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 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, these studies used data collected on limited sites and/or species, or over successive rotations. To directly compare coppice and planted forest regeneration regimes, 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. Genetically similar trees that were planted or from coppice were compared over the same rotation and site. In the E. nitens and E. macarthurii trials, improved material was also compared with genetically similar, albeit unimproved coppice. Rotation-end data was collected, including stocking, merchantable volume, timber and pulp yield, and profit. Although treatment responses were site and/or species specific, stocking was the main factor that determined treatment ranking, irrespective of the method of re-establishment. Wood density was 1.7 to 3.4% higher in coppice than in the replant treatments, as was the screened pulp yield (2.2 to 3.9%), although this was only significant for the two clones grown within the two sub-tropical sites. Regeneration via coppicing was US$ 474 ha− 1 cheaper relative to re-planting, but the harvesting costs associated with felling coppiced stands was US$ 2.9 wet weight tonnes− 1 higher, with all treatments returning a positive internal rate of return (using a net present value of 6%).