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Why is much of the plant biomass in tundra ecosystems found below ground?

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tundra biome — Polar ecosystem Southern limit of Arctic tundra and approximate line of demarcation between Low and High Arctic.

In tundra ecosystems, a significant portion of plant biomass is located below ground as an adaptation to the harsh environmental conditions of these regions.1

Because the growing season is extremely brief—often limited to only two to four months—many tundra plants are perennials that rely on underground structures, such as runners or underground stems, to increase their numbers and survive from one year to the next. These underground parts provide a stable reservoir for energy and nutrients, allowing plants to initiate growth rapidly as soon as temperatures rise and snow begins to melt.1

Furthermore, the surface environment is characterized by extreme cold, drying winds, and a short, intense period of potential growth. By investing in below-ground biomass, plants can better protect themselves from these surface stressors. Additionally, many species depend on these underground organs for reproduction, as they may set few seeds in the challenging climate. This strategy ensures the survival and persistence of plant communities in an ecosystem where above-ground conditions are frequently inhospitable.12