Trees In The Wrong Place

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No Palm, No Harm

This is the call of wildlife carers along the east coast Australia who are regularly called out to rescue wildlife that has been injured or become entangled after feeding on Cocos Palms.

The Cocos or Queen Palm (Syagrus romanzoffiana) is native to Brazil in South America. Until the late 1990s this resilient, drought tolerant species was one of the most planted palms in Queensland and still features prominently in several historic (state heritage listed) sites including the City Botanic Gardens.

The Cocos Palm has become widely naturalised and can be found growing from Darwin to Hobart. This palm is now regarded as an environmental weed due to its ability to prolifically reproduce, creating thick carpets of seedlings that outcompete recruiting native species. It is commonly sited in urban bushland, riparian areas and dry eucalypt forests.

Like many Councils, Brisbane City Council has actively managed this palm’s weed potential by reducing the number of specimens on site to hold one representative collection only, and undertaking seed removal of these remaining trees.

While it is not a prohibited or restricted invasive plant under the Biosecurity Act 2014, it is a Class “R” under Council’s Brisbane Invasive Species Management Plan. This declaration encourages residents to actively reduce populations of this palm via complete removal.

One of the native animals most affected by the presence of Cocos Palms is the flying fox, often called fruit bat. Flying fox numbers have significantly decreased during the past 50 years; the Spectacled Flying Fox and the Grey-headed Flying Fox are now classified as ‘Vulnerable to Extinction’ on the Federal Government’s Threatened Species list.

Deadly Attraction

Ironically, by feeding on Cocos Palm fruit, flying fox populations are spreading the very seeds that are contributing to the mammal’s rapid decline. Flying foxes have the ability to cross-pollinate over great distances and carry fruit and seeds far away from parent trees. They can fly around 40 kilometres per hour and up to 50 kilometres each night.

Fruits occur in large clusters and consist of a hard nut surrounded with a thin layer of fibrous flesh that is orange and sticky when ripe. The fruit can be toxic for animals and the fibrous seeds can create gut obstruction or become wedged in the animal’s teeth, leading to a slow death by starvation.

Latest information shows that flying foxes are now suffering from the premature wearing of teeth due to availability of the hard seeds all year around.

Wildlife carers warn that the sound of noisy birds around a Cocos Palm could mean there is a flying fox trapped in the massive strappy fronds or it has its wing membranes damaged from the tough flower spikes.

Australia – lucky to have its flying pollinators

Australia is the only continent in which the dominant trees are pollinated largely by birds and mammals (some of which are highly mobile) as well as by insects. Australian plants invest very heavily in pollination compared with trees in Europe and North America, most of which are pollinated by wind.

Author Tim Low, talking about ‘Climate Change Myths’, points out that contrary to popular belief, many Australian plants won’t need to migrate in response to climate change. Fossil and genetic evidence suggests that eucalypts, banksias and many other woodland trees survive climate change in situ by producing genetically variable offspring, some of which prove well adapted to new climatic conditions.

This is made possible by very high investment in pollination, which sometimes occurs between different tree species, resulting in the rapid evolution of new eucalypts by hybridisation. Eucalypts hybridize on a scale unmatched by any other trees on earth.

“This palm is now regarded as an environmental weed due to its ability to prolifically reproduce, creating thick carpets of seedlings that outcompete recruiting native species.”

Flying Foxes:

  • Are very clean animals and constantly groom their fur and wing membrane.
  • Have a complex social system and spend their day in permanent tree-top communal camps.

Have more than 20 different calls for communication

  • Have old males guarding the boundaries of the camp keeping a look out for predators such as eagles and pythons.
  • Lyssavirus is not spread when flying foxes fly overhead or roost in trees; it can only be transmitted through deep tissue bites or scratches.

Gardening Australia television presenter Jerry Colby Williams says “our flying gardeners are a priceless environmental service that sustains our natural environment”. He urges gardeners to help save the species by getting rid of existing Cocos Palms or at least having the flowers cut off before they seed. “Any gardener who grows a Cocos Palm will be aware of how much seed they actually set – seed by the barrow load – and that’s the problem. They germinate wherever they fall.

“If you’re thinking of growing a feather palm, try growing a Bangalow, Foxtail or Norfolk palm instead. That way gardeners rooted to the earth can look after the flying gardeners as well,” he advises.

Top a Cocos

In bushland settings, individual palms can be destroyed by cutting the crown off below the lowest frond; it is not necessary to treat the stump with herbicide as it will not reshoot. In gardens and urban areas it is more visually appealing to remove the palm at ground level instead of leaving a stump.

For more info on Flying Foxes contact Bat Conservation and Rescue QLD – bats.org. au or WIRES Australian. Wildlife Rescue Organisation – http://wires.org.au

References

Low, T 1917, The New Nature: Winners and Losers in Wild Australia, New edition, CSIRO Publishing, Collingwood. Wild About Australia 2018, accessed 1 April 2019, www.wildaboutaustralia.com

August 23, 2019 / by / in , ,
Camphors – The Silent Killers

Camphor Laurels – the silent killers of biodiversity.

