These where observed during a holiday in Western Australia near the city of Perth in February 2019. I assume they are tree seed pods. But from which tree?
I don't know the exact species, but this is likely to be a Hakea species. These are a widespread genus of plants in Australia, with a hard persistent woody seed that splits open after heating (usually fire) or plant death (as in your case) to release two seeds.
You can see some photos of seed pods at Project Noah, showing the classic bifurcate seed pod.