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Up and Down : A Tale of the Over- and Understorey at EucFACE

Remko Duursma
November 10, 2017

Up and Down : A Tale of the Over- and Understorey at EucFACE

Analysis of light intensity timeseries and photos to describe the greening up and browning of a Eucalyptus forest.

Remko Duursma

November 10, 2017
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  1. UP AND DOWN: A TALE OF THE UNDER- AND OVERSTOREY

    AT EUCFACE Duursma 23/10/2017 1 Remko Duursma and co-authors
  2. VEGETATION RESPONSE TO CLIMATE CHANGE: FUNCTION VS. STRUCTURE • Elevated

    CO2 stimulates leaf photosynthesis • Is this extra carbon is used to grow more leaves (in the canopy or in the understorey)? 2 CO2 ↑ Forest C uptake ↑ Forest leaf area ↑ Even more uptake?
  3. THE EARTH IS GREENING UP – DUE TO CO2 ?

    • Some more text here • Text 3 Zhu et al. 2016, Nature Climate Change
  4. Duursma 23/10/2017 4 • Diversity plots Tree canopy: - increased

    leaf growth in eCO2 ? - change in greenness? Understorey: - change in species composition? - change in greenness?
  5. DO FORESTS HAVE A HIGHER LEAF AREA UNDER ELEVATED CO2

    ? • Previous forest FACE experiments have shown a response, sometimes… Duursma 23/10/2017 6 Leaf area index response to eCO2 Leaf area index (control plots)
  6. CANOPY MONITORING: LEAF AREA INDEX FROM CANOPY TRANSMITTANCE • 3

    sensors below canopy in each FACE ring, one above (each ring) • Estimate LAI from transmittance (below canopy / above canopy PAR) Canopy leaf area of a mature evergreen Eucalyptus woodland does not respond to elevated atmospheric [CO2 ] but tracks water availability Remko Duursma, T. Gimeno, M. Boer, K. Crous, M. Tjoelker, D. Ellsworth Global Change Biology, 2016
  7. 9 View from Ring 1, 18 Oct. 2017. WHAT ABOUT

    GREENNESS? AN UNEXPECTED USE OF SECURITY CAMERAS AT THE EUCFACE
  8. • The cameras are programmed to take six photos of

    each ring, 3 times a day • More than 130,000 photos since Nov . 2014 • Analyze images for 'greenness', as G / (R+G+B) • Greenness = Amount of leaves x Colour of leaves
  9. Duursma 23/10/2017 14 • Expect C3 plants to do better!

    • C4 plants have a CO2 concentrating mechanism, so increasing [CO2 ] has little effect • C3 plants evolved during times when [CO2 ] was high Review of previous FACE data; Ainsworth and Long (2007) ELEVATED CO2 : EXPECTED WINNERS AND LOSERS?
  10. Elevated CO2 concentrations reduce C4 abundance and decrease diversity of

    understorey plant community in a Eucalyptus woodland Shun Hasegawa, J. Piñeiro, R. Ochoa-Hueso, A. Haigh, P. Rymer, K. Barnett, S. Power in review ELEVATED CO2 : C4 SPECIES DECLINE, DOMINANT SPECIES WIN
  11. 17 Elevated [CO2 ] does not increase understorey productivity during

    periods of low water availability in a temperate grassy woodland Luke Collins, R. Bradstock, V. Resco de Dios, R. Duursma, S. Velasco, M. Boer in review Custom software analyzes average greenness of the pixels over a 'region of interest' 'Phenocam', a simple camera takes photos every day before sunrise
  12. 20 MAKING THE MOST OF (LOTS OF) DATA I showed

    the result of • 115 thousand photos of the canopy, 35 thousand photos of the understorey • 18 understorey light sensors, 6 above-canopy light sensors, combined 62 million observations of light intensity …and more
  13. 21 • To better understand canopy dynamics of evergreen Eucalyptus

    woodlands, we need longer timeseries • To inform larger-scale vegetation assessments, comparison with remote sensing methods is underway • Change in species composition over time – is it persistent or transitory? WHAT'S NEXT?
  14. THANKS TO Co-authors and collaborators Shun Hasegawa, Juan Piñeiro, Sally

    Power, Matthias Boer, Luke Collins, Belinda Medlyn, Mark Tjoelker, Teresa Gimeno, David Ellsworth, Kristine Crous, Paul Rymer, John Drake, and others. Technical Support Gerard Devine, Craig McNamara, Vinod Kumar, Craig Barton, Steve Wohl