Review of Literature on Ironbark Ridges and Associated Lands

A Review of Literature on Ironbark Ridges and Associated Lands2004
FOREWORD
This report is dedicated to the memory of Jim Salmon and Barry Craze. It is the last publication that they both researched and wrote before they became ill. Jim and Barry devoted a great deal of their careers to the conservation of soil and the natural environment, and through this report they pass on the wealth of knowledge they both possessed on soils and the management of ironbark country in New South Wales. The text in this book is unchanged from what Jim and Barry originally compiled by the late 1990s. However, most of their original photos that were to be used in the book were lost and have been replaced by new ones.
~ Jim Salmon ~
J b a t
A
im Salmon was born in Echuca on 30 May 1952 and moved with his parents o Wagga at the age of five. After schooling in Wagga Wagga, he attended
agga Agricultural College where he graduated with a Diploma of griculture.
im started work with the Soil Conservation Service on 2 June 1974 at Parkes ith Kevin McPhee, who was then the District Soil Conservationist. After
raining with Kevin, Jim was transferred to the job of District Soil onservationist in Temora on 18 July 1977.
t was at Temora that Jim met Helen Hawkins. They married in January 1980 nd his three sons David, Scott and Jason were born there in the five years that ollowed.
n September 1989, he took up a property planning position at Temora which ransferred to the Temora District Manager position after David Priem moved to G or variations of it) until he medically retired on 19 July 2002. Sadly, Jim lost h way on 5 September 2002.
uring his career, Jim devoted time and effort to finding practical ways to improv ountry in the Temora district. He pioneered the development of rose clover to roduction on ironbark country. He designed and surveyed hundreds of kilometre ontrol soil erosion and drainage problems. Jim promoted conservation farming istrict through trail sites, field days, and collaborative work with the CSIRO, N mproved farm water supplies on many farms and helped landholders implement s unds through the NSW Rural Assistance Authority. Jim wrote several publicatio ountry and encouraged landholders to enhance and protect native vegetation on the
im was a ‘doer’ who was interested only in practical solutions. He was no ureaucracy so was often ‘cutting through the crap’ whether it was in his professio ptitude was better known than his nickname ‘Steptoe’. He could fix most things a rue conservationist at heart.
im’s contagious confidence and ability to translate the needs of the landscape in ranslated practical concepts into positive implementation. Substantial changes in l istrict since 1977, much of it attributable to Jim’s advice and dedication.
Review of Literature on Ironbark Ridges and Associated Lands
he did until May 1993, when he undagai. Jim stayed in that position is battle with melanoma and passed
e the management of ironbark ridge increase groundcover and improve s of graded banks and waterways to techniques throughout the Temora SW Agriculture and Landcare. He oil conservation works by accessing ns for the management of ironbark ir properties.
t a fan of too much planning and nal or personal life. His mechanical nd find a use for others’ ‘rubbish’, a
to simple language ensured that he anduse have occurred in the Temora
~ Barry Craze ~
Barry Craze was born in Henty on 20 September 1946. After schooling in Wagga Wagga, he attended the University of Sydney where he graduated in 1969 with an Agricultural Science Degree majoring in Soil Science. At the University of Sydney, he worked with Dr Brian Davey on improving the methods of measuring soil pH. While working with Dr Davey, he was one of the first soil scientists in NSW to use the measurement of soil pH in calcium chloride to estimate soil acidity. This is now the standard method.
He commenced work with the Soil Conservation Service at the Cowra Research Centre in 1969 working with Laurie McCathrey, Des Lang and later with Ian Packer and Greg Hamilton.
While stationed at Cowra, Barry worked closely with Rosemary Doust in the development of laboratory soil testing procedures as well as conducting several soil surveys in the Lachlan Valley including a survey for the Forbes Shire. He wrote many publications on soil chemistry and was one of the initial members Australian Laboratory Handbook of Soil and Water Chemical Methods (1992).
He moved to the Wellington Research Centre in 1985 as a Soils Research O automated soil sampling procedures in the laboratory for the new state wide S developed by John Lawrie. As well as laboratory work, he was the technical ed Landscape Reports from 1990 to 1997 and was a joint author for a chapter departmental publication Soils: Their Properties and Management. Barry later Office where he worked on the soil database until he took medical retirement in Ap in February 2000.
During his career, Barry became an expert in mine reclamation due to his extensiv of the few Soil Conservation Service staff who was instrumental in sampling soils gas pipeline route. He was also instrumental in setting up standard soil chemi automated procedures at both Cowra and Wellington Research Centres, particularl along the natural gas pipeline route. Barry was a mine of information on soil scienc to a question or problem, he knew where to go to find a solution. Outside work, B involved himself in a variety of interests. His interests in sailing, photography, some of the things he enjoyed over the years, with one notable accomplishment a history of Cowra.
A Review of Literature on Ironbark Ridges and Associated Lands
of the editorial committee for the
fficer and established many of the oil Survey Unit which was being
itor for the Soil Survey Unit’s Soil on soil physical properties in the
relocated to the Wellington District ril 1999. Sadly, Barry passed away
e work at Captains Flat and was one across NSW along the main natural stry laboratory testing methods and y to handle the many samples taken e and, if he did not know the answer
arry was a dedicated family man and native plants and local history were s the author of a book on the local
ACKNOWLEDGMENTS
The authors would have wished to acknowledge the valuable advice, constructive comments and previous work of Bill Johnston, Bill Semple and Ian Packer as well as the previous work of Des Lang, Brian Murphy and Greg Elliott. Many thanks to the following people: Mary Anne Sutherland and Dianne Whittle for typing the drafts; Chris Howarth and Greg Harris for taking new photos between 1998 and 2004; Chris for progressing the document from a draft to final publication; Helen Bonus for typing and layout; Anne Bell and Sue Irvine for professional editing; Tanya Mihe for assistance with figures, text layout and grammar and finally John Lawrie and David Priem for information about the late authors.
Enquiries should be directed to the following address:
Department of Infrastructure, Planning and Natural Resources PO Box 304 Temora NSW 2666 Telephone: (02) 6977 3310
The Department of Infrastructure, Planning and Natural Resources (DIPNR) and/or contributors accept no responsibility for decisions or results of actions made on the basis of the information contained herein, or for errors or omissions. Every effort was made to present accurate and updated information. Users are invited to notify the Department of any discrepancies contained in this report.
This document should be cited as:
Craze, B & Salmon, J (2004), A Review of Literature on Ironbark Ridges and Associated Lands, Department of Infrastructure, Planning & Natural Resources, Temora, NSW.
ISBN 0 7347 5439 6
Crown © 2004 Department of Infrastructure, Planning and Natural Resources
This report is copyright. Parts may be reproduced for the purpose of study and/or research provided acknowledgment of the source is clearly made.
CONTENTS 1. INTRODUCTION...................................................................................................................................................... 1
Associations............................................................................................................................................... 8 2.5.10 Eucalyptus crebra (Narrow-Leaved Red Ironbark) - Casuarina luehmannii (Bull Oak Association) ...... 8 2.5.11 Callitris endlicheri (Black cypress pine) - Ironbark Association .............................................................. 8
3. CURRENT STATUS OF THE IRONBARKS .......................................................................................................... 9
3.1 Effects of Clearing............................................................................................................................................. 9 3.2 Effects of Grazing.............................................................................................................................................. 9 3.3 Other Processes................................................................................................................................................ 10 3.4 Conserving What Remains .............................................................................................................................. 11
4.1 Eucalyptus sideroxylon (Red Ironbark) .......................................................................................................... 12 4.1.1 Climate .................................................................................................................................................... 12 4.1.2 Soils and Geology.................................................................................................................................... 12
4.2 Eucalyptus crebra (Narrow-Leaved Red Ironbark) ......................................................................................... 12 4.2.1 Climate .................................................................................................................................................... 12 4.2.2 Soils and Geology.................................................................................................................................... 13
4.3 Eucalyptus fibrosa ssp. fibrosa (Broad-Leaved Red Ironbark)....................................................................... 13 4.3.1 Climate .................................................................................................................................................... 13 4.3.2 Soils and Geology.................................................................................................................................... 13
5. SOILS ASSOCIATED WITH THE IRONBARKS................................................................................................. 15
5.3.1 Shallow Soils (Ucl.23, Ucl.43, Uml.43, Uml.33)..................................................................................... 22 5.3.1.1 Morphology of Shallow Soils ............................................................................................................22 5.3.1.2 Physical and Chemical Properties of Shallow Soils..........................................................................22 5.3.1.3 Groundcover of Shallow Soils on Ironbark Ridges ...........................................................................23
5.3.2 Red and Yellow Solodic Soils (Dr2.32, Dy2.32)...................................................................................... 24 5.3.2.1 Morphology of Red and Yellow Solodic Soils....................................................................................24 5.3.3.2 Physical and Chemical Properties of Red and Yellow Solodic Soils.................................................24
6. LAND USE ON THE IRONBARK LANDS........................................................................................................... 27
7.1 Inhibition of Plants by Ironbarks/Allelopathy ................................................................................................. 28 7.1.1 Chemical composition of Ironbark Leaves.............................................................................................. 29 7.1.2 Sources of Allelopathic Chemicals .......................................................................................................... 30 7.1.3 Stemflow .................................................................................................................................................. 30 7.1.4 Root Exudate ........................................................................................................................................... 31 7.1.5 Soil Concentration................................................................................................................................... 31 7.1.6 Conclusion............................................................................................................................................... 32
