ONE of Redland city's major tourist attractions, King Island, off Wellington Point, is shrinking and the sand island is drifting north.
Environmental watchdog SEQ Catchments's manager for Redlands Joel Bolzenius said the island had shrunk to an area of 0.3ha (0.7 acres) over the past century.
Mr Bolzenius said although exact measurements from the early 20th century were unavailable, historical photographs and aerial shots dating back to the 1900s showed significant shrinkage.
"It is a coral island but is like all sand islands, such as North Stradbroke, Moreton, Bribie and Fraser, and is constantly moving with the prevailing winds from the south-east," Mr Bolzenius said.
"Like all sand islands, it will get smaller and erode away on one side as the older vegetation collapses under the prevailing south-east winds and sand accumulates on the north-westerly side of the island.
"Bird Island, off North Stradbroke Island, was covered in Casuarina trees which are no longer there and now the island disappears completely under water at high tide."
Mr Bolzenius said although it would be many years before King Island would disappear under the water, he warned that cutting down its mangroves would speed up the process.
Long-time Wellington Point resident Bill Parker, 75, said the island's shrinkage was alarming and noticeable and the number of mangrove trees lining the beach had halved since he was an eight-year-old boy.
He also said land below the high-tide mark was disappearing forever under water.
"People walk over to the island at low tide and decide to stay the night illegally and cut down the mangroves and this leads to the degradation of the beach," Mr Parker said.
"The mangrove roots keep the sand in place and allow more deposits of silt so the beach remains or grows.
"But when those roots die because people are chopping down the mangrove, the beach starts to erode and wash away."
Along with the historic photographs, further anecdotal evidence of the island's shrinkage is found in Cleveland historian Peter Ludlow's book Moreton Bay People - The Complete Collection.
The book details diary entries from one-time King Island resident Clarrie Phillips, whose family lived on the island from December 1904 until April 1906.
Mr Phillips, who still lives in Redland, wrote in his 1980 memoirs, King Island was "only a skeleton compared to what it was when we lived there".
"About half, or even more, has washed away. This was caused by the local council cutting down all the mangrove trees about 50 years ago (in 1930).
"I would estimate that originally there was about half an acre of thick vine scrub comprising some sizeable trees, including dogwood, ironwood, cotton trees," he wrote.
Although how much King Island has shrunk is unknown, the island remains one of the most highly visited conservation parks in Moreton Bay.
Precise visitation figures are not available, but at low tide large numbers of people regularly walk from Wellington Point to the island.
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