Search Results (46)

The Brazilian forestry sector comprises 9.94 million hectares of plantations, with eucalyptus dominating 75% of this area for pulp production. Technological advances have enhanced machinery performance, with the cut-to-length system being the primary method for pulpwood production. This study aimed to optimize the operational cycle of the log loader by evaluating productivity, operational cycles, and loading costs. Data were collected in Bahia, northeastern Brazil, from a forestry company operating under varying productivity scenarios and forest rotations. Time and motion studies were conducted to assess the log loader’s cycles, while productivity and cost analyses were performed. The results indicated that predictive models effectively explained productivity variations. The log loader’s productivity increased with the average volume per tree (AVT) and decreased with the number of movements, which consumed 68% of the cycle time due to wood adjustment and stack organization. Stages such as personal breaks, truck movements, crane adjustments, and cleaning of fallen material showed no significant statistical differences. Loading costs rose by up to 154% with increased movements and decreased with a higher AVT. Additionally, loading tri-train trucks significantly influenced transportation efficiency, emphasizing the importance of optimizing the log loader’s cycle to balance costs and enhance transportation operations. Full article

Eucalyptus cultivation in Brazil benefits from techniques such as mini cutting; however, adverse climatic conditions in the southern region of the country limit seedling production. This study evaluated the effects of LED lighting (blue, red, combined, and natural) and cultivation environments (greenhouse with and without heating, and conventional nursery) on the propagation of Eucalyptus dunnii. The experiment, conducted in Otacílio Costa, SC, followed a two-factor (4 × 4) design with biweekly data collection from March to September 2024. Variables analyzed included sprout productivity, rooting performance, phytosanitary status (powdery mildew incidence), physiological parameters (photosynthetic rate, stomatal conductance, transpiration), and nutritional content. The results showed that LED lighting and cultivation environments did not affect the incidence of powdery mildew. Rooting was enhanced during winter in the heated mini-tunnel system. Sprout productivity was highest in the mini tunnel (~360 sprouts/m² under red light in winter), while heated environments led to a reduction in sprout production. Physiological variables such as photosynthetic rate and stomatal conductance were improved in the heated mini-tunnel, and transpiration responded to the interaction between light spectrum and environment. The evaluated factors did not cause significant changes in the nutritional profile of the mini stumps. It is concluded that the mini tunnel, particularly when heated during winter, enhances rooting and physiological responses, while red LED light increases sprout productivity. Supplemental LED lighting proved to be a strategic tool for overcoming seasonal limitations in Eucalyptus propagation. Full article

Urban forests are crucial for biodiversity and climate resilience. This study investigated the impact of human disturbances on carbon (C) stocks in un-conserved forests of Entoto Mountain, Addis Ababa, Ethiopia, focusing on forest structure: important value index (IVI), species diversity (H’), regeneration pattern status, and C storage in aboveground biomass (AGB), belowground biomass (BGB), litter biomass (LB), and soil. Field data were collected from 35 quadrats across two altitudes, and human disturbances were observed, including firewood collection, tree cutting, soil excavation, and road and infrastructure inside the sample plot. Results indicate low species diversity dominated by Eucalyptus globulus Labill and Juniperus procera Hoechst. Ex Endl., with fair regeneration. Higher altitudes showed greater measured C stock (572.62 tC ha⁻¹) than lower altitudes (495.03 tC ha⁻¹), attributed to larger trees. C values in the upper altitude for AGB, BGB, LB, and soil (0–30 cm) were higher than at lower altitudes. The IVI showed a significant positive correlation with C in aboveground biomass, C in belowground biomass, and total C stock, whereas H’ also showed a significant (p < 0.05) positive correlation with the total number of trees. It is concluded that forest structures contribute to the C stock of this area. Given the importance of the un-conserved Entoto Mountain forest, it is recommended to prioritize the conservation of old-growth forest species in the area, as they demonstrate the highest capacity for C accumulation. Full article

