Water budgets of individual local trees

Washington Department of Natural Resources (DNR) is collaborating with Washington State University, City of Tacoma, The Evergreen State College, and Clemson University on a project to measure the effectiveness of local mature forest trees (Phase I study) and younger, smaller trees (Phase II study) to mitigate stormwater runoff in Western Washington. 


Study objectives

The study will answer how much rainfall is managed by an individual tree. It will:

  • Quantify annual transpiration rates and annual canopy interception rates for evergreen and deciduous trees native to the Pacific Northwest.
  • Complete water budget and estimate hydrologic value of existing trees. 

The first phase of the study (Phase I) quantified hydrological benefits of mature trees and Phase II under a new contract agreement targets younger and smaller trees that represents urban trees. 

Project tasks and key deliverables -Phase I (mature forest trees)

Contract IAA & Scope of Work

  1. Project administration
  2. Quality Assurance and Project Protocol development
  3. Instrument purchase and installation
  4. Instrument maintenance and data downloads
  5. Data analysis and QAQC
    • Copy of data: contact SAM staff 
  6. Final Report on Mature Trees and Stormwater Mitigation
  7. Communication & outreach

Project tasks and key deliverables - Phase II (younger smaller trees)

  1. Project Administration 
    • Bioannual reports 
  2. QAPP amendment 
  3. Instrument Installation and moitoring 
  4. Instrument maintenance and downloads 
  5. Data analysis and submittal 
    • Copy of data 
  6. Final Phase II report 
  7. Communication & outreach
    • Presentation
    • Factsheet