The changing disturbance regime of the boreal forest of the Canadian Prairie Provinces
Document Type: Journal Article
Author(s): K. P. Timoney
Publication Year: 2003

Cataloging Information

  • age classes
  • agriculture
  • biomass
  • boreal forests
  • British Columbia
  • Canada
  • coniferous forests
  • deciduous forests
  • defoliation
  • disturbance
  • ecosystem
  • ecosystem dynamics
  • fire frequency
  • fire management
  • fire size
  • foliage
  • forest fragmentation
  • forest management
  • grasses
  • insects
  • landscape ecology
  • logging
  • logging
  • Manitoba
  • perturbation
  • petroleum
  • plant diseases
  • plantations
  • prescribed fires (escaped)
  • Saskatchewan
  • soils
  • vegetation
  • vegetation surveys
  • water
  • wildfires
Record Maintained By:
Record Last Modified: June 1, 2018
FRAMES Record Number: 45149
Tall Timbers Record Number: 20617
TTRS Location Status: In-file
TTRS Call Number: Fire File
TTRS Abstract Status: Okay, Fair use, Reproduced by permission

This bibliographic record was either created or modified by the Tall Timbers Research Station and Land Conservancy and is provided without charge to promote research and education in Fire Ecology. The E.V. Komarek Fire Ecology Database is the intellectual property of the Tall Timbers Research Station and Land Conservancy.


The subhumid boreal forest of western Canada is different today from what it was 25 years ago. Before the 1950s, the main human impacts on this forest were agricultural expansion, escaped settlement fires, and high-grade logging. The latter half of the 20th Century saw increased human stresses placed on the ecosystems, against a background of insect outbreaks and high forest fire activity. In the Prairie provinces, current annual area burned is greater and more variable than it was in the 1970s. Over the past 25 years, the area disturbed by insects (primarily forest tent caterpillar) and disease has declined, but both the area and timber volume logged have risen. The boreal forest (particularly its southern half) is being converted to a fragmented landscape dominated by young aspen, shrub, grass, plantations, exotic species, industrial infrastructure, and agricultural fields. The current disturbance level has increased to the point that forest land and volume losses now exceed forest accruals in some regions; average forest age and biomass have been declining since about 1970. Relative to past decades, the present subhumid boreal forest region of Canada is warmer, and more fragmented and dissected; it supports less old growth, less old white spruce, and more young aspen and recently disturbed areas; it has simplified and truncated age-class structures; and it has a greater prevalence of non-native plants. Future stresses may include in situ tar sands development, groundwater depletion or degradation, and water diversions. Should present trends continue, declining forest productivity and predictability, and spread of exotic species are likely, as is replacement of coniferous forest by deciduous forest in some regions. Stressed aquatic systems may undergo major changes in biotic composition, productivity, and physical characteristics. Without a rapid decrease in the rate of disturbances, the establishment of a more complete protected areas network, and the adoption of ecosystem-centred management, the subhumid boreal ecosystem will continue to be degraded. © The Canadian Institute of Forestry/Institut forestier du Canada. Abstract reproduced by permission.

Online Link(s):
Timoney, K. P. 2003. The changing disturbance regime of the boreal forest of the Canadian Prairie Provinces. Forestry Chronicle, v. 79, no. 3, p. 502-516.