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[ID: 517] Predicting tree population growth rates from plant functional traits, nutrient acquisition strategies, and climate
PI: Maria Martell
For over a century, ecologists have sought to understand how plant strategies enable populations to persist and thrive under specific environmental conditions, including water and nutrient acquisition strategies - especially those mediated through associations with mycorrhizal fungi. Plant strategies can be understood through the connection between (i) population growth, (ii) functional traits, and (iii) the environment. (Laughlin et al., 2020; Siefert & Laughlin, 2023), integrating individual- and population-level processes, and providing a clearer understanding of how traits influence growth at both scales. However, the relationship between traits and population fitness is not universal, it depends on the abiotic environmental context, including both atmospheric and soil conditions. By simultaneously considering plant functional traits, population growth across species, and abiotic environmental variation, we can integrate functional ecology and population ecology. Although nutrient acquisition strategies vary within and among mycorrhizal types, general patterns exist: arbuscular mycorrhizal fungi (AMF) typically scavenge soluble inorganic soil phosphorus and nitrogen, whereas ectomycorrhizal fungi (EcMF) rely on specialized extracellular enzymes to extract nutrients, particularly organic nitrogen and phosphorus from complex sources. However, how these contrasting mycorrhizal association types shape individual and population growth across different abiotic environmental contexts remains an open and understudied question. Recent work by Augusto et al. (2025) has challenged the traditional fast–slow plant economic spectrum. In field studies, they found that acquisitive tree species often grow slowly under natural conditions. Their results showed negative correlations between tree growth and traits such as leaf nitrogen content (Nmass), specific leaf area (SLA), specific root length (SRL), and mass-based maximum photosynthetic rate (Amax). They interpreted this mismatch as the outcome of environmental constraints: conservative species grew better in stressful conditions due to greater tolerance, while acquisitive species only grew well in environments with high soil fertility and ample moisture. 2 Here, we propose a complementary framework, beyond the classic fast-slow plant economic spectrum, to explain these findings, grounded in eco-evolutionary optimality theory (Wright et al., 2003; Wang et al., 2017; Franklin et al., 2020; Harrison et al., 2021). This approach introduces the idea of carbon cost relative to carbon gain, integrating nutrient acquisition strategies - particularly those shaped by mycorrhizal associations - with environmental constraints. By linking trait expression and population growth to resource economics and mycorrhizal type, we can better predict when and why certain functional strategies succeed across abiotic environmental gradients. Building on this foundation, our recent work demonstrated that nutrient acquisition strategies shape the trade-off between carbon costs of nutrient acquisition relative to water acquisition and soil resource availability (Cheaib et al., 2025b,a). Specifically, we found that the correlations between the carbon costs of nutrient acquisition relative to water acquisition, and soil nutrient concentrations (nitrogen and phosphorus), varies systematically with the type of mycorrhizal association and local abiotic environmental conditions. A key insight from our study is the role of soil carbon-to-nitrogen (C:N) ratios in determining the relative advantage of different strategies. Under high soil C:N ratios reflecting low soil N availability, tree species associated with ectomycorrhizal (EcMF) and ericoid mycorrhizal fungi were able to reduce carbon costs relative to species associated with arbuscular mycorrhizal fungi (AMF) by accessing organic nitrogen sources. In contrast, under low soil C:N ratios reflecting high soil N availability, species associated with AMF were able to reduce carbon costs relative to species EcMF-associated species by efficiently absorbing soluble inorganic nitrogen. These findings highlight the dynamic nature of plant-soil-atmosphere interactions and suggest that advantages or disadvantages of a given nutrient acquisition strategy are not fixed in space, but context-dependent. In this proposal, we aim to apply these insights - together with new analyses and additional datasets - to revisit and reinterpret the results of Augusto et al. (2025). By framing their observed trait–growth relationships within an eco-evolutionary optimality perspective, and explicitly incorporating nutrient acquisition strategies, we may uncover deeper mechanisms driving population-level growth rates across abiotic environmental gradients. This approach promises to bridge physiological ecology, population dynamics, and mycorrhizal symbiosis within a unified predictive framework.
[ID: 516] SKS Hyggesfritt och skador
PI: Martin Goude
Uppdrag från Skogsstyrelsen att ta fram en rapport/kunskapssammanställning om hyggesfritt och skador. Adriana Puentes och Martin Goude är projektledare och arbetar tillsammans med analytiker på Skogsskadecentrum.