Eucalyptus cloeziana is an important, fast-growing, precious timber species in southern China, with tissue culture being the primary method for its propagation. However, the declining proliferation coefficient of adventitious shoots with multi-generation culture is a major constraint on its rapid propagation. This study aims to address this issue through the selection of suitable explants and optimizing the plant growth regulators’ formulation during the process of shoot proliferation. In this study, we cut shoots from the 21st generation of the tissue-cultured seedlings of ‘Chuanlinzhen 7523’ into apical, middle, and basal sections, and we measured their content of endogenous hormones. The proliferation coefficient (PC) and growth coefficient (GC) of explants under different concentrations of plant growth regulators were analyzed and ranked using the PCA method. The results indicated that the shoot basal sections were the best for proliferation when treated with 0.40 mg/L BAP (6-benzylaminopurine), 0.20 mg/L NAA (naphthaleneacetic acid), and 0.20 mg/L TDZ (thidiazuron), yielding a PC of 4.7 and a GC of 4.1. These basal sections ranked first with a rooting rate of up to 80%. When the rooted plantlets were acclimatized in the nursery, a survival rate of 100% was achieved. This protocol—from proliferation to acclimation—effectively improves the propagation efficiency of E. cloeziana ‘Chuanlinzhen 7523’ after multi-generation propagation. Full article

This research evaluates the feasibility of using eucalyptus oil blended with conventional diesel fuel in diesel engines. Eucalyptus globulus is one of the main tree species cultivated for paper pulp in western European countries such as Portugal, and eucalyptus oil is one of the byproducts that so far has not been sufficiently evaluated as a biofuel. This study assesses the impact of using this additive on engine performance parameters and emissions as a means to contribute to reducing fossil fuel consumption and pollutant and greenhouse gas (GHG) emissions. The analysis revealed that the addition of eucalyptus oil had a positive effect on torque, a critical performance parameter, with biofuel blends showing consistent torque increases at lower engine speeds. However, torque tended to decrease towards the higher range of engine speed for eucalyptus oil–diesel blends. Several blends showed lower brake specific fuel consumption compared to regular diesel at high engine loads and low engine speeds. Brake thermal efficiency did not vary substantially at lower engine speeds and loads but decreased at higher speeds and loads. Pollutant emissions, particularly unburned hydrocarbons and nitrogen oxides, were influenced by fuel composition, with biofuel blends showing both increases and decreases compared to diesel. It is noteworthy that eucalyptus oil blends exhibited up to a 60% reduction in smoke opacity under specific operating conditions at low speed and high load for 10% incorporation (10EU90D), suggesting that in addition to the already positive effects of cutting down fossil CO₂ emissions in proportion to the substitution of fossil diesel with nearly carbon-neutral eucalyptus oil, more environmental benefits may be expected from the incorporation of this product. Although the present economic viability of using eucalyptus oil as a biofuel is still not guaranteed, the present study seems to reinforce its technical viability. Future prospects for the improvement of oil yield through biotechnology, the economic interest of this product for several countries, and the updating and upscaling industrial processes may allow the viability of this biofuel to remain a possibility in the future Full article

Due to the continuous optimization of cutting plans, the cotton scrap size resulting from the cutting of components for clothing production (post-industrial residues) is often considered insufficient to obtain fibres with the proper length to produce a new yarn through mechanical recycling processes; so it is important to search for other applications for these wastes. In this context, small pieces of cotton were submitted to a shredding process to obtain recycled fibres. Cotton small pieces and recycled fibres were then submitted to a refining process to achieve refined fibres. Using these materials alone and in blends with refined and unrefined bleached eucalyptus kraft pulp (BEKP), wet-laid nonwovens were developed and characterized. An analysis of the results revealed that the replacement of unrefined BEKP by 70% cotton waste fibres in wet-laid nonwovens, reducing the use of virgin raw material, enhances the structures’ mechanical properties by 80% and 14%, for small pieces or recycled fibres, respectively. Additionally, refining small pieces of cotton seems to be more promising than refining recycled fibres, because less steps are required to obtain wet-laid nonwovens with better mechanical properties. These results highlight the potential of this approach to be explored further for different products and end applications. Full article

