Survival of Douglas-fir provenances in Austria: site-specific late and early frost events are more important than provenance origin

Abstract

& Key message Autumn and spring frost events caused wide variation in the survival of juvenile Douglas-fir in Austrian forest sites located in the transition zone from Atlantic to continental climate. Survival rate can be optimized by planting provenances originating from an altitudinal belt of 500-1400 m in North America. Neither the variety nor the climate of origin of planted Douglas-fir provenances influence its response to frost events. & Context Understanding the risks of frost during late spring and early autumn is crucial for planting non-native Douglas-fir (Pseudotsuga menziesii [Mirbel] Franco) as an alternative tree species under climate change in Europe. & Aims We investigate the role of early and late frost events on the survival of juvenile Douglas-fir and tested whether survival depends on seed origin. & Methods With data from 19 provenance trials across Austria, we modeled the effects of early and late frost events on juvenile survival rate, accounting for random variations due to site condition and provenance origin. & Results Wide variations (37-93%) in the juvenile survival rate of Douglas-fir were mainly driven by early and late frost events (daily T min < 0°C), summer drought, and continentality. Juvenile survival declined with an increasing number of frost events within the observation period and prevailing warm spells preceding the frost events. The seed origin of the tested provenances had a minor effect and was related to the altitude, but not to the variety or the climate of provenance origin. & Conclusion For planting Douglas-fir in the transition zone from Atlantic to continental climates, typical in Austrian forests, the local site conditions and the probability of the occurrence of early and late frosts should be considered, while provenance selection should rather focus on productivity. Keywords Climate change. Pseudotsuga menziesii. Provenance trial. Extreme events. Early frost. Late frost. Survival This article is part of the topical collection on Forest Adaptation and Restoration under Global Change

Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) in Europe: an overview of management practices

“…), European beech (Fagus sylvatica L.) Rigling 2010, 2012;Manise and Vincke 2014;Nicolescu 2019;Spiecker 2019). Thus, coastal Douglas-fir could be a replacement for Norway spruce, providing high productivity and resilience to climate change (Chakraborty et al 2019;Covre Foltran et al 2020;Frei et al 2022). However, Douglas-fir stands in Europe have suffered reduced growth and dieback during extreme drought conditions, especially at lower elevations (Bastien 2019).…”

How geographic and climatic factors affect the adaptation of Douglas-fir provenances to the temperate continental climate zone in Europe

“…However, the results of our study indicate that frost resistance is, and likely will remain, an important factor affecting early survival and success of Df plantations grown in continental climates, which is critical for plantation success. Future climates are projected to be warmer (Collins et al 2013), but those projections do not preclude the occurrence of extreme weather phenomena, especially the late and early frosts in locations with continental-type climates, and the populations from the interior Df range with superior growth would be desirable for such sites (Chakraborty et al 2019).…”