Ohariu - Past, Present, and Future

How the forests have changed through time

Pre-human times

Before human settlement most of the wider Wellington region was covered in dense native forest. The map shows the historic extent of terrestrial ecosystems. It classifies terrestrial ecosystems based on macroclimatic variables (temperature, moisture, and lithology) and edaphic extremes (e.g., extreme heat, frequent water disturbance etc). Wellington city and the surrounding landscape was dominated by two forest ecosystems.

The first was kohekohe-tawa forest which dominated the coastal lower hillsides of the Wellington Peninsula. This forest ecosystem is classed regionally endangered with only 16% forest cover remaining compared to historic forest extent. Remnants can be found in Ōtari-Wilton's Bush.

Kohekohe and tawa form a dense canopy which results in a heavily shaded understorey with an abundance of nikau and supplejack. Kawakawa, mahoe, and porokaiwhiri are commonly found in the sub-canopy. Native birds, especially kereru and tui, are important for pollination and seed dispersal for many of the canopy and sub-canopy species.

The second was tawa, kamahi, podocarp forest. On the Wellington Peninsula it was found at higher altitudes or further inland than the kohekohe-tawa forest. With only 22% forest cover remaining it is also classed as regionally endangered.

Tawa and kamahi dominate the canopy while tree ferns, rewarewa, miro, and hinau are found in the sub-canopy and understorey. Moist gully sites are often occupied by rimu, pukatea, and kahikatea.


Early European settlement

Topographic map surveyed drawn in 1916 showing how little native vegetation remains

Access was an issue for the first settlers to Ohariu Valley. The Old Road seen on the 1916 topographic map was the original road into and out of the valley.

"Ohariu is situated about six miles from Wellington, and immediately in the rear of the Town. The road to the village is over a mountain, is difficult and available only as a footpath, principally through bush." Wellington Independent, 31 August 1850.

The road that connects Ohariu Valley and Johnsonville was built in 1858. This provided easier access and opened up the valley to further settlement. An article from 1858 states the importance of access to development.

"Perhaps no stronger evidence of the value of roads, and of the utter worthlessness of the finest land until it is made accessible, could be adduced, than is afforded in the case of the Ohariu district. A valley almost equal in extent and in the fertility of its soil to the Hutt, at the same distance to Wellington, remains waste and unoccupied for some 17 years." Wellington Independent, 20 March 1858.

Aerial imagery from 1956 shows the Victoria University planting site at 268 Ohariu Valley Road and the surrounding pasture

The arrival of European settlers signalled a rapid decline in forest cover across the region. Trees were logged for timber and land was cleared for agriculture.

The first settlers arrived in Johnsonville and Ohariu Valley around the 1850s. Within 40 years of European settlement almost all native forest had disappeared in the area.

"To-day the rolling uplands and downs that stretch from Porirua down to Makara, and from the Ohariu beach to the Kaukau and Johnsonville show scarcely a single native tree." New Zealand Mail, 14 December 1904.


Present times

Increasing awareness of the consequences of deforestation has led to the creation of a large number of parks and reserves in and around the city.

The Outer Green Belt is a network of reserves managed by the Wellington City Council and runs from Porirua City in the north all the way to the southern coastline.

In 2018 Wellington City Council acquired 31 ha of land at 268 Ohariu Valley Road as part of the Outer Green Belt.

Of that land 11 ha was leased to Victoria University of Wellington as part of the University's Zero Carbon Plan.

The land is leased to the university for 33 years during which time the university is responsible for planting. The carbon credits will be split evenly between the university and the council.

The current plan is to plant 23,000 trees over the next 3 years with volunteers planting around 2,400 trees per year. Groundtruth have been contracted to plant the remaining trees.

The planned planting areas are shown on the map. There are some restrictions on planting areas and heights due to power lines and a cell tower. The remaining areas already have native vegetation.


The Future Vision

There are multiple outcomes expected from the reforestation of this site. The main one which both the university and the council have in common is restoring indigenous biodiversity.

Victoria University expected outcomes

2021 planting at 268 Ohariu Valley Road

  • Carbon sequestration
  • Providing opportunities for students, staff, and alumni to plant trees
  • Engaging with the city, both council and public
  • Provide teaching and research opportunities

Wellington City Council expected outcomes

  • Providing local communities access to extensive open areas characteristic of the Outer Green Belt
  • Extension of the Outer Green Belt ecological corridor
  • Local community engagement

Find out more about the benefits of reforestation...

Species (in this case birds) can fly to connecting reserves and onto the wider Wellington region

What is an ecological corridor?

An ecological corridor connects two significant ecological areas together. It allows species to move from one area to another allowing greater species and genetic diversity.

It is important to preserve species and genetic diversity as it allows species to survive and recover in the event of disasters, diseases, or pest infestations.

The Outer Green Belt will in the future act as an ecological corridor for many species.

What is carbon sequestration?

Carbon sequestration is the process of capturing carbon dioxide from the atmosphere and storing it. In this case the trees take up carbon dioxide as they grow and convert it into biomass, meaning they store it within themselves.

As a forest grows it will store more carbon until it reaches equilibrium. Once a forest matures natural thinning and decay mean that the amount of carbon a forest absorbs and releases is equal.

Historic forest extent map

DOC - Singers Forest Classification

Forest classification

GWRC - Forest Ecosystems of the Wellington Region

Newspaper quotes

Papers Past

1916 Topographic map

Sourced from LINZ. Crown Copyright reserved

Outer Green Belt

WCC - Outer Green Belt Management Plan

Topographic map surveyed drawn in 1916 showing how little native vegetation remains

Aerial imagery from 1956 shows the Victoria University planting site at 268 Ohariu Valley Road and the surrounding pasture

2021 planting at 268 Ohariu Valley Road

Species (in this case birds) can fly to connecting reserves and onto the wider Wellington region