Report on the ACACA (AFFA) funded 2001 Eucalypt Mission to China

by

Brad M. Potts¹, Greg Dutkowski¹, Philip Smethurst² and René Vaillancourt¹

CRC for Sustainable Production Forestry,
¹School of Plant Science, University of Tasmania,
²CSIRO Forestry and Forest Products

• 1. Executive summary
• 2. Objectives
• 3. Terms of reference
• 4. Short-term strategies for the eucalypt expansion in Fujian
• 5. References
• 6. Opportunities identified
• 7. Talk Abstracts
• 8. Key Places Visited

1. Executive summary

A 10-day mission to China was undertaken by four scientists from the Cooperative Research Centre for Sustainable Production Forestry (CRCSPF) as part of the Australia-China Agricultural Cooperation Agreement (ACACA). The mission was instigated following a proposal by the Fujian Forest Research Institute. The higher altitude forestry region in the northwest of Fujian province was visited to assess the options for eucalypt introduction after a severe frost in 1999 curtailed plantation development. Fujian forestry organizations see the expansion of eucalypts into these colder regions as high priority, with a 60,000-hectare estate planned to provide fibre for local industry. The initial plantings in Fujian were mainly based on E. grandis and its hybrids, selected in more tropical southern China. With a need to develop germplasm that will tolerate cold winters, yet a sub-tropical, high-rainfall summer, the Fujian Forest Research Institute was interested to introduce summer rainfall provenances of E. nitens and the development of E. grandis x nitens hybrids. For hybrid development they were also interested in the development of potted seed orchard technology and learning advanced pollination techniques.

The exchange of technical information was undertaken by CRCSPF scientists presenting seminars at the Forest Genetic Research Department of Nanjing Forestry University, the Institute of Soil Science of the Chinese Academy of Sciences, the Fujian Forest Research Institute in Fuzhou, and the Fujian Agricultural and Forestry University in Nanping. The eucalypt mission assessed various options for introducing cold tolerant eucalypt germplasm into this region. However, rather than generating hybrids it was recommended that resources would be better focused at this stage on:

1. more extensive species selection and provenance/family testing of key species;
2. better testing and selection of frost resistant material already identified in provenance/family trials for seed and clonal deployment;
3. testing of clones already developed by other organizations that are breeding for similar climates;
4. implementation of wood property assessments;
5. increasing knowledge of flowering and its manipulation (e.g. paclobutrazol) in this environment.

Multi-site testing with smaller trials is favoured over large single site trials. Planting trials across altitudinal or latitudinal gradients will be a way of ensuring the germplasm being tested is subject to discriminating natural frosts on at least one site.

Key opportunities identified include:

1. collaboration between Fujian Forest Research Institute and the Australian Tree Seed Centre of CSIRO Forestry and Forest Products and Queensland Forest Research Institute on eucalypt introductions;
2. interaction between the Forest Genetic Research Department of Nanjing Forestry University and the CRCSPF/ University of Tasmania/CSIRO in the areas of quantitative and molecular genetics;
3. collaboration between the Nanjing Institute of Soil Science and the CRCSPF/ CSIRO in the area of soil fertility diagnosis.

2. Objectives

Four scientists from the Cooperative Research Centre for Sustainable Production Forestry (CRCSPF) were to visit China on a 10-day mission. The mission was proposed by the Fujian Forest Research Institute to look at options for developing cold tolerant eucalypts for the higher altitude regions in Fujian province. Eucalypts had been shown to grow much faster than previous plantation species and to have good wood quality. They were particularly interested in introducing summer rainfall provenances of E. nitens and developing E. grandis x nitens hybrids. For hybrid development, they were also interested in the development of potted seed orchard technology and learning advanced pollination techniques. The mission therefore focused on exchanging technical information on breeding and plantation management, assessing the options for introducing cold tolerant eucalypt germplasm into Fujian province, and identifying opportunities for interaction between the Chinese and Australian forestry organizations.

This visit is to be followed by a visit to Australia by a Chinese delegation in 2002.

