Project Update January-June 2021 - NZ Dryland Forests Innovation

NIR imaging for heartwood

Near-infrared imaging has been successfully used to assess heartwood quantity and quality in E. bosistoana and E. globoidea cores taken from NZDFI trial trees. The technique enables assessment of heartwood diameter as well as extractives content – the key indicator of durability - and how this varies across the stem.

The NIR technique has proved to be a quick and contactless method for assessing heartwood. It will facilitate phenotyping (i.e. describing the physical characteristics of heartwood) and can provide spatial information on heartwood quality. Clemens sees potential to develop the technology so it could be applied to test for durability, for example during the timber grading process.

Read the full Technical Report: Assessing heartwood in E. bosistoana cores from NIR hyperimages

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Modelling stem properties for eucalypts: Daniel Boczniewicz

Daniel Boczniewicz from Poland is focusing on modelling stem properties of durable eucalypts

I am happy to announce that compatible taper and volume equations for Eucalyptus globoidea have been completed. The models are used in an interactive tool I have built which, based on input data (DBH and tree height), is able to predict height of the heartwood, volume and taper of heartwood, wood inside bark and wood including bark. The tool also provides visualisation of all components. The fact that all components are compatible is what makes this study novel.

I have completed the field work for my second study objective and I am looking forward to processing and analysing the data collected. The next step is to explore environmental effects which influence the heartwood formation in Eucalyptus globoidea.

Some recent outputs

Daniel’s one-minute video explaining his research won this year’s University of Canterbury Visualise Your Thesis competition, and will now be entered into an international competition.
Daniel has also produced eight videos about Eucalyptus species, including two of log-peeling trials.
Finally, Daniel has co-authored an article “Global Tree Taper Modelling: A Review of Applications, Methods, Functions, and Their Parameters” published in Forests Journal.

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Drying collapse in durable Eucalyptus: Vikash Ghildiyal

Vikash Ghildiyal is from India, and is in the early stages of his PhD research into drying collapse during Eucalyptus.

Over the past six months, I have assessed the wood properties of E. quadrangulata (core samples taken from the breeding trial at Cuddons) and E. globoidea (samples taken from the breeding trial at Avery’s). Heartwood quantity (heartwood diameter) and quality (extractive content) were measured from the cores. Analysis of the data suggested heartwood quantity being under genetic control in both E. quadrangulata and E. globoidea, opening up the possibility of selecting superior plants. Heartwood quality (extractive content) was found to be variable and under genetic control for E. globoidea grown at the Avery trial, similar to what has been reported for E. bosistoana at age 7 and E. globoidea at the Atkinson trial.

Collapse was detected after drying in the E. quadrangulata samples but was less prominent than in the E. globoidea cores. As has been found in E. globoidea, collapse was under genetic control in E. quadrangulata. It is worth noting that collapse was absent in E. bosistoana cores previously assessed in the NZDFI breeding program.

Finally, in June 2021, I visited the Juken NZ Ltd Ngamu E. globoidea breeding trial with my PhD colleague Daniel Boczniewicz, where we cored around 900 trees. Assessments of heartwood properties are ongoing. Once these measurements are complete, NZDFI’s entire E. globoidea breeding population will have been phenotyped for heartwood, collapse, growth and form on three different sites. The final step will be calculating breeding values for the different families including Genetics x Environment effects, allowing the selection of superior planting material.

Boxplot of predicted extractive content in heartwood E. globoidea families grown at Averys, age 9.5 years.

Boxplot of heartwood collapse of E quadrangulata families grown at Cuddons, age 9 years.

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Posts and poles: Woodscape techno-economic analyses

Two techno-economic analyses using Scion’s ‘Woodscape’ model have been completed, evaluating in detail the potential to produce veneers and posts from durable eucalypts.

Techno-economic analysis of veneers and posts from specialty wood species (durable eucalypts)

This report assesses the potential for making durable eucalypt posts and veneers from E. globoidea in a combined process under three regime options (15, 20 and 25-year rotations). The conclusion is that this could be technically and financially viable at a scale suitable to supply the agricultural demand for naturally durable posts and to supply high stiffness veneer.

Return on capital employed (ROCE) in a processing operation is estimated at between 20% and 30%, depending on the price of veneer. A 20-year regime gives better results than the 15-year regime and similar results to the 25-year regime with the benefit of the material being available slightly sooner. The longer rotations (20 to 25 years) would give greater yields of veneers.

The area of forest required to service a plant making the posts and veneers was estimated at being between 1,500 and 2,000 hectares, depending on the regime used.

