Judy Gill: When Tree Removal Becomes Risk

Hawke’s Bay, Mauao, and the Consequences of Substituting Ideology for Environmental Science

Introduction

Natural disasters do not begin with storms alone.

They begin with decisions made years earlier — decisions about land use, vegetation, risk tolerance, and which knowledge systems are permitted to guide public policy.

Recent events in Hawke’s Bay and at Mauao (Mount Maunganui) provide two geographically distinct but structurally similar case studies. In both, the removal of mature trees under policy-driven restoration frameworks preceded severe physical damage when extreme weather occurred. In both cases, councils acted within documented governance structures that prioritised mātauranga Māori–based policy frameworks over established environmental science.

The outcomes were not symbolic. They were physical, measurable, and destructive.

Hawke’s Bay: Tukituki River and Cyclone Gabrielle

In mid-February 2023 (13–14 February), Cyclone Gabrielle caused widespread flooding across Hawke’s Bay. Rivers overtopped stopbanks, floodplains were inundated, and large volumes of debris were mobilised downstream [1–3].

Along the Tukituki River, behind the stopbank, approximately twenty large, mature poplar trees had stood for decades. These trees were healthy and well established. They provided shade for neighbouring paddocks and river users and, critically, their deep root systems contributed to bank stability and resistance to flood forces.

Several years prior to Cyclone Gabrielle, the local council removed these poplars. They were replaced with newly planted native trees. While ecologically well-intentioned, these replacements were young, shallow-rooted, and incapable of performing the same stabilising function in the short to medium term.

When the river flooded during Gabrielle, the remaining poplar stumps and large woody debris lying between the riverbank and the stopbank were mobilised by fast-moving floodwaters. This mass of debris was swept downstream and driven directly into Lindisfarne Bush, a significant area of established native vegetation.

The consequences were severe:

very old native trees were destroyed

the parking area was wiped out

the toilet block was destroyed

The damage was not caused by the poplars while they were standing and functioning. It occurred after their removal, when destabilised debris was free to move under flood conditions.

This account is drawn from a firsthand record by Irene van Egten, a primary school teacher and resident of Hawke’s Bay, posted on social media on 24 January 2026.

Mauao (Mount Maunganui): Landslides and Governance Context

In January 2026, significant landslides occurred at Mauao (Mount Maunganui), prompting renewed public concern about land stability and vegetation management on the maunga.

The governance context is not disputed and is well documented.

Ownership of Mauao was returned to iwi in 2007. The reserve is jointly managed by Tauranga City Council and the Mauao Trust, representing Ngāi Te Rangi, Ngāti Ranginui, Ngāti Pūkenga, and Waitaha [4–6].

Waitaha and Mauao

Waitaha are included in contemporary Mauao governance documentation as part of modern Treaty-era settlement and reconciliation processes. Their inclusion does not imply historical occupation, control, or sustained settlement of Mauao.

In the Tauranga Moana region, archaeological evidence, pā sites, cultivation areas, and burial grounds associated with Mauao are most consistently linked to Ngāti Ranginui, Ngāi Te Rangi, and Ngāti Pūkenga. Waitaha are more commonly associated with early South Island traditions, and there is no established archaeological record demonstrating a distinct or dominant Waitaha presence at Mount Maunganui. Their appearance in present-day governance arrangements reflects whakapapa recognition within contemporary frameworks rather than new historical evidence of occupation.

The Mauao Historic Reserve Management Plan (2018) mandates the progressive removal of exotic (non-native) trees, including large, well-established specimens. The plan explicitly prioritises iwi-led ecological restoration, removal of exotic trees from culturally and archaeologically significant sites, replacement with native vegetation (“restoring the Cloak of Mauao”), and the incorporation of mātauranga Māori into land-management decisions [4].

Council records confirm that since 2018, numerous large exotic trees have been removed, including pine, macrocarpa, poplar, and oak. Removals have involved ground crews and helicopter operations and have occurred near steep slopes and archaeological terraces [4–5].

Whether the January 2026 slips are primarily geotechnical, climatic, or management-related requires formal investigation. However, the policy framework under which large-scale tree removal occurred is clear, documented, and publicly available.

The Common Issue

These two cases are not identical in terrain or mechanism, but they share a critical feature.

In both Hawke’s Bay and at Mauao, land-management decisions prioritised ideological restoration frameworks over established environmental science.

Specifically, decision-making displaced consideration of:

the stabilising role of mature trees

the decades required for replacement vegetation to perform equivalent functions

the physical realities of floodplains, slope stability, debris mass, and water velocity

The outcomes were governed not by narrative or intention, but by water, gravity, debris, and soil failure.

Environmental science exists precisely to model these forces — through hydrology, geomorphology, geotechnical engineering, and risk assessment. When those disciplines are subordinated to policy frameworks that do not operate on the same evidentiary basis, predictable consequences follow.

Conclusion

This is not a debate about culture, identity, or symbolism.

It is a question of standards.

Environmental decisions that affect public safety, infrastructure, and ecosystems require environmental science. Cultural or ideological frameworks — whatever their value in other contexts — are not substitutes for scientific risk modelling.

The remaining question is not about intent.

It is about cost.

At whose price?

References

Cyclone Gabrielle – Hawke’s Bay

[1] RNZ — Cyclone Gabrielle coverage (Hawke’s Bay flooding)
https://www.rnz.co.nz/tags/cyclone%20gabrielle

[2] Hawke’s Bay Regional Council — Cyclone Gabrielle response and river flooding
https://www.hbrc.govt.nz/our-council/cyclone-gabrielle-response/

[3] NIWA — Cyclone Gabrielle: weather and flooding analysis
https://niwa.co.nz/weather/cyclone-gabrielle

Mauao (Mount Maunganui)

[4] Tauranga City Council — Mauao Historic Reserve Management Plan (2018)
https://www.tauranga.govt.nz/Portals/0/data/council/plans/files/mauao-reserve-management.pdf

[5] Tauranga City Council — Mauao Trust governance and implementation material

(Referenced for tree removal methods and management practice.)

[6] New Zealand Parliament — Mauao Historic Reserve Vesting Act 2008
https://www.legislation.govt.nz/act/public/2008/0031/latest/DLM1037757.html

Judy Gill BSc, DipTchg, is a parent, former teacher, and a staunch advocate for secular education.