Sitka alder is the dominant species of the Dry Alder complex, but willow is also present on some sites, along with thimbleberry in the understorey. Characteristic herbs associated with this community are fireweed on mesic and wetter sites and pinegrass where conditions are drier than mesic. In southern interior British Columbia, the Dry Alder complex occurs throughout the MS biogeoclimatic zone, and is somewhat less common in the ICH, SBS, upper IDF, and lower ESSF zones. It occurs predominantly on north and east aspects and on submesic to subhygric sites. It tolerates a range of soil and parent materials, but is most common on moderately-well- to well-drained, coarse- to loamy-textured Brunisols and Luvisols.

Sitka alder is often present under mature lodgepole pine forests in southern interior B.C., but because it is only moderately shade tolerant, it does not grow vigorously until light is increased following logging. Ground disturbance during logging, mechanical site preparation, and burning enhance alder abundance by providing a favourable seedbed and by stimulating sprouting from existing root crowns. Practices that hinder development of the complex include severe fire or mechanical site preparation treatments that destroy roots. Sitka alder grows faster when it originates from cut stems than seed, but regardless of origin, growth slows with age of the plants. Young alder grows 20-120 cm/year, depending on the origin of the plants and site quality, whereas typical height growth by age 10-15 years is 10-20 cm/year.

The Dry Alder complex is not usually a serious competitor with conifers if seedlings are established soon after logging. On most sites, extensive areas of continuous alder do not develop. Rather, multi-stemmed clumps of alder are interspersed with open areas, with conifer seedlings becoming established between, not under, the alder bushes. The presence of some alder can increase nutrient availability through nitrogen fixation and the annual shedding of foliage.

The Dry Alder complex 14 years after logging.