Working Party on Logging and Utilization of Poplar and Willow Wood
This is the oldest working party of the IPC, whose establishment dates from the early 1950's. It brings together all experts interested in the question of logging and utilisation of poplar and willow wood.
For each member country, the meeting has been an opportunity to sum up and report on progress achieved and on research underway. Moreover, the working party has drawn up a standard form for technological trials which is intended to describe and qualify the wood of the cultivars used by member countries. The working party has also dealt with felling and harvesting practices and with developing new possibilities for wood utilisation.
Economic problems have not been ignored by the working party; on the contrary, data have periodically been gathered and submitted to IPC sessions, thus making it possible to monitor the evolution of cultivated areas, volumes utilised, and operating costs and prices.
Recent work of the working party has indicated that the trend in harvesting is now to use all-tree harvesters in plantations, and specially constructed machinery for short rotation biomass plantations. This has confirmed that the outputs of research are filtering down to the operator.
The trends in wood products have been influenced by the need to reduce waste. Traditional uses have remained important but high value products will likely to be more actively marketed in the future and research will, therefore, be important in the coming decade.
With regard to the aims of poplar breeding, it has been the opinion of some in this working party that breeders should aim at producing trees with high density and straight form, apart from resistance to pests and diseases. Others maintain that breeders should endeavour to produce trees that would satisfy a variety of industrial requirements.
Recent working party discussions have included the effect of management regimes, large-scale industrial projects, and the benefits of combinations with agricultural crops or grazing. In this context, the role of poplar growing on "set aside" farmland in the EEC has been discussed, together with the uses of computer modelling in such situations. Member countries have been invited to pay more attention to the environmental aspects of poplar and willow growing, as well as to the recycling of products. The need for greater co-ordination between the growers and those who use the wood of poplar and willow has been stressed.
The working party has recommended that more joint sessions should be held between the different working parties of the IPC in future, in order to achieve greater co-ordination of research and development and the transfer of technology. It has proposed that mechanisms should be developed for the greater involvement of the private sector in its future activities, and has recommended that the Executive Committee should investigate ways of promoting student exchanges and participation in meetings of the working parties.
The following three research priorities were identified in 1996: wetwood, tensionwood, and biodeterioration and its prevention. The working party also identified the subject matter for three technical leaflets, to be prepared by its members and passed to the Secretariat: economics and the modelling of poplar production; production, technical characteristics, and the utilisation of willows; production, technical characteristics, and the utilisation of poplars.
Working Party on Poplar and Willow Diseases
This Working Party has met regularly since its first meeting in Paris in April 1957, with attendance mainly by pathologists. Each meeting has served to exchange information about the health conditions of poplar and willow plantations in the member countries and about the work done and the results of research. An overview paper describing the activities of the working party since its formation was presented by the chairman in 1992.
A subject has been proposed to the participants at each meeting so that discussion can quickly concentrate on a common field. Joint research programmes have been agreed between pathology laboratories where mention may be made of international arrangements for studying the susceptibility of cultivars to Marssonina brunnea and a research programme on sensitivity to Xanthomonas populi. In carrying out these programmes, pathologists have helped one another, exchanging information, techniques and sometimes their material. They have received visiting researchers who can then familiarise themselves with the methods applied. In this way knowledge of poplar and willow diseases has made rapid strides towards their control.
Apart from summary reports on the meetings, with the texts of the communications presented in an annex providing a wealth of documentation, the working party in 1981 completed a synthesis which was published under the French title "Les maladies du peuplier" (Poplar Diseases) by the National Forestry Fund set up in 1946 by France.
The leaf diseases (Marssonina brunnea) and, in particular, the rust diseases (Melampsora spp.) have continued to be a major cause for loss of vigour in the poplar plantations. Because of the high variability of the diseases, work has had to concentrate on their taxonomy. The bark parasite, Dothichiza populea, which is also highly variable, has caused increasing concern to affected countries.
The gravity of risk of virus diseases was recently highlighted by the working party. Though damage attributed to air pollution may be caused primarily by physiological stress, a suggestion was made at one of the last meetings of the working party that it should become involved with this topic.
The sensitivity of 78 clones of European origin to Marssonina brunnea was tested in France. As there was a certain divergence among the findings obtained in a number of countries, the working party has been endeavouring to find satisfactory explanations in the context of international co-operation.
The working party has repeatedly drawn attention to the existence of physiological races of Melampsora larici-populina and M. allii-populina and to the rapid evolution of populations of these races; although it was acknowledged that progress has been made in understanding the reaction of clones and species of poplar to the diseases, it has been stressed that more attention should be paid to the selection of clones for resistance to both pathogens. A strategy has been described for the utilisation of white poplar, involving the selection of families and provenances for tolerance to frost and drought.
