Among the parameters used in the biomass carbonization process, the heating rate is one of the most important. The objective of the present work was to assess the influence of different heating rates on the chemical composition of wood vinegar (WV) from two wood species. Dried disks of Eucalyptus grandis and Mimosa tenuiflora wood were used as raw material. Carbonization runs were carried out in a laboratory muffle furnace at three heating rates (0.7, 1.0 and 1.4 °C/min), with 10 runs at each heating rate, reaching 450 °C. Yields of charcoal, pyrolysis liquids and gases were determined for all carbonization conditions. Crude pyrolysis liquid from each wood species and each heating rate was bi-distilled, yielding purified WV samples. These samples were extracted with ethyl acetate and the organic fraction was analyzed by gas chromatography-mass spectrometry to obtain qualitative and semi-quantitative data. Results showed that lower heating rates produce higher yields of charcoal, while higher heating rates lead to higher yields of pyrolysis liquids and gases. Totals of 57 and 42 chemical compounds were identified in the WV of Eucalyptus and Mimosa, respectively, divided into the following groups: alcohols, ketones, furans and pyrans, and phenolic compounds. In general, higher heating rates led to greater contents of furans and pyrans and lower concentrations of phenolic compounds.

Eucalyptus wood vinegar (WV) is a versatile natural product employed in several areas such as for agriculture, zootechnics, and veterinary applications. However, the product may contain contaminants such as polycyclic aromatic hydrocarbons, methanol, metals, and so on in its raw form. Thus, refining is required to remove them. Only after reaching a high-purity grade can WV be applied as a basis for pharmaceuticals, antimicrobials, and additives for animal husbandry. This work aimed to assess the effect of refining on the contaminant content of a WV produced on an industrial scale and traded as agricultural input in the Brazilian market. WV was refined by sequential vacuum distillations and had its contaminant contents assessed before and after refining. The following chemical classes were investigated: metals and other elements, insecticides, fungicides, and herbicides (carbamates, organochlorines, organophosphates, pyrethroids, and others), mycotoxins, polychlorinated dioxins and furans, polycyclic aromatic hydrocarbons, and volatile organic compounds, encompassing more than 100 chemical species. Also, the WV physical–chemical properties before and after refining were determined. Gas chromatography and mass spectrometry (GC/MS) were employed to attain the WV’s chemical profile. The main chemical components, such as phenolic compounds, furans, ketones, pyrans, etc., were annotated in the WV chemical profile. No traces of insecticides, fungicides, herbicides, heavy metals, mycotoxins, polychlorinated dioxins, or polychlorinated furans were found in raw WV or refined versions. However, several other undes/irable chemicals were determined in the raw product, such as PAHs and volatile organic compounds (acetaldehyde, acetone, ethylene glycol, and methanol). Nevertheless, all of them were effectively removed from the raw WV after the first or second sequential refining steps, resulting in a pure product. Therefore, only one refining step can be applied to raw WV to yield a high-quality product for pharmaceutical and animal husbandry applications.

The increase in demand for timber and global eucalyptus cultivation has generated controversy regarding its potential impact on water resources, especially in regions with limited water availability, with the myth that “eucalyptus dries out the soil” being spread. In this regard, this review study addresses the factors that influence water consumption by eucalyptus, providing solutions to reduce, mitigate, or even avoid any impact on water resources at a given site. In this manuscript, the authors reviewed 200 works published from 1977 to 2024 to survey all information to confirm if the factual background allows someone to state if eucalyptus can deplete soil water. With a solid scientific basis, many research studies show that eucalyptus’ water demand is comparable to that of native forest species and crops worldwide and that species, age, edaphoclimatic conditions, and forest management practices mainly influence water consumption. On the other hand, it is a hasty conclusion that some eucalyptus species can contribute to reduced soil water. Effectively, without proper management, the environmental impacts of a eucalyptus plantation are the same as those of poorly managed crops. Indeed, if cultivated with proper agroclimatic zoning and correct management practices, the growth of eucalyptus culture is an environmentally correct activity. By adopting measures such as maintaining sufficient native forest cover to ensure ecosystem services, cultivation based on zoning maps, and considering local specificities (e.g., deeper, sandier soils are preferable), selection of species appropriate to the carrying capacity of each region, adoption of lower planting densities, and reduced rotation, eucalyptus cultivation will not negatively affect water resources. Sustainable eucalyptus cultivation has several economic and environmental benefits, in addition to positive social impacts on surrounding communities in terms of employment and family income, and its sustainable management can guarantee its viability, demystifying the idea that eucalyptus trees cause water scarcity. The works reviewed herein demonstrated no solid ground to sustain the eucalyptus’ water depletion myth.