Food forest design: 7-layer principle
A food forest is an edible landscape designed to mimic the vertical and ecological structure of a natural forest, replacing the ornamental species of forest layers with productive edible or otherwise useful plants. The 7-layer model -- most commonly associated with Robert Hart's work in England in.
A food forest is an edible landscape designed to mimic the vertical and ecological structure of a natural forest, replacing the ornamental species of forest layers with productive edible or otherwise useful plants. The 7-layer model — most commonly associated with Robert Hart's work in England in the 1980s and popularized through permaculture literature — divides the food forest into vertical strata, each producing edible or functional yields.
Per University of Vermont Extension, food forests are a legitimate and increasingly studied agroforestry model with applications ranging from subsistence small farms to residential gardens.
The 7 layers
Per Hart's model and interpretations in permaculture literature, and per UVM Extension and USDA Agroforestry Research Trust materials:
Layer 1: Canopy (tall trees, 30—60+ ft)
High-canopy fruit and nut trees. These are the long-term yield layer.
Common choices for eastern North America:
- Juglans nigra (black walnut) — native; significant mast crop; allelopathic (suppresses some plants near roots); zones 4—9
- Carya illinoinensis (pecan) — zones 6—9; long-season nut crop; large tree (50—70 ft)
- Castanea (chestnut) — C. mollissima (Chinese chestnut) is blight-resistant; zones 4—8; per Cornell Extension, a productive and underused nut crop
- Quercus (edible acorn oaks) — most Quercus acorns require leaching but are edible; wildlife mast value is primary
Layer 2: Dwarf canopy (small trees, 15—30 ft)
Standard and semi-dwarf fruit trees.
Common choices:
- Apple (Malus) — multiple varieties for succession ripening; per Cornell Cooperative Extension, the most widely adapted fruit tree for eastern US
- Pear (Pyrus) — Asian and European types; disease-resistant varieties
- Plum (Prunus domestica, P. americana) — underused; productive; zones 4—9
- Persimmon (Diospyros virginiana) — native; very productive; deer browse the fallen fruit; zones 4—9
Layer 3: Shrub layer (3—15 ft)
Fruiting shrubs.
Common choices:
- Blueberry (Vaccinium corymbosum) — native; require acid soil (pH 4.5—5.5); per Penn State Extension, the most reliable small-fruit crop for eastern US
- Elderberry (Sambucus canadensis) — native; fast-growing; fruit for wine, syrups; zones 3—9
- Ribes (currant, gooseberry) — European black currant (R. nigrum) and American gooseberry (R. uva-crispa); zones 3—7
- Aronia (chokeberry) — native; very productive; astringent when raw but excellent dried/cooked; zones 3—8
- Viburnum trilobum (American cranberrybush) — native; edible fruit (tart); zones 2—7
Layer 4: Herbaceous layer (1—3 ft)
Edible perennial herbs and vegetables.
Common choices:
- Asparagus officinalis — perennial; zones 3—8; 3 years to first harvest
- Symphytum (comfrey) — dynamic accumulator; deep roots mine minerals; per Oregon State Extension, used as mulch/green manure; not recommended as food due to pyrrolizidine alkaloid content
- Allium spp. (walking onion, chives, garlic) — perennial alliums
- Levisticum officinale (lovage) — celery-flavored perennial herb; zones 3—8
Layer 5: Ground cover (0—12 in.)
Low edible plants.
Common choices:
- Strawberry (Fragaria × ananassa, F. vesca) — day-neutral or alpine varieties
- Gaultheria procumbens (wintergreen) — native; edible berries; ground cover
- Trifolium repens (white clover) — nitrogen fixer; nectar source; edible; often used as living mulch
- Thyme (Thymus spp.) — edible; drought tolerant; good path cover
Layer 6: Root layer (underground)
Plants producing edible underground portions.
Common choices:
- Stachys affinis (crosne, Chinese artichoke) — produces small edible tubers
- Helianthus tuberosus (Jerusalem artichoke, sunchoke) — native; very vigorous; produces edible tubers; per Illinois Extension, can become invasive in gardens; contain with barriers
- Potato (Solanum tuberosum) — annual root layer
- Dahlia — tuberous roots are edible (mild flavor)
Layer 7: Vertical / vine layer
Climbing productive plants.
Common choices:
- Kiwi (Actinidia arguta, hardy kiwi) — zones 4—8; per NC State Extension, produces small fruit in clusters; self-fertile varieties available
- Grape (Vitis spp.) — native species and cultivated hybrids; per Cornell Extension, important to choose disease-resistant varieties for humid eastern climates
- Hop (Humulus lupulus) — native; used in brewing; vigorous climber