Tree Improvement

Tree improvement encompasses the systematic enhancement of forest tree performance through the application of genetics, silviculture and biotechnological tools. Traditional programmes rely on the identification of superior “plus” trees in stands or provenance trials, controlled crossing in seed orchards and repeated progeny testing to capture additive genetic variation. Advances in molecular markers, genomic selection and tissue-culture techniques have accelerated breeding cycles, increased precision in trait introgression and facilitated the clonal multiplication of elite genotypes. Contemporary objectives include boosting growth rate and wood quality, improving resistance to pests, diseases and abiotic stresses, and conserving adaptive potential under climate change. By integrating field provenance studies with marker-assisted selection and vegetative propagation, modern tree improvement seeks to supply high-quality, genetically diverse planting stock that fulfils productivity targets, supports ecosystem restoration and maintains long-term forest resilience.

Research from Nature Portfolio

Assisted migration simulations for major European tree species indicate that matching seed provenance to anticipated future climates can preserve or even enhance the above-ground carbon sink. Models show that reliance on local genotypes alone would lead to a substantial decline in carbon sequestration by mid-century, whereas using seed sources pre-adapted to warmer, drier conditions can sustain current carbon uptake rates. This work highlights the role of proactive genotype deployment in maintaining forest function under rapid climate shifts.

Analyses of radial growth increments across the Canadian boreal forest reveal that rising atmospheric dryness, as measured by summer vapour pressure deficit, is already suppressing tree growth at hundreds of sites. Both current and prior-year drought severity contribute to reductions in ring width, with younger cohorts and species such as white spruce exhibiting the greatest sensitivity. These findings underscore the urgency of breeding for drought resilience and incorporating moisture-use efficiency into improvement objectives.

Research from all publishers

Field trials of assisted migration in Canada and Mexico, involving seed sources moved beyond their historical ranges, demonstrate that matching provenance climate origin to projected plantation site conditions can mitigate maladaptation. Success depends on seedlot composition, nurse-plant use and monitoring of invasive potential. These trials offer practical guidelines for provenance selection, site matching and risk management when implementing facilitated gene flow.

A major-effect locus controlling timing of bud set was identified in European aspen through whole-genome resequencing and common-garden phenotyping. Variation at the PtFT2 gene accounted for over 60% of variation in phenology along a latitudinal gradient, facilitating adaptation to shorter growing seasons at northern sites. This discovery illustrates that single loci of large effect can play a pivotal role in rapid local adaptation and offers a direct target for marker-assisted provenance selection.

A genome-wide association study in Norway spruce uncovered 52 single-nucleotide polymorphisms in 39 candidate genes affecting wood density, microfibril angle and growth traits. Application of functional multilocus mapping enabled the identification of genes involved in cell-wall biosynthesis and phenology. These markers provide breeding targets for concurrent improvement of mechanical wood properties and yield in conifer breeding populations.

Tree Improvement publication trend

The graph below shows the total number of articles in tree improvement across all publications each year (not limited to Nature Index journals).

Technical terms

Assisted migration: The deliberate transfer of seed or planting stock to sites projected to become climatically suitable in the future.

Provenance: The geographical origin of seed or breeding material, reflecting local adaptation to climate and soil conditions.

Seed orchard: A plantation of selected genotypes managed to produce improved seed under controlled pollination.

Genetic gain: The improvement in average performance of progeny compared with the parental population, measured in quantitative traits per breeding cycle.

Heritability (h²): The proportion of phenotypic variation in a trait that is attributable to genetic factors in a specific population and environment.

Quantitative trait locus (QTL): A chromosome region containing one or more genes that contribute to variation in a quantitative trait.

Genomic selection: A breeding method using genome-wide marker data to predict the breeding value of individuals for complex traits.

Genotype–environment interaction (G×E): Variation in the performance of genotypes across different environments, affecting stability and adaptability.

References

1. Assisted tree migration can preserve the European forest carbon sink under climate change. Nature Climate Change (2024).
2. Increasing atmospheric dryness reduces boreal forest tree growth. Nature Communications (2023).
3. Assisted Migration Field Tests in Canada and Mexico: Lessons, Limitations, and Challenges. Forests (2020).
4. A major locus controls local adaptation and adaptive life history variation in a perennial plant. Genome Biology (2018).
5. Genome‐wide association study identified novel candidate loci affecting wood formation in Norway spruce. The Plant Journal (2019).
6. Forest tree genomics: growing resources and applications. Nature Reviews Genetics (2011).