Richness and Abundance of Tree Species in the Bonsai Field, Mount Hamiguitan, San Isidro, Davao Oriental

Abstract

The study aimed to assess the richness and abundance of tree species in the Bonsai Field, Mt. Hamiguitan, Davao Oriental. Sampling was conducted within the Bonsai Field, where ten remote-sensed sample plots were established. The presence of bonsai tree species in all plots was recorded, counted, and identified using mechanical sampling with a line plot method. Species identification employed both reference methods and the Indigenous Knowledge System, using local common names for all species. A total of 67 species were documented, of which 38 species (57%) were identified with local names and 29 species (43%) remained unidentified. Seven species showed 100% constancy, and 12 species (18%) had 90% fidelity. Eleven species (16.41%) exhibited high mean density, ranging from 1,000 to over 5,000 stems/ha, with a total mean percent cover of 62.74%. Eleven species were dominant, while 56 were rare. Among dominants, Chinese cedar (Toona sinensis) had the highest mean density (5,280 stems/ha) and percent cover (15.20%), followed by Bitanghol (Calophyllum blancoi) (2,340 stems/ha, 6.88%) and Malasulasi (Leptospermum flavescens Sm.) (2,220 stems/ha, 6.39%). Distribution of bonsai trees showed a clumped pattern; the highest variance values were recorded for Chinese cedar (Toona sinensis) (1,257.73) and Zysigium spp. (Syzygium P. Browne ex Gaertn) (1,138.80), while Unknown species_2 had the lowest (0.50). The Shannon Diversity Index was 3.4060, the Evenness Index 0.8101, and the Dominance Index 21.1416, indicating high species diversity. The data provide baseline information for environmental management, proper utilization of forest resources, and conservation of the Bonsai Field and Mt. Hamiguitan Range.