Skip to main content Skip to navigation

Biomass Productivity

Testing Ways to Improve Poplar Biomass Productivity


We are working to maximize poplar biomass productivity by improving poplar farming techniques using three different approaches:

  1. First, we are exploring different poplar planting densities of 1,089, 1,452 and 2,178 trees per acre.
  2. In a second investigation, we are interplanting poplar with alder to see if alder’s nitrogen-fixing ability improves poplar yield.
  3. Third we are comparing the difference in poplar regrowth and productivity when harvested in the winter versus the late summer.


Refining biomass production techniques will have a range of impacts including widening the period of time that plantations can be harvested throughout the year and ensuring that plantation stocking rates are appropriate for the harvest rotation length. Improved production methods will allow the process to be economically viable at a commercial scale.


Field trials were established at the Jefferson and Hayden sites in 2012 and at Pilchuck and Clarksburg in 2013. Each site has replicated factorial experiments to test the effects of planting density and interplanting with alder. The 2012 trials have established well with high survival and good growth. First year data will be collected from the 2013 trials later this year.

Worker uses a measuring stick to record the height of a poplar tree.
Jose Zerpa of GWR measuring heights at the Jefferson, OR demonstration site.