Effects of Three Transplant Methods on Survival, Growth and Root Regeneration of Caliper Pin Oaks

Twenty-nine 7–15 cm (3–6 in) caliper Quercus palustris Muenchh., pin oaks, were transplanted 1) bare root, 2) bare root, but treated with auxin impregnated toothpicks (toothpicks were soaked in a 10,000 ppm solution of the potassium salt of indolebutyric acid and one inserted into each of 15 roots per tree), or 3) with a Vermeer 44 Tree Spade. Transplant survival for all treatments was 100%. Leaf expansion, lateral shoot growth, and terminal shoot growth were greatest in mechanically dug trees. However, mechanically dug trees flushed once, while bare-root trees flushed twice. In bare-root trees, leaf expansion for both growth flushes, total lateral shoot growth, and terminal shoot growth were greater in auxin-treated trees than in bare-root trees. More roots of greater diameter and length were regenerated by auxin-treated trees than in untreated bare-root trees.