In many places on the Swan Coastal Plain Eucalyptus gomphocephala (tuart) woodlands are in decline or are degraded (Bulletin 1). This occurs for many reasons, including grazing by stock, weed invasion, logging and clearing. It is often a combination of these factors that gradually lead to a decline in the tuart populations

Dell, B.

Douglas, T.

Ruthrof, K.X.

So, T.

English

Research Repository

Eucalyptus gomphocephalaTuart declineR E S E A R C H  F I N D I N G S  April 2009Tuart Bulletin No.11 A series outlining key research findings associated with tuart health in south-west Western AustraliaRestoring degraded woodlandsKatinka Ruthrof, Tegan Douglas, So Thea, Bernard DellResearch into the decline of tuartis continuing. Meanwhile,methods of increasing the successof restoration efforts are beinginvestigated. The majorchallenges for restoration can besummarised in three categories(modified from Lamb 1994; Yatesand Hobbs 1997): 1) reducing the degrading factors(e.g. removing herbivores);2) ameliorating the ecosystemchanges (e.g. reducingcompaction and increasingwater availability); and 3) reintroducing local species (e.g.broadcast seeding or plantingseedlings, reintroducing faunaand fungi). In many places on the Swan Coastal Plain Eucalyptus gomphocephala (tuart) woodlands are in decline or aredegraded (Bulletin 1). This occurs for many reasons,including grazing by stock, weed invasion, logging andclearing. It is often a combination of these factors thatgradually lead to a decline in the tuart populations.Two major tuart woodlandareas are the focus ofrestoration trials: theYalgorup area south ofMandurah and the LudlowTuart Forest near Busselton.These trials are investigatingmethods of reversingecosystem degradation andreintroducing local plantspecies following themanagement of threateningprocesses. The methods include theaddition of site and plant treatmentsto increase the survival and growth ofseedlings. Treatments that have been trialed haveto fit certain criteria. They must be:• site appropriate (e.g. to ameliorateparticular soil conditions);11Figure 1: Survival of tuart seedlings at 11 months following the addition of 7treatments. HP = Harry Perry Reserve, Sarich = private property adjacent toYalgorup National Park, YNP = Yalgorup National Park. Figure 2: Growth and vigour responses of tuartseedlings to different restoration treatments.Healthy robust seedling (left) and nutrientstressed seedling (right).• inexpensive (i.e. affordable to land care groups, councils andother agencies);• easy to use (i.e. one does not need a licence); • applicable for large scalerestoration activities; and• applicable for use in other degraded sites (e.g. mine sites, old field restoration, infrastructureprojects, ex-pine plantations).Treatments that are currently beingtested include those that not onlyameliorate the factors inhibitingseedling establishment and growth,but also act to mimic conditions thatseedlings would have when theynaturally recruit. For example, episodicmass seedling recruitment oftemperate eucalypts, such as Tuart, canoccur following fire due to a numberof factors, such as higher levels ofavailable moisture and nutrients in thesoil (see Bulletin No. 7; Ruthrof 2002;Ruthrof et al. 2002; 2003).A collaboration of Government, research and industry partners supporting research into tree decline science and management in south-west Western Australia. www.tuarthealth.murdoch.edu.auAcknowledgementsThe restoration team would like tothank:• Ralph Sarich;• Department of Environment andConservation staff, particularly JohnCarter and Jason Foster;• Bemax Resources Limitedincorporating Cable Sands staffmember Brant Edwards;• Friends of Island Point members,particularly Lyn O’Brien;• City of Mandurah staff members,especially Lisa Wray;• Busselton Naturalists Club, particularlyBernie Masters; • Department of Environment andConservation Fairbridge Trainees; and• Forest Products Commission,especially Monica Dalton andMargaret Johnston.ReferencesBulletin 1: Why are the tuarts dying?Barber, P & Haswell, D. (2006). TuartHealth Research Group Lamb, D. (1994). Restoration ofdegraded forest ecosystems for natureconservation. In ‘Conservation Biology inOceania’. (Eds C. Moritz and J. Kikkawa.)pp. 101–114. (Surrey Beatty and Sons:Sydney.)Ruthrof, K. X., Yates, C. J. andLoneragan, W. A. (2002) The Biology ofEucalyptus gomphocephala DC. (Tuart).In: Tuart (Eucalyptus gomphocephala)and Tuart Communities (ed. B.J. Keigheryand Longman, V. M.). pp. 108-22.Wildflower Society of Western Australia(Inc.)Ruthrof, K. X. (2003) Seedling survival,growth and health of Eucalyptusgomphocephala (Tuart) seedlings inYalgorup National Park. Report for theDepartment of Conservation and LandManagement, Perth, Western Australia.Ruthrof, K. X., Loneragan, W.A. &Yates, C.J. (2003) Comparativepopulation dynamics Eucalyptuscladocalyx in its native habitat and as aninvasive species in an urban bushland insouth-western Australia. Diversity andDistributions. 