Techno-economic analysis of posts from specialty wood species and radiata pine

This study compares the potential for producing posts from durable eucalypt species compared with the well-established CCA treated wooden post market, as well as posts made from other materials. There are a wide range of non-wooden posts on the market, made from concrete, steel, recycled plastic and hybrids made from a mix of materials. Generally, these non-wooden posts have retail prices that are higher than the CCA treated wooden posts.

The report concludes that durable eucalypt posts would be cost-competitive with posts made from other materials, including CCA-treated radiata pine posts when the disposal cost of these posts is taken into account.

The potential demand for non-CCA-treated posts from organic farming and horticulture (including vineyards) is estimated at 17,000 cubic metres per annum. Much of this demand is anticipated to come from Marlborough: taking the durable eucalypt harvest volumes predicted from a 20-year rotation and the assumed conversion factors likely to be achieved it was estimated that a forest harvest area of 60 ha per annum would be required to meet the post demand from organic growers. This implies a total forest estate dedicated to growing durable eucalypt posts of around 900 ha.

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Contributor: Paul Schroeder, Proseed NZ Ltd

Work as part of the MPI One Billion Trees Partnership Project to propagate clonal XyloGene planting stock in a commercial quantity has continued at Proseed. Despite introduction of a new, improved set of clones for propagation in the second year of a three-year programme, Covid lockdown from March through May 2020 and budgetary constraints frustrating plans to set up facilities needed, around 15,000 rooted cuttings have been produced for planting. That is a 60-fold increase of original stock. Although production is less than targeted, improvement in capability has been significant.

This pioneering project has required considerable trial and fine tuning: from managing stool beds, to collection, preparation and setting of cuttings, maintenance of growing environments, choosing growing systems and developing growing schedules.

While most stools were grown on in planter bags, gulley and growbag hydroponic systems were also trialled. In future, a combination is likely to be used: growing stools through a series of planter bags and then boosting growth with fertigation. Using a custom nutrient solution with a higher ratio of trace elements, growth of stools in straight hydroponic systems was spectacular, but cutting material tended to be softer and less hardy.

Given low strike rates, maximizing propagation space productivity required cuttings to be set densely in small cells or plugs. The Jiffy and Ellepot systems being evaluated are completely biodegradable. Refinements such as improved temperature control, water pH correction, and shading have lifted average strike up to 74% which is a big improvement from earlier settings of around 30%. However, there is still large variation in strike rates between different clones, which does make inclusion of all desired germplasm into a clonal propagation programme difficult.

Treated with hormone and set under mist with bottom heat, cuttings begin rooting about one month after setting. Growing on requires them to be potted on from their inert setting media to a complete media in a larger container. ‘Forest Tubes’ were chosen since they are an established growing system that develops well-formed root systems, enables air pruning, and allows spacing in carry trays if required.

Commercial-scale propagation: a work in progress

Developing commercial scale propagation remain a work in progress. A better system than electrical heat pads for heating large propagation tables needs to be identified. Plug systems for rooting cuttings are working very well and will be suited to robotic handling in future.

While the forest tube growing system has proven satisfactory for this project it would not be so well suited to larger scale production. Handling of individual tubes during potting, growing on and dispatch is labour intensive. Critically, root systems must be well developed before plants are removed from tubes for dispatch, so as to maintain root ball integrity. Although initially expensive to set up, biodegradable container systems such as Ellepot and Grocoon are likely to be more suitable, particularly if robotic handling was to be employed.

Extra handling and variable root strike make production of eucalypts as rooted cuttings more expensive than from seed. Given highly variable strike rate between clones (as has been encountered with overseas clonal programmes), it is a highly constrained tool for distribution of superior germplasm. It could still be very useful for bulking up limited seed supply such as from the best of top families in NZDFI breeding programmes or from specific controlled crosses.

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In Vitro tissue culture research at the UC School of Biology

Contributor: Dr David Leung

Under NZDFI 1BT partnership project Proseed is working with Dr David Leung at University of Canterbury School of Biology to accelerate multiplication of E. bosistoana material using laboratory based tissue culture techniques.

With no previous research on E. bosistoana to refer to, David has had to use his experience with other species to develop techniques. Work began in July 2020 with the selection of three pedigreed individuals for micropropagation, with a further two lines selected in May 2021. The results are very encouraging, and the next critical phase is root formation.

: Bud break (click to enlarge)

: Continuous shoot proliferation in a microcutting free of any microbial contamination .

: Bulking up shoot number and further shoot proliferation from smaller pieces from a shoot cluster.

: Shoot elongation and isolation of single shoots

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Eucalypt health research update

Contributor: Dr Steve Pawson

Things are getting busier as far as eucalypt pests work goes here at the School of Forestry.

We have recently welcomed Carolin Weser to the team. Carolin started her PhD in May and her work compliments research by Leslie Mann who is quantifying the resistance and tolerance of Eucalytpus species and the clones and families of E. bosistoana to damage by Paropsine beetles in general.

