Browsing by Author "Paulina Fernandez, M."

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    A functional-structural model for radiata pine (Pinus radiata) focusing on tree architecture and wood quality
    (OXFORD UNIV PRESS, 2011) Paulina Fernandez, M.; Norero, Aldo; Vera, Jorge R.; Perez, Eduardo
    Backgrounds and Aims Functional-structural models are interesting tools to relate environmental and management conditions with forest growth. Their three-dimensional images can reveal important characteristics of wood used for industrial products. Like virtual laboratories, they can be used to evaluate relationships among species, sites and management, and to support silvicultural design and decision processes. Our aim was to develop a functional-structural model for radiata pine (Pinus radiata) given its economic importance in many countries.
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    A portable method to estimate wood basic density from increment cores using spectroscopic techniques
    (SAGE PUBLICATIONS LTD, 2010) Galleguillos Hart, Cristobal; Paulina Fernandez, M.; Guesalaga, Andres
    The aim of this paper is to report the use of spectroscopic techniques for the measurement of basic wood density in Eucalyptus nitens, using samples in a state similar to that found in the field; so the current design can later be extended to a portable instrument that could eventually estimate the wood characteristics of a standing tree. Model calibration was carried out using wet samples taken from eight-year-old trees. Each sample was scanned to acquire two types of spectra: Raman and near infrared (NIR). Several pre-processing techniques were applied to the spectra in order to obtain the best possible prediction models for wood basic density using partial least squares (PLS) regression. The model selection criteria were based on maximising the coefficients of determination R-c(2) and r(v)(2) and minimising the root mean square error (RMSE). The potential of NIR for this purpose was demonstrated; r(v)(2) up to 0.87 and RMSEP down to 8.6 kg m(-3) were obtained. Raman spectroscopy proved to be unfit for the application, yielding extremely low correlation values and models with low predictive capabilities.
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    Is the first flowering event and corresponding maturity phase in trees related to radial wood density changes?
    (2016) Paulina Fernandez, M.; Cornejo, Barbara
    Although first flowering in trees causes clear changes in main stem morphological trends, we prove that it does not totally explain changes in wood density trends.
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    Using Tree Height, Crown Area and Stand-Level Parameters to Estimate Tree Diameter, Volume, and Biomass of Pinus radiata, Eucalyptus globulus and Eucalyptus nitens
    (2022) Gonzalez-Benecke, Carlos A.; Paulina Fernandez, M.; Gayoso, Jorge; Pincheira, Matias; Wightman, Maxwell G.
    Accurate estimates of tree diameter, height, volume, and biomass are important for numerous economic and ecological applications. In this study, we report exponential equations to predict tree DBH (cm), stem volume over bark (VOB, m(3)), and total above-stump biomass (TASB, kg) using three varying levels of input data for Pinus radiata D. Don, Eucalyptus globulus Labill., and Eucalyptus nitens (H.Deane & Maiden) Maiden planted trees. The three sets of input data included: (1) tree height (HT, m), (2) tree HT and ground projected living crown area (CA, m(2)), and (3) tree HT, CA, and additional stand parameters. The analysis was performed using a large dataset covering the range of distribution of the species in central Chile and included stands of varying ages and planting densities. The first set of equations using only HT were satisfactory with Adj-R-2 values ranging from 0.78 to 0.98 across all species and variables. For all three species, estimation of DBH, VOB, and TASB as a function of HT improved when CA was added as an additional independent variable, increasing Adj-R-2 and reducing RMSE. The inclusion of stand variables, such as age and stand density, also resulted in further improvement in model performance. The models reported in this study are a robust alternative for DBH, VOB, and TASB estimations on planted stands across a wide range of ages and densities, when height and CA are known, especially when input data are derived from remote sensing techniques.