THE 1997 BANKS MEMORIAL LECTURE
History and Management of Riccarton Bush

Reproduced from an article by Brian Molloy

From The New Zealand Garden Journal (Journal of the Royal New Zealand Institute of Horticulture), Vol. 3, No. 1, October 2000, pp. 13-18.

Riccarton Bush, in the heart of the city of Christchurch, is arguably one of the oldest and best documented protected natural areas in the country (Fig. 1). That this 7.8 ha remnant of kahikatea floodplain forest has survived natural catastrophes and the impact of two human cultures is extraordinary to say the least. It has done so largely by a combination of its own intrinsic qualities and the foresight and dedication of committed people, beginning with the Scottish settlers William (1816-1851) and John (1820-1854) Deans in 1843.

Today, Riccarton Bush stands as a constant reminder of the city's natural and cultural history, a living museum of native plants and animals, a storehouse of information on forest management, both good and bad, and an example of documentation by natural historians and others. Much of this information is captured in the book Riccarton Bush: Putaringamotu published by the Riccarton Bush Trust in 1995 (Molloy 1995). Here I want to focus on the management and sustainability of Riccarton Bush, but first a few historical and biological tidbits taken from the book to set the scene.

Some historical facts about Riccarton Bush

• Prior to European settlement of Christchurch (Otautahi), the Riccarton Bush area (Putaringamotu) was occupied by Ngai Tuahuriri, an influential sub-tribe of Ngai Tahu with headquarters at the famous pa of Kaiapoi.
  
• Putaringamotu was one of a number of ridges or wakawaka in the vast swampy area of Otautahi, occupied by the whanau who had the tribal authority to live there.
• 1836 — First recorded European sighting of Riccarton Bush by Captain William Rhodes of the barque Australian.
• 1840-41 — First attempt to settle near Riccarton Bush by James Herriot and party.
• 1843 — William and John Deans settle at Riccarton Bush with the permission of the Maori owners, signing a formal lease agreement in 1846.
• 1844 — First sketch of Riccarton Bush and the Deans' farm by John Barnicoat, followed by the first map of the same in 1845 by Charles Meryon of the French corvette Rhin.
• 1848 — Putaringamotu passed from Maori ownership to the Crown by virtue of Kemp's Purchase, and later that year the Deans' brothers were granted 400 acres there, including Riccarton Bush, but the timber on one half to be the property of the New Zealand Company.
• 1849 — First survey map of the Deans' farm and Riccarton Bush drawn by Charles Torlesse, followed by the first photograph taken in 1860 by the celebrated Dr. Alfred Barker, and the first published list of plants of Riccarton Bush by John Armstrong in 1870.
• 1914 — Riccarton Bush (6.4 ha) gifted to the people of Canterbury by the Deans' family, and the Riccarton Bush Act passed incorporating a Board of Trustees and setting out their responsibilities and the conditions of the Deans' family gift.
• 1947 — Riccarton House and grounds (4 ha) and the remaining 1.4 ha of Riccarton Bush added to the reserve by purchase, followed in 1975 by the purchase of the historic site of the Deans' original houses and other buildings (3 roods 12 perches).
• 1989 — Amalgamation of Christchurch local authorities ushering in a new era of funding and administration of the Riccarton Bush reserve by the Board of trustees.