[ID: 515] Arvidsjaur FIRE chronosequence
PI: Michael Gundale
Society is actively debating the role of rotational forestry in delivering a multitude of ecosystem services, including biomass production, biodiversity, and climate benefits. These debates are based on incomplete information about how these ecosystem services are delivered across the full rotational time scale of managed forests relative to young and old natural forests over comparable timescales. Key knowledge gaps our research will fill include: a) How do key ecosystem services change over time in response to rotation forestry compared to recovery from wildfire? b) How does rotational forestry impact these ecosystem services relative to unmanaged primary Swedish forests (i.e. old growth forests)? c) At what time point during rotational forestry are break-even points achieved for key ecosystem services, such that potential trade-offs between productivity, climate benefits, and biodiversity are minimized? To achieve this we will measure ecosystem services across two contrasting forest age gradients, one wildfire recovery gradient (spanning 3 and 370 years since stand replacing wildfire) and one rotation forestry gradient (spanning the full age spectrum of a typical 100-year rotation period). The project will deliver the exact data needed to help resolve societal debates regarding forest ecosystem services, as well as empower key forest stakeholders to more optimally manage forests for the climate transition.
[ID: 514] Spatio-temporal trends in microbial biodiversity in natural and modified (ditches, Dreams) small forest waterways
PI: Cedric Åkermark
By combining rare year-round microbial data from 2012 with resampling in 2026, this project aims to uncover how climate and forestry-driven changes have shaped the hidden biodiversity of Sweden’s smallest—and most overlooked—forest waterways. Water samples will collected during the regular Krycklan water sampling occasions of 2026. The samples will be filtered and stored in Umeå and sent to Uppsala for DNA analysis.
[ID: 512] 512 Genetic variation in drought responce
PI: Martin Goude
This project aims to evaluate how different provenances and breeding material of Norway spruce are affected by drought. Plots containing different breeding material will be covered with roofs below the canopy to simulate drought. Various measurements of tree and site responses will be used to answer the research questions.
[ID: 511] Bullmark Water
PI: Hjalmar Laudon
This project is related to project 414 Rewetting effects on the GHG balance of a high-productive peatland forest but with a focus on the water dynamics in the area. The initiial project had the following purpose: The purpose of this project is to evaluate the climate impact of restoring drained peatland forests in boreal Sweden. Specifically, the project will deliver a first-time estimate of the GHG balance for a high-productive peatland forest undergoing ecological restoration to increase biodiversity. A comparison with data from other nearby drained, restored and natural peatland sites (Hälsingfors, Trollberget and Degerö) will unravel differences in their climate impact. Thus, insights from this project will provide forest and nature stakeholders with invaluable science-based decision-support for developing sustainable and climate-responsible management strategies for forestry on drained boreal peatlands.
watergreenhouse gas emissionsrestoration of drained peatlands
[ID: 508] Microclimate Soil Microbes
PI: Paul Kardol
Forests are vital for human well-being, especially through their role in carbon cycling—a process threatened by climate change. When forests shift from absorbing carbon to releasing it, they worsen global warming and harm biodiversity. However, we still lack a clear understanding of how climate change will affect carbon cycling, largely because research often overlooks the link between large-scale climate (macroclimate) and the local conditions (microclimate) that directly influence plants and soil microbes. This project aims to fill this gap by studying how the disconnect between macroclimate and microclimate impacts carbon cycling and soil microbial activity in different forests, covering a latitude range of 5 degrees (Asa till Svartberget). We will explore how forest structure affects this decoupling and use controlled experiments to simulate climate change scenarios, focusing on the effects of aboveground and belowground microclimates on soil microbes. We will investigate the effect of microclimate on soil-microbial communities by comparing their composition (DNA sequencing) and activity (CO2 respiration) between different macroclimates (Asa, Grimsö, Svartberget) and respective microclimates, as well as observing changes during a controlled warming experiment in the lab.
[ID: 507] Trial 93 at the former Kronoparken Åheden, also known as trial 2179 at Rödåheden
PI: Fredrik Sjödin
One of the oldest forest trials in Sweden established 1907. Approx. 180 yrs old pine stand (2025). Valueable growth records with long continuity. New data, charts and summary of trial contributed by Björn Elfving 2025-10-29 added to Safedeposit by Fredrik Sjödin 30-10-2025. Added to series BB11 äldre gallringsförsök. https://silvaboreal.com/?p=trial&id=2179 Similar trials. Quote BE. The areas I have had contact with and that fit into this group are, in addition to site 93: site 1 near Lycksele, site 479 near Juktan, site 5 andersön in Storsjön, site 773 near Robertsfors (if it can still be saved from the construction of the Botniabanan; northern Sweden's oldest pine plantation), site 595 north of Norrköping, site 196 NW Vättern (cluster trials, preserve the 3-m cluster). End quote.
pinethinningold forestlong continuitycarbonselective cutting
[ID: 506] Björkgallring
PI: Linnea Larsson
Gallringsförsök i björk i norra Sverige. Etablering och mätning av gallringsförsök i björk i Sverige. Mer info finns internt under esf-SafeDeposit.
[ID: 505] Test av plantskydd mot viltbetning 2025
PI: Stefan Eriksson
Test av en ny produkt, avsedd att skydda barrträdsplantor mot viltbetning. Anlagt på uppdrag av Norsk Wax AS 2025.