# Near-Real-Time Detection of Insect Outbreaks in Urban Trees Using a PlanetScope Time Series
## 2 Materials and Methods
### Field Data Survey: Geographical Location of Pinus pinea  
All the green areas with the presence of _P. pinea_ of Rome are attacked by _T. parvicornis_ (Figure 2). An in situ survey was conducted to create a reference dataset and to restrict the analysis to tree species affected by the infestation (_Pinus pinea_), excluding all others. Surveys were conducted between June and August 2023 at the selected sites (Figure 1 and Table 1). During each inspection, every stone pine in the chosen areas was classified according to the infestation status and georeferenced. A point shapefile was created where each point represents a tree classified as infested or healthy. \begin{table}
\begin{tabular}{c c c c} \hline
**Location** & **Name of Area** & **Number of Trees** & **Number of** **Suitable Trees** & **Date of Survey** \\ \hline \hline \multirow{3}{*}{} & Parco degli acquedotti * & 130 & 126 & 16–29 June 2023 \\ \cline{2-4}  & Villa Ada & 30 & 30 & 21 June 2023 \\ \cline{2-4}  & Parco Don G. Alberione & 16 & 16 & 23 June 2023 \\ \cline{2-4}  & Villa Borghese * & 340 & 332 & 21 June–29 July–27 August 2023 \\ \cline{2-4}  & Green area via D. Campana & 10 & 9 & 7 June 2023 \\ \cline{2-4}  & Via delle Terme di Caracalla * & 106 & 91 & 17 June 2023 \\ \cline{2-4}  & Parco G. Sbragia * & 47 & 47 & 23 June 2023 \\ \cline{2-4}  & Parco E. Corizza & 16 & 16 & 6 June 2023 \\ \cline{2-4}  & Villa Clori * & 202 & 193 & 21 June–22 July 2023 \\ \cline{2-4}  & Villa Lazzaroni & 37 & 37 & 18 June 2023 \\ \cline{2-4}  & Parco Papacci * & 49 & 49 & 10 June 2023 \\ \cline{2-4}  & Villa Pamphili & 574 & 528 & 27 June–11 July–23 July–28 July–10 August 2023 \\ \cline{2-4}  & Parco Petroselli & 19 & 19 & 7 June 2023 \\ \cline{2-4}  & Parco Don Giovanni Scorza & 40 & 32 & 16 June 2023 \\ \cline{2-4}  & Pineta Sacchetti * & 331 & 231 & 27 June–8 August 2023 \\ \cline{2-4}  & Street-side trees in Saxa Rubra & 41 & 39 & 10 June 2023 \\ \cline{2-4}  & Giardino Aldo Tozzetti & 7 & 7 & 7 June 2023 \\ \cline{2-4}  & Parco Tor Tre Teste & 28 & 27 & 7 June 2023 \\ \hline \hline Tuscany region, Pisa & Tenuta San Rossoe * & 238 & 238 & 10 September 2023 \\ \hline \end{tabular}
\end{table} 
Table 1: A list of the locations visited, accompanied by dates of surveys and plants surveyed within each area. The ones with * were selected for the analysis. Figure 2: Examples of infested areas: (**a**) Villa Borghese, (**b**) Pineta Sacchetti, and (**c**) twig with _T. parvicornis_. The fully digital data-recording methodology enabled the direct use of these data using QGIS 3.16.15 and the Google Earth Engine. In this initial phase, the process was structured into several successive surveys, leading to visits to more areas than were ultimately chosen for the study. Indeed, it was necessary to assess the actual visibility of satellite images, overlapping the georeferenced data with the PlanetScope images (Figure 3). In addition, a significant number of areas were affected by the presence of dead or felled trees, which diminished the number of suitable trees available for analysis (Table 1). This reduction in tree density compromised the effectiveness of remote sensing in these regions. Consequently, any areas where canopy cover was thinned (e.g., trees along roadways or spaced too far apart) were excluded. This approach allowed for the selection of only proper areas for detailed analysis, thereby ensuring a sufficient sample size for combination with remotely sensed data. As the considered insect has infested all green areas of Rome (Latium Region), a control area was established in a non-infested area close to the city, with size and characteristics (e.g., uniformity of tree species) appropriate for the analysis: the Tenuta San Rosorse, a section of the Regional Park of Migliarino, San Rosorse, and Massaciuccoli, a protected area located in Tuscany, between the provinces of Pisa and Lucca.