Table 4. Output of a Weibull model investigating the effects of fire severity, pre-fire size and site on post-fire resprouting volume.
Effects include fire severity scored at the base of each shrub (Firebase; orthogonal polynomial contrast trend test; L, linear; Q, quadratic; C, cubic), pre-fire size (Prefiresize), site, fire severity × site interaction and pre-fire size × site interaction. Sigma represents the coefficient for dispersion (variance). Models were fitted using treatment contrasts with Cape St. Francis as the reference level for Site comparison with Knysna (KNS).
| Resprouting volume | Regression coefficients are natural logarithms, standard errors are in brackets |
|---|---|
| (Intercept) | 12.61 (0.16)*** |
| Firebase.L | 0.58 (0.22)** |
| Firebase.Q | 0.09 (0.18) |
| Firebase.C | −0.09 (0.16) |
| Prefiresize | 0.91 (0.22)*** |
| SiteKNS | −1.03 (0.21)*** |
| Firebase.L:SiteKNS | −1.91 (0.27)*** |
| Firebase.Q:SiteKNS | 0.15 (0.23) |
| Firebase.C:SiteKNS | 0.18 (0.20) |
| Prefiresize:SiteKNS | 1.65 (0.38)*** |
| sigma (Intercept) | −0.47 (0.02)*** |
| Num. obs. | 1,112 |
| Nagelkerke R2 | 0.19 |
Notes:
*
p < 0.05.
**
p < 0.01.
***
p < 0.001.