Search

This study aimed to compare and assess the genetic diversity and trends among the introduced family provenance, first-cycle superior trees breeding provenance, and improved-generation superior trees breeding provenance of Pinus elliottii using EST-SSR markers. The goal was to provide a foundation for advanced genetic improvement and sustainable utilization of P. elliottii in Jiangxi Province. A total of 417 individuals were analyzed for their genetic diversity and population structure using 19 pairs of SSR markers. The analysis identified 103 alleles across all the samples, with an average of 5.421 alleles per locus. Compared to other coniferous species, P. elliottii exhibited a moderate to high level of genetic diversity (I = 0.862, He = 0.457). Analysis of the molecular variance (AMOVA) revealed that 97.90% of the genetic variation occurred within provenances, consistent with a low genetic differentiation coefficient (Fst = 0.016 < 0.05) and high gene flow (Nm = 15.715) among provenances. In addition, analysis using STRUCTURE v. 2.3.4 software divided the 417 germplasm samples into two distinct groups, corroborating the results of the principal coordinates analysis (PCoA) and the unweighted pair group method with arithmetic (UPGMA) clustering analysis. Overall, the germplasm resources of P. elliottii exhibited rich genetic diversity, with the majority of the genetic variation occurring within provenances. For the genetic improvement of high-resin-yielding slash pines, breeding programs should prioritize populations with high genetic diversity while carefully selecting superior individuals from within those populations. These findings provide a solid foundation for breeding high-resin-yielding varieties and for future research on the sustainable utilization of these valuable resources. [ABSTRACT FROM AUTHOR]

The natural forest ecosystems of South Florida, USA, support a high biodiversity of plant and animal species and provide valuable ecosystem services. However, these ecosystems remain poorly represented in global studies, primarily due to a paucity of standardized data. Here, we present previously unpublished data from 332 censuses of 54 permanent 1‐ha tree inventory plots in the Racoon Point area of Big Cypress National Preserve, Florida, USA, including a total of nearly 100,000 measurements (diameter or height) of > 17,000 individual living trees and palms (with additional measurements of nearly 6000 dead pine snags) collected sporadically over a 19‐year period (1993–2012). These data, which were originally collected as part of a project to investigate tree responses to different experimental burning regimes, provide unique insight into the diversity, composition, structure, and dynamics of South Florida's unique and endangered pine forest ecosystems. Data files include the species identity, size (dbh = diameter at breast height), and location of all trees ≥ 5 cm dbh in 54 individual tree plots. Additional data are provided about heights of palm trees, and the location and burn history of each plot. These data are freely available for noncommercial scientific use under a Creative Commons license; users are encouraged to cite this paper when using the data. [ABSTRACT FROM AUTHOR]

This study aimed to produce polymer-wood composites via in situ polymerization. For this purpose, the polymer-wood composites were manufactured using vacuum in a horizontal autoclave. Physical, mechanical, and durability characteristics were evaluated. The treatments provided significant increases of over 30% and 60% in flexural strength and modulus, respectively. All treatments resulted in lower water absorption and greater dimensional stability of the wood. Furthermore, the treatments altered the surface of the impregnated wood, showing increased surface hydrophobicity, roughness, weather resistance, and modified coloration. Treated woods also exhibited an improvement of over ∼40% in resistance to termite attack. [ABSTRACT FROM AUTHOR]

Plantation forests were introduced into South Africa to satisfy the regional demand for wood-based products, which are largely found in the Mpumalanga province. To better understand the impacts of climate on the dominant height growth of commercially important plantation species, enumeration data collected from 2012 to 2023 was scrutinised, representing 34740 plots in 2082 plantation compartments. Statistically significant multiple linear regression models were developed to predict dominant heights for Pinus elliottii, Pinus taeda, Pinus patula, and Pinus patulax Pinus tecunumanii hybrids using climate variables as independent factors. Mean annual maximum temperature was statistically significant when modelling dominant height for P. elliottii, while winter maximum temperature was significant for P. taeda, P. patula, and P. patula x P. tecunumanii. Rainfall was found to be significant for P. elliottii and P. taeda, while spring rainfall was found to be more important when modelling dominant height for P. patula. Interestingly, autumn rainfall was found to have a negative impact on dominant height growth of P. taeda and P. patula, while rainfall was not significant in P. patula x P. tecunumanii. The findings imply that the southern pines have water thresholds, while Mexican pines are more temperature limited than water limited. [ABSTRACT FROM AUTHOR]

Abstract The increasing water contamination by toxic heavy metals, particularly hexavalent chromium, has become a significant environmental concern. This study explores the pyrolysis of termite-processed biomass, specifically Pinus elliottii particleboard and its termite droppings (TDs), to produce biochar and its application for chromium (VI) adsorption. Termite droppings, rich in lignin, and particleboard, rich in cellulose, were pyrolyzed at various temperatures to assess the effect of biomass composition on biochar properties. The study found that lignin-rich termite droppings produced biochar with higher fixed carbon content and specific surface area than cellulose-rich particleboard biochar. FTIR and Raman spectroscopy revealed significant molecular structure changes during pyrolysis, which influenced the adsorption capabilities of the biochar. Adsorption experiments demonstrated that TD biochar exhibited significantly higher chromium (VI) adsorption capacity, attributed to its distinct chemical composition and enhanced surface properties due to higher lignin content. These findings underscore the crucial role of lignin in producing efficient biochar for heavy metal adsorption, highlighting the practical applicability of termite-processed biomass in water purification technologies.

Slash pine (Pinus elliottii Engelm.), an important economic tree species with a high resin yield, is extensively cultivated in southern China. Somatic embryogenesis (SE) technology could hasten the breeding of P. elliottii through improving seedling quality and number, but mass production of somatic embryos remains constrained by various factors. We described an efficient SE system through indirect route and investigate the effects of genotype, phytohormones and culture condition on SE. Immature zygotic embryos of three open-pollinated mother trees collected during 2020–2023 were utilized for initiation of pro-embryogenic masses (PEMs). The initiation of PEMs was significantly influenced by seed sources (families) (p < 0.05). The addition of 2,4-dichlorophenoxyacetic acid (6 mg/L), 6-benzylaminopurine (1 mg/L) and kinetin (2 mg/L) effectively improved initiation rates by up to 15.67 ± 1.89%. Furthermore, glutamine addition to the maturation medium enhanced the yield of somatic embryos during culture. The optimum concentration range of activated carbon within the germination medium spanned from 3–4.5 g/L. Inoculation with ectomycorrhizal fungus Laccaria amethystea enhanced the root length of regenerated plantlets, reaching 7.92 ± 4.06 cm. The regenerated plantlets inoculated with Pisolithus orientalis and Xerocomus chrysenteron showed improved survival during the acclimatization phase, with 100% survival of mycorrhizae-treated plantlets after 3 months of acclimatization in the greenhouse. We clarified the SE conditions suitable for P. elliottii, and the SE system and mycorrhizal method we used can be applied to mass production of plantlets.Key Message: • Efficient somatic embryogenesis technology for Pinus elliottii was established; • Regenerated plants inoculated with mycorrhizal fungi Pisolithus orientalis and Xerocomus chrysenteron had 100% survival after transplanting. [ABSTRACT FROM AUTHOR]

