Eucalyptus Saligna Research Articles (Page 1)

IntroductionThe greenhouse gas balance is a central theme in discussions related to forest ecosystems. In this context, the present study evaluated the impact of five eucalyptus harvest residue management systems on atmospheric C-CO2 retention in soil, greenhouse gas (GHG) emissions, and the global warming potential (GWP) in Eucalyptus saligna plantations.MethodsThe management systems examined were: AR - all harvest residues retained on soil; NB - harvest residues kept on soil, except bark; NBr - harvest residues kept on soil, except branches; NR - all harvest residues (bark, branches, leaves) removed; NRs - all residues from the previous rotation and new plantation litter removed using shade cloth. Soil emissions of nitrous oxide (N2O) and methane (CH4) were monitored over 12 months (October 2016 to October 2017). Soil samples were collected to a depth of one meter to assess atmospheric C-CO2 retention. Results and discussionAnnual N2O emissions were low (0.11–0.23 kg N-N2O ha−1 year−1) and showed no clear relationship with the amount of nitrogen added through residues. The soil consistently functioned as a methane sink across all management systems, with CH4 fluxes ranging from –2.56 to –3.91 kg C-CH4 ha−1 year−1. The highest rate of C-CO2 retention in soil (–5,540 kg C-CO2 ha−1 year−1) was observed under the AR management system, while the lowest (–1,752 kg C-CO2 ha−1 year−1) occurred under the NRs system. AR management also resulted in the lowest global warming potential (–33,946 kg C-CO2 ha−1 year−1), primarily due to soil C-CO2 retention (15.43%) and carbon accumulation in biomass and wood products (84.57%). These findings demonstrate that retaining eucalyptus harvest residues in subtropical sandy soils, in conjunction with carbon sequestration in wood products, constitutes an effective forest management strategy for mitigating global warming.

A silvicultural regime refers to the planned sequence of treatments applied to a forest stand, which mainly includes pruning and thinning regimes. The latter is a silvicultural practice that is important for the management of forest growth, composition, structure, and health. Despite the ecological and silvicultural importance of thinning, its limited application in plantation forests has constrained the effective management of woody species density and abundance. Thus, the aim of this research was to assess the influence of the thinning regime on woody species density and abundance. This study focused on Eucalyptus saligna, Cupressus lusitanica and Pinus patula as the woody species that are harvested for timber in the Kimondi forest. The study applied a cross-sectional descriptive study design. Systematic sampling was used in collecting primary data. Data were analysed using box plots, Analysis of Variance and Duncan multiple range test. The box plots showed Eucalyptus saligna having the highest median density and the widest interquartile range, indicating both a greater abundance and variability across sampling sites. Cupressus lusitanica and Pinus patula had a moderate median density with a narrower distribution, indicating lower variability. Analysis of variance revealed a highly significant difference in tree abundance and density across the thinning regime (p = 0.000), with an effect size (Eta² = 0.7519), indicating that 75.19% of the variation of woody species density and abundance can be explained by the thinning regime. Duncan’s Multiple Range Test confirmed that mean abundance varied significantly across the thinning regime. The study concluded that a thinning regime can improve the density and abundance of woody species, Eucalyptus saligna, Cupressus lusitanica, and Pinus patula. We recommend that forest managers in plantation forests adopt thinning regimes to improve woody species density and abundance.

This study applied six failure criteria to estimate the shear strength of wood adhesive joints subjected to tension and compression loads as a function of fiber inclination. Shear stresses in the adhesive line were determined through experimental tests using specimens obtained from 12 Eucalyptus saligna beams. These specimens were prepared with variable fiber inclinations (0º, 15º, 30º, 45º, 60º, 75º, and 90º) relative to the load application, following the NBR 7190 standard. The experimental results were statistically analyzed in conjunction with the six failure criteria (Hankinson, DIN 1052, Tsai-Hill, Hyperbolic, Keylwerth, and Karlsen), allowing for the adaptation of the models to determine the shear strength of the adhesive line as a function of fiber inclination. In their original form, the Hankinson, DIN 1052, Tsai-Hill, and Hyperbolic models did not show statistical significance (p < 0.05). However, after modifications, all models demonstrated statistical significance, with the best fits being provided by the DIN 1052, Keylwerth, Hankinson, Karlsen, Hyperbolic, and Tsai-Hill models, in order of significance. Due to ease of application, the most recommended models for predicting the shear strength values of the adhesive line under compression and tension, as a function of fiber inclination, are the DIN 1052 and Hankinson formulas.

