Forest genetic resources conservation in France: evaluation and prospects[13] (E. Teissier du Cros[14])

INTRODUCTION

“The close of the second millennium has been paralleled by mounting awareness of the impact of human activities on the environment. This has thrown into question practices dating from the dawn of the industrial era, and brought the issue onto the agenda of a number of recent international meetings (....) The 1990 Strasbourg meeting, in particular, proclaimed that European nations signatory to the conference agreed to implement forest genetic resource conservation policies on their territories. In France, the establishment of the Commission on Forest Genetic Resources by the Ministry of Agriculture in 1989, and the subsequent preparation of its relevant programme, gave concrete expression to this commitment”.

The groundwork for the gradual implementation of forest genetic resource policies in France over the past twelve years has involved a series of efforts to address this issue with a wide range of partners, including information, awareness-building and discussions, culminating in 1997 with the preparation of a National Charter which included the participation of many foresters in the public and private sector, as well as institutional partners. The Charter “proposes a framework for the organization of the national programme for the management and conservation of forest tree genetic resources”. A National Charter for the management of genetic resources published in 1999 covers in a more general way all living resources in the country.

This paper will briefly summarize the existing national conservation networks and their management, indicating a number of research and development prospects for subsequent action.

1. IN SITU AND EX SITU NATIONAL CONSERVATION NETWORKS

At least four forest genetic resource conservation methods can be listed (Teissier du Cros 2000).

• In situ conservation (Figures 1 and 2), for the main broadleaved social species, with conservation units subject to minimum management constraints. In the core area as in the surrounding isolation zone, planting with exotic resources of the same species, or with species that may hybridize with the species to be conserved, is not allowed (Steinmetz 1991).
• Dynamic ex situ conservation, adapted to scattered species: tree progenies are grouped by major regions, in an environment similar to the original environment. Sexual regeneration will be carried out.
• Static ex situ conservation for endangered species. These are basically collections of trees or populations to be vegetatively rejuvenated, but may also apply to low-temperature seed preservation.
• Dynamic ecosystem conservation, adapted to scattered species. Environmental (silvicultural) interventions may be necessary for some species to facilitate regeneration.

Figure 1. Example of an in situ conservation network: the beech (Fagus sylvatica) network. The map (Cemagref 1991) represents the 20 Provenance Regions and the approximately 180 stands classified for seed collection.

: 20 conservation units selected among stands classified as representative of the major types of beech stands.

: 7 stands selected under specific conditions: southern limits of French territory, timber line, twisted beech.

Operational networks

In situ:	Beech (Fagus sylvatica):	27 conservation units (forest plots)
	Silver fir (Abies alba):	18 conservation units (forest plots)
Dynamic ex situ:	Sweet cherry (Prunus avium):	2 conservation. units
Static ex situ:	Field elm (Ulmus minor):	300 trees
	Smooth elm (Ulmus laevis):	80 trees
	Mountain elm (Ulmus glabra):	30 trees
	Black poplar (Populus nigra):	400 trees
	Service-tree (Sorbus domestica):	106 trees

Networks now being established

In situ: Sessile oak (Quercus petraea): 20 (forest plots) conservation units

Norway spruce (Picea abies), Maritime pine (Pinus pinaster), Sweet cherry (Prunus avium), Mountain elm (Ulmus glabra) and Smooth elm (Ulmus laevis).

Wild service-tree (Sorbus torminalis)
Salzmann pine (Pinus nigra spp. salzmannii).

Under the aegis of the French Commission on Forest Genetic Resources, the question of existing conservation network management and blueprints for future networks has prompted a series of discussions concerning the size of conservation units and how to maintain their integrity and adaptability intact over a number of generations. These were based on a review of the existing literature on forest gene flows (Couvet et al. 1999) and on issues raised by the designers and managers of in situ networks. These discussions covered the following main points.

The goal of in situ conservation is to ensure the long-term adaptation potential of species or populations whilst leaving them free to evolve within their environments, thus allowing them to adapt to change. This means that our choices are dictated by the needs of future tree generations and populations, at least as we conceive them, as opposed to the needs of existing trees. To achieve this goal, the operational networks have three working objectives in common::

Objective 1: To ensure sufficient regeneration of the conservation network units by sexual reproduction,

Objective 2: Promote genetic diversity and structure such regeneration,

Objective 3: maintain the ecological and genetic characteristics of conservation network units over a number of generations.