It has been recommended that the collaboration between tree breeders and pathologists should be expanded and should be translated into some joint sessions. Two joint projects were prepared in 1994 with the Working Party on Poplar Insect Pests. The first would aim to acquire systematic knowledge on the natural resistance mechanisms of poplars and willows towards insects and diseases. The second would look for possible correlations between tree susceptibility and soil characteristics or other ecological factors, in order to determine the risk of damage by insects or diseases to a particular poplar or willow for a given site.
The following recommendations were made in 1996 for future activities:
- the preparation of a world map of the principal diseases of poplars;
- the extension of existing collaboration with the European Union in the evaluation of the reaction of existing clones of poplars to the main diseases to other countries and continents, harmonising the results to make them comparable;
- the preparation of a detailed study of the diversity of the two pathogens Marssonina brunnea and Discoporium populeum.
Once again potential problems arising from the transfer of diseases from one continent to another were identified as being of high importance.
Working Party on Poplar and Willow Insect Pests
This working party was created in 1957 after a number of Belgian, Dutch, French, Italian, and Spanish entomologists met in Paris. They pointed out the potentially harmful significance of insects, mainly xylophagous ones, to the development of modern poplar and willow cultivation and suggested that the IPC set up a working party on pests, along the lines of the Working Party on Poplar Diseases. Since its establishment, the working party has operated regularly under conditions comparable to those of the Working Party on Diseases, in the same spirit and with the same goals.
Except for the presence of a new pest recorded from France (Anisandrus dispar) and the problems arising from associations between poplars and agricultural crops, there have been no serious attack by new insect pests for several years. In Europe, the most harmful insects continue to be primarily borers such as Cryptorrynchus lapathi, Saperda carcharias, and Paranthrene tabaniformis. In Argentina, considerable damage is being attributed to defoliating insects (Nematus desantisi and Hylesia nigricans), a sucker (Pterocomma populea), and a borer (Platypus sulcatus); rodent damage to young plantations has also been reported.
The working party has foreseen that the trend in phytosanitary protection of poplars and willows towards the year 2000 will be noticeable for the increased use of biological control methods (for instance, preparations based on Bacillus thuringiensis have been increasingly used for the control of Lepidoptera, and the control of Cryptorrynchus lapathi by nematodes), the breeding of pest resistant clones, and the increased use of environmentally less harmful insecticides (such as those containing diflubenzuron).
Whether the enlargement of the genetic base of the planting material and the reduction of the risk factor could be better achieved by planting clones in mixtures or through a mosaic of monoclonal plantations has been debated by the working party, which has also drawn attention to the need to increase basic research on resistance of the Salicaceae to pest damage. It has recommended that interdisciplinary work aimed at genetic improvement should be increased as well.
The choice of clones to be planted in a given environment has to be based not only on short-term economic considerations of fast growth but also on the need to satisfy other requirements, such as the maintenance of genetic diversity. By so doing, better protection will be offered against biotic or abiotic risks and better adaptation to local variability of the site.
Recommendations on guidelines for its future activities were adopted in 1996 as follows:
An overview of internationally important insect pest of poplars has been prepared, the results of an enquiry conducted among member countries in 1993.
Working Party on Poplar and Willow Breeding and Selection
On the basis of work done by pathologists and, to a lesser extent by entomologists, which brought out the hereditary character of susceptibility and resistance to diseases and to some insects such as Phloeomyzus passerinii, poplar breeders felt the need of setting up a structure of their own for co-ordination and co-operation which would open up great possibilities for the biological control of certain poplar enemies. Up to that time, breeders had confined themselves to taking part in the activities of the Working Party on Diseases and to closely observing the research results of pathologists concerning variability in the reaction of cultivated poplars to pathogens. Systematic work done mainly in Belgium on the hereditability of certain genetic characters showed that poplar genetics ought to have its place among the concerns of the IPC, which therefore agreed to the establishment of the new subsidiary body in 1971.
Some important activities may be mentioned. On the one hand, thanks to co-operation and close liaison with the Poplar Council of the United States of America, in the late 1960's/early 1970's several collections of seed from various sources of Populus deltoides and P. trichocarpa were subsequently distributed to European countries involved in research programmes concerning those species. On the other hand, thanks to a generous offer from the Academy of Forest Science of the People's Republic of China, the first collection of propagation material from various sources of P. maximowiczii, P. simonii and P. yunnanensis was distributed widely among member countries in the early 1980's. These undertakings were significant examples of the spirit of international co-operation that has always characterised the IPC member countries. By leading to the creation of new hybrids, they have been harbingers of a veritable revolution that has the potential to improve poplar and willow cultivation in several countries; one should not, however, underestimate the risk of spreading diseases through the exchange of material, and close liaison with pathologists must not be relaxed.
Pathogens and insects have in fact been transferred together with the germplasm, as happened with the introduction of leaf rusts (Melampsora spp.) to Australia, New Zealand, Argentina and South Africa, of the poplar mosaic virus to China, and of Septoria musiva to Argentina.