Mini-tunnel and season influence in clonal garden on the production of clonal seedlings for two subtropical clones: Eucalyptus saligna and Corymbia torelliana × Corymbia citriodora

Forests remain the major habitats for wildlife in many parts of the world. However, game damage to forest plantations remains a threat to the development and management of forests. The wildlife debarks, bark strip, uproot, break branches, trample, browse plantation forest tree species and graze on grassland. There is little and conclusive information on the impact of game damage on forest in Kenya. The aim of the current study was to assess the game damage to forest plantations by wildlife at Hombe Forest Station. Primary data was collected using an observation schedule complemented with secondary data from the Kenya Forest Service and Kenya Wildlife Service. Eighteen Permanent sample plots (PSP) of one (1) Ha each were established in three sites. The study established that many of the dead and drying trees can be attributed to game damage. The two major game species were the elephants (<i>Loxodonta africana</i>) and buffaloes (<i>Syncerus caffer</i>). It was established that all tree species showed signs of damage from wildlife, <i>Cuppressus lusitanica</i> damage was highest in site C compared to site B and A (One-Way ANOVA; F<sub>(2)</sub> = 16.234, P < 0.001), the differences in game among the site may be attributed to higher density of animals observed in site A compared to the other sites. The major impacts to forest are trunk breaking and uprooting of Eucalyptus, bark stripping, debarking, and knocking down of Cypress. Forest destruction was due to game damage. It was found out that <i>C. lusitanica</i> experienced the highest impact on game damage especially debarking/bark stripping which accounted for 74.7% while broken branches were 17.8% and browsing 7.5 %. In terms of species preference to game damage <i>C. lusitanica</i> was leading with 93%, with Mexican green ash (<i>Fraxinus pennsylvanica</i>) at 5% and <i>Vitex keniensis</i> 2.0%. Forest plantations of <i>C. lusitanica </i>were the most destroyed species, while <i>Eucalyptus saligna</i> were the least destroyed. The Kenya Forest Service needs to fence industrial forest plantations to avoid losing all the investments in establishing, management and protection of plantations. The planting of non-palatable industrial forest plantation tree species like <i>F. pennysilyvanica</i> Mexican green Ash and <i>V. keniensis</i> Meru Oak are recommended in the game prone areas.

Background: Studies show that forest uniformity has a direct correlation with productivity, and uniformity measures can serve as indicators of the silvicultural quality of plantations. In this context, this work aimed to determine uniformity and survival in young Eucalyptus sp. plantations using attributes obtained from passive sensors boarded on Unmanned Aerial Vehicles (UAV). Methods: Tree height was underestimated by the UAV compared to those measured in the Quality Forest Inventory (QFI). Thus, a correction factor applied to size classes was proposed to estimate these heights. The plantations’ uniformity was obtained through the uniformity indices (UI). The UIs were spatialised and integrated, resulting in two uniform surfaces, with and without planting failures. Results: The UAV survival estimates did not show significant differences compared to the inventory estimates at the 1% or the 5% significance levels. The classification of uniformity surfaces showed that the Eucalyptus saligna Sm plantation was the least uniform compared to the E. grandis W. Hill × E. urophylla S. T. Blake plantations. Conclusions: Measures of survival and uniformity by the UAV can be jointly employed to generate uniformity surfaces and to determine the areas that need more attention from silvicultural management.

This study evaluated the phenology of Butia catarinensis in shrubby Restinga and under the understory of eucalyptus monoculture (Eucalyptus saligna and Eucalyptus paniculata) along the southern coast of Santa Catarina, Brazil. Phenological data were collected monthly over a one-year period. Butia catarinensis exhibits an annual, asynchronous reproductive cycle, showing higher flowering and fruiting rates in spring and summer, with reduced reproductive activity during winter. Precipitation had minimal influence on its reproductive cycle; however, higher temperatures and increased solar radiation positively correlated with the development of green and ripe fruits year-round. The lack of significant differences between the two study environments indicated that the eucalyptus monoculture microclimate did not affect flowering and fruiting quantities of B. catarinensis, though it may have influenced phenophase timing, potentially accelerating, delaying, or extending these events.

