The trees we sample

Not all trees are suitable for dendrochronology.  We need to know that the data we have relates to a particular year.  This means that we rely on trees with one ring per year, and not all trees have one ring per year.  Australia's Eucalypts are probably almost considered a 'notorious example' pf trees that don't have annual rings.  While you can see what I call growth bands in them, these are often ill-defined and not annual.  This is not to say there won't be some Eucalypts in some places that have annual rings.  For example, some of the high elevation Eucalypts show great promise in this respect.

However, the trees most used for dendrochronology in Australia and New Zealand are:

Australia: Huon Pine (Lagarostrobos franklinii), King Billy Pine (Athrotaxis selaginoides), Pencil pine (Athrotaxis cupressoides), Callitris columellaris, Celery Top Pine (Phyllocladus aspleniifolius), Red Cedar (Toona ciliata), and Plum Pine (Podocarpus lawrencii).

New Zealand: Pink Pine (Halocarpus biformis), Silver Pine (Lagarostrobos colensoii), Nothofagus species, Kauri (Agathis Australis), Phyllocladus species, Dracophyllum species

Several other species are under investigation, and there have been some initial promising results for species like Agathis robusta (Kauri) and Araucaria cunninghammii (Hoop Pine) in Queensland and Eucalyptus pauciflora in the Australian Alps. We will keep looking for more suitable species!