Planted protection forest
There are also significant areas of ‘planted protection forest’, which is additional to ‘natural forest’ and ‘planted production forest’ (see next section). Protection forests are established for soil conservation purposes. Species used for gully and mass movement erosion control include willows, space-planted poplars and close-planted radiata pine.
In protection forestry, tree spacings vary widely, ranging from space-planting (fewer than 100 stems per hectare) to close afforestation (more than 1500 stems per hectare). Conversion to a notional total planted area is impractical, and there are few readily available statistics on these forests. However, in the period 1969-1987, tree plantings for protection forestry were:
- 4,590 kilometres for gully control; and
- 10.6 million space-planted trees and 16,685 hectares close-planted, for mass movement erosion control.
Between 1945 and 1985, farm conservation plans were established on 5,923 properties, totalling 6.4 million hectares. On North Island hill country farms situated on susceptible soils, some 80% of land may require soil conservation "treatment". It has been estimated that by 1985, about two-thirds of unstable areas on such farms had been treated. Protection forestry is only one of a number of soil conservation techniques, but on unstable land it is likely to be preferred.
The distinction between ‘protection forestry’ and ‘production forestry’ is not always clear. Close-planted radiata pine forests, originally planted for protection purposes, may eventually be harvested. Similarly, there are areas of production forests that will never be logged because of the environmental risks. However, there has been very little use of soil conservation poplar and willow plantings for wood production.
Much of the environmental benefit from planted forestry — whether for protection or production — arises from a change in land use from unsustainable pastoral farming. In New Zealand planted forests are well recognised as providing a protective and production role. Forests planted for protection purposes are able to be harvested using sensitive techniques, particularly using skyline hauler systems. Planted forests provide a wider diversity of both plant and animal species than pastoral land. An understorey of different plant species normally occurs in a well-managed forest. The understorey plant species are often natural species which provide a habitat for many animal species.
Contact for Enquiries
MAF Information Services
Pastoral House
25 The Terrace
PO Box 2526
Wellington, NEW ZEALAND
Fax: +64 4 894 0721
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