The Forest Gardener: Dan Harris-Pascal at TEDxCanberra (Full Transcript)

Dan Harris-Pascal – TRANSCRIPT

When I was asked to speak here at TEDx Canberra as a passionate ecologist and designer, I could not resist presenting on food production and particularly urban food production, an area whose future is uncharted. What is known about the future of food production, is that the quantity of food that we produce needs to markedly increase in order to meet the projected food needs for a growing population.

Unfortunately, in the past, increases of food production have come at the expense of ecosystems, as resources are diverted away from the environment and into agriculture. This is becoming an increasing issue given the range of ecosystem services which an intact ecology provides, including things like pollination, and the creation of soil. If we are going to be able to produce the food we need in the future, we need to do so in a way that supports and enhances ecosystems.

When I confronted this question a number of years ago, about how we could produce more food, I was passionately studying plant science and genetics. However the solutions on offer were more of the same and showed me a future where every forest was turned into a field and every river used for irrigation. Not feeling entirely comfortable with this vision of the future, I began to investigate the food production practices used by other cultures, to see if they could offer us any novel solutions. I was lucky enough to be selected to participate in a program at a botanic gardens in Hawaii.

I spent 3 months working with the gardens and investigating the food production practices used in ancient Hawaii. When anthropologists first began studying food production in Hawaii, they termed the Hawaiians as gardeners rather than farmers. The Hawaiians were gardeners because when they set out to discover the islands of Hawaii, they took with them in their canoes 30 species of plants. Upon arrival on the island, they were able to cultivate these 30 species of plants to grow almost everything that their civilization required.

The Hawaiians were gardeners because rather than just arbitrarily putting up paddocks on the island, they understood the island ecosystem, and how the different parts of the landscape interconnected. Food production in Hawaii was organized around the catchments. This is a cartoon from the Botanic Gardens where I worked. At the top of the catchment, the ecosystem was left intact to provide ecosystem services to the agriculture and food cultivation that occurred downstream. These services included crucial things like making it rain and filtering water.

Further down the catchment, the Hawaiians had an amazingly landscaped island, and they would cultivate in these areas taro and tree crops through an impressive system of aqueducts. However, when they returned the water that they used for irrigation, to the river, it was full of silt and very high in nutrients, and this could damage the reef which the Hawaiians relied upon to produce fish. The Hawaiians designed a solution around this, and would create a series of fish ponds at the mouth of each river and this turned those nutrients into another food yield.

I was amazed by the integrated food production systems which I saw present in ancient Hawaii, and couldn’t wait to get home and see if they would work here. But a seed of doubt crossed my mind; It was all well and good if this would work in the tropics, but I was planning to return to Canberra which as we felt over the winter months is a far cry from a tropical island.

Upon doing further research, I was pleased to find that there were a range of cultures from a range of different climates that utilized a form of food production that resembles gardening more than farming. One of the big myths of civilization is that people were hunter-gathers; one day discovered agriculture, and we never looked back. The reality is there is a third way, which was practiced by people around the world and more resembles gardening than farming. This is known to be older than agriculture and is today termed forest gardening. There are forest garden cultures from around the world, in Australia, Asia, Europe, Africa, and the Americas.

The best studied examples include the oak woodlands of California, the Araucanian Forests of Chile, dehesa systems in Mediterranean Europe and parts of the Amazon rainforest. What is amazing about these systems is that when Europeans encountered them, they first just thought they were wilderness, not realizing that they were actively cultivated by people. All of these cultures would cultivate the whole landscape, they were able to harvest from tree crops and because the ecosystem and the food production were tied together they were also able to raise livestock, undertake hunting, and wild harvesting.

Over the last 30 years, a range of people have been studying historical examples of forest gardening and scrutinizing them through the modern lenses of ecology, botany, and forestry. Lucky for us, the theory stacks up. It is possible to produce food and maintain ecosystem services, and it is possible to grow a range of plants together so they cooperate rather than compete.

Forest gardening today is not about a romantic return to the past, but rather a modernization of working examples from the past to provide for our needs in the future. I was swept up in forest gardening, I devour every book and every website I could find on it. I came to understand there are three key principles that make a really great forest garden. The first thing you need in a forest garden is you need perennial plants, plants which grow for more than one year.

Because perennial plants grow for more than one year, they tend to develop extensive root systems, which reach deep down into the soil, and enable them to access water and cycle nutrients. With these deep root systems, perennial plants form associations with soil microbes and things like earthworms, which we saw earlier. They create and cultivate a vibrant living soil food web, and this is able to support the perennial plants over time.

The second principle that we find in a forest garden is it is a polyculture, many different species of plants growing together. Now if we went out and randomly selected some plants and started growing them in the same space, it’s likely that we’d get competition as the plants would have similar needs. A forest garden gets around this through the use of layers. Because we select plants that have slightly different shapes and sizes, we are able to grow them in the same space without them competing too much.

In a forest garden, we can cultivate a canopy layer of fruit trees, shrubs below them, and even a layer of herbs below that. These systems become incredibly efficient because we are now gardening both horizontally and vertically, above and below ground. The third principle which we find in a forest garden is that a forest garden becomes a model ecosystem. An ecosystem is defined as the interactions between living and non-living elements in a system, and if we just took these plants and put them together in a garden, all we would have is a collection.

To be a model ecosystem, these plants need connection. To create connections in a forest garden, we need to use the workers of the forest. The bees, the birds, the insects, and the microbes that create the interactions that make a forest ecosystem abundant and resilient. We can easily do this in a forest garden, and the ecosystem that we create, can provide ecosystem services to all forms of production.

So, how do these principles work in practice? This is my friend Cam’s forest garden, and my friend Cam really wanted to grow peaches, so he planted a few peach trees. In order to produce a good crop of peaches, this tree needs access to nutrients, assistance in pollination, and protection from pests. Conventionally, nutrients would be provided to this tree through the use of synthetic fertilizers, but these are known to damage soil food web which this tree relies upon.

Pest control would be undertaken through the use of insecticides, but these are known to kill off the pollinators that the peach tree relies upon. In a forest garden, we are trying to use our layers and these connections to create associations between the plants and the forest garden. This is kind of like companion planting but on a much bigger scale. This peach tree is growing in association with plants that bring nitrogen and nutrients into the soil, plants which provide habitat for insect eating birds, and a range of herbs which provide flowers and food for pollinators throughout the year. It’s much easier for this peach tree to get the nutrients for the needs that it has, and it can produce many more peaches as a result. These ideas go beyond our backyard as an example of how forest gardening could apply to modern agriculture, I often think of the example of almond production in California.