Section 3. Case studies - Weeds Australia
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Section 3. Case studies - Weeds Australia

Case studiesThis section of the Athel Pine National BestPractice Management Manual showcasessuccessful programs against athel pine, tamariskand smallflower tamarisk from around Australiaand overseas.The case studies given feature a number ofcommon key points which have contributedto successful weed control. These points are:• Three Tamarix species in Australia arepotentially invasive across a range ofenvironments and states. Correct identificationof Tamarix species contributes to effectiveplanning and control programs• Popular herbicides with glyphosate as theiractive ingredient are generally not effectiveagainst athel pine, tamarisk and smallflowertamarisk. More specialised herbicides arerequired to kill these weeds. Land managersneed to pay close attention to correctapplication methods and conditions in orderto achieve satisfactory kill rates• When controlling athel pine, tamarisk andsmallflower tamarisk by mechanical clearing,removal of roots as well as top growth isessential to achieve satisfactory kill rates.Removing the roots of these plants will reduceregrowth following clearing• Follow-up and monitoring is an essentialcomponent of any control program againstathel pine, tamarisk or smallflower tamarisk.Follow-up and monitoring must be budgetedfor when planning a control program againstthese weeds.36 ATHEL PINE NATIONAL BEST PRACTICE MANAGEMENT MANUAL

Finke River, NTIntegrated techniques against athel pine(Tamarix aphylla)Sandy Leighton and Jonah GouldthorpeAustralia’s worst athel pine infestation has beentreated along 400 km of the Finke River in theNorthern Territory and is now under follow-upcontrol. Future programs will target remainingdownstream infestations on 200 km of the river.The Finke River is an ancient river system thatstarts its journey in the Western MacDonnellRanges, about 150 km west of Alice Springs andmay reach Lake Eyre during extreme floods. Itis a unique system that has significant natural,cultural and economic values as well as being anicon of central Australia.Athel Pine was first planted as a shelter treearound homesteads, communities, stockyardsand bores in the region during the 1940s and1950s. However, it was not until the 1970sand 1980s that the true weed potential ofthis species was recognised, by which time aninfestation had developed along 600 km of theFinke River.This period of sudden and rapid expansioncorresponded to several large summer floods,which are thought to have provided theperfect environment for seed germination andestablishment. The importance of preventingspread when controlling athel pine was alsoillustrated during this period by dumping ofcut trunks and branches in the Finke River atHermannsburg, which were promptly distributedby a major flood, propagating new infestations.From1989 onwards the Northern TerritoryGovernment began to trial various chemical andmechanical control techniques.Following on from these trials, a strategicapproach targeting upstream infestations, usingan integrated mechanical and chemical controlprogram, was initiated in 1994. By 1998, some130 km of the upper Finke River from Glen HelenGorge to the Stuart Highway had been treated.Since then, additional downstream infestationshave been treated along a further 260 km ofriver to Horseshoe Bend homestead, and onFinke River tributaries including Rudall Creek,Ellery Creek, Lilla Creek, Hugh River and KaringaCreek. Works included bulldozing and bladeploughing of extensive infestations on HorseshoeBend Station by the lessees, Peter and LibbyMorphett, who used a bulldozer with a threemetre rear-mounted blade plough to undertakethe work. Peter explained that blade ploughingopened up infestations which were too dense tocontrol by other methods and gave good controlon trees up to 40 cm thick.Larger plants are cut stump treated with Garlonin dieselWill Dobbie3. CASE STUDIES37

