## 2 Volatile Wood Composition
### _Q. pyrenaica_ Wild
The last two compounds were only found in acacia wood, presenting contents of 1.24-1.83 and 14.90-16.7 \(\upmu\)g/g, respectively, in seasoned wood and 0.72-1.17 and 89.3-91.7 \(\upmu\)g/g in toasted wood, so it could be said that they are characteristic of this wood [23; 65]. In addition, resorcinol, a compound never detected in wood, was detected in acacia [65]. However, acacia wood both after seasoning and toasting does not possess certain volatile compounds found in _Quercus_[23] such as methyl benzoate, methyl homovanillate, methyl vanillate, methyl syringae, isobutyrovanillone, _trans_ and _cis_ lactones, these lactones being of special interest for providing aromatic notes of coconut to the wines. As in other non-_Quercus_ wood (cherry, chestnut and ash), the contents of most of these compounds increased during toasting, as well as those of phenyl alcohols, while in _Quercus_ wood they decreased or did not change [23]. However, other compounds decreased in concentration during toasting in acacia wood such as: 3,4-dimethoxyphenol, 3,4,4-trimethoxyphenol, acetic acid, hexanoic acid, hexadecanoic acid and 1-hexanal [23; 65]. Castanea sativa (Chestnut)  
This wood has been widely used for oenological purposes in the Mediterranean area in the past due to its wide availability and low cost. Moreover, it is the only non-Quercus species accepted for use by the OIV. This wood, after being seasoned, is distinguished by its phenolic aldehydes/phenyl ketones content (Figure 1b) and has the same or even higher contents of volatile phenols and furanic compounds than traditional woods. Like the other non-Quercus woods, they lack lactones. The compounds generally increase during toasting; the higher the toasting, the higher the content. These increases during toasting are very significant in acacia, chestnut and ash wood, especially in chestnut wood, which is the richest as a whole, in compounds derived from lignin, lipids and carbohydrates [23]. Chestnut wood showed higher contents than _Quercus_ wood, especially when toasted at 180 \({}^{\circ}\)C for 45 min, in compounds such as volatile phenols (guaiacol, 4-VG, eugenol, isoeigenol and syringol), furanic compounds (furfurfural, 5-MF, 5-HMF, 5-acetoxymethyl-2-furfural, 1-methoxy-2-ethoxyethyl-1-furan) and phenolic aldehydes/phenyl ketones (vanillin, syringaldehyde, acetovanillone, butyrovanillone, propiovanillone, propiosyringone, butyl-rosyringone, isoacetovanillone, isopropoiovanillone, isoacetosyringone, isopropiosyringone, methyl homovanillate and acetophenone) [23]. All this indicates that it is a very rich wood aromatically after toasting, especially after medium toasting (Figure 1c). This figure shows how this wood is more aromatic than traditional and other woods in furanic compounds and phenolic aldehydes/phenyl ketones, and the content of volatile phenols is higher than _Quercus_, but it is not the richest wood in these compounds. However, coconut notes would not be contributed or would play an insignificant role with these woods, since in their composition, according to some authors, neither of the two lactone isomers were found [23], and according to others, they were found in low concentrations (<0.7 \(\upmu\)g/g) [65]. Prunus avium (Cherry)  
The composition of cherry was studied after 24 months of seasoning and after light and medium toasting [23; 65]. In cherry wood, p-anisaldehyde, p-anisylacetone, p-anisyl alcohol, 7,8-dihydro-3-oxo-\(\alpha\)-ionol, 7,8-dihydro-4-oxo-\(\beta\)-ionol and benzyl salicate, not found in any other woods, were found, so these compounds could be considered characteristic of cherry wood. Of these compounds, p-anisaldehyde and benzyl salicate were the ones found in the highest concentrations. The p-anisaldehyde increased significantly during toasting from 0.18-0.33 \(\upmu\)g/g in dry wood to 0.45 \(\upmu\)g/g after light toasting to 4.36-4.41 \(\upmu\)g/g after medium toasting, while benzyl salicate decreased during this process from 4.46-7.67 \(\upmu\)g/g in dry wood to 0.61-0.68 \(\upmu\)g/g in wood after medium toasting.