Eucalyptus Benthamii Research Articles

Marker-based pedigree reconstruction reveals limited diversity within commercial Eucalyptus benthamii breeding populations in Brazil

Marker-based pedigree reconstruction reveals limited diversity within commercial Eucalyptus benthamii breeding populations in Brazil

Impacts of the Integrated Management of Invasive Weeds and Litter on Slope Hydrology in Eucalyptus Plantations in Central Yunnan, Southwest China

Background: The hydrological effects of invasive plant control in forestland have not been well studied in the past, and numerous scientific mysteries remain unsolved. The long-term suspension of the unsolved issues will unavoidably influence the sound growth and sustainable management of forest ecosystems. This study investigates the hydrological effects of controlling invasive weeds in forestland. The research aims to understand the impact of invasive weed control on soil and water loss. Methods: Conducted in Eucalyptus benthamii Maiden & Cambage plantations in Central Yunnan, SW China, which are invaded by alien weed Ageratina adenophora (Spreng.) R. M. King & H. Rob., four surface cover treatments were applied to study runoff and sediment yielding properties. The four surface cover treatments were weed harvesting and litter elimination (WH&LE), weed harvesting and litter retention (WH&LR), litter burning and weed renewal (LB&WR), and weed retention and litter retention (WR&LR). Essentially, WH&LE and LB&WR served as integrated management approaches for invasive weeds and litter, WH&LR was an independent weed control measure, and WR&LR served as a research control. Results: Runoff was significantly higher in the LB&WR plots (3.03 mm) compared to the WR&LR plots (1.48 mm) (p < 0.05). The WH&LE plots had higher runoff (2.39 mm) than the WR&LR plots (not statistically significant), while the WH&LR plots had less runoff (1.08 mm) than the WR&LR plots (not significant). Sediment yield was lower in the WH&LR plots (0.50 t/km2) than in the WR&LR plots (0.52 t/km2) (not significant), but significantly higher in the WH&LE plots (2.10 t/km2) and LB&WR plots (1.57 t/km2) than in the WR&LR plots (p < 0.05). Conclusions: Managing invasive weeds independently reduces the risk of soil and water loss, but combined management with litter can exacerbate the issue. Invasive weed control and litter management should be performed separately in slope plantations. This study provides a scientific basis for soil and water conservation, restoration and rehabilitation of plantation ecosystems.

Validation of the Physical and Mechanical Properties of Eucalyptus benthamii Maiden & Cambage Wood and Cross Laminated Timber Panels Using the Finite Element Method

Cross Laminated Timber (CLT) is a structurally complex panel that poses challenges in analysis due to the anisotropic nature of wood and the orthotropic characteristics of the composite. Numerical modeling using the Finite Element Method (FEM) offers a viable solution for analysis, particularly for addressing boundary value problems that are analytically challenging. Therefore, it is crucial to validate the experimental properties to ensure accurate results. The objective of this study was to validate the physical and mechanical properties for structural modeling using FEM, based on the characterization of Eucalyptus benthamii Maiden & Cambage wood and CLT panels. For wood characterization, the basic and apparent density were determined, and mechanical tests, including static bending, parallel-to-grain compression, and shear tests, were conducted. Utilizing the same batch of wood, three-layer CLT panels were manufactured and subjected to a non-destructive three-point bending test. This test was simulated in RFEM finite element software, employing Mindlin’s theory, and the displacements obtained were compared with the experimental method. The results from a Student’s t-test at a 5% significance level indicated no significant difference between the experimental and numerical methods, suggesting that the properties of the experimental E. benthamii CLT panel can be accurately represented by FEM.

Effects of Eucalyptus wood and leaf litter on saproxylic insects in the southeastern United States

Although Eucalyptus is widely planted outside its native range for timber and pulp production, the effects of these exotic plantations on biodiversity relative to native semi-natural forests or plantations of native tree species remain incompletely understood. Here, we compare the diversity of saproxylic beetles (Coleoptera) and true bugs (Hemiptera) between non-native Eucalyptus benthamii Maiden and Cambage (Camden white gum) and native Pinus taeda L. (loblolly pine) stands on the upper Coastal Plain of South Carolina, U.S.A. We sampled insects emerging from logs of both species placed in both stand types after 1, 2, 6, and 12 months in the field. Beetle and true bug richness and diversity were both significantly lower from eucalypt than from pine wood. Moreover, the two communities were compositionally distinct. Whereas pine supported many species of host-specific phloeoxylophagous beetles, most species collected from eucalypts were mycophagous or predatory taxa capable of utilizing a wide range of hosts. Species richness did not differ between logs placed in eucalypt vs. pine stands but Shannon’s diversity was significantly higher in the eucalypt stands, possibly due to greater sun exposure in the latter. Contrary to a previous study, we found no support for the idea that eucalypt litter reduces the diversity of saproxylic insects. Our findings add to the growing body of evidence that non-native plantations are less favorable to biodiversity than those consisting of native tree species.

