Small Forest Grower Research

Forest Growers Research Annual Conference

October 17-19 2017

Topic: Small forest grower research

1.     Eucalyptus nitens breeding

2.     Performance of naturally durable eucalypt posts in Marlborough vineyards

3.     The Forecaster Calculator V1

4.     Improving small plantation and woodlot inventory

1. Eucalyptus nitens breeding

Conference presenter:  Dr Mari Suontama, Scion

Presentation: Eucalyptus nitens Breeding and Seed Orchards

In New Zealand, Eucalyptus nitens is grown mainly for pulp wood on short rotations (15-20 years). It grows very fast on the right sites, has outstanding form and is cold-tolerant. The main production area for E. nitens is Southland.

To date, genetic improvement has focused on traits for pulp wood production. The third generation of improved progeny are available.

Eucalyptus nitens is difficult to process into solid wood products because of its high levels of internal checking and shrinkage. A new initiative under the Specialty Wood Products research partnership (SWP) is therefore focusing breeding effort on traits which will enable higher value solid wood production.

New seed orchards established

Research has confirmed that important wood properties including levels of shrinkage, internal checking, stiffness, and growth strain, are all heritable, so will respond to tree improvement programmes. Two new seed orchards have been established in Southland in collaboration with an industry partner. One of these will focus on producing germplasm with lower levels of growth strain, internal checking and shrinkage; the other will provide germplasm for high-quality pulp. A third seed orchard has also been established in North Canterbury, with a focus on volume and wood density.

The business case for E. nitens improvement

There is considerable scope for the genetic improvement of E. nitens to add significant value both for growers and manufacturers of solid wood products and pulp. Laminated veneer lumber (LVL) is an important potential market for E. nitens veneer.

A strong business case has been made for genetic improvement, including the use of genomics to enable more specific traits to be isolated and incorporated into new material. It is anticipated that improved fourth generation planting stock for both enhanced solid wood production and higher quality pulp will become available for commercial planting within the next five years.

The business case for genetic and genomic improvement of E. nitens

2. Performance of naturally durable eucalypt posts in Marlborough vineyards

Conference presenter: Paul Millen, Project Manager, NZ Dryland Forests Initiative

Presentation and Video: Drylands and Vineyard Posts

Marlborough is New Zealand’s major wine-producing region, with some 66% (24,000 ha) of the total national vineyard area (36,000 ha).

An estimated 15 million posts are in use in Marlborough’s vineyards. Almost all of these are CCA-treated radiata pine posts. These posts give rise to a range of environmental concerns, both for growers and the wider public, including:

  • unacceptable under organic/sustainable wine production standards
  • brittle and easily broken by mechanical pruners and harvesters, expensive to replace
  • broken posts are hazardous and expensive to dispose of
  • potential toxic leachates from posts could have serious consequences for both soil health and the industry’s market image.

    Mechanical harvester operating in a Marlborough Vineyard.

    Broken CCA-treated posts stockpiled and awaiting disposal.

Between 2006 and 2009, Marlborough-based Vineyard Timbers Ltd sourced timber from several promising naturally durable species, including Eucalyptus bosistoana (coast grey box), and E. globoidea (white stringybark). Existing mature trees were felled and milled to produce vineyard posts.

Around 750 E. bosistoana posts, 300 E. globoidea posts, plus 355 posts of other eucalyptus species, (a total of around 1400 posts), were purchased by six vineyards in the lower Wairau Valley. The vineyard owners were keen to try an alternative to CCA-treated posts. Based on their durability ratings (Australian Standard), the E. bosistoana posts are expected to last at least 20-25 years in situ, and the E. globoidea 15-20 years.

Performance of the durable timber posts over 9-11 years

In 2017, a survey of the six vineyards where the durable vineyard posts had been installed 9-11 years ago was carried out. The survey had two aims:

  • to gauge the vineyard owners’ experience and opinion of the posts’ performance
  • to test the posts for in-ground decay, and identify reasons for breakages or other poor performance in situ.

Post performance: feedback from vineyard owners and managers

During visits to the vineyards, 1065 posts were found to still be in service. Another 14 were found broken, 1 failed from decay and 45 in storage.

Feedback about the posts was generally positive, thanks to their natural durability and hence acceptability for organic/sustainable production standards.

