3.2 Time-since-fire effects
We found significance for time-since-fire on the effect for nitrate, with higher nitrate pseudo yield in burned watersheds (lmer:p-value: < 0.05; Fig. 2, Table S1). To get a rough approximation of how nitrate dynamics changed on an annual basis, we performed a Sen-Theil linear regression model on the percent difference through time (Hurtado, 2020). Nitrate increased across all sites by an estimated 29% per year (Fig. S7). Interestingly, the variability of the effect size of nitrate was significantly different (Levene’s test: F-value: 2.65, df: 6,95, p-value < 0.05) through time, with greater variability immediately following a wildfire and then becoming constrained further through time (Fig. S8). Similarly to nitrate, we found significant effects of time for DOC; however, with opposite directionality as DOC pseudo yield in burned watersheds was lower for at least five years (lmer : p-value: < 0.05; Fig. 2, Table S2). On average, DOC was lower by 25% in the burned compared to the unburned watersheds through the first 5 years, with no significant difference with >10 years. DOC decreased across all sites by an estimated 3.2% per year (Fig. S9). Additionally, the variance of the effect size through time was not significantly different (Levene’s test: F-value: 0.65, Df: 6, 48, p-value > 0.05; Fig. S10).