Some biological features of interest

• Riccarton Bush is the last in line of similar forests that occupied the site of Christchurch over hundreds of thousands of years between successive ice ages. The remains of these ancient forests lie buried beneath the city between layers of glacial outwash and alluvium like a giant club sandwich.
• Over the last 15,000 years, fires, floods and changing sea level were major factors in the history of the vegetation of Christchurch. The last major flood of the Waimakariri River to affect the site of Riccarton Bush occurred about 3,000 years ago, and the last major fire to affect the Bush, presumably lit by the Maori occupants, occurred about 240 years ago. By the 1840s Riccarton Bush covered a mere 22 ha, largely as a result of periodic fires.
• Kahikatea is the dominant tree of Riccarton Bush, and at the last census (1978), 478 adult trees were counted, with a mean height of 25 m, a mean diameter of 58 cm, and a maximum-recorded age of 550 years, although some of the larger specimens may be older (Fig. 2).
• Kahikatea trees are wholly male or wholly female throughout their life. In Riccarton Bush the ratio of males to females is 1:1, the sexes are evenly dispersed, and male trees are larger than females.
• At the last census (1993), 71 species of native trees, shrubs, lianes, and herbs were recorded from Riccarton Bush compared to 73 in 1870. There is also a good representation of ferns, mosses, liverworts, lichens and fungi.
• Riccarton Bush is the southern limit in eastern South Island of hinau, and along with Banks Peninsula, the southern limit of titoki and the native passion vine or kohia.
• Lying within the "Garden City", Riccarton Bush is open to constant invasion by introduced plants, some recorded here as naturalised plants for the first time in New Zealand. At the last census (1994), 188 species were listed; more than twice the number of native species, although most occur in very low numbers.
• About 300 species of moths and butterflies have been collected from Riccarton Bush between 1859 and 1996, and the Bush is the type locality for several genera and species. The Bush also has a rich scale insect fauna and still harbours a few geckos.
• Between them John Deans and Charlotte Godley, who lived alongside the Bush, recorded the following native birds in the 1850s: kaka, kereru, tui, bellbird, South Island robin and kakariki. Today the kereru, fantail, warbler and white-eye are the hardy survivors.

Survival and protection of Riccarton Bush

When the Canterbury Pilgrims arrived in December 1850, Riccarton Bush and four similar patches at Papanui, Woodend, Kaiapoi and Rangiora were the sole survivors of a former widespread forest reduced by floods and Maori fires. By July 1851 that part of Riccarton Bush available to the Pilgrims by agreement had been cut down, and by the early 1860s little remained of the other remnants.

From the beginning, the Deans' brothers used the timber resources of Riccarton Bush judiciously. When William died in 1851 the responsibility for safeguarding the Bush fell upon his younger brother John, and when he died in 1854 the stewardship passed to his young wife Jane. On his deathbed, John expressed the wish that every effort should be made to preserve the Bush from destruction. That Jane carried out this wish implicitly is now well documented, and we owe this somewhat frail but determined woman our deep gratitude (Fig. 3).

Some doubt has been raised over the motives of the Deans' brothers in retaining the Bush. As both have been dead now for almost 150 years, we can never know their personal motives. But let Jane speak for the brothers on this matter (Deans 1882):

"The remaining part of the Bush has been preserved as well as possible, in accordance with the late John Deans' wishes, no timber being now cut up except fallen timber, which is used for fencing purposes, the aim being to preserve the Bush as long as possible; it has been planted round and throughout with forest trees wherever timber has been cut for building purposes, the gaps being filled with oaks, ashes, elms and gums, etc, as the soil appeared suitable for one or the other. This was done before Sir J. Vogel enunciated his "Native Forest Preservation' scheme." (italics mine)

There is no doubt in my mind that conservation was the real motive behind John Deans' wish, and in this he showed remarkable foresight. The same motive was undoubtedly behind the purchase of 40 acres of untouched bush at Peel Forest, South Canterbury, in 1881 by Arthur Mills who was appalled at the wanton tree-felling there. Indeed, conservation began very early in New Zealand's history, and we should freely acknowledge that. The formal protection of Riccarton Bush in 1914 was spearheaded by prominent citizens of Christchurch, among whom Harry Ell of Summit Road fame and the eminent botanist Dr. Leonard Cockayne were foremost. Thus the deathbed wish of John Deans had finally come to pass.

