Abstract On-farm tree planting is a widely practiced agroforestry strategy that enhances soil productivity, supports rural livelihood, and contributes to climate resilience. However, the diversity of on-farm tree assemblages and the socio-economic factors shaping farmers’ planting decisions remain poorly documented in Nepal’s lowland Terai region. This study aimed to (1) quantify tree species richness, evenness, and dominance across four planting contexts; home gardens, woodlots, farm boundaries, and intercrops and, (2) identify the demographic and socio-economic determinants associated with on-farm tree growing. Field inventory of farmland trees and household socio-economic surveys were conducted in Ward 3 of Kawasoti Municipality, Nawalparasi (East of Bardaghat Susta) district, Nepal. Tree diversity was assessed using the Shannon–Wiener index (H′), Simpson’s dominance (D), and Pielou’s evenness (J′). Binary logistic regression modeled the presence of on-farm trees against 15 socio-economic predictors. We recorded 2,350 trees across 36 species and 18 families, with Melia azedarach and Tectona grandis being the most abundant species. Overall farmland planting has moderate diversity (H′ = 2.10; J′ = 0.59; D = 0.20). Among four planting context home gardens exhibited the highest species richness, while intercrops showed the greatest tree abundance. Logistic regression revealed five significant predictors of tree presence: agroforestry extension (OR = 41.1), male-headed households (OR = 2.67), livestock units (OR = 1.49 per LSU), farm size (OR = 1.09 per 0.0338 ha), and fuelwood consumption (OR = 1.01 per 30 kg)). Diverse planting contexts maintain tree species richness and abundance, with home gardens as biodiversity hotspots and intercrops boosting tree numbers. These patterns indicate that farmers strategically allocate species based on space availability, household needs, and management priorities. Strengthening extension, addressing gender disparities, and aligning agroforestry practices with household needs can advance the development of multifunctional and species-rich agroforestry systems in in Nepal’s Terai.
Bhattarai et al. (Thu,) studied this question.