By Rebecca Macfie
To counter climate change, New Zealand must vastly increase its area of forestry. But as recent disasters show, not all trees are created equal.
Two years earlier, on the steep slopes above Loudon homestead, 300ha of Pinus radiata owned by local forestry investors had been clear-felled. Trees had been harvested up to the edge of Waieke Stream, which flows through the forestry block and the Loudon farm and into the harbour. The forestry contractors had carted the good logs away, and the land was left with the usual post-harvest covering of debris – years of thinnings and prunings, and sawn logs that the contractors had left behind. In the year after harvest, the block had been replanted with a new crop of radiata seedlings.
Sometime before dawn on July 22, the denuded hillside let loose a torrent of mud, felled trees, forest detritus called slash, silt and weeds into Waieke Stream. King and his forestry adviser, Mark Belton, believe the debris formed dams in the stream bed. The water built up until the blockages blew out, sending surges of trees, rock and muddy water downstream through Loudon farm.
The debris flow demolished standing trees in King and Lovell-Smith’s permanent woodlot, dumped thousands of tonnes of logs across their land, destroyed fences, damaged farm tracks and stockyards, scoured out the stream bed, flooded one of the homes on the farm up to the windowsills, and left a thick layer of clay and silt across productive flat land. Even now, 10 months on, Loudon is littered with tangled heaps of pine logs and mounds of silt and debris.
King and Lovell-Smith are still paying for the clean-up and repairs – King says the bill is likely to come to $1 million – and they are fighting for accountability. Environment Canterbury, which should have required the forestry company to obtain a resource consent for harvesting but wrongly advised that one wasn’t needed, has decided not to prosecute anyone, despite its investigator’s assessment that the “catastrophic flows” of sediment and logs have damaged aquatic life in the stream and dumped a large volume of sediment, logs and debris into the harbour.
The forest management company, PF Olsen, denies liability and says the flood was triggered by an old slip that was activated by the intense rain. Belton believes the calamity is “entirely” a consequence of the logging operation.
Whatever the outcome of the argument, the disaster at Loudon farm is instructive. New Zealand is on the eve of a new forestry boom. The Government wants to plant a billion trees over the next 10 years. In its draft report on how the country can move to a low-emissions economy, the Productivity Commission says we need to increase the land planted in forests by 1.4-2.8 million hectares. The question is, what trees should be planted, and where?
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