Diversity of undergrowth types in frankincense stands in Humbang Hasundutan Regency

Abstract Understory plants are one of Indonesia’s biodiversity. The presence of undergrowth has an important role in the ecosystem and economy of the surrounding community. Research on the diversity of understory plants in the Frankincense forest has never been carried out. This research aims to determine the diversit y of understory plants in incense stands in Humbang Hasundutan Regency. Sampling was carried out using understory vegetation analysis plots. Analysis of the distribution pattern of incense using the standardized Morisita’s index. Based on the results of vegetation analysis at the understory level, 27 types of understory plants were found in community forests, with the most dominant type found being the fern (Diplazium esculentum) with an IVI value of 25.90%. In the protected forest, 16 types of understory plants were found with the most dominant type being Etlingera elatior with an IVI value of 31.48%. Species diversity in community forests (2.76) is in the medium category and in protected forests (2.48) is in the medium category. Species richness (R) in Community Forests is 4.34 in the medium category and in protected forests is low (2.36).