The on-going follow-up chemical control ofseedlings and regrowth is overseen by theNorthern Territory Weed Management Branchwithin the Department of Natural Resources,Environment and The Arts.Herbicide choices and rates used reflect years oftrials and experience working out what kills FinkeRiver athel pine most effectively: smaller plantsare foliar sprayed using Starane TM 200 Herbicideat 10 ml/l plus Nufarm Pulse® Penetrant inwater, while larger plants are basal bark or cutstump treated with Garlon TM 600 Herbicide at17ml/l in diesel. Getting a good result with foliarspray has hinged on using good quality waterfree of suspended sediments.In 2004, a thorough survey of the lower reachesof the Finke River was completed from belowHorseshoe Bend to the South Australian border,highlighting further areas that require control.In 2006, an Australian Government Defeatingthe Weed Menace grant was obtained for theProgression of downstream control of Athel Pinealong the Finke River, to treat a severe 20 kminfestation below Horseshoe Bend homestead.Mechanical control works were undertaken onthis infestation from June to August 2007.These works included blade ploughing of largeareas infested with seedlings, and bulldozingand deep ripping of larger trees by contractors.Outlying infestations were treated by NRETAWeed Officers using Starane TM 200 Herbicide at10 ml/l plus Nufarm Pulse® Penetrant in water.This long-term program has resulted from apartnership between the Northern Territoryand Australian Governments and has also seenpartnerships developed with station lessees andAboriginal communities in central Australia, suchas the Indigenous Tjuwanpa Ranger programcoordinated by the Central Land Council, andCDEP participants from Titjikala Community.The Australian Government, Northern TerritoryGovernment and some station lessees haveborne the significant cost of this work, withthe control bill amounting to about $2 millionof external funding and in-kind work at March2008.Many individuals and changing governmentdepartments have been involved in the workover time, and the passing on of knowledgeand monitoring from person to person has beenimportant for maintaining continuity in the athelpine control program.Successful foliar spraying depends on using quality water38 ATHEL PINE NATIONAL BEST PRACTICE MANAGEMENT MANUAL

Large areas of athel pine were bulldozed in 2007Chris Brown, Regional Weeds Officer withNorthern Territory Government, explained thatthe top priority for athel pine control in thefuture would be to monitor treated sites annuallyand follow-up regrowth with herbicides.It makes sense to concentrate limited resourceson keeping previously treated areas free of athelpine before tackling new infestations. Chris alsoflagged new opportunities against athel pine onthe Finke.The Northern Territory Government hopes to trialaerial spraying of an imazapyr herbicide, subjectto appropriate permits, and will also investigatethe biological control potential offered bydieback observed in athel pine along parts of theriver recently.Control of athel pine on the Finke River hasbeen a 20-year project which has achieved majorsuccesses. Monitoring and follow-up will be thekey to safeguarding clean areas into the futureas control efforts move downstream towards theSouth Australian border.3. CASE STUDIES39

Florina Station, SALessons learned on tamarisk(Tamarix ramosissima)Ashley Harvie and Jonah GouldthorpeAshley and Jeanette Harvie, Rural Solutions SAand the South Australian Arid lands NRM Boardhave battled to achieve tamarisk control onFlorina Station, South Australia, but are now ontrack to succeed.Florina Station is a 42,000 ha sheep grazingproperty on the Barrier Highway 150 km west ofBroken Hill. The Harvies, who have leased Florinafor 23 years explained that the tamarisk thereformed an infestation through nearly 2 km ofSnakey Creek.The Harvies first tackled the infestation in 2000using a dozer to push and pile tamarisk, thenburned the debris where possible the followingyear.Regrowth from roots occurred, which was 1to 2 m tall and flowering when Rural SolutionsSA (part of Department of Primary Industriesand Resources South Australia) initiated anannual follow-up program by contractors usingherbicides in 2003. Dow AgroSciences advisedthem to trial Garlon TM 600 Herbicide plus awetting agent in water as a foliar spray, butunfortunately the results were poor.Vigorous 1 to 2 m tall regrowth from the 2003round of control was followed up in 2004, againusing Garlon TM 600 Herbicide both as a foliarspray in water and as a basal bark/cut stumpspray in diesel. Results were disappointing again,possibly due to dry seasonal conditions or thedifficulty in differentiating between seedling andregrowth tamarisk.Further mechanical clearing was undertaken in2005, using a dozer to uproot and pile tamarisktrees within the creek. The piles did not burnconsistently and some of the cleared materialtook root.John PittTamarisk in flower at Florina Station40 ATHEL PINE NATIONAL BEST PRACTICE MANAGEMENT MANUAL

