## 2 Materials and Methods  
### Study Sites  
All study plots were located on the island of Lesvos, Greece, and were part of the permanent forest-plot monitoring network maintained by the Department of Environment, University of the Aegean. The climate of the island is characterised by long zero-thermic periods and mild wet winters. The dry season begins in mid-April and ends in early October. The average annual temperature on the island is approximately 18.0 \({}^{\circ}\)C, with the minimum monthly temperature in January (6.8 \({}^{\circ}\)C) and the maximum monthly temperature in mid July (31.0 \({}^{\circ}\)C). Mean total annual precipitation is 645 mm, with most rainfall occurring in December and January (Hellenic National Meteorological Service) and a spatial variation from 725 mm in the eastern part to 415 mm in the western part of the island [44]. In this study, we used data from nine plots (four post-fire and five elevation gradient plots). In four of the study plots, tree-growth/mortality and stand structure data have been recorded since their establishment in early 2019 (Figure 1). These plots were established across a post-fire chronosequence [43] at the central-eastern part of the island, where forests are dominated by _Pinus brutia_ (Table 1). The time since the last stand-replacing fire ranged from 13 to 92 years, with all the plots having similar elevations (166 to 316 m asl), mild slopes (under 10%) and soil parental material (Ophiolite). All four plots appeared to experience similar climatic conditions, with their long-term growth patterns well synchronized [45]. In these plots, soil respiration measurements were taken on a monthly basis. Five additional permanent monitoring plots, also dominated by _P. brutia_ and established across an elevation gradient, were used in this study for model validation purposes. These plots are located on the central part of the island of Lesvos (Mount Olympos, Figure 2) at elevations ranging from 350 to 750 m asl, with a sequential elevation difference of 100 m. In these plots, we monitored only biometric parameters related to the structure of the stand, with long-term tree growth data also available from the analysis of annual tree-rings [45]. All five plots were established on similar parental material (Ophiolite) with a soil depth range from 20 to 40 cm (Table A3). Figure 1: Distribution of the four plots with different amounts of time since the last stand-replacing fire on the island of Lesvos. The dominant tree species in all plots was _P. brutia_. See Table 1 for additional plot information. The coordinate system is WGS 84. In each of the 9 study plots, air temperature and relative humidity were recorded for a period of almost three years, using iButton Hygrochron DS1923-F5# (iButtonLink, Whitewater, WI, USA), with a 5 h time step. All sensors were placed on a tree within the plot (at a height of 2 m) facing north. In a subset of the plots (5), soil temperature at 15 cm was also recorded. These data were used to calculate the daily mean, minimum and maximum air and soil temperature, and the average air RH, between July 2020 and July 2023. Across plots, mean annual temperature (T\({}_{\text{A}}\)) varied between 17.4 and 12.6 \({}^{\circ}\)C, with mean annual relative humidity (RH\({}_{\text{A}}\)) between 62.49 and 79.84% (Table 2). The daily average air temperature (T\({}_{\text{mean}}\)) data were used to estimate the local lapse rate (\(-0.638\)\({}^{\circ}\)C/100 m), which was used to correct for temperature differences between plots, while a linear relationship between daily average soil temperature (T\({}_{\text{s}}\)) and air temperature was also developed.