7.2 Water Repellence under Ironbarks................................................................................................................... 32 7.3 What is Water Repellence?.............................................................................................................................. 32
7.6.1 Wetting Agents......................................................................................................................................... 37 7.6.2 Deep Ploughing and Rotary Hoeing ....................................................................................................... 38 7.6.3 Furrow Seeding and Cultivating in the Rain........................................................................................... 38 7.6.4 Wettable Residues ................................................................................................................................... 38 7.6.5 Addition of Clay to the Surface ............................................................................................................... 38
8.1 General Principles............................................................................................................................................ 42 8.2 Early Trials (1961–1971)................................................................................................................................. 42 8.3 Further Species Trials (1976) .......................................................................................................................... 42
8.4.1.1 Establishment of Rose Clover............................................................................................................45 8.4.1.2 Establishment of Rose Clover in Ironbark Soils................................................................................45 8.4.1.3 Varieties ............................................................................................................................................45
8.4.2 Case Study ............................................................................................................................................... 45 8.5 General Recommendations and Conclusions for the Management of Ironbark Lands.................................... 47
REFERENCES ................................................................................................................................................................. 49
PHOTOGRAPHS Photograph 1. E. sideroxylon (red ironbark) is a medium sized tree between 10–25 m with trunk often dividing. ....................... 2
Photograph 2. E. sideroxylon (red ironbark) has a deeply fissured black bark. . .......................................................................... 3
Photograph 3. E. sideroxylon (red ironbark) - E. dealbata (tumbledown gum) association, Reefton. ............................................ 5
Photograph 4. Callitris glaucophylla (white cypress pine) - E. sideroxlyon (red ironbark) association, Dubbo............................. 6
Photograph 5. E. sideroxlyon (red ironbark) association, Springdale. ............................................................................................ 6
Photograph 6. E. sideroxlyon (red ironbark) - stringybark spp. association, Jindalee State Forest. ................................................ 7
Photograph 7. ronbark – western box association, Ariah Park........................................................................................................ 7
Photograph 8. Clearing has left fragmented populations of mature trees, Combaning. .................................................................. 9
Photograph 9. Overgrazing has altered soil conditions considerably, Ariah Park. ......................................................................... 10
Photograph 10. Badly designed dirt roads can cause erosion problems in ironbark country, Combaning State Forest. ................... 11
Photograph 11. Bad sheet erosion and gullies on ironbark soils, Combaning. ................................................................................. 21
Photograph 12. Badly sheet eroded waterway below an ironbark ridge, Ariah Park. ....................................................................... 22
Photograph 13. Gullies below ironbark ridges disrupting farming practices, Combaning................................................................ 23
Photograph 14. Poor groundcover under ironbarks is the result of toxins from bark and leaves affecting the germination of shrubs and grasses. .................................................................................................................................................. 23
Photograph 15. Gully walls expose stony layers below solodic soils, Combaning........................................................................... 24
Photograph 16. Bad gullies on red and yellow solodic soils at Springdale originally covered with E. sideroxylon (red ironbark). . 25
Photograph 17. Hardsetting and hydrophobic characteristics are critical in rendering these lands at Ariah Park susceptible to drought. ................................................................................................................................................................... 25
Photograph 18. Wide gully floor in eroded ironbark catchment, Reefton......................................................................................... 26
Photograph 19. Litter under Ironbarks suppressing establishment and persistence of grasses, legumes and shrubs. ....................... 29
Photograph 20. Strips of ironbark soils in Temora district sprayed with “Wetta Soil ®”. (Photo taken by Jim Salmon. Date unknown.)................................................................................................................................................................ 37
Photograph 21. Absorption banks in ironbark soils ponding water, Reefton. ................................................................................... 40
Photograph 22. Successful establishment of Rose Clover on ironbark soils in Temora district. ( Photo taken by Jim Salmon. Date unknown.) ....................................................................................................................................................... 41
Photograph 23. A well-managed waterway on “Tara”. .................................................................................................................. 46
Photograph 24. Dam and graded banks constructed on “Tara” to slow down the loss of water and to make it available for stock. (Photo taken by Greg Harris, 2003)........................................................................................................................ 46
TABLES Table 1. Eucalyptus sideroxylon (red ironbark) and E. crebra (narrow-leaved red ironbark) Occurrences Related to
Landscape, Lithology and Soils. Bathurst 1:250 000 report and map (Kovac, Murphy & Lawrie 1990) ....17
Table 2. Eucalyptus sideroxylon (red ironbark) Occurrence Related to Landscape, Lithology and Soils Goulburn 1:250 000 report and map (Hird 1990) ...........................................................................................18
Table 3. Eucalyptus sideroxylon (red ironbark), E. crebra (narrow-leaved red ironbark) and E. fibrosa ssp. fibrosa (broad-leaved red ironbark) Occurrences Related to Landscape, Lithology and Soils. Dubbo 1:250 000 map and report (Murphy & Lawrie 1998) .....................................................................................18
Table 4. Ironbark Species Occurrence Related to Landscape, Lithology and Soils. Singleton 1:250 000 report
Table 5. Ironbark Species Occurrences Related to Landscape, Lithology and Soils. Wallerawang 1:100 000
(Kovac & Lawrie 1991)..................................................................................................................................19
Table 6. Physical Soil Tests at Cookamidgera and Peak Hill .......................................................................................23
Table 7. Crop Yield and Two Tillage and Three Wetting Agent Treatments at Springdale, 1987...............................38
FIGURES
Figure 2. Angle of contact between soil and water droplet.............................................................................................34
Figure 3. Soil profile wetting pattern, and associated plant growth in a water-repellent soil. ........................................36
Figure 4. The associated soil surface wetting pattern, and plant growth in a water-repellent soil..................................36
Figure 5. Consol Lovegrass. ...........................................................................................................................................43
Figure 6. Yellow Serradella. ...........................................................................................................................................44
Figure 7. Rose Clover. ....................................................................................................................................................45
1. INTRODUCTION
Four different ironbark species, Eucalyptus sideroxylon (red ironbark/mugga), E. crebra (narrow-leaved red ironbark), E. fibrosa ssp. fibrosa (broad-leaved red ironbark) and E. fibrosa ssp. nubila (blue-leaved ironbark) are discussed and related to their floral community, soil, the lithology on which they grow, problems of allelopathy and water repellence.
E. sideroxylon (red ironbark) is a dominant native tree forming a discontinuous dry sclerophyll forest community in inland south-eastern Australia. The community occurs in areas receiving an average annual rainfall between 450–600 mm. Their occurrence in this area is related to geology and soils which are related to landform and erosion hazard.
The occurrence of other ironbarks, such as E. crebra (narrow-leaved red ironbark), E. fibrosa ssp. fibrosa (broad-leaved red ironbark) and E. fibrosa ssp. nubila (blue-leaved ironbark), is related to geology and soils. Similarly, these ironbarks are found on specific landforms with specific erosion hazards.
Forests of ironbarks occur on undulating plains, residual hills and low plateaux of Jurassic, Triassic, Permian, Carboniferous, Devonian and Silurian sediments of sandstone, shale or slate, or Ordovician quartzite, phyllite and schist, Mesozoic Sandstone (e.g. Pilliga Sandstone and Tertiary Sandstone).
The ridges give rise to large amounts of runoff and gully erosion is common below them. Revegetation will greatly reduce the amount of runoff. The presence of ironbarks is commonly regarded as indicating poor soils that are difficult to improve and manage. The surface soils are characteristically water-repellent, deficient in nutrients, shallow, rocky and poorly structured, often with dispersible subsoils.
The techniques for handling water-repellent soils are discussed. Strategies for the management of ironbark lands are also discussed as well as species and fertiliser trials conducted since 1961.
The cost-benefit for treatment and protection of the ridges and slopes is high as the productive capacity of country down slope is retained. Protection programs should capitalise on revegetation as well as soil and moisture retention. It is important to exclude or limit stock from the ridges while establishing a vegetative cover.
Recommending suitable pasture species for these ironbark areas is difficult. Early moisture stress, a short season, poor fertility, inadequate seed set and soil acidity are some of the problems a species would have to overcome to persist in these areas. Traditionally, recommendations were made for district averages without taking into account the great variations that occur over short distances in these lands i.e. only a fence might separate the solodic ironbark soils from the more productive red brown earths typical of the wheat-sheep belt.
Few of the many species trialled in past years have shown the ability to establish over a wide range of site conditions, survive the short and long-term droughts experienced, enhance infiltration due to vegetative mass, protect the soil against erosion or provide useful forage.
A Review of Literature on Ironbark Ridges and Associated Lands Page 1
2. CHARACTERISATION OF THE IRONBARKS
2.1 Eucalyptus sideroxylon (Red Ironbark/Mugga)
2.1.1 Growth Habit
Eucalyptus sideroxylon (red ironbark) is a medium-sized tree, 10–30 m high, with deeply fissured black bark; trunk often dividing (Costermans 1983). Often, the form of the trunk is rather poor, while the length does not usually exceed half the tree height. Crown-rounded to spreading, usually sparse, 10–20 m in width.
The former sub-species E. sideroxylon ssp. tricarpa is now classified as a separate species to E. sideroxylon (Calder & Calder 2002). The reclassified species E. tricarpa is a species of the open-forest. It is a better form and attains 25–35 m in height (Boland et al. 1984).
Photograph 1. E. s
lan Mature leaves - 60–
poi Flowers - 15– Capsules - 8–1 Seeds - reta
The specific name of th to the hardwood. Howe (Hall et al. 1970).