3. Terms of reference

The mission was funded by the Australia-China Agricultural Cooperation Agreement that provides funding for agriculturally oriented exchange projects between Australia and China. Agriculture, Fisheries and Forestry Australia (AFFA) and the Chinese Ministry of Agriculture (MoA) jointly fund and administer the Agreement. It was the later organization that put up the project from the Fujian Forest Research Institute. The CRCSPF scientists on the mission included Brad Potts, Greg Dutkowski, Philip Smethurst and Rene Vaillancourt. In China, the mission was hosted by Prof. Yang Zongwu, assisted by Ms Li Zhe Zheng and Mr. Tang Fanglin, of the Fujian Forest Research Institute. The Australian delegation also requested they visit Nanjing Forestry University, Nanjing Institute of Soil Science and the Fujian Agricultural and Forestry University.

The province of Fujian has a sister state relationship with Tasmania and has been previously visited by Tasmanian forestry and political representatives. Forestry in the province is mainly confined to hill and mountain slopes as all flat land is used for higher value agriculture and the lower slopes for fruit trees. The inland regions of the province are exceptionally rugged and this is the main forestry area for the province. Current dominant forestry species are mainly Chinese fir (Cunninghamia lanceolata), Masons Pine (Pinus massoniana) and bamboo. However, trial plantations of eucalypts, which commenced in coastal regions nearly a decade ago with the introduction of E. grandis x urophylla clone(s) from Brazil, have showed the superior growth potential of eucalypts compared to local species, even in the higher altitude forestry zone (e.g. 1997 plantations achieved up to 14.5 m height in 3 years). The rapid early growth of these clones revived interest in establishing eucalypts in the northwest region of Fujian province as a fibre source for two local pulp mills and a factoring producing medium density fibre (MDF) board in the Min Bei district of Fujian province, one of which, Fujian Qingzhou Paper Mill, is the second largest in Fujian. It is planned to rapidly establish a 60,000-hectare estate in this district, half of which will be eucalypt plantations harvested on a short rotation in areas under 400m altitude. In 1998, technology was also developed to use young (5-6 years) eucalypts for fibreboard. The total eucalypt plantation estate in all of Fujian province was 7,000 hectares in 1998, 15,000 hectares in 2001, and set to expand further.

The interest in eucalypts in Fujian is coincident with a general expansion of eucalypt plantations into colder regions of China. There is already an ACIAR project involving CSIRO, Forestry Tasmania, and CFTT aimed at developing germplasm and production systems for cold tolerant eucalypts for use in cool regions of southern China and Australia. Furthermore, in Hunan province pilot plantings of eucalypts based on cold resistant clones of E. camaldulensis have recently been established. New eucalypt plantings in the higher altitude regions of Fujian (Min Bei) commenced in 1997 and were mainly based on E. grandis, E. urophylla and E. urophylla x grandis hybrids (urograndis) selected by organizations in southern, tropical China for high growth (e.g. China Eucalypt Research Centre at Zhanjiang which is a branch of the Chinese Academy of Forestry). These taxa are the main source of clones used for the extensive eucalypt plantations in tropical regions in southern China. However, the expansion of eucalypt plantings in the Min Bei region of Fujian province was curtailed in November, 1999 by an extreme frost that killed or severely damaged foliage and stems over a large proportion of the fledgling estate (3,000 hectares). In the vicinity of Yongan, over the altitude range of 200-500m, where many plantations were damaged, a high-pressure system resulted in night-time temperatures of between -5 and -8°C for nearly one week (-11 °C in the high mountains), coupled with normal daytime temperatures and sunny weather. This frost event was considered a once in 50-year event for this specific area and even caused severe damage to banana plantations in lower altitude regions near Pinghe. The E. urophylla and urograndis plantations were killed by the frost, but although E. grandis was damaged the vast majority of trees recovered by coppice. E. dunnii plantings were reported as undamaged. Most frost damaged stems were rapidly harvested and utilised for mushroom compost or poles for fish farms. In all cases the recovery with this treatment was good but plantations that were not felled showed persistent die-back and growth check. The frost initiated a re-assessment of the germplasm being planted and identified the need for more frost resistant germplasm as most of the estate planned for Min Bei is in areas that are colder than currently planted. Fujian forestry organizations and the Chinese government see the expansion of eucalypts into these colder regions as high priority.

