Shrestha, Shashi creator Pichdara, Lonn Chairperson Tsusaka, Takuji W. Examination Committee Ekbordin Winijkul Examination Committee Sasaki, Nophea Examination Committee ADB-Japan Scholarship Program (ADB-JSP) Scholarship Donor text series theses th Pathum Thani Asian Institute of Technology 2026 continuing eng

print

106 leaves : ill.+e1 online resource The relationship between tree species diversity and carbon sequestration is a crucial concern in global forest ecology, especially in managed tropical forests where research findings are scarce and frequently contradictory. While international biodiversity{u2013}ecosystem functioning (BEF) studies have largely focused on natural forests, a clear research gap exists regarding how silvicultural systems influence diversity and carbon sequestration. This study addresses this gap by examining tree species diversity, stand structure, and aboveground carbon stock (AGC) in Shorea robusta (Sal) forests managed under the Irregular Shelterwood System (ISS) in Lumbini Province, Nepal.Data were gathered from 47 sample plots, which included 3,553 trees. We used richness, Shannon, Simpson, and evenness indices to measure species diversity and allometric equations to measure AGC. Results indicated moderate species richness (mean = 4.23 species per plot) but low diversity (Shannon index = 0.53) and evenness (0.39), largely due to strong dominance of Shorea robusta (84.1% of individuals). Mean AGC was 60.64 t C ha⁻¹ (range: 21.09{u2013} 137.89). Basal area showed a strong positive association with AGC (r = 0.84, R² = 0.71, p < 0.001), with carbon stock increasing by 3.56 t C ha⁻¹ for each 1 m² ha⁻¹ rise in basal area. No significant differences in AGC were found across districts or community forests. Species diversity indices showed weak or non-significant relationships with AGC. These results show that the amount of carbon stored in ISS-managed Sal forests is mostly affected by the structure of the trees and the presence of large trees, not by the number of different species. So, when managing ISS-managed Sal forests, the focus should be on keeping large-diameter trees and making the structure of the trees more complex, while also keeping the number of different species to help the ecosystem stay strong and store carbon over time. A thesis submitted in patial fulfillment of the requirements for the degree of Master of Science in Natural Resources Management Thesis (M. Sc.) - Asian Institute of Technology, 2026 Forest management Nepal Carbon sequestration Nepal Asian Institute of Technology. http://203.159.5.9/ait-thesis/detail.php?q=B24140 http://203.159.5.9/ait-thesis/detail.php?q=B24140 260514 20260818221936.0