STAMFORD, Conn. — Champion International Corp. said Tuesday its earnings plunged 86 percent in the third quarter because of low paper prices.

Earnings were $32 million, or 33 cents per share for the quarter ending September 30, down from $235.6 million, or $2.47 per share, for the same period in 1995.

Sales fell 20 percent to $1.47 billion from $1.84 billion in the same period a year ago.

The company’s paper business reported operating income of $58.4 million, down from $419 million in 1995. The company, which has a mill in Bucksport, Maine, said the decline was due to sharply lower prices for all pulp and paper grades.

Champion’s wood products segment reported a rise in operating income, up to $42 million from the $35 million in the same period a year ago.

Profits for the first nine months of 1996 were $131.2 million, or $1.37 cents per share, on sales of $4.45 billion. That compares with profits of $554.3 million, or $5.74 cents per share, on sales of $5.23 billion, in the same period of 1995.