Policies and practices
Poplars and willows largely occur naturally on river banks and marshy places and the fastest-growing, and most profitable, plantations have been established in these sites. Environmental issues and public concern regarding the alteration of natural riparian habitats and flood plains through the establishment of plantations have strongly affected policies and practices in both poplar and willow culture in many countries in North America and Europe.
Some changes in national policies and legislation, mainly concerning new regulations for forest reproductive material, the registration of new clones, natural forest protective projects, financial incentives and measures to preserve the quality of the environment were reported. The application and development of EC Regulation 2080/92 was substituted by EC Regulation 1257/99 that provided for approximately the same subsidies; poplar cultivation will therefore be financially supported in the European Union until 2006.
In East Europe the forestry sector, as with other economic activities, has continued to adapt to free market conditions. Some countries, as Hungary, Romania and Bulgaria, introduced regulations regarding the restitution of agricultural and forest lands to their former owners.
Most countries carried out research in various topics, including tree breeding, the use of poplars and willows for energy and for phytoremediation and the control of pests.
Interest in the use of poplar and willow for energy was strongly maintained in countries such as Sweden (mainly willows), Yugoslavia, Croatia and the United Kingdom (where an energy crop scheme for poplar and willow planting has been carried out). Another new development has been in phytoremediation, where poplars or willows are planted as vegetation filters on wastewater and landfill leachate sites or other polluted sites. The use of willows for this purpose is being pioneered in Sweden since they have a high "filtering capacity" to take up nutrients such as nitrogen and also heavy metals such as cadmium.
The incidence of pests and diseases is very high in plantations of poplar, to a great extent due to intensive breeding for characters associated with production which has led to reduced natural resistance.
Poplar (Populus tremuloides) in flower
(Photo: J. Worrall)Tree breeding is more advanced in the poplars than in any other forest tree group and interest in genetic engineering and marker-aided selection programmes has continued to increase. Poplar genetic maps are available or in an advanced stage of development in some countries. Efforts are concentrating on breeding not only for improved characteristics associated with production such as fibre quality but also for herbicide tolerance, flowering control and resistance to insect and disease attacks. An article making the case for the use of genetically modified poplars is "Genetically modified poplars in context" by Strauss et al., Forestry Chronicle 77 (2): 271-279.
The use of biotechnology in crop improvement has been controversial (see FAO's statement on biotechnology in food and agriculture and Description of biotechnology in the forest sector).
The basis of a successful tree breeding programme is the conservation of wild populations of poplar and willow species. The need to protect willow genetic resources by in situ and ex situ means, was confirmed by various countries. Most European countries reported their participation in the EUFORGEN Programme for the conservation of native stands of Black poplar, Populus nigra, with valuable progress made in the conservation and understanding of the genetic diversity of this species. A database with information regarding the origin and the conservation of P. nigra clones included in the ex situ collections found in various European countries is being prepared. Nineteen countries have already supplied information for the creation of such a database and 2 800 clones have been registered (a full description is in Black poplar: a model for gene resource conservation in forest ecosystems, by Lefevre et al. Forestry Chronicle 77 (2): 239-244). Recognition of the need for the conservation of poplar genetic resources as the basis for tree breeding programmes has not however, been confined to Europe (see for example a description of work in China by Zili et al. 1999. Poplar genetic resources in North China: the challenge of sustainable forestry, Forest Genetic Resources 27: 1-12).
Several national commissions carried out activities such as meetings, technical presentations, preparation of Web sites, study tours, etc. Canada, which continues to be one of the most active, has developed the potential of electronic communication and dissemination of information. On occasions, national commissions have had important roles in official discussions of strategies for poplar and willow cultivation. In general, good communication and cooperation in joint activities related to the exchange of information and materials were observed, particularly between countries of the same geographical region.