Information note - A15

Workshop Report

Broadleaved Tree Improvement

A Forestry Research Co-ordination Committee (FRCC) Workshop on the subject ‘Improvement of Broadleaved Species’ was held on 26^th September 2000 at the Northmoor Trust, Little Wittenham, near Abingdon, Oxon. The workshop was co-funded by Forestry Commission, Ministry of Agriculture, Fisheries and Food, Department of Agriculture and Rural Development, Northern Ireland and Forest Service (Northern Ireland). The organising committee was C J A Samuel (Forest Research (FR)), Peter Freer-Smith, (FR), Peter Savill (Oxford Forestry Institute (OFI)), Karen Russell, (Horticulture Research International (HRI)) and Gabriel Hemery (Northmoor Trust).

Originally 90 people were invited to take part in the workshop. This included 17 members of FRCC and, as well as staff from FR, HRI, OFI and the Northmoor Trust, the organisers and main speakers being drawn from these sources. The remaining invitees included representatives of the British and Irish Hardwood Improvement Programme (BIHIP), the forestry teaching universities, FC, FE, RFS, TGA, TRADA, BRE, UKFPA, the Northern Ireland Forest Service, with Coillte and Teagasc from the Republic of Ireland. Those who attended are listed under the accounts of the four Group Discussions (see below).

The workshop took the form of 5 presentations followed by a period of discussion in which 4 subjects were considered in more depth. A visit to field trials was then followed by reports from discussion groups and a final summary.

Summary of presentations

Tim Rollinson, Head of FC Policy and Practice Division and Chair of FRCC.

In an initial welcome and review of the subject, attention was drawn to the function of FRCC Workshops in providing a forum for the discussion of policy priorities, technologies, time-scales and likely success of work in the field for the benefit of funders, researchers and beneficiaries. The factors which have affected interest in broadleaves (BL) were considered. These have included market changes, wartime demands, heavy concentration on conifers and the more costly aspects of BL management.

More recent interest has resulted from sensitivity to landscape and the need to promote greater access to forests through a wider range of uses. Increasingly, the public concept of BL woodland orientates itself around natural stands and conservation issues, failing to recognise timber production as one positive benefit of sustainable forest management. In examining the role of public funding for BL research, a balance between genetic improvement, and management had to be established, together with an assessment of the importance of quality. Ultimately appropriate research effort needs to be quantified and uptake of improved material by growers needs to be guaranteed.

C J A Samuel, Head of Tree Improvement Branch, FR.

A generalised scheme of tree improvement methods was initially presented to provide a basis for the details of the day’s discussion. Tree improvement research in BL in the FC has passed through phases of higher and lower input over the last 50 years. Inevitably breeders have been led to pursue methods which produce lower genetic gains over a short time span rather than being able to commit greater resources over longer periods to achieve higher gains. This led the FC to select plus-trees and to set up untested clonal seed orchards during the 1950-60s but only to evaluate range-wide variation in broadleaved species when a second phase of activity began in the 1990s. Future areas of work were envisaged as:

• Registration of more seed stands as a way of ensuring some immediate gain,

• Using the breeding seedling orchard (BSO) concept for initial breeding work in appropriate species,

• Developing methods of mass vegetative propagation for small quantities of elite material.

Future work will have to address current interest in appropriate and localised planting stock. It will become increasingly dependant on knowledge of the best sources of material for planting in the UK and the level of adaptation among native populations.

Ken Tobutt, HRI.

The work on forest tree improvement within HRI in recent years was presented. The work has been supported by MAFF funding aimed to increase the supply of suitable improved material for farm woodlands. HRI’s long experience with cultivated fruit species has been of great benefit and wild cherry was initially chosen as a native species with a fairly fast growth rate producing high quality timber. The closely related cultivated cherry is already well-understood genetically. The programme has combined traditional approaches involving the selection of plus trees and the use of clonal seed orchards with the breeding approach of controlled crossing and selection of seedlings from full-sib progenies. Initial production of improved material has used clonal techniques including the development of methods of micropropagation leading to the release in recent months of Wildstar clones. Selected clones are screened for bacterial canker resistance in the laboratory. In addition, the programme is also investigating the potential of interspecific hybrids and triploids. Molecular markers are also being sought using isoenzymes, RFLPs, AFLPs and microsatellites; this work is currently concentrating on markers for aspects of wood quality and pest resistance.

