UPDATE 2-Packaging Corp of America earnings beat estimates

* Q1 EPS of 25 cents beats estimate of 19 cents

* Sales down 11 pct

* Sees Q2 earnings below expectations.

* Stock up 12 pct in trading after the bell (Adds analyst comments, details, updates share movement,)

NEW YORK, April 20 (Reuters) - Packaging Corp of America (PKG.N) reported higher-than-expected first-quarter earnings on Monday, helped by lower costs, but forecast a second-quarter profit short Wall Street estimates.

Shares of the company rose 12 percent in trading after the bell.

"The stock is up because people like the earnings -- because of this beat it might add a few cents to people's full-year earnings estimates," analyst Joshua Zaret of Longbow Research told Reuters.

Net income in the quarter fell to $26 million, or 25 cents a share, from $32 million, or 31 cents a share, a year ago.

Net sales dropped 11 percent to $512 million.