Shelterbelts and windbreaks: principles for installation

Wind can affect crops and animals, by directly or indirectly acting on mechanical or physiological processes related to microclimate and soil. There are several tree elements that, when correctly planed, allow the reduction of these effects. At the landscape level, most of the time they are used in combination with each other to reduce wind damage. According to their structure three types of green barriers may be considered (Pavari 1961): 1) shelterbelts - strips of wide multiple rows of trees or shrubs; 2) windbreaks - afforestation with single or multiple rows of trees (up to 4 or 6 maximum); 3) single hedges - single linear elements for the immediate protection of crops, composed by trees, shrubs or other