Shelter efficiency of windbreak influenced by stand configuration

Stand density and planting point configuration are two critical parameters influencing windbreak efficiency. This study investigates how stand density and triangular planting point configurations affect wind speed in Haloxylon ammodendron windbreaks. Wind tunnel experiments were conducted on four windbreaks with varying dimensions: A (17 cm × 17 cm), B₁ (17 cm × 34 cm), B₂ (34 cm × 17 cm), and C (34 cm × 34 cm), corresponding to field densities of 1500, 750, 750, and 375 plants·ha⁻¹, which also represented the planting density, reserved density and natural vegetation density of H. ammodendron, respectively. Results showed faster wind speed variation near windbreaks with higher densities, with windbreak B₁ (row spacing > plant spacing) exhibiting faster variation than B₂ (plant spacing > row spacing). The area of weak wind speed (U/U₀ < 0.5) around B₁ was approximately three times that of B₂. Wind reductions downstream the windbreaks were not proportional to stand density, with ratios of A:B:C ≈ 6:3:2. The position of U_min moved further leeward as stand density decreased, accompanied by an increase in U_min values. These results highlight the significant influence of both stand density and planting point configuration on windbreak efficiency, offering valuable insights for optimising windbreak design in arid regions.