Leaf harvesting intensity alters growth and functional traits of baobab (Adansonia digitata) in semi-arid West African systems

Baobab (Adansonia digitata) is a major species used against malnutrition and food insecurity in Africa. However, its population's sustainability is threatened by low natural regeneration and intensive exploitation of its parts for subsistence and commercial purposes. This study used a randomized complete block design to assess whether the intensity of leaf harvesting from baobab seedlings alters the growth and functional traits of baobab in semi-arid systems. Leaf harvest stress was applied with two levels: I50 (50%) and I75 (75%) from 30 to 90 d after transplanting (DAT). The results show that soil water content (SWC) significantly varied between harvesting intensities, among DAT, among radial distances (Rd), and for the interactions I × DAT and Rd × DAT (p < 0.001). The SWC was 0.52% lower under I50 compared to I75. Baobab growth parameters and biomass increased with rising DAT, with the highest average rate under I50. The leaf count and height significantly differed among DAT (p < 0.05), with a higher average growth rate of leaf count under I50 (62.1%). The average fresh biomass was 3.90% lower under I50 than under I75, and the dry biomass was 3.83% lower. Under I50, the soil water content correlated negatively with height, stem diameter, number of leaves, and fresh biomass, but positively with dry biomass. Given that 75% defoliation at 30-d intervals yielded optimal fresh leaf production, this harvesting regime is recommended for commercial baobab leaf production systems. However, long-term studies are required to assess the sustainability of this practice and its effects on plant resilience under fluctuating environmental conditions.