A Review of Literature on Ironb
ideroxylon (red ironbark) is a medium sized tree between 10–25 m with trunk often dividing.
ription
sistent on the trunk. y thick, deeply furrowed reddish brown to black, impregnated with kino deposits. ooth, whitish to greyish. 150 mm x 5–20 mm, opposite, becoming alternate, linear to oblong or narrow
ceolate, stalked, dull green to glaucous. 140 mm x 10–18 mm, alternate, lanceolate, stalked, dull green, grey or glaucous, ation densely reticulate; flowered axillary umbels on slender peduncles 15–20 mm long. 12 mm x 4–6 mm, ovoid to diamond-shaped on long, slender stalks, cap conical, nted or beaked, shorter than base. 20 mm across, white, pink, red or pale yellow, often profuse and conspicuous. 0 mm x 7–9 mm, barrel-shaped, on long stalks, valves enclosed. ined, grey-brown (Elliott & Jones 1986).
is species is based on the two Greek words sideros (iron) and xylon (wood) in reference ver, there are many eucalypts with much harder timber than that of botanical ironbarks
ark Ridges and Associated Lands Page 2
Photograph
2.2.2 Botanical Description
Bark - persistent Juvenile leaves - 80–125 m
green, ven Inflorescence - 4–11 flow Buds - 6–8 mm x Flowers - about 12 m Capsules - 5–7 mm x
shed annu
2.3.1 Growth Habit
both surfa Mature leaves - 140–180m
green on b Inflorescence - 7–11 flow
whitish, ca Flowers - about 20 m
A Review of Literature on Ironbark Rid
2. E. sideroxylon (red ironbark) has a deeply fissured black bark.
aved Red Ironbark)
ved red ironbark) is a medium to tall tree (20–30 m); trunk—solitary, usually ated, straggly (10–15 m) across.
on the trunk and branches, very hard, deeply-furrowed, light to dark grey. m x 10–20 mm, alternate, narrow-lanceolate, often falcate, dull green to bluish ation obscure. ered umbels arranged in a terminal panicle on peduncles about 10 mm long. 2–3 mm, club-shaped or diamond-shaped, cap short and conical. m across, white. 5–6 mm, cup-shaped or barrel-shaped, thin-walled, valves to rim level; seeds ally, grey-brown.
(Broad-Leaved Red Ironbark)
(broad-leaved red ironbark) is a medium to large tree (20–35 m); trunk—solitary, rse to dense (10–20 m) across.
on trunk and branches, deeply ridged, soft to hard, flaky, grey to black. m x 30–40 mm, alternate, broadly lanceolate to orbicular, stalked, grey-green on
ces, leathery, venation prominent. m x 30–50mm, alternate, broadly lanceolate, long-stalked, thick-textured, grey- oth surfaces, venation conspicuous. ered umbels usually arranged as terminal panicles, sometimes axillary, obconical, p horn-shaped, pointed, about as long as base. m across, white, often profuse.
ges and Associated Lands Page 3
Capsules - 5–12 mm x 5–10 mm, pear-shaped, valves slightly sunken to exserted. Seeds - retained, grey brown.
2.4 Eucalyptus fibrosa ssp. nubila (Blue-Leaved Ironbark)
2.4.1 Growth Habit
Eucalyptus fibrosa ssp. nubila (blue-leaved ironbark) is a medium sized tree (15–30 mm); trunk—solitary, straight; crown—elongated, sparse to dense (10–20 m) across.
Closely related to Eucalyptus fibrosa ssp. fibrosa but differing in the glaucous leaves at all stages and the glaucous buds and fruits; fruits of E. fibrosa ssp. nubila are often smaller (8 x 7 mm) than those of E. fibrosa ssp. fibrosa.
2.5 Associated Community Species
Eucalyptus sideroxylon (red ironbark) seldom forms pure stands and is usually associated with many other eucalyptus and some Callitris species (cypress pines). Common associated species for E. sideroxylon include E. polyanthemos (red box), E. microcarpa (grey box), E. melliodora (yellow box), E. nortonii (long-leaved box/large-flowered bundy), E. fibrosa ssp. fibrosa (broad-leaved red ironbark) and E. dwyeri (Dwyer’s red gum). Associated species for E. tricarpa include E. longifolia (woollybutt), E. muellerana (yellow stringybark), E. globoidea (white stringybark), and E. bosistoana (blue-leaved stringybark/coast grey box) (Boland et al. 1984).
Understorey layers, where they still exist, can be diverse, the species found also being determined by the soil depths, openness of the canopy and the aspect. According to Salmon (1993), they can include the following:
Acacia deanei (Deane's wattle/green wattle); Acacia verniciflua (varnish wattle); Acacia aspera (rough wattle); Acacia flexifolia (bent-leaved wattle); Acacia doratoxylon (currawang/coast myall/spearwood/lancewood; Acacia paradoxa (kangaroo thorn); Acacia lineata (streaked wattle); Bursaria spinosa (native olive); Calytrix tetragona (fringe myrtle); Bassia quinquecuspis (black rolypoly); Dodonaea viscosa ssp. cuneata (wedge-leaf hopbush); Eriostemon myoporoides (long-leaf waxflower); Exocarpos cupressiformis (cherry ballart/native cherry); Santalum acuminatum (sweet quandong); Grevillea floribunda (rusty spider flower); Olearia tenuifolia (shiny daisy bush); Cassia nemophila1 (desert cassia); Casuarina stricta (hill oak) and Dodonaea truncatiales (hop bush).
Usually, there is very little grass or low herbage cover because of toxins released from an ironbark’s foliage.
Native grasses include Stipa spp. (spear grasses), Stipa setacea (corkscrew grass), Danthonia spp. (wallaby grasses), Digitaria divaricatissima (umbrella grass) and Aristida spp. (three awn grasses/kerosene grasses).
2.5.1 Eucalyptus crebra (Narrow-Leaved Red Ironbark) Association
Eucalyptus crebra (narrow-leaved red ironbark) on its typical dry inland sites grows in woodland or open- woodland formation. It sometimes may be a dominant species but is commonly in mixture with one or more eucalypts and non-eucalypts. Of the latter, the most common is Callitris glaucophylla (white cypress pine), while there may also be Callitris endlicheri (black cypress pine), Casuarina cristata (belah), Casuarina luehmannii (bulloak), Acacia harpophylla (brigalow), Angophora costata (Sydney red gum/rusty gum) and Angophora floribunda (apple/rough-barked apple). Common eucalypt associates include E. maculata (spotted gum), E. citriodora (lemon-scented gum), E. tereticornis (forest red gum), E. trachyphloia (white bloodwood), E. propinqua and E. punctata (grey gums), E. moluccana and E. microcarpa (grey boxes), E. melanophloia (silver-leaved ironbark), E. dealbata (tumbledown red gum), E. fibrosa ssp. fibrosa (broad-leaved red ironbark) and E. polycarpa (long-fruited bloodwood).
2.5.2 Eucalyptus fibrosa ssp. fibrosa (Broad-Leaved Red Ironbark) Association
Eucalyptus fibrosa ssp. fibrosa (broad-leaved red ironbark) and E. fibrosa ssp. nubila (blue-leaved ironbark) occur mainly in open-forest formation. Species associated with E. fibrosa ssp. fibrosa include E. maculata (spotted gum), E. umbra (bastard white mahogany), E. beyeriani (Beyer’s ironbark), E. globoidea (white stringybark), E. paniculata (grey ironbark), E. drepanophylla (Queensland grey ironbark), E. sideroxylon (red
ironbark) and with ssp. nubila include E. maculata (spotted gum), E. trachyphloia (white bloodwood), E. watsoniana (large-fruited yellow jacket), E. pilligaensis (narrow-leaved grey box), E. tenuipes (narrow-leaved white mahogany) and Callitris species (cypress pines).
The particular association of trees varies and is dependent on locality, climate and geology.
2.5.3 Eucalyptus sideroxylon (Red Ironbark) - Eucalyptus dealbata (Tumbledown Gum) Association
In this type, red gum species (most commonly Eucalyptus dealbata (tumbledown gum less commonly Blakely’s red gum) are associated with ironbark species as co-dominants (Anon 1965; Specht et al. 1974; Bower & Semple 1993). E. sideroxylon (red ironbark) is probably the most common ironbark species in the association, and the E. sideroxylon (red ironbark) - E. dealbata (tumbledown gum) sub-type has been widely recognised in the southern parts of NSW where it occurs as a depauperate form of dry sclerophyll forest, and in the far west where it occupies broken country with skeletal soils (Beadle 1948). In more northern areas such as the Pilliga Scrub, E. crebra (narrow-leaved red ironbark) and E. fibrosa ssp. nubila (blue-leaved ironbark) tend to replace E. sideroxylon (red ironbark) in this type. Associated species in the type may include Angophora floribunda (apple/rough-barked apple), E. macrorhyncha (red stringybark), Callitris endlicheri (black cypress pine) and C. glaucophylla (white cypress pine) and various Acacia species (wattles).
Photograph 3. E. sid
2.5.4 Callitris glaucophyll
Eucalyptus sideroxylon (red (white cypress pine) (Anon. E. blakelyi (Blakely's red gu gum/rusty gum), Callitris end ‘association’ is largely confi Narrabri and Inverell districts areas.
A Review of Literature on Ironbark R
eroxylon (red ironbark) – E. dealbata (tumbledown gum) association, Reefton.
a (White Cypress Pine) - Eucalyptus sideroxylon (Red Ironbark) Association
ironbark) is a subdominant species in an association with Callitris glaucophylla 1965). Other species present may include Casuarina luehmannii (bulloak), m), Angophora floribunda (rough-barked apple), Angophora costata (Sydney red licheri (black cypress pine) and various boxes and wattles. The occurrence of the ned to the more northern parts of the state where it is common in the Dubbo, . It is reasonably common around Forbes where it occurs in shallow soils in hilly
idges and Associated Lands Page 5
Photograph 4. Callitris glauc
2.5.5 Eucalyptus sideroxylon
Eucalyptus sideroxylon (red ironb east of about the 375 mm isohye the Tablelands. The type norm composition. Despite this, a w following: E. dealbata (tumbledo (black cypress pine), E. macro Brachychiton populneus (kurrajo will be different.
