Anne Eskild Nilsen

Senior Engineer

(+47) 976 87 764
anne.eskild.nilsen@nibio.no

Place
Ås H8

Visiting address
Høgskoleveien 8, 1433 Ås

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Abstract

Motivation Trait variation within species can reveal plastic and/or genetic responses to environmental gradients, and may indicate where local adaptation has occurred. Here, we present a dataset of rangewide variation in leaf traits from seven of the most ecologically and economically important tree species in Europe. Sample collection and trait assessment are embedded in the GenTree project (EU-Horizon 2020), which aims at characterizing the genetic and phenotypic variability of forest tree species to optimize the management and sustainable use of forest genetic resources. Our dataset captures substantial intra- and interspecific leaf phenotypic variability, and provides valuable information for studying the relationship between ecosystem functioning and trait variability of individuals, and the response and resilience of species to environmental changes. Main types of variable contained We chose morphological and chemical characters linked to trade-offs between acquisition and conservation of resources and water use, namely specific leaf area, leaf size, carbon and nitrogen content and their ratio, and the isotopic signature of stable isotope 13C and 15N in leaves. Spatial location and grain We surveyed between 18 and 22 populations per species, 141 in total, across Europe. Time period Leaf sampling took place between 2016 and 2017. Major taxa and level of measurement We sampled at least 25 individuals in each population, 3,569 trees in total, and measured traits in 35,755 leaves from seven European tree species, i.e. the conifers Picea abies, Pinus pinaster and Pinus sylvestris, and the broadleaves Betula pendula, Fagus sylvatica, Populus nigra and Quercus petraea. Software format The data files are in ASCII text, tab delimited, not compressed.

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Abstract

Background Progress in the field of evolutionary forest ecology has been hampered by the huge challenge of phenotyping trees across their ranges in their natural environments, and the limitation in high-resolution environmental information. Findings The GenTree Platform contains phenotypic and environmental data from 4,959 trees from 12 ecologically and economically important European forest tree species: Abies alba Mill. (silver fir), Betula pendula Roth. (silver birch), Fagus sylvatica L. (European beech), Picea abies (L.) H. Karst (Norway spruce), Pinus cembra L. (Swiss stone pine), Pinus halepensis Mill. (Aleppo pine), Pinus nigra Arnold (European black pine), Pinus pinaster Aiton (maritime pine), Pinus sylvestris L. (Scots pine), Populus nigra L. (European black poplar), Taxus baccata L. (English yew), and Quercus petraea (Matt.) Liebl. (sessile oak). Phenotypic (height, diameter at breast height, crown size, bark thickness, biomass, straightness, forking, branch angle, fructification), regeneration, environmental in situ measurements (soil depth, vegetation cover, competition indices), and environmental modeling data extracted by using bilinear interpolation accounting for surrounding conditions of each tree (precipitation, temperature, insolation, drought indices) were obtained from trees in 194 sites covering the species’ geographic ranges and reflecting local environmental gradients. Conclusion The GenTree Platform is a new resource for investigating ecological and evolutionary processes in forest trees. The coherent phenotyping and environmental characterization across 12 species in their European ranges allow for a wide range of analyses from forest ecologists, conservationists, and macro-ecologists. Also, the data here presented can be linked to the GenTree Dendroecological collection, the GenTree Leaf Trait collection, and the GenTree Genomic collection presented elsewhere, which together build the largest evolutionary forest ecology data collection available.

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Abstract

Seed from orchards, established from breeding programs, often dominate the planting stock in economically important tree species, such as Norway spruce. The genetic diversity in seed orchards’ crops depends on effective population size which in turn is affected by many factors such as: number of parents in the orchard, seed orchards’ design, fecundity, and pollen contamination. Even though seed orchards’ seed is extensively used over large regions, very few studies have addressed how well their crops reflect the genetic diversity present in the regions where they are planted. Here we have investigated the genetic diversity (by means of 11 microsatellites) of two Norway spruce seed orchard populations with different number of parents (60 and 25) and compared this with seed crops collected in the semi natural forest and natural unmanaged populations. We found that the ratio between the effective population size (N e ) and actual number of parents (N) varied between 0.60 and 0.76 in the orchards’ seedlots. A reduction in genetic diversity (mainly allelic richness) was detected in a few seedlots, mainly where the number of parents was low. Our results also show that pollen contamination play an important role in maintaining the genetic diversity in orchards’ seedlots, particularly when the number of parents is low. The population genetic structure among seed orhcards and natural populations is shallow suggesting that re- generation with seed from current seed orchards will have limited effect on the overall genetic diversity.