Eucalyptus ovata - Callitris oblonga (Black Gum) forest
Advice to the Minister for the Environment and Water Resources from the Threatened Species Scientific Committee (TSSC) on Amendments to the List of Ecological Communities under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act)
- 1. Name
- 2. Description
- 3. National Context
- 4. How judged by TSSC in relation to the EPBC Act criteria
- 5. Recommendation
- 6. Conclusion
- Conservation Advice
- Publications used to assess the nomination
1. Name
This ecological community was nominated under the name Eucalyptus ovata - Callitris oblonga Forest. This name was considered appropriate for use as the name of the national ecological community.
2. Description
The Eucalyptus ovata - Callitris oblonga Forest ecological community is a type of Eucalyptus forest with a shrubby understorey. This ecological community is characterised by:
- a Eucalyptus overstorey, typically made up of E. ovata, but in some areas it may be made up of by E. viminalis or E. amygdalina (Harris & Kirkpatrick 1991a; Zacharek 2000);
- a midstorey of Callitris oblonga subsp. oblonga; and,
- a shrubby understorey, of which Bursaria spinosa, Melaleuca gibbosa and Acacia dealbata are common components.
The ecological community is characterised by the association of Eucalyptus ovata and Callitris oblonga, and occurs in riparian (riverine) habitats. On alluvial flats the ecological community generally forms shrubby woodland, often in association with Melaleuca gibbosa. On rocky slopes this ecological community may lose its Eucalyptus overstorey due to topographical and soil factors, and form tall open shrubland with Callistemon pallidus. On rocky slopes, C. oblonga may therefore be the sole dominant, or co-dominant with eucalypts. Callitris oblonga is likely to be less dominant or co-dominant on the alluvial flats, where eucalypts, particularly E. ovata, become more dominant (Harris & Kirkpatrick 1991a).
This ecological community can vary in structure, for example it may occur as riparian forest, riparian scrub or as forest with a grassy understorey, reflecting a combination of the small-scale variations in topographic and disturbance effects of the riparian environment. The ecological community's composition has been degraded in some places and its structure has often been modified; the shrub layer may be absent due to overgrazing or Callitris oblonga absent due to frequent fire. Weeds also heavily infest some patches (Zacharek 2000).
There are some isolated remnants from which Callitris oblonga has been excluded, by fire or other disturbance. The absence of C. oblonga in these remnants is an index of the level of degradation of the ecological community. As a key species Callitris oblonga plays an important role in the ecological community, and its loss affects the habitat for other species. Remnants in which this species is absent are therefore considered degraded to such an extent that they are no longer part of the listed ecological community.
The most common and characteristic flora species of this ecological community, plus listed threatened flora associated with it, are listed in Table 1. Table 2 provides a list of fauna species recorded within the ecological community.
Underlying geology does not appear to limit the distribution of this ecological community, however, at a majority of sites the E. ovata - C. oblonga forest ecological community is found on substrates composed of modern floodplain sediments.
3. National Context
The Eucalyptus ovata - Callitris oblonga Forest ecological community is not formally listed under Tasmanian legislation, as Tasmania does not currently recognise threatened ecological communities.
Callitris oblonga subsp. oblonga (South Esk Pine) is a Tasmanian endemic in the Cupressaceae family. The species is listed as endangered under the Commonwealth EPBC Act, and as vulnerable under the Tasmanian Threatened Species Protection Act 1995. Eucalyptus ovata (Swamp Gum) occurs in NSW, Victoria, South Australia and Tasmania, and is neither listed nor regarded as threatened.
There are two other subspecies of C. oblonga, subspecies corangensis and parva, which have highly disjunct occurrences within NSW. The ecological communities in which these subspecies occur are excluded from the listed community, as E. ovata is not present.E. ovata - C. oblonga Forest has a disjunct distribution on the St. Pauls, Apsley, South Esk, Swan, Brushy, Cygnet and Wye Rivers and in associated habitats in the Midlands and East Coast of regions of Tasmania. An outlying patch occurs at Cataract Gorge in Trevallyn near Launceston and an atypical patch occurs south of Cranbrook on the East Coast on ironstone gravels, away from any watercourses. The only extensive patches of this community occur on the St. Pauls River and, to a lesser extent, the Apsley River (Nadolny & Benson 1993; Zacharek 2000).
