Environment

Poplars for erosion control

 Poplars in Northland

Poplars used for erosion control in Northland.Why grow poplar poles?

Poplars are a fast-growing species ideally suited to both prevent and control erosion due to their extensive and deep root network.

 

As they lose their leaves at the end of each growing season, they do not significantly affect grass growth over the cooler winter months and pasture beneath them can continue to be grazed. (However, temporary destocking, electric fencing or protection with plastic wraps is recommended until trees have become established; this typically takes 18 months to two years.)

 

Species and varieties of poplar favoured in Northland include Kawa, Toa, Veronese, Crow’s Nest and Margarita and can be used on a wide range of sites and soil types to control slip, slump, earthflow, streambank, tunnel gully and gully erosion.

 

To ensure trees grow straight and well when planted out, poles are best grown in special-purpose nurseries. While some enthusiastic landholders may be able to manage a nursery to meet their own needs, most people prefer poles to be delivered in bundles ready for planting.

 

Establishing your poplars 

  • Rotary hoe 0.5m – 0.75m strips; this will help root stock establish and control competition from other plants. We also advise the use of weed matting to control unwanted competitors until young trees are established.
  • Ensure a 2m to 2.5 metre gap between rows.
  • Plant 150mm long, 20mm diameter cuttings (buds pointing up!) at one-metre intervals within rows.
  • Thin back to a single shoot per cutting and trim off any side branches that grow in the first year.

 

Cropping

Poles can be cut as one-year or two-year poles.

 

One-year poles can only be used in areas from which all stock is excluded and because they are lighter, these poles are also more susceptible to drying out on difficult sites.

 

Remember, there will be only a single pole in the first crop from each cutting if cut as a one-year pole. However, there will be two poles (1 x 2-year and 1 x 1-year; the top) if the initial harvest is left until the second year.

 

Poplars at Tangiteroria.Poplars at Tangiteroria.

 

Useful links and resources

 

PDF logo.Erosion in Northland fact sheet (1 MB)

 

PDF logo.Poplars and willows fact sheet (222 KB)

 

PDF logo.Growing poplar and willow trees on farms (1 MB)

 

Visit the NZ Farm Forestry Association's website for more information on poplars and willows:  http://www.nzffa.org.nz

 

Visit the Ministry for the Environment's website for more soil conservation information:  http://www.mfe.govt.nz

 

For more information

 

Interested individuals, groups and organisations are encouraged to contact:

 

Wayne Teal
Land Management Advisor
Northland Regional Council
Phone: 0800 002 004
email: mailroom@nrc.govt.nz