Tree transplanting practices influence plant survival, establishment, and subsequent landscape value. The inability to adequately quantify effects of inappropriate tree planting and transplanting practices threatens long-term viability and productivity (sustainability) of trees within terrestrial ecosystems. Tree planting depth, i.e. location of the root collar relative to soil grade, is of particular concern for tree growth, development, and performance in the landscape. A series of model studies was conducted to investigate effects of planting depth, container production methods, and transplanting practices on landscape establishment of container-grown trees. Studies included determining the effect of planting depth and soil amendments on live oak (Quercus virginiana Mill.) and baldcypress (Taxodium distichum (L.) L. Rich.), the effect of planting depth during container production and subsequent landscape establishment of lacebark elm (Ulmus parvifolia Jacq.), the effect of planting depth and irrigation practices on landscape establishment of sycamore (Platanus occidentalis L.), and the effect of planting depth and transplant season on landscape establishment of baldcypress. Optimum planting depth varied among species and was dependent on cultural practices and/or environmental conditions. Overall, live oak and baldcypress growth was better when planted with root collars at grade in sand in raised beds compared to planting below grade in control soils. Lacebark elm growth was greater when planted at grade during the initial container production phase and below grade in the second container production phase. Subsequent landscape establishment was variable, but planting at grade to 5 cm above grade produced greater growth. Sycamore trees planted below grade had increased mortality and decreased growth compared to trees planted at grade or above grade, while irrigation had no effect. Baldcypress planted above grade had reduced growth compared to those planted at or below grade, while transplant season had no effect. Species and cultivars within species may differ markedly in their response to environmental/cultural stresses, including planting depth. Each tree species originating from a specific environment may represent an ecotype adapted to that particular environment. Therefore, tree survival and performance may depend on the difference between the environment from which the tree was grown and the experimental system into which it is introduced.