The approach evolved for cherry is now being developed for use in other species. So far HRI have been involved with work in all the species considered in BIHIP and participated in all their species groups. This has included the micropropagation of oak, controlled crossing in birch, a search for molecular markers in sweet chestnut and the selection of plus trees in walnut and ash.

Peter Savill, OFI and secretary of BIHIP.

The circumstances and initiatives which led to the development of BIHIP, a cooperative organisation incorporating researchers, producers and landowners, were outlined. BIHIP aims to promote the genetic improvement of broadleaved species through provenance testing, selection and breeding and depends largely on participating landowners and organisations to establish field trials in support of this. Education and publicity on the use of improved material are also promoted. Within BIHIP, activity is concentrated in 6 species groups dealing with ash, oak, cherry, walnut, birch and sweet chestnut. The groups have received funding directly from a range of sources, principally charitable organisations interested in hardwoods. It was suggested that across all species groups, funding of around £500k would provide effective support for the main objectives of the organisation over the next 10 years.

Gary Kerr, Silviculture and Seed Research Branch, FR

This contribution brought together the fields of genetic improvement and silviculture. Silvicultural systems advocated for broadleaves recognise the potential of a high quality final crop of 100-150 stems per hectare. At the moment, the high planting densities advocated provide the opportunity for intensive selection for the final crop as well as the silvicultural benefits of less branching and better site capture.

Limited attention, however, is paid to the genetic origin of planting stock, much of which may be of unsuitable origin of from unselected parent material. Not much is known about the gains in yield and quality which could result from more exact control of genetic origin, particularly as far as products of tree breeding programmes are concerned. Clearly breeding work carried out now has to anticipate a need for improved produce up to 100 years into the future and economic advantages to the grower. However, tree improvement was seen as such an integral part of any research aimed at improving lowland silviculture that support for it was seen as essential. Efforts to secure long-term funding for a limited number of the most important species were seen as the best way forward.

Summary of group discussion

Delegates has been allocated to Discussion Groups by the organisers, aiming primarily to provide specialists in the appropriate field in all groups and to distribute members of the same organisation across groups.

Group A – Approaches to breeding

Rapporteurs: David Thompson, Coillte and Malcolm Campbell, OFI

Present: Bart Banks (FC Advisory Panel)
Ned Cundall (FR)
Peter Freer-Smith (FR)
Gabriel Hemery (Northmoor Trust)
Peter Kanowski (ANU)
Niamh O’Dowd (Teagasc)
Anne Rae (Southampton University)
Sam Samuel (FR)
Peter Savill (OFI)
Ken Tobutt (HRI)

There was considerable discussion on the value of provenance work, given the range of issues such work can address. Provenance trials are an important first step in any tree-improvement programme and are also a sound basis for studying the impact of climate change on forest genetic resources. The phenomenon of increased yield through transfer northwards has now been identified for broadleaves using provenance trials. There is current interest and support for the use of field trials to study adaptive variation in native species in the UK. There was support for the view that the work carried out so far in the major species had given broad indications of suitable sources and that wider investigations, which would involve considerable expense, had no real further justification.

The promotion of greater use of material from registered seed stands was recognised as an important way of achieving immediate benefits and the provision in incentives, perhaps through the Woodland Grant Scheme, was advocated.

Field testing of selected material was felt to be essential by members of the group but it was recognised that unless a major increase in funding was directed towards broadleaved species, improvement programmes would largely have to proceed without this. The BSO approach, where its use is appropriate, goes some way towards this end.

