The autumn frost hardiness of Scots pine (Pinus sylvestris L.) populations from Scandinavia (57°28’-68°54’ N, 13°00’-27°00’ E) and the Komi Republic in Russia (61°30’-64°20’ N, 49°10’-54°50’ E), and open pollinated families from a population in Komi (61°43’ N, 51°07’ E) were examined in artificial freezing tests with one-year-old seedlings. The aims were to estimate genetic variation in hardiness between families of Russian origin and to compare populations of Russian (continental) and Scandinavian (maritime) origins. The longitudinal distance between the Scandinavian and Russian seed sources was associated with a significant difference in climatic conditions. At latitude 63°N the degree of continentality (the difference between July and January monthly mean temperatures) was 23.7°C for longitude 15°E in Sweden and 35.2°C for longitude 54°E in Komi. The narrow-sense heritability of frost hardiness calculated for the Russian families was 0.22. This indicates relatively high genetic control of the trait, of similar magnitude as earlier shown for populations of Scandinavian origin. Both Scandinavian and Russian populations showed a strong clinal variation in frost hardiness, northern populations being the hardiest. In addition, Russian populations were more frost hardy than Scandinavian ones from corresponding latitudes and attained the same level of hardiness as Scandinavian populations from 4.1° latitude further north. The results indicate that the longitude or continentality of the origins of Scots pine populations is associated with adaptive pressures that have significant effects on hardiness and are distinct from photoperiodic effects. When enriching breeding or production populations by including populations from remote origins it is essential to recognize not only latitudinal origin, but also longitudinal origin or temperature regime, in order to match material to the planned utilization areas.

Understanding local adaptation has become a key research area given the ongoing climate challenge and the concomitant requirement to conserve genetic resources. Perennial plants, such as forest trees, are good models to study local adaptation given their wide geographic distribution, largely outcrossing mating systems and demographic histories. We evaluated signatures of local adaptation in European aspen (Populus tremula) across Europe by means of whole genome re-sequencing of a collection of 411 individual trees. We dissected admixture patterns between aspen lineages and observed a strong genomic mosaicism in Scandinavian trees, evidencing different colonization trajectories into the peninsula from Russia, Central and Western Europe. As a consequence of the secondary contacts between populations after the last glacial maximum (LGM), we detected an adaptive introgression event in a genome region of ∼500kb in chromosome 10, harboring a large-effect locus that has previously been shown to contribute to adaptation to the short growing seasons characteristic of northern Scandinavia. Demographic simulations and ancestry inference suggest an Eastern origin - probably Russian - of the adaptive Nordic allele which nowadays is present in a homozygous state at the north of Scandinavia. The strength of introgression and positive selection signatures in this region is a unique feature in the genome. Furthermore, we detected signals of balancing selection, shared across regional populations, that highlight the importance of standing variation as a primary source of alleles that facilitate local adaptation. Our results therefore emphasize the importance of migration-selection balance underlying the genetic architecture of key adaptive quantitative traits.

Phenology can have a profound effect on growth and climatic adaptability of long-lived, northern tree species such as Scots pine ( L.), where the onset of growth in the spring is triggered mainly by accumulated heat, while cessation of growth is related to the joint effect of photoperiod and temperature. In this study, the objectives were: (1) to compare shoot phenology of genetic material from Scandinavia (maritime climate origin) and northern Russia (continental climate origin) sources, under field conditions in both Scandinavia and Russia (maritime and continental growth conditions); and (2) to estimate the heritabilities of phenological parameters. The material used was part of a larger provenance test series involving Scots pine populations and open-pollinated plus-tree families from Russia, Sweden and Finland. Terminal shoot elongation was measured on multiple occasions during the seventh growing season from seed at a trial near Bäcksjön (Sweden) and Syktyvkar (northern Russia). We calculated the regression of relative shoot elongation over accumulated heat sum above +5 °C using an exponential expression. Seedlings of Swedish and Russian provenance had similar heat-sum requirements for growth onset and cessation in both trials. More northern provenances started onset and cessation at a lower temperature sum, but heat accumulation requirements for onset were not fixed. Scots pine may suffer from spring frost due to earlier growth onset in a warming climate. Variation and heritability of phenological traits show potential to adapt Scots pine to new climate conditions by breeding.Pinus sylvestris

No abstract

Vitality and height growth of two Larix species and provenances in a field trial located in north-west RussiaFedorkov A. (2014). Vitality and height growth of two Larix species and provenances in a field trial located in north-west Russia. Silva Fennica vol. 48 no. 1 article id 1053. 7 p. Highlights• Differences in tree vitality among provenances were insignificant (p > 0.05) at an early age.• The provenance effect was significant (p < 0.05) for total height.• These findings were in agreement with those of Lukkarinen et al. (2010) using the same material at the same age for field trial located in Punkaharju (Finland). AbstractVitality and height of Larix species and provenances originating from Russia were estimated in a 5-yr field trial performed in the Komi Republic (north-west Russia) using a fully randomized single-tree plot design with 7-8 blocks. Tree provenance had no significant (p > 0.05) effect on tree vitality, though for Larix sukazcewii originating from the European part of Russia, trees from the northern regions were more vital than those from southern regions. Provenance was a significant (p < 0.05) factor for height, where the average height of 136 cm varied considerably (168 cm for trees from Nizhnij Novgorod and 111 cm for trees from Ufa). There were no significant correlations when vitality and height were compared to geographic and climatic variables for the locations.

A field experiment with artificial soil contamination by the heavy metals copper and nickel was established in Kola Peninsula, northern Russia. To study the effect of soil contamination by heavy metals without SO 2 air pollution on the Scots pine trees growth the experiment was located outside the range of forest damage due to emissions from a copper-nickel smelter. Retardation in tree diameter growth over 15 years after contamination with 20 kg of metallurgical dust per 100 m 2 plot was 54%, 10 kg 27%, 5 kg 16% and 2.5 kg 7%, respectively, compared with growth in control plots. Thus, decreasing Scots pine growth due to heavy metal pollution was demonstrated.

Gremmeniella abietina damage was studied at stand and tree level on the Kola Peninsula and in northern Finland. At stand level, damage was recorded in four areas in Finland, while only individual damaged trees were found in Russia. According to the results of branch analysis, there was no sign of endemic epidemics in any of the areas. There was a significant negative correlation between the average G. abietina damage and modelled SO, deposition and temperature sum along the gradient. The results suggest that G. abictina is distributed all over northern Finland and the Kola Peninsula in natural' stands of Scots pine, and that the direct effect of SO2 deposition from the Monchegorsk nickel smelter on the damage may be minimal.

No abstract