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The natural forests of south‐central Chile are known as world biodiversity hotspot. Due to increasing societal demands and certification commitments, a vast extension of these forests that was replaced by commercial exotic tree plantations is now to be restored. Given the magnitude of the area involved, large‐scale approaches based on natural regeneration require consideration. However, experimental evidence for this approach to restoration is lacking in different regions. We conducted a large‐scale replicated experiment to evaluate the response of natural regeneration of native tree species to different harvesting treatments (clearcut, strip‐cutting, and unharvested control) in 20‐year‐old Pinus radiata plantations. For 2 years, we monitored variations in (1) regeneration basal area (dRBA), (2) maximum sapling height (dMH), (3) frequency of free‐growing regeneration (dFGR), and (4) diversity of regenerating tree species. The harvesting treatment had significant effects on dRBA, dMH, and dFGR. The clearcuts showed the highest values of dRBA and dFGR of native species, but also, the highest dRBA of P. radiata regeneration. The strip‐cuttings showed the highest dMH of native species and the highest values of richness, Shannon, and Simpson diversity. Our results suggest that both clearcuts and strip‐cuttings facilitate natural regeneration. Although clearcuts may allow higher rates of natural regeneration establishment than strip‐cuttings, they require periodic control of P. radiata regeneration to prevent suppression of established native regeneration. Strip‐cuttings may require fewer management interventions and allow for higher initial species diversity, although with a potentially longer establishment period and higher risk of damage from residual P. radiata trees experiencing wind throw. [ABSTRACT FROM AUTHOR]

Many contaminated tailings throughout the world cause environmental and human-health related problems due to air and water drift. Tailing phytostabilization is a promising solution, but only certain plant species may tolerate and grow in these contaminated areas. We analyzed the chemical properties of a vegetated and unvegetated area in a tailing site in Central Chile. In addition, in the vegetated area we analyzed the metals content of roots, stems, and foliage in 41-years old plantations of Pinus radiata, Acacia dealbata, and Eucalyptus globulus (the only three species that survived from a total of 34 species planted), and determined height (H), and diameter at breast height (DBH). The results indicated that, except for pH, Se, Pb, and organic matter, all components (nutrients and metals) were two- to three- fold lower in the vegetated tailing compared to that of the unvegetated tailing. The analysis of plant tissues indicated that Cu was higher in the roots of P. radiata (2,073 mg kg−1) and lower in the stems of the same species (4.1 mg kg−1). However, the ability to take up and transport Cu to the shoots was higher in A. dealbata and lower in P. radiata (bioaccumulation factor of 0.19 and 0.06, respectively). Here we present results for the first long-term phytostabilization project of copper mine tailings in Chile. From the 34 native and exotic species established in 1980 in a mine tailing disposal site with 1,000 mg Cu kg−1, only the exotic Pinus radiata, Acacia dealbata and Eucalyptus globulus were able to survive and adapt to the tailing conditions the last 41 years. This corroborates their potential for the future phytostabilization of copper mine wastes. [ABSTRACT FROM AUTHOR]

Pine resin is a valuable non-wood forest product with an increasing interest in multiple industrial sectors. Resin-tapping activities also provide valuable ecosystem services in timber-oriented and highly productive pine forest of Atlantic regions, where little previous experience in resin-tapping is available. The objectives of this study were to determine the efficiency of different stimulant pastes and its variation with pine species, site conditions, seasonality and frequency of tapping interventions. We conducted parallel experiments using both conventional and micro-tapping techniques in mature pine stands in NW Spain. We tested four stimulants (control and Zeta, Cunningham and Salicylic pastes) and two groove frequencies (every 2 or 3 weeks). All stimulant pastes significantly increased resin yield compared to the control, being resin stimulation highly consistent across years, sites and species. In conventional resin tapping, resin yield was maximized with the Cunningham and Salicylic pastes while in micro-tapping Salicylic was the most outstanding stimulant treatment. According to the rapid decay of resin flow after wounding, total resin yield decreased with more spaced grooves. However, the reduction was low, and the global efficiency of the tapping operations are likely maximized with grooves applied every three weeks, which would allow increasing the number of tapped trees. Micro-tapping techniques were valuable for screening stimulant pastes and anticipating variation among sites in resin production. Altogether, the Salicylic paste is recommended, especially at the beginning of the resin campaign, when the effect of the pastes was maximized, and if tapping is conducted using closed atmospheres and containers. [ABSTRACT FROM AUTHOR]

In this study, the stress distribution within the cell wall layers and the microstructural response under high-intensity microwave (HIMW) treatment were investigated. Finite-element models were developed for both single tracheid and multicellular structures, considering the influence of the saturated vapour pressure. The findings showed uniform vapour pressure caused expansion and deformation of the tracheid layers, with the radial wall deforming slightly more than the tangential wall due to differences in microfibril angle (MFA) and elastic properties. Despite its thinness, the S3 layer, with a wide MFA, played a pivotal role in supporting the saturated vapour pressure within the cell lumen under HIMW treatment, effectively constraining lateral cell-wall deformation. In contrast, the S2 layer, being the thickest, exhibited lower lateral elasticity and sustained damage at the interfaces with the S3 and S1 layers during the expansion and recovery stages. The multicellular simulation demonstrated that earlywood cells experienced larger deformations than latewood cells and revealed a negative correlation between the cell-wall thickness and deformation. The simulation results were validated through the microscopic analysis of the wood topography after HIMW treatment. The findings of this study provide significant insights into understanding the microstructural deformation of wood under HIMW treatment. [ABSTRACT FROM AUTHOR]

The global proliferation of Pinus radiata, known for its rapid growth and wood density, has led to an environmental challenge—significant waste production, especially bark, without a clear valorization route. This waste poses ecological concerns, and despite the crucial role of forest resources in structural applications, their limited fire resistance requires the use of coatings. However, traditional coatings lack an eco-friendly footprint. Addressing this challenge, this study aims to develop an intumescent coating with tannins extracted from waste bark, offering a sustainable alternative. This not only repurposes waste on a global scale but also aligns with the imperative for environmentally friendly materials, contributing to sustainable practices in the construction and wood treatment industry. This study achieved an eco-friendly FRR15 (fire resistance ratio 15) fire resistance classification with a 15% equivalence of low-molecular-weight tannins, presenting a sustainable alternative to commercial products. Characterization showed low-molecular-weight tannins comparable to conventional charring agents, with high hydroxyl content and oil absorption, while high-molecular-weight tannins exhibited lower viability. A reference coating achieved FRR30 fire resistance, aligning with commercial strength. The mechanical properties of tannin-based coatings matched commercial standards, with increased abrasion resistance and adhesion and decreased flexibility. Intumescent coatings with higher tannin content significantly reduced wood substrate charring and mass loss in flame response assessments. [ABSTRACT FROM AUTHOR]

Abstract Background Fusarium circinatum is the causal agent of pine pitch canker disease, which affects Pinus species worldwide, causing significant economic and ecological losses. In Spain, two Pinus species are most affected by the pathogen; Pinus radiata is highly susceptible, while Pinus pinaster has shown moderate resistance. In F. circinatum-Pinus interactions, phytohormones are known to play a crucial role in plant defense. By comparing species with different degrees of susceptibility, we aimed to elucidate the fundamental mechanisms underlying resistance to the pathogen. For this purpose, we used an integrative approach by combining gene expression and metabolomic phytohormone analyses at 5 and 10 days post inoculation. Results Gene expression and metabolite phytohormone contents suggested that the moderate resistance of P. pinaster to F. circinatum is determined by the induction of phytohormone signaling and hormone rearrangement beginning at 5 dpi, when symptoms are still not visible. Jasmonic acid was the hormone that showed the greatest increase by 5 dpi, together with the active gibberellic acid 4 and the cytokinin dehydrozeatin; there was also an increase in abscisic acid and salicylic acid by 10 dpi. In contrast, P. radiata hormonal changes were delayed until 10 dpi, when symptoms were already visible; however, this increase was not as high as that in P. pinaster. Indeed, in P. radiata, no differences in jasmonic acid or salicylic acid production were found. Gene expression analysis supported the hormonal data, since the activation of genes related to phytohormone synthesis was observed earlier in P. pinaster than in the susceptible P. radiata. Conclusions We determine that the moderate resistance of P. pinaster to F. circinatum is in part a result of early and strong activation of plant phytohormone-based defense responses before symptoms become visible. We suggest that jasmonic acid signaling and production are strongly associated with F. circinatum resistance. In contrast, P. radiata susceptibility was attributed to a delayed response to the fungus at the moment when symptoms were visible. Our results contribute to a better understanding of the phytohormone-based defense mechanism involved in the Pinus-F. circinatum interactions and provide insight into the development of new strategies for disease mitigation.