(1) Background: Nature-based solutions (NbS), particularly through forest biomass, are crucial in mitigating climate change. While forest plantations play a critical role in carbon capture, the absence of species-specific biomass estimation models presents a significant challenge. This research focuses on developing allometric models to accurately estimate the aboveground biomass of Eucalyptus saligna Sm in Ecuador’s Lower Montane thorny steppe. (2) Methods: Conducted at the Tunshi Experimental Station of ESPOCH in Chimborazo, Ecuador, the research involved 46 trees to formulate biomass predictive models using both destructive and non-destructive methods. Sixteen generic models were tested using the ordinary least squares method. (3) Results: The most effective allometric equation for estimating six-year-old E. saligna biomass was Ln(B) = −0.952 + 1.97∗Ln(dbh), where B = biomass in kg/tree, and dbh = diameter at breast height in cm. This model represents a valuable contribution to improve biomass and carbon estimates in mitigation projects in Ecuador. (4) Conclusions: The tested models stand out for their simplicity, requiring only dbh as input, and demonstrate high accuracy and fit to contribute to the field of climate change mitigation.

O aperfeiçoamento da estimativa da produção florestal é indispensável para o emprego das florestas plantadas como fonte de energia renovável. Nesse sentido, objetivou-se desenvolver modelos simultâneos para a estimativa da produção de biomassa por componentes da árvore em povoamentos clonais de Eucalyptus saligna e híbridos de Eucalyptus grandis × Eucalyptus urophylla. A quantificação da biomassa seca acima do solo foi realizada em povoamentos com idade de 7 anos, em que modelos alométricos foram ajustados independentemente para estimar a biomassa dos componentes fuste, galhos, folhas e casca em nível de árvore para E. saligna e E. grandis × E. urophylla. Os ajustes simultâneos foram efetuados por meio regressões aparentemente não relacionadas, visando assegurar a aditividade das predições parciais por componente à estimação da biomassa total acima do solo. A qualidade estatística foi realizada por meio de medidas de erro e análises gráficas. Houve melhoria da qualidade dos modelos para biomassa de galhos para E. saligna e fuste para E. grandis × E. urophylla, comparativamente aos ajustes independentes. Por outro lado, houve redução do erro da estimativa dos componentes fuste e casca para E. saligna e fuste e galhos para E. grandis × E. urophylla. Observou-se, para ambas as espécies, erros inferiores a 10% e ausência de tendências na estimativa da biomassa total. Os modelos desenvolvidos via equações simultâneas apresentaram resultados estatisticamente satisfatórios, especialmente para o componente fuste, o qual expressa maior contribuição à biomassa total. Ademais, houve melhoria ao garantir a aditividade das estimativas parciais na estimativa da biomassa total.

This study aimed to model and identify the most productive cutting methods of tree plantations by comparing a forward felling technique (C) with sideways techniques outside (A and D) or inside cutting edge (B and E). Drone video material of each tree was analyzed by comparing time distribution of work phases. The relation between this input data and harvester production data was analyzed by regression models. A quadratic model predicted productivity precisely (R2 = 0.95) and explained the effective-hour productivity in cutting cycle with dummy variables of harvesting conditions. The productivity was explained by tree size and cutting cycle time, while effects of operator and harvester were eliminated by statistical analysis. In loblolly pine (Pinus taeda L.) plantations on flat terrain, cutting method B was 4.8 m3/E0h (effective working hour) more productive than method A, and 6.7 m3/E0h than method C. In Sydney blue gum (Eucalyptus saligna Sm.) plantations, cutting method E was 1.8 m3/E0h more productive than cutting method D on sloping terrain. Of the time-cycle variables, time consumption of the “moving of tree” changed significantly between the cutting methods, of which the ones that used the sideways felling technique inside cutting edge were most efficient. This quadratic modeling structure can be recommended for precise studies in similar harvesting conditions.Graphical

