Plants, with their ability
to convert sunlight, water and nutrients to biomass, are the food
base for the varied forms of animal life. Humans, sitting high
on the food web, are directly or indirectly connected to the plant
kingdom for sustenance. Plants provide primary shelter or building
materials to many animal species.
Plants are used in permaculture in a variety of ways:
The least intensive form of use is to collect the products
of plants growing unattended in the wild. Plants for food, fiber,
medicine, flavoring, clothing and implements may be found easily
in most landscapes. Even in urban areas, the plants growing in
unattended 'wild' places may offer a bounty of products.
Plants may be used for windbreaks, sun traps, visual screening,
solar shading, water flow control and other such functions on
a site. Usually, when used in this manner, we try to select plants
that provide other uses as well.
Growing of plants for food, fiber or building materials is
a major component of permaculture. Cultivation may be intensive,
as in an herb garden close to a home, or relatively low care,
as in a nut orchard placed near a woodland. A design may incorporate
greenhouses, water gardens, keyhole gardens, trellises, and a
range of other plantings for productive purposes. The plants themselves
may require pruning, pleaching and other forms of care.
A healthy permaculture landscape contains animals as well as
plants. Planting to provide habitat and food for beneficial insects,
birds, wild and domestic animals may be part of the design. Aquaculture
may be included.
All plants provide organic matter that may be returned to the
soil. Some plants, however, go further and have the ability to
add nitrogen. These are particularly useful for improving the
soil for other plants. Plant roots help keep the soil loose and
some form symbiotic relationships with helpful subsurface fungi,
algae or bacteria.
Notes on Cultivation
Cultivation may increase erosion and loss of soil moisture as
soil particle surface is exposed to air. Forms of cultivation
that avoid plowing and turning over of the earth will be more
conservative of soil and soil moisture. Sheet mulching is one
approach to creation of a suitable planting medium without disturbing
the soil. Cultivation and intensive planting often leads to a
need to adjust to plant predators. The first line of defense is
to use a 'pest avoidance' approach by planting plants that take
care of themselves. Diversity of plants provides a habitat where
'pests' and 'desirables' are kept in balance and the insects and
diseases attacking plants are kept under natural control. Companion
planting may provide natural repellents to keep insects away from
food producing plants.
A Word on Trees
Trees are one of the most important plant types on Earth. They
increase precipitation, modify temperature, greatly reduce run-off,
filter air and sediments, reach into and loosen soil, protect
against wind and produce diversified environments. A healthy forest
will have many layers and different animals and birds will live
at each level.
Clearing of land for agriculture and grazing, and clear cutting
for pulp and wood products has greatly reduced the tree cover
on Earth. Reestablishing forests and planting of trees should
be high on a permaculture design agenda.
Forest restoration and ecoforestry practices allow wood products
to be harvested without destroying wildlife, recreation and other
values of forest habitats.