Carolin is working to understand the biology/ecology of Eucalyptus varigated beetle (EVB) in New Zealand, which will inform management strategies into the future. As EVB is regulated as a new organism we are looking to convert part of our Forest Health lab into a containment facility to support additional laboratory experiments that will complement her field studies.

We are also collaborating with other teams at the University of Canterbury – for example, the Waterways Centre, and their new LiDAR + RGB imagery resources, which should enable Leslie to investigate how we might quantify defoliation by these beetles by remote sensing. If successful this will allow us to assess resistance and tolerance and the impacts of these Paropsine beetles at much larger scales than previously.

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Carolin Weser joins the UC Forest Health team

Carolin Weser is the latest PhD candidate to join the University of Canterbury’s NZDFI research team. Carolin has a BSc in International Forest Ecosystem Management from Germany, and an MSc in International Nature Conservation from Lincoln University. She has worked as an ecological research assistant with Scion, Plant & Food Research and Lincoln University BioProtection Research Centre, and also spent time at the Netherlands Institute of Ecology and the University of Manchester before returning to New Zealand in 2020.

Carolin started her PhD in May 2021 and is investigating Paropsisterna cloelia, the eucalyptus variegated beetle (EVB), a relatively new species in NZ, first detected in 2016. Information on the phenology and ecology of EVB in New Zealand is limited, but current knowledge suggests it has the potential to be more damaging for eucalypt forestry than Paropsis charybdis, the eucalyptus tortoise beetle. EVB seems to produce more generations per year in warmer regions of the country, has a longer active period during the year, and feeds more voraciously.

Increasing the understanding of EVB ecology is essential and key to its successful management. Consequently, the aim of the project is to study the phenology of EVB and investigate predators and parasitoids in the field.

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Leslie Mann: Paropsine damage impact on Eucalyptus species

Leslie Mann from Switzerland is researching eucalyptus defoliation by Paropsine beetles including Paropsis charybdis and Paropsisterna cloelia (Eucalypt Variegated Beetle, EVB).

Based on fieldwork, I have been able to correlate defoliation rate (CDI) to the growth rate (height and DBH gain). I previously found that the species the least defoliated were E. cladocalyx, E. globoidea, and E. macrorhyncha. The most defoliated species were E. bosistoana, E. quadrangulata, E. camaldulensis, and E. tricarpa. My new findings were that the most damaged species were the ones that had the smallest height and DBH gain.

Thus, we can assume that Paropsine browse could have a negative impact on Eucalyptus trees. Interestingly, the most damaged species also had the longest new shoots in October, and the species with a low defoliation rate had smaller new shoot length. This could be interpreted as a sign of tolerance - the species the most defoliated are growing more leaves to compensate for the foliar loss from the previous summer season.

Assessing tolerance in the field could be challenging because not all species are defoliated at the same level. That is why I decided to grow two species in a greenhouse: E. bosistoana (susceptible) and E. globoidea (resistant), meaning I had the same environment and the same defoliation level for both species. Stem diameter, height, and biomass were measured; I am still analysing my greenhouse data.

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Chamira Rajapaksha is from Sri Lanka, where she is a lecturer in the Department of Pharmaceuticals, University of Kelaniya. Chamira’s PhD work will contribute to assessing the potential for essential oils as a by-product of a durable hardwood industry.

"I have analysed the seasonal variation of essential oil content and composition in immature and mature E. bosistoana leaves for 24 months from March 2018 to April 2021. The highest oil yield and percentage of 1,8-cineole - the chemical compound having the characteristic eucalypt fragrance - were obtained from the leaves collected during the summer.

From the five families of trees in this experiment one family yielded significantly more oil than the other families, indicating scope for selecting planting stock with superior oil traits in a breeding programme. Identifying families with superior oil traits in the NZDFI breeding programme is my next objective.

Further, I have assessed the oil yields and composition of six more NZDFI eucalyptus species (E. argophloia, E. nitens, E. globoidea, E. tricarpa, E. quadrangulata and E. sideroxylon). The results revealed that E. bosistoana foliage has highest amounts of total oil (15.8 µL/g) and 1,8-cineole (62%) compared to the other species. The quantities of total oil and 1,8-cineole in E. bosistoana is comparable to that of E. globulus, the main global eucalyptus oil source.

An interesting observation was that, although E. argophloia and E. bosistoana are thought to be closely related, the essential oil of E. argophloia is not comparable to E. bosistoana. E. argophloia had lowest oil yield (1.4 µL/g) and 1,8-cineole was not presented."

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Seoljong Kim is from South Korea. Seoljong’s PhD is a genomic and taxonomic study of Eucalyptus species. One of his key research areas is to describe the differences between two closely related species, E. argophloia and E. bosistoana.