Conservation, domestication and breeding of Eucalyptus benthamii, a threatened, cold-tolerant subtropical species with a restricted genetic base and lot of potential

Eucalyptus benthamii is a fast-growing eucalypt with excellent potential as a pulp and biomass crop in subtropical areas that are subject to occasional cold snaps. It is among the most frost-tolerant of fast-growing eucalypts and has been deployed commercially in selected regions of North and South America. Several relatively low-input domestication and breeding programs are underway. The species has a restricted natural range along the Nepean River system to the west of Sydney, Australia, and is facing ongoing threat due to fragmentation caused by agricultural developments, urban sprawl and dam construction. Two main subpopulations have been delineated (Nepean and Kedumba), with most of the world’s breeding populations predominantly based on a restricted sample of open-pollinated families from Kedumba. Two challenges are discussed. Firstly, conservation of the species is a high priority, made difficult in the less-sampled Nepean subpopulation by poor seed set, inbreeding and interspecific hybridization. Secondly, for ongoing genetic gain to be made, broadening the genetic base in breeding programs is a high priority. To tackle the first challenge, ex situ and circa situm conservation interventions are underway. Though technically challenging, this should eventually lead to more breeding material becoming available. International collaboration will be a key determinant of future success in meeting these challenges.

Performance of visible and Near-infrared spectroscopy to predict the energetic properties of wood

Wood can be used for fuel by direct burning, or as a raw material for other fuels; however, it is necessary to evaluate the energy properties to ensure the optimal use of this material. The most relevant characteristics to be analyzed are the higher heating value, volatile material content, fixed carbon content, and ash content. Along with the traditional methods, there are also non-destructive evaluations that are optimized for speed and reliability. Among these methods, visible spectroscopy and near-infrared spectroscopy have been proven to be robust for the prediction of several wood properties. The aim of this study was to evaluate the potential of visible spectroscopy and near-infrared spectroscopy for species discrimination and prediction of higher heating value, volatile material content, fixed carbon content, and ash content for Eucalyptus saligna, Eucalyptus dunnii, and Eucalyptus benthamii woods. For this purpose, multivariate principal component analysis and partial least squares regression were applied to the collected spectra. The principal component analysis satisfactorily discriminated the three species, explaining 99% of the variance of the visible spectroscopy spectra and 73% of that of the near-infrared spectra. The estimation of energetic properties through partial least squares regression was satisfactory for both visible spectroscopy and near-infrared spectroscopies, which presented calibration R² values close to 1 and low errors for all properties studied.

Correlations between dendrometric and allometric variables of Eucalyptus benthamii under agroforestry systems in the subtropic of Brazil

The growing interest in integrated agricultural production systems has increased the search for information about the arboreal component, thus, information about the correlations and associations between dendrometric and allometric variables are important. This study investigated the results obtained through simple correlation analysis and its breakdown via path analysis of dendrometric and allometric variables of Eucalyptus benthamii under different integrated systems and monoculture. The following variables were evaluated: diameter at 1.3 m above ground, total height, volume with and without bark, crown radius and biomass components stem wood and bark, branches, leaves and total aboveground biomass. Descriptive statistics showed the great variance of the data with coefficients of variation from 18 to 85.08%. All correlations (Spearman) between allometric and dendrometric variables were positive and 89% were statistically significant (p < 0.05). For the total aboveground biomass as dependent variable, the variables with the greatest direct effects were wood biomass (0.26), volume with bark (0.17) and branch biomass (0.15). With the results of the simple correlation any variable can be used in the modeling of the total aboveground biomass. However, the path analysis makes it clear that some variables have weak associations even with significant correlations of great magnitude.

