Dollar Tree rebounded in the stock market Wednesday after the specialty discounter topped Q4 forecasts and said it's well-placed to attract shoppers trading down in tough times. The operator of 4,671 stores in the U.S. and Canada earned $1.01 a share, up 26% vs. a year earlier, 2 cents above Wall Street estimates. Sales grew 15% to $2.25 billion, the best gain in years. Same-store sales rose 2.4%. Dollar Tree (DLTR) gave cautious Q1