Background: Fusarium circinatum is the causal agent of pine pitch canker disease, which affects Pinus species worldwide, causing significant economic and ecological losses. In Spain, two Pinus species are most affected by the pathogen; Pinus radiata is highly susceptible, while Pinus pinaster has shown moderate resistance. In F. circinatum-Pinus interactions, phytohormones are known to play a crucial role in plant defense. By comparing species with different degrees of susceptibility, we aimed to elucidate the fundamental mechanisms underlying resistance to the pathogen. For this purpose, we used an integrative approach by combining gene expression and metabolomic phytohormone analyses at 5 and 10 days post inoculation. Results: Gene expression and metabolite phytohormone contents suggested that the moderate resistance of P. pinaster to F. circinatum is determined by the induction of phytohormone signaling and hormone rearrangement beginning at 5 dpi, when symptoms are still not visible. Jasmonic acid was the hormone that showed the greatest increase by 5 dpi, together with the active gibberellic acid 4 and the cytokinin dehydrozeatin; there was also an increase in abscisic acid and salicylic acid by 10 dpi. In contrast, P. radiata hormonal changes were delayed until 10 dpi, when symptoms were already visible; however, this increase was not as high as that in P. pinaster. Indeed, in P. radiata, no differences in jasmonic acid or salicylic acid production were found. Gene expression analysis supported the hormonal data, since the activation of genes related to phytohormone synthesis was observed earlier in P. pinaster than in the susceptible P. radiata. Conclusions: We determine that the moderate resistance of P. pinaster to F. circinatum is in part a result of early and strong activation of plant phytohormone-based defense responses before symptoms become visible. We suggest that jasmonic acid signaling and production are strongly associated with F. circinatum resistance. In contrast, P. radiata susceptibility was attributed to a delayed response to the fungus at the moment when symptoms were visible. Our results contribute to a better understanding of the phytohormone-based defense mechanism involved in the Pinus-F. circinatum interactions and provide insight into the development of new strategies for disease mitigation. [ABSTRACT FROM AUTHOR]

Individual-tree-based models (IBMs) have emerged to provide finer-scale operational simulations of stand dynamics by accommodating and/or representing tree-to-tree interactions and competition. Like stand-level growth model development, IBMs need an array of detailed data from individual trees in any stand through repeated measurement. Conventionally, these data have been collected through forest mensuration by establishing permanent sample plots or temporary measurement plots. With the evolution of remote sensing technology, it is now possible to efficiently collect more detailed information reflecting the heterogeneity of the whole forest stand than before. Among many techniques, airborne laser scanning (ALS) has proved to be reliable and has been reported to have potential to provide unparallel input data for growth models. This study utilized repeated ALS data to develop a model to project the annualized individual tree height increment (ΔHT) in a conifer plantation by considering spatially explicit competition through a mixed-effects modelling approach. The ALS data acquisition showed statistical and biological consistency over time in terms of both response and important explanatory variables, with correlation coefficients ranging from 0.65 to 0.80. The height increment model had high precision (RMSE = 0.92) and minimal bias (0.03), respectively, for model fitting. Overall, the model showed high integrity with the current biological understanding of individual tree growth in a monospecific Pinus radiata plantation. The approach used in this study provided a robust model of annualized individual tree height growth, suggesting such an approach to modelling will be useful for future forest management. [ABSTRACT FROM AUTHOR]

A novel MADS-box transcription factor from Pinus radiata D. Don was characterized. PrMADS11 encodes a protein of 165 amino acids for a MADS-box transcription factor belonging to group II, related to the MIKC protein structure. PrMADS11 was differentially expressed in the stems of pine trees in response to 45° inclination at early times (1 h). Arabidopsis thaliana was stably transformed with a 35S::PrMADS11 construct in an effort to identify the putative targets of PrMADS11. A massive transcriptome analysis revealed 947 differentially expressed genes: 498 genes were up-regulated, and 449 genes were down-regulated due to the over-expression of PrMADS11. The gene ontology analysis highlighted a cell wall remodeling function among the differentially expressed genes, suggesting the active participation of cell wall modification required during the response to vertical stem loss. In addition, the phenylpropanoid pathway was also indicated as a PrMADS11 target, displaying a marked increment in the expression of the genes driven to the biosynthesis of monolignols. The EMSA assays confirmed that PrMADS11 interacts with CArG-box sequences. This TF modulates the gene expression of several molecular pathways, including other TFs, as well as the genes involved in cell wall remodeling. The increment in the lignin content and the genes involved in cell wall dynamics could be an indication of the key role of PrMADS11 in the response to trunk inclination. [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]

The goal of this study is to comprehensively evaluate the natural weathering performance of three wood species representing hardwood and softwood modified with the acetylation process. Alder (Alnus glutinosa L.), beech (Fagus sylvatica L.), and radiata pine (Pinus radiata D. Don) were characterised by various techniques to determine the aesthetical, chemical, and physical changes. The overall aesthetic performance of the investigated species was similar, with all showing a change in appearance after 9 months of exposure. However, the multi-sensor approach used for characterisation revealed differences in weathering behaviour related to surface erosion, wettability, and changes in chemical composition between the investigated species. An increase in the surface roughness observed for both hardwoods was associated with the erosion of the wood surface and the leaching of photodegraded chemical components. On the contrary, values of Sa remained relatively constant for acetylated radiata pine. Acetylated pine wood exhibited lower susceptibility to bleaching at the initial stage of the weathering process (3 months) and represented a more constant CIE L* compared to the investigated hardwood species. The contact angle measured with water gradually decreased in the case of acetylated radiata pine for up to six months, then it plateaued with a slight oscillation around 15°. For both hardwood species, the big drop was observed already after three months, followed by rather similar values. The PCA of IR spectra highlighted different mechanisms in the weathering of acetylated softwood and hardwood. The acetylated hardwood samples showed higher thermal stability than acetylated radiata pine. Experimental findings provide a comprehensive understanding of the long-term performance of acetylated wood, which directly influences its practical applications by enhancing design strategies, maintenance planning, product development, market acceptance, and overall sustainability. Performed tests have demonstrated the potential of underutilised hardwood species, enhanced through the acetylation process, to serve as alternative cladding materials to commonly used acetylated radiata pine. [ABSTRACT FROM AUTHOR]

The porosity of cell walls, as indicated by diffusion of rhodamine B dye, in the wood of Douglas fir, radiata pine, New Zealand red beech and Shining gum was compared under dynamic conditions using fluorescence recovery after photobleaching. The comparative diffusion rate was estimated using the half-life of fluorescence recovery under water-saturated conditions performed on transverse sections. All four wood species showed similar diffusion behaviour in tracheid or fibre cell walls with slower diffusion in the middle lamella layer compared to the secondary cell wall. Within the S2 layer of the secondary wall two regions were observed, an outer region with a slow diffusion rate and an inner region with a higher diffusion rate. Vessel cell walls showed slightly slower diffusion rates. Diffusion of rhodamine B dye appears to occur primarily along the fibre axis and is probably somewhat different to water in its behaviour. This suggests that pores are aligned with cellulose microfibrils. The dye diffusion rate was estimated to be in the range of 50–100 nm2 s−1. This has implications for understanding wood drying behaviour and chemical modification of wood by infiltration with small molecules as well as water storage in living trees. [ABSTRACT FROM AUTHOR]

