Alien trees pose a threat

Alien invasive gum trees are a concern on the South Coast although local conservancies are getting to grips with the problem.

THIRSTY alien plantation escapees like pine and gum trees are depriving the South Coast’s natural vegetation of water and are elbowing their way into the last precious patches of our natural coastal bush.

South Coast property owner Piet Coetzee, who conscientiously made sure all alien invasive plants were removed from his land after he bought it, has expressed his concern about the amount of pines and gums that seemingly thrive undisturbed in many South Coast areas. Was anything being done about the problem?

According to the Wildlife and Environmental Society of South Africa (Wessa) pines (Pinus patula) and saligna gums (Eucalyptus grandis) are both category two invaders. This means they may only be grown with a permit under controlled circumstances, in demarcated areas.

They are not allowed to be cultivated within 30m of the 50-year floodline of watercourses, lakes, dams or wetlands.

Saligna gums, introduced from Australia for timber, shade, firewood and as a pollen source, are voracious water drinkers. They lower water tables, eliminating indigenous plant communities and transforming the landscape. Specific registered herbicides are used to control them.

The patula pines that have become such a nuisance here were brought from South America to South Africa where they were commercially planted for timber.

Their seeds germinate easily and they quickly invade grassland, road reserves and forest margins. They elbow out the native plants, transforming the landscape and they increase the risk of fire.

You can easily remove seedlings and saplings by hand and mature plants can either be ring-barked or felled. Herbicides are not, therefore, necessary.

The good news is that many of these invasive alien trees have already been given their marching orders, thanks to vigilant members of our local conservancies.

According to local conservationist Dave Hallé, who has been involved in pioneering the South Coast’s urban conservancy movement, most of the 16 conservancies and conservation organisations on the South Coast were actively involved in invasive alien plant control and, at one time or another, had actively targeted pines and gums.

A number of the conservancies had worked with contractors who had been willing to remove gum trees at no cost provided they’d been able to retain the felled trees.

“This has resulted in quite a number of problem alien trees and other plants being removed. After years of battling the invaders, we are at last starting to see some result. Invasive aliens are a major problem worldwide and keeping them under control is imperative. If you are worried about the problem of alien plant control, the best thing you can do is to join your local conservancy,” Dave said.

He and Alex Skene, the chairman of the local conservancies’ umbrella body, the South Coast Conservancy Forum, said that it was necessary to work with the local authorities to ensure the proper authorisation was obtained before embarking on alien plant control programmes in public places.

Alex said the conservancy forum had formed a good partnership with local municipalities and environmental organisations regarding alien control. The forum was also part of the KZN Conservancies Association and was therefore part of an integrated provincial effort to deal with environmental matters including alien invasives.

According to Ray Nkonyeni Municipality spokesman Simon April, the municipality did not yet have an Alien Invasive Plants Management Plan but was in the process of developing it as it was a legal requirement to have one.

Regarding overgrown private plots of undeveloped land, which are often infested with invasive alien plants, he said the Community Services Department was involved in the clearance of these plots, depending on certain conditions.

The Working for the Coast Programme, another weapon in the war against aliens, was still in place. The municipality’s environmental section always integrated the issue of alien invasive species management in its environmental awareness programmes, he said.

If you would like to join the fight against alien invasives by joining a local conservancy, contact Alex at 078 5087290.


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Judi Davis

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