Response of messmate stringybark regrowth to release in irregular stands of mixed eucalypts

Abstract

Summary The response in basal area and height of messmate stringybark regrowth stems to release from competition over a period of ten years was examined in irregular stands of mixed eucalypts in the Wombat and Creswick Forests. These stands contained a mixture of small trees (dbhob <30 cm) less than 40 years old (regrowth), with larger trees (dbhob to 80 cm) 80 to 100 years old (overwood). Competing stems were identified by the ‘zone count’ method using a 9.2 m2 ha-1 optical wedge. Basal area increment (bai) and height increment of regrowth stems was reduced by competing overwood and regrowth, but regrowth stems retained a capacity to respond when released from this competition. Regardless of crown position within the regrowth stratum, regrowth responded to the reduction in competition, with the magnitude of the response in bai and height increment generally increasing with the degree of release and increasing crown dominance. These results indicate that in the mixed eucalypt forests of central Victoria, where partial cutting is practised, selected regrowth stems, preferably of good form and in the dominant crown position class, can be released from their competitors to reduce the production time for the new crop.