Softwood is widely employed in construction and faces high demand. Australia is grappling with substantial timber scarcity, specifically related to radiata pine, which is the dominant structural timber in the construction sector. However, Australia has a significant hardwood population, which can be utilized to reduce the high demand for radiata pine. This paper aims to investigate the bond properties of both Australian softwood (radiata pine) and hardwood (shining gum). It also discusses the potential to combine softwood and hardwood in glue or cross-laminated timber by evaluating the bond properties of the radiata pine–shining gum interface. For hardwood, the effect of primer is also investigated to determine its efficacy in improving failure mode, bond strength, and stiffness. Lastly, both glulam and cross-laminated timber bonding scenarios are simulated for bond testing by examining the effect of relative fibre orientation on the bond properties of the aforementioned species individually and in combination. Instead of conventional block shear testing, which is predominantly used for same-species bond testing, push-out testing is adopted in this study. However, a comparison with block shear testing is also made in this article. The results indicated that the use of primer on hardwood reduced the inconsistencies in the bond properties and improved wood-side failure rates. It was also concluded that the effect of fibre orientation in a CLT scenario with combined hardwood and softwood failure modes can vary significantly, which leads to a higher standard deviation in the results. Nevertheless, this study outlines the challenges and opportunities for producing hardwood–softwood hybrid glue or cross-laminated timber. [ABSTRACT FROM AUTHOR]

This study explores the Hydrothermal Carbonization (HTC) treatment of lignocellulosic biomass blends, delving into the influence of several key parameters: temperature, additive nature and dosage, residence time, and biomass composition. Rapeseeds, Pinus radiata sawdust, oat husks, and pressed olive served as the studied biomasses. One hundred twenty-eight experiments were conducted to assess the effects on mass yield (MY), energy yield (EY), higher heating value (HHV), and final ash content (ASH) by a Factorial Experimental Design. The derived model equations demonstrated a robust fit to the experimental data, averaging an R2 exceeding 0.94, affirming their predictive accuracy. The observed energy yield ranged between 65% and 80%, notably with sawdust and olive blends securing EY levels surpassing 70%, while rapeseed blends exhibited the highest HHV at 25 MJ/kg. Temperature emerged as the most influential factor, resulting in an 11% decrease in MY and a substantial 2.20 MJ/kg increase in HHV. Contrastingly, blend composition and additive presence significantly impacted ASH and EY, with all blends exhibiting increased ASH in the presence of additives. Higher initial hemicellulose and aqueous extractive content in raw biomass correlated proportionally with heightened HHV. [ABSTRACT FROM AUTHOR]

Sustainable forest management is important to maintain the ability of forests to grow and provide a range of products and environmental services while retaining their natural features. We find that income, radiata pine prices, trade, agricultural expansion, and environmental policies have a significant impact on timber harvesting in New Zealand. Increase in income, radiata pine prices, number of farms, horticulture plantation and bank loans lead to an increase in timber harvesting. On the other hand, environmental policies, especially those to mitigate climate change, decrease timber harvesting. [ABSTRACT FROM AUTHOR]

How different stressors impact plant health and memory when they are imposed in different generations in wild ecosystems is still scarce. Here, we address how different environments shape heritable memory for the next generation in seeds and seedlings of Pinus radiata, a long‐lived species with economic interest. The performance of the seedlings belonging to two wild clonal subpopulations (optimal fertirrigation vs. slightly stressful conditions) was tested under heat stress through physiological profiling and comparative time‐series chloroplast proteomics. In addition, we explored the seeds conducting a physiological characterization and targeted transcriptomic profiling in both subpopulations. Our results showed differential responses between them, evidencing a cross‐stress transgenerational memory. Seedlings belonging to the stressed subpopulation retained key proteins related to Photosystem II, chloroplast‐to‐nucleus signalling and osmoprotection which helped to overcome the applied heat stress. The seeds also showed a differential gene expression profile for targeted genes and microRNAs, as well as an increased content of starch and secondary metabolites, molecules which showed potential interest as biomarkers for early selection of primed plants. Thus, these finds not only delve into transgenerational cross‐stress memory in trees, but also provide a new biotechnological tool for forest design. Summary statement: These results provide a deep knowledge of transgenerational cross‐stress priming in long‐lived species, revealing potential biomarkers for early selection of primmed seeds as a core strategy for designing climate‐smart forestry. [ABSTRACT FROM AUTHOR]

The bark of Pinus radiata offers an underutilized source of high-value renewable chemicals such as extractable polyphenols and lipophilic compounds (waxes and suberin). Here, the depolymerization and extraction of suberin from P. radiata bark and its repolymerization to form novel polyesters are reported. Three different strategies were evaluated for repolymerization of the suberin monomers, with starting materials and products characterized using chemical and thermal analysis techniques. The inclusion of comonomer (1,12-dodecanediol) to provide stoichiometric balance improved the conversion, product yield, solubility and increased molecular weight. Enzymatic polymerization conditions gave the highest yield, while the highest molecular weight was achieved using titanium butoxide, demonstrating that polymerization conditions could be varied to target desired product properties. Products were hydrophobic, as shown by contact angles, ϴ ≥ 90° after 30 s. This work highlights opportunities for utilizing suberin to add value to a P. radiata bark biorefinery concept. Potential future applications include its use as a starting material for novel bio-based polymers that can serve as water-repellent surfaces and coatings, replacing established products derived from fossil resources. [ABSTRACT FROM AUTHOR]

Forest plantations are economically and environmentally relevant, as they play a key role in timber production and carbon capture. It is expected that the future climate change scenario affects forest growth and modify the rotation age for timber production. However, mathematical models on the effect of climate change on the rotation age for timber production remain still limited. We aim to determine the optimal rotation age that maximizes the net economic benefit of timber volume in a negative scenario from the climatic point of view. For this purpose, a bioeconomic optimal control problem was formulated from a system of Ordinary Differential Equations (ODEs) governed by the state variables live biomass volume, intrinsic growth rate, and area affected by fire. Then, four control variables were associated to the system, representing forest management activities, which are felling, thinning, reforestation, and fire prevention. The existence of optimal control solutions was demonstrated, and the solutions of the optimal control problem were also characterized using Pontryagin’s Maximum Principle. The solutions of the model were approximated numerically by the Forward–Backward Sweep method. To validate the model, two scenarios were considered: a realistic scenario that represents current forestry activities for the exotic species Pinus radiata D. Don, and a pessimistic scenario, which considers environmental conditions conducive to a higher occurrence of forest fires. The optimal solution that maximizes the net benefit of timber volume consists of a strategy that considers all four control variables simultaneously. For felling and thinning, regardless of the scenario considered, the optimal strategy is to spend on both activities depending on the amount of biomass in the field. Similarly, for reforestation, the optimal strategy is to spend as the forest is harvested. In the case of fire prevention, in the realistic scenario, the optimal strategy consists of reducing the expenses in fire prevention because the incidence of fires is lower, whereas in the pessimistic scenario, the opposite is true. It is concluded that the optimal rotation age that maximizes the net economic benefit of timber volume in P. radiata plantations is 24 and 19 years for the realistic and pessimistic scenarios, respectively. This corroborates that the presence of fires influences the determination of the optimal rotation age, and as a consequence, the net economic benefit. [ABSTRACT FROM AUTHOR]

