This study deals with the effect of heat treatment on Pinus oocarpa specimens from forest plantations in Colombia. The effects of two heat treatments at 170 and 190 °C for 2.5 h in saturated vapor were evaluated based on the color, dimensional stability, air-dry and basic densities, modulus of elasticity (MOE), and modulus of rupture (MOR) in static bending of samples. The evaluations were carried out following the Colombian Technical Standards NTC 290 and 663, and the color changes resulting from heat treatments were monitored using the CIE-Lab, as well as other standards from the literature. The results show that there was 2.4% and 3.3% mass loss of wood modified at 170 and 190 °C, respectively. The air-dry and basic densities were higher in 170 °C treatment than after 190 °C treatment, and the thermal modifications applied increased the dimensional stability of the treated wood. After treatment at 170 and 190 °C, the lightness to darkness (L*) was reduced by 10% and 22%; the a* coordinate increased by 11% and 26%, causing redness in the treated wood; the b* coordinate increased by 14% and 17%; and the values of the wood color saturation (c*) increased by 14% and 18%, respectively. The general color change (ΔE*) increased gradually with the increase in the treatment temperature, resulting in a high color change to a very different color. The bending strength of thermally modified wood was improved and significantly increased to values higher than those of unmodified Pinus oocarpa wood. The high air-dry and basic densities, improved dimensional stability and resistance to bending, and attractive appearance of the treated wood indicate that thermal modification is a promising alternative for the transformation of Pinus oocarpa wood into a raw material with a high added value.

Thermal modifications alter the physical properties and improve the natural durability of wood without using chemical impregnation processes being an environmentally friendly alternative; these improvements could be made due to changes in the internal wood structure. In this investigation, changes caused to the chemical composition and microstructure of wood Pinus oocarpa by thermal modification at 170 and 190 °C were evaluated. The thermal treatment was carried out in a prototype chamber operated during the modification steps under a steam atmosphere, with a continuous flow without pressure. The evaluation of chemical changes was performed following the TAPPI standards. Using Fourier transform infrared spectroscopy (FTIR) and optical microscopy, the wood microstructure was characterized. The results showed a decrease in holocellulose contents by 7% at 170 °C and by 9% at 190 °C; lignin contents increased at 170 °C (6%) and at 190 °C (8%) and extractives were increased by 8% (170 °C) and 13% (190 °C); the changes obtained by the spectra were related to the C-H deformation in cellulose and hemicelluloses and the complex bonds of lignin carbohydrates of the -CH3 (lignin) and CH2 (carbohydrates) groups and organic acids released during thermal modification. Thickness of tracheid walls decreased in earlywood 8% (170 °C) and 22% (190 °C) and in latewood 11% (170 °C) and 14% (190 °C); lumen diameters increased in earlywood to 170 °C (14%) and 190 °C (48%) and in latewood in 14% (170 °C) an in 20% (190 °C). At 190 °C, the cell alterations were higher. Pinus oocarpa was thermally modified at 170 °C showing better wood quality in its internal structure.

La presente investigación se desarrolló con la madera Pinus oocarpa Schiede ex Schltdl. Var. Ochoterenai de plantación forestal de Colombia, la cual presenta inconvenientes importantes que limitan su uso, debido a su poca estabilidad dimensional y resistencia mecánica. Los tratamientos con impregnación de polímeros pueden reducir las deformaciones, y mejorar las propiedades físicas y mecánicas. El objetivo de esta investigación fue evaluar el efecto de la impregnación de polietilenglicol con peso molecular 600 y 1500, alcohol polivinílico y adición de zeolita, sobre la densidad, estabilidad dimensional, flexión estática y compresión paralela al grano. Las muestras se impregnaron con baño caliente a 95 °C, durante 8 horas, y luego impregnados a temperatura ambiente, por 16 horas. La evaluación de la madera se llevó a cabo bajo las Normas Técnicas Colombianas y otros estándares de la literatura. Los mejores resultados se obtuvieron con la impregnación de polietilenglicol 1500; la densidad aumentó entre el 21 % y 24 %; la eficiencia anti-hinchazón fue de 60 %; en flexión estática aumentó el módulo ruptura 20 %, el módulo de elasticidad 39 % en compresión paralela al grano aumentó 8 %. La madera cambia de categoría a madera estructural, mejorando sus propiedades físicas y mecánicas. El tratamiento con polietilenglicol 600 proporcionó una menor eficacia anti-hinchazón (14 %), y menor mejora en densidad (8 %) y en las propiedades mecánicas (1 % a 7 %).

