1044 Beaudesert Beenleigh Rd – Restoration Project

The following document describes project methodology and on-ground works implemented during site rehabilitation. This includes industry ‘best practice’ techniques with consideration to obtaining the most ideal environmental outcomes. Further recommendations ensure future success of this weed management project.

The property owner Steve Orchard contacted Forest Rehabilitation Ecology with view to conduct a site visit for vegetation assessment and future assistance with site rehabilitation. This was carried out on the 20^th March 2018. The initial works commenced on the 27^th of March 2018. 

Site History

This property is 68 acres and consists of a sub-regional wildlife corridor between coastal reserves in the Gold-Coast region and Mount Tamborine.

Approximately 10% is remnant Lowland Rainforest on Floodplain which is listed as an endangered ecological community under the Threatened Species Conservation Act 1995.

The previous landowners have installed aquaculture ponds and infrastructure to support a commercial operation. They have also installed hundreds of tyres into the ponds and surrounding riverbank.

During the site inspection some significant species of interest were noted on site such as a stand of mature Forest Red Gum (Eucalyptus tereticornis) and dominant population of Black Bean (Castanospermum australe), Whalebone Tree (Streblus brunonianus), Pepperberry (Cryptocarya obovata), Three veined Laurel (Cryptocarya triplinervis), Native Frangipani (Hymenosporum flavum) and Rough Leaved Elm (Aphananthe philippinensis) in the rainforest remnant. She Oak (Casuarina cunninghamiana), Weeping Bottlebrush (Melaleuca viminalis), Creek Sandpaper Fig (Ficus coronata) and Black Melaleuca (Melaleuca bracteata) dominate the immediate riverbank zone.

Site Location Map

Soils and Hydrology

The dominant soil type is sandy loam along the riparian system. Alluvial flood plain silty and sandy loams are confined to the foothills and lowland areas. These soils are highly fertile due to replenishment of silts and sediments from Albert River flood events. The soils on the steep riverbank areas are quite unstable with a high sand content so exotic grasses have been retained in these areas to ensure bank stability and flood resilience.

The property has several small catchment lines and creek-line gullies as a significant flow of water occurs during rain events along the steep slopes of the to the lowland floodplain.

Weed Species List – Prior to Weed Control Works

Restoration Techniques

Treatment Methodology

Cut, Scrape and Paint

A knife is used to cut and disconnect vine weeds (such as White Glycine) near the root system and gently scrape the stem and apply systemic herbicide directly to the cambium layer and vascular tissue of the plant to ensure optimum chemical uptake of difficult to kill weeds. Untreated vine cables with vegetative reproductive capacity are rolled up and hung in trees to prevent contact with ground moisture.

Cut, split and paint

The stem is cut within 20-40mm from the ground and a knife is used to split the stem vertically 2-4 times to open-up access to the vascular tissue for chemical absorption. This method of treatment is very effective in controlling fleshy watery weeds that can dilute the applied chemicals. This method is highly effective with treating mickey Mouse Plant.

Cut Stump

This method involves the felling of the entire plant with the remaining root stock and stump treated with herbicide. The plant is felled at ground level to avoid potential trip or puncture wound hazards to individuals moving within the site. A concentrated herbicide solution is applied immediately to the exposed surface at a ratio of generally 1:1 with water. The remainder of the plant should then die if treatment has been effective. Stumps are left in place to reduce erosion and maintain soil structure and stability.

Scrape and Paint

A knife is used to gently scrape the stem and apply systemic herbicide directly to the cambium layer and vascular tissue of the plant to ensure optimum chemical uptake of difficult to kill weeds.

Spray Preparation

Prior to spraying all the areas will be checked for any native seedlings and flagging or buffers will be created using manual removal to prevent any off-target damage. The landowner has agreed to assist in manually removing the Arrowhead Vine where it is impacting trees with Staghorns to assist in more time efficient treatment follow up for the team of technicians.

Foliar Spray

A knapsack spray unit is used to apply a water diluted herbicide and dye mixture over all the foliage of a plant. It is essential that as much of the foliage is covered as possible to ensure an effective treatment. This method kills the invasive species and results in a stem frame left ‘in situ’. The standing remains of these weeds provide shelter for establishing native species by reducing the effects of adverse weather conditions and preventing physical damage by reducing access to the area.