Methane emissions and growth performance of beef cattle grazing multi-species swards in different pesticide-free integrated crop-livestock systems in southern Brazil

The aim of this study was to assess the growth performance, forage intake and methane (CH4) emissions by beef cattle grazing under different spatiotemporal integrated crop-livestock systems (ICLSs). The experiment was conducted for two years (2017–2018 and 2018–2019) in warm season perennial pastures and cool season annual pastures grazed by beef steers. Three pesticide-free ICLS treatments – livestock-forestry (LF); crop-livestock (CL), and crop-livestock-forestry (CLF) – plus, a livestock control pesticide-free system (L) were conducted in randomized complete block design, with three replicates per treatment. Maize crop rotation was done with cool season cover crop under no-tillage. Eucalyptus trees (Eucalyptus benthamii) were planted in 2013 and intercropped with tree alleys. The animal performance, organic matter (OM) intake and enteric CH4 emission, yield, and intensity were assessed. We found no significant difference (P > 0.05) for average daily gain (ADG), stocking rate (SR), and daily live weight gain (LWG) per area for the different ICLS arrangements and seasons. The ICLS arrangements did not affect (P > 0.05) CH4 emission, yield, and intensity, with averages of 186 g steer−1 day−1, 26 g kg−1 OM intake and 210 g kg−1 of ADG, respectively. The average CH4 emissions per steer per day, per OM intake, per ADG and LWG per area were greater (P < 0.05) for steers when grazing warm season compared to cool season pastures. The integration or not of beef cattle with crops and/or forestry does not influence CH4 emissions, yield, and intensity by beef steers grazing pastures under moderate grazing intensity. Our results reinforce that well-managed integrated systems are a reliable climate-smart agriculture alternative for increasing production, e.g., grain, wood, meat, and mitigating or without increasing greenhouse gas emissions, such as CH4 from enteric fermentation in beef cattle.

DETERMINATION OF E. benthamii PROPERTIES BY INFRARED SPECTROSCOPY AND PLS

Considering the interest in the Eucalyptus benthamii species and the search for alternatives to determine some physical properties in a fast and reliable way, the objective of this study was to build multivariate calibration models through the near infrared spectroscopy (NIR) technique and partial least squares regression (PLS) for wood basic density (BD) and chip moisture (U). Trees were sampled in five diametric classes and used to evaluate DB, as a function of 3 ages and 3 production regions of E. benthamii. We considered only plantations at 7 years of age in the harvest phase and chip samples considering pre-defined intervals of ten days, from the date of tree harvest to 90 days, in two seasons of the year (winter and spring) for moisture analysis. For DB and U, NIR models were calibrated and validated using partial least squares (PLS) regression. Calibration models were evaluated by correlation coefficients (R²), root mean square error (RMSE), and variance performance ratio (RPD). The models for near infrared (NIR) spectroscopy showed R² values ranging from 0.60 to 0.68 for basic density and 0.72 for moisture. The best model for DB observed was the one that considered only the DAP samples. It was concluded that the NIR technique was suitable for estimating the properties of moisture and wood density in this evaluated species, E. benthamii.

Uso de diodosemissores de luz (LEDs) no desenvolvimento e resposta a estresse hídrico em mudas de Eucalyptus benthamii (Myrtaceae)

ABSTRACT: Plants use light as a source of energy in the process of photosynthesis. Different levels of luminosity cause physiological and morphological changes in the plant, and its success depends on its adaptation to these different levels. Light emitting diodes (LED) have been proposed as a light source in controlled environments. The present research evaluated physiological and morphological aspects in Eucalyptus benthamii (Myrtaceae) seedlings kept under different colors of LED lamps and submitted to water stress. The experiment was carried out in a completely randomized design, in which the treatments were defined as: T1 (control, with white light); T2 (blue light); T3 (red light) and T4 (mixed blue and red light). Red light resulted in the best response to most morphological variables in plant growth. In response to water stress, blue light LEDs resulted in a better seedling response, with slower reduction of photosynthetic rate and other variables. This may indicate the possibility of reducing water deficit damage in seedlings acclimated to blue light prior to field planting.

Conservative or non-conservative strategy to advance breeding generation? A case study in Eucalyptus benthamii using spatial variation and competition model

Abstract The greatest challenge faced when breeding populations of forest species is to achieve the right equilibrium among genetic gain and no loss of the effective population size. Thus this study aims to define the best thinning strategy to compose a seed orchard of Eucalyptus benthamii to obtain genetic gain maintaining the effective population size. The population of E. benthamii studied consisted of 28 open-pollinated progenies. The diameter at breast height (DBH) and height (H) parameters were determined three years after planting. Measurement data were analyzed and compared using four different mathematical models (with and without competition effect and spatial variation). Strategies considering genetic gain and effective population size were simulated considering the number of families, the number of individuals between families, and the total number of individuals. The mathematical model accounting for the competition effect had the best fit for DBH whereas the model accounting for the environmental variation effect presented the best fit for H. The ranking of BLUPs grouped the families into three clusters (best, intermediate/average, worst/poor families). The strategy that maintains 40 % of the individuals, generates a genetic gain of 13 % in DBH and 8 % in total height while maintaining an effective population size greater than 92 for booth traits.

