Driving home the last of 25,000

Among the last of 25,000 poplar and willow poles being planted for soil conservation in 2010 were driven home at Eringa in Longbush Valley east of Carterton last week (17 September).

Greater Wellington manager land management Dave Cameron says the 25,000 poles have been planted across 350 hectares of erodible hill country pasture in eastern Wairarapa this winter, over 150 properties. The overall budget for this component of the 2010 budget was $565,000

Mr Cameron says the large, fibrous root system of poplars and willows helps bind the soil in erosion-prone areas, and keeps it intact for grazing.

“The roots keep the soil on the hills where it is supposed to be and keeps these areas viable for farming. This also keeps large amounts of sediment out of our streams and rivers, which is good for water quality.

“There is a standard recipe of about 70 poles per hectare. These are sufficient numbers to bind the soil but doesn’t stop the grass growing. Poplars and willows are particularly useful as they are one of the few trees that will establish roots from a piece of branch driven into the ground. After a couple of years most trees are well established.

“This method of soil conservation has been in use for about 50 years and became widespread in Wairarapa after the storms and slips of 1977.”

Most of the poles are grown by Greater Wellington at the Akura Conservation Centre in Masterton and the Mangapakeha Nursery near Tinui.

A three metre pole and plastic sleeve, to protect it from stock browse, costs $12. Landowners who have a Soil Conservation Farm Plan with Greater Wellington are subsidised between 30 and 60 percent of the costs.

There is about 100,000ha of erodible hill country in eastern Wairarapa, mostly on siltstone and mudstone soil.

Mr Cameron says in cases where erosion has become so bad that it is no longer profitable or sensible to farm Greater Wellington recommends retiring the area from grazing altogether.

In these cases Greater Wellington Land Management Officers recommend production forestry, reversion to native forest or a mix of both.

The Akura Conservation Centre has sold 300,000 pine seedlings in 2010 for 232ha of pine plantings in eastern Wairarapa.