Current provenance trials have identified significant provenance x site interactions for early vigour of both ash and oak. Such interactions need to be taken into account in the development of Breeding Seedling Orchards. It was strongly advocated that the development of successful methods through which small quantities of improved material could be multiplied by vegetative propagation to commercial proportions would be beneficial, not only for the small amounts of seed which are likely to emerge from Breeding Seedling Orchards (BSO) in the early stages but also for plus trees and elite selections from controlled crossing programmes.

The group briefly discussed:

• Marker Aided Selection – has good potential for clonal identification but development in more commercial species should be studied first.

• Wide hybridisation – debatable for native species but may have useful applications for walnut.

• Genetic modification – has high potential but is not an appropriate research area at present.

Group B – Demand, economics and market development

Rapporteurs: Roger Venables and Rick Worrell, Consultants

Present: Alex Argyropulo (Small Woods Association)
Peter Charlton (UKFPA)
John Fennessy (Coillte Teoranta)
Neil Hammatt (HRI)
Ralph Harmer (FR)
Stephen Head (Northmoor Trust)
Jim McAdam (DANI)
Tim Marks (HRI)
John Morgan (FE)
Bob Stone (MAFF)
Normal Weiss (BIHIP)
Jon Westlake (FC)

Discussion focused on two questions:

Does demand justify investment in tree improvement ?

The group recognised that there were alternative ways of increasing the economic value of broadleaved woodlands, of which tree breeding was only one; they potentially competed for research funds:

• Genetic improvement;

• Improved silviculture (e.g. high pruning);

• Better timber utilisation technologies.

Discussion revealed a strong ‘technology push’ for the genetic improvement of broadleaves from tree breeders and silviculturists, but not a strong ‘market pull’ from nurserymen and timber processors. Like breeders, a number of timber growers are highly supportive of research to achieve genetically improved broadleaves. Two main views emerged about the virtues of genetic improvement:

1. Improvement is not justifiable because:

• of market uncertainties – poor state of hardwood markets at present;

• novel technologies in the future which might not require straight. round logs;

• there is no apparent "public" demand for improved broadleaves (though there is for general broadleaf planting);

• there is little or no current demand for nursery stocks of improved material.

Proponents of this view favoured investing in utilisation technologies and possibly in improved silviculture.

2. Improvement is justifiable because:

• timber quality has always been valued irrespective of the actual utilisation technologies available;

• quality timber is easier to market as it has access to a wider range of markets;

• there is a demand for improved stock as demonstrated by uptake of "Wildstar" cherry;

• demand for improved stock will increase with better availability and with increasing understanding of the benefits;

• the "1/2p-worth of tar argument" which states that, considering the investment which goes into a broadleaf planting scheme, the additional (public and private) money required to use stock capable of quality timber production would be very small. It is not sensible to risk investment in planting trees by using inferior stock.

The group addressed the question of trying to equate demand with research costs and noted that Net Discounted Revenue-type calculations were rarely satisfactory as:

• not all benefits can be captured;

• discounting cannot deal satisfactorily with projects with up front investment costs but potentially infinite benefits streams (because long term future benefits are discounted to zero).

The point was also recognised that it is not just growth rate and form that are potential targets for improvement but also disease resistance. Time did not allow proper consideration of what traits should be improved and what the economic implications would be.

What measures are necessary to promote production of improved material ?

These were distilled to:

• Investment in research: this needed to be carefully targeted and relatively low cost (i.e. compared with the investment in Sitka spruce);

• Education of customers (and research funders !);

• Promotion of the products of improvement;

• Grants and regulations (e.g. requirements under WGS for applicants to show suppliers certificates demonstrating use of appropriate planting material) –this would only work if stocks were available;

• Getting supplies into nurseries !

It was noted that the price differential for improved stock:

• would need to be realistic so as not to put off purchasers;

• would probably not cover the full costs of research programmes.

