Indicator: Wood volume
Canada’s forests contain an estimated 45 billion cubic metres of wood. Highly precise inventories of wood volume exist for forests that contribute to timber supply, where it is important to determine sustainable harvest levels. It is also important to monitor general trends in wood volume in all forests for scientific activities such as predicting fire behaviour and carbon accounting. Foresters who undertake forest inventories use a combination of on-the-ground monitoring; monitoring from aircraft with high-precision digital imagery and laser technologies; and monitoring from earth orbiting satellites to collect their data.
Estimated wood volume (million cubic meters) in Canada
- The change in Canadian forest wood volume is the difference between gains from tree growth and losses from tree harvesting and natural mortality.
- Volume losses exceeded volume gains between 1990 and the present because of many factors, especially forest fires and insect outbreaks. 2017 and 2018 were the two worst fire years on record in British Columbia.
What is wood volume?
Foresters may be interested in total wood volume or merchantable wood volume. Merchantable wood volume includes the stem wood of trees of merchantable size, from the top of the stump up to the minimum top diameter. Merchantable size limits, stump heights and top diameters vary depending on the jurisdiction and planned wood use. This indicator reports on total wood volume, which includes the stem wood of trees of all sizes, including the stump and top.
Why is this indicator important?
- Forest wood volume trends are a basic sustainability indicator.
- Wood volume is used along with other information to calculate forest biomass and determine how much carbon is stored in the living trees of Canada’s forests.
What is the outlook?
- Climate change is affecting wood volume trends by influencing tree growth rates, forest fire behaviour and a myriad of other factors. The overall outcome is difficult to predict, but continued wood volume decline is possible.
What reporting frameworks does this indicator support?
- Montreal Process: 2.b
- United Nations Sustainable Development Goals: 188.8.131.52
Sources and information
- Environment and Climate Change Canada. 2020. National Inventory Report 1990–2018: Greenhouse Gas Sources and Sinks in Canada.
- Environment and Climate Change Canada’s National Inventory Report 1990–2018: Greenhouse Gas Sources and Sinks in Canada is based on data and analysis from Natural Resources Canada–Canadian Forest Service’s National Forest Carbon Monitoring, Accounting and Reporting System.
- Kurz, W.A., Dymond, C.C., et al. 2009. CBM-CFS3: A model of carbon-dynamics in forestry and land-use change implementing IPCC standards. Ecological Modelling 220, 480–504.
- National Forest Inventory. Standard reports, Table 15.0. Total tree volume (million m3) on forest land by forest type and age class in Canada. (accessed March 27, 2020)
- Baseline estimate of Canada’s wood volume.
Methodology used to adjust baseline estimates of wood volume:
Canada’s National Forest Inventory (NFI) is completing the data processing, quality control, compilation and estimation for its first re-measurement cycle (2008 to 2017). Canada is therefore in a position to report national wood volume estimates for only one period using NFI data. NFI baseline data were collected from 2000 to 2006, and the wood volume estimate based on these data is reported here in the 2000 reporting year.
Forecasting and backcasting from 2000 was done using above-ground biomass carbon stock estimates from Canada's National Forest Carbon Monitoring Accounting and Reporting System (NFCMARS), NIR 2020 version. Changes in wood volume should be closely related to changes in above-ground forest biomass and above-ground forest biomass carbon. Wood volume in 2000 was used to calculate wood volume in all other reporting years using the change in above-ground biomass carbon stock relative to 2000, as follows:
- Wood volume in [year] = (wood volume in 2000) x (above-ground biomass in [year] / above-ground biomass in 2000)
- Wood volume data are typically used to derive above-ground biomass and carbon data, but the opposite was done here because the NFI has only one complete measurement cycle whereas NFCMARS has a complete time series from 1990 to 2017.
- In NFCMARS, the Carbon Budget Model of the Canadian Forest Sector (CBM-CFS3) uses merchantable wood volume growth increment data and converts these to biomass and then carbon. However, this all happens internally in the model, and CBM-CFS3 outputs are all in units of carbon (CBM-CFS3: a model of carbon-dynamics in forestry and land-use change implementing IPCC standards. 2009. Kurz, W., et al.).
- Note that NFCMARS does not provide data for all of Canada's forests. It is assumed here that the above-ground biomass carbon stock trend in Canada's managed forests is a good predictor of wood volume trend for Canada's entire forest (managed and unmanaged).
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