Photograp
Eucalyptus sideroxylon (red iron parts of the western slopes from t shares dominance with stringyb caliginosa (broad-leaved stringyb scribbly gum), Angophora floribu Callitris endlicheri (black cypress
A Review of Literature on Ironbark Ridg
ophylla (white cypress pine)- E. sideroxlyon (red ironbark) association, Dubbo.
(Red Ironbark) Association
ark) is the dominant type found in the western districts in broken topography t (Anon. 1965). It extends eastward through the western slopes to the edge of ally occurs as a depauperate dry sclerophyll forest and it is usually pure in ide range of trees may occur as occasional associates. These include the wn gum), E. albens (white box), E. microcarpa (grey box), Callitris endlicheri
rhyncha (red stringybark), Angophora floribunda (rough-barked apple) and ng). Kurrajong can be found in proximity to ironbarks. However, the soil type
h 5. E. sideroxlyon (red ironbark) association, Springdale.
(Red Ironbark) - Stringybark spp. Association
bark) - stringybark spp. association occurs on shallow skeletal soils in various he south to the north (Beadle 1948; Anon 1965). E. sideroxylon (red ironbark) ark spp. usually E. macrorhyncha (red stringybark) in the south and E. ark) in the northern districts. Other associates may include E. rossii (inland nda (rough-barked apple), red gum spp. E. albens (white box) and associated pine) and Acacia spp. (wattles).
es and Associated Lands Page 6
Photograph 6. E. s
2.5.7 Ironbark - Western B
Ph
This is a mixed association i ironbark), E. melanophloia ( dominants with E. albens (wh more rarely, E. melliodora (y of at least six sub-types (Ano E. albens (white box) and E. box) and E. melliodora (yello
ideroxlyon (red ironbark) - stringybark spp. association, Jindalee State Forest.
ox Association
ograph 7. Ironbark - western box association, Ariah Park.
which various western ironbarks, notably Eucalyptus fibrosa (broad-leaved red ver-leaved ironbark) and E. crebra (narrow-leaved red ironbark), occur as co e box), E. pillagaensis (narrow-leaved grey box), E. microcarpa (grey box) and ow box) (Anon. 1965). Previous work in western NSW has shown the presence 1965): E. sideroxylon (red ironbark), E. pillagaensis (narrow-leaved grey box), icrocarpa (grey box); E. melanophloia (silver-leaved ironbark), E. albens (white box); E. crebra (narrow-leaved red ironbark) and E. albens (white box).
ges and Associated Lands Page 7
These sub-types are found throughout the western slopes and extending into the plains usually on rather excessively drained skeletal soils. The E. sideroxylon (red ironbark) - E. microcarpa (western grey box) has, in the past, been a high value forest type. Other Eucalyptus (eucalypts), Angophora (apples) and Callitris spp. (cypress pines) can occur as associates in this type which often has a dry sclerophyll forest structure.
2.5.8 Ironbark/Red Gum - Eucalyptus trachyphloia (Brown Bloodwood Association)
This association represents a poorer form of the ironbark-red gum association (Anon. 1965) occurring in the northern parts of the western slopes on usually shallow and infertile soils. Eucalyptus trachyphloia (brown bloodwood) is invariably present with a red gum, narrow-leaved red and/or E. fibrosa ssp. nubila (broad-leaved red ironbark) occurring as co-dominants. Other associates include E. rossii (inland scribbly gum) and occasional Callitris glaucophylla (white cypress pine). The type is common on the slopes of the Warrumbungle Ranges and extends to the Queensland border.
2.5.9 Callitris glaucophylla (White Cypress Pine) - Eucalyptus crebra (Narrow-Leaved Red Ironbark) Associations
Callitris glaucophylla (white cypress pine), Eucalyptus crebra (narrow-leaved red ironbark) and Casuarina luehmannii (bulloak) are the dominants in this type (Anon. 1965) although the oak may be absent. Other associated species might include the following: E. Blakelyi (Blakely’s red gum), E. fibrosa ssp. nubila (broad leaved red ironbark), Angophora floribunda (rough-barked apple), Casuarina cristata (belah) and Eremophila mitchellii (budda/false sandalwood). Frequently the Casuarina luehmannii (bull-oak) occurs in very dense clumps which hinder the establishment of the more desirable species.
The most widespread of the Callitris glaucophylla (white cypress pine) association occupies nearly 40% of the total area of managed cypress pine forests. They normally occur on sandy soils, frequently with an underlying hardpan. They are found in the northern half of the state from about Dubbo to the Queensland border and are particularly widespread in the western parts of the Pilliga Scrub.
2.5.10 Eucalyptus crebra (Narrow-Leaved Red Ironbark) – Casuarina luehmannii (Bull Oak Association)
This type is related to the Callitris glaucophylla (white cypress pine) - Eucalyptus crebra (narrow-leaved red ironbark) association (Anon. 1965) but is distinguished by the absence of cypress pine spp. other than as a very occasional stem. It is marked by the dominance of E. crebra (narrow-leaved red ironbark) with Casuarina luehmannii (bulloak), the latter being of smaller stature than the ironbark. Other associates may include red gum spp., E. melanophloia (silver-leaved ironbark) and certain boxes. This type occurs in the northern parts of the western slopes.
2.5.11 Callitris endlicheri (Black cypress pine) - Ironbark Association
This association is found mostly in the drier parts of their range on the slopes and tablelands. With Callitris endlicheri (black cypress pine) being associated with one of the other western ironbarks - Eucalyptus crebra (narrow-leaved red ironbark), Eucalyptus sideroxylon (red ironbark), E. fibrosa spp. nubila (blue-leaved ironbark), or E. melanophloia (silver-leaved ironbark). Other species which may also be present include Angophora costata (smooth-barked apple), Casuarina luehmannii (bulloak), E. trachyphloia (white bloodwood), red gum species and various western boxes. It occurs on an area with shallow, skeletal soils, particularly in the northern half of the state. Sub-types can be recognised, dependent upon the species of ironbark, which shares dominance with the black cypress pine.
3. CURRENT STATUS OF THE IRONBARKS
3.1 Effects of Clearing
The western slopes are the main cereal producing area of NSW and have been subject to extensive clearing since European settlement. This has resulted in widespread habitat loss and fragmentation. Estimates of clearing vary, but it is known that between 70–95% of the original native tree and shrub vegetation has been cleared since the mid 1800s (Murray Darling Basin Ministerial Council 1987). The clearing rate has been estimated at about 3,800 ha per year (Sivertsen 1993) and is generally clear felling.
Clearing of native vegetation is producing the greatest change in the box and ironbark lands of NSW (Sivertsen 1993). There is a preferential clearing of the box compared to ironbark. It is estimated by Robinson (1993) that there are 230,000 cubic metres of firewood burnt annually in Victoria and 80,000 tonnes burnt each year in the Australian Capital Territory (ACT). Most of the firewood used in the ACT comes from NSW and a lot of it is box and, to a lesser degree, ironbarks.
Clearing means the total destruction of habitat for most native plants and animals. While stating the obvious, we must realise that even although preconceived notions of natural distributions of species may no longer apply, the distribution of species in the box and ironbark lands has been significantly and permanently changed (Calder & Calder 1994).
Ph
Every time the remnant w shown that, for every 100 ha
3.2 Effects of Grazing
Grazing by domestic stock lands of NSW (Sivertsen 19 as important in the surviva components of native veget to the effects of grazing (Be
In the north of the box and Themeda australis (kangar unpalatable shrubs. The tre by the National Parks & W sites described in the north and/or rabbit faeces. These often support shrub layers o verges and fenced hilltops c
Grazing not only removes a
A Review of Literature on Ir
otograph 8. Clearing has left fragmented populations of mature trees, Combaning.
oodland is cleared or fragmented, the population decline continues. Bennett (1993) has of woodland that is cleared, between 1,000–2,000 birds permanently lose their habitats.
(sheep and cattle) and ferals (goats and rabbits) has affected change in the box and ironbark 93). The effects of grazing are perhaps more subtle than those of clearing but they are just l of many species. Grazing has extensively altered the native grass, shrub and small tree ation (Denny 1987 as cited in Benson 1991). Some plant extinctions are directly attributable nson 1991).
ironbark lands, grazing has caused a rapid decline in tall perennial native grasses (e.g. oo grass), followed by a slower decline in shorter native grasses and an increase in nd in the north is supported by recent work of Grice & Barchia (1992) and is also supported ildlife Service’s (NPWS) work in the wheatbelt (Sivertsen 1993). About 89% of the 1,200 ern and southern wheatbelt surveys show evidence of grazing in the form of sheep, goat sites tend to contain few native perennial grasses or palatable shrubs. However, they do f unpalatable species. In contrast, other sites with low grazing pressure, such as minor road ommonly have a diverse shrub and/or tall native grass layer.
dult plants, it also inhibits re-establishment of many species. There are no juvenile palatable
onbark Ridges and Associated Lands Page 9
woody species in most sites in the NPWS wheatbelt study areas. In some instances, there is abundant post-disturbance re-establishment but the overwhelming trend is little re-establishment among most tree and shrub species. However, not all plant species suffer decline under grazing regimes. The most notable exceptions are those that are poisonous and become known as woody weeds e.g. budda (Eremophila mitchellii), and Deane’s Wattle (Acacia deanei).
On some soils, grazing by original soil surface (for ex (1993) affect the habitat av water penetration regimes w survival of species locally a 1982).