DENSIDADE BÁSICA DA MADEIRA, DIMENSÕES DAS FIBRAS E COMPOSIÇÃO QUÍMICA DA MADEIRA DE QUATRO ESPÉCIES DE Eucalyptus PLANTADAS NO SUL DO BRASIL

ABSTRACT In the Brazilian planted forest sector, most of the species used are from the genus Eucalyptus. Even though Southern Brazil has a suitable climate for species of the genus Pinus, the planting of frost-resistant Eucalyptus species has been increasing annually. The objective of this study was to evaluate the basic density, fiber dimensions, and chemical composition of Eucalyptus benthamii, Eucalyptus dunnii, Eucalyptus saligna, and Eucalyptus cloeziana woods. The trees used were from a six-year-old experimental plantation located in Canoinhas, state of Santa Catarina. For each species, three trees were selected, and discs were removed from each tree at 0%, 25%, 50%, 75%, and 100% of the commercial stem height. To evaluate the quality of the wood, the basic wood density, fiber dimensions, and chemical composition of the wood were determined by comparing the values between species and between the heights in the stem. The highest basic density was that of the wood of E. cloeziana; this species also had the greatest length and width of fibers. E. dunnii had the lowest levels of lignin and the highest levels of holocellulose. The highest lignin content was found in the wood of E. benthamii, E. saligna, and E. cloeziana. The relationship between wood properties and stem height was not relevant. The results highlight the tendency for higher extractives to be found at taller heights (100%), and holocellulose and lignin content are similar at all heights.

Using of relatedness and heritability in a Eucalyptus benthamii trial for conservation and breeding

Using of relatedness and heritability in a Eucalyptus benthamii trial for conservation and breeding

ESTIMATION OF THE MATING SYSTEM OF Eucalyptus benthamii Maiden at Cambage PROGENY

Eucalyptus benthamii is an important species used in monoclonal and hybrid forest plantations around the world. Few natural populations of the species remain, and as such it has been placed on the list of endangered species. We sampled 111 seeds of Eucalyptus benthamii from nine progenies across two provenances (Candói - two progenies; Vale do Corisco - seven progenies). Samples were genotyped using 19 microsatellite loci. A high number of alleles (from 80 to 114) were found in the studied progenies.

Growth and productivity of Eucalyptus benthamii in integrated crop–livestock systems in southern Brazil

Growth and productivity of Eucalyptus benthamii in integrated crop–livestock systems in southern Brazil

Photosynthetic light response curves in Eucalyptus benthamii and Eucalyptus dunnii clones

The photosynthetic light-response curve reflects the instantaneous response of the net photosynthetic rate to different gradients of photosynthetically active radiation. Genetic materials can respond differently to light and consequently alter productivity. Thus, this work aimed to compare clones of Eucalyptus benthamii and Eucalyptus dunnii by checking the CO2 assimilation rate due to the increase in photosynthetically active radiation. The evaluations were carried out in mini-stumps implanted in a clonal mini-garden system. The CO2 assimilation rate curves were determined with the aid of a portable photosynthesis meter. The curves of CO2 assimilation rate (A) in response to the increase in photosynthetically active radiation (PAR) were evaluated at values of 1500, 1000, 700, 450, 250, 120, 50 and 0 μmol m-2 s-1 for clones of E. benthamii and E. dunnii. The three Eucalyptus clones evaluated showed a similar behavior of the A/PAR curve, showing a high demand for photosynthetically active radiation. In general, the three clones were very similar in terms of CO2 assimilation rate due to the increase in photosynthetically active radiation

Harder, better, faster, stronger: Frost tolerance of Eucalyptus benthamii under cold acclimation

