No abstract

Field establishment of South Africa's most important commercial pine species, Pinus patula, is severely hampered by the pitch canker fungus, Fusarium circinatum. Importantly, hybrids between P. patula and other pine species tolerant to the pitch canker fungus, such as P. tecunumanii and P. oocarpa, have been identified as an alternative planting stock. In this study, variation in tree volume and dynamic modulus of elasticity (MOE dym ) of the P. patula × P. tecunumanii (low-and high-elevation [LE and HE] ecotypes) hybrid was compared with the P. elliottii × P. caribaea hybrid, and the pure species P. tecunumanii (LE) and P. patula. The MOE dym was assessed using the Fakkop TreeSonic microsecond instrument across three sites. The results of the study showed that P. patula × P. tecunumanii LE performed significantly better than P. patula × P. tecunumanii HE for volume and MOE dym , which in turn was significantly better than P. patula. The MOE dym and tree growth decreased with an increase in elevation. There was significant taxon × site interaction for volume and MOE dym . The results of these trials suggested that P. patula × P. tecunumanii LE is a suitable alternative to P. patula in the Sabie region of Mpumalanga in South Africa on frost-free sites, in terms of the traits that were assessed.