The June floods that swept a "tsunami" of slash into Tolaga Bay have forced a reset of our views on commercial forestry practices.

Once seen as the solution to management of steep erodible land cleared of native forests by previous generations for farming, this event appeared to raise more questions for forestry than there are known available solutions, or tree species we can sensibly plant, to address them.

With the frequency and intensity of storm events increasing through climate change, it would seem that leaving large areas of steep back country land bare between crop rotations, apart from the residual slash which is uneconomic to remove, is not going to work anymore.

While actually quite distinct management issues, slash and sediment understandably combine in the public's perception, just as they did within the affected rivers and catchments around Tolaga Bay.

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The forestry industry will quickly lose its social licence, and the overall benefits of forestry in minimising erosion over the full production cycle will soon be forgotten.

Previous commentators to this paper have rightly pointed to what can be achieved through forestry in terms of improved climate change resilience and mitigation, as well as biodiversity. For its part, also in June of this year, the regional council resolved to borrow some $30 million over 10 years to invest in the so-called "cloak of trees", on a target 100,000 hectares of the estimated more than 200,000ha of vulnerable steep land in our region.

A report received by the council in November 2017 as a backgrounder to that proposal revealed that the finance needed to reforest all erosion prone lands in Hawke's Bay has eight zeros. The report advises that the majority of such afforestation needs to comprise permanent forest with no intent, or permission, to harvest.

The most economically viable method proposed in the report to overcome the obvious challenges inherent in that advice is said to involve aggregation of carbon credits from participating farmers, to enable single point large volume sales to large scale carbon buyers, with indigenous species planted under a nursery crop of suitable widely spaced exotic hardwoods.

This approach would seem to dovetail with calls by some for the practice of fast-growing pinus radiata commercial forestry involving clear felling and leaving the erosion prone land vulnerable, to cease.

More realistic in my view as the so-called "wall of wood" reaches maturity, would be integration of native species with more rapidly growing exotics for the next forestry cycle, matching tree species to the land resource as Ewan McGregor proposed in his opinion piece last November.

No doubt the Tolaga Bay experience is causing our commercial production forestry companies, which I believe have a genuine commitment to environmental stewardship, to seriously pause and reconsider the monocultural model of the previous or current crop rotation as they look to replant.

The planting of permanent native tree buffer areas to act as natural slash traps around the edge of forestry blocks is presumably being considered.

The new National Standard for plantation forestry set under the Resource Management Act will also have a significant role to play in this future for the forestry sector. The law no longer permits the planting, replanting or harvesting of commercial forests on "red zone" areas of very high erosion susceptibility, without resource consent approval.

New nationwide setback controls are imposed for forestry activities alongside perennial rivers, tailored forestry harvest plans need to be submitted to the local council before harvesting commences, and slash must be left outside of areas prone to flooding.

These measures will need time to prove their worth, and we cannot simply abandon commercial forestry meantime.

This industry underpins a major part of the region's rural economy, which will ultimately deliver the revenue needed to repay the council's proposed $30m borrowing. Where also would the 100 per cent council owned Napier Port be without the throughput volume of logs now hitting record levels?

It is in this context that the council's "cloak of trees" objective sits. As with the Government's ambitious 1 billion trees programme, the council's proposed afforestation scheme remains light on detail, at least at this stage.

Many questions remain. How will the council incentivise (or direct) land use conversion over the vast areas of privately owned land involved? Where will the seedlings come from? Who will plant the trees and tend to their husbandry, management and pruning? Who will train these people?

What is the most sensible mix of exotic and native species? How do you best harness returns from carbon credits and honey production to gain the maximum return for native forest plantings?

In my view, we need to think carefully about the best structure or vehicle for combining and making the necessary council, Government and private investment required. We need to consider the role of iwi, not least as a key land-owning stakeholder in the post Treaty settlement era.

The council should partner with our educational institutions such as secondary schools and EIT, and again alongside iwi, to train and provide the workforce needed for all of this. It should also engage with the commercial forestry companies to ensure an overall integrated response, across land categories, species selection, workforce requirements and harvesting cycles.

Also, it does seem a pity to me that the council's primary investment vehicle, HBRIC, has been so significantly retrenched with the loss of a wealth of commercial and primary industry business acumen, which could surely have been employed to useful effect in working through and advising the council around this range of issues.

Maybe it is time to breathe new life into HBRIC for this purpose. The scale of the challenge is massive, as are the potential benefits, while the status quo alternative is clearly untenable. We need to put the trees cleared by previous generations back. The question I have is, are we up for it?

• Martin Williams is a barrister specialising in local government and resource management law, based in Napier.