The distribution of E. ovata - C. oblonga Forest is often discontinuous, reflecting land clearance, past disturbance regimes, topography and soil conditions. Presumably due to land clearance and past disturbance regimes, the ecological community is largely absent from the lower reaches of the South Esk and other river systems despite apparently suitable climatic, topographic and soil conditions (Harris 1989).
E. ovata - C. oblonga Forest is protected on the upper Apsley River in the Douglas Apsley National Park and on the South Esk River at Trevallyn State Reserve, however, less than 10% of the ecological community is securely reserved and these reserved areas do not include the larger patches of the ecological community (Zacharek 2000).
4. How judged by TSSC in relation to the EPBC Act criteria
The TSSC judges the ecological community to be eligible for listing as vulnerable under the EPBC Act. The justification against the criteria is as follows:
- Criterion 1 - Decline in geographic distribution
- Criterion 2 - Small geographic distribution coupled with demonstrable threat
- Criterion 3 - Loss or decline of functionally important species
- Criterion 4 - Reduction in community integrity
- Criterion 5 - Rate of continuing detrimental change
- Criterion 6 - Quantitative analysis showing probability of extinction
Criterion 1 - Decline in geographic distribution
The Eucalyptus ovata - Callitris oblonga Forest ecological community has experienced a decrease in its geographic distribution. The area occupied by the ecological community is estimated to have declined by between 20% and 50% in the last 200 years (Zacharek 2000).
It is likely that significant patches of this ecological community once existed between Avoca and the disjunct patch at Cataract Gorge near Launceston. There is a now a gap of 60 km in its distribution along the South Esk River. The lower reaches of this river have been extensively cleared for agriculture and have been subject to adverse fire regimes for much of the last 200 years (Zacharek 2000).
The geographic distribution of E. ovata - C. oblonga Forest has undergone a maximum decline of 50%, which does not meet the indicative threshold of this criterion. Therefore, this ecological community is not eligible for listing under this criterion.
Criterion 2 - Small geographic distribution coupled with demonstrable threat
The Eucalyptus ovata - Callitris oblonga Forest ecological community has a total range of 115 km from Cataract Gorge near Launceston to the Lower Swan River on the East Coast (Map 1). Currently the most extensive examples of this ecological community occur over a range of approximately 30 km from the upper reaches of the St. Pauls River to Avoca and along stretches of the lower reaches of the Apsley River. Smaller patches are found on the Swan and Cygnet Rivers, Hop Pole Creek (a tributary of the St. Pauls River) and on the South Esk River. The area of occupancy of the ecological community is approximately 548 hectares.
The ecological community occurs in discontinuous remnants throughout its distribution. The patch at Cataract Gorge near Launceston is over 60 km from the nearest other patch. Ongoing threats are likely to result in particular species being eliminated from small patches, with a high risk of the whole ecological community being significantly altered or eliminated. The elimination of small patches will further fragment the distribution of the E. ovata - C. oblonga Forest ecological community (Zacharek 2000).Weed infestation, fire and agricultural practices (such as clearing and grazing) constitute ongoing threats to the ecological community.
Heavy infestations of woody weeds, notably Ulex europaeus (Gorse), Crataegus monogyna (Hawthorn), Salix fragilis (Willow), Rosa rubiginosa (Briar) and Rubus fruticosus (Blackberry), frequent fire and stock grazing have degraded many patches in agricultural areas. Continued disturbance associated with agricultural management is likely to lead to the loss of many of these patches (Zacharek 2000).
Many of the patches of the ecological community on private land have been significantly altered by the invasion of introduced shrubs, particularly Gorse (Zacharek 2000). Gorse is a major threat to the ecological community. It has been identified as a weed of national significance, and while it is commonly associated with disturbed agricultural lands and degraded landscapes, it is also found in various native habitats including woodlands, grasslands, riparian areas and forests (Muyt 2001). Seed production in Gorse is large, with up to 10,000 seeds per square metre found under well-established patches. Seed viability exceeds 85% with seed remaining dormant in the soil for up to 30 years. Any disturbance around plants usually stimulates mass seed germination (Muyt 2001). Gorse forms dense, impenetrable thickets that eventually exclude all indigenous vegetation and prevent regeneration occurring. It acidifies the soil and produces nitrogen-rich leaf litter, which alters the nutrient composition of the soil, affecting the persistence of many indigenous species.
Thickets are a serious fire hazard, burning readily due to the large amount of dried material they accumulate (Muyt 2001).
