This paper discusses the genetic composition of high altitude provenances; some of these are special ecotypes developed through natural selection, while others have evolved into independent species. They are mainly distinguished by their morphology and physiology. Morphological adaptations are a response to wind, cold, and snow, resulting in particular branching types (Fig. la) which may become genetically fixed. Physiological changes reflect inherent adaptation to the short growing season in high mountains (Fig. 2); growth is strongly affected by photoperiod, as may be seen even in seedlings (Figs. 3 and lb). Even under climatically favourable conditions, adaptations to both the shorter growing period and the increasing cold lead to lower growth performance of high altitude provenances compared to low altitude ones (Tabs. 1 and 2).
High altitude silviculture must allow for the behaviour of the suitable plants, especially their slower nursery growth, and for appropriate tending in situ. Also, young stock need tending for a longer time at high altitudes than at low ones.