Why was old growth liquidated by timber companies?
Alston Chase’s 1995 book, In A Dark Wood, chronicles the clash over the last century between forest productionists and forest preservationists. He wrote about the strategy of removing decadent timber from timberlands, owned by timber companies or the government (though not from parks), to make way for young trees:
[Private companies] sought to convert old, uneven-aged stands to younger, even-aged ones as rapidly as possible, thus accepting reductions in timber volume in return for increasing long-term productivity. … Once the virgin timber was gone, they intended to follow sustained yield strategies, harvesting no more timber than could be cut in perpetuity, and doing so by cutting stands when their biological or economic growth rates had reached their zenith.
Following these strategies companies started to achieve their long-term objectives.
Growth rates ballooned, by 1970 exceeding cuts by more than thirty percent nationally. … In the Douglas fir region net growth per acre (i.e. total growth less mortality) increased from under 50 cubic feet per year in 1952 to over 70 in 1970, and to 110 in 1987.
This is corroborated by Brad Smith, et. al., in Forest Resources of the United States, 2002
Since the 1950s, timber growth has consistently exceeded harvest. Net timber growth exceeded harvest by 54 percent in 1976, 36 percent in 1986, and 33 percent in 2001. Net growth rates have not been increasing as rapidly as in the past, while harvest levels have remained relatively stable since 1986. Additional resource demands have been met by increased imports.