Proportion of timber harvest area regenerated by artificial and natural means
Why is this indicator important?
Successful regeneration of harvest areas ensures that forest lands remain productive for wood fibre and continue to provide key ecosystem services such as storing carbon, regulating water quality and quantity, and providing recreation opportunities and wildlife habitat.
In Canada, provincial laws dictate that all harvested areas on provincial Crown lands must be successfully regenerated.
Provinces set standards or have regulations to determine whether a harvest area has been successfully regenerated. These standards vary by province, but commonly incorporate such criteria as: species composition; density and distribution; age and height of the regenerating trees; and distribution of various forest types and age classes across the landscape. Harvested areas must meet provincial regeneration standards in a specified period of time.
Artificial regeneration (planting and seeding) increases the likelihood of achieving regeneration to planned future forest species compositions. It also provides the maximum control of density and stocking.
Natural regeneration can be effective when prescribed for certain conditions and for certain species, such as aspen or lowland spruce. The main benefit of natural regeneration is that it requires minimal human assistance and is therefore potentially less costly than artificial regeneration. However, natural regeneration offers less control over species composition, and remedial measures such as thinning or fill planting may be needed to regulate density and stocking to meet regeneration standards.
The proportion of area regenerated naturally and artificially can fluctuate as a result of several factors, including harvest level, changes in the type of forest harvested, and the amount of area affected by natural disturbances such as fire, insect attack and wind. For example, the amount of burned area from which timber is salvaged can influence annual regeneration rates, since salvage areas may be better suited to natural or to artificial regeneration, depending on the site and original species composition.
Total area regenerated is often correlated with the area harvested, but reported regeneration rates typically lag about two years behind the year of actual disturbance.
What has changed?
Until the early 1950s, foresters managing even-aged forests relied almost exclusively on the natural regeneration of harvested areas. More recently, with improved techniques, better tools and evolving provincial regeneration standards, artificial and natural regeneration each account for approximately half of the total trust area regenerated annually in Canada.
Between 2009 and 2010, the area artificially regenerated increased by 1.8%.1 Conversely, the total number of seedlings planted dropped by 1.0% to a 20-year low of 512 million. Relative to the 10-year average, artificial regeneration area and number of seedlings planted have declined by 10.3 and 13.4%, respectively. However, in 2010, the area of artificial regeneration increased for the first time since the steep decline (42%) in annual harvest area from a 10-year high in 2005 to a 20-year low in 2009.
The reduction in harvest levels began with the onset of a decline in the U.S. housing market and associated reduced demand for Canadian solid wood products. Reduced demand for pulp and paper products has also led to curtailed production in this sector, in turn impacting harvest levels.
The proportion of the area regenerated artificially versus naturally increased in 2010.2 This proportion was estimated at 67.4% of the total harvest area in 2010. This deviation from the historical difference between artificial and natural regeneration may be related to the type of forest harvested. For example, lower demand for hardwood products would lead to fewer hardwood-dominated stands being harvested, and therefore less natural regeneration of these stands. Similarly, a shift in the conifer harvest from lowland to upland sites would necessitate more artificial regeneration.
Total area naturally regenerated is likely to continue to decline until there is a well-established recovery in harvest rates—which itself will rely on improved North American and international demand for Canadian forest products.
|Area (hectares)||Percentage of 2008 harvested areaa||Percentage change in area from previous year||Percentage change in area from 10-year averageb|
|Harvest (2008)a||595 000||-14.0||-31.0|
aAssumes a two-year lag between harvest and regeneration. Harvest area data are from 2008. The portion of 2008 harvested area that is regenerated is calculated by dividing 2010 data by 2008 data.
bThe 10-year average for harvest is for 1998–2007; and the 10-year average for natural and artificial regeneration area is for 2000–2009.
cNatural regeneration = 2008 harvest minus 2010 artificial regeneration.
Source: National Forestry Database
Forest regeneration on provincial Crown lands across Canada, 2000-2010
Source: National Forestry Database
1Data are for even-aged forests on Crown lands across Canada. Federally and privately owned lands are excluded.
2Because there is typically a delay of two years between harvest and regeneration to allow for site preparation and provision of nursery stock, regeneration data from 2010 are compared with harvest data from 2008.
Long description (including data table).
For additional data, visit the National Forestry Database.