The natural fire frequency of the habitat in which E. ovata - C. oblonga Forest occurs would have naturally been quite low (Harris & Kirkpatrick 1991b). A high fire frequency due to Gorse invasion and some agricultural practices has a significant impact upon the E. ovata - C. oblonga Forest ecological community.Gorse is difficult to control due to its prolific seed production, the seeds' high viability and long dormancy, and the problems associated with manual removal. Manual removal is difficult because of the spiny nature of the plant and its thicket-forming habit. It is therefore unlikely that the Gorse can be brought under control in patches of the ecological community in the medium-term future.
A considerable proportion of the E. ovata - C. oblonga Forest ecological community is subject to ongoing threats, although there is no precise information about the rate over which these threats are operating. The threats of weed infestation, frequent fire and agricultural practices such as grazing and clearing, are ongoing. Given the very restricted (less than 1000 ha) and discontinuous distribution of the ecological community, and the presence of long-term and persistent threats, restoration of the E. ovata - C. oblonga Forest ecological community is not likely to be possible in the medium-term future. Therefore, the ecological community is eligible for listing as vulnerable under this criterion.
Criterion 3 - Loss or decline of functionally important species
Callitris oblonga subspecies oblonga, is the only subspecies of Callitris oblonga that occurs in Tasmania, and is one of the major plant species that define the presence of the Eucalyptus ovata - Callitris oblonga Forest ecological community. The subspecies is listed as endangered on the Commonwealth EPBC Act and vulnerable on the Tasmanian Threatened Species Protection Act 1995.
The loss of C. oblonga is likely to have a significant affect on the structure of this ecological community. As a dominant species, C. oblonga plays an important role in the ecological community. It is often the only species in the midstorey and its loss would affect the habitat for other species (Zacharek 2000).
Historically, clearing has had a major impact upon C. oblonga in Tasmania. It is estimated to have declined by 20-50% in the last 200 years. While rates of clearing have decreased in recent years, the species is now under threat from weed invasion and fire (Zacharek 2000).
C. oblonga has a canopy seed bank, holding its seeds in woody cones close to the stem of the plant. Seeds are held in these capsules for many years, and are only released when the cones dry out after the branch supporting them dies. The species therefore requires disturbance resulting in the damage or death of trees to regenerate (Zacharek 2000).
Flooding is also important for the regeneration and dispersal of C. oblonga as it kills branches and trees, allowing the release of seeds. Floodwaters disperse seeds away from their original location, washing them downstream and depositing them up slopes and banks. The species can thereby colonise new areas (Zacharek 2000). There has also been some research showing that the species may be able to regenerate vegetatively (Harris & Kirkpatrick 1991b), further facilitating downstream colonisation as a result of flood events. Floods are unpredictable and usually infrequent enough to allow seedlings to grow to maturity before the next flood event.
Fires stimulate the release of Callitris oblonga seed and result in a large amount of localised recruitment. If a fire re-occurs in an area before the new individuals reach maturity and re-establish its canopy seed-bank, C. oblonga may be eliminated from that site. Therefore, an interval between fires of less than 5-10 years is likely to cause the local extinction of C. oblonga (Zacharek 2000).C. oblonga requires occasional flooding or fire events to regenerate, but is particularly susceptible to loss from an area by frequent fire.
Many patches of E. ovata - C. oblonga Forest have been heavily invaded by Gorse (Ulex europaeus). By increasing the frequency of fires, and out-competing C. oblonga seedlings, Gorse can have a significant impact on C. oblonga, and potentially bring about its local extinction. Gorse is very difficult to control and is unlikely to be eliminated from the ecological community in the medium-term future.
The continued loss of C. oblonga to frequent fire and weed invasion suggests that community restoration is not likely to be possible in the medium term future, therefore the ecological community is eligible for listing as vulnerable under this criterion.
Criterion 4 - Reduction in community integrity
Many key patches of Eucalyptus ovata - Callitris oblonga Forest have undergone, and are continuing to undergo a reduction in community integrity. Marked alteration of community processes follows weed invasion, particularly invasion by Gorse. The invasiveness of Gorse, and the dense infestations which often follow invasion, alter regeneration opportunities and promote high fire frequencies (Zacharek 2000).
Data from a survey of the ecological community in 1986/87 indicate that 56% of locations are degraded i.e. containing the weeds gorse, hawthorn, briar and blackberry or a combination of the four. A more recent, but less exhaustive survey of 52 km of river, undertaken in the mid-1990's, found approximately 60% of the sites were degraded. The headwater sites on the upper Apsley and Swan Rivers and near the junction of the Cygnet and Brushy Rivers are the only ones not degraded. The upper Apsley location is within Douglas Apsley National Park, the others are in forest or an intact riparian strip on private land.
