Productivity of radiata pine (Pinus radiata D. Don.) clones in monoclonal and clonal mixture plots at age 12 years

Productivities of monoclonal plots and clonal mixtures of 10 radiata pine (Pinus radiata D. Don.) clones were compared in a trial established in 1993 at Dalethorpe, Canterbury, New Zealand. Ten monoclonal and one mixture of the 10 clones were planted in a complete randomised block design with three replications using 40-tree plots (un-thinned, pruned to 2.5 m, stocking of 1250 stems per hectare). The study was conducted to determine if mode of deployment (monoclonal versus clonal mixture) affected overall productivity and how or if each clone was affected by mode of deployment. The main conclusion was that mode of deployment did not significantly change overall stem volume productivity at age 12 years. All clones contributed equally to overall stem volume productivity in monoclonal plots, whereas in clonal mixture plots 50% of the volume was contributed by four dominant clones. Coefficient of variation (CV) within clones was greater in clonal mixtures compared to monoclonal plots by 3.2% in height and 4.7% in diameter at breast height over bark (DBH). Mean DBH was 13% more uniform (12.6% versus 14.2% CV), mean height was 12% more uniform (7.8% versus 8.7%) in monoclonal plots compared to clonal mixture plots. Overall survival was 90% and was not affected by mode of deployment. Clones exhibited more frequent and greater interchanges of ranks in monoclonal plots. One-third of the 10 clones were relatively over-productive or under-productive in clonal mixture plots. The results of this study suggest that plantation growers should select their preferred mode of clonal deployment based on considerations other than productivity, such as crop uniformity, risks management, and operational efficiencies in tending, harvest, log segregation and subsequent processing and marketing. (c) 2007 Elsevier B.V. All rights reserved.