The general methodology used for our estimates of forest carbon release associated with each cubic metre of volume cut (as recorded by the Ministry of Forests’ Harvest Billing System) is described here.
That methodology provides us with a simple multiplier for converting the volume of logs taken from a clearcut into an estimate of the total biomass that was killed in that clearcut, which we can then convert to a carbon dioxide-equivalent weight (in metric tonnes).
In short, we multiply the volume harvested as recorded by the Harvest Billing System by 1.64 to determine the carbon-dioxide-equivalent release of emissions.
To determine the emissions associated with a specific clearcut, we determine the volume harvested from that clearcut and multiply by 1.64.
In many cases, however, the volume taken from a specific clearcut is not differentiated from volumes taken from other nearby clearcuts; they are lumped together.
In those cases, to estimate the volume removed from a specific clearcut in a specific tenure requires reference to the Ministry of Forests’ RESULTS database, which provides many points of information about a given clearcut (ID number, area, timber mark) or a group of clearcuts. That information is then correlated with volume information about that clearcut or group of clearcuts in the Harvest Billing System and an average volume per hectare is estimated.
Associated emissions are then based on that average. Since the density of forest biomass varies from stand to stand, these averages may overestimate emissions from the cutting of lower density stands and underestimate emissions from higher density stands.