The great timber trees of the Wet Tropics

Skyrail Nature Diary: February 2011

Back in the early part of the 20th century, logging in the rainforests of Tropical North Queensland was widespread. The Barron Gorge (now the Barron Gorge National Park) was one of these sites, before its protection was recognised at a later stage.

On the Skyrail journey from Red Peak Station to Barron Falls Station, there is much evidence to suggest that the surrounding area was extensively logged, due to the proliferation of the Black Wattle (Acacia aulacocarpa: Mimosacea) - see image 1. Red Peak was the site of the main logging camp. All logging ceased in 1940 when Barron Gorge was declared Queensland's third national park.

The Wet Tropics has approximately 50 recognised species of timber trees. The most sought after timber trees were the Red Cedars (Toona australis: Meliaceae) and the Kauri Pine (Agathis australis) - see image 2. Red Cedars were generally not used by locals due to the need to treat the timber chemically to protect it from borers, particularly the caterpillars of the Tip Moth. Kauris are considered to be borer proof.

Several species of laurels were sought after as cabinet timber. These include the Yellow Walnut (Beilschmiedia bancroftii: Lauraceae), Mackinnon's Walnut (Cryptocarya mackinnoniana:Lauraceae), Pepperwood (Cinnamomum laubatii: Lauraceae) and the Northern Rose Walnut (Endiandra hypotephra: Lauraceae). All laurels have tiny flowers, while most have toxic fruits. The Yellow Walnut has unusually large fruits shaped like balls, with two pointed ends and distinctively brown flowers. They were eaten by the Djabugandjii people (traditional aboriginal tribe) after extensive leaching in running water.

Silky Oaks (Proteaceae) have dense, heavy timber and are often used for doors and other structures requiring strength and durability. The most commonly collected species were Briar Silky Oak (Musgravea heterophylla: Proteaceae) - see image 3, Black Oak (Stenocarpus reticulatus: Proteaceae), Rose Silky Oak (Placospermum coriaceum: Proteaceae) and the White Oak (Grevillea baileyana: Proteaceae). All have grevillea-like flowers that are either reddish or cream. The fruits are generally small woody capsules filled with papery seeds. Most Silky Oaks prefer well drained terrain.

Relatives of the citrus trees from the genus Flindersia have long been popular timber trees. Several have strong smelling timber, one of which includes Hickory Ash's (Flindersia ifflaiana: Rutaceae) timber which smells of curry - see image 4. The flowers of these magnificent trees have no discernible scent, are usually white and occur on the top of the canopy in large bundles. The exception is the Maple Silkwood (Flindersia pimenteliana: Rutaceae) which has dark, red flowers. All have woody, gherkin-shaped fruits that split into five fingers and release numerous papery seeds into the wind. All have compound leaves that are quite distinct. The Queensland Silver Ash (Flindersia bourjotiana: Rutaceae) has the largest leaflets of them all and have an unusual soft corduroy texture. All are beautiful trees growing up to more than 30 metres. The remaining species found in this area include the Silver Silkwood (Flindersia acuminata: Rutaceae), the Northern Silver Ash (Flindersia schottiana: Rutaceae) and the Queensland Maple (Flindersia brayleyana: Rutaceae).