The Warm-Temperate and Subtropical Forest Research Center of the National Institute of Forest Science (NiFoS), under the Korea Forest Service, has investigated the host plant range and potential habitat of Korthalsella japonica, a representative parasitic plant of warm-temperate and subtropical regions.

Korthalsella japonica is distributed across Japan, China, Taiwan, Malaysia, India, and Australia, and grows on host trees in warm-temperate coastal and island areas of Jeju and the southern coast of Korea. It is a small plant, typically 5–30 cm in length, with segmented stems that branch finely, resembling the needle-like foliage of coniferous trees.

This species is subject to export approval requirements and is classified as Least Concern (LC) on the Red List. It has long been used in traditional medicine; however, increased awareness of its antibacterial and blood pressure–regulating properties has led to unauthorized harvesting, raising concerns over population decline.

Field surveys conducted in Jeju from March to June 2025 showed that K. japonica grows on multiple host species, including Distylium racemosum, Machilus thunbergii, and Actinodaphne lancifolia. The number of recorded host plant species increased from 11 to 26, more than doubling previous records.

Using environmental variables such as elevation, slope, and vegetation, the researchers predicted potential habitats and found that the species is likely to be concentrated in mid-elevation areas and along river systems in Jeju. These findings suggest that as climate change expands the distribution of warm-temperate and subtropical plants, both host diversity and habitat range of K. japonica may increase.

This study provides a basis for the development of management and conservation strategies for K. japonica and identifies candidate host species for artificial mass cultivation. The findings were published in the December 2025 issue of Journal of Ecology and Environment and were selected for the 2026 Outstanding Paper Award by the Ecological Society of Korea.

Eunyoung Lim, a researcher at the Warm-Temperate and Subtropical Forest Research Center of NiFoS, stated, “To manage forests effectively under climate change, it is essential to consider both biodiversity and ecosystem health. We will continue to identify and monitor indicator species such as Korthalsella japonica and advance research on the conservation of warm-temperate and subtropical plant resources.”