Page:A primer of forestry, with illustrations of the principal forest trees of Western Australia.djvu/56

50 5.—MARRI (Eucalyptus calophylla).

A tree attaining a height of 90 to 100 feet, with a bole of 40 to 50 feet, and diameter of six to seven feet. The bark is persistent, and is of a hard, rough, and irregularly furrowed or broken appearance, giving a rugged aspect to the tree, it is also very often stained through the kino exuding from the tree running over it. The branches of the Marri are widely spreading and drooping, and for this reason it is one of our best shade trees, and among the most beautiful of our forest trees. The leaves of the Marri are broader than is usual with our timber Eucalypts, they are of a deep shining green, and the veins which cross the leaf from the midrib to the margin are straight and closely parallel. The flowers are large, and usually of a creamy-white, though sometimes pink, and hang downwards. The fruit, which forms after the flowers have withered, is frequently two inches in length and 1½ inches in diameter, and is roughly globular in shape, with a distinct neck at the top. The ovary is sunk some distance below this neck, thus leaving a bowl-shaped cavity below the rim. The seeds are large and black.

This tree yields a light-coloured strong wood. It is easily worked, and were it not for the presence of gum veins would be among the most valuable timber in Western Australia. Unfortunately, the gum or kino occurs in such quantities that it is difficult to find a tree free enough from gum to make it profitable to saw it up. It is used for all purposes where strength and elasticity are required. Timber hewers always take out the hickory shafts from their carts and replace them by marri shafts. Heavy poles used in the large whims which carry the great jarrah and karri logs to the mills are of marri. In the whim itself the fetchels, which are trusses to connect the pole with the axle bed, are also of marri. It makes a good axe and tool handle, and there would seem to be a future for it for all smaller turnery work.

It occurs throughout the jarrah belt, but like blackbutt is to be found generally on the better alluvial soils in the valleys between the laterite-capped ridges. Marri soil is generally considered from an agricultural point of view a degree better that jarrah soil, which from an agricultural standpoint is of little use.

The marri is generally known as red gum. As this name is commonly applied to a quite distinct species which grows in the Eastern States, it is better to use the name marri and avoid confusion.

While the presence of gum reduces the value of this timber, the gum itself has a special value for tanning purposes. From the earliest days of the Colony it has been used for tanning leather. Unfortunately, however, it imparts a red colour to the leather which is not appreciated by buyers overseas. Investigations have been carried out by the Forest Products Laboratory into the problem of the utilisation of this forest product for commercial purposes. It has been found that the tannin content is as high as 68 per cent.

In addition to the fact that the liquors obtained from the kino were a very red colour, it was found very difficult to get the kino into solution. After a great deal of research work on the part of the Leather Chemist attached to the laboratory, not only was the difficulty of getting the kino into solution overcome, but the objectionable red colour was reduced considerably. It is expected that in the near future commercial developments will take place in the direction of establishing tannin extract works in the State.

Marri has an advantage over all other tannin-bearing trees in that the product rich in tannin can be obtained without destroying the tree. The actual formation