Last Saturday we held a working bee, weeding at a site (which we do annually) where an invasion of Sycamore Maple seedlings entered the Park from a surrounding property. Initially we were pulling out hundreds of new seedling and now the ongoing effort to remove newly detected seedlings is working well. Like last year there was not a lot of Maple to remove and a lot of the time was spent moving through the site to ensure that the area was clean of weeds, (although we did not get cross to the other side of the gully where there are some more Maples growing). The main area where Maple was found was an open disturbed area that also has a very bad Tutsan infestation.
It was interesting to discover that much of the Tustsan in the area was covered by rust with some foliage looking quite heavily impacted. We didn’t notice the rust last year but when I looked back at some photos I took then, I did see that some Tutsan leaves had tell tale rust spots present. Tutsan Rust (Melampsora hypericorum) is a fungus that was found to be very successful in the Otway Ranges in the 1990’s where it had a significant impact on reducing the cover of this shade tolerant invasive weed.
Our site (or somewhere in a close vicinity) had Tutsan Rust artificially introduced a couple of years back and after some follow up inspections It was thought that it had not taken. After a bit of research I found a document that suggested that Tutsan Rust was already present at Tarra Bulga, A report from 1999 describes rust taken from Tarra Bulga (as well as some from the Morwell River area) being used as part of research project. The Tarra Bulga rust was found to impact the plants in the trial to an intermediate level (i.e. OK but not great). Whether or not the rust is from the attempted introduction a couple of years ago (of which I assume was a more virulent strain) or whether it is the same rust that has been around for longer, can probably not be known without complex Laboratory analysis. But we will continue to monitor the site with interest given the threat that Tutsan presents to the park.
As well as the Maple and Tutsan there were new Blackberry seedlings that we carefully hand pulled as well as a few new outbreaks of English Ivy which we need to remain vigilant for. There were some larger clumps of Blackberry that will need to be sprayed.
When cyclists from the Great Victorian Bike Ride “ascend” on Tarra Bulga next week they will notice along with the many native plants in flower some attractive looking flowering plants that are in fact not so desirable. One of the most obvious they will see is Creeping Buttercup – (Ranunculus repens). Although there are native Buttercup species this one comes from the Northern hemisphere. As can be seen by the sea of yellow along the roadsides at this time of the year, it has been well established for a long time and has also penetrate to some moist areas deeper in the park resulting in the displacement of native species.
Another weed that is threatening to take over and become more of a pest is Myosotis sylvatica or Wood forget-me-not. There are also native relatives of this plant in existence, but this species is native to Europe and has been introduced to Tarra Bulga from garden escapes. It is popping up all over the roadsides and is threatening to penetrate deeper into the park. Park staff and volunteers are vigilant in trying to remove seedlings whenever they are encountered but the task seems to be getting more difficult.
On Saturday March the 31st the friends held their annual Sycamore Maple pull. It was very encouraging to see that although there were still quite a number of large seedlings (up to 2.5m tall) and a bit of re-sprouting from previous weeding efforts. There was only a handful of new seedling sprouting (despite the wet seasons we have had) compared to the hundreds that we were pulling out when we first started working on this site back in 2006.
The source of the infestation was from some large established trees planted on the other side of the Tarra Valley Road. The large trees for many years had blown their light papery seeds into the surrounding native forest. Thanks to our efforts in starting the work in the park and with co-operation with the WGCMA and Parks Victoria, work was done to remove these large established trees, The photo above shows a large tree maple that was ringbarked and poisoned. Now all that should be required to stop the maple from spreading into the the magnificent forests of Tarra Bulga is a quick bit of regular follow up to eliminate any seedlings that pop up from viable seed still stored in the soil or regrowth of plants that we have already pulled out.
Sycamore Maple Removal
Fortunately we did not find to many plants that had re-grown but it was apparent that the ones that did resprout were generally not cut off very close to the ground. So the lesson learnt “cutting the stems as close to the ground as possible is vital”.
While we have had some great success with the maples here we have some more significant tasks ahead. This includes efforts to re-habilitate the site (only recently discovered) of a huge infestation of around 2ha of established maples in the park. In this area of the park there are also large infestations of Tutsan and Blackberries that are of great concern.