A cold-formed, thin-walled steel/fast-growing timber composite system has recently been presented for low-rise buildings. It aims to increase the use of fast-growing wood as a green building material in structures, thus contributing to the transformation of traditional buildings. This study proposed a composite I-beam combined with fast-growing radiata pine and cold-formed thin-walled U-shaped steel. A four-point bending test was used to measure the bending properties of steel–timber composite I-beams under various connection methods. Based on experimental results, this study examined the specimen's failure mechanism, mechanical properties, and strain development. In addition, a method for calculating flexural bearing capacity based on the superposition principle and transformed section method was suggested. It is evident from the results that fast-growing timber and cold-formed thin-walled steel can have significant composite effects. Different connecting methods significantly impact beams' failure mode, stiffness, and bearing capacity. Furthermore, the theoretical method for calculating the flexural bearing capacity of composite beams differs from the test value by less than 10%. This paper's research encourages the applications of fast-growing wood as light residential components, and it serves as a reference for the development, production, and engineering of steel–timber composite structural systems. [ABSTRACT FROM AUTHOR]

Radiata pine is one of the most commonly planted tree species in Chile due to its fast growth and desirable wood and pulp properties. However, its productivity is hampered by several diseases. Pitch canker disease (PCC) caused by Fusarium circinatum, is considered the most damaging disease to the pine forest industry. Several control measures have been established, with biological control emerging as an environmentally friendly and effective way for F. circinatum control. Previous studies support the value of Clonostachys rosea in reducing PCC damage, with evidence suggesting a potential induced systemic resistance (ISR) triggered in radiata pines by this agent. Ten-month-old radiata pine plants were pre-treated with C. rosea on a substrate at 8 and 1 days before inoculation with F. circinatum on the stem tip, and expression levels were determined for DXS1, LOX, PAL, and PR3 genes 24 h later. Lesion length was 45% lower on plants pre-treated with C. rosea and infected with F. circinatum compared to non-pre-treated and infected plants. Additionally, LOX and PR3 were induced 23 and 62 times more, respectively, in comparison to untreated plants. Our results indicate that C. rosea causes an ISR response in pre-treated plants, significantly increasing the expression of resistance genes and reducing lesion length. [ABSTRACT FROM AUTHOR]

A root disease in plantations of Pinus radiata and Pinus pinaster, where trees died in distinct patches, was present in the Western Cape province of South Africa during the 1970s and 1980s. Phytophthora cinnamomi was initially believed to be the cause, but the disease was later ascribed to the insect-associated fungus Leptographium serpens, a fungal species residing in the Ophiostomatales. Doubt regarding the cause of the disease was raised in a later study due to the fact that most Leptographium spp., particularly those that colonise ray parenchyma tissues, which is the case for L. serpens, are not typically primary disease agents. In this study, cultures of an unidentified sterile fungus collected from the dying trees were revived and identified using DNA sequencing methods, which were not available when the disease was first studied. These cultures were identified as the pyrophillic pathogen Rhizina undulata, well-known to cause patch death of conifers in South Africa and elsewhere in the world. While the patches of dying trees no longer exist and the disease cannot be newly studied, it is most likely that the tree death originally thought to be caused by L. serpens was due primarily to R. undulata. The study provides a vivid example of the value of preserving cultures of fungi for later study and the power of modern techniques to identify fungal pathogens. [ABSTRACT FROM AUTHOR]

Given increasing forest disturbances, novel solutions are needed to rapidly recover ecosystem services such as carbon storage, while bolstering climate change adaptation. Reforestation with single-species mixed-provenance plantings is an emerging strategy that may enhance stand productivity and disturbance resistance, while assisted gene flow is a potentially powerful tool for matching seed-source with future planting-site climate. We investigated the potential of mixed-provenance plantings and assisted gene flow for maximizing early growth using a historical dataset for knobcone-Monterey pine (Pinus x attenuradiata), a fire-resilient hybrid developed for low-elevation sites in California, USA. We examined (1) 9-year individual-tree relative growth rate (RGR) in response to neighborhood seed-parent provenance diversity at two test sites and (2) 3-year RGR and survival as functions of parent seed-source climate at 4 test sites. We found 9-year RGR varied with seed provenance diversity, with 3 of 5 provenances showing a positive RGR-diversity relationship. Parent seed-source climate affected 3-year RGR but not survival. Closer climate matches in terms of precipitation as snow (PAS) showed fastest growth. Our results suggest careful selection and arrangement of genetically diverse stock may improve carbon sequestration and initial planting success in a hybrid conifer, with implications for reforestation under climate change and reburn risk. [ABSTRACT FROM AUTHOR]

Red needle cast (RNC), mainly caused by Phytophthora pluvialis, is a very damaging disease of the widely grown species radiata pine within New Zealand. Using a combination of satellite imagery and weather data, a novel methodology was developed to pre-visually predict the incidence of RNC on radiata pine within the Gisborne region of New Zealand over a five-year period from 2019 to 2023. Sentinel-2 satellite imagery was used to classify areas within the region as being disease-free or showing RNC expression from the difference in the red/green index (R/Gdiff) during a disease-free time of the year and the time of maximum disease expression in the upper canopy (early spring–September). Within these two classes, 1976 plots were extracted, and a classification model was used to predict disease incidence from mean monthly weather data for key variables during the 11 months prior to disease expression. The variables in the final random forest model included solar radiation, relative humidity, rainfall, and the maximum air temperature recorded during mid–late summer, which provided a pre-visual prediction of the disease 7–8 months before its peak expression. Using a hold-out test dataset, the final random forest model had an accuracy of 89% and an F1 score of 0.89. This approach can be used to mitigate the impact of RNC by focusing on early surveillance and treatment measures. [ABSTRACT FROM AUTHOR]

In the coastal mountain range of the Maule region, 23 ravine rain forests dominated by canelo (Drimys winteri) and various native myrtaceae species were described in phytosociological terms in a study published in 1988. In this study, 20 of these forests were located again thirty years later to document their current situation in a context of successive anthropogenic impacts and climate change. The objectives of this study are to characterize changes in plant composition using the modified Braun-Blanquet phytosociological method, evaluate changes in soil occupation through comparative analysis of Landsat images from 1987, 2003 and 2017, and examine the natural regeneration of woody species inside and outside ravine forests. The results showed that between 1987 and 2017, the area occupied by native forest in the study area was reduced by 72 %. The importance and presence of representative species, such as Drimys winteri and Blechnum chilense reported in the original inventories, decreased, and sclerophyllous species, like Lithrea caustica and Cryptocarya alba, entered, along with introduced species, like Pinus radiata and Teline monspessulana. The regeneration of native trees and native creeping and climbing species was higher inside the ravine forests, while the germination of native shrubs was higher at their edges. The modification of the surrounding matrix of forests due to increased anthropic pressure and an advance of stressful conditions explains the observed changes. [ABSTRACT FROM AUTHOR]

This is a review of studies related with the effects generated by the fast-growing exotic plantations (PECR) of Pinus radiata and Eucalyptus spp. on water quality of watersheds in south-central Chile, at different spatial and temporal scales. The analyzed data comes from a region between 36° - 40° S in the Central Valley and includes both mountain ranges, the Coastal and the Andes. Studies on the watershed's capacity to export nutrients indicate that the conversion from native forests to forest plantations implies a net loss in nitrogen (N) and phosphorus (P) retention capacity. Consequently, watersheds with plantations coverage experience a net loss of these nutrients. Similarly, in watersheds dominated by Eucalyptus globulus, nitrogen retention decreases, especially NO3-N, and is partially reversed as a wider riparian vegetation is maintained. Studies of soil erosion and sediment transport losses show that clearcut harvesting has significant impacts on water quality, increasing sediment transport rates in streams. However, when soil conservation measures are practiced, erosion rates decrease significantly during forest harvesting. Some of the physical-chemical characteristics of the water, such as pH and temperature, are similar between streams with native forests and forest plantations. There is also a tendency for a decrease of richness and abundance of the macrobenthic invertebrates community due to the replacement of riparian vegetation by Eucalyptus spp. [ABSTRACT FROM AUTHOR]

