Perennial plantings serve many functions in permaculture gardens - they provide food, protect soils from erosion, rebuild soil fertility, serve as firewood or construction materials. Trees create shade and modify microclimate, around the home and within the garden, reducing water evaporation and/or overheating of buildings. Trees aid in preservation of biodiversity, provide habitat for birds and beneficial insects. Many fruit trees aid families in getting proper nutrition and in maintaining good health.