Bamboo, palm, and banana trees look and act like trees, but are actually closer to grasses in how they grow because—unlike trees—their stems do not grow wider over time. However, due to their towering structure, scientists struggled with how to both classify them and to fully understand their biology—and benefits.
A new analysis by New York University scientists offers a clearer picture of these organisms, labeling them "grassy trees," which combine the canopy structure of trees with the resilience of grasses—and can more easily adapt to and recover from extreme weather conditions than can trees.
"Bamboo, palms, and bananas, which don't fit neatly as 'trees' or 'grasses,' are actually a powerful group of plants we call 'grassy trees' that combine the best of both worlds," explains Aiyu Zheng, a researcher at New York University's Department of Environmental Studies and the lead author of the analysis, which appears in the journal Trends in Ecology and Evolution. "Their hybrid nature—combining the tall structures of trees with the rapid growth of grasses—makes grassy trees powerful allies in responding to climate change.
"They bounce back quickly after fires, storms, or harvesting—and they help restore landscapes, store carbon, support biodiversity, and sustain communities. Their benefits stretch from food and jobs to renewable materials and green energy."
"Our study provides the first global overview of how much carbon grassy trees capture and store, showing that they are abundant, practical, and deeply embedded in tropical cultures— and thus deserve to be at the same table as other better-known nature-based solutions," adds Mingzhen Lu , an assistant professor in NYU's Department of Environmental Studies, the paper's senior author.
This new, more precise identification is crucial, the paper's authors emphasize, because it establishes a standardized framework that will more accurately map grassy trees' distribution and quantify what they deliver—from carbon storage and biodiversity gains to economic benefits. For instance, biodegradable plastic can be made from bamboo to help diminish global plastic waste. This knowledge could better inform governments and communities in their planning and investing in sustainable-development initiatives.
"Because these species are widely cultivated and locally familiar across much of the tropics—such as village groves, natural forests, and commercial plots—this research turns 'grassy trees' into a practical playbook: pick the right species, support locals' successful planting and management efforts, and track outcomes—the carbon they capture, the income they generate, and the depth of their resilience," adds Zheng.
The researchers compiled datasets on 12 ecosystem types dominated by trees, grasses, or grassy trees (represented by palms, bamboo, and bananas). They compared above-ground and below-ground carbon stocks and productivity—i.e., how quickly plants capture carbon dioxide to grow. The 12 types span from tropical, temperate, and boreal forests (tree-dominated) and savannas, grasslands, and croplands (grass-dominated) to bamboo forests as well as palm and banana plantations (grassy-tree systems).
They found that bamboo-, palm-, and banana-dominated ecosystems—typically not incorporated into any existing categories—stood out from other tree- and grass-dominated ecosystems. They tended to have higher productivity than did tree- or grass-dominated systems, while their carbon storage capacity was intermediate—lower than that of trees but higher than that of grasses.
The authors also presented three successful examples of using different grassy tree species based on local community needs and development priorities to demonstrate grassy trees as versatile climate solutions:
The moriche palm in South America, which sustains wetland biodiversity and conservation while providing communities with nutritious fruits and oil
Lowland bamboo in Ethiopia, which restores degraded soils and water and fuels a fast-growing green industry that creates jobs
Bananas in Southeast Asia, which shade diverse home gardens, boosting food security and rural incomes
The researchers also examined where grassy trees could both thrive and deliver the most benefit. Here, they synthesized data from the UN Food and Agriculture Organization from more than 30 countries reporting significant bamboo or palm growing areas to identify high-opportunity regions where grassy-tree resources could support accessible sustainability solutions.
"By acknowledging grassy trees as a unique form of growth, we've now set the stage for future research that will better illuminate their ecological and social value," concludes Zheng.