The aim of this research was to determine the most productive tree-cutting methods, and the factors influencing them, in flat and sloping terrains in tree plantations in Brazil. The study utilized drone-captured video material from harvesting operations in eucalyptus and pine plantations. In both terrains, two cutting methods were compared, differing in the felling to the side method used: either at the edge or inside of the harvesting front. In addition, on flat terrain, the efficiency of forward felling was studied in relation to the aforementioned cutting methods. In sloping terrain, the machines were also equipped with a winch assistance system. The time study data of the harvesting work were processed using a video analysis tool developed for the research. The output data of the cut trees were collected with the automatic measuring system of the harvester. Statistical tests were used to determine the most productive cutting methods by analyzing differences in productivity. With an average tree size of 0.3 m³, cutting productivity was 45 m³/E₀h in pine cuttings and 55 m³/E₀h in eucalyptus cuttings. The average cutting productivity on flat terrain was about 11 m³/E₀h higher than on sloping terrain, mainly due to the time spent attaching the winch assistance system, which was a necessary phase of the work on sloping terrain. The research results suggest that it would be most productive to use sideways felling inside the harvesting front method. However, the need for further research is evident, if we want to precisely identify the factors and work phases in the tree-cutting cycle affecting differences in the productivity of the harvesting chain in tree plantations. Full article

The yield of Eucalyptus regnans logs for lumber production was evaluated. Crack width and length at each log end were measured. Two log-cutting plans were used to obtain sawn lumber. The first plan (PA) considered logs with diameters varying from 28 to 40 cm, and in the second plan (PB), the log diameters ranged from 42 to 56 cm (PB). Lumber yield was determined using two log volume methods: the Japanese Agricultural Standards (JAS) and Smalian’s equation. The deformations of E. regnans lumber were measured. The Australian and Chilean standards were used to classify sawn lumber. The results showed that logs had radial cracks at both log ends. Cracks were classified into two groups, considering the crack length. Regarding the lumber deformations, most boards exhibited level B bows and crooks in both cutting plans. Levels A and B twists were prevalent in PA, whereas in PB, level A significantly outnumbered level B. The lumber yield of E. regnans in PB was higher than in PA. The lumber yield determined by Smalian’s equation was higher than that determined by the JAS method. This research provides insight into the characterization of E. regnans for lumber production, highlighting its relevance in the forestry industry. Full article

The total loss lubrication system that is typical of chainsaws is responsible for a massive dispersion in the agro-forestry environment of highly impactful pollutants, mostly of fossil origin, often well known as carcinogenic substances, which, in addition to presenting a risk to the environment, represent an important risk factor for human health, especially for chainsaw users. During its use, the chain lubricant is dispersed from the guide bar tip in the form of droplets and aerosol, or it is adsorbed on wood residues and sawdust. Then, it is subjected to drift, settles on the ground and vegetation, and can hit the operators, who, after prolonged exposures, can suffer both irritation of the respiratory tract and dermal absorption. Such a risk factor is often amplified by the widespread use of less-expensive, sometimes illegal alternatives, such as exhausted motor oils. To mitigate said negative effects, a process has been in progress for several years that is aimed at replacing conventional lubricants with synthetic or biobased oils with increasing biodegradability. As a contribution to this process, a study has been started on the possibility of using refined olive pomace oil (ROPO) as a base stock for the formulation of a totally biodegradable chainsaw lubricant. On purpose, to improve its properties of viscosity and adhesivity, such an oil was added with a biodegradable thickening agent, obtaining four formulations with different viscosity. After a lab test and a preliminary cutting test on firewood, the formulation with 2% of thickener resulted in being the best, and 3.0 g kg⁻¹ of tert-butylhydroquinone (TBHQ), a food-grade antioxidant, was then added to form the final formulation (F₂) to be compared, in the subsequent four test sessions, to a biodegradable commercial chain lubricant (S_B). The tests were carried out without changing the chainsaw setting, on different wood species, both in forest and, with the aim of increasing the repeatability of tests conditions and comparability of results, at a fixed point. The fluids’ performances were mainly evaluated based both on the operators’ opinions and on the measurements of the chain–bar temperatures and of saw chain wear related to a predefined number of cuts. As to the destiny of the fluid dispersed during cutting, the overall dispersion was assessed by considering the average working time, the consumption of chain lubricant, and the forest area cut down daily. Eventually, the amounts of inhalable and respirable dust particles as vectors of oil residues were quantified by means of personal air samplers worn by the operators and analyzed to determine any differences in the concentration of metallic elements. The test results evidenced chain temperatures that were 0.5, 4.9, and 12.5 °C higher with F₂ relating to S_B, respectively, in the cutting of trunks of fresh Pinus, Eucalyptus, and dry Pinus. They were accompanied by chain weight losses of 89.5% and 35% higher with F₂ relating to S_B, respectively, in cutting tests of Turkey oak and Poplar. Such a greater wear, however, apparently did not affect the saw chain’s cutting efficiency with F₂, since the operators declared that they did not notice any difference between the performances of the two fluids at the time of comparison. The effects of higher wear on the chain lifetime, any deriving risks for the operator’s safety, and the possibility to reduce the wear levels observed with F₂ will be explored in a further study, e.g., through different settings of the lubricating system of the chainsaw. The results of the analyses of the air-sampled dust residues that were evidenced with F₂ showed lower concentrations of respirable and inhalable particles and of some metallic elements (Al, Mg, and Ca) than those with S_B. This behavior probably depends on the different interaction between sawdust and the two fluids, which differ according to their chemical–physical characteristics (different viscosity, composition, and additives). However, it represents a positive factor in favor of the use of the ROPO-based lubricant, emphasized by the total biodegradability of its residues that are possibly contained in the dust inhaled by the operators. Full article

