Kauri Fossils and Subfossils as a Paleoclimate Data Collection Tool 

KAURI AS A PALEOCLIMATE DATA COLLECTION TOOL

Kauri (Agathis australis) are coniferous trees which have populated the Southern Hemisphere for nearly 20 million years. They are currently native to tropical forests in Australia, New Zealand, Papua New Guinea, New Caledonia and other surrounding regions. Modern Kauri are found in montane forests while the Ancient Kauri are found buried in swamps, preserved in peaty sediment. Researchers believe that Modern Kauri are not found in the same ecological setting as Ancient Kauri because human logging efforts eliminated the low altitude populations. Modern kauri trees are often close to 600 years old with it not being uncommon for them to reach ages of over 1000 years. Kauri trees can act as reliable climate proxies because they are responsive in their growth pattens to changes or stresses in the environment which can be observed in the width of their tree rings. Due to their extensive ages, a single kauri tree’s ring chronologies can span several hundreds or even thousands of years. Kauri also disperse pollen which is easily identifiable in sediments, and when conditions are right, the kauri pollen is well preserved. Despite the crowns of these giant trees reaching impressive heights, their pollen is not widely dispersive and as such the presence of kauri pollen in a stratigraphic section is indicative of living trees in that location at the time of deposition. Preserved fossil or sub-fossil Kauri wood indicates that a tree or population experienced a mortality event. Dendrochronology using Ancient Kauri is a relatively new science and there are wide gaps in the historical database; however, through crossmatching the dendrochronological data of different samples, the puzzle of kauri paleoclimate data can be pieced together slowly. The use of kauri as a paleoclimate record is beneficial for several reasons; however, the fact that kauri is tree which is exclusively native to the southern hemisphere means that it also functions to provide paleoclimate data outside of the northern hemisphere. This helps counter some of the Northern hemisphere bias in data collection (especially within the field of dendrochronology). The kauri paleoclimate records need to continue to be updated and compared against each other in order to maintain and build The data within kauri fossils and subfossils is of incredible detail and as such is an immensely valuable resource for data collection. It is truly amazing how kauri can accurately record information about changes during climate fluctuations, information which has become evermore valuable as we now push forwards into a time of great climate uncertainty.

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