Finding the optimal eucalypt germplasm for northwest Fujian is challenging, as the climate of the area is still sub-tropical in many respects with high summer temperatures and rainfall, yet subject to cold snaps during the dry winter months. In Min Bei, most rainfall occurs in summer months from March to June whereas the dry season extends from July to February. The annual average rainfall is between 1400 and 1700mm, and the average annual temperatures range from 17.6 to 18.9 °C. The highest temperatures occur at the end of July to the beginning of August where temperatures may reach 36-40°C. Frosts begin at the end of November and may occur up to March, with approximately 80 days with frost occuring per year and in some winters, snow will occur. The minimum nighttime temperatures average is -2 to -5 °C.

Many species of eucalypt had been first introduced into the province as ornamentals in the 1960's, and Corymbia citriodora plantings are widely scattered through lower altitude regions particularly in the south. From 30-40 species are said to have been introduced over this period. Species trials have also been established at various stages (e.g. 1994) with species such as E. grandis, E. saligna, E. camaldulensis (from Yunnan), E. dunnii, E. nitens, E. propinqua, E. urophylla, E. globulus ssp. maidenii (from Yunnan) and E. grandis x urophylla hybrids. The E. nitens tested is said to be from a Tasmanian source (probably of seed orchard origin as this species is not native to Tasmania). In coastal regions, it appears that E. urophylla grows best, but it is not frost resistant. E. globulus has been tested in Fugian but does not grow well. E. dunnii was reported as having better frost resistance than E. camaldulensis, E. saligna and E. grandis and survived the 1999 frost undamaged when E. grandis, E. urophylla and hybrids were damaged.

There is already a good base for selection of frost resistant germplasm of E. grandis as one of the large family trials that was established in 1996 with seedlots from the Australian Tree Seed Centre, CSIRO (via CERC) was frost damaged in 1999 (age 3.5 years). This trial was near Yongan and includes 205 families from 12 native provenances and was assessed for form, growth and frost resistance at age 4 years. Sixty four cold-resistant selections (the best individual from each family) have just been grafted into a seed orchard (30 ramets were grafted onto seedlings growing on site). A partner trial with 193 of the seed lots from 18 provenances is planted at a lower altitude in the vicinity of Pinghe. Following the frost 169 phenotypic selections (mainly E. grandis) were made for frost resistance in plantations around Yongan that were derived from seed orchard seed from Sichuan province. Mother plants were established from these selections and cuttings from these mother plants used to establish 5 trials (1 site with 25 clones, 4 sites with 100 clones). Informal discussion suggested that Fujian, Yongan Forestry Group Joint Stock Company also had a joint project with one of the Universities in Shanghai aimed at genetically engineering increased frost resistance in eucalypts.

4. Short-term strategies for the eucalypt expansion in Fujian

The eucalypt mission assessed the various options for the introduction of cold tolerant eucalypt germplasm into this region and the most rapid approaches to get improved germplasm into plantations. However, rather than hybrid production and development it was recommended that resources would be better focused at least at this stage on the options detailed below.

4.1 Define breeding objectives and identify key selection traits

Identify potential markets (e.g. pulp and fibre board) and determine breeding objectives. Current experience would suggest that growth rate, frost resistance/survival, form, wood density and pulp yield are likely to be key breeding objective traits.

4.2 More extensive species/provenance/family testing

• Undertake climatic matching of key planting zones in Fujian with climates in Australia to identify species and provenances growing in these climates for testing in Fujian. Such work could be undertaken with the Australian Tree Seed Centre.
• Extend testing of E. dunnii to further sites in the Fujian province. This species has performed extremely well in the summer rainfall regions in South Africa (Swain and Gardner 2000) and in trials in Northern NSW and Queensland in Australia (Lee et al. 2000) and was undamaged in the 1999 frost in China. However, the poor flowering of this species may limit its introduction.
• Rapidly test provenances/families of E. maidenii (e.g. Yambulla, NSW; Lee et al. 2000) and northern provenances of E. nitens.

