Forest tree improvement is when control of parentage is combined with other forest management activities, such as site preparation or fertilization, to improve the overall yields and quality of products from forests. Overall results of tree improvement have been so good that we no longer have difficulty in selling tree improvement. Use of genetically superior seedling stock has been considered operational, not just research for over 20 years, by most organisations Zobel et al. (1969). Historical data alone, however, will not sustain the validity of such a claim. For widespread and sustained acceptance of tree improvement programmes as a forest management activity supported by the public and forest industries, demonstrable evidence of improvements in value is necessary. This report analyzes a P. radiata trial throughout New Zealand designed to quantify improvements in stem growth and form traits up to age 12.