- Background and Aims Neoformation is the process by which organs not preformed in a bud are developed on a growing shoot, generally after preformation extension. The study of neoformation in trees has been hindered due to methodological reasons. The present report is aimed at assessing the relative importance of preformation and neoformation in the development of shoots of woody species. - Methods A deconvolution method was applied to estimate the distribution of the number of neoformed organs for eight data sets corresponding to our Nothofagus species and a Juglans hybrid. - Key Results The number of preformed organs was higher and less variable than the number of neoformed organs. Neoformation contributed more than preformation to explain full-size differences between shoots developed in different positions within the architecture of each tree species. - Conclusions Differences between the distributions of the numbers of preformed and neoformed organs may be explained by alluding to the duration of differentiation and extension for each of these groups of organs. The deconvolution of distributions is a useful tool for the analysis of neoformation and shoot structure in trees.