Endangered coastal rainforest inspires the Moruya micro-forest

Moruya is a small regional New South Wales town, nestled between coast and hills. In 2016, my partner and I bought land in the town to build our first home and garden. As a landscape architect I was excited to experiment with plants I couldn’t grow in Canberra.

Canberra’s Micro-forests

I had spent the last 30 years living and working in Canberra. There I knew the local plant communities well. In 2019, after experiencing the hottest and driest year on record I started The Climate Factory. The goal was to build dense native plant pockets or micro-forests in public spaces to cool the landscape.

I was influenced by the Miyawaki method of organic soil preparation and dense planting. However, I didn’t follow the method strictly. The method calls for a natural forest community to be replicated in miniature.

In Canberra, I was hamstrung. Most forests surrounding Canberra are dominated by Eucalypts or Gum trees. I was sure planting Eucalypts in suburbia would alarm citizens due to their potential bushfire risk. Instead I chose small native trees with low flammability.

Black Summer Fires

2019, Australia’s hottest and driest year on record, culminated in the Black Summer fires. The fires burned 24 million hectares, killed 33 people and millions of animals.

Smoke in the sky above Gundary oval Moruya, 31 December 2019.

As 2019 drew to a close we watched as Moruya crackled. Rainforest species looked like skeletons as they dropped leaves in response to low rainfall levels. Tree fern fronds hung brown and limp. Fire ripped through the region burning everything in its path.

La Nina follows fires

Post fires we were graced with two periods of La Nina bringing wet weather. Much of the bush regenerated. After planning three micro-forests in Canberra I was ready for a new challenge. Why not build a micro-forest in Moruya and base it on a rainforest community?

Finding rainforest examples

In my research I came across a document describing endangered ecological communities of the Eurobodalla. Listed amongst them was Littoral or Coastal rainforest. I was intrigued.

Elkhorns are an epiphytic fern of coastal rainforest.

Coastal rainforest is defined as being within two kilometres of coastal influence. With the help of Local Land Services I started visiting pockets of rainforest. Eurobodalla Shire Council manages two portions of this ecological community, one at Tomakin the other at Tuross Head.

Chatham Park, Tuross Head

This 30 acre site is a delight. It was set aside by the land developer, Hector McWilliam for the community. It’s lush and green with small pathways winding through the dense vegetation, welcome signs and simple bridges. You can hear the ocean but can’t see it.

Coachwood, Ceratopetalum apetalum in Chatham Park, Tuross Head.

Within the park are rainforest trees like the striped-trunk Coachwood, Ceratopetalum apetalum and the fruit bearing Plum pine, Podocarpus elatus. And plenty of Yellow stringybark, Eucalyptus muellerana which grows along the south east NSW coast.

Gracing the trees are the ephiphytic fern, Elkhorn, Playtycerium bifurcatum. On the forest floor are a bevy of groundcovers, including Kidney Weed, Dichondra repens and ferns like the Maidenhair and Doodia aspera.

The hand carved signs are reminiscent of drawings from Winnie-the-Pooh.

Next steps for Moruya Micro-forest

What are the next steps? We need to find land to build our 1500 plant micro-forest. Ideally it will be around 1000 square metres in area and located within walking distance from the Moruya town centre.

Micro-forest a heat haven

The Moruya micro-forest will demonstrate the importance of endangered plant communities, like littoral rainforest. It will also act as an outdoor heat haven when hotter drier weather returns.

silver saltbush on the left contrasts with Warrigal greens

Ground covers cool the earth in micro-forests

When you think of a forest, you probably think of trees. Whilst trees are essential to a forest, other plants layers are important too. These layers include shrubs, climbers and groundcovers.

If you look closely at a forest, you will notice plants jumbled together. These plants are randomly spaced and compete for light, nutrients and water. And plants are a range of different heights, some have just germinated, some have died and some are in their prime.

Tiny forests popping up in Canberra

The Climate Factory works with community leaders to build climate cooling micro or tiny forests. Over 2020-2021 we built the Downer and Watson Micro-forests and in May 2022 construction starts on the Holt Micro-forest. Since 2020 we have been trialling a range of native groundcovers in our forests.

Groundcovers a living mulch in the tiny forest

At the forest bottom are the groundcovers. They have a special role to play. They cool the ground and provide habitat for beetles, skinks and lizards. Eventually the forest will become too shady for some of them and leaf litter may take their place.

Below are three groundcovers we trialled at the Downer and Watson micro-forests.

Hardy Hardenbergia

Hardenbergia violacea (also known as False sarsparilla) is an understorey plant of native forests and woodlands. It grows as a groundcover or twines through shrubs. We like to plant Hardenbergia in the same hole as a wattle to mimic nature.

This hardy plant is in the pea family and bears purple flowers. You will often see it flowering at the same time as wattle. This signals spring is on its way.

Purple flowering Hardenbergia growing amongst wattle.

False sarsparilla has leathery dark green leaves and once established is drought and frost hardy.

ACT for Bees says, its flowers provide food for butterflies, European Honey bees and native Leaf-cutter bees.

