H14D-02: Root Phenology at Harvard Forest and Beyond. Rose Abramoff, Adrien Finzi Boston University

Transcription

1 H14D-02: Root Phenology at Harvard Forest and Beyond Rose Abramoff, Adrien Finzi Boston University

2 satimagingcorp.com Aboveground phenology = big data

3 Model Aboveground Phenology Belowground Phenology C allocation TRIFFID Temperature n/a Allometric equations and partitioning into spreading and growth based on LAI Citation Cox 2001 Hyland n/a n/a Allometric equations Friend et al. 1997, Friend and White 2000, Levy et al PnET-BGC ORCHIDEE IBIS Temperature GDD Temperature and soil moisture GDD Temperature Productivity threshold Monthly turnover rate Fixed site-specific ratios Kram et al n/a Resource optimization Krinner et al n/a Fixed annually for leaf:stem:root Mcguire et al TEM Evapotranspiration n/a Not explicit Mcguire et al ED2 Logistic functions derived from MODIS data n/a PFT-dependent allocation relationships, root:leaf allocation determined by optimization Medvigy et al CLM 4.0 GDD Temperature and soil moisture Daylength n/a Allometic equation based on fixed ratios of fine root:leaf and coarse root:stem Oleson et al. 2009, Thornton and Zimmerman 2007 LPJ BIOME-BGC GDD Temperature and soil moisture Optimized from satellite observation n/a Allometric equations Sitch et al n/a Allometric equations White et al Sheffield- DGVM Temperature and soil moisture n/a Based on demand by different plant organs LAI>roots>wood Woodward et al. 1995, Woodward and Lomas 2004 Abramoff and Finzi (in prep)

4 Model Aboveground Phenology Belowground Phenology C allocation TRIFFID Temperature n/a Allometric equations and partitioning into spreading and growth based on LAI Citation Cox 2001 Hyland n/a n/a Allometric equations Friend et al. 1997, Friend and White 2000, Levy et al PnET-BGC ORCHIDEE IBIS Temperature GDD Temperature and soil moisture GDD Temperature Productivity threshold Monthly turnover rate Fixed site-specific ratios Kram et al n/a Resource optimization Krinner et al n/a Fixed annually for leaf:stem:root Mcguire et al TEM Evapotranspiration n/a Not explicit Mcguire et al ED2 Logistic functions derived from MODIS data n/a PFT-dependent allocation relationships, root:leaf allocation determined by optimization Medvigy et al CLM 4.0 GDD Temperature and soil moisture Daylength n/a Allometic equation based on fixed ratios of fine root:leaf and coarse root:stem Oleson et al. 2009, Thornton and Zimmerman 2007 LPJ BIOME-BGC GDD Temperature and soil moisture Optimized from satellite observation n/a Allometric equations Sitch et al n/a Allometric equations White et al Sheffield- DGVM Temperature and soil moisture n/a Based on demand by different plant organs LAI>roots>wood Woodward et al. 1995, Woodward and Lomas 2004 Abramoff and Finzi (in prep)

5 Objectives Can aboveground phenology predict belowground phenology? 1) On a biome scale? 2) On a local scale? How does the magnitude of C allocated to roots differ across the season and between species?

6 Objectives Can aboveground phenology predict belowground phenology? 1) On a biome scale? 2) On a local scale? How does the magnitude of C allocated to roots differ across the season and between species?

7 1) N=47 2) 15 studies 37 species 3) 4 biomes Boreal Temperate Mediterranean Subtropical Shoot methods Direct observation Root methods Soil coring or excavation Minirhizotron camera Field rhizotron or root box Soil CO 2 efflux

8 (offset = DOY peak root DOY peak shoot ) Herbaceous Woody Offset (day)

9 Hypothesized response of offset to environmental variables Cold soils => relatively later root growth

10 Hypothesized response of offset to environmental variables Cold soils => relatively later root growth Dry soils => relatively earlier root growth