Manual Removal

The plant is grasped firmly at the base close to the soil surface and gently but firmly pulled from the soil ensuring that tap roots or tubers are removed to reduce the potential for regrowth. Herbaceous weeds and grasses are most effectively treated using this method. Once the weed is removed it is left exposed on the soil where it dies. No vegetative reproducing species are treated in this manner. If one of the plants is removed with viable seed it is placed in a heavy-duty bag and disposed of through council landfill.

This method is employed when working in close proximity with native species, and when chemical treatments are unacceptable due to the risk of spray drift. The hand removal method allows for the selective clearing of weeds within rehabilitation plantings and natural rehabilitation areas. This treatment is often employed during rain when chemical treatments are ineffective.

Stem Injection

A cordless drill is used to create a 45˚ angle hole in the trunk of the target weed and this is repeated horizontally in a circular motion around the trunk – preferably around the base or where a complete ring can be installed. Each hole is to be filled with herbicide within 20 seconds of completing each hole to ensure immediate chemical uptake. Holes are to be spaced 100mm apart.

Splatter Gun

This technique requires a grid pattern of chemical applied every square metre at a rate of 1:9. Extra care is taken to prepare the site for this application technique to ensure no off-target damage. It is highly effective in treating various weed infestations such as Lantana. The benefit of this method is the grid pattern enables some retention of native vegetation such as grasses/herbs during treatment so the area has a much faster re-establishment of native cover. 

Equipment Utilised for Regeneration Works

• Loppers
• Knives
• Secateurs
• 12L Spray Pack
• Cordless drill + bits
• Applicator bottles
• Bags for weed seed removal
• Chainsaw
• Hedge Trimmer

Site Weed Incursions

Recommendations

The following recommendations provide a guide for on-going ‘best practice’ treatment techniques that will be utilised throughout the duration of rehabilitation works. These recommendations have been developed to control impacts specific to the site and to provide a minimal disturbance approach to controlling weeds with view to controlling weeds and utilising slashing, hand weeding and other more organic techniques after initial progress has been made.

A significant weed density on the property has been noted and this needs to be managed sensibly to ensure areas of intact native vegetation are worked comprehensively and remain treated and clear of weeds as we progress through the site. This will enable natural regeneration and the seed dispersal or native regeneration through birds and the surrounding reference community which includes Wickham Timber Reserve and Plunkett Conservation Park. In addition, areas cannot be opened-up too quickly as the added light will encourage further weed germination and there is a concentration of weed germination through most forest areas. Weed retention for structure in some areas will ensure bank stability prior to follow up revegetation works to required to allow a progressive recovery of the site. 

Summary

The selected methods for site rehabilitation ensure a gradual change to the site for the least disturbance to local wildlife and responsible chemical application. The plan to utilise the structure of the woody weeds such as Camphor Laurel and Mulberry will assist in creating initial protection and microclimate for native seedling recruitment through the heavy weed incursion areas. This will also minimise potential for erosion.

Succession of weeds: The restoration plan included following ‘best practice’ rehabilitation techniques, starting with canopy vine weeds, followed by woody ground weeds and groundcover weeds. Stem injection of tree and large shrub weeds will be carried out strategically to prevent overhead hazards whilst primary work is carried out and erosion potential.

A total of 10600 m² primary work has been completed in conjunction with follow up works of 5600 m² to manage the subsequent weed germination after initial treatment was carried out. Large densities of treated weeds have been billeted up and mulched into the site to help create a mulch layer and ease of access for follow-up works.

Photo-points have been installed for site reporting and to show evidence of the transition from heavy weed incursions through assisted regeneration to enhanced native cover.

At the landowners request we created a highly effective chemical treatment plan which is least likely to be residual and easily broken down within the soil to provide the least amount of disturbance to the site as possible.

References

Chenoweth EPLA and Bushland Restoration Services (2012) South East Queensland Ecological Restoration Framework: Code of Practice. Prepared on behalf of SEQ Catchments and South East Queensland Local Governments, Brisbane