Some 3,000 workers at Finnish forestry group UPM went on strike on Saturday, shutting plants, the company said on Saturday. Three unions representing paper workers, managerial staff and electricians had previously warned they would strike if a new agreement about wages and working conditions was not reached before the previous agreement ended on Dec. 31.  The strikes do not concern UPM Plywood and UPM Timber, both of which signed business specific collective agreements with the Industrial Union in December. UPM quit collective bargaining a year ago together with other forestry employers, saying the industry ...