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NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.

2026

2025

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Sammendrag

Seedling emergence constitutes a critical recruitment step, and early growth relates to plant competitive ability. Understanding their drivers has implications for forestry and forest ecosystem conservation, restoration, and adaptation to climate change. We seeded 6984 acorns in an experiment with 97 cases at 45 sites in 15 European countries, encompassing 12 oak species. We tested whether the quality of the acorn batch, site-level weather and soil characteristics, year of seeding, and species’ mean specific leaf area (SLA) affected the emergence and early growth of seedlings after the first summer. Germination potential and acorn dry weight, measured under controlled conditions, were positively associated with emergence and early growth. Seedling emergence was negatively associated with the mean monthly temperature and cumulative winter precipitation, and it was higher in the seedling cohort that was spared from the 2021 drought. Additionally, seedling emergence was positively related to soil nutrient concentration and negatively to increasing soil pH, but not to water-holding capacity, and growth was unrelated to soils. Species-level SLA was not related to either response. The four main study species –Quercus cerris, Q. ilex, Q. petraea, and Q. robur– responded similarly to weather but not to soil conditions. We conclude that, at a continental scale, and assuming that species establish within their current distributions, (a) oak seedling emergence and early growth are associated with acorn quality rather than species identity or SLA, (b) they are highest at sites with low winter precipitation and temperature, (c) emergence is reduced in dry years, and d) soil properties play a secondary role at this early recruitment stage.

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Sammendrag

Seedling functional attributes (i.e., morphological and physiological traits driving water, carbon, and nutrient economy, as well as stress resistance and resilience) influence the early performance of forest plantings. Nursery environment and cultivation practices interact with species ecology to shape these attributes and potential outplanting success. Although extensive literature exists on these topics, studies that have quantitatively synthesized findings to generalize plant quality and nursery cultivation theory are almost nonexistent. This chapter quantitatively reviews the effects of (1) seedling size and shoot-to-root mass ratio (S/R) and (2) several nursery cultivation practices on outplanting survival and growth. Examined practices include stock type (container vs. bareroot (BR)), drought and blackout hardening, container properties in oaks and pines, and growing media alternatives to peat. For this, we developed different databases compiling information at a global scale from scientific and technical literature in different languages. Seedling size significantly enhances outplanting survival when comparing seedlings of the same age, while S/R does not. Stocktype and species-specific leaf area (SLA), a trait related to resource acquisition capacity and stress resistance in plants, modulate the effect of morphology on survival, particularly on arid sites. In dry climates, large seedlings have a survival advantage over small seedlings in low SLA species (i.e., slow growth and high stress resistance plants) cultivated in containers, if water stress is mitigated through intensive soil preparation, and using 1-year-old seedlings. When stock types differ in survival, container plants usually outperform BR stock, especially if soil preparation is performed, and under dry and high weed competition conditions. Drought hardening improves survival, especially in shrubs, but can negatively affect survival in drought-sensitive species on low aridity sites. Blackout reduces field growth, particularly in drought-tolerant species. The effect of container characteristics on survival differs between oaks and pines: for oaks, reducing plant spacing in small to moderate containers (<400 mL) is preferable to maximize survival, while for pines, increasing container depth is more effective. Peat alternatives, including manure, organic waste, and rice hulls, improved survival, whereas sludge performed poorly. Rice was most effective on humid sites, while manure and organic waste showed consistent benefits across climates. Our findings highlight the potential for peat alternatives, with effectiveness depending on local ecological and economic conditions. Based on these results, we provide recommendations to match seedlings’ size and S/R to species' SLA, stocktype, soil preparation intensity, and aridity of the planting site, along with cultivation guidelines for producing such a variety of seedlings.