Gorse forms dense, impenetrable thickets that eventually exclude all indigenous vegetation and prevent any regeneration of indigenous species occurring. It also acidifies the soil and produces nitrogen-rich leaf litter, which alters the nutrient composition of the soil so that it is no longer suitable for many indigenous species (Muyt 2001).
Thickets are a serious fire hazard, burning readily due to the large amount of dried material they accumulate (Muyt 2001). Inappropriate fire regimes will lead to a marked alteration of community structure. A high fire frequency will eliminate C. oblonga by killing trees prior to reproductive maturity and re-establishment of the canopy seed bank. Fire frequencies that are too low will limit regeneration opportunities for this and other plant species (Zacharek 2000). Repeated fires at short intervals modify the structure and composition of the whole community. The invasion of Gorse and other weed species across much of the ecological community's range has resulted, and will continue to result, in a substantial degradation of the ecological community, and disruption to the ecological community's processes. It is unlikely to be eliminated from the ecological community in the medium-term future. E. ovata - C. oblonga Forest is therefore eligible for listing as vulnerable under this criterion.
Criterion 5 - Rate of continuing detrimental change
There is no information addressing this criterion for Eucalyptus ovata - Callitris oblonga Forest. Therefore, this ecological community is not eligible for listing under this criterion.
Criterion 6 - Quantitative analysis showing probability of extinction
There is no information addressing this criterion for Eucalyptus ovata - Callitris oblonga Forest. Therefore, this ecological community is not eligible for listing under this criterion.
5. Conclusion
The Eucalyptus ovata - Callitris oblonga Forest ecological community meets Criterion 2 as vulnerable as its geographic distribution is very restricted and is coupled with ongoing demonstrable threat; Criterion 3 as vulnerable as it faces the loss or significant decline of a key species in the ecological community; and Criterion 4 as vulnerable as its integrity is being substantially reduced across most of its geographic range.
6. Recommendation
TSSC recommends that the list referred to in section 181 of the EPBC Act be amended by including in the list in the vulnerable category: ' Eucalyptus ovata - Callitris oblonga Forest'.
Conservation Advice
The Eucalyptus ovata - Callitris oblonga Forest, which occurs along rivers in the Midlands and East Coast regions of Tasmania (NHT regions of North Tasmania and South Tasmania), is very restricted (covering less than 1000 ha) and highly fragmented.
The key threats to the survival of the ecological community are weed infestation particularly from Gorse, Willow and Blackberry, fire, clearing and grazing and the resulting fragmentation into smaller, more vulnerable patches.
The priority recovery and threat abatement actions required for this ecological community are:
- manage weed invasion, prioritising control and elimination of gorse;
- manage fire impact through avoidance of activities that may ignite areas of this ecological community and adjacent Gorse thickets;
- prevent further clearing or fragmentation of the ecological community through local council zoning and/or the development of conservation agreements or covenants between landholders and the Tasmanian Department of Primary Industries, Water and Environment; and,
- improve regeneration through management of grazing including protective fencing, controlled stocking levels or rotational grazing systems.
This list does not encompass all actions that may be of benefit to this ecological community, but highlights those that are considered to be of the highest priority at the time of listing.
A recovery plan for this ecological community, developed by the Tasmanian Department of Primary Industries, Water and Environment, is in place in Tasmania for the period 2000-2004. It has not previously been adopted by the Commonwealth as the ecological community was not listed under the EPBC Act. An updated recovery plan is currently under consideration for adoption.
Priority for the development of recovery plan: recovery plan under consideration for adoption.
