for this reason the use of indigenous species should be increasingly considered this includes the supply of trees and control and care of plantations among the key priorities of tree planting are the creation of tree belts around cities large towns and populated centres the protection of installations infrastructure and agricultural lands from advancing sands the struggle against the destruction of river banks and against mud flows and efforts to check the salinization of soils from a silvicultural point of view planting areas are being landscaped soil is being prepared and water wells for the irrigation of trees are being drilled