Remains of bulldozed and sprayed regrowth tamariskWith additional funding provided by the SouthAustralian Arid lands NRM Board, a contractorsprayed the regrowth once in March 2007 usingStarane TM 200 Herbicide plus a spraying oil inwater. This was followed up with a second roundof spraying after brownout a few weeks later,which killed any bushes missed the first time.This killed 95% of the tamarisk infestation, andthe board’s Mark O’Connor believes that theyhave “cracked” the secret of treating tamarisk. Afinal round of spraying in March 2008 dealt withany further regrowth.3. CASE STUDIESRegrowth tamarisk at Florina Station prior to follow-up treatment41

Mark O’ConnorSame plants 12 months after foliar spray with Starane TM 200 HerbicideMany lessons have been learned during thework against tamarisk at Florina Station.Herbicide treatments are not always successfuland different application methods, stage ofgrowth and growth conditions all influence theeffectiveness of herbicides against tamarisk.Significantly, growth from some dozed tamariskmaterial showed that cleared debris must beremoved from the flood zone where possible andthat some form of follow-up treatment usingherbicides is essential to achieving eradication.Ashley Harvie estimates that tamarisk control atFlorina Station has cost in excess of $40,000.Ashley contributed time to spraying the weedand accommodated contractors who performedmuch of the herbicide work.In spite of setbacks along the way, Ashley isupbeat about his progress and believes that only20% of the tamarisk remains to be treated: “Thegood thing about it is it’s getting controllablenow. It’s heartening…”, he says. Future workagainst tamarisk on Florina Station will involvemonitoring treated sites for regrowth and foliarspraying annually in spring using Starane TM 200Herbicide (or equivalent) in water.Years of work have resulted in successful controlof tamarisk and the infestation will eventually bebeaten at Florina Station.42 ATHEL PINE NATIONAL BEST PRACTICE MANAGEMENT MANUAL

Lake Boonderoo, WALessons learned on tamarisk(Tamarix ramosissima)Sylvia Clarke and Jonah GouldthorpeLake Boonderoo is an important habitat forbirds and invertebrates as it dries up, becomingincreasingly saline. Tamarisk was discoveredin the Lake’s shoreline in 2005 and its extentconfirmed when station lessee Mark Forresterflew over the Lake and saw that up to 30 kmof its margin was infested with young tamarisktrees. A total of about 250 ha had been coveredby the weed.A significant wetland on the western edge of theNullarbor Plain has been saved from invasion bytamarisk, thanks to alert land managers.Lake Boonderoo is located on Kanandah Station320 km east of Kalgoorlie. The lake lies on theend of an ancient drainage system which flowsafter cyclonic rain events and is one of only twobrackish lakes in the Goldfields-Nullarbor regionof Western Australia.Work began to eradicate the tamarisk in June2006, when staff from Western Australia’sDepartment of Environment and Conservation(DEC), the Rangelands NRM CoordinatingGroup and Mark Forrester undertook cut stumptreatment of about 70 ha of infestation. Theyused chainsaws and brushcutters to cut shrubsdown then sprayed stumps using Access TMHerbicide in diesel at 1:60. At the same timea 10 x 10 m trial plot of basal bark treatmentwas established. Mature tamarisk trees, whichwere a potential seed source for the lake sideinfestation, were also removed from the nearbyKanandah homestead.Cut stump treatment on a further 120 ha ofinfestation was undertaken in October 2006,again using Access/diesel mix. Photopoints andvegetation monitoring plots were establishedat this time to track progress against the weed.3. CASE STUDIESLake Boonderoo is an important habitat in the Goldfields-Nullarbor region of WA43

