The Unnatural History of the Monterey Pine

With the depletion of old-growth forests in northern temperate countries, comparative advantage in forestry has shifted to regions where trees grow fast. In that transition foresters turn to the trees that grow fastest of all. Foremost among them are pine and eucalyptus, which account for more than 70 percent of all plantations in developing countries. As exotic trees in new environments, both genera have several advantages over native species. One is temporary: the predators and parasites of each tree in its endemic area are absent in its new home. Decades may pass before old predators arrive to plague the plantations or before new predators develop a taste for the exotic wood. In the case of pine and eucalyptus new pests have been few, despite the diffusion of the trees throughout the tropical and maritime temperate regions. The other advantages of pine and eucalyptus are permanent. They meet the four main requirements for plantation trees (Hartshorn 1983): they are pioneer species; they reproduce easily; they grow exceptionally fast; and the demand for their wood is reliable. Pioneer species have adapted to colonize open land: both pine and eucalyptus are hardy and fast growing, tolerant of drought, and adapted to survive fire. Their seeds germinate and root in poor soils, even on the eroded slopes of gullies where few other plants survive, which makes them attractive for the recuperation of deforested and degraded land. They reproduce successfully in nursery conditions and grow to marketable size in a generation. Within twenty years many plantation-grown pines reach the peak of their mean annual increment; several eucalyptus species are harvested in rotations as short as five years. Finally and perhaps most importantly, there are large and expanding international markets for the wood. Plantation-grown pines are especially marketable and provide adequate general-purpose construction lumber and long-fiber cellulose pulp. The market for eucalyptus pulp is more recent, but it has expanded rapidly since 1960. High-productivity silviculture increases wood yield dramatically. It has been estimated that one hectare of plantation could provide as much wood as ten hectares of natural forest (Lanly 1982), and more than a decade ago it was predicted that under plantation management a mere 5 to 10 percent of the productive forest area in the world could satisfy industrial demand (Sedjo 1983). In Chile exotic plantations almost meet those expectations: tree farms provide 85 percent of the country's wood harvest, although they are only 15 percent of the total commercial forest in area and 16 percent in wood volume (INFOR 1991). Of those plantations 85 percent are Monterey pine; the rest are mostly eucalyptus. Pine plantations now occupy 15,000 square kilometers of south-central Chile [ILLUSTRATION FOR FIGURE 1 OMITTED]. Plantation forestry dwarfs native forestry in production and profits and has displaced it in the main markets for forest products. The native forests in Chile are both depleted and degraded, and industries based on them have been in decline since the 1950s. Nevertheless, Chile boasts one of the most rapidly expanding forest-products industries in the world. Total domestic product in forestry doubled between 1983 and 1990, and export earnings tripled. The value of forest exports reached U.S.$1 billion in 1992. Its rapid growth and well-developed markets have made pine a more profitable crop than native trees or annual crops. Owners of agricultural land have an incentive to replace tenant farmers and their crops with exotic trees, and owners of forestland have an incentive to cut native trees and to plant exotics in their place. The success of exotic species in Chile and elsewhere presents a crisis - an opportunity replete with dangers, in which exotic forestry offers an alternative supply of timber and an engine of economic growth but threatens to displace both native species and rural inhabitants. …