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SUMMARY:Soil Moisture and Tree Water Status Dynamics in Mixed-Conifer Fore
 st Southern Sierra Critical Zone Observatory\, CA 
DTSTART:20110920T161500
DTSTAMP:20260511T050456Z
UID:350145c362420623c957b8c1ac04023201fc01cf02f5346bae1cc3a7
CATEGORIES:Conferences - Seminars
DESCRIPTION:Dr Jan Hopmans\, Dept of Land\, Air and Water Resources\, Univ
 ersity of California Davis\, USA\nThe presentation will show the results o
 f a multi-year deployment of soil moisture sensors to study the hydrologic
 / biotic interactions in a mixed-conifer forest at an elevation of ~2000m 
 in the Southern Sierra Critical Zone Observatory (CZO). To better understa
 nd root-soil water interactions in a multi-dimensional soil/vegetation sys
 tem\, a mature white fir (Abies concolor) and the surrounding root zone  w
 as continuously monitored (sap-flow\, canopy stem-water-potential\, soil m
 oisture\, soil water potential and temperature)\, to characterize the hydr
 aulics across the soil-root-tree-atmosphere continuum (SPAC) for this sing
 le tree.   The additional deployment of more than 250 sensors to measure t
 emperature\, volumetric water content\, soil water matric potential\, and 
 snow depth  across the watershed  complements trunk sap-flow and canopy st
 em-water-potential measurements.  Uncertainty exists in the depth from whi
 ch tree roots extract soil water\, specifically related to the presence of
  underlying saprolite/ bedrock\, and the role of deep moisture storage.  T
 o better characterize processes in the subsurface\, we excavated the root 
 system of a nearby mature white fir\, using compressed air to remove the s
 oil surrounding the tree roots.  This method left the roots intact and ena
 bled quantification of root density with depth in addition to in situ root
  architecture.  The roots were imaged using a Terrestrial LiDAR system to 
 build a 3-D model of root size and density relative to presence of soil ho
 rizons.  LiDAR images allowed us to also determine tree root volume and ot
 her related root characteristics.  The results from this experiment are pa
 rt of an ongoing computer modeling study to test assumptions about tree ro
 ot water  uptake\, compensated root water uptake\, and to analyze soil wat
 er stress effects on tree water hydraulics and tree canopy transpiration.
LOCATION:GR C0 01
STATUS:CONFIRMED
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