11 Temperature Offset (day) Boreal Mediterranean Subtropical Temperate Median annual air temperature (deg C)

12 Precipitation Offset (day) Boreal Mediterranean Subtropical Temperate Mean annual precipitation (mm)

13 Grouped by biome a Offset (day) ab bc c Boreal Temperate Mediterranean Subtropical Biome type

14 Grouped by physiology a Offset (day) b 20 0 Evergreen Tree type Deciduous

15 Grouped by biome a Offset (day) ab bc c Boreal Temperate Mediterranean Subtropical Biome type

16 Grouped by biome a Offset (day) ab bc c Boreal Temperate Mediterranean Subtropical Biome type

17 Objectives Can aboveground phenology predict belowground phenology? 1) On a biome scale? 2) On a local scale? How does the magnitude of C allocated to roots differ across the season and between species?

18 NEON Inc.

19 (Migliavacca et al. 2011) Shoot methods Phenocam network (GCC= G/[R + G + B]) Root methods Minirhizotron camera Species AM/EM Deciduous/Evergreen White ash (Fraxinus americana) AM Deciduous Red oak (Quercus rubra) EM Deciduous Eastern hemlock (Tsuga canadensis) EM Evergreen

20 Red oak root growth Fine root growth (g root * day -1 * tube -1 ) Day of year Offset = 27

21 Red oak root growth Fine root growth (g root * day -1 * tube -1 ) Day of year Offset = 27 Offset 2012 = 11

22 Eastern hemlock root growth Fine root growth (g root * day -1 * tube -1 ) Day of year Offset = 100

23 Eastern hemlock root growth Fine root growth (g root * day -1 * tube -1 ) Day of year Offset = 100 Offset 2012 = 89

24 White ash root growth Fine root growth (g root * day -1 * tube -1 ) Day of year Offset = 33

25 Offset (day) a ab bc c HF average offset = Boreal Temperate Mediterranean Subtropical Biome type

26 a Hemlock offset Offset (day) b Ash offset 0 Evergreen Tree type Deciduous Oak offset

27 Objectives Can aboveground phenology predict belowground phenology? 1) On a biome scale? 2) On a local scale? How does the magnitude of C allocated to roots differ across the season and between species?

28 Biomass accumulation Fine root biomass gross accumulation (g root* tube -1 ) /1/2012 8/1/ /1/2012 4/1/2013 8/1/ /1/2013 White ash Red oak Eastern hemlock Date Oak Ash Hemlock

29 Fine root production and turnover time Species BNPP (gcm -2 ) BGPP (gcm -2 ) Net Turnover Time (years) Oak Hemlock Gross Turnover Time (years) Ash

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31 To the root of the matter Can aboveground phenology predict belowground phenology? 1) On a biome scale? More data may reveal biome-level relationships between above and belowground phenology 2) On a local scale? Deciduous oak and ash are relatively more synchronous than evergreen hemlock How does the magnitude of C allocated to roots differ across the season and between species? Oak and ash allocate more C to root growth earlier in the season than hemlock Oak and ash allocate a greater magnitude of C to root growth than hemlock Oak allocates relatively less GPP to fine root respiration than do hemlock and ash, while hemlock allocates relatively more GPP to exudation.

32 Growth and metabolism Growth and metabolism Growth and metabolism Growth and metabolism Phenology feeds back into the C cycle Roots Microbes Warm, wet Warm, wet Annual C efflux from soils Growing season Growing season Cold Dry Cold Dry Annual C efflux from soils Growing season Growing season

33 Acknowledgements Abramoff, R.A., Finzi, A.C. Root phenology: environmental and endogenous drivers. (in prep) Migliavacca, Mirco, et al. "Using digital repeat photography and eddy covariance data to model grassland phenology and photosynthetic CO2 uptake." Agricultural and forest meteorology (2011): Richardson, A. D., Braswell, B.H, Friedl, M.A, Hollinger D.Y., Ollinger S.V., Milliman T PhenoCam. URL:phenocam.sr.unh.edu/webcam/