Rainforest plants of Mount Glorious

The forests of Mount Glorious are a living history lesson. Walk from the car park at Maiala into the trees and you pass from open eucalypt forest into dense subtropical rainforest, with towering figs, palms, vines and ferns. Look closely and you will find clues to how the forest has changed: a lone giant gum surrounded by rainforest, stumps notched by timber-getters, and plants whose ancestors grew when dinosaurs walked the Earth. QPWS says more than 800 plant species grow in D'Aguilar National Park, some of them rare and threatened. This guide helps you recognise the most striking.

Why there is rainforest here

The D'Aguilar Range rises from the coastal plain north-west of Brisbane, and its highest parts catch moisture-laden air. On the summits, rainfall is about two-thirds greater than in the foothills. Combined with deep, rich basalt soils, particularly north of Mount Glorious, that extra rain supports moist subtropical rainforest.

Fire matters too. QPWS notes that pockets of subtropical rainforest are mostly restricted to southern slopes that have been protected from fire. Rainforest plants are generally fire-sensitive, so the boundary between rainforest and eucalypt forest often follows the lines that fire has drawn over centuries.

The forest types

A drive or walk through the park passes several distinct forest types:

• Dry eucalypt woodland on the shallow soils of the foothills, dominated by spotted gum and narrow-leaved ironbark, with patches of heath and grass trees.
• Tall wet eucalypt forest at mid altitudes, where grey gum, pink bloodwood and brush box dominate above a thick understorey of ferns, vines and shrubs.
• Subtropical rainforest on the highest, wettest parts of the range, with a closed canopy, strangler figs and a rich mix of species.
• Lowland rainforest in remnant pockets along some valley watercourses.

Plants to look for

Strangler figs

The giants of the Mount Glorious rainforest are strangler figs. Huge strangler figs, Ficus watkinsiana, can be seen emerging through the canopy on the range. Known as Watkins' fig, nipple fig or green-leaved Moreton Bay fig, this species can grow to about 60 metres tall and 2 metres in diameter, with smooth bark and sometimes buttresses.

Strangler figs are hemiepiphytes. A fig seed, dropped by a bird or bat high in a host tree, germinates in the canopy and sends roots down to the ground. Over decades the roots thicken and fuse into a lattice around the host, which may eventually die and rot away, leaving a hollow fig "trunk" of woven roots.

Watkins' fig grows in two separate populations, one in north-east Queensland and one from near Bundaberg to about Lismore, often on basalt soils. Its paired fruit are purplish-brown to black with a nipple-like tip, and they feed birds and flying foxes. Like all figs, it depends on a single species of tiny wasp for pollination, in a partnership known as obligate mutualism.

Sydney blue gum

On the Rainforest circuit, QPWS draws attention to an old Sydney blue gum, a magnificent survivor of the eucalypt forest that once dominated the area. Look for its smooth, pale trunk rising above the rainforest canopy. Eucalypts need light to regenerate, so a giant gum surrounded by rainforest is a sign that the forest around it has changed over the tree's long life.

Cycads

Lepidozamia peroffskyana is a palm-like cycad endemic to south-east Queensland and north-east New South Wales, growing on rainforest margins and in wet eucalypt forest, usually on steep slopes. It can grow to seven metres but usually reaches about four, with a crown of glossy, dark green fronds up to three metres long. Its cones are among the largest of any cycad: female cones can reach 90 centimetres and weigh up to 45 kilograms.

All parts of the plant are toxic to people and livestock, especially the seeds, which have bright red coats. Do not touch or eat them.

Hoop pine and red cedar

Hoop pine and red cedar were the trees that brought timber-getters to the range from the 1840s. QPWS notes that giant red cedar and hoop pine were felled to build houses that still stand in Brisbane today, and that stumps with notches cut for springboard platforms can still be seen in the park. Logging expanded in the 1870s, taking hoop pine, cedar, silky oak and black bean.

Native cypress pines

The Cypress Grove circuit at Maiala passes through a small grove of native cypress pines among large eucalypts and vines, a striking contrast with the rainforest nearby.

Palms, ferns and vines

The Rainforest circuit passes palms, ferns, climbing lianas and fungi. The cooler mountain climate is ideal for ferns and mosses. Woody vines climb towards the light, using host trees for support, and some reach the canopy before spreading out.

Rare and threatened plants

QPWS lists several plants of conservation significance in the park:

• Broad-leaved spotted gum (Corymbia henryi), which has a very limited distribution in South East Queensland but grows plentifully in the park.
• Queensland nut or bopple nut (Macadamia integrifolia), the edible macadamia, which grows in the north of the park.
• Maroochy nut or Gympie nut (Macadamia ternifolia), an inedible macadamia that grows on the slopes of Mount Nebo.
• Giant ironwood (Choricarpia subargentea).
• Corchorus cunninghamii, a delicate native shrub.

Both macadamia species are listed as vulnerable. They are a reminder that one of Australia's best-known food plants comes from forests like these.

Reading the rainforest

A few features help you recognise rainforest as you walk:

• A closed canopy that lets in little direct light.
• Buttress roots, flaring from the base of large trees.
• Vines and lianas, from thin wiry climbers to woody ropes.
• Epiphytes, plants that grow on other plants, such as ferns and orchids on branches.
• Leaf litter and fungi on a damp forest floor, where fallen material breaks down quickly.

Seasons in the forest

Rainforest changes subtly through the year. After summer rain, fungi appear on logs and the forest floor, and creeks run full. Fig trees fruit at different times, drawing birds and flying foxes. In the drier months of winter and early spring, tracks are usually firmer, leeches are fewer and walking is often more comfortable.