Question 1

What is Casuarina equisetifolia used for in Ayurveda?

Accepted Answer

In Sri Lankan Ayurvedic practice, the bark and branchlets of Casuarina equisetifolia are used in decoctions traditionally associated with digestive complaints, diarrhoea, and skin conditions. The bark is notably astringent due to its high tannin content. These applications are recorded in Sri Lanka's official catalog of Ayurvedic medicinal plants, though clinical evidence for specific uses is still emerging.

Question 2

What is the Sinhala name for Casuarina equisetifolia?

Accepted Answer

The tree is commonly called Thora or Ruk-Athana in Sinhala. It is also widely known in English as the horsetail tree or Australian pine, though it is not related to true pines. Different regions of Sri Lanka may use slightly varying local names.

Question 3

Where does Casuarina equisetifolia grow in Sri Lanka?

Accepted Answer

The species is most common along the north-western and northern coastlines, particularly around Kalpitiya, Mannar, and Puttalam, where it grows in windbreak rows on sandy beaches and dune systems. It also appears on the edges of dry-zone irrigation tanks and scrub forests. It is rarely found in wet-zone rainforests or high-altitude areas.

Question 4

Is Casuarina equisetifolia an invasive species?

Accepted Answer

The tree is considered potentially invasive in some coastal ecosystems because dense stands create thick litter that suppresses native ground vegetation. It was widely planted for coastal stabilisation and windbreaks in the twentieth century, which contributed to its spread beyond natural ranges. Conservation managers in Sri Lanka now monitor its impact in sensitive habitats.

Question 5

What are the ecological benefits of Casuarina equisetifolia?

Accepted Answer

The tree fixes atmospheric nitrogen through symbiotic root bacteria, enriching poor sandy soils and enabling other plants to colonise after it. Its deep taproot and canopy reduce coastal soil erosion and provide shelter from strong winds. These qualities made it a popular choice for government afforestation and shoreline protection programmes.

Question 6

How can I identify Casuarina equisetifolia in the field?

Accepted Answer

Look for a tall, slender tree with thin grey-green branchlets that resemble pine needles — these are actually photosynthetic stems, not true leaves. The real leaves are tiny scale-like whorls on the branchlets. Small woody cone-like fruits about 1–2 cm across are distinctive and appear after flowering.

Question 7

Is Casuarina equisetifolia wood used commercially in Sri Lanka?

Accepted Answer

The timber is hard and dense, which historically earned it the common name ironwood in some regions. It has been used for fuel, poles, and rough construction in rural areas. Commercial timber use is limited compared to plantation species, but firewood from Casuarina is valued for its high calorific output.