Eucalyptus plantation forests in southern China provide not only the economic value of producing timber, but also the ecological value service of absorbing carbon dioxide and releasing oxygen. Based on the theory of spatial colonial modeling, this paper proposes a new method for 3D reconstruction of tree terrestrial LiDAR point clouds for determining the aboveground carbon stock of eucalyptus monocotyledons, which consists of the main steps of tree branch and trunk separation, skeleton extraction and optimization, 3D reconstruction, and carbon stock calculation. The main trunk and branches of the tree point clouds are separated using a layer-by-layer judgment and clustering method, which avoids errors in judgment caused by sagging branches. By optimizing and adjusting the skeleton to remove small redundant branches, the near-parallel branches belonging to the same tree branch are fused. The missing parts of the skeleton point clouds were complemented using the cardinal curve interpolation algorithm, and finally a real 3D structural model was generated based on the complemented and smoothed tree skeleton expansion. The bidirectional Hausdoff distance, average Hausdoff distance, and F distance were used as evaluation indexes, which were reduced by 0.7453 m, 0.0028 m, and 0.0011 m, respectively, and the improved spatial colonization algorithm enhanced the accuracy of the reconstructed tree 3D structural model. To verify the accuracy of our method to determine the carbon stock and its related parameters, we cut down 41 eucalyptus trees and destructively sampled the measurement data as reference values. The R² of the linear fit between the reconstructed single-tree aboveground carbon stock estimates and the reference values was 0.96 with a CV(RMSE) of 16.23%, the R² of the linear fit between the trunk volume estimates and the reference values was 0.94 with a CV(RMSE) of 19.00%, and the R² of the linear fit between the branch volume estimates and the reference values was 0.95 with a CV(RMSE) of 38.84%. In this paper, a new method for reconstructing eucalyptus carbon stocks based on TLS point clouds is proposed, which can provide decision support for forest management and administration, forest carbon sink trading, and emission reduction policy formulation. Full article

Clonal plantation involves the rooting of cuttings from superior genotypes selected for their hybrid vigor and desired qualities. However, the cuttings of some Eucalyptus species and their hybrid genotypes present difficulties in their rooting capacity. Applying PGPR to cutting growth medium as a root stimulating agent has not been extensively studied for Eucalyptus tree species. We aimed to assess the rooting capacity of cuttings taken from two poor-rooting Eucalyptus hybrid clones of E. grandis × E. nitens through the application of PGPR in nursery trials. Seven rhizospheric bacterial species that demonstrated the ability to produce indole-3-acetic acid and to solubilise phosphate were used to prepare two rhizospheric consortium inoculums in which Pseudomonas-Bacillus strains and non-Pseudomonas-Bacillus were grouped. Inoculums were tested for their rooting stimulating capacity on cuttings of the hybrids GN 018B and GN 010 and compared to the nursery standard indole-3-butyric acid. A total of 320 cuttings were treated. Both hybrid clones demonstrated significant (p < 0.0001) genotype differences for all three growth responses, i.e., total, root, and shoot length. Cuttings of both hybrids demonstrated high survival rates and rooting percentage. Although several rooting architectural configurations were prevalent, the Pseudomonas-Bacillus consortium promoted adventitious root development and fibrosity in GN 018B hybrids. Full article

