Category: Rainforest Trees

I have chosen Davidson’s Plum (Davidsonia pruriens) as the July Rainforest Tree of the Month because my attention was drawn to this tree by the abundant litter of large, purple fallen fruit on the ground beneath a tree near the Paluma Environmental Education Centre’s fire pit.  Investigating, I saw that the tree was well laden with bunches of fruit, some ripe and ready to fall while small green fruits were also strewn along the branches.  It was early in June when I saw the fruit but fruiting can occur at any time of year.

Although it is a rainforest tree, Davidson’s Plum is not endemic to Paluma.  It grows to about 18 metres high and is found from sea level to altitudes of up to 1095 metres from near the Big Table-land near Cooktown to Cardwell.  There are three species of this genus endemic to Australia, one occurring in Tropical North Queensland.

The name Davidsonia, named after a pioneer sugar-cane grower, J E Davidson is ironic given that so much of the lower level rainforest where this tree occurs, has been lost to cane-fields.  Pruriens, means itching or stinging and applies to Davidson’s Plum because there are irritant hairs on leaves and young fruit.

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The large, hairy compound leaves of this tree are distinctive with deeply serrated edges to the leaflets and little leaf-like protrusions between the leaflets.  Both sides of the leaf are covered with fine hairs.

Flowering can occur at any time.  Flowers are tiny, with no petals but have four or five green or pink sepals.  The grow in panicles (bunches) from leaf axils or are cauliflorous (along the trunk) or ramiflorous (on the branches).

The fruit is a drupe, (fleshy), with two seeds   The developing green fruit is well covered in fine hairs which can cause considerable irritation and itching.  Ripe fruit is roughly oval to round, about five centimetres long, and is dark purple to almost black with a fine powdery, whitish bloom on the surface.   The flesh is dark pink.  Of the two seeds, usually only one is fertile.  The fruit is highly acidic, too tart to eat raw, although it was eaten by Aboriginal people, but It can be made into a delicious wine, jam or jelly. Cassowaries, Sulphur-crested Cockatoos and Double-eyed Fig-parrots eat the fruit.

A good example of the Davidson’s Plum can be seen at the forest edge behind Paluma Environmental Education Centre, near the fire pit.

Colwyn Campbell

A recent discussion with friends about a very large tree in their garden which was to have a limb lopped off, has prompted me to feature the species Flindersia as Rainforest Tree of the Month.  The limb of the tree in question hung dangerously over the roof of their house.   My friends understood this tree to be Australian Teak, Flindersia australis, but I questioned this as it did not quite match the characteristics of Flindersia australis.

The seed capsule collected from my friends’ tree, was still green and had a bumpy surface rather than the characteristic spiny surfaced, five valved seed capsules of the Flindersia australis.   Nor did the leaflets of the compound leaves, being slightly curved, match the elliptic shape of those of Flindersia australis.  The distribution of this tree is in rainforest from near Proserpine to northern NSW, at altitudes up to 750 metres.   So, I feel that more likely candidates for my friends’ tree would be Flindersia acuminata, Flindersia brayleana, Flindersia bourjotiana or Flindersia pimenteliana, all of which are endemic to Paluma.

There are seventeen species of Flindersia world-wide; growing in New Caledonia, New Guinea, Malesia and Australia. Fifteen species are endemic to Australia.  The species is named after Matthew Flinders (1774-1814), the renowned navigator and cartographer who led the voyage of ‘The Investigator’ on which the British botanist, Robert Brown, collected many Australian plants.  Flindersias are members of the Rutaceae family.

Flindersia australis, also known as Teak, Australian Teak and Crows Ash,can grow to a height of 40 metres on rich, volcanic rainforest soil.  It is somewhat smaller elsewhere.  Sprays of tiny white flowers appear from August to February with the spiny seed capsules forming from March to January. Unlike most other Flindersia species, these segments do not separate into individual portions.  The 35-50mm seeds are flattish and winged at the apex.  The timber is in demand for general building, flooring and fencing.  It has a high oil content and is readily flammable.

Flindersia pimenteliana is also known as Maple Silkwood, Rose Silkwood and Mountain Silkwood.  This majestic tree grows to 30 metres high and may be buttressed.  It occurs from Mt Finnegan near Cooktown to Paluma and also is found in New Guinea.  The leaves, like other Flindersias, are compound but the leaflets taper to a narrow point.  The flowers are similar in size to the inflorescence of the other Flindersia species but are red to purple.  They appear from November to March and are difficult to see high in the canopy.  The fruiting capsule, 55 – 115 mm long, is green to brown with five spiny valves.  These split and release about 20 flat, winged seeds about 45-50mm long, from July to December.