Canopy Chlorophyll Content (CCC) is an important physiological indicator that reflects the growth stage of trees. Accurate estimation of CCC facilitates dynamic monitoring and efficient forest management. In this study, we used high-resolution remote sensing images obtained by uncrewed aerial vehicles (UAVs) equipped with multispectral sensors (red, green, blue, near-infrared, and red-edge) to estimate CCC of lodgepole pine (Pinus elliottii). Our aim was to determine the optimal machine learning model between support vector regression (SVR) and random forest regression (RFR) for predicting CCC and to evaluate the effectiveness of multispectral bands along with 21 vegetation indices (VIs) in the estimation process. Individual tree boundaries were derived from the canopy height model (CHM) based on three-dimensional (3D) point clouds generated using structure from motion. These images, combined with continuous field measurements from January to December, provided comprehensive data for our analysis. The results showed that the SVR method outperformed the RFR method in estimating leaf chlorophyll content (LCC), with fitting R2 values up to 0.692 and RMSE values up to 0.168 mg⋅g−1. Overall, the study highlights the potential of UAV-based remote sensing for multitemporal forest monitoring, offering advances in precision forestry and tree breeding. [ABSTRACT FROM AUTHOR]

In order to select superior clones with strong resin-producing capacity and high resin-quality from the existing fast-growing timber clones in seed orchard of Pinus elliottii, and to make high use of crop germplasm resource, 36 clones in the first generation of slash pine seed orchard were used as materials to determine their resin yield, resin mass flow rate and DBH growth, and to analyze their resin composition by GC-MS. Based on the above indicators, correlation analysis and cluster analysis was used to comprehensively evaluate the production and quality of resin among 36 clones. The results were as follows: (1) There were a total of 21 pine resin components, including 8 monoterpenes and 13 diterpenes. (2) Correlation analysis showed that the resin mass flow rate (RMR) had significant and positive correlation with the total content of monoterpene, weakly negatively correlates to abietic-type resin acid, and not significantly correlated to pimaric-type resin acid. (3) Based on the cluster analysis results integrating four types of indicators as the total monoterpene content, resin mass flow rate, abietic-type resin acid and pimaric-type resin acid, 36 clones could be divided into three categories and the difference between each type was significant. The performance of Class 1 was much better than that of the other two categories. (4) There were 17 high-resin yield pine clones (ERM≥15.15) among 36 clones, and on the basis of this, four clones (6-44, 4-11-1, 1-38, 3-64) display higher monoterpenes content, while four clones (4-11-1, 3-64, 2-0420, 3-468) showed higher contents of pimaric-type resin acid. And the content of abietic-type resin acid of clone 2-173 was the highest. In summary, a total of 21 pine resin components of P. elliottii were identified, and 36 clones were evaluated based on four indicators: the total monoterpene content, resin mass flow rate, abietic-type resin acid and pimaric-type resin acid. We not only analyzed qualitatively the resin composition but also evaluated quantitatively the resin-producing capacity of 36 clones in slash pine seed orchard. Our findings provide the scientific references for the targeted breeding of pine resin components and lay a foundation for subsequent heredity breeding and gene improvement of P. elliottii.

This study aimed to compare and assess the genetic diversity and trends among the introduced family provenance, first-cycle superior trees breeding provenance, and improved-generation superior trees breeding provenance of Pinus elliottii using EST-SSR markers. The goal was to provide a foundation for advanced genetic improvement and sustainable utilization of P. elliottii in Jiangxi Province. A total of 417 individuals were analyzed for their genetic diversity and population structure using 19 pairs of SSR markers. The analysis identified 103 alleles across all the samples, with an average of 5.421 alleles per locus. Compared to other coniferous species, P. elliottii exhibited a moderate to high level of genetic diversity (I = 0.862, He = 0.457). Analysis of the molecular variance (AMOVA) revealed that 97.90% of the genetic variation occurred within provenances, consistent with a low genetic differentiation coefficient (Fst = 0.016 < 0.05) and high gene flow (Nm = 15.715) among provenances. In addition, analysis using STRUCTURE v. 2.3.4 software divided the 417 germplasm samples into two distinct groups, corroborating the results of the principal coordinates analysis (PCoA) and the unweighted pair group method with arithmetic (UPGMA) clustering analysis. Overall, the germplasm resources of P. elliottii exhibited rich genetic diversity, with the majority of the genetic variation occurring within provenances. For the genetic improvement of high-resin-yielding slash pines, breeding programs should prioritize populations with high genetic diversity while carefully selecting superior individuals from within those populations. These findings provide a solid foundation for breeding high-resin-yielding varieties and for future research on the sustainable utilization of these valuable resources.

In order to select superior clones with strong resin-producing capacity and high resin-quality from the existing fast-growing timber clones in seed orchard of Pinus elliottii, and to make high use of crop germplasm resource, 36 clones in the first generation of slash pine seed orchard were used as materials to determine their resin yield, resin mass flow rate and DBH growth, and to analyze their resin composition by GC-MS. Based on the above indicators, correlation analysis and cluster analysis was used to comprehensively evaluate the production and quality of resin among 36 clones. The results were as follows: (1) There were a total of 21 pine resin components, including 8 monoterpenes and 13 diterpenes. (2) Correlation analysis showed that the resin mass flow rate (RMR) had significant and positive correlation with the total content of monoterpene, weakly negatively correlates to abietic-type resin acid, and not significantly correlated to pimaric-type resin acid. (3) Based on the cluster analysis results integrating four types of indicators as the total monoterpene content, resin mass flow rate, abietic-type resin acid and pimaric-type resin acid, 36 clones could be divided into three categories and the difference between each type was significant. The performance of Class 1 was much better than that of the other two categories. (4) There were 17 high-resin yield pine clones (ERM≥15.15) among 36 clones, and on the basis of this, four clones (6-44, 4-11-1, 1-38, 3-64) display higher monoterpenes content, while four clones (4-11-1, 3-64, 2-0420, 3-468) showed higher contents of pimaric-type resin acid. And the content of abietic-type resin acid of clone 2-173 was the highest. In summary, a total of 21 pine resin components of P. elliottii were identified, and 36 clones were evaluated based on four indicators: the total monoterpene content, resin mass flow rate, abietic-type resin acid and pimaric-type resin acid. We not only analyzed qualitatively the resin composition but also evaluated quantitatively the resin-producing capacity of 36 clones in slash pine seed orchard. Our findings provide the scientific references for the targeted breeding of pine resin components and lay a foundation for subsequent heredity breeding and gene improvement of P. elliottii. [ABSTRACT FROM AUTHOR]

Copyright of Ciência Florestal (01039954) is the property of Ciencia Florestal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To reduce dependence on wood and deforestation, alternative materials have been considered. This research evaluated particleboards panels of Pinus elliotti mixed with residues of polyethylene terephthalate (PET) in flakes with 50% of each material, glued with 10% of castor oil-based polyurethane resin (PUR). The temperature during board production was varied to evaluate its influence on the physical and mechanical properties of the boards. The study concludes that the increase in temperature did not result in a significant improvement in the particleboard properties, but their results showed application potential according to the normative standards.

