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TRIAL RESULTS: SPECIES PRODUCTIVITY and ADAPTABILITY

In 2021-22, full analyses of NZDFI's demonstration trials planted between 2011 - 2014 and in 2018 were completed. We now have the first detailed site/species analyses that the trials were established to produce.

Two reports are available:

The reports provide provide a comprehensive assessment of relative survival and growth rates of different species.

They also provide information about:

  • where and how the trials were established
  • the seed/genetic sources of trees planted
  • the measurement programme since establishment.

Permanent Sample Plot measurements

One of the fundamental elements of a breeding programme is to establish and regularly measure permanent sample plots (PSPs) within trial plantings. NZDFI has over 600 PSPs throughout its trial network. Measuring PSPs regularly is essential to collect robust data describing tree survival, growth, health, stem form and any other important characteristics.

More information about NZDFI's PSP network

The number of species planted each year and at each site is variable and so the number of PSPs measured by species in this analysis varied. We have combined data using statistical techniques to calculate productivity indices.

Summary: key findings

A key finding from all the demonstration trials is that there are site-specific requirements for each species to achieve optimal growth. Forest growers can use knowledge of these differences to select species to match sites, or at least to plant on sites where any given species should not be affected by adverse climatic or environmental factors.

 

A table summarising geographic and environmental details of the 2011-2018 trial sites is available (see right). Growers can review site factors and relate to their own sites, and then look at how well different species have performed on sites similiar to their own.

Follow this link for a map and details of our demonstration trial site network.

Full details of the trial sites, including notes on site preparation, silviculture and any notable adverse events that may have impacted the trial, are available in the SWP-T164 report, Appendix 2.

 

Trial sites - summary of locations and physical characteristics (click to enlarge).

Key results: 2011-2014 trials

The trial analysis evaluates tree survival, growth and stem form of eleven durable eucalypt species.

Survival of different species on different sites

An analysis of mean species survival on eleven sites planted in 2011 showed variation between sites and species. Poor survival was predominantly caused by frost and/or poor soil drainage. Other contributing factors were weed competition and browsing pest animals (goats and deer).

Species survival - trials planted in 2011.

Follow the links below to see details of how different species performed across our 2011-2014 trial series

  1. Class 1 Brown Heartwood Species - E. bosistoana, E. cladocalyx, E. quadrangulata
  2. Class 2 and 3 Brown Heartwood Species - E. eugenioides, E. globoidea, E. macrorhyncha
  3. Class 1 and 2 Red Heartwood Species - E. argophloia, E. cameldulensis, E. longifolia, E. notablilis, E.tricarpa

Early results: 2018 trial series

Eight further demonstration trials were planted in 2018, thanks to funding from the Specialty Wood Products Research Partnership (SWP).

Six species were included, all of which had been planted in earlier trials. We selected species and genotypes carefully, based on learnings from our 2011-2014 trials.

The four main species planted were:

  • E. bosistoana           Coast grey box
  • E. globoidea             White stringybark
  • E. macrorhyncha    Red stringybark
  • E. quadrangulata    White topped box

Plantings were seedling plants of all four species and clonal plants of E. bosistoana.

In addition, two other class 1 durable species were planted in some trials:

  • E. cladocalyx            Sugar gum
  • E. tricarpa                 Red ironbark

Trial sites planted in 2018.

The trials were assessed for survival at 12 months and for growth between the ages of 2.8 years and 4.8 years. The report below presents results from these assessments.

Overall, the growth measurements show that significant improvements in mean top height/mean annual increment (MTHMAI) have been achieved through selection and site-species matching compared to the 2011-2014 trials.

Eucalyptus globoidea has performed consistently well across a range of the 2018 sites, with some exceptionally high growth rates on more temperate sites seen in seedlings selected from NZDFI’s Waikakaho seedling seed stand. In addition, selected E. bosistoana, E. macrorhyncha and E. quadrangulata are all exhibiting significantly improved growth rates in the 2018 trials compared with the 2011-2014 series.