Tea (Camellia sinensis) is an important cash crop and the most widely consumed beverage in the world. The global tea industry, particularly the booming Pu'er market, has increasingly relied on converting forests to monoculture plantations for higher productivity. This has raised alarms over soil degradation, biodiversity loss, and deteriorating tea quality.

In a study published in Agriculture, Ecosystems and Environment, researchers from Xishuangbanna Tropical Botanical Garden (XTBG) of the Chinese Academy of Sciences identified optimal balance between forest coverage and planting density to boost tea quality and soil health. They demonstrated that integrating medium tea planting density within medium-coverage forests significantly enhanced tea quality, improved soil nutrients, and created a better microclimate compared to conventional monoculture plantations.

The study was conducted in Xishuangbanna, Yunnan, China.

The researchers thoroughly investigated the effects of various habitats and tea planting densities on microclimate, soil nutrients, tea nutrients, growth, and quality.They investigated three habitat types – monoculture (T1), medium-coverage tropical evergreen broad-leaved forest (T2), and high-coverage forest (T3) – combined with two tea planting densities (medium (M) and high (H)). The combination of medium-coverage forest and medium tea planting density (T2 + M) consistently delivered the best outcomes:

The results showed that T2 +M improved the microclimatic conditions of tea plants by increasing the relative humidity and soil moisture while reducing the light intensity, soil and air temperatures. It also significantly boosted soil nutrients across all layers compared to intensive monoculture, increasing total nitrogen, available phosphorus, and available potassium.

Moreover, the T2+M treatment improved tea nutrients and quality. Tea plants in T2+M exhibited higher chlorophyll content, and significantly increased levels of essential nutrients in young shoots and mature leaves compared to others. Crucially, T2+M tea contained dramatically higher levels of key quality compounds: amino acids and catechins– vital for tea flavor and health benefits. Medium tea density consistently outperformed high density across soil nutrients, tea nutrients, growth, and quality metrics.

 "Integrating tea within medium-coverage forests at moderate density is optimal for high-quality tea production. It not only produces higher quality tea with more desirable compounds but also combats soil degradation and supports biodiversity, unlike conventional monocultures. This offers practical solutions for farmers and strong evidence for policymakers promoting agroforestry in the tea sector," said SONG Liang of XTBG.

Available online: 22 July 2025