Past and potential future use of hybrid poplars for wood production in Britain is considered, and preliminary results of trials with new clones imported from Belgium in 1985 are given. A series of nine field experiments established in 1991, to a common protocol, was analysed using stepwise multiple regression. The superior vigour of 'Beaupre' compared with 'Ghoy', 'Robusta' and 'Trichobel' was clear in almost every case. For 'Beaupre' (Populus trichocarpa X P. deltoides) altitude emerged as the

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... variable explaining most variation in tree height after six growing seasons, height declining with increasing altitude. The four best sites were characterized by low elevation and low rainfall. At the two older sites planted in 1987, at Ampthill and Bedgebury, the 'interamerican' hybrids (P. trichocarpa X P. deltoides) were the most vigorous, and the clones 'UnaP and 'Raspalje', which were thought to be too rust susceptible to release for commercial use in 1990, achieved similar stem sizes to those of 'Beaupre' and 'Bolelare'. The General Yield Class (based on a reference spacing of 8 X 8 m) calculated for 'Beaupre' was 8 at Ampthill and 24 at Bedgebury. Future prospects for poplar planting are considered in relation to possible reform of the Common Agricultural Policy.