{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,11,18]],"date-time":"2025-11-18T10:20:10Z","timestamp":1763461210847,"version":"3.45.0"},"reference-count":29,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2025,11,18]],"date-time":"2025-11-18T00:00:00Z","timestamp":1763424000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"FCT\u2013Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia, I.P.","award":["UID\/00239\/2025","UID\/PRR\/00239\/2025"],"award-info":[{"award-number":["UID\/00239\/2025","UID\/PRR\/00239\/2025"]}]},{"name":"FCT Contract-program"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Forests"],"abstract":"<jats:p>The classification of cork planks as a raw material is traditionally performed through visual inspection of cork pores and defects, both in forest owners\u2019 associations and industrial settings. This method introduces subjectivity and limits reproducibility. This study aimed to develop near-infrared spectroscopy (NIRS) models for predicting porosity in raw cork, distinguishing virgin, secondary, and mature cork types. A total of 156 cork samples representing the three cork types were analyzed. Spectra were collected on the transverse and radial surfaces using a Bruker MPA spectrophotometer. Partial Least Squares Regression (PLS-R) models were developed separately for each cork type, yielding cross-validated coefficients of determination (R2) between 0.48 and 0.64. Additionally, two global models were obtained using a random data split (60% for cross-validation and 40% for validation), differentiated by whether or not areas corresponding to insect galleries were included. The model incorporating insect galleries achieved R2 values of 0.63 (cross-validation) and 0.46 (validation), while the model excluding them yielded R2 values of 0.51 and 0.52, respectively. The final optimized model, based on all samples and using selected spectral regions (9500\u20137500 and 6100\u20135450 cm\u22121) with first derivative and vector normalization preprocessing, achieved an R2 of 0.61, RMSECV of 0.025, and RPD of 1.6 using five latent variables. This model was used to estimate porosity coefficients in visually classified secondary and mature cork. Results confirmed an inverse relationship between porosity and cork quality class: higher-quality classes (Q1, Q2) had lower porosity, with Q1 being the most homogeneous. Porosity increased from Q2 to Q6 in mature cork, expressing declining quality. Greater variability in lower-quality classes highlights porosity\u2019s relevance for classification. These results demonstrate the potential of NIRS as a non-destructive tool for assessing cork porosity, offering a more objective and efficient alternative to conventional methods.<\/jats:p>","DOI":"10.3390\/f16111737","type":"journal-article","created":{"date-parts":[[2025,11,18]],"date-time":"2025-11-18T09:58:42Z","timestamp":1763459922000},"page":"1737","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Predicting Porosity in Raw Cork Using Near-Infrared Spectroscopy"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6626-4848","authenticated-orcid":false,"given":"Ana","family":"Alves","sequence":"first","affiliation":[{"name":"Centro de Estudos Florestais, Laborat\u00f3rio Associado TERRA, Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, 1349-017 Lisboa, Portugal"},{"name":"SERQ\u2014Innovation and Competence Forest Centre, 6100-711 Sert\u00e3, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1889-1721","authenticated-orcid":false,"given":"Joana Amaral","family":"Paulo","sequence":"additional","affiliation":[{"name":"Centro de Estudos Florestais, Laborat\u00f3rio Associado TERRA, Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, 1349-017 Lisboa, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5177-6878","authenticated-orcid":false,"given":"Diana I.","family":"Santos","sequence":"additional","affiliation":[{"name":"Centro de Estudos Florestais, Laborat\u00f3rio Associado TERRA, Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, 1349-017 Lisboa, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0019-0847","authenticated-orcid":false,"given":"Jos\u00e9","family":"Gra\u00e7a","sequence":"additional","affiliation":[{"name":"Centro de Estudos Florestais, Laborat\u00f3rio Associado TERRA, Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, 1349-017 Lisboa, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4279-6188","authenticated-orcid":false,"given":"Jos\u00e9","family":"Rodrigues","sequence":"additional","affiliation":[{"name":"Centro de Estudos Florestais, Laborat\u00f3rio Associado TERRA, Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, 1349-017 Lisboa, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2025,11,18]]},"reference":[{"key":"ref_1","unstructured":"Burley, J., Evans, J., and Youngquist, J.A. 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