Limits are a key element in permaculture design.
At present the main work related to limits is based on the development of windbreaks and delimitation of the zones according to the permaculture vision.
Windbreaks are extremely important. Not only do they help in the creation of microclimates, they reduce the currents of hot and dry summer air that in our climate completely dehydrate the plants but also allow that in the winter the cold air does not the gele, helping in the formation of frost less intense. They can also be a good refuge for many small animals and insects, increasing diversity and thus benefiting the entire ecosystem that constitutes the farm and the area.
A windbreaker is itself a universe, a great project, where concepts such as multifunctionality and natural succession are present or can be applied. In our case, we are working on a general windbreak on the northern edge of the farm, where summer winds prevail and a local windbreaker in the short-term garden.
A windbreaker should not be a wall, even a tree, for example a wall of cypresses. This is due to air dynamic phenomena which, when struck by a vertical structure, suddenly changes direction, accelerating upward, and then entering the fifth from above and possibly with more force. It would be wrong to think that the moving air would go to the wall. Thus, a windbreak must be designed in the form of a ramp so that the air in movement can gradually change direction by passing over the space to be protected. There is a well-known relationship between height and breadth of the windbreak and the consequently protected area. However, due to the way the territory is divided into smaller properties, it is not always possible to implement an optimal ramp scheme. This is our case. So the option is at least to develop a windbreaker with a lot of diversity between evergreen trees and shrubs.
As perennial species, we use the existing cork oaks, the medronheiro, the laurel, the giesta, the olive tree in a shrub (preferably the zambujeiro), tagasaste (Chamaecytisus prolifer), rosemary, myrtle, lavender, durillo (Viburnum tinus), etc. With this composition we create a mixed windbreaker with irregular shapes.