According to new research, Mediterranean forests that are allowed to grow naturally within strictly protected areas can stay up to 2°C cooler during summer heat waves compared to actively managed woodlands. This suggests that passive forest restoration could be a key strategy for mitigating the impacts of rising temperatures and climate extremes throughout southern Europe.

The study, published in Agricultural and Forest Meteorology by a joint collaboration between researchers from the Universities of Tuscia, Bologna, Messina, Milano, and the Carabinieri Forestali corp examined how different management regimes influence forest surface temperature across a coastal landscape in Tuscany, Italy.

Using satellite observations collected between 2013 and 2023, the team compared canopy temperatures in three types of forest: a strictly protected reserve, a nearby natural park, and productive coppice forests managed for wood production.

Forests that cool themselves

Forests are known to moderate local climates by releasing moisture through evapotranspiration. However, until now, little was known about how management intensity affects this cooling effect in the Mediterranean -- a hotspot region expected to warm 40% faster than the global average.

"Strictly protected forests act like natural air conditioners," said lead author Dr. Francesco Solano. "Their taller, complex canopies store more moisture and create stable microclimates that help reduce the impact of heat waves."

Prof. Alessandro Chiarucci, University of Bologna, added, "This cooling effect can provide fundamental support for components of biodiversity which are more sensitive to climate warning, making these sites true climatic refugia."

The researchers used satellite-derived land surface temperature data from NASA's Landsat 8 mission to map canopy-level temperatures across the landscape. They combined these measurements with information on forest structure, canopy height, vegetation moisture, and topography.

Statistical models then identified which factors most strongly influenced temperature differences between sites. Prof. Giuseppe Modica, University of Messina, highlights how "remote sensing technologies combined with on-field measurements represent a crucial asset in defining effective sustainable forest management strategies."

The results showed a clear gradient: average maximum summer canopy temperatures reached about 33.3 °C in the strictly protected area, 34.2 °C in the surrounding natural park, and 35.4 °C in the managed coppice forests. Even after accounting for terrain, vegetation, and moisture levels, the productive forests remained roughly 1 °C warmer than the strictly protected site.

Cooling rooted in structure and moisture

The analysis revealed that forest structure and canopy moisture were the main drivers of cooling. Taller trees, higher canopy density, and greater water content were all associated with lower surface temperatures. In contrast, forests closer to edges -- where trees are more exposed to sunlight and wind -- showed warmer conditions extending up to several hundred meters into the stand.

"This study confirms that forest structure matters," said Prof. Gianluca Piovesan, University of Tuscia. "The more complex the canopy, the greater its ability to buffer against heat waves."

The strictly protected site, Poggio Tre Cancelli Reserve, has been free from logging since 1961. Over more than six decades, its unmanaged holm oak forest has developed into a multi-layered canopy that shades the ground and maintains higher humidity.

In comparison, the surrounding productive forests -- regularly coppiced for firewood -- have shorter trees and more fragmented cover, allowing greater heat penetration.

Implications for a warming Mediterranean

The research highlights how forest protection and restoration can serve as effective nature-based solutions for climate adaptation in one of the world's most vulnerable regions.

The Mediterranean basin is already facing more frequent heat waves, more prolonged droughts, and accelerating biodiversity loss. Maintaining or restoring intact forests could help moderate local temperatures and safeguard species that depend on cooler, stable conditions.

According to the authors, the findings also emphasize the importance of expanding strictly protected areas and allowing natural regeneration to proceed.

"State forests like Poggio Tre Cancelli have shown that allowing some spaces to support natural processes can create the old-growth forests of tomorrow," said Colonel Giovanni Quilghini of the Carabinieri Biodiversity Unit in Follonica.

"Today, additional state-owned woodlands are being designated for rewilding to lay the foundations for the future," added General Raffaele Manicone, head of the Carabinieri Forestali Biodiversity Group.

The study suggests that unmanaged forests not only store more carbon but also create self-regulating microclimates that enhance their own resilience to heat and drought. These effects can reduce the risk of vegetation stress, soil drying, and fire susceptibility -- critical issues for Mediterranean ecosystems.

A natural ally for climate resilience

The authors argue that strict protection, rewilding, and sustainable landscape management should be central to European climate and biodiversity strategies. While the European Union has proposed protecting 10% of its land under strict conservation by 2030, much of this area is currently concentrated in mountain regions. Extending protection to lowland and coastal Mediterranean forests could yield significant local cooling benefits.

"This study proves that strict protection, as promoted by the EU Green Deal, is vital for restoring degraded Mediterranean forests," said Piovesan.

"They provide a living example of how forest rewilding can effectively support the EU Nature Restoration Regulation's goals for recovering degraded forest habitats."

The study highlights that Mediterranean forests, which have been shaped by centuries of human use, still have the potential to recover their ecological functions when management pressures are reduced or removed.

As the climate warms, these resilient forest refuges may become increasingly important not just for wildlife, but also for human well-being in heat-stressed landscapes.

Strictly protected Mediterranean forests stay cooler, study finds