This groundcover can be grown from pre-treated seed. To pre-treat seeds, soak overnight in hot water. This should break the seed dormancy. Then plant the seeds in a mix of 50:50 coarse river sand to native potting mix. Depending on conditions, seed should germinate within 10 days to three weeks.

Marvellous Myoporum

This is a fast growing groundcover that comes in two forms. Plants can have either a fine leaf or broader leaf. Myoporum parvifolium is also known as Creeping boobialla. The plant bears small white or pink flowers and creates a living mulch over the ground. It prefers full sun to part shade.

At the Watson Micro-forest we planted it at the forest edges and in pollinator patches. This is so it gets enough sun to grow happily.

Myoporum parvifolium is easy to grow from cuttings. It prefers full sun to part shade.

Creeping boobialla can be grown readily from cuttings.

Tasty Tetragonia

This sprawling groundcover, Tetragonia tetragonoides is also known as Warrigal greens. It is has edible leaves. Captain Cook is rumoured to have used its leaves to stop his crew getting scurvy. 

silver saltbush on the left contrasts with Warrigal greens
Warrigal greens on the right combined with the silvery Saltbush (Rhagodia spinescens) in the Edible Micro-forest, Lonsdale St, Braddon. Prefers full sun to part shade.

It’s leaves are high in oxalic acid and should be blanched prior to eating. In Canberra, its best grown in a sheltered position with adequate water. Warrigal Greens were planted as a groundcover in the Edible Micro-forest display in Braddon.

Warrigal greens can be grown from seed or by cuttings.

In Canberra and other cool climate areas it’s best treated as an annual. Hopefully it will set enough seed in the micro-forests so it self propagates.

Home propagation

In our home propagation area we are trialling some hardy shade tolerant groundcovers for future micro-forests. These include: Ajuga australis, Hydrocytle laxiflora (gloriously known as Stinking pennwort) and Acaena novae-zelandiae (Bidgee widgee).

Hydrocotyle laxiflora or Stinking pennywort is useful for moist shady sites. According to ‘Australian Plants for Canberra region gardens and other cool climate areas’ it can be invasive in garden beds. It grows readily across the soil, rooting at nodes. Greenish globular flowers with a strong odour are held on upright stems. This plant isn’t commonly grown by nurseries, maybe due to its invasive nature and smelliness.

At the Holt Micro-forest we will plant Stinking pennwort and Bidgee widgee. We will also plant Dichondra repens (Kidney weed) which likes shade and moist soils and Viola hederaceae (Native violet) at the dry creek bed edges.

If you’d like to start a community micro-forest or build a micro-forest at home we’ve created videos on these topics.

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

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.

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

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.

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!

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.

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.

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.

The value of a micro-forest

How much does it cost to build a tiny or micro-forest?

Simple analysis

From a simple accounting point of view, the answer is around $500 per square metre. This figure is based on a $40,000 budget and an area of 800 square metres for the Downer pilot project.

At one online-workshop I ran on the Eight Steps to Make a community micro-forest a participant (I suspect an economist or accountant) commented that it was a very expensive exercise. They used simple maths dividing the total cost by the number of trees (1800). Using this method it costs $22 per tree. But this is too simplistic. It ignores the time and expertise involved in engaging the services of green professionals like landscape architects, water harvesters and community facilitators. It ignores that we are creating spaces within the planting that people can use. It ignores the fact that we are creating a much nicer space that can be used by anyone for free.

Modest garden for a family of 5

In 2021, I’d designed a modest garden for a family of five in Canberra on a 1200m2 block. The house and driveway probably took up 500m2. The garden design included water harvesting and lots of planting, a bit like our micro-forests. The total cost to build was $80,000. It made me realise the public micro-forests we are building represent remarkable value.

Micro-forests empower communities to tackle climate change

The Climate Factory’s micro-forest model draws community together with a sense of purpose. Further it empowers communities to make change at a neighbourhood scale. As it grows, the micro-forest will store carbon, reduce park temperatures and provide habitat.

Shown below are the physical assets and the community assets. Typically community assets are harder to measure with numbers.

Physical assets

The physical assets are easy to measure and can be given a dollar figure. At the Downer Micro-forest over 2020-2021 we built:

  • 20 lineal metres of water harvesting trenches
  • 6 square metres of bog
  • 450m2 of shrub beds with enhanced soil
  • 1800 native plants
  • a recycled timber bench
The Cole St, Downer park in 2019 prior to building the community micro-forest was weedy and dry.

Community assets

The project has activated the local community. They now take pride in their local park. This has resulted in the:

  • Creation of the Downer Parkcare Group
  • 1 community consultation to give residents a say about changes to their park
  • 1 informal on-site consultation
  • 4 community working bees (all held during Covid19)
  • Additional working bees led by the Downer Parkcare group.

Community connectedness

Just looking at the cost per square metre of a tiny forest is too simple. This method ignores community wellbeing and connectedness. This is because wellbeing and connectedness are harder to measure in dollars and are often ignored.

However, the leader of the Downer Parkcare Group, Amit Barkay provides a sense of how his community wellbeing has improved.