O Brasil se destaca como o maior produtor de celulose de fibra curta do mundo e, apesar dos resultados alcançados através do cultivo do eucalipto, outras culturas, como as espécies e híbridos do gênero Corymbia estão sendo estudados em programas de melhoramento genético. Neste contexto, o presente trabalho teve como objetivo avaliar a qualidade da madeira e o ranqueamento de dez clones híbridos de Corymbia torelliana e Corymbia citriodora para a produção de celulose kraft, tendo como controle um clone comercial de Eucalyptus saligna. A qualidade da madeira foi avaliada quanto à composição química, densidade básica e desempenho na produção de celulose. Na polpação kraft foram avaliados: o rendimento depurado, número kappa, teor de rejeitos e consumo específico de madeira. Todos os clones híbridos do gênero Corymbia apresentaram densidade básica superior ao tratamento de controle, com resultados variando de 509 a 607kg/m³. Os híbridos de Corymbia apresentaram extrativos totais variando de 2,53 a 8,16%, lignina total de 25,84 a 28,42%, cinzas de 0,5 a 1,17% e holocelulose de 65,35 a 70,84%. O híbrido de Corymbia com melhor desempenho na polpação obteve rendimento depurado de 53,24%, número kappa de 22,2, teor de rejeitos de 0,91% e consumo específico de 3,11 m³/tsa. O estudo permitiu realizar o ranqueamento e indicar os clones com melhor qualidade da madeira para a produção de celulose kraft.

This study reports for the first time the fingerprinting extractives analysis of the indigenous wood species of Podocarpus totara from New Zealand, Eucalyptus saligna from Australia and Pinus radiata imported from California, USA and grown in New Zealand. We evaluated the use of analytical techniques for wood species discrimination. We compared the chemical fingerprinting of extractive compounds obtained using traditional chromatographic techniques with direct analysis in real-time–time of flight-mass spectrometry (DART-TOF-MS) with the auxiliary of chemometrics and principal component analysis. The traditional wet chemistry analysis of wood extracts provided a comprehensive characterisation of all extractive components. However, the more eco-friendly, sustainable and faster DART-TOF-MS technique effectively distinguished between wood species when heartwood and sapwood samples were combined. Notably, neither wet chemistry nor DART-TOF-MS could clearly differentiate between heartwood and sapwood within the same wood species. DART-TOF-MS analysis demonstrates potential as a reliable quality control tool for identifying wood species necessary in commercial and timber trading markets as well as for detecting the illicit trade of counterfeit wood products.

Coppicing is a forest management technique that induces the production of new shoots from stumps to start a novel forest cycle. This study aimed to compare anatomical characteristics between coppice and high stem. Wood samples were collected from clones of Eucalyptus grandis × Eucalyptus camaldulensis, E. grandis × Eucalyptus urophylla, and Eucalyptus saligna grown in one-stem coppice, two-stem coppice, and high stem. Anatomical parameters of fiber dimensions such as vessel diameter and frequency were analyzed. Anatomical elements were quantified by cell coloring and point counting (324 points) methods. The anatomical structure of coppiced trees was found to vary according to eucalyptus species. Fiber length and vessel frequency were similar between coppice and high stem. Coppiced wood showed higher fiber cell wall thickness and vessel diameter. Adaptation to coppicing resulted in a specific anatomical composition for each species, such as a higher quantity of parenchymal cells in E. saligna and a lower quantity of fibers in E. grandis × E. urophylla. The point sampling method provided inaccurate results, differing significantly from the cell coloring method. The findings underscore that the decision to manage forests under a coppicing system should be approached with caution, as it is crucial to understand the resulting anatomical alterations to mitigate potential industrial issues.

