Data Sources and Methods for the Sustainability of Timber Harvest Indicator
The Sustainability of Timber Harvest indicator compares wood supply to industrial roundwood harvest.
Wood supply, the volume of timber that may be sustainably harvested, is estimated for each province and territory. Provincial and territorial wood supplies are summed to estimate Canada's wood supply.
Wood supply is the sum of two values:
1. The estimated Annual Allowable Cuts (AACs, known as Allowable Annual Cut in British Columbia) for provincial Crown lands, i.e., publicly owned lands under provincial jurisdiction.
This is the volume of industrial roundwood, as estimated by professional foresters, which may be harvested each year from provincial Crown lands. Provincial Crown lands make up 77% of Canada's forest and other wooded land, but the proportion varies by province (details on forest ownership by province can be found in The State of Canada's Forests Annual Report 2011). Most provinces establish AAC levels for their Crown lands based on a policy of maintaining a non-declining future wood supply and considering a range of additional factors. For example, AAC levels may be decreased in order to maintain animal habitat or increased to permit salvage of insect-damaged wood. The importance of individual factors to the AAC varies among provinces and even among forest management areas within provinces, due to regional differences in forestry policies. The extensive rationale behind an AAC determination for an individual forest management area falls under provincial jurisdiction; additional information may be obtained from provincial resource management organizations.Footnote  The volume of wood harvested may be above or below the AAC in any one year, but needs to balance out over the regulation period. AACs are set based on an assessment of a wide range of ecological, social and economic factors, and are therefore only a proxy for the sustainable level of harvest.
2. Estimates of wood supply on federal, territorial and private lands.
Federal, territorial and private lands account for 2%, 13% and 6%, respectively, of Canada's forest and other wooded land. Wood supply estimates are based on sustainable management plans (when available) or on past harvest levels. Estimation methods are not standardized and may or may not be similar to those used for the AAC.
Because historical harvests are often used to estimate wood supply, recent declines in harvest levels have led to a decreased estimate of wood supply in some jurisdictions. This does not necessarily imply a change in forest health or harvest sustainability.
The 2013 ownership breakdown of wood supply by province and territory is available from the National Forestry Database.Footnote 
Industrial roundwood harvest volumes refer to roundwood, which includes sections of tree stems (with or without bark), logs, bolts, pulpwood, posts and pilings. Industrial fuelwood and household firewood are not usually included as part of the industrial roundwood harvest, although they contribute to the total roundwood harvest. Other forest products such as Christmas trees are not included.
Canada's total industrial roundwood harvest is the sum of the following:
1. The reported industrial roundwood harvested from provincial Crown lands.
Provincial laws require harvest from such lands to be reported and compared to the AAC value for individual forest management areas. Although the harvest must not exceed the AAC over multi-year regulation periods, a deviation by as much as 50% may be allowed in a given year. Regulation periods are 5 to 10 years in most cases.
2. The industrial roundwood harvested from federal, territorial and private lands.
Because there is generally no legislated mechanism to report harvest on these lands, these volumes are estimated by either provincial or federal forest authorities located in that jurisdiction. Harvest from such lands is not regulated, meaning that harvesters are not required by law to compare their harvest to a sustainable level.
The proportion of global forest area in Canada is calculated by dividing the total area of Canada's forests by the world forest area.
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