Mixed forests and wildfires

Mixed hashtag#forests play a fundamental ecological role in our landscapes, widely celebrated for increasing biodiversity and providing a broad range of essential ecosystem services. In forest hashtag#ecology and management, a prevailing assumption is that these mixed forests are inherently better and more resilient to natural disturbances, particularly wildfires, than homogenous pure stands. We often theorise that the higher structural diversity and varied morphological traits found in mixed species provide a natural, protective buffer against fire spread and severity.

However, to robustly check this hypothesis, we must move beyond theoretical assumptions and rely on extensive empirical evidence. This is exactly what we tried to do utilising a massive dataset from the Spanish National Forest Inventory (NFI) to examine post-fire tree mortality across 2,782 plots and over 30,000 trees over a two-decade period.

The main results of this analysis challenged our traditional expectations: mixed stands can actually suffer significantly higher post-fire mortality than pure stands. We found that combining tree species with differing fire-related strategies (such as mixing hashtag#fire-resistant species with fire-resilient ones like Pinus nigra and Pinus halepensis) often exacerbates stand hashtag#vulnerability rather than mitigating it.

This increased hashtag#damage occurs because combining different structural strategies can create a vertical "ladder effect" between the canopy and understory, accumulating higher biomass densities in intermediate layers and ultimately facilitating the spread of fire. While there are notable exceptions where mixing species actually helps, such as the introduction of Quercus robur which was shown to lower mortality in some pine stands, the overarching lesson is clear. We must reconsider the blanket assumption that "mixed is always better" and carefully tailor our management of mixed forests based on specific functional fire traits to truly build fire-resistant landscapes.

Find more: Peris‑Llopis, M., Mola‑Yudego, B., Berninger, F., Garcia‑Gonzalo, J., & González‑Olabarria, J. R. (2024). Impact of species composition on fire‑induced stand damage in Spanish forests. https://doi.org/10.1038/s41598-024-59210-4

Thanks to eco2adapt, Suomen Kulttuurirahasto / Finnish Cultural Foundation, European Forest Institute, European Research Executive Agency (REA), Marie Skłodowska-Curie Actions, Generalitat de Catalunya CERCA

Mapping yields of energy crops in Northern Europe

Willow plantations have long been considered a promising option for #bioenergy in northern Europe. But a basic question remains essential for both investors and #policy makers: how much biomass can actually be produced, and where. It is easy to speak about potential in general terms, but supply planning requires something much more concrete, spatially explicit estimates grounded in real production data.

In this study, we used harvesting records from 1,790 commercial willow plantations in Sweden and combined them with climatic variables to estimate productivity across northern Europe. Rather than relying only on experimental plots, the work was based on commercial plantations, which makes the estimates closer to the biomass that can realistically be harvested and mobilised in practice. The models were then extended to Sweden, Norway, Denmark, Finland, Estonia, Latvia, Lithuania, and the Baltic coastal areas of Germany and Poland.

What we found was a strong spatial variability in yield potential. Precipitation during the growing season, together with key temperature variables, explained an important part of that variation. Under high-performance conditions, average first-rotation yields were above 7 odt ha⁻¹ yr⁻¹ in the Baltic coast of Germany, above 6 in Denmark, above 5 in the Baltic coast of Poland, and between 4 and 5 in much of the remaining study area. This matters because it shows that not all land, and not all regions, offer the same opportunity for energy crops, even within relatively similar climatic zones.

This is, in my view, where the practical value of the study lies. Biomass strategies should not be discussed only in terms of total land availability, but also in terms of realistic productivity, regional differences, and the climatic limits of the crop. Better spatial estimates can improve hashtag#energysystems planning, reduce overly optimistic assumptions, and support more informed decisions on where willow can be a viable part of the renewable energy mix.

At the same time, the study also reminded us of something important: climate explains much, but not everything. Soil conditions, clone choice, and management still matter greatly, especially in the most productive plantations. In that sense, these maps should not be read as fixed truths, but as a solid reference for planning, comparison, and future improvement. For #bioeconomy and #renewableenergy, that is already a very useful step forward.

Mola-Yudego, B., Rahlf, J., Astrup, R., & Dimitriou, I. (2016). Spatial yield estimates of fast-growing willow plantations for energy based on climatic variables in northern Europe. GCB Bioenergy, 8, 1093–1105. https://doi.org/10.1111/gcbb.12332

Where We Plant Matters: Can Poplar Plantations Help Birds Cross Fragmented Farmland?

Across much of Europe, agricultural intensification has broken forest habitats into smaller and more isolated patches, making it harder for forest birds to move through the landscape. This study explored whether poplar plantations, which are already widespread in many farming areas, can help reconnect those fragmented habitats. Using two agricultural sub-catchments in Spain and France, the authors modelled how three forest bird species with different dispersal abilities responded when plantations were added to forest networks inside and outside Natura 2000 areas.

The results showed that poplar plantations can indeed improve connectivity, but not simply by adding more tree cover everywhere. Their value depended strongly on where they were located. Plantations were most useful when they acted as stepping stones between larger forest patches, especially along river corridors. The benefits were also species-specific: birds with medium or long dispersal abilities gained more than short-distance species, which still need habitat patches to be very close together. In other words, the study showed that landscape design matters as much as plantation area.

