Statistical evaluation of bud development theories: applicatio

els based on alternative bud development theories applied to Betula pendula Roth data. Statistical testing based on the bootstrap method showed that the mean square errors (MSE) of the predicted bud-burst dates of two models, in which the start of ontogenetic development depended on dormancy development only, did not differ significantly. However, the MSE of the model in which the start of ontogenesis depended on a signal from light climate, indicated by using a fixed calendar date, was significantly smaller than that of the models depending on dormancy development. Model parameters were highly multi-collinear; i.e., sensitive to changes in the data. The crossvalidation method was used to determine the prediction error of the models. The predictive ability of the models was not much less for an independent data set than for the original data.