Forest owners say the damage done by the recent storms will cost the industry up to $5 million.
The Nelson region was hit hard, but most of the rest of the country got off lightly.
Hancock Forest Management general manager Bill McCallum, says his staff flew over their Nelson holdings on Thursday and are now drawing maps of the damaged areas.
Mr McCallum says the company lost more than 100,000 tonnes of wood, especially in the hills to the east of the city, but still hopes to recover 80% of the fallen timber.
But an industry consultant, John Hornby, says harvesting the wood will be a dangerous and costly operation.
Industry sources say every forest owner in the region was affected to some extent.
They estimate at least 1000 hectares of trees were lost, worth up to $5 million.
