The Fireweed complex is one of the most common vegetation communities on logged sites in the southern interior of British Columbia, especially in the ICH, ESSF, and MS zones. It is dominated by fireweed, but minor amounts of grasses and ferns (e.g., lady fern, spiny wood fern, oak fern) can also be present. Shrubs such as thimbleberry, red raspberry, Sitka alder, and willow also occur, especially if several years have passed since harvesting or site preparation. This community occurs across a wide range of environmental conditions, but is most likely to be abundant on mesic or subhygric sites.

Any kind of disturbance that increases light levels and disturbs the forest floor will stimulate development of the Fireweed complex, especially if mineral soil is exposed. For this reason, summer logging is more likely to result in development of a vigorous Fireweed complex than winter-logging. Fireweed is an extremely successful colonizer of newly disturbed sites because it produces abundant seed, and once established, it spreads rapidly by means of vegetative rhizomes. It competes poorly with established vegetation, however, and won’t develop on a site that is already fully occupied by other vegetation. Fireweed abundance usually peaks about 5 years after disturbance and then declines as a canopy of shrubs and conifers develops.

On submesic to mesic sites, the Fireweed complex is not usually vigorous enough to be a serious competitor with young conifer seedlings. This is not the case on subhygric sites, where fireweed can reduce light availability to the point where seedling survival and growth are negatively affected. Vegetation- and snow-press are also a serious risk to seedlings on these sites. On high-elevation sites, a dense Fireweed complex can reduce soil warming. Competition for water and nutrients is not important on the types of sites where fireweed is abundant.