9, 469-483. Yates, C. J & Hobbs R. H. (1997)Temperate Eucalypt Woodlands: aReview of Their Status, ProcessesThreatening Their Persistence andTechniques for Restoration. AustralianJournal of Botany. 45, 949–973.Tuart declineR E S E A R C H  F I N D I N G S  broadcast as seed. Treatmentsincluded ripping, the creation ofashbeds (Figure 3), and acombination of the two. The trial was established with thehelp of the Department ofEnvironment and Conservation andBemax Resources Limitedincorporating Cable Sands. Over3000 seedlings were planted in oneday with the assistance of some verykeen and capable members of theBusselton Naturalists Club and theFriends of Island Point. Early results suggest that:• the ashbed effect has asignificantly positive influence onseedling survival (Figure 4).However, although it isrecommended that ashbedscontinue to be used as part of therestoration process, most areasthat need to be restored will notable to be subject to the ashbedeffect. Therefore, other treatmentsthat provide similar results willneed to be found.  • Although ripping, in its currentform, has not produced significantresults regarding seedling survivalor growth, the use of lightploughing just prior to restorationactivities may be beneficial forproviding more safe sites for seedbroadcasting activities. Therefore,this site treatment is beingevaluated as part of the 2008restoration trial. With further monitoring and testingof sites, plant and seed treatments,these results will be able to drivecontinued improvement ofrestoration techniques, and willprovide management options forrestoration of other areas ofdegraded woodland in WesternAustralia.2009xxx-10-500Figure 4a and 4b: Growth and vigour responses of tuart and associatedunderstorey species on an ashbed (a) and on a ripped site (b) The Yalgorup trialsWith the help of private landowners, staff from the City ofMandurah, and members of theFriends of Island Point, over 2000tuart and associated understoreyspecies were planted or sown inareas fenced to exclude kangaroograzing. Treatments that were addedto the seedlings or seed included:local fungi inoculum, fertilizertablets, saturated water holdingcrystals, dry water crystals, zeolite,and a liquid chelating agent.  Early results of these trials suggestthat (Figure 1 and 2):• The use of planted seedlings ismore successful in terms ofsurvival than broadcast seed,particularly in tuart;• the use of fertilizer tabletstogether with a chelating agentsignificantly increases the survivaland growth of seedlings; and• water holding crystals are moresuccessful when applied in thewet state, rather than in dry form,as early rains cause the dry crystalsto swell and can cause the newlyplanted seedlings to ‘pop’ out ofthe soil and dry out.The Ludlow trials:The Ludlow forest has a long historyof degrading factors, including grazingby cattle and kangaroos and weedinvasion. As a result, many parts ofthe forest have very low levels of plantdiversity, with only a few understoreyspecies existing beneath themagnificent tuart canopy. A trial has been set up to determinethe effect of soil treatments on thegrowth and survival of various localcanopy and understorey species,both planted as seedlings and

Bulletin 1: Why are the tuarts dying?

Comparative population dynamics Eucalyptus cladocalyx in its native habitat and as an invasive species in an urban bushland in south-western Australia. Diversity and Distributions.

Seedling survival, growth and health of Eucalyptus gomphocephala (Tuart) seedlings in Yalgorup National Park. Report for the Department of Conservation and Land Management,

Restoring degraded woodlands

http://researchrepository.murdoch.edu.au/4606/

Restoring degraded woodlands

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