Timber from forest plantations is of great relevance to be used as a substitute for timber from natural forests; thus, reducing pressure on them and in such a way indiscriminate felling. Alternative building materials, like cross-laminated timber (CLT), are being sought in the world. In Colombia, the CLT production is not well-studied; thus, this investigation characterized the physical and mechanical behavior of cross-laminated timber (CLT) in three layers made with Pinus tecunumanii wood manufactured by Finger Joint and wood plank systems. In each of the CLTs, density, modulus of elasticity and modulus of rupture in static bending were evaluated. Both manufacturing systems produced CLTs with an air-dry medium density and low resistance to static bending. The CLT made with finger joints showed low elasticity, while the CLT made with a solid wood planks system showed medium elasticity. The results of this study, with wood match material Pinus tecunumanii showed higher values than those reported for other woods. Future studies should focus on determining changes in the physical and mechanical properties of CLT with quality-rated wood.

Colombia has numerous wood species of great importance; however, information on many of these species is scarce. For this reason, the woods Guaimaro (Brosimum lactescens) and Dormidero negro (Parkia discolor) cultivated in Calamar (Guaviare) were studied, with the aim of determining their properties and enhancing their rational use. The evaluations were carried out following the Colombian Technical Standards NTC 290, 663, 701 and 784. Density was evaluated according to NTC 290; shrinkage and stability coefficient were determined following the NTC 701; the holocellulose content was according to the procedure of Wise, the lignin content and extractives were determined as described by TAPPI T 222 and T 204; the mechanical bending strength with NTC 663 and to calculate the parallel compression under the NTC 784. The Guaimaro is a very dense wood, dimensionally stable and of high resistance to bending and parallel compression being of optimal use for construction with extractives of 18.52%, holocellulose of 65.59% and lignin of 35.81%; it presents higher lignin contents than other species of the same genus. The Dormidero negro has a medium density, low dimensional stability, and low resistance to static bending and parallel compression. It is not suitable for construction, but it can be used for carpentry. The chemical composition was consistent with that of other species in the same genus, with extractives at 15.88%, holocellulose at 69.30%, and lignin at 31.77%. Expanding mechanicaltests, such as hardness and shear tests, is recommended, along with exploring treatments to enhance its properties.

In Colombia, wood preservation treatments still rely on toxic and environmentally hazardous products, whereas cleaner and safer alternatives remain scarcely implemented. Thermal modification has emerged as a sustainable technology capable of enhancing wood resistance to biological degradation, improving dimensional stability, and optimizing its performance for industrial applications. Furthermore, this process enables the assessment of chemical and structural transformations associated with wood modification. Albizia carbonaria, a native Colombian species distributed in tropical and premontane humid forests, is commonly used in agroforestry systems associated with coffee cultivation. This study evaluated the effects of thermal treatments conducted in a closed system at 170 and 190 °C, temperatures at which significant changes are expected in low-density woods due to hemicellulose degradation and consequent alterations in the internal structure. Dimensional stability, density, chemical composition, and anatomical modifications were analyzed according to Colombian Technical Standards and Technical Association of the Pulp and Paper Industry (TAPPI) standards, using wood obtained from an agroforestry plantation. Mass loss reached 7.72 and 9.54% at 170 and 190 °C, respectively. Air-dry density (12%) was significantly higher at 190 °C, while dimensional stability improved under both treatments. In addition, holocellulose and extractives contents increased as a consequence of total mass reduction and the formation of new compounds. Anatomical alterations and cell wall thickening were also observed. However, the 170 °C treatment promoted greater density increases, higher chemical content, and lower anatomical damage, indicating that this thermal condition is more suitable for the species.