Greater Vancouver, British Columbia, Canada has a cool, humid, mesothermal climate. It has cloudy, wet, and mild winters and sunny, dry, and warm summers (Weber 1972, Meidinger and Pojar 1991). Mean daily temperature values recorded during the study period ranged from 14.2° and 19.0°C and were just slightly above normal mean daily temperatures for June–September. Precipitation means were also near normal levels (72–108 mm at higher elevations and 40–76 mm at lower elevations). The study area ranged in elevation from sea level to 370 m.

The Georgia Basin lies almost entirely within the Coastal Western Hemlock (CWH) biogeoclimatic zone (Green and Klinka 1994). The original vegetation of the area would have resembled a dense coniferous forest, with a shrub-dominated understory. The climax vegetation of the CWH zone is generally dominated by a canopy of western redcedar (Thuja plicata) and western hemlock (Tsuga heterophylla), with Douglas-fir (Pseudotsuga menziesii) in drier areas and minor amounts of sitka spruce (Picea sitchensis), yellow-cedar (Chamaecyparis nootkatensis), and lodgepole pine (Pinus contorta). The most prominent species of the original understory vegetation are salal (Gaultheria shallon), Alaskan blueberry (Vaccinium alaskaense), false azalea (Menziesia ferruginea), and red huckleberry (Vaccinium parvifolium), with salmonberry (Rubus spectabilis) and red elderberry (Sambucus racemosa) found on wetter sites. The supplanted herb and dense moss layers are composed of deer fern (Blechnum spicant), bunchberry (Cornus canadensis), and false-lily-of-the-valley (Maianthemum dilatatum), step moss (Hylocomium splendens), lanky moss (Rhytidiadelphus loreus), and Oregon beaked moss (Kindbergia oregana) (Weber 1972, Meidinger and Pojar 1991, Demarchi 1996). Pacific Spirit, Stanley, and Central Park, Vancouver, and Burnaby Regional Parks are relatively large areas within this urban context that still contain representative vegetation of the CWH zone; these parks also contain many species of non-native vegetation, such as English holly (Ilex aquifolium) and Himalayan blackberry (Rubus discolor). Botanical nomenclature follows Pojar and Mackinnon (1994) for vascular plants and Little (1980) for woody plants.