RESUMO A melhor utilização da madeira depende de suas propriedades químicas, físicas e anatômicas. Diversos fatores bióticos e abióticos podem interferir em maior ou menor magnitude nas propriedades da mesma e conseqüentemente, em sua qualidade. Esta pesquisa teve como objetivo o estudo da variação da densidade da madeira, visando obter subsídios face sua melhor aplicação. O material empregado, constituiu-se de amostras de madeira de 12 árvores de Pinus elliottii com diferentes idades de crescimento. Os Resultados obtidos mostraram haver variação da densidade nos sentidos longitudinal e radial e em função da idade de crescimento. A densidade aumentou da medula para a casca e com a idade de crescimento e diminuiu da base para o topo. Baseado nesta variação, foi possível distinguir regiões onde os valores de densidades são praticamente idênticos e regiões onde eles diferem entre si, permitindo assim, classificar a madeira em termos de densidade e sugerir seu melhor emprego.

A solid understanding of the efficiency of early selection for fiber dimensions is a prerequisite for breeding slash pine (Pinus elliottii Engelm.) with improved properties for pulp and paper products. Genetic correlations between size of fibers, wood quality and growth properties are also important. To accomplish effective early selection for size of fibers and evaluate the impact for wood quality traits and ring widths, core samples were collected from 360 trees of 20 open-pollinated Pinus elliottii families from three genetic trials. Cores were measured by SilviScan, and the age trends for phenotypic values, heritability, early-late genetic correlations, and early selection efficiency for fiber dimensions, such as tangential and radial fiber widths, fiber wall thickness and fiber coarseness, and their correlations with microfibril angle (MFA), modulus of elasticity (MOE), wood density and ring width were investigated. Different phenotypic trends were found for tangential and radial fiber widths while fiber coarseness and wall thickness curves were similar. Age trends of heritability based on area-weighted fiber dimensions were different. Low to moderate heritability from pith to bark (~ 0.5) was found for all fiber dimension across the three sites except for tangential fiber width and wall thickness at the Ganzhou site. Early-late genetic correlations were 0.9 after age of 9 years, and early selection for fiber dimensions could be effective due to strong genetic correlations. Our results showed moderate to strong positive genetic correlations for modulus of elasticity and density with fiber dimensions. The effects on fiber dimensions were weak or moderate when ring width or wood quality traits were selected alone. Estimates of efficiency for early selection indicated that the optimal age for radial fiber width and fiber coarseness was 6–7 years, while for tangential fiber width and wall thickness was 9–10 years. [ABSTRACT FROM AUTHOR]

To reduce dependence on wood and deforestation, alternative materials have been considered. This research evaluated particleboards panels of Pinus elliotti mixed with residues of polyethylene terephthalate (PET) in flakes with 50% of each material, glued with 10% of castor oil-based polyurethane resin (PUR). The temperature during board production was varied to evaluate its influence on the physical and mechanical properties of the boards. The study concludes that the increase in temperature did not result in a significant improvement in the particleboard properties, but their results showed application potential according to the normative standards. [ABSTRACT FROM AUTHOR]

Tricholoma matsutake is one of the edible ectomycorrhizal fungi with great economic and ecological values. Artificially mycorrhized seedlings inoculated with T. matsutake strains from Finland and Japan have been widely reported. However, few reports on the morphological characteristics of mycorrhizae synthesized from the Chinese T. matsutake strain are available to date. Here, we find that the T. matsutake strain YN1 from Yunnan province, China, can form well-developed ectomycorrhizae in symbiosis with both exotic (Pinus elliottii) and Chinese native (Pinus armandii) species. The symbiotic structures of ectomycorrhizae included obvious mantle sheaths and Hartig nets visible under a microscope. The ectomycorrhizae appeared earlier in a larger quantity in P. elliottii than in P. armandii in the culture-plate symbiotic system. The ectomycorrhizae obviously promoted the growth of potted P. armandii and P. elliottii, accompanied by the formation of shiro-like structures. Our results provide references for the effective management of ectomycorrhizae synthesis in both P. armandii and P. elliottii seedlings to form shiro-like structures, and also provide a new perspective for the afforestation and mushroom cultivation research on T. matsutake. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Northwest A & F University - Natural Science Edition is the property of Editorial Department of Journal of Northwest A&F University (Natural Science Edition) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Heat treatment of Pinus elliottii wood is an essential practice for improving its properties and durability. This study aims to evaluate the changes resulting from this process at three temperature ranges, for a period of 2 h. The main objective of this study was to evaluate the thermal modification process of P. elliottii wood at different temperatures over a two-hour period in a forced circulation laboratory oven. The study used samples of P. elliottii wood, subjected to heat treatments at three temperatures (160°C, 200°C and 240°C) for 2 h. Apparent density, chemical composition, thermal stability, mechanical and colorimetric properties were analysed to assess the effects of the treatments. The heat treatments on P. elliottii wood had varied results. The 160°C treatment increased rigidity and resistance, while the 200°C treatment provided greater thermal stability. Both are recommended for different purposes. However, the 240°C treatment damaged the wood's properties. There was a decrease in mass loss with no significant impact on specific mass. The wood also darkened as a result of the heat treatments. [ABSTRACT FROM AUTHOR]

Oriented Strand Board is a structural wood composite with applications that require good physical and mechanical performance. The addition of ZnO nanoparticles is an alternative that has been studied in order to improve the properties of Oriented Strand Board panels. However, there is no information about its effect Oriented Strand Board. The aim of this work was to evaluate the influence of the addition of zinc oxide nanoparticles in two different percentages (0,25 % and 0,50 %) on the physical-mechanical properties of Oriented Strand Board panels produced with phenol-formaldehyde resin and on the heat transfer during hot-pressing. Oriented Strand Board panels were produced and tested according to European Standards. The addition of ZnO nanoparticles improved the dimensional stability of the panel, reducing its thickness swelling, and also increased the screw withdraw strength. The heat transfer during hot-pressing increased the temperature more quickly on boards with nanoparticles addition; on the other hand the final temperature of the control treatment was higher. [ABSTRACT FROM AUTHOR]