Effective long-term management of invasive non-native species (INNS) in South America is a pressing yet complex task. Critically, the environmental, historical, cultural, and economic idiosyncrasies of the region call for the inclusion of a plurality of views from those sectors of society receiving the negative and positive impacts of INNS. This is a multifaceted, and often daunting, task that can be aided by an early identification of stakeholders – those affected by or with an interest in INNS and their management – accompanied by targeted stakeholder engagement. Here, we report the procedures and results of a stakeholder mapping activity aimed at identifying stakeholders and designing engagement strategies. Using expert knowledge procedures, we compiled comprehensive lists of stakeholders for six case-studies in South America: (i) invasive grasses (Urochloa spp.) in Brazil; (ii) glossy privet (Ligustrum lucidum) in Argentina; (iii) lodgepole and Monterey pines (Pinus contorta and P. radiata) in Argentina; (iv) American mink (Neogale vison) in Argentina and Chile; (v) lodgepole and Monterey pines in Chile; and (vi) German yellow-jacket (Vespula germanica) in Chile. Overall, we identified 250 stakeholders, which, based on their interest and influence, were classified into "context settlers" (2%), "key players" (47%), "crowd" (5%), and "subjects" (49%). We outlined strategies to engage with each of these four groups and for each of our six case-studies. Across case studies, communication with stakeholders was the most common engagement strategy proposed (27%; 19 of 70 strategies), followed by active involvement of stakeholders in INNS research and management (23%). Our results highlight the importance of considering power imbalances, as those stakeholders more likely to benefit from INNS were assessed to have more influence over INNS management relative to local and indigenous communities. Our work illustrates how to identify stakeholders in a rigorous and rapid manner, which should be complemented with the involvement of the stakeholders themselves. [ABSTRACT FROM AUTHOR]

Chemical modification is an efficient strategy for improving wood quality; however, for some fast-grown wood species unwanted shrinkage occur upon treatment with alkaline solution. This study was devised to reveal the shrinkage behavior of poplar and radiata pine woods treated with 5, 10, 15 and 20 % alkaline sodium silicate (SS) solutions. Wood treated with sodium hydroxide (SH) solution adjusting to the same pH as the specific SS solution was used as a reference sample. The weight loss, chemical components analysis, and confocal microscopy revealed that treatments with SS caused considerable reductions in hemicellulose and acid-insoluble lignin (AIL) of poplar wood up to 51 % and 21 %, respectively. In contrast, such reductions of the SS-treated radiata pine wood were only 13 % and 2 %, respectively. Consequently, shrinkage of poplar wood in the tangential- and radial-directions reached up to 22 % and 11 % respectively. However, such shrinkage for radiata pine was less than 2 % in either direction. The crystallinity index of poplar and radiata pine woods after treatment increased up to 35.3 % and 4.8 %, respectively, attributable to removal of the amorphous fraction. The scanning electron microscopy displayed that treatments had minor effect on the cell structure of radiata pine, but brought about significant collapse of poplar cells. The above results show that radiata pine is more chemically stable to alkaline treatment than poplar. [ABSTRACT FROM AUTHOR]

The IML PD series Resi is a device used to assess the drilling resistance of wood. The IML PD series Resi instrument is being widely adopted for commercial wood quality assessment due to its speed, cost-effectiveness, and precision when combined with web-based trace processing. Collecting Resi data with fixed feed speed and RPM settings is challenging due to inherent basic density variations within and between tree species. Altering these settings affects the drilling resistance amplitude of the Resi data, impacting basic density predictions. This study introduces the concept of chip thickness to combine feed speed and RPM into a single parameter to minimise the effects of different sampling conditions on the basic density predictions. Regression models, with chip thickness as the regressor variable, account for 97% to 99% of variance in mean Resi outerwood amplitude across six species. The demonstrated adaptability of chip thickness for adjusting feed speed and RPM settings, along with species-specific functions correlating it with Resi amplitude, holds promise for standardizing amplitude values across diverse feed speeds and RPM settings. Optimal sampling conditions needed to predict basic density lie within the 30%–40% amplitude range. To drill a ~30 cm diameter tree, the recommended fastest settings were 200 cm/min and 3500 RPM for Southern Pine (Pinus elliottii var. elliottii (Engelm) × Pinus caribaea var. hondurensis (Sénéclauze)) and Radiata Pine (Pinus radiata (D. Don.)), 200 cm/min and 2500 RPM for Hoop Pine (Araucaria cunninghamii (Mudie)), 50 cm/min and 5000 RPM for Spotted Gum (Corymbia citriodora subsp. variegata (F. Muell.)), 200 cm/min and 4500 RPM for White Cypress (Callitris glaucophylla (Thompson & Johnson)), and 150 cm/min and 3500 RPM for Shining Gum (Eucalyptus nitens (H. Deane & Maiden) Maiden) based on the billets sampled. [ABSTRACT FROM AUTHOR]

The use of endoglucanase enzymes as pretreatment of high-yield pulps to produce lignocellulose nanofibrils (LCNFs) has garnered increasing interest at both industrial and scientific levels. However, the lignin present in the lignocellulosic fibers hinders the enzymatic treatment reducing the efficiency of the further fibrillation process. This work postulates that modifying the structure of the residual lignin in the pulp can help to improve LCNF production. Laccase-mediator system (LMS) was evaluated to promote lignin oxidation of pressurized groundwood pulp from Pinus radiata previous to a treatment with endoglucanases and mechanical refining to produce LCNFs. As a result, it was observed that the LMS treatment improved the accessibility of the endoglucanase enzyme in the fibers, increasing their efficiency. Furthermore, it was observed a reduction in residual lignin and an increment in acidic groups in the LMS treated pulps facilitated the mechanical fibrillation process, enabling the production of LCNFs with a high aspect ratio. It was also observed that the pulps treated with a laccase-endoglucanase combination allowed to production of LCNF suspensions with zeta potential values sufficient for the nanofibrils not to form aggregates and to be considered stable (< − 25 mV). [ABSTRACT FROM AUTHOR]

Applying stress factors such as high temperatures during the different stages of somatic embryogenesis is important to uncover the molecular mechanisms of stress response and adaptation, and as a strategy to produce plants adapted to harsh environmental conditions derived from climate changes. In this sense, the present work aims to study the effect of high temperatures applied during the maturation of somatic embryogenesis in the ploidy stability, the amino acid and polyamine profiles of the somatic embryos obtained, and the morphological characteristics of the somatic plantlets. The results revealed that the maturation temperature did not affect the morphology of the resulting somatic plantlets, nor the ploidy and genome size of phenotypically normal somatic embryos, whose ploidy and DNA content levels were similar to those found in mature zygotic embryos. Nonetheless, a slight but significant reduction of the genome size of aberrant somatic embryos was observed. The maturation temperature changed the levels of glycine, arginine, lysine, and ornithine. These last three amino acids are precursors of the polyamines detected. Regarding this, putrescine levels were higher in somatic embryos from the highest maturation temperature (5 min pulse at 60 ºC), however, the amount of this polyamine in all samples was much lower than spermidine, spermine and cadaverine. In conclusion, the different temperatures applied did not lead to substantial changes in the ploidy level, endogenous PAs of the somatic embryos developed, or in the morphology of the somatic plantlets. Significant changes in the endogenous amino acids were observed, which may be linked to PAs metabolism and other metabolic pathways involved in stress response. Key message: Maturation temperature doesn´t affect ploidy levels of radiata pine somatic embryos, however, it affects the endogenous levels of glycine, arginine, lysine, and putrescine. [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]

