The Aspen complex is characterized by relatively pure stands of trembling aspen, but paper birch and black cottonwood may be present in lesser quantities. On sites where birch and/or cottonwood are at least as abundant as aspen, the community is classified as the Mixed Broadleaf-Shrub complex. Common understorey species associated with the Aspen complex are fireweed, pinegrass, and thimbleberry. The Aspen complex occurs throughout the IDF, MS, and ICH zones of southern interior British Columbia. Aspen is common across a range of moisture and nutrient regimes, but is most productive on fresh to moist, well-drained, nutrient-rich sites. In the southern interior, aspen typically grows to about 3 m tall by age 8.

Aspen reproduces primarily by suckering from parent trees. Sucker initiation and growth are promoted by high light levels and warm soils, so clearcut logging, and site preparation treatments that expose mineral soil (e.g., scarification and severe broadcast burns), stimulate development of the Aspen complex. Treatments that break up the root system, such as deep ploughing, tend to reduce suckering. Aspen regeneration from seed is uncommon.

Aspen can benefit conifers by taking up large amounts of nutrients and thus retaining them in the ecosystem, by slowing the spread of root diseases, by reducing frost damage, and by increasing windfirmness of neighbouring conifers. However, at high density and basal area, aspen can reduce light and soil moisture to levels that are limiting to conifer growth for at least part of the growing season.

Typical development of the Aspen complex 7 years after disturbance.