Another round of treatment including follow-upon previously controlled tamarisk was undertakenby DEC staff from March to April 2007, using cutstump with Access in diesel. Smaller bushes werecut with a brushcutter and larger bushes with achainsaw.The initial treatments used on tamarisk at LakeBoonderoo were not all effective. In particular,the cut stump treatment from October 2006resulted in a lot of regrowth. This is attributed to:• High temperatures at the time of application• Herbicide not applied quickly enough aftercutting to penetrate stumps• Health of trees. However, the kill rate wasbetter during the June work when trees werebrown and senescing, whereas they appearedto be growing well in October• Insufficient herbicide applied• Brushcutters were used more extensively thanchainsaws in October, but why this would havean impact is unclear.Results from the basal bark trial were alsodisappointing, the reasons for which are unclear.In 2007, follow-up control was programmed forJuly, but was postponed until October to allowplants to recover from apparent frost stress. Acrew of three DEC staff undertook two days offoliar spraying using Nufarm Arsenal® XpressHerbicide (an imazapyr/glyphosate herbicide) inwater, which has been successfully used againsttamarisk in the USA.Effectiveness of this treatment is still beingmonitored but early indications are that it is animprovement on previous treatments used atLake Boonderoo. At the time of writing, a furtherround of spraying using Nufarm Arsenal® XpressHerbicide was programmed for April 2008.Work on tamarisk at Lake Boonderoo hascost at least $170,000 to March 2008, notincluding significant in-kind contributions fromthe Forrester family. Funding sources haveincluded the DEC Saving Our Species BiodiversityConservation Initiative, the DEC Remote RegionsNature Conservation Program and RangelandsNRM Coordinating Group.Up to 30 km of the Lake Boonderoo margin was infested with young tamarisk trees44 ATHEL PINE NATIONAL BEST PRACTICE MANAGEMENT MANUAL

Sylvia Clarke3. CASE STUDIESChainsaws and Access TM Herbicide were used to cut stump tamariskThe land managers involved in tamarisk controlat Lake Boonderoo will tailor their techniques inthe future so that teams of one cutter and twosprayers are on hand to ensure all stumps aretreated within 30 seconds of cutting. Monitoringof treated sites will continue, to track therecovery of indigenous vegetation followingtamarisk removal, evaluate the effectivenessof the control methods used and detect anyregrowth of tamarisk.In summing up the importance of tamariskcontrol at Lake Boonderoo, DEC’s GoldfieldsRegional Manager Ian Kealley says: “It is criticalto address the tamarisk problem early beforethe extent of the infestation makes it impracticaland beyond financial resources available. Thespecialist BCI/SOS and NRM projects allowedan immediate response and continual followupis critical. With ongoing work, control willbe achieved and this important wetland will beprotected”.45

Avon River, WALessons learned on smallflower tamarisk(Tamarix parviflora)Bethan Lloyd, Wayne Clarke and JonahGouldthorpeThey have been working since 1997 to cleardense infestations of smallflower tamarisk fromremnant riparian vegetation and the river banks,with mixed results. The Friends’ first attemptsinvolved chopping down the plants then trying todig the roots out, but the thickets of smallflowertamarisk were impenetrable and most regrewfrom roots or stumps remaining in the soil.The Friends’ Wayne Clarke explained thatattempts at foliar spray with glyphosate onlyburnt the tops off the plants resulting inregrowth, while stem injection was difficultto undertake and was also followed by lots ofregrowth. Cut stump treatment with glyphosatedidn’t work either.Bringing smallflower tamarisk under controlhas been a long term goal for Toodyay Friendsof the River. The Toodyay Friends of the RiverIncorporated (“the Friends”) is a landcare groupwho look after the Avon River in Toodyay,85 km east of Perth.By 2006, the Friends realised that they werenot making much progress with control of thesmallflower tamarisk and that the enormity ofthe thickets was far beyond the small volunteergroup’s capacity. The Friends applied for fundingthrough the Australian Government’s CommunityWater Grants to assist with smallflower tamariskremoval and other works along the Avon River.Smallflower tamarisk infests riparian vegetation and banks along the Avon River east of Perth46 ATHEL PINE NATIONAL BEST PRACTICE MANAGEMENT MANUAL

