Symphoricarpos albus

SYMPHORICARPOS ALBUS is a finely-branched, erect, perennial shrub.

Common snowberry occurs on dry to moist, well-drained sites in sun or partial shade, including thickets, woods, and open slopes from lowlands to mid-elevation in mountains.

S. ALBUS and related species provide important winter and summer browse for game animals and for sheep and cattle in areas where grasses have cured or where grass cover is less abundant. Several range and forest management studies have looked at encouraging common snowberry growth and monitoring effects of browsing (Willard and McKell 1973, Szukiel 1981).

Another group of studies has looked at the invasion of this species into grasslands (McLean 1969, Anderson and Bailey 1979, Agee and Dunwiddie 1984). Most research on the species has involved manipulations of individual plants and/or communities, and little literature exists on plant reproduction or ecology in unmanipulated settings.

Willard and McKell (1973) clipped SYMPHORICARPOS VACCINIOIDES for five years to simulate browsing. Treatments involved clipping at the same time each year, under deferred-rotation, alternate rest, and rest rotation grazing systems, each at three intensities (30%, 60%, and 90%) of herbage removal. Sprout numbers were higher in all of the clipping treatments, increasing with increased percent herbage removal. However, sprout mortality increased propor- tionately. Carbohydrate reserves were lowered by annual clipping in July. Future production of twigs, leaves and seeds was reduced by annual 60-90% herbage removals in early or mid-season. However, 30% herbage removal stimulated future production of leaves and twigs.

George and McKell (1978a, 1978b) studied seasonal patterns in car- bohydrate reserves in S. OREOPHILUS. Nonstructural carbohydrate reserves were lowest in May due mainly to a reduction in nonstruc- tural carbohydrate (NC) reserves in small roots and old stems. Carbohydrate levels in large roots and root crowns remained relatively stable seasonally. NCs for leaf production appear to come from stems rather than roots and followed a declining trend in plants fully defoliated at two-week intervals from June 1 to July 15, and on May 15, May 30, and June 15 the second year (George and McKell 1978a). Plants receiving this treatment died at the end of two years.

McLean (1969) categorized species based on their fire resistance by looking at rooting characteristics. The root system of S. ALBUS is described as fibrous with rhizomes which grow between 5 and 13 cm below the mineral soil surface and which show signs of being able to regenerate from those depths. It was predicted to be a fire-resistant plant because roots penetrate below depths that experience the greatest increases in temperature during fire.

Anderson and Bailey (1980) conducted burns in grass and shrublands annually for 24 years. Burns were conducted in April when soil moisture was high. The percent cover of SYMPHORICARPOS OCCIDEN- TALIS was much lower in burned plots than unburned plots; however, there was no difference in frequency. In Kansas, annual early spring burning reduced stem densities of S. ORBICULATUS, while late-spring burning eliminated the species entirely (Smith and Owensby 1972).

Westcott (1982) describes a species of tephritid fly, RHAGOLETIS ZEPHYRIA, the snowberry maggot, that oviposits on snowberry fruits. However, no estimates of infestation rates or effects on seed production were given. Because snowberry spreads mostly by vegetative growth and sprouting (Willard and McKell 1973), it is unlikely that reduction of seed production by flies would result in significant decline in snowberry populations.

Common snowberry spreads mainly by vegetative means through sprouting (Willard and McKell 1973). It reproduces by rhizomes as well as by seed and resprouts after fire or cutting (Tisdale and Hironaka 1981).