The longleaf pine (Pinus palustris Mill.) ecosystem is an endangered ecosystem in the southeastern USA, and efforts to restore the species are ongoing. However, in recent decades, the region has experienced drastic fluctuations between wet and dry growing season conditions from year to year, and it is not fully understood how these fluctuations have influenced the growth of P. palustris. To address this topic, we cored P. palustris trees in woodlands of southwest Georgia and used dendrochronology techniques to determine how climate fluctuations have influenced the growth and drought resilience of P. palustris. We also cored slash pine (Pinus elliottii Engelm.) trees in the same woodlands to compare growth between species. While P. palustris growth was less impacted by adverse climate conditions compared to P. elliottii, the strength of correlations between P. palustris growth and temperature, precipitation, and Palmer Drought Severity Index (PDSI) changed over time. In recent decades, climate conditions during the growing season became more influential on P. palustris growth than the previous year's conditions. This is concerning given that drought severity during the growing season has been increasing. Our results also indicate that P. palustris was less resilient to droughts during the 2000s and 2010s than to those of the 1950s. Under this new climate paradigm, our results suggest that P. palustris might be more susceptible to growth reductions and less resistant to droughts than once expected. This work highlights the importance of understanding the impact of novel climate conditions on P. palustris and has implications for restoration efforts, such as using silvicultural treatments that reduce tree vulnerability to drought (e.g., thinning) and promote other climate-adapted species in mixture with P. palustris. [ABSTRACT FROM AUTHOR]

Somatic embryogenesis is a crucial method for achieving clonal forestry in conifers. Understanding the development of zygotic embryos is essential not only for enhancing the efficiency and quality of somatic embryogenesis, but also for advancing forestry breeding programs. This study investigated dynamic changes of element and hormone contents during ZE development of Pinus elliottii and its hybrid P. elliottii × P. caribaea. Significant differences in embryo development speed among different clones were observed. Elemental analysis was conducted using inductively coupled plasma mass spectrometry (ICP-MS) and identified 68 elements, including major, minor, and beneficial elements. In both species, the contents of potassium (K), calcium (Ca), iron (Fe), boron (B) and five beneficial elements decreased during early ZE development, while phosphorus (P) and copper (Cu) increased. Significantly higher levels of K, Ca and Fe at the initial stage, and sulfur (S) and nickel (Ni) decreased at later stages were detected in P. elliottii than in the hybrid. For the other elements, except for very few significant differences at certain stages, most differences between the two species did not reach a significant level. The contents of endogenous hormones were determined and different accumulation patterns were detected in most hormones between the two species, except abscisic acid (ABA) which simultaneously decreased with developments by stage 8. Significant differences were found in indole-3-acetic acid (IAA) contents at most stages between species, while higher levels of total cytokinin (CK) at each stage were detected in the hybrid in comparison with those in P. elliottii. As a result, lower IAA to CK ratios in the hybrid than in P. elliottii. Methyl jasmonate (JA-me) and gibberellin A3 (GA3) contents showed a similar pattern and exhibited an M-shaped fluctuation in the hybrid. Furthermore, JA-me, GA3, gibberellin A4 (GA4) and brassinolide (BR) showed significantly higher levels in the hybrid than in P. elliottii. K-means clustering and correlation analyses were used to explore relationships between elements and hormones during embryo development, revealing complex interplay in both species. These data indicate different requirement in element and hormone contents for embryogenesis and suggest species-specific media composition for each step in somatic embryogenesis. The findings provide insights into their developmental processes and informing future research and applications in somatic embryogenesis and forestry breeding. [ABSTRACT FROM AUTHOR]

Changing forest structure with stand development is predicted to influence rainfall partitioning, and thus impact forest management and conservation strategies. Extensive pine silviculture in Florida also makes changes in rainfall partitioning with stand attributes consequential for regional water planning. We used weekly measurements of rainfall partitioning and soil water infiltration in two contrasting Pinus elliottii (slash pine) forest ecosystems in north Florida (USA), to quantify stand age and structural development impacts on forest hydrological function. Over 52 weeks - 45 with storms - we observed that stemflow and litterflow were significantly higher, and litter and total interception significantly lower, in the young stand (∼ 10 years since planting) than the mature stand (∼ 21 years since planting) (p <0.05). This was despite negligible differences in leaf area index and other crown structure parameters. We observed substantial differences in trunk storage capacity and trunk saturation point, with greater storage and thus reduced stemflow generation in the mature stand. We show that forest litter stores significant precipitation (7.3 % vs. 10.6 % of annual rainfall for young and mature pine stands, respectively) suggesting total interception predictions that neglect litter storage significantly underestimate actual rates, and overestimate root water availability. We further show that ignoring stemflow in small trees (i.e., young stands) underestimates total stemflow (3.4 % vs. 7.2 % of incident rainfall), leading to an overestimation of canopy and total interception in young stands. We used a reformulated Gash analytical model to obtain weekly estimates of canopy rainfall interception. Our most robust results were observed when we used in-situ partitioning parameters and dynamic canopy cover measurements. However, using literature-derived canopy ecohydrological parameters for southern pines also yielded acceptable predictions given dynamic canopy measurements, suggesting informative generality for application to new settings. Using static canopy measurements yielded consistently inferior results, suggesting that tracking canopy properties is more important for accurate interception predictions than local partitioning parameter estimation. Our results highlight the significance of forest maturity as a factor altering water storage capacity and rainfall partitioning in planted pine stands. • Stand age influences rainfall partitioning and soil infiltration in pine forests. • Stemflow is substantial in young pine stands, accounting for 7.2 % of rainfall. • Ignoring litter interception overestimates water availability in forest ecosystems. • Dynamic canopy measurements improve rainfall interception predictions. • Direct ecohydrological measurements are needed only if stand age varies significantly. [ABSTRACT FROM AUTHOR]

The longleaf pine (Pinus palustris Mill.) ecosystem is an endangered ecosystem in the southeastern USA, and efforts to restore the species are ongoing. However, in recent decades, the region has experienced drastic fluctuations between wet and dry growing season conditions from year to year, and it is not fully understood how these fluctuations have influenced the growth of P. palustris. To address this topic, we cored P. palustris trees in woodlands of southwest Georgia and used dendrochronology techniques to determine how climate fluctuations have influenced the growth and drought resilience of P. palustris. We also cored slash pine (Pinus elliottii Engelm.) trees in the same woodlands to compare growth between species. While P. palustris growth was less impacted by adverse climate conditions compared to P. elliottii, the strength of correlations between P. palustris growth and temperature, precipitation, and Palmer Drought Severity Index (PDSI) changed over time. In recent decades, climate conditions during the growing season became more influential on P. palustris growth than the previous year's conditions. This is concerning given that drought severity during the growing season has been increasing. Our results also indicate that P. palustris was less resilient to droughts during the 2000s and 2010s than to those of the 1950s. Under this new climate paradigm, our results suggest that P. palustris might be more susceptible to growth reductions and less resistant to droughts than once expected. This work highlights the importance of understanding the impact of novel climate conditions on P. palustris and has implications for restoration efforts, such as using silvicultural treatments that reduce tree vulnerability to drought (e.g., thinning) and promote other climate-adapted species in mixture with P. palustris.

