Northland was feeling the axe first but other regions would soon be affected, too.
While the Government had counted on the national yield remaining around four million tonnes and sustaining local industry, indications were there would be half that tonnage available in five years, Dr Tanner said.
"Yet there will be the same demand."
Recently ousted Northland MP and the leader of New Zealand First Winston Peters has consistently called for the government to help put the handbrake on a situation jeopardising the country's timber backbone.
"We have been cavalier in the extreme to think we can continue to sustain this industry without checks in place," Mr Peters said.
He said industry boards and lobby groups which might help influence Government policy were not strong enough "because they are swayed by the overseas forestry companies who are in the majority in that group".
Mr Peters said central government, not just local economic development sectors, needed to get behind Northland processors and forestry owners.
"To compromise is so disadvantageous for the Northland economy and people," he said.
"We won't get any growth or development in the north without protecting and planning for local industry."
On Friday, Mr Peters told the Advocate Labour, NZ First and the Green Party agreed about the need to rethink the current free market frenzy that applied to the forestry industry.
He implied some controls should be put in place.
He said he would not go as far as calling for Government intervention.
"Intervention is the wrong word.
"But this is the country's third biggest export earner and they need to take a tougher stance on it.
"The markets they'd lose are the ones with the lowest possible worth to New Zealand.
'"Well, let them go. You've got to compete at the top, not the bottom."
Shane Horan from Waipapa Pine said there were two problems impacting on local processors: one was that fewer trees being planted; the other was the volume and rate of the current harvest and export.
The wood processing industry directly employed 1400 people between Kaitaia and Waipu, and indirectly ensured work for thousands more, Mr Horan said.
However, it was totally dependent on forestry.
"Forestry investment is very important to the longevity of the manufacturing industry but we need investors prepared to support local wood processors," he said.
Dr Tanner said that unless a quota system or other regulation was imposed, the bulk of raw timber would continue to be exported.
While it attracted high prices due to strong international demand, the export grab and lack of support left local processors struggling to grow value-added manufacturing.
Instead, value was added in countries where manufacturing was subsidised by their own governments.
"And guess what? The products come back here and then we pay for them again," Dr Tanner said.
