Layer
A level of vegetation in a forest garden: tall tree, small tree, shrub, herbaceous, ground cover, root, climbing.
Explanation
The vertical stacking of layers uses the space in height and imitates the structure of a natural forest. A central concept of the forest garden, theorised by Robert Hart in England in the 1980s, then developed by Patrick Whitefield, Martin Crawford (Creating a Forest Garden, 2010) and Toby Hemenway.
Refined definition
The layers are the vertical levels of vegetation in an ecosystem. Robert Hart described seven storeys in his Wenlock Edge forest garden (Hart, Forest Gardening); John Kitsteiner proposes adding an aquatic layer and a fungal layer (Kitsteiner, 2013). In a natural forest, these layers coexist through adaptation to available light, those below tolerate the shade of those above. In a forest garden, we choose them for their productive complementarity: high fruit, mid-height berries, low perennial vegetables, roots, useful climbers.
Key points
The 7 classic layers
1. CANOPY: large fruit trees (walnut, chestnut, apple on standard rootstock). 2. LOW TREE LAYER: smaller fruit and nut trees, often on dwarfing rootstocks (dwarf pear, plum, apple on dwarfing rootstock, hazel). 3. SOFT-FRUIT SHRUBS: redcurrant, raspberry, blackcurrant. 4. HERBACEOUS PERENNIALS: comfrey, perennial sorrel, perennial kale. 5. GROUND COVER: strawberry, clover, nasturtium. 6. ROOT: dandelion, Jerusalem artichoke, parsnip. 7. CLIMBING: kiwi, vine, hop. Heights depend on the site and rootstocks: think in relative storeys rather than metres.
Why it works: tiered light
In a forest, each storey uses part of the light left by the storeys above. In the garden, we therefore choose for the lower storeys plants that tolerate the shade of the upper layers.
The edge effect and the margin
The transition zones between environments (forest/meadow edge, waterside, canopy edge) mix the conditions of two habitats and often host a wide diversity of species. Mollison makes it a design principle, the “edge effect”; its real effect varies with species (Ries et al., 2004). In a forest garden, we deliberately multiply these edges through cut-outs, gaps and curves rather than straight-line borders.
Watch out for
- • A forest garden takes several years to establish, patience needed. First year: the aesthetic shock of a “building-site” plot.
- • Suited mainly to humid temperate climates. In a dry Mediterranean climate, adapt with drought-tolerant species and greater distances between trees.
Sources
- Hart, R. (1996). Forest Gardening: Cultivating an Edible Landscape (2e éd.). Totnes : Green Books.
- Crawford, M. (2010). Creating a Forest Garden: Working with Nature to Grow Edible Crops. Totnes : Green Books.
- Hemenway, T. (2009). Gaia's Garden: A Guide to Home-Scale Permaculture (2e éd.). White River Junction : Chelsea Green.
- Ries, L., Fletcher, R.J., Battin, J. & Sisk, T.D. (2004). Ecological responses to habitat edges: mechanisms, models, and variability explained. Annual Review of Ecology, Evolution, and Systematics, 35, 491-522.
- Kitsteiner, J. (2013). Nine Layers of the Edible Forest Garden (Food Forest). Temperate Climate Permaculture (tcpermaculture.com), 27/05/2013.
- Mollison, B. (1988). Permaculture: A Designers' Manual. Tyalgum : Tagari Publications.
- Whitefield, P. (1996). How to Make a Forest Garden. East Meon : Permanent Publications.