Thus, grazing, like clearing they contain and the process
3.3 Other Processes
State forests comprise the l they provide important hab Most are grazed by either previously. Ironbark specie to encourage recruitment of canopy composition drama habitat. Native biota will re disappearing while others w
A number of factors such as regulation and managemen communities of the box and others (Siversten 1993).
The effects of these process have been extensively alte category. Figures suggest th time, the communities the Eucalyptus populnea (bimb (1982) suggest that decline the lack of re-establishment
These trends of declining sp
A Review of Literature on Ir
Photograph 9. Overgrazing has altered soil conditions considerably, Ariah Park.
hard-hoofed animals has considerably altered soil conditions. Compaction and loss of the ample, 60% of the wheatbelt sites showed obvious signs of erosion according to Siversten ailability for many small, ground-dwelling mammals and reptiles. Soil compaction alters ith soil moisture holding capacity and runoff. All these factors will ultimately affect the
nd the quality of groundwater in connected aquifers (Saunders et al. 1991; Adamson & Fox
, has significantly affected the box and ironbark lands of NSW, the plant and animal species es that support them.
argest remnants of natural vegetation in this part of NSW (Sivertsen 1993) and, although itat and refuge for many species, they often reveal considerably altered habitat regimes. domestic stock or goats, and hence have had their understoreys altered as described s have been selectively logged and, particularly in the west, box species have been removed the more commercially viable white cypress pine (Callitris glaucophylla) thus altering the tically. Hence, although very important, state forests cannot be equated with unaltered act to these changes in different ways with some becoming disadvantaged and declining or ill prosper (Siversten 1993).
urbanisation and its accompanying infrastructure (e.g. roads, railways and power lines), the t of waterways and the introduction of exotic plants and animals have altered the ironbark lands of NSW. The result is some species are favoured but there is a decline in
es are cumulative. Approximately 90% of the sites described in NPWS wheatbelt studies red. Many communities in the box and ironbark lands fall into the ‘extremely altered’ at while the canopy species in these communities may not appear to be at risk at the present
y characterise are indeed at risk. The long-term prognosis for canopy species such as le box/poplar box) and E. sideroxylon (red ironbark) may not be good. Adamson & Fox in these long-lived species is likely. Again, the wheatbelt work supports this concept given of canopy species over much of the study area.
ecies are attributable to the cumulative effects of the processes already discussed.
onbark Ridges and Associated Lands Page 10
Photograph 10. Badly
3.4 Conserving What Remains
“It is reasonable to suggest that some years, if current trends persist” acco true for the box and ironbark lands a (1993). “For whatever reasons, goo the original box and ironbark lands to
The challenge is to manage not just assemblages, pasture and farming la conserve not only native life forms b
Many legislative tools are available under the National Parks and Wildli (NSW). Provisions exist under plann in effect control development on des protect land for conservation. Anot ‘environmentally sensitive lands’ (C (NSW). Other legislative tools inclu (NSW) and the Threatened Species A
All these will form the backbone challenge is both urgent and vast conservation issues, and legislative t the active support of the human com far beyond the resources of govern Community-based initiatives such as this process and must become an managers, conservationists and ecol vegetation in the box and ironbark la strategies, it will be accomplished.
designed dirt roads can cause erosion problems in ironbark country, Combaning State Forest.
thing like half of all terrestrial species are likely to become extinct over the next 50 rding to RM May (as cited in Ulfstrand 1992). This alarming global trend seems s evidenced by the wheatbelt data presented above by Sivertsen (1993) and Traill
d or bad, we find ourselves with a small fragmented and highly altered remnant of manage” (Calder & Calder 1994).
species or plant communities, but a system which contains native flora and fauna nds, feral animals and exotic plants, towns and cities. Part of this challenge is to ut the processes which support them (Western 1992).
in NSW for the conservation and protection of lands. Reservation is an option fe Act 1974 (NSW), the Crown Lands Act 1989 (NSW) and the Forestry Act 1916 ing legislation for the formulation of State Environmental Planning Policies (which ignated lands) and Local Environmental Plans which can assist local government to her mechanism for the control of development and land use in rural NSW is the ategory ‘C’ protected lands) classification of the Soil Conservation Act 1938
de endangered species legislation under the National Parks and Wildlife Act 1974 ct 1995 (NSW).
of government initiatives to conserve natural environments. The conservation (Robinson 1993). No matter how good the legislation, it can never cover all ools are often difficult and expensive to apply. Legislation cannot succeed without munity. The conservation, revegetation and landscape reconstruction required are ment agencies and have become a community responsibility (Saunders 1994).
Landcare, Trees on Farms and Save the Bush are very important starting points for integral part of an ongoing exchange of information among landowners, land ogists. There is no easy and convenient recipe to follow for conserving remnant nds of NSW. However, the task is not impossible. By consolidating broad-based
idges and Associated Lands Page 11
4. DISTRIBUTION OF THE IRONBARKS
4.1 Eucalyptus sideroxylon (Red Ironbark)
Eucalyptus sideroxylon (red ironbark) extends from near Wangaratta in northern Victoria through the western slopes and plains of NSW, with some more easterly occurrences near Sydney and the Hunter Valley, to south-eastern Queensland as far as the Carnarvon National Park (Figure 1); the re-classified 3-flowered species E. tricarpa occurs in southern coastal NSW and is common in Gippsland and central Victoria (Brooker & Kleinig 1990). The overall latitudinal range is between 25–38¼ ºS and the altitudinal range is near sea level to about 1,000 metres above sea level.
4.1.1 Climate
The climate affecting the area where they grow is largely warm sub-humid but the species also extends to warm humid and warm semi-arid zones. The mean maximum temperature of the hottest month is in the range of 25– 33 ºC and the mean minimum of the coldest month is around 0–6 ºC. Frost frequency varies from nil or a few very mild frosts in the low altitude coastal areas to around 40 or more each year at higher altitude inland sites (e.g. on the western edge of the NSW northern tablelands). The mean annual rainfall varies from 350 to 650 mm, falling mainly during winter in Victoria but having a more or less uniform distribution in southern NSW, then grading to a moderate summer maximum farther north (Hall et al. 1990; Boland et al. 1984).
In Victoria, Eucalyptus tricarpa occurs mainly on the hilly and undulating country which forms the northern foothills of the Great Dividing Range and in near-coastal East Gippsland (Calder 1993), while in NSW E. sideroxylon extends to the slopes and plains.
Ironbarks can be found throughout the Murrumbidgee, Far Western, Central West, Lachlan, Barwon and Murray catchments. Within the Murray/Murrumbidgee Region, they occur in the vicinity of the towns of Albury, Henty, Wagga Wagga, Temora, Gundagai, Cootamundra, Yass and Young. They also occur around Cowra, Catombal Range of Orange and Wellington areas, Hervey Ranges and footslopes of Parkes (Schrader 1988) and Peak Hill areas, the Sappa Bulga Range south of Dubbo and north into the Pilliga sandstone scrub of Goonoo Forest and associated areas. Other areas are as follows: Coonabarabran, Gilgandra and Coolah, Stuart Town, Euchareena and Mookerawa areas of the Wellington District; Hill End, Hargraves, Gulgong and Ulan areas of the Mudgee District; and patches in the Bathurst and Lithgow Districts.
4.1.2 Soils and Geology
Eucalyptus sideroxylon (red ironbark) occurs on residual hills of Devonian and Silurian sediments of sandstone, shale or slate; Ordovician quartzite, phyllite and schist; Mesozoic sandstones (e.g. Pilliga sandstone) and Tertiary sandstone.
Soils are shallow, rocky and poorly structured. They are commonly lithosols or shallow stony yellow and brown solonetzic soils and red podzolic soils.
4.2 Eucalyptus crebra (Narrow-Leaved Red Ironbark)
Eucalyptus crebra (narrow-leaved red ironbark) has the widest north-south distribution of any ironbark and extends over more than 20º of latitude from Cape York Peninsula in Queensland to south of Sydney, NSW. In Queensland, it is common in a belt from 300 km to nearly 500 km wide reaching from the coast to just beyond the Great Dividing Range. In NSW, the principal occurrence is in the Baradine area, which is located on the edge of the western plains about 350 km from the sea (Figure 1). The overall range of latitude is between 13½–34¼ºS. The altitudinal range is from sea level to about 900 m (Boland et al. 1984).
4.2.1 Climate
The climate affecting the area where Eucalyptus crebra (narrow-leaved red ironbark) grows is largely warm sub- humid but the distribution also includes semi-arid and humid zones. Climatic conditions vary greatly, due mainly to the large latitudinal range. The mean maximum temperature of the hottest month is in the range 26 – 36 ºC with the mean minimum for the coldest month around 0–17 ºC. Frosts are absent or infrequent in coastal areas and in the northern (more tropical) part of the range, while elsewhere 5–50 per year may occur. The mean annual rainfall varies greatly from around 550 mm on the western edge of the distribution in NSW and southern Queensland to more than 2,000 mm in some northern coastal areas of Queensland. The rainfall distribution
grades from relatively even in the south to a slight to moderate summer maximum in northern NSW and southern Queensland, to a monsoonal type in northern Queensland with most precipitation between November and March/April.
This species commonly occurs on country of low relief on undulating plains and low plateaux. In the areas with higher rainfall, it is usually found on ridges and higher slopes.
Eucalyptus crebra (narrow-leaved red ironbark) grows on a wide variety of poor soils also, including siliceous sands, earthy sands, sandy loams, yellow and red podzolic soils, podzols and soloths. Sandstone and granite are both common parent materials. Lithology is Permian, Triassic and Jurassic sandstone, siltstone, shale and conglomerate. Carboniferous granite, granodiorite and adamellite are also common parent materials.