Group C – Future funding and management of broadleaved improvement

Rapporteurs: Miles Barne, landowner and Christine Cahalan UW, Bangor

Present: Malcolm Beatty (DANI)
Bobin Bircham (BIHIP)
Richard Brand-Hardy (MAFF)
John Davis (BIHIP)
James Johnston (BIHIP)
Karen Russell (HRI)
Bob Selmes (FC)
Benjamin Slade
Mike Townsend (Woodland Trust)
Martin Wood (Northmoor Trust)

Currently public funding comes from:

• FC (almost all to FR) and MAFF (almost all to HRI) in Great Britain

• DARD and COFORD in Ireland

• Other funding comes from trust, charities and individuals. Much of this type is secured directly by BIHIP species groups

Other opportunities were seem to exist within:

• The EU - not only 5^th Framework funding but Eureka and Euroforest sources

• DETR – for more strategic work

The role of BIHIP was seen as increasingly important having established a good model for cooperation across a range of interests and for progress through the partnership with landowners in establishing, maintaining and ultimately benefiting from field trials. BIHIP was seen to be in need of a better-defined organisational structure and to present this to potential funders. Improvement of broadleaved species currently needed a firmer vision and strategy and BIHIP could play an important part in the process of developing these. [Re-organisation of the structure and constitution of BIHIP is currently taking place with this aim.]

The group agreed that future broadleaved tree improvement work should focus on a small number of species. Genetic improvement and the production of improved material is more difficult in species like oak with long generation interval and limited seed production. These factors make field testing very long term and seed orchards far less productive than they are for species like birch. It was suggested that work be restricted to the seven species covered by the existing BIHIP species group: ash (Fraxinus excelsior), birch (both the native Betula species?), oak (both Quercus petraea and Quercus robur?), sweet chestnut (Castanea sativa), sycamore (Acer pseudoplatanus), walnut (Juglans regia) and wild cherry (Prunus avium).

MAFF will be reviewing its tree improvement research next year. The review is likely to take place in July in London. Broadleaved tree improvement research has a relatively low priority within MAFF due to its limited alignment with the environmental objectives of the FWPS that have evolved in recent years. The need for further research will be one of the topics addressed at the review.

Group D – Integration of improved products with the development of woodland of the native type

Rapporteurs: Douglas Malcolm, formerly Edinburgh Univ. and Gary Kerr, FR

Present: Stan Abbott (FC)
David Blakesley (HRI)
Robin Buxton (Northmoor Trust)
David Henderson-Howat (FC)
Jason Hubert (FR)
John Kilner (DETR)
Paul Marsh
David Rees (Oxfordshire Woodland Project)
Tim Rollinson (FC)
Richard Smith (TGA)

The enthusiasm in Britain and Ireland for local and native material does raise difficulties for the development and supply of improved material. Purists are likely to identify the problems of planting genetically improved material close to native/local stands. However the group found the integration of improved material generally acceptable, provided it added value to the woodland concerned. Some concerns were expressed about the effects of narrowing the genetic base by the use of improved material and the inability to respond to climate change which this could produce. Overall, however, the group regarded the narrowing of the genetic base as relatively unimportant compared with increasing knowledge of adaptive variation to ensure that material is well-adapted to the planting site.

Group discussion suggested that breeders need to recognise the potential importance of local adaptation. Although the importance of very local adaptation is not supported by the results of recent provenance trials in birch, ash and oak.

Field visit

Delegates visited the Northmoor Trust’s forestry research site which is set aside for experimental work on forest species. FR, HRI and the Trust have all established experiments on this site. Six experiments were presented:

• Walnut combined provenance and progeny trial (Northmoor Trust)

• Walnut nurse and establishment trials (BIHIP Walnut group)

• Ash BSO (BIHIP Ash group)

• Beech provenance trial (FR under Concerted Action EU funding)

• Cherry, clonal trial (HRI)

• Ash provenance trial (FR with MAFF funding)

• Cherry, trial of micro-propagated material (HRI)

This report was considered by the FRCC at its meeting of 2 November 2000

January 2001