The Port Hills (Te Poho-o-Tamatea) are of special significance for their environmental, geological and scenic values. They are also of national and international interest for their geological features.

Overview

The Port Hills are a 12 million-year-old remnant of the Lyttelton volcano crater. Wind, rain, sun, ice and snow have eroded the crater over the last 8 million years, to what can be seen today. For visitors and residents alike, the rugged outcrops of the Port Hills against the skyline, in contrast to the flatness of the Canterbury Plains, are a memorable sight.

Visible from well beyond Christchurch, the Port Hills [PDF, 668 KB] [PDF 670KB] are an obvious feature forming a backdrop to the city. The majority of the Port Hills consists of a rocky open tussock landscape which has a high proportion of indigenous plant species and which provides an almost 'wilderness experience' in close proximity to the major urban area. 

Value

Considered an outstanding natural feature and landscape of national importance, there are a number of internationally significant geological features, including prominent rock outcrops and a number of volcanic dykes, within them. The area is also important in terms of scenic value for residents and visitors to Christchurch, with road access along the Summit Road, walkway networks and through the operation of Mt Cavendish gondola.

Generally the qualities and attributes of the Port Hills that make them special to us can be classified into six broad areas:

Area Details
Environmental
  • Geological formations; examples of these include Castle Rock and the Multiple Dykes.
  • Tussock grasslands; these cover large areas facing the city tending to be denser at higher altitudes and south-facing slopes.
  • Forest cover; native forest on the Port Hills varies from small remnant patches of ancient podocarp forest with large totara, matai and kahikatea to large areas of regenerating second growth forest. Most of the native forest is located between Rapaki Bay and Gebbies Pass on both sides of the Hills.
  • Native Birds; many of the native birds visiting city gardens in the winter come from the Port Hills forest areas.
  • Invertebrates; a large range of native insects still occupy the Port Hills forest areas.
  • Lizards; there are at least three species of native lizards, including the attractive jewelled gecko on the Port Hills.
Landscape

The landscape qualities of the Port Hills provide a distinctive backdrop to the City, harbour and low plains. The main features of this landscape are:

  • The rolling tussock grasslands, largely unobstructed and uninterrupted by structures, which form a unique backdrop to Christchurch.
  • The steep slopes, bluffs and rock cliffs of the Harbour Basin with a patchwork of agricultural and natural bush elements.
  • The rolling pastoral hill slopes and regenerating bush areas of the southwestern Port Hills from Hoon Hay valley to Gebbies Pass.
  • The Port Hills skyline with rolling slopes punctuated by volcanic tors and high bouldery peaks.
History The Port Hills have a rich and varied Māori and European history. The recent biological history stretches back to the last ice age approximately 14,000 years ago.
Scientific and educational The Port Hills have important scientific value especially in the area of ecological research. They are one of the most intensively studied areas in the world in terms of volcanism. Structures such as Castle Rock and the Multiple Dykes are world-class examples of their feature type.
Tourism The Port Hills are an important ingredient in the tourist experience of Christchurch, and thus have economic value to the city. Taking visitors for a trip along the Summit Road is standard practice for many residents. The closeness of such a landscape to a major urban area is unique.
Recreation The Hills offer a wide range of recreational opportunities close to the city including walking, tramping, running, mountain biking, paraponting and rock climbing.

Planning issues

There are a number of issues surrounding the use of the Port Hills.

Urban encroachment

Many people value the Port Hills for their open rugged beauty. The building of houses changes this, and in some people's minds adversely affects it as the 'natural' feel is lost and replaced with a human dominated landscape. Many people however wish to live on the Hills for the views and to be above the smog layer.

Changes in farming practices

As the economic fortunes of sheep and cattle farming have declined, so has the viability of pastoral farming on the Port Hills. For some, farming is simply uneconomic and farmers have sought ways to get a better income from their land. One of these is the introduction of exotic forest. Trees grow reasonably well on the hills, especially the upper slopes and western parts where the rainfall is higher. But again the trees have the potential to change the existing character of the Port Hills, from one of an open tussocky landscape to that cloaked in dark green forest.

Biological

The Port Hills have undergone some rapid and marked changes over the last 1000 years, from being covered primarily in native forest and shrubland to that which is there today. All this change has meant much stress for the remnants of the indigenous plant and animal life. Present threats include possums, goats, rabbits, stoats, and weeds such as the South African boneseed bush.

Erosion

Parts of the Port Hills are susceptible to erosion which endangers lives, reduces pasture areas, causes unsightly scars and contributes to problems with stormwater drainage and siltation of waterways.

Recreation

As the Port Hills are so close to a major urban area, a large percentage of people wish to use them. Conflicts in use can arise for example between mountain bikers and walkers and trampers.

Urbanisation: A case study

Urban encroachment onto the Port Hills has often been a topical issue. As pastoral farming has become economically marginal on the Port Hills, some landowners have sought other ways to realise income from their land. One of these has been to subdivide for housing. The increases in value can be enormous, from $5000 a hectare at rural rates to $100,000 a section (600m2).

Conversely, many people value the Port Hills for their unaltered natural state and are very much opposed to further development. This can pose a dilemma for the Council, often trying to find the middle ground through compromise, which means some development may be permissible, provided the Council, i.e. the people of Christchurch, are compensated in some way for loss of natural values. This could mean that Council approves development of some land in exchange for high value private land becoming available for public use. This is one example of how the resource is managed, which leads us to the next section, Management of the Port Hills.

Management

Council

Management of the use of the Port Hills is primarily through the Resource Management Act (1991). The RMA charges District/City Councils with managing the use, development and protection of land; this management is essentially carried out through The City Plan and this states the way in which land can be managed. Management of the use of the Port Hills can be carried out in a number of ways, including purchasing of land for reserves, provision of works and services and provision of information.

The main way management is undertaken is through the RMA and rules in the plan. These rules seek to allow people to use the Port Hills for whatever purpose, while ensuring that the potential of the resource is sustained for future generations, the life supporting capacity of water, soil and ecosystems is safeguarded, and any adverse effects are avoided or mitigated, (s. 5 RMA). It is all about balance, and this is the challenge set down by the RMA, to 'sustainably manage' our natural and physical resources.

Other organisations

Various other organisations have some kind of interest in the Port Hills including the Department of Conservation, Ngai Tahu, the Summit Road Protection Society, Environment Canterbury and Selwyn District Council.

The Summit Road Protection Authority administers the Summit Road (Canterbury) Protection Act 2001, which specifically controls land use on the upper slopes to ensure unobstructed views from the Summit Road are maintained. This legislation is unique among NZ legislation and shows the high regard parliament holds for the skyline of the Port Hills.

Additional information sources
  • Residents Associations
  • Victoria Park Interpretation Centre
  • Development Consultancies, e.g. Davis Ogilvie, Boffa Miskell

Relevant information such as committee reports and newspaper articles can be sourced from the Aotearoa New Zealand Centre at the Central City Library(external link), 89 Gloucester Street, Christchurch.

Residents’ Associations, another useful source, may also be found on the Christchurch City Libraries’ community information database - CINCH database(external link).

Librarians at the Central City Library are available to assist with research projects.