Kauaʻi record · kba_plant_casuarina_glauca
Swamp She-oak
Casuarina glauca
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About Swamp She-oak
Swamp She-oak (Casuarina glauca) is an introduced tree treated as naturalized on Kauaʻi by Bishop Museum’s 2025 checklist and the 2026 Smithsonian checklist. Current extent is unassessed. An eastern Australian tree associated naturally with coastal rivers, estuaries, swamps, and brackish or saline wet ground. It forms nitrogen-fixing root nodules with Frankia and can form stands through both seed and root suckers. Naturalized on Kauaʻi in the Bishop Museum 2025 checklist (Status=nat; K=K), with Smithsonian 2026 Kauaʻi corroboration; public occurrence is island-level only. This evidence does not quantify current abundance or ecological effects.
Kauaʻi evidence
Taxonomic identity, tree form, diagnostic morphology and island occurrence use the linked reviewed sources. Historical planting, cultivation, naturalization and invasive status are separate. Generated imagery is not occurrence evidence. The 1918–1959 Kauaʻi reforestation working register records 108,863 plants under Casuarina glauca across 23 entries dated 1928–1958. These are recorded planting quantities, not counts of surviving trees, and they do not by themselves establish current persistence, naturalization, or ecological impact. Source: Kauaʻi Reforestation Plantings 1918–1959 working register (user-supplied; reconciled 6 October 2026).
Names and classification
- Scientific name
- Casuarina glauca
- Common names
- Swamp She-oak · Longleaf ironwood · Saltmarsh ironwood
- Other names
- Casuarina glauca · Swamp she-oak · Longleaf ironwood · Saltmarsh ironwood · Casuarina obtusa Miq.
- Record type
- Species
Kauaʻi occurrence and status
- Kauaʻi occurrence
- Recorded on Kauaʻi
- Origin
- Introduced
- Conservation status
- Not yet assessed
- Evidence date
- 2026-10-06
- Evidence limits
- Current island-wide abundance, occupied habitat, reproductive distribution, population trend, and ecological effects on Kauaʻi remain unassessed.
Habitat and ecology
- Habitats
- Not yet assessed
- Food and resource needs
- Not yet assessed
- Reproduction
- Male and female structures are normally borne on separate trees. Wind-carried pollen permits fertilization of female heads, whose woody cones release small winged nuts; the species can also spread vegetatively by root suckers. Kauaʻi-specific sex ratios, cone production, dispersal, suckering, and recruitment are unmeasured.
- Shelter
- Not yet assessed
- Growth form
- Tree
Threats and conservation
- Monitoring
- Not yet assessed
- Data gaps
- Current population extent and trajectory · Additional species-specific ecological and conservation sources
Process and seasonal context
- Seasonal timing
- Not yet assessed
- Seasonal description
- Swamp She-oak (Casuarina glauca) is an introduced tree treated as naturalized on Kauaʻi by Bishop Museum’s 2025 checklist and the 2026 Smithsonian checklist. Current extent is unassessed. An eastern Australian tree associated naturally with coastal rivers, estuaries, swamps, and brackish or saline wet ground. It forms nitrogen-fixing root nodules with Frankia and can form stands through both seed and root suckers. Naturalized on Kauaʻi in the Bishop Museum 2025 checklist (Status=nat; K=K), with Smithsonian 2026 Kauaʻi corroboration; public occurrence is island-level only. This evidence does not quantify current abundance or ecological effects.
Sources and further reading
- https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:52191-3
- https://naturalhistory2.si.edu/botany/hawaiianflora/speciesdescr.cfm?genus=Casuarina&species=glauca
- https://apps.lucidcentral.org/plants_se_nsw/pdf/entities/casuarina_glauca.pdf
- https://www.fs.usda.gov/nsl/Wpsm/Casuarina.pdf
- https://www.plantsofhawaii.org/search/Casuarina%20glauca
- https://hbs.bishopmuseum.org/publications/pdf/tr75.pdf
- https://editedimages.s3.us-east-1.amazonaws.com/Imadaetal.2025Hawaiianvascularplants.xlsx
- https://doi.org/10.5479/si.32124043