Comparison of tree growth, wood density and anatomical properties between coppiced trees and parent crop of six Eucalyptus genotypes

Coppicing is a very common practice in South African forestry. It allows a plantation grower to have a second timber rotation without replanting and thus reduces reestablishment costs. While the large variation in wood properties among different Eucalyptus resources is well documented, little information is available on the quality of wood of the coppice shoots and whether it is different from that of the original planted trees. In this paper, tree growth, wood density and anatomical characteristics of coppice and original parent wood were measured using rapid screening tools. Six different Eucalyptus genotypes aged seven years were harvested from a research trial in Zululand, South Africa in 1997. Cut stumps were allowed to coppice and managed to produce one to two coppice sprouts. In 2005, the coppiced stems from the same original trees were sampled at the age of eight years. In total, fifty four trees were selected for both types of wood. The wood of parents and coppiced trees were similar in terms of vessels characteristics and fibre wall thickness. However, the parent trees had significantly smaller fibres with smaller lumen. Consequently, the wood density of the parent trees was higher than that of the coppiced trees. A serious drought which occurred during the growth of the parent trees was associated with marked changes in certain wood properties. This made it difficult to assess the real effect of coppicing on wood quality. The ability to predict the quality of coppiced trees is important for the future strategy of growers. If productivity yield and wood quality of coppiced trees are comparable to those of parent trees, then coppicing would be a preferable option to replanting since it can greatly reduce reestablishment and management costs.