Dipterocarpus alatus plays a dominant role in the ecology and economics of riparian forests in Thailand. Using MaxEnt modeling, we identified potentially suitable regions for D. alatus along the Chao Phraya River in central Thailand. The modeling procedure used 465 occurrence records and 19 Worldclim environmental factors as well as aspect, slope and elevation data. The results indicated that precipitation is the key influential factor affecting the distribution of D. alatus. Highly suitable regions for this species included Nakhon Sawan, Uthai Thani, Loburi, Phra Nakhon Si Ayudhya, and Ang Thong Provinces along the Chao Phraya River. The statistically significant area under the receiver operating characteristics curve value (0.904) indicated that MaxEnt can be used to accurately predict suitable regions for growing commercially valuable plants such as D. alatus. These model results can facilitate habitat conservation and sustainable resource utilization of rare and important plants.

Urban trees provide numerous ecosystem services in cities such as pollution absorption and reduced urban heat island intensity, energy use, and mental fatigue. Understanding urban tree species diversity can enhance tree planning and management in rapidly urbanizing areas. However, few studies have examined the effects of urbanization on urban tree diversity in Thailand. This study assessed the diversity of large trees in urban landscapes including 11 cities along the 372 km Chao Phraya River Rim in central Thailand. Species diversity, importance value, and distribution were evaluated in each city. Our survey documented 987 large trees belonging to 65 species, 48 genera, and 31 families. The dominant species of Dipterocarpus alatus and Hopea odorata had the highest importance and relative abundance. The highest abundance of large trees was seen in the rural city of Sing Buri, while large urban cities such as Ayutthaya and Bangkok exhibited the highest species diversity. Detrended correspondence analysis indicated that the diversity of unique species was high in large urban cities, while dominant and common species were ubiquitous in rural cities. These findings suggest that large trees are few in number but exhibit high species diversity in large rapidly urbanizing cities. Therefore, preserving good site conditions is critical for the survival of large trees in urban cities. Heritage tree registration may aid preservation efforts and enhance the benefits of these large trees in rapidly urbanizing areas.

The coffee (Coffea arabica L.) agroforestry systems (CASs) of smallholder farmers can enhance species diversity and carbon stock by managing the shade tree component. This study investigated the variation in shade tree composition and carbon stock of CASs along an elevation gradient in Khun Mae Kuang Forest, Ching Mai Province. Data were collected from 80 plots (20 m × 20 m each) that were divided into groups of 20 plots at four elevation ranges: lower (LE), middle-lower (MLE), middle-upper (MUE), and upper (UE). Differences in species composition and carbon stock were examined to determine the effect of elevation on both characteristics. The results show that the shade tree compositions within MLE and MUE were significantly different, dividing the shade tree composition of CASs according to location (lower vs. upper zone). Species richness and stem density were highest in the lower zone (LE and MLE) forest trees and in the upper zone (MUE and UE) horticultural trees. The total carbon stock at each elevation range was high (186.32–264.12 Mg C ha^–1), and increased with elevation. The aboveground biomass carbon of forest trees contributed the most to the CAS carbon stock, suggesting that the CAS system plays a significant role in carbon storage by promoting the conservation of natural trees in highland agricultural. These findings will help to improve CAS management in mountainous areas, as well as biodiversity conservation and efforts to mitigate climate change.