A WORKSHOP ON ISSUES AND STRATEGIES TO CONSERVE THE GENETIC RESOURCES OF PINUS RADIATA EX SITU¹

by

Colin Matheson, David Spencer and Ken Eldridge, CSIRO Forestry and Forest Products
PO Box E4008, Kingston, ACT 2604, Australia

At its 13th meeting in Rotorua, New Zealand in 1996, the Research Working Group No 1 of IUFRO set up a sub-committee to convene a workshop on the genetic conservation of Monterey pine. Accordingly the CONSERVE Workshop was held on 6 October 1998 in Canberra, Australia to bring together Australian and New Zealand plantation managers and researchers to develop a strategy for conserving the genetic resources of Pinus radiata outside California and Mexico. Proceedings have been published (Spencer et al., 1999) and are available from the authors of this paper.

BACKGROUND

Conservation of genetic resources of plants is an important component of long-term management for their sustained productivity and profitability, and this applies as much to Monterey pine (Pinus radiata D. Don) as to annual crops (Pistorius, 1997). Genetic diversity in forest trees is ideally conserved in situ in native populations. However natural populations are threatened by many factors, and valuable genetic resources are often at risk. Ex situ conservation methods, including plantations, conservation stands, seed banks or clonal archives, provide a prudent backup for breeders and ecological restorers should native populations be lost (Ledig et al, 1998).

Pinus radiata is one of the world's most important plantation forest tree species with about 4 million ha planted (Lavery and Mead, 1998), mostly in Australia, New Zealand and Chile, but with smaller areas in South Africa, Spain and elsewhere. Despite this very extensive planted resource, Monterey pine grows naturally in only five very small areas making up a total of only a few thousand hectares in California and Mexico. The Californian populations, Año Nuevo, Monterey and Cambria, are all on the coast between the cities of San Francisco and Los Angeles. The Mexican populations are located on two small islands off the Pacific coast, Guadalupe and Cedros. Experimental evidence suggests that these five small stands contain more genetic diversity than does the vast commercial plantation resource (Moran et al., 1988). It seems likely that the plantations have been derived mostly from only two of the native populations, Año Nuevo and Monterey (see also Burdon et al., 1998, Forest Genetic Resources No 26, pp 3-8).

As mentioned above, Pinus radiata represents a very high value to plantation forestry. In spite of this high value, the native stands are under threat from increasing urbanisation and disease. In both Monterey and Cambria, urban areas occupy an increasing part of the original Monterey pine forest and trees are cut down daily to make way for new development. On Guadalupe Island surviving trees are old and predation by goats removes any regeneration. A new disease to California, pine pitch canker, caused by the fungus Fusarium circinatum, has become established along the coast, having a devastating effect on all three mainland populations. At a recent conference it was stated that more than 90% of the trees in the Californian native stands will eventually succumb to the disease (Devey et al., 1999).

SEED COLLECTIONS

There have been 17 collections from the native stands other than the undocumented ones in the 19^th Century. Of the 17, only two have collected substantial amounts of seed, the 1978 Eldridge/Firth collection and the 1992 CAMCORE collection. The 1978 expedition, which was supported by FAO, collected over 70kg of seed, some of which was used to establish 49 field trials in Australia, 33 in New Zealand and more than 50 elsewhere in the world.² Many of these experiments are now approaching 20 years of age and before long will be harvested along with surrounding plantations. Substantial amounts of seed from the 1978 collection covering the Año Nuevo, Monterey and Cedros populations remain in the CSIRO seed store. Eight stands were established recently in collaborative projects between CSIRO, the Southern Tree Breeding Association (STBA) and the Western Australian Department of Conservation and Land Management (CALM), Australia. Two of the new stands involve Guadalupe and six involve the Cambria population.

Because of the pine pitch canker, it is unlikely that there will be further introductions from the native stands into major Monterey pine plantation countries in the near future.

THE WORKSHOP

The workshop, held on 6 October 1998 at CSIRO, Canberra, Australia, was attended by 25 participants representing plantation management and forestry research in Australia and New Zealand. The discussions were structured in two sessions addressing the following issues:

• identifying conservation needs and conservation criteria;
• developing a conservation strategy (where several models were considered together with cost estimates).

While recognizing the need for in situ conservation, it was decided to focus discussions on ex situ conservation in order to establish a coherent strategy to maintain conservation plantings in the longer term.

CONSERVATION CRITERIA

Participants were sub-divided into groups and asked to identify what they thought needed to be conserved and what conservation criteria should be used. The following was concluded from the discussions:

• Existing ex situ genetic resources need to be conserved since the threat of pine pitch canker precludes further introductions of material from the natural stands for the foreseeable future.
• To maintain alleles with frequency 0.01 or more in an open pollinated population, the effective population size should be at least 2000 for each population (Gregorius 1980).
• Efforts should be made to conserve the remaining natural stands and their genetic variation in situ. The question was raised as to whether the appropriate authorities in the USA would acknowledge conservation in situ as a responsibility.
• A risk management strategy should be developed incorporating the following:
  • in situ conservation
  • long term conservation without selection (ex situ)
  • utility conservation in the shorter term (ex situ).
• Conservation stands should be replicated across soil types and geographic boundaries to minimise risk of loss.
• Research needs to be conducted to determine or estimate:
  • what level of pollen contamination can be accepted
  • how many alleles have been lost from the populations already
  • to what extent have the wild genetic resources already adapted to local conditions.

