Characterizing the Utility of the Root-to-Shoot Ratio in Douglas-Fir Seedling Production

Abstract

Nursery-grown tree seedlings are a vital component of successful restoration and reforestation programs, useful when calls for increased planting for industrial forest management are made, and a tool for climate change mitigation. One of the most extensively planted and studied trees in Western North America is Douglas-fir. Building on that body of work, this review was conducted to identify if the root-to-shoot ratio (root:shoot, R:S), a commonly referred-to metric in reforestation planning, yields meaningful guidance for producing seedlings that are better able to establish across a variety of field conditions. The results indicated that there is wide variability in R:S of nursery-grown seedlings. The relationship between R:S and subsequent root growth and seedling survival varies depending on Douglas-fir variety, seedling stocktypes, and site conditions. The biological and physiological basis for using R:S remains, and likely could be used to enhance seedling quality; however, there is an ongoing need for planning and collaboration between researchers and practitioners to identify how to best deploy this evaluation tool.

Polyvinyl Acetate Binders Undermine the Effectiveness of Biochar-Based Seed Coatings

“…The salinity treatments used in experimental trials (up to 40 mM NaCl) resulted in pronounced reductions in plant biomass (Figures 1, 2 and 4), consistent with prior studies that have found salinity levels as low as 30 mM can induce significant inhibitory effects [62,63]. Cytotoxicity by Na (and to a lesser extent Cl) is generally the most important mechanism for observed growth reduction in plants [64].…”