Dynamics in Mixed Conifer Forest Southern Sierra Critical Zone

Transcription

1 Southern Sierra CZO Soil Moisture and Tree Water Status Dynamics in Mixed Conifer Forest Southern Sierra Critical Zone Observatory, CA Hartsough 1, P., A. Malazian 1, M. Meadows 2, T. Kamai 1, M. Kandelous 1, E. Eumont 1, K. Roudneva 1, R.C. Bales 2, J.W. Hopmans 1 1) Department of Land, Air and Water Resources, UC Davis 2) Sierra Nevada Research Institute, UC Merced

2 Objectives Monitoring of surface and subsurface water budgets in remote landscapes, with specific attention to moisture and temperature variability in near surface soils Study the interactions between soil hydrology and tree root water uptake in a forested catchment, as part of a wider effort to analyze changing ecosystem response to changing environmental inputs.

3 Location SSCZO Southern Sierra CZO is located at elevations m, across the rain snow transition, in a very productive mixed conifer forest, with extended measurement nodes across various gauged watersheds.

4 Critical Zone Tree 1 White Fir Abies concolor Instrumentation Critical Zone Tree 2 Ponderosa Pine Pinus Ponderosa

5 Summer characterized by dry conditions, soil moisture drawn down by ET Winter characterized by many snowmelt events which enter the soil profile Some as drainage andsome winter ET Flux estimates using sap flow data 20 30cm of Summer ET

6 Spatial patterns of soil water potential at 30cm from the MPS sensors array

7 Spatial patterns of soil water potential at 30cm from the MPS sensors array

8 0 20 cm

9 0 60 cm

10 0 100 cm

11 0 150 cm

12 200 cm

13 Saprolite soil interface

14 Sap rock

15

16 Weathering Sequence with Depth Soil Saprolite Saprock Granitic Bedrock increasing porosity and water holding capacity Deepregolith hold significant amounts ofwater. Saprolite contains little or no clay minerals. Saprock is consolidated and holds original rock fabric.. Solum Saprolite Sap rock Unweathered Granite Courtesy: Ekaterina Roudneva

17 T LiDAR Scanning

18 Raw Scans

19 Root Modeling of LiDAR data Two systems, large roots and small roots Assume axial ilsymmetry Calculate root density, root location relative to the ground surface and various soil horizons Correlate with changes in water content from instrumented tree CZT 1

20 Axial symmetry Tree Hydrology Model ETp 30 m Ta = ETp α F_T Z cm 50 * root buffer region Precipitation X 1.2 m Ra = Rp α F_S 5 m Unit Gradient

21 Modeling Results/Progress Modeling period is June to December no snow

22 Inversemodeling for optimization of model parameters Water stress parameters and tree hydraulic properties (water capacity, hydraulic conductivity) Future Directions 1. Modeling dl

23 NASA soil moisture (SMAP satellite) expand soil moisture monitoring Depth to bedrock Better tools for soil depth assessment Future Directions 2. Upscaling

24 Future Directions 3. Deep monitoring Deep(er) vadose zone monitoring Recharge to/into saprolite and bedrock Continued root measurements Expensive!

25 Acknowledgements NSF, the CZO program Field Crews from UC Davis and UC Merced and UC Irvine Jasper Vrugt, UCI Alison Berry, Berry UCD Carolyn Hunsaker, USFS John Lichter, Tree Associates R Rune St Storesund, d Storesund St d Consulting C lti and many others....

26 Publications Bales, R.C., J.W. Hopmans, T. O Geen, M. Meadows, P.C. Hartsough, P. Kirchner, D. Baudette, C. Hunsaker Soil moisture response to snowmelt and rainfall a Sierra Nevada mixed conifer forest (submitted)) Vadose Zone Journal Malazian, A., Hartsough, P.C., Kamai, T., Campbell, C.S., Cobos, D.R. and Hopmans, J.W. (2011) Evaluation of MPS 1 soil water potential sensor. Journal of Hydrology 402: Nasta, P., Huynh, S., and Hopmans, J.W. (2011) Simplified Multistep Outflow Method to Estimate Unsaturated Hydraulic Functions for Coarse textured Soils. Soil Sci. Soc. Amer. J. 75(2): doi: /sssaj Hunsaker, C.T., Whitaker, T., Bales, R.C. (2010) Water yield and runoff timing across the rain snow transition in California s i southern Sierra Nevada. (Submitted) Kizito, F., Campbell, C.S., Campbell, G.S., Cobos, D.R., Teare, B.L., Carter, B. and Hopmans, J.W. (2008) Frequency, electrical conductivity and temperature analysis of low cost moisture sensor. J. Hydrology 352: DOI: /j.jjhydrol Bales, R.C., M. Conklin, B. Kerkz, S. Glaser, J.W. Hopmans, C. Hunsaker, M. Meadows, P.C. Hartsough, Soil moisture response to snowmelt and rainfall a Sierra Nevada mixed conifer forest In: Levia.D.,et al. (Eds.), Forest Hydrology and Biogeochemistry: Synthesis of Research and Future Directions, 2011 (in press)