J.F. Lacaze
J.F. LACAZE is Director of the Forestry Research Centre of Orleans, France.
During the past ten years numerous projects have been put into operation, very often on the basis of international collaboration. In this connection special mention should be made of the excellent work done by various bodies such as the IUFRO working groups on provenance seed collection of North American species, FAO (Committee on the Coordination of Mediterranean Forestry Research), the Commonwealth Forestry Institute, the Danish/FAO Forest Tree Seed Centre and the Centre technique forestier tropical (France).
The number of species on which provenance trials are conducted is very high; just as examples, we can list:
· For species concerning temperate zones: Abies grandis, Picea abies, Picea sitchensis, Pinus contorta, Pseudotsuga menziesii, Larix europaea and Populus trichocarpa.· For species concerning Mediterranean zones: Pinus halepensis, Pinus brutia, Eucalyptus camaldulensis and Eucalyptus dalrympleana.
· For species concerning subtropical and tropical zones: Cedrela odorata, Eucalyptus alba, E. camaldulensis, E. deglupta, E. microtheca, E. tereticornis, E. urophylla, Pinus caribaea, P. kesiya, P. oocarpa, P. pseudostrobus, Tectona grandis, Terminalia ivorensis and T. superba.
In most cases the species studied are exotic to the country in which the experiments are being conducted.
The transfer of forest reproductive material, throughout the world, has reached unprecedented heights during the past few decades; many countries have been trying to intensify their forest production by introducing new species or provenances.
At the same time, there has been an increase in organized research aimed at supplying silviculturists with objective information on the vegetative material to be selected.
An effort on this scale is inconceivable without active international cooperation. Some progress has been achieved, but much remains to be done in this field.
We shall not refer to the definitions of standard terms such as "native" or "introduced species", "provenances", etc., which were fully clarified at previous consultations.
Suffice to recall that, in most cases, species and provenance selection programmes have an economic purpose: the improvement of forest products in both quantity and quality. There are many examples of spectacular successes, but failures have also been recorded - sometimes on a large scale when the basic experimentation has been wanting.
One should also think of objectives less connected with the production of timber, such as selecting species or provenances for diversifying the forest flora, with the intention, for example, of protecting or establishing recreation forests. These concerns are, in fact, receiving increasing attention in a number of countries.
This type of selection constitutes the first selection to be made in any programme of genetic improvement. It consists of selecting from among the existing wild material, either within natural stands or in plantations, on the basis of inter- and intra-specific variability.
At first sight, this type of selection might appear to be less advanced than that which is based on individual variation, but in most cases it proves to be absolutely indispensable. We shall present a few of the arguments supporting this view.
The selection of species and provenances often constitutes an absolute prerequisite to any programme of individual selection. In fact, there is reason to doubt the effectiveness of a breeding programme based on parent stock chosen from a population (species, provenance) that is itself genetically inferior. Moreover, it is impossible to ascertain the best provenance of the best species for all sites in the world, but we can state that for several large reforestation zones it has been possible to identify, for several forest species, a certain number of populations of unquestionable genetic superiority (for example, for the species: Pseudotsuga menziesii, Picea abies, Eucalyptus camaldulensis, Cupressus lusitanica, etc.).
Sometimes the provenance selection programme makes it possible to go further and to estimate certain genetic parameters (and their intra-specific variation), such as the heritability or genetic correlation of the main characters, and this again helps to facilitate procedures during the subsequent stages of genetic improvement. In order to attain these objectives, it is necessary for the provenances to be represented by a certain number of descendants kept separate and 'clearly identified within the experimental plots.
If suitably conceived, a species and provenance selection programme can supply information leading to interesting results of a fundamental nature on the following points, among others:
· Requirements of the species· Laws of variation, in particular, explanation of genetic variation resulting from the selection pressure exerted by variations in environmental factors
· Genotype-environment interactions
· Evolution of the species, effect of selection pressure, and so on
Forest species (wild, perennial, wide-ranging) constitute excellent material for genecological studies.
The transfer of species leads to the creation of new populations (land races) thanks to the effect of selection pressure in the zones where they are introduced. It is already known that certain of these land races constitute excellent sources of seed for the region concerned (Douglas fir in Europe, Cupressus lusitanica in Africa, etc.). These "new gene pools" often deserve to be conserved and multiplied.
Nevertheless, experience shows that land races are not always the best. Thus, teak introduced into West Africa several generations ago is proving to be inferior to certain provenances from the species' natural range.
There is no doubt that the essential objective of species and provenance selection is to enable silviculturists to achieve an appreciable improvement in wood production.
A list of the successes obtained would be very long. The potential profit to be gained from the utilization of good provenances of interesting new species is considerable, it is quite feasible to aim at a doubling of production by this means. It should be noted, however, that enormous advances still have to be made.
Field trials, that is, establishment of comparative trial plots replicated on a number of sites, still seem to constitute a really indispensable experimental tool. The trial plots are installed in the middle of the reforestation areas concerned; they make it possible to compare genetic variation with ecological variation, which means that the greater the number of sites involved, the more effectual are the trials.
In addition to field trials, recourse can also be made to such new techniques as the use of biochemical criteria in setting up varietal tests or demonstrating the laws of intra-specific variation. Progress in this direction has been registered recently for species such as Pinus sylvestris, Pinus nigra, Picea abies, Pinus pinaster, through the analysis of enzymatic systems or terpenes. But despite the attraction and interest of these new methodologies, it would be imprudent to abandon field trials. In the present state of our knowledge, these are the only tests able to meet the specific requirements of forest trees, in view of their longevity and of the fluctuations in environmental conditions over the years that characterize many stations.
