Tree Planting

Tree planting is considered a best management practice (BMP) for stormwater management. In some respects, trees are the original stormwater BMP, as the gold standard of stormwater management is to reproduce the hydrology of woods in good condition. Trees reduce the quantity and increase the quality of stormwater runoff while also providing many other ecosystem services to our local community.

Stormwater Best Management Practice (BMP) – Stormwater BMPs are strategies for reducing the amount of stormwater runoff or improving the quality of that runoff to reduce or eliminate pollutants reaching local streams and waterways.
Ecosystem services – Ecosystem services are the benefits to humans provided by healthy ecosystems.

  1. How Do Trees Manage Stormwater?
  2. What Other Ecosystem Services Do Trees Provide?
  3. What are the Types of Tree BMPs?

How Do Trees Manage Stormwater?

  1. Trees slow and capture precipitation in their canopy.
      1. More than 20% of annual rainfall is retained by a tree’s canopy.
      2. Some of this precipitation is then evaporated or transpired by the tree. Trees can transpire up to 540 gallons/day.
  2. Precipitation that is not captured in the canopy may be directed down the trunk as “stemflow”
      1. Up to 15% of the precipitation captured by the canopy is directed down the trunk to be intercepted by the soil.
  3. Tree roots and the accumulation of leaf litter under trees promote infiltration of precipitation into the soil.
  4. By reducing the volume and rate of stormwater flowing to local waterways, trees can help to reduce streambank erosion, thereby reducing sediment and pollutants flowing downstream.

Urban Tree Impacts on Hydrology and Water Quality

TreePlantingTaken from Recommendations of the Expert Panel to Define BMP Effectiveness for Urban Tree Canopy Expansion. Chesapeake Bay Program Report CBP/TRS-312-16