Sulphur-crested cockatoos eat the seeds.

The timber of this tree was once used to make barrels and very decorative cabinet timber.  Although young plants grow readily, they are not an economic tree to grow in plantations due to their spreading structure.   Leaf material has been found to be active against some tumours.

There are several fine examples of Flindersia pimenteliana to be seen around the village. The easiest to find is in the stand of trees in the area between the tree ferns and the road cutting opposite the Rainforest Inn, (the kitchen end near the entrance to the motel units).   Some still attached, green seed capsules hang just above eye level.  Other trees can be seen at the end of Smith Crescent, at Number 20 and at the fence-line between Numbers 15 and 17 Mount Spec Road.

Flindersia schottiana is another tree which could possibly be found in the Paluma area as its distribution range is from Cape York to Port Macquarie at altitudes up to 1300 metres.  This tree is also known as Silver Ash, Bumpy Ash, Floppy-leaf Ash and Cudgerie. A majestic tree, growing to 45 metres, it is rarely buttressed.    The trunk features large bumps where old branches have been detached, hence its common name, Bumpy Ash.  The tree has compound leaves with 7 to 9 leaflets, 50 to 260mm long.  The upper-side of the leaves is mildly hairy with dense, fine hairs on the under-side.  The tiny white or cream flowers are fragrant, appearing from August to December and in May. The five-valved fruit capsules are spiny, 80-130mm and release about 30 flat winged seeds from December to April.  Flindersia schottiana is a pioneer tree, often found in regrowth areas and rainforest margins.

Flindersia acuminata, also known as Silver Maple, Silver Silkwood, White Silkwood and Ice-wood, occurs at altitudes up to 1200 metres in rainforests between the Windsor Tableland and Paluma.  The tree can grow to a height of 40 metres and may be buttressed.  The elliptic leaflets of the compound leaves are from 50 to 150 mm long, slightly curved, and tapering to a point.  Fragrant white or cream flowers grow in terminal or axillary panicles from November to January.  They are tiny, with five petals and are only about 3 mm in size. The fruit capsules, appearing from June to March are green to brown, 90 to 150 mm long and have five spiny valves which split to release flat, papery winged seeds, 65 to 80 mm.

Flindersia bourjotiana, also known as Queensland Silver Ash, Silver Ash and White Ash. The distribution of this tree is in rainforests from McIvor River near Cooktown to the Paluma Range at altitudes up to 1200 metres.  The tree grows to about 35 metres and may be buttressed.  The leaves are compound, with 3 to 9 elliptic leaflets, from 50 to 190 mm long.  The underside of leaves can be slightly hairy.   The tiny, (5-9mm), fragrant flowers can be white, cream or green and grow in terminal or axillary panicles, or sprays. Flowering occurs between April and January.  Fruit capsules can be up to 150 mm long with five spiny valves which split to release several flat, winged seeds, 30-70 mm long.  Sulphur-crested cockatoos and giant white-tailed rats eat the seeds.

Flindersia brayleana, is also known as Queensland Maple, Maple Silkwood and Red Beech. A tree growing to 35 metres, its distribution is from the Windsor Table-land to Mount Halifax near Townsville, at altitudes up to 1150 metres.  The compound leaves have slightly curved leaflets, tending toward an ovate/elliptic shape and ranging from 60 to 210 mm in length.  Tiny fragrant white flowers with five petals 3mm in size grow in terminal or axillary panicles from November to January.  They are difficult to see high in the canopy.  The fruit capsules, are 60 to 100 mm long, and have bumps rather than spines on the surface.  They split into five valves, or segments, and release several winged seeds.  Flindersia  brayleana was once a common tree in rich, red, volcanic soils on the Table-land and on Mount Spec however, high demand for its exceptionally beautiful pink timber has caused it to become scarce. During World War 2, the timber was sought for use in aircraft production, such as in the manufacture of propellers and for ply-wood used in the Mosquito bomber aircraft.  The timber was also used in rifle stocks and for beautiful decorated stocks in sporting rifles and shotguns. Boxes, barrels and window frames were also made from this timber.  The timber can cause dermatitis.

