Scientists solve why tall and short trees thrive together in forests
Researchers from Kyoto University have discovered that trees of different sizes coexist in old-growth forests by balancing light interception efficiency and light use efficiency. This finding challenges the traditional view of forest succession as a simple competition for height and sunlight.
Why it matters
Understanding these forest dynamics is crucial for improving the accuracy of climate models that rely on forest growth data to predict carbon sequestration.
Updated: July 10, 2026 1 min read Follow us on Share this Article Forests are commonly thought of as arenas dominated by height, where the biggest trees hoard sunlight, hoping to turn their smaller neighbors into shadows. So violent is the competition in these early years that this stem-exclusion phase plays out brutally: shorter trees die, leaving a canopy dominated by giants.
Yet in old-growth forests, something remarkable happens. Trees of vastly different sizes coexist, creating layered canopies that defy the idea that only the tallest can win.
A team from Kyoto University set out to understand this paradox. “The competition for light among trees is frequently referred to as an evolutionary arms race, but trees of vastly different sizes successfully coexist in mature forests,” says first author Yusuke Onoda.
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