President Donald Trump’s decision to withdraw from Trans-Pacific Partnership trade negotiations could drag down exports from Silicon Valley and California’s farm belt, trade experts said Monday. Trump signed an executive order Monday ending the United States’ participation in TPP talks, reversing former President Barack Obama’s commitment to executing the wide-ranging trade deal. The pact involved 12 countries bordering the Pacific Ocean, including Mexico, Canada, Japan, Australia, New Zealand, Vietnam, Chile and Peru. It would have gradually eliminated as many as 18,000 different tariffs on goods traded among the countries, and promised cooperation on broader employment practices. “I think it’s calamitous for California,” said Jock O’Connell, a Sacramento economist and international trade consultant. He said the TPP would have helped California farmers, tech and biotech manufacturers, the film and music industries and other exporters.