This study aimed to explore alternative substrates for growing forest species using eucalyptus bark. It evaluated the potential of extracted Eucalyptus globulus fiber bark as a substitute for commercial growing media such as coconut fiber, moss, peat, and compost pine. We determined the physicochemical parameters of the growing media, the germination rate, and the mean fresh and dry weights of seedlings. We used the Munoo-Liisa Vitality Index (MLVI) test to evaluate the phytotoxicity of the bark alone and when mixed with commercial substrates. Generally, the best mixture for seed growth was 75% extracted eucalyptus bark fiber and 25% commercial substrates. In particular, the 75E-25P (peat) mixture is a promising substitute for seedling growth of Pinus radiata, achieving up to 3-times higher MLVI than the control peat alone. For Quillaja saponaria, the best growth substrate was the 50E-50C (coconut fiber) mixture, which had the most significant MLVI values (127%). We added chitosan and alginate-encapsulated fulvic acid phytostimulants to improve the performance of the substrate mixtures. The fulvic acid, encapsulated or not, significantly improved MLVI values in Q. saponaria species and P. radiata in concentrations between 0.05 and 0.1% w/v. This study suggests that mixtures with higher levels of extracted fiber are suitable for growing forest species, thus promoting the application of circular economy principles in forestry. [ABSTRACT FROM AUTHOR]

In commercial forestry and large-scale plant propagation, the utilization of artificial intelligence techniques for automated somatic embryo analysis has emerged as a highly valuable tool. Notably, image segmentation plays a key role in the automated assessment of mature somatic embryos. However, to date, the application of Convolutional Neural Networks (CNNs) for segmentation of mature somatic embryos remains unexplored. In this study, we present a novel application of CNNs for delineating mature somatic conifer embryos from background and residual proliferating embryogenic tissue and differentiating various morphological regions within the embryos. A semantic segmentation CNN was trained to assign pixels to cotyledon, hypocotyl, and background regions, while an instance segmentation network was trained to detect individual cotyledons for automated counting. The main dataset comprised 275 high-resolution microscopic images of mature Pinus radiata somatic embryos, with 42 images reserved for testing and validation sets. The evaluation of different segmentation methods revealed that semantic segmentation achieved the highest performance averaged across classes, achieving F1 scores of 0.929 and 0.932, with IoU scores of 0.867 and 0.872 for the cotyledon and hypocotyl regions respectively. The instance segmentation approach demonstrated proficiency in accurate detection and counting of the number of cotyledons, as indicated by a mean squared error (MSE) of 0.79 and mean absolute error (MAE) of 0.60. The findings highlight the efficacy of neural network-based methods in accurately segmenting somatic embryos and delineating individual morphological parts, providing additional information compared to previous segmentation techniques. This opens avenues for further analysis, including quantification of morphological characteristics in each region, enabling the identification of features of desirable embryos in large-scale production systems. These advancements contribute to the improvement of automated somatic embryogenesis systems, facilitating efficient and reliable plant propagation for commercial forestry applications. [ABSTRACT FROM AUTHOR]

Woodlands subjected to commercial exploitation can play an important role in the conservation of forest-dwelling birds, whether these species breed, forage, or spend all or part of their annual cycle in this habitat. Since 2016, the Administration of Gipuzkoa Province, Spain, has implemented a new protocol designed to preserve the nesting habitat of the Red Kite (Milvus milvus) population breeding within the region. This species is locally classified as endangered and therefore has conservation priority. The aim of our study was to evaluate the efficacy, demographic impact, and cost of this protocol. Over a period of 7 yr (2016–2022), implementation of the protocol preserved 23 nests (i.e., 15.2% of the total 151 nests). From these protected nests, 37 young fledged, which was 16% of all the young fledged within the region in this period. Relative to the financial cost of protecting nature in Gipuzkoa, implementation of this protocol was inexpensive, totalling <0.1% of the administration's budget for managing natural habitats within the province. Los bosques sometidos a explotación comercial pueden desempeñar un papel importante en la conservación de aves que habitan en ellos y se reproducen, forrajean o pasan todo o parte de su ciclo anual allí. Desde 2016, la Administración de la Provincia de Gipuzkoa, España, ha diseñado e implementado un nuevo protocolo con el fin de preservar el hábitat de nidificación de la población de Milvus milvus que se reproduce en la región, ya que esta especie está clasificada como localmente en peligro de extinción y, por lo tanto, tiene prioridad de conservación. El objetivo de nuestro estudio fue evaluar la eficacia, el impacto demográfico y el costo de este protocolo. Durante un período de siete años (2016–2022), la implementación del protocolo preservó 23 nidos (es decir, el 15.2% del total de 151 nidos). De estos nidos protegidos, 37 crías emplumaron, lo que representó el 16% de todas las crías emplumadas en la región en este período. En relación con el costo financiero de proteger la naturaleza en Gipuzkoa, la implementación de este protocolo fue económica, totalizando <0.1% del presupuesto del departamento para la gestión de hábitats naturales en la provincia. [Traducción del equipo editorial] [ABSTRACT FROM AUTHOR]

This study aimed to improve the sustainability of the kraft pulp production process by recovering Pinus radiata and Eucalyptus grandis wastewater generated during the bleaching process. The effluents were obtained from the first alkaline extraction stage (E0) of the ECF bleaching sequence used to produce white Kraft cellulose, considering that this stage is where the highest contamination by phenolic compounds occurs and the effluent exhibits an intense color. A photochemical oxidation system, utilizing TiO2/S2O8 2-/UV, was implemented to generate in situ two highly oxidizing radical species, with high redox potential, a hydroxyl radical (HO• 2.8 eV ) and a sulfate radical (SO4 •- 2.5-3.1 eV), which promote rapid degradation of contaminants. To obtain the optimal response, we employed the 2n model to construct a matrix of 15 experiments, utilizing the Box-Behnken design. According to the experimental variables studied, phenolic compounds were completely removed from the Eucalyptus effluent (0.0312 min-1) and 80% of them were removed from the pine effluent (0.0102 min-1), at pH 5.0 with 0.6 gL-1 of persulfate and 1.0 gL-1 of titanium dioxide. Under these conditions, the bioavailability of effluents from Pinus radiata and Eucalyptus grandis increases from 0.16 and 0.26 to 0.90, after the treatment. The excellent bioavailability of the effluents obtained after the treatment demonstrates that the process used is efficient in recovering wastewater from the pulp industry and that the treated water could be reused in the same process or returned to the ecosystem, without harming the environment. [ABSTRACT FROM AUTHOR]

The easy implementation of a nature-based solution (NBS) to address a prompt stabilisation of burnt areas may be crucial in the Mediterranean forest environment. A plot scale hydrological and ecological survey was conducted in a pine forest of the Aspromonte Massif (southern Italy) affected by a high fire severity in summer 2021. The hydrological response to 30 rainfall event groups is analysed by monitoring nine sloping plots distributed into three plot blocks (forested according to the pre-fire situation, burnt with randomly directed felled logs and burnt with manually felled logs redirected along contour lines). The hydrological response of bare soil is mitigated by about 30% through the combined effects of the NBS and the vegetation cover by pioneer species. Although the regeneration of Pinus radiata is scarcer in the arranged plots, the spontaneous vegetation, once gone, prepares better edaphic conditions for the triggering of forest dynamics assured by the auto-succession of Pinus radiata. In terms of woody mechanical resistance, NBS durability is compatible with the time required for seedlings to regenerate the forest ecosystem. The results achieved so far encourage further research on higher slopes and complementary aspects (vegetal and animal biodiversity, economic factors, etc.). [ABSTRACT FROM AUTHOR]

As wildfire becomes increasingly frequent, many serotinous plant populations risk local extirpation if fire recurs prior to sufficient seed accumulation in the canopy (i.e., "immaturity risk"). Following two 2018 wildfires in northwestern California, we studied seed viability, cone production, and postfire regeneration of a serotinous conifer, knobcone pine (Pinus attenuata), with stand ages (time since fire) ranging from 6 to 79 years. Cone density per tree was more strongly associated with tree diameter than age, and cone density was positively related to postfire seedling regeneration. Most of the postfire knobcone pine regeneration established during the first year with high survivorship in the following first postfire year. Adjusting for survivorship, the estimated minimum age for knobcone pine to promote self‐replacement (one recruit per tree) was 9.5 years (or 4.6‐cm dbh) and the probability of reburning at the modern fire rotation of 43 years was 19.8%. Based on our results, we found that immaturity risk was currently low for knobcone pine. Our approach provides a quantitative method to assess immaturity risk in knobcone pine and other serotinous conifer species that can be used to evaluate future risk under rapidly changing climate and fire conditions. [ABSTRACT FROM AUTHOR]

