## Materials and Methods
### Test of DBSS in Field Conditions  
BVOC samplings were carried out in two different experimental sites, utilizing SPME fibers with both the static and dynamic sampling system (DBSS). The first sampling site was located in the experimental fields of CNR (National Research Council of Italy, 43\({}^{\circ}\)49\({}^{\prime}\)05\({}^{\prime\prime}\) N, 11\({}^{\circ}\)12\({}^{\prime}\)12\({}^{\prime}\) E, Sesto Fiorentino, FI, Italy) on the 5 th of June 2019. BVOCs emissions were collected from 15 3-year-old _Quercus_ _lex_ L. potted plants (kindly supplied by Vivaio Matteini, 51100, Pistoia) maintained under optimal irrigation (sampling point 1). The heights of individual plants were about 120 cm with a stem diameter of 1 cm (Table 2).  
The second experimental site was located in the Maremma Regional Reserve at 320 m altitude (Alberese, 42\({}^{\circ}\)38\({}^{\prime}\)10\({}^{\prime\prime}\) N, 11\({}^{\circ}\)05/39\({}^{\prime\prime}\) E, Grosseto, GR, Italy), and BVOCs emissions were collected on the 20 th of June 2019 (sampling point 2) and on the 1 st of October 2019 (sampling point 3) (Table 2). This site was characterized by a Mediterranean sclerophyll forest with the predominance of _Q.__lex_, representing around 70% of the total number of individuals. At this site, SPME fibers were placed under the tree canopy, and the BVOC collection was carried out with the same settings mentioned above.  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Sampling** & **Sampling** & **Temperature** & **Humidity** & **Wind** & **Sampling** & **Plants** & **Site** \\
**Point** & **Day** & & & speed & & & \\ N & dd/mm/yyyy & \({}^{\circ}\)C & \% & (km/h), & & & \\  & & & & direction & & & \\
1 & 6/6/2019 & 24 \({}^{\circ}\)C & 45\% & 9–14 km/h, & 12 pm 4 pm & _Q.__lex_ in pot &
\begin{tabular}{c} Sesto \\ Fiorentino (FI) \\ Maremma \\ (GB) \\ Maremma \\ (GB) \\ \end{tabular} \\
3 & 1/10/2019 & 20 \({}^{\circ}\)C & 60\% & 8 km/h, S & 12 pm 4 pm & _Q.__lex_ forest &
\begin{tabular}{c} Sesto \\ Fiorentino (FI) \\ Maremma \\ (GB) \\ Maremma \\ (GB) \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table}
Table 2: The table shows the main atmospheric and sampling parameters: days of sampling, atmospheric temperature and humidity, speed and direction of wind, time window of sampling and site characteristics.  
At both sampling sites, BVOC collection was conducted during rainless days and with light wind. The air temperature and humidity, as well as wind speed and direction, were recorded by weather stations installed in the proximity of the sampling sites by the Institute of Bioeconomy of the National Research Council of Italy (IBE, CNR). BVOCs were collected on DVB/CAR/PDMS coating fibers for 4 h, from 12 am to 4 pm, to cover the time interval with the highest presumable concentration of terpen in the air as indicated in literature [60; 61]. Indeed, several authors have shown a diurnal cycle in BVOCs emissions [55; 56; 57], with higher emissions between 9 am and 5 pm and a maximum peak around 1-2 pm [56]. The fibers were positioned at a height of 40-45 cm from the ground using a plastic band to connect them to a metal picket and at a distance of 30 cm from _Q. ilex_ plants. All measurements were conducted in triplicate.