The genus Eucalyptus is a globally captivated source of hardwood and is well known for its medicinal uses. The hybrid and wild species of Eucalyptus are widely used as exotic plantations due to their renowned potential of adapting to various systems and sites, and rapid large-scale propagation of genetically similar plantlets, which further leads to the extensive propagation of this species. Tissue culture plays a crucial role in the preservation, propagation, and genetic improvement of Eucalyptus species. Despite unquestionable progression in biotechnological and tissue culture approaches, the productivity of plantations is still limited, often due to the low efficiency of clonal propagation from cuttings. The obtained F1 hybrids yield high biomass and high-quality low-cost raw material for large-scale production; however, the development of hybrid, clonal multiplication, proliferation, and post-developmental studies are still major concerns. This riveting review describes the problems concerning the in vitro and clonal propagation of Eucalyptus plantation and recent advances in biotechnological and tissue culture practices for massive and rapid micropropagation of Eucalyptus, and it highlights the Eucalyptus germplasm preservation techniques. Full article

Machine learning (ML) algorithms can be used to predict wood volume in a faster and more accurate way, providing reliable answers in forest inventories. The objective of this work was to evaluate the performance of different ML techniques to predict the volume of eucalyptus wood, using diameter at breast height (DBH) and total height (Ht) as input variables, obtained by measuring DBH and Ht of 72 trees of six eucalyptus species (Eucalyptus camaldulensis, E. uroplylla, E. saligna, E. grandis, E. urograndis, and Corymbria citriodora). The trees were cut down in two different epochs, rendering 48 samples at 24 months and 24 samples at 48 months, and the volume of each tree was measured using the Smailian method. This research explores five machine learning models, namely artificial neural networks (ANN), K-nearest neighbor (KNN), multiple linear regression (LR), random forest (RF) and support vector machine (SVM), to estimate the volume of eucalyptus wood using DBH and Ht. Artificial neural networks achieved higher correlations between observed and estimated wood volume values. However, the RF outperformed all models by providing lower MAE and higher correlations between observed and estimated wood volume values. Therefore, RF is the most accurate for predicting wood volume in eucalyptus species. Full article

Tree residue removal from Eucalyptus plantations after timber harvest can reduce soil functioning by reducing the organic matter input. To assess the effects of residue management systems (RMS) on soil aggregation, carbon (C) and nitrogen (N) content, and biological activities, a field trial was conducted in a commercial Eucalyptus plantation (loamy sand soil) in Mato Grosso do Sul, Brazil. The study assessed three RMS: cut-to-length (CTL), tree-length (TL), and bare litter (BL), respectively. After 21 months, undisturbed soil samples were collected and physically isolated into three aggregate-size fractions: large macroaggregates (LM), medium macroaggregates (SM), and microaggregates (MI). Results showed that these soils are mostly composed of LM (54%), and that removing harvest residues from the growing site included total organic carbon (TOC) by 28%, microbial biomass-C by 20%, fluorescein diacetate hydrolysis by 17%, and β-glucosidase activity by 26%, when compared to CTL. TL outperformed CTL for the proportion of LM and LM-associated TOC. Across fractions, a higher microbial quotient was observed in SM and MI fractions, suggesting that the TOC has higher stability inside the LM. This study suggests that leaving harvest residues on the soil should be recommended for Eucalyptus plantations, especially in low-fertility sandy soils, as it helps in maintaining the soil structure and biological activities critical for soil health and ecosystem function. Full article

With the growing demand for investment projects in renewable energy, it is essential for the economic feasibility analysis to consider the inherent uncertainties of these projects and enable more accurate investment decisions. In this way, we analyze whether investment projects in photovoltaic panels to produce electrical energy in a forest nursery are economically viable through the analysis of real options. We consider the energy demand of a forest nursery with an initial investment of USD 90,417 in photovoltaic panels. The managerial flexibilities of deferral, expansion of 30.0% of the energy production capacity, and the project’s abandonment were inserted into the binomial model of the decision tree, built in discrete time. The project’s expanded net present value was 79.2% higher than the traditional net present value, capturing the value of flexibilities for managers. The deferral option was the one that most impacted the expanded net present value. Investment projects in photovoltaic panels to produce electricity in a forest nursery are economically viable when analyzed through real options. Full article