Premise: Carnivorous plants are often associated with nutrient‐poor soils and fires. Fire can decrease available soil nitrogen (N) and increase light availability, thus potentially favoring carnivory if prey provide N. Prey can also be a source of phosphorus (P), however, and soil P‐availability often increases and competition for prey can decrease following fire. Carnivory thus might be more advantageous before fire when prey and/or soil P are more limiting. Methods: We examined nutrient limitation of growth in a carnivorous plant, Sarracenia alata, in a wet pine savanna in southeastern Mississippi, USA. We measured growth and N:P tissue concentration responses of adult plants to a factorial arrangement of prey capture, neighbor reduction, and addition of N, P, and ash to the soil. We tested two hypotheses: (1) Prey provide N, and neighbor reduction and ash addition increase light and soil P and thus the benefit of carnivory; and (2) Prey provide P, neighbor reduction increases prey and/or P, and prey exclusion reduces growth the most when neighbors are not reduced. Results: The exclusion of prey reduced growth more when neighbors were not reduced, an effect that was ameliorated slightly by the addition of P to the soil (the P‐limitation hypothesis). Prey exclusion caused a decrease in tissue P when N was added to the soil. Conclusions: The results of this study with adult plants differed from those of a previous study using small juvenile plants, suggesting a shift from light limitation to P and prey limitation with increasing size. [ABSTRACT FROM AUTHOR]

Oriented Strand Board is a structural wood composite with applications that require good physical and mechanical performance. The addition of ZnO nanoparticles is an alternative that has been studied in order to improve the properties of Oriented Strand Board panels. However, there is no information about its effect Oriented Strand Board. The aim of this work was to evaluate the influence of the addition of zinc oxide nanoparticles in two different percentages (0,25 % and 0,50 %) on the physical-mechanical properties of Oriented Strand Board panels produced with phenol-formaldehyde resin and on the heat transfer during hot-pressing. Oriented Strand Board panels were produced and tested according to European Standards. The addition of ZnO nanoparticles improved the dimensional stability of the panel, reducing its thickness swelling, and also increased the screw withdraw strength. The heat transfer during hot-pressing increased the temperature more quickly on boards with nanoparticles addition; on the other hand the final temperature of the control treatment was higher.

Slash pine (Pinus elliottii) is a crucial resin-tapping tree species in China, and its resin, an important product, is predominantly composed of monoterpenes and diterpenes. Although the influence of transcription factors (TFs) and microRNAs (miRNAs) on terpene biosynthesis is well known, the specific effect of miRNAs on terpene synthesis in slash pine remains insufficiently explored. This study employed comprehensive analyses, including transcriptome sequencing, small RNA sequencing, and degradation profiling, focusing on the bark and needles of slash pine at three distinct time points to unveil the miRNA-gene regulatory patterns governing terpene synthesis. The transcriptome analysis identified 19,673 differentially expressed genes (DEGs), including 726 TF-coding genes, 59 genes related to terpene synthesis, 66 ABC transporter genes, and 317 CYP450 genes. Small RNA sequencing identified 175 miRNAs, with 105 differentially expressed miRNAs (DEMs) targeting 2497 genes. Notably, pta-miR949, pta-miR946a-3p, and pab-miR3710 targeted PITA39236 (HDS), PITA24638 (GPPS), and PITA12789 (ACAT), respectively. Temporal analysis revealed that DEMs and DEGs in Profiles 7 and 13 significantly influenced terpene synthesis in slash pine. Specifically, bHLH genes (Novel9385, PITA08062, PITA23693, and PITA43216) in these expression profiles, as well as the pta-miR858a/b-PITA03784/PITA28059/PITA18794 (MYB) and pta-miR159c-Novel1571/Novel4202 (MYB) modules, play pivotal roles in slash pine terpene synthesis. This study, for the first time, revealed the regulatory role of miRNAs in slash pine terpene synthesis, providing a foundation for understanding the involvement of miRNAs in this process and offering theoretical support for future molecular breeding efforts aimed at enhancing resin yield in slash pine. • pta-miR949-PITA39236 (HDS), pta-miR946a-3p-PITA24638 (GPPS), and pab-miR3710- PITA12789 (ACAT) modules were directly related to the terpene synthesis of slash pine. • bHLH genes (Novel9385, PITA08062, PITA23693, and PITA43216), miR858a/b-PITA03784/PITA28059/PITA18794 module, and pta-miR159c-Novel1571/Novel4202) play pivotal roles in slash pine terpene synthesis. [ABSTRACT FROM AUTHOR]

Copyright of Bulletin of Botanical Research is the property of Bulletin of Botanical Research Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Forest Research is the property of Forest Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Micro- and nanoparticles of aluminum oxide (alumina) have been used to confer increased flammability to polymers. In the present study, different weight fractions of alumina nanoparticles were impregnated into a traditional softwood and the flammability of these treated woods was studied. Sodium polyacrylate (SPAC) was used as a surfactant and also as a positive control. The influence of the treatment in physical (apparent density), mechanical (static bending and hardness), and thermal (flame retardancy and thermal stability tests) characteristics were evaluated. The presence of alumina nanoparticles in the wood ultrastructure was confirmed by means of SEM/EDS analyses. Compared to the untreated pine wood and that wood impregnated with neat SPAC, the impregnation of alumina contents within 0.3–0.5 wt% reduced the flame spreading of the studied pine woods. Also compared to the untreated wood, similar thermal and mechanical properties were achieved. The studied pine wood became less flammable with alumina impregnation, and there was no detrimental effects to its mechanical properties. [ABSTRACT FROM AUTHOR]

Controlled-release fertilizers may improve productivity and mitigate environmental hazards in Southern pine plantations intensively managed for pinestraw harvesting. We examined the effects of pinestraw removal and fertilization with conventional and polymer-coated urea (PCU) on foliar, needlefall, and pinestraw nutrients and yields in a North Florida slash pine (Pinus elliottii Engelm.) plantation. Raking treatments (raked or nonraked) were applied annually in February 2014–2017. Fertilization treatments (PCU at 0, 28, 56, 140, or urea at 56 kg N ha−1 year−1) were applied annually in June 2014–2016. Four years of pinestraw removal did not affect needlefall mass or foliar and needlefall nutrient concentrations. The positive fertilization rate effect on pinestraw yield, needlefall mass, foliar, needlefall, and pinestraw total Kjeldahl nitrogen (TKN) and K concentrations, and on foliar and needlefall Ca concentrations increased in magnitude with subsequent applications. TKN, total P, and K concentrations were lower in needlefall and pinestraw relative to foliage by 65%–90%, whereas Ca concentrations were higher by 120%–180%. Three PCU applications at 140 N ha−1 year−1 increased three-year cumulative pinestraw yield over the control by 19% and TKN, K, Ca, and Mg removals by 49%, 86%, 24%, and 32%, respectively. Responses to PCU did not differ from urea. [ABSTRACT FROM AUTHOR]

