02/19/2026
A large global study analysing over 31,000 tree species has found that forests around the world are changing rapidly, becoming less stable and less diverse.
Although many forests appear to be growing faster, they are increasingly dominated by fast-growing tree species. These trees grow quickly after disturbance but tend to be short-lived, weaker, and more vulnerable to drought, disease, storms, and climate stress.
At the same time, slow-growing, long-lived trees - which form the structural foundation of forest ecosystems - are declining. These species typically store more carbon, stabilize soils and water systems, and support complex networks of animals, fungi, and other plants.
As these slower species disappear, forests become more uniform, a process known as forest homogenization. This reduces biodiversity and makes ecosystems less resilient to environmental change.
Human activities are the main driver of this shift, including:
* deforestation�
* intensive forestry�
* habitat disturbance�
* global movement of non-native tree species�
Fast-growing and introduced trees often spread easily in disturbed environments, but they rarely replace the ecological roles of native species.
The greatest risks are expected in tropical forests, where many unique slow-growing species exist only in small regions and may face extinction.
Overall, the research suggests that future forests may look greener and grow faster, but function more like fragile plantations than resilient natural ecosystems, reducing their ability to store carbon and protect biodiversity.