TREES REACHING NORTHWARDS How do temperate tree species fare under current conditions in Helsinki beyond their natural range?

Craig Brelsford1 T. Matthew Robson1 David Israel1 Saara M Hartikainen1

Canopy Spectral Ecology & Ecophysiology (CanSEE group) @CanopySEE 1Viikki Science Center (ViPs), Dept. of Biosciences, University of Helsinki, Finland. blogs.helsinki.fi/robson/

A trial of beech and survival, growth & establishment in Helsinki, Finland  264 individuals representing four beech (Fagus sylvatica) provenance populations originating from distinct habitats, climate and latitude, were germinated and grown for 5 months in pots prior to planting at the Helsinki University field plots in Viikki, in Sept 2010. Likewise, four species of Nothofagus were grown and planted concurrently, in the same open field site. Survival, phenology, traits and gas exchange were monitored periodically each growing season.

Anticipating Range Shift of European Tree Species due to Climate  Climate change is expected to threaten some European tree species within their current range. Helsinki - Beech Provenance &  European beech (Fagus sylvatica) is expected to be particularly vulnerable because it is shallow Nothofagus species trial site rooted and somewhat drought sensitive.  Its growing season is determined by chilling during winter, forcing during spring and day length, so these potentially confounding factors will complicate its migration. Blaviksliarna  Beech has high intra-specific variation in adaptive traits, such as bud burst and frost tolerance. Swedish population  Finland is outside the natural range of beech but the climate suggests that it could grow there.

The effect of frost damage on 1000 populations that flush too early Eichelberg, warm central German population 1900 900 1700 800 N. antarctica 1500 700 N.obliqua 1300 600 N.alpina 1100 500 N.alpina Rindelpholz, high elevation, German population 900 400 N.obliqua 700

Elevation (m (m asl) Elevation 300 Precipitation (mm) Precipitation 200 500 100 300 Elevation Precipitation 0 100 Montejo de la Sierra, Madrid 0 10 20 30 40 50 southern-range-limit population N.Antarctica growing at Transect through the north Andes (km West to East) the tree line in the Andes

Results

Species Mean height after 5 years (cm) Nothofagus 79 ± 7 An elevation gradient in the central Andes, antarctica N.obliqua growing covers the range of N.antarctica (tree line) > 59 ± 4 in the Andes N.alpina > N.obliqua (mixed with bamboo) Nothofagus pumilio 58 ± 7

N.pumilio Nothofagus alpina 44 ± 4 N. antarctica Fagus sylvatica 185 ± 7 Rindelpholz Background - South American Nothofagaceae Fagus sylvatica 157 ± 7 Eichelberg DE Nothfagaceae dominate forests of the southern Andes, and comprise nine species – Fagus sylvatica 137 ± 13 six and three evergreen. Montejo ES The four deciduous species growing in the trial occur along a contiguous, but largely Fagus sylvatica 143 ± 9 non-overlapping, cline crossing the Andes from West to East, with niche segregation Blaviksliarna SE based on rainfall, frost and soil depth. Nothfagaceae have been suggested as possible timber species for forestry in northern temperate Europe replacing those native species suffering under climate Performance of beech provenances in Helsinki change and new diseases.  All beeches survived well (<20% mortality; due to rodents) in the provenance trial. An alternative taxonomy for some South American (and some Australasian)  Provenances suffered minor frost damage (to c15% of trees). Bud burst was in early June Nothofagus to become Lophozonia is currently being adopted. and bud burst date differed by only about 5 days among provenances.  The provenances from Rindelphotz and Eichelberg grow highest. They are likely to originate Performance of Nothofagus in Helsinki field trial after 5 years from managed forest. Mortality after 5 years: N. alpina is largely killed (59% ) by late frosts; also N. obliqua  The high elevation provenances from Montejo Spain, and Rindelphotz Germany had the shows substantial damage to the buds and meristems from late frost in Autumn (19% highest constitutive epidermal flavonoids; effective in UV shielding. killed but 44% severely frost damaged). Neither species are able to form a single  The Blaviksliarna provenance from Sweden had most anthocyanins – suggesting adaptation trunk. This result is consistent with patterns from elsewhere in northern Europe. to tolerate temperature fluctuations – but lowest chlorophyll. Of those species expected to be suited to the climate in Helsinki, the N. pumilio,  Overall, all populations established well, but leaf and growth traits suggest that intra-specific surprisingly, suffered extensive damage to its bark leading to death (66%), while variability is large among populations of beech across its range. N. antarctica has been able to survive and grow well in the trial so far (17% mortality  Continued future assessment will test the relative population-level versus acclimatative but not due to frost damage). plasticity of these saplings as they grow into trees.

Funding Acknowledgements We are grateful to Viikki Greenhouse & Field Plots of the University of Helsinki for facilitating the establishment and maintenance of the trial, This research was funded by Decision number #266523 Academy of Finland Research Fellowship in particular Leena Grönholm, Daniel Richterich, and Pekka Lönnqvist. Many thanks to Luis Morales, Pedro J Aphalo, and Fang Wang, for to T. Matthew Robson (2013-2018). help in establishing the field trial, and to Oriane Loiseau,, Antti Takolander, and Pasi Pouta for help in measurements of the saplings.