The objective of this work was to determine the properties of particleboard panels made of “in natura” sugarcane bagasse particles, heated at 250 °C for 5 minutes. Various particle proportions were utilized to produce the panels and their properties were compared with that of a panel made of Pinus sp. The panels were produced with 8% tannin formaldehyde adhesive, and 0.5% paraffin emulsion, being pressed at 32 kgf.cm^-2 for 10 minutes at 180 ° C. It was determined the basic density of the “in natura” and heat-treated particles, their chemical composition, as well as the compression ratio necessary to obtain panels with density equal to 0.75 g.cm^-3. The basic density of the panels, hygroscopic equilibrium humidity, thickness swelling, linear expansion, water vapor adsorption, modulus of elasticity and rupture, perpendicular traction, screw pullout, and Janka hardness were determined. The basic densities of Pinus particles and sugarcane bagasse without and with heat treatment were 0.46, 0.27 and 0.30 g.cm^-3, respectively. The average specific mass of the panels was 0.74 g.cm^-3 with no significant difference between them. Generally, panels made of sugarcane particles were less hygroscopic and dimensionally more stable than panels made of Pinus particles. However, the perpendicular tensile strength, screw pullout and Janka hardness of these panels were higher than for the Pinus panels. The heat treatment of sugarcane bagasse particles resulted in better mechanical properties of perpendicular traction and Janka hardness. In general, the panels are within the limits set by ANSI A208.1. It is therefore possible to replace panels made of Pinus particles for the ones made of sugarcane bagasse, provided that at least 25% of the particles are heat treated for 5 minutes at 250 ° C.

The basic wood density influences the carbon stock, playing a crucial role in climate-changing global mitigation through carbon sequestration. Understanding wood carbon release depends on the Nitrogen assessment and CN ratio. Therefore, our research aimed to: (i) Compare basic density, organic carbon, nitrogen, and C/N ratio among the Khaya grandifoliola, K. ivorensis, and K. senegalensis; (2) Analyze the gradient along positions and diameter of the commercial stem; (3) Recommend the most representative sampling position for each species based on the diameter. The experimental area is located in Southeastern Brazil. Twelve average-diameter trees per species were cut down, and wood disc samples were collected at 0, 25, 50, 75, and 100% commercial height. Our results show statistical differences in wood basic density among the species, and K. senegalensis has the highest basic density, 592 kg m³. There was no statistical difference in organic carbon between species and along the stem. Stem diameter instead of commercial height improved the variable studied, confirming the research hypothesis. Sampling at 17% of the commercial height, ranging to 18–22 cm stem diameters, is recommended for greater representativeness.

The objective of this study was to evaluate the quality indicators for wood and charcoal from the Eucalyptus urophylla x Eucalyptus grandis hybrid (Clone GG 100) in different planting spacings. The study was conducted with the hybrid using the spacings of 2×1, 2×2, 3×2, and 3×3 m. The chemical properties of wood and charcoal were analyzed, and dry wood mass and energy per hectare were estimated. The data were subjected to the t test for comparison of means. Moreover, principal component analysis was conducted to assess the relationships between wood and charcoal indicators as a function of spacing.

Wood from reforestation gains market value due to its sustainable and legal origin. Planted forests in Brazil play a crucial role in economic, social and environmental aspects, with Eucalyptus and Pinus dominating the timber sector. However, non-majority species, such as those of the Khaya genus, have attracted great commercial interest due to the quality of their wood, being seen as an alternative to Brazilian mahogany. This study aimed to evaluate the biomass production of Khaya spp. stands and the nutrient uptake impacts in different harvesting scenarios. The research area is in Reserva Natural Vale (RNV) in Sooretama, Espírito Santo state, Brazil. The study was conducted 9.5 years after the planting of the Khaya spp. monoculture at a spacing of five m × five m, and the base fertilization consisted of 150 g of yoorin thermophosphate and 15 g of FTE BR 12 per seedling. The seedlings were of seminal origin, coming from different regions of Brazil and corresponding to three species: Kkaya grandifoliola C.DC (Belém-PA), Khaya ivorensis A. Chev. (Linhares-ES) and Khaya senegalensis A. Juss. (Poranguatu-GO). K. senegalensis exhibited the highest percentage of bark, while K. ivorensis was found to have the highest percentage of leaves. The biomass of the stems and branches did not vary by species. The relative biomass proportions had the following order: branches > stems > bark > leaves. The stocks of Ca and Mg were higher for K. grandifoliola, exceeding those for K. senegalensis (22.1%) for Ca and for K. ivorensis (42.3%) for Mg. The lowest nutrient uptake occurred in the scenario in which only the stem was removed, with averages of 44.17, 10.43, 21.93, 52.59 and 9.97 kg ha⁻¹ for N, P, K, Ca and Mg, respectively. Compared to total biomass harvesting, this represents a reduction in export levels by 91.34% for N, 79.31% for P, 94.66% for K, 94.29% for Ca and 93.28% for Mg. The nutrient uptake assessment demonstrated that more conservative harvest scenarios resulted in lower nutrient losses, indicating the importance of forest management practices that prioritize soil and nutrient conservation. In summary, the findings of this study provide a solid basis for the sustainable management of Khaya spp., highlighting implications for productivity and nutrient dynamics on a small or medium scale.

Tree cultivation spacing can influence productivity and wood quality, with silvicultural, technological and economic implications. This study aimed to estimate the production and provide an economic analysis of Eucalyptus urophylla × Eucalyptus grandis stands as a function of planting spacing in a small rural property. The study was carried out in the Zona da Mata of Minas Gerais state, with the hybrid clone (GG100) established in 2 × 1 m, 2 × 2 m, 3 × 2 m and 3 × 3 m spacing. Inventories were carried out at 14, 54 and 84 months in four plots from each spacing, with 24 plants. Diameter at breast height (DBH), total height and survival rate were evaluated. The study evaluated the logistic model of growth and yield for the different spacings and analysed production costs, characterising the expenditure elements related to inputs and labour. For the economic analysis, we considered a discount rate of 8% p.a. and the valuation methods of net present value (NPV), annual equivalent value (AEV), average production cost (APC), and cost–benefit ratio (CBR). Spacing influenced diameter distribution, tree height and productivity. The optimal harvest age showed a tendency to decrease in smaller spacing. The increase in plant density (smaller spacing) did not promote a proportional increase in volumetric production. Our results indicated economic viability from 60 months onwards for all spacing, except for 2 × 1 m.

The objective of this study was to assess the dynamics of carbon and nitrogen in soil, forest floor, and aboveground biomass in 9.5 years-old planted stands of three Khaya spp. (K. grandifoliola, K. ivorensis, and K. senegalensis). The study was conducted at the Reserva Natural Vale (RNV), Brazil. The stands were planted at 5 × 5 m spacing, distributed over rectangular plots of 1250 m². Soil bulk density at the evaluated depths, as well nitrogen contents, were similar among the species. However, K. ivorensis exhibited higher carbon concentration in the soil. In general, there were no differences in carbon and nitrogen content in soil between the three species; however, the values obtained are comparable to those of the reference area–Native Forest. The carbon stocks in the aboveground biomass for K. grandifoliola, K. ivorensis, and K. senegalensis averaged 37.97, 33.66 and 33.86 Mg ha⁻¹, respectively (p ≤ 0.05). These values collectively represent about 28% of the total carbon stocks across the observed compartments. Notably, the nitrogen content within the aboveground biomass did not differ among these species. Therefore, African mahogany possesses a robust potential to store both carbon and nitrogen.