Rongxu Shan and Zilong Ma from Sun Yat-sen University, and Han Y.H. Chen from Lakehead University discuss their article: Functional traits and individual tree growth relationship weakens with stand development but strengthens with increasing temperature.
Forests are far more than just collections of trees: they are vibrant, dynamic ecosystems where each tree’s growth strategy plays a critical role in shaping the forest’s overall health, productivity, and capacity to store carbon. But were you aware that the link between a tree’s physical traits and its growth rate isn’t fixed? It evolves as forests age and climate changes.
We analyzed data from nearly 9,828 forest plots and 228,981 trees across the eastern United States to investigate how functional traits, such as leaf chemistry, wood density, and maximum height, influence tree growth under varying environmental conditions and across different stages of forest development.
What are “acquisitive” and “conservative” trees?
Trees can be broadly classified into two strategies. Acquisitive species are fast-growing trees with high nutrient concentrations in their leaves, lower wood density, and high efficiency in capturing light. They grow rapidly but are often less resilient to stress. In contrast, conservative species grow more slowly, produce denser wood, have more durable tissues, and excel in stress tolerance. They may take longer to grow, but they often live longer. While it’s commonly assumed that acquisitive trees always outperform conservative ones in growth, our research reveals a more nuanced story.
Key findings: Age and temperature matter
In younger forests, acquisitive trees significantly outpace conservative ones. However, as forests mature, this growth advantage diminishes. Older forests feature intensified competition for light and nutrients, which levels the playing field and allows stress-tolerant conservative species to catch up.
In regions with higher mean annual temperatures, acquisitive trees grow even faster relative to conservative species. Longer growing seasons and greater photosynthetic energy amplify their growth potential. Interestingly, increased water availability didn’t always benefit acquisitive trees. In some cases, it heightened competition, ultimately favoring conservative species.
Broadleaf trees (angiosperms) grew better with high-nutrient levels, whereas conifers (gymnosperms) often grew more slowly under the same conditions. This divergence underscores the importance of evolutionary history in predicting tree growth.
Why does this matter for forest management?
Many forest management and carbon sequestration initiatives prioritize planting fast-growing, acquisitive species to maximize short-term carbon capture. However, our findings indicate that this approach may lose effectiveness as forests age. For conservation forests designed to provide long-term ecosystem services, blending acquisitive species with conservative, longer-lived trees could enhance both sustainable carbon storage and resilience to climate change. In commercial forestry, managers might consider (1) implementing shorter rotation cycles to maintain the growth advantage of acquisitive trees and (2) selecting warmer planting sites to leverage the accelerated growth of acquisitive species.
Looking ahead
Our study highlights that tree growth strategies are not static—they shift in response to forest development and climatic conditions. Understanding these dynamics enables more intelligent and adaptive forest management practices that balance immediate objectives with long-term sustainability.
