Forests worldwide are undergoing a significant transformation, becoming increasingly uniform and dominated by fast-growing “sprinter” trees, according to a comprehensive global study published in Nature Plants. This shift is driven by human activities such as climate change, deforestation, and logging, which are prevalent in tropical and subtropical regions where biodiversity is highest. Slow-growing, long-lived tree species are disappearing, making way for fast-growing species like acacia and eucalyptus. However, these species are more susceptible to disease, drought, and climatic shocks, compromising the stability and carbon storage capacity of forests. The study, which analyzed over 31,000 tree species, warns that this transformation has significant implications for ecosystem health, biodiversity, and climate change mitigation efforts. When specialized, native species disappear, they leave gaps in ecosystems that alien species rarely fill, even if those species are fast-growing and highly dispersive. The study highlights the growing role of naturalized (non-native) tree species, which share similar “sprinter” traits and can thrive in disrupted environments.
Researchers found that fast-growing tree species are becoming increasingly dominant while specialized, slower trees face a growing extinction risk. Jens-Christian Svenning from Aarhus University notes that this trend is deeply concerning for unique species in tropical regions. These “sprinter” trees establish themselves quickly, yet they often lack the resilience found in the older, more stable species. Furthermore, alien species rarely fill the ecological gaps left behind when native, specialized trees disappear from their local environments.
A new study has shed light on the alarming decline of slow-growing tree species, which are the backbone of forest ecosystems and play a crucial role in maintaining environmental stability and carbon storage. These ancient trees, characterized by thick leaves, dense wood, and remarkable longevity, are being pushed to the brink of extinction by fast-growing “sprinter” trees that are taking over forests worldwide. The species under threat are primarily found in moist tropical and subtropical forests, which are hotspots of global biodiversity. Their disappearance will not only lead to a loss of biodiversity but also compromise the ability of forests to regulate water cycles, with far-reaching consequences for the planet. These slow-growing trees are the actual backbone of forest ecosystems,” said Jens-Christian Svenning, a senior author of the study. They contribute to environmental stability and vital long-term carbon storage, and their loss will have devastating impacts on our planet. The researchers warn that the continued decline of these ancient trees will have severe consequences, including reduced carbon sequestration, disrupted water cycles, and loss of ecosystem resilience. Urgent action is needed to protect and promote slow-growing tree species, and to adopt sustainable forest management practices that prioritize the preservation of these ecological treasures.
Current levels of climate change and exploitation favor trees with lighter leaves and lower wood density, such as eucalyptus. Although species like acacia and pine grow rapidly, they remain highly vulnerable to drought, pests, and sudden climatic shocks. Therefore, the shift toward these “sprinter” trees makes forests less stable and less effective at cooling our hot weather. This lack of resilience means that future forests may struggle to survive the increasing frequency of extreme global storms.
Trees are essential to life on Earth because they absorb CO2 and support diverse webs of animals and fungi. However, the loss of biodiversity makes these ecosystems grow less resilient to the changing conditions of our modern world. Scientists used the massive data set to map how forests will likely change over the next few coming decades. Ultimately, we must prioritize the protection of slow-growing species to ensure that forests can continue to provide vital resources.
Recent research highlights the increasing dominance of naturalized tree species, which are plants that originated elsewhere but grow wild. Nearly 41 percent of these naturalized species share specific traits, such as rapid growth and small leaves. These biological characteristics help them survive and thrive in environments that have been heavily disturbed by human activity. However, these opportunistic trees rarely replace the essential ecological roles previously held by the original native tree species. Moreover, naturalized species intensify the competition for vital resources like light, water, and nutrients in many changing landscapes. This increased competition makes it significantly harder for native trees to survive in their own traditional habitats.
The study indicates that tropical and subtropical regions will likely experience the most severe impacts from forest homogenization. These areas serve as home to many slow-growing tree species that naturally exist within very small geographic ranges. Because these trees are confined to limited areas, they risk disappearing entirely if fast-growing species take over. Furthermore, experts forecast that naturalized and fast-growing species will continue their rapid spread throughout the entire world. In the colder parts of the Northern Hemisphere, the dominant dynamic is expected to be a species invasion. This shift toward uniformity makes forests less resilient to future environmental shocks like pests or extreme weather.
According to researchers, human actions are the primary force behind these dramatic changes in global forest composition. Human-driven climate change, deforestation for infrastructure, and intensive logging all play a significant role in this ecological transition. Additionally, global trade in various tree species has accelerated the introduction of non-native plants into new regions. Often, the timber industry actively promotes fast-growing trees because they produce wood or biomass at an incredibly quick rate. Unfortunately, these “sprinter” species are frequently more fragile and prone to diseases compared to their slow-growing counterparts. This focus on quick profits often comes at the expense of long-term forest stability and carbon storage.
Future modeling scenarios suggest that naturalized species will become even more dominant in the coming decades ahead. Therefore, protecting slow-growing tree species is becoming an increasingly urgent task for conservationists and forest managers. We must implement new strategies that actively support rare species and prioritize the restoration of entire ecosystems. When establishing new forests, managers should place far more emphasis on planting slow-growing and rare native tree species. This proactive approach would make our forests more diverse and resilient to the challenges of a changing climate. Additionally, these species interact positively with large animals, which are also vital for maintaining healthy ecosystem functions.
