Developments during 2003 by Dr Peter Savill
During 2003 there have been several useful advances by BIHIP. Among them:
- Eight oak breeding seedling orchards were successfully established: one each in Wales, Scotland and the Republic of Ireland, and five in England.
- The Sycamore Group, under the Chairmanship of Michael Carey, has had its first meeting, and is now looking for stands, or individual trees of ‘elite’ sycamore trees. The group would be pleased to hear from any Woodland Heritage Journal reader who could help – contact Dr Carey at firstname.lastname@example.org.
- Generous financial support for the work of the various BIHIP groups has continued from the four main sponsors of recent years, the Forestry Commission, DEFRA, Woodland Heritage and the Royal Forestry Society.
- The Royal Forestry Society’s 2004 annual conference, on 4th March, will be on broadleaves and their improvement, entitled Better Trees, Better Profits. There will be an associated field day on 10 June at the Northmoor Trust’s site at Little Wittenham. BIHIP has had a considerable input into formulating the programme for the conference.
BIHIP species groups
BIHIP held its annual meeting and field day in the Huntley area of Gloucestershire and the Forest of Dean on 7th October. The day was organised by John Davis (BIHIP Treasurer) of Woodland Improvement of Conservation, and Rob Guest, Deputy Surveyor of the Forest of Dean. It was attended by almost 70 people interested in broadleaved tree improvement from all parts of Britain and Ireland. The day was devoted to discussing progress of the BIHIP Species Groups (except walnut) at a trial/experimental site of the species, or if no local trial was available, at a specimen of the tree. A general theme that came up several times during the day was expressions of regret at the official attitude to broadleaves, by the British forest policy makers, and more specifically English policy makers in the Forestry Commission. Current policy seems to focus on their amenity and recreational values. Little or no interest is shown in improving the quality of the resource, much to its detriment. The meeting agreed that more intense efforts to lobby officials and Ministers would be desirable and members of the Committee agreed that they would initiate appropriate action.
Karen Russell explained that cherry is the most advanced of the BIHIP groups, having started its work in 1989 at Horticulture Research International (HRI), before the establishment of BIHIP. The considerable experience of HRI at breeding sweet cherries provided the basis for the wild cherry research. The selected material that is currently being marketed as ‘Wildstar’ clones is in the process of being tested in trials for growth and other parameters. It is also being used for breeding in orchards. The group was shown a seed orchard, established by grafting 17 clones on to dwarfing rootstock in the mid 1990s, to encourage early flowering. Since clones are not self-compatible, a special planting design had to be used to encourage cross pollination. Enough seed is now being produced from this orchard to grow 7000 plants a year. A problem in collecting seed from cherries is that, unless great care is taken, birds and squirrels get them first. Therefore a multistage picking procedure has been developed to pick cherries just as they are turning from green to red.
Joanna Clark had recently finished a complete remeasurement of the original, 1993 ash breeding seedling orchards, and found that the relative growth rates of the different families has remained much the same as when last major assessment was made in 1998. In addition, she had collected some new leaf flushing data (which indicate frost susceptibility), and had also been able to record the sexes of the trees in one trial, since many are now beginning to flower. Ash can be a dioecious species and was described by Alan Mitchell as one in a state of “total sexual confusion”. The results proved puzzling. Of the 589 trees that had flowered in 2002, nine percent were female, 40% male and almost half hermaphrodite. The shortage of females may be a cause for concern when the orchard is thinned within the next few years, especially if the hermaphrodite trees do not produce very much seed.
The Oak Group completed its major task of establishing 8 breeding seedling orchards during the spring of 2003, thanks largely to the work of Gabriel Hemery and colleagues at the Northmoor Trust. Discussion centred mostly on the method of selection of the ‘plus’ trees. Oak is unusual among the BIHIP species in that after selecting on the basis of external characteristics such as form and branching, a timber characteristic was used as well. This was earlywood vessel size which has been shown to be related to a common defect, shake. Trees with large earlywood vessels are much more predisposed to shake than those with small vessels.
Rick Worrell explained that the Birch Group, unlike the others, had thought it wise to concentrate on provenance studies before embarking upon tree improvement work similar to the other Groups. This is because birch is known to be very sensitive to latitudinal movement, at least in terms of frost susceptibility. The studies have revealed significant differences between provenances in Scotland that roughly correlate with changes in environmental variables. The Group have now reached the point when they can collect scions from selected ‘plus’ trees. Two types of birch trees can commonly be found: smooth- and rough-barked trees. The latter give an attractive ‘flaming’ grain to the wood, but unfortunately, it is overwhelmingly the smooth-barked ones that provide the plus trees. A potential problem is that most of the selected trees originate from below 250 m in elevation, while the available planting sites are above this. To grow good birch trees of 30-35 cm dbh in 30 years, oak or ash sites are required. Birch is the easiest of all the species being dealt with by BIHIP. Grafted scions of plus trees in a polytunnel can be induced to produce seeds within a very few years. Progeny tests can be carried out quickly, and juvenile-mature correlations established. Once in production, a single polytunnel could produce sufficient seeds annually to satisfy far more than the whole British and Irish requirement for birch.
Michael Carey said that there are 60-70,000 ha of sycamore in Britain and Ireland. The first task of the Sycamore Group will be to establish a database of potential seed stands in the two countries. There was much discussion, led by Gavin Munro, about the importance of quality in sycamore timber; timber that had been properly pruned (not showing ‘cats’ paws’ on the stem) or with ‘green line’ in the wood. Sycamore is damaged more than almost any other species by grey squirrels, and Charles Dutton explained how to recognise a potential attack 2-3 years in the future by observing small ‘trial’ removals of bark from the stems, when squirrel densities are low.
James Johnston, Chairman of the Sweet Chestnut Group, outlined the plans for this group. They already have one seed orchard, established in Somerset, and further clonal seed orchards are planned, based on grafted scion material. Karen Russell and others in HRI will be involved in this project. Work has recently been completed at Imperial College (Wye) by Peter Buckley and a student on the susceptibility of sweet chestnut to shake. It is believed that essentially the same story applies as with oak, the other strongly ring porous species – trees with larger vessels have a greater predisposition to shake.
Dr Gabriel Hemery – BIHIP Secretary
Tel: 01865 407792