Runoff management is an effective strategy to improve soil moisture and enhance plant growth in arid and semi-arid regions. This study quantitatively evaluated the impact of semi-circular bund systems on crown characteristics of three tree species- Prosopis cineraria (L.) Durce, Ziziphus spina-christi (L.) Willd, and Acacia ehrenbergiana Hayne or Vachellia flava (Forssk.) Kyal. & Boatwr.-in the Halvaei region of Minab County, Hormozgan Province, southern Iran. A factorial randomized complete block design was employed with two main factors: region (four levels: upstream, midstream, downstream within the treated area, and a control area without bunds) and tree species (three levels), with three replications. For each treatment combination, crown attributes were measured for 30 individual trees per species, totaling 540 trees. Two-way ANOVA followed by Duncan's post hoc test (α = 0.05) revealed that the bund treatment significantly (p < 0.01) improved all crown components except crown thickness. Mean tree height in the treated area (7.3 ± 2.4 m) was significantly higher than in the control (2.9 ± 1.8 m), representing a 27% increase. P. cineraria exhibited the greatest crown volume (14.8 ± 3.6 m³), while Z. spina-christi showed the largest crown diameter (4.1 ± 0.4 m) and crown area (12.2 ± 3.1 m²). A. ehrenbergiana displayed the lowest improvement in all measured traits. No significant differences were observed among upstream, midstream, and downstream positions within the treated area. In summary, the semi-circular bund system, when selecting the appropriate species based on the growth strategy, can be used as a low-cost and effective solution for restoring dry ecosystems in southern Iran.