4.3 Exploitation of the established E. grandis base

There is already, an excellent base for selection of frost resistant germplasm of E. grandis with several large family trials in Fujian. One of the largest trials was established near Yongan with seed lots from the Australian Tree Seed Centre. This trial has been assessed approximately 6 months after the 1999 frost for frost damage, form and growth. The best individual in each of the best 64 families has been recently grafted into a seed orchard near Yongan. A partner trial near Pinghe was undamaged which will allow information on wood properties and further information on form and growth to be collected for the same seed lots. Options include:

• Implementation of wood property assessments using low altitude sites (e.g. near Pinghe) for wood property traits (e.g. pilodyn penetration or basic density of cores).
• Import native stand seed for direct establishment of plantations in the milder regions in Min Bei from the native provenances with the best frost resistance and growth. As information on wood density becomes available, the provenance(s) selection should be based on the best combination of frost resistance, growth, form and wood density.
• Clone the original 64 ortets selected by causing coppice/epicormic shoot production through minor damage to base, followed by tissue culture to establish mother plants for hardwood cuttings, and establish clonal tests.
• Re-locate seed of the 64 selected families (from CERC, ATSC or Fujian Forest Department) and establish:
  • new trials along a frost gradient which can be thinned for conversion into seedling seed orchards;
  • clone 10 seedling from the top 30 families on a combination of frost resistance, growth and wood density, and establish clonal tests along an altitudinal gradient (300 clones x 5 reps per site).
• Obtain new seed collections from the most frost resistant provenances.
• Clonal seed orchard:
  • monitor graft success and incompatibility;
  • monitor flowering abundance and season of flowering of each clone;
  • re-graft and relocate top selections at other sites (e.g. near Fuzhou) to allow optimal sites for flowering to be identified;
  • apply paclobutrazol at age 2-3 (optimal time and dose will need to be pre-determined).
• Climatic matching of the forest regions in Fujian with other parts of the world to identify species and sources of advanced material for introduction.

4.4 Importation of germplasm selected in similar environments

• Key climatic zones to examine are Australia (northern NSW and Queensland), Brazil, South Africa and Florida.
• There is an advanced program breeding E. grandis for frost resistance in Florida.
• South African organizations involved in breeding and selecting species such as E. dunnii.
• Several tropical species are being bred in northern Australia by the Queensland Forest Research Institute

4.5 Trial sites and designs

Multi-site testing with smaller trials is to be favoured over large single site trials. Planting trials across altitudinal or latitudinal gradients will be a way of ensuring the germplasm being tested is subject to discriminating natural frosts on at least one site (see Cauvin and Potts 1991).

4.6 Increase knowledge of flowering and its manipulation (e.g. paclobutrazol) in the Fujian environment

For example, it will be important to identify the best conditions for flower and document the flowering times of the key species of interest, as well as the provenances and clones of E. grandis.

An example of the type of experiment required to identify the optimal time of year for the application of paclobutrazol is detailed in Jones et al. (2000; Figure 1). The optimal dose will also need to be determined by experimentation.

4.7 E. grandis x nitens hybrids

E. grandis x nitens hybrids are being tested in New Zealand (Shelbourne et al. 1999), South Africa (Verryn 2000) and Australia (APP). High levels of inviability in F₁ hybrids of this cross have been reported (Shelbourne et al. 1999), which is common when producing interspecific F₁ hybrids. In the case of New Zealand, selected hybrids have now in the process of being cloned and tested in field trials. However, Shelbourne (2000) notes: '...7 years from initial controlled pollination, we have, as yet, been unable to produce enough stock of normal hybrid individuals to properly evaluate this hybrid. ... Where there are many (eucalypt) species to choose from, its is arguably more cost-effective and ecologically safer to introduce and test different species that promise acceptable pulping properties and choose well-adapted fast-grown provenances, than to develop this hybrid.' They are simultaneously working with E. fastifata as well as E. globulus ssp. maidenii that is considered promising.

Pursuit of this hybrid option should not detract from the key options mentioned previously as it is expensive and slow to develop hybrids. Depending upon whether the hybrids are tested before cloning, development of such hybrids could take from 8 to 15 years before tested selections are transferred into plantations.

