Table 1.
Pearson’s correlation coefficients between reconstructed fire regime history and main climatic variables
| Variables | Fire season length | Spring temperatures | Spring precipitation | Annual precipitation | March insolation | Summer insolation (July, August, September) | RegBB | RegFF | FS index |
| Fire season length | 1 | ||||||||
| Spring temperatures | −0.576 | 1 | |||||||
| Spring precipitation | −0.832** | 0.670** | 1 | ||||||
| Annual precipitation | −0.913*** | 0.827** | 0.865*** | 1 | |||||
| March insolation | −0.794** | 0.781** | 0.740** | 0.836*** | 1 | ||||
| Summer insolation | 0.823** | −0.792** | −0.816** | −0.865*** | −0.976**** | 1 | |||
| RegBB | 0.104 | −0.237 | 0.167 | −0.096 | −0.472 | 0.316 | 1 | ||
| RegFF | 0.432 | −0.576 | −0.267 | −0.475 | −0.827** | 0.723* | 0.857** | 1 | |
| FS index | −0.809** | 0.753** | 0.895*** | 0.856*** | 0.860**** | −0.927**** | 0.021 | −0.475 | 1 |
April to June for spring and July to September for summer. Significant correlation coefficients are in boldface type with P values reported as follows: *P < 0.1; **P < 0.05; ***P < 0.01; ****P < 0.001. Significance was determined using permutation tests with correction for multiple comparisons (SI Text). Sample size is n = 8 millennia.