Diversity and Spatial Distribution of the Fagaceae Tree Species in the Doi Suthep-Pui National Park, Chiang Mai Province
Dokrak Marod, Suchada Bootcharee, Wongsatorn Phumphuang, Lamthai Asanok, Torlarp Kamyo, Sathid Thinkampaeng, Jakkaphong Thongsawi, Sutheera Hermhuk, Nathawat Khlangsap, and Wimonmart Nuipakdee
This study aimed to explore species diversity, spatial distribution, and habitat suitability of mountain tree species in the family Fagaceae. The data were collected during the years 2016-2018 from the two sources; 1) primary data such as species diversity and topographic factors, elevation and slope, soil factors, soil texture (% sand and clay), and soil pH, were measured from a total of 60 temporary plots of size 30 m x 30 m. 2) The diversity data, which was collected from selected nature trails. All the specimens of Fagaceae species (leave, flowers, and fruits) were collected identified, while the unidentified species were compared with the identified specimens at the Forest Herbarium, Department of National Parks, Wildlife and Plant Conservation. The Generalized Linear Model (GLM) was used to determine the spatial distribution of some dominant species. The geographic information system (GIS) was then used to detect suitable habitats for some species. Total of 31 Fagaceae species in 3 genera were found, including genus Lithocarpus (12 species), Quercus (10 species), and Castanopsis (9 species). Different sapwood characteristics and acorn morphology can be used for the identification of genus. The temporary plots contained a higher number of species (26 species) compared to the nature trails (21 species). The spatial distribution, based on the GLM analysis, demonstrated that the distribution varied among species and environments. Topographic factors, particularly high elevation (above 1,000 m above sea level, asl.) and sandy clay soil texture, were the most important factors for the evergreen Fagaceae species (Castanopsis acuminatissima, C. diversifolia, and C. armata). In contrast, the low elevation (below 1,000 m asl.) and sandy soils determined the distribution of deciduous Fagaceae species (Quercus kerrii and Lithocarpus polystachyus, C. psudo-hystrix, and Q. kingiana). Suitable habitats for all species were also classified as high and medium potential areas. Our results indicate that the variations in species niches and environmental factors had a high influence on the species abundance.