The quickest way to obtain such hybrids is to import selected hybrid clones from elsewhere for testing in Min Bei or use pre-established arboreta in China or overseas (e.g. in Australia E. nitens - Forestry Tasmania or APP; E. grandis — CSIRO) to undertake the crossing.

4.8 Other hybrid combinations involving E. grandis

Other hybrid combinations of E. grandis that have been reported are listed below, some of which are under development and may be worth testing.

MANIPULATED HYBRIDS

Species	Reference
E. urophylla	Vigneron and Bouvet 2000 de Assis 2000 Wu et al. 1996 D. Boomsma pers. corn.
E. botryoides	D. Boomsma pers. corn.
E. pellita	Griffm et al. 1988 de Assis 2000
E. alba	Griffm et al. 1988
E. tereticornis	Griffm et al. 1988 Vigneron and Bouvet 2000 Verryn 2000
E. camaldulensis	Griffm et al. 1988 de Assis 2000 Verryn 2000 Sasse et al. 2000 Dale et al. 2000
E. dunnii	Griffin et al. 2000 de Assis 2000
E. nitens	Shelbourne et al. 1999 Verryn 2000 Tibbits 2000
E. maidenii	D. Boomsma pers. com de Assis 2000
E. globulus	Griffm et al. 2000
E. gunnii	Potts unpubl. data
E. pulverulenta	Paton 1981

4.9 Silvicultural Research and Management

Various aspects of site and stand management were observed and discussed during the mission, but, as this was not the main focus of the mission, no experiments were visited or formal discussions held on this topic. In general, these issues of early stand management seemed to be reasonably well understood and managed, and research has already been initiated to address the main topics of site selection, slash management, cultivation, weed control, and fertilization. Fine tuning of many of these issues will need to be addressed by future research, and there are experts at the Fujian Forest Research Institute, e.g. Mr Li Baofu in fertilizer research, and in the forest districts and companies, who can guide this work. Soil fertility management would benefit from the use of calibrated systems of soil fertility diagnosis.

Currently, silvicultural research is being carried out in the less-frost-prone areas, but the patterns of response will need to be checked also in the frost-prone areas once a frost-tolerant genotype has been identified since different genotypes or species will be used. At that stage also, application of empirical, mechanistic and hybrid growth models would be useful in linking site attributes, management effects, and the physiological requirements of the genotypes to predict leaf area development and stem growth.

It was noticeable that many of the plantations we visited suffered from severe competition from weeds, despite having received one or two manual weed control treatments. More frequent weed control, or the use of longer lasting chemical methods deserves more attention. Interest is developing also in such topics as thinning, pruning and later-age fertilization, but short rotations due to high demand for pulpwood have resulted in these topics being of low priority.

5. References

Cauvin, B. and Potts, B.M. (1991). Selection for extreme frost resistance in Eucalyptus. In 'Intensive Forestry: The Role of Eucalypts. Proceedings of the IUFRO symposium, P2.02-01 Productivity of Eucalypts, 2-6 September 1991'. (Eds A.P.G. Schönau.) pp. 209-220. Durban, South Africa. (Southern African Institute of Forestry.)

Jones, W.R., Clarke, C.R.E. and van Staden, J. (2000). Understanding the breeding system of cold tolerant Eucalyptus species and its impact on seed production. In 'Forest Genetics for the Next Millennium, Proc. of IUFRO Symposium, Durban, South Africa 8 to 13th October 2000'. pp. 146¬150. (Institute for Commercial Forestry Research: South Africa.)

Lee, D.J., Nikles, D.G. and Dickson, R.G. (2000). Prospects of eucalypt species, including interspecific hybrids from South Africa, for hardwood plantations in marginal subtropical environments in Queensland, Australia. In 'Forest Genetics for the Next Millennium, Proc. of IUFRO Symposium, Durban, South Africa 8 to 13th October 2000'. pp. 164-168. (Institute for Commercial Forestry Research: South Africa.)

