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- 2. Background • Hubbard Brook whole-watershed transpiration response to wollastonite (CaSiO3) addition: mechanisms unclear (Green et al. 2013) • MELNHE wollastonite plots established in 2011 with aim to clarify • Measuring sap flow is one method to estimate transpiration (Granier, 1987)
- 3. Background • Preliminary sap flow measurements from HB Ca suggest increased transpiration in wollastonite treatment (Zahor et al. 2013)
- 4. Research Question • Does a wollastonite addition increase tree transpiration? • Expect that it does, possibly due to increased xylem and fine root growth • Alternatively, sap flow measurements could reflect the transition to decreased transpiration observed in W1 (Green et al. 2013)
- 5. Methods • Sap flow measured by the Granier method: reference probe 10 cm below thermocouple heating probe with constant source of heat, measures temperature difference (ΔT) (Granier, 1987) • Measurements collected by data logger every 30 seconds, average recorded every 15 minutes • ΔT is converted to sapflux (Js, g x m2 x s-1) using BaseLiner software (Oren and Parashkevov, 2012) (Max Planck Institute for Biogeochemistry)
- 6. Methods • Sap flow to be measured in wollastonite and control plots at mature stands in Bartlett Experimental Forest (C8), Hubbard Brook Experimental Forest (Ca) and Jeffers Brook • 9 canopy trees measured per plot: 3 American beech, 3 sugar maple and 3 yellow birch • Measurements collected for ~5 days per stand
- 7. Results 25 20 15 10 5 0 Bartlett C8 171.5 172 172.5 173 173.5 174 174.5 175 175.5 176 176.5 177 Sapflux (Js, g x m2 x s-1) Ordinal Date and Time C8 Control AB C8 Control SM C8 Control YB C8 Ca AB C8 Ca SM C8 Ca YB
- 8. Results 14 12 10 8 6 4 2 0 12:00 AM 4:48 AM 9:36 AM 2:24 PM 7:12 PM 12:00 AM 4:48 AM Sapflux (Js, g x m2 x s-1) C8 Yellow Birch 1 (CaSiO3) YB1 • Example of a representative diurnal curve
- 9. CaSiO3 Control • Within species, more variation across trees than across treatments 25 20 15 10 5 0 12:00 AM 4:48 AM 9:36 AM 2:24 PM 7:12 PM12:00 AM 4:48 AM Sapflux (Js, g x m2 x s-1) C8 American Beech AB1 AB4 AB5 AB6 18 16 14 12 10 8 6 4 2 0 12:00 AM 4:48 AM 9:36 AM 2:24 PM 7:12 PM 12:00 AM4:48 AM Sapflux (Js, g x m2 x s-1) C8 Sugar Maple SM1 SM3 SM4 SM5 SM6 16 14 12 10 8 6 4 2 0 12:00 AM 4:48 AM 9:36 AM 2:24 PM 7:12 PM 12:00 AM 4:48 AM Sapflux (Js, g x m2 x s-1) C8 Yellow Birch YB1 YB2 YB3 YB4 YB5 YB6
- 10. 60 50 40 30 20 10 0 12:00 AM 4:48 AM 9:36 AM 2:24 PM 7:12 PM 12:00 AM4:48 AM Sapflux (Js, g x m2 x s-1) HB Sugar Maple SM2 SM3 SM4 SM5 SM6 25 20 15 10 5 0 12:00 AM 4:48 AM 9:36 AM 2:24 PM 7:12 PM12:00 AM 4:48 AM Sapflux (Js, g x m2 x s-1) HB American Beech AB1 AB3 AB4 AB5 AB6 25 20 15 10 5 0 12:00 AM 4:48 AM 9:36 AM 2:24 PM 7:12 PM 12:00 AM 4:48 AM Sapflux (Js, g x m2 x s-1) HB Yellow Birch YB1 YB3 YB5 YB6 CaSiO3 Control • Within species, more variation across trees than across treatments
- 11. Conclusion • No apparent trends in sapflux between treatments, individual trees highly variable • Solid dataset to work with that will help direct future sap flow efforts
- 12. Future Work • Reevaluate methods: increase sample size and consider additional factors in analysis • Take sap flow measurements from Jeffers Brook, then return to Bartlett C8 and Hubbard Brook for the remainder of the field season • Develop a statistical model to determine significance
- 13. References & Acknowledgements • Granier, A. (1987). Evaluation of transpiration in a Douglas-fir stand by means of sap flow measurements. Tree Physiology 3: 309-320. • Green, M.B., et al. (2013). Decreased water flowing from a forest amended with calcium silicate. Proceedings of the National Academy of Sciences 110(15):5999-6003. • Oren, Parashkevov, & Duke University. (2012). BaseLiner (Version 2.4.2) http://ch2oecology.env.duke.edu/orenlab/sofware.html • Michele Pruyn • Mariann Johnston • Mark Green • Ruth Yanai • Adam Wild, our glorious leader • Shoestring Crew
Notas do Editor
- Picture
- Explain red and blue
- Picture. Green et al graph, wondering about mechanisms, if we’re at the transition stage
- Citation of picture!
- Add Jeffers, plan for rest of the summer.
- Blue lower than red
- Darker and thicker lines . More variation between trees than between treatments. Put all six on one? Let them stare at it while I say: it’s good that we have this continuous data, but now we need to thinking about how to change the methods , if anyone has any ideas for covariates that we should use in analysis
- Darker and thicker lines . More variation between trees than between treatments. Put all six on one? Let them stare at it while I say: it’s good that we have this continuous data, but now we need to thinking about how to change the methods , if anyone has any ideas for covariants that we should use in analysis
- Bring back to Green et al paper, transition, the things Mark talked about
- Normalize by DBH as covariant? Yes, and maybe crown measurements? Maybe focus on only one dominant species in each plot and increase sample size.
- Separate out references and acknowledgements