FIELD TRIALS IN SOUTHEAST ASIA looking for genetic variation
The criteria taken into account concern mainly the growth and shape of the trees of the various species or provenances tested. It is indispensable to enlarge the list of these criteria, by examining more particularly the quality of the wood, as well as any characteristic helping to explain the behaviour and adaptation of the plant material studied. The list could include both phenological observations and analyses of pests or parasitic fungi.
One should not limit oneself, in fact, to noting the differences between provenances and species; an effort should be made to try and explain them (laws of variability), thus making it possible at a later stage to reduce the number of plots and in particular the number of provenances to be included in comparative field plots.
It should be noted that some of the more recent projects entail a very large number of provenances (up to one thousand), whence the necessity of using experimental plans with very small unit plots (including some with only one tree). The management and analysis of these designs could very rapidly pose problems which should be examined very carefully.
Finally, it should be pointed out that the idea of provenance has so far been applied essentially to social species. It should now be extended to species scattered throughout mixtures of other species. This problem regards many tropical species as much as some valuable species from the temperate regions.
The main stages in a species or provenance selection project are known. They are recalled briefly below.
Up to the 1960s, one of the major obstacles to the development of research programmes lay in the impossibility of obtaining reproduction material (seeds, cuttings) collected from natural or man-made forests suitably checked by sampling. For too long these studies were carried out using seeds obtained from botanical collections, or even of unknown provenance.
We have seen that over the last 10 years or so, enormous progress teas been made in this field, in particular thanks to the organization of cooperative projects. In some cases, the research organizations concerned have to devote a considerable part of their resources to setting up the field trials with the numerous batches of seeds already collected.
ARAB WOMEN TENDING AN EXPERIMENTAL DRY-LAND NURSERY breeding to suit the environment
However, two new types of requirements are appearing:
· The first results of the trials make it possible to identify the good provenance regions, the desire to obtain new batches of seeds on the basis of more intensive selection in these favoured zones.· Some countries wish to enlarge the list of species to be taken into consideration, including in particular tropical hardwoods of potential interest and species utilizable in arid and semiarid regions. In the latter case, the aim is not always the production of wood: the provision of fodder and protection (including protection against wind) may have priority. A new list of species has recently been drawn up by the FAO Panel of Experts on Forest Gene Resources.
The many experimental plots (past and future) set up using material collected within the framework of international efforts are or should be analysed in a cooperative manner. This entails an effort of coordination at all stages:
· Establishment of experimental designs which are, if not identical, at least comparable with each other in the various zones or countries.· Development and utilization of identical procedures for measurement and observation. A particular effort should be devoted to the methodology of observations on phenological stages, pest and disease damage, and measurements of wood quality.
· Establishment of coordinated timetables for measurements and observations.
· Utilization of modern means of data processing, at least at regional level.
It is recognized that this way of proceeding makes it possible to improve considerably the effectiveness of the experiments set up, which are usually very expensive.
In addition to the possibility of checking the results of each experiment against those obtained in all the others, this method also has the advantage of making it possible to estimate the effects of the interaction between genotype and environment and to identify "plastic" populations, i.e., those adaptable to a large variety of ecological situations.
In addition, such coordinated action also has the great merit of enabling countries or regions with limited research, infrastructures or equipment to benefit from the resources available and the experience acquired in other countries.
Recent examples have demonstrated the effectiveness of the assistance that can be provided through the implementation of programmes of this kind.
Finally, these examples (Picea sitchensis project, Eucalyptus camaldulensis, tropical pines, etc.) have shown that the undertaking is possible when a certain number of conditions are fulfilled. Two of these seem essential:
· People or teams must be found who are able to get the project moving. In some cases this is a fairly demanding task, calling for everything from field visits to discussions with those responsible for the project at national level.· The responsible national personnel cooperating in the projects must accept a certain degree of discipline and follow the rules of the game proposed by the project leaders.
A rapidly increasing mass of reference material is available in this field of research, to the extent that national bodies which do not possess specialized documentation services may experience a certain amount of difficulty in selecting the most useful information.
At the level of each international project, the leaders are able to facilitate transmission of the results from the various trials.
In countries where there are a considerable number of programmes for species and provenance trials and conservation plantations, it is suggested that simple catalogues be prepared on the work done and the results achieved, for exchange between specialists.
Finally, at world level, a publication such as Forest Genetic Resources Information, edited by FAO, constitutes an interesting initiative for diffusing the most impressive results of the main programmes.
We have already emphasized the importance of the practical repercussions of species and provenance selection programmes.
It is still necessary, however, for silviculturists to be able to find on the market reproductive material selection through experimentation. Despite certain recent advances (OECD Scheme), the situation does not appear to be very satisfactory.
In fact, the system of collection and control is the responsibility of each individual country and the first concern of the national authorities is with internal supplies. Any external customer encounters difficulties in obtaining commercial quantities of seeds when specific sources are required. The OECD Scheme is, by definition, strictly voluntary and cannot be coercive.
In order to resolve this problem, at least in the future, it is suggested that networks of plantations for the conservation of provenances be set up on a regional basis, with the following three main roles:
· Supplying the region with reproduction material.
· Providing a source of individual selection for future improvement programmes.
· Conserving gene pools.
This action could be undertaken or pursued in conjunction with those to which reference is made within the framework of session 1, "Exploration, utilization and conservation of gene resources", and in conformity with the recommendations of the FAO Panel of Experts on Forest Gene Resources.
The recent development of techniques of floral induction could reduce the delays encountered in obtaining seeds.
Collaboration at the international level may prove to be necessary here.
Great advances in species and provenance selection have been made during recent years, in particular thanks to the development of international cooperation.
These advances will result in an improvement in the effectiveness of reforestation work, mainly from the economic point of view. It is to be hoped that these research programmes will be conducted and analysed in such a way as to cover the greatest number of countries and supply the maximum amount of information useful for forestry.
