The strikes at UPM Plywood, the company's plywood production plants, are set to continue. The Finnish Industrial Federation issued its fifth strike warning today – the strike would begin, or rather continue, at UPM Plywood's four Finnish units on Monday 31 March and end on Sunday 6 April.    Strikes at UPM began in early March and have continued ever since. Strikes are also planned for next week and the following week, unless an agreement is reached before then.    The company has plywood factories in Ristiina, Savonlinna, Kouvola and Joensuu.   ...