Micro-forest vs Food forest – what’s the difference?

On a 2000 square metre block of land in Moruya, NSW, I’ve been exploring growing different types of vegetation with different purposes. As well as traditional shrub beds, mown grass, vegetable gardens, water harvesting ponds and a large outdoor courtyard I’ve also planted a micro-forest and a Food forest.

In 2019, I coined the term ‘micro-forest’ to refer to a dense area of climate-ready vegetation that cools the landscape, provides habitat and provides hope for the future. I used the term specifically to describe a pilot urban landscape project I was spearheading in Canberra – the Downer micro-forest that would use climate-ready trees – trees, able to cope with a hotter and drier future and provide a cooling space within.

The Federal Labor Member for Canberra, Alicia Payne liked the idea so much that she invited the Molonglo Conservation Group and The Climate Factory to submit a grant application to build a micro-forest in her electorate – hence the Sullivans Ck micro-forest was borne.

The Federal Department of Agriculture describes forests as areas dominated by trees, usually with a single stem and a mature height exceeding two metres and with the potential tree crown covering 20% of the area.

“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%).”

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 undulating heavily vegetated local sand dunes at Moruya Heads. And to create a windbreak filtering hot westerly winds, provide privacy from a busy street and create wildlife habitat.

The micro-forest grew quickly to provide a dense windbreak, privacy screen and wildlife refuge in 3 years.

Using the fast growing local coastal wattle, Acacia longifolia subsp sophorae I quickly established a dense privacy screen and windbreak. Amongst these wattles, I peppered local tree species like Casuarina glauca, Allocasuarina, Callitris rhomboidea, Acacia mearnsii and Acacia fimbriata. The coastal wattle and Acacia mearsnii (Black Wattle) have grown rapidly to at least 4 metres in 3 years, whilst some of the Casuarinas have outstripped the wattles.

Understorey shrubs include, Banksia integrifolia (Coastal Banksia), Leptospermum (Tea Tree), Correa alba, Westringia ‘Wynyabbie Gem’ as well as strappy plants like Dianella and Lomandra. Groundcovers include Myoporum parvifolium, Carpobrotus (Pig Face) and Hardenbergia. Hardenbergia also known as Native sarsparilla and widely cultivated, can grow as a sprawling groundcover or twine up trees and shrubs.

The native groundcover, Dichondra repens (Kidney Weed) makes its presence felt in shadier moister parts of the micro-forest.

A couple of edibles have crept into the micro-forest, a Macadamia (a native of Australian rainforests) and a grafted Avocado (non-native). Time will tell if they bare fruit. And a Grevillea robusta (Silky oak) seedling has self-sown amongst Allocasuarina trees. It’s staying for now.

Not all the plants have survived, the coastal wattles are short-lived – when they grow quickly they tend to die quickly. Cutting them back seems to extend their lives. In dry periods the Casuarinas, Allocasuarinas and Wattles drop leaves adding to leave litter below.

The aim is to make the planting as dense as possible and to avoid bare ground. Local Blue-tongues appreciate my efforts and took up residence in 2018. In November 2019, I spotted my first pair of bumbling metallic green Carpenter Bees (Xylocopa) gathering pollen from Dianella and Westringia flowers.

This Blue-tongue lizard lives in the dense undergrowth of our micro-forest. I was quite surprised when I threw some snails near it and it started eating them and was lucky enough to capture it on video!

Our dense front planting provides a great foraging spot for small birds like Silver Eyes as they cross our block onto other places.

With soil excavated from our site cut, our earthworks contractor, placed soil to look like sand dunes. For every hole I dug for tubestock, I added organics to give plants the best possible start to life.

For its first three years, the micro-forest survived mostly on rainfall and occasional hand watering. Then, the summer of 2019 hit. By the year’s end Moruya had received a paltry 508mm of rain (about 5/8ths) of an ‘average’ year, then firestorms devastasted the Eurobodalla area (burning almost 80% of the landscape).

As a smokey January unravelled I began to question whether I’d made the right choice in planting the micro-forest. It is to the west and if the fires reached us, the front garden would burn like kerosene thrown on a barbie.

My partner and I, discussed hacking the trees off – but then what would we do with all the prunings?

Late in January 2020, the fire reached the town’s fringes, luckily it didn’t penetrate into the urban parts. Since then, I’ve installed a 50m length of drip irrigation pipe to try and keep the micro-forest slightly moist in hot weather. Who knows what this summer will bring.

Being on a large block – 2000 square metres or half an acre, gives me scope for experimenting with landscape ideas. While we grow vegetables and herbs in garden beds, I was attracted by the idea of creating a 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 could be thought of as a highly simplified forest, consisting of fundamentally the over-storey that bears the fruit, a Food forest includes lots of vegetation layers that produce food. Like the micro-forest it includes groundcover layers that cool the soil (and provide habitat), shrubs, grasses, climbers and trees.

In 2019 I chose a spot with good alluvial soil, near our ephemeral creek but hopefully above the floods (fingers crossed). I marked out a 5m x 5m area and allowed the chooks a couple of months to scratch the ground up and fertilise the soil. I also added compost, seaweed and coffee grounds. Our next door neighbour, a market gardener, formed five mounds and furrows with his cultivator.

Like the micro-forest I’ve planted a couple of fast-growing wattles (Acacia floribunda) that will grow quickly and help protect the more sensitive plants. They’ll also drop leaves helping to form a mulch layer and add nitrogen to the soil.

I planted tubestock of the following edible trees into the mounds: 5 carobs, 3 figs, 1 Davidson’s Plum (an edible tree of rainforest) and 1 Mulberry. Shrubs include the Hawaiian Guava (Psidium guajava), Tamarillo (grown from a neighbour’s seed) and Peppino. Understorey plants include Comfrey (not edible but known as a compost accelerant), Raspberry, Eggplants, Capsicum and Lemon Grass and rambling pumpkins and sweet potato. Herbs like parsely and dill have quickly reproduced filling in gaps.

To cover the soil quickly, I introduce the fast growing and tough native bush food, Pigface (the fruits and leaves are edible) and the locally occuring Warrigal greens created a green carpet over the ground. The Warrigal greens are a pioneer plant and if conditions are right will seed prolifically – giving you greens all year round in our area.

The Food forest survived the 200mm of rain we received in February 2020. Planting trees on the mounds probably saved them from being killed by waterlogging.

The Food Forest was just above the flood on Racecourse Creek in February 2020. We received around 200mm of rain over 10 days. The flood took down fences and washed away vegetables in the next door market garden.

Autumn is often a time of abundance. In the foreground is the large-leaved Tamarillo. Pumpkin and Sweet Potato jostle with one another for space.

The biggest maintenance issues, for both the micro-forest and the Food forest is keeping the vigorous grass (Kikuyu) at bay. I’ve almost won the battle with the micro-forest having spent many hours hand weeding its vigorous runners whilst refusing to use herbicides.

Because I have a large garden, I haven’t made spaces within these forests to keep us cool in hot weather – that’s because there’s other spots in the garden, like our micro-oasis adjacent to the house that I’m focusing my efforts on.

However, once the trees grow taller in the food forest and their canopies start to overlap, a small spot for a comfy chair will be the perfect antidote to oppressive heat.

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