The number of days on which increment occurs is the primary determinant of annual ring width in Callitris intratropica
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The number of days on which a measureable increment occurred, and the average rate of stem growth, rather than the overall duration of the wet season, were the main determinants of ring width in young Callitris intratropica trees. These effects were amplified by competition.
Dendroclimatology of tropical tree species is an important tool for understanding past climatic variability at low latitudes where long-term weather records are often absent. Despite the growing number of published tropical tree-ring chronologies, however, still little is known of the factors that control annual ring formation in tropical tree species. In this paper we used an endemic Australian conifer, Callitris intratropica, to study the intra-annual dynamics of seasonal growth and xylem formation, and the effects of environmental conditions and competition, on growth ring formation. We combined high-resolution growth and climate monitoring (every 15 min for 2 years) with less frequent cambial sampling. Trees exhibited marked reductions in growth during certain periods within the rainy season when rainfall was not as regular and VPD was high. Overall, we found that ring width was most influenced by the number of days when increment occurred; regardless of how early the growing season began or ended, and by the rates of tracheid production. The effect of competition was also important. Trees growing in dense groves had narrower annual rings (4.6 mm) than trees that were growing in the open (6.7 mm), due to less active cambia, slower rates of xylem production and expansion and more increment days, although the overall growing season duration was also shorter in grove trees.
KeywordsTropical Dendroclimatology Drought Cambium Xylem Dendrometer Cypress pine Savanna
Thank you to Robert Eager and Jon Schatz based at the Tropical Ecosystem Research Centre in Darwin for help with setting up the instrumentation. Thanks also to Chris Beadle, Jacqui England and anonymous reviewers for many helpful comments and suggestions. This work was funded in part by the Hermon Slade foundation, and the CSIRO office of the Chief executive.
- Bowman DMJS, Wilson BA, Davis GW (1988) Response of Callitris intratropica. In: R.T. Baker, H.G. Smith to fire protection. Australian Journal of Ecology, Murgenella 13: 147–159Google Scholar
- Cook ER (1987) The decomposition of tree-ring series for environmental studies. Tree-ring Bull 47:37–59Google Scholar
- Cook GD, Heerdegen RG (2001) Spatial variation in the duration of the rainy season in monsoonal Australia. Int J Clim 21:1723–1732Google Scholar
- D’Arrigo R, Baker P, Palmer J, Anchukaitis K (2008) Experimental reconstruction of monsoon drought variability for Australasia using tree rings and corals. Geophys Res Lett 35Google Scholar
- Downes GM, Beadle C, Gensler W, Mummery D, Worledge D (1999) Diurnal variation and radial growth of stems in young plantation eucalypts. In: R Wimmer, RE (Eds.) VetterTree ring analysis. Biological, methodological and environmental aspects. CAB International, New York, pp 83–104Google Scholar
- Fritts HC (1976) Tree rings and climate. Academic Press, New York, p 567Google Scholar
- Isbell RF (2002) The Australian Soil Classification. Revised Edition. CSIRO Publishing, MelbourneGoogle Scholar
- Jones PD, Briffa KR, Osborn TJ, Lough JM, van Ommen TD, Vinther BM, Luterbacher J, Wahl ER, Zwiers FW, Mann ME, Schmidt GA, Ammann CM, Buckley BM, Cobb KM, Esper J, Goosse H, Graham N, Jansen E, Kiefer T, Kull C, Kuttel M, Mosley-Thompson E, Overpeck JT, Riedwyl N, Schulz M, Tudhope AW, Villalba R, Wanner H, Wolff E, Xoplaki E (2009) High-resolution palaeoclimatology of the last millennium: a review of current status and future prospects. Holocene 19:3–49CrossRefGoogle Scholar
- McKenzie NJ, Jacquier D, Isbell RF, Brown K (2004) Australian Soils and Landscapes: An Illustrated Compendium. CSIRO Publishing, MelbourneGoogle Scholar
- Skene DS (1969) The period of time taken by cambial derivatives to grow and differentiate into tracheids in Pinus radiata. Ann Bot 33:253–262Google Scholar
- Skene DS (1972) The kinetics of tracheid development in Tsuga canadensis and its relation to tree vigour. Ann Bot 36:179–187Google Scholar