It’s been nearly 200 years since the first Camphor Laurel (Cinnamomum camphora) was planted in Australia. Native to Asia, the tree was introduced in the early 1820s and first recorded at the Sydney Botanic Gardens.

When people noticed its rapid growth and attractive light green foliage, it quickly became a popular tree to plant for much needed shade. In 1872, the introduction of Arbor Day saw hundreds of thousands of Camphor laurels being planted in schools, church and courthouse grounds and in council parks and gardens. Many of these long-lived trees still line streets of cities and towns today, some being heritage listed. Little did we know that this evergreen beauty would become the most invasive weed species ever to reach Australian shores.

New visitors to the North Coast Region of NSW would be unaware that the picturesque sea of light green they see spreading along creek lines and over hillsides was once a darker shade. The ‘Big Scrub’ covered 75,000 hectares and was the largest subtropical lowland rainforest in eastern Australia until it was cleared for agriculture in the 1840s. The contraction of dairying and banana farming since the 1960s has resulted in large areas becoming infested with camphor laurel. This region includes one of Australia’s 15 biodiversity hotspots and is considered the most biodiverse area in the state. It supports the greatest number of plant and animal species of any area of NSW, and includes the greatest number of threatened species.

The Camphor laurel has divided communities for many years and there have been heated debates as to whether century old trees should stay or be removed.

Gold Coast botanist and consultant David Jinks, like many others, has strong views about Camphor laurels; his work brings him into contact with them almost on a daily basis. He said the need for shade isn’t so immediate that it should override the lethal threat Camphors are to local biodiversity.

“They are a beautiful tree. Where I lived in suburban Sydney, I spent much of my childhood climbing them and I have no doubt they had a very strong impression and positive influence on my long-term career in and love of all things plants.

“But I’m now very aware of their rapidly increasing threat to our rapidly decreasing local biodiversity. Of all the threatening weeds, they are enemy No.1 – by a long-shot. And they’ve yet to reach their epic peak.

“Camphor Laurels are in almost every local vegetation type from urban to wilderness hinterland. I’m currently working on an 85 hectare hinterland property of mostly good bush. We thought we’d have a hundred or so Camphors to deal with but, 18 months later, we’ve killed nearly 400 seeding trees plus taken out thousands of saplings and seedlings. Of the many weed species on site, the only one at every monitoring plot is Camphor Laurel. I’m sure this could be repeated on every similar adjoining property.”

“The need for shade isn’t so immediate that it should override the lethal threat Camphors are to local biodiversity.”

David said Camphor laurel is, without doubt, a slow-motion silent killer of local biodiversity that most people don’t get to see. This highly invasive tree has a tendency to form single species communities and exclude most other desirable native vegetation.

“The only way to reverse the spread of Camphor Laurel is to kill as many trees as possible, as soon as possible. To be completely effective there must be no more Camphor Laurel seed to spread. Put the effort instead into immediate control.

Kill the Camphor Laurel and replace it with a fast growing shade tree,” David said.

A passionate artist and tutor Matty George with his prized turtle chainsaw carving at Camp Creative, Bellingen, earlier this year. Organisers had to reassure some participants that the Camphor laurel timber being used didn’t come from the controversial Church Street tree that was recently chopped down in the main street. Teddy Reynolds shows off dad Paul’s work of art at the chainsaw carving workshop at Bellingen.

A spokesperson from the NSW Department of Primary Industry said Camphor laurel has never been a priority weed at the state level because it is well established in NSW and is very commonly used as an ornamental tree and council street tree. It is therefore not a prevention target.

Weeds are regulated by NSW local government and any efforts to reduce numbers would have to be done at a local or regional scale. Regional Weed Committees prepare and maintain a priority weed list, which includes state priorities; however, it is up to each Regional Weed Committee to determine what is a regional priority for control programs.

Federal Government Grant for project on deflowering Camphor laurels.

The introduction of the Biosecurity Act 2016, which specifically focuses on the shared liability relating to the containment and control of weeds, has been encouraging for weed committees.

A federally funded project commenced in July 2017 to undertake research to scope a handful of chemicals to de-flower or prevent fruit from developing on Camphor Laurel.

The Weed Society of New South Wales Inc. reported in its newsletter ‘A good weed’ there would be potential to use this technique, if successful, on other species.

How To Kill Camphor Laurel?

Contact your local Weed Advisory Service for correct chemical application before cutting a 20-30cm high strip into the outer bark and moist cambium layer to expose the heartwood (approximately 3-5cm deep) all of the way around the trunk. Return to check for suckers in 3-6 months.

Other uses of Camphor laurels Camphor laurel is being trialled as a potential fuel biomass in a north coast cogeneration project to produce electricity. Proposals are advanced to use woodchip for fuel to generate electricity at the Condong and Broadwater Sugar Mill cogeneration plants. This will involve the harvest of camphor laurel on a significant scale to supply this project.

Camphor laurel can be a valuable resource as a commercial timber and is used for a range of products and furniture and various items that can be turned on a lathe.

May 29, 2019 / by / in