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Ambers Gully and Free A Tree update

Liz Milner | Published on 6/27/2021

For those of you who don't know the Ambers Gully project site, it is a beautiful grassy woodlands site at the northern end of Black Hill Conservation park protecting stands of South Australian blue gum, river red gum and black mallee box (Eucalyptus leucoxylon, Eucalyptus camladulensis and Eucalyptus porosa).

For many years the focus of this project has been removing Erica (Erica arborea) from the site. In 2016, 13.4 ha of native grassland was being smothered by this introduced plant. We have reduced the area of primary infestation down to just 5.2ha, and cleared the the other 8.2 ha of all woody weeds. However, as with all works we perform the devil is in the detail and we are now seeing a return of many small Erica seedlings.

Over the past 12 months, Friends volunteers, with the help of the 4WD Adventurers club members who are also driving us up to the project area, have moved from clearing the initial infestation to hand removing these seedlings. Mid 2020 a trial was performed by contractors and departmental staff to determine how best to treat these emerging plants. The trial has successfully identified a reduced chemical rate which affects these seedlings without adversely affecting established natives. Last month the area first cleared of Erica in 2016 was sprayed using this method. It is too early to know how successful this has been but we are hopeful of a good outcome!

In the meantime volunteers will be out continuing the hand removal of these seedlings and giving our native species the best possible chance of regeneration. You can register to come along to the August event online!

Upcoming Events

Emerging Erica seedlings

Our Free a Tree fund-raising campaign continues to be of paramount importance in the Black Hill Conservation park. Those of you following the project will know about the devastating effect olives surrounding the base of the trees have had. Last year all the largest significant trees within the Ambers Gully site had the olives around them treated. Mid 2020 we visited the project with the parks ecologist Anthony Abley to determine what would be the best focus moving forwards. Anthony's view was that with the very real and imminent possibility of losing significant trees on the Sugar Loaves side of the gully we should move our focus there.

This image clearly shows the before and after affects of the contractor works in the Ambers Gully site. Before the olive treatment there was the very real possibility of losing this tree. Now that the olives around the base have been treated you can see the tree recovering by growing new shoots from epicormic buds that lie dormant beneath the bark. This growth is normally suppressed by hormones from active shoots higher up the tree, but when there is trauma from factors like insect attack, drought or fire, or in our case olives, these buds are activated. It makes you realise just how stressed these trees were. It will take a few more years for the full canopy to start to reform.

This year all donations have been put towards performing similar works through the Sugar loaves (south) side of the Ambers Gully Track. Contractors have completed the autumn works and we are just seeing the olives beginning to yellow now. Yes, it is a slow process! We have focused on the largest trees in the gully and along the top of the Sugar Loaves Track with the view of working top down through the site. Being the southern slope it receives more sun than the other side and we are finding there are quite a few trees which we have already lost in this area.

This image shows a very large significant tree below the Sugar Loaves Track, with all of the olives dead around its base - yes, that trunk is many metres around. It is actually quite difficult to photograph the work which is being performed on the ground for this project as the trees are so large! It is also hard to distinguish the recovering canopy from trees in the foreground, but the image clearly shows the large number of dead olives around the base.

This tree is continuing to recover well. We are concerned about the long-term need to follow up on these works as new olive seedlings will have to be tackled before they become a problem. The Free A Tree campaign will be with us for a few years yet!

Our thanks to everyone who has supported this project.

Friends members and 4WD Adventurers working together
We really appreciate all the donations Friends members and many members of the general public have put towards saving these majestic trees. Our fund-raising for this project is ongoing and all donations are tax deductible within Australia.

Donate to this project here

Volunteer Opportunities!

1. Are you keen on taking ownership of your own project? Are you passionate about restoring this area of the park? We are currently looking for a project co-ordinator for this project.
2. Do you have an interest in helping us fundraise for this and other projects?

Contact us for more details about making a real difference on the ground.

Contact Us

This project is currently being supported by funding from the Green Adelaide Grassroots Grants 2020/21.