The search for sustainable energy solutions is essential for communities that still rely on wood-burning stoves, a common practice in many regions of Brazil. The efficient choice of stoves and fuels is challenging because of the environmental impact of wood consumption and associated emissions. Despite studies on the efficiency of wood-burning stoves, there is a gap in the robust and automated multi-criteria methodologies application to comprehensively compare the efficiency of cookstoves and fuels as well as wood consumption and heat output. This study carried out the ordering and ranking of nine eucalyptus fuels, based on criteria such as efficiency, calorific power, and wood consumption of the improved technology stove. The selected eucalyptus species were Eucalyptus saligna Sm., Corymbia citriodora (Hook.) K.D. Hill & L.A.S. Johnson, Eucalyptus urophylla S.T. Blake, Eucalyptus grandis W. Hill ex Maiden, Eucalyptus grandis W. Hill ex Maiden x Eucalyptus urophylla S.T. Blake, Eucalyptus propínqua H. Deane & Maiden, Eucalyptus pellita F. Muell., Eucalyptus camaldulensis Dehnh., and Eucalyptus tereticornis Sm. Three ordinal multi-criteria decision methods (Borda, Copeland, and Condorcet) were applied, with automated implementation via scripts in the R software, enabling graphical analysis and detailed comparisons. The results showed that Eucalyptus pellita firewood was the most efficient and sustainable option. Moreover, it was concluded that the proper selection of fuels can significantly reduce wood consumption, mitigate environmental impact, and offer more sustainable alternatives for cookstoves.

Mutation induction by gamma rays in clonal plantlets of Eucalyptus saligna and Eucalyptus dunnii: dose adjustment and application of repeated pruning

<p><strong>Background</strong>. Soil aggregates represent a major indicator of soil fertility as they are important components of soil C protection. However, in the Democratic Republic of Congo, the choice of tree species being integrated into crop farms influence the type of soil macrofauna beneath these agroforestry trees with effect on soil aggregates and carbon fractions. <strong>Objective</strong>. To assess the combined effect of diverse tree species alongside earthworms and termites on soil aggregation and soil organic C. <strong>Methodology</strong>. Soil samples were collected from five agroforestry systems comprising <em>Eucalyptus saligna,</em> <em>Grevillea robusta</em> and <em>Ficus benghalensis</em> (an indigenous tree) woodlots, an agricultural farm (beans) and a natural forest in four different locations. Soil aggregates and soil organic C were analysed in the laboratory following standard procedures. The analyses of variance and correlations were carried out using R programming software. <strong>Results</strong>. A significantly higher proportion of large macroaggregates was recorded in soil under natural forest (13.1 %) whereas microaggregates were significantly low in soils under natural forest. For all the categories of aggregate-associated C, natural forest recorded the highest values while beans had the lowest values. The same trends were observed for labile C with 22.9 g kg<sup>-1</sup> in soil under natural forest and 9.7 g kg<sup>-1</sup> in soil under beans. <strong>Implication</strong>. The high levels of soil aggregates as well as carbon fractions recovered from natural forest clearly show the significance of a well-diversified tree-based farm. <strong>Conclusion</strong>. Therefore, it is advisable to consider a large diversification of tree species on farms to sustain and maintain a better soil quality.</p>

Penetrometers and penetrographers are widely used to measure soil resistance to penetration, but the results are associated with other soil properties (such as bulk density, water content, and particle size distribution). Thus, for an adequate interpretation of results, site-specific studies are necessary to identify which properties are more related to soil resistance. We aimed to measure the resistance to penetration of a Typic Paleudalf under distinct soil uses and to identify soil properties that influence soil resistance. The soil uses in this study included anthropized forest (composed of tree and shrub species), pasture (5-year-old pasture), Eucalyptus 20 (a 20-year-old Eucalyptus saligna stand), and Eucalyptus 4.5 (a 4.5-year-old Eucalyptus saligna under the second rotation). Soil resistance to penetration was measured with an impact penetrometer, and the data were correlated with other physical and mechanical properties of soil, such as the particle size, soil moisture, air permeability, saturated hydraulic conductivity, porosity, bulk density, precompression stress, and compressibility index. We observed that a resistance of 1.3 MPa matches with other soil property values corresponding to soil compaction, and values greater than 1.3 MPa were verified at depths of 0–8 cm for pasture and 8–30 cm for Eucalyptus 4.5. Analyzing all soil uses together, the correlation was significant (p < 0.05) with gravel (r = 0.34), silt (r = −0.32), clay (r = 0.26), gravimetric moisture (r = −0.27), macroporosity (r = 0.24), and soil bulk density at the end of the compressibility test (r = 0.27). The penetrometer is useful for evaluating the physical conditions of soil, but we highlight that soil resistance is influenced by factors such as particle size and soil moisture, as examples. We recommend using a set of soil properties for a better interpretation of penetration resistance data and to support decision-making regarding soil management.

