Pre-CanLaD v2: Canadian Forest Disturbance History 1950-1984 at 30-m Resolution

Four raster layers document forest disturbances from 1950 to 1984 across Canada at 30-meter resolution. The dataset, updated by Natural Resources Canada in 2026, identifies disturbance types (fire, harvest, insect) and years using a dual detection approach combining automated classification and manual photo-interpretation. It integrates sources like the National Burn Area Composite to improve fire year attribution.

Use Cases

• Mapping historical fire perimeters and harvest areas based on the disturbance type and year raster layers.
• Studying forest regeneration patterns by analyzing post-1985 vegetation cover differences referenced in the methodology.
• Assessing data provenance and version changes for specific pixels using the correction and update mask layers.
• Mitigating temporal uncertainty in disturbance models by grouping disturbance years into age classes as suggested in the limitations.

Strengths

• Provides a 35-year historical record (1950-1984) of forest disturbances.
• Uses a dual detection method combining automated polygon-based classification with manual photo-interpretation.
• Integrates external authoritative data sources like the National Burn Area Composite (1972-1984) for improved fire attribution.
• Includes a provenance mask detailing data source corrections (e.g., CNFDB-corrected fire, NBAC-corrected fire).

Limitations

• Temporal uncertainty remains; some disturbance years may be approximate.
• Detection is biased toward high-severity burns and may miss low-severity fires or those in non-forested areas.
• Harvest detection relies on provincial forest inventories, creating a potential bias toward provinces with publicly available data.
• Description metadata is limited; actual data quality and spatial coverage require manual inspection after download.

Provenance

Source

Natural Resources Canada

Collection Method

Fractional land-cover change analysis (1985-2020), combined automated polygon-based classification and manual photo-interpretation, integrated with NBAC and CNFDB fire perimeters.

Time Range

1950-1984

Freshness

Last updated 2026-04-22.

Geography

Canada