Early management of Riccarton Bush

During the 70 years of occupancy by the Deans' family, certain events and decisions taken were to shape the future of the Bush. Foremost was the felling of half the Bush by the Canterbury Pilgrims by agreement — one of the country's first examples of cutting rights. This clear-felling, together with the selected removal of kahikatea, totara and matai for building purposes, created a fresh boundary to the Bush and several large canopy gaps in the interior. To help offset the exposure of the Bush to the elements and to encourage the re-growth of native species, Jane Deans arranged for introduced trees, mainly oak and ash, to be planted along the boundaries and in the internal gaps from the late 1860s onwards. As Jane Deans noted, the introduced trees did well in the Bush, but instead of protecting young native plants, they tended to smother them out by their shade and fallen leaves.

First sixty years of trust board management

• 1914 — Riccarton Bush Trust Board took over the responsibility of the Bush, appointed its first ranger and decided not to open the Bush to the public until boundary fencing was completed, gates installed, a preliminary walking track put in place, and unwanted debris cleared.
• 1917 — Riccarton Bush opened to the public on 24 February 1917 by the Governor, Lord Liverpool. That same year the first plan of the Bush showing its present and former boundaries and the initial system of walking tracks was drawn up for the public's benefit.
• In 1914, and for many years afterwards, the Bush was in a dilapidated state (Fig. 4), and where trees had been extracted the associated debris and rapid growth of smothering climbing plants required much attention. Unfortunately, the Bush was treated like an English woodland, much of the debris was gathered up and burnt on the spot, and grassy clearings and the forest floor were regularly mown to produce a 'tidy' appearance.
• Initially the Bush was bounded by farmland. From 1925 onwards, this farmland was sold and sub-divided for residential housing. Over time, gates appeared along the boundary, private tracks were formed, garden refuse was dumped in the Bush, and excess runoff water accumulated. Apart from draining the excess water, these problems remained unresolved for many years.
• When the Trust Board took over in 1914 parts of the Bush were over-run by undesirable plants such as elderberry, blackberry, sycamore and many others. Disturbed parts of the Bush provided an ideal environment for this alien flora and the control of these unwanted plants has been an ongoing but important task.
• The initial track system became a permanent feature of the Bush and required constant care and attention. Some parts were systematically built up with hardfill, which introduced drainage problems in later years.
• Exotic trees planted in the Bush interior by Jane Deans were gradually removed, and by 1952 the last of these trees were felled. Some of the rotting stumps can still be seen today. The main border of oak and ash along the Bush boundary remained intact.
• The most extensive damage to the Bush during this period occurred in July 1945 when 45 cm of snow lay upon the ground in the city and suburbs. The debris in the Bush resulting from this storm was still being cleaned up in the late 1950s.
• The introduction of native plants to the Bush was one of the most critical activities carried out in this first phase of management. Sadly, it lacked adequate guidance and documentation, with the result that species not native to the region were often planted, in many cases the sources of plants were unknown, and hybridisation occurred between resident and introduced plants. One of the more invasive species, the North Island lacebark (Hoheria sexstylosa) became firmly established, displacing many of the local native trees and hybridising with the resident narrow-leaved lacebark (Hoheria angustifolia).

The last twenty-five years

From 1974 the Trust Board adopted a fresh approach to the management of Riccarton Bush in an attempt to turn around the unnatural and damaging effects of the previous 'woodland' phase, and to address other problems. As each project was undertaken, the public was kept fully informed and their support has been consistently strong.

