Until surprisingly recent times it was government policy to clear all native bush from land that could prove suitable for agriculture. Fertile plains, such as those that constitute much of the Manawatu, were early stripped of their forest. One of the few fragments of bush in that area to escape was an 11-hectare block originally part of a native reserve for Ngati Kauwhata near Feilding, but in the 1870s it was leased, then purchased from the tribe.
The absence of bush in the district must have been quickly felt, for locals attempted to buy the land as a reserve to commemorate Queen Victoria’s jubilee in 1897. The owner, a Mr Riddiford, refused to sell, considering that “once he handed it over to a local authority, the bush would be destroyed by carelessness.”
The words proved prophetic. The Borough Council acquired the block in 1916 after Riddiford’s death, and it came to be known as Kitchener Park. Its undoing started some years later when cattle were grazed there. Later the Catchment Board realigned the stream that marked the edge of the bush with a bulldozer, which, apart from the direct damage it caused, dried out some of the lower ground occupied by huge kahikatea. Many of the big trees started to die.
In 1970, severe drought killed most of the tawa. However, more serious than any of these was the invasion of the bush by the creeping weed Tradescantia fluminensis—commonly called wandering Jew (right). Nobody is now sure when this menace appeared, but Michael Greenwood, who first became involved with the park in 1944, recalls that it was well established by that time. The invasive weed built up a thick blanket—in places over a metre deep—over the floor of the forest, smothering ferns, mosses, shrubs and herbs, and preventing all regeneration. Fencing out the cattle only helped its growth.
Alan Esler, retired botanist and author of a book on the botany of Manawatu, recalls an episode that gives some idea of the scale of the problem. “About 12 years ago a Scout jamboree was held nearby, and, as a community service project, Scouts pulled out Tradescantia for a day or two. In the heaps they had piled up around the fringes of the bush I calculated there were 200 cubic metres of the weed.”
Although Kitchener Park was close to dead, and certainly buried, it was not forgotten. It had had a proud heritage. H. H. Allan, author of the well known New Zealand Trees and Shrubs among other books, and later director of DSIR’s Botany Division, was not the only botanist who had picked up a lot of his early knowledge from browsing among its boughs. He had made a detailed survey of the flora in 1928 (finding 140 species), and a new species, Fuchsia perscandens, was described from material he discovered there . An unusually wide range of lichens—many of them resident on tree leaves—was also uncovered by Allan.
But the park won a new sort of notoriety for species loss. In the 33 years following the survey, no fewer than 60 of Allan’s 140 species vanished from the bush.
Yet the lowland semi-swamp forest that Kitchener Park represents was now almost extinct in Manawatu, and almost no unmodified remnants persist anywhere in the North Island. Despite its decimated understorey, many large old podocarps-kahikatea, matai and totara-remained: one of the best collections in the Manawatu. Some claimed that the bush also contained the tallest kowhai tree in the country.
Gavin Scott, a keen botanist, pastor of a local church and chaplain of a freezing works in the area, saw an opportunity to resurrect the park and give redundant workers something to do when the works closed in 1991. He secured funds from the Manawatu District Council to employ a team of ex-freezing workers in clearing the Tradescantia from the floor of the bush.
This was a daunting task. Tradescantia doesn’t spread by seeds, but vegetatively. Any morsel will root, so literally every fragment must be removed. Herbicide was used to knock the masses of weed back, but it was unable to completely kill the weed, so elimination was a matter of picking out every molecule, on hands and knees.
The work has continued every year since, although besides ex-freezing workers, at-risk youth and school groups have become involved—thousands of hours of work, much of it voluntary. So far, two-thirds of the area has been cleared, and it is hoped that the whole park will be free of the pest by the end of 1996, as long as modest funding continues.
As well as weed clearing, walkways and paths have been laid, and some planting has been carried out. In the two decades before the work started, the species count had fallen to about 42, but it should start to increase now that air-borne spores and bird-carried seeds have a chance to germinate.There will be a re-dedication of the park in February 1996, 80 years after the official opening.
The battle for Kitchener Park is not yet won. Tradescantia is a cancer that can always return though apparently eliminated, either from fragments washed down the stream or left lurking in the ground. Almost alone among imported plants, it can grow in the dense shade present in the interior of our native forests. Vigilance will be required for years—if not decades—to preserve the hard-won gains.
But the broader significance of Kitchener Park is that the battle is possible elsewhere. For several years we have succeeded in rolling back the invading animal tide—rats and possums have been eliminated from a number of islands, and possum numbers reduced in a number of mainland forests by aerial poisoning—but pestilential plants in forests have felt pretty safe.
Thanks to the dedication of Gavin Scott and his helpers, they have reason to tremble at last.