Article

Wild stands of Populus nigra L. can be considered on the verge or extinction in a large part of western Europe. Its natural habitat is being gradually reduced by human activity and the gene pool is threatened by the large-scale presence of c ulti vated hybrids and of one ornamental .' cultivar, the fastigiate ' Lombardy poplar', that spontaneously hybridize with P. nigra. Although cultivars of P. nigra are cultivated in some areas, especially in the Middle East, the main use of this spec ies is as a parent of interspecifìc hybrids in breeding programmes. From an economic point or view the most important hybrid combination is produced by using P. nigra as a pollen parent and with the North American P. deltoides Bartr. as the seed parent, resulting in the common 'euramerican' hybrids (P. euramericana (Dode) Guinier). Some varieties of black poplar are al so widely used for their ornamental qualities. This represents an originaI ex ampIe of a wildlcultivated complex pool in rorestry. The conservation of in Situ genetic resources is limited to some restricted areas, such as the riparian fore sts, typical habitat or P. nigra, which have suffered considerably from urbanization, industri ali zation and competition with human productive activities. Ex situ conservation activities, on the other hand, have been carried out in several European countries. A project for the coordination of efforts airned at the conservation of P. nigra has been recently launched as one of four pilot projects included in the European Forest Genetic ResoUfces Programme (EUFORGEN).