Imbil State Forest - A plan to to bring back endangered lowland rainforest

Black-breasted Buttonquail

The Queensland Government is considering an unusual proposal to stop logging pine plantations and grazing in a Sunshine Coast hinterland state forest to create a major reserve of a critically endangered habitat. Recent media coverage of the plan can be found here.

If the plan is implemented, it would be the first time in Australia that extensive areas of plantation were allowed to revert to native forest. The 21,000-hectare Imbil State Forest would become the first substantial area of subtropical lowland rainforest habitat to be protected.

Subtropical lowland rainforest once covered large areas of south-east Queensland and north-east NSW. In one of Australia's great environmental missteps, most was cleared in the nineteenth century for agricultural development. More recently, especially in Queensland, large areas were bulldozed for pine plantations, particularly native Hoop Pine Araucaria cunninghamii.

Today, just a tiny fraction of the original area of lowland rainforest survives. The forest once extended south from Maryborough in Queensland to Grafton in New South Wales. Subtropical lowland rainforest was listed federally as a critically endangered habitat in 2011.

With the forest has gone the many plants and animals that called it home. Most notable is the Coxen's Fig-Parrot, which once occurred across the region but has not been recorded with certainty since the 1980s. It was found nowhere but in the lowland rainforests of south-east Queensland and north-east NSW. The Black-breasted Buttonquail, listed nationally as Vulnerable, is similarly restricted to remnant lowland scrubs of the region. So too is the impressive Giant Barred Frog.

Many other rainforest animals, such as several species of fruit-eating pigeons and some frogs, are much more numerous in the surviving lowland rainforest remnants than in the better protected highland rainforests that are found in areas such as Lamington and Bunya Mountains national parks. The wildlife of lowland rainforest is struggling to survive in remnant forest patches. Land care groups battle to keep the forest patches free from invasive vines and other introduced weeds.

Original extent of subtropical lowland rainforest

Lowland rainforest typically includes a greater variety of trees, vines, ferns and other native vegetation than highland rainforest, and many plant species are restricted to it. Over the region in which it occurs, the forest has the most diverse tree flora of any vegetation type. Subtropical lowland rainforest is today found only in small, isolated patches. There are no substantial reserves of the habitat. It's not too late for that to change, however.

The foothills of the Conondale and adjoining mountain ranges in the Sunshine Coast hinterland were once clothed in lowland rainforest, the drier kinds of which are often referred to as vine scrub. The remnant scrub to be found in this region today contains the largest surviving populations of Black-breasted Buttonquail and good numbers of many other lowland rainforest animals and plants that have disappeared from elsewhere. 

Lowland rainforest remnant, Imbil State Forest

Most of the lowland rainforest in the region has been converted to Hoop Pine plantations which are extensively interspersed with remnant forest patches. Hoop Pine is one of the dominant native trees in subtropical lowland rainforest. When stands of Hoop Pine plantation are left unlogged, they are colonised by native vines, palms and other plants from adjoining remnant habitat. Wildlife such as birds of the forest understory and many mammals and reptiles will happily inhabit the plantations. Eventually, if left alone, the plantations will regenerate as subtropical lowland rainforest.

About half the native vegetation of Imbil State Forest has been converted to Hoop Pine plantation. The remainder is a mosaic of open forest and what are likely the largest tracts of surviving subtropical lowland rainforest. Fortuitously, reasonable numbers of tall trees with hollow logs, needed by animals such as possums and parrots, survive in the remnant forest. The rainforest patches include many large fig trees, a major food source for many birds. Despite consisting substantially of pine plantation, Imbil State Forest is an excellent site to find rare or cryptic wildlife such as the Platypus, Black-striped Wallaby, Masked Owl and Black-breasted Buttonquail.

In a proposal submitted this week, the Queensland Government is being asked to stop the harvesting of plantation timber over the whole of Imbil State Forest and declaring the state forest a conservation park. Under this plan, the clearing of further remnant native vegetation would stop and pine plantations would be left alone to be allowed to regenerate as subtropical lowland rainforest; they would resemble the original forest more quickly than might be appreciated.

Queensland botanist Michael Olsen has no doubt the plantations, if left alone, would readily revert to rainforest. He says: “The Hoop Pine plantations have increasing biodiversity with age, particularly with native plant species, after being planted or logged. This is most apparent where they are located on former rainforest sites embedded in, or contiguous to, remnant rainforest. This is the case with the majority of the plantations in Imbil State Forest…. The protection of such a depleted biodiverse community should be a priority from any perspective.” 

Recently planted hoop pine with rainforest and eucalypt forest in background, Imbil State Forest

Respected landscape ecologist Peter Stanton, the Australian Wildlife Conservancy's land management officer, is using Hoop Pine as the primary tree to rehabilitate 27 hectares of rainforest on the Atherton Tableland. He says if remnant rainforest occurs near plantations, they will regenerate with the help of seed dispersal: “This is a great idea and its aims are quite achievable. If I was trying to rehabilitate rainforest I would always start off with Hoop Pine. With the pines in, it doesn't take much to get the rainforest to come up underneath.”

Imbil State Forest is an important recreational resource. It includes Charlie Moreland, the most popular bush camping area in the Sunshine Coast hinterland. The area around Charlie Moreland, at the southern end of the state forest, is a mosaic of Hoop Pine plantation, lowland rainforest and open forest that is typical of the forest more broadly. It has long been regarded as one of south-east Queensland's primary bird-watching destinations. At the northern end of the state forest, Stirling's Crossing is popular with visitors and is one of the best places in the region to see Platypus. 