For the last several months, I have been analyzing genomic data of E. argophloia and E. bosistoana samples to understand the patterns of population genetic structure of the species. As a result, clear genetic differentiation between E. argophloia and E. bosistoana population groups was observed from both PCoA and STRUCTURE analyses (Figure 1, 2).

Among the three core population groups of E. bosistoana plants in NZDFI (SHR-Southern Highlands race, NSWR-South Coast New South Wales race, SWVC-Southwestern Victoria collection), SHR appears to be genetically different from NSWR (SHR is known to be a smaller form of E. bosistoana, see https://apps.lucidcentral.org/euclid/text/entities/eucalyptus_bosistoana.htm).

The morphology of collected fruiting material from a few of the plants from the SWVC families seems to be similar to that of E. melliodora, and suggests that these plants are not E. bosistoana. However, my genetic structure analysis shows that SWVC and NSWR are genetically similar (Figure 2). To clarify their taxonomic identification, flower and fruiting herbarium specimens are needed from all three family groups.

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2021 trials - establishment underway

This spring eleven new trial sites are being added to NZDFI’s network of 36 sites. These new trial sites will extend the geographic and climatic range of the network, and will include the first generation of Xylogene^TM improved genetic material, produced from elite families identified in the existing trial network.

New locations range from Northland to Canterbury. Some sites are being planted with multiple trials to fulfil multiple objectives, including (i) producing germplasm with improved phenotypic traits, (ii) providing a seed supply of superior genetic quality for forest plantings, and (iii) producing data for silvicultural management and growth modelling research and development work.

Paul Millen and Ruth McConnochie are planning and supervising trial establishment with the generous support of all the companies and landowners that are involved. The new trials are part-funded by our Te Uru Rakau One Billion Trees grant.

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Marlborough trials survive the floods

Two NZDFI trials were inundated by floodwater when the Wairau River breached stop-banks following the very heavy rainfall on 17-18 July 2021. During this period over 300 mm of rain fell in the headwaters of the Wairau with some homes, farms and vineyards in and around Blenheim and the Wairau Valley suffering serious damage.

The NZDFI trials at Northbank and Cravens Road surprisingly withstood rapid flows some 2-3 metres deep in places with little damage. A few trees were knocked over and debris ranging from river gravels to large logs and branches was left behind. Marker pegs have been damaged and covered in debris; clean up by local contractors has begun.

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Upcoming Marlborough workshop, 10^th November 2021

A full-day workshop/field trip is planned for Marlborough on November 10^th 2021 to introduce the concept of regional wood supply catchments of durable eucalypt forests and how one or more catchments could be established in Marlborough. The workshop follows the well-attended workshops in the Wairarapa and Hawke’s Bay. The target audience includes Marlborough’s viticulture, agriculture, horticulture and forestry sectors, especially those responsible for land-use planning.

The workshop will be based at the Marlborough Research Centre. Speakers will include Paul Millen, NZDFI’s Project Manager and Dr Clemens Altaner, who leads wood quality research for the NZDFI. Other local experts are being asked to attend including a representative from the viticulture industry to cover the potential demand from the sector for naturally durable timber posts. A visit to a near-by NZDFI trial will be included in the programme.

More details and registration information will be available soon.

NZDFI workshops are part-funded by the WIDE Trust.

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8. Final word from Paul

Earlier this year the Climate Change Commission consulted on proposals for action needed to reduce net carbon emissions to meet national and international targets.

NZDFI made a submission, supporting in principle the Commission’s proposals for New Zealand to move to a low emissions and circular bio-economy, partly to be achieved by a significant increase in new forest plantings and expansion of wood-based industries. We pointed out that the Commission had failed to recognise the potential for durable eucalypts (or indeed any alternative exotic species) as a contributor to New Zealand’s emissions reduction targets between now and 2050. So we proposed the Commission support NZDFI’s vision for 60,000 ha of plantations for durable hardwood production, or as permanent forests, in its final recommendations to Government.

Disappointingly – although perhaps not surprisingly given over 15,000 submissions were made - we have received no feedback, nor was there any change to the final CCC advice to Government.

More encouragingly, following our submission to MPI on proposed amendments to the ETS where we offered to assist with producing species-specific look-up tables for exotic hardwoods, we did have a meeting with MPI. What comes of this remains to be seen.

Although the wheels of change at policy level move slowly, the NZDFI continues to make great progress, and I would like to thank our partners, trial hosts and others involved for their continuing support. I believe our vision for durable eucalypt forests is an opportunity for significant investment in a new type of forestry in New Zealand that could deliver sustainable multiple benefits to regional economies and communities.

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