Shelbourne, C.J.A., Hong, S.O. and McConnochie, R. (1999). Early results from trials of interspecific hybrids of Eucalyptus grandis with E. nitens in New Zealand. New Zealand Journal of Forestry Science 29, 251-262.

Shelbourne, C.J.A. (2000). Some insights on hybrids in forest tree improvement. In 'Hybrid Breeding and Genetics of Forest Trees. Proceedings of QFRI/CRC-SPF Symposium, 9-14th April 2000 Noosa, Queensland, Australia'. (Ed. H.S. Dungey, M.J. Dieters and D.G. Nikles.) pp. 53-62. (Department of Primary Industries: Brisbane.)

Swain, T.L. and Gardner, R.A.W. (2000). Eucalyptus dunnii provenance/progeny trials in KwaZulu-Natal, South Africa - Final measurements and pulping properties. In 'Forest Genetics for the Next Millennium, Proc. of IUFRO Symposium, Durban, South Africa 8 to 13th October 2000'. pp. 221-227. (Institute for Commercial Forestry Research: South Africa.)

Verryn, S.D. (2000). Eucalypt hybrid breeding in South Africa. In 'Hybrid Breeding and Genetics of Forest Trees. Proceedings of QFRI/CRC-SPF Symposium, 9-14th April 2000 Noosa, Queensland, Australia'. (Ed. H.S. Dungey, M.J. Dieters and D.G. Nikles.) pp. 191-199. (Department of Primary Industries: Brisbane.)

6. Opportunities identified

Collaboration between the Forest Genetic Research Department of Nanjing Forestry University and the CRCSPF/University of Tasmania/CSIRO in the areas of quantitative and molecular genetics.

We found this group to be enthusiastic, with a high level of expertise. This research group had the closest interest of any group that we visited to our areas of expertise. NFU is the number one forestry university in China, specialising in forest genetics. Many of it's post-docs and staff have received training and spent time in the USA. Part of the reason to send people overseas is to increase their English fluency. We believe that as this group increases its work on eucalypt molecular genetics they might consider sending people to work in Australia rather than the USA. Both parties were keen to explore possibilities of collaboration and exchange. Information was passed to Prof. Wang, who was responsible for International Programs of the NFU. They do not currently have links with any Australian University and expressed a wish to develop such links. One possibility is for the CRCSPF to run a week long course on 'Quantitative Methods for Tree Breeding' at Nanjing. This course has already been run successfully in Australia and is to be presented soon in Chile. If we can establish a reputation for training in quantitative genetics for forestry there may be good flow-ons to international post-graduate students in this field. We also see possibilities for visiting scientists and post-graduate training on molecular genetics of eucalypts in Dr. Vaillancourt's laboratory at the University of Tasmania as well as with other forestry molecular groups in Australia (e.g. CSIRO, Southern Cross University).

Collaboration between the Institute of Soil Science of the Chinese Academy of Sciences, Nanjing and the CRCSPF/CSIRO in the area of soil fertility diagnosis.

This institute has a high level of expertise in soil science and apparently already has links with Australia in the field of solute transport and fertility management. Their main Australian contact is Prof. Robert White, University of Melbourne. The presentation by Dr Smethurst attracted keen interest in developing and testing nutrient concentrations in soil solution as indicators of soil fertility. The audience seemed to grasp the sound theoretical basis of the methodology and the potential to apply the methodology rather cheaply using 'Rhizon Samplers' to sample the soil solution from a paste extract, and the 'Nova' spectrophotometer to analyse concentrations of inorganic forms of macronutrients. This methodology has been tested successfully in plantation forestry, but not yet in agriculture or horticulture. The Nanjing Institute of Soil Science has links with several field experiment stations that probably offer the opportunity to test this methodology in a variety of agricultural and horticultural cropping systems. Testing of this methodology in plantation forestry in China could also be pursued if colleagues at Nanjing thought that would be useful. Fertility management in plantation forestry, as discussed and inspected during the visit, seemed to be well advanced, but would benefit from optimisation that involves appropriate soil fertility diagnosis. Interactions with plantation forestry in China in the field of fertility diagnosis could be pursued through Fujian Forest Research Institute and other similar organizations in the country. It may by possible to propose such interactions under the 'Domestication of Australian Trees' project. The possibility of interactions between Australia and China in this area should constitute a sound project for funding by ACIAR. Dr Smethurst intends to discuss these ideas with CSIRO, Prof. White and ACIAR.

