Northland Totara Working Group spokesman Paul Quinlan tells people about the programme for the Titoki field day. Photo / Mike Barrington
Advice on turning "weed" totara trees on Northland farms into high-value wood drew about 50 landowners to a Northland Totara Working Group field day on Ian and Helen Hilford's dairy farm near Titoki.
The Hilfords milk 350 cows on about 170ha with some of the rest of the 230ha farm including bush-clad gullies and slopes where Tane's Tree Trust is thinning and pruning regenerating totara and managing mature trees with the intention of future milling to establish the value of caring for the native vegetation.
The field day included an inspection of the regenerating totara and addresses by several speakers.
Former Forest Research Institute scientist David Bergin, now operating Environmental Restoration Ltd at Rotorua, said many Northland farms had totara ranging from forest seedings to trees up to 200 years old.
Some landowners regarded them as a nuisance, but with management they could be a better farm asset than grass in gullies and on slopes.
Thinning could double the growth rate of tall, straight regenerating totara, but it took about 60 years for a tree to reach 50cm diameter, around 100 years to produce quality sapwood and much longer to form heartwood totara, famed for its durability.
Most of Northland's 600-year-old totara with red heartwood had been felled for uses such as fence posts.
But many farms had totara 120 years or older with lighter coloured sapwood suitable for above ground cladding and internal building construction or to make furniture.
Dr Bergin said logging of these trees could be carried out and the gaps created by their removal filled with young totara or other native trees, complementing pasture and farm pine plantings.
Professor David Norton, from Canterbury University School of Forestry, covered biodiversity values and enhancement opportunities with totara forest on private land.
A paper he produced in conjunction with Laura Young says mature and regenerating native forest and manuka/kanuka on public conservation land and QEII covenants comprises 10 per cent of Northland while similar native woody vegetation on private land comprises another 18 per cent.
While most forest on private land was not "old growth", it increased the total area of native forest in Northland from 10 to 28 per cent, which substantially improved connectivity, which was important for native fauna, particularly birds.
One Northland study found the maximum distance brown kiwi travelled across pasture was 330m but they were capable of walking between reserves up to 1.2km apart if small forest remnants were present to act as stepping stones.
Northland Regional Council hill country land management adviser Michael Mitchell described how the council last December launched a four-year project to curb erosion of pastoral land on hill country in the Kaipara catchment with the aim of reducing sedimentation of the Kaipara harbour.
The Ministry for Primary Industries funded project also focuses on returning trees to the land as some pastoral hill country is too steep and erosion-prone to be farmed sustainably under pasture.
Mr Mitchell said midway through next year the council hoped to complete an economic analysis on changing marginal hill country grasslands to more sustainable land uses.
A simple calculation tool which land owners could use to assess the economic viability of marginal grasslands compared with other sustainable land uses was also on the drawing board.
"We hope to motivate a shift toward the use of trees as a more sustainable option for this marginal land to reduce hillslope erosion," Mr Mitchell said.
The economic analysis would include combining stands of exotic trees such as pine and poplar with native vegetation and stands of trees including totara, using manuka as a nurse crop for later-developing totara.
"We also hope to attempt to put a dollar value on the range of other ecosystem services which totara and other planted trees provide, such as flood control and water quality," Mr Mitchell said.
"But trying to put a value on some of these services could become very complicated and would possibly be unachievable due to the complexity of variability of the factors involved."
Ministry for Primary Industries official Mark Hollis was at the field day to talk about legal issues associated with harvesting totara.
Seeking an accurate account later of what he covered, The Country was referred to the MPI media team, which provided a statement by the ministry's director spatial, forestry and land management, Stuart Anderson, who said Part 3A of the Forests Act 1949 gave owners of private indigenous forests options for managing their forests in order to harvest and mill indigenous timber.
"Those provisions also apply to naturally regenerated farm totara. Sustainability prescriptions required for the approval of Sustainable Forest Management (SFM) plans are listed in Schedule 2 of the Forests Act," he said.
"These are in place to ensure the harvest of indigenous timber occurs in a manner that maintains the natural integrity of the forest and that the rate of harvest is at a level which the forest can supply in perpetuity.
Note that under the Forests Act, MPI has no jurisdiction over landowners who wish to merely clear totara from their land and do not intend to mill the timber - this is regulated under the RMA by the relevant territorial authorities."
The Northland Totara Working Group had proposed to simplify the application process to make it more accessible to landowners wishing to gain an economic return from the totara on their land.
"MPI recognises that farm grown totara in Northland is unique in the way it relatively quickly colonises grazed pasture land. Likewise MPI recognises that there are many positive ecological outcomes in maintaining and increasing this resource, such as sustaining and enhancing the health of waterways and carbon sequestration," Mr Anderson said.
"We know landowners who have little or no forestry knowledge find the process of setting up a SFM plan difficult and time consuming, and that at times a more appealing solution is to inhibit totara regeneration to maintain pasture cover.
"Therefore we have previously provided a SFM plan template unique to totara to help simplify the process. While this has gone some way to addressing the working group's concerns, they still consider some aspects of the process excessive.
While there is flexibility in applying the Forests Act requirements to reflect the characteristics of different forests, the need to satisfy all the prescriptions listed in Schedule 2 of the Forests Act does mean that applying for a SFM plan for farm grown totara will always involve a level of complexity."
He said MPI continued to work with the working group to make the SFM plan process more workable for landowners while maintaining consistency with the Forests Act.