The litter production, monthly dynamics of the litter, and effects of meteorological factors on litter production of two evergreen plantations（Acacia aulacocarpa and Pinus elliottii） in Changle Dahe Forest Farm, Fujian Province were investigated at the end of every month from January 2014 to December 2018. The results showed that the annual litter production of P. elliottii and A. aulacocarpa was 10.29 and 7.21 t·hm-2·a-1, respectively, whereas the annual litter production of P. elliottii was significantly higher than that of A. aulacocarpa. The order of litter size of P. elliottii litter was leaf litter> flower and fruit litter> branch litter> other litter> bark litter. The order of component size of A. aulacocarpa litter was leaf litter> branch litter> other litter> flower and fruit litter> bark litter, in which leaf litter was the main component of the two types of artificial forest litter, accounting for 70.00%（A. aulacocarpa） and 76.24%（P. elliottii) of the total litter. The maximum litter production of A. aulacocarpa and P. elliottii occurred in July and August, and the minimum litter production was between January and April. The correlation analysis of the two types of plantation litterfall production and meteorological factors showed that the litter production of the two types of plantations was significantly positively correlated with the average, the highest, the lowest temperature and sunshine duration（P<0.05). In addition, P. elliottii had a very significant positive correlation with extreme wind（P<0.01). [ABSTRACT FROM AUTHOR]

This study aimed to research the effects of forest (Pinus elliottii, slash pine) and shrub (Vitex trifolia) plantation on the soil microbial community in sandification land by using the Illumina Miseq sequencing of 16S rRNA and ITS rRNA genes and combined with the soil properties analysis to explore the driving factors. Finally, the results showed that the dominant bacterial phyla were Chloroflexi, Actinobacteria, Proteobacteria, and Acidobacteria; the shrub and forest plantation significantly increasing the proportion of Acidobacteria, while decreasing the proportion of Proteobacteria. For the fungal community, forest plantation was significantly changing the community structure at the phylum level that shifted from Ascomycota to Basidiomycota, and the ectomycorrhizal fungi take the most abundant with genus Rhizopogon predominant. The soil bacterial Chao1 and Shannon indices were significantly increased after revegetation, while the soil fungal Shannon diversity in the forest land that significantly correlated with soil total organic carbon and C/N was lower than that in the sandy and shrub land (p < 0.05). Besides, the bacterial and fungal communities were significantly affected by soil water content among all analyzed soil properties. Our results suggest that the revegetation significantly increasing the soil bacterial diversity that correlated with soil water content, total organic carbon, and available phosphorus, but there was no significant change in community structure. In contrast, slash pine plantation changes the fungal community structure and diversity dramatically. This change and possible succession of fungal community with stand age increasing may lead to the fragility of the plantation, which deserves continuous attention. [ABSTRACT FROM AUTHOR]

The use of wood residues in polymeric matrices is notable for promoting significant mechanical reinforcement of the matrix. Such composites are widely used in the development of new composite materials with tunable mechanical properties for a variety of applications. In this work, polymeric composites with epoxy resin as the polymeric matrix and Pinus elliottii wood residue as the reinforcement were obtained. The composites were obtained by adding wood residue (sawdust) with particle sizes of 0.30, 0.60, and 1.19 millimeters into an epoxy matrix to determine the best mechanical properties of the composite as a function of the particle size. The polymer/sawdust composites were characterized by scanning electron microscopy (SEM), Infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and stress–strain tests. SEM images revealed a smooth and homogeneous surface free of defects and holes. However, lateral profile images showed the presence of fine sawdust particles agglomerated and a considerable number of bubbles and cavities that could interfere in the mechanical properties of the composites. The FTIR characterization of the composite identified the main bands related to epoxy and lignin/cellulose chains. The results of the mechanical properties suggested that epoxy composites with sawdust can increase its tensile strength according to the sawdust particle size introduced into the matrix. [ABSTRACT FROM AUTHOR]

We examined a study plot sampled in the Conecuh National Forest of southern Alabama in 1999 and again in 2016 after stand thinning and persistent prescribed fire were used to improve habitat quality. These management activities were designed, in part, to enhance habitat quality for the gopher tortoise (Gopherus polyphemus), a species considered for protection under the Endangered Species Act because of range-wide population declines. Comparisons of vegetation structure were made at burrows that were active in 1999 and remained active in 2016, and at burrows that were active in 1999 but were classified as abandoned in 2016. Burrows that remained active across this span of time were distinctive in retaining a greater reduction of canopy cover and lacking hardwoods while having a high percentage of longleaf pine in neighboring canopy trees. Active burrows that were abandoned in 2016 were distinctive in possessing hardwoods among neighboring canopy trees, lacking pine seedlings in the midstory, and having increased frequency of legumes and decreased bare ground in the understory. All burrows experienced a decrease in canopy cover and an increase in distance to, and dbh of, neighboring canopy trees; all burrows also had a decrease in litter and non-legume forbs as well as an increase in shrub stems in the understory and midstory. These results indicate that management activities were successful in opening canopy cover but were largely unsuccessful at reducing shrub stems and increasing understory grasses and forbs. Nevertheless, burrows of gopher tortoises increased in abundance during this time period. The size distribution of these burrows changed from a unimodal distribution dominated by adults to a bimodal distribution indicative of increased juvenile recruitment. Thus, the gopher tortoise population increased in association with vegetation changes that suggest tortoises are more sensitive to shading caused by canopy closure than they are to available forage. [ABSTRACT FROM AUTHOR]

Recognising which life‐history factors can potentially explain the success of biological invasions is essential to understand why certain exotic species are more successful to invade a given system than others, and also to better predict invasion outcomes. We focused on the three most planted pine tree species in Southern Brazil – Pinus elliottii, P. caribaea and P. oocarpa – as a natural system to test the hypothesis that some key vital attributes – fecundity (number of seeds produced), seed viability, germinability, seedling growth vigour (biomass and stem length) – could be driving the greater invasion of P. elliottii in the region. We collected seeds of P. elliottii var. elliottii, P. caribaea subsp. hondurensis and P. oocarpa in two sites of similar climate and soil in the Cerrado biodiversity hotspot. Seeds were tested for viability and germinability, and seed production was estimated. Under laboratory conditions, we evaluated seedling survival, stem and root development, biomass production and mortality for each species. Although P. elliottii is regarded as the most successful invasive pine species in the Cerrado, it did not outperform the other pines in terms of seed viability, germinability and seedling survival, and it had the slowest growth. P. elliottii did produce, however, at least twice as many seeds as the other species. P. caribaea revealed high seed viability and seedling survival, the fastest seedling development, but low seed production. P. oocarpa showed the lowest seed viability, but fast root growth and very low seedling mortality. Our results suggest seed production is a key factor for P. elliottii invasion success. However, given the strong performance of P. caribaea and P. oocarpa for germinability and growth, we emphasise the risk of both species also becoming successful invaders in the Cerrado. We highlight the need for constant monitoring of emerging pine individuals in native ecosystems to avoid future invasions. [ABSTRACT FROM AUTHOR]

