Spatial and Temporal Patterns of Forest Fires in North America as Determined from 12 Years of Daily AVHRR Data

Fires in boreal and temperate forests play a significant role in the global carbon cycle. While forest fires in North America (NA) have been surveyed most extensively by US and Canadian forest services, most fire records are limited seasonal statistics without information on temporal evolution and spatial expansion, although such information is crucial for modeling fire emissions. Using the daily Advanced Very High Resolution Radiometer (AVHRR) data archived from 1989 to 2000, we have obtained an extensive and coherent fire products across the entire NA forest regions on a daily basis at 1-km resolution. The product was generated following data calibration, geo-referencing, application of an active fire detection algorithm modified based on Li et al. (2000a), and a fire mapping algorithm: the HANDS (Hotspot and NDVI Differencing Synergy) (Fraser et al., 2000). The spatial-temporal variations of forest fires in NA are analyzed in terms of (1) annual and monthly patterns of fire occurrences in three eco-domains, (2) the influence of topographic conditions (elevation zones, aspect classes and slope classes), (3) differences among major forest types and eco-regions in NA. It was found that 1) among the 12 years (1989-2000), 1989 and 1995 are the most severe fire years in NA; 2) the majority of burning occurred in July and Jun and in lower elevation zones (< 500 m) with gentle slopes (< 10 deg), except in the dry eco-domain where more fires occurred in higher elevation zones (> 2000 m); 3) most fires occurred in the polar eco-domain, the subarctic eco-division and in the tayga (boreal forests), forest-tundras and open woodlands eco-provinces in the boreal forests of Canada. The higher elevation zone (>1500 m) with steeper slope class (> 15 deg) is apt to multi-burning events happening during the 12 years.