Jie Li, Beijing Forestry University in China, discusses their article: Cross-scale effects of multi-strata plant diversity on ecosystem multifunctionality in temperate forests
What makes a forest thrive? While we often admire towering trees in a forest, what happens under their shade—the herbs, ferns, and small plants carpeting the forest floor—can be just as important. In our recent study, we investigated how the diversity of both trees and understory herbs work together to support “ecosystem multifunctionality”—the ability of forests to provide a wide range of ecosystem services, from storing carbon to supporting forest regeneration.
The overlooked layers of life
Forests are multilayered systems. We usually focus on trees, the dominant and most visible layer. But forests also include rich communities of understory herbs. Ignoring the undergrowth may mean we’re missing half the story.
A forest-wide investigation
We carried out our study across eight mountainous regions in northeastern China, among the most extensive temperate forest ecosystems in the world. We measured how diverse the tree and herb communities were, and how well those communities contributed to “ecosystem multifunctionality”.
What we found
At the stand scale, forests with more types of trees performed better. They stored more carbon, supported more growth, and had richer soils. But the diversity of herbs didn’t matter as much at this small scale. However, when we looked at the landscape scale, herb diversity became just as important as tree diversity. In fact, forests with different herb species in different locations showed more variety in how they functioned across the landscape. In other words, having different kinds of herbs in different places helped the forest as a whole perform better.
Our study emphasizes that protecting tree diversity alone is not enough. Understory herbs—the quiet companions of forests—also matter, especially when we consider broader scales. Conserving biodiversity across all forest layers is essential to maintain the full suite of services that forests provide.
A moment in the field
One of the most unforgettable moments during our fieldwork happened in the mixed conifer-broadleaf forests of the Changbai Mountains. As we were surveying the understory vegetation, we looked down and noticed something unusual in the center of a large fern. We found a hidden nest, surrounded by a rich mix of herbs and ferns, reminding us of how full of life the forest floor can be. It’s easy to overlook this lower layer of the forest, but it plays a vital role—not just for plants, but for birds, insects, and many other creatures.
Looking ahead
Forests are like buildings with many floors. If we only focus on the top floor, we miss what’s happening below. To keep forests strong and resilient, we need to care for all layers of life, from the tallest trees to the smallest herbs.
