Native Plant Revegetation: “Art and Science”

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Since 2012, Carbon Neutral Charitable Fund has collaborated in the revegetation of over 1100 hectares of uneconomic farmland in the Yarra Yarra Biodiversity Corridor. The carbon offsets produced there have been accredited under the international Gold Standard certification, an Australian first, and have contributed greatly to the biodiversity in the area. In order to achieve these staggering results, CNCF has joined forces with project developer Auscarbon which has developed a very effective and low-cost methodology for large-scale restoration in low rainfall areas. Now, CNCF is tackling another challenge: the restoration of Guildford Meadow on the banks of the Swan River in the Whiteman Park Conservation Area.

“It takes a little bit of art, and a little bit of science,”

says native plant agronomist Geoff Woodall. Geoff has been involved with Auscarbon since 2009. He has worked to improve seed treatment, seeding methodology and weed control. Now he will be applying these broad acre techniques to the small-scale Guildford Meadow project.

 

The Process

It all starts with the collection of the seeds. Using only local native plants, the seeds vary greatly in size. “Some are as big as marbles. Others are finer than ground pepper,” says Geoff. 

“Not every year is a good year for seed collection. It’s either feast or famine. So we collect as much as we can and keep the seeds in storage for a number of years until we need them.”

Then follows the preparation of the seeds to ensure their rapid and uniform germination. In order to break the inherent dormancy of the endemic native seeds, they are either boiled or smoked. “This happens in a big smoking room” explains Geoff “we create smoke from burning leaves and other materials. For big scale projects like Yarra Yarra, this preparation process alone can take up to several days. You must realise we’re dealing with millions of seeds here.”

Some species, mostly Eucalypt and some Melaleuca, are not suitable for direct seeding. Those seeds are germinated in accredited nurseries for up to six months until they are ready to be hand-planted in the winter months.

Next is the preparation of the soil for seeding. “The soil is scalped and ripped and the seeds are put in with a machine. This is obviously more cost-effective than planting by hand,’ says Geoff. “Our success depends on putting together an ideal package of different seeds that are best suited to the soil conditions.” On average, about 600 grams of seeds are needed to cover 1 hectare.

What sets our approach to revegetation apart is our exclusive use of local native systems. “Other revegetation projects are monocultures, mainly mallee based,’ explains Geoff. “You don’t find as much diversity in the plants there, and ultimately in the other species that are attracted by it.”

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In addition to the different soil conditions, the wetter Guildford Meadow is presenting a couple of extra challenges, totally different from semi-arid the Yarra Yarra Biodiversity project. As Geoff explains: “We’re dealing with an urban environment here, including multi-use areas: people walking their dogs for example. So you need to plant for that: to allow good access through the planting. Guildford Meadow will be a nice natural addition to the area and an essential part in protecting the river system. It will provide a buffer that will take nutrients out of the water before it hits the river. The local Melaleuca and Eucalypt we’ll be planting there are very good at that.” In addition, the project will also be an important carbon sink.

On average, each hectare planted will remove an estimated 450 tonnes of carbon over a 25-year period, supporting CNCF in its main purpose: reduce our carbon footprint, restore the landscape and conserve natural biodiversity.

 

Related Topics

The direct seeding story of Moresby Ranges