There was strong regrowth from roots and stumpsafter plants were cut downGaven Donegan, Project Officer for the Friends,was able to secure a front-end loader andoperator from the Shire of Toodyay for over oneweek. The machine was used to dig out thesmallflower tamarisk thickets during summer,and the debris was piled away from the floodzone to dry out and be burnt over winter.Prue DuftyToodyay Friends of the River waited for theexpected regrowth to occur, then attemptedto control the regrowth by foliar spraying withglyphosate.This was successful on plants which had regrownfrom small pieces of root or branch and hadlimited root systems, but did not kill those plantsgrowing from larger taproots. To control thelarger regrowth plants, the Friends cut back theregrowth, scraped back the bark to expose thecambium layer, then painted a triclopyr/picloramherbicide on to the exposed area.They continue to have success with this process,but estimate it will take a number of further visitsto the regrowth areas before they are completelysuccessful.Toodyay Friends of the River have learned a lotabout smallflower tamarisk control over theyears. Cut stump treatment of these weeds islabour intensive and is only practical where fewsmallflower tamarisk trees exist or many handsare available to do the work. Mechanical clearingcan offer a quick solution to dealing with denseor extensive smallflower tamarisk.3. CASE STUDIESA front-end loader can be used to dig out thickets during summer47

Debris was piled away from the flood zone and burnt over winterOn the other hand, mechanical clearing leads toabundant regrowth which needs to be treatedwith herbicides. Following-up this regrowth withfoliar spray is effective only where adequatefoliage (at least 1 m tall) is present to absorbenough herbicide to kill the root stock.It is difficult to put a dollar value on the workundertaken against smallflower tamarisk atToodyay, but many stakeholders have contributedsignificant time to the weed control. ToodyayFriends of the River typically put in 45 personhours per month on tamarisk removal through aregular monthly meeting, as well as individuals’time in between.This represents over 5000 person hours of workagainst smallflower tamarisk. The Northam officeof Western Australia’s Department of Waterorganised for a team of work camp prisonersto undertake manual removal of smallflowertamarisk from the river three days a week over athree month period.The Shire of Toodyay has also spent considerabletime removing smallflower tamarisk from the river.Department of Water has invested in herbicidesand diesel for smallflower tamarisk controlthrough its 12-year Avon Rivercare project.The persistence and dedication of ToodyayFriends of the River has been a key to successin controlling smallflower tamarisk on the AvonRiver. Volunteer groups such as the Friendscontribute thousands of person hours of weedcontrol as well as expert local knowledgeand continuity to control programs. Withouttheir commitment, labour-intensive weedcontrol, follow-up and monitoring in sensitiveenvironments would not be practicable oraffordable.Areas previously infested with smallflowertamarisk will need to be watched closely forregrowth for a number of years. Toodyay Friendsof the River have “given” each member a sectionof the river to monitor for regrowth, with thegroup to follow up collectively as needed.Wayne Clarke stresses the importance ofmonitoring and following up previously treatedareas of smallflower tamarisk: “The last thingwe want is to have spent all that money thengo back a few years later and find it all coveredagain”.48 ATHEL PINE NATIONAL BEST PRACTICE MANAGEMENT MANUAL

Kirk McDanielRoot ploughing and root raking were used to remove tamarisk in Unit 30Following tamarisk control, all trial areas werereplanted using local provenance indigenousplants.Vigorous regrowth of tamarisk from roots in Unit28 provided a number of lessons in successfultamarisk control, namely that: after treatmentwith herbicides, plants must be left undisturbedfor a least 12 months to let the herbicide do itswork; mechanical clearing must remove rootsas well as top growth to be successful, andregrowth from mechanical clearing usually needsto be followed up with more than one round ofherbicide treatment. Success in Unit 30 illustratedthat mechanical control methods which removeroots of tamarisk provide a high level of control.Experience with tamarisk control across theUSA indicates that long term regrowth andsurvival of tamarisk after treatment is reducedwhere indigenous trees are doing well. 66 Wherepracticable, establishing local provenance plantsand maintaining environmental conditions to suitplantings is an important element in long termfollow-up after weed control.Successful control programs against tamariskat Bosque del Apache National Wildlife Refugedemonstrate that, while control of Tamarixramosissima is difficult, it is achievable providedthat treated plants are monitored and followedup in the years after primary control.This case study is adapted from: Taylor JP,McDaniel KC. Restoration of saltcedar (Tamarixsp.)-infested floodplains on the Bosque delApache National Wildlife Refuge. WeedTechnology 1998;12:345-352.Kirk McDanielThe same site at Unit 28 following tamarisk removal50 ATHEL PINE NATIONAL BEST PRACTICE MANAGEMENT MANUAL

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