4.3 Eucalyptus fibrosa ssp. fibrosa (Broad-Leaved Red Ironbark)
Broad-leaved red ironbark extends from around Bodalla on the south coast of NSW to north of Rockhampton in Queensland, which is a distance of approximately 1,500 km (Figure 1). The latitudinal range is 22½–36¼ ºS while that for altitude is from near sea level to around 850 m (Boland et al. 1984).
4.3.1 Climate
Broad-leaved red ironbark occurs in the warm sub-humid to humid climatic zones, with the mean maximum temperature of the hottest month in the range 24–33 ºC and the mean minimum of the coldest month around 1–10 ºC. Frost occurrences vary from a few to up to 30 per year, as distance from the coast increases. Mean annual rainfall is around 650–1,500 mm, fairly evenly distributed in the southern part of the occurrence, gradually changing to a distinct summer maximum from about north of Taree (32 ºS).
Soil types are varied, ranging from relatively poor sandstone sites (lithosols) to fair quality loams, red and yellow podzolic soils and yellow-brown earths. Lithology is Carboniferous and Permian sandstone, conglomerate, siltstone and shale.
4.4 Eucalyptus fibrosa ssp. nubila (Blue-Leaved Ironbark)
Eucalyptus fibrosa ssp. nubila (broad-leaved red ironbark) appears to occur in two distinct areas, separated by around 200 km, both partially overlapping the distribution of ssp. fibrosa. The other occurrence extends westward from around Muswellbrook towards the Dubbo and Gilgandra areas in New South Wales (Figure 1). The latitudinal ranges for these areas are 25–29°S and 30¾–32½ °S respectively (Boland et al. 1984).
4.4.1 Climate
The climate is mostly warm sub-humid with the mean maximum temperature of the hottest month in the range 30–34 °C and the mean minimum for the coldest month is approximately 1– 4 °C; there are around 10–30 frosts annually. Mean annual rainfall is approximately 600–700 mm, with fairly even distribution in the south and a distinct summer maximum in the north.
Soil types are varied, ranging from relatively poor sandstone sites to fair quality, red and yellow podzolic soils, brown soloths and yellow earths. Lithology is Permian and Jurassic sandstone, siltstone, shale and conglomerate.
Figure 1. Distribution of Ironbarks from Brooker & Kleinig (1983).
Eucalyptus crebra Eucalyptus sideroxylon (Narrow-leaved Red Ironbark) (Red Ironbark)
Eucalyptus fibrosa spp. nubila (Blue-leaved Ironbark)
A Review of Li
terature on Ironbark Ridges and Associated Lands Page 14
5. SOILS ASSOCIATED WITH THE IRONBARKS
5.1 General Effects of Soils on the Distribution of Tree Species
Many of the eucalypt species have discrete natural distributions, some of which are associated with soil groups. For example, Moore (1953), working in the Riverina, observed that tumbledown red gum and Eucalyptus sideroxylon (red ironbark) occurred on lithosols, white box occurred on red and yellow podzolic soils and chocolate soils and inland grey box occurred on red-brown earths. Biddiscombe (1963), working in the Macquarie region, found that in mixed associations of narrow-leaved, and E. fibrosa ssp. nubila (broad-leaved red ironbark), E. crebra (narrow-leaved red ironbark) grew on sandy solodic soils and E. fibrosa ssp. nubila (broad-leaved red ironbark) grew on sands and gravelly sands. In mixed associations of river red gum and grey box or E. pilligaensis (narrow-leaved grey box), river red gum grew in recent alluvial soils, narrow-leaved grey box grew in stony colluvial soils or solodized solonetz soils and grey box grew in solodized solonetz soils, red-brown earths, red brown sands or sandy loam soils. Biddiscombe (1963) also observed that white box grew in the heavy clay soils (black earths and brown calcareous clays).
Particular soil properties are also known to influence the occurrence of different eucalypt species. Elliott (1986) observed that in the Muswellbrook area, E. dawsonii (slaty box) occurred in grey brown solodic soils that were structurally unstable. He also noted that, near Liddell, E. maculata (spotted gum) occurred on locally humic red and yellow solodic soils that otherwise support grey box. Moore (1959) indicated that significant differences in the nutrient status of soils of sharply defined eucalypt communities existed. Feller (1980) measured different soil nutrient levels and edaphic properties associated with E. regnans (mountain ash) compared with a mixed stand of E. obliqua (messmate stringybark) and E. dives (broad-leaved peppermint).
Further to these factors of nutrients and moisture, Moore (1960) clearly demonstrated that scribbly gum (E. rossii) and yellow box reacted to their total environment, including competing species. Ellenberg (1953, 1956, 1958), as cited by Moore (1960), distinguished between physiological tolerance and ecological tolerance and concluded that the relative competitive ability of a species varies with the environment, including competing species.
Near Ulan, NSW, Elliott (1986) observed a clear demarcation between stands of E. crebra (narrow-leaved red ironbark) (including small numbers of black cypress pine) and Acacia mearnsii (black wattle) and grey box, including small numbers of E. tereticornis (forest redgum) growing on apparently similar soil types. There were no discernible differences in physical features (such as surface topography, slope length, aspect or drainage) among the forest types which adjoined on a single discrete hillslope section.
Both species are known to be favoured by local drainage characteristics, which produce relatively humid conditions. E. crebra (narrow-leaved red ironbark) dominates over E. sideroxylon (red ironbark) in such conditions (Biddiscombe 1963) and grey box over white box (Moore 1953).
Elliott (1986) carried out a comparison of these spatially distinct forest types. He attributed these differences to the two stands he found. The grey box dominant vegetation type occurred on soils which had higher available moisture storage capacity, greater soil strength and bulk density, higher pH levels and higher levels of nutrients, other than nitrogen and phosphorus, than soils which supported E. crebra (narrow-leaved red ironbark) dominant vegetation.
In 1993, Prosser et al. compared the pH (1:5, soil:0.01 M CaCI2) and easily extractable forms of Al between forest and pasture soils near Bendigo, Victoria. The forest was dominated by E. macrorhyncha (red stringybark), E. microcarpa (grey box) and E. sideroxylon (red ironbark). The soils were shallow lithosols or gradational soils developed on Ordovician sandstone and shales.
The results show that perennial pasture growth is required in this region to reduce groundwater recharge as part of the management of dryland salinity, but pasture growth can be inhibited by Al and Mn toxicity as a consequence of soil acidification. Both forest and pasture soils were found to be acidic (mean pH of 4.0 and 4.3 respectively) and A1 concentrations are sufficient to anticipate toxicity to sensitive species. The forest site was cleared of timber over 50 years ago, and has since acidified by 63 kmol H+ ha-1, which is accounted for by organic anion accumulation in the forest regrowth. The forest soil has lower concentrations of extractable A1 for a given pH, and more A1 complexed to organic matter, even though forest and pasture soils have equal amounts of organic carbon. The different A1 concentrations in forest and pasture soils are accounted for by a lag in A1 response to acidification and greater complexation of A1 with organic matter in the forest soil.
5.2 The Distribution of the Ironbarks in Relation to Soils and Geology
Using Soil Landscape maps and texts produced by the Department, data on vegetation, geology and soil relationships could be easily extracted:
1. The Bathurst 1:250 000 soil landscape map and text by Kovac, Murphy & Lawrie (1989) provides 21 soil landscapes which indicate the growth of Eucalyptus sideroxylon (red ironbark). Capertee has reference to E. crebra (narrow-leaved red ironbark). See Table 1.
2. The Goulburn 1:250 000 soil landscape map and report by Hird (1990) provides three soil landscapes which indicate the growth of E. sideroxylon (red ironbark). See Table 2.
3. The Dubbo 1:250 000 soil landscape map and report by Murphy et al (1998) provides gives 15 soil landscapes which indicate the growth of E. sideroxylon (red ironbark). Thirteen have E. crebra (narrow-leaved red ironbark) and eight have broad-leaved red ironbark. See Table 3.
4. The Singleton 1:250 000 soil landscape map and report by Kovac & Lawrie (1991) provides 10 soil landscapes which indicate the growth of E. sideroxylon (red ironbark). Thirty-one have E. crebra (narrow-leaved red ironbark), 12 have E. fibrosa ssp. fibrosa (broad-leaved red ironbark) and 2 landscapes have nondescript ironbark communities. See Table 4.
5. The Wallerawang 1:100 000 soil landscape map and report by King (1993) provides four soil landscapes which indicate the growth of E. crebra (narrow-leaved red ironbark). Three have with E. fibrosa ssp. fibrosa (broad leaved red ironbark) and one has a E. beyeri (Beyers ironbark) community. See Table 5.
Tables 1-5 (see over) indicate the predominant lithologies as being Lower-Middle-Upper Devonian metasediments and some granite, granodiorite, rhyolite and andesite. There are Upper Silurian to Lower Devonian rhyolites, Lower Ordovician andesite, Mesozoic sandstones and Tertiary ferruginous sandstone and basalt.
E. sideroxylon (red ironbark) grows most commonly on shallow, skeletal sands, bards and lithosols on Devonian metasediments. Shallow red podzolic soils, brown podzolic soils and yellow podzolic soils are also common on these lithologies. Non-calcic brown soils, euchrozems, red podzolic soils and skeletal sands are found on Devonian granites, granodiorites and rhyolites. Red, yellow and brown solodic soils are found on Permian shale, sandstone and conglomerate. Siliceous sands and red soloths have developed on Tertiary ferruginous sandstone.
