Comparison of native woody species for use as live stakes in streambank stabilization in the southeastern United States

Abstract

Live stakes are cuttings taken from dormant woody plant species used to establish riparian vegetation. Although many species may be suitable, black willow (Salix nigra) is the species of choice in streambank stabilization projects in the southeastern United States. Studies were conducted on four species native to the southeastern United States that have potential for success as live stakes. Black willow, silky willow (Salix sericea), silky dogwood (Cornus amomum), and Virginia sweetspire (Itea virginica) were evaluated for biomass differences among species, effect of soaking stakes in tap water for 48 hours prior to installation, and differences in survival attributed to season of harvest. The experiment was conducted at the Paterson Horticulture Greenhouse Complex, Auburn University, Alabama. Each species was established from live stakes and had 100% survival when harvested during the dormant season. Total biomass of soaked and nonsoaked live stakes of silky dogwood was greater than soaked and nonsoaked black willow live stakes at nine months. This was driven by below-ground biomass. At nine months, silky dogwood belowground biomass for nonsoaked stakes was greater than belowground biomass for black willow, silky willow, and Virginia sweetspire. Belowground biomass of soaked silky dogwood stakes was similar to belowground biomass of silky willow and greater than belowground biomass of black willow. Soaking live stakes collected in the dormant season for 48 hours resulted in only one significant total biomass difference between soaked and nonsoaked in the species silky dogwood at six months. After nine months of growth, there were no differences between soaked and nonsoaked live stake biomass. Virginia sweetspire, a shrub, consistently had less biomass, diameter, and height than the other species. However, the nine month root:shoot ratio of Virginia sweetspire was greater than both willow species and similar to silky dogwood. There was 0% survival of black willow, silky willow, and silky dogwood after six months when live stakes were harvested during the growing season irrespective of soaking treatment. Live stakes of Virginia sweetspire harvested in the growing season had a survival rate of 80% for soaked stakes and 67% for nonsoaked stakes. The four native species evaluated in this study became established and survived as live stakes. These species are candidates for use in riparian enhancement and restoration projects, which will assist with increasing riparian plant diversity.