Lowering wind speeds over manure storage areas allows for slower release of the odor plumes. Shelterbelts are an excellent way to block the wind and deflect and lift the air odor plumes. When building a shelterbelt, a minimum of 2 rows of trees or shrubs should be planted, with wedge-shaped ones that face prevailing winds creating the most turbulence. Planting fast-growing species will also give height to the plumes more quickly.
Tall barriers around manure lagoons can reduce downwind lagoon odor emissions by 26 and 92%. The horizontal extent of wind protection is proportional to the height of the shelterbelt. Wind speed reduction on the windward side of shelterbelts has been recorded at 2 to 5 H of the shelterbelt and on the leeward side, typical reductions are 30H. As porosity of the shelterbelt decreases to less than 50%, the greater the turbulence in the turbulent zone in which much of the dilution of the odor takes place. Porosity can be manipulated by spacing and species. Deciduous trees tend to create more open shelterbelts near the ground compared with conifer shelterbelts. A 1984 study found that a forest cleans the air of microparticles 20 times better than barren land. Leaves with large circumferences collect these particles better than simple-shaped leaves, suggesting that conifers may trap particles more effectively than deciduous trees and shrubs.