The successful manufacturing of glulam from several important Australian commercial timbers is quite challenging due to difficulties in gluing. Improvements in adhesive bond performance of spotted gum, Darwin stringybark, and southern pine timber have been achieved using alternative pre-gluing surface machining methods, e.g., face milling and sanding-post planing, when compared to conventional planing methods. In order to improve the understanding of the effects that different surface machining methods have on adhesive bond performance, this study used micro X-ray computed tomography and microscopy to assess key adhesive bond criteria. There was a considerable loss in the amount of adhesive after the wet and dry test cycles for all species. There was also an extremely high frequency of voids in the glue lines for all species, which would negatively impact bond strength and durability. Face mill prepared timber boards resulted in thicker glue lines and greater resistance to adhesion loss, compared to boards prepared via planing. For the two hardwood species, face milling also resulted in greater adhesive penetration; however, for southern pine, there were no significant differences in adhesive penetration between the three surface machining treatments. Adhesive penetration was much deeper in southern pine compared to spotted gum and Darwin stringybark. [ABSTRACT FROM AUTHOR]

Forests of Iran located on the Southern border of the Caspian Sea cover 1.9 million hectares. The Caspian forests are divided into four separate forestry areas. One of these being Guilan influx area with total area of 565000 hectares. About 30 to 40 percent of Guilan province forests are suitable to short rotation forestry for afforestation. Slash pine (Pinus elliottii) is one of the main exotic species planted in the Guilan province. The objectives of this research were to estimate: stand parameters, form factors and a provisional volume table of Slash pine planted forest stands. A total of 142 individual trees were randomly sampled. Individual tree variables such as: dbh, height, volume, and form factors (f13, fm, f0.1 and fh) were measured and analyzed. The site index quality of study area, were broadly compared with stands of site index in the southeast USA. The results were shown that the site index quality at the study area in the north of Iran in agreement and parallel with stands of site index is 21m (63 Ft.) in the southeast USA. Therefore, operation of Slash pine is satisfied as short rotation forestry in the Guilan province of Iran.

Pinus elliottii is an evergreen coniferous tree. It is considered a potential species for ecological restoration in the Three Gorges Reservoir Area (TGRA). To classify the effects of different degrees of flooding stress in winter on nutrient accumulation in Pinus elliottii after experiencing early drought stress in summer, simulated water treatments of deep submergence (DS) and moderate submergence (MS) were imposed after the summer drought period. The results indicated that the survival rate of seedlings was 95.3%, and the accumulation trend of the flooded plants was rapid at an average rate of 1.99 ± 0.33% in the early stage of flooding (stage I: 0–7 days), a rapid release rate in the second stage (stage II: 7–60 days), and an average rate of only 0.07 ± 0.04% in the later stage (stage III: 60–150 days). After 150 days of flooding, the leaves of Pinus elliottii released an average of 7.156 ± 0.4 g kg−1 of organic carbon, 8.839 ± 0.6 g kg−1 of nitrogen, 0.781 ± 0.1 g kg−1 of phosphorus, and 2.985 ± 0.3 g kg−1 of potassium of macroelement content, and an average of 0.201 ± 0.03 g kg−1 manganese, 0.147 ± 0.04 g kg−1 iron, 0.002 g kg−1 copper, and 0.023 g kg−1 of zinc of microelement contents. Our results also demonstrated that after 150 days of flooding, the C/N, N/P, and C/P ratios of the nutrient element content of Pinus elliottii in the water-level fluctuation zone of the TGRA were 0.810%, 11.32%, and 9.16%, respectively. The absorption and release of nutrients under water flooding are generally divided into three stages: first, the early storage stage (the first stage: 0 to 7 days, optional), then the rapid release (the second stage: 7 to 60 days), and the later stage slow release phase (third stage: 60 to 150 days). Water flooding reduced the contents of C, N, P, and K and affected the absorption of nutrient elements in the plant. At the same time, soluble Mn2 + and Fe2 + over absorbed during flooding could cause toxicity to leaf tissues. At the same time, Pinus elliottii selected to reduce Cu in leaves to ensure that the root has a strong redox capacity and improve nitrogen utilization, thereby preventing the long-term flooding of toxic cations and acid substances. Taken together, our results conclude that increased drought stress can reduce the ability of Pinus elliottii seedlings to withstand flooding stress; the seedlings of Pinus elliottii can maintain their growth by accumulating certain nutrient elements under submerged conditions, which implies that this species would be a suitable candidate for reforestation in the TGRA because of its tolerance to submergence. [ABSTRACT FROM AUTHOR]

Pinus elliottii wood from different radial locations within trees was used to prepare two-layer preservative-treated wood joints with alkaline copper quaternary preservative and emulsion polymer isocyanates (EPI) or resorcinol-phenol-formaldehyde (RPF) adhesives. The radial variations in shear strength and wood failure percentage were analyzed. Radial variations in wood density and average penetration depth (AP) of adhesives were investigated to establish relationships between shear strengths and characteristics of bonded joints. The shear strengths of EPIand RPF-bonded joints showed similar increasing trends from pith to bark, and they varied in ranges of 2.92 to 8.13 MPa and 2.03 to 7.12 MPa, respectively. The wood failure percentage of EPI joints (93% to 100%) had no significant differences in all the radial locations, but that of RPF joints (60% to 100%) showed a clear decreasing trend from pith to bark. High positive linear correlations were found between the shear strengths and wood density, and Pearson's correlation coefficients for EPI and RPF were 0.934 (p < 0.01) and 0.931 (p < 0.01), respectively. Wood density is a very important factor influencing radial variations of bonding strengths. The correlation between the AP and shear strength was not significant at the 0.05 level. [ABSTRACT FROM AUTHOR]

The aim of this work was to verify the ability to use the Particle Image Velocimetry technique for measurements of dimensional variations resulting from wood retractability of Pinus elliottii wood, initially saturated and with the surface marked with multiple dots of ink randomly distributed, was used in this work to apply the Particle Image Velocimetry technique. The specimens were dried and images were captured during the process. The images obtained were processed by the Particle Image Velocimetry algorithm and the deformations that occurred were calculated. For comparison, a conventional method (pachymeter) was used to measure the dimensions of the specimen during drying. The variation in dimensions obtained on the surface of the specimens from the Particle Image Velocimetry technique was 2,28 % for the radial direction and 0,20 % for the longitudinal direction of the fibers. With the standardized method, these values ​​were 2,18 % for the radial direction and 0,21 % for longitudinal. The reduction in the average area of ​​the specimens was 3,85 % by the Particle Image Velocimetry technique and 3,77 % by the conventional methodology. It was concluded that the Particle Image Velocimetry technique was able to accurately measure the displacements on the surface of the Pinus elliottii specimens, resulting in values ​​statistically similar to those reached through the use of the conventional measurement method, demonstrating its reliability.