Breakages reported were minimal – only 14 in total. Negative comments were about how hard the eucalypt timber is, making nailing or fastening wire hangers difficult. Pre-drilling was deemed necessary. One owner also found some posts had twisted in storage due to cross grain.

Testing for decay

A sample of 150 posts in service across four vineyards were examined to assess timber condition in the top 200 mm of the soil horizon where maximum decay is likely to occur. The assessments indicated:

  • thebosistoana posts in service had very low levels of decay
  • by comparison, globoidea posts were showing higher decay rates but many are still in service and should remain so for a number of years.

Analysis at a case-study vineyard found only 8 E bosistoana posts broken out of the 265 installed 11 years ago. This equates to 3% of the total, giving an annual breakage rate of 0.3%, compared to up to 5% annual breakage in conventional CCA-treated pine posts. All but two of 50 posts assessed on the vineyard for in-ground decay showed less than 5mm of decay, even after 11 years in service.

The feedback from vineyard owners/managers and the results of our decay assessments demonstrate that durable eucalypt vineyard posts of both E. bosistoana and E. globoidea provide at least 10 years’ useful service with low levels of breakage.

   bosistoana post showing virtually no decay after 11 years in service.

Website:  New Zealand Drylands Forests Initiative

3. Forecaster Calculator

Conference presenter:  Melissa Evans, Scion

Presentation:  Forecaster Calculator

The Forecaster Calculator is an upgraded online version of the Radiata pine and Douglas-fir calculators, which were originally designed for small forest owners. The upgrade is a combined Scion and NZFOA initiative.

The new calculators are web-based, and will be free and easily accessible to users, who will simply be required to register on-line. The ‘engine’ of the calculators is Scion’s powerful Forecaster forest management software. The calculators have been designed to be easy and quick to use, and will be an excellent decision-support tool for small forest owners.

Features of the Forecaster Calculators

Features of the new Forecaster Calculators include:

  • use Forecaster’s spatial surfaces and site indices – Site Index, 300 Index and 500 Index. Users will be able to locate their own site on a map on the screen, and their site will then be correctly described in terms of the indices
  • users need only basic knowledge of existing or proposed plantation; inputs of data are easy to make
  • outputs are easy to interpret; available on-line or as pdfs. Outputs include e.g. log yield predictions for different regimes and analysis of different silvicultural options
  • updates will happen automatically, whenever Forecaster is updated
  • freely available; accessible any time on any device.

The calculators will be available via the Forest Growers Research website. They are ready for deployment, and growers will be informed as soon as they go live.

4. Improving small plantation and woodlot inventory

Conference presenter:  Jonathan Dash, Scion

Presentation:  Improving Small Plantation and Woodlot Inventory

This project is exploring ways of using emerging technology in a cost-effective way for small forest inventory. Accurate inventory is expensive for small forest owners because of the disproportionately large sample size needed in small forests (i.e. number of plots or trees measured per hectare) to ensure samples accurately represent the whole woodlot area.

Remote sensing approaches that are currently being developed for forest inventory offer very real benefits to large forest owners, but are not well suited to small forests. Also, few small forest owners have the technology or skills to interpret remotely captured data, so consultants have to be employed, adding further to costs.

With small forest owners specifically in mind, researchers aim to:

  • investigate approaches that make forest measurement more cost effective and/or better
  • make the benefits of remotely sensed data and new statistical methods available.

UAVs for woodlot inventory

The potential to use UAVs for inventory is being investigated: the rapid development of UAVs, including associated miniaturised scanners, is exciting. Sampling of a case-study 40-hectare woodlot in the central North Island using a UAV is complete, and methods for generating three-dimensional information on the forest canopy using the imagery captured have been developed.  Further analysis, leading to recommendations on sampling design, statistical techniques, and practical data collection methods, is underway.

A community approach

Another option being considered by researchers is the potential to amalgamate and share data from a community of woodlot owners.


For this approach to be successful, researchers need to engage with a community of small forest owners who would be willing to contribute to a database of field plot data, ideally using data that they have, or would be, going to collect anyway. This information can then be combined with other freely available remotely sensed data collected by regional or national authorities to generate forest assessments for individual woodlots.