The key area identified to provide a solid foundation for the expansion of eucalypt plantations in the NW region of Fugian involves species and provenance introductions as well as testing of selected families and clones from pre-established trials.

The best arrangement to achieve this objective is for Prof Yang and the Fujian Forest Research Institute to interact directly with the Australian Tree Seed Centre of the CSIRO Forestry and Forest Products. The Australian Tree Seed Centre specialises in the introduction of species and provenances into sub-tropical and tropical regions, and already has a major project on eucalypt introduction into China. The Fujian Forestry Department is a collaborator on this project, but mainly in the area of silviculture. In collaboration with ACIAR, they have a program 'Domestication of Australian Trees' (DAT) which would be an ideal means of introducing new species and provenances (e.g. into the more frost prone areas of Fujian). This project also supports basic training in breeding and experimental design and analysis.

7. Talk Abstracts

7.1 Eucalypt plantation management: nutritional and non-nutritional factors

Dr. Philip Smethurst

Abstract:

Eucalypt plantations have the potential to achieve high growth rates and yield a range of valuable wood products. However, there are many opportunities for mistakes during the plantation management cycle that can have detrimental effects on the quantity and quality of wood produced, the quality of the soil, and quantity and quality of water in groundwater and streams. Goals, comparisons of methods, and remaining research questions will be discussed in relation to various management options: cultivation, seedling quality, weed control, fertilization, pest control, pruning, thinning, harvesting and slash management. Recently developed methods for assessing and managing nutrient availability will be presented that are substantially increasing productivity in Australian eucalypt plantations.

7.2 Managing Genetics to Maximise Gain

Mr. Greg Dutkowski

Abstract:

The key message of this talk is that for optimising genetic gains from forest tree breeding it is important to:

1. Know what you are aiming for
2. Know the genetic control of traits of interest
3. Know the biology of the species
4. Have a strategy to integrate all the elements and deliver as quickly as possible

7.3 Advances in eucalypt seed production systems

Dr. Brad Potts

Eucalypt plantations in Australia are currently derived from seed as opposed to clonal propagation systems. This is due to the difficulty and hence higher costs of cloning the main plantation species, E. globulus and E. nitens. On overview of seed production systems used for these species is given. These systems produce seed of varying levels of genetic gain and include:

• direct collection of seed from the best native stands
• conversion of plantations to seed production areas
• seed collection from phenotypically elite trees in plantations
• conversion of family trials to open-pollinated seed orchards
• grafted clonal seed orchards

Eucalypts can self pollinate to varying degrees and inbreeding depression is a major factor limiting genetic gains from open pollinated seed orchards. However, recent advances in techniques for controlled pollination of eucalypts have now opened the way for avoiding this problem through mass controlled pollination of elite families. Such systems are already operational for E. globulus in both Chile and Australia.

7.4 Application of molecular genetics in forestry: The case of E. globulus

Dr. Rene Vaillancourt

Abstract:

Molecular genetics is an integral part of eucalypt breeding research in Australia. There is great opportunity for advances in tree breeding and forest genetics by integrating this research with more classical quantitative genetic approaches. This talk will overview the benefits which molecular genetics research offers to tree breeding using Eucalyptus globulus as an example. Molecular genetics is being used to :

1. Improve quantitative genetic models used to predict breeding values
2. Determining relatedness and recovering pedigrees
3. Molecular breeding
   • marker-assisted selection
   • candidate gene selection
4. Monitoring genetic diversity and inbreeding
   • natural populations
   • breeding and deployment
5. Quality control
   • microsatellite fingerprinting
   • chloroplast DNA fingerprinting
6. Optimisation of propagation systems
   • outcrossing rate
   • contamination rates
   • paternity analysis
   • pollen dispersal

While molecular genetics has delivered great advances to our knowledge of tree genetics, it has already delivered direct and indirect benefits to E. globulus breeding programs in Australia.

