We're Dreaming Of A RED Christmas.....
Landcare Research scientists say special care must be taken to halt the decline of our native Christmas trees and plants, and that the Christmas favourite, holly , is becoming a weed.
There are fewer pohutukawa seen along New Zealand’s northern coastlines, and northern and southern rata numbers are also dwindling. Less well known is the fact that the five species of native mistletoe may disappear from many areas without intervention.
According to tradition, anyone who stands beneath a sprig of mistletoe must receive a Christmas kiss, and is magically protected from harm whilst they stand there. But Landcare Research forest ecologist Peter Sweetapple says the mistletoe itself needs protection from harm, and is officially listed as a declining species.
“It’s faring pretty poorly except in parts of the South Island and some isolated areas. It’s disappeared entirely from large parts of the North Island.
“Possum browsing is a major factor in this, but when possums are controlled to very low numbers, mistletoe can spring back dramatically. We’ve seen this with the very showy Peraxilla tetrapetala in the Nelson Lakes mainland island. Also, at Waihaha, west of Lake Taupo, Tupeia antarctica foliage was almost completely absent before possum control, and reappeared and flourished after possum control measures. But when possum numbers grew even slightly, the recovery reversed”.
Peter Sweetapple also says that people should learn a lesson from the past, and refrain from picking mistletoe for Christmas decorations. “Picking contributed to the decline of Trilepedia adamsii, thought to have become extinct in the mid 1900s.
*A reduction in seed-dispersing birds may be another problem for mistletoe”.
The dramatic blooms of northern rata are now only really seen in scattered areas of lowland forests in the North Island and northern South Island. Numbers are severely depleted, and most reports are of adult trees, not seedlings or saplings. Unfortunately for northern rata, they’re a favourite of possums.
“Northern rata are often the first trees possums attack when they move into a new area.” says Landcare Research plant ecologist, Dr Bruce Burns. “But for some reason, some individual trees don’t appeal to them. We hope to study the genetic and environmental bases of variation in palatability.
“Luckily, northern rata often survives possum attack, unless there’s a compounding factor, like drought.”
Southern rata, New Zealand’s most widespread tree, puts on a glorious New Year display, and the Otira Viaduct area of SH73 is THE place to see it. But southern rata is dying in big numbers over large areas, and the causes have been argued about for decades. The timber is extremely durable, and in places like the Kokatahi valley on the West Coast, spars from trees that died 60 years ago are still visible.
“The path to southern rata’s demise is manifold and complex” says Landcare Research plant ecologist, Dr Peter Bellingham. “There’s no doubt the leaves are a preferential food for possums. But do possums kill trees that were going to die anyway, or do they shove them over the edge? Insects, fungi, and storms can also contribute to tree deaths.
“It’s difficult to say whether new populations are arising quickly enough to replace the old. In some valleys they are, in some they aren’t”.
New Zealand’s most famous Christmas tree, the pohutukawa, is a problem weed in South Africa, but is having a hard time in its native country. Most of the glorious trees seen mainly on northern North Island coastlines are old trees, and there is very little regeneration in the established population.
*Getting rid of possums is a good step towards ensuring a thriving pÇhutukawa population* says plant ecologist Dr Ian Payton. *But it*s only a first step. We as people have to modify the way we act around pÇhutukawa.
*Land clearing for farming in areas such as coastal Northland could be a major cause in their decline. Stock trampling can destroy roots, as can cutting drains close to the tree, and grass fires. Also, pÇhutukawa don*t cope well with competition from introduced grasses, which block the seeds from taking hold.
*I hope that through intensive efforts to protect and propagate pohutukawa by individuals and groups like the Project Crimson Trust, the outlook for the tree may be more positive*.
And finally, a warning: a traditional Christmas favourite, holly, is becoming a forest weed, and is displacing native flora.
One of the earliest plants to be introduced into New Zealand, holly is bird dispersed, and tends to invade mainly bush and light scrub close to towns.
Landcare Research plant ecologist Dr Peter Williams says holly can be a real problem, as it*s persistent and long-lived, and can grow as high as 12 metres.
*I recommend that people don*t plant it at all, unless they live WELL away from any forest patches*.