sophie harrison sap flow reucon
Post on 04-Jul-2015
122 Views
Preview:
DESCRIPTION
TRANSCRIPT
Background
• Hubbard Brook whole-watershed transpiration response to wollastonite (CaSiO3) addition
(Green et al. 2013)
Background
• Measuring sap flow is one method to estimate transpiration (Granier, 1987)
• Taking sap flow measurements at MELNHE wollastonite plots could help clarify mechanisms underlying HB W1 transpiration response
• Preliminary sap flow measurements from HB Ca suggest increased transpiration in wollastonitetreatment (Zahor et al. 2013)
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)
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 converted to sapflux (Js, g x m2 x s-1) using BaseLiner software (Oren and Parashkevov, 2012)
(Max Planck Institute for Biogeochemistry)
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
Results
0
5
10
15
20
25
171.5 172 172.5 173 173.5 174 174.5 175 175.5 176 176.5 177
Sap
flu
x (J
s, g
x m
2 x
s-1
)
Ordinal Date and Time
Bartlett C8
C8 Control AB
C8 Control SM
C8 Control YB
C8 Ca AB
C8 Ca SM
C8 Ca YB
Results- Bartlett C8
Results- Bartlett C8
Results- Bartlett C8
Results- Hubbard Brook
Results- Hubbard Brook
Results- Hubbard Brook
Changes to Methods
• To increase statistical power, decided to measure 5 sugar maple and 5 yellow birch trees per plot at Jeffers Brook
Results- Jeffers Brook
Results- Jeffers Brook
Results- Jeffers Brook
Results- Jeffers Brook
Conclusion
• Data suggests increased sap flow in Bartlett C8 and Jeffers Brook, but decreased sap flow in Hubbard Brook
• Statistical analysis
• Consider additional covariates and research questions moving forward, why is Hubbard Brook different?
• Continuous dataset to work with!
• Step toward understanding how CaSiO3 impacts forest health and hydrology amidst acid rain, could influence management techniques
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 Sciences110(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
top related