Developing annual tree-ring chronologies and climate reconstructions from moisture sensitive Araucariaceae trees in tropical and subtropical Australia
No Thumbnail Available
Date
2019-07-30
Journal Title
Journal ISSN
Volume Title
Publisher
International Union for Quaternary Research (INQUA)
Abstract
Many parts of tropical and subtropical Australia lack both annually-resolved long-term instrumental climate data and proxy climate records. This limits our understanding of past climate patterns and impacts. There are however, remnant forest stands where dendroclimatology could be applied to extend the climate record. Early studies into tropical Australian tree species suggested difficulty in dating these records due to the fact they are compromised by numerous ring anomalies. This has led to such species being understudied with little known about their tree growth to climate relationships and paleoclimate potential. Recent research of trees in the Araucariaceae family has attempted to address these issues in order to develop annual, chronologically precise, long-term climate reconstructions across tropical and subtropical Australia.
Araucariaceae trees are commonly found across northern and eastern Australia and are longer lived than many other local non-temperate species. They are known to produce growth rings that are mostly annual and their growth appears sensitive to climate, specifically to moisture conditions. Three Araucariaceae species, hoop pine (Araucaria cunninghamii), bunya pine (Araucaria bidwillii) and purple kauri pine (Agathis atropurpurea) have been studied at five locations within the rainforests of eastern Queensland. Ring anomalies including false, faint, locally absent, and pinching or wedging rings, were identified. This was done by applying bomb-pulse radiocarbon dating, radiographic analysis, and density pattern assessment to hoop pine trees from subtropical Lamington and D’Aguilar National Parks. Additionally, dendrometers were installed on trees of all three species so that the annual nature of growth could be proven and the climate variables influencing seasonal growth identified. This analysis verified annual growth for all three species and proved that dating can be confirmed using a multi-technique approach. This demonstrates the suitability for dendrochronology in tropical and subtropical Australia to be applied for high-resolution climate reconstruction. Examination of growth-climate relationships indicated that moisture conditions are driving tree growth in these species so long-term reconstructions of rainfall and drought can be established. Following this, a 164-year drought reconstruction for Southeast Queensland was developed using hoop pine trees from the subtropical rainforest of Lamington National Park and a record extending back to 1400 has been developed for tropical Queensland. Additional work is continuing using this approach to further develop a network of long-term Queensland, Australia tree-ring climate records.
Description
Keywords
Tree rings, Climate models, Moisture, Trees, Australia, Tropical regions, Forests, Climatic change, Queensland, Climates
Citation
Haines, H. A., English, N. B., Hua, Q., Olley, J. M., Gadd, P. S., Palmer, J. G., & Kemp, J. (2018). Developing annual tree-ring chronologies and climate reconstructions from moisture sensitive Araucariaceae trees in tropical and subtropical Australia. Paper presented at the 20th INQUA Congress 25th - 31st July 2019, Dublin, Ireland. Retrieved from: https://virtual.oxfordabstracts.com/#/event/public/574/submission/1607