Climate Change Threats Lead to Calls for Greater Species Diversity in UK Forests
Thursday, April 24, 2025 — In response to the growing threats of climate change, a recent literature review supported by DEFRA and Teagasc has called for increased species diversity in UK forestry. The paper, published in the Quarterly Journal of Forestry, argues that adopting a mixed species approach to forestry can provide an “insurance policy” against multiple crises, including climate change, biodiversity loss, and domestic timber shortages.
Authored by Andrew Leslie of Forest Research and Ian Short of Teagasc, the paper highlights the potential benefits of mixed species forest stands, which consist of both broadleaves and conifers. These stands are believed to increase resilience to extreme weather, benefit wildlife, reduce damage from pests and diseases, increase productivity, and improve financial returns from broadleaved trees.
According to the authors, this research is particularly important given the current dominant monoculture approach to forestry in the UK, where the majority of woodlands consist of broadleaved trees. Not only does a mixed species approach address climate change and biodiversity decline, but it also aligns with the government’s new Timber in Construction Roadmap, which aims to address housing and climate crises through sustainable building materials and support the domestic timber market.
A comparison of hardwood sawlog production volumes between the UK, France, and Germany reveals a significant disparity. The UK produces six times less hardwood sawlogs per hectare annually compared to France and fifteen times less than Germany, underscoring the need for increased timber productivity.
Co-author Dr. Ian Short, Silviculture Senior Research Officer with Teagasc, stated, “Considering the mounting pressures on our forests from escalating pest and disease outbreaks and the accelerating impacts of climate change, the timing of this review is critical.” He added, “We recognized that while mixed species stands, especially those with broadleaves, constitute a significant portion of the forest area in Great Britain, there’s a noticeable scarcity of formal research specifically investigating their potential for timber production.”
Andrew Leslie, Head of Silviculture and Wood Properties at Forest Research, further emphasized the potential benefits of mixed stands, stating, “The potential for increased timber productivity in these diverse forest stands can contribute to a greater supply of domestically grown wood, potentially supporting the construction sector’s growing demand for timber.” He also highlighted the increased resilience of mixed stands to climate impacts and their potential role in climate change mitigation through carbon sequestration.
In addition to providing economic advantages, mixed stands also offer protection against pests and diseases. With an increasing number of tree pests and diseases reported each year, mixed species stands are seen as an “insurance policy” against potential catastrophic events. By reducing the “apparency” of host trees to pests and pathogens, mixed stands can decrease the transfer of damaging agents between trees of the same species.
Looking ahead, the authors note the need for further research to understand the specific impacts of different species combinations. As extreme weather events continue to threaten monoculture forests, this research is more critical than ever. Dr. Short concluded, “This synthesis is vital to better understand the silviculture of these mixtures and to highlight their potential importance in a rapidly changing environment, particularly as we strive to improve the productivity of our broadleaved woodlands.”
The literature review was supported by DEFRA core funding under the ‘Silvicultural Systems’ project and Teagasc under the ‘RForestS – Diversifying broadleaf stand structures to promote resilience project’. To learn more about the potential benefits of mixed species forests, read the full paper: (2025) Mixed species broadleaved and broadleaved/conifer stands in Great Britain for timber production. Quarterly Journal of Forestry, 119(2): 82-88.
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