 B. verticillata plants are generally killed by fire and regenerate from seed . A field study after a mild fire in <unk> National Park published in 1994 found that plants burnt by fire were ten times as likely to have seedlings come up under their crown as unburnt plants ( with an average of 25 @.@ 2 seedlings per burnt plant ) , and burnt spikes released double the number of seeds as unburnt spikes . Despite this , <unk> recruitment ( seedlings arising between fires ) has also been recorded , and might be more common than in other Banksia species . Observations at several of the populations showed many plants produced their first seed anywhere from 13 to 17 years of age , leading to a recommendation of 20 years between fires to allow seed banks to accumulate . If fire occurs too frequently , plants are burned before reaching maturity or before they have produced sufficient seed to ensure regeneration of the population . This may cause a population decline or even local extinction . Too long a time between fires also causes population decline , as more plants die of natural attrition without releasing their seed , resulting in seed wastage . 
