Rotation-end comparisons for two Eucalyptus regeneration regimes (coppice versus replant) on four contrasting sites in KwaZulu-Natal, South Africa

With the focus on maximising timber yield on a sustainable basis from a static land base, rather than on a reduction in costs alone, the question of whether to replant or coppice has become increasingly important. Although past research in South Africa has compared coppice growth and wood properties with genetically similar planted material, this data was collected on limited sites and/or species, or over successive rotations. Four trials were established in 1999–2000 in South Africa with either E. grandis x E. camaldulensis , E. grandis x E. urophylla , E. macarthurii or E. nitens , where genetically similar trees and coppice were compared over the same rotation and site. In the E. nitens and E. macarthurii trials, improved material were also compared to the genetically similar, albeit unimproved coppice. As the regeneration regimes were tested under identical site and climatic conditions, a direct comparison could be made between the two. Rotation-end data included stocking, merchantable volume, timber and pulp yield, and profit. Although treatment responses were site and/or species specific, irrespective of method of method of re-establishment, stocking was the main factor that determined treatment ranking. Timber density and screened pulp yield was higher in coppice than in the replant treatments, although this was only significant for the two clones grown within the two sub-tropical sites. Regeneration via coppicing was cheaper relative to re-planting, but the harvesting costs associated with felling coppiced stands was higher, with all treatments returning a positive internal rate of return (using a nett present value of 6%).