The objective of this study was to assess the potential gains in log processing yield when integrating sawmill and engineered wood products manufacturing, a process which enables the use of random board widths and higher wane allowances than normal. The simulation was utilized and validated against real log sawing. The validation study showed that simulations consistently over-estimated the actual volume recovery by 2.1%. Simulation results showed that logs with smaller diameters returned higher recovery increases when adopting an increased wane strategy compared to large-diameter logs. When combining both increased wane and random width strategies, the recoveries were the highest. Using a weighted average of log classes (according to a common log size distribution in South African sawmills) an increased wane strategy returned higher recovery (11.0%) than a random width strategy (2.0%), but a combined strategy (13.0%) was the most efficient. The gains in volume recovery presented in this study showed that it is worthwhile to consider the integration of engineered products manufacturing in primary log processing using random widths strategy combined with higher wane allowance. For better use of the raw material, the maximum wane that engineered products can allow without compromising its strength and stiffness must be further investigated. [ABSTRACT FROM AUTHOR]

In this work, the relationship between relative crystallinity with mechanical and vibroacoustic properties of Pinus radiata wood, before and after heat treatment, was studied. Heat treatment was applied using a laboratory oven with a tray of liquid nitrogen inside to generate an oxygen-depleted atmosphere. To determine the vibrational properties, a free beam measurement system was used, and by means of an FTIR infrared imaging system, the relative crystallinity in the wood was determined. There were differences in properties between untreated and treated wood depending on the treatment conditions. In treated samples, the higher temperature and time produce an increase in the coefficient of sound radiation, a decrease in specific acoustic impedance and a non-significant change in the speed of sound. Moreover, the best degree of association between crystallinity and mechanical and vibrational properties was achieved at higher temperature and time, coinciding in turn with the conditions that allow an improvement in the vibrational properties of Pinus radiata wood. In general, the relationships described in this work contribute to the consideration that fast-growing species can have a more noble use through heat treatments. [ABSTRACT FROM AUTHOR]

Eucalyptus globoidea is an emerging plantation species. Its naturally durable heartwood has the potential to be used for solid wood outdoor products. Good machinability of a timber is essential for solid wood processing but was unknown for E. globoidea. The ASTM D1666 standard was used to assess the machinability of E. globoidea and compared to that of Pinus radiata, the dominating resource for the local wood processing industry and well-known for its good machinability. This study showed that E. globoidea machined equally well or better than P. radiata in planing, boring, mortising, grooving, edging, and turning. Sanding E. globoidea (723 kg/m3) was not possible at the prescribed settings, whereas a smooth finish was obtained for the lower density P. radiata (461 kg/m3). Reducing the sanding depth resulted in a satisfactory sanding finish. Defects that determined the machine scores were identified. When boring, mortising and grooving E. globoidea timber, most defects were chipping caused by the tool exiting the piece. When edging, most care needs to be taken at the corner. The comparable machinability of E. globoidea and P. radiata according to ASTM D1666 indicated that the well-established P. radiata wood processing industry should be able to process E. globoidea. [ABSTRACT FROM AUTHOR]

Microbiomes play critical roles in host functioning and, therefore, there is increasing interest in the microbiome assembly of plants. However, sampling strategies for long-lived perennial trees need to be standardized to produce robust data that accurately represent the microbiome over time. This issue is currently unresolved because there is little evidence indicating which portion of perennial tree species (e.g., root region or surrounding soil) is the best to sample to produce the most accurate measure of microbiome communities. Our aim was to sample different compartments of a plant's belowground microbiome to identify the optimal sampling strategy to account for the microbial community present. We found that the structure of the microbial community depends most strongly on the environment (site) and compartment of sample collected (bulk soil, rhizosphere, or rhizoplane), rather than the depth or cardinal direction of the sample. We also found that the microbial community increased in diversity with increased distance from the tree within the rhizoplane and rhizosphere. The data presented here provide systematic evidence for a pragmatic and robust sampling regime that was tested and validated across different environments and soil types while controlling for host genotype. This sampling regime will enable effective partitioning of root compartments when studying the microbiome associated with perennial tree species, allowing targeted questions about the microbiome to be explored with greater accuracy.

This study demonstrates a framework for using high-resolution satellite imagery to automatically map and monitor outbreaks of red needle cast (Phytophthora pluvialis) in planted pine forests. This methodology was tested on five WorldView satellite scenes collected over two sites in the Gisborne Region of New Zealand's North Island. All scenes were acquired in September: four scenes were acquired yearly (2018–2020 and 2022) for Wharerata, while one more was obtained in 2019 for Tauwhareparae. Training areas were selected for each scene using manual delineation combined with pixel-level thresholding rules based on band reflectance values and vegetation indices (selected empirically) to produce 'pure' training pixels for the different classes. A leave-one-scene-out, pixel-based random forest classification approach was then used to classify all images into (i) healthy pine forest, (ii) unhealthy pine forest or (iii) background. The overall accuracy of the models on the internal validation dataset ranged between 92.1% and 93.6%. Overall accuracies calculated for the left-out scenes ranged between 76.3% and 91.1% (mean overall accuracy of 83.8%), while user's and producer's accuracies across the three classes were 60.2–99.0% (71.4–91.8% for unhealthy pine forest) and 54.4–100% (71.9–97.2% for unhealthy pine forest), respectively. This work demonstrates the possibility of using a random forest classifier trained on a set of satellite scenes for the classification of healthy and unhealthy pine forest in new and completely independent scenes. This paves the way for a scalable and largely autonomous forest health monitoring system based on annual acquisitions of high-resolution satellite imagery at the time of peak disease expression, while greatly reducing the need for manual interpretation and delineation. [ABSTRACT FROM AUTHOR]

Featured Application: This study aimed to synthesize a novel biomass-based, chemically activated carbon from Pinus radiata sawdust and to investigate its effectiveness in the removal of wood dyes from aqueous solutions in a fixed-bed column. In this paper, an activated carbon obtained from Pinus radiata sawdust is applied to remove blue, red, and black wood dyes from aqueous solutions in a fixed-bed column. The flow rate (7.7–30.8 mL min−1), initial dye concentration (25–500 mg L−1), and bed height (2–4 cm) highly influence the breakthrough-curves' features. The results indicate that the adsorption capacity increased by decreasing the flow rate and increasing the initial dye concentration, except for the black dye, and increasing bed height, except for the red dye. In addition, the breakthrough time changed by modifying the studied variables. The curves became steeper as the flow rate increased and as the bed height decreased. Also, by increasing the inlet dye concentration, the breakthrough time decreased significantly, and sharper breakthrough curves were obtained. The activated carbon with a surface area of 2826 m2 g−1 led to high values of the adsorption capacity between 150 and 1300 mg g−1. The Yoon–Nelson and Thomas models were the ones that best described the adsorption data. The activated carbon saturated with black dye could be used in three successive cycles after regeneration with H2O2. [ABSTRACT FROM AUTHOR]

Monosaccharides such as L-arabinose (Ara) and D-tagatose (derived from D-galactose, Gal) are low-calorie sweeteners associated with improved glycaemic and insulin control compared to disaccharides such as sucrose. However, alternative sources and better sugar-sugar separation methods are needed to improve the sustainability and economics of their production. Here, these sugars were obtained from purified and ultrafiltered compression screw pressate (CSP) of thermo-mechanical pulping of softwood (Pinus radiata) and orange peels (OPs). Basubstituted zeolite X (BaX) molecular sieves showed superior separation performance of Ara from other sugars compared to conventional Ca-form ion exchange resin. To facilitate subsequent separation of sugars, OP hydrolysates were fermented to leave just Ara and Gal, while OP pectin was hydrolysed to generate a Gal-rich mixture. Overall, BaX has good potential for separating Ara from Ara-rich hydrolysates containing several different sugars. It is also suited for separating Ara and another monosaccharide such as Gal or Xyl in the absence of other sugars. [ABSTRACT FROM AUTHOR]

