Our Bushland Diary

Monday, January 31, 2011

in praise of Marri

If you check out the local bush reserves around Ellenbrook at the moment, you'll see Marri trees (Corymbia calophylla), their branches heavily laden with creamy blossoms. These stout bloodwoods have attractive dark brown trunks and glossy green foliage. The scientific name calophylla means beautiful leaf.

one of Ellenbrook's largest indigenous tree species
Marri are usually around 40 metres in height, a perfect size for parks and acreage. In the wild around Ellenbrook and further afield, marri can be found in groves of about a dozen trees, with a thick understorey of grasstrees and local shrubs. Marri give many things to many creatures; shelter for birds and marsupials, nectar snacks for insects and birds, crunchy fruit for possums, as well as cool shade for the resting bushwalker.

see the nest?
Imagine a grove of mature marri on a hot day. There will be lots of birds resting in the shade of the canopy – tiny birds such as the Yellow-rumped Thornbill, the Grey Fantail, the Brown Honeyeater and the Silvereye, and larger ones such as the Twenty-eight and Red-capped Parrot. Occasionally there may be birds rarely seen such as a sleepy Boobook Owl. Perhaps there is a little possum dozing in a hollow twenty metres up. The flowers are alive with buzzing and flitting things including bees and tiny butterflies, all attracted by the honey-sweet nectar.

a bonanza for birds and insects
 There may be couple of small skinks darting around as they hunt for moths and leafhoppers on the rough bark. The shrubs around the base of the tree benefit by the microclimate (shade and humidity) created by the tree.

marri trunk has distinctive bark and "kino" (red sap)
Even the ground around the tree is alive – the thin layer of natural mulch is home for beetles and earthworms, enriching the soil by breaking down the leaves. And you, standing underneath, breathing the air; cooled, filtered and re-oxygenated by Corymbia calophylla. Imagine how many life-forms are sustained by a single mature marri tree! I've heard them described as “apartments for wildlife” but it's more like an oasis resort with free food.

a lone marri on a sandy plain
Marri and other trees have been felled all around Perth to make way for blankets of roofs and hot bitumen. Scientists have recently discovered that cities become a “heat island” with temperatures above the surrounding countryside. Suburbs, including Ellenbrook, have the potential to become insufferable heat traps during our hot dry summers. We can help reverse the “heat island” effect by replacing some of the trees that were cleared.

let's keep the big trees alive in our housing developments!

[The above is an edited extract from an article published in local newspaper "Windows on Ellenbrook" in March 2008.  Photos and text by L. Dalgliesh aka Fat Bobbie]

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