Bud set and autumn coloration of Larix sibirica and Larix gmelinii provenances in a field trial in southern Finland

The main aim of this study was to analyse the differences in the bud set, autumn coloration and needle shedding of seedlings in 20 Russian larch provenances and five comparison entries in field conditions in southern Finland over two growing seasons. Furthermore, it was studied if the differences could be explained by the geographic and climatic conditions of the provenance origins. We found that the provenances from cold northern climates developed both their terminal buds first and formed autumn colour as well as shed their needles much earlier than southern provenances. The timing of the bud set occurred earlier in 2008 compared to 2009, which was probably caused by lower than average temperatures in July and August of 2008. Thus, in addition to photoperiod, temperature also seemed to affect the bud set. The southern Dahurian larch provenances were able to utilise the length of the growing season the most effectively. The climatic adaptation, growth and properties of the provenances should be, however,...