• The boundaries of the Bush have now been secured by new fencing, thus eliminating private gates and walking tracks and the dumping of rubbish.
• A thorough soil and groundwater survey of the Bush has been completed, and the legal boundaries re- surveyed; both essential for management purposes.
• The problem of surplus water from adjoining properties has been resolved, and the ponding effect of the network of compacted tracks corrected.
• In 1974 the Bush was grossly over-tracked to the detriment of the forest environment and public use. Many of the tracks have now been closed, parts receiving the greatest use were replaced with concrete paths to provide an all-weather surface, especially for disabled folk, and a new boardwalk was constructed through the least disturbed part of the Bush.
• From 1974 the practice of gathering up litter and burning it in the Bush was stopped and all litter, including large fallen trees, is now left to rot naturally. The resultant buildup of forest litter has had a marked beneficial effect on the flora and fauna of the forest floor especially, and the micro-environment generally.
• From 1974 the practice of mowing grass clearings and the forest floor was also stopped. This practice was responsible for eliminating native climbing plants such as the white rata and white clematis, which were never abundant, and had caused considerable damage to the butts and large surface roots of kahikatea in particular. Fortunately most of this damage has callused over, although a few trees are now suffering from advanced butt rot.
• New entrances, signs, brochures and other items of interpretive value have been put in place, and a variety of studies are encouraged and supported.
• A consistent approach to the control of troublesome weeds and pests such as "urban" possums and domestic cats has been adopted, with considerable help with weed control by local groups.
• In 1975 the felling of oaks and other introduced trees on the Bush boundary was begun, and completed in 1984. This project, not without controversy from some neighbours, was carried out in stages and the cleared areas were prepared for minimal planting, allowing the Bush to spread naturally to the boundary of the reserve in the years ahead.
• In 1975 work began on the establishment of a nursery for propagating plants from seed sourced entirely from the Bush. Over the following years numerous plants of understory trees such as karamu, ribbonwood, matipo, mapou, lemonwood and others were planted in clearings and along the boundary to provide initial shelter for naturally spreading trees to establish and to suppress the growth of grasses and other weeds.
• Initial plantings in 1975 were monitored from fixed photo points, and their subsequent growth proved to be rapid and dramatic (Fig. 5).
• More recently a large-scale project removing the North Island lacebark from the Bush has been undertaken with considerable success and with the help of local organisations and interest groups.
• It is anticipated that the practice of new planting in gaps throughout the Bush will continue for several years yet, and to this end the nursery has been re-organised to cope with the demand, and also to supply surplus plants for other projects around the city.

Conclusion

In the last 25 years Riccarton Bush has demonstrated the remarkable resilience of small forest remnants and their inherent capacity to respond to simple and sensible management practices. The lessons learned throughout the Trust Board's stewardship are now embodied in a management plan adopted in 1991 and reviewable at the Board's discretion. In my time I have been astounded by the rapidity and magnitude of the changes in Riccarton Bush in response to the management practices put in place. Substantial parts of the Bush are now difficult to distinguish from undisturbed forests elsewhere in the country. There is still a way to go before the Bush becomes completely self-sustaining, but I am confident this will happen if the present management continues. We all realise that Riccarton Bush is now completely isolated from normal processes of replenishment and the direction of change it will take will differ accordingly. Our main object is to restore the Bush to a state where natural processes can take over. Compared to its earlier open woodland condition, the Bush now has a continuous cover of woody plants, herbs and ground ferns, and in places is quite impenetrable. The dramatic increase in vegetation generally now places greater demand on soil moisture, particularly during exceptionally dry summers, and also increases the risk of fire. With this in mind, the Trust Board's next major project is to install a permanent, dual irrigation/ fire protection system as an insurance against fire, and more especially for the maintenance and enhancement of the Bush.

Over the last 25 years my association with Riccarton Bush, representing the Canterbury Branch of the Royal Society of New Zealand, has been a most fulfilling experience. I thoroughly recommend a similar commitment to forest remnants elsewhere in the country.

References

Deans, J. 1882. Canterbury past and present. New Zealand Country Journal 6 (6): 381-392.

Molloy, B. (ed) 1975. Riccarton Bush: Putaringamotu. Riccarton Bush Trust, Christchurch.

Web-notes: Other sites that feature Riccarton Bush

The article "Riccarton Bush A City Treasure" from Our Environment: Issue 25, Summer 2000 is available at the Christchurch City Council website.

Information on the Riccarton Bush Trust is available at NZERN — the New Zealand Ecological Restoration Network website.

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