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Aleza Lake wood ash trial (N and S)

Map of Canada showing the location of the Aleza Lake wood ash research trials in British Columbia.
Location of the Aleza Lake north and south wood ash research trials in British Columbia, Canada.


Central British Columbia
Ecozone: Montane Cordillera
Elevation: 670 m (south site) and 655 m (north site)


1981 to 2010 monthly climate point estimates generated from the Natural Resources Canada climate modeling project.
Mean annual precipitation: 714 mm (north site); 719 mm (south site)
Mean minimum temperature in January: −12.2°C (north and south sites)
Mean maximum temperature in July: 23.1°C (north site); 22.9°C (south site)

Site description

Before the experiment, each site was clearcut (south site: winter 1989 to1990; north site: winter 1996 to1997). The south site was subjected to an intense broadcast burn in September 1990. When the experiment was set up, each site supported a 24-year-old (south site) or 18-year-old (north site) hybrid spruce (Picea engelmannii xglauca) plantation. The soils at both sites developed on glaciolacustrine deposits and have a silty clay loam to clay texture. They are predominantly Luvisols or Luvic Gleysols with a forest floor layer of approximately 5.2 cm.

Ash description

Two ash types were used at the Aleza Lake wood ash trial: (1) ash produced in a gasifier; or (2) ash produced in a boiler. In both cases, the ash feedstock was a mixture of waste wood residues. Only bottom ash was used for the experiment. The ash was not pretreated before application, but the gasifier ash was wetted in October 2014 and stored moist in a covered bin until it was used in May 2015.

A clearcut block within a treed area at the Aleza Lake Research Forest before experimental set-up of a wood ash trial. Photo: Hugues B. Massicotte

A clearcut block at the Aleza Lake Research Forest before experimental set-up of a wood ash trial.

Wood ash being spread using a bucket and shovel on a treed Aleza Lake wood ash trial plot. Photo: Hugues B. Massicotte

Wood ash being spread on an Aleza Lake wood ash trial plot.

Treatment description

In May 2015, six ash and urea treatments were applied using an experimental design to look at both the individual and combined effects of ash applications and urea additions. Treatments included (1) 0 Mg ash per ha, 5 Mg gasifier ash per ha, or 5 Mg boiler ash per ha; and (2) 0 kg urea per ha or 100 kg urea per ha. The quantity of ash applied (Mg per ha) was calculated based on the dry weight of the ash. Ash was applied to the soil surface by hand. The six different treatment types were each replicated three times at both the Aleza Lake north and south sites for a total of 18 plots at each site.


Monitoring treatment effects on trees, understory vegetation, and soil chemistry is ongoing. Data being collected include:

  • Trees
    • Diameter and needle weight
    • Foliar nutrients
  • Understory vegetation
    • Species composition
    • Percent cover
  • Soil chemistry
    • Acidity (pH) and electrical conductivity
    • Total carbon, nitrogen, cations, and trace elements
    • Exchangeable cations
    • Available phosphorus
    • Nitrogen mineralization

Main contact

P. Michael Rutherford, Professor, University of Northern British Columbia


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