8. Key Places Visited

Figure 1. Map of Fujian province in eastern China showing key places visited.

 

Photo 1 E. grandis and urograndis plantations which had been severely damaged by the November 1999 frost near Yongan (300-500m altitude) where night time temperatures dropped to -5 to -8°C for one week. In many cases frost damage resulted in death of whole stems or the upper crowns (left). If damaged stems were harvested immediately after the frost, they rapidly regenerated from coppice (right) otherwise stem deformation and death persisted (right). Near Yongan, most of the eucalypts (mainly E. grandis or its hybrids with E. urophylla) had the top 25-30% of the crown damaged in 1999. Younger plantations were more severely damaged than older ones by the frost and damage was worse in areas subject to cold air drainage.

Photo 2 Manual harvesting of a four-year old eucalypt plantation near Yongan. Forestry is usually confined to the steep hill slopes in the main forestry area of Fujian province. Eucalypts are harvested manually and therefore log sizes are required to be relatively small. The trees are cut with a chain saw, delimbed with a hook and carried to the road in 4m lengths. The logs shown will be used to make fibre board.

Photo 3 Trees undamaged by the 1999 frost were often left whereas damaged trees were felled and coppiced resulting in a multi-aged eucalypt plantation (near Yongan).

Photos 4 to 6 Mother plants used to produce hardwood cuttings. These mother plants were derived from phenotypic selection of trees (mainly E. grandis) in plantations which were undamaged by the 1999 frost and are the source of cuttings used to establish clonal tests (nursery of the Yongan Forest Company, near Yongan). The selections were felled and mother plants established from the coppice.

Photos 7 and 8 Hardwood eucalypt cuttings. The standard plastic bag nursery container is widely used in China and is filled with a soil mix containing little organic matter.

Photo 9 and 10 For planting, the soil is usually cultivated by hand 50x50cm and 40cm deep and fertilizer applied at and after planting. In some areas many of the seedlings are damaged by white ants necessitating the use of repellent around the base of the seedling. Planting is usually between Jan-April-May and white ants are active from March to June. Manual weed control is usually undertaken again at 6 months. Weed cutting for plantation establishment is totally manual and costs 225 RMB/hectare, fertilizers (urea) costs 250 RMB/hectare (per 200 kg of urea) and spreading 200 RMB/hectare. Labour costs are 30RMB/day ($1 = 4.22 RMB).

Photo 11 1997 planting of E. urograndis clones on Pinghe Forest Farm. The biggest tree at age 4 years was 22cm diameter (0.3m3). The plantation was planted at 1800 stems per hectare (to suppress weeds) and then thinned to 1200 stems at age 3. At  3 years of age the plantation yielded 15m3/ha of thinnings and if cut at age 4 would yield about 180 m3/hectare. The growth of nearby clonal trial (E. grandis, E. urophylla and hybrids) planted in March 1999 and measured in December 2000 was averaged 13.6 m for height and 9.6cm for diameter.

Photos 12 and 13 The first pilot plantation of Eucalyptus in the Fugian province planted in 1991 using tissue cultured clone of E. urograndis from Brazil on the Chantai Forest Farm. The tree height is approximately 20m. Parts of the planting were cut at 7 years of age and yielded 130m3/hectare. The planting was thinned in 1994 as dbh growth was slowing. Eucalypt wood is selling for 300 RMB/m³ delivered to the local depot, which often means transporting costs from hill tops to towns in the valley bottom on poor roads. In this lowland area near the large city of Xiamen, the timber is mainly used for boxes.

Photos 14 & 15 There are now 660 ha of eucalypt plantation on the Chantai Forest Farm. In the early years, the estate was established with tissue cultured plants, in 1995, 96 and 99 seedlings were used but they now use cuttings from tissue cultured plants. The main projected use of the timber is for pulp and fibreboard but as there is no pulp mill in this coastal area at the moment the timber is used to make boxes. The forest farm would like to increase the estate to 3,000 hectares but the available land for agriculture is limited due to the flat land being used for intensive agriculture and lower hill slopes used for growing fruit trees.