E crebra (narrow-leaved red ironbark) grows most commonly on siliceous sands, lithosols, yellow, red and brown podzolic soils on Devonian, Permian, Triassic and Jurassic sandstone, siltstone, shale and conglomerate. Earthy sands, siliceous sands and podzols on Carboniferous granite, granodiorite and adamellite.
E. fibrosa (broad leaved red ironbark) grows most commonly on lithosols, yellow and red podzolic soils on Carboniferous and Permian sandstone, siltstone, mudstone, shale and conglomerate; yellow earths, soloths and solodic soils on Jurassic shale and sandstone.
The most common soils and lithologies where E. fibrosa ssp. nubila (blue-leaved red ironbark) grows are red and yellow podzolic soils, brown soloths and yellow earths on Permian and Jurassic sandstone, siltstone, shale and conglomerate.
Table 1. Eucalyptus sideroxylon (red ironbark) and E. crebra (narrow-leaved red ironbark) Occurrences Related to Landscape, Lithology and Soils. Bathurst 1:250 000 report and map (Kovac, Murphy & Lawrie 1990).
Landscape Unit Lithology Soils Red ironbark community associated with: Brinsley RP-by Tertiary, Trachyte, Triassic red podzolic soils Brogans Creek NY-bo Shale, siltstone, quartzite, tuff, limestone yellow podzolic soils Canomodine SL-ce Lower Devonian Limekilns group black
shale, siltstone, limestone, conglomerate shallow, skeletal sands, loam, shallow brown podzolic soils
Catombal SL-cs Upper Devonian Black Rock subgroup sandstone, conglomerate, red and green shale
shallow red podzolic soils, shallow skeletal sands, loam
Cowra RP-cw Middle Devonian Cowra granodiorite – granodiorite
red podzolic soils, siliceous sands, non calcic brown soils
Crowther YP-cr Middle Devonian Gumble and Young Granites - granite
skeletal sands, brown podzolic soils, yellow podzolic soils
Cudal E-cl Tertiary basalt - Basalt euchrozem Currumbenya RP-w Lower Silurian Canowindra Porphyry
shale, limestone, quartz feldspar porphyry shallow loam, red podzolic soils
Dulladerry RS-du Lower Devonian Dulladerry Rhyolite – rhyolite
red podzolic soils, yellow podzolic soils, brown podzolic soils
Greydene RS-gd Lower Devonian rhyolite and alluvium – rhyolite, colluvium
non-calcic brown soils, red solodic soil
Grove Creek TR-gc Upper Ordovician to Lower Silurian Millambri formation limestone, siltstone, feldspathid greywacke, conglomerate
terra rossa soils, skeletal sand and loam
Gumble SS-gu Middle Devonian Gumble and Young Volcanics granite
red podzolic soils, non-calcic brown soil, siliceous sands
Kangaroo Flat NKB-kf Middle Devonian Granodiorite – granodiorite
siliceous sands, non-calcic brown soil, red podzolic soil
Killonbutta SS-ki Tertiary Ferruginous Sandstone – ferruginous sandstone
siliceous sands, red soloth
skeletal sands and loams
Mandagery SL-my Upper Devonian Nangar subgroup – sandstone, siltstone, shale, fine conglomerate
skeletal sand and barns, non calcic brown soil
Molong E-mo Lower Ordovician Cargo - andesite – andesite, tuff, slate
euchrozem, non-calcic brown soil
Nangar NKB-na Upper Devonian Nangar Subgroup – siltstone, sandstone, shale, fine conglomerate
skeletal sand and loam, non-calcic brown soil
Woodstock E-wo Lower Ordovician Cargo and Walli Andesite - andesite, tuff, slate
skeletal loam or sand euchrozem, red podzolic soil
Wyangala SS-wy Middle Devonian Wyangala Batholith granite
siliceous sands, red podsolic soils, non calcic brown soils
Yahoo Peaks SL-yp Upper Silurian to Lower Devonian Dulladerry Rhyolite - rhyolite
shallow skeletal sands, red podzolic soils
E. crebra (narrow-leaved red ironbark) community associated with: Capertee YP-cp Permian siltstone, shale, sandstone,
conglomerate yellow podzolic soils, brown podzolic soils
Table 2. Eucalyptus sideroxylon (red ironbark) Occurrence Related to Landscape, Lithology and Soils. Goulburn 1:250 000 report and map (Hird 1990).
Landscape Unit Lithology Soils Illunie YS-il Lower Devonian Duoro volcanics and
Illunie Rhyolite - rhyolite, porphyry lithosols, yellow earth
Nangar NKB-na Upper Devonian Nangar subgroup Metasediments, siltstone, sandstone, shale, fine conglomerate
skeletal soils, non-calcic brown soils
Pipe Clay 55-pc Lower Devonian Illunie Rhyolite colluvium
siliceous sands
Table 3. Eucalyptus sideroxylon (red ironbark), E. crebra (narrow-leaved red ironbark) and E. fibrosa ssp. fibrosa (broad-leaved red ironbark) Occurrences Related to Landscape, Lithology and Soils. Dubbo 1:250 000 map and report (Murphy & Lawrie 1998).
Landscape Unit Lithology Soils Red ironbark community associated with: Brogans Creek YP-bo Lower Devonian shale, siltstone, quartzite,
tuff, limestone yellow podzolic soils
Catombal SL-cs Upper Devonian sandstone, conglomerate, red and green shale
red podzolic soils, shallow sandy soils
Curumbenya RP-cu Silurian quartz biotite porphyry, shale red podzolic soils, shallow loams Dulladerry RS-du Devonian banded rhyolite yellow podzolic soils, red podzolic soils,
skeletal sand and loam Greydene RS-gd Devonian Rhyolite non-calcic brown soils, earthy sands Killonbutta 55-ki Tertiary sandstone Siliceous sands, red soloth, yellow soloth Larras Lee NKB-ll Upper Devonian siltstone, shale, sandstone,
conglomerate yellow podzolic soils, non-calcic brown soils, shallow sands
Molong E-mo Ordovician andesite, tuff, slate, limestone euchrozem, yellow podzolic soils, non calcic brown soils
Mount Bara SL-ba Devonian sandstone, phyllite, slate, rhyolite, dacite, tuff, shale, conglomerate
shallow soils, red soloth, yellow soloth, yellow solodic soil
Yahoo Peaks SL-yp Devonian, rhyolite shallow sands, loams, red podzolic soils Red ironbark and E. crebra (narrow-leaved red ironbark) community associated with: Aarons Pass ES-ap Carboniferous, hornblende granite and
granodiorite earth sands, siliceous sands, yellow soloths and podzols
Rylstone 55-ry Carboniferous rhyolite and dacitic tuff siliceous sands, podzols, red podzolic soils, yellow podzolic soils
Red ironbark, E. crebra (narrow-leaved red ironbark) and broad-leaved red ironbark community associated with: Balladoran ES-bn Jurassic Pilliga sandstone, conglomerate,
siltstone, shale earthy sands, red earths, yellow earths, yellow solodic soils, shallow sandy soils
Goonoo ES-gn Jurassic sandstone, conglomerate, siltstone, shale
earthy sands, siliceous sands, red earths, yellow earths, grey earths, yellow solodic soils
E. crebra (narrow-leaved red ironbark) community associated with: Capertee YP-cp Permian sandstone, siltstone and
conglomerate yellow podzolic soil
siliceous sands, red podzolic soils, soloths
Dexter SL-dx Earthy sands, shallow siliceous sands, yellow solodic soils
Home Rule SS-hr siliceous sands, podzols, yellow podzolic soils, soloths
Munghorn Plateau SS-mp Triassic sandstone, wollar, sandstone, conglomerate, mudstone
yellow earths, yellow soloths, siliceous sands
Landscape Unit Lithology Soils Rouse SS-rs Carboniferous granite, adamellite,
granodiorite siliceous sands, podzols, yellow solodic soils
E. crebra (narrow-leaved red ironbark) and broad-leaved red ironbark communities associated with: Barigan Creek YP-bc Permian shale, sandstone conglomerate,
chert, torbanite, sandstone, red-brown and green mudstone
yellow podzolic soils, red podzolic soils
Crowee YE-cr Jurassic shale, carbonaceous shale, ferruginous and lithic sandstone
yellow earths, soloths
Turill ES-ti Jurassic shale, sandstone, mudstone, conglomerate
red earths, earthy sands, siliceous sands, yellow podzolic soils, grey podzolic soils, soloths
Broad-leaved red ironbark community associated with: Collingwood RP-cg
Erudigerie YP-er
red podzolic soils, yellow podzolic soils
Ulan YP-ul Permian, shale, sandstone, conglomerate, chert
siliceous sands, yellow-brown earths, yellow podzolic soils
Table 4. Ironbark Species Occurrence Related to Landscape, Lithology and Soils. Singleton 1:250 000 report (Kovac & Lawrie 1991)
Landscape Unit Lithology Soils Red ironbark community associated with: Growee SC-ge Permian shale, sandstone, conglomerate red solodic soils, yellow solodic soils,
brown solodic soils Red ironbark and E. crebra (narrow-leaved red ironbark) community associated with: Braxton YP-bx Permian sandstone, shale yellow podzolic soils, yellow soloth, red
podzolic soils Castle Rock SC-ck Permian sandstone, shale, conglomerate yellow solodic soils Colonel E-ch Carboniferous conglomerate, lithic
sandstone, tuff lithosols
euchrozems, non-calcic soils
Segenhoe E-sg Upper carboniferous conglomerate, sandstone, shale
euchrozems, red solodic soils, earthy sands
Red ironbark, E. crebra (narrow-leaved red ironbark) and broad-leaved red ironbark community associated with: Balladoran ES-on Jurassic sandstone, conglomerate, shale,
siltstone shallow sands, yellow earths, red earths, earthy sands
Goonoo ES-gn Jurassic sandstone, conglomerate, siltstone, shale
earthy sands, siliceous sands, yellow earths, yellow podzolic soil
Sedgefield SH-sf Permian mudstone, lithic sandstone, shale, conglomerate, siltstone
yellow soloth, yellow solodic soils
Wappinguy SC-wp Triassic sandstone, shale, conglomerate, siltstone
