Wood is man's oldest material; it is also becoming one of the most expensive. Timber cost Britain £1,200-million last year; by the end of the century it could be twice as much. Already it is our third biggest import and prices have soared. Even a pencil costing 3½p four years ago, today costs double. Wood, after years of neglect, is needed again - desperately. But the forests of the world cannot cope.

Tonight's "Horizon" looks at what possibilities are left to us in Britain. Can we afford to be fussy about environment and landscape problems at a time like this? Should we be growing more or less timber at home? Can the enormous expertise of British Forestry help? Forestry is a long-term business; every tree needed in the year 2000 is already in the ground. Horizon asks if it is already too late to prevent a world timber crisis.