I like the fact that it brought the community together more than I envisaged, everyone coming to help, kids, young and old. And the fact that the place has changed in a matter of six months. To the point, that two weeks ago there was a couple who just came with a picnic table and glasses and a bottle of wine, to cuddle on the bench just over there. It was absolutely lovely.

Amit Barkay, Downer.
Amit Barkay, volunteer leader of the Downer Parkcare group.

His neighbour, Leah Moore describes how the creation of a micro forest or tiny forest has enhanced the Downer community. She talks about the physical and community changes that occurred. Leah says,

… there’s been a miraculous transformation. This park used to be quite bare of trees in the middle part here and through the drought got very dry and now we’ve got this flourish of growth and it’s very very green and our communities got behind it. So we’re all in this together. I like that too. I like interacting with my neighbours like that.

Leah Moore, Downer.
Mother and daughter at a planting bee at the Downer tiny forest
The community planted the entire Downer tiny forest during COVID 19.

A model for the future

This project demonstrates a new way of regreening public spaces. Rather than competing for scarce grant money, projects like the Downer and Watson Micro-forest are funded via crowdfunding.

Maintenance expenses

All public landscape projects will require some maintenance in the future. Under The Climate Factory model the community commit to maintain the tiny forest for its first two years. The main job is hand weeding and disposal of weeds.

The micro-forest also saves local authorities on mowing costs. By turning grass into garden beds at the Downer Micro-forest, there is 450m2 less grass to mow.

Eight steps to build a community tiny forest

The Climate Factory has built two community micro forests in the ACT with a third to be constructed in 2022. And the vision is to create a micro forest in every urban hotspot in Australia.

Founder of The Climate Factory, Edwina Robinson says she created the eight step method to show others how to create a tiny forest. In fact, the method can be applied to almost any community revegetation project. She says,

The 8 step method can be applied to any community regreening project. You could use this method to create a food forest or a pollinator garden, it doesn’t have to be a micro-forest – the principles and the stages are the same.

EDWINA ROBINSON, FOUNDER, THE CLIMATE FACTORY

The Climate Factory has created a 54 minute video on the Eight Steps to make a climate-cooling micro-forest.


Climate ready trees in tiny forests

2019 was Australia’s hottest and driest year on record.

Studies show trees significantly reduce temperatures. So by planting more trees in our cities and towns we can adapt to climate change.

Urban areas get hot

Urban areas are typically hotter than the countryside. That’s because when we build cities we remove trees and pave over waterways. And the building materials we use, like concrete and asphalt, absorb heat and release it slowly at night.

A study by the CSIRO found in summer Canberra’s urban areas were up to eight degrees hotter than surrounding rural areas.

Tiny forests battle climate change

In 2020, The Climate Factory built its first tiny forest or micro-forest in Downer in the Australian Capital Territory. This weeny forest occupies just 450m2 of suburban parkland.

The tiny forest is modelled on the Miyawaki method. The Miyawaki method plants native plants densely which leads to fast growth. The layers of native plants improve local biodiversity.

Young leaves of a Kurrajong in the Downer tiny forest in Canberra.

However, Edwina Robinson founder of The Climate Factory, realised she needed to take a different approach to climate change. Robinson decided not to use local native trees in the tiny forest. Instead she experimented with growing trees from hotter and drier climates. Plus she integrated simple water harvesting methods to direct water deep into the soil.

Australian National University tree study

In 2019, the Australian National University released a study showing the trees most likely to survive a hotter, drier Canberra. Top of that list was the Kurrajong, Brachyciton populneus.

The signature tree of Canberra’s tiny forests

In 2020, Robinson worked with local community to build a second micro-forest – the Watson Micro-forest. The Kurrajong has become the signature tree in both the Downer and Watson tiny forests.

These Kurrajongs are planted at
the Banksia St, O’Connor wetland and are around 10 years old.

The Kurrajong is a sturdy evergreen Australian native tree with green glossy foliage. It grows slowly and may only reach four metres high in 10 years. Although this tree grows naturally in the Canberra region, The Climate Factory sourced plants from a nursery six hours north of Canberra. This nursery experiences temperature extremes of 49°C in summer and -9°C in winter. So these trees are likely to thrive in hot and dry urban environments.

As well as planting Kurrajongs, a number of other native trees are being trialled. The list includes the Queensland Bottle Tree, She-Oak, Allocasuarina and Silky Oak.

Ngunnawal use of the Kurrajong

The Ngunnawal people have lived in the Canberra region for tens of thousands of years. They used the bark of the Kurrajong to make string and rope. Kurrajongs have hard dark brown seed pods. The pods were turned into children’s toys. And inside the pods are seeds which are edible when roasted over a fire.

Does planting densely cool the landscape?

Robinson says she ordered temperature and humidity loggers to install into the micro-forests in 2022. Data from the loggers will be retrieved with smart phones. She will test if the dense planting of a micro-forest cools local temperatures.

To compare different planting approaches, one logger will be placed within the micro-forest and another one in a mature park tree with grass underneath. Time will tell if the dense planting cools the landscape. Robinson, says the inclusion of water harvesting should help keep temperatures down.

Resources

How to build climate-cooling micro-forest in 8 steps – video