DEVELOPMENT OF A CONSERVATION STRATEGY

One of the main issues in ex situ conservation is the question of regeneration. Various options exist, related to the objective. Six different options had been listed prior to the workshop and formed a basis for discussions on the development of a conservation strategy.

Conclusions of the discussion on conservation strategies

Participants discussed various conservation options and concluded:

• Controlled pollination is too expensive to be considered for use in any conservation strategy designed for Australia and New Zealand.
• All conservation plantings should have an effective population size of 2000 or more.
• For blocks of each population/sub-population of more than 20 ha, owners should be requested to extend the rotation length for as long as possible. In addition:
  1. new block plantings should be more than 20 ha and sub-populations, should be identified, especially if using the seed held in store by CSIRO;
  2. blocks of each population/sub-population of less than 20 ha should be replicated wherever possible; this is especially important for the Cambria population.
• Seed collections should be made from conservation blocks scheduled to be felled.
• The Guadalupe population is largely secured in ex situ collections.
  A conservation planting using seed from CSIRO and the CAMCORE collection was established at Burrungle (Australia) in 1996. In 1998 another planting was established some distance away at Tarpeena using vegetative propagules taken from this stand.
• For material originating from Cedros Island the following should be initiated:
  1. Seed held in store should be sown as soon as possible and containerised for planting in 1999.
  2. The issue of design and location should be reconsidered when germination results are known.
• There is a need to establish new stands to cover gaps, using CSIRO seed in store or seed collected from open pollination blocks in Australia and New Zealand.
• Ex situ resources of the Monterey and Año Nuevo populations are not currently under threat and are well-covered in existing conservation plantings.

FOLLOW UP TO THE WORKSHOP

In order to facilitate the implementation in Australia and New Zealand of priority action discussed during the workshop a committee of 6 persons was formed. The role of the committee would be to locate existing planted blocks of documented material from natural stands which are considered to have critical conservation value, to prioritise them and to initiate preliminary negotiations with the forest owners of such conservation blocks. In these discussions owners will be informed about the value of the stands and commitments of support will be sought. A next step would be to develop a Memorandum Of Understanding for use with owners and organisations controlling the conservation blocks ensuring future protection of conservation blocks and under which the issue of future access to the genetic material is agreed upon.

Another role of the committee would be to identify areas where additional plantings could be made representing a wide range of sites and thereby minimizing risk of loss due to unforeseen circumstances, and finally to prepare a detailed outline of an implementation plan that will fulfil the requirements of the agreed conservation strategy.

The possibility of involving also forest industries from Chile in the conservation strategy was discussed and it was agreed that the committee should contact potential Chilean collaborators, inform them of this initiative and invite them to participate in the implementation of the conservation strategy.

REFERENCES

Burdon, R.D., Firth, A., Low, C.B, Miller, M.A. (1998). Multi-site provenance trials of Pinus radiata in New Zealand. Forest Genetic Resources No 26, pp 3-8, FAO, Rome.

Devey M.E., Matheson, A.C. and Gordon, T.R. (1999). Current and Potential Impacts of Pitch Canker in Radiata Pine. Proc IMPACT Monterey Workshop, Monterey, CA, USA, 30 Nov to 3 Dec 1998. CSIRO Australia, 120pp.

Gregorius, H.R. (1980). The probability of losing an allele when diploid genotypes are sampled. Biometrics 36(4), 643-652.

Lavery, P.B. and Mead, D.J. (1998). Pinus radiata: a narrow endemic from North America takes on the world. In "Ecology and Biogeography of Pinus (Ed D.M. Richardson). Pp 432-449. Cambridge University Press.

Ledig T.F., Vargas-Hernández, J.J., Johnsen, K.H. (1998). The Conservation of Forest Genetic Resources. Journal of Forestry, Vol 96, No 1, pp 32-42. 1998.

Moran, G.F., Bell, J.C. and Eldridge, K.G. (1988). The genetic structure and the conservation of the five natural populations of Pinus radiata. Can. J. For. Res. 18, 506-514.

Pistorius, R. (1997). Scientists, plants and politics: a history of the plant genetic resources movement. International Plant Genetics Resources Institute, Rome, 134pp.

Spencer, D.J., Eldridge, K.G. and Matheson, A.C. (1999) CONSERVE: Strategies for Conserving the Genetic Resources of Pinus radiata outside California and Mexico. Proc CONSERVE Workshop, Canberra, ACT, Australia, 6 October 1998. CSIRO Australia, 23pp.

1. Original in English. Received October 1999
2. For further information on this seed collection please refer to Forest Genetic Resources No 7, p. 47 (1978), Forest Genetic Resources No 9, pp. 44-45 (1979) and Forest Genetic Resources No 26, pp 3-8 (1998)