Sustaining the Productivity of Planted Forests

Conversion of natural forests to plantations, particularly in the tropics, has drawn global attention and concern. Moreover, plantation forestry is on the rise, especially in tropical and sub-tropical regions where growth rates are rapid. Even in the United States where even-age silviculture is being de-emphasized on public land (only about 15Oh of all plantings in recent years), the area in new plantings on all ownership has averaged 1 .l 1 million ha annually for the last decade, ranging from a low of 979 thousand ha in 1993 to the all-time high of 1.37 million ha in 1988 (Moulton, et al. 1996). Most of this is in the southern pine region. Since global and domestic demands for wood products will continue to rise in the 21st century, de-emphasis of timber management on public forests and the reclassification of much natural forest tq. protected status places an unprecedented burden on planted forests on private lands to meet the needs of a wooddemanding public. Pressures will bear particularly on industrial plantations of the South and Pacific Northwest to be more productive than ever. But there is much skepticism that high rates of plantation productivity can be maintained for long periods with repeated cropping. Addressing this criticism requires a definition and understanding of productivity that cuts across all intended uses of plantations.