This study assessed the efficacy of mild-alkaline extraction from P. radiata bark in obtaining proanthocyanidin (PA)-rich extracts. When the bark was treated with three types of bases--Na2CO3, NaHCO3, and NaOH--at varying concentrations, the extract yields increased with higher concentrations. When the pH of the extracts exceeded 7, the PA content and antioxidant activity were remarkably reduced. This result suggests that the pH holds a greater effect in the alkaline extraction of the bark rather than the type of base used. Among the bases used, NaHCO3 was selected and the extraction conditions of pine bark were examined at a concentration where the pH of the extract did not exceed 7. The extraction time during mild-alkaline extraction using 0.2% NaHCO3 was reduced compared to water-only extraction at the same temperature. Moreover, the extract yields were over 10% higher than those of water extraction, and the dried extracts exhibited good solubility in water. The mild-alkaline extracts were characterized using FT-IR and 13C NMR spectroscopic techniques, and acidic alcoholysis. Analyses of the spectra of the mildalkaline extracts showed similarities to that of pure PA and hot water extract. This result indicated that PA in the bark was not significantly affected during mild-alkaline extraction. [ABSTRACT FROM AUTHOR]

Plantations, and associated invasions, of exotic Pinus trees occur extensively in the southern hemisphere, threatening the persistence of biodiverse Mediterranean‐climate vegetation. Large‐scale decommissioning of such plantations in the eastern Cape Floristic Region (South Africa) enabled a wide‐ranging study showing successful passive restoration of fynbos vegetation after afforestation. Using a paired study design, we compared the diversity, and floristic and growth‐form composition of post‐fire recovering fynbos in former plantations with that in recently burnt neighboring fynbos in a natural state within the Garden Route National Park. The fynbos of the study area showed good autogenic recovery after several decades of pine afforestation and a fire subsequent to the clearcutting of these trees. On average, native plant abundance and species richness (particularly of shrubs) were significantly lower, and non‐native plant species richness significantly higher, in former plantation areas than in natural fynbos, but these differences were small. Species diversity (Shannon–Wiener index) did not differ significantly between the two vegetation states. The former plantations harbored 91% of the number of native species that the natural fynbos had, while the similarity of the two floras was 65%. Non‐metric multidimensional scaling ordination and multivariate generalized linear models accordingly showed no clear distinction in community composition between the two vegetation states. We concluded that the restoration potential of the montane grassy fynbos in the study area is superior to that previously documented in montane proteoid fynbos, and that fire and invasive alien plant control after clearcutting of the plantations is essential to promote fynbos restoration. [ABSTRACT FROM AUTHOR]

Despite the utility of thermal imagery for characterising the impacts of water stress on plant physiology, few studies have been undertaken on plantation-grown conifers, including the most widely planted exotic species, radiata pine. Using data collected from a pot trial, where water was withheld from radiata pine over a nine-day period, the objectives of this study were to (i) determine how rapidly key physiological traits change in response to water stress and (ii) assess the utility of normalised canopy temperature, defined as canopy temperature–air temperature (Tc–Ta), for detecting these physiological changes. Volumetric water content remained high in the well-watered control treatment over the course of the experiment (0.47–0.48 m3 m−3) but declined rapidly in the water stress treatment from 0.47 m3 m−3 at 0 days after treatment (DAT) to 0.04 m3 m−3 at 9 DAT. There were no significant treatment differences in measurements taken at 0 DAT for Tc–Ta, stomatal conductance (gs), transpiration rate (E) or assimilation rate (A). However, by 1 DAT, differences between treatments in tree physiological traits were highly significant, and these differences continued diverging with values in the control treatment exceeding those of trees in the water stress treatment at 9 DAT by 42, 43 and 61%, respectively, for gs, E and A. The relationships between Tc–Ta and the three physiological traits were not significant at 0 DAT, but all three relationships were highly significant from as early as 1 DAT onwards. The strength of the relationships between Tc–Ta and the three physiological traits increased markedly over the duration of the water stress treatment, reaching a maximum coefficient of determination (R2) at 7 DAT when values were, respectively, 0.87, 0.86 and 0.67 for gs, E and A. The early detection of changes in tree physiology from 1 DAT onwards suggests that thermal imagery may be useful for a range of applications in field-grown radiata pine. [ABSTRACT FROM AUTHOR]

Upland soils are the only known biological sink for methane (CH4) by methanotrophic bacteria consumption. This process is mainly limited by the diffusion processes related to the soil's physical characteristics, which can be modified because of changes in land use depending on the soil type, the original system and the new land use converted. Our study focused on determining the differences in soil CH4 uptake because of changes in land use (from natural grassland to agricultural land and two Pinus radiata afforestation, differing in thinning management) and on determining which are the main drivers that control CH4 uptake in the studied soil type (Hapludoll), with focus on the diffusion process. CH4 fluxes were measured 12 times with the static chamber technique between October 2015 and April 2019. Also, CH4 gradient concentration in the soil profile and physical and chemical variables were measured on the same dates. All land uses studied acted as net CH4 sinks. Land-use change from grassland to agriculture decreased soil CH4 uptake (~37% ± 19), whereas afforestation increased (~85% ± 73) this environmental service related to natural grassland. We found that the main drivers that control CH4 uptake in this soil are water and air-filled pore space, variables that govern soil CH4 diffusion; they are mostly related to differences in bulk density (compaction) among land uses. Organic matter was also an important driver, mainly related to soil structure. Land-use change affected all of these drivers. CH4 concentration presented differences at deeper soil layers only in the two afforestations, which differed in management (pruning and thinning vs. no management). However, CH4 uptake did not present significant differences between them, suggesting that there is no need for a high tree cover to increase the CH4 sink of the soil. This mixed tree and herbaceous cover may result in a similar environmental service output, increasing the options of land uses. [ABSTRACT FROM AUTHOR]

In Ethiopia, Pinus radiata and Pinus patula are extensively cultivated. Both plantations frequently serve as habitats for edible fungi, providing economic and ecological importance. Our study aims were: (i) to investigate how plantation age and tree species influence the variety of edible fungi and sporocarps production; (ii) to determine edaphic factors contributing to variations in sporocarps composition; and (iii) to establish a relationship between the most influencing edaphic factors and the production of valuable edible mushrooms for both plantation types. Sporocarps were collected weekly from permanent plots (100 m2) established in 5-, 14-, and 28-year-old stands of both species in 2020. From each plot, composite soil samples were also collected to determine explanatory edaphic variables for sporocarps production and composition. A total of 24 edible species, comprising 21 saprophytic and three ectomycorrhizal ones were identified. Agaricus campestroides, Morchella sp., Suillus luteus, Lepista sordida, and Tylopilus niger were found in both plantations. Sporocarp yields showed significant variation, with the highest mean production in 28-year-old stands of both Pinus stands. Differences in sporocarps variety were also observed between the two plantations, influenced by factors such as pH, nitrogen, phosphorus, potassium, and cation exchange capacity. Bovista dermoxantha, Coprinellus domesticus, and A. campestroides made contributions to the variety. The linear regression models indicated that the abundance of specific fungi was significantly predicted by organic matter. This insight into the nutrient requirements of various fungal species can inform for a better plantation management to produce both wood and non-wood forest products. Additionally, higher sporocarps production in older stands suggests that retaining patches of mature trees after the final cut can enhance fungal habitat, promoting diversity and yield. Thus, implementing this approach could provide supplementary income opportunities from mushroom sales and enhance the economic outputs of plantations, while mature trees could serve as a source of fungal inoculum for new plantations. [ABSTRACT FROM AUTHOR]