Growth Performance and Biomass of Selected Indigenous Tree Species in the Permanent Nursery, Addis Zemen, Northwest Ethiopia

The production of seedlings from selected indigenous tree species is influenced by the type of potting media and soil ratios. A nursery experiment was conducted in the Libo Kemekem District of Addis Zemen, northwest Ethiopia, to assess the growth performance and biomass of Olea africana, Albizia gummifera, Cordia africana, Millettia ferruginea, and Grewia ferruginea. Seeds were initially sown in seedbeds and later transplanted into polythene pots of varying sizes (8, 10, and 12 cm in diameter) filled with a mixture of forest soil, farmyard manure, and fine sand in three different ratios (3:3:1, 3:2:1, and 3:1:1). A factorial experiment using a randomized complete block design with three replications was implemented. Growth and biomass data were analyzed using the general linear model in SPSS software (Version 26). Significant variations were observed in root collar diameter and shoot height among potting media, pot sizes, and their interactions at level of 0.05 but not in shoot and root biomass. The most vigorous seedlings of G. ferruginea, C. africana, M. ferruginea, A. gummifera, and Olea europaea thrived in a 3:3:1 soil ratio with a 12‐cm pot size. While shoot and root dry weights showed minimal variation across treatments, M. ferruginea excelled in the 3:3:1 mixture and 12‐cm size. The findings indicate that the growth performance of indigenous tree seedlings is significantly influenced by the composition of potting media and pot size. The optimal mixture of forest soil, farmyard manure, and fine sand, particularly with a higher proportion of organic matter, enhances seedling vigor. Therefore, selecting the right substrate is crucial for enhancing the growth of indigenous tree species in nursery settings, thereby contributing to the restoration of degraded Afromontane forests.