adansonia-gregorii Australian-baobab Australian-boab barrel-trunk boab boab-tree bottle-tree brown-gray brown-grey damage damaged dead-rat-tree deciduous diseased distinctive gadawon gouty-stem-tree grotesque indigenous Kimberley-native large pitted recovery repairing self-repairing shape slow-growing smooth-bark soft-fibrous-wood surface surfaces texture textures trunk useful water-retention wounded wounds