Dick Bellamy: Our hillsides are being scarred by poor forest harvesting

Photo / Alan Gibson

Forest plantation harvesting is in desperate need of improvement.

Last month I spent four days in the Marlborough/Nelson area. We drove extensively around Marlborough and visited Nelson for the day.

The weather was stunning, the grape vines in Blenheim and the Awatere Valley were in their autumnal golden phase and the skies were crystal clear. It was a splendid experience.

It would have been a stunning experience had we not kept looking at the landscape in the background. Much of the Radiata forests planted in the Marlborough-Nelson region are now being harvested.

All panoramas are now backed, in almost every direction, with hillsides that look like tilted battle scenes taken from old photographs of the Somme or Vietnam.

I refer to the methods used by forest harvesters to remove the logs from the hillside. These methods have been refined in recent years into an appalling destructive exercise in clear felling. Logs, tree tops and stumps are left covering the slopes and filling the valleys.

Moreover, because the surveyed property margins are straight line boundaries, often running up very steep ridges, these scenes of destruction usually appear as triangular or square shapes against the rounded contours of the hillsides.

What seems to occur in forest harvesting appears to proceed like this. First a bulldozer carves access tracks as a series of ugly zig-zags up the hillside, pouring earth and silt into the valleys in the process.

Then the cableways are mounted on platforms cut into the ridges and the men with chainsaws go to work. The logs are then cabled down to the bottom, the waste being simply discarded where it falls.

Then the waste wood begins to rot and bleach and the weeds emerge. At some stage new trees are planted or seeds germinate, but meanwhile the trashed slopes are bare and stark for about the next 10 years depending on planting densities and growth rates.

Meanwhile, the access tracks erode and further scar the hillsides. The end result is an absolute mess and it provides a terrible commentary on our inability to manage the New Zealand environment.

The lovely town of Nelson can now only be viewed against a background image of widespread destruction. Is this what we want as our international tourism image?

I am appalled that in the 21st century we in New Zealand are still allowing forest harvesting to proceed in this manner. We all know that civilised countries control this process, the most obvious starting point being the requirement for harvesting to occur progressively in defined contour strips.

Other more civilised jurisdictions in the Northern Hemisphere also require marginal strips to be left to protect waterways, sightlines, and general amenity. All these techniques have been well studied and adopted overseas and research in New Zealand by the (former) Forest Research Institute and others has yielded solutions.

So it's not hard to work out what would make the impacts of tree felling more acceptable. Trees do form an important part of our national income, but vandalism is too high a price for the community to pay.

We are a country with generally high rainfall. When it rains hard, clear-felled areas on hillsides are unprotected and therefore the runoff is almost immediate. Strangely enough, in that situation, silt, logs and debris end up travelling down the steep slopes.

In the "weather bomb" downpour last month, water-driven forest debris swept through a small settlement in Nelson and destroyed it. We have known for many years that those types of event will happen with uncontrolled clear felling when the hillsides are stripped bare.

The Soil Conservation and Rivers Control Act (1941) was enacted in response to these types of incidents.

So what are our Regional Water Boards and Regional Catchment Commissions doing about this problem? The answer, it seems, is nothing much, at least in Marlborough and Nelson. The time is overdue for the relevant Ministries in Wellington to intervene.

There is no reason why we should not continue to have a viable forest industry, but if we are to continue to have plantation forests, there needs to be a harvesting plan formulated.

The industry needs to understand the environmental impact it creates and its social responsibilities. And it needs to become an industry that does something about improving its harvesting practices and its image.

* Emeritus Professor Dick Bellamy was formerly Dean of Science at the University of Auckland.