Browsing by Author "Alzamora, Rosa M."

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    Life cycle analysis to estimate CO2e emissions from forest harvesting systems in intensively managed Pinus radiata plantations
    (2022) Alzamora, Rosa M.; Oviedo, Waldo; Rubilar, Rafael
    A Life Cycle Analyses (LCA) assessment was evaluated comparing three harvesting systems on intensively managed Pinus radiata (radiata pine) plantations growing in the Biobio Region, Chile. Evaluated systems considered semi-mechanized, mechanized, and tower logging in steep slope forest operations. Our LCA study focused on CO(2)e emissions from six harvesting activities: felling, logging, processing, sorting, loading, and transportation, all under the ISO 14040 and ISO 14044 standards. The average and maximum monthly production scenarios were the highest for the semi-mechanized system with 24 and 25.2 kg CO(2)e m(-3), followed by the tower logging with 23.2 and 24.5 kg CO(2)e m(-3) and, lastly, the mechanized system with 11 and 12.1 kg CO(2)e m(-3). Similar to other studies, harvesting phases that contributed the most were logging, loading and transport. Concerning LCA stages, forest equipment operation generated the highest CO(2)e level across the three harvesting systems where fuel consumption was the activity that contributed with 76% of CO(2)e for the mechanized system, and 50% in the case of the tower logging and semi-mechanized systems. The mechanized system had the highest fuel use efficiency and the lowest CO(2)e emissions.
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    MODELLING THE INFLUENCE OF RADIATA PINE LOG VARIABLES ON STRUCTURAL LUMBER PRODUCTION
    (2023) Gavilan, Elvis; Alzamora, Rosa M.; Apiolaza, Luis A.; Saez, Katia; Elissetche, Juan Pedro; Pinto, Antonio
    We run logit models to explain the variability of Pinus radiata structural lumber in 71 second and third un-pruned logs. The response variable was the proportion of lumber with a static modulus of elasticity greater or equal than 8000 MPa, pMSG8+, and the explanatory variables were log volume, branch index, largest branch, log internode index, wood basic density, and acoustic velocity. The average pMSG8+ volume was 44,30 % and 36,18 % in the second and third log respectively. Ten models were selected based on meeting statistical assumptions, their goodness of fit, and the statistical significance of their parameters. The best models (R2 -adj. > 0,75) included acoustic velocity (AV) as explanatory variable, which explained 56,25 % of the variability of pMSG8+. Models without AV presented goodness of fit ranging from 0,60 to 0,75 (R2 -adj.), and variables with the highest weight to explain the variability ofpMSG8+ were volume, followed by wood basic density, branch index, and largest branch. It is possible to model pMSG8+ from log variables even when acoustic velocity is not available; however, this requires wood basic density models calibrated for the Pinus radiata growing zone.
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    Peeler core and slabwood fibre properties for Pinus radiata D.Don pulp production
    (2024) Elissetche, Juan Pedro; Apiolaza, Luis A.; Alzamora, Rosa M.; Soto, Luis O.; Lasserre, Jean Pierre
    Background: Pulp production based on Pinus radiata D.Don is constantly improving the value recovery of logs. One example is using the peeler cores and slabwood derived from sawing and peeling processes to produce pulp. However, these two raw materials have not been characterised for their fibre properties. Methods: We report on four wood fibre quality attributes derived from peeler cores and slabwood, directly influencing pulp quality and pulping process: fibre length (mm), fibre width (gm), fines content (%), and coarseness (gg/m). This pilot study sampled two P. radiata stands grown on different sites and early silvicultural regimes in the Araucania Region of Chile. Analysis of wood fibre consisted of three trees per stand, and six discs per tree: two at the bottom, two at breast height (1.3 m), and the last two at 5.23 m height. Results: The trajectory of mean annual increment in diameter at breast height (MAI) and periodic annual increment in diameter at breast height (PAI) for trees in the two stands aligned with their respective site qualities and silvicultural regimes. In Stand 1, with a site index of 36, and Stand 2, with a site index of 31, the average proportions of juvenile wood (measured at 1.3 m) were 50% and 53%, respectively. Thus, despite weed control and fertiliser application in Stand 1, there was no increase observed in the proportion of juvenile wood. There were significant differences in fibre properties between peeler core and slabwood, and these differences were present across the range of tree heights and diameters (p<0.05). While there were no statistically significant differences among disc positions, significant distinctions emerged between stands and wood types. The interaction between these factors was also found to be statistically significant (p<0.05). Conclusions: Our study suggests that adding these two materials into the mix for producing pulp would have positive implications due to pulp from peeler core is more suitable for printing and writing grades and addition of mature wood from slabwood, could improve strength properties of paper manufacture. However, it is necessary to test the optimal proportion for the final mix.
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    Wood Basic Density Assessment of Eucalyptus Genotypes Growing under Contrasting Water Availability Conditions
    (2024) Elissetche, Juan Pedro; Alzamora, Rosa M.; Espinoza, Yosselin; Emhart, Veronica; Pincheira, Matias; Medina, Alex; Rubilar, Rafael
    Limited research exists on wood properties in E. nitens x E. globulus hybrid genotypes grown in water-limited conditions generated by the climate change influence in Mediterranean areas. The EUCAHYDRO project aimed to assess environmental stress impacts on eucalyptus genotypes, including responses to reduced water availability, and to evaluate wood density and resistance using the non-destructive drill resistance technique. This study focused on 10-year-old E. nitens x E. globulus hybrids and Eucalyptus badjensis Beuzev. & Welch, revealing that low irrigation led to a 13% (p < 0.05) decrease in diameter and a 6.5% (p > 0.05) increase in wood density for the hybrids. On the contrary, E. badjensis demonstrated a noteworthy 22% increase in wood density (p < 0.05), while showing a corresponding 0.6% growth increase (p > 0.05), as measured by the diameter at breast height. Drill resistance measurement results indicated that E. nitens x E. globulus' amplitude ranged from 20.1% to 26.6%, while E. badjensis' ranged from 20.8% to 27.2%. The study revealed a high correlation between resistance amplitude and wood density, with coefficients of 0.97 observed for E. nitens x E. globulus and 0.84 for E. badjensis (p < 0.05). These findings fall within the range reported in similar studies involving Eucalyptus spp. The primary focus of the research was to assess the growth potential and wood quality of novel Eucalyptus spp. under conditions of water limitation. The study also explored the utility of drill resistance as a predictive measure for evaluating wood density as an indicator of wood quality.