METALS-London copper sheds early gains as dollar firms, trade concerns linger

(Adds analyst comment, updates prices) BEIJING, March 28 (Reuters) - London copper gave up early gains to trade down slightly on Wednesday, tracking a decline in equities on a firmer U.S. dollar and as global trade tensions persisted. The dollar index, which gained about 0.3 percent overnight making metals more expensive for holders of other currencies and weighing on prices, was trading flat at 0500 GMT. However, markets are less volatile now and fluctuations in the base metals wer