The effects of ontogenetic maturation in Pinus patula - Part 1: nursery performance

Abstract

The age at which parent or donor hedges reach ontogenetic maturity has frequently been cited as a debilitating factor in the production of conifer cuttings. This point varies between species and prevailing environmental conditions. Among other things, a lack of knowledge of the effects ofhedge maturation in Pinus patula has resulted in reluctance among South African foresters to plant cuttings of this species. Consequently, several trials were established between 2000 and 2003 to investigate the effects of ontogenetic maturation on the performance of P. patula cuttings in the nursery and field. This paper forms the first component of a three-part series and reports on those effects observed in the nursery. The effects ofhedge maturation on field performance and cycling of P. patula hedges as a means of rejuvenation, are reported separately. An analysis of the nursery data indicates that rooting efficiency, root system quality, and stem size and form, all decline with increasing hedge age. A decline in root system quality was particularly apparent and was observed prior to a decline in rooting efficiency.