The working party has also drawn attention to the fact that the populations of some native species were rapidly disappearing, either because they were displaced by agriculture or other land uses, or because they spontaneously hybridise with cultivars. Natural stands of Populus nigra have almost disappeared in Europe and the situation for P. deltoides in North America has become very serious. Studies in China on the natural range and individual variability have been underway for a number of species, amongst which P. tomentosa deserves special attention.
The main activities in central, western and southern Europe have been focused on the creation of Euramerican or inter-American hybrids; the selection objectives have primarily concerned the search for satisfactory resistance to parasites, and environmental adaptation. Modern techniques of controlled cross-breeding have been used. In northern Europe the main research topics are vegetative multiplication and the development of multiclonal varieties of aspens, which have been widely used. Willow breeding has been very important in Argentina; the main focus there has been improved resistance to both parasites and flooding.
Early in the 1990's the working party decided to concentrate on the following topics: (a) the potential of biotechnology in poplar breeding, (b) poplar breeding for extensive culture, (c) status and perspectives of North American poplar resources, (d) breeding of Asiatic willows. It also recommended that FAO should address to member and non-member countries a formal invitation to adopt appropriate measures to ensure that existing genetic resources of poplar and willow species, in natural and man-made stands be properly preserved, stressing the role that fast-growing species may play in reducing the pressure on delicate and endangered natural environments world-wide. Member countries were invited to design model programmes around Populus deltoides and P. nigra in consideration of their great importance in breeding programmes and the existing threats of genetic pollution from cultivated varieties.
The following recommendations were made in 1994:
As for needs concerning Populus euphratica, the working party recommended in 1994 the enlargement of fundamental knowledge, particularly in the field of its ecology, physiology, and genetics; the conservation of natural stands in areas where they are diminishing seriously; the establishment of at least one Populetum euphraticum for in situ conservation; the preparation of a monograph on the species. Subsequently, the working party acknowledged the action taken by FAO on monitoring the status of Populus euphratica and P. ilicifolia. It recommended that a similar effort be extended to other low-latitude species adapted to the warm and dry climates of many sub-tropical countries, especially P. yunnanensis and P. ciliata in Asia and species of the Aigeiros, Abaso, and Tacamahaca section of poplars in Mexico.
In 1996 the working party recommended that special attention should be devoted by member countries with long experience in poplar and willow breeding to the transfer of knowledge to countries where such culture was relatively new. Some of the germplasm grown in ex situ collections might no longer be used in one country but might be still useful in another, and it therefore recommended that member countries maintained such collections. The attention of member countries was drawn to the ongoing debate on breeders' and farmers' rights while in view of the nature of breeding programmes for improved wood production and other benefits, the working party drew the attention of member countries to the need for long-term commitment of adequate funding.
Working Party on Production Systems for Poplars and Willows
(formerly, Working Party on Biomass Production Systems for the Salicaceae)
This group, set up at the XVI Session in 1980, aims to promote co-ordination among specialists concerned with biomass production from poplars and willows. As this was a totally novel kind of cultivation, so far as techniques of cultivation, choice of cultivars, and harvesting techniques were concerned, it was decided to assign these problems to a new group rather than splitting the study among the existing working parties. The specialised new group has thus been in a better position to maintain relations with institutions pursuing similar objectives, such as the International energy Agency (IEA) and the Research Units of the International Union of Forestry Research Organizations (IUFRO).
The first formal meeting of the new group was held on the occasion of the XVII IUFRO World Congress in Japan in September 1981. Since then, biomass production in dense, short-rotation plantations of poplars and willows (including agroforestry systems with complete utilisation of the combined biomass), regenerated by coppicing, has been introduced on an experimental scale in Canada, France, Belgium, Sweden and USA. Trials on a small scale have been conducted in Austria, China, Hungary, Ireland, Italy, New Zealand, Pakistan, Turkey and UK
The work programme 1984-88 of the working party included a proposal for a poplar biomass project in China, the development of a manual for biomass production, the development of a database, standards for biomass qualities, and the publishing of a woody biomass terminology.
At its session in 1992, the participants agreed on the integrated approach being adopted in consideration of the short rotations of biomass systems as well as on the importance of socio-economics and market analysis. They also noted the lack of a working party of the IPC devoted to management systems of poplar and willow plantations and suggested the broadening of scope of the working party.
A cost-benefit analysis of biomass production systems compared to other land uses has been initiated in Turkey and the results will be of wider interest to working party members.
It was recommended in 1994 that a report be prepared on the modelling of production system in the Salicaceae. The importance of poplars and willows to social forestry, which should be regarded as multipurpose species, was recognised and member countries were encouraged to investigate the opportunities for technical assistance to support such programmes. It was further recommended that activities of the working party should include studies of the specific requirements for the growth of poplars and willows in the more northerly regions, including Scandinavia, and the northern parts of North America and China.
