Abstract
The contribution of Douglas-fir (Df) to European forests is likely to increase as the species is a potential adaptation option to climate change. In this study, we investigated growth and survival of Df seed sources to fill a knowledge gap regarding recommendations for the future use of Df provenances in Poland. Our experimental test site represents the most continental climate among all Df trials installed in the IUFRO 1966–67 test series in Europe. At this unique single site, we evaluated the performance of 46 Df provenances from North America, and nine local landraces of unknown origin. Repeated measurements of tree diameter, height, and volume were analysed, to age 48, representing integrated responses to geographic and climatic conditions. Significant variation in survival and productivity-related traits were found, with the interior Df provenances performing best, in contrast to previous European reports. The higher survivability and volume of the interior provenances resulted from their superior frost resistance. The low precipitation seasonality at the location of seed origin provided an additional advantage to the trees at the test site. Geographic and climatic factors of seed origin explained most of the variation in productivity (77 and 64%, respectively). The tested landraces exhibited diverse performance, implying that naturalized local seed sources in Poland need improvement and perhaps enrichment with new genetic material from North America, while considering geography and climate. Assisted migration programs should consider the limitations imposed by both frost and drought events in guiding future Df selections for continental climates. Further field testing, early greenhouse screening and DNA testing are also recommended.
Highlights
With ongoing climate change occurring at a speed far exceeding the natural adaptive abilities of forest trees (Davis and Shaw 2001; Nathan et al 2011), forestry faces new challenges in the context of afforestation and possible changes in species composition of forest stands (Allen et al 2010)
Observations of provenance trials from the 1966–67 International Union of Forest Research Organizations (IUFRO) Df collection established in Poland, enriched by progeny from the populations previously introduced to Poland, has allowed for early recognition of both frost resistance and survival rate in selected provenances (Burzyński 1990)
We found that the greatest variation in productivity-related traits was explained using five bioclimatic variables: annual mean temperature (MAT), temperature annual range, mean annual precipitation sum (MAP), isothermality, which quantifies the day-to-night temperature oscillations relative to the summer-to-winter oscillations, and precipitation seasonality (PS coef. of variance)
Summary
With ongoing climate change occurring at a speed far exceeding the natural adaptive abilities of forest trees (Davis and Shaw 2001; Nathan et al 2011), forestry faces new challenges in the context of afforestation and possible changes in species composition of forest stands (Allen et al 2010) These challenges put the long-term provenance experiments carried out around the world in a new light, providing new information to support matching provenances with projected future climates for assisted migration programs (Wang et al 2006, 2010; Rousi et al 2012). Those early plantings of Df, resulted in the existence of well-adapted mature stands today (Chylarecki 2004), the parental origin of these stands remains unclear These long established stands have naturalized to the Polish landscape, forming local landraces (Zobel and Talbert 1984), making them a potential ideal source of seed for future use. The lack of sufficiently accurate prediction power of these models, in terms of the growth potential of specific Df provenances at more continental sites, and the fact that the relative performance of provenances may vary through time, prompted the undertaking of more detailed research focused exclusively on Polish conditions
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