En este artículo se presentan y discuten los resultados de un proyecto orientado a investigar las deformaciones bajo carga de larga duración, y la recuperación luego de la descarga, en vigas de pino resinoso de rápido crecimiento (Pinus taeda y Pinus elliottii) cultivado en el noreste de Argentina. La investigación empírica se llevó a cabo en un local sin climatización con el propósito de incorporar fluctuaciones de la temperatura y la humedad relativa ambiente durante el período de carga, utilizando una muestra integrada por 14 vigas de muy variada calidad. Las deformaciones se registraron bajo carga constante durante 392 días y luego libres de carga durante un período de recuperación de 28 días. No obstante las variaciones climáticas producidas, se encontró una destacada similitud entre el valor de la deformación inicial instantánea de cada viga y el de su recuperación instantánea luego de la descarga. Los resultados también probaron que, independientemente de la calidad de la madera, el desarrollo de las deformaciones diferidas se mantiene estable y las reglas de diseño resultan eficaces para calcular su valor si el nivel de tensión en la viga es inferior al 35 % de su resistencia instantánea.

In order to make the rapid and large-scale propagation of fast-growing varieties of Pinus elliottii, the induction and proliferation of embryogenic callus were studied. The immature zygotic embryos (with endosperm) of ten P. elliottii families were used to systematically study the effects of different factors on the induction efficiency of embryogenic callus, including genotype, the developmental stage of zygotic embryos, basic medium, types and concentrations of plant growth regulator ( PGR) . At the same time, the proliferation conditions of embryogenic callus were discussed. The esults were as follows: The genotype, the developmental stage of zygotic embryos, basic medium and types and concentrations of plant growth regulator (PGR) all had different degrees of influence on the induction of embryogenic callus. Embryogenic callus were induced in all ten genotypes, of which the induction rate of Genotype 2 was the highest, reaching 25.37%; In the stage of zygotic embryo development, the induction rate of cones at the multiple embryo stage was the highest; Among the four basic media, the induction effect on DCR basic medium was the best; The induction rate of 2,4-D 2.0 mg L+KT 2.5 mg L-1 was the highest, reached 27.78%. The proliferation of embryogenie callus for P. elliottii was achieved on DCR medium, supplemented with 2,4-D (0.5 mg L-1), KT (1.0 mg - L-1), CH (500 mg L) and Gin (300 mg L-1). This study laid a foundation for further developing mature embryo induction and plant regeneration of fast-growing varieties of P. elliottii. [ABSTRACT FROM AUTHOR]

Copyright of Forest Research is the property of Forest Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Drying has a major impact on the viability of sawn timber production, particularly through its influence on productivity, energy usage, and product quality. Traditionally, plantation-grown southern pine structural grade timber from Australia has been dried using high temperature (≥ 180 °C) conventional batch kilns. However, the Australian industry is showing increasing interest in continuous drying kilns because of reported cost savings and potential improvements in product quality. This study investigated the differences between continuous drying and conventional drying schedules on the radial permeability, wettability, gluability, and treatability of southern pine timber from Queensland plantations. The high temperature drying resulted in significantly lower liquid permeability compared to low temperature drying; however, there were no significant differences between drying schedules for gas permeability. For combined wood surface and core data, there were no significant differences in liquid permeability between low temperature drying and continuous drying or between continuous drying and high temperature drying schedules. For earlywood after surface machining, continuous drying resulted in the greatest wettability (based on K-values), whereas for latewood after surface machining, low temperature drying produced the greatest wettability. Earlywood had greater wettability compared to latewood. Continuous drying resulted in better gluability and treatability compared to conventional drying schedules. [ABSTRACT FROM AUTHOR]

Southern pine and spotted gum are two of Australia's most important locally produced commercial timbers. However, internationally, they are amongst the most problematic species to glue cost-effectively, especially for sawn-laminate-based structural engineered wood products, such as glulam and cross-laminated timber. This study investigated the efficacy of different pre-gluing wood surface machining preparations on the tensile shear strength of lap shear samples prepared from both species. Surface machining methods tested included planing, face milling, and sanding post-planing with 40 and 80 grit sandpaper. Wood face milling is not currently used commercially in Australia and has not previously been adequately tested on Australian commercial timbers to improve wood adhesion. Planing is currently the most common method used internationally for preparing wood surfaces for gluing. For both species, face milling with fast feed speed (45 m/min), slow cutter speed (57 m/s), and sanding treatments post-planing resulted in significantly higher tensile shear strength compared to planing for lap shear samples that had been subjected to an accelerated weathering process. Performance differences in tensile shear strength between surface machining methods are likely to be related to the effects of these machining methods on surface roughness, fibrillation, and sub-surface cell damage. [ABSTRACT FROM AUTHOR]

Question: The Cerrado represents the largest savanna of the Neotropics. Nowadays, this ecosystem is threatened by the afforestation by monocultures, such as Pinus spp., leading to serious damage to native herbaceous species. Afforestation of savanna ecosystems can affect their ability to regenerate naturally, which relies on different strategies, such as resprouting from below‐ground bud‐bearing organs. Therefore, we investigated the impact of ca. 50 years of Pinus elliottii plantations, compared to undisturbed areas of Cerrado savanna, estimating the bud bank size by counting buds on bud‐bearing organs. We hypothesized that long‐term P. elliottii plantations negatively affected the bud‐bearing organs, leading to decreases in the bud bank. Location: Cerrado savanna areas and Pinus elliottii plantations, southeastern Brazil. Methods: Open savanna areas (hereafter Cerrado) and "P. elliottii plantations" were considered the vegetation types. Within each vegetation type, we designated three areas. In each area, we established 10 plots (1 m2). For each plot, the bud bank was sampled from 5 cm above to 10 cm below ground level in subplots (0.25 m2). We developed generalized linear mixed models (GLMM) for each response variable to test differences between both vegetation types. Results: The presence of the P. elliottii plantations for almost 50 years has led to massive reductions in the bud bank size and the number of bud‐bearing organs, when compared to the Cerrado areas (p < 0.0001). Conclusions: The reduction in the below‐ground bud‐bearing organs density led to decreases in the bud bank and thus, loss of resilience in these areas. Regeneration in planting areas may not occur naturally after the removal of the plantations. Restoration of the herbaceous layer after P. elliottii removal will rely on the introduction of a new source of propagules through active interventions. [ABSTRACT FROM AUTHOR]