Odds of beetle attack

Estimated odds ratio (solid curves) and 95% confidence bounds (dashed curves) describing the increase in odds of a beetle attack (a) as the number of trees attacks by beetles in the previous year increase from zero to 10, 000 trees/km2 (left panel) and (b) as the size of a fire in the previous year, and within one km of the infestation, increases from 0 to > 2500 ha (right panel). The hatched marks in the bottom of the right panel indicate distribution of observed fire sizes. Note that only 4 fires of size > 1000ha were observed in the sampled data.