# Effects of Precipitation and Fire on Land Surface Phenology in the Brazilian Savannas (Cerrado)
## 4 MODIS LSP metrics
### Pre- and Post-Fire Behavior of NDVI-Derived LSP Metrics from the MOD13Q1 and HLS Products
At the bottom, the locations of the selected control (non-burned) and burned sites are shown on the image from 24 July 2021. Burned areas are shown in dark blue, while vegetation recovery in these areas is depicted in red. A detailed analysis of the 2021 fire impact on the TIMESAT determination of phenological metrics, using the reprocessed 5-day 30-m harmonized HLS product, revealed the NDVI temporal patterns with grassland burning and subsequent vegetation recovery (Figure 13). By comparing a burned site with a neighboring control (non-burned) site in savanna grasslands (site location indicated in Figure 10), we observed a substantial decrease in NDVI, dropping from approximately 0.40 to 0.10 on 10 July 2021, when the fire began during the local dry season of the 2020/2021 cycle (dashed circle in Figure 13). After the start of the rainy season in October 2021, marking the beginning of the following seasonal cycle (2021/2022), vegetation starts to recover strongly, leading to an increase in NDVI towards December, when similar NDVI values were observed between the control and burned sites (dashed square in Figure 13). From December until the end of the following 2021/2022 dry season in September 2022, the recovery of grasses led to higher NDVI values in the burned areas compared to the control site. Comparable NDVI values between the control and burned sites were observed in October 2022 with the beginning of the new 2022/2023 seasonal cycle (Figure 13). Therefore, the impact of burned areas on the decrease  
Figure 12: Interannual variations in the MODIS Land Surface Phenology (LSP) metrics (**a**) Amplitude (AMP) and (**b**) Small Seasonal Integral (SSI) in savanna grassland (red line) and woodland (green lines) areas from the EMAS National Park (ENP). Three major fire events during this period are highlighted by colored shaded columns: 1 September 2005 (affecting 45% of the park’s area), 12 August 2010 (90%), and 10 July 2021 (21%). in NDVI was observed during the 2020/2021 cycle (disturbance cycle), while vegetation recovery effects became evident in the following seasonal cycle (2021/2022). These effects were minimal during the 2022/2023 cycle. Compared to grasslands of the burned site, the structural and floristic composition of some burned woody species may take more years to recover, as will be discussed later. The analysis of the fire's effect size on the HLS-derived NDVI phenological metrics confirmed the MODIS results from Figures 11 and 12. To illustrate this, we plotted the Hedge's effect size metric (Figure 14). The results showed the statistical differences for each LSP metric between control and burned sites, considering the seasonal cycles before the fire (2019/2020), during the fire event (2020/2021), and after the fire (2021/2022 and 2022/2023 cycles). Positive values of Hedge's G indicated that the values of the control site were higher than those of the area affected by the fire. When considering the Hedge's G values outside the limits defined by the shaded horizontal bar in Figure 14, which represents an indirect measurement of uncertainties in the control site, the most affected phenological metrics were BL, VES, and VSS, which decreased in burned areas during both the 2020/2021 and 2021/2022 seasonal cycles. The effects on VSS were notably stronger in the seasonal cycle following the fire event, as indicated by the relative behavior of the red (2020/2021 cycle) and magenta (2022/2023 cycle) lines in Figure 14 for this metric. In contrast, metrics such as AMP and SSI increased as a result of the fire impact in these two cycles (Figure 14). The effect size analysis also identified EOS as a sensitive metric to fire-affected areas. However, upon reviewing Figure A3 in Appendix A, we observed that the average EOS showed only small differences (approximately 10 days) between control and burned sites for both the pre- and post-fire seasonal cycles.