On a 2000 square metre block in Moruya, NSW, I’ve been exploring growing different types of vegetation. As well as traditional shrub beds, mown grass, vegetable gardens, water harvesting ponds and a large outdoor courtyard I’ve planted a micro-forest and a Food forest.
Micro-forests cool the landscape
In 2019, I created pilot urban landscape project, called the Downer micro-forest. The pilot used dense planting, climate-ready trees and provides a cool space for the public to enjoy.
The Federal Labor Member for Canberra, Alicia Payne cottoned on to the idea. She invited the Molonglo Conservation Group and The Climate Factory to submit a grant application to build a micro-forest in her electorate. The Sullivans Ck micro-forest was borne.
Australia’s National Forest Inventory
The Federal Department of Agriculture describes forests as areas dominated by trees, usually with a single stem and a mature height exceeding two metres. The crowns of trees have the potential to cover 20% of the area.
They say,”Native forests are categorised in Australia’s National Forest Inventory into eight national forest types named after their key genus or structural form: Acacia, Callitris, Casuarina, Eucalypt, Mangrove, Melaleuca, Rainforest, and Other native forest (which includes a range of minor native forest types that are named after their dominant genera, including Agonis, Atalaya, Banksia, Hakea, Grevillea, Heterodendron, Leptospermum, Lophostemon and Syncarpia).”
“Across the wide range of rainfall and soil conditions that support forest, most of Australia’s ‘Native forest’ category of forest is dominated by eucalypts (77%) and acacias (8%).”
A home micro-forest
In our home garden, I’ve planted our front garden into a dense native micro-forest. My aim was to mimic the look and feel of the heavily vegetated local sand dunes at Moruya Heads. And to create a windbreak from hot westerly winds, provide privacy and make wildlife habitat.
To establish a dense privacy screen and windbreak I planted the fast growing local coastal wattle, Acacia longifolia subsp sophorae. Amongst these wattles, I peppered local tree species like Casuarina glauca, Allocasuarina, Callitris rhomboidea, Acacia mearnsii (Black Wattle) and Acacia fimbriata. The coastal wattle and Black Wattle grew to four metres high in three years. And some of the Casuarina outstripped the wattles.
Understorey shrubs include, Banksia integrifolia (Coastal Banksia), Leptospermum petersonii (Lemon-scented Tea Tree), Correa alba, Westringia ‘Wynyabbie Gem‘ and strappy plants like Dianella and Lomandra. Groundcovers include Myoporum parvifolium (Creeping boobialla), Carpobrotus (Pig Face) and Hardenbergia. Hardenbergia also known as Native sarsparilla, can grow as a sprawling groundcover or twine up trees and shrubs.
The native groundcover, Dichondra repens (Kidney Weed) grows naturally in the damp and shaded parts of the micro-forest.
Wildlife habitat
With the micro-forest or tiny forest, the aim is to make it as dense as possible and to avoid bare ground. We plant at a ratio of between three to four plants per square metre.
Local Blue-tongues took up residence in 2018. They provide an excellent service, munching on unwelcome snails.
In November 2019, I spotted my first pair of bumbling metallic green Carpenter Bees (Xylocopa) gathering pollen from Dianella and Westringia flowers. The dense shrubs are visited by small birds like Silver Eyes.
Soil improvement and irrigation
With soil excavated from our building site, our contractor, manipulated the ground to look like sand dunes. In each plant hole, I added organic material to give plants the best possible start to life.
In its first three years, the micro-forest survived on rainfall and occasional hand watering. Then, the summer of 2019 hit. By the year’s end Moruya received a paltry 508mm of rain (about 5/8ths) of the ‘average’ annual rainfall. Over summer 2019/2020 firestorms devastasted the Eurobodalla area, burning almost 80% of the landscape.
As a smokey January 2020 unravelled I questioned whether I’d made the right choice in planting a native micro-forest so close to our house. Our micro-forest faces west and if the fire reached us, the front garden would go up like kerosene on a barbie.
My partner and I, discussed hacking the trees off. But where would we place the prunings?
Late in January 2020, the fire burned to Moruya’s fringes. Luckily it didn’t penetrate into town. Since then, I’ve installed a 50m length of drip irrigation pipe to keep the micro-forest moist in hot weather. In addition, we are installing a second large water tank to protect the garden and house in case of fire.
Resources
Since penning this article, I’ve created a 54 minute video addressing frequently asked questions on how to make a home micro-forest.
Home food forest
As the name implies, the main aim of a food forest is to grow a diverse range of food in a forest-like environment. So while an orchard is a simplified forest, consisting of an over-storey that bears fruit, a food forest includes multiple vegetation layers. Like a micro-forest it includes groundcover layers that cool the soil (and provide habitat), shrubs, grasses, climbers and trees.
Improving the soil with organic material
In 2019 I chose a spot with alluvial soil, near Racecourse Creek, an ephemeral creek. Sometimes the creek is dry for months at a time, like in 2019 and sometimes it floods.
I marked out a 5m x 5m area for the food forest. Then I relocated the chooks to this space for a couple of months to scratch and fertilise the soil. I also added compost, seaweed and coffee grounds (from a local cafe). Our next door neighbour, a market gardener, formed five mounds with his cultivator.
Like the micro-forest I planted Wattles like Acacia floribunda that would grow quickly and protect sensitive plants. An added benefit of wattles is they drop leaves forming a fine mulch layer and add nitrogen to the soil.
Edible plants
I planted tubestock of edible exotic trees into the mounds: five carobs, three figs and one Mulberry. Shrubs include the Hawaiian Guava (Psidium guajava), Tamarillo (grown from a neighbour’s seed) and Peppino. Understorey plants include Comfrey (non-edible but a compost accelerant), Raspberry and Lemon Grass and rambling pumpkins and sweet potato.
Bush foods
I added tough local Warrigal greens, Tetragonia tetragonoides to the food forest. These plants grow exposed to salt laden winds at the beach and as a groundcover in Casuarina glauca forests. Warrigal greens need to be cooked prior to eating to remove oxalates. I combine them with silver beet and kale when I want to add some greens to a dish.
I also added one Davidson’s Plum, Davidsonia. These trees grow in Australian rainforests and require frost protection. They bare edible fruit which is apparently best stewed.
Maintenance
The biggest maintenance issue, for both the micro-forest and the food forest is keeping grasses like Kikuyu and Couch at bay. I’ve almost won the battle with our micro-forest. I find hand weeding enveloped by greenery meditative.
Cool haven
Once the trees canopies overlap in our food forest, a small spot for a comfy chair will be the perfect antidote to oppressive summer heat.
Holt Micro-forest and food forest
In 2021, I started working with a group of residents from Holt in the ACT. The group are on target to build a 1500 plant micro-forest and a food forest in 2022.
Postscript
January 2020 was followed by two years of La Nina bringing extreme rainfall. Our micro-forest is thriving while the back garden and food forest is soggy. These climatic extremes illustrate the need to prepare for the future – for drought, bushfire and flood.
