Page 18 - Issue-137

FEATURE

URBAN FOOD FORESTS:

AGRO-ECOLOGy ANd OTHER EdIBLES

By Dr Jonathan Foley

The idea of food forests is as old as agriculture itself. Early man felled ancient forests
to clear space for planting crops in the so called ‘slash and burn’ method. Once
trees were ‘chopped and dropped’ they were then burned, thus releasing carbon
into the atmosphere and storing nitrogen in the soil. Crops grew well for the first

few seasons due to this enrichment of the soil and then agrarian man created more
clearings in the forest, repeating the process.

adly, the scale at which this is taking
place in the 21st century is destroying
Stropical forests at an alarming rate.
Biologists report that every day, 100 acres
of tropical rain forest are cleared for logging
operations, agriculture or oil exploration.
Tropical rain forests that once covered about
20 percent of Earth’s surface now cover only
about seven percent.
On the east coast of Africa, the situation
is a little more hopeful; Kenya has become
a nation of tree planters inspired by
Nobel prize winner and late eco warrior
Wangari Maathai. Under her leadership,
the Greenbelt movement planted over 30
million trees. Rather than going along with
commercial ‘super agriculture’ methods,
Kenyan universities and agricultural
extension offices today advocate an agro-
forestry approach, mixing local trees with
agricultural crops. This concept is now
being championed globally by Geoff
Lawton in New Zealand, who is building
on permaculture (sustainable agriculture)
ideas expressed by Bill Mollison in the 70’s. Artocarpus heterophyllus or Jackfruit is one of the largest of edible forest fruits. treesplanet.blogspot.com
This article examines some of the key
benefits of urban food gardens, also showing
how to establish your own forest. canopy tree such as a Pecan nut tree, while a Comfrey or knit bone is one such herb. Its
root crop could be Cassava (yams) or onions leaves make excellent compost and their
What exactly is a food forest? and carrots. light grey colour mixes well with most
Food forests are a self-regulating and flowers.
low maintenance, sustainable form of Soil conditioning
plant-based agriculture. More practically Nitrogen (which makes for leafy plant Change over time
termed ‘agroforestry’ it is a system based growth) is locked up in larger trees which Forests are themselves created over time
on woodland ecosystems, incorporating often grow in sandy soils. In the roots by what we call pioneer trees (Acacia,
fruit and nut trees, shrubs, herbs, vines and of large, leguminous trees (for example Pigeon wood and Coastal gold leaf) which
perennial vegetables which have yields Acacia/ Vallochia), bacteria called rhizobia are generally fast growers but short-lived.
directly useful to humans, whilst working in release nitrogen into the soil where it is They provide shelter for the saplings of
harmony with nature. taken up by the other understory plants longer-lived trees such as yellowwoods. In
in an endless cycle of soil enrichment. natural forests, the larger trees decay and
Designing and creating a food forest These plants are called nitrogen fixers and die over time, thus creating more clearings
Layers in the forest may be trees, vines, groundcovers or even and light for their competitors and new
Lawton identifies seven layers of forest vegetables and herbs. So instead of the plants. The decay process involves the
vegetation ranging from the tallest high fertiliser inputs required in traditional breakdown of woody matter and cellulose
emergent canopy species to the lowest agriculture, food forests make use of natural by ants and bacteria, again releasing the
understory layer of herbs, grass and root soil conditioning. original nutrients and elements back into
crops. In between are smaller shrubs, trees Some herbal plants are extremely the soil. Over time there will be a shift from
and vines. Food forests use this concept effective in recycling plant nutrients and pioneer support species (such as legumes)
and substitute different agricultural crops making them available to other plants. which initially made up 95% of the forest, to
for each layer. An example would be a large These are called dynamic accumulators. productive species and agricultural crops.

16 Landscape SA • Issue 137 2024 Check us out www.salandscape.co.za