What changes at year five
The planting is done. The forest is now in charge.
By year five the chestnuts are 4 to 6 m tall. The apples are bearing. The currants and rhubarb under them have closed ranks across the ground. The job stops being "establish a system" and starts being "steward one."
This is the longest phase. Decades. If you planted at 35 you will be tending this same forest at 75. For the years before this point, see Food Forest Design.
Canopy management
A food forest closes its canopy somewhere between year six and year ten. Once it closes, the understory starts to fail.
Aim for 60 to 70 percent canopy cover. Measured from below in summer, looking up. Below 60 percent and the system burns too much sun, dries out, and weeds come back hard. Above 70 percent and the gooseberries stop fruiting, the herbs go leggy, and the strawberries vanish.
You hit that target with three cuts.
Crown thinning on the overstory fruit and nut trees. Take out crossing branches, inward growth, and the densest 20 percent of the upper crown every three years. Light reaches deeper without losing fruiting wood. See Pruning Basics and Aged Orchard Rejuvenation.
Coppice on the support species. Alder, hazel, willow, and most nitrogen-fixers regrow from a cut stump. A rotation on a 5 to 8 year cycle keeps them productive and short. See Coppice Rotation.
Pollarding for street-side or boundary trees that need a fixed ceiling. Cut above browse height, let it regrow, repeat every two to four years.
Do this in the dormant season. Mark the cuts you plan to make before the leaves drop. By February it is too easy to overcut.
The nitrogen-fixer rotation
The support trees were planted to fail.
Inga edulis, honey locust (Gleditsia triacanthos), black locust (Robinia pseudoacacia), alder (Alnus glutinosa), Siberian pea shrub: these were scaffolding. They held the soil, pumped nitrogen into the ground, and shaded out grass while the apples and chestnuts found their feet.
Every three to five years, chop-and-drop a third of them. Cut at knee height. Leave the trunk to resprout. Lay the branches across the ground as mulch where the system needs them. See Chop-and-Drop and Nitrogen-Fixing Trees and Plants.
Two things happen.
The first is nitrogen release. When you cut a nitrogen-fixer the root nodules die back. They decompose in the soil and dump roughly 40 to 80 kg of nitrogen per hectare over the following season. The fruit trees lift visibly.
The second is light. The gap opens a column of sun the understory has been starving for. Currants flower harder. Herbs come back. Self-seeding annuals like calendula and borage re-establish.
Rotate the cuts. A third this year, a third in three years, a third in three more.
Gap dynamics
A tree will die. Usually unexpectedly.
A storm takes the old plum. Fireblight finishes a pear. A grafted apple gives up at year eighteen. The gap opens, light pours in, and within one season the brambles and grass will own that patch if you do nothing.
Plan the replacement before the gap opens. Walk the forest in winter and name your weakest five trees. For each one, decide what you would plant if it failed this year. Have the seedling on hand or know the source. See Succession Planting.
The replacement is usually not the same species. Conditions at year fifteen are not the conditions at year one. The new tree goes in with more shade tolerance than the original. A failed apple becomes a medlar. A failed Inga becomes a more permanent canopy tree.
Fill the gap fast. Plant within the same season. Protect the new tree. The deer have been waiting.
Mulch and the soil
The mulch layer is the engine.
Top it up once a year. 5 to 8 cm of wood chip, straw, or chopped support-species biomass spread out to the drip line of every productive tree. Done in autumn this feeds the soil over winter and beats the spring weed flush. See Soil Cover and Long-Term Soil Care.
If you cut your nitrogen-fixers in spring, that biomass is your mulch. The system feeds itself. You should not be hauling in many inputs by year eight.
Do not strip the ground. Leaf litter under fruit trees is not mess. It is the soil food web eating breakfast.
Browsing pressure
Deer, rabbits, and voles eat the regenerating layer.
The mature trees are safe. The new ones replacing the gaps are not. Anything under 1.5 m is at deer height. Anything green at ground level is rabbit lunch. The regenerating understory after a chop-and-drop is the most vulnerable layer in the whole forest.
Tube or cage every new tree for the first three years. 1.2 m mesh tubes for deer country. Wire collars sunk 10 cm into the soil for voles. See Site Protection and Deer and Rabbits.
A whole gap planting can fail in one winter if you skip this step. The deer find your replacements before you do.
The temptation to tidy
Most food forests are over-tidied to death.
Leaf litter feeds the fungi that feed the trees. Dead wood holds beetle larvae that feed the birds that eat your pest caterpillars. The bramble at the wet corner shelters the slow worm that eats your slugs. The ivy on the dead trunk is the last nectar source in October. See Dead Wood Habitat and Rewilding Edges.
Pick one cleared zone for the paths and the harvest beds. Let the rest be a forest. Walk it weekly. Carry secateurs and a notebook, not a strimmer.
The work after year five is mostly looking. See Observation First. Most days you decide what not to do, then you do that. The trees handle the rest.