Concluding Remarks

Abstract

The most substantial findings and conclusions from the eight preceding chapters are briefly revisited. The need for biological realism in ecophysiological models for the annual cycle of boreal and temperate trees is emphasised, and the need to improve the transparency of the various published models is pointed out. Different models have drastically different degrees of empirical support, and the evaluation of this support is a major theme throughout this book. Even models with sound empirical support from earlier tests may be falsified when they are further tested with more thorough tests. However, models that have been corroborated earlier but falsified later should not be abandoned once and for all, for a lot can be learnt from them. Though the present volume essentially belongs to the discipline of whole-tree ecophysiology, recent studies addressing the upscaling of the models to the ecosystem level are also briefly discussed. In addition, the downscaling of the models to the anatomical, cellular, and molecular levels is also proposed. That would facilitate a synthesis of the whole-tree modelling approach discussed in the present volume and the molecular biology of plants, which is progressing very rapidly today. As to the effects of the projected climate change, the main emphasis is on the hypothesis that climatic warming will increase the incidence of frost damage in boreal and temperate trees due to premature dehardening and growth onset during mild spells in winter and early spring. For several reasons, this hypothesis cannot be ruled out even though experimental tests up to now have not provided support for the catastrophic damage projected earlier. For further evaluation of the hypothesis, more experimental work with different tree species, provenances, and cultivars is needed. The research discussed in the present volume has pointed out not only the ecophysiological traits of the trees that are critical for the hypothesis but also the experimental designs that facilitate the determining of those traits in any tree population.