increased by 23.0–94.6%, while the stiffness was increased by 9.1–38.4%. In addition, the bearing capacity of composite columns was calculated according to two standards. The experimental values of the bamboo–timber composite columns are in good agreement with the theoretical values, and the errors are within 8%. [ABSTRACT FROM AUTHOR]

This document is a poem titled "Trailer Park Psalm" by Ryler Dustin. The poem reflects on the experiences and lives of individuals living in a trailer park. It explores themes of resilience, community, and the challenges faced by the residents. The poem acknowledges the diverse perspectives and experiences of the individuals, highlighting their struggles and moments of strength. [Extracted from the article]

Removal of benzene is essential for human and environmental health because it has toxic and hazardous properties at various concentrations. Theseneed to be effectively eliminated with carbon-based adsorbents. PASACs, carbon-based adsorbents obtained from using the needles of Pseudotsuga menziesii, were produced by optimized HCl- and H2SO4-impregnated approaches. Regarding physicochemical structure, the optimized PASAC23 and PASAC35 with surface areas of 657 and 581 m2/g and total pore volumes of 0.36 and 0.32 cm3/g showed ideal temperatures of 800 °C. In order to investigate and compare internal benzene removal efficiency, PASAC23 and PASAC35 were studied separately. Initial concentrations were found to range from 5 to 500 mg/m3, and between 25 and 45 °C. The removal rate of benzene by PASAC23 and PASAC35 was 97 and 94% at low concentrations, respectively. While the highest capture amount for PASAC23 and PASAC35 was found to be at 25 °C with 141 and 116 mg/g, the adsorption capacity decreased to 102 and 90 mg/g at 45 °C. The holding capacity decreased between 22.41 and 27.66% due to increasing temperatures. After five cycles of PASAC23 and PASAC35 regeneration, we found that they could remove 62.37 and 58.46% of benzene, respectively. These results confirmed that PASAC23 is a promising environmentally adsorbent for effectively removing benzene with a competitive yield. [ABSTRACT FROM AUTHOR]

This study aimed to investigate how pre-steaming affects the drying times, final moisture contents (final MCs), and prevention of checking during the high-temperature and low-humidity drying process of boxed-heartwood Korean red pine (Pinus densiflora S. et Z.) and Douglas-fir (Pseudotsuga menziesii) with 20 × 20 cm and with 30 × 30 cm cross sections. Although average final MCs of the larger cross sections were slightly higher than those of smaller cross sections, all were over-dried between 3.3% and 8.1% MC, compared to the in-use moisture content for outdoor building materials. All the pre-steamed samples were only slightly defected by surface checks of 5 mm or less in width. The sample timbers with the 20 × 20 cm cross-sectional size were slightly defected by internal checking, whereas those with the 30 × 30 cm cross-sectional size were severely defected. However, there was no clear impact of pre-steaming time on the prevention of internal checking. [ABSTRACT FROM AUTHOR]