Root Growth and Rooting of Basswood

Seedling root growth of basswood (Tilia americana L.) was observed in soil pits between nursery rows, in pots (by inverting the soil ball), and in Lucite cylinders in the greenhouse. Root growth occurred primarily during late spring, summer, and fall in the nursery. It occurred throughout the year in the greenhouse. Stem girdling or continued removal of buds led to decrease and cessation of root growth. Gibberellic acid applied to buds had no evident effect on root or shoot growth. Rooting was achieved for leaf-bud cuttings under mist. Such cuttings from twigs pretreated with naphthaleneacetic acid had a much higher percentage rooting than those untreated, but bud break did not take place and establishment of rooted cuttings was not achieved in any leaf-bud cuttings. Hardwood cuttings treated with growth-regulating compounds and stored at low temperatures showed callus growth and bud break but no evident rooting or survival when outplanted.