This is an important message for both land managers and policy makers. Poplar plantations should not be treated as a universal substitute for natural forests, but they can function as complementary elements in fragmented agricultural landscapes. Strategically placed plantations may strengthen ecological connectivity, support biodiversity goals, and improve the wider green infrastructure around protected areas. At the same time, the authors stress that location remains crucial, because plantations may be less helpful in some settings and can even conflict with the needs of open-habitat species if poorly placed. The main lesson is simple but powerful: in biodiversity-friendly land use planning, where we plant may matter as much as what we plant.

Pineda-Zapata, S., Morán-Ordoñez, A., Mola-Yudego, B., & Duflot, R. (2026). Strategic placement of plantations enhances forest connectivity for birds in agricultural landscapes. Landscape Ecology, 41, Article 54. https://doi.org/10.1007/s10980-026-02316-z

Find more information at: https://sites.uef.fi/biopro/

As Europe accelerates its shift toward a low-carbon economy, the pressure to deliver sustainable biomass is rising fast, yet the hardest question is no longer only what to grow, it is where to grow it. Fast-growing plantations and perennial energy grasses can underpin biofuels and biomaterials, while also supporting carbon storage, water protection, and soil functions. However, when these systems expand as large, poorly integrated blocks, they can simplify land use patterns, weaken habitat variety, and reduce ecological resilience. The promise of the bioeconomy, therefore, depends on spatial intelligence: biomass systems need to be placed as part of the landscape, not imposed on top of it.

A recent open-access study addressed this challenge by building one of the most comprehensive empirical pictures yet of biomass production systems across Europe. Using harmonised spatial data for 426,783 fields and stands, covering 2,140,568 hectares across 17 countries, the authors characterised seven representative systems, including eucalypt, radiata pine, black locust, poplar and hybrid aspen, willow, miscanthus, and reed canary grass. They then assessed the land-use context around each site using 1 km buffers and CORINE land cover, translating “how mixed is the surrounding landscape?” into a Land Use Diversity Index based on Shannon diversity. The result was a practical lens for policy and planning: it showed not just where biomass is today, but where it is likely to diversify, or homogenise, the landscapes around it.

The key insight was that context dominates: the same crop can be either a corridor of diversity or an engine of simplification, depending on where it is inserted. Willow stood out as the strongest candidate for diversification, with 57% of willow plantations located in homogeneous, agriculture-dominated areas, where woody strips can introduce structural variety and potentially strengthen multifunctionality. Poplar and black locust also showed meaningful opportunities, with sizeable shares of stands situated where they could add “forested elements” into agricultural matrices. By contrast, miscanthus was often concentrated in low-diversity agricultural settings, suggesting that, without deliberate spatial planning, it may do little to raise local land-use diversity. The study also highlighted a recurring risk signal: biomass areas were highly unevenly distributed, with the largest 20% of stands accounting for the majority of total area, and thousands of very large polygons, a pattern that can translate into landscape dominance when not carefully governed. A sustainable bioeconomy is a design problem, and better maps, better metrics, and better placement rules are as important as better crops.

Read more:
Pineda-Zapata, S., & Mola-Yudego, B. (2025). European biomass production systems: Characterization and potential contribution to land use diversity. GCB Bioenergy, 17, e70057. https://doi.org/10.1111/gcbb.70057
DOI: 10.1111/gcbb.70057

Understanding bioenergy conflicts: Case of a jatropha project in Kenya’s Tana Delta

Bioenergy is often presented as a double opportunity, to reduce dependence on fossil fuels while also promoting rural development. But large-scale bioenergy projects do not unfold in empty landscapes. They enter places with existing land uses, rights, institutions, and histories of inequality. When those realities are ignored, a project framed as green development can rapidly become a source of conflict.

In this paper, we examined the case of a proposed large jatropha plantation in Kenya’s Tana Delta, using Ethical Analysis to understand the positions, interests, and values of the main stakeholders. The case was not only about biodiesel. It was also about who has the right to decide over land, whose livelihoods count, and how “development” itself is understood by different actors.

What we found was that the conflict was structured around four major issues: land tenure, trade-offs between economic and environmental benefits, representation and power relations, and different approaches to development and sustainability. Some actors emphasized jobs, investment and local growth. Others stressed biodiversity, grazing rights, traditional land uses, and the risks of weakly regulated land deals. The disagreement, therefore, was not simply about being for or against bioenergy, but about what kind of rural future was being imposed, and for whom.

Perhaps the most important message was that many of the tensions could have been anticipated. The study identified shortcomings in technical feasibility studies, limited community participation, weak consultation processes, and an insufficient regulatory framework. In that sense, the problem was not only the crop or the investor, but the broader governance setting that allowed such a project to move forward without properly addressing land tenure, local rights, and competing claims over the landscape.

For me, this is where the study still feels very relevant. If hashtag#bioenergy is to contribute to hashtag#climate goals and hashtag#development, it cannot rely only on promises of investment or emission reductions. It also needs credible feasibility, transparent institutions, and meaningful participation from the start. The paper points to Free, Prior and Informed Consent, stronger oversight, and better policy coordination as necessary steps. That is a simple but important lesson for hashtag#policy and hashtag#governance: sustainability is not only about the final product, but also about the process through which land use decisions are made.

Arevalo, J., Ochieng, R., Mola-Yudego, B., & Gritten, D. (2014). Land Use Policy, 41, 138–148. https://doi.org/10.1016/j.landusepol.2014.05.002