Site variation in Pinus radiata plantations and implications for site specific management

685,000 ha of Pinus radiata(D. Don) plantations in Australia werecategorized using a matrix of mean annualrainfall, rainfall regime and Parent Rock Codefrom a Technical Soil Classification. Datawere obtained from a number of differentorganizations which in total managed nearly allthe Australian P. radiata plantations. The selected characteristics were those whichcould be obtained at an acceptable level ofconfidence from all sources. Such acharacterization of plantation sites provided asystem for utilization of technical informationand extrapolation of research results and alsoa basis for the development of Site SpecificManagement systems. Analysis of theinformation indicated the high degree ofvariability of environments in whichplantations have been established withinAustralia and also the distinctive nature ofindividual regions. Such differences betweenareas make extension of silvicultural andrelated information difficult from one area toanother without appropriate validation. Abroad comparison with 1.26 million hectares ofP. radiata plantations in New Zealandindicated only a small overlap of areas of sitetypes between Australia and New Zealand. Assumptions derived in one location on thesites, characteristics, models and/or genotypeswould require significant testing beforeconfident application could be undertaken toanother area. The value of a Site SpecificManagement system for research planning andapplication of research and operational resultswas demonstrated from analysis of a series ofexperimental trials assessing application offertilizer after thinning and from evaluationof soil carbon in P. radiataplantations.