Eucalypts are the most planted hardwood trees worldwide because of their very rapid growth, exceptional wood quality and adaptability. However, most commercial species and derived hybrids are sensitive to frost, which remains as the largest obstacle to their introduction in warm/temperate climates. As evergreen species, Eucalypts have developed the ability to tolerate frost events based on physiological and molecular responses triggered by previous exposure to cold temperatures, globally named cold acclimation. To characterize the acclimation process in two species with different tolerance to frost, E. grandis (Eg) and E. benthamii (Eb), seedlings were exposed for different times to low temperatures. Frost tolerance was estimated in leaves by an electrolyte leakage assay, and metabolome and morpho-physiological changes studied and correlated to the observed acclimation responses. Eb showed higher basal frost tolerance and an earlier and stronger acclimation response to cold temperatures than in the frost sensitive Eg. Eb was able to modify several morpho-physiological parameters, with a restriction in plant height, leaf area and leaf fresh weight during acclimation. Metabolome characterization allowed us to differentiate species and strengthen our understanding of their acclimation response dynamics. Interestingly, Eb displayed an early phase of sugar accumulation followed by a rise of different metabolites with possible roles as osmolytes and antioxidants, that correlated to frost tolerance and may explain Eb higher capacity to acclimate. This novel approach has helped us to point to the main metabolic processes underlying the cold tolerance acquisition process in two relevant Eucalyptus species.

Genomic prediction of growth and wood quality traits in Eucalyptus benthamii using different genomic models and variable SNP genotyping density

Genomic prediction of growth and wood quality traits in Eucalyptus benthamii using different genomic models and variable SNP genotyping density

Influence of Eucalyptus spp. essential oils and tannins on herbivory

Eucalyptus (family Myrtaceae), a native plant from Australia, is a genus cultivated due to its oil, gum, pulp and timber used worldwide for different commercial applications. It is a plant with significant economic importance and possibly its cultivation, in Brazil and other countries, has reduced the exploitation of native trees. The secondary metabolism of Eucalyptus, as usually found in plants, produces essential oils and tannins, which may interfere in the consumption of plants by wild animals. The goal of the present work was to investigate the influence of essential oil and tannins concentration on the herbivory of seven Eucalyptus taxa. Essential oils composition for all species investigated were characterized by CG MS HS-Trap analysis. The lowest hebivory rate were associated to Urocam, Grancam and Eucalyptus benthamii. Those taxa were associated with the presence of mix oil compounds, α/β-Pinene, Pinocarveol, α-Terpineol and Tannins. Tannins concentrations and essential oil are an important factor that contributes to the plant protection against herbivory.

High-Density UAV-LiDAR in an Integrated Crop-Livestock-Forest System: Sampling Forest Inventory or Forest Inventory Based on Individual Tree Detection (ITD)

Lidar point clouds have been frequently used in forest inventories. The higher point density has provided better representation of trees in forest plantations. So we developed a new approach to fill this gap in the integrated crop-livestock-forest system, the sampling forest inventory, which uses the principles of individual tree detection applied under different plot arrangements. We use a UAV-lidar system (GatorEye) to scan an integrated crop-livestock-forest system with Eucalyptus benthamii seed forest plantations. On the high density UAV-lidar point cloud (&gt;1400 pts. m2), we perform a comparison of two forest inventory approaches: Sampling Forest Inventory (SFI) with circular (1380 m2 and 2300 m2) and linear (15 trees and 25 trees) plots and Individual Tree Detection (ITD). The parametric population values came from the approach with measurements taken in the field, called forest inventory (FI). Basal area and volume estimates were performed considering the field heights and the heights measured in the LiDAR point clouds. We performed a comparison of the variables number of trees, basal area, and volume per hectare. The variables by scenarios were submitted to analysis of variance to verify if the averages are considered different or equivalent. The RMSE (%) were calculated to explain the deviation between the measured volume (filed) and estimated volume (LiDAR) values of these variables. Additionally, we calculated rRMSE, Standard error, AIC, R2, Bias, and residual charts. The basal area values ranged from 7.40 m2 ha−1 (C1380) to 8.14 m2 ha−1 281 (C2300), about −5.9% less than the real value (8.65 m2 ha−1). The C2300 scenario was the only one whose confidence interval (CI) limits included the basal area real. For the total stand volume, the ITD scenario was the one that presented the closer values (689.29 m3) to the real total value (683.88 m3) with the real value positioned in the CI. Our findings indicate that for the stand conditions under study, the SFI approach (C2300) that considers an area of 2300 m2 is adequate to generate estimates at the same level as the ITD approach. Thus, our study should be able to assist in the selection of an optimal plot size to generate estimates with minimized errors and gain in processing time.