Global forest plantations are expanding, causing land-use changes and impacting the water cycle. This study assesses whether eucalyptus plantations reduce groundwater levels compared to grasslands in paired subtropical watersheds. The hydrological dynamics of surface and subsurface water were compared in three small watersheds in southern Brazil, mainly occupied by Eucalyptus saligna (Es-W, 79.9 ha), Eucalyptus benthamii (Eb-W, 82.1 ha), and degraded anthropized natural grassland (G-W, 109.4 ha). Rainfall, flow, and piezometric levels were monitored. Runoff, evapotranspiration, and water balance in the soil profile were estimated, and the subsurface environment was characterized using electrical resistivity tomography. During higher accumulated rainfall, water surplus increased for all watersheds. In the wet period (accumulated rainfall of 1098.0 mm), evapotranspiration was higher for eucalyptus (624.3 mm for Eb-W and 512.5 mm for Es-W) than for the grassland watershed (299.5 mm), resulting in the highest runoff in G-W (649.6 mm). During the dry period (accumulated rainfall of 478.5 mm), water deficit and withdrawal were mainly observed in forested watersheds, decreasing groundwater. Combining water balance and electrical resistivity tomography estimations results in a better understanding of the hydrological dynamics in paired watersheds with different land uses. This information is useful for developing best-practice management strategies for sustainable water resource use and forest production.

Abstract Atmospheric particulate matter (PM) is the most inhaled hazardous air pollutant that can cause adverse health impacts. Plants can remove such contaminants and act as biological filters through phytoremediation. In this study, we screened 12 Australian native species (two deciduous trees, three evergreen shrubs, and seven evergreen trees) growing in three regions to determine their potential in accumulating leaf surface (SPM) and in‐wax PM (WPM). Among the screened species, Lagunaria patersonia (139.22 μg cm−2) was the most effective PM accumulator, followed by Ficus obliqua (131.02 μg cm−2). L. patersonia is an Australian native tree with a dense crown that can efficiently trap PM due to air turbulence between its leaves and branches; broad leaves with a rough texture enhance the plant's ability to trap PM. On the contrary, morphological characteristics like evergreen leaves with hairy appendages may act as an efficient trap for PM in F. obliqua. Due to smoother leaves, the least effective species were F. rubignosa and Eucalyptus saligna. In addition to leaf shape, leaf structures and micromorphology influence PM accumulation. For instance, Pittosporum undulatum accumulated more PM due to its wrinkled and folded leaf structures despite a significantly lower waxes layer. The findings highlight the importance of planting efficient PM accumulator species to shield vulnerable areas from pollution and decrease human exposure to pollutants. The sink capacity of these species can be used in urban tree planning to combat air pollution and improve air quality.

The objective of the study was the evaluation of survival and productivity indicators in different species/hybrids of Eucalyptus in the adult stage, as well as the vegetative rescue of adult trees and cuttings, testing for species/hybrids, concentration of growth regulator and substrates in rooting. In the evaluation of species/hybrids, height (m), diameter at breast height (DBH, cm) and individual volume (m3 per individual) were measured, and survival was evaluated. In the vegetative rescue treatment, the number of shoots produced at 90, 120 and 210 days was evaluated. In the cutting experiments, the species that produced rescue shoots were tested, in addition to indole-3-butyric acid (IBA) doses (0, 1 500, 3 000 and 4 500 mg L−1) and four substrates for rooting cuttings. The experiments of IBA doses and substrates were carried out using Eucalyptus saligna plants. In the cutting experiments, after 120 days of cultivation, the following variables were evaluated: callus formation (%), survival (%), rooting (%), number and length of roots. The best results regarding survival and quantitative variables of the species/hybrids were obtained for E. dunnii, E. dunnii × E. grandis and E. pellita. In the vegetative rescue, E. dunnii × E. grandis and E. pellita had the highest formation of shoots and the girdling vegetative rescue method had the best results in terms of generated shoots. E. saligna had better results regarding the variables related to the rooting of cuttings. The substrate S3 and the use of 1 500 mg L−1 of IBA provided the highest survival rate and better variables related to the rooting of the cuttings.