Platypus in Imbil State Forest

The Imbil plantations, the first to be established in Queensland in the early-1900s, are logged by HQ Plantations. They comprise a small proportion of the 330,000 hectares of pine plantation managed by the company in Queensland, including in nearby state forests such as Jimna and Amamoor. Losing logging access to less than 5 per cent of the state forests would have little impact commercially, and could be compensated for by the enhanced opportunities for ecotourism offered by a conservation park.

David West, group manager stewardships with HQ Plantations, says that while the company was open to discussion, “we would require more detailed information before we could offer any thoughts on this proposal”. He declines to put a value on the company's Imbil leases or speculate on whether HQ Plantations would be entitled to compensation for the loss of the leases. 

Masked Owl in Imbil State Forest

The area could eventually be added to the adjoining 35,658-hectare Conondale National Park, increasing its size by more than 50 per cent and adding enormously to the park's already impressive biodiversity value. Imbil State Forest is divided by Yabba Creek Road and the creek of the same name. Both portions, the 4,000-hectare Imbil State Forest 2 in the north and the larger Imbil State Forest 1 south of Yabba Creek, are included in the proposal.

The Queensland Government is considering an unrelated submission by the National Parks Association of Queensland to link the Conondale and Wrattens national parks. Called the Yabba National Parks Link proposal, it would add 20,000 hectares to the parks by linking them through the acquisition of remnant native forest areas in several state forests, including the western part of Imbil.

The proposal would help protect 18 threatened wildlife species and 15 ecosystems listed as Endangered or Of Concern. It would not interfere with the harvesting of pine plantations and while worthy, does not include those parts of Imbil State Forest that are particularly rich in wildlife populations.

Under the 1999 South-East Queensland Forestry Agreement, a good deal of state forest in the region would eventually have been made national park, but the agreement was torn up by the former Campbell Newman-led Liberal National Party Government. It has not been restored by the Palaszczuk Labor Government.

Recently logged hoop pine, Imbil State Forest

The Newman Government also introduced widespread grazing leases over state forests, including Imbil, which have not been revoked. Serious damage is being done to remnant rainforest patches in Imbil State Forest by large numbers of cattle which roam freely over much of it. Grazing would be banned if the forest was made a conservation reserve.

The state forest is fortunately free of mining permits, which can be a major impediment to the declaration of new nature reserves in Queensland.

Former Queensland Environment Minister Pat Comben backs the plan to convert Imbil State Forest to a conservation reserve, saying subtropical lowland rainforest urgently needs protection: “As Queensland doubled its national park estate in the early 1990s, we protected areas such as the Mitchell Grass Downs and Mulga Lands. Now the challenge is to ensure the biodiversity of south-east Queensland is similarly protected before it is too late.”

Leading zoologist Glen Ingram describes the destruction of subtropical lowland rainforest as an environmental disaster. He says: “It was a mindless series of mistakes and the impact on our fauna and fauna was devastating. The return of the Imbil forests would be an important step towards rectifying those mistakes.”

Sunshine Coast Environment Council co-ordinator Narelle McCarthy also supports the plan: She says: “With so much already lost, particularly on the coastal lowlands, it is extremely important to retain and enhance what patches remain. Imbil State Forest offers such an opportunity.”

BirdLife Australia Sunshine Coast convenor Ken Cross is enthusiastic about the proposal, He says: “We have lost too much of this habitat already and sadly it may not be good enough in the long term just to protect the area that is still left. We would support this plan to utilise existing native plantations to grow the area of available lowland rainforest and increase the available habitat for many of our endangered bird species.” 

Logging hoop pine, Imbil State Forest

Adding their voices, Protect the Bushland Alliance co-ordinator Sheena Gillman and BirdLife Australia Southern Queensland convenor Judith Hoyle say: “The value of these particular forest areas is not only as significant biodiversity reserves but as ecotourism hot spots within easy reach of Brisbane and the Sunshine Coast. Appropriately managed, they are of financial value to local commerce and rural industry. We support this endeavour to have these forest areas considered for conservation and heritage protection.” 

Charlie Moreland Park, Imbil State Forest

The proposal was submitted last week to Queensland Environment Minister Leeanne Enoch and Agricultural Industry Minister Mark Furner. In time, other areas of Hoop Pine plantation may be allowed to revert to subtropical lowland rainforest.

Ms Enoch says the proposal will be considered by the government: “The Queensland Government is always open to considering suitable state land for its conservation value, including as protected area. The government is currently developing a new Protected Area Strategy, which will help evaluate where lands may be available to grow Queensland’s protected area estate. In relation to Imbil, I understand any proposal to convert all or part of this plantation to protected area status would need the agreement of HQ Plantations.”

See here for more on birds found in the hoop pine plantations.

You may wish to register your support for the proposal to make Imbil State Forest a conservation park by flicking an email to the state ministers. Please note, if the links don't work, copy and paste the email addresses:

Hon Leeanne Enoch,

Minister for Environment,

environment@ministerial.qld.gov.au

Algester@parliament.qld.gov.au

Hon Mark Furner,

Minister for Agricultural Industry,

agriculture@ministerial.qld.gov.au

Ferny.Grove@parliament.qld.gov.au

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Birds in the hoop pine plantations

More images and a response to critics

Imbil State Forest