Erosion control in forestry blocks

Before planting your forestry block consider how you can manage the erosion risk on your land, such as having buffers around the most vulnerable areas or planting them out in permanent vegetation.

Erosion

Erosion is the geological process in which earth materials, such as soils, are worn away and transported by wind or water. New Zealand’s hill country is primarily affected by two types of erosion, fluvial surface erosion and mass movement erosion.

Some areas in New Zealand have severe erosion problems. This causes long-term damage to the productivity of rural land. It threatens communities and rural businesses, including farms and orchards, roads and bridges. Water quality is lowered when large amounts of sediment enter river systems, and it harms the natural and cultural values of the land and the coastal environment. This results in an economic impact on hill country farms, infrastructure and high quality land on floodplains.

Removal of vegetation cover increases the risk of erosion and afforestation reduces the risk.

Planting a new forest

If you are planting a forest for harvest you need to understand the erosion risk on your land to determine:

  • how you manage forestry activities
  • if your land is suitable for the type of tree planting you want to do
  • any afforestation rules that apply under the National Environmental Standards for Plantation Forestry.

Your local council is a good source of advice for managing erosion control on land. If you are planting any kind of forest they can also provide guidance on any vegetation clearance rules that could apply to your site.

When you plant your forest you should think about activities that will affect soil conservation. Some things to think about include:

  • Planning how the forest will be harvested and logs removed. For example, the most efficient place for roads and landings to reduce the amount of earthworks required.
  • Having buffers of permanent vegetation around vulnerable areas like waterways or gullies.

Areas prone to erosion

In your most vulnerable areas, consider planting:

  • Permanent native vegetation. For example, some of the more vulnerable gullies could be planted in manuka.
  • Species with long rotation times that also coppice from the stump, such as eucalyptus or redwoods.
  • Continuous cover forestry – either native or exotic.

More information on soil erosion

Check out the below to find out more about soil erosion in New Zealand and forestry regulations.