This species has a wide distribution across the southern part of Western Australia, and is mostly found within 150 km of the south coast [1,2]. Its most western occurrences are in the vicinity of the Rocky Gully-Arthur River area and it extends east to as far as Israelite Bay and Mt Ragged. Across its natural distribution E. occidentalis may be a tree up to 25 m tall or a large mallee depending on the severity of the site. The main occurrences of E. occidentalis are in proximity to rivers, creeks and salt lakes, but large stands also occur on undulating hills and near granite rock outcrops.
Flowering and seeds
Eucalyptus occidentalis flowers from April to August [1,3]. This species is one of the most precocious, early flowering eucalypts, being known to flower within the first year of growth. Seed capsules persist on trees until at least the following spring. There are about 160 viable seeds per gram; seeds start to germinate in about 5 days if grown at 25°C with no pretreatment required .
Cultivation and uses
This species can be grown on waterlogged sites in discharge areas, including areas affected by moderate to high levels of salinity . It has been successfully cultivated in dryland parts of southern Australia in areas that receive 350 mm rainfall per annum, that are subject to frosts and periodic drought. This species produces durable wood that has potential as sawn timber and provenance trials for this purpose have generated interest in seed from stands north of Esperance and from near Ravensthorpe . In a number of overseas countries E. occidentalis has shown potential for a range of purposes that include, fuelwood, poles and posts, sawn building timbers, boxes, short fibre pulp and charcoal, but it is mostly grown for firewood, shade, windbreaks and catchment afforestation [1,4]. There is considerable potential to cultivate this species well beyond its natural range .
Mean annual rainfall: 300-900 mm
Rainfall distribution pattern: uniform or winter
Mean annual temperature: 12-18 °C
Mean max. temperature of the hottest month: 26-31 °C
Mean min. temperature of the coldest month: 4-7 °C
Frosts (approx. no. per year): frost free or more or less frost free or up to 20
Frost intensity: light to moderate (0 to -5°C)
Altitude: 0-300 metres
Tolerance of extremes in climate
Drought: known to be tolerant of protracted droughts
Fire: regenerates foliage after damaging fire
Frost: tolerates frosts in the 0° to -5°C range
Wind: tolerates salt-laden coastal winds
Texture: clay loam, heavy clay (greater than 50% clay), light to medium clay (35-50% clay), loam, sandy loam, sandy clay loam or sand
Soil pH reaction: neutral (6.5-7.5) or alkaline (greater than 7.5)
Soil depth: moderate to deep (30-100 cm or greater)
Drainage: well-drained, poorly to imperfectly drained or seasonally waterlogged
Salinity: highly saline, slightly to moderately saline or non-saline
Tolerance of adverse soils
Extremes in pH: alkalinity
Extremes in texture: clayey
Salinity: extremely high (> 16 dS m-1), high (9-16 dS m-1), moderate (-8 dS m-1) or slight (2-4 dS m-1)
Soil waterlogging tolerance: drainage may be sluggish at times
Biological traits under cultivation
Habit: evergreen tree 15-30 m tall, usually produces a clear trunk or sometimes with multiple stems from or near ground level
Longevity: moderate to long lived (>15 years)
Growth rate: fast or moderate
Coppicing ability: vigorous, responds to pruning, pollarding: lignotuberous
Root system: moderate to deep or shallow and spreading
Erosion control potential: excellent for clayey sites
Windbreak potential: tolerates salty coastal winds
Wood density: mod. to high (greater than 600 kg/cubic metre)
Carbon sequestration potential: moderate to high
Potential farm use: good for fence posts, shelterbelt or shade for stock
Specialty products: flowers produce nectar for honey production, high tannin content in bark
Urban use: good as an ornamental or amenity plant
Wildlife value: flowers are especially attractive to birds
Wood products: pulpwood (wood chips for paper pulp), boxes, crates, heavy construction, high quality fuelwood, industrial charcoal, light construction, poles (building, transmission, piling), posts (including fencing)
Potentially undesirable attributes
Growth habit: shallow roots may outcompete adjacent plants
Susceptibility to disease or predation: foliage highly susceptible to insect predation or pathogenic leaf diseases, susceptible to stem girdling by parrots
Weediness: high potential based on its biology
 Boland DJ, Brooker MIH, Chippendale GM, Hall N, Hyland BPM, Johnson RD, Kleinig DA, McDonald MW, Turner JD (2006) Forest Trees of Australia. CSIRO Publishing, Collingwood.
 Slee AV, Connors J, Brooker MIH, Duffy SM, West JG (2006) EUCLID Eucalypts of Australia. Third Edition CD ROM Centre for Plant Biodiversity Research. CSIRO Publishing, Melbourne.
 Gunn BV (2001) Australian Tree Seed Centre Operations Manual. Internal Publication, CSIRO Australian Tree Seed Centre, ACT. [Online at http://www.ensisjv.com/Portals/0/atsc-opmanualcomplete.pdf Accessed March 2008]
 Marcar NE, Crawford DF (2004) Trees for Saline Landscapes. RIRDC Publication Number 03/108, Canberra.
 Harwood CE, Bird R, Butcher T, Bush D, Jackson T, Johnson I, Stackpole D and Underdown M (2005) Australian Low Rainfall Tree Improvement Group (ALRTIG) Update of hardwood breeding strategies, A report for the RIRDC/Land & Water Australia/FWPRDC/MDBC Joint Venture Agroforestry Program RIRDC Publication No 05/023 RIRDC Project No. CSF-62A. Available from the RIRDIC website at http://www.rirdc.gov.au/reports/AFT/05-023.pdf
 Jovanovic T, Booth TH (2002) Improved species climatic profiles A report for the RIRDC/L&W Australia/FWPRDC/ MDBC Joint Venture Agroforestry Program. RIRDC Publication No 02/095, Canberra.
Victorian Department of Primary Industry: http://www.dpi.vic.gov.au/ [Search site as several documents may relate to this species.]
Western Australian Department of Agriculture and Food: http://www.agric.wa.gov.au [Search site as several documents may relate to this species, eg, http://www.agric.wa.gov.au/content/lwe/vegt/trees/fs02700.pdf; http://www.agric.wa.gov.au/content/lwe/salin/smeas/plant_salt_tolerance.htm]