| Stratum | Species | Common name |
|---|---|---|
| Large trees | Eucalyptus ovata Eucalyptus viminalis |
Black Gum, Swamp Gum White Gum, Ribbon Gum |
| Small trees - large shrubs | *Callitris oblonga Allocasuarina verticillata Bursaria spinosa Acacia dealbata Banksia marginata Pomaderris apetala Acacia verticillata Callistemon pallidus Leptospermum lanigerum Melaleuca ericifolia Acacia mucronata Notelaea ligustrina Beyeria viscosa Melaleuca pustulata *Acacia axillaris |
South Esk Pine Drooping Sheoak Blackthorn Silver Wattle Silver Banksia Dogwood, Hazel Pomaderris Prickly Moses Lemon Bottlebrush Woolly Tea-tree Swamp Paperbark Variable Sallow Wattle Privet Mock-olive Pinkwood Midlands Wattle |
| Small - medium shrubs | Melaleuca gibbosa Leptospermum scoparium Hibbertia riparia Epacris impressa Micrantheum hexandrum Dodonaea viscosa Coprosma quadrifida Hakea microcarpa *Epacris apsleyensis *Epacris exserta * Spyridium lawrencei ~Bertya rosmarinifolia ~Pomaderris phylicifolia subsp. phylicifolia ~Spyridium parvifolium var. parvifolium |
Slender Honey-myrtle Manuka Stream Guinea-flower Common Heath Box Micrantheum Sticky Hop-bush Prickly Currant-bush Small-fruited Needlebush Apsley Heath South Esk Heath Small-leaf Spyridium Rosemary Bertya Narrow-leaf Pomaderris Australian Dusty Miller |
| Ground layer | Lomandra longifolia Poa labillardierei Bossiaea prostrata Schoenus apogon Lepidosperma elatius Acaena novae-zelandiae Gonocarpus tetragynus Astroloma humifusum Gonocarpus micranthus ~Pultenaea prostrata ~Persicaria decipiens ~Scleranthus fasciculatus ~Haloragis heterophylla ~Isoetes elatior ~Teucrium corymbosum |
Spiny-headed Mat-rush Tussock Grass Creeping Bossiaea Fluke Bogrush Bidgee-widgee, Biddy Biddy Native Cranberry Prostrate Bush Pea Slender Knotweed Spreading Knawel Variable Raspwort Tall Quillwort Forest Germander |
| * Listed as threatened under the EPBC Act and the TSP Act. ~ Listed as Rare or Threatened under the TSP Act only. |
||
| Class | Species | Common Name |
|---|---|---|
| Gastropods | ~Beddomeia krybetes | St Pauls Hydrobiid Snail |
| Insects | Anapheis java ~Antipodia chaostola leucophaea Costora delora Lingora aurata |
Chaostola Skipper |
| Amphibians | Crinia signifera Crinia tasmaniensis Limnodynastes dumerili Litoria ewingi |
Brown Froglet Tasmanian Froglet Banjo Frog Brown Tree Frog |
| Mammals | Antechinus minimus minimus Antechinus swainsonii swainsonii Bettongia gaimardi *Dasyurus maculatus maculatus Dasyurus viverrinus Macropus rufogriseus rufogriseus Ornithorhynchus anatinus Potorous tridactylus apicalis Pseudocheirus peregrinus viverrinus Sarcophilus harrisii Tachyglossus aculeatus Thylogale billardierii Trichosurus vulpecula fuliginosus Vombatus ursinus tasmaniensis |
Tasmanian Swamp Antechinus Tasmanian Dusky Antechinus Tasmanian Bettong Spotted-tail Quoll Eastern Quoll Bennetts Wallaby Platypus Long-Nosed Potoroo Common Ringtail Possum Tasmanian Devil Echidna Tasmanian Pademelon Brushtail Possum Common Wombat |
| Birds | Acanthiza chrysorrhoa Acanthiza ewingii Acanthiza pusilla Acanthorhynchus tenuirostris Accipiter cirrhocephalus cirrhocephalus Accipiter fasciatus fasciatus Aegotheles cristatus tasmanicus Alauda arvensis Anas castanea Anas gracilis gracilis Anas superciliosa superciliosa Anthochaera chrysoptera tasmanica Anthochaera paradoxa Anthus novaeseelandiae *Aquila audax fleayi Ardea novaehollandiae Artamus cyanopterus cyanopterus Biziura lobata Cacomantis flabelliformis prionuris Calyptorhynchus funereus xanthanotus Charadrius bicinctus Charadrius ruficapillus Chrysococcyx basalis Chrysococcyx lucidus plagosus Cinclosoma punctatum dovei Circus approximans gouldi Colluricincla harmonica harmonica Coracina novaehollandiae Corvus tasmanicus tasmanicus Coturnix ypsilophora ypsilophorus Cracticus torquatus cinereus Cuculus pallidus Cygnus atratus Dacelo novaeguineae novaeguineae Egretta alba Emblema bella Ephthianura