This article discusses the situation for paper and paperboard mills in the U.S. as of January 1989. For two years paper demand has outstripped supply and prices have soared. The low dollar has boosted exports of paper and wood and even Canadian lumber imports, a menace for the past decade, are not so worrisome anymore. Paper manufacturers upped capital spending last year by 28%, to $11.4 billion. By 1990 it could hit $14 billion, creating some overcapacity. Strong paper markets, offsetting weakening demand for wood, drove industry profits up 44%, to a record $14 billion in 1988. They could go up 5% more this year. Paper exports, which jumped by 10% in 1987 and 6% in 1988, should grow again. The average price of paper products, up 14.5% last may rise 6% in 1989. The outlook is brightest for bleached paperboard, the kind used for aseptic packaging of foods and beverages. Newsprint is suddenly weaker. Its average price jumped 10% in 1988, to $635 a metric ton. But discounting started late last year as consumption dropped because of cutbacks in financial and retail advertising. Moreover, an expected 9% increase in new capacity over the next two years is stimulating aggressive sales approaches, says John B. Fery, chairman of Boise Cascade Corp. Production of lumber and wood paneling slumped 4% in 1988 and could slide 3% more this year, producers say.