Population genetic experts generally agree that the central or core conservation plot should contain at least 500 fruiting specimens in order to comply with the first two of the above objectives. Additionally, the core area must be surrounded by an isolation zone with the following three functions:

• to provide a pool of additional breeder trees to boost genetically efficient stocks
• to ensure a protective area to bar the introduction of an exogenous resource with respect to the target species
• to ensure that external seeds (and pollen, to a lesser extent) are filtered out.

As regeneration is a sensitive time in the life and cycle of a conservation unit, two issues arise:

• French silvicultural standards for even-aged stands stipulate a minimum number of breeder trees to regenerate a plot (60 mature trees/ha for common beeches and oaks). Is such a density sufficient to comply with objectives1 and 2 above?
• Blanket prevention of the introduction of exotic species or genotypes in the proximity of conservation plots is not materially possible. But might it not be possible to set a floor threshold for an acceptably small proportion of exogenic genes for compliance with objective 3?

For broad-leaved social species such as beech, oak and silver fir, the existing networks do seem to meet these objectives. The actual area of the core zone usually exceeds the specified 5 ha (Figure 2 shows a plot of over 16 ha, representing nearly 1000 breeding specimens). Considering the area of the peripheral isolation zone (comprising 218 ha in the example given in Figure 2), this makes thousands of specimens capable of interacting to contribute to regeneration in each conservation plot. The manager’s role in this case is therefore to ensure that the maximum number of breeder trees intervene during regeneration (this is not necessarily in contradiction with the fact that the manager’s role in a conventional plot is to ensure that the best specimens reproduce). As mature trees only rarely all fructify in the same year, it is strongly recommended that regeneration be staggered over several years of fruit formation where biologically applicable to the species.

Figure 2. A conservation unit in Eastern France: Haye State Forest, Nancy.

Hatched lines represent the core area (min. 5 ha, here 16 ha). The heavy black contour line represents the 218 ha isolation zone in which no exotic genotypes were established. The northern part of the core and several isolation plots suffered heavy damage in the December 1999 storms.

For pioneer species, such as black poplar Populus nigra along watercourses, for example, the thrust is ecosystem management at the protected site level - protected here does not mean not managed. The three above-mentioned objectives would be in addition to the other objectives inherent in such sites. However, the feasibility of this sort of multi-purpose management remains to be verified. Indeed a pioneer species like black poplar cannot maintain itself in the long-term without environmental disruption. It is up to the manager to rank the objectives of the protected area management or utilization plan over a given time-scale

For scattered species such as the wild service-tree (Sorbus torminalis - a pilot species[15]), the notion of the conservation site, and indeed the very concept of the network itself, need to be defined. A significantly large area - probably a whole stand or even a region - would need to be envisaged in order to obtain 500 breeder trees. It will be hard to achieve Objective 3 if exotic sources of wild service-trees are established in or near the stand. Were the plan to submit this species to the laws and regulations on forest tree propagation material, the area involved would certainly need to be parcelled out in order to limit transfers within France. In any case, further discussions on the subject are imperative, as are, in all likelihood, the consideration of more flexible solutions than for plots established for the social broad-leaved species, and more diversified management may also be needed.

Another interesting question came out of the forest destruction occasioned by the storms of December 1999. This was how to treat and regenerate in areas of such extensive destruction. The main criterion here is the number of breeder trees. Where they are too few, the next generation might well fail to meet our three objectives. In such a case, and this is what happened to the core of the conservation unit shown in Figure 2, one recommendation might be to eliminate the few remaining seed trees because each could well play an overly preponderant role in the composition of the succeeding generation, and allow surrounding seed trees to reproduce. Where the area of devastation is too vast, seed might be harvested from a belt around the core, which would be reconstituted by planting seedlings.