albifrons Falco berigora tasmanica Fulica atra australis Gallinula mortierii Glossopsitta concinna Neophema chrysostoma Gymnorhina tibicen hypoleuca Haliastur sphenurus Hirundapus caudacutus Hirundo neoxena Hirundo nigricans nigricans Lichenostomus flavicollus Malurus cyaneus cyaneus Manorina melanocephala melanocephala Melanodryas vittata Melithreptus affinis Melithreptus validirostris Myiagra cyanoleuca Ninox novaeseelandiae leucopsis Pachycephala pectoralis Pardalotus punctatus Pardalotus striatus striatus Petroica multicolor boodang Petroica phoenicea Phaps chalcoptera Phaps elegans Phylidonyris melanops crassirostris Phylidonyris novaehollandiae Phylidonyris pyrrhoptera Platycercus caledonicus Platycercus eximius diemenensis Podargus strigoides strigoides Poliocephalus poliocephalus Porphyrio porphyrio melanotus Rhipidura fuliginosa albiscapa Sericornis humilis Strepera fuliginosa Strepera versicolor arguta Tadorna tadornoides Thinornis rubricollis Vanellus miles novaehollandiae Vanellus tricolor Zosterops lateralis lateralis |
Yellow-Rumped Thornbill Tasmanian Thornbill Brown Thornbill King Island Eastern Spinebill Collared Sparrowhawk Brown Goshawk Australian Owlet-Nightjar Common Skylark Chestnut Teal Grey Teal Pacific Black Duck Little Wattlebird Yellow Wattle Bird Richards Pipit Wedge-tailed Eagle White-faced Heron Dusky Wood-Swallow Musk Duck Fan-tailed Cuckoo Yellow-tailed Black Cockatoo Double-banded Plover Red-capped Plover Horsfields Bronze-Cuckoo Shining Bronze-Cuckoo Spotted Quail-Thrush Swamp Harrier Grey Shrike-Thrush Black-Faced Cuckoo-Shrike Forest Raven Brown Quail Grey Butcherbird Pallid Cuckoo Black Swan Laughing Kookaburra Great Egret Beautiful Firetail White-Fronted Chat Brown Falcon (Tasmanian) Eurasian Coot Tasmanian Native Hen Musk Lorikeet Blue-winged Parrot Australian Magpie (white-backed subsp.) Whistling Kite White-throated Needletail Welcome Swallow Tree Martin Yellow-throated Honeyeater Superb Fairy Wren Noisy Miner Dusky Robin Black-headed Honeyeater Strong-billed Honeyeater Satin Flycatcher Southern Boobook (Tasmanian) Golden Whistler Spotted Pardalote Striated Pardalote Scarlet Robin Flame Robin Common Bronzewing Brush Bronzewing Tawny-crowned Honeyeater New Holland Honeyeater Crescent Honeyeater Green Rosella Eastern Rosella (Tasmanian) Tawny Frogmouth Hoary-headed Grebe Purple Swamphen Grey Fantail White-browed Scrub Wren Black Currawong Grey Currawong (Clinking) Australian Shelduck Hooded Plover Masked Lapwing Banded Lapwing Silvereye |
| Reptiles | Niveoscincus ocellatus Niveoscincus pretiosus |
Ocellated Skink Tasmanian Tree Skink |
| Freshwater fish | Anguilla australis *Prototroctes maraena *Galaxias fontanus |
Short-finned Eel Australian Grayling Swan Galaxias |
| * Listed as threatened under the EPBC Act and the TSP Act. ~ Listed as Rare or Threatened under the TSP Act. |
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Publications used to assess the nomination
Harris, S. & Kirkpatrick, J.B. (1991a) The phytosociology and synecology of Tasmanian vegetation with Callitris in Banks, M.R. et al. (Eds) Aspects of Tasmanian Botany - A Tribute to Winifred Curtis. Royal Society of Tasmania, Hobart. 31: iii, 179-189.
Harris, S. & Kirkpatrick, J.B. (1991b) The distributions, dynamics and ecological differentiation of Callitris species in Tasmania in Australian Journal of Botany, 39, 187-202.
Forestry Tasmania (1999) Weed control in Tasmania's forests: information sheet 4.
Muyt, A. (2001) Bush invaders of South-East Australia: a guide to the identification and control of environmental weeds found in South-East Australia.
Nadolny, C. & Benson, J. (1993) The biology and management of the Pigmy Cypress Pine (Callitris oblonga) in NSW. NSW National Parks & Wildlife Service.
Zacharek, A. (2000) Community Recovery Plan Eucalyptus ovata - Callitris oblonga Forest. Department of Primary Industries, Water and Environment, Tasmania.