Developing methods for pre-harvest inventories which use a harvester as the sampling tool

Summary Mechanised harvesters, with their measurement technologies and on-board computer power, provide an opportunity to augment, or in some cases replace, traditional pre-harvest inventory systems and to reduce inventory costs. A brief review of the literature on the tree measurement errors associated with pre-harvest inventory systems indicates that they may be no less than errors found in recent studies of harvester measurements in New Zealand, the United States (Oregon) and Canada. Developmental trials of harvester-based inventory systems in Australia indicate that using a harvester to destructively sub-sample could provide reasonable estimates of volume and log grade provided that it has the same in-built assumptions and optimisation systems as the harvester undertaking the actual harvest. Greater than 92% of predicted value recovery could be obtained. Further work is required on such topics as sampling systems, area determination, costs and operating procedures.