siliceous sands, earthy sands, red solodic soils, brown solodic soils, yellow solodic soils, soloth
E. crebra (narrow-leaved red ironbark) community associated with: Awaba BP-aw Permian conglomerate, sandstone, shale brown podzolic soil, yellow earth, yellow
podzolic soil Bald Hill E-bh Tertiary basals shallow loams, euchrozem chocolate soil
intergrade Benjan SC-bj Permian shale, sandstone, conglomerate red solodic soils, yellow solodic soils,
brown solodic soils, non-calcic brown soils
Landscape Unit Lithology Soils Bogee SL-be Permian shale, conglomerate, sandstone red solodic soils, brown solodic soils,
yellow solodic soils Bulga SH-bu Triassic sandstone, conglomerate, shale yellow soloth, yellow solodic soils, brown
solodic soils Capertee YP-cp Permian shale, sandstone, conglomerate yellow podzolic soils, red podzolic
soils, brown podzolic soils, gleyed podzolic soils, yellow solodic soils
Glenbawn YP-gb Devonian and carboniferous shale, lithic sandstone, conglomerate
Jerrys Plains SH-lp Permian sandstone, mudstone, siltstone, conglomerate
soloth, yellow solodic soils, red solodic soils
Lethbridge RBE-lh Carboniferous sandstone, conglomerate, siltstone, shale
red-brown earths, red earths
yellow soloth, earthy sands, siliceous sands, yellow solodic soils
Merrilong BRE-ml Permian lithic sandstone, mudstone shallow loams, brown earths, brown soloth, yellow solodic soils
Moonabung SL-mb Carboniferous conglomerate, sandstone, shale, mudstone
red podzolic soil
Munghorn Plateau SS-mp Triassic sandstone, conglomerate, shale siliceous sands, yellow earth, yellow soloth Neath SC-nh Permian sandstone, conglomerate, shale shallow soils, siliceous sands, brown
solodic soils Pokolbin YP-pk Permian lithic sandstone, siltstone,
mudstone, shale, conglomerate red podzolic soils, yellow podzolic soils red soloth
Sandy Hollows SC-sy Permian sandstone, shale conglomerate yellow solodic soils, red solodic soils, siliceous sands, red earth, yellow solodic soils. brown solodic soils
Three Ways BP-tw Triassic sandstone, shale yellow podzolic soils, brown podzolic soils, brown earths, yellow earths, earthy sands
Wappinguy SL-wp Triassic sandstone, shale, conglomerate, siltstone
siliceous sands, earthy sands, red solodic soils, brown solodic soils, yellow solodic soils, soloth
Broad-leaved red ironbark community associated with: Collingwood RP-cg Permian sandstone, conglomerate, lithic
sandstone, tuff lithosols
lithosols, yellow soloths, red podzolic soils
Broad-leaved red ironbark and E. crebra (narrow-leaved red ironbark) community associated with: Barigan Creek YP-bc Permian sandstone, shale, conglomerate yellow podzolic soils, red podzolic soils Bayswater SL-bz Permian sandstone, shale, conglomerate red and yellow podzolic soils, yellow
solodic soils, yellow earths, brown earths Crowee YE-cr Jurassic shale, sandstone yellow earths, brown soloth, yellow soloth,
yellow solodic soil Dunville SC-dv Permian shale, sandstone, conglomerate brown solodic soil, yellow soloth, yellow
solodic soil Roxburgh YP-rx Permian lithic sandstone, conglomerate yellow podzolic soil lithosols, red solodic
soils, brown podzolic soils Broad-leaved red ironbark, Caley’s ironbark, Bayer’s ironbark, E. crebra (narrow-leaved red ironbark), red ironbark community associated with: Lees Pinch SL-lp Triassic sandstone, siltstone, conglomerate siliceous sands, yellow earths, sandy earths,
yellow podzolic soils, soloths Non-descript ironbark community associated with: Quarrabolong PS-qb Permian siltstone, sandstone, mudstone,
conglomerate brown soloth, yellow podzolic soil, yellow earths
Landscape Unit Lithology Soils Rothbury RP-ro Permian sandstone, siltstone, shale red podzolic soils, yellow podzolic soils,
brown soloths, yellow solodic soils
Table 5. Ironbark Species Occurrences Related to Landscape, Lithology and Soils. Wallerawang 1:100 000 map and report (King 1993).
Landscape Unit Lithology Soils Eucalyptus crebra (narrow-leaved red ironbark) community associated with: Rowans Hole-ro Conglomerate, sandstone, shale yellow podzolic soils, structured loams,
red podzolic soils Coco-co Devonian sandstone, schist, tuff, shale,
phyllite, quartzite lithosols, yellow podzolic soils, red podzolic soils, earthy sands
Canobla Gap-cg Permian conglomerate, sandstone, siltstone, shale
earthy sands, yellow podzolic soils, red podzolic soils, soloths
Broad-leaved red ironbark community associated with: Hassans Walls-hw Permian sandstone, claystone, shale,
conglomerate lithosols, yellow podzolic soils, brown podzolic soils
Hornsby-ho Triassic sandstone, tuff, agglomerate yellow podzolic soil, yellow-brown earths, red podzolic soil
Broad-leaved red ironbark, E. crebra (narrow-leaved red ironbark) community associated with: Glen Alice-ga Permian conglomerate, siltstone,
sandstone, shale yellow podzolic soils, red podzolic soils, soloths
Beyer’s ironbark community associated with: Gymea-gy Triassic sandstone, shale earthy sands, yellow earths, lithosols,
yellow podzolic soils, gleyed podzolic soils
5.3 The Temora Toposequence
Ironbark ridges have been studied in the Temora District of southern NSW (Johnston 1976). Their occurrence is related to lithology and soils (Johnston 1975b) which, in turn, have been related to landform and erosion hazard (Crouch 1975; Salmon 1993).
Ironbark communities occur on elevated areas of Silurian and Ordovician slates and shales. Where the sediments are overlain by more recent deposits, vegetation changes abruptly to a savannah woodland of grey box (Eucalyptus microcarpa) and Dwyer’s mallee gum (E. dwyeri) replaces ironbark on elevated areas of igneous or metamorphic origin.
Soils include lithosols (Um and red podzolic soils (Dr upper horizons and clay s parallel to the surface. T Henry 1977).
A Review of Literature on
Photograph 11. Bad sheet erosion and gullies on ironbark soils, Combaning.
1.21) (Northcote 1974), yellow and brown solonetzic soils (Db2.33), solodic soils (Dy3.42) 2.21). With the exception of the lithosols, soils are duplex, having coarse to medium-textured ubsoil. They are stony, of variable depth, and often contain coarse gravel and sand seams opsoils are difficult to wet and subsoils are usually highly dispersible (Johnston, Crouch &
Ironbark Ridges and Associated Lands Page 21
Ironbark ridges, although of low relief, are highly erodible. Under natural conditions, ground flora are sparse and, consequently, runoff yields are high. When cleared for agricultural production, significant erosion can occur. A major soil erosion problem in the Temora District occurs where runoff from ironbark ridges runs onto good quality arable land. The toposequence is dominated by lithosols on the ridges and hard setting solodic soils below these and then are followed by red earths and red-brown earths further down the slope.
5.3.1 Shallow S
These shallow gr tend to have quit development, apa horizon in some phyllites in a clay
5.3.1.1 Morphol
Shallow soils ma
1. High p 2. Shallo 3. Lack o 4. A unif 5. A mas 6. Often
5.3.1.2 Physical
3. The shal but respo
4. Dams of Stony an soils at d Hill as s
A Review of Literature o
Photograph 12. Badly sheet eroded waterway below an ironbark ridge, Ariah Park.
oils (Ucl.23, Ucl.43, Uml.43, Uml.33)
avelly soils are formed on tops of the slopes (ironbark ridge itself) on Silurian sediments. They e variable characteristics but, on the whole, are shallow soil (<60 cm deep) with little profile rt from the accumulation of organic matter in the top 5 cm of the profile and a bleached A2
instances. They consist principally of weathered, but not decomposed, quartz, slates and ey matrix and often have a seasonally hardsetting surface.
ogy of Shallow Soils
y be separated from other soil groups by the following features:
roportion of stony and gravelly material. w profile depth. f horizon development (A2 is occasionally present). orm coarse to medium texture throughout the profile. sive of fine powdery, single grain structure. a seasonally hardsetting surface.
and Chemical Properties of Shallow Soils
ater erosion occurs on these shallow soils which present a serious erosion hazard to the ing more valuable soils. Water sheeting and shallow gullying are widespread.
the shallow soils under ironbarks have hydrophobic topsoil caused by a coating of organic round the sand particles. This water repellence characteristic reduces infiltration in these soils. last few years, fungi have been attributed to playing a major role in the break down of organic tructural stability and hydrophobia.
low soils have low waterholding capacities and do not hold moisture for long during droughts nd quickly to light showers of rain (Salmon 1993).
ten do not hold water due to the sandy, gravelly soil and porous parent material underneath. d gravelly soil is very hard on cultivating implements. An indication of the coarseness of the ifferent locations is shown in the results of physical tests fr

Documents

Review of Literature on Ironbark Ridges and Associated Lands