Diversity and biomass of understory vegetation which might increase fire risk in Mount Rinjani National Park, Lombok Island, Indonesia

Abstract. Metananda AA, Suhubdy, Mertha IG, Soekardono, Afrianto WF, Ar NH. 2025. Diversity and biomass of understory vegetation which might increase fire risk in Mount Rinjani National Park, Lombok Island, Indonesia. Asian J For 9: 68-75. Human activities in the grassland surrounding Mount Rinjani National Park (MRNP), Lombok Island, Indonesia are prevalent, increasing the susceptibility to fires during the dry season. This study assessed the diversity and biomass of understory species which might enhance the risk of fires in the MRNP. Data collection on species diversity was carried out through exploration (non-plot) and creation of 120 sampling plots in Sikur and Sembalun Sub-district In total, there were 263 species of the understory plants were identified, comprising 71% herbs, 26% shrubs, and 3% lianas. Poaceae and Asteraceae had the largest number of genus and species with the dominance of pioneer species Themeda triandra, suggesting that the grasslands in MRNP have not yet reached climax. This species was among the most preferred natural grasses for grazing cows at the study location, indicating intricate relationship between local communities and grassland ecosystem in the MRNP. Over a span of two years, the dry biomass in the area can reach a thickness of 10 cm, with an estimated weight of 5.7 Mg ha-1. The accumulation of high amount of dry biomass poses high risk of fires. The findings of this study offer a substantial foundation for comprehensive interventions in ecosystem management and forest fire risk mitigation, as well as supporting more planned and sustainable conservation efforts.