Tuesday, April 26, 2011

Ghosts of Australia - The Australian Pine

That which we call a pine by any other name might not be a pine.
Growing along the coast of South Florida is an invasive tree known locally as an Australian Pine (Casuarina equisetifolia). It is in fact found in Australia as well as other locations in that region. It is in fact not a pine. Despite the peaceful sound the wind makes as it passes through the tree’s pine needle-like branchlets, it is a tree we need to do without here in Florida. Eradication programs exist but it is a resilient tree and has numerous fans.
My wife and I went for a short walk to take photos of a living Australian Pine. It was a blistering, hot March day and when we reached the shade of the 50-foot tall tree she said with sincerity, “Excellent. Shade.” It’s no wonder it has been hard to convince people that these “pines” have to go.
The evergreen was introduced to the sunshine state as a shade tree and a wind break. Its tolerance to high salinity gives it an advantage in old beach communities as well as newly formed beaches. It grows fast and as it does, drops needle-like branchlets that cover the ground. It renders the soil toxic to dune grasses, sea grapes and just about every other native species.
The other big issue is beach erosion. C.equisetifolia is the tallest of three invasive Australian Pines and can grow up to one hundred feet. Surprisingly is has a very shallow root system. The tree is easily toppled during storms and the massive trunks create unnatural breakers on the beach, leading to severe beach erosion.
Management of the three species is difficult. Cutting the main trunk can lead to root suckers – new trunks that grow from the roots. Herbicides are used with caution and fire can be used with care in fire tolerant plant communities. While the beauty of this tree can be appreciated, the destruction it causes must be recognized as well.
In the photo, a lifeless Australian Pine skeleton has succumbed to the sea – a ghost of Australia on the Florida coast.

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