António J. A. Santos

Estimation of wood basic density of Acacia melanoxylon (R. Br.) by near infrared spectroscopy

Wood basic density is one of the most important wood quality properties and one of the simplest to assess but it is too time consuming to be really useful for the screening of populations or for improvement programmes where large numbers of samples need to be assessed. Although the usefulness of near infrared (NIR) spectroscopy to assess wood properties, including wood density, is well established only a few of the published models are suitable for screening. The NIR-based partial least squares regression models obtained in this study can be used for screening the basic density of the Portuguese blackwood [Acacia melanoxylon (R. Br.)] population with standard errors of cross-validation of only 11 kg m−3 and values for the residual prediction deviation well above the 2.5 limit. It was also concluded that at least 45 samples for calibration and a further 16 samples for validation are necessary to obtain acceptable models for screening. Even using a very small number of spectra per disc, accurate estimates of wood basic density were obtained.

Genetic variation of chemical and mechanical traits of maritime pine (Pinus pinaster Aiton). Correlations with wood density components

Abstract• BackgroundGenetic selection for one trait can have an impact on other important traits for final use; thus, it is important to assess the correlation between traits.• MethodsGenetic control and relationships among lignin content predicted by near infrared spectroscopy, radial modulus of elasticity (MOERad) and the radial modulus of rupture (MORRad), as well as its correlations with wood density components and spiral grain were assessed by estimating heritability, phenotypic and genetic correlations using 552 Pinus pinaster trees from 46 half-sib families.• ResultsThe results of this study showed that lignin amount is under a moderate genetic control (h2 = 0.34) but due to the low coefficient of variation observed, selection for lignin content through breeding could yield modest gains. Selection based on density will result in a decrease of the lignin content, and that the lignin content was more dependent on the proportion of latewood.• ConclusionsThe results show that MOERad and MORRad are under moderate genetic control (h2 = 0.34 and h2 = 0.30 respectively), suggesting possible genetic gains by selection for higher resistance and elasticity. MOERad had higher correlations with latewood than earlywood components. Negative correlations were observed between mechanical traits and lignin content, while the correlations with spiral grain were positive.

Fibre Morphological Characteristics of Kraft Pulps of Acacia melanoxylon Estimated by NIR-PLS-R Models

In this paper, the morphological properties of fiber length (weighted in length) and of fiber width of unbleached Kraft pulp of Acacia melanoxylon were determined using TECHPAP Morfi® equipment (Techpap SAS, Grenoble, France), and were used in the calibration development of Near Infrared (NIR) partial least squares regression (PLS-R) models based on the spectral data obtained for the wood. It is the first time that fiber length and width of pulp were predicted with NIR spectral data of the initial woodmeal, with high accuracy and precision, and with ratios of performance to deviation (RPD) fulfilling the requirements for screening in breeding programs. The selected models for fiber length and fiber width used the second derivative and first derivative + multiplicative scatter correction (2ndDer and 1stDer + MSC) pre-processed spectra, respectively, in the wavenumber ranges from 7506 to 5440 cm−1. The statistical parameters of cross-validation (RMSECV (root mean square error of cross-validation) of 0.009 mm and 0.39 μm) and validation (RMSEP (root mean square error of prediction) of 0.007 mm and 0.36 μm) with RPDTS (ratios of performance to deviation of test set) values of 3.9 and 3.3, respectively, confirmed that the models are robust and well qualified for prediction. This modeling approach shows a high potential to be used for tree breeding and improvement programs, providing a rapid screening for desired fiber morphological properties of pulp prediction.

Morphological, mechanical, and optical properties of cypress papers

Abstract The pulping properties of cypress species are not known and the present paper aims to filling this gap. Namely, Cupressus lusitanica Mill., C. sempervirens L. and C. arizonica Greene have been submitted to kraft pulping and the pulp properties are compared with those of Pinus pinaster Aiton. and P. sylvestris Watereri as references. Schopper Riegler degree, density, Bekk’s smoothness, tensile index, tear index, burst index, stretch, dry zero-span strength, wet zero-span strength, brightness, opacity and light scattering coefficient have been tested. The pulp yields and delignification degrees of cypress woods were lower than those of the pine references. Fibre length, width and coarseness were statistically different between pines and cypress species and C. sempervirens pulps have corresponding data close to those of pine species. Cypress pulps can be refined much faster than pine pulps. The papers sheets of cypress fibres have, in general, lower mechanical performance than those of pine fibres. Papers from C. arizonica and C. lusitanica are similar and C. sempervirens has intermediate properties being between the other cypress and pine species. However, cypress fibres are relatively short, flexible and collapsible and can be refined with low energy demand, and thus could be incorporated into papers resulting in products with better light scattering and smoothness.

Application of FTIR-ATR spectroscopy on the bee pollen characterization

Bee pollen contains almost all nutrients required by the human organism as well as diverse health-promoting substances. However, its composition and nutritional value greatly depend on the botanical origin. As such, it is important to develop a rapid and non-expensive methodology that allows studying its characteristics, making labelling more objective and easier. The FTIR-ATR technique was used to predict some nutritional parameters in 126 bee pollen samples. FTIR-ATR spectrum obtained in the region between 4000 and 400 cm−1 with PLS Regression models were used to correlate spectral information with the data obtained using reference methods. In this first approach with pollen samples, good correlation models with appropriate accuracy were obtained for the evaluated parameters with r2 varying from 74.8 to 97% and residual prediction deviation between 2.0 and 5.8. These results suggest that FTIR-ATR may be a useful technique for assessing bee pollen’s composition.