Soil erosion has been a major issue over much of the New Zealand land surface since land clearance began. By the 1930s flooding and soil erosion were such a concern that in 1941 the Soil Conservation and Rivers Control Act was passed. This established Catchment Boards whose function was to reduce the extent and risk of soil erosion and flooding. These boards were serviced by the Public Works Department, followed by Ministry of Works and Development which managed the applied research needs through research farms and demonstration farms.
An initial government requirement was that erosion control plant material to stabilise pastoral land had to be grown in the presence of the grazing animal. Hence material that grew from poles was preferred over seedlings. An international review identified poplars and willows as those tree species most suited to the task. Tree selection began in the 1950s when Mr C van Kraayenoord undertook a nation wide poplar and willow survey and began an introduction and selection programme which resulted in the release of superior clones. Improved nursery management techniques were developed which enabled these materials to be rapidly bulked up and distributed to farmers. (This international breeding and selection has continued in a more limited capacity to the present day to keep ahead of pests and diseases and to provide clones that will prosper in specific difficult environments.)
In 1968 the National Plant Materials Centre (NPMC) was established at Aokautere, near Palmerston North, to centralise the national breeding and selection programmes. In 1975 this centre was incorporated into the Aokautere Science Centre, which was tasked with researching applied soil conservation management techniques nationally. In 1988 the NPMC had an annual budget of $2.2m of which approximately $700,000 was allocated to poplar and willow breeding.
The research for suitable plant species included native plants but none of these could be grown from poles, had similar growth rates and could grow in the presence of the grazing animal. Native plants were suited to retirement areas. The Plant Materials Handbook, 1986, Volumes 1-3 (Water & Soil Miscellaneous Publication Numbers 93-95) detailed in excess of 200 introduced plants that were suitable for erosion control in various situations, of which poplars and willows proved to be the most versatile.
In 1992 with the creation of the Crown Research Institutes, the National Plant Materials Centre was disestablished and the erosion control breeding programmes for poplars and willows transferred to the HortResearch Crown Research Institute (CRI), Palmerston North. Due to the applied nature of the research the essential breeding and trialling programmes were not able to secure long term funding. The result was a discarding of all except the basic poplar and willow breeding programmes and the maintenance of the poplar and willow gene pool (which had been built up over the preceding 40 years). ‘Survival’ funding was provided by a group of Regional and Unitary Councils (~$50,000 pa), slivers of FRST funding associated with related projects, and by the goodwill of the host CRI. All parties recognised the need for continued development of poplars and willows but it was not the core business of any research organisation. Long standing scientists and technicians employed in the programme departed in the period 1992-97.
Coupled with the decline in funding for research was a reduction in conservation plantings. It is difficult to find substantial plantings of poplars and willows on pastoral hill country dating from the 1990s, though these are present from the period 1970-90. However, heavy storm events continued to plague pastoral hill country, where ~700,000 ha remain unprotected by conservation trees. In 2007 the Ministry of Agriculture and Forestry (MAF) established a Hill Country Erosion Fund which sought to decrease pastoral hill country erosion through financial support for regional soil conservation projects. New plantings of poplars and willows are a key component of these projects
In February 2008, $450,000 per annum was sought from the MAF Hill Country Erosion Fund (HCEF) to develop new poplar and willow material, field check its suitability, bulk up supplies for Council nurseries, carry out disease and pest monitoring, research new clone physiology and to provide educational material and services. In July 2008, MAF agreed to provide $175,000 per annum for four years from their HCEF. This was conditional on Councils providing a similar amount and a stable funding source being established to provide a secure long term future. Councils agreed to the proposal and a committee was formed to establish a Poplar and Willow Research Trust by 2012 with the brief to find and secure funding for poplar and willow research beyond 2012.