Thousands of Polish farmers Friday staged blockades at 250 locations and blocked border crossings into Ukraine to protest European Union climate change measures and the flow of agricultural goods into the country. Polish media and video on social media showed long lines of tractors at several border crossings with Ukraine and on highways around cities throughout the country. The nation’s Polsat news channel reported that police in Warsaw issued traffic warnings for much of the nation, particularly at the Ukraine border. In Poznan, about 300 kilometers (186 miles) west of Warsaw, farmers parked about 1,000 tractors in front of the regional government offices. Poland’s farmers union said Friday’s actions kick off a monthlong general strike. The Polish farmers join a wider series of protests by their counterparts around Europe in recent weeks, including in Germany, France, Romania, Greece, Lithuania, Belgium and Latvia. While Poland joins farmers from those nations in protesting the EU-imposed environmental regulations, Poland’s farmers union and agricultural leaders say they have been hurt in particular by the flow of cheaper goods coming …