A broad comparison of plants across five continents reveals the same link: species that grow slowly tend to reach an older age.
In trees, this relationship was already well documented through annual growth rings. Rapid growth is often accompanied by a shorter lifespan. The question remained whether this rule also applied to perennial herbaceous plants, vines, and small woody plants.
Giant sequoias in Sequoia National Park, California. These trees are among the longest-lived woody plants.
Wikimedia image.
Some plants that live for several years produce annual rings in their tissues, like those in tree trunks. By counting and studying these marks, researchers can reconstruct their growth.
The team compiled data on more than 3,100 species of herbaceous plants and small woody plants. The samples came from five continents and very different environments. They ranged from cold Arctic regions to hot semi-desert areas, making it possible to test the relationship under highly varied conditions.
The result remains remarkably consistent at this scale: slow growth is associated with greater longevity. This relationship is found across several forms of plant life and many environments. It therefore does not appear to be a feature limited to large trees or a few ecosystems.
Temperature also plays a role in this relationship. Across the study as a whole, higher temperatures are associated with faster growth. Yet plants that grow quickly also tend to live for less time. Researchers thus observe an indirect link between heat and longevity: warmer environments are associated, on average, with shorter lifespans.
This does not mean that a rise in temperature will systematically accelerate the growth of every plant. Depending on the environment, heat, drought, or other stresses may instead slow it down. The study primarily highlights a general trend observed across many species and regions.
Plant lifespan also affects carbon storage. A plant that retains its tissues for a long time can keep carbon in its biomass for a different period than a fast-growing species. Changes in the composition of plant communities may therefore alter how long carbon remains stored on the continents.
Researchers can now track how rising temperatures simultaneously affect growth and longevity in different species, then incorporate these relationships into models describing the future evolution of vegetation.