Fire in the Dunes by Heather Reeves. All Rights Reserved. This section of the Lancelin sand dunes in Western Australia shows the effect of fire on the grass trees (Xanthorrhoea) growing in this area. They are starting to show some green, indicating that there has been only one fire here. Fire often does not kill in one instance, but repeated fires definitely do. Lightning strikes are the cause of some fires; more often they are set by people, sometimes accidentally but too frequently on purpose. There is not much that will grow on nutrient-poor sand, so it is important for the dunes that the trees survive.