Case Study

Understanding New Zealand’s native plant capacity will get us to one billion trees

When the New Zealand government announced that one billion trees would be planted by 2028, the nursery sector did not have an accurate measure of how many trees could be produced to meet this need each year.


New Zealand Plant Producers Incorporated (NZPPI) is an industry body for plant producers and industry partners which aims to advocate for plant growers and their communities. NZPPI took it upon themselves to answer this question, and enlisted Harmonic for technical support. This project allowed us to design and run a survey in addition to our core offerings of making sense of large data sets, building databases to preserve data, and visualising results.

The Challenge

Meeting the New Zealand government's one billion trees goal by 2028 requires putting trees in the ground; roughly two hundred and seventy thousand trees every day. However, the number of nurseries producing native plants in New Zealand was unknown, nor was the actual number of native and non-native seedlings produced each year. NZPPI wanted a solution that dealt with this ambiguity, accurately estimate these figures, in addition to gathering information on New Zealand’s nurseries generally.

The Solution

First, the NZPPI team worked with Harmonic to design a survey that met their needs - to gather information on New Zealand nurseries, including current and potential plant production, staffing and staff education details. To form a list of potential respondents, Harmonic used R packages to web-scrape several websites to obtain business and contact information on New Zealand’s nurseries as well as using data held by NZPPI. The survey was sent to several hundred potential respondents through email, and Harmonic followed up with those who had not responded to ensure high response rates.

As responses were not returned from all of the nurseries, Harmonic applied adjustments and imputations to the data in accordance with best practice and stored the data in a database for future use. Harmonic then analysed and visualised the data for NZPPI to use in their final report.

The Result

  • At the project’s end, NZPPI had both the data and insights about the state of nurseries to better advocate for its members and their needs, which they have summarised into a report.
  • Summary statistics, graphs, and a summary report on New Zealand’s native plant producing nurseries, and their capacity, including; actual and potential plant production, average business size, geographic distribution, and staff education.
  • Preservation of data for posterity and future comparative analysis.

The native nursery survey was the first ever national survey of native plant production in NZ. Understanding the capacity of native plant nurseries will enable us to plan for the rapid expansion of the sector to meet the demand for seedlings from the one billion trees programme.

Working with the team at Harmonic Analytics has provided us with valuable insights about what will drive this growth and what could get in the way.

We have had a fantastic response to the report from both Govt and the industry.

— Matthew Dolan, CEO, NZPPI