Pushing Pines to the Limit

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Pushing pines to the limit described in the Annals of Botany doi: 10.1093/aob/mcr135, published online 3 July 2011. Catherine Offord of The Australian Botanic Garden, Mount Annan, southwest of Sydney Australia has tested the upper and lower temperature limits for survival in a number of Araucaria species (Southern Pines) including the Wollemi pine. In the report entitled “Pushed to the limit: consequences of climate change for the Araucariaceae: a relictual rain forest family” Offord explains “the seven species found in Australia have limited natural distributions characterized by low frost intensity and frequency, and warm summer temperatures”. In the experiments Wollemi pines were the most frost tolerant and Kauri pines the least. All of the trees were damaged by temperatures above 47.5 degrees C. Offord concluded “While lower temperature limits in the Australian Araucariaceae are generally unlikely to affect their survival in wild populations during normal winters, unseasonal frosts may have devastating effects on tree survival. Extreme high temperatures are not common in the areas of natural occurrence, but upward temperature shifts, in combination with localized radiant heating, may increase the heat experienced within a canopy by at least 10 degrees C and impact on tree survival, and may contribute to range contraction. Heat stress may explain why many landscape plantings of W. nobilis have failed in hotter areas of Australia”.

Editorial Comment: Australian Araucarias are indeed a pathetic remnant of their previous abundance and distribution, as recorded in the fossil record and in history. Wollemi pines are now only found wild in one tiny valley in mountains west of Sydney. Others, such as Kauri Pines, Hoop Pines and Bunya Pines have a patchy distribution in warmer moist regions further north. But fossils of Araucarias are abundant in Jurassic rock layers, and both living and fossil versions can be seen at the Jurassic Ark Creation Research outdoor museum fossil and garden site near Gympie in southeast Queensland, Australia. After we found the fossils at this site we deliberately planted living specimens nearby as a testimony to the truth of Genesis, which tells us all plants were created as fully formed organisms according their kinds. The fossil and living trees are identical in structure, so much so they are called “living fossils”. Their abundance in the fossil record worldwide and diminished present day distribution even in Australia is a testimony to the degeneration of the environment that has occurred since Noah’s flood. Australia has dried out and its climate has become subject to more extremes of hot and cold, and Araucarias have been pushed to the limit. Only the fittest have survived, but survival of the fittest is not evolution. (Ref. Botany, conifers, gymnosperms)

Evidence News 26 October 2011

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