3. CONTRIBUTION OF THE SIGNATORIES TO THE CHARTER

The overall situation of forest genetic resources in mainland France is good. Early forest protection policies, environmental variety and the diversity of management styles have led to the maintenance of sizeable forest species diversity. Most of the existing conservation arrangements are in state or communal publicly-owned forests, which are managed within the departments of France by a public agency, the Office National des Forêts. This is a good guarantee of durability for conservation and long-term monitoring. The cooperation of the private sector (most of the forest owners in mainland France are private) is essential, however. Stand management is frequently more diversified in the private sector, thus providing access to specific resources which the even-aged and often single species forest stands cannot always provide. It is hard to find much broadleaf diversity in an even-aged stand of common beeches or oaks, for example. Such species are often sun-loving and less long-lived, and are severely handicapped when it comes time to regenerate or ensure silvicultural management, even where they receive more attention.

The fact that adhesion to the Charter and accordingly to the French national framework is voluntary gives it greater flexibility, making it easier for landowners and managers to assume their responsibilities. It should be pointed out that while major progress has been made in genetic conservation on the national level, forest managers are still rather uninformed about the need for it and the tools available to achieve it.

4. PROSPECTS

Twelve years of continuous activities in the domain of forest genetic resource conservation appear to have produced very positive results. Scientific and technical organizations have rallied, coordinating their efforts. Research programmes have been proposed and initiated, national and international funds established. The results of this research have clarified our understanding and produced new findings on gene flow and the genetic function of tree populations. Conservation networks have been established and others are set to follow. Joint study programmes on genetic diversity in tropical forests have been established, such as the Silvolab Scientific Interest Group in French Guiana.

But this positive beginning should not mask current or potential problems such as educational gaps in forestry studies, and the real risk that scientists, managers and government authorities lose interest because the subject becomes too routine or is seen as unprofitable. The need to consider genetic resource management as part of regular forest management also needs to be stressed. The question of how to integrate conservation and genetic-oriented concepts into public and private forest management plans needs to be addressed. Last of all, we have learned from experience not to compromise the future of resources whose commercial importance is not immediately apparent: species which are “not economically interesting” also deserve attention. Certainly, beech (Fagus sylvatica), wild service-tree (Sorbus torminalis) and yew (Taxus baccata) were not always considered noble and valuable species. All this is linked to the global concern for the conservation of biological diversity and the need to make the work of foresters and environmental protectors converge. The contribution of the protected areas and plots coming under the applications of the European directive “Natura 2000” has been only very partially explored to date.

Many scientific and technical questions remain unanswered. What is the long-term genetic function of a conservation unit? Which new model species deserve consideration? What is the true impact of plantations, in terms of potential genetic pollution of conservation units? How much does conservation cost, and what consideration should be given to the inherent constraints for the owner? Can the genetic conservation of several species on the same plot be reconciled, and, if so, how? These are some of the issues under study by the Commission on Forest Genetic Resources, which welcomes any suggestions.

FOR FURTHER INFORMATION

Bureau des Ressources génétiques, 1999. Charte nationale pour la gestion des ressources génétiques. Bureau des Ressources Génétiques. Paris. 99 pp.

Commission des Ressources Génétiques Forestières. Une charte pour la conservation des ressources génétiques des arbres forestiers, 1997. Bureau des Ressources Génétiques. Paris. 10 pp.

Couvet, D., Austerlitz, F., Brachet, S., Frascaria-Lacoste, N., Jung-Muller, B., Kremer, A., Streiff, R., 1999. Flux génique chez les arbres forestiers. Summary of the literature. 68 pp.

Démesure, B., Oddou, S., Le Guerroué, B., Lévèque L., Lamant T. & Vallance, M. 2000. L’Alisier torminal: une essence tropicale qui s’ignore? Bulletin technique de l’ONF, No 39, janvier 2000: 51-64.

Steinmetz, G., 1991. Les ressources génétiques forestières et leur protection. Rev. For. Fr. 43, n° spécial, 28-31.

Teissier du Cros, E., (Coordonnateur), 1999. Conserver les ressources génétiques forestières en France. Ministère de l’Agriculture et de la Pêche, Bureau des Ressources Génétiques, Commission des Ressources Génétiques Forestières, INRA-DIC, Paris, 60 pp.

Teissier du Cros, E., 2000. Un ensemble cohérent de références pour la gestion et la conservation des ressources génétiques forestières en France. Rev. For. Fr. 52(5): 391-400.