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Clarky's Comment - Can Red Zone land support commercial forestry?

Under the new National Environmental Standard – Plantation Forestry (NES-PF) New Zealand’s rural land has been classified according to its susceptibility to erosion. A traffic light ranking is used with red being the most at-risk land. Approximately 2/3rds of the commercial plantations in the Gisborne District Council’s region are on red zone land. Some of this land was planted by the former New Zealand Forest Service, providing both land stabilisation of past failed farmland and employment. Another wave of planting took place from 1979 when BP and Fletcher Challenge Forests formed the Hikurangi Forest Farms JV and planted parts of farms while retaining grazing on the best portions. Then following cyclone Bola in 1988 many farmers looked to sell up as with vast quantities of topsoil gone and fences destroyed the economics of dry stock farming turned marginal at best. 

After Cyclone Bola central government and local Catchment Board (now GDC) encouraged the planting of commercial pine forest with grants and subsidies. 

From 100% indigenous forest cover, cleared by early settlers, we went to virtually 100% pasture, and now we have at least some parts of the GDC Region that have been converted back to forest cover as commercial pine forest. MPI data tells us that 104,000 ha of red zone land is now in plantation forest cover, while approximately 180,000 ha of red zone land remains under pastoral farming and is therefore fully exposed to another cyclone Bola type mass soil-loss event – more than is protected by plantation forest cover. 

Although it is widely acknowledged that forest cover protects soil during storm events, the recent Tolaga Bay storm has highlighted what can happen following harvest and replant but before the next crop achieves canopy closure – a 5 – 6-year “window of vulnerability”. Not only is the land exposed to massive soil loss, but along with that comes woody debris from the last harvest that is sitting on the cutover land and picked up during the landslides. Although loss of this woody debris is not nearly as damaging to the long-term land productivity as the loss of soil, some of it ends up, along with the sediment, on the farmed coastal floodplains or beaches. 

What is the best use of this erodible hill country? Abandoning commercial forestry is no more sensible than suggesting all dairy farming should cease because it puts excess N into the waterways. If the Regional Council conditions put on harvesting make that harvesting uneconomic, commercial forestry would cease - end of story.  Also gone would be thousands of well-paying East Coast jobs.  Nor is the wholesale change to different species commercially viable under current ETS settings, and even if it was there is still 20+ years of pine harvest to deal with. 

The forest industry has been examining what can be done differently to reduce the consequences of land sliding occurring during extreme storms in the periods when soils are exposed between rotations. Anyone with a basic understanding of New Zealand’s geology will know that it is not possible to eliminate land-sliding or debris flow occurrence. Leaving wide buffer strips will help arrest material entrained in flood waters where slopes flatten out before the stream but will do nothing to stop tonnes of earth and logging slash entering waterways in steep incised valleys.

Redwoods are a real option for pasture land planting as they are a viable carbon capture crop with long life and roots that do not rot when the stem is cut down. If the ETS settings support higher carbon prices we can expect more interest in redwoods for some red zone pasture land. Redwoods may also have a place as natural debris traps at the bottom of slopes when replanting pines for harvest.

Natives grow too slow to be of commercial interest for carbon farming. Plus, there is a very real possibility that planting natives will see the land designated as a Significant Natural Area under the RMA at some future date, meaning huge constraints on land use flexibility and land value. Any large-scale planting of natives would need to be for non-commercial purposes or very heavily taxpayer subsidised.

Man-made debris traps will have a place in certain catchments. Those that were in place during the recent Tolaga Bay storm were overwhelmed but in a less intense storm they can hold back debris. 

Tethered machine logging in combination with different felling heads can reduce breakage and will work on certain slopes. 

Flood banks on at-risk rivers and streams bounding floodplains are also part of the answer, not just for logging slash containment but also for sediment deposits over pasture and cropping land. And no permits should be issued for buildings on at risk flood plains. Let’s not be surprised if such buildings that are already in those at-risk situations become uninsurable as we encounter more intense storms more frequently. 

So can commercial forestry work on red zone land? Yes, if harvesting and other measures (e.g. flood stop-banks, debris traps) minimise the risk and there is community education and acceptance that the harvest phase exposes down-steam properties to some residual risk. If there is zero tolerance for risk and harvest consent rules that support that, then no.

I would like to extend an invitation to clients and would-be clients to our Forest Harvesting Seminar being held in Whanganui 29 August 4:30pm to 6:30pm. Please click here for more information.