Assessing the Effects of Root Preparation Methods and Irrigation Strategies for Urban Tree Growth and Establishment

Drought and constrained municipal budgets are increasing demand for establishment practices that conserve water and labor. This study quantified trade-offs between inputs (water, labor, cost) and tree outcomes across irrigation methods and root-ball correction practices during establishment of American sycamore (Platanus occidentalis L.). In December 2022, forty-five 45-gal trees were planted in Gainesville, Florida, in a completely randomized design combining three root treatments (control, shaved, sliced) with three irrigation methods (hand watering, hydrogel bag, conventional slow-release bag). Over 23 months, trunk caliper, height, midday stem water potential, and anchorage (bending stress at 1° inclination) were analyzed using linear mixed-effects models; survival, labor, water, and cost inputs were compared descriptively. Labor differed by two orders of magnitude, but total cost ranked nearly opposite. All trees survived; irrigation method affected no measured response: trees receiving no scheduled irrigation after an initial hydrogel charge were indistinguishable from those hand-watered 48 times (differences within 10–12%). Shaving increased the bending stress required to tilt the trunk 81% over controls, indicating firmer anchorage, without altering growth or water status; slicing had no effect. Under the dormant-season, average-rainfall conditions tested, shaving improved anchorage at negligible cost, and irrigation method had no measurable effect on tree performance.