Text and Photos by Colwyn Campbell

Eucalyptus grandis, known as the rose gum, is a tall tree with a smooth pale trunk and a skirt of rough bark around the base extending up several metres. It occurs in wet sclerophyll forests from the Daintree to around Newcastle and favours coasts and lower slopes in areas of rich soil and high rainfall. Stands dominated by the Rose Gum are frequently found adjacent to rainforests. In Paluma the best examples can be found near the Taravale turnoff along the Hidden Valley Road. My family call this area the Valley of the Giants and it’s an apt name. There are also several lovely specimens along Benham’s Road from the dam spillway onward. The rose gum does not usually germinate or mature in established rainforest habitat, but it’s not unusual to come across one that is a remnant from a wet sclerophyll forest that has been encroached by rainforest during periods of high rainfall and low bushfire frequency. There is a huge but now half broken specimen like this on the way to Birthday Creek Falls¹.

There is a lot of interest worldwide in “big trees” and lots of competition for bragging rights for various categories. More that one website dedicates itself to this obsession, including the National Register of Big Trees, which lists the biggest trees of each Australian species. The rose gum is one of the largest trees in Australia. It commonly exceeds 50m in height, and the current record for this species is 86m. It is currently considered to be the tallest species in Queensland with a tree in the Conondale National Park called Big Bob measured at 72m in height. By comparison, the tallest tree species in Australia is the mountain ash (Eucalyptus regnans) with an individual called Centurion (>100m) classed as the tallest tree in Australia and the tallest hardwood tree in the world.

Eucalyptus grandis is very fast growing under ideal conditions and can reach up to 7m in its first year. It is a popular plantation tree inside and outside Australia for its timber and pulp. Timber applications include general construction hard wood, flooring, furniture. The leaves of the rose gum are eaten by koalas, which can also be found occasionally around the Taravale/Mt Zero area.

Text and photos by Jamie Oliver

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¹ look for a clearing and locked gate on the left about halfway to Birthday Creek Falls and go down this old logging road for about 200m. The tree is on the left.

This tree is also known as the Northern Silky Oak or Bull Oak.

Two seasons ago, after the rainy season, many patches of the rainforest floor were covered in what appeared to be leafy green butterflies. Close inspection showed that they were actually the seedlings of the northern Silky Oak (Cardwellia sublimis). The seeds of this species are flat and ovate, and when they germinate the two halves of the seed (cotyledons) split apart to become green pseudo-leaves, with the stem of the seedling in the middle. After a month or so the first true leaves develop and the butterfly shape is lost.

Despite the fact that these were a common sight, none of us managed to capture the full splendour of this display on a camera so the picture of a solitary seedling here does not do justice to what we saw.  The display has  not been repeated in subsequent years. Perhaps next year?

Sublimis derives from Latin, meaning tall and lofty and Cardwellia sublimis is indeed that, growing to a tall and shapely 35 metres.  It is the only species in its genus and is endemic only from the Big Table-land near Cooktown to the Paluma Range, growing at altitudes up to 1300 metres.  The tree was named by Ferdinand von Mueller in honour of Edward Cardwell, Secretary of State for the Colonies from 1864 to 1866.  The type specimen was collected by John Dallachy in Rockingham Bay.  Its name in the local Dyirbal language was ‘jungan’.

The compound leaves have 6 to 20 leaflets arranged in pairs on short stalks. They are about 20 cm long.  The upper surface of the leaf is glossy dark green and glabrous (hairless), while the underside is covered in minute rusty coloured hairs.

The fragrant white or cream flowers grow in terminal racemes or spikes, crowning the tree spectacularly from October to December. Then, in January, standing proud on long stems above the tree canopy, the large oval seedcases are silhouetted against the sky.  When ready, these capsules crash to the ground or (with a startling bang) onto a house roof, opening to release 6 to 12 winged, flat seeds. The empty seed capsules, or follicles, split along one side only.  They are brown and woody and lie like miniature cobblestones on a bumpy pavement but they quickly decompose back into the soil.  Seeds of Cardwellia sublimis are eaten by Sulphur-crested Cockatoos, Bush Rats and Giant White-tailed Rats.

The dark, oak-like timber of this tree is highly regarded and sought after for furniture and cabinet making. It once made up 15% of all timber production in the area.

Text and sketch by Colwyn Campbell;
Photos by Colwyn Campbell and Jamie Oliver

Also known as Ivory Curl Flower and Spotted Silky Oak

Buckinghamia celsissima belongs to the plant family Proteaceae and is endemic to the wet tropical rainforests of North Queensland from near Cooktown to the Paluma Range.  The species was described by Ferdinand von Mueller in honour of his friend Richard Granville, 3^rd Duke of Buckingham from a collection made by John Dallachy in 1865.

It is a handsome tree, growing to about 30 metres and may be buttressed.  Foliage is dense with glossy, dark green simple leaves, 8 to 16 cm long by 3 to 7 cm wide. The leaf underside is whitish.  Juvenile leaves can have one or two lobes and foliage may be flushed with red during periods of new growth.

Flowering shows the Buckinghamia celsisima in its full glory as masses of fragrant white to cream drooping spikes cover the tree.  (A magnificent specimen is located in the Trees of Memory grove at the foot of the Village Green).  The flowers, up to 20 cm long, grow in terminal racemes and are visited from dawn to dusk by bees and birds. The flowering period is usually between January and May.

The green to brown fruit is a woody follicle or capsule, 15 -30 mm by 12 -18 mm, which splits open along one side to release three to six flat, narrowly winged seeds. Crimson Rosellas feast on the seeds.

The tree is popular with gardeners as propagation from cuttings is usually successful though slow but the seed is easy to germinate and produces plants which will flower in three years.  The tree is also grown as an attractive street tree as it seldom reaches the same height as in its natural environment and is also amenable to pruning.

Footnote:  The Village Green specimen, so glorious in mid-February, has suffered a battering from the heavy rain over the weekend of 22/23 Feb, its blooms now rather bedraggled but still beauriful..

Text and images by Colwyn Campbell

Beginning around the middle of last month (May) some of the tracks around the village had patches of colourful but strangely shaped fruit on the ground. These flattened orange to yellow fruit often have a single seed stuck in the middle. While most rainforest trees are difficult to distinguish based solely on the trunk or leaves, their fruit and flowers can often be distinctive and render them easily identified. Such is the case with McIntyre’s Boxwood (Xanthophyllum octandrum). The best example I have found (although it may now be finished fruiting) is on the H-track just uphill (towards Lennox Crescent) from the old mining test pit and creek lookout. Two mature trees stand near the track (on the left as you face uphill).

MacIntyre’s Boxwood is endemic (i.e restricted to) Queensland, occurring in rainforests from Cape York to the central Qld coast¹. Flowering occurs in early summer but the flowers are fairly inconspicuous. The fruit are round, marble-sized and green to pale yellow. When ripe they split open (dehisce) while still attached to the tree to reveal a dark seed attached to the now flattened internal yellow flesh. At this stage the fruit are fairly conspicuous on the tree, and even more so on the dark leaf litter of the forest floor once they have fallen.

The fruit is eaten by Cassowaries. The trees are slow growing and large specimens are likely to be very old. The timber has been used commercially and was commonly used to make wooden rulers.

¹trin.org.au

Text and photos by Jamie Oliver

While citrus trees around Paluma are full of fruit at present, providing sustenance more to the Cockatoos than human residents, there is also a native rainforest tree/shrub that is currently laden with large round fruit that are beginning to turn yellow or bright orange. From a distance the fruit looks very much like an orange. This is the Native Gardenia or Yellow Mangosteen (Atractocarpus fitzalanii – previously known as Randia fitzalanii¹)

Native Gardenia is a native under-story tree in eastern Queensland rainforests. The star-shaped white flowers appear in spring and (unsurprisingly) look at bit like simple gardenia flowers (they share the same family) and have a pleasant perfume.

The fruit is edible and is reported to be good bush tucker². It can be eaten raw or used in salads, tarts, cakes or other deserts. In fact one author reports that it is one of the few plants that was consumed for is aphrodisiac properties!¹ Cassowaries also eat the fruit, but the literature is silent on whether these birds also use it to enhance their reproductive drive. Perhaps you should exercise caution if you see a large male Cassowary with a gleam in its eye when you visit our local grove!

The Native Gardenia is fairly commonly sold in nurseries for its lush foliage and perfumed flowers. The fruit can be quite sweet in some trees but this is quite variable. I confess I have not sampled the fruit but Wilfred had a quick taste of the one at Jourama Falls and found it unremarkable.

Text and photos by Jamie Oliver

¹ trin.org.au
² tuckerbush.com.au