The combination of persistent droughts and record summer temperatures is accelerating the deterioration of forests in Europe and North America , where the lack of water adds to the risk of fires, the spread of pests and diseases and other effects that threaten the ability of these ecosystems to withstand an increasingly extreme climate.
The United Nations Economic Commission for Europe (UNECE) warns that these pressures are not limited to large forest areas. Urban trees are also suffering the consequences of water scarcity and intense urban heat, jeopardizing a natural infrastructure that helps reduce temperatures, improve air quality, and protect human well-being.
The situation is especially worrying in Europe. According to data cited by the UNECE from the European Drought Observatory, 50% of the territory of the European Union and the United Kingdom is currently experiencing drought conditions , at levels of monitoring, warning, or alert. Severe rainfall deficits are reducing soil moisture and compromising the health of forests.
In parts of Western and Central Europe, the prolonged lack of rainfall has reached historic levels. Certain regions are experiencing their longest and most persistent annual rainfall deficits in more than six decades , a situation that is already causing leaf loss and damage to tree canopies.
Drought, plagues, and fires strike at the same time
The lack of water does not act in isolation. The stress caused by heat and drought coincides with an increased risk of wildfires and other threats, such as aggressive bark beetle outbreaks and plant diseases . The combination of these factors is causing an unprecedented loss of trees in various parts of the region.
This problem adds to an already considerable pressure. UNECE baseline data for 2025 indicate that insects, diseases, and weather events have affected up to 73 million hectares of forests in the region.
Cities are not immune to this situation either. There, trees must simultaneously cope with water scarcity and the so-called urban heat island effect , whereby densely built-up areas register higher temperatures than their surroundings. The deterioration of urban trees can, in turn, reduce the capacity of cities to moderate extreme heat.
This loss would be especially problematic in a context of rising temperatures, since trees and other nature-based solutions are part of the tools used by cities to generate shade, moderate temperatures and contribute to better air quality.
Preparing forests for a more extreme climate
Faced with these increasing risks, countries in the region are trying to shift from responding to crises once they occur to preparing for them in the long term . One of the priorities is improving the available information on the damage caused by phenomena such as droughts, storms, and fires, as well as by pests and other biological agents.
Countries are working on new methodologies to record and share this damage, with the aim of detecting changes in forests more quickly and facilitating public policy responses. These initiatives will be addressed in November during a meeting of the UNECE Committee on Forests and the Forest Industry.
In cities, some of the measures aim to expand and strengthen tree cover and integrate green infrastructure into urban planning. UNECE is also promoting changes in the forestry sector, including greater circularity in timber use and more efficient use of forest products, given the possibility that forest disturbances could affect the availability of raw materials.
Cooperation between countries and forest management that takes the entire landscape into account will be equally important to address threats that transcend borders. The goal, according to the UNECE, is to preserve both the ecological integrity of forests and their economic viability in the face of increasingly demanding climatic conditions.