How forests can thrive in a hotter world: a new TRANSFORMIT paper
Forests cover nearly one third of the world’s land and play a key role in supporting biodiversity, regulating climate, and human wellbeing. But climate change, with rising temperatures, more frequent “hotter droughts,” and stronger disturbances, is pushing many forests beyond what they can naturally handle. A new review from the TRANSFORMIT project, published in New Phytologist, offers a science- and mechanism-based roadmap for climate-smart forest management under these rapidly changing conditions.
The paper explains how heat and drought affect trees ecophysiology. It explains how water shortages and high air dryness (high vapour pressure) can damage a tree’s water system, reduce growth even before photosynthesis declines, and change how trees store and use carbon. These stresses make trees more vulnerable to pests and diseases. If the stress lasts too long, it can lead to water transport failure or carbon deficiency, ultimately causing forests to die.
From carbon sink to carbon source?
At the forest level, these effects are serious, as stressed trees store less carbon, change how nutrients move through the ecosystem, and in very extreme years, forests can even release more carbon than they absorb. Crucially, the authors move beyond diagnosing the problem. The study shows that climate impacts affect not just individual trees but the whole forest and the benefits it provides.
Climate-smart Forest Management strategies
The authors go beyond describing the problem and explore how forest management can help. They focus on five main strategies:
- tree species selection (including assisted migration)
- Mixing different tree species
- Regulation of stand density,
- Creating structural diversity (with trees of different ages, heights, and layers)
- Managing nutrients
Rather than offering one-size-fits-all solutions, the study highlights trade-offs—for example, between drought resistance and growth efficiency—and stresses the need for adaptive, flexible strategies.
One particularly innovative contribution is the integration of “dryland mechanisms” into climate-friendly forestry. Characteristics such as hydraulic redistribution, water uptake via the leaves, and cooling of the canopy through convective heat flow, which are common in arid ecosystems, could be proactively promoted in temperate forests to improve resilience to future climate conditions.
The authors conclude that uneven-aged, structurally diverse mixed forests, combined with careful species choice and targeted thinning are most likely to offer the greatest resilience and therefore withstand extreme heat and drought. They also stress that long-term experiments and close collaboration between scientists and forest managers are needed to test and improve these approaches.
Safeguarding biodiversity, carbon stargae & forest multifunctionality
By connecting forest management with how trees respond to climate stress, this TRANSFORMIT paper provides a robust scientific